Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

5 files changed, 1957 insertions, 0 deletions

diff --git a/drivers/misc/ti-st/Kconfig b/drivers/misc/ti-st/Kconfig
new file mode 100644
index 000000000..1503a6496
--- /dev/null
+++ b/drivers/misc/ti-st/Kconfig
@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# TI's shared transport line discipline and the protocol
+# drivers (BT, FM and GPS)
+#
+menu "Texas Instruments shared transport line discipline"
+config TI_ST
+	tristate "Shared transport core driver"
+	depends on NET && TTY
+	depends on GPIOLIB || COMPILE_TEST
+	select FW_LOADER
+	help
+	  This enables the shared transport core driver for TI
+	  BT / FM and GPS combo chips. This enables protocol drivers
+	  to register themselves with core and send data, the responses
+	  are returned to relevant protocol drivers based on their
+	  packet types.
+
+endmenu
diff --git a/drivers/misc/ti-st/Makefile b/drivers/misc/ti-st/Makefile
new file mode 100644
index 000000000..933931009
--- /dev/null
+++ b/drivers/misc/ti-st/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for TI's shared transport line discipline
+# and its protocol drivers (BT, FM, GPS)
+#
+obj-$(CONFIG_TI_ST) 		+= st_drv.o
+st_drv-objs			:= st_core.o st_kim.o st_ll.o
diff --git a/drivers/misc/ti-st/st_core.c b/drivers/misc/ti-st/st_core.c
new file mode 100644
index 000000000..ca115f344
--- /dev/null
+++ b/drivers/misc/ti-st/st_core.c
@@ -0,0 +1,929 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Shared Transport Line discipline driver Core
+ *	This hooks up ST KIM driver and ST LL driver
+ *  Copyright (C) 2009-2010 Texas Instruments
+ *  Author: Pavan Savoy <pavan_savoy@ti.com>
+ */
+
+#define pr_fmt(fmt)	"(stc): " fmt
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/tty.h>
+
+#include <linux/seq_file.h>
+#include <linux/skbuff.h>
+
+#include <linux/ti_wilink_st.h>
+#include <linux/netdevice.h>
+
+extern void st_kim_recv(void *, const unsigned char *, long);
+void st_int_recv(void *, const unsigned char *, long);
+/*
+ * function pointer pointing to either,
+ * st_kim_recv during registration to receive fw download responses
+ * st_int_recv after registration to receive proto stack responses
+ */
+static void (*st_recv) (void *, const unsigned char *, long);
+
+/********************************************************************/
+static void add_channel_to_table(struct st_data_s *st_gdata,
+		struct st_proto_s *new_proto)
+{
+	pr_info("%s: id %d\n", __func__, new_proto->chnl_id);
+	/* list now has the channel id as index itself */
+	st_gdata->list[new_proto->chnl_id] = new_proto;
+	st_gdata->is_registered[new_proto->chnl_id] = true;
+}
+
+static void remove_channel_from_table(struct st_data_s *st_gdata,
+		struct st_proto_s *proto)
+{
+	pr_info("%s: id %d\n", __func__, proto->chnl_id);
+/*	st_gdata->list[proto->chnl_id] = NULL; */
+	st_gdata->is_registered[proto->chnl_id] = false;
+}
+
+/*
+ * called from KIM during firmware download.
+ *
+ * This is a wrapper function to tty->ops->write_room.
+ * It returns number of free space available in
+ * uart tx buffer.
+ */
+int st_get_uart_wr_room(struct st_data_s *st_gdata)
+{
+	struct tty_struct *tty;
+	if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
+		pr_err("tty unavailable to perform write");
+		return -1;
+	}
+	tty = st_gdata->tty;
+	return tty->ops->write_room(tty);
+}
+
+/*
+ * can be called in from
+ * -- KIM (during fw download)
+ * -- ST Core (during st_write)
+ *
+ *  This is the internal write function - a wrapper
+ *  to tty->ops->write
+ */
+int st_int_write(struct st_data_s *st_gdata,
+	const unsigned char *data, int count)
+{
+	struct tty_struct *tty;
+	if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
+		pr_err("tty unavailable to perform write");
+		return -EINVAL;
+	}
+	tty = st_gdata->tty;
+#ifdef VERBOSE
+	print_hex_dump(KERN_DEBUG, "<out<", DUMP_PREFIX_NONE,
+		16, 1, data, count, 0);
+#endif
+	return tty->ops->write(tty, data, count);
+
+}
+
+/*
+ * push the skb received to relevant
+ * protocol stacks
+ */
+static void st_send_frame(unsigned char chnl_id, struct st_data_s *st_gdata)
+{
+	pr_debug(" %s(prot:%d) ", __func__, chnl_id);
+
+	if (unlikely
+	    (st_gdata == NULL || st_gdata->rx_skb == NULL
+	     || st_gdata->is_registered[chnl_id] == false)) {
+		pr_err("chnl_id %d not registered, no data to send?",
+			   chnl_id);
+		kfree_skb(st_gdata->rx_skb);
+		return;
+	}
+	/*
+	 * this cannot fail
+	 * this shouldn't take long
+	 * - should be just skb_queue_tail for the
+	 *   protocol stack driver
+	 */
+	if (likely(st_gdata->list[chnl_id]->recv != NULL)) {
+		if (unlikely
+			(st_gdata->list[chnl_id]->recv
+			(st_gdata->list[chnl_id]->priv_data, st_gdata->rx_skb)
+			     != 0)) {
+			pr_err(" proto stack %d's ->recv failed", chnl_id);
+			kfree_skb(st_gdata->rx_skb);
+			return;
+		}
+	} else {
+		pr_err(" proto stack %d's ->recv null", chnl_id);
+		kfree_skb(st_gdata->rx_skb);
+	}
+	return;
+}
+
+/*
+ * st_reg_complete - to call registration complete callbacks
+ * of all protocol stack drivers
+ * This function is being called with spin lock held, protocol drivers are
+ * only expected to complete their waits and do nothing more than that.
+ */
+static void st_reg_complete(struct st_data_s *st_gdata, int err)
+{
+	unsigned char i = 0;
+	pr_info(" %s ", __func__);
+	for (i = 0; i < ST_MAX_CHANNELS; i++) {
+		if (likely(st_gdata != NULL &&
+			st_gdata->is_registered[i] == true &&
+				st_gdata->list[i]->reg_complete_cb != NULL)) {
+			st_gdata->list[i]->reg_complete_cb
+				(st_gdata->list[i]->priv_data, err);
+			pr_info("protocol %d's cb sent %d\n", i, err);
+			if (err) { /* cleanup registered protocol */
+				st_gdata->is_registered[i] = false;
+				if (st_gdata->protos_registered)
+					st_gdata->protos_registered--;
+			}
+		}
+	}
+}
+
+static inline int st_check_data_len(struct st_data_s *st_gdata,
+	unsigned char chnl_id, int len)
+{
+	int room = skb_tailroom(st_gdata->rx_skb);
+
+	pr_debug("len %d room %d", len, room);
+
+	if (!len) {
+		/*
+		 * Received packet has only packet header and
+		 * has zero length payload. So, ask ST CORE to
+		 * forward the packet to protocol driver (BT/FM/GPS)
+		 */
+		st_send_frame(chnl_id, st_gdata);
+
+	} else if (len > room) {
+		/*
+		 * Received packet's payload length is larger.
+		 * We can't accommodate it in created skb.
