17 files changed, 7050 insertions, 0 deletions

diff --git a/drivers/hsi/Kconfig b/drivers/hsi/Kconfig
new file mode 100644
index 000000000..42da4c235
--- /dev/null
+++ b/drivers/hsi/Kconfig
@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# HSI driver configuration
+#
+menuconfig HSI
+	tristate "HSI support"
+	help
+	  The "High speed synchronous Serial Interface" is
+	  synchronous serial interface used mainly to connect
+	  application engines and cellular modems.
+
+if HSI
+
+config HSI_BOARDINFO
+	bool
+	default y
+
+source "drivers/hsi/controllers/Kconfig"
+source "drivers/hsi/clients/Kconfig"
+
+endif # HSI
diff --git a/drivers/hsi/Makefile b/drivers/hsi/Makefile
new file mode 100644
index 000000000..53c3bcdbf
--- /dev/null
+++ b/drivers/hsi/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for HSI
+#
+obj-$(CONFIG_HSI)		+= hsi.o
+hsi-objs			:= hsi_core.o
+hsi-$(CONFIG_HSI_BOARDINFO)	+= hsi_boardinfo.o
+obj-y				+= controllers/
+obj-y				+= clients/
diff --git a/drivers/hsi/clients/Kconfig b/drivers/hsi/clients/Kconfig
new file mode 100644
index 000000000..80f60cb28
--- /dev/null
+++ b/drivers/hsi/clients/Kconfig
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# HSI clients configuration
+#
+
+comment "HSI clients"
+
+config NOKIA_MODEM
+	tristate "Nokia Modem"
+	depends on HSI && SSI_PROTOCOL && CMT_SPEECH
+	help
+	Say Y here if you want to add support for the modem on Nokia
+	N900 (Nokia RX-51) hardware.
+
+	If unsure, say N.
+
+config CMT_SPEECH
+	tristate "CMT speech"
+	depends on HSI && SSI_PROTOCOL
+	help
+	If you say Y here, you will enable the CMT speech protocol used
+	by Nokia modems. If you say M the protocol will be available as
+	module named cmt_speech.
+
+	If unsure, say N.
+
+config SSI_PROTOCOL
+	tristate "SSI protocol"
+	depends on HSI && PHONET && OMAP_SSI
+	help
+	If you say Y here, you will enable the SSI protocol aka McSAAB.
+
+	If unsure, say N.
+
+config HSI_CHAR
+	tristate "HSI/SSI character driver"
+	depends on HSI
+	help
+	  If you say Y here, you will enable the HSI/SSI character driver.
+	  This driver provides a simple character device interface for
+	  serial communication with the cellular modem over HSI/SSI bus.
diff --git a/drivers/hsi/clients/Makefile b/drivers/hsi/clients/Makefile
new file mode 100644
index 000000000..8fab835fa
--- /dev/null
+++ b/drivers/hsi/clients/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for HSI clients
+#
+
+obj-$(CONFIG_NOKIA_MODEM)	+= nokia-modem.o
+obj-$(CONFIG_SSI_PROTOCOL)	+= ssi_protocol.o
+obj-$(CONFIG_CMT_SPEECH)	+= cmt_speech.o
+obj-$(CONFIG_HSI_CHAR)		+= hsi_char.o
diff --git a/drivers/hsi/clients/cmt_speech.c b/drivers/hsi/clients/cmt_speech.c
new file mode 100644
index 000000000..89869c66f
--- /dev/null
+++ b/drivers/hsi/clients/cmt_speech.c
@@ -0,0 +1,1448 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * cmt_speech.c - HSI CMT speech driver
+ *
+ * Copyright (C) 2008,2009,2010 Nokia Corporation. All rights reserved.
+ *
+ * Contact: Kai Vehmanen <kai.vehmanen@nokia.com>
+ * Original author: Peter Ujfalusi <peter.ujfalusi@nokia.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/sched/signal.h>
+#include <linux/ioctl.h>
+#include <linux/uaccess.h>
+#include <linux/pm_qos.h>
+#include <linux/hsi/hsi.h>
+#include <linux/hsi/ssi_protocol.h>
+#include <linux/hsi/cs-protocol.h>
+
+#define CS_MMAP_SIZE	PAGE_SIZE
+
+struct char_queue {
+	struct list_head	list;
+	u32			msg;
+};
+
+struct cs_char {
+	unsigned int		opened;
+	struct hsi_client	*cl;
+	struct cs_hsi_iface	*hi;
+	struct list_head	chardev_queue;
+	struct list_head	dataind_queue;
+	int			dataind_pending;
+	/* mmap things */
+	unsigned long		mmap_base;
+	unsigned long		mmap_size;
+	spinlock_t		lock;
+	struct fasync_struct	*async_queue;
+	wait_queue_head_t	wait;
+	/* hsi channel ids */
+	int                     channel_id_cmd;
+	int                     channel_id_data;
+};
+
+#define SSI_CHANNEL_STATE_READING	1
+#define SSI_CHANNEL_STATE_WRITING	(1 << 1)
+#define SSI_CHANNEL_STATE_POLL		(1 << 2)
+#define SSI_CHANNEL_STATE_ERROR		(1 << 3)
+
+#define TARGET_MASK			0xf000000
+#define TARGET_REMOTE			(1 << CS_DOMAIN_SHIFT)
+#define TARGET_LOCAL			0
+
+/* Number of pre-allocated commands buffers */
+#define CS_MAX_CMDS		        4
+
+/*
+ * During data transfers, transactions must be handled
+ * within 20ms (fixed value in cmtspeech HSI protocol)
+ */
+#define CS_QOS_LATENCY_FOR_DATA_USEC	20000
+
+/* Timeout to wait for pending HSI transfers to complete */
+#define CS_HSI_TRANSFER_TIMEOUT_MS      500
+
+
+#define RX_PTR_BOUNDARY_SHIFT		8
+#define RX_PTR_MAX_SHIFT		(RX_PTR_BOUNDARY_SHIFT + \
+						CS_MAX_BUFFERS_SHIFT)
+struct cs_hsi_iface {
+	struct hsi_client		*cl;
+	struct hsi_client		*master;
+
+	unsigned int			iface_state;
+	unsigned int			wakeline_state;
+	unsigned int			control_state;
+	unsigned int			data_state;
+
+	/* state exposed to application */
+	struct cs_mmap_config_block	*mmap_cfg;
+
+	unsigned long			mmap_base;
+	unsigned long			mmap_size;
+
+	unsigned int			rx_slot;
+	unsigned int			tx_slot;
+
+	/* note: for security reasons, we do not trust the contents of
+	 * mmap_cfg, but instead duplicate the variables here */
+	unsigned int			buf_size;
+	unsigned int			rx_bufs;
+	unsigned int			tx_bufs;
+	unsigned int			rx_ptr_boundary;
+	unsigned int			rx_offsets[CS_MAX_BUFFERS];
+	unsigned int			tx_offsets[CS_MAX_BUFFERS];
+
+	/* size of aligned memory blocks */
+	unsigned int			slot_size;
+	unsigned int			flags;
+
+	struct list_head		cmdqueue;
+
+	struct hsi_msg			*data_rx_msg;
+	struct hsi_msg			*data_tx_msg;
+	wait_queue_head_t		datawait;
+
+	struct pm_qos_request           pm_qos_req;
+
+	spinlock_t			lock;
+};
+
+static struct cs_char cs_char_data;
+
+static void cs_hsi_read_on_control(struct cs_hsi_iface *hi);
+static void cs_hsi_read_on_data(struct cs_hsi_iface *hi);
+
+static inline void rx_ptr_shift_too_big(void)
+{
+	BUILD_BUG_ON((1LLU << RX_PTR_MAX_SHIFT) > UINT_MAX);
+}
+
+static void cs_notify(u32 message, struct list_head *head)
+{
+	struct char_queue *entry;
+
+	spin_lock(&cs_char_data.lock);
+
+	if (!cs_char_data.opened) {
+		spin_unlock(&cs_char_data.lock);
+		goto out;
+	}
+
+	entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
+	if (!entry) {
+		dev_err(&cs_char_data.cl->device,
+			"Can't allocate new entry for the queue.\n");
+		spin_unlock(&cs_char_data.lock);
+		goto out;
+	}
+
+	entry->msg = message;
+	list_add_tail(&entry->list, head);
+
+	spin_unlock(&cs_char_data.lock);
+
+	wake_up_interruptible(&cs_char_data.wait);
+	kill_fasync(&cs_char_data.async_queue, SIGIO, POLL_IN);
+
+out:
+	return;
+}
+
+static u32 cs_pop_entry(struct list_head *head)
+{
+	struct char_queue *entry;
+	u32 data;
+
+	entry = list_entry(head->next, struct char_queue, list);
+	data = entry->msg;
+	list_del(&entry->list);
+	kfree(entry);
+
+	return data;
+}
+
+static void cs_notify_control(u32 message)
+{
+	cs_notify(message, &cs_char_data.chardev_queue);
+}
+
+static void cs_notify_data(u32 message, int maxlength)
+{
+	cs_notify(message, &cs_char_data.dataind_queue);
+
+	spin_lock(&cs_char_data.lock);
+	cs_char_data.dataind_pending++;
+	while (cs_char_data.dataind_pending > maxlength &&
+				!list_empty(&cs_char_data.dataind_queue)) {
+		dev_dbg(&cs_char_data.cl->device, "data notification "
+		"queue overrun (%u entries)\n", cs_char_data.dataind_pending);
+
+		cs_pop_entry(&cs_char_data.dataind_queue);
+		cs_char_data.dataind_pending--;
+	}
+	spin_unlock(&cs_char_data.lock);
+}
+
+static inline void cs_set_cmd(struct hsi_msg *msg, u32 cmd)
+{
+	u32 *data = sg_virt(msg->sgt.sgl);
+	*data = cmd;
+}
+
+static inline u32 cs_get_cmd(struct hsi_msg *msg)
+{
+	u32 *data = sg_virt(msg->sgt.sgl);
+	return *data;
+}
+
+static void cs_release_cmd(struct hsi_msg *msg)
+{
+	struct cs_hsi_iface *hi = msg->context;
+
+	list_add_tail(&msg->link, &hi->cmdqueue);
+}
+
+static void cs_cmd_destructor(struct hsi_msg *msg)
+{
+	struct cs_hsi_iface *hi = msg->context;
+
+	spin_lock(&hi->lock);
+
+	dev_dbg(&cs_char_data.cl->device, "control cmd destructor\n");
+
+	if (hi->iface_state != CS_STATE_CLOSED)
+		dev_err(&hi->cl->device, "Cmd flushed while driver active\n");
+
+	if (msg->ttype == HSI_MSG_READ)
+		hi->control_state &=
+			~(SSI_CHANNEL_STATE_POLL | SSI_CHANNEL_STATE_READING);
+	else if (msg->ttype == HSI_MSG_WRITE &&
+			hi->control_state & SSI_CHANNEL_STATE_WRITING)
+		hi->control_state &= ~SSI_CHANNEL_STATE_WRITING;
+
+	cs_release_cmd(msg);
+
+	spin_unlock(&hi->lock);
+}
+
+static struct hsi_msg *cs_claim_cmd(struct cs_hsi_iface* ssi)
+{
+	struct hsi_msg *msg;
+
+	BUG_ON(list_empty(&ssi->cmdqueue));
+
+	msg = list_first_entry(&ssi->cmdqueue, struct hsi_msg, link);
+	list_del(&msg->link);
+	msg->destructor = cs_cmd_destructor;
+
+	return msg;
+}
+
+static void cs_free_cmds(struct cs_hsi_iface *ssi)
+{
+	struct hsi_msg *msg, *tmp;
+
+	list_for_each_entry_safe(msg, tmp, &ssi->cmdqueue, link) {
+		list_del(&msg->link);
+		msg->destructor = NULL;
+		kfree(sg_virt(msg->sgt.sgl));
+		hsi_free_msg(msg);
+	}
+}
+
+static int cs_alloc_cmds(struct cs_hsi_iface *hi)
+{
+	struct hsi_msg *msg;
+	u32 *buf;
+	unsigned int i;
+
+	INIT_LIST_HEAD(&hi->cmdqueue);
+
+	for (i = 0; i < CS_MAX_CMDS; i++) {
+		msg = hsi_alloc_msg(1, GFP_KERNEL);
+		if (!msg)
+			goto out;
+		buf = kmalloc(sizeof(*buf), GFP_KERNEL);
+		if (!buf) {
+			hsi_free_msg(msg);
+			goto out;
+		}
+		sg_init_one(msg->sgt.sgl, buf, sizeof(*buf));
+		msg->channel = cs_char_data.channel_id_cmd;
+		msg->context = hi;
+		list_add_tail(&msg->link, &hi->cmdqueue);
+	}
+
+	return 0;
+
+out:
+	cs_free_cmds(hi);
+	return -ENOMEM;
+}
+
+static void cs_hsi_data_destructor(struct hsi_msg *msg)
+{
+	struct cs_hsi_iface *hi = msg->context;
+	const char *dir = (msg->ttype == HSI_MSG_READ) ? "TX" : "RX";
+
+	dev_dbg(&cs_char_data.cl->device, "Freeing data %s message\n", dir);
+
+	spin_lock(&hi->lock);
+	if (hi->iface_state != CS_STATE_CLOSED)
+		dev_err(&cs_char_data.cl->device,
+				"Data %s flush while device active\n", dir);
+	if (msg->ttype == HSI_MSG_READ)
+		hi->data_state &=
+			~(SSI_CHANNEL_STATE_POLL | SSI_CHANNEL_STATE_READING);
+	else
+		hi->data_state &= ~SSI_CHANNEL_STATE_WRITING;
+
+	msg->status = HSI_STATUS_COMPLETED;
+	if (unlikely(waitqueue_active(&hi->datawait)))
+		wake_up_interruptible(&hi->datawait);
+
+	spin_unlock(&hi->lock);
+}
+
+static int cs_hsi_alloc_data(struct cs_hsi_iface *hi)
+{
+	struct hsi_msg *txmsg, *rxmsg;
+	int res = 0;
+
+	rxmsg = hsi_alloc_msg(1, GFP_KERNEL);
+	if (!rxmsg) {
+		res = -ENOMEM;
+		goto out1;
+	}
+	rxmsg->channel = cs_char_data.channel_id_data;
+	rxmsg->destructor = cs_hsi_data_destructor;
+	rxmsg->context = hi;
+
+	txmsg = hsi_alloc_msg(1, GFP_KERNEL);
+	if (!txmsg) {
+		res = -ENOMEM;
+		goto out2;
+	}
+	txmsg->channel = cs_char_data.channel_id_data;
+	txmsg->destructor = cs_hsi_data_destructor;
+	txmsg->context = hi;
+
+	hi->data_rx_msg = rxmsg;
+	hi->data_tx_msg = txmsg;
+
+	return 0;
+
+out2:
+	hsi_free_msg(rxmsg);
+out1:
+	return res;
+}
+
+static void cs_hsi_free_data_msg(struct hsi_msg *msg)
+{
+	WARN_ON(msg->status != HSI_STATUS_COMPLETED &&
+					msg->status != HSI_STATUS_ERROR);
+	hsi_free_msg(msg);
+}
+
+static void cs_hsi_free_data(struct cs_hsi_iface *hi)
+{
+	cs_hsi_free_data_msg(hi->data_rx_msg);
+	cs_hsi_free_data_msg(hi->data_tx_msg);
+}
+
+static inline void __cs_hsi_error_pre(struct cs_hsi_iface *hi,
+					struct hsi_msg *msg, const char *info,
+					unsigned int *state)
+{
+	spin_lock(&hi->lock);
+	dev_err(&hi->cl->device, "HSI %s error, msg %d, state %u\n",
+		info, msg->status, *state);
+}
+
+static inline void __cs_hsi_error_post(struct cs_hsi_iface *hi)
+{
+	spin_unlock(&hi->lock);
+}
+
+static inline void __cs_hsi_error_read_bits(unsigned int *state)
+{
+	*state |= SSI_CHANNEL_STATE_ERROR;
+	*state &= ~(SSI_CHANNEL_STATE_READING | SSI_CHANNEL_STATE_POLL);
+}
+
+static inline void __cs_hsi_error_write_bits(unsigned int *state)
+{
+	*state |= SSI_CHANNEL_STATE_ERROR;
+	*state &= ~SSI_CHANNEL_STATE_WRITING;
+}
+
+static void cs_hsi_control_read_error(struct cs_hsi_iface *hi,
+							struct hsi_msg *msg)
+{
+	__cs_hsi_error_pre(hi, msg, "control read", &hi->control_state);
+	cs_release_cmd(msg);
+	__cs_hsi_error_read_bits(&hi->control_state);
+	__cs_hsi_error_post(hi);
+}
+
+static void cs_hsi_control_write_error(struct cs_hsi_iface *hi,
+							struct hsi_msg *msg)
+{
+	__cs_hsi_error_pre(hi, msg, "control write", &hi->control_state);
+	cs_release_cmd(msg);
+	__cs_hsi_error_write_bits(&hi->control_state);
+	__cs_hsi_error_post(hi);
+
+}
+
+static void cs_hsi_data_read_error(struct cs_hsi_iface *hi, struct hsi_msg *msg)
+{
+	__cs_hsi_error_pre(hi, msg, "data read", &hi->data_state);
+	__cs_hsi_error_read_bits(&hi->data_state);
+	__cs_hsi_error_post(hi);
+}
+
+static void cs_hsi_data_write_error(struct cs_hsi_iface *hi,
+							struct hsi_msg *msg)
+{
+	__cs_hsi_error_pre(hi, msg, "data write", &hi->data_state);
+	__cs_hsi_error_write_bits(&hi->data_state);
+	__cs_hsi_error_post(hi);
+}
+
+static void cs_hsi_read_on_control_complete(struct hsi_msg *msg)
+{
+	u32 cmd = cs_get_cmd(msg);
+	struct cs_hsi_iface *hi = msg->context;
+
+	spin_lock(&hi->lock);
+	hi->control_state &= ~SSI_CHANNEL_STATE_READING;
+	if (msg->status == HSI_STATUS_ERROR) {
+		dev_err(&hi->cl->device, "Control RX error detected\n");
+		spin_unlock(&hi->lock);
+		cs_hsi_control_read_error(hi, msg);
+		goto out;
+	}
+	dev_dbg(&hi->cl->device, "Read on control: %08X\n", cmd);
+	cs_release_cmd(msg);
+	if (hi->flags & CS_FEAT_TSTAMP_RX_CTRL) {
+		struct timespec64 tspec;
+		struct cs_timestamp *tstamp =
+			&hi->mmap_cfg->tstamp_rx_ctrl;
+
+		ktime_get_ts64(&tspec);
+
+		tstamp->tv_sec = (__u32) tspec.tv_sec;
+		tstamp->tv_nsec = (__u32) tspec.tv_nsec;
+	}
+	spin_unlock(&hi->lock);
+
+	cs_notify_control(cmd);
+
+out:
+	cs_hsi_read_on_control(hi);
+}
+
+static void cs_hsi_peek_on_control_complete(struct hsi_msg *msg)
+{
+	struct cs_hsi_iface *hi = msg->context;
+	int ret;
+
+	if (msg->status == HSI_STATUS_ERROR) {
+		dev_err(&hi->cl->device, "Control peek RX error detected\n");
+		cs_hsi_control_read_error(hi, msg);
+		return;
+	}
+
+	WARN_ON(!(hi->control_state & SSI_CHANNEL_STATE_READING));
+
+	dev_dbg(&hi->cl->device, "Peek on control complete, reading\n");
+	msg->sgt.nents = 1;
+	msg->complete = cs_hsi_read_on_control_complete;
+	ret = hsi_async_read(hi->cl, msg);
+	if (ret)
+		cs_hsi_control_read_error(hi, msg);
+}
+
+static void cs_hsi_read_on_control(struct cs_hsi_iface *hi)
+{
+	struct hsi_msg *msg;
+	int ret;
+
+	spin_lock(&hi->lock);
+	if (hi->control_state & SSI_CHANNEL_STATE_READING) {
+		dev_err(&hi->cl->device, "Control read already pending (%d)\n",
+			hi->control_state);
+		spin_unlock(&hi->lock);
+		return;
+	}
+	if (hi->control_state & SSI_CHANNEL_STATE_ERROR) {
+		dev_err(&hi->cl->device, "Control read error (%d)\n",
+			hi->control_state);
+		spin_unlock(&hi->lock);
+		return;
+	}
+	hi->control_state |= SSI_CHANNEL_STATE_READING;
+	dev_dbg(&hi->cl->device, "Issuing RX on control\n");
+	msg = cs_claim_cmd(hi);
+	spin_unlock(&hi->lock);
+
+	msg->sgt.nents = 0;
+	msg->complete = cs_hsi_peek_on_control_complete;
+	ret = hsi_async_read(hi->cl, msg);
+	if (ret)
+		cs_hsi_control_read_error(hi, msg);
+}
+
+static void cs_hsi_write_on_control_complete(struct hsi_msg *msg)
+{
+	struct cs_hsi_iface *hi = msg->context;
+	if (msg->status == HSI_STATUS_COMPLETED) {
+		spin_lock(&hi->lock);
+		hi->control_state &= ~SSI_CHANNEL_STATE_WRITING;
+		cs_release_cmd(msg);
+		spin_unlock(&hi->lock);
+	} else if (msg->status == HSI_STATUS_ERROR) {
+		cs_hsi_control_write_error(hi, msg);
+	} else {
+		dev_err(&hi->cl->device,
+			"unexpected status in control write callback %d\n",
+			msg->status);
+	}
+}
+
+static int cs_hsi_write_on_control(struct cs_hsi_iface *hi, u32 message)
+{
+	struct hsi_msg *msg;
+	int ret;
+
+	spin_lock(&hi->lock);
+	if (hi->control_state & SSI_CHANNEL_STATE_ERROR) {
+		spin_unlock(&hi->lock);
+		return -EIO;
+	}
+	if (hi->control_state & SSI_CHANNEL_STATE_WRITING) {
+		dev_err(&hi->cl->device,
+			"Write still pending on control channel.\n");
+		spin_unlock(&hi->lock);
+		return -EBUSY;
+	}
+	hi->control_state |= SSI_CHANNEL_STATE_WRITING;
+	msg = cs_claim_cmd(hi);
+	spin_unlock(&hi->lock);
+
+	cs_set_cmd(msg, message);
+	msg->sgt.nents = 1;
+	msg->complete = cs_hsi_write_on_control_complete;
+	dev_dbg(&hi->cl->device,
+		"Sending control message %08X\n", message);
+	ret = hsi_async_write(hi->cl, msg);
+	if (ret) {
+		dev_err(&hi->cl->device,
+			"async_write failed with %d\n", ret);
+		cs_hsi_control_write_error(hi, msg);
+	}
+
+	/*
+	 * Make sure control read is always pending when issuing
+	 * new control writes. This is needed as the controller
+	 * may flush our messages if e.g. the peer device reboots
+	 * unexpectedly (and we cannot directly resubmit a new read from
+	 * the message destructor; see cs_cmd_destructor()).
+	 */
+	if (!(hi->control_state & SSI_CHANNEL_STATE_READING)) {
+		dev_err(&hi->cl->device, "Restarting control reads\n");
+		cs_hsi_read_on_control(hi);
+	}
+
+	return 0;
+}
+
+static void cs_hsi_read_on_data_complete(struct hsi_msg *msg)
+{
+	struct cs_hsi_iface *hi = msg->context;
+	u32 payload;
+
+	if (unlikely(msg->status == HSI_STATUS_ERROR)) {
+		cs_hsi_data_read_error(hi, msg);
+		return;
+	}
+
+	spin_lock(&hi->lock);
+	WARN_ON(!(hi->data_state & SSI_CHANNEL_STATE_READING));
+	hi->data_state &= ~SSI_CHANNEL_STATE_READING;
+	payload = CS_RX_DATA_RECEIVED;
+	payload |= hi->rx_slot;
+	hi->rx_slot++;
+	hi->rx_slot %= hi->rx_ptr_boundary;
+	/* expose current rx ptr in mmap area */
+	hi->mmap_cfg->rx_ptr = hi->rx_slot;
+	if (unlikely(waitqueue_active(&hi->datawait)))
+		wake_up_interruptible(&hi->datawait);
+	spin_unlock(&hi->lock);
+
+	cs_notify_data(payload, hi->rx_bufs);
+	cs_hsi_read_on_data(hi);
+}
+
+static void cs_hsi_peek_on_data_complete(struct hsi_msg *msg)
+{
+	struct cs_hsi_iface *hi = msg->context;
+	u32 *address;
+	int ret;
+
+	if (unlikely(msg->status == HSI_STATUS_ERROR)) {
+		cs_hsi_data_read_error(hi, msg);
+		return;
+	}
+	if (unlikely(hi->iface_state != CS_STATE_CONFIGURED)) {
+		dev_err(&hi->cl->device, "Data received in invalid state\n");
+		cs_hsi_data_read_error(hi, msg);
+		return;
+	}
+
+	spin_lock(&hi->lock);
+	WARN_ON(!(hi->data_state & SSI_CHANNEL_STATE_POLL));
+	hi->data_state &= ~SSI_CHANNEL_STATE_POLL;
+	hi->data_state |= SSI_CHANNEL_STATE_READING;
+	spin_unlock(&hi->lock);
+
+	address = (u32 *)(hi->mmap_base +
+				hi->rx_offsets[hi->rx_slot % hi->rx_bufs]);
+	sg_init_one(msg->sgt.sgl, address, hi->buf_size);
+	msg->sgt.nents = 1;
+	msg->complete = cs_hsi_read_on_data_complete;
+	ret = hsi_async_read(hi->cl, msg);
+	if (ret)
+		cs_hsi_data_read_error(hi, msg);
+}
+
+/*
+ * Read/write transaction is ongoing. Returns false if in
+ * SSI_CHANNEL_STATE_POLL state.
+ */
+static inline int cs_state_xfer_active(unsigned int state)
+{
+	return (state & SSI_CHANNEL_STATE_WRITING) ||
+		(state & SSI_CHANNEL_STATE_READING);
+}
+
+/*
+ * No pending read/writes
+ */
+static inline int cs_state_idle(unsigned int state)
+{
+	return !(state & ~SSI_CHANNEL_STATE_ERROR);
+}
+
+static void cs_hsi_read_on_data(struct cs_hsi_iface *hi)
+{
+	struct hsi_msg *rxmsg;
+	int ret;
+
+	spin_lock(&hi->lock);
+	if (hi->data_state &
+		(SSI_CHANNEL_STATE_READING | SSI_CHANNEL_STATE_POLL)) {
+		dev_dbg(&hi->cl->device, "Data read already pending (%u)\n",
+			hi->data_state);
+		spin_unlock(&hi->lock);
+		return;
+	}
+	hi->data_state |= SSI_CHANNEL_STATE_POLL;
+	spin_unlock(&hi->lock);
+
+	rxmsg = hi->data_rx_msg;
+	sg_init_one(rxmsg->sgt.sgl, (void *)hi->mmap_base, 0);
+	rxmsg->sgt.nents = 0;
+	rxmsg->complete = cs_hsi_peek_on_data_complete;
+
+	ret = hsi_async_read(hi->cl, rxmsg);
+	if (ret)
+		cs_hsi_data_read_error(hi, rxmsg);
+}
+
+static void cs_hsi_write_on_data_complete(struct hsi_msg *msg)
+{
+	struct cs_hsi_iface *hi = msg->context;
+
+	if (msg->status == HSI_STATUS_COMPLETED) {
+		spin_lock(&hi->lock);
+		hi->data_state &= ~SSI_CHANNEL_STATE_WRITING;
+		if (unlikely(waitqueue_active(&hi->datawait)))
+			wake_up_interruptible(&hi->datawait);
+		spin_unlock(&hi->lock);
+	} else {
+		cs_hsi_data_write_error(hi, msg);
+	}
+}
+
+static int cs_hsi_write_on_data(struct cs_hsi_iface *hi, unsigned int slot)
+{
+	u32 *address;
+	struct hsi_msg *txmsg;
+	int ret;
+
+	spin_lock(&hi->lock);
+	if (hi->iface_state != CS_STATE_CONFIGURED) {
+		dev_err(&hi->cl->device, "Not configured, aborting\n");
+		ret = -EINVAL;
+		goto error;
+	}
+	if (hi->data_state & SSI_CHANNEL_STATE_ERROR) {
+		dev_err(&hi->cl->device, "HSI error, aborting\n");
+		ret = -EIO;
+		goto error;
+	}
+	if (hi->data_state & SSI_CHANNEL_STATE_WRITING) {
+		dev_err(&hi->cl->device, "Write pending on data channel.\n");
+		ret = -EBUSY;
+		goto error;
+	}
+	hi->data_state |= SSI_CHANNEL_STATE_WRITING;
+	spin_unlock(&hi->lock);
+
+	hi->tx_slot = slot;
+	address = (u32 *)(hi->mmap_base + hi->tx_offsets[hi->tx_slot]);
+	txmsg = hi->data_tx_msg;
+	sg_init_one(txmsg->sgt.sgl, address, hi->buf_size);
+	txmsg->complete = cs_hsi_write_on_data_complete;
+	ret = hsi_async_write(hi->cl, txmsg);
+	if (ret)
+		cs_hsi_data_write_error(hi, txmsg);
+
+	return ret;
+
+error:
+	spin_unlock(&hi->lock);
+	if (ret == -EIO)
+		cs_hsi_data_write_error(hi, hi->data_tx_msg);
+
+	return ret;
+}
+
+static unsigned int cs_hsi_get_state(struct cs_hsi_iface *hi)
+{
+	return hi->iface_state;
+}
+
+static int cs_hsi_command(struct cs_hsi_iface *hi, u32 cmd)
+{
+	int ret = 0;
+
+	local_bh_disable();
+	switch (cmd & TARGET_MASK) {
+	case TARGET_REMOTE:
+		ret = cs_hsi_write_on_control(hi, cmd);
+		break;
+	case TARGET_LOCAL:
+		if ((cmd & CS_CMD_MASK) == CS_TX_DATA_READY)
+			ret = cs_hsi_write_on_data(hi, cmd & CS_PARAM_MASK);
+		else
+			ret = -EINVAL;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	local_bh_enable();
+
+	return ret;
+}
+
+static void cs_hsi_set_wakeline(struct cs_hsi_iface *hi, bool new_state)
+{
+	int change = 0;
+
+	spin_lock_bh(&hi->lock);
+	if (hi->wakeline_state != new_state) {
+		hi->wakeline_state = new_state;
+		change = 1;
+		dev_dbg(&hi->cl->device, "setting wake line to %d (%p)\n",
+			new_state, hi->cl);
+	}
+	spin_unlock_bh(&hi->lock);
+
+	if (change) {
+		if (new_state)
+			ssip_slave_start_tx(hi->master);
+		else
+			ssip_slave_stop_tx(hi->master);
+	}
+
+	dev_dbg(&hi->cl->device, "wake line set to %d (%p)\n",
+		new_state, hi->cl);
+}
+
+static void set_buffer_sizes(struct cs_hsi_iface *hi, int rx_bufs, int tx_bufs)
+{
+	hi->rx_bufs = rx_bufs;
+	hi->tx_bufs = tx_bufs;
+	hi->mmap_cfg->rx_bufs = rx_bufs;
+	hi->mmap_cfg->tx_bufs = tx_bufs;
+
+	if (hi->flags & CS_FEAT_ROLLING_RX_COUNTER) {
+		/*
+		 * For more robust overrun detection, let the rx
+		 * pointer run in range 0..'boundary-1'. Boundary
+		 * is a multiple of rx_bufs, and limited in max size
+		 * by RX_PTR_MAX_SHIFT to allow for fast ptr-diff
+		 * calculation.