+		 */
+		pr_err("Data length is too large len %d room %d", len,
+			   room);
+		kfree_skb(st_gdata->rx_skb);
+	} else {
+		/*
+		 * Packet header has non-zero payload length and
+		 * we have enough space in created skb. Lets read
+		 * payload data */
+		st_gdata->rx_state = ST_W4_DATA;
+		st_gdata->rx_count = len;
+		return len;
+	}
+
+	/* Change ST state to continue to process next packet */
+	st_gdata->rx_state = ST_W4_PACKET_TYPE;
+	st_gdata->rx_skb = NULL;
+	st_gdata->rx_count = 0;
+	st_gdata->rx_chnl = 0;
+
+	return 0;
+}
+
+/*
+ * st_wakeup_ack - internal function for action when wake-up ack
+ *	received
+ */
+static inline void st_wakeup_ack(struct st_data_s *st_gdata,
+	unsigned char cmd)
+{
+	struct sk_buff *waiting_skb;
+	unsigned long flags = 0;
+
+	spin_lock_irqsave(&st_gdata->lock, flags);
+	/*
+	 * de-Q from waitQ and Q in txQ now that the
+	 * chip is awake
+	 */
+	while ((waiting_skb = skb_dequeue(&st_gdata->tx_waitq)))
+		skb_queue_tail(&st_gdata->txq, waiting_skb);
+
+	/* state forwarded to ST LL */
+	st_ll_sleep_state(st_gdata, (unsigned long)cmd);
+	spin_unlock_irqrestore(&st_gdata->lock, flags);
+
+	/* wake up to send the recently copied skbs from waitQ */
+	st_tx_wakeup(st_gdata);
+}
+
+/*
+ * st_int_recv - ST's internal receive function.
+ *	Decodes received RAW data and forwards to corresponding
+ *	client drivers (Bluetooth,FM,GPS..etc).
+ *	This can receive various types of packets,
+ *	HCI-Events, ACL, SCO, 4 types of HCI-LL PM packets
+ *	CH-8 packets from FM, CH-9 packets from GPS cores.
+ */
+void st_int_recv(void *disc_data,
+	const unsigned char *data, long count)
+{
+	char *ptr;
+	struct st_proto_s *proto;
+	unsigned short payload_len = 0;
+	int len = 0;
+	unsigned char type = 0;
+	unsigned char *plen;
+	struct st_data_s *st_gdata = (struct st_data_s *)disc_data;
+	unsigned long flags;
+
+	ptr = (char *)data;
+	/* tty_receive sent null ? */
+	if (unlikely(ptr == NULL) || (st_gdata == NULL)) {
+		pr_err(" received null from TTY ");
+		return;
+	}
+
+	pr_debug("count %ld rx_state %ld"
+		   "rx_count %ld", count, st_gdata->rx_state,
+		   st_gdata->rx_count);
+
+	spin_lock_irqsave(&st_gdata->lock, flags);
+	/* Decode received bytes here */
+	while (count) {
+		if (st_gdata->rx_count) {
+			len = min_t(unsigned int, st_gdata->rx_count, count);
+			skb_put_data(st_gdata->rx_skb, ptr, len);
+			st_gdata->rx_count -= len;
+			count -= len;
+			ptr += len;
+
+			if (st_gdata->rx_count)
+				continue;
+
+			/* Check ST RX state machine , where are we? */
+			switch (st_gdata->rx_state) {
+			/* Waiting for complete packet ? */
+			case ST_W4_DATA:
+				pr_debug("Complete pkt received");
+				/*
+				 * Ask ST CORE to forward
+				 * the packet to protocol driver
+				 */
+				st_send_frame(st_gdata->rx_chnl, st_gdata);
+
+				st_gdata->rx_state = ST_W4_PACKET_TYPE;
+				st_gdata->rx_skb = NULL;
+				continue;
+			/* parse the header to know details */
+			case ST_W4_HEADER:
+				proto = st_gdata->list[st_gdata->rx_chnl];
+				plen =
+				&st_gdata->rx_skb->data
+				[proto->offset_len_in_hdr];
+				pr_debug("plen pointing to %x\n", *plen);
+				if (proto->len_size == 1) /* 1 byte len field */
+					payload_len = *(unsigned char *)plen;
+				else if (proto->len_size == 2)
+					payload_len =
+					__le16_to_cpu(*(unsigned short *)plen);
+				else
+					pr_info("%s: invalid length "
+					"for id %d\n",
+					__func__, proto->chnl_id);
+				st_check_data_len(st_gdata, proto->chnl_id,
+						payload_len);
+				pr_debug("off %d, pay len %d\n",
+					proto->offset_len_in_hdr, payload_len);
+				continue;
+			}	/* end of switch rx_state */
+		}
+
+		/* end of if rx_count */
+
+		/*
+		 * Check first byte of packet and identify module
+		 * owner (BT/FM/GPS)
+		 */
+		switch (*ptr) {
+		case LL_SLEEP_IND:
+		case LL_SLEEP_ACK:
+		case LL_WAKE_UP_IND:
+			pr_debug("PM packet");
+			/*
+			 * this takes appropriate action based on
+			 * sleep state received --
+			 */
+			st_ll_sleep_state(st_gdata, *ptr);
+			/*
+			 * if WAKEUP_IND collides copy from waitq to txq
+			 * and assume chip awake
+			 */
+			spin_unlock_irqrestore(&st_gdata->lock, flags);
+			if (st_ll_getstate(st_gdata) == ST_LL_AWAKE)
+				st_wakeup_ack(st_gdata, LL_WAKE_UP_ACK);
+			spin_lock_irqsave(&st_gdata->lock, flags);
+
+			ptr++;
+			count--;
+			continue;
+		case LL_WAKE_UP_ACK:
+			pr_debug("PM packet");
+
+			spin_unlock_irqrestore(&st_gdata->lock, flags);
+			/* wake up ack received */
+			st_wakeup_ack(st_gdata, *ptr);
+			spin_lock_irqsave(&st_gdata->lock, flags);
+
+			ptr++;
+			count--;
+			continue;
+			/* Unknow packet? */
+		default:
+			type = *ptr;
+
+			/*
+			 * Default case means non-HCILL packets,
+			 * possibilities are packets for:
+			 * (a) valid protocol -  Supported Protocols within
+			 *     the ST_MAX_CHANNELS.
+			 * (b) registered protocol - Checked by
+			 *     "st_gdata->list[type] == NULL)" are supported
+			 *     protocols only.
+			 *  Rules out any invalid protocol and
+			 *  unregistered protocols with channel ID < 16.
+			 */
+
+			if ((type >= ST_MAX_CHANNELS) ||
+					(st_gdata->list[type] == NULL)) {
+				pr_err("chip/interface misbehavior: "
+						"dropping frame starting "
+						"with 0x%02x\n", type);
+				goto done;
+			}
+
+			st_gdata->rx_skb = alloc_skb(
+					st_gdata->list[type]->max_frame_size,
+					GFP_ATOMIC);
+			if (st_gdata->rx_skb == NULL) {
+				pr_err("out of memory: dropping\n");
+				goto done;
+			}
+
+			skb_reserve(st_gdata->rx_skb,
+					st_gdata->list[type]->reserve);
+			/* next 2 required for BT only */
+			st_gdata->rx_skb->cb[0] = type; /*pkt_type*/
+			st_gdata->rx_skb->cb[1] = 0; /*incoming*/
+			st_gdata->rx_chnl = *ptr;
+			st_gdata->rx_state = ST_W4_HEADER;
+			st_gdata->rx_count = st_gdata->list[type]->hdr_len;
+			pr_debug("rx_count %ld\n", st_gdata->rx_count);
+		};
+		ptr++;
+		count--;
+	}
+done:
+	spin_unlock_irqrestore(&st_gdata->lock, flags);
+	pr_debug("done %s", __func__);
+	return;
+}
+
+/*
+ * st_int_dequeue - internal de-Q function.
+ *	If the previous data set was not written
+ *	completely, return that skb which has the pending data.
+ *	In normal cases, return top of txq.