+		 */
+		hi->rx_ptr_boundary = (rx_bufs << RX_PTR_BOUNDARY_SHIFT);
+		hi->mmap_cfg->rx_ptr_boundary = hi->rx_ptr_boundary;
+	} else {
+		hi->rx_ptr_boundary = hi->rx_bufs;
+	}
+}
+
+static int check_buf_params(struct cs_hsi_iface *hi,
+					const struct cs_buffer_config *buf_cfg)
+{
+	size_t buf_size_aligned = L1_CACHE_ALIGN(buf_cfg->buf_size) *
+					(buf_cfg->rx_bufs + buf_cfg->tx_bufs);
+	size_t ctrl_size_aligned = L1_CACHE_ALIGN(sizeof(*hi->mmap_cfg));
+	int r = 0;
+
+	if (buf_cfg->rx_bufs > CS_MAX_BUFFERS ||
+					buf_cfg->tx_bufs > CS_MAX_BUFFERS) {
+		r = -EINVAL;
+	} else if ((buf_size_aligned + ctrl_size_aligned) >= hi->mmap_size) {
+		dev_err(&hi->cl->device, "No space for the requested buffer "
+			"configuration\n");
+		r = -ENOBUFS;
+	}
+
+	return r;
+}
+
+/**
+ * Block until pending data transfers have completed.
+ */
+static int cs_hsi_data_sync(struct cs_hsi_iface *hi)
+{
+	int r = 0;
+
+	spin_lock_bh(&hi->lock);
+
+	if (!cs_state_xfer_active(hi->data_state)) {
+		dev_dbg(&hi->cl->device, "hsi_data_sync break, idle\n");
+		goto out;
+	}
+
+	for (;;) {
+		int s;
+		DEFINE_WAIT(wait);
+		if (!cs_state_xfer_active(hi->data_state))
+			goto out;
+		if (signal_pending(current)) {
+			r = -ERESTARTSYS;
+			goto out;
+		}
+		/**
+		 * prepare_to_wait must be called with hi->lock held
+		 * so that callbacks can check for waitqueue_active()
+		 */
+		prepare_to_wait(&hi->datawait, &wait, TASK_INTERRUPTIBLE);
+		spin_unlock_bh(&hi->lock);
+		s = schedule_timeout(
+			msecs_to_jiffies(CS_HSI_TRANSFER_TIMEOUT_MS));
+		spin_lock_bh(&hi->lock);
+		finish_wait(&hi->datawait, &wait);
+		if (!s) {
+			dev_dbg(&hi->cl->device,
+				"hsi_data_sync timeout after %d ms\n",
+				CS_HSI_TRANSFER_TIMEOUT_MS);
+			r = -EIO;
+			goto out;
+		}
+	}
+
+out:
+	spin_unlock_bh(&hi->lock);
+	dev_dbg(&hi->cl->device, "hsi_data_sync done with res %d\n", r);
+
+	return r;
+}
+
+static void cs_hsi_data_enable(struct cs_hsi_iface *hi,
+					struct cs_buffer_config *buf_cfg)
+{
+	unsigned int data_start, i;
+
+	BUG_ON(hi->buf_size == 0);
+
+	set_buffer_sizes(hi, buf_cfg->rx_bufs, buf_cfg->tx_bufs);
+
+	hi->slot_size = L1_CACHE_ALIGN(hi->buf_size);
+	dev_dbg(&hi->cl->device,
+			"setting slot size to %u, buf size %u, align %u\n",
+			hi->slot_size, hi->buf_size, L1_CACHE_BYTES);
+
+	data_start = L1_CACHE_ALIGN(sizeof(*hi->mmap_cfg));
+	dev_dbg(&hi->cl->device,
+			"setting data start at %u, cfg block %u, align %u\n",
+			data_start, sizeof(*hi->mmap_cfg), L1_CACHE_BYTES);
+
+	for (i = 0; i < hi->mmap_cfg->rx_bufs; i++) {
+		hi->rx_offsets[i] = data_start + i * hi->slot_size;
+		hi->mmap_cfg->rx_offsets[i] = hi->rx_offsets[i];
+		dev_dbg(&hi->cl->device, "DL buf #%u at %u\n",
+					i, hi->rx_offsets[i]);
+	}
+	for (i = 0; i < hi->mmap_cfg->tx_bufs; i++) {
+		hi->tx_offsets[i] = data_start +
+			(i + hi->mmap_cfg->rx_bufs) * hi->slot_size;
+		hi->mmap_cfg->tx_offsets[i] = hi->tx_offsets[i];
+		dev_dbg(&hi->cl->device, "UL buf #%u at %u\n",
+					i, hi->rx_offsets[i]);
+	}
+
+	hi->iface_state = CS_STATE_CONFIGURED;
+}
+
+static void cs_hsi_data_disable(struct cs_hsi_iface *hi, int old_state)
+{
+	if (old_state == CS_STATE_CONFIGURED) {
+		dev_dbg(&hi->cl->device,
+			"closing data channel with slot size 0\n");
+		hi->iface_state = CS_STATE_OPENED;
+	}
+}
+
+static int cs_hsi_buf_config(struct cs_hsi_iface *hi,
+					struct cs_buffer_config *buf_cfg)
+{
+	int r = 0;
+	unsigned int old_state = hi->iface_state;
+
+	spin_lock_bh(&hi->lock);
+	/* Prevent new transactions during buffer reconfig */
+	if (old_state == CS_STATE_CONFIGURED)
+		hi->iface_state = CS_STATE_OPENED;
+	spin_unlock_bh(&hi->lock);
+
+	/*
+	 * make sure that no non-zero data reads are ongoing before
+	 * proceeding to change the buffer layout
+	 */
+	r = cs_hsi_data_sync(hi);
+	if (r < 0)
+		return r;
+
+	WARN_ON(cs_state_xfer_active(hi->data_state));
+
+	spin_lock_bh(&hi->lock);
+	r = check_buf_params(hi, buf_cfg);
+	if (r < 0)
+		goto error;
+
+	hi->buf_size = buf_cfg->buf_size;
+	hi->mmap_cfg->buf_size = hi->buf_size;
+	hi->flags = buf_cfg->flags;
+
+	hi->rx_slot = 0;
+	hi->tx_slot = 0;
+	hi->slot_size = 0;
+
+	if (hi->buf_size)
+		cs_hsi_data_enable(hi, buf_cfg);
+	else
+		cs_hsi_data_disable(hi, old_state);
+
+	spin_unlock_bh(&hi->lock);
+
+	if (old_state != hi->iface_state) {
+		if (hi->iface_state == CS_STATE_CONFIGURED) {
+			cpu_latency_qos_add_request(&hi->pm_qos_req,
+				CS_QOS_LATENCY_FOR_DATA_USEC);
+			local_bh_disable();
+			cs_hsi_read_on_data(hi);
+			local_bh_enable();
+		} else if (old_state == CS_STATE_CONFIGURED) {
+			cpu_latency_qos_remove_request(&hi->pm_qos_req);
+		}
+	}
+	return r;
+
+error:
+	spin_unlock_bh(&hi->lock);
+	return r;
+}
+
+static int cs_hsi_start(struct cs_hsi_iface **hi, struct hsi_client *cl,
+			unsigned long mmap_base, unsigned long mmap_size)
+{
+	int err = 0;
+	struct cs_hsi_iface *hsi_if = kzalloc(sizeof(*hsi_if), GFP_KERNEL);
+
+	dev_dbg(&cl->device, "cs_hsi_start\n");
+
+	if (!hsi_if) {
+		err = -ENOMEM;
+		goto leave0;
+	}
+	spin_lock_init(&hsi_if->lock);
+	hsi_if->cl = cl;
+	hsi_if->iface_state = CS_STATE_CLOSED;
+	hsi_if->mmap_cfg = (struct cs_mmap_config_block *)mmap_base;
+	hsi_if->mmap_base = mmap_base;
+	hsi_if->mmap_size = mmap_size;
+	memset(hsi_if->mmap_cfg, 0, sizeof(*hsi_if->mmap_cfg));
+	init_waitqueue_head(&hsi_if->datawait);
+	err = cs_alloc_cmds(hsi_if);
+	if (err < 0) {
+		dev_err(&cl->device, "Unable to alloc HSI messages\n");
+		goto leave1;
+	}
+	err = cs_hsi_alloc_data(hsi_if);
+	if (err < 0) {
+		dev_err(&cl->device, "Unable to alloc HSI messages for data\n");
+		goto leave2;
+	}
+	err = hsi_claim_port(cl, 1);
+	if (err < 0) {
+		dev_err(&cl->device,
+				"Could not open, HSI port already claimed\n");
+		goto leave3;
+	}
+	hsi_if->master = ssip_slave_get_master(cl);
+	if (IS_ERR(hsi_if->master)) {
+		err = PTR_ERR(hsi_if->master);
+		dev_err(&cl->device, "Could not get HSI master client\n");
+		goto leave4;
+	}
+	if (!ssip_slave_running(hsi_if->master)) {
+		err = -ENODEV;
+		dev_err(&cl->device,
+				"HSI port not initialized\n");
+		goto leave4;
+	}
+
+	hsi_if->iface_state = CS_STATE_OPENED;
+	local_bh_disable();
+	cs_hsi_read_on_control(hsi_if);
+	local_bh_enable();
+
+	dev_dbg(&cl->device, "cs_hsi_start...done\n");
+
+	BUG_ON(!hi);
+	*hi = hsi_if;
+
+	return 0;
+
+leave4:
+	hsi_release_port(cl);
+leave3:
+	cs_hsi_free_data(hsi_if);
+leave2:
+	cs_free_cmds(hsi_if);
+leave1:
+	kfree(hsi_if);
+leave0:
+	dev_dbg(&cl->device, "cs_hsi_start...done/error\n\n");
+
+	return err;
+}
+
+static void cs_hsi_stop(struct cs_hsi_iface *hi)
+{
+	dev_dbg(&hi->cl->device, "cs_hsi_stop\n");
+	cs_hsi_set_wakeline(hi, 0);
+	ssip_slave_put_master(hi->master);
+
+	/* hsi_release_port() needs to be called with CS_STATE_CLOSED */
+	hi->iface_state = CS_STATE_CLOSED;
+	hsi_release_port(hi->cl);
+
+	/*
+	 * hsi_release_port() should flush out all the pending
+	 * messages, so cs_state_idle() should be true for both
+	 * control and data channels.
+	 */
+	WARN_ON(!cs_state_idle(hi->control_state));
+	WARN_ON(!cs_state_idle(hi->data_state));
+
+	if (cpu_latency_qos_request_active(&hi->pm_qos_req))
+		cpu_latency_qos_remove_request(&hi->pm_qos_req);
+
+	spin_lock_bh(&hi->lock);
+	cs_hsi_free_data(hi);
+	cs_free_cmds(hi);
+	spin_unlock_bh(&hi->lock);
+	kfree(hi);
+}
+
+static vm_fault_t cs_char_vma_fault(struct vm_fault *vmf)
+{
+	struct cs_char *csdata = vmf->vma->vm_private_data;
+	struct page *page;
+
+	page = virt_to_page(csdata->mmap_base);
+	get_page(page);
+	vmf->page = page;
+
+	return 0;
+}
+
+static const struct vm_operations_struct cs_char_vm_ops = {
+	.fault	= cs_char_vma_fault,
+};
+
+static int cs_char_fasync(int fd, struct file *file, int on)
+{
+	struct cs_char *csdata = file->private_data;
+
+	if (fasync_helper(fd, file, on, &csdata->async_queue) < 0)
+		return -EIO;
+
+	return 0;
+}
+
+static __poll_t cs_char_poll(struct file *file, poll_table *wait)
+{
+	struct cs_char *csdata = file->private_data;
+	__poll_t ret = 0;
+
+	poll_wait(file, &cs_char_data.wait, wait);
+	spin_lock_bh(&csdata->lock);
+	if (!list_empty(&csdata->chardev_queue))
+		ret = EPOLLIN | EPOLLRDNORM;
+	else if (!list_empty(&csdata->dataind_queue))
+		ret = EPOLLIN | EPOLLRDNORM;
+	spin_unlock_bh(&csdata->lock);
+
+	return ret;
+}
+
+static ssize_t cs_char_read(struct file *file, char __user *buf, size_t count,
+								loff_t *unused)
+{
+	struct cs_char *csdata = file->private_data;
+	u32 data;
+	ssize_t retval;
+
+	if (count < sizeof(data))
+		return -EINVAL;
+
+	for (;;) {
+		DEFINE_WAIT(wait);
+
+		spin_lock_bh(&csdata->lock);
+		if (!list_empty(&csdata->chardev_queue)) {
+			data = cs_pop_entry(&csdata->chardev_queue);
+		} else if (!list_empty(&csdata->dataind_queue)) {
+			data = cs_pop_entry(&csdata->dataind_queue);
+			csdata->dataind_pending--;
+		} else {
+			data = 0;
+		}
+		spin_unlock_bh(&csdata->lock);
+
+		if (data)
+			break;
+		if (file->f_flags & O_NONBLOCK) {
+			retval = -EAGAIN;
+			goto out;
+		} else if (signal_pending(current)) {
+			retval = -ERESTARTSYS;
+			goto out;
+		}
+		prepare_to_wait_exclusive(&csdata->wait, &wait,
+						TASK_INTERRUPTIBLE);
+		schedule();
+		finish_wait(&csdata->wait, &wait);
+	}
+
+	retval = put_user(data, (u32 __user *)buf);
+	if (!retval)
+		retval = sizeof(data);
+
+out:
+	return retval;
+}
+
+static ssize_t cs_char_write(struct file *file, const char __user *buf,
+						size_t count, loff_t *unused)
+{
+	struct cs_char *csdata = file->private_data;
+	u32 data;
+	int err;
+	ssize_t	retval;
+
+	if (count < sizeof(data))
+		return -EINVAL;
+
+	if (get_user(data, (u32 __user *)buf))
+		retval = -EFAULT;
+	else
+		retval = count;
+
+	err = cs_hsi_command(csdata->hi, data);
+	if (err < 0)
+		retval = err;
+
+	return retval;
+}
+
+static long cs_char_ioctl(struct file *file, unsigned int cmd,
+				unsigned long arg)
+{
+	struct cs_char *csdata = file->private_data;
+	int r = 0;
+
+	switch (cmd) {
+	case CS_GET_STATE: {
+		unsigned int state;
+
+		state = cs_hsi_get_state(csdata->hi);
+		if (copy_to_user((void __user *)arg, &state, sizeof(state)))
+			r = -EFAULT;
+
+		break;
+	}
+	case CS_SET_WAKELINE: {
+		unsigned int state;
+
+		if (copy_from_user(&state, (void __user *)arg, sizeof(state))) {
+			r = -EFAULT;
+			break;
+		}
+
+		if (state > 1) {
+			r = -EINVAL;
+			break;
+		}
+
+		cs_hsi_set_wakeline(csdata->hi, !!state);
+
+		break;
+	}
+	case CS_GET_IF_VERSION: {
+		unsigned int ifver = CS_IF_VERSION;
+
+		if (copy_to_user((void __user *)arg, &ifver, sizeof(ifver)))
+			r = -EFAULT;
+
+		break;
+	}
+	case CS_CONFIG_BUFS: {
+		struct cs_buffer_config buf_cfg;
+
+		if (copy_from_user(&buf_cfg, (void __user *)arg,
+							sizeof(buf_cfg)))
+			r = -EFAULT;
+		else
+			r = cs_hsi_buf_config(csdata->hi, &buf_cfg);
+
+		break;
+	}
+	default:
+		r = -ENOTTY;
+		break;
+	}
+
+	return r;
+}
+
+static int cs_char_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	if (vma->vm_end < vma->vm_start)
+		return -EINVAL;
+
+	if (vma_pages(vma) != 1)
+		return -EINVAL;
+
+	vma->vm_flags |= VM_IO | VM_DONTDUMP | VM_DONTEXPAND;
+	vma->vm_ops = &cs_char_vm_ops;
+	vma->vm_private_data = file->private_data;
+
+	return 0;
+}
+
+static int cs_char_open(struct inode *unused, struct file *file)
+{
+	int ret = 0;
+	unsigned long p;
+
+	spin_lock_bh(&cs_char_data.lock);
+	if (cs_char_data.opened) {
+		ret = -EBUSY;
+		spin_unlock_bh(&cs_char_data.lock);
+		goto out1;
+	}
+	cs_char_data.opened = 1;
+	cs_char_data.dataind_pending = 0;
+	spin_unlock_bh(&cs_char_data.lock);
+
+	p = get_zeroed_page(GFP_KERNEL);
+	if (!p) {
+		ret = -ENOMEM;
+		goto out2;
+	}
+
+	ret = cs_hsi_start(&cs_char_data.hi, cs_char_data.cl, p, CS_MMAP_SIZE);
+	if (ret) {
+		dev_err(&cs_char_data.cl->device, "Unable to initialize HSI\n");
+		goto out3;
+	}
+
+	/* these are only used in release so lock not needed */
+	cs_char_data.mmap_base = p;
+	cs_char_data.mmap_size = CS_MMAP_SIZE;
+
+	file->private_data = &cs_char_data;
+
+	return 0;
+
+out3:
+	free_page(p);
+out2:
+	spin_lock_bh(&cs_char_data.lock);
+	cs_char_data.opened = 0;
+	spin_unlock_bh(&cs_char_data.lock);
+out1:
+	return ret;
+}
+
+static void cs_free_char_queue(struct list_head *head)
+{
+	struct char_queue *entry;
+	struct list_head *cursor, *next;
+
+	if (!list_empty(head)) {
+		list_for_each_safe(cursor, next, head) {
+			entry = list_entry(cursor, struct char_queue, list);
+			list_del(&entry->list);
+			kfree(entry);
+		}
+	}
+
+}
+
+static int cs_char_release(struct inode *unused, struct file *file)
+{
+	struct cs_char *csdata = file->private_data;
+
+	cs_hsi_stop(csdata->hi);
+	spin_lock_bh(&csdata->lock);
+	csdata->hi = NULL;
+	free_page(csdata->mmap_base);
+	cs_free_char_queue(&csdata->chardev_queue);
+	cs_free_char_queue(&csdata->dataind_queue);
+	csdata->opened = 0;
+	spin_unlock_bh(&csdata->lock);
+
+	return 0;
+}
+
+static const struct file_operations cs_char_fops = {
+	.owner		= THIS_MODULE,
+	.read		= cs_char_read,
+	.write		= cs_char_write,
+	.poll		= cs_char_poll,
+	.unlocked_ioctl	= cs_char_ioctl,
+	.mmap		= cs_char_mmap,
+	.open		= cs_char_open,
+	.release	= cs_char_release,
+	.fasync		= cs_char_fasync,
+};
+
+static struct miscdevice cs_char_miscdev = {
+	.minor	= MISC_DYNAMIC_MINOR,
+	.name	= "cmt_speech",
+	.fops	= &cs_char_fops
+};
+
+static int cs_hsi_client_probe(struct device *dev)
+{
+	int err = 0;
+	struct hsi_client *cl = to_hsi_client(dev);
+
+	dev_dbg(dev, "hsi_client_probe\n");
+	init_waitqueue_head(&cs_char_data.wait);
+	spin_lock_init(&cs_char_data.lock);
+	cs_char_data.opened = 0;
+	cs_char_data.cl = cl;
+	cs_char_data.hi = NULL;
+	INIT_LIST_HEAD(&cs_char_data.chardev_queue);
+	INIT_LIST_HEAD(&cs_char_data.dataind_queue);
+
+	cs_char_data.channel_id_cmd = hsi_get_channel_id_by_name(cl,
+		"speech-control");
+	if (cs_char_data.channel_id_cmd < 0) {
+		err = cs_char_data.channel_id_cmd;
+		dev_err(dev, "Could not get cmd channel (%d)\n", err);
+		return err;
+	}
+
+	cs_char_data.channel_id_data = hsi_get_channel_id_by_name(cl,
+		"speech-data");
+	if (cs_char_data.channel_id_data < 0) {
+		err = cs_char_data.channel_id_data;
+		dev_err(dev, "Could not get data channel (%d)\n", err);
+		return err;
+	}
+
+	err = misc_register(&cs_char_miscdev);
+	if (err)
+		dev_err(dev, "Failed to register: %d\n", err);
+
+	return err;
+}
+
+static int cs_hsi_client_remove(struct device *dev)
+{
+	struct cs_hsi_iface *hi;
+
+	dev_dbg(dev, "hsi_client_remove\n");
+	misc_deregister(&cs_char_miscdev);
+	spin_lock_bh(&cs_char_data.lock);
+	hi = cs_char_data.hi;
+	cs_char_data.hi = NULL;
+	spin_unlock_bh(&cs_char_data.lock);
+	if (hi)
+		cs_hsi_stop(hi);
+
+	return 0;
+}
+
+static struct hsi_client_driver cs_hsi_driver = {
+	.driver = {
+		.name	= "cmt-speech",
+		.owner	= THIS_MODULE,
+		.probe	= cs_hsi_client_probe,
+		.remove	= cs_hsi_client_remove,
+	},
+};
+
+static int __init cs_char_init(void)
+{
+	pr_info("CMT speech driver added\n");
+	return hsi_register_client_driver(&cs_hsi_driver);
+}
+module_init(cs_char_init);
+
+static void __exit cs_char_exit(void)
+{
+	hsi_unregister_client_driver(&cs_hsi_driver);
+	pr_info("CMT speech driver removed\n");
+}
+module_exit(cs_char_exit);
+
+MODULE_ALIAS("hsi:cmt-speech");
+MODULE_AUTHOR("Kai Vehmanen <kai.vehmanen@nokia.com>");
+MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@nokia.com>");
+MODULE_DESCRIPTION("CMT speech driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/hsi/clients/hsi_char.c b/drivers/hsi/clients/hsi_char.c
new file mode 100644
index 000000000..71ce7dbfe
--- /dev/null
+++ b/drivers/hsi/clients/hsi_char.c
@@ -0,0 +1,788 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HSI character device driver, implements the character device
+ * interface.
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ *
+ * Contact: Andras Domokos <andras.domokos@nokia.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/atomic.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/kmemleak.h>
+#include <linux/ioctl.h>
+#include <linux/wait.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/device.h>
+#include <linux/cdev.h>
+#include <linux/uaccess.h>
+#include <linux/scatterlist.h>
+#include <linux/stat.h>
+#include <linux/hsi/hsi.h>
+#include <linux/hsi/hsi_char.h>
+
+#define HSC_DEVS		16 /* Num of channels */
+#define HSC_MSGS		4
+
+#define HSC_RXBREAK		0
+
+#define HSC_ID_BITS		6
+#define HSC_PORT_ID_BITS	4
+#define HSC_ID_MASK		3
+#define HSC_PORT_ID_MASK	3
+#define HSC_CH_MASK		0xf
+
+/*
+ * We support up to 4 controllers that can have up to 4
+ * ports, which should currently be more than enough.
+ */
+#define HSC_BASEMINOR(id, port_id) \
+		((((id) & HSC_ID_MASK) << HSC_ID_BITS) | \
+		(((port_id) & HSC_PORT_ID_MASK) << HSC_PORT_ID_BITS))
+
+enum {
+	HSC_CH_OPEN,
+	HSC_CH_READ,
+	HSC_CH_WRITE,
+	HSC_CH_WLINE,
+};
+
+enum {
+	HSC_RX,
+	HSC_TX,
+};
+
+struct hsc_client_data;
+/**
+ * struct hsc_channel - hsi_char internal channel data
+ * @ch: channel number
+ * @flags: Keeps state of the channel (open/close, reading, writing)
+ * @free_msgs_list: List of free HSI messages/requests
+ * @rx_msgs_queue: List of pending RX requests
+ * @tx_msgs_queue: List of pending TX requests
+ * @lock: Serialize access to the lists
+ * @cl: reference to the associated hsi_client
+ * @cl_data: reference to the client data that this channels belongs to
+ * @rx_wait: RX requests wait queue
+ * @tx_wait: TX requests wait queue
+ */
+struct hsc_channel {
+	unsigned int		ch;
+	unsigned long		flags;
+	struct list_head	free_msgs_list;
+	struct list_head	rx_msgs_queue;
+	struct list_head	tx_msgs_queue;
+	spinlock_t		lock;
+	struct hsi_client	*cl;
+	struct hsc_client_data *cl_data;
+	wait_queue_head_t	rx_wait;
+	wait_queue_head_t	tx_wait;
+};
+
+/**
+ * struct hsc_client_data - hsi_char internal client data
+ * @cdev: Characther device associated to the hsi_client
+ * @lock: Lock to serialize open/close access
+ * @flags: Keeps track of port state (rx hwbreak armed)
+ * @usecnt: Use count for claiming the HSI port (mutex protected)
+ * @cl: Referece to the HSI client
+ * @channels: Array of channels accessible by the client
+ */
+struct hsc_client_data {
+	struct cdev		cdev;
+	struct mutex		lock;
+	unsigned long		flags;
+	unsigned int		usecnt;
+	struct hsi_client	*cl;
+	struct hsc_channel	channels[HSC_DEVS];
+};
+
+/* Stores the major number dynamically allocated for hsi_char */
+static unsigned int hsc_major;
+/* Maximum buffer size that hsi_char will accept from userspace */
+static unsigned int max_data_size = 0x1000;
+module_param(max_data_size, uint, 0);
+MODULE_PARM_DESC(max_data_size, "max read/write data size [4,8..65536] (^2)");
+
+static void hsc_add_tail(struct hsc_channel *channel, struct hsi_msg *msg,
+							struct list_head *queue)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&channel->lock, flags);
+	list_add_tail(&msg->link, queue);
+	spin_unlock_irqrestore(&channel->lock, flags);
+}
+
+static struct hsi_msg *hsc_get_first_msg(struct hsc_channel *channel,
+							struct list_head *queue)
+{
+	struct hsi_msg *msg = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&channel->lock, flags);
+
+	if (list_empty(queue))
+		goto out;
+
+	msg = list_first_entry(queue, struct hsi_msg, link);
+	list_del(&msg->link);
+out:
+	spin_unlock_irqrestore(&channel->lock, flags);
+
+	return msg;
+}
+
+static inline void hsc_msg_free(struct hsi_msg *msg)
+{
+	kfree(sg_virt(msg->sgt.sgl));
+	hsi_free_msg(msg);
+}
+
+static void hsc_free_list(struct list_head *list)
+{
+	struct hsi_msg *msg, *tmp;
+
+	list_for_each_entry_safe(msg, tmp, list, link) {
+		list_del(&msg->link);
+		hsc_msg_free(msg);
+	}
+}
+
+static void hsc_reset_list(struct hsc_channel *channel, struct list_head *l)
+{
+	unsigned long flags;
+	LIST_HEAD(list);
+
+	spin_lock_irqsave(&channel->lock, flags);
+	list_splice_init(l, &list);
+	spin_unlock_irqrestore(&channel->lock, flags);
+
+	hsc_free_list(&list);
+}
+
+static inline struct hsi_msg *hsc_msg_alloc(unsigned int alloc_size)
+{
+	struct hsi_msg *msg;
+	void *buf;
+
+	msg = hsi_alloc_msg(1, GFP_KERNEL);
+	if (!msg)
+		goto out;
+	buf = kmalloc(alloc_size, GFP_KERNEL);
+	if (!buf) {
+		hsi_free_msg(msg);
+		goto out;
+	}
+	sg_init_one(msg->sgt.sgl, buf, alloc_size);
+	/* Ignore false positive, due to sg pointer handling */
+	kmemleak_ignore(buf);
+
+	return msg;
+out:
+	return NULL;
+}
+
+static inline int hsc_msgs_alloc(struct hsc_channel *channel)
+{
+	struct hsi_msg *msg;
+	int i;
+
+	for (i = 0; i < HSC_MSGS; i++) {
+		msg = hsc_msg_alloc(max_data_size);
+		if (!msg)
+			goto out;
+		msg->channel = channel->ch;
+		list_add_tail(&msg->link, &channel->free_msgs_list);
+	}
+
+	return 0;
+out:
+	hsc_free_list(&channel->free_msgs_list);
+
+	return -ENOMEM;
+}
+
+static inline unsigned int hsc_msg_len_get(struct hsi_msg *msg)
+{
+	return msg->sgt.sgl->length;
+}
+
+static inline void hsc_msg_len_set(struct hsi_msg *msg, unsigned int len)
+{
+	msg->sgt.sgl->length = len;
+}
+
+static void hsc_rx_completed(struct hsi_msg *msg)
+{
+	struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
+	struct hsc_channel *channel = cl_data->channels + msg->channel;
+
+	if (test_bit(HSC_CH_READ, &channel->flags)) {
+		hsc_add_tail(channel, msg, &channel->rx_msgs_queue);
+		wake_up(&channel->rx_wait);
+	} else {
+		hsc_add_tail(channel, msg, &channel->free_msgs_list);
+	}
+}
+
+static void hsc_rx_msg_destructor(struct hsi_msg *msg)
+{
+	msg->status = HSI_STATUS_ERROR;
+	hsc_msg_len_set(msg, 0);
+	hsc_rx_completed(msg);
+}
+
+static void hsc_tx_completed(struct hsi_msg *msg)
+{
+	struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
+	struct hsc_channel *channel = cl_data->channels + msg->channel;
+
+	if (test_bit(HSC_CH_WRITE, &channel->flags)) {
+		hsc_add_tail(channel, msg, &channel->tx_msgs_queue);
+		wake_up(&channel->tx_wait);
+	} else {
+		hsc_add_tail(channel, msg, &channel->free_msgs_list);
+	}
+}
+
+static void hsc_tx_msg_destructor(struct hsi_msg *msg)
+{
+	msg->status = HSI_STATUS_ERROR;
+	hsc_msg_len_set(msg, 0);
+	hsc_tx_completed(msg);
+}
+
+static void hsc_break_req_destructor(struct hsi_msg *msg)
+{
+	struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
+
+	hsi_free_msg(msg);
+	clear_bit(HSC_RXBREAK, &cl_data->flags);
+}
+
+static void hsc_break_received(struct hsi_msg *msg)
+{
+	struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
+	struct hsc_channel *channel = cl_data->channels;
+	int i, ret;
+
+	/* Broadcast HWBREAK on all channels */
+	for (i = 0; i < HSC_DEVS; i++, channel++) {
+		struct hsi_msg *msg2;
+
+		if (!test_bit(HSC_CH_READ, &channel->flags))
+			continue;
+		msg2 = hsc_get_first_msg(channel, &channel->free_msgs_list);
+		if (!msg2)
+			continue;
+		clear_bit(HSC_CH_READ, &channel->flags);
+		hsc_msg_len_set(msg2, 0);
+		msg2->status = HSI_STATUS_COMPLETED;
+		hsc_add_tail(channel, msg2, &channel->rx_msgs_queue);
+		wake_up(&channel->rx_wait);
+	}
+	hsi_flush(msg->cl);
+	ret = hsi_async_read(msg->cl, msg);
+	if (ret < 0)
+		hsc_break_req_destructor(msg);
+}
+
+static int hsc_break_request(struct hsi_client *cl)
+{
+	struct hsc_client_data *cl_data = hsi_client_drvdata(cl);
+	struct hsi_msg *msg;
+	int ret;
+
+	if (test_and_set_bit(HSC_RXBREAK, &cl_data->flags))
+		return -EBUSY;
+
+	msg = hsi_alloc_msg(0, GFP_KERNEL);
+	if (!msg) {
+		clear_bit(HSC_RXBREAK, &cl_data->flags);
+		return -ENOMEM;
+	}
+	msg->break_frame = 1;
+	msg->complete = hsc_break_received;
+	msg->destructor = hsc_break_req_destructor;
+	ret = hsi_async_read(cl, msg);
+	if (ret < 0)
+		hsc_break_req_destructor(msg);
+
+	return ret;
+}
+
+static int hsc_break_send(struct hsi_client *cl)
+{
+	struct hsi_msg *msg;
+	int ret;
+
+	msg = hsi_alloc_msg(0, GFP_ATOMIC);
+	if (!msg)
+		return -ENOMEM;
+	msg->break_frame = 1;
+	msg->complete = hsi_free_msg;
+	msg->destructor = hsi_free_msg;
+	ret = hsi_async_write(cl, msg);
+	if (ret < 0)
+		hsi_free_msg(msg);
+
+	return ret;
+}
+
+static int hsc_rx_set(struct hsi_client *cl, struct hsc_rx_config *rxc)
+{
+	struct hsi_config tmp;
+	int ret;
+
+	if ((rxc->mode != HSI_MODE_STREAM) && (rxc->mode != HSI_MODE_FRAME))
+		return -EINVAL;
+	if ((rxc->channels == 0) || (rxc->channels > HSC_DEVS))
+		return -EINVAL;
+	if (rxc->channels & (rxc->channels - 1))
+		return -EINVAL;
+	if ((rxc->flow != HSI_FLOW_SYNC) && (rxc->flow != HSI_FLOW_PIPE))
+		return -EINVAL;
+	tmp = cl->rx_cfg;
+	cl->rx_cfg.mode = rxc->mode;
+	cl->rx_cfg.num_hw_channels = rxc->channels;
+	cl->rx_cfg.flow = rxc->flow;
+	ret = hsi_setup(cl);
+	if (ret < 0) {
+		cl->rx_cfg = tmp;
+		return ret;
+	}
+	if (rxc->mode == HSI_MODE_FRAME)
+		hsc_break_request(cl);
+
+	return ret;
+}
+
+static inline void hsc_rx_get(struct hsi_client *cl, struct hsc_rx_config *rxc)
+{
+	rxc->mode = cl->rx_cfg.mode;
+	rxc->channels = cl->rx_cfg.num_hw_channels;
+	rxc->flow = cl->rx_cfg.flow;
+}
+
+static int hsc_tx_set(struct hsi_client *cl, struct hsc_tx_config *txc)
+{
+	struct hsi_config tmp;
+	int ret;
+
+	if ((txc->mode != HSI_MODE_STREAM) && (txc->mode != HSI_MODE_FRAME))
+		return -EINVAL;
+	if ((txc->channels == 0) || (txc->channels > HSC_DEVS))
+		return -EINVAL;
+	if (txc->channels & (txc->channels - 1))
+		return -EINVAL;
+	if ((txc->arb_mode != HSI_ARB_RR) && (txc->arb_mode != HSI_ARB_PRIO))
+		return -EINVAL;
+	tmp = cl->tx_cfg;
+	cl->tx_cfg.mode = txc->mode;
+	cl->tx_cfg.num_hw_channels = txc->channels;
+	cl->tx_cfg.speed = txc->speed;
+	cl->tx_cfg.arb_mode = txc->arb_mode;
+	ret = hsi_setup(cl);
+	if (ret < 0) {
+		cl->tx_cfg = tmp;
+		return ret;
+	}
+
+	return ret;
+}
+
+static inline void hsc_tx_get(struct hsi_client *cl, struct hsc_tx_config *txc)
+{
+	txc->mode = cl->tx_cfg.mode;
+	txc->channels = cl->tx_cfg.num_hw_channels;
+	txc->speed = cl->tx_cfg.speed;
+	txc->arb_mode = cl->tx_cfg.arb_mode;
+}
+
+static ssize_t hsc_read(struct file *file, char __user *buf, size_t len,
+						loff_t *ppos __maybe_unused)
+{
+	struct hsc_channel *channel = file->private_data;
+	struct hsi_msg *msg;
+	ssize_t ret;
+
+	if (len == 0)
+		return 0;
+	if (!IS_ALIGNED(len, sizeof(u32)))
+		return -EINVAL;
+	if (len > max_data_size)
+		len = max_data_size;
+	if (channel->ch >= channel->cl->rx_cfg.num_hw_channels)
+		return -ECHRNG;
+	if (test_and_set_bit(HSC_CH_READ, &channel->flags))
+		return -EBUSY;
+	msg = hsc_get_first_msg(channel, &channel->free_msgs_list);
+	if (!msg) {
+		ret = -ENOSPC;
+		goto out;
+	}
+	hsc_msg_len_set(msg, len);
+	msg->complete = hsc_rx_completed;
+	msg->destructor = hsc_rx_msg_destructor;
+	ret = hsi_async_read(channel->cl, msg);
+	if (ret < 0) {
+		hsc_add_tail(channel, msg, &channel->free_msgs_list);
+		goto out;
+	}
+
+	ret = wait_event_interruptible(channel->rx_wait,
+					!list_empty(&channel->rx_msgs_queue));
+	if (ret < 0) {
+		clear_bit(HSC_CH_READ, &channel->flags);
+		hsi_flush(channel->cl);
+		return -EINTR;
+	}
+
+	msg = hsc_get_first_msg(channel, &channel->rx_msgs_queue);
+	if (msg) {
+		if (msg->status != HSI_STATUS_ERROR) {
+			ret = copy_to_user((void __user *)buf,
+			sg_virt(msg->sgt.sgl), hsc_msg_len_get(msg));
+			if (ret)
+				ret = -EFAULT;
+			else
+				ret = hsc_msg_len_get(msg);
+		} else {
+			ret = -EIO;
+		}
+		hsc_add_tail(channel, msg, &channel->free_msgs_list);
+	}
+out:
+	clear_bit(HSC_CH_READ, &channel->flags);
+
+	return ret;
+}
+
+static ssize_t hsc_write(struct file *file, const char __user *buf, size_t len,
+						loff_t *ppos __maybe_unused)
+{
+	struct hsc_channel *channel = file->private_data;
+	struct hsi_msg *msg;
+	ssize_t ret;
+
+	if ((len == 0) || !IS_ALIGNED(len, sizeof(u32)))
+		return -EINVAL;
+	if (len > max_data_size)
+		len = max_data_size;
+	if (channel->ch >= channel->cl->tx_cfg.num_hw_channels)
+		return -ECHRNG;
+	if (test_and_set_bit(HSC_CH_WRITE, &channel->flags))
+		return -EBUSY;
+	msg = hsc_get_first_msg(channel, &channel->free_msgs_list);
+	if (!msg) {
+		clear_bit(HSC_CH_WRITE, &channel->flags);
+		return -ENOSPC;
+	}
+	if (copy_from_user(sg_virt(msg->sgt.sgl), (void __user *)buf, len)) {
+		ret = -EFAULT;
+		goto out;
+	}
+	hsc_msg_len_set(msg, len);
+	msg->complete = hsc_tx_completed;
+	msg->destructor = hsc_tx_msg_destructor;
+	ret = hsi_async_write(channel->cl, msg);
+	if (ret < 0)
+		goto out;
+
+	ret = wait_event_interruptible(channel->tx_wait,
+					!list_empty(&channel->tx_msgs_queue));
+	if (ret < 0) {
+		clear_bit(HSC_CH_WRITE, &channel->flags);
+		hsi_flush(channel->cl);
+		return -EINTR;
+	}
+
+	msg = hsc_get_first_msg(channel, &channel->tx_msgs_queue);
+	if (msg) {
+		if (msg->status == HSI_STATUS_ERROR)
+			ret = -EIO;
+		else
+			ret = hsc_msg_len_get(msg);
+
+		hsc_add_tail(channel, msg, &channel->free_msgs_list);
+	}
+out:
+	clear_bit(HSC_CH_WRITE, &channel->flags);
+
+	return ret;
+}
+
+static long hsc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct hsc_channel *channel = file->private_data;
+	unsigned int state;
+	struct hsc_rx_config rxc;
+	struct hsc_tx_config txc;
+	long ret = 0;
+
+	switch (cmd) {
+	case HSC_RESET:
+		hsi_flush(channel->cl);
+		break;
+	case HSC_SET_PM:
+		if (copy_from_user(&state, (void __user *)arg, sizeof(state)))
+			return -EFAULT;
+		if (state == HSC_PM_DISABLE) {
+			if (test_and_set_bit(HSC_CH_WLINE, &channel->flags))
+				return -EINVAL;
+			ret = hsi_start_tx(channel->cl);
+		} else if (state == HSC_PM_ENABLE) {
+			if (!test_and_clear_bit(HSC_CH_WLINE, &channel->flags))
+				return -EINVAL;
+			ret = hsi_stop_tx(channel->cl);
+		} else {
+			ret = -EINVAL;
+		}
+		break;
+	case HSC_SEND_BREAK:
+		return hsc_break_send(channel->cl);
+	case HSC_SET_RX:
+		if (copy_from_user(&rxc, (void __user *)arg, sizeof(rxc)))
+			return -EFAULT;
+		return hsc_rx_set(channel->cl, &rxc);
+	case HSC_GET_RX:
+		hsc_rx_get(channel->cl, &rxc);
+		if (copy_to_user((void __user *)arg, &rxc, sizeof(rxc)))
+			return -EFAULT;
+		break;
+	case HSC_SET_TX:
+		if (copy_from_user(&txc, (void __user *)arg, sizeof(txc)))
+			return -EFAULT;
+		return hsc_tx_set(channel->cl, &txc);
+	case HSC_GET_TX:
+		hsc_tx_get(channel->cl, &txc);
+		if (copy_to_user((void __user *)arg, &txc, sizeof(txc)))
+			return -EFAULT;
+		break;
+	default:
+		return -ENOIOCTLCMD;
+	}
+
+	return ret;
+}
+
+static inline void __hsc_port_release(struct hsc_client_data *cl_data)
+{
+	BUG_ON(cl_data->usecnt == 0);
+
+	if (--cl_data->usecnt == 0) {
+		hsi_flush(cl_data->cl);
+		hsi_release_port(cl_data->cl);
+	}
+}
+
+static int hsc_open(struct inode *inode, struct file *file)
+{
+	struct hsc_client_data *cl_data;
+	struct hsc_channel *channel;
+	int ret = 0;
+
+	pr_debug("open, minor = %d\n", iminor(inode));
+
+	cl_data = container_of(inode->i_cdev, struct hsc_client_data, cdev);
+	mutex_lock(&cl_data->lock);
+	channel = cl_data->channels + (iminor(inode) & HSC_CH_MASK);
+
+	if (test_and_set_bit(HSC_CH_OPEN, &channel->flags)) {
+		ret = -EBUSY;
+		goto out;
+	}
+	/*
+	 * Check if we have already claimed the port associated to the HSI
+	 * client. If not then try to claim it, else increase its refcount
+	 */
+	if (cl_data->usecnt == 0) {
+		ret = hsi_claim_port(cl_data->cl, 0);
+		if (ret < 0)
+			goto out;
+		hsi_setup(cl_data->cl);
+	}
+	cl_data->usecnt++;
+
+	ret = hsc_msgs_alloc(channel);
+	if (ret < 0) {
+		__hsc_port_release(cl_data);
+		goto out;
+	}
+
+	file->private_data = channel;
+	mutex_unlock(&cl_data->lock);
+
+	return ret;
+out:
+	mutex_unlock(&cl_data->lock);
+
+	return ret;
+}
+
+static int hsc_release(struct inode *inode __maybe_unused, struct file *file)
+{
+	struct hsc_channel *channel = file->private_data;
+	struct hsc_client_data *cl_data = channel->cl_data;
+
+	mutex_lock(&cl_data->lock);
+	file->private_data = NULL;
+	if (test_and_clear_bit(HSC_CH_WLINE, &channel->flags))
+		hsi_stop_tx(channel->cl);
+	__hsc_port_release(cl_data);
+	hsc_reset_list(channel, &channel->rx_msgs_queue);
+	hsc_reset_list(channel, &channel->tx_msgs_queue);
+	hsc_reset_list(channel, &channel->free_msgs_list);
+	clear_bit(HSC_CH_READ, &channel->flags);
+	clear_bit(HSC_CH_WRITE, &channel->flags);
+	clear_bit(HSC_CH_OPEN, &channel->flags);
+	wake_up(&channel->rx_wait);
+	wake_up(&channel->tx_wait);
+	mutex_unlock(&cl_data->lock);
+
+	return 0;
+}
+
+static const struct file_operations hsc_fops = {
+	.owner		= THIS_MODULE,
+	.read		= hsc_read,
+	.write		= hsc_write,
+	.unlocked_ioctl	= hsc_ioctl,
+	.open		= hsc_open,
+	.release	= hsc_release,
+};
+
+static void hsc_channel_init(struct hsc_channel *channel)
+{
+	init_waitqueue_head(&channel->rx_wait);
+	init_waitqueue_head(&channel->tx_wait);
+	spin_lock_init(&channel->lock);
+	INIT_LIST_HEAD(&channel->free_msgs_list);
+	INIT_LIST_HEAD(&channel->rx_msgs_queue);
+	INIT_LIST_HEAD(&channel->tx_msgs_queue);
+}
+
+static int hsc_probe(struct device *dev)
+{
+	const char devname[] = "hsi_char";
+	struct hsc_client_data *cl_data;
+	struct hsc_channel *channel;
+	struct hsi_client *cl = to_hsi_client(dev);
+	unsigned int hsc_baseminor;
+	dev_t hsc_dev;
+	int ret;
+	int i;
+
+	cl_data = kzalloc(sizeof(*cl_data), GFP_KERNEL);
+	if (!cl_data)
+		return -ENOMEM;
+
+	hsc_baseminor = HSC_BASEMINOR(hsi_id(cl), hsi_port_id(cl));
+	if (!hsc_major) {
+		ret = alloc_chrdev_region(&hsc_dev, hsc_baseminor,
+						HSC_DEVS, devname);
+		if (ret == 0)
+			hsc_major = MAJOR(hsc_dev);
+	} else {
+		hsc_dev = MKDEV(hsc_major, hsc_baseminor);
+		ret = register_chrdev_region(hsc_dev, HSC_DEVS, devname);
+	}
+	if (ret < 0) {
+		dev_err(dev, "Device %s allocation failed %d\n",
+					hsc_major ? "minor" : "major", ret);
+		goto out1;
+	}
+	mutex_init(&cl_data->lock);
+	hsi_client_set_drvdata(cl, cl_data);
+	cdev_init(&cl_data->cdev, &hsc_fops);
+	cl_data->cdev.owner = THIS_MODULE;
+	cl_data->cl = cl;
+	for (i = 0, channel = cl_data->channels; i < HSC_DEVS; i++, channel++) {
+		hsc_channel_init(channel);
+		channel->ch = i;
+		channel->cl = cl;
+		channel->cl_data = cl_data;
+	}
+
+	/* 1 hsi client -> N char devices (one for each channel) */
+	ret = cdev_add(&cl_data->cdev, hsc_dev, HSC_DEVS);
+	if (ret) {
+		dev_err(dev, "Could not add char device %d\n", ret);
+		goto out2;
+	}
+
+	return 0;
+out2:
+	unregister_chrdev_region(hsc_dev, HSC_DEVS);
+out1:
+	kfree(cl_data);
+
+	return ret;
+}
+
+static int hsc_remove(struct device *dev)
+{
+	struct hsi_client *cl = to_hsi_client(dev);
+	struct hsc_client_data *cl_data = hsi_client_drvdata(cl);
+	dev_t hsc_dev = cl_data->cdev.dev;
+
+	cdev_del(&cl_data->cdev);
+	unregister_chrdev_region(hsc_dev, HSC_DEVS);
+	hsi_client_set_drvdata(cl, NULL);
+	kfree(cl_data);
+
+	return 0;
+}
+
+static struct hsi_client_driver hsc_driver = {
+	.driver = {
+		.name	= "hsi_char",
+		.owner	= THIS_MODULE,
+		.probe	= hsc_probe,
+		.remove	= hsc_remove,
+	},
+};
+
+static int __init hsc_init(void)
+{
+	int ret;
+
+	if ((max_data_size < 4) || (max_data_size > 0x10000) ||
+		(max_data_size & (max_data_size - 1))) {
+		pr_err("Invalid max read/write data size\n");
+		return -EINVAL;
+	}
+
+	ret = hsi_register_client_driver(&hsc_driver);
+	if (ret) {
+		pr_err("Error while registering HSI/SSI driver %d\n", ret);
+		return ret;
+	}
+
+	pr_info("HSI/SSI char device loaded\n");
+
+	return 0;
+}
+module_init(hsc_init);
+
+static void __exit hsc_exit(void)
+{
+	hsi_unregister_client_driver(&hsc_driver);
+	pr_info("HSI char device removed\n");
+}
+module_exit(hsc_exit);
+
+MODULE_AUTHOR("Andras Domokos <andras.domokos@nokia.com>");
+MODULE_ALIAS("hsi:hsi_char");
+MODULE_DESCRIPTION("HSI character device");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/hsi/clients/nokia-modem.c b/drivers/hsi/clients/nokia-modem.c
new file mode 100644
index 000000000..cd7ebf4c2
--- /dev/null
+++ b/drivers/hsi/clients/nokia-modem.c
@@ -0,0 +1,300 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * nokia-modem.c
+ *
+ * HSI client driver for Nokia N900 modem.
+ *
+ * Copyright (C) 2014 Sebastian Reichel <sre@kernel.org>
+ */
+
+#include <linux/gpio/consumer.h>
+#include <linux/hsi/hsi.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_gpio.h>
+#include <linux/hsi/ssi_protocol.h>
+
+static unsigned int pm = 1;
+module_param(pm, int, 0400);
+MODULE_PARM_DESC(pm,
+	"Enable power management (0=disabled, 1=userland based [default])");
+
+struct nokia_modem_gpio {
+	struct gpio_desc	*gpio;
+	const char		*name;
+};
+
+struct nokia_modem_device {
+	struct tasklet_struct	nokia_modem_rst_ind_tasklet;
+	int			nokia_modem_rst_ind_irq;
+	struct device		*device;
+	struct nokia_modem_gpio	*gpios;
+	int			gpio_amount;
+	struct hsi_client	*ssi_protocol;
+	struct hsi_client	*cmt_speech;
+};
+
+static void do_nokia_modem_rst_ind_tasklet(unsigned long data)
+{
+	struct nokia_modem_device *modem = (struct nokia_modem_device *)data;
+
+	if (!modem)
+		return;
+
+	dev_info(modem->device, "CMT rst line change detected\n");
+
+	if (modem->ssi_protocol)
+		ssip_reset_event(modem->ssi_protocol);
+}
+
+static irqreturn_t nokia_modem_rst_ind_isr(int irq, void *data)
+{
+	struct nokia_modem_device *modem = (struct nokia_modem_device *)data;
+
+	tasklet_schedule(&modem->nokia_modem_rst_ind_tasklet);
+
+	return IRQ_HANDLED;
+}
+
+static void nokia_modem_gpio_unexport(struct device *dev)
+{
+	struct nokia_modem_device *modem = dev_get_drvdata(dev);
+	int i;
+
+	for (i = 0; i < modem->gpio_amount; i++) {
+		sysfs_remove_link(&dev->kobj, modem->gpios[i].name);
+		gpiod_unexport(modem->gpios[i].gpio);
+	}
+}
+
+static int nokia_modem_gpio_probe(struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	struct nokia_modem_device *modem = dev_get_drvdata(dev);
+	int gpio_count, gpio_name_count, i, err;
+
+	gpio_count = of_gpio_count(np);
+
+	if (gpio_count < 0) {
+		dev_err(dev, "missing gpios: %d\n", gpio_count);
+		return gpio_count;
+	}
+
+	gpio_name_count = of_property_count_strings(np, "gpio-names");
+
+	if (gpio_count != gpio_name_count) {
+		dev_err(dev, "number of gpios does not equal number of gpio names\n");
+		return -EINVAL;
+	}
+
+	modem->gpios = devm_kcalloc(dev, gpio_count, sizeof(*modem->gpios),
+				    GFP_KERNEL);
+	if (!modem->gpios)
+		return -ENOMEM;
+
+	modem->gpio_amount = gpio_count;
+
+	for (i = 0; i < gpio_count; i++) {
+		modem->gpios[i].gpio = devm_gpiod_get_index(dev, NULL, i,
+							    GPIOD_OUT_LOW);
+		if (IS_ERR(modem->gpios[i].gpio)) {
+			dev_err(dev, "Could not get gpio %d\n", i);
+			return PTR_ERR(modem->gpios[i].gpio);
+		}
+
+		err = of_property_read_string_index(np, "gpio-names", i,
+						&(modem->gpios[i].name));
+		if (err) {
+			dev_err(dev, "Could not get gpio name %d\n", i);
+			return err;
+		}
+
+		err = gpiod_export(modem->gpios[i].gpio, 0);
+		if (err)
+			return err;
+
+		err = gpiod_export_link(dev, modem->gpios[i].name,
+							modem->gpios[i].gpio);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int nokia_modem_probe(struct device *dev)
+{
+	struct device_node *np;
+	struct nokia_modem_device *modem;
+	struct hsi_client *cl = to_hsi_client(dev);
+	struct hsi_port *port = hsi_get_port(cl);
+	int irq, pflags, err;
+	struct hsi_board_info ssip;
+	struct hsi_board_info cmtspeech;
+
+	np = dev->of_node;
+	if (!np) {
+		dev_err(dev, "device tree node not found\n");
+		return -ENXIO;
+	}
+
+	modem = devm_kzalloc(dev, sizeof(*modem), GFP_KERNEL);
+	if (!modem)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, modem);
+	modem->device = dev;
+
+	irq = irq_of_parse_and_map(np, 0);
+	if (!irq) {
+		dev_err(dev, "Invalid rst_ind interrupt (%d)\n", irq);
+		return -EINVAL;
+	}
+	modem->nokia_modem_rst_ind_irq = irq;
+	pflags = irq_get_trigger_type(irq);
+
+	tasklet_init(&modem->nokia_modem_rst_ind_tasklet,
+			do_nokia_modem_rst_ind_tasklet, (unsigned long)modem);
+	err = devm_request_irq(dev, irq, nokia_modem_rst_ind_isr,
+				pflags, "modem_rst_ind", modem);
+	if (err < 0) {
+		dev_err(dev, "Request rst_ind irq(%d) failed (flags %d)\n",
+								irq, pflags);
+		return err;
+	}
+	enable_irq_wake(irq);
+
+	if (pm) {
+		err = nokia_modem_gpio_probe(dev);
+		if (err < 0) {
+			dev_err(dev, "Could not probe GPIOs\n");
+			goto error1;
+		}
+	}
+
+	ssip.name = "ssi-protocol";
+	ssip.tx_cfg = cl->tx_cfg;
+	ssip.rx_cfg = cl->rx_cfg;
+	ssip.platform_data = NULL;
+	ssip.archdata = NULL;
+
+	modem->ssi_protocol = hsi_new_client(port, &ssip);
+	if (!modem->ssi_protocol) {
+		dev_err(dev, "Could not register ssi-protocol device\n");
+		err = -ENOMEM;
+		goto error2;
+	}
+
+	err = device_attach(&modem->ssi_protocol->device);
+	if (err == 0) {
+		dev_dbg(dev, "Missing ssi-protocol driver\n");
+		err = -EPROBE_DEFER;
+		goto error3;
+	} else if (err < 0) {
+		dev_err(dev, "Could not load ssi-protocol driver (%d)\n", err);
+		goto error3;
+	}
+
+	cmtspeech.name = "cmt-speech";
+	cmtspeech.tx_cfg = cl->tx_cfg;
+	cmtspeech.rx_cfg = cl->rx_cfg;
+	cmtspeech.platform_data = NULL;
+	cmtspeech.archdata = NULL;
+
+	modem->cmt_speech = hsi_new_client(port, &cmtspeech);
+	if (!modem->cmt_speech) {
+		dev_err(dev, "Could not register cmt-speech device\n");
+		err = -ENOMEM;
+		goto error3;
+	}
+
+	err = device_attach(&modem->cmt_speech->device);
+	if (err == 0) {
+		dev_dbg(dev, "Missing cmt-speech driver\n");
+		err = -EPROBE_DEFER;
+		goto error4;
+	} else if (err < 0) {
+		dev_err(dev, "Could not load cmt-speech driver (%d)\n", err);
+		goto error4;
+	}
+
+	dev_info(dev, "Registered Nokia HSI modem\n");
+
+	return 0;
+
+error4:
+	hsi_remove_client(&modem->cmt_speech->device, NULL);
+error3:
+	hsi_remove_client(&modem->ssi_protocol->device, NULL);
+error2:
+	nokia_modem_gpio_unexport(dev);
+error1:
+	disable_irq_wake(modem->nokia_modem_rst_ind_irq);
+	tasklet_kill(&modem->nokia_modem_rst_ind_tasklet);
+
+	return err;
+}
+
+static int nokia_modem_remove(struct device *dev)
+{
+	struct nokia_modem_device *modem = dev_get_drvdata(dev);
+
+	if (!modem)
+		return 0;
+
+	if (modem->cmt_speech) {
+		hsi_remove_client(&modem->cmt_speech->device, NULL);
+		modem->cmt_speech = NULL;
+	}
+
+	if (modem->ssi_protocol) {
+		hsi_remove_client(&modem->ssi_protocol->device, NULL);
+		modem->ssi_protocol = NULL;
+	}
+
+	nokia_modem_gpio_unexport(dev);
+	dev_set_drvdata(dev, NULL);
+	disable_irq_wake(modem->nokia_modem_rst_ind_irq);
+	tasklet_kill(&modem->nokia_modem_rst_ind_tasklet);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id nokia_modem_of_match[] = {
+	{ .compatible = "nokia,n900-modem", },
+	{ .compatible = "nokia,n950-modem", },
+	{ .compatible = "nokia,n9-modem", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, nokia_modem_of_match);
+#endif
+
+static struct hsi_client_driver nokia_modem_driver = {
+	.driver = {
+		.name	= "nokia-modem",
+		.owner	= THIS_MODULE,
+		.probe	= nokia_modem_probe,
+		.remove	= nokia_modem_remove,
+		.of_match_table = of_match_ptr(nokia_modem_of_match),
+	},
+};
+
+static int __init nokia_modem_init(void)
+{
+	return hsi_register_client_driver(&nokia_modem_driver);
+}
+module_init(nokia_modem_init);
+
+static void __exit nokia_modem_exit(void)
+{
+	hsi_unregister_client_driver(&nokia_modem_driver);
+}
+module_exit(nokia_modem_exit);
+
+MODULE_ALIAS("hsi:nokia-modem");
+MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
+MODULE_DESCRIPTION("HSI driver module for Nokia N900 Modem");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hsi/clients/ssi_protocol.c b/drivers/hsi/clients/ssi_protocol.c
new file mode 100644
index 000000000..96d0eccca
--- /dev/null
+++ b/drivers/hsi/clients/ssi_protocol.c
@@ -0,0 +1,1191 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ssi_protocol.c
+ *
+ * Implementation of the SSI McSAAB improved protocol.