+ */
+static struct sk_buff *st_int_dequeue(struct st_data_s *st_gdata)
+{
+	struct sk_buff *returning_skb;
+
+	pr_debug("%s", __func__);
+	if (st_gdata->tx_skb != NULL) {
+		returning_skb = st_gdata->tx_skb;
+		st_gdata->tx_skb = NULL;
+		return returning_skb;
+	}
+	return skb_dequeue(&st_gdata->txq);
+}
+
+/*
+ * st_int_enqueue - internal Q-ing function.
+ *	Will either Q the skb to txq or the tx_waitq
+ *	depending on the ST LL state.
+ *	If the chip is asleep, then Q it onto waitq and
+ *	wakeup the chip.
+ *	txq and waitq needs protection since the other contexts
+ *	may be sending data, waking up chip.
+ */
+static void st_int_enqueue(struct st_data_s *st_gdata, struct sk_buff *skb)
+{
+	unsigned long flags = 0;
+
+	pr_debug("%s", __func__);
+	spin_lock_irqsave(&st_gdata->lock, flags);
+
+	switch (st_ll_getstate(st_gdata)) {
+	case ST_LL_AWAKE:
+		pr_debug("ST LL is AWAKE, sending normally");
+		skb_queue_tail(&st_gdata->txq, skb);
+		break;
+	case ST_LL_ASLEEP_TO_AWAKE:
+		skb_queue_tail(&st_gdata->tx_waitq, skb);
+		break;
+	case ST_LL_AWAKE_TO_ASLEEP:
+		pr_err("ST LL is illegal state(%ld),"
+			   "purging received skb.", st_ll_getstate(st_gdata));
+		dev_kfree_skb_irq(skb);
+		break;
+	case ST_LL_ASLEEP:
+		skb_queue_tail(&st_gdata->tx_waitq, skb);
+		st_ll_wakeup(st_gdata);
+		break;
+	default:
+		pr_err("ST LL is illegal state(%ld),"
+			   "purging received skb.", st_ll_getstate(st_gdata));
+		dev_kfree_skb_irq(skb);
+		break;
+	}
+
+	spin_unlock_irqrestore(&st_gdata->lock, flags);
+	pr_debug("done %s", __func__);
+	return;
+}
+
+/*
+ * internal wakeup function
+ * called from either
+ * - TTY layer when write's finished
+ * - st_write (in context of the protocol stack)
+ */
+static void work_fn_write_wakeup(struct work_struct *work)
+{
+	struct st_data_s *st_gdata = container_of(work, struct st_data_s,
+			work_write_wakeup);
+
+	st_tx_wakeup((void *)st_gdata);
+}
+void st_tx_wakeup(struct st_data_s *st_data)
+{
+	struct sk_buff *skb;
+	unsigned long flags;	/* for irq save flags */
+	pr_debug("%s", __func__);
+	/* check for sending & set flag sending here */
+	if (test_and_set_bit(ST_TX_SENDING, &st_data->tx_state)) {
+		pr_debug("ST already sending");
+		/* keep sending */
+		set_bit(ST_TX_WAKEUP, &st_data->tx_state);
+		return;
+		/* TX_WAKEUP will be checked in another
+		 * context
+		 */
+	}
+	do {			/* come back if st_tx_wakeup is set */
+		/* woke-up to write */
+		clear_bit(ST_TX_WAKEUP, &st_data->tx_state);
+		while ((skb = st_int_dequeue(st_data))) {
+			int len;
+			spin_lock_irqsave(&st_data->lock, flags);
+			/* enable wake-up from TTY */
+			set_bit(TTY_DO_WRITE_WAKEUP, &st_data->tty->flags);
+			len = st_int_write(st_data, skb->data, skb->len);
+			skb_pull(skb, len);
+			/* if skb->len = len as expected, skb->len=0 */
+			if (skb->len) {
+				/* would be the next skb to be sent */
+				st_data->tx_skb = skb;
+				spin_unlock_irqrestore(&st_data->lock, flags);
+				break;
+			}
+			dev_kfree_skb_irq(skb);
+			spin_unlock_irqrestore(&st_data->lock, flags);
+		}
+		/* if wake-up is set in another context- restart sending */
+	} while (test_bit(ST_TX_WAKEUP, &st_data->tx_state));
+
+	/* clear flag sending */
+	clear_bit(ST_TX_SENDING, &st_data->tx_state);
+}
+
+/********************************************************************/
+/* functions called from ST KIM
+*/
+void kim_st_list_protocols(struct st_data_s *st_gdata, void *buf)
+{
+	seq_printf(buf, "[%d]\nBT=%c\nFM=%c\nGPS=%c\n",
+			st_gdata->protos_registered,
+			st_gdata->is_registered[0x04] == true ? 'R' : 'U',
+			st_gdata->is_registered[0x08] == true ? 'R' : 'U',
+			st_gdata->is_registered[0x09] == true ? 'R' : 'U');
+}
+
+/********************************************************************/
+/*
+ * functions called from protocol stack drivers
+ * to be EXPORT-ed
+ */
+long st_register(struct st_proto_s *new_proto)
+{
+	struct st_data_s	*st_gdata;
+	long err = 0;
+	unsigned long flags = 0;
+
+	st_kim_ref(&st_gdata, 0);
+	if (st_gdata == NULL || new_proto == NULL || new_proto->recv == NULL
+	    || new_proto->reg_complete_cb == NULL) {
+		pr_err("gdata/new_proto/recv or reg_complete_cb not ready");
+		return -EINVAL;
+	}
+
+	if (new_proto->chnl_id >= ST_MAX_CHANNELS) {
+		pr_err("chnl_id %d not supported", new_proto->chnl_id);
+		return -EPROTONOSUPPORT;
+	}
+
+	if (st_gdata->is_registered[new_proto->chnl_id] == true) {
+		pr_err("chnl_id %d already registered", new_proto->chnl_id);
+		return -EALREADY;
+	}
+
+	/* can be from process context only */
+	spin_lock_irqsave(&st_gdata->lock, flags);
+
+	if (test_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state)) {
+		pr_info(" ST_REG_IN_PROGRESS:%d ", new_proto->chnl_id);
+		/* fw download in progress */
+
+		add_channel_to_table(st_gdata, new_proto);
+		st_gdata->protos_registered++;
+		new_proto->write = st_write;
+
+		set_bit(ST_REG_PENDING, &st_gdata->st_state);
+		spin_unlock_irqrestore(&st_gdata->lock, flags);
+		return -EINPROGRESS;
+	} else if (st_gdata->protos_registered == ST_EMPTY) {
+		pr_info(" chnl_id list empty :%d ", new_proto->chnl_id);
+		set_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
+		st_recv = st_kim_recv;
+
+		/* enable the ST LL - to set default chip state */
+		st_ll_enable(st_gdata);
+
+		/* release lock previously held - re-locked below */
+		spin_unlock_irqrestore(&st_gdata->lock, flags);
+
+		/*
+		 * this may take a while to complete
+		 * since it involves BT fw download
+		 */
+		err = st_kim_start(st_gdata->kim_data);
+		if (err != 0) {
+			clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
+			if ((st_gdata->protos_registered != ST_EMPTY) &&
+			    (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
+				pr_err(" KIM failure complete callback ");
+				spin_lock_irqsave(&st_gdata->lock, flags);
+				st_reg_complete(st_gdata, err);
+				spin_unlock_irqrestore(&st_gdata->lock, flags);
+				clear_bit(ST_REG_PENDING, &st_gdata->st_state);
+			}
+			return -EINVAL;
+		}
+
+		spin_lock_irqsave(&st_gdata->lock, flags);
+
+		clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
+		st_recv = st_int_recv;
+
+		/*
+		 * this is where all pending registration
+		 * are signalled to be complete by calling callback functions
+		 */
+		if ((st_gdata->protos_registered != ST_EMPTY) &&
+		    (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
+			pr_debug(" call reg complete callback ");
+			st_reg_complete(st_gdata, 0);
+		}
+		clear_bit(ST_REG_PENDING, &st_gdata->st_state);
+
+		/*
+		 * check for already registered once more,
+		 * since the above check is old
+		 */
+		if (st_gdata->is_registered[new_proto->chnl_id] == true) {
+			pr_err(" proto %d already registered ",
+				   new_proto->chnl_id);
+			spin_unlock_irqrestore(&st_gdata->lock, flags);
+			return -EALREADY;
+		}
+