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ * Copyright (C) 2013 Sebastian Reichel <sre@kernel.org>
+ *
+ * Contact: Carlos Chinea <carlos.chinea@nokia.com>
+ */
+
+#include <linux/atomic.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/if_ether.h>
+#include <linux/if_arp.h>
+#include <linux/if_phonet.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/notifier.h>
+#include <linux/scatterlist.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+#include <linux/hsi/hsi.h>
+#include <linux/hsi/ssi_protocol.h>
+
+void ssi_waketest(struct hsi_client *cl, unsigned int enable);
+
+#define SSIP_TXQUEUE_LEN	100
+#define SSIP_MAX_MTU		65535
+#define SSIP_DEFAULT_MTU	4000
+#define PN_MEDIA_SOS		21
+#define SSIP_MIN_PN_HDR		6	/* FIXME: Revisit */
+#define SSIP_WDTOUT		2000	/* FIXME: has to be 500 msecs */
+#define SSIP_KATOUT		15	/* 15 msecs */
+#define SSIP_MAX_CMDS		5 /* Number of pre-allocated commands buffers */
+#define SSIP_BYTES_TO_FRAMES(x) ((((x) - 1) >> 2) + 1)
+#define SSIP_CMT_LOADER_SYNC	0x11223344
+/*
+ * SSI protocol command definitions
+ */
+#define SSIP_COMMAND(data)	((data) >> 28)
+#define SSIP_PAYLOAD(data)	((data) & 0xfffffff)
+/* Commands */
+#define SSIP_SW_BREAK		0
+#define SSIP_BOOTINFO_REQ	1
+#define SSIP_BOOTINFO_RESP	2
+#define SSIP_WAKETEST_RESULT	3
+#define SSIP_START_TRANS	4
+#define SSIP_READY		5
+/* Payloads */
+#define SSIP_DATA_VERSION(data)	((data) & 0xff)
+#define SSIP_LOCAL_VERID	1
+#define SSIP_WAKETEST_OK	0
+#define SSIP_WAKETEST_FAILED	1
+#define SSIP_PDU_LENGTH(data)	(((data) >> 8) & 0xffff)
+#define SSIP_MSG_ID(data)	((data) & 0xff)
+/* Generic Command */
+#define SSIP_CMD(cmd, payload)	(((cmd) << 28) | ((payload) & 0xfffffff))
+/* Commands for the control channel */
+#define SSIP_BOOTINFO_REQ_CMD(ver) \
+		SSIP_CMD(SSIP_BOOTINFO_REQ, SSIP_DATA_VERSION(ver))
+#define SSIP_BOOTINFO_RESP_CMD(ver) \
+		SSIP_CMD(SSIP_BOOTINFO_RESP, SSIP_DATA_VERSION(ver))
+#define SSIP_START_TRANS_CMD(pdulen, id) \
+		SSIP_CMD(SSIP_START_TRANS, (((pdulen) << 8) | SSIP_MSG_ID(id)))
+#define SSIP_READY_CMD		SSIP_CMD(SSIP_READY, 0)
+#define SSIP_SWBREAK_CMD	SSIP_CMD(SSIP_SW_BREAK, 0)
+
+#define SSIP_WAKETEST_FLAG 0
+
+/* Main state machine states */
+enum {
+	INIT,
+	HANDSHAKE,
+	ACTIVE,
+};
+
+/* Send state machine states */
+enum {
+	SEND_IDLE,
+	WAIT4READY,
+	SEND_READY,
+	SENDING,
+	SENDING_SWBREAK,
+};
+
+/* Receive state machine states */
+enum {
+	RECV_IDLE,
+	RECV_READY,
+	RECEIVING,
+};
+
+/**
+ * struct ssi_protocol - SSI protocol (McSAAB) data
+ * @main_state: Main state machine
+ * @send_state: TX state machine
+ * @recv_state: RX state machine
+ * @flags: Flags, currently only used to follow wake line test
+ * @rxid: RX data id
+ * @txid: TX data id
+ * @txqueue_len: TX queue length
+ * @tx_wd: TX watchdog
+ * @rx_wd: RX watchdog
+ * @keep_alive: Workaround for SSI HW bug
+ * @lock: To serialize access to this struct
+ * @netdev: Phonet network device
+ * @txqueue: TX data queue
+ * @cmdqueue: Queue of free commands
+ * @cl: HSI client own reference
+ * @link: Link for ssip_list
+ * @tx_usecount: Refcount to keep track the slaves that use the wake line
+ * @channel_id_cmd: HSI channel id for command stream
+ * @channel_id_data: HSI channel id for data stream
+ */
+struct ssi_protocol {
+	unsigned int		main_state;
+	unsigned int		send_state;
+	unsigned int		recv_state;
+	unsigned long		flags;
+	u8			rxid;
+	u8			txid;
+	unsigned int		txqueue_len;
+	struct timer_list	tx_wd;
+	struct timer_list	rx_wd;
+	struct timer_list	keep_alive; /* wake-up workaround */
+	spinlock_t		lock;
+	struct net_device	*netdev;
+	struct list_head	txqueue;
+	struct list_head	cmdqueue;
+	struct work_struct	work;
+	struct hsi_client	*cl;
+	struct list_head	link;
+	atomic_t		tx_usecnt;
+	int			channel_id_cmd;
+	int			channel_id_data;
+};
+
+/* List of ssi protocol instances */
+static LIST_HEAD(ssip_list);
+
+static void ssip_rxcmd_complete(struct hsi_msg *msg);
+
+static inline void ssip_set_cmd(struct hsi_msg *msg, u32 cmd)
+{
+	u32 *data;
+
+	data = sg_virt(msg->sgt.sgl);
+	*data = cmd;
+}
+
+static inline u32 ssip_get_cmd(struct hsi_msg *msg)
+{
+	u32 *data;
+
+	data = sg_virt(msg->sgt.sgl);
+
+	return *data;
+}
+
+static void ssip_skb_to_msg(struct sk_buff *skb, struct hsi_msg *msg)
+{
+	skb_frag_t *frag;
+	struct scatterlist *sg;
+	int i;
+
+	BUG_ON(msg->sgt.nents != (unsigned int)(skb_shinfo(skb)->nr_frags + 1));
+
+	sg = msg->sgt.sgl;
+	sg_set_buf(sg, skb->data, skb_headlen(skb));
+	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+		sg = sg_next(sg);
+		BUG_ON(!sg);
+		frag = &skb_shinfo(skb)->frags[i];
+		sg_set_page(sg, skb_frag_page(frag), skb_frag_size(frag),
+				skb_frag_off(frag));
+	}
+}
+
+static void ssip_free_data(struct hsi_msg *msg)
+{
+	struct sk_buff *skb;
+
+	skb = msg->context;
+	pr_debug("free data: msg %p context %p skb %p\n", msg, msg->context,
+								skb);
+	msg->destructor = NULL;
+	dev_kfree_skb(skb);
+	hsi_free_msg(msg);
+}
+
+static struct hsi_msg *ssip_alloc_data(struct ssi_protocol *ssi,
+					struct sk_buff *skb, gfp_t flags)
+{
+	struct hsi_msg *msg;
+
+	msg = hsi_alloc_msg(skb_shinfo(skb)->nr_frags + 1, flags);
+	if (!msg)
+		return NULL;
+	ssip_skb_to_msg(skb, msg);
+	msg->destructor = ssip_free_data;
+	msg->channel = ssi->channel_id_data;
+	msg->context = skb;
+
+	return msg;
+}
+
+static inline void ssip_release_cmd(struct hsi_msg *msg)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(msg->cl);
+
+	dev_dbg(&msg->cl->device, "Release cmd 0x%08x\n", ssip_get_cmd(msg));
+	spin_lock_bh(&ssi->lock);
+	list_add_tail(&msg->link, &ssi->cmdqueue);
+	spin_unlock_bh(&ssi->lock);
+}
+
+static struct hsi_msg *ssip_claim_cmd(struct ssi_protocol *ssi)
+{
+	struct hsi_msg *msg;
+
+	BUG_ON(list_empty(&ssi->cmdqueue));
+
+	spin_lock_bh(&ssi->lock);
+	msg = list_first_entry(&ssi->cmdqueue, struct hsi_msg, link);
+	list_del(&msg->link);
+	spin_unlock_bh(&ssi->lock);
+	msg->destructor = ssip_release_cmd;
+
+	return msg;
+}
+
+static void ssip_free_cmds(struct ssi_protocol *ssi)
+{
+	struct hsi_msg *msg, *tmp;
+
+	list_for_each_entry_safe(msg, tmp, &ssi->cmdqueue, link) {
+		list_del(&msg->link);
+		msg->destructor = NULL;
+		kfree(sg_virt(msg->sgt.sgl));
+		hsi_free_msg(msg);
+	}
+}
+
+static int ssip_alloc_cmds(struct ssi_protocol *ssi)
+{
+	struct hsi_msg *msg;
+	u32 *buf;
+	unsigned int i;
+
+	for (i = 0; i < SSIP_MAX_CMDS; i++) {
+		msg = hsi_alloc_msg(1, GFP_KERNEL);
+		if (!msg)
+			goto out;
+		buf = kmalloc(sizeof(*buf), GFP_KERNEL);
+		if (!buf) {
+			hsi_free_msg(msg);
+			goto out;
+		}
+		sg_init_one(msg->sgt.sgl, buf, sizeof(*buf));
+		msg->channel = ssi->channel_id_cmd;
+		list_add_tail(&msg->link, &ssi->cmdqueue);
+	}
+
+	return 0;
+out:
+	ssip_free_cmds(ssi);
+
+	return -ENOMEM;
+}
+
+static void ssip_set_rxstate(struct ssi_protocol *ssi, unsigned int state)
+{
+	ssi->recv_state = state;
+	switch (state) {
+	case RECV_IDLE:
+		del_timer(&ssi->rx_wd);
+		if (ssi->send_state == SEND_IDLE)
+			del_timer(&ssi->keep_alive);
+		break;
+	case RECV_READY:
+		/* CMT speech workaround */
+		if (atomic_read(&ssi->tx_usecnt))
+			break;
+		fallthrough;
+	case RECEIVING:
+		mod_timer(&ssi->keep_alive, jiffies +
+						msecs_to_jiffies(SSIP_KATOUT));
+		mod_timer(&ssi->rx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
+		break;
+	default:
+		break;
+	}
+}
+
+static void ssip_set_txstate(struct ssi_protocol *ssi, unsigned int state)
+{
+	ssi->send_state = state;
+	switch (state) {
+	case SEND_IDLE:
+	case SEND_READY:
+		del_timer(&ssi->tx_wd);
+		if (ssi->recv_state == RECV_IDLE)
+			del_timer(&ssi->keep_alive);
+		break;
+	case WAIT4READY:
+	case SENDING:
+	case SENDING_SWBREAK:
+		mod_timer(&ssi->keep_alive,
+				jiffies + msecs_to_jiffies(SSIP_KATOUT));
+		mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
+		break;
+	default:
+		break;
+	}
+}
+
+struct hsi_client *ssip_slave_get_master(struct hsi_client *slave)
+{
+	struct hsi_client *master = ERR_PTR(-ENODEV);
+	struct ssi_protocol *ssi;
+
+	list_for_each_entry(ssi, &ssip_list, link)
+		if (slave->device.parent == ssi->cl->device.parent) {
+			master = ssi->cl;
+			break;
+		}
+
+	return master;
+}
+EXPORT_SYMBOL_GPL(ssip_slave_get_master);
+
+int ssip_slave_start_tx(struct hsi_client *master)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(master);
+
+	dev_dbg(&master->device, "start TX %d\n", atomic_read(&ssi->tx_usecnt));
+	spin_lock_bh(&ssi->lock);
+	if (ssi->send_state == SEND_IDLE) {
+		ssip_set_txstate(ssi, WAIT4READY);
+		hsi_start_tx(master);
+	}
+	spin_unlock_bh(&ssi->lock);
+	atomic_inc(&ssi->tx_usecnt);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ssip_slave_start_tx);
+
+int ssip_slave_stop_tx(struct hsi_client *master)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(master);
+
+	WARN_ON_ONCE(atomic_read(&ssi->tx_usecnt) == 0);
+
+	if (atomic_dec_and_test(&ssi->tx_usecnt)) {
+		spin_lock_bh(&ssi->lock);
+		if ((ssi->send_state == SEND_READY) ||
+			(ssi->send_state == WAIT4READY)) {
+			ssip_set_txstate(ssi, SEND_IDLE);
+			hsi_stop_tx(master);
+		}
+		spin_unlock_bh(&ssi->lock);
+	}
+	dev_dbg(&master->device, "stop TX %d\n", atomic_read(&ssi->tx_usecnt));
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ssip_slave_stop_tx);
+
+int ssip_slave_running(struct hsi_client *master)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(master);
+	return netif_running(ssi->netdev);
+}
+EXPORT_SYMBOL_GPL(ssip_slave_running);
+
+static void ssip_reset(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct list_head *head, *tmp;
+	struct hsi_msg *msg;
+
+	if (netif_running(ssi->netdev))
+		netif_carrier_off(ssi->netdev);
+	hsi_flush(cl);
+	spin_lock_bh(&ssi->lock);
+	if (ssi->send_state != SEND_IDLE)
+		hsi_stop_tx(cl);
+	spin_unlock_bh(&ssi->lock);
+	if (test_and_clear_bit(SSIP_WAKETEST_FLAG, &ssi->flags))
+		ssi_waketest(cl, 0); /* FIXME: To be removed */
+	spin_lock_bh(&ssi->lock);
+	del_timer(&ssi->rx_wd);
+	del_timer(&ssi->tx_wd);
+	del_timer(&ssi->keep_alive);
+	ssi->main_state = 0;
+	ssi->send_state = 0;
+	ssi->recv_state = 0;
+	ssi->flags = 0;
+	ssi->rxid = 0;
+	ssi->txid = 0;
+	list_for_each_safe(head, tmp, &ssi->txqueue) {
+		msg = list_entry(head, struct hsi_msg, link);
+		dev_dbg(&cl->device, "Pending TX data\n");
+		list_del(head);
+		ssip_free_data(msg);
+	}
+	ssi->txqueue_len = 0;
+	spin_unlock_bh(&ssi->lock);
+}
+
+static void ssip_dump_state(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *msg;
+
+	spin_lock_bh(&ssi->lock);
+	dev_err(&cl->device, "Main state: %d\n", ssi->main_state);
+	dev_err(&cl->device, "Recv state: %d\n", ssi->recv_state);
+	dev_err(&cl->device, "Send state: %d\n", ssi->send_state);
+	dev_err(&cl->device, "CMT %s\n", (ssi->main_state == ACTIVE) ?
+							"Online" : "Offline");
+	dev_err(&cl->device, "Wake test %d\n",
+				test_bit(SSIP_WAKETEST_FLAG, &ssi->flags));
+	dev_err(&cl->device, "Data RX id: %d\n", ssi->rxid);
+	dev_err(&cl->device, "Data TX id: %d\n", ssi->txid);
+
+	list_for_each_entry(msg, &ssi->txqueue, link)
+		dev_err(&cl->device, "pending TX data (%p)\n", msg);
+	spin_unlock_bh(&ssi->lock);
+}
+
+static void ssip_error(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *msg;
+
+	ssip_dump_state(cl);
+	ssip_reset(cl);
+	msg = ssip_claim_cmd(ssi);
+	msg->complete = ssip_rxcmd_complete;
+	hsi_async_read(cl, msg);
+}
+
+static void ssip_keep_alive(struct timer_list *t)
+{
+	struct ssi_protocol *ssi = from_timer(ssi, t, keep_alive);
+	struct hsi_client *cl = ssi->cl;
+
+	dev_dbg(&cl->device, "Keep alive kick in: m(%d) r(%d) s(%d)\n",
+		ssi->main_state, ssi->recv_state, ssi->send_state);
+
+	spin_lock(&ssi->lock);
+	if (ssi->recv_state == RECV_IDLE)
+		switch (ssi->send_state) {
+		case SEND_READY:
+			if (atomic_read(&ssi->tx_usecnt) == 0)
+				break;
+			fallthrough;
+			/*
+			 * Workaround for cmt-speech in that case
+			 * we relay on audio timers.
+			 */
+		case SEND_IDLE:
+			spin_unlock(&ssi->lock);
+			return;
+		}
+	mod_timer(&ssi->keep_alive, jiffies + msecs_to_jiffies(SSIP_KATOUT));
+	spin_unlock(&ssi->lock);
+}
+
+static void ssip_rx_wd(struct timer_list *t)
+{
+	struct ssi_protocol *ssi = from_timer(ssi, t, rx_wd);
+	struct hsi_client *cl = ssi->cl;
+
+	dev_err(&cl->device, "Watchdog triggered\n");
+	ssip_error(cl);
+}
+
+static void ssip_tx_wd(struct timer_list *t)
+{
+	struct ssi_protocol *ssi = from_timer(ssi, t, tx_wd);
+	struct hsi_client *cl = ssi->cl;
+
+	dev_err(&cl->device, "Watchdog triggered\n");
+	ssip_error(cl);
+}
+
+static void ssip_send_bootinfo_req_cmd(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *msg;
+
+	dev_dbg(&cl->device, "Issuing BOOT INFO REQ command\n");
+	msg = ssip_claim_cmd(ssi);
+	ssip_set_cmd(msg, SSIP_BOOTINFO_REQ_CMD(SSIP_LOCAL_VERID));
+	msg->complete = ssip_release_cmd;
+	hsi_async_write(cl, msg);
+	dev_dbg(&cl->device, "Issuing RX command\n");
+	msg = ssip_claim_cmd(ssi);
+	msg->complete = ssip_rxcmd_complete;
+	hsi_async_read(cl, msg);
+}
+
+static void ssip_start_rx(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *msg;
+
+	dev_dbg(&cl->device, "RX start M(%d) R(%d)\n", ssi->main_state,
+						ssi->recv_state);
+	spin_lock_bh(&ssi->lock);
+	/*
+	 * We can have two UP events in a row due to a short low
+	 * high transition. Therefore we need to ignore the sencond UP event.
+	 */
+	if ((ssi->main_state != ACTIVE) || (ssi->recv_state == RECV_READY)) {
+		spin_unlock_bh(&ssi->lock);
+		return;
+	}
+	ssip_set_rxstate(ssi, RECV_READY);
+	spin_unlock_bh(&ssi->lock);
+
+	msg = ssip_claim_cmd(ssi);
+	ssip_set_cmd(msg, SSIP_READY_CMD);
+	msg->complete = ssip_release_cmd;
+	dev_dbg(&cl->device, "Send READY\n");
+	hsi_async_write(cl, msg);
+}
+
+static void ssip_stop_rx(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+
+	dev_dbg(&cl->device, "RX stop M(%d)\n", ssi->main_state);
+	spin_lock_bh(&ssi->lock);
+	if (likely(ssi->main_state == ACTIVE))
+		ssip_set_rxstate(ssi, RECV_IDLE);
+	spin_unlock_bh(&ssi->lock);
+}
+
+static void ssip_free_strans(struct hsi_msg *msg)
+{
+	ssip_free_data(msg->context);
+	ssip_release_cmd(msg);
+}
+
+static void ssip_strans_complete(struct hsi_msg *msg)
+{
+	struct hsi_client *cl = msg->cl;
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *data;
+
+	data = msg->context;
+	ssip_release_cmd(msg);
+	spin_lock_bh(&ssi->lock);
+	ssip_set_txstate(ssi, SENDING);
+	spin_unlock_bh(&ssi->lock);
+	hsi_async_write(cl, data);
+}
+
+static int ssip_xmit(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *msg, *dmsg;
+	struct sk_buff *skb;
+
+	spin_lock_bh(&ssi->lock);
+	if (list_empty(&ssi->txqueue)) {
+		spin_unlock_bh(&ssi->lock);
+		return 0;
+	}
+	dmsg = list_first_entry(&ssi->txqueue, struct hsi_msg, link);
+	list_del(&dmsg->link);
+	ssi->txqueue_len--;
+	spin_unlock_bh(&ssi->lock);
+
+	msg = ssip_claim_cmd(ssi);
+	skb = dmsg->context;
+	msg->context = dmsg;
+	msg->complete = ssip_strans_complete;
+	msg->destructor = ssip_free_strans;
+
+	spin_lock_bh(&ssi->lock);
+	ssip_set_cmd(msg, SSIP_START_TRANS_CMD(SSIP_BYTES_TO_FRAMES(skb->len),
+								ssi->txid));
+	ssi->txid++;
+	ssip_set_txstate(ssi, SENDING);
+	spin_unlock_bh(&ssi->lock);
+
+	dev_dbg(&cl->device, "Send STRANS (%d frames)\n",
+						SSIP_BYTES_TO_FRAMES(skb->len));
+
+	return hsi_async_write(cl, msg);
+}
+
+/* In soft IRQ context */
+static void ssip_pn_rx(struct sk_buff *skb)
+{
+	struct net_device *dev = skb->dev;
+
+	if (unlikely(!netif_running(dev))) {
+		dev_dbg(&dev->dev, "Drop RX packet\n");
+		dev->stats.rx_dropped++;
+		dev_kfree_skb(skb);
+		return;
+	}
+	if (unlikely(!pskb_may_pull(skb, SSIP_MIN_PN_HDR))) {
+		dev_dbg(&dev->dev, "Error drop RX packet\n");
+		dev->stats.rx_errors++;
+		dev->stats.rx_length_errors++;
+		dev_kfree_skb(skb);
+		return;
+	}
+	dev->stats.rx_packets++;
+	dev->stats.rx_bytes += skb->len;
+
+	/* length field is exchanged in network byte order */
+	((u16 *)skb->data)[2] = ntohs(((u16 *)skb->data)[2]);
+	dev_dbg(&dev->dev, "RX length fixed (%04x -> %u)\n",
+			((u16 *)skb->data)[2], ntohs(((u16 *)skb->data)[2]));
+
+	skb->protocol = htons(ETH_P_PHONET);
+	skb_reset_mac_header(skb);
+	__skb_pull(skb, 1);
+	netif_rx(skb);
+}
+
+static void ssip_rx_data_complete(struct hsi_msg *msg)
+{
+	struct hsi_client *cl = msg->cl;
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct sk_buff *skb;
+
+	if (msg->status == HSI_STATUS_ERROR) {
+		dev_err(&cl->device, "RX data error\n");
+		ssip_free_data(msg);
+		ssip_error(cl);
+		return;
+	}
+	del_timer(&ssi->rx_wd); /* FIXME: Revisit */
+	skb = msg->context;
+	ssip_pn_rx(skb);
+	hsi_free_msg(msg);
+}
+
+static void ssip_rx_bootinforeq(struct hsi_client *cl, u32 cmd)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *msg;
+
+	/* Workaroud: Ignore CMT Loader message leftover */
+	if (cmd == SSIP_CMT_LOADER_SYNC)
+		return;
+
+	switch (ssi->main_state) {
+	case ACTIVE:
+		dev_err(&cl->device, "Boot info req on active state\n");
+		ssip_error(cl);
+		fallthrough;
+	case INIT:
+	case HANDSHAKE:
+		spin_lock_bh(&ssi->lock);
+		ssi->main_state = HANDSHAKE;
+		spin_unlock_bh(&ssi->lock);
+
+		if (!test_and_set_bit(SSIP_WAKETEST_FLAG, &ssi->flags))
+			ssi_waketest(cl, 1); /* FIXME: To be removed */
+
+		spin_lock_bh(&ssi->lock);
+		/* Start boot handshake watchdog */
+		mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
+		spin_unlock_bh(&ssi->lock);
+		dev_dbg(&cl->device, "Send BOOTINFO_RESP\n");
+		if (SSIP_DATA_VERSION(cmd) != SSIP_LOCAL_VERID)
+			dev_warn(&cl->device, "boot info req verid mismatch\n");
+		msg = ssip_claim_cmd(ssi);
+		ssip_set_cmd(msg, SSIP_BOOTINFO_RESP_CMD(SSIP_LOCAL_VERID));
+		msg->complete = ssip_release_cmd;
+		hsi_async_write(cl, msg);
+		break;
+	default:
+		dev_dbg(&cl->device, "Wrong state M(%d)\n", ssi->main_state);
+		break;
+	}
+}
+
+static void ssip_rx_bootinforesp(struct hsi_client *cl, u32 cmd)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+
+	if (SSIP_DATA_VERSION(cmd) != SSIP_LOCAL_VERID)
+		dev_warn(&cl->device, "boot info resp verid mismatch\n");
+
+	spin_lock_bh(&ssi->lock);
+	if (ssi->main_state != ACTIVE)
+		/* Use tx_wd as a boot watchdog in non ACTIVE state */
+		mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
+	else
+		dev_dbg(&cl->device, "boot info resp ignored M(%d)\n",
+							ssi->main_state);
+	spin_unlock_bh(&ssi->lock);
+}
+
+static void ssip_rx_waketest(struct hsi_client *cl, u32 cmd)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	unsigned int wkres = SSIP_PAYLOAD(cmd);
+
+	spin_lock_bh(&ssi->lock);
+	if (ssi->main_state != HANDSHAKE) {
+		dev_dbg(&cl->device, "wake lines test ignored M(%d)\n",
+							ssi->main_state);
+		spin_unlock_bh(&ssi->lock);
+		return;
+	}
+	spin_unlock_bh(&ssi->lock);
+
+	if (test_and_clear_bit(SSIP_WAKETEST_FLAG, &ssi->flags))
+		ssi_waketest(cl, 0); /* FIXME: To be removed */
+
+	spin_lock_bh(&ssi->lock);
+	ssi->main_state = ACTIVE;
+	del_timer(&ssi->tx_wd); /* Stop boot handshake timer */
+	spin_unlock_bh(&ssi->lock);
+
+	dev_notice(&cl->device, "WAKELINES TEST %s\n",
+				wkres & SSIP_WAKETEST_FAILED ? "FAILED" : "OK");
+	if (wkres & SSIP_WAKETEST_FAILED) {
+		ssip_error(cl);
+		return;
+	}
+	dev_dbg(&cl->device, "CMT is ONLINE\n");
+	netif_wake_queue(ssi->netdev);
+	netif_carrier_on(ssi->netdev);
+}
+
+static void ssip_rx_ready(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+
+	spin_lock_bh(&ssi->lock);
+	if (unlikely(ssi->main_state != ACTIVE)) {
+		dev_dbg(&cl->device, "READY on wrong state: S(%d) M(%d)\n",
+					ssi->send_state, ssi->main_state);
+		spin_unlock_bh(&ssi->lock);
+		return;
+	}
+	if (ssi->send_state != WAIT4READY) {
+		dev_dbg(&cl->device, "Ignore spurious READY command\n");
+		spin_unlock_bh(&ssi->lock);
+		return;
+	}
+	ssip_set_txstate(ssi, SEND_READY);
+	spin_unlock_bh(&ssi->lock);
+	ssip_xmit(cl);
+}
+
+static void ssip_rx_strans(struct hsi_client *cl, u32 cmd)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct sk_buff *skb;
+	struct hsi_msg *msg;
+	int len = SSIP_PDU_LENGTH(cmd);
+
+	dev_dbg(&cl->device, "RX strans: %d frames\n", len);
+	spin_lock_bh(&ssi->lock);
+	if (unlikely(ssi->main_state != ACTIVE)) {
+		dev_err(&cl->device, "START TRANS wrong state: S(%d) M(%d)\n",
+					ssi->send_state, ssi->main_state);
+		spin_unlock_bh(&ssi->lock);
+		return;
+	}
+	ssip_set_rxstate(ssi, RECEIVING);
+	if (unlikely(SSIP_MSG_ID(cmd) != ssi->rxid)) {
+		dev_err(&cl->device, "START TRANS id %d expected %d\n",
+					SSIP_MSG_ID(cmd), ssi->rxid);
+		spin_unlock_bh(&ssi->lock);
+		goto out1;
+	}
+	ssi->rxid++;
+	spin_unlock_bh(&ssi->lock);
+	skb = netdev_alloc_skb(ssi->netdev, len * 4);
+	if (unlikely(!skb)) {
+		dev_err(&cl->device, "No memory for rx skb\n");
+		goto out1;
+	}
+	skb->dev = ssi->netdev;
+	skb_put(skb, len * 4);
+	msg = ssip_alloc_data(ssi, skb, GFP_ATOMIC);
+	if (unlikely(!msg)) {
+		dev_err(&cl->device, "No memory for RX data msg\n");
+		goto out2;
+	}
+	msg->complete = ssip_rx_data_complete;
+	hsi_async_read(cl, msg);
+
+	return;
+out2:
+	dev_kfree_skb(skb);
+out1:
+	ssip_error(cl);
+}
+
+static void ssip_rxcmd_complete(struct hsi_msg *msg)
+{
+	struct hsi_client *cl = msg->cl;
+	u32 cmd = ssip_get_cmd(msg);
+	unsigned int cmdid = SSIP_COMMAND(cmd);
+
+	if (msg->status == HSI_STATUS_ERROR) {
+		dev_err(&cl->device, "RX error detected\n");
+		ssip_release_cmd(msg);
+		ssip_error(cl);
+		return;
+	}
+	hsi_async_read(cl, msg);
+	dev_dbg(&cl->device, "RX cmd: 0x%08x\n", cmd);
+	switch (cmdid) {
+	case SSIP_SW_BREAK:
+		/* Ignored */
+		break;
+	case SSIP_BOOTINFO_REQ:
+		ssip_rx_bootinforeq(cl, cmd);
+		break;
+	case SSIP_BOOTINFO_RESP:
+		ssip_rx_bootinforesp(cl, cmd);
+		break;
+	case SSIP_WAKETEST_RESULT:
+		ssip_rx_waketest(cl, cmd);
+		break;
+	case SSIP_START_TRANS:
+		ssip_rx_strans(cl, cmd);
+		break;
+	case SSIP_READY:
+		ssip_rx_ready(cl);
+		break;
+	default:
+		dev_warn(&cl->device, "command 0x%08x not supported\n", cmd);
+		break;
+	}
+}
+
+static void ssip_swbreak_complete(struct hsi_msg *msg)
+{
+	struct hsi_client *cl = msg->cl;
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+
+	ssip_release_cmd(msg);
+	spin_lock_bh(&ssi->lock);
+	if (list_empty(&ssi->txqueue)) {
+		if (atomic_read(&ssi->tx_usecnt)) {
+			ssip_set_txstate(ssi, SEND_READY);
+		} else {
+			ssip_set_txstate(ssi, SEND_IDLE);
+			hsi_stop_tx(cl);
+		}
+		spin_unlock_bh(&ssi->lock);
+	} else {
+		spin_unlock_bh(&ssi->lock);
+		ssip_xmit(cl);
+	}
+	netif_wake_queue(ssi->netdev);
+}
+
+static void ssip_tx_data_complete(struct hsi_msg *msg)
+{
+	struct hsi_client *cl = msg->cl;
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *cmsg;
+
+	if (msg->status == HSI_STATUS_ERROR) {
+		dev_err(&cl->device, "TX data error\n");
+		ssip_error(cl);
+		goto out;
+	}
+	spin_lock_bh(&ssi->lock);
+	if (list_empty(&ssi->txqueue)) {
+		ssip_set_txstate(ssi, SENDING_SWBREAK);
+		spin_unlock_bh(&ssi->lock);
+		cmsg = ssip_claim_cmd(ssi);
+		ssip_set_cmd(cmsg, SSIP_SWBREAK_CMD);
+		cmsg->complete = ssip_swbreak_complete;
+		dev_dbg(&cl->device, "Send SWBREAK\n");
+		hsi_async_write(cl, cmsg);
+	} else {
+		spin_unlock_bh(&ssi->lock);
+		ssip_xmit(cl);
+	}
+out:
+	ssip_free_data(msg);
+}
+
+static void ssip_port_event(struct hsi_client *cl, unsigned long event)
+{
+	switch (event) {
+	case HSI_EVENT_START_RX:
+		ssip_start_rx(cl);
+		break;
+	case HSI_EVENT_STOP_RX:
+		ssip_stop_rx(cl);
+		break;
+	default:
+		return;
+	}
+}
+
+static int ssip_pn_open(struct net_device *dev)
+{
+	struct hsi_client *cl = to_hsi_client(dev->dev.parent);
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	int err;
+
+	err = hsi_claim_port(cl, 1);
+	if (err < 0) {
+		dev_err(&cl->device, "SSI port already claimed\n");
+		return err;
+	}
+	err = hsi_register_port_event(cl, ssip_port_event);
+	if (err < 0) {
+		dev_err(&cl->device, "Register HSI port event failed (%d)\n",
+			err);
+		return err;
+	}
+	dev_dbg(&cl->device, "Configuring SSI port\n");
+	hsi_setup(cl);
+
+	if (!test_and_set_bit(SSIP_WAKETEST_FLAG, &ssi->flags))
+		ssi_waketest(cl, 1); /* FIXME: To be removed */
+
+	spin_lock_bh(&ssi->lock);
+	ssi->main_state = HANDSHAKE;
+	spin_unlock_bh(&ssi->lock);
+
+	ssip_send_bootinfo_req_cmd(cl);
+
+	return 0;
+}
+
+static int ssip_pn_stop(struct net_device *dev)
+{
+	struct hsi_client *cl = to_hsi_client(dev->dev.parent);
+
+	ssip_reset(cl);
+	hsi_unregister_port_event(cl);
+	hsi_release_port(cl);
+
+	return 0;
+}
+
+static void ssip_xmit_work(struct work_struct *work)
+{
+	struct ssi_protocol *ssi =
+				container_of(work, struct ssi_protocol, work);
+	struct hsi_client *cl = ssi->cl;
+
+	ssip_xmit(cl);
+}
+
+static int ssip_pn_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct hsi_client *cl = to_hsi_client(dev->dev.parent);
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *msg;
+
+	if ((skb->protocol != htons(ETH_P_PHONET)) ||
+					(skb->len < SSIP_MIN_PN_HDR))
+		goto drop;
+	/* Pad to 32-bits - FIXME: Revisit*/
+	if ((skb->len & 3) && skb_pad(skb, 4 - (skb->len & 3)))
+		goto inc_dropped;
+
+	/*
+	 * Modem sends Phonet messages over SSI with its own endianness.
+	 * Assume that modem has the same endianness as we do.
+	 */
+	if (skb_cow_head(skb, 0))
+		goto drop;
+
+	/* length field is exchanged in network byte order */
+	((u16 *)skb->data)[2] = htons(((u16 *)skb->data)[2]);
+
+	msg = ssip_alloc_data(ssi, skb, GFP_ATOMIC);
+	if (!msg) {
+		dev_dbg(&cl->device, "Dropping tx data: No memory\n");
+		goto drop;
+	}
+	msg->complete = ssip_tx_data_complete;
+
+	spin_lock_bh(&ssi->lock);
+	if (unlikely(ssi->main_state != ACTIVE)) {
+		spin_unlock_bh(&ssi->lock);
+		dev_dbg(&cl->device, "Dropping tx data: CMT is OFFLINE\n");
+		goto drop2;
+	}
+	list_add_tail(&msg->link, &ssi->txqueue);
+	ssi->txqueue_len++;
+	if (dev->tx_queue_len < ssi->txqueue_len) {
+		dev_info(&cl->device, "TX queue full %d\n", ssi->txqueue_len);
+		netif_stop_queue(dev);
+	}
+	if (ssi->send_state == SEND_IDLE) {
+		ssip_set_txstate(ssi, WAIT4READY);
+		spin_unlock_bh(&ssi->lock);
+		dev_dbg(&cl->device, "Start TX qlen %d\n", ssi->txqueue_len);
+		hsi_start_tx(cl);
+	} else if (ssi->send_state == SEND_READY) {
+		/* Needed for cmt-speech workaround */
+		dev_dbg(&cl->device, "Start TX on SEND READY qlen %d\n",
+							ssi->txqueue_len);
+		spin_unlock_bh(&ssi->lock);
+		schedule_work(&ssi->work);
+	} else {
+		spin_unlock_bh(&ssi->lock);
+	}
+	dev->stats.tx_packets++;
+	dev->stats.tx_bytes += skb->len;
+
+	return 0;
+drop2:
+	hsi_free_msg(msg);
+drop:
+	dev_kfree_skb(skb);
+inc_dropped:
+	dev->stats.tx_dropped++;
+
+	return 0;
+}
+
+/* CMT reset event handler */
+void ssip_reset_event(struct hsi_client *master)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(master);
+	dev_err(&ssi->cl->device, "CMT reset detected!\n");
+	ssip_error(ssi->cl);
+}
+EXPORT_SYMBOL_GPL(ssip_reset_event);
+
+static const struct net_device_ops ssip_pn_ops = {
+	.ndo_open	= ssip_pn_open,
+	.ndo_stop	= ssip_pn_stop,
+	.ndo_start_xmit	= ssip_pn_xmit,
+};
+
+static void ssip_pn_setup(struct net_device *dev)
+{
+	dev->features		= 0;
+	dev->netdev_ops		= &ssip_pn_ops;
+	dev->type		= ARPHRD_PHONET;
+	dev->flags		= IFF_POINTOPOINT | IFF_NOARP;
+	dev->mtu		= SSIP_DEFAULT_MTU;
+	dev->hard_header_len	= 1;
+	dev->dev_addr[0]	= PN_MEDIA_SOS;
+	dev->addr_len		= 1;
+	dev->tx_queue_len	= SSIP_TXQUEUE_LEN;
+
+	dev->needs_free_netdev	= true;
+	dev->header_ops		= &phonet_header_ops;
+}
+
+static int ssi_protocol_probe(struct device *dev)
+{
+	static const char ifname[] = "phonet%d";
+	struct hsi_client *cl = to_hsi_client(dev);
+	struct ssi_protocol *ssi;
+	int err;
+
+	ssi = kzalloc(sizeof(*ssi), GFP_KERNEL);
+	if (!ssi)
+		return -ENOMEM;
+
+	spin_lock_init(&ssi->lock);
+	timer_setup(&ssi->rx_wd, ssip_rx_wd, TIMER_DEFERRABLE);
+	timer_setup(&ssi->tx_wd, ssip_tx_wd, TIMER_DEFERRABLE);
+	timer_setup(&ssi->keep_alive, ssip_keep_alive, 0);
+	INIT_LIST_HEAD(&ssi->txqueue);
+	INIT_LIST_HEAD(&ssi->cmdqueue);
+	atomic_set(&ssi->tx_usecnt, 0);
+	hsi_client_set_drvdata(cl, ssi);
+	ssi->cl = cl;
+	INIT_WORK(&ssi->work, ssip_xmit_work);
+
+	ssi->channel_id_cmd = hsi_get_channel_id_by_name(cl, "mcsaab-control");
+	if (ssi->channel_id_cmd < 0) {
+		err = ssi->channel_id_cmd;
+		dev_err(dev, "Could not get cmd channel (%d)\n", err);
+		goto out;
+	}
+
+	ssi->channel_id_data = hsi_get_channel_id_by_name(cl, "mcsaab-data");
+	if (ssi->channel_id_data < 0) {
+		err = ssi->channel_id_data;
+		dev_err(dev, "Could not get data channel (%d)\n", err);
+		goto out;
+	}
+
+	err = ssip_alloc_cmds(ssi);
+	if (err < 0) {
+		dev_err(dev, "No memory for commands\n");
+		goto out;
+	}
+
+	ssi->netdev = alloc_netdev(0, ifname, NET_NAME_UNKNOWN, ssip_pn_setup);
+	if (!ssi->netdev) {
+		dev_err(dev, "No memory for netdev\n");
+		err = -ENOMEM;
+		goto out1;
+	}
+
+	/* MTU range: 6 - 65535 */
+	ssi->netdev->min_mtu = PHONET_MIN_MTU;
+	ssi->netdev->max_mtu = SSIP_MAX_MTU;
+
+	SET_NETDEV_DEV(ssi->netdev, dev);
+	netif_carrier_off(ssi->netdev);
+	err = register_netdev(ssi->netdev);
+	if (err < 0) {
+		dev_err(dev, "Register netdev failed (%d)\n", err);
+		goto out2;
+	}
+
+	list_add(&ssi->link, &ssip_list);
+
+	dev_dbg(dev, "channel configuration: cmd=%d, data=%d\n",
+		ssi->channel_id_cmd, ssi->channel_id_data);
+
+	return 0;
+out2:
+	free_netdev(ssi->netdev);
+out1:
+	ssip_free_cmds(ssi);
+out:
+	kfree(ssi);
+
+	return err;
+}
+
+static int ssi_protocol_remove(struct device *dev)
+{
+	struct hsi_client *cl = to_hsi_client(dev);
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+
+	list_del(&ssi->link);
+	unregister_netdev(ssi->netdev);
+	ssip_free_cmds(ssi);
+	hsi_client_set_drvdata(cl, NULL);
+	kfree(ssi);
+
+	return 0;
+}
+
+static struct hsi_client_driver ssip_driver = {
+	.driver = {
+		.name	= "ssi-protocol",
+		.owner	= THIS_MODULE,
+		.probe	= ssi_protocol_probe,
+		.remove	= ssi_protocol_remove,
+	},
+};
+
+static int __init ssip_init(void)
+{
+	pr_info("SSI protocol aka McSAAB added\n");
+
+	return hsi_register_client_driver(&ssip_driver);
+}
+module_init(ssip_init);
+
+static void __exit ssip_exit(void)
+{
+	hsi_unregister_client_driver(&ssip_driver);
+	pr_info("SSI protocol driver removed\n");
+}
+module_exit(ssip_exit);
+
+MODULE_ALIAS("hsi:ssi-protocol");
+MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
+MODULE_AUTHOR("Remi Denis-Courmont <remi.denis-courmont@nokia.com>");
+MODULE_DESCRIPTION("SSI protocol improved aka McSAAB");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hsi/controllers/Kconfig b/drivers/hsi/controllers/Kconfig
new file mode 100644
index 000000000..03ca5b558
--- /dev/null
+++ b/drivers/hsi/controllers/Kconfig
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# HSI controllers configuration
+#
+comment "HSI controllers"
+
+config OMAP_SSI
+	tristate "OMAP SSI hardware driver"
+	depends on HSI && OF && ARM && COMMON_CLK
+	depends on ARCH_OMAP3 || COMPILE_TEST
+	help
+	  SSI is a legacy version of HSI. It is usually used to connect
+	  an application engine with a cellular modem.
+	  If you say Y here, you will enable the OMAP SSI hardware driver.
+
+	  If unsure, say N.
diff --git a/drivers/hsi/controllers/Makefile b/drivers/hsi/controllers/Makefile
new file mode 100644
index 000000000..41aab9380
--- /dev/null
+++ b/drivers/hsi/controllers/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for HSI controllers drivers
+#
+
+omap_ssi-objs		+= omap_ssi_core.o omap_ssi_port.o
+obj-$(CONFIG_OMAP_SSI)	+= omap_ssi.o
diff --git a/drivers/hsi/controllers/omap_ssi.h b/drivers/hsi/controllers/omap_ssi.h
new file mode 100644
index 000000000..c72f74b5b
--- /dev/null
+++ b/drivers/hsi/controllers/omap_ssi.h
@@ -0,0 +1,164 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* OMAP SSI internal interface.
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ * Copyright (C) 2013 Sebastian Reichel
+ *
+ * Contact: Carlos Chinea <carlos.chinea@nokia.com>
+ */
+
+#ifndef __LINUX_HSI_OMAP_SSI_H__
+#define __LINUX_HSI_OMAP_SSI_H__
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/hsi/hsi.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+
+#define SSI_MAX_CHANNELS	8
+#define SSI_MAX_GDD_LCH		8
+#define SSI_BYTES_TO_FRAMES(x) ((((x) - 1) >> 2) + 1)
+
+#define SSI_WAKE_EN 0
+
+/**
+ * struct omap_ssm_ctx - OMAP synchronous serial module (TX/RX) context
+ * @mode: Bit transmission mode
+ * @channels: Number of channels
+ * @framesize: Frame size in bits
+ * @timeout: RX frame timeout
+ * @divisor: TX divider
+ * @arb_mode: Arbitration mode for TX frame (Round robin, priority)
+ */
+struct omap_ssm_ctx {
+	u32	mode;
+	u32	channels;
+	u32	frame_size;
+	union	{
+			u32	timeout; /* Rx Only */
+			struct	{
+					u32	arb_mode;
+					u32	divisor;
+			}; /* Tx only */
+	};
+};
+
+/**
+ * struct omap_ssi_port - OMAP SSI port data
+ * @dev: device associated to the port (HSI port)
+ * @pdev: platform device associated to the port
+ * @sst_dma: SSI transmitter physical base address
+ * @ssr_dma: SSI receiver physical base address
+ * @sst_base: SSI transmitter base address
+ * @ssr_base: SSI receiver base address
+ * @wk_lock: spin lock to serialize access to the wake lines
+ * @lock: Spin lock to serialize access to the SSI port
+ * @channels: Current number of channels configured (1,2,4 or 8)
+ * @txqueue: TX message queues
+ * @rxqueue: RX message queues
+ * @brkqueue: Queue of incoming HWBREAK requests (FRAME mode)
+ * @errqueue: Queue for failed messages
+ * @errqueue_work: Delayed Work for failed messages
+ * @irq: IRQ number
+ * @wake_irq: IRQ number for incoming wake line (-1 if none)
+ * @wake_gpio: GPIO number for incoming wake line (-1 if none)
+ * @flags: flags to keep track of states
+ * @wk_refcount: Reference count for output wake line
+ * @work: worker for starting TX
+ * @sys_mpu_enable: Context for the interrupt enable register for irq 0
+ * @sst: Context for the synchronous serial transmitter
+ * @ssr: Context for the synchronous serial receiver
+ */
+struct omap_ssi_port {
+	struct device		*dev;
+	struct device           *pdev;
+	dma_addr_t		sst_dma;
+	dma_addr_t		ssr_dma;
+	void __iomem		*sst_base;
+	void __iomem		*ssr_base;
+	spinlock_t		wk_lock;
+	spinlock_t		lock;
+	unsigned int		channels;
+	struct list_head	txqueue[SSI_MAX_CHANNELS];
+	struct list_head	rxqueue[SSI_MAX_CHANNELS];
+	struct list_head	brkqueue;
+	struct list_head	errqueue;
+	struct delayed_work	errqueue_work;
+	unsigned int		irq;
+	int			wake_irq;
+	struct gpio_desc	*wake_gpio;
+	bool			wktest:1; /* FIXME: HACK to be removed */
+	unsigned long		flags;
+	unsigned int		wk_refcount;
+	struct work_struct	work;
+	/* OMAP SSI port context */
+	u32			sys_mpu_enable; /* We use only one irq */
+	struct omap_ssm_ctx	sst;
+	struct omap_ssm_ctx	ssr;
+	u32			loss_count;
+	u32			port_id;
+#ifdef CONFIG_DEBUG_FS
+	struct dentry *dir;
+#endif
+};
+
+/**
+ * struct gdd_trn - GDD transaction data
+ * @msg: Pointer to the HSI message being served
+ * @sg: Pointer to the current sg entry being served
+ */
+struct gdd_trn {
+	struct hsi_msg		*msg;
+	struct scatterlist	*sg;
+};
+
+/**
+ * struct omap_ssi_controller - OMAP SSI controller data
+ * @dev: device associated to the controller (HSI controller)
+ * @sys: SSI I/O base address
+ * @gdd: GDD I/O base address
+ * @fck: SSI functional clock
+ * @gdd_irq: IRQ line for GDD
+ * @gdd_tasklet: bottom half for DMA transfers
+ * @gdd_trn: Array of GDD transaction data for ongoing GDD transfers
+ * @lock: lock to serialize access to GDD
+ * @fck_nb: DVFS notfifier block
+ * @fck_rate: clock rate
+ * @loss_count: To follow if we need to restore context or not
+ * @max_speed: Maximum TX speed (Kb/s) set by the clients.
+ * @gdd_gcr: SSI GDD saved context
+ * @get_loss: Pointer to omap_pm_get_dev_context_loss_count, if any
+ * @port: Array of pointers of the ports of the controller
+ * @dir: Debugfs SSI root directory
+ */
+struct omap_ssi_controller {
+	struct device		*dev;
+	void __iomem		*sys;
+	void __iomem		*gdd;
+	struct clk		*fck;
+	unsigned int		gdd_irq;
+	struct tasklet_struct	gdd_tasklet;
+	struct gdd_trn		gdd_trn[SSI_MAX_GDD_LCH];
+	spinlock_t		lock;
+	struct notifier_block	fck_nb;
+	unsigned long		fck_rate;
+	u32			loss_count;
+	u32			max_speed;
+	/* OMAP SSI Controller context */
+	u32			gdd_gcr;
+	int			(*get_loss)(struct device *dev);
+	struct omap_ssi_port	**port;
+#ifdef CONFIG_DEBUG_FS
+	struct dentry *dir;
+#endif
+};
+
+void omap_ssi_port_update_fclk(struct hsi_controller *ssi,
+			       struct omap_ssi_port *omap_port);
+
+extern struct platform_driver ssi_port_pdriver;
+
+#endif /* __LINUX_HSI_OMAP_SSI_H__ */
diff --git a/drivers/hsi/controllers/omap_ssi_core.c b/drivers/hsi/controllers/omap_ssi_core.c
new file mode 100644
index 000000000..26f2c3c01
--- /dev/null
+++ b/drivers/hsi/controllers/omap_ssi_core.c
@@ -0,0 +1,654 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* OMAP SSI driver.
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ * Copyright (C) 2014 Sebastian Reichel <sre@kernel.org>
+ *
+ * Contact: Carlos Chinea <carlos.chinea@nokia.com>
+ */
+
+#include <linux/compiler.h>
+#include <linux/err.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/delay.h>
+#include <linux/seq_file.h>
+#include <linux/scatterlist.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/debugfs.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/pm_runtime.h>
+#include <linux/of_platform.h>
+#include <linux/hsi/hsi.h>
+#include <linux/idr.h>
+
+#include "omap_ssi_regs.h"
+#include "omap_ssi.h"
+
+/* For automatically allocated device IDs */
+static DEFINE_IDA(platform_omap_ssi_ida);
+
+#ifdef CONFIG_DEBUG_FS
+static int ssi_regs_show(struct seq_file *m, void *p __maybe_unused)
+{
+	struct hsi_controller *ssi = m->private;
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	void __iomem *sys = omap_ssi->sys;
+
+	pm_runtime_get_sync(ssi->device.parent);
+	seq_printf(m, "REVISION\t: 0x%08x\n",  readl(sys + SSI_REVISION_REG));
+	seq_printf(m, "SYSCONFIG\t: 0x%08x\n", readl(sys + SSI_SYSCONFIG_REG));
+	seq_printf(m, "SYSSTATUS\t: 0x%08x\n", readl(sys + SSI_SYSSTATUS_REG));
+	pm_runtime_put(ssi->device.parent);
+
+	return 0;
+}
+
+static int ssi_gdd_regs_show(struct seq_file *m, void *p __maybe_unused)
+{
+	struct hsi_controller *ssi = m->private;
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	void __iomem *gdd = omap_ssi->gdd;
+	void __iomem *sys = omap_ssi->sys;
+	int lch;
+
+	pm_runtime_get_sync(ssi->device.parent);
+
+	seq_printf(m, "GDD_MPU_STATUS\t: 0x%08x\n",
+		readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG));
+	seq_printf(m, "GDD_MPU_ENABLE\t: 0x%08x\n\n",
+		readl(sys + SSI_GDD_MPU_IRQ_ENABLE_REG));
+	seq_printf(m, "HW_ID\t\t: 0x%08x\n",
+				readl(gdd + SSI_GDD_HW_ID_REG));
+	seq_printf(m, "PPORT_ID\t: 0x%08x\n",
+				readl(gdd + SSI_GDD_PPORT_ID_REG));
+	seq_printf(m, "MPORT_ID\t: 0x%08x\n",
+				readl(gdd + SSI_GDD_MPORT_ID_REG));
+	seq_printf(m, "TEST\t\t: 0x%08x\n",
+				readl(gdd + SSI_GDD_TEST_REG));
+	seq_printf(m, "GCR\t\t: 0x%08x\n",
+				readl(gdd + SSI_GDD_GCR_REG));
+
+	for (lch = 0; lch < SSI_MAX_GDD_LCH; lch++) {
+		seq_printf(m, "\nGDD LCH %d\n=========\n", lch);
+		seq_printf(m, "CSDP\t\t: 0x%04x\n",
+				readw(gdd + SSI_GDD_CSDP_REG(lch)));
+		seq_printf(m, "CCR\t\t: 0x%04x\n",
+				readw(gdd + SSI_GDD_CCR_REG(lch)));
+		seq_printf(m, "CICR\t\t: 0x%04x\n",
+				readw(gdd + SSI_GDD_CICR_REG(lch)));
+		seq_printf(m, "CSR\t\t: 0x%04x\n",
+				readw(gdd + SSI_GDD_CSR_REG(lch)));
+		seq_printf(m, "CSSA\t\t: 0x%08x\n",
+				readl(gdd + SSI_GDD_CSSA_REG(lch)));
+		seq_printf(m, "CDSA\t\t: 0x%08x\n",
+				readl(gdd + SSI_GDD_CDSA_REG(lch)));
+		seq_printf(m, "CEN\t\t: 0x%04x\n",
+				readw(gdd + SSI_GDD_CEN_REG(lch)));
+		seq_printf(m, "CSAC\t\t: 0x%04x\n",
+				readw(gdd + SSI_GDD_CSAC_REG(lch)));
+		seq_printf(m, "CDAC\t\t: 0x%04x\n",
+				readw(gdd + SSI_GDD_CDAC_REG(lch)));
+		seq_printf(m, "CLNK_CTRL\t: 0x%04x\n",
+				readw(gdd + SSI_GDD_CLNK_CTRL_REG(lch)));
+	}
+
+	pm_runtime_put(ssi->device.parent);
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(ssi_regs);
+DEFINE_SHOW_ATTRIBUTE(ssi_gdd_regs);
+
+static int ssi_debug_add_ctrl(struct hsi_controller *ssi)
+{
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	struct dentry *dir;
+
+	/* SSI controller */
+	omap_ssi->dir = debugfs_create_dir(dev_name(&ssi->device), NULL);
+	if (!omap_ssi->dir)
+		return -ENOMEM;
+
+	debugfs_create_file("regs", S_IRUGO, omap_ssi->dir, ssi,
+								&ssi_regs_fops);
+	/* SSI GDD (DMA) */
+	dir = debugfs_create_dir("gdd", omap_ssi->dir);
+	if (!dir)
+		goto rback;
+	debugfs_create_file("regs", S_IRUGO, dir, ssi, &ssi_gdd_regs_fops);
+
+	return 0;
+rback:
+	debugfs_remove_recursive(omap_ssi->dir);
+
+	return -ENOMEM;
+}
+
+static void ssi_debug_remove_ctrl(struct hsi_controller *ssi)
+{
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+
+	debugfs_remove_recursive(omap_ssi->dir);
+}
+#endif /* CONFIG_DEBUG_FS */
+
+/*
+ * FIXME: Horrible HACK needed until we remove the useless wakeline test
+ * in the CMT. To be removed !!!!
+ */
+void ssi_waketest(struct hsi_client *cl, unsigned int enable)
+{
+	struct hsi_port *port = hsi_get_port(cl);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+
+	omap_port->wktest = !!enable;
+	if (omap_port->wktest) {
+		pm_runtime_get_sync(ssi->device.parent);
+		writel_relaxed(SSI_WAKE(0),
+				omap_ssi->sys + SSI_SET_WAKE_REG(port->num));
+	} else {
+		writel_relaxed(SSI_WAKE(0),
+				omap_ssi->sys +	SSI_CLEAR_WAKE_REG(port->num));
+		pm_runtime_put(ssi->device.parent);
+	}
+}
+EXPORT_SYMBOL_GPL(ssi_waketest);
+
+static void ssi_gdd_complete(struct hsi_controller *ssi, unsigned int lch)
+{
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	struct hsi_msg *msg = omap_ssi->gdd_trn[lch].msg;
+	struct hsi_port *port = to_hsi_port(msg->cl->device.parent);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	unsigned int dir;
+	u32 csr;
+	u32 val;
+
+	spin_lock(&omap_ssi->lock);
+
+	val = readl(omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
+	val &= ~SSI_GDD_LCH(lch);
+	writel_relaxed(val, omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
+
+	if (msg->ttype == HSI_MSG_READ) {
+		dir = DMA_FROM_DEVICE;
+		val = SSI_DATAAVAILABLE(msg->channel);
+		pm_runtime_put(omap_port->pdev);
+	} else {
+		dir = DMA_TO_DEVICE;
+		val = SSI_DATAACCEPT(msg->channel);
+		/* Keep clocks reference for write pio event */
+	}
+	dma_unmap_sg(&ssi->device, msg->sgt.sgl, msg->sgt.nents, dir);
+	csr = readw(omap_ssi->gdd + SSI_GDD_CSR_REG(lch));
+	omap_ssi->gdd_trn[lch].msg = NULL; /* release GDD lch */
+	dev_dbg(&port->device, "DMA completed ch %d ttype %d\n",
+				msg->channel, msg->ttype);
+	spin_unlock(&omap_ssi->lock);
+	if (csr & SSI_CSR_TOUR) { /* Timeout error */
+		msg->status = HSI_STATUS_ERROR;
+		msg->actual_len = 0;
+		spin_lock(&omap_port->lock);
+		list_del(&msg->link); /* Dequeue msg */
+		spin_unlock(&omap_port->lock);
+
+		list_add_tail(&msg->link, &omap_port->errqueue);
+		schedule_delayed_work(&omap_port->errqueue_work, 0);
+		return;
+	}
+	spin_lock(&omap_port->lock);
+	val |= readl(omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+	writel_relaxed(val, omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+	spin_unlock(&omap_port->lock);
+
+	msg->status = HSI_STATUS_COMPLETED;
+	msg->actual_len = sg_dma_len(msg->sgt.sgl);
+}
+
+static void ssi_gdd_tasklet(unsigned long dev)
+{
+	struct hsi_controller *ssi = (struct hsi_controller *)dev;
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	void __iomem *sys = omap_ssi->sys;
+	unsigned int lch;
+	u32 status_reg;
+
+	pm_runtime_get(ssi->device.parent);
+
+	if (!pm_runtime_active(ssi->device.parent)) {
+		dev_warn(ssi->device.parent, "ssi_gdd_tasklet called without runtime PM!\n");
+		pm_runtime_put(ssi->device.parent);
+		return;
+	}
+
+	status_reg = readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG);
+	for (lch = 0; lch < SSI_MAX_GDD_LCH; lch++) {
+		if (status_reg & SSI_GDD_LCH(lch))
+			ssi_gdd_complete(ssi, lch);
+	}
+	writel_relaxed(status_reg, sys + SSI_GDD_MPU_IRQ_STATUS_REG);
+	status_reg = readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG);
+
+	pm_runtime_put(ssi->device.parent);
+
+	if (status_reg)
+		tasklet_hi_schedule(&omap_ssi->gdd_tasklet);
+	else
+		enable_irq(omap_ssi->gdd_irq);
+
+}
+
+static irqreturn_t ssi_gdd_isr(int irq, void *ssi)
+{
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+
+	tasklet_hi_schedule(&omap_ssi->gdd_tasklet);
+	disable_irq_nosync(irq);
+
+	return IRQ_HANDLED;
+}
+
+static unsigned long ssi_get_clk_rate(struct hsi_controller *ssi)
+{
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	unsigned long rate = clk_get_rate(omap_ssi->fck);
+	return rate;
+}
+
+static int ssi_clk_event(struct notifier_block *nb, unsigned long event,
+								void *data)
+{
+	struct omap_ssi_controller *omap_ssi = container_of(nb,
+					struct omap_ssi_controller, fck_nb);
+	struct hsi_controller *ssi = to_hsi_controller(omap_ssi->dev);
+	struct clk_notifier_data *clk_data = data;
+	struct omap_ssi_port *omap_port;
+	int i;
+
+	switch (event) {
+	case PRE_RATE_CHANGE:
+		dev_dbg(&ssi->device, "pre rate change\n");
+
+		for (i = 0; i < ssi->num_ports; i++) {
+			omap_port = omap_ssi->port[i];
+
+			if (!omap_port)
+				continue;
+
+			/* Workaround for SWBREAK + CAwake down race in CMT */
+			disable_irq(omap_port->wake_irq);
+
+			/* stop all ssi communication */
+			pinctrl_pm_select_idle_state(omap_port->pdev);
+			udelay(1); /* wait for racing frames */
+		}
+
+		break;
+	case ABORT_RATE_CHANGE:
+		dev_dbg(&ssi->device, "abort rate change\n");
+		fallthrough;
+	case POST_RATE_CHANGE:
+		dev_dbg(&ssi->device, "post rate change (%lu -> %lu)\n",
+			clk_data->old_rate, clk_data->new_rate);
+		omap_ssi->fck_rate = DIV_ROUND_CLOSEST(clk_data->new_rate, 1000); /* kHz */
+
+		for (i = 0; i < ssi->num_ports; i++) {
+			omap_port = omap_ssi->port[i];
+
+			if (!omap_port)
+				continue;
+
+			omap_ssi_port_update_fclk(ssi, omap_port);
+
+			/* resume ssi communication */
+			pinctrl_pm_select_default_state(omap_port->pdev);
+			enable_irq(omap_port->wake_irq);
+		}
+
+		break;
+	default:
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int ssi_get_iomem(struct platform_device *pd,
+		const char *name, void __iomem **pbase, dma_addr_t *phy)
+{
+	struct resource *mem;
+	void __iomem *base;
+	struct hsi_controller *ssi = platform_get_drvdata(pd);
+
+	mem = platform_get_resource_byname(pd, IORESOURCE_MEM, name);
+	base = devm_ioremap_resource(&ssi->device, mem);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	*pbase = base;
+
+	if (phy)
+		*phy = mem->start;
+
+	return 0;
+}
+
+static int ssi_add_controller(struct hsi_controller *ssi,
+						struct platform_device *pd)
+{
+	struct omap_ssi_controller *omap_ssi;
+	int err;
+
+	omap_ssi = devm_kzalloc(&ssi->device, sizeof(*omap_ssi), GFP_KERNEL);
+	if (!omap_ssi)
+		return -ENOMEM;
+
+	err = ida_simple_get(&platform_omap_ssi_ida, 0, 0, GFP_KERNEL);
+	if (err < 0)
+		return err;
+	ssi->id = err;
+
+	ssi->owner = THIS_MODULE;
+	ssi->device.parent = &pd->dev;
+	dev_set_name(&ssi->device, "ssi%d", ssi->id);
+	hsi_controller_set_drvdata(ssi, omap_ssi);
+	omap_ssi->dev = &ssi->device;
+	err = ssi_get_iomem(pd, "sys", &omap_ssi->sys, NULL);
+	if (err < 0)
+		goto out_err;
+	err = ssi_get_iomem(pd, "gdd", &omap_ssi->gdd, NULL);
+	if (err < 0)
+		goto out_err;
+	err = platform_get_irq_byname(pd, "gdd_mpu");
+	if (err < 0)
+		goto out_err;
+	omap_ssi->gdd_irq = err;
+	tasklet_init(&omap_ssi->gdd_tasklet, ssi_gdd_tasklet,
+							(unsigned long)ssi);
+	err = devm_request_irq(&ssi->device, omap_ssi->gdd_irq, ssi_gdd_isr,
+						0, "gdd_mpu", ssi);
+	if (err < 0) {
+		dev_err(&ssi->device, "Request GDD IRQ %d failed (%d)",
+							omap_ssi->gdd_irq, err);
+		goto out_err;
+	}
+
+	omap_ssi->port = devm_kcalloc(&ssi->device, ssi->num_ports,
+				      sizeof(*omap_ssi->port), GFP_KERNEL);
+	if (!omap_ssi->port) {
+		err = -ENOMEM;
+		goto out_err;
+	}
+
+	omap_ssi->fck = devm_clk_get(&ssi->device, "ssi_ssr_fck");
+	if (IS_ERR(omap_ssi->fck)) {
+		dev_err(&pd->dev, "Could not acquire clock \"ssi_ssr_fck\": %li\n",
+			PTR_ERR(omap_ssi->fck));
+		err = -ENODEV;
+		goto out_err;
+	}
+
+	omap_ssi->fck_nb.notifier_call = ssi_clk_event;
+	omap_ssi->fck_nb.priority = INT_MAX;
+	clk_notifier_register(omap_ssi->fck, &omap_ssi->fck_nb);
+
+	/* TODO: find register, which can be used to detect context loss */
+	omap_ssi->get_loss = NULL;
+
+	omap_ssi->max_speed = UINT_MAX;
+	spin_lock_init(&omap_ssi->lock);
+	err = hsi_register_controller(ssi);
+
+	if (err < 0)
+		goto out_err;
+
+	return 0;
+
+out_err:
+	ida_simple_remove(&platform_omap_ssi_ida, ssi->id);
+	return err;
+}
+
+static int ssi_hw_init(struct hsi_controller *ssi)
+{
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	int err;
+
+	err = pm_runtime_resume_and_get(ssi->device.parent);
+	if (err < 0) {
+		dev_err(&ssi->device, "runtime PM failed %d\n", err);
+		return err;
+	}
+	/* Resetting GDD */
+	writel_relaxed(SSI_SWRESET, omap_ssi->gdd + SSI_GDD_GRST_REG);
+	/* Get FCK rate in kHz */
+	omap_ssi->fck_rate = DIV_ROUND_CLOSEST(ssi_get_clk_rate(ssi), 1000);
+	dev_dbg(&ssi->device, "SSI fck rate %lu kHz\n", omap_ssi->fck_rate);
+
+	writel_relaxed(SSI_CLK_AUTOGATING_ON, omap_ssi->sys + SSI_GDD_GCR_REG);
+	omap_ssi->gdd_gcr = SSI_CLK_AUTOGATING_ON;
+	pm_runtime_put_sync(ssi->device.parent);
+
+	return 0;
+}
+
+static void ssi_remove_controller(struct hsi_controller *ssi)
+{
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	int id = ssi->id;
+	tasklet_kill(&omap_ssi->gdd_tasklet);
+	hsi_unregister_controller(ssi);
+	clk_notifier_unregister(omap_ssi->fck, &omap_ssi->fck_nb);
+	ida_simple_remove(&platform_omap_ssi_ida, id);
+}
+
+static inline int ssi_of_get_available_ports_count(const struct device_node *np)
+{
+	struct device_node *child;
+	int num = 0;
+
+	for_each_available_child_of_node(np, child)
+		if (of_device_is_compatible(child, "ti,omap3-ssi-port"))
+			num++;
+
+	return num;
+}
+
+static int ssi_remove_ports(struct device *dev, void *c)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+
+	if (!dev->of_node)
+		return 0;
+
+	of_node_clear_flag(dev->of_node, OF_POPULATED);
+	of_device_unregister(pdev);
+
+	return 0;
+}
+
+static int ssi_probe(struct platform_device *pd)
+{
+	struct platform_device *childpdev;
+	struct device_node *np = pd->dev.of_node;
+	struct device_node *child;
+	struct hsi_controller *ssi;
+	int err;
+	int num_ports;
+
+	if (!np) {
+		dev_err(&pd->dev, "missing device tree data\n");
+		return -EINVAL;
+	}
+
+	num_ports = ssi_of_get_available_ports_count(np);
+
+	ssi = hsi_alloc_controller(num_ports, GFP_KERNEL);
+	if (!ssi) {
+		dev_err(&pd->dev, "No memory for controller\n");
+		return -ENOMEM;
+	}
+
+	platform_set_drvdata(pd, ssi);
+
+	err = ssi_add_controller(ssi, pd);
+	if (err < 0) {
+		hsi_put_controller(ssi);
+		goto out1;
+	}
+
+	pm_runtime_enable(&pd->dev);
+
+	err = ssi_hw_init(ssi);
+	if (err < 0)
+		goto out2;
+#ifdef CONFIG_DEBUG_FS
+	err = ssi_debug_add_ctrl(ssi);
+	if (err < 0)
+		goto out2;
+#endif
+
+	for_each_available_child_of_node(np, child) {
+		if (!of_device_is_compatible(child, "ti,omap3-ssi-port"))
+			continue;
+
+		childpdev = of_platform_device_create(child, NULL, &pd->dev);
+		if (!childpdev) {
+			err = -ENODEV;
+			dev_err(&pd->dev, "failed to create ssi controller port\n");
+			of_node_put(child);
+			goto out3;
+		}
+	}
+
+	dev_info(&pd->dev, "ssi controller %d initialized (%d ports)!\n",
+		ssi->id, num_ports);
+	return err;
+out3:
+	device_for_each_child(&pd->dev, NULL, ssi_remove_ports);
+out2:
+	ssi_remove_controller(ssi);
+	pm_runtime_disable(&pd->dev);
+out1:
+	platform_set_drvdata(pd, NULL);
+
+	return err;
+}
+
+static int ssi_remove(struct platform_device *pd)
+{
+	struct hsi_controller *ssi = platform_get_drvdata(pd);
+
+	/* cleanup of of_platform_populate() call */
+	device_for_each_child(&pd->dev, NULL, ssi_remove_ports);
+
+#ifdef CONFIG_DEBUG_FS
+	ssi_debug_remove_ctrl(ssi);
+#endif
+	ssi_remove_controller(ssi);
+	platform_set_drvdata(pd, NULL);
+
+	pm_runtime_disable(&pd->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int omap_ssi_runtime_suspend(struct device *dev)
+{
+	struct hsi_controller *ssi = dev_get_drvdata(dev);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+
+	dev_dbg(dev, "runtime suspend!\n");
+
+	if (omap_ssi->get_loss)
+		omap_ssi->loss_count =
+				omap_ssi->get_loss(ssi->device.parent);
+
+	return 0;
+}
+
+static int omap_ssi_runtime_resume(struct device *dev)
+{
+	struct hsi_controller *ssi = dev_get_drvdata(dev);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+
+	dev_dbg(dev, "runtime resume!\n");
+
+	if ((omap_ssi->get_loss) && (omap_ssi->loss_count ==
+				omap_ssi->get_loss(ssi->device.parent)))
+		return 0;
+
+	writel_relaxed(omap_ssi->gdd_gcr, omap_ssi->gdd + SSI_GDD_GCR_REG);
+
+	return 0;
+}
+
+static const struct dev_pm_ops omap_ssi_pm_ops = {
+	SET_RUNTIME_PM_OPS(omap_ssi_runtime_suspend, omap_ssi_runtime_resume,
+		NULL)
+};
+
+#define DEV_PM_OPS     (&omap_ssi_pm_ops)
+#else
+#define DEV_PM_OPS     NULL
+#endif
+
+#ifdef CONFIG_OF
+static const struct of_device_id omap_ssi_of_match[] = {
+	{ .compatible = "ti,omap3-ssi", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, omap_ssi_of_match);
+#else
+#define omap_ssi_of_match NULL
+#endif
+
+static struct platform_driver ssi_pdriver = {
+	.probe = ssi_probe,
+	.remove	= ssi_remove,
+	.driver	= {
+		.name	= "omap_ssi",
+		.pm     = DEV_PM_OPS,
+		.of_match_table = omap_ssi_of_match,
+	},
+};
+
+static int __init ssi_init(void) {
+	int ret;
+
+	ret = platform_driver_register(&ssi_pdriver);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&ssi_port_pdriver);
+	if (ret) {
+		platform_driver_unregister(&ssi_pdriver);
+		return ret;
+	}
+
+	return 0;
+}
+module_init(ssi_init);
+
+static void __exit ssi_exit(void) {
+	platform_driver_unregister(&ssi_port_pdriver);
+	platform_driver_unregister(&ssi_pdriver);
+}
+module_exit(ssi_exit);
+
+MODULE_ALIAS("platform:omap_ssi");
+MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
+MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
+MODULE_DESCRIPTION("Synchronous Serial Interface Driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/hsi/controllers/omap_ssi_port.c b/drivers/hsi/controllers/omap_ssi_port.c
new file mode 100644
index 000000000..b9495b720
--- /dev/null
+++ b/drivers/hsi/controllers/omap_ssi_port.c
@@ -0,0 +1,1406 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* OMAP SSI port driver.