+		add_channel_to_table(st_gdata, new_proto);
+		st_gdata->protos_registered++;
+		new_proto->write = st_write;
+		spin_unlock_irqrestore(&st_gdata->lock, flags);
+		return err;
+	}
+	/* if fw is already downloaded & new stack registers protocol */
+	else {
+		add_channel_to_table(st_gdata, new_proto);
+		st_gdata->protos_registered++;
+		new_proto->write = st_write;
+
+		/* lock already held before entering else */
+		spin_unlock_irqrestore(&st_gdata->lock, flags);
+		return err;
+	}
+}
+EXPORT_SYMBOL_GPL(st_register);
+
+/*
+ * to unregister a protocol -
+ * to be called from protocol stack driver
+ */
+long st_unregister(struct st_proto_s *proto)
+{
+	long err = 0;
+	unsigned long flags = 0;
+	struct st_data_s	*st_gdata;
+
+	pr_debug("%s: %d ", __func__, proto->chnl_id);
+
+	st_kim_ref(&st_gdata, 0);
+	if (!st_gdata || proto->chnl_id >= ST_MAX_CHANNELS) {
+		pr_err(" chnl_id %d not supported", proto->chnl_id);
+		return -EPROTONOSUPPORT;
+	}
+
+	spin_lock_irqsave(&st_gdata->lock, flags);
+
+	if (st_gdata->is_registered[proto->chnl_id] == false) {
+		pr_err(" chnl_id %d not registered", proto->chnl_id);
+		spin_unlock_irqrestore(&st_gdata->lock, flags);
+		return -EPROTONOSUPPORT;
+	}
+
+	if (st_gdata->protos_registered)
+		st_gdata->protos_registered--;
+
+	remove_channel_from_table(st_gdata, proto);
+	spin_unlock_irqrestore(&st_gdata->lock, flags);
+
+	if ((st_gdata->protos_registered == ST_EMPTY) &&
+	    (!test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
+		pr_info(" all chnl_ids unregistered ");
+
+		/* stop traffic on tty */
+		if (st_gdata->tty) {
+			tty_ldisc_flush(st_gdata->tty);
+			stop_tty(st_gdata->tty);
+		}
+
+		/* all chnl_ids now unregistered */
+		st_kim_stop(st_gdata->kim_data);
+		/* disable ST LL */
+		st_ll_disable(st_gdata);
+	}
+	return err;
+}
+
+/*
+ * called in protocol stack drivers
+ * via the write function pointer
+ */
+long st_write(struct sk_buff *skb)
+{
+	struct st_data_s *st_gdata;
+	long len;
+
+	st_kim_ref(&st_gdata, 0);
+	if (unlikely(skb == NULL || st_gdata == NULL
+		|| st_gdata->tty == NULL)) {
+		pr_err("data/tty unavailable to perform write");
+		return -EINVAL;
+	}
+
+	pr_debug("%d to be written", skb->len);
+	len = skb->len;
+
+	/* st_ll to decide where to enqueue the skb */
+	st_int_enqueue(st_gdata, skb);
+	/* wake up */
+	st_tx_wakeup(st_gdata);
+
+	/* return number of bytes written */
+	return len;
+}
+
+/* for protocols making use of shared transport */
+EXPORT_SYMBOL_GPL(st_unregister);
+
+/********************************************************************/
+/*
+ * functions called from TTY layer
+ */
+static int st_tty_open(struct tty_struct *tty)
+{
+	struct st_data_s *st_gdata;
+	pr_info("%s ", __func__);
+
+	st_kim_ref(&st_gdata, 0);
+	st_gdata->tty = tty;
+	tty->disc_data = st_gdata;
+
+	/* don't do an wakeup for now */
+	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+
+	/* mem already allocated
+	 */
+	tty->receive_room = 65536;
+	/* Flush any pending characters in the driver and discipline. */
+	tty_ldisc_flush(tty);
+	tty_driver_flush_buffer(tty);
+	/*
+	 * signal to UIM via KIM that -
+	 * installation of N_TI_WL ldisc is complete
+	 */
+	st_kim_complete(st_gdata->kim_data);
+	pr_debug("done %s", __func__);
+
+	return 0;
+}
+
+static void st_tty_close(struct tty_struct *tty)
+{
+	unsigned char i;
+	unsigned long flags;
+	struct	st_data_s *st_gdata = tty->disc_data;
+
+	pr_info("%s ", __func__);
+
+	/*
+	 * TODO:
+	 * if a protocol has been registered & line discipline
+	 * un-installed for some reason - what should be done ?
+	 */
+	spin_lock_irqsave(&st_gdata->lock, flags);
+	for (i = ST_BT; i < ST_MAX_CHANNELS; i++) {
+		if (st_gdata->is_registered[i] == true)
+			pr_err("%d not un-registered", i);
+		st_gdata->list[i] = NULL;
+		st_gdata->is_registered[i] = false;
+	}
+	st_gdata->protos_registered = 0;
+	spin_unlock_irqrestore(&st_gdata->lock, flags);
+	/*
+	 * signal to UIM via KIM that -
+	 * N_TI_WL ldisc is un-installed
+	 */
+	st_kim_complete(st_gdata->kim_data);
+	st_gdata->tty = NULL;
+	/* Flush any pending characters in the driver and discipline. */
+	tty_ldisc_flush(tty);
+	tty_driver_flush_buffer(tty);
+
+	spin_lock_irqsave(&st_gdata->lock, flags);
+	/* empty out txq and tx_waitq */
+	skb_queue_purge(&st_gdata->txq);
+	skb_queue_purge(&st_gdata->tx_waitq);
+	/* reset the TTY Rx states of ST */
+	st_gdata->rx_count = 0;
+	st_gdata->rx_state = ST_W4_PACKET_TYPE;
+	kfree_skb(st_gdata->rx_skb);
+	st_gdata->rx_skb = NULL;
+	spin_unlock_irqrestore(&st_gdata->lock, flags);
+
+	pr_debug("%s: done ", __func__);
+}
+
+static void st_tty_receive(struct tty_struct *tty, const unsigned char *data,
+			   char *tty_flags, int count)
+{
+#ifdef VERBOSE
+	print_hex_dump(KERN_DEBUG, ">in>", DUMP_PREFIX_NONE,
+		16, 1, data, count, 0);
+#endif
+
+	/*
+	 * if fw download is in progress then route incoming data
+	 * to KIM for validation
+	 */
+	st_recv(tty->disc_data, data, count);
+	pr_debug("done %s", __func__);
+}
+
+/*
+ * wake-up function called in from the TTY layer
+ * inside the internal wakeup function will be called
+ */
+static void st_tty_wakeup(struct tty_struct *tty)
+{
+	struct	st_data_s *st_gdata = tty->disc_data;
+	pr_debug("%s ", __func__);
+	/* don't do an wakeup for now */
+	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+
+	/*
+	 * schedule the internal wakeup instead of calling directly to
+	 * avoid lockup (port->lock needed in tty->ops->write is
+	 * already taken here
+	 */
+	schedule_work(&st_gdata->work_write_wakeup);
+}
+
+static void st_tty_flush_buffer(struct tty_struct *tty)
+{
+	struct	st_data_s *st_gdata = tty->disc_data;
+	pr_debug("%s ", __func__);
+
+	kfree_skb(st_gdata->tx_skb);
+	st_gdata->tx_skb = NULL;
+
+	tty_driver_flush_buffer(tty);
+	return;
+}
+
+static struct tty_ldisc_ops st_ldisc_ops = {
+	.magic = TTY_LDISC_MAGIC,
+	.name = "n_st",
+	.open = st_tty_open,
+	.close = st_tty_close,
+	.receive_buf = st_tty_receive,
+	.write_wakeup = st_tty_wakeup,
+	.flush_buffer = st_tty_flush_buffer,
+	.owner = THIS_MODULE
+};
+
+/********************************************************************/
+int st_core_init(struct st_data_s **core_data)
+{
+	struct st_data_s *st_gdata;
+	long err;
+
+	err = tty_register_ldisc(N_TI_WL, &st_ldisc_ops);
+	if (err) {
+		pr_err("error registering %d line discipline %ld",
+			   N_TI_WL, err);
+		return err;
+	}
+	pr_debug("registered n_shared line discipline");
+
+	st_gdata = kzalloc(sizeof(struct st_data_s), GFP_KERNEL);
+	if (!st_gdata) {
+		pr_err("memory allocation failed");
+		err = tty_unregister_ldisc(N_TI_WL);
+		if (err)
+			pr_err("unable to un-register ldisc %ld", err);
+		err = -ENOMEM;
+		return err;
+	}
+
+	/* Initialize ST TxQ and Tx waitQ queue head. All BT/FM/GPS module skb's
+	 * will be pushed in this queue for actual transmission.