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ * Copyright (C) 2014 Sebastian Reichel <sre@kernel.org>
+ *
+ * Contact: Carlos Chinea <carlos.chinea@nokia.com>
+ */
+
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/pm_runtime.h>
+#include <linux/delay.h>
+
+#include <linux/gpio/consumer.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/debugfs.h>
+
+#include "omap_ssi_regs.h"
+#include "omap_ssi.h"
+
+static inline int hsi_dummy_msg(struct hsi_msg *msg __maybe_unused)
+{
+	return 0;
+}
+
+static inline int hsi_dummy_cl(struct hsi_client *cl __maybe_unused)
+{
+	return 0;
+}
+
+static inline unsigned int ssi_wakein(struct hsi_port *port)
+{
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	return gpiod_get_value(omap_port->wake_gpio);
+}
+
+#ifdef CONFIG_DEBUG_FS
+static void ssi_debug_remove_port(struct hsi_port *port)
+{
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+
+	debugfs_remove_recursive(omap_port->dir);
+}
+
+static int ssi_port_regs_show(struct seq_file *m, void *p __maybe_unused)
+{
+	struct hsi_port *port = m->private;
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	void __iomem	*base = omap_ssi->sys;
+	unsigned int ch;
+
+	pm_runtime_get_sync(omap_port->pdev);
+	if (omap_port->wake_irq > 0)
+		seq_printf(m, "CAWAKE\t\t: %d\n", ssi_wakein(port));
+	seq_printf(m, "WAKE\t\t: 0x%08x\n",
+				readl(base + SSI_WAKE_REG(port->num)));
+	seq_printf(m, "MPU_ENABLE_IRQ%d\t: 0x%08x\n", 0,
+			readl(base + SSI_MPU_ENABLE_REG(port->num, 0)));
+	seq_printf(m, "MPU_STATUS_IRQ%d\t: 0x%08x\n", 0,
+			readl(base + SSI_MPU_STATUS_REG(port->num, 0)));
+	/* SST */
+	base = omap_port->sst_base;
+	seq_puts(m, "\nSST\n===\n");
+	seq_printf(m, "ID SST\t\t: 0x%08x\n",
+				readl(base + SSI_SST_ID_REG));
+	seq_printf(m, "MODE\t\t: 0x%08x\n",
+				readl(base + SSI_SST_MODE_REG));
+	seq_printf(m, "FRAMESIZE\t: 0x%08x\n",
+				readl(base + SSI_SST_FRAMESIZE_REG));
+	seq_printf(m, "DIVISOR\t\t: 0x%08x\n",
+				readl(base + SSI_SST_DIVISOR_REG));
+	seq_printf(m, "CHANNELS\t: 0x%08x\n",
+				readl(base + SSI_SST_CHANNELS_REG));
+	seq_printf(m, "ARBMODE\t\t: 0x%08x\n",
+				readl(base + SSI_SST_ARBMODE_REG));
+	seq_printf(m, "TXSTATE\t\t: 0x%08x\n",
+				readl(base + SSI_SST_TXSTATE_REG));
+	seq_printf(m, "BUFSTATE\t: 0x%08x\n",
+				readl(base + SSI_SST_BUFSTATE_REG));
+	seq_printf(m, "BREAK\t\t: 0x%08x\n",
+				readl(base + SSI_SST_BREAK_REG));
+	for (ch = 0; ch < omap_port->channels; ch++) {
+		seq_printf(m, "BUFFER_CH%d\t: 0x%08x\n", ch,
+				readl(base + SSI_SST_BUFFER_CH_REG(ch)));
+	}
+	/* SSR */
+	base = omap_port->ssr_base;
+	seq_puts(m, "\nSSR\n===\n");
+	seq_printf(m, "ID SSR\t\t: 0x%08x\n",
+				readl(base + SSI_SSR_ID_REG));
+	seq_printf(m, "MODE\t\t: 0x%08x\n",
+				readl(base + SSI_SSR_MODE_REG));
+	seq_printf(m, "FRAMESIZE\t: 0x%08x\n",
+				readl(base + SSI_SSR_FRAMESIZE_REG));
+	seq_printf(m, "CHANNELS\t: 0x%08x\n",
+				readl(base + SSI_SSR_CHANNELS_REG));
+	seq_printf(m, "TIMEOUT\t\t: 0x%08x\n",
+				readl(base + SSI_SSR_TIMEOUT_REG));
+	seq_printf(m, "RXSTATE\t\t: 0x%08x\n",
+				readl(base + SSI_SSR_RXSTATE_REG));
+	seq_printf(m, "BUFSTATE\t: 0x%08x\n",
+				readl(base + SSI_SSR_BUFSTATE_REG));
+	seq_printf(m, "BREAK\t\t: 0x%08x\n",
+				readl(base + SSI_SSR_BREAK_REG));
+	seq_printf(m, "ERROR\t\t: 0x%08x\n",
+				readl(base + SSI_SSR_ERROR_REG));
+	seq_printf(m, "ERRORACK\t: 0x%08x\n",
+				readl(base + SSI_SSR_ERRORACK_REG));
+	for (ch = 0; ch < omap_port->channels; ch++) {
+		seq_printf(m, "BUFFER_CH%d\t: 0x%08x\n", ch,
+				readl(base + SSI_SSR_BUFFER_CH_REG(ch)));
+	}
+	pm_runtime_put_autosuspend(omap_port->pdev);
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(ssi_port_regs);
+
+static int ssi_div_get(void *data, u64 *val)
+{
+	struct hsi_port *port = data;
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+
+	pm_runtime_get_sync(omap_port->pdev);
+	*val = readl(omap_port->sst_base + SSI_SST_DIVISOR_REG);
+	pm_runtime_put_autosuspend(omap_port->pdev);
+
+	return 0;
+}
+
+static int ssi_div_set(void *data, u64 val)
+{
+	struct hsi_port *port = data;
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+
+	if (val > 127)
+		return -EINVAL;
+
+	pm_runtime_get_sync(omap_port->pdev);
+	writel(val, omap_port->sst_base + SSI_SST_DIVISOR_REG);
+	omap_port->sst.divisor = val;
+	pm_runtime_put_autosuspend(omap_port->pdev);
+
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(ssi_sst_div_fops, ssi_div_get, ssi_div_set, "%llu\n");
+
+static int ssi_debug_add_port(struct omap_ssi_port *omap_port,
+				     struct dentry *dir)
+{
+	struct hsi_port *port = to_hsi_port(omap_port->dev);
+
+	dir = debugfs_create_dir(dev_name(omap_port->dev), dir);
+	if (!dir)
+		return -ENOMEM;
+	omap_port->dir = dir;
+	debugfs_create_file("regs", S_IRUGO, dir, port, &ssi_port_regs_fops);
+	dir = debugfs_create_dir("sst", dir);
+	if (!dir)
+		return -ENOMEM;
+	debugfs_create_file_unsafe("divisor", 0644, dir, port,
+				   &ssi_sst_div_fops);
+
+	return 0;
+}
+#endif
+
+static void ssi_process_errqueue(struct work_struct *work)
+{
+	struct omap_ssi_port *omap_port;
+	struct list_head *head, *tmp;
+	struct hsi_msg *msg;
+
+	omap_port = container_of(work, struct omap_ssi_port, errqueue_work.work);
+
+	list_for_each_safe(head, tmp, &omap_port->errqueue) {
+		msg = list_entry(head, struct hsi_msg, link);
+		msg->complete(msg);
+		list_del(head);
+	}
+}
+
+static int ssi_claim_lch(struct hsi_msg *msg)
+{
+
+	struct hsi_port *port = hsi_get_port(msg->cl);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	int lch;
+
+	for (lch = 0; lch < SSI_MAX_GDD_LCH; lch++)
+		if (!omap_ssi->gdd_trn[lch].msg) {
+			omap_ssi->gdd_trn[lch].msg = msg;
+			omap_ssi->gdd_trn[lch].sg = msg->sgt.sgl;
+			return lch;
+		}
+
+	return -EBUSY;
+}
+
+static int ssi_start_dma(struct hsi_msg *msg, int lch)
+{
+	struct hsi_port *port = hsi_get_port(msg->cl);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	void __iomem *gdd = omap_ssi->gdd;
+	int err;
+	u16 csdp;
+	u16 ccr;
+	u32 s_addr;
+	u32 d_addr;
+	u32 tmp;
+
+	/* Hold clocks during the transfer */
+	pm_runtime_get(omap_port->pdev);
+
+	if (!pm_runtime_active(omap_port->pdev)) {
+		dev_warn(&port->device, "ssi_start_dma called without runtime PM!\n");
+		pm_runtime_put_autosuspend(omap_port->pdev);
+		return -EREMOTEIO;
+	}
+
+	if (msg->ttype == HSI_MSG_READ) {
+		err = dma_map_sg(&ssi->device, msg->sgt.sgl, msg->sgt.nents,
+							DMA_FROM_DEVICE);
+		if (!err) {
+			dev_dbg(&ssi->device, "DMA map SG failed !\n");
+			pm_runtime_put_autosuspend(omap_port->pdev);
+			return -EIO;
+		}
+		csdp = SSI_DST_BURST_4x32_BIT | SSI_DST_MEMORY_PORT |
+			SSI_SRC_SINGLE_ACCESS0 | SSI_SRC_PERIPHERAL_PORT |
+			SSI_DATA_TYPE_S32;
+		ccr = msg->channel + 0x10 + (port->num * 8); /* Sync */
+		ccr |= SSI_DST_AMODE_POSTINC | SSI_SRC_AMODE_CONST |
+			SSI_CCR_ENABLE;
+		s_addr = omap_port->ssr_dma +
+					SSI_SSR_BUFFER_CH_REG(msg->channel);
+		d_addr = sg_dma_address(msg->sgt.sgl);
+	} else {
+		err = dma_map_sg(&ssi->device, msg->sgt.sgl, msg->sgt.nents,
+							DMA_TO_DEVICE);
+		if (!err) {
+			dev_dbg(&ssi->device, "DMA map SG failed !\n");
+			pm_runtime_put_autosuspend(omap_port->pdev);
+			return -EIO;
+		}
+		csdp = SSI_SRC_BURST_4x32_BIT | SSI_SRC_MEMORY_PORT |
+			SSI_DST_SINGLE_ACCESS0 | SSI_DST_PERIPHERAL_PORT |
+			SSI_DATA_TYPE_S32;
+		ccr = (msg->channel + 1 + (port->num * 8)) & 0xf; /* Sync */
+		ccr |= SSI_SRC_AMODE_POSTINC | SSI_DST_AMODE_CONST |
+			SSI_CCR_ENABLE;
+		s_addr = sg_dma_address(msg->sgt.sgl);
+		d_addr = omap_port->sst_dma +
+					SSI_SST_BUFFER_CH_REG(msg->channel);
+	}
+	dev_dbg(&ssi->device, "lch %d cdsp %08x ccr %04x s_addr %08x d_addr %08x\n",
+		lch, csdp, ccr, s_addr, d_addr);
+
+	writew_relaxed(csdp, gdd + SSI_GDD_CSDP_REG(lch));
+	writew_relaxed(SSI_BLOCK_IE | SSI_TOUT_IE, gdd + SSI_GDD_CICR_REG(lch));
+	writel_relaxed(d_addr, gdd + SSI_GDD_CDSA_REG(lch));
+	writel_relaxed(s_addr, gdd + SSI_GDD_CSSA_REG(lch));
+	writew_relaxed(SSI_BYTES_TO_FRAMES(msg->sgt.sgl->length),
+						gdd + SSI_GDD_CEN_REG(lch));
+
+	spin_lock_bh(&omap_ssi->lock);
+	tmp = readl(omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
+	tmp |= SSI_GDD_LCH(lch);
+	writel_relaxed(tmp, omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
+	spin_unlock_bh(&omap_ssi->lock);
+	writew(ccr, gdd + SSI_GDD_CCR_REG(lch));
+	msg->status = HSI_STATUS_PROCEEDING;
+
+	return 0;
+}
+
+static int ssi_start_pio(struct hsi_msg *msg)
+{
+	struct hsi_port *port = hsi_get_port(msg->cl);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	u32 val;
+
+	pm_runtime_get(omap_port->pdev);
+
+	if (!pm_runtime_active(omap_port->pdev)) {
+		dev_warn(&port->device, "ssi_start_pio called without runtime PM!\n");
+		pm_runtime_put_autosuspend(omap_port->pdev);
+		return -EREMOTEIO;
+	}
+
+	if (msg->ttype == HSI_MSG_WRITE) {
+		val = SSI_DATAACCEPT(msg->channel);
+		/* Hold clocks for pio writes */
+		pm_runtime_get(omap_port->pdev);
+	} else {
+		val = SSI_DATAAVAILABLE(msg->channel) | SSI_ERROROCCURED;
+	}
+	dev_dbg(&port->device, "Single %s transfer\n",
+						msg->ttype ? "write" : "read");
+	val |= readl(omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+	writel(val, omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+	pm_runtime_put_autosuspend(omap_port->pdev);
+	msg->actual_len = 0;
+	msg->status = HSI_STATUS_PROCEEDING;
+
+	return 0;
+}
+
+static int ssi_start_transfer(struct list_head *queue)
+{
+	struct hsi_msg *msg;
+	int lch = -1;
+
+	if (list_empty(queue))
+		return 0;
+	msg = list_first_entry(queue, struct hsi_msg, link);
+	if (msg->status != HSI_STATUS_QUEUED)
+		return 0;
+	if ((msg->sgt.nents) && (msg->sgt.sgl->length > sizeof(u32)))
+		lch = ssi_claim_lch(msg);
+	if (lch >= 0)
+		return ssi_start_dma(msg, lch);
+	else
+		return ssi_start_pio(msg);
+}
+
+static int ssi_async_break(struct hsi_msg *msg)
+{
+	struct hsi_port *port = hsi_get_port(msg->cl);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	int err = 0;
+	u32 tmp;
+
+	pm_runtime_get_sync(omap_port->pdev);
+	if (msg->ttype == HSI_MSG_WRITE) {
+		if (omap_port->sst.mode != SSI_MODE_FRAME) {
+			err = -EINVAL;
+			goto out;
+		}
+		writel(1, omap_port->sst_base + SSI_SST_BREAK_REG);
+		msg->status = HSI_STATUS_COMPLETED;
+		msg->complete(msg);
+	} else {
+		if (omap_port->ssr.mode != SSI_MODE_FRAME) {
+			err = -EINVAL;
+			goto out;
+		}
+		spin_lock_bh(&omap_port->lock);
+		tmp = readl(omap_ssi->sys +
+					SSI_MPU_ENABLE_REG(port->num, 0));
+		writel(tmp | SSI_BREAKDETECTED,
+			omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+		msg->status = HSI_STATUS_PROCEEDING;
+		list_add_tail(&msg->link, &omap_port->brkqueue);
+		spin_unlock_bh(&omap_port->lock);
+	}
+out:
+	pm_runtime_mark_last_busy(omap_port->pdev);
+	pm_runtime_put_autosuspend(omap_port->pdev);
+
+	return err;
+}
+
+static int ssi_async(struct hsi_msg *msg)
+{
+	struct hsi_port *port = hsi_get_port(msg->cl);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct list_head *queue;
+	int err = 0;
+
+	BUG_ON(!msg);
+
+	if (msg->sgt.nents > 1)
+		return -ENOSYS; /* TODO: Add sg support */
+
+	if (msg->break_frame)
+		return ssi_async_break(msg);
+
+	if (msg->ttype) {
+		BUG_ON(msg->channel >= omap_port->sst.channels);
+		queue = &omap_port->txqueue[msg->channel];
+	} else {
+		BUG_ON(msg->channel >= omap_port->ssr.channels);
+		queue = &omap_port->rxqueue[msg->channel];
+	}
+	msg->status = HSI_STATUS_QUEUED;
+
+	pm_runtime_get_sync(omap_port->pdev);
+	spin_lock_bh(&omap_port->lock);
+	list_add_tail(&msg->link, queue);
+	err = ssi_start_transfer(queue);
+	if (err < 0) {
+		list_del(&msg->link);
+		msg->status = HSI_STATUS_ERROR;
+	}
+	spin_unlock_bh(&omap_port->lock);
+	pm_runtime_mark_last_busy(omap_port->pdev);
+	pm_runtime_put_autosuspend(omap_port->pdev);
+	dev_dbg(&port->device, "msg status %d ttype %d ch %d\n",
+				msg->status, msg->ttype, msg->channel);
+
+	return err;
+}
+
+static u32 ssi_calculate_div(struct hsi_controller *ssi)
+{
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	u32 tx_fckrate = (u32) omap_ssi->fck_rate;
+
+	/* / 2 : SSI TX clock is always half of the SSI functional clock */
+	tx_fckrate >>= 1;
+	/* Round down when tx_fckrate % omap_ssi->max_speed == 0 */
+	tx_fckrate--;
+	dev_dbg(&ssi->device, "TX div %d for fck_rate %lu Khz speed %d Kb/s\n",
+		tx_fckrate / omap_ssi->max_speed, omap_ssi->fck_rate,
+		omap_ssi->max_speed);
+
+	return tx_fckrate / omap_ssi->max_speed;
+}
+
+static void ssi_flush_queue(struct list_head *queue, struct hsi_client *cl)
+{
+	struct list_head *node, *tmp;
+	struct hsi_msg *msg;
+
+	list_for_each_safe(node, tmp, queue) {
+		msg = list_entry(node, struct hsi_msg, link);
+		if ((cl) && (cl != msg->cl))
+			continue;
+		list_del(node);
+		pr_debug("flush queue: ch %d, msg %p len %d type %d ctxt %p\n",
+			msg->channel, msg, msg->sgt.sgl->length,
+					msg->ttype, msg->context);
+		if (msg->destructor)
+			msg->destructor(msg);
+		else
+			hsi_free_msg(msg);
+	}
+}
+
+static int ssi_setup(struct hsi_client *cl)
+{
+	struct hsi_port *port = to_hsi_port(cl->device.parent);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	void __iomem *sst = omap_port->sst_base;
+	void __iomem *ssr = omap_port->ssr_base;
+	u32 div;
+	u32 val;
+	int err = 0;
+
+	pm_runtime_get_sync(omap_port->pdev);
+	spin_lock_bh(&omap_port->lock);
+	if (cl->tx_cfg.speed)
+		omap_ssi->max_speed = cl->tx_cfg.speed;
+	div = ssi_calculate_div(ssi);
+	if (div > SSI_MAX_DIVISOR) {
+		dev_err(&cl->device, "Invalid TX speed %d Mb/s (div %d)\n",
+						cl->tx_cfg.speed, div);
+		err = -EINVAL;
+		goto out;
+	}
+	/* Set TX/RX module to sleep to stop TX/RX during cfg update */
+	writel_relaxed(SSI_MODE_SLEEP, sst + SSI_SST_MODE_REG);
+	writel_relaxed(SSI_MODE_SLEEP, ssr + SSI_SSR_MODE_REG);
+	/* Flush posted write */
+	val = readl(ssr + SSI_SSR_MODE_REG);
+	/* TX */
+	writel_relaxed(31, sst + SSI_SST_FRAMESIZE_REG);
+	writel_relaxed(div, sst + SSI_SST_DIVISOR_REG);
+	writel_relaxed(cl->tx_cfg.num_hw_channels, sst + SSI_SST_CHANNELS_REG);
+	writel_relaxed(cl->tx_cfg.arb_mode, sst + SSI_SST_ARBMODE_REG);
+	writel_relaxed(cl->tx_cfg.mode, sst + SSI_SST_MODE_REG);
+	/* RX */
+	writel_relaxed(31, ssr + SSI_SSR_FRAMESIZE_REG);
+	writel_relaxed(cl->rx_cfg.num_hw_channels, ssr + SSI_SSR_CHANNELS_REG);
+	writel_relaxed(0, ssr + SSI_SSR_TIMEOUT_REG);
+	/* Cleanup the break queue if we leave FRAME mode */
+	if ((omap_port->ssr.mode == SSI_MODE_FRAME) &&
+		(cl->rx_cfg.mode != SSI_MODE_FRAME))
+		ssi_flush_queue(&omap_port->brkqueue, cl);
+	writel_relaxed(cl->rx_cfg.mode, ssr + SSI_SSR_MODE_REG);
+	omap_port->channels = max(cl->rx_cfg.num_hw_channels,
+				  cl->tx_cfg.num_hw_channels);
+	/* Shadow registering for OFF mode */
+	/* SST */
+	omap_port->sst.divisor = div;
+	omap_port->sst.frame_size = 31;
+	omap_port->sst.channels = cl->tx_cfg.num_hw_channels;
+	omap_port->sst.arb_mode = cl->tx_cfg.arb_mode;
+	omap_port->sst.mode = cl->tx_cfg.mode;
+	/* SSR */
+	omap_port->ssr.frame_size = 31;
+	omap_port->ssr.timeout = 0;
+	omap_port->ssr.channels = cl->rx_cfg.num_hw_channels;
+	omap_port->ssr.mode = cl->rx_cfg.mode;
+out:
+	spin_unlock_bh(&omap_port->lock);
+	pm_runtime_mark_last_busy(omap_port->pdev);
+	pm_runtime_put_autosuspend(omap_port->pdev);
+
+	return err;
+}
+
+static int ssi_flush(struct hsi_client *cl)
+{
+	struct hsi_port *port = hsi_get_port(cl);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	struct hsi_msg *msg;
+	void __iomem *sst = omap_port->sst_base;
+	void __iomem *ssr = omap_port->ssr_base;
+	unsigned int i;
+	u32 err;
+
+	pm_runtime_get_sync(omap_port->pdev);
+	spin_lock_bh(&omap_port->lock);
+
+	/* stop all ssi communication */
+	pinctrl_pm_select_idle_state(omap_port->pdev);
+	udelay(1); /* wait for racing frames */
+
+	/* Stop all DMA transfers */
+	for (i = 0; i < SSI_MAX_GDD_LCH; i++) {
+		msg = omap_ssi->gdd_trn[i].msg;
+		if (!msg || (port != hsi_get_port(msg->cl)))
+			continue;
+		writew_relaxed(0, omap_ssi->gdd + SSI_GDD_CCR_REG(i));
+		if (msg->ttype == HSI_MSG_READ)
+			pm_runtime_put_autosuspend(omap_port->pdev);
+		omap_ssi->gdd_trn[i].msg = NULL;
+	}
+	/* Flush all SST buffers */
+	writel_relaxed(0, sst + SSI_SST_BUFSTATE_REG);
+	writel_relaxed(0, sst + SSI_SST_TXSTATE_REG);
+	/* Flush all SSR buffers */
+	writel_relaxed(0, ssr + SSI_SSR_RXSTATE_REG);
+	writel_relaxed(0, ssr + SSI_SSR_BUFSTATE_REG);
+	/* Flush all errors */
+	err = readl(ssr + SSI_SSR_ERROR_REG);
+	writel_relaxed(err, ssr + SSI_SSR_ERRORACK_REG);
+	/* Flush break */
+	writel_relaxed(0, ssr + SSI_SSR_BREAK_REG);
+	/* Clear interrupts */
+	writel_relaxed(0, omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+	writel_relaxed(0xffffff00,
+			omap_ssi->sys + SSI_MPU_STATUS_REG(port->num, 0));
+	writel_relaxed(0, omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
+	writel(0xff, omap_ssi->sys + SSI_GDD_MPU_IRQ_STATUS_REG);
+	/* Dequeue all pending requests */
+	for (i = 0; i < omap_port->channels; i++) {
+		/* Release write clocks */
+		if (!list_empty(&omap_port->txqueue[i]))
+			pm_runtime_put_autosuspend(omap_port->pdev);
+		ssi_flush_queue(&omap_port->txqueue[i], NULL);
+		ssi_flush_queue(&omap_port->rxqueue[i], NULL);
+	}
+	ssi_flush_queue(&omap_port->brkqueue, NULL);
+
+	/* Resume SSI communication */
+	pinctrl_pm_select_default_state(omap_port->pdev);
+
+	spin_unlock_bh(&omap_port->lock);
+	pm_runtime_mark_last_busy(omap_port->pdev);
+	pm_runtime_put_autosuspend(omap_port->pdev);
+
+	return 0;
+}
+
+static void start_tx_work(struct work_struct *work)
+{
+	struct omap_ssi_port *omap_port =
+				container_of(work, struct omap_ssi_port, work);
+	struct hsi_port *port = to_hsi_port(omap_port->dev);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+
+	pm_runtime_get_sync(omap_port->pdev); /* Grab clocks */
+	writel(SSI_WAKE(0), omap_ssi->sys + SSI_SET_WAKE_REG(port->num));
+}
+
+static int ssi_start_tx(struct hsi_client *cl)
+{
+	struct hsi_port *port = hsi_get_port(cl);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+
+	dev_dbg(&port->device, "Wake out high %d\n", omap_port->wk_refcount);
+
+	spin_lock_bh(&omap_port->wk_lock);
+	if (omap_port->wk_refcount++) {
+		spin_unlock_bh(&omap_port->wk_lock);
+		return 0;
+	}
+	spin_unlock_bh(&omap_port->wk_lock);
+
+	schedule_work(&omap_port->work);
+
+	return 0;
+}
+
+static int ssi_stop_tx(struct hsi_client *cl)
+{
+	struct hsi_port *port = hsi_get_port(cl);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+
+	dev_dbg(&port->device, "Wake out low %d\n", omap_port->wk_refcount);
+
+	spin_lock_bh(&omap_port->wk_lock);
+	BUG_ON(!omap_port->wk_refcount);
+	if (--omap_port->wk_refcount) {
+		spin_unlock_bh(&omap_port->wk_lock);
+		return 0;
+	}
+	writel(SSI_WAKE(0), omap_ssi->sys + SSI_CLEAR_WAKE_REG(port->num));
+	spin_unlock_bh(&omap_port->wk_lock);
+
+	pm_runtime_mark_last_busy(omap_port->pdev);
+	pm_runtime_put_autosuspend(omap_port->pdev); /* Release clocks */
+
+
+	return 0;
+}
+
+static void ssi_transfer(struct omap_ssi_port *omap_port,
+							struct list_head *queue)
+{
+	struct hsi_msg *msg;
+	int err = -1;
+
+	pm_runtime_get(omap_port->pdev);
+	spin_lock_bh(&omap_port->lock);
+	while (err < 0) {
+		err = ssi_start_transfer(queue);
+		if (err < 0) {
+			msg = list_first_entry(queue, struct hsi_msg, link);
+			msg->status = HSI_STATUS_ERROR;
+			msg->actual_len = 0;
+			list_del(&msg->link);
+			spin_unlock_bh(&omap_port->lock);
+			msg->complete(msg);
+			spin_lock_bh(&omap_port->lock);
+		}
+	}
+	spin_unlock_bh(&omap_port->lock);
+	pm_runtime_mark_last_busy(omap_port->pdev);
+	pm_runtime_put_autosuspend(omap_port->pdev);
+}
+
+static void ssi_cleanup_queues(struct hsi_client *cl)
+{
+	struct hsi_port *port = hsi_get_port(cl);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	struct hsi_msg *msg;
+	unsigned int i;
+	u32 rxbufstate = 0;
+	u32 txbufstate = 0;
+	u32 status = SSI_ERROROCCURED;
+	u32 tmp;
+
+	ssi_flush_queue(&omap_port->brkqueue, cl);
+	if (list_empty(&omap_port->brkqueue))
+		status |= SSI_BREAKDETECTED;
+
+	for (i = 0; i < omap_port->channels; i++) {
+		if (list_empty(&omap_port->txqueue[i]))
+			continue;
+		msg = list_first_entry(&omap_port->txqueue[i], struct hsi_msg,
+									link);
+		if ((msg->cl == cl) && (msg->status == HSI_STATUS_PROCEEDING)) {
+			txbufstate |= (1 << i);
+			status |= SSI_DATAACCEPT(i);
+			/* Release the clocks writes, also GDD ones */
+			pm_runtime_mark_last_busy(omap_port->pdev);
+			pm_runtime_put_autosuspend(omap_port->pdev);
+		}
+		ssi_flush_queue(&omap_port->txqueue[i], cl);
+	}
+	for (i = 0; i < omap_port->channels; i++) {
+		if (list_empty(&omap_port->rxqueue[i]))
+			continue;
+		msg = list_first_entry(&omap_port->rxqueue[i], struct hsi_msg,
+									link);
+		if ((msg->cl == cl) && (msg->status == HSI_STATUS_PROCEEDING)) {
+			rxbufstate |= (1 << i);
+			status |= SSI_DATAAVAILABLE(i);
+		}
+		ssi_flush_queue(&omap_port->rxqueue[i], cl);
+		/* Check if we keep the error detection interrupt armed */
+		if (!list_empty(&omap_port->rxqueue[i]))
+			status &= ~SSI_ERROROCCURED;
+	}
+	/* Cleanup write buffers */
+	tmp = readl(omap_port->sst_base + SSI_SST_BUFSTATE_REG);
+	tmp &= ~txbufstate;
+	writel_relaxed(tmp, omap_port->sst_base + SSI_SST_BUFSTATE_REG);
+	/* Cleanup read buffers */
+	tmp = readl(omap_port->ssr_base + SSI_SSR_BUFSTATE_REG);
+	tmp &= ~rxbufstate;
+	writel_relaxed(tmp, omap_port->ssr_base + SSI_SSR_BUFSTATE_REG);
+	/* Disarm and ack pending interrupts */
+	tmp = readl(omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+	tmp &= ~status;
+	writel_relaxed(tmp, omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+	writel_relaxed(status, omap_ssi->sys +
+		SSI_MPU_STATUS_REG(port->num, 0));
+}
+
+static void ssi_cleanup_gdd(struct hsi_controller *ssi, struct hsi_client *cl)
+{
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	struct hsi_port *port = hsi_get_port(cl);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_msg *msg;
+	unsigned int i;
+	u32 val = 0;
+	u32 tmp;
+
+	for (i = 0; i < SSI_MAX_GDD_LCH; i++) {
+		msg = omap_ssi->gdd_trn[i].msg;
+		if ((!msg) || (msg->cl != cl))
+			continue;
+		writew_relaxed(0, omap_ssi->gdd + SSI_GDD_CCR_REG(i));
+		val |= (1 << i);
+		/*
+		 * Clock references for write will be handled in
+		 * ssi_cleanup_queues
+		 */
+		if (msg->ttype == HSI_MSG_READ) {
+			pm_runtime_mark_last_busy(omap_port->pdev);
+			pm_runtime_put_autosuspend(omap_port->pdev);
+		}
+		omap_ssi->gdd_trn[i].msg = NULL;
+	}
+	tmp = readl_relaxed(omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
+	tmp &= ~val;
+	writel_relaxed(tmp, omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
+	writel(val, omap_ssi->sys + SSI_GDD_MPU_IRQ_STATUS_REG);
+}
+
+static int ssi_set_port_mode(struct omap_ssi_port *omap_port, u32 mode)
+{
+	writel(mode, omap_port->sst_base + SSI_SST_MODE_REG);
+	writel(mode, omap_port->ssr_base + SSI_SSR_MODE_REG);
+	/* OCP barrier */
+	mode = readl(omap_port->ssr_base + SSI_SSR_MODE_REG);
+
+	return 0;
+}
+
+static int ssi_release(struct hsi_client *cl)
+{
+	struct hsi_port *port = hsi_get_port(cl);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+
+	pm_runtime_get_sync(omap_port->pdev);
+	spin_lock_bh(&omap_port->lock);
+	/* Stop all the pending DMA requests for that client */
+	ssi_cleanup_gdd(ssi, cl);
+	/* Now cleanup all the queues */
+	ssi_cleanup_queues(cl);
+	/* If it is the last client of the port, do extra checks and cleanup */
+	if (port->claimed <= 1) {
+		/*
+		 * Drop the clock reference for the incoming wake line
+		 * if it is still kept high by the other side.