+	 */
+	skb_queue_head_init(&st_gdata->txq);
+	skb_queue_head_init(&st_gdata->tx_waitq);
+
+	/* Locking used in st_int_enqueue() to avoid multiple execution */
+	spin_lock_init(&st_gdata->lock);
+
+	err = st_ll_init(st_gdata);
+	if (err) {
+		pr_err("error during st_ll initialization(%ld)", err);
+		kfree(st_gdata);
+		err = tty_unregister_ldisc(N_TI_WL);
+		if (err)
+			pr_err("unable to un-register ldisc");
+		return err;
+	}
+
+	INIT_WORK(&st_gdata->work_write_wakeup, work_fn_write_wakeup);
+
+	*core_data = st_gdata;
+	return 0;
+}
+
+void st_core_exit(struct st_data_s *st_gdata)
+{
+	long err;
+	/* internal module cleanup */
+	err = st_ll_deinit(st_gdata);
+	if (err)
+		pr_err("error during deinit of ST LL %ld", err);
+
+	if (st_gdata != NULL) {
+		/* Free ST Tx Qs and skbs */
+		skb_queue_purge(&st_gdata->txq);
+		skb_queue_purge(&st_gdata->tx_waitq);
+		kfree_skb(st_gdata->rx_skb);
+		kfree_skb(st_gdata->tx_skb);
+		/* TTY ldisc cleanup */
+		err = tty_unregister_ldisc(N_TI_WL);
+		if (err)
+			pr_err("unable to un-register ldisc %ld", err);
+		/* free the global data pointer */
+		kfree(st_gdata);
+	}
+}
diff --git a/drivers/misc/ti-st/st_kim.c b/drivers/misc/ti-st/st_kim.c
new file mode 100644
index 000000000..f2f6cab97
--- /dev/null
+++ b/drivers/misc/ti-st/st_kim.c
@@ -0,0 +1,846 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Shared Transport Line discipline driver Core
+ *	Init Manager module responsible for GPIO control
+ *	and firmware download
+ *  Copyright (C) 2009-2010 Texas Instruments
+ *  Author: Pavan Savoy <pavan_savoy@ti.com>
+ */
+
+#define pr_fmt(fmt) "(stk) :" fmt
+#include <linux/platform_device.h>
+#include <linux/jiffies.h>
+#include <linux/firmware.h>
+#include <linux/delay.h>
+#include <linux/wait.h>
+#include <linux/gpio.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/sched.h>
+#include <linux/sysfs.h>
+#include <linux/tty.h>
+
+#include <linux/skbuff.h>
+#include <linux/ti_wilink_st.h>
+#include <linux/module.h>
+
+#define MAX_ST_DEVICES	3	/* Imagine 1 on each UART for now */
+static struct platform_device *st_kim_devices[MAX_ST_DEVICES];
+
+/**********************************************************************/
+/* internal functions */
+
+/*
+ * st_get_plat_device -
+ *	function which returns the reference to the platform device
+ *	requested by id. As of now only 1 such device exists (id=0)
+ *	the context requesting for reference can get the id to be
+ *	requested by a. The protocol driver which is registering or
+ *	b. the tty device which is opened.
+ */
+static struct platform_device *st_get_plat_device(int id)
+{
+	return st_kim_devices[id];
+}
+
+/*
+ * validate_firmware_response -
+ *	function to return whether the firmware response was proper
+ *	in case of error don't complete so that waiting for proper
+ *	response times out
+ */
+static void validate_firmware_response(struct kim_data_s *kim_gdata)
+{
+	struct sk_buff *skb = kim_gdata->rx_skb;
+	if (!skb)
+		return;
+
+	/*
+	 * these magic numbers are the position in the response buffer which
+	 * allows us to distinguish whether the response is for the read
+	 * version info. command
+	 */
+	if (skb->data[2] == 0x01 && skb->data[3] == 0x01 &&
+			skb->data[4] == 0x10 && skb->data[5] == 0x00) {
+		/* fw version response */
+		memcpy(kim_gdata->resp_buffer,
+				kim_gdata->rx_skb->data,
+				kim_gdata->rx_skb->len);
+		kim_gdata->rx_state = ST_W4_PACKET_TYPE;
+		kim_gdata->rx_skb = NULL;
+		kim_gdata->rx_count = 0;
+	} else if (unlikely(skb->data[5] != 0)) {
+		pr_err("no proper response during fw download");
+		pr_err("data6 %x", skb->data[5]);
+		kfree_skb(skb);
+		return;		/* keep waiting for the proper response */
+	}
+	/* becos of all the script being downloaded */
+	complete_all(&kim_gdata->kim_rcvd);
+	kfree_skb(skb);
+}
+
+/*
+ * check for data len received inside kim_int_recv
+ * most often hit the last case to update state to waiting for data
+ */
+static inline int kim_check_data_len(struct kim_data_s *kim_gdata, int len)
+{
+	register int room = skb_tailroom(kim_gdata->rx_skb);
+
+	pr_debug("len %d room %d", len, room);
+
+	if (!len) {
+		validate_firmware_response(kim_gdata);
+	} else if (len > room) {
+		/*
+		 * Received packet's payload length is larger.
+		 * We can't accommodate it in created skb.