+		 */
+		if (test_and_clear_bit(SSI_WAKE_EN, &omap_port->flags))
+			pm_runtime_put_sync(omap_port->pdev);
+		pm_runtime_get(omap_port->pdev);
+		/* Stop any SSI TX/RX without a client */
+		ssi_set_port_mode(omap_port, SSI_MODE_SLEEP);
+		omap_port->sst.mode = SSI_MODE_SLEEP;
+		omap_port->ssr.mode = SSI_MODE_SLEEP;
+		pm_runtime_put(omap_port->pdev);
+		WARN_ON(omap_port->wk_refcount != 0);
+	}
+	spin_unlock_bh(&omap_port->lock);
+	pm_runtime_put_sync(omap_port->pdev);
+
+	return 0;
+}
+
+
+
+static void ssi_error(struct hsi_port *port)
+{
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	struct hsi_msg *msg;
+	unsigned int i;
+	u32 err;
+	u32 val;
+	u32 tmp;
+
+	/* ACK error */
+	err = readl(omap_port->ssr_base + SSI_SSR_ERROR_REG);
+	dev_err(&port->device, "SSI error: 0x%02x\n", err);
+	if (!err) {
+		dev_dbg(&port->device, "spurious SSI error ignored!\n");
+		return;
+	}
+	spin_lock(&omap_ssi->lock);
+	/* Cancel all GDD read transfers */
+	for (i = 0, val = 0; i < SSI_MAX_GDD_LCH; i++) {
+		msg = omap_ssi->gdd_trn[i].msg;
+		if ((msg) && (msg->ttype == HSI_MSG_READ)) {
+			writew_relaxed(0, omap_ssi->gdd + SSI_GDD_CCR_REG(i));
+			val |= (1 << i);
+			omap_ssi->gdd_trn[i].msg = NULL;
+		}
+	}
+	tmp = readl(omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
+	tmp &= ~val;
+	writel_relaxed(tmp, omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
+	spin_unlock(&omap_ssi->lock);
+	/* Cancel all PIO read transfers */
+	spin_lock(&omap_port->lock);
+	tmp = readl(omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+	tmp &= 0xfeff00ff; /* Disable error & all dataavailable interrupts */
+	writel_relaxed(tmp, omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+	/* ACK error */
+	writel_relaxed(err, omap_port->ssr_base + SSI_SSR_ERRORACK_REG);
+	writel_relaxed(SSI_ERROROCCURED,
+			omap_ssi->sys + SSI_MPU_STATUS_REG(port->num, 0));
+	/* Signal the error all current pending read requests */
+	for (i = 0; i < omap_port->channels; i++) {
+		if (list_empty(&omap_port->rxqueue[i]))
+			continue;
+		msg = list_first_entry(&omap_port->rxqueue[i], struct hsi_msg,
+									link);
+		list_del(&msg->link);
+		msg->status = HSI_STATUS_ERROR;
+		spin_unlock(&omap_port->lock);
+		msg->complete(msg);
+		/* Now restart queued reads if any */
+		ssi_transfer(omap_port, &omap_port->rxqueue[i]);
+		spin_lock(&omap_port->lock);
+	}
+	spin_unlock(&omap_port->lock);
+}
+
+static void ssi_break_complete(struct hsi_port *port)
+{
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	struct hsi_msg *msg;
+	struct hsi_msg *tmp;
+	u32 val;
+
+	dev_dbg(&port->device, "HWBREAK received\n");
+
+	spin_lock(&omap_port->lock);
+	val = readl(omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+	val &= ~SSI_BREAKDETECTED;
+	writel_relaxed(val, omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+	writel_relaxed(0, omap_port->ssr_base + SSI_SSR_BREAK_REG);
+	writel(SSI_BREAKDETECTED,
+			omap_ssi->sys + SSI_MPU_STATUS_REG(port->num, 0));
+	spin_unlock(&omap_port->lock);
+
+	list_for_each_entry_safe(msg, tmp, &omap_port->brkqueue, link) {
+		msg->status = HSI_STATUS_COMPLETED;
+		spin_lock(&omap_port->lock);
+		list_del(&msg->link);
+		spin_unlock(&omap_port->lock);
+		msg->complete(msg);
+	}
+
+}
+
+static void ssi_pio_complete(struct hsi_port *port, struct list_head *queue)
+{
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_msg *msg;
+	u32 *buf;
+	u32 reg;
+	u32 val;
+
+	spin_lock_bh(&omap_port->lock);
+	msg = list_first_entry(queue, struct hsi_msg, link);
+	if ((!msg->sgt.nents) || (!msg->sgt.sgl->length)) {
+		msg->actual_len = 0;
+		msg->status = HSI_STATUS_PENDING;
+	}
+	if (msg->ttype == HSI_MSG_WRITE)
+		val = SSI_DATAACCEPT(msg->channel);
+	else
+		val = SSI_DATAAVAILABLE(msg->channel);
+	if (msg->status == HSI_STATUS_PROCEEDING) {
+		buf = sg_virt(msg->sgt.sgl) + msg->actual_len;
+		if (msg->ttype == HSI_MSG_WRITE)
+			writel(*buf, omap_port->sst_base +
+					SSI_SST_BUFFER_CH_REG(msg->channel));
+		 else
+			*buf = readl(omap_port->ssr_base +
+					SSI_SSR_BUFFER_CH_REG(msg->channel));
+		dev_dbg(&port->device, "ch %d ttype %d 0x%08x\n", msg->channel,
+							msg->ttype, *buf);
+		msg->actual_len += sizeof(*buf);
+		if (msg->actual_len >= msg->sgt.sgl->length)
+			msg->status = HSI_STATUS_COMPLETED;
+		/*
+		 * Wait for the last written frame to be really sent before
+		 * we call the complete callback
+		 */
+		if ((msg->status == HSI_STATUS_PROCEEDING) ||
+				((msg->status == HSI_STATUS_COMPLETED) &&
+					(msg->ttype == HSI_MSG_WRITE))) {
+			writel(val, omap_ssi->sys +
+					SSI_MPU_STATUS_REG(port->num, 0));
+			spin_unlock_bh(&omap_port->lock);
+
+			return;
+		}
+
+	}
+	/* Transfer completed at this point */
+	reg = readl(omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+	if (msg->ttype == HSI_MSG_WRITE) {
+		/* Release clocks for write transfer */
+		pm_runtime_mark_last_busy(omap_port->pdev);
+		pm_runtime_put_autosuspend(omap_port->pdev);
+	}
+	reg &= ~val;
+	writel_relaxed(reg, omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+	writel_relaxed(val, omap_ssi->sys + SSI_MPU_STATUS_REG(port->num, 0));
+	list_del(&msg->link);
+	spin_unlock_bh(&omap_port->lock);
+	msg->complete(msg);
+	ssi_transfer(omap_port, queue);
+}
+
+static irqreturn_t ssi_pio_thread(int irq, void *ssi_port)
+{
+	struct hsi_port *port = (struct hsi_port *)ssi_port;
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	void __iomem *sys = omap_ssi->sys;
+	unsigned int ch;
+	u32 status_reg;
+
+	pm_runtime_get_sync(omap_port->pdev);
+
+	do {
+		status_reg = readl(sys + SSI_MPU_STATUS_REG(port->num, 0));
+		status_reg &= readl(sys + SSI_MPU_ENABLE_REG(port->num, 0));
+
+		for (ch = 0; ch < omap_port->channels; ch++) {
+			if (status_reg & SSI_DATAACCEPT(ch))
+				ssi_pio_complete(port, &omap_port->txqueue[ch]);
+			if (status_reg & SSI_DATAAVAILABLE(ch))
+				ssi_pio_complete(port, &omap_port->rxqueue[ch]);
+		}
+		if (status_reg & SSI_BREAKDETECTED)
+			ssi_break_complete(port);
+		if (status_reg & SSI_ERROROCCURED)
+			ssi_error(port);
+
+		status_reg = readl(sys + SSI_MPU_STATUS_REG(port->num, 0));
+		status_reg &= readl(sys + SSI_MPU_ENABLE_REG(port->num, 0));
+
+		/* TODO: sleep if we retry? */
+	} while (status_reg);
+
+	pm_runtime_mark_last_busy(omap_port->pdev);
+	pm_runtime_put_autosuspend(omap_port->pdev);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t ssi_wake_thread(int irq __maybe_unused, void *ssi_port)
+{
+	struct hsi_port *port = (struct hsi_port *)ssi_port;
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+
+	if (ssi_wakein(port)) {
+		/**
+		 * We can have a quick High-Low-High transition in the line.
+		 * In such a case if we have long interrupt latencies,
+		 * we can miss the low event or get twice a high event.
+		 * This workaround will avoid breaking the clock reference
+		 * count when such a situation ocurrs.
+		 */
+		if (!test_and_set_bit(SSI_WAKE_EN, &omap_port->flags))
+			pm_runtime_get_sync(omap_port->pdev);
+		dev_dbg(&ssi->device, "Wake in high\n");
+		if (omap_port->wktest) { /* FIXME: HACK ! To be removed */
+			writel(SSI_WAKE(0),
+				omap_ssi->sys + SSI_SET_WAKE_REG(port->num));
+		}
+		hsi_event(port, HSI_EVENT_START_RX);
+	} else {
+		dev_dbg(&ssi->device, "Wake in low\n");
+		if (omap_port->wktest) { /* FIXME: HACK ! To be removed */
+			writel(SSI_WAKE(0),
+				omap_ssi->sys + SSI_CLEAR_WAKE_REG(port->num));
+		}
+		hsi_event(port, HSI_EVENT_STOP_RX);
+		if (test_and_clear_bit(SSI_WAKE_EN, &omap_port->flags)) {
+			pm_runtime_mark_last_busy(omap_port->pdev);
+			pm_runtime_put_autosuspend(omap_port->pdev);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int ssi_port_irq(struct hsi_port *port, struct platform_device *pd)
+{
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	int err;
+
+	err = platform_get_irq(pd, 0);
+	if (err < 0)
+		return err;
+	omap_port->irq = err;
+	err = devm_request_threaded_irq(&port->device, omap_port->irq, NULL,
+				ssi_pio_thread, IRQF_ONESHOT, "SSI PORT", port);
+	if (err < 0)
+		dev_err(&port->device, "Request IRQ %d failed (%d)\n",
+							omap_port->irq, err);
+	return err;
+}
+
+static int ssi_wake_irq(struct hsi_port *port, struct platform_device *pd)
+{
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	int cawake_irq;
+	int err;
+
+	if (!omap_port->wake_gpio) {
+		omap_port->wake_irq = -1;
+		return 0;
+	}
+
+	cawake_irq = gpiod_to_irq(omap_port->wake_gpio);
+	omap_port->wake_irq = cawake_irq;
+
+	err = devm_request_threaded_irq(&port->device, cawake_irq, NULL,
+		ssi_wake_thread,
+		IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+		"SSI cawake", port);
+	if (err < 0)
+		dev_err(&port->device, "Request Wake in IRQ %d failed %d\n",
+						cawake_irq, err);
+	err = enable_irq_wake(cawake_irq);
+	if (err < 0)
+		dev_err(&port->device, "Enable wake on the wakeline in irq %d failed %d\n",
+			cawake_irq, err);
+
+	return err;
+}
+
+static void ssi_queues_init(struct omap_ssi_port *omap_port)
+{
+	unsigned int ch;
+
+	for (ch = 0; ch < SSI_MAX_CHANNELS; ch++) {
+		INIT_LIST_HEAD(&omap_port->txqueue[ch]);
+		INIT_LIST_HEAD(&omap_port->rxqueue[ch]);
+	}
+	INIT_LIST_HEAD(&omap_port->brkqueue);
+}
+
+static int ssi_port_get_iomem(struct platform_device *pd,
+		const char *name, void __iomem **pbase, dma_addr_t *phy)
+{
+	struct hsi_port *port = platform_get_drvdata(pd);
+	struct resource *mem;
+	struct resource *ioarea;
+	void __iomem *base;
+
+	mem = platform_get_resource_byname(pd, IORESOURCE_MEM, name);
+	if (!mem) {
+		dev_err(&pd->dev, "IO memory region missing (%s)\n", name);
+		return -ENXIO;
+	}
+	ioarea = devm_request_mem_region(&port->device, mem->start,
+					resource_size(mem), dev_name(&pd->dev));
+	if (!ioarea) {
+		dev_err(&pd->dev, "%s IO memory region request failed\n",
+								mem->name);
+		return -ENXIO;
+	}
+	base = devm_ioremap(&port->device, mem->start, resource_size(mem));
+	if (!base) {
+		dev_err(&pd->dev, "%s IO remap failed\n", mem->name);
+		return -ENXIO;
+	}
+	*pbase = base;
+
+	if (phy)
+		*phy = mem->start;
+
+	return 0;
+}
+
+static int ssi_port_probe(struct platform_device *pd)
+{
+	struct device_node *np = pd->dev.of_node;
+	struct hsi_port *port;
+	struct omap_ssi_port *omap_port;
+	struct hsi_controller *ssi = dev_get_drvdata(pd->dev.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	struct gpio_desc *cawake_gpio = NULL;
+	u32 port_id;
+	int err;
+
+	dev_dbg(&pd->dev, "init ssi port...\n");
+
+	if (!ssi->port || !omap_ssi->port) {
+		dev_err(&pd->dev, "ssi controller not initialized!\n");
+		err = -ENODEV;
+		goto error;
+	}
+
+	/* get id of first uninitialized port in controller */
+	for (port_id = 0; port_id < ssi->num_ports && omap_ssi->port[port_id];
+		port_id++)
+		;
+
+	if (port_id >= ssi->num_ports) {
+		dev_err(&pd->dev, "port id out of range!\n");
+		err = -ENODEV;
+		goto error;
+	}
+
+	port = ssi->port[port_id];
+
+	if (!np) {
+		dev_err(&pd->dev, "missing device tree data\n");
+		err = -EINVAL;
+		goto error;
+	}
+
+	cawake_gpio = devm_gpiod_get(&pd->dev, "ti,ssi-cawake", GPIOD_IN);
+	if (IS_ERR(cawake_gpio)) {
+		err = PTR_ERR(cawake_gpio);
+		dev_err(&pd->dev, "couldn't get cawake gpio (err=%d)!\n", err);
+		goto error;
+	}
+
+	omap_port = devm_kzalloc(&port->device, sizeof(*omap_port), GFP_KERNEL);
+	if (!omap_port) {
+		err = -ENOMEM;
+		goto error;
+	}
+	omap_port->wake_gpio = cawake_gpio;
+	omap_port->pdev = &pd->dev;
+	omap_port->port_id = port_id;
+
+	INIT_DEFERRABLE_WORK(&omap_port->errqueue_work, ssi_process_errqueue);
+	INIT_WORK(&omap_port->work, start_tx_work);
+
+	/* initialize HSI port */
+	port->async	= ssi_async;
+	port->setup	= ssi_setup;
+	port->flush	= ssi_flush;
+	port->start_tx	= ssi_start_tx;
+	port->stop_tx	= ssi_stop_tx;
+	port->release	= ssi_release;
+	hsi_port_set_drvdata(port, omap_port);
+	omap_ssi->port[port_id] = omap_port;
+
+	platform_set_drvdata(pd, port);
+
+	err = ssi_port_get_iomem(pd, "tx", &omap_port->sst_base,
+		&omap_port->sst_dma);
+	if (err < 0)
+		goto error;
+	err = ssi_port_get_iomem(pd, "rx", &omap_port->ssr_base,
+		&omap_port->ssr_dma);
+	if (err < 0)
+		goto error;
+
+	err = ssi_port_irq(port, pd);
+	if (err < 0)
+		goto error;
+	err = ssi_wake_irq(port, pd);
+	if (err < 0)
+		goto error;
+
+	ssi_queues_init(omap_port);
+	spin_lock_init(&omap_port->lock);
+	spin_lock_init(&omap_port->wk_lock);
+	omap_port->dev = &port->device;
+
+	pm_runtime_use_autosuspend(omap_port->pdev);
+	pm_runtime_set_autosuspend_delay(omap_port->pdev, 250);
+	pm_runtime_enable(omap_port->pdev);
+
+#ifdef CONFIG_DEBUG_FS
+	err = ssi_debug_add_port(omap_port, omap_ssi->dir);
+	if (err < 0) {
+		pm_runtime_disable(omap_port->pdev);
+		goto error;
+	}
+#endif
+
+	hsi_add_clients_from_dt(port, np);
+
+	dev_info(&pd->dev, "ssi port %u successfully initialized\n", port_id);
+
+	return 0;
+
+error:
+	return err;
+}
+
+static int ssi_port_remove(struct platform_device *pd)
+{
+	struct hsi_port *port = platform_get_drvdata(pd);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+
+#ifdef CONFIG_DEBUG_FS
+	ssi_debug_remove_port(port);
+#endif
+
+	cancel_delayed_work_sync(&omap_port->errqueue_work);
+
+	hsi_port_unregister_clients(port);
+
+	port->async	= hsi_dummy_msg;
+	port->setup	= hsi_dummy_cl;
+	port->flush	= hsi_dummy_cl;
+	port->start_tx	= hsi_dummy_cl;
+	port->stop_tx	= hsi_dummy_cl;
+	port->release	= hsi_dummy_cl;
+
+	omap_ssi->port[omap_port->port_id] = NULL;
+	platform_set_drvdata(pd, NULL);
+
+	pm_runtime_dont_use_autosuspend(&pd->dev);
+	pm_runtime_disable(&pd->dev);
+
+	return 0;
+}
+
+static int ssi_restore_divisor(struct omap_ssi_port *omap_port)
+{
+	writel_relaxed(omap_port->sst.divisor,
+				omap_port->sst_base + SSI_SST_DIVISOR_REG);
+
+	return 0;
+}
+
+void omap_ssi_port_update_fclk(struct hsi_controller *ssi,
+			       struct omap_ssi_port *omap_port)
+{
+	/* update divisor */
+	u32 div = ssi_calculate_div(ssi);
+	omap_port->sst.divisor = div;
+	ssi_restore_divisor(omap_port);
+}
+
+#ifdef CONFIG_PM
+static int ssi_save_port_ctx(struct omap_ssi_port *omap_port)
+{
+	struct hsi_port *port = to_hsi_port(omap_port->dev);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+
+	omap_port->sys_mpu_enable = readl(omap_ssi->sys +
+					SSI_MPU_ENABLE_REG(port->num, 0));
+
+	return 0;
+}
+
+static int ssi_restore_port_ctx(struct omap_ssi_port *omap_port)
+{
+	struct hsi_port *port = to_hsi_port(omap_port->dev);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+	void __iomem	*base;
+
+	writel_relaxed(omap_port->sys_mpu_enable,
+			omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
+
+	/* SST context */
+	base = omap_port->sst_base;
+	writel_relaxed(omap_port->sst.frame_size, base + SSI_SST_FRAMESIZE_REG);
+	writel_relaxed(omap_port->sst.channels, base + SSI_SST_CHANNELS_REG);
+	writel_relaxed(omap_port->sst.arb_mode, base + SSI_SST_ARBMODE_REG);
+
+	/* SSR context */
+	base = omap_port->ssr_base;
+	writel_relaxed(omap_port->ssr.frame_size, base + SSI_SSR_FRAMESIZE_REG);
+	writel_relaxed(omap_port->ssr.channels, base + SSI_SSR_CHANNELS_REG);
+	writel_relaxed(omap_port->ssr.timeout, base + SSI_SSR_TIMEOUT_REG);
+
+	return 0;
+}
+
+static int ssi_restore_port_mode(struct omap_ssi_port *omap_port)
+{
+	u32 mode;
+
+	writel_relaxed(omap_port->sst.mode,
+				omap_port->sst_base + SSI_SST_MODE_REG);
+	writel_relaxed(omap_port->ssr.mode,
+				omap_port->ssr_base + SSI_SSR_MODE_REG);
+	/* OCP barrier */
+	mode = readl(omap_port->ssr_base + SSI_SSR_MODE_REG);
+
+	return 0;
+}
+
+static int omap_ssi_port_runtime_suspend(struct device *dev)
+{
+	struct hsi_port *port = dev_get_drvdata(dev);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+
+	dev_dbg(dev, "port runtime suspend!\n");
+
+	ssi_set_port_mode(omap_port, SSI_MODE_SLEEP);
+	if (omap_ssi->get_loss)
+		omap_port->loss_count =
+				omap_ssi->get_loss(ssi->device.parent);
+	ssi_save_port_ctx(omap_port);
+
+	return 0;
+}
+
+static int omap_ssi_port_runtime_resume(struct device *dev)
+{
+	struct hsi_port *port = dev_get_drvdata(dev);
+	struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
+	struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
+	struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
+
+	dev_dbg(dev, "port runtime resume!\n");
+
+	if ((omap_ssi->get_loss) && (omap_port->loss_count ==
+				omap_ssi->get_loss(ssi->device.parent)))
+		goto mode; /* We always need to restore the mode & TX divisor */
+
+	ssi_restore_port_ctx(omap_port);
+
+mode:
+	ssi_restore_divisor(omap_port);
+	ssi_restore_port_mode(omap_port);
+
+	return 0;
+}
+
+static const struct dev_pm_ops omap_ssi_port_pm_ops = {
+	SET_RUNTIME_PM_OPS(omap_ssi_port_runtime_suspend,
+		omap_ssi_port_runtime_resume, NULL)
+};
+
+#define DEV_PM_OPS     (&omap_ssi_port_pm_ops)
+#else
+#define DEV_PM_OPS     NULL
+#endif
+
+
+#ifdef CONFIG_OF
+static const struct of_device_id omap_ssi_port_of_match[] = {
+	{ .compatible = "ti,omap3-ssi-port", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, omap_ssi_port_of_match);
+#else
+#define omap_ssi_port_of_match NULL
+#endif
+
+struct platform_driver ssi_port_pdriver = {
+	.probe = ssi_port_probe,
+	.remove	= ssi_port_remove,
+	.driver	= {
+		.name	= "omap_ssi_port",
+		.of_match_table = omap_ssi_port_of_match,
+		.pm	= DEV_PM_OPS,
+	},
+};
diff --git a/drivers/hsi/controllers/omap_ssi_regs.h b/drivers/hsi/controllers/omap_ssi_regs.h
new file mode 100644
index 000000000..87000e7da
--- /dev/null
+++ b/drivers/hsi/controllers/omap_ssi_regs.h
@@ -0,0 +1,158 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Hardware definitions for SSI.