+		 */
+		pr_err("Data length is too large len %d room %d", len,
+			   room);
+		kfree_skb(kim_gdata->rx_skb);
+	} else {
+		/*
+		 * Packet header has non-zero payload length and
+		 * we have enough space in created skb. Lets read
+		 * payload data */
+		kim_gdata->rx_state = ST_W4_DATA;
+		kim_gdata->rx_count = len;
+		return len;
+	}
+
+	/*
+	 * Change ST LL state to continue to process next
+	 * packet
+	 */
+	kim_gdata->rx_state = ST_W4_PACKET_TYPE;
+	kim_gdata->rx_skb = NULL;
+	kim_gdata->rx_count = 0;
+
+	return 0;
+}
+
+/*
+ * kim_int_recv - receive function called during firmware download
+ *	firmware download responses on different UART drivers
+ *	have been observed to come in bursts of different
+ *	tty_receive and hence the logic
+ */
+static void kim_int_recv(struct kim_data_s *kim_gdata,
+	const unsigned char *data, long count)
+{
+	const unsigned char *ptr;
+	int len = 0;
+	unsigned char *plen;
+
+	pr_debug("%s", __func__);
+	/* Decode received bytes here */
+	ptr = data;
+	if (unlikely(ptr == NULL)) {
+		pr_err(" received null from TTY ");
+		return;
+	}
+
+	while (count) {
+		if (kim_gdata->rx_count) {
+			len = min_t(unsigned int, kim_gdata->rx_count, count);
+			skb_put_data(kim_gdata->rx_skb, ptr, len);
+			kim_gdata->rx_count -= len;
+			count -= len;
+			ptr += len;
+
+			if (kim_gdata->rx_count)
+				continue;
+
+			/* Check ST RX state machine , where are we? */
+			switch (kim_gdata->rx_state) {
+				/* Waiting for complete packet ? */
+			case ST_W4_DATA:
+				pr_debug("Complete pkt received");
+				validate_firmware_response(kim_gdata);
+				kim_gdata->rx_state = ST_W4_PACKET_TYPE;
+				kim_gdata->rx_skb = NULL;
+				continue;
+				/* Waiting for Bluetooth event header ? */
+			case ST_W4_HEADER:
+				plen =
+				(unsigned char *)&kim_gdata->rx_skb->data[1];
+				pr_debug("event hdr: plen 0x%02x\n", *plen);
+				kim_check_data_len(kim_gdata, *plen);
+				continue;
+			}	/* end of switch */
+		}		/* end of if rx_state */
+		switch (*ptr) {
+			/* Bluetooth event packet? */
+		case 0x04:
+			kim_gdata->rx_state = ST_W4_HEADER;
+			kim_gdata->rx_count = 2;
+			break;
+		default:
+			pr_info("unknown packet");
+			ptr++;
+			count--;
+			continue;
+		}
+		ptr++;
+		count--;
+		kim_gdata->rx_skb =
+			alloc_skb(1024+8, GFP_ATOMIC);
+		if (!kim_gdata->rx_skb) {
+			pr_err("can't allocate mem for new packet");
+			kim_gdata->rx_state = ST_W4_PACKET_TYPE;
+			kim_gdata->rx_count = 0;
+			return;
+		}
+		skb_reserve(kim_gdata->rx_skb, 8);
+		kim_gdata->rx_skb->cb[0] = 4;
+		kim_gdata->rx_skb->cb[1] = 0;
+
+	}
+	return;
+}
+
+static long read_local_version(struct kim_data_s *kim_gdata, char *bts_scr_name)
+{
+	unsigned short version = 0, chip = 0, min_ver = 0, maj_ver = 0;
+	static const char read_ver_cmd[] = { 0x01, 0x01, 0x10, 0x00 };
+	long timeout;
+
+	pr_debug("%s", __func__);
+
+	reinit_completion(&kim_gdata->kim_rcvd);
+	if (4 != st_int_write(kim_gdata->core_data, read_ver_cmd, 4)) {
+		pr_err("kim: couldn't write 4 bytes");
+		return -EIO;
+	}
+
+	timeout = wait_for_completion_interruptible_timeout(
+		&kim_gdata->kim_rcvd, msecs_to_jiffies(CMD_RESP_TIME));
+	if (timeout <= 0) {
+		pr_err(" waiting for ver info- timed out or received signal");
+		return timeout ? -ERESTARTSYS : -ETIMEDOUT;
+	}
+	reinit_completion(&kim_gdata->kim_rcvd);
+	/*
+	 * the positions 12 & 13 in the response buffer provide with the
+	 * chip, major & minor numbers
+	 */
+
+	version =
+		MAKEWORD(kim_gdata->resp_buffer[12],
+				kim_gdata->resp_buffer[13]);
+	chip = (version & 0x7C00) >> 10;
+	min_ver = (version & 0x007F);
+	maj_ver = (version & 0x0380) >> 7;
+
+	if (version & 0x8000)
+		maj_ver |= 0x0008;
+
+	sprintf(bts_scr_name, "ti-connectivity/TIInit_%d.%d.%d.bts",
+		chip, maj_ver, min_ver);
+
+	/* to be accessed later via sysfs entry */
+	kim_gdata->version.full = version;
+	kim_gdata->version.chip = chip;
+	kim_gdata->version.maj_ver = maj_ver;
+	kim_gdata->version.min_ver = min_ver;
+
+	pr_info("%s", bts_scr_name);
+	return 0;
+}
+
+static void skip_change_remote_baud(unsigned char **ptr, long *len)
+{
+	unsigned char *nxt_action, *cur_action;
+	cur_action = *ptr;
+
+	nxt_action = cur_action + sizeof(struct bts_action) +
+		((struct bts_action *) cur_action)->size;
+
+	if (((struct bts_action *) nxt_action)->type != ACTION_WAIT_EVENT) {
+		pr_err("invalid action after change remote baud command");
+	} else {
+		*ptr = *ptr + sizeof(struct bts_action) +
+			((struct bts_action *)cur_action)->size;
+		*len = *len - (sizeof(struct bts_action) +
+				((struct bts_action *)cur_action)->size);
+		/* warn user on not commenting these in firmware */
+		pr_warn("skipping the wait event of change remote baud");
+	}
+}
+
+/*
+ * download_firmware -
+ *	internal function which parses through the .bts firmware
+ *	script file intreprets SEND, DELAY actions only as of now
+ */
+static long download_firmware(struct kim_data_s *kim_gdata)
+{
+	long err = 0;
+	long len = 0;
+	unsigned char *ptr = NULL;
+	unsigned char *action_ptr = NULL;
+	unsigned char bts_scr_name[40] = { 0 };	/* 40 char long bts scr name? */
+	int wr_room_space;
+	int cmd_size;
+	unsigned long timeout;
+
+	err = read_local_version(kim_gdata, bts_scr_name);
+	if (err != 0) {
+		pr_err("kim: failed to read local ver");
+		return err;
+	}
+	err =
+	    request_firmware(&kim_gdata->fw_entry, bts_scr_name,
+			     &kim_gdata->kim_pdev->dev);
+	if (unlikely((err != 0) || (kim_gdata->fw_entry->data == NULL) ||
+		     (kim_gdata->fw_entry->size == 0))) {
+		pr_err(" request_firmware failed(errno %ld) for %s", err,
+			   bts_scr_name);
+		return -EINVAL;
+	}
+	ptr = (void *)kim_gdata->fw_entry->data;
+	len = kim_gdata->fw_entry->size;
+	/*
+	 * bts_header to remove out magic number and
+	 * version
+	 */
+	ptr += sizeof(struct bts_header);
+	len -= sizeof(struct bts_header);
+
+	while (len > 0 && ptr) {
+		pr_debug(" action size %d, type %d ",
+			   ((struct bts_action *)ptr)->size,
+			   ((struct bts_action *)ptr)->type);
+
+		switch (((struct bts_action *)ptr)->type) {
+		case ACTION_SEND_COMMAND:	/* action send */
+			pr_debug("S");
+			action_ptr = &(((struct bts_action *)ptr)->data[0]);
+			if (unlikely
+			    (((struct hci_command *)action_ptr)->opcode ==
+			     0xFF36)) {
+				/*
+				 * ignore remote change
+				 * baud rate HCI VS command
+				 */
+				pr_warn("change remote baud"
+				    " rate command in firmware");
+				skip_change_remote_baud(&ptr, &len);
+				break;
+			}
+			/*
+			 * Make sure we have enough free space in uart
+			 * tx buffer to write current firmware command
+			 */
+			cmd_size = ((struct bts_action *)ptr)->size;
+			timeout = jiffies + msecs_to_jiffies(CMD_WR_TIME);
+			do {
+				wr_room_space =
+					st_get_uart_wr_room(kim_gdata->core_data);
+				if (wr_room_space < 0) {
+					pr_err("Unable to get free "
+							"space info from uart tx buffer");
+					release_firmware(kim_gdata->fw_entry);
+					return wr_room_space;
+				}
+				mdelay(1); /* wait 1ms before checking room */
+			} while ((wr_room_space < cmd_size) &&
+					time_before(jiffies, timeout));
+
+			/* Timeout happened ? */
+			if (time_after_eq(jiffies, timeout)) {
+				pr_err("Timeout while waiting for free "
+						"free space in uart tx buffer");
+				release_firmware(kim_gdata->fw_entry);
+				return -ETIMEDOUT;
+			}
+			/*
+			 * reinit completion before sending for the
+			 * relevant wait
+			 */
+			reinit_completion(&kim_gdata->kim_rcvd);
+
+			/*
+			 * Free space found in uart buffer, call st_int_write
+			 * to send current firmware command to the uart tx
+			 * buffer.