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ *
+ * Contact: Carlos Chinea <carlos.chinea@nokia.com>
+ */
+
+#ifndef __OMAP_SSI_REGS_H__
+#define __OMAP_SSI_REGS_H__
+
+/*
+ * SSI SYS registers
+ */
+#define SSI_REVISION_REG    0
+#  define SSI_REV_MAJOR    0xf0
+#  define SSI_REV_MINOR    0xf
+#define SSI_SYSCONFIG_REG    0x10
+#  define SSI_AUTOIDLE    (1 << 0)
+#  define SSI_SOFTRESET    (1 << 1)
+#  define SSI_SIDLEMODE_FORCE  0
+#  define SSI_SIDLEMODE_NO    (1 << 3)
+#  define SSI_SIDLEMODE_SMART  (1 << 4)
+#  define SSI_SIDLEMODE_MASK  0x18
+#  define SSI_MIDLEMODE_FORCE  0
+#  define SSI_MIDLEMODE_NO    (1 << 12)
+#  define SSI_MIDLEMODE_SMART  (1 << 13)
+#  define SSI_MIDLEMODE_MASK  0x3000
+#define SSI_SYSSTATUS_REG    0x14
+#  define SSI_RESETDONE    1
+#define SSI_MPU_STATUS_REG(port, irq)  (0x808 + ((port) * 0x10) + ((irq) * 2))
+#define SSI_MPU_ENABLE_REG(port, irq)  (0x80c + ((port) * 0x10) + ((irq) * 8))
+#  define SSI_DATAACCEPT(channel)    (1 << (channel))
+#  define SSI_DATAAVAILABLE(channel)  (1 << ((channel) + 8))
+#  define SSI_DATAOVERRUN(channel)    (1 << ((channel) + 16))
+#  define SSI_ERROROCCURED      (1 << 24)
+#  define SSI_BREAKDETECTED    (1 << 25)
+#define SSI_GDD_MPU_IRQ_STATUS_REG  0x0800
+#define SSI_GDD_MPU_IRQ_ENABLE_REG  0x0804
+#  define SSI_GDD_LCH(channel)  (1 << (channel))
+#define SSI_WAKE_REG(port)    (0xc00 + ((port) * 0x10))
+#define SSI_CLEAR_WAKE_REG(port)  (0xc04 + ((port) * 0x10))
+#define SSI_SET_WAKE_REG(port)    (0xc08 + ((port) * 0x10))
+#  define SSI_WAKE(channel)  (1 << (channel))
+#  define SSI_WAKE_MASK    0xff
+
+/*
+ * SSI SST registers
+ */
+#define SSI_SST_ID_REG      0
+#define SSI_SST_MODE_REG    4
+#  define SSI_MODE_VAL_MASK  3
+#  define SSI_MODE_SLEEP    0
+#  define SSI_MODE_STREAM    1
+#  define SSI_MODE_FRAME    2
+#  define SSI_MODE_MULTIPOINTS  3
+#define SSI_SST_FRAMESIZE_REG    8
+#  define SSI_FRAMESIZE_DEFAULT  31
+#define SSI_SST_TXSTATE_REG    0xc
+#  define  SSI_TXSTATE_IDLE  0
+#define SSI_SST_BUFSTATE_REG    0x10
+#  define  SSI_FULL(channel)  (1 << (channel))
+#define SSI_SST_DIVISOR_REG    0x18
+#  define SSI_MAX_DIVISOR    127
+#define SSI_SST_BREAK_REG    0x20
+#define SSI_SST_CHANNELS_REG    0x24
+#  define SSI_CHANNELS_DEFAULT  4
+#define SSI_SST_ARBMODE_REG    0x28
+#  define SSI_ARBMODE_ROUNDROBIN  0
+#  define SSI_ARBMODE_PRIORITY  1
+#define SSI_SST_BUFFER_CH_REG(channel)  (0x80 + ((channel) * 4))
+#define SSI_SST_SWAPBUF_CH_REG(channel)  (0xc0 + ((channel) * 4))
+
+/*
+ * SSI SSR registers
+ */
+#define SSI_SSR_ID_REG      0
+#define SSI_SSR_MODE_REG    4
+#define SSI_SSR_FRAMESIZE_REG    8
+#define SSI_SSR_RXSTATE_REG    0xc
+#define SSI_SSR_BUFSTATE_REG    0x10
+#  define SSI_NOTEMPTY(channel)  (1 << (channel))
+#define SSI_SSR_BREAK_REG    0x1c
+#define SSI_SSR_ERROR_REG    0x20
+#define SSI_SSR_ERRORACK_REG    0x24
+#define SSI_SSR_OVERRUN_REG    0x2c
+#define SSI_SSR_OVERRUNACK_REG    0x30
+#define SSI_SSR_TIMEOUT_REG    0x34
+#  define SSI_TIMEOUT_DEFAULT  0
+#define SSI_SSR_CHANNELS_REG    0x28
+#define SSI_SSR_BUFFER_CH_REG(channel)  (0x80 + ((channel) * 4))
+#define SSI_SSR_SWAPBUF_CH_REG(channel)  (0xc0 + ((channel) * 4))
+
+/*
+ * SSI GDD registers
+ */
+#define SSI_GDD_HW_ID_REG    0
+#define SSI_GDD_PPORT_ID_REG    0x10
+#define SSI_GDD_MPORT_ID_REG    0x14
+#define SSI_GDD_PPORT_SR_REG    0x20
+#define SSI_GDD_MPORT_SR_REG    0x24
+#  define SSI_ACTIVE_LCH_NUM_MASK  0xff
+#define SSI_GDD_TEST_REG    0x40
+#  define SSI_TEST      1
+#define SSI_GDD_GCR_REG      0x100
+#  define  SSI_CLK_AUTOGATING_ON  (1 << 3)
+#  define  SSI_FREE    (1 << 2)
+#  define  SSI_SWITCH_OFF    (1 << 0)
+#define SSI_GDD_GRST_REG    0x200
+#  define SSI_SWRESET    1
+#define SSI_GDD_CSDP_REG(channel)  (0x800 + ((channel) * 0x40))
+#  define SSI_DST_BURST_EN_MASK  0xc000
+#  define SSI_DST_SINGLE_ACCESS0  0
+#  define SSI_DST_SINGLE_ACCESS  (1 << 14)
+#  define SSI_DST_BURST_4x32_BIT  (2 << 14)
+#  define SSI_DST_BURST_8x32_BIT  (3 << 14)
+#  define SSI_DST_MASK    0x1e00
+#  define SSI_DST_MEMORY_PORT  (8 << 9)
+#  define SSI_DST_PERIPHERAL_PORT  (9 << 9)
+#  define SSI_SRC_BURST_EN_MASK  0x180
+#  define SSI_SRC_SINGLE_ACCESS0  0
+#  define SSI_SRC_SINGLE_ACCESS  (1 << 7)
+#  define SSI_SRC_BURST_4x32_BIT  (2 << 7)
+#  define SSI_SRC_BURST_8x32_BIT  (3 << 7)
+#  define SSI_SRC_MASK    0x3c
+#  define SSI_SRC_MEMORY_PORT  (8 << 2)
+#  define SSI_SRC_PERIPHERAL_PORT  (9 << 2)
+#  define SSI_DATA_TYPE_MASK  3
+#  define SSI_DATA_TYPE_S32  2
+#define SSI_GDD_CCR_REG(channel)  (0x802 + ((channel) * 0x40))
+#  define SSI_DST_AMODE_MASK  (3 << 14)
+#  define SSI_DST_AMODE_CONST  0
+#  define SSI_DST_AMODE_POSTINC  (1 << 12)
+#  define SSI_SRC_AMODE_MASK  (3 << 12)
+#  define SSI_SRC_AMODE_CONST  0
+#  define SSI_SRC_AMODE_POSTINC  (1 << 12)
+#  define SSI_CCR_ENABLE    (1 << 7)
+#  define SSI_CCR_SYNC_MASK  0x1f
+#define SSI_GDD_CICR_REG(channel)  (0x804 + ((channel) * 0x40))
+#  define SSI_BLOCK_IE    (1 << 5)
+#  define SSI_HALF_IE    (1 << 2)
+#  define SSI_TOUT_IE    (1 << 0)
+#define SSI_GDD_CSR_REG(channel)  (0x806 + ((channel) * 0x40))
+#  define SSI_CSR_SYNC    (1 << 6)
+#  define SSI_CSR_BLOCK    (1 << 5)
+#  define SSI_CSR_HALF    (1 << 2)
+#  define SSI_CSR_TOUR    (1 << 0)
+#define SSI_GDD_CSSA_REG(channel)  (0x808 + ((channel) * 0x40))
+#define SSI_GDD_CDSA_REG(channel)  (0x80c + ((channel) * 0x40))
+#define SSI_GDD_CEN_REG(channel)  (0x810 + ((channel) * 0x40))
+#define SSI_GDD_CSAC_REG(channel)  (0x818 + ((channel) * 0x40))
+#define SSI_GDD_CDAC_REG(channel)  (0x81a + ((channel) * 0x40))
+#define SSI_GDD_CLNK_CTRL_REG(channel)  (0x828 + ((channel) * 0x40))
+#  define SSI_ENABLE_LNK    (1 << 15)
+#  define SSI_STOP_LNK    (1 << 14)
+#  define SSI_NEXT_CH_ID_MASK  0xf
+
+#endif /* __OMAP_SSI_REGS_H__ */
diff --git a/drivers/hsi/hsi_boardinfo.c b/drivers/hsi/hsi_boardinfo.c
new file mode 100644
index 000000000..52500e7fd
--- /dev/null
+++ b/drivers/hsi/hsi_boardinfo.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HSI clients registration interface
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ *
+ * Contact: Carlos Chinea <carlos.chinea@nokia.com>
+ */
+#include <linux/hsi/hsi.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include "hsi_core.h"
+
+/*
+ * hsi_board_list is only used internally by the HSI framework.
+ * No one else is allowed to make use of it.
+ */
+LIST_HEAD(hsi_board_list);
+EXPORT_SYMBOL_GPL(hsi_board_list);
+
+/**
+ * hsi_register_board_info - Register HSI clients information
+ * @info: Array of HSI clients on the board
+ * @len: Length of the array
+ *
+ * HSI clients are statically declared and registered on board files.
+ *
+ * HSI clients will be automatically registered to the HSI bus once the
+ * controller and the port where the clients wishes to attach are registered
+ * to it.
+ *
+ * Return -errno on failure, 0 on success.
+ */
+int __init hsi_register_board_info(struct hsi_board_info const *info,
+							unsigned int len)
+{
+	struct hsi_cl_info *cl_info;
+
+	cl_info = kcalloc(len, sizeof(*cl_info), GFP_KERNEL);
+	if (!cl_info)
+		return -ENOMEM;
+
+	for (; len; len--, info++, cl_info++) {
+		cl_info->info = *info;
+		list_add_tail(&cl_info->list, &hsi_board_list);
+	}
+
+	return 0;
+}
diff --git a/drivers/hsi/hsi_core.c b/drivers/hsi/hsi_core.c
new file mode 100644
index 000000000..a330f58d4
--- /dev/null
+++ b/drivers/hsi/hsi_core.c
@@ -0,0 +1,767 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HSI core.
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ *
+ * Contact: Carlos Chinea <carlos.chinea@nokia.com>
+ */
+#include <linux/hsi/hsi.h>
+#include <linux/compiler.h>
+#include <linux/list.h>
+#include <linux/kobject.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/notifier.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include "hsi_core.h"
+
+static ssize_t modalias_show(struct device *dev,
+			struct device_attribute *a __maybe_unused, char *buf)
+{
+	return sprintf(buf, "hsi:%s\n", dev_name(dev));
+}
+static DEVICE_ATTR_RO(modalias);
+
+static struct attribute *hsi_bus_dev_attrs[] = {
+	&dev_attr_modalias.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(hsi_bus_dev);
+
+static int hsi_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	add_uevent_var(env, "MODALIAS=hsi:%s", dev_name(dev));
+
+	return 0;
+}
+
+static int hsi_bus_match(struct device *dev, struct device_driver *driver)
+{
+	if (of_driver_match_device(dev, driver))
+		return true;
+
+	if (strcmp(dev_name(dev), driver->name) == 0)
+		return true;
+
+	return false;
+}
+
+static struct bus_type hsi_bus_type = {
+	.name		= "hsi",
+	.dev_groups	= hsi_bus_dev_groups,
+	.match		= hsi_bus_match,
+	.uevent		= hsi_bus_uevent,
+};
+
+static void hsi_client_release(struct device *dev)
+{
+	struct hsi_client *cl = to_hsi_client(dev);
+
+	kfree(cl->tx_cfg.channels);
+	kfree(cl->rx_cfg.channels);
+	kfree(cl);
+}
+
+struct hsi_client *hsi_new_client(struct hsi_port *port,
+						struct hsi_board_info *info)
+{
+	struct hsi_client *cl;
+	size_t size;
+
+	cl = kzalloc(sizeof(*cl), GFP_KERNEL);
+	if (!cl)
+		goto err;
+
+	cl->tx_cfg = info->tx_cfg;
+	if (cl->tx_cfg.channels) {
+		size = cl->tx_cfg.num_channels * sizeof(*cl->tx_cfg.channels);
+		cl->tx_cfg.channels = kmemdup(info->tx_cfg.channels, size,
+					      GFP_KERNEL);
+		if (!cl->tx_cfg.channels)
+			goto err_tx;
+	}
+
+	cl->rx_cfg = info->rx_cfg;
+	if (cl->rx_cfg.channels) {
+		size = cl->rx_cfg.num_channels * sizeof(*cl->rx_cfg.channels);
+		cl->rx_cfg.channels = kmemdup(info->rx_cfg.channels, size,
+					      GFP_KERNEL);
+		if (!cl->rx_cfg.channels)
+			goto err_rx;
+	}
+
+	cl->device.bus = &hsi_bus_type;
+	cl->device.parent = &port->device;
+	cl->device.release = hsi_client_release;
+	dev_set_name(&cl->device, "%s", info->name);
+	cl->device.platform_data = info->platform_data;
+	if (info->archdata)
+		cl->device.archdata = *info->archdata;
+	if (device_register(&cl->device) < 0) {
+		pr_err("hsi: failed to register client: %s\n", info->name);
+		put_device(&cl->device);
+		goto err;
+	}
+
+	return cl;
+err_rx:
+	kfree(cl->tx_cfg.channels);
+err_tx:
+	kfree(cl);
+err:
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(hsi_new_client);
+
+static void hsi_scan_board_info(struct hsi_controller *hsi)
+{
+	struct hsi_cl_info *cl_info;
+	struct hsi_port	*p;
+
+	list_for_each_entry(cl_info, &hsi_board_list, list)
+		if (cl_info->info.hsi_id == hsi->id) {
+			p = hsi_find_port_num(hsi, cl_info->info.port);
+			if (!p)
+				continue;
+			hsi_new_client(p, &cl_info->info);
+		}
+}
+
+#ifdef CONFIG_OF
+static struct hsi_board_info hsi_char_dev_info = {
+	.name = "hsi_char",
+};
+
+static int hsi_of_property_parse_mode(struct device_node *client, char *name,
+				      unsigned int *result)
+{
+	const char *mode;
+	int err;
+
+	err = of_property_read_string(client, name, &mode);
+	if (err < 0)
+		return err;
+
+	if (strcmp(mode, "stream") == 0)
+		*result = HSI_MODE_STREAM;
+	else if (strcmp(mode, "frame") == 0)
+		*result = HSI_MODE_FRAME;
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+static int hsi_of_property_parse_flow(struct device_node *client, char *name,
+				      unsigned int *result)
+{
+	const char *flow;
+	int err;
+
+	err = of_property_read_string(client, name, &flow);
+	if (err < 0)
+		return err;
+
+	if (strcmp(flow, "synchronized") == 0)
+		*result = HSI_FLOW_SYNC;
+	else if (strcmp(flow, "pipeline") == 0)
+		*result = HSI_FLOW_PIPE;
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+static int hsi_of_property_parse_arb_mode(struct device_node *client,
+					  char *name, unsigned int *result)
+{
+	const char *arb_mode;
+	int err;
+
+	err = of_property_read_string(client, name, &arb_mode);
+	if (err < 0)
+		return err;
+
+	if (strcmp(arb_mode, "round-robin") == 0)
+		*result = HSI_ARB_RR;
+	else if (strcmp(arb_mode, "priority") == 0)
+		*result = HSI_ARB_PRIO;
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+static void hsi_add_client_from_dt(struct hsi_port *port,
+						struct device_node *client)
+{
+	struct hsi_client *cl;
+	struct hsi_channel channel;
+	struct property *prop;
+	char name[32];
+	int length, cells, err, i, max_chan, mode;
+
+	cl = kzalloc(sizeof(*cl), GFP_KERNEL);
+	if (!cl)
+		return;
+
+	err = of_modalias_node(client, name, sizeof(name));
+	if (err)
+		goto err;
+
+	err = hsi_of_property_parse_mode(client, "hsi-mode", &mode);
+	if (err) {
+		err = hsi_of_property_parse_mode(client, "hsi-rx-mode",
+						 &cl->rx_cfg.mode);
+		if (err)
+			goto err;
+
+		err = hsi_of_property_parse_mode(client, "hsi-tx-mode",
+						 &cl->tx_cfg.mode);
+		if (err)
+			goto err;
+	} else {
+		cl->rx_cfg.mode = mode;
+		cl->tx_cfg.mode = mode;
+	}
+
+	err = of_property_read_u32(client, "hsi-speed-kbps",
+				   &cl->tx_cfg.speed);
+	if (err)
+		goto err;
+	cl->rx_cfg.speed = cl->tx_cfg.speed;
+
+	err = hsi_of_property_parse_flow(client, "hsi-flow",
+					 &cl->rx_cfg.flow);
+	if (err)
+		goto err;
+
+	err = hsi_of_property_parse_arb_mode(client, "hsi-arb-mode",
+					     &cl->rx_cfg.arb_mode);
+	if (err)
+		goto err;
+
+	prop = of_find_property(client, "hsi-channel-ids", &length);
+	if (!prop) {
+		err = -EINVAL;
+		goto err;
+	}
+
+	cells = length / sizeof(u32);
+
+	cl->rx_cfg.num_channels = cells;
+	cl->tx_cfg.num_channels = cells;
+	cl->rx_cfg.channels = kcalloc(cells, sizeof(channel), GFP_KERNEL);
+	if (!cl->rx_cfg.channels) {
+		err = -ENOMEM;
+		goto err;
+	}
+
+	cl->tx_cfg.channels = kcalloc(cells, sizeof(channel), GFP_KERNEL);
+	if (!cl->tx_cfg.channels) {
+		err = -ENOMEM;
+		goto err2;
+	}
+
+	max_chan = 0;
+	for (i = 0; i < cells; i++) {
+		err = of_property_read_u32_index(client, "hsi-channel-ids", i,
+						 &channel.id);
+		if (err)
+			goto err3;
+
+		err = of_property_read_string_index(client, "hsi-channel-names",
+						    i, &channel.name);
+		if (err)
+			channel.name = NULL;
+
+		if (channel.id > max_chan)
+			max_chan = channel.id;
+
+		cl->rx_cfg.channels[i] = channel;
+		cl->tx_cfg.channels[i] = channel;
+	}
+
+	cl->rx_cfg.num_hw_channels = max_chan + 1;
+	cl->tx_cfg.num_hw_channels = max_chan + 1;
+
+	cl->device.bus = &hsi_bus_type;
+	cl->device.parent = &port->device;
+	cl->device.release = hsi_client_release;
+	cl->device.of_node = client;
+
+	dev_set_name(&cl->device, "%s", name);
+	if (device_register(&cl->device) < 0) {
+		pr_err("hsi: failed to register client: %s\n", name);
+		put_device(&cl->device);
+	}
+
+	return;
+
+err3:
+	kfree(cl->tx_cfg.channels);
+err2:
+	kfree(cl->rx_cfg.channels);
+err:
+	kfree(cl);
+	pr_err("hsi client: missing or incorrect of property: err=%d\n", err);
+}
+
+void hsi_add_clients_from_dt(struct hsi_port *port, struct device_node *clients)
+{
+	struct device_node *child;
+
+	/* register hsi-char device */
+	hsi_new_client(port, &hsi_char_dev_info);
+
+	for_each_available_child_of_node(clients, child)
+		hsi_add_client_from_dt(port, child);
+}
+EXPORT_SYMBOL_GPL(hsi_add_clients_from_dt);
+#endif
+
+int hsi_remove_client(struct device *dev, void *data __maybe_unused)
+{
+	device_unregister(dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hsi_remove_client);
+
+static int hsi_remove_port(struct device *dev, void *data __maybe_unused)
+{
+	device_for_each_child(dev, NULL, hsi_remove_client);
+	device_unregister(dev);
+
+	return 0;
+}
+
+static void hsi_controller_release(struct device *dev)
+{
+	struct hsi_controller *hsi = to_hsi_controller(dev);
+
+	kfree(hsi->port);
+	kfree(hsi);
+}
+
+static void hsi_port_release(struct device *dev)
+{
+	kfree(to_hsi_port(dev));
+}
+
+/**
+ * hsi_unregister_port - Unregister an HSI port
+ * @port: The HSI port to unregister
+ */
+void hsi_port_unregister_clients(struct hsi_port *port)
+{
+	device_for_each_child(&port->device, NULL, hsi_remove_client);
+}
+EXPORT_SYMBOL_GPL(hsi_port_unregister_clients);
+
+/**
+ * hsi_unregister_controller - Unregister an HSI controller
+ * @hsi: The HSI controller to register
+ */
+void hsi_unregister_controller(struct hsi_controller *hsi)
+{
+	device_for_each_child(&hsi->device, NULL, hsi_remove_port);
+	device_unregister(&hsi->device);
+}
+EXPORT_SYMBOL_GPL(hsi_unregister_controller);
+
+/**
+ * hsi_register_controller - Register an HSI controller and its ports
+ * @hsi: The HSI controller to register
+ *
+ * Returns -errno on failure, 0 on success.
+ */
+int hsi_register_controller(struct hsi_controller *hsi)
+{
+	unsigned int i;
+	int err;
+
+	err = device_add(&hsi->device);
+	if (err < 0)
+		return err;
+	for (i = 0; i < hsi->num_ports; i++) {
+		hsi->port[i]->device.parent = &hsi->device;
+		err = device_add(&hsi->port[i]->device);
+		if (err < 0)
+			goto out;
+	}
+	/* Populate HSI bus with HSI clients */
+	hsi_scan_board_info(hsi);
+
+	return 0;
+out:
+	while (i-- > 0)
+		device_del(&hsi->port[i]->device);
+	device_del(&hsi->device);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(hsi_register_controller);
+
+/**
+ * hsi_register_client_driver - Register an HSI client to the HSI bus
+ * @drv: HSI client driver to register
+ *
+ * Returns -errno on failure, 0 on success.
+ */
+int hsi_register_client_driver(struct hsi_client_driver *drv)
+{
+	drv->driver.bus = &hsi_bus_type;
+
+	return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(hsi_register_client_driver);
+
+static inline int hsi_dummy_msg(struct hsi_msg *msg __maybe_unused)
+{
+	return 0;
+}
+
+static inline int hsi_dummy_cl(struct hsi_client *cl __maybe_unused)
+{
+	return 0;
+}
+
+/**
+ * hsi_put_controller - Free an HSI controller
+ *
+ * @hsi: Pointer to the HSI controller to freed
+ *
+ * HSI controller drivers should only use this function if they need
+ * to free their allocated hsi_controller structures before a successful
+ * call to hsi_register_controller. Other use is not allowed.
+ */
+void hsi_put_controller(struct hsi_controller *hsi)
+{
+	unsigned int i;
+
+	if (!hsi)
+		return;
+
+	for (i = 0; i < hsi->num_ports; i++)
+		if (hsi->port && hsi->port[i])
+			put_device(&hsi->port[i]->device);
+	put_device(&hsi->device);
+}
+EXPORT_SYMBOL_GPL(hsi_put_controller);
+
+/**
+ * hsi_alloc_controller - Allocate an HSI controller and its ports
+ * @n_ports: Number of ports on the HSI controller
+ * @flags: Kernel allocation flags
+ *
+ * Return NULL on failure or a pointer to an hsi_controller on success.
+ */
+struct hsi_controller *hsi_alloc_controller(unsigned int n_ports, gfp_t flags)
+{
+	struct hsi_controller	*hsi;
+	struct hsi_port		**port;
+	unsigned int		i;
+
+	if (!n_ports)
+		return NULL;
+
+	hsi = kzalloc(sizeof(*hsi), flags);
+	if (!hsi)
+		return NULL;
+	port = kcalloc(n_ports, sizeof(*port), flags);
+	if (!port) {
+		kfree(hsi);
+		return NULL;
+	}
+	hsi->num_ports = n_ports;
+	hsi->port = port;
+	hsi->device.release = hsi_controller_release;
+	device_initialize(&hsi->device);
+
+	for (i = 0; i < n_ports; i++) {
+		port[i] = kzalloc(sizeof(**port), flags);
+		if (port[i] == NULL)
+			goto out;
+		port[i]->num = i;
+		port[i]->async = hsi_dummy_msg;
+		port[i]->setup = hsi_dummy_cl;
+		port[i]->flush = hsi_dummy_cl;
+		port[i]->start_tx = hsi_dummy_cl;
+		port[i]->stop_tx = hsi_dummy_cl;
+		port[i]->release = hsi_dummy_cl;
+		mutex_init(&port[i]->lock);
+		BLOCKING_INIT_NOTIFIER_HEAD(&port[i]->n_head);
+		dev_set_name(&port[i]->device, "port%d", i);
+		hsi->port[i]->device.release = hsi_port_release;
+		device_initialize(&hsi->port[i]->device);
+	}
+
+	return hsi;
+out:
+	hsi_put_controller(hsi);
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(hsi_alloc_controller);
+
+/**
+ * hsi_free_msg - Free an HSI message
+ * @msg: Pointer to the HSI message
+ *
+ * Client is responsible to free the buffers pointed by the scatterlists.
+ */
+void hsi_free_msg(struct hsi_msg *msg)
+{
+	if (!msg)
+		return;
+	sg_free_table(&msg->sgt);
+	kfree(msg);
+}
+EXPORT_SYMBOL_GPL(hsi_free_msg);
+
+/**
+ * hsi_alloc_msg - Allocate an HSI message
+ * @nents: Number of memory entries
+ * @flags: Kernel allocation flags
+ *
+ * nents can be 0. This mainly makes sense for read transfer.
+ * In that case, HSI drivers will call the complete callback when
+ * there is data to be read without consuming it.
+ *
+ * Return NULL on failure or a pointer to an hsi_msg on success.
+ */
+struct hsi_msg *hsi_alloc_msg(unsigned int nents, gfp_t flags)
+{
+	struct hsi_msg *msg;
+	int err;
+
+	msg = kzalloc(sizeof(*msg), flags);
+	if (!msg)
+		return NULL;
+
+	if (!nents)
+		return msg;
+
+	err = sg_alloc_table(&msg->sgt, nents, flags);
+	if (unlikely(err)) {
+		kfree(msg);
+		msg = NULL;
+	}
+
+	return msg;
+}
+EXPORT_SYMBOL_GPL(hsi_alloc_msg);
+
+/**
+ * hsi_async - Submit an HSI transfer to the controller
+ * @cl: HSI client sending the transfer
+ * @msg: The HSI transfer passed to controller
+ *
+ * The HSI message must have the channel, ttype, complete and destructor
+ * fields set beforehand. If nents > 0 then the client has to initialize
+ * also the scatterlists to point to the buffers to write to or read from.
+ *
+ * HSI controllers relay on pre-allocated buffers from their clients and they
+ * do not allocate buffers on their own.
+ *
+ * Once the HSI message transfer finishes, the HSI controller calls the
+ * complete callback with the status and actual_len fields of the HSI message
+ * updated. The complete callback can be called before returning from
+ * hsi_async.
+ *
+ * Returns -errno on failure or 0 on success
+ */
+int hsi_async(struct hsi_client *cl, struct hsi_msg *msg)
+{
+	struct hsi_port *port = hsi_get_port(cl);
+
+	if (!hsi_port_claimed(cl))
+		return -EACCES;
+
+	WARN_ON_ONCE(!msg->destructor || !msg->complete);
+	msg->cl = cl;
+
+	return port->async(msg);
+}
+EXPORT_SYMBOL_GPL(hsi_async);
+
+/**
+ * hsi_claim_port - Claim the HSI client's port
+ * @cl: HSI client that wants to claim its port
+ * @share: Flag to indicate if the client wants to share the port or not.
+ *
+ * Returns -errno on failure, 0 on success.
+ */
+int hsi_claim_port(struct hsi_client *cl, unsigned int share)
+{
+	struct hsi_port *port = hsi_get_port(cl);
+	int err = 0;
+
+	mutex_lock(&port->lock);
+	if ((port->claimed) && (!port->shared || !share)) {
+		err = -EBUSY;
+		goto out;
+	}
+	if (!try_module_get(to_hsi_controller(port->device.parent)->owner)) {
+		err = -ENODEV;
+		goto out;
+	}
+	port->claimed++;
+	port->shared = !!share;
+	cl->pclaimed = 1;
+out:
+	mutex_unlock(&port->lock);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(hsi_claim_port);
+
+/**
+ * hsi_release_port - Release the HSI client's port
+ * @cl: HSI client which previously claimed its port
+ */
+void hsi_release_port(struct hsi_client *cl)
+{
+	struct hsi_port *port = hsi_get_port(cl);
+
+	mutex_lock(&port->lock);
+	/* Allow HW driver to do some cleanup */
+	port->release(cl);
+	if (cl->pclaimed)
+		port->claimed--;
+	BUG_ON(port->claimed < 0);
+	cl->pclaimed = 0;
+	if (!port->claimed)
+		port->shared = 0;
+	module_put(to_hsi_controller(port->device.parent)->owner);
+	mutex_unlock(&port->lock);
+}
+EXPORT_SYMBOL_GPL(hsi_release_port);
+
+static int hsi_event_notifier_call(struct notifier_block *nb,
+				unsigned long event, void *data __maybe_unused)
+{
+	struct hsi_client *cl = container_of(nb, struct hsi_client, nb);
+
+	(*cl->ehandler)(cl, event);
+
+	return 0;
+}
+
+/**
+ * hsi_register_port_event - Register a client to receive port events
+ * @cl: HSI client that wants to receive port events
+ * @handler: Event handler callback
+ *
+ * Clients should register a callback to be able to receive
+ * events from the ports. Registration should happen after
+ * claiming the port.
+ * The handler can be called in interrupt context.
+ *
+ * Returns -errno on error, or 0 on success.
+ */
+int hsi_register_port_event(struct hsi_client *cl,
+			void (*handler)(struct hsi_client *, unsigned long))
+{
+	struct hsi_port *port = hsi_get_port(cl);
+
+	if (!handler || cl->ehandler)
+		return -EINVAL;
+	if (!hsi_port_claimed(cl))
+		return -EACCES;
+	cl->ehandler = handler;
+	cl->nb.notifier_call = hsi_event_notifier_call;
+
+	return blocking_notifier_chain_register(&port->n_head, &cl->nb);
+}
+EXPORT_SYMBOL_GPL(hsi_register_port_event);
+
+/**
+ * hsi_unregister_port_event - Stop receiving port events for a client
+ * @cl: HSI client that wants to stop receiving port events
+ *
+ * Clients should call this function before releasing their associated
+ * port.
+ *
+ * Returns -errno on error, or 0 on success.
+ */
+int hsi_unregister_port_event(struct hsi_client *cl)
+{
+	struct hsi_port *port = hsi_get_port(cl);
+	int err;
+
+	WARN_ON(!hsi_port_claimed(cl));
+
+	err = blocking_notifier_chain_unregister(&port->n_head, &cl->nb);
+	if (!err)
+		cl->ehandler = NULL;
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(hsi_unregister_port_event);
+
+/**
+ * hsi_event - Notifies clients about port events
+ * @port: Port where the event occurred
+ * @event: The event type
+ *
+ * Clients should not be concerned about wake line behavior. However, due
+ * to a race condition in HSI HW protocol, clients need to be notified
+ * about wake line changes, so they can implement a workaround for it.
+ *
+ * Events:
+ * HSI_EVENT_START_RX - Incoming wake line high
+ * HSI_EVENT_STOP_RX - Incoming wake line down
+ *
+ * Returns -errno on error, or 0 on success.
+ */
+int hsi_event(struct hsi_port *port, unsigned long event)
+{
+	return blocking_notifier_call_chain(&port->n_head, event, NULL);
+}
+EXPORT_SYMBOL_GPL(hsi_event);
+
+/**
+ * hsi_get_channel_id_by_name - acquire channel id by channel name
+ * @cl: HSI client, which uses the channel
+ * @name: name the channel is known under
+ *
+ * Clients can call this function to get the hsi channel ids similar to
+ * requesting IRQs or GPIOs by name. This function assumes the same
+ * channel configuration is used for RX and TX.
+ *
+ * Returns -errno on error or channel id on success.
+ */
+int hsi_get_channel_id_by_name(struct hsi_client *cl, char *name)
+{
+	int i;
+
+	if (!cl->rx_cfg.channels)
+		return -ENOENT;
+
+	for (i = 0; i < cl->rx_cfg.num_channels; i++)
+		if (!strcmp(cl->rx_cfg.channels[i].name, name))
+			return cl->rx_cfg.channels[i].id;
+
+	return -ENXIO;
+}
+EXPORT_SYMBOL_GPL(hsi_get_channel_id_by_name);
+
+static int __init hsi_init(void)
+{
+	return bus_register(&hsi_bus_type);
+}
+postcore_initcall(hsi_init);
+
+static void __exit hsi_exit(void)
+{
+	bus_unregister(&hsi_bus_type);
+}
+module_exit(hsi_exit);
+
+MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
+MODULE_DESCRIPTION("High-speed Synchronous Serial Interface (HSI) framework");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/hsi/hsi_core.h b/drivers/hsi/hsi_core.h
new file mode 100644
index 000000000..bdb06ca09
--- /dev/null
+++ b/drivers/hsi/hsi_core.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * HSI framework internal interfaces,
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ *
+ * Contact: Carlos Chinea <carlos.chinea@nokia.com>
+ */
+
+#ifndef __LINUX_HSI_CORE_H__
+#define __LINUX_HSI_CORE_H__
+
+#include <linux/hsi/hsi.h>
+
+struct hsi_cl_info {
+	struct list_head	list;
+	struct hsi_board_info	info;
+};
+
+extern struct list_head hsi_board_list;
+
+#endif /* __LINUX_HSI_CORE_H__ */