+			 */
+			err = st_int_write(kim_gdata->core_data,
+			((struct bts_action_send *)action_ptr)->data,
+					   ((struct bts_action *)ptr)->size);
+			if (unlikely(err < 0)) {
+				release_firmware(kim_gdata->fw_entry);
+				return err;
+			}
+			/*
+			 * Check number of bytes written to the uart tx buffer
+			 * and requested command write size
+			 */
+			if (err != cmd_size) {
+				pr_err("Number of bytes written to uart "
+						"tx buffer are not matching with "
+						"requested cmd write size");
+				release_firmware(kim_gdata->fw_entry);
+				return -EIO;
+			}
+			break;
+		case ACTION_WAIT_EVENT:  /* wait */
+			pr_debug("W");
+			err = wait_for_completion_interruptible_timeout(
+					&kim_gdata->kim_rcvd,
+					msecs_to_jiffies(CMD_RESP_TIME));
+			if (err <= 0) {
+				pr_err("response timeout/signaled during fw download ");
+				/* timed out */
+				release_firmware(kim_gdata->fw_entry);
+				return err ? -ERESTARTSYS : -ETIMEDOUT;
+			}
+			reinit_completion(&kim_gdata->kim_rcvd);
+			break;
+		case ACTION_DELAY:	/* sleep */
+			pr_info("sleep command in scr");
+			action_ptr = &(((struct bts_action *)ptr)->data[0]);
+			mdelay(((struct bts_action_delay *)action_ptr)->msec);
+			break;
+		}
+		len =
+		    len - (sizeof(struct bts_action) +
+			   ((struct bts_action *)ptr)->size);
+		ptr =
+		    ptr + sizeof(struct bts_action) +
+		    ((struct bts_action *)ptr)->size;
+	}
+	/* fw download complete */
+	release_firmware(kim_gdata->fw_entry);
+	return 0;
+}
+
+/**********************************************************************/
+/* functions called from ST core */
+/* called from ST Core, when REG_IN_PROGRESS (registration in progress)
+ * can be because of
+ * 1. response to read local version
+ * 2. during send/recv's of firmware download
+ */
+void st_kim_recv(void *disc_data, const unsigned char *data, long count)
+{
+	struct st_data_s	*st_gdata = (struct st_data_s *)disc_data;
+	struct kim_data_s	*kim_gdata = st_gdata->kim_data;
+
+	/*
+	 * proceed to gather all data and distinguish read fw version response
+	 * from other fw responses when data gathering is complete
+	 */
+	kim_int_recv(kim_gdata, data, count);
+	return;
+}
+
+/*
+ * to signal completion of line discipline installation
+ * called from ST Core, upon tty_open
+ */
+void st_kim_complete(void *kim_data)
+{
+	struct kim_data_s	*kim_gdata = (struct kim_data_s *)kim_data;
+	complete(&kim_gdata->ldisc_installed);
+}
+
+/*
+ * st_kim_start - called from ST Core upon 1st registration
+ *	This involves toggling the chip enable gpio, reading
+ *	the firmware version from chip, forming the fw file name
+ *	based on the chip version, requesting the fw, parsing it
+ *	and perform download(send/recv).
+ */
+long st_kim_start(void *kim_data)
+{
+	long err = 0;
+	long retry = POR_RETRY_COUNT;
+	struct ti_st_plat_data	*pdata;
+	struct kim_data_s	*kim_gdata = (struct kim_data_s *)kim_data;
+
+	pr_info(" %s", __func__);
+	pdata = kim_gdata->kim_pdev->dev.platform_data;
+
+	do {
+		/* platform specific enabling code here */
+		if (pdata->chip_enable)
+			pdata->chip_enable(kim_gdata);
+
+		/* Configure BT nShutdown to HIGH state */
+		gpio_set_value_cansleep(kim_gdata->nshutdown, GPIO_LOW);
+		mdelay(5);	/* FIXME: a proper toggle */
+		gpio_set_value_cansleep(kim_gdata->nshutdown, GPIO_HIGH);
+		mdelay(100);
+		/* re-initialize the completion */
+		reinit_completion(&kim_gdata->ldisc_installed);
+		/* send notification to UIM */
+		kim_gdata->ldisc_install = 1;
+		pr_info("ldisc_install = 1");
+		sysfs_notify(&kim_gdata->kim_pdev->dev.kobj,
+				NULL, "install");
+		/* wait for ldisc to be installed */
+		err = wait_for_completion_interruptible_timeout(
+			&kim_gdata->ldisc_installed, msecs_to_jiffies(LDISC_TIME));
+		if (!err) {
+			/*
+			 * ldisc installation timeout,
+			 * flush uart, power cycle BT_EN
+			 */
+			pr_err("ldisc installation timeout");
+			err = st_kim_stop(kim_gdata);
+			continue;
+		} else {
+			/* ldisc installed now */
+			pr_info("line discipline installed");
+			err = download_firmware(kim_gdata);
+			if (err != 0) {
+				/*
+				 * ldisc installed but fw download failed,
+				 * flush uart & power cycle BT_EN
+				 */
+				pr_err("download firmware failed");
+				err = st_kim_stop(kim_gdata);
+				continue;
+			} else {	/* on success don't retry */
+				break;
+			}
+		}
+	} while (retry--);
+	return err;
+}
+
+/*
+ * st_kim_stop - stop communication with chip.
+ *	This can be called from ST Core/KIM, on the-
+ *	(a) last un-register when chip need not be powered there-after,
+ *	(b) upon failure to either install ldisc or download firmware.
+ *	The function is responsible to (a) notify UIM about un-installation,
+ *	(b) flush UART if the ldisc was installed.
+ *	(c) reset BT_EN - pull down nshutdown at the end.
+ *	(d) invoke platform's chip disabling routine.
+ */
+long st_kim_stop(void *kim_data)
+{
+	long err = 0;
+	struct kim_data_s	*kim_gdata = (struct kim_data_s *)kim_data;
+	struct ti_st_plat_data	*pdata =
+		kim_gdata->kim_pdev->dev.platform_data;
+	struct tty_struct	*tty = kim_gdata->core_data->tty;
+
+	reinit_completion(&kim_gdata->ldisc_installed);
+
+	if (tty) {	/* can be called before ldisc is installed */
+		/* Flush any pending characters in the driver and discipline. */
+		tty_ldisc_flush(tty);
+		tty_driver_flush_buffer(tty);
+	}
+
+	/* send uninstall notification to UIM */
+	pr_info("ldisc_install = 0");
+	kim_gdata->ldisc_install = 0;
+	sysfs_notify(&kim_gdata->kim_pdev->dev.kobj, NULL, "install");
+
+	/* wait for ldisc to be un-installed */
+	err = wait_for_completion_interruptible_timeout(
+		&kim_gdata->ldisc_installed, msecs_to_jiffies(LDISC_TIME));
+	if (!err) {		/* timeout */
+		pr_err(" timed out waiting for ldisc to be un-installed");
+		err = -ETIMEDOUT;
+	}
+
+	/* By default configure BT nShutdown to LOW state */
+	gpio_set_value_cansleep(kim_gdata->nshutdown, GPIO_LOW);
+	mdelay(1);
+	gpio_set_value_cansleep(kim_gdata->nshutdown, GPIO_HIGH);
+	mdelay(1);
+	gpio_set_value_cansleep(kim_gdata->nshutdown, GPIO_LOW);
+
+	/* platform specific disable */
+	if (pdata->chip_disable)
+		pdata->chip_disable(kim_gdata);
+	return err;
+}
+
+/**********************************************************************/
+/* functions called from subsystems */
+/* called when debugfs entry is read from */
+
+static int version_show(struct seq_file *s, void *unused)
+{
+	struct kim_data_s *kim_gdata = (struct kim_data_s *)s->private;
+	seq_printf(s, "%04X %d.%d.%d\n", kim_gdata->version.full,
+			kim_gdata->version.chip, kim_gdata->version.maj_ver,
+			kim_gdata->version.min_ver);
+	return 0;
+}
+
+static int list_show(struct seq_file *s, void *unused)
+{
+	struct kim_data_s *kim_gdata = (struct kim_data_s *)s->private;
+	kim_st_list_protocols(kim_gdata->core_data, s);
+	return 0;
+}
+
+static ssize_t show_install(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct kim_data_s *kim_data = dev_get_drvdata(dev);
+	return sprintf(buf, "%d\n", kim_data->ldisc_install);
+}
+
+#ifdef DEBUG
+static ssize_t store_dev_name(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct kim_data_s *kim_data = dev_get_drvdata(dev);
+	pr_debug("storing dev name >%s<", buf);
+	strncpy(kim_data->dev_name, buf, count);
+	pr_debug("stored dev name >%s<", kim_data->dev_name);
+	return count;
+}
+
+static ssize_t store_baud_rate(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct kim_data_s *kim_data = dev_get_drvdata(dev);
+	pr_debug("storing baud rate >%s<", buf);
+	sscanf(buf, "%ld", &kim_data->baud_rate);
+	pr_debug("stored baud rate >%ld<", kim_data->baud_rate);
+	return count;
+}
+#endif	/* if DEBUG */
+
+static ssize_t show_dev_name(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct kim_data_s *kim_data = dev_get_drvdata(dev);
+	return sprintf(buf, "%s\n", kim_data->dev_name);
+}
+
+static ssize_t show_baud_rate(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct kim_data_s *kim_data = dev_get_drvdata(dev);
+	return sprintf(buf, "%d\n", kim_data->baud_rate);
+}
+
+static ssize_t show_flow_cntrl(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct kim_data_s *kim_data = dev_get_drvdata(dev);
+	return sprintf(buf, "%d\n", kim_data->flow_cntrl);
+}
+
+/* structures specific for sysfs entries */
+static struct kobj_attribute ldisc_install =
+__ATTR(install, 0444, (void *)show_install, NULL);
+
+static struct kobj_attribute uart_dev_name =
+#ifdef DEBUG	/* TODO: move this to debug-fs if possible */
+__ATTR(dev_name, 0644, (void *)show_dev_name, (void *)store_dev_name);
+#else
+__ATTR(dev_name, 0444, (void *)show_dev_name, NULL);
+#endif
+
+static struct kobj_attribute uart_baud_rate =
+#ifdef DEBUG	/* TODO: move to debugfs */
+__ATTR(baud_rate, 0644, (void *)show_baud_rate, (void *)store_baud_rate);
+#else
+__ATTR(baud_rate, 0444, (void *)show_baud_rate, NULL);
+#endif
+
+static struct kobj_attribute uart_flow_cntrl =
+__ATTR(flow_cntrl, 0444, (void *)show_flow_cntrl, NULL);
+
+static struct attribute *uim_attrs[] = {
+	&ldisc_install.attr,
+	&uart_dev_name.attr,
+	&uart_baud_rate.attr,
+	&uart_flow_cntrl.attr,
+	NULL,
+};
+
+static const struct attribute_group uim_attr_grp = {
+	.attrs = uim_attrs,
+};
+
+/*
+ * st_kim_ref - reference the core's data
+ *	This references the per-ST platform device in the arch/xx/
+ *	board-xx.c file.
+ *	This would enable multiple such platform devices to exist
+ *	on a given platform
+ */
+void st_kim_ref(struct st_data_s **core_data, int id)
+{
+	struct platform_device	*pdev;
+	struct kim_data_s	*kim_gdata;
+	/* get kim_gdata reference from platform device */
+	pdev = st_get_plat_device(id);
+	if (!pdev)
+		goto err;
+	kim_gdata = platform_get_drvdata(pdev);
+	if (!kim_gdata)
+		goto err;
+
+	*core_data = kim_gdata->core_data;
+	return;
+err:
+	*core_data = NULL;
+}
+
+DEFINE_SHOW_ATTRIBUTE(version);
+DEFINE_SHOW_ATTRIBUTE(list);
+
+/**********************************************************************/
+/* functions called from platform device driver subsystem
+ * need to have a relevant platform device entry in the platform's
+ * board-*.c file
+ */
+
+static struct dentry *kim_debugfs_dir;
+static int kim_probe(struct platform_device *pdev)
+{
+	struct kim_data_s	*kim_gdata;
+	struct ti_st_plat_data	*pdata = pdev->dev.platform_data;
+	int err;
+
+	if ((pdev->id != -1) && (pdev->id < MAX_ST_DEVICES)) {
+		/* multiple devices could exist */
+		st_kim_devices[pdev->id] = pdev;
+	} else {
+		/* platform's sure about existence of 1 device */
+		st_kim_devices[0] = pdev;
+	}
+
+	kim_gdata = kzalloc(sizeof(struct kim_data_s), GFP_KERNEL);
+	if (!kim_gdata) {
+		pr_err("no mem to allocate");
+		return -ENOMEM;
+	}
+	platform_set_drvdata(pdev, kim_gdata);
+
+	err = st_core_init(&kim_gdata->core_data);
+	if (err != 0) {
+		pr_err(" ST core init failed");
+		err = -EIO;
+		goto err_core_init;
+	}
+	/* refer to itself */
+	kim_gdata->core_data->kim_data = kim_gdata;
+
+	/* Claim the chip enable nShutdown gpio from the system */
+	kim_gdata->nshutdown = pdata->nshutdown_gpio;
+	err = gpio_request(kim_gdata->nshutdown, "kim");
+	if (unlikely(err)) {
+		pr_err(" gpio %d request failed ", kim_gdata->nshutdown);
+		goto err_sysfs_group;
+	}
+
+	/* Configure nShutdown GPIO as output=0 */
+	err = gpio_direction_output(kim_gdata->nshutdown, 0);
+	if (unlikely(err)) {
+		pr_err(" unable to configure gpio %d", kim_gdata->nshutdown);
+		goto err_sysfs_group;
+	}
+	/* get reference of pdev for request_firmware */
+	kim_gdata->kim_pdev = pdev;
+	init_completion(&kim_gdata->kim_rcvd);
+	init_completion(&kim_gdata->ldisc_installed);
+
+	err = sysfs_create_group(&pdev->dev.kobj, &uim_attr_grp);
+	if (err) {
+		pr_err("failed to create sysfs entries");
+		goto err_sysfs_group;
+	}
+
+	/* copying platform data */
+	strncpy(kim_gdata->dev_name, pdata->dev_name, UART_DEV_NAME_LEN);
+	kim_gdata->flow_cntrl = pdata->flow_cntrl;
+	kim_gdata->baud_rate = pdata->baud_rate;
+	pr_info("sysfs entries created\n");
+
+	kim_debugfs_dir = debugfs_create_dir("ti-st", NULL);
+
+	debugfs_create_file("version", S_IRUGO, kim_debugfs_dir,
+				kim_gdata, &version_fops);
+	debugfs_create_file("protocols", S_IRUGO, kim_debugfs_dir,
+				kim_gdata, &list_fops);
+	return 0;
+
+err_sysfs_group:
+	st_core_exit(kim_gdata->core_data);
+
+err_core_init:
+	kfree(kim_gdata);
+
+	return err;
+}
+
+static int kim_remove(struct platform_device *pdev)
+{
+	/* free the GPIOs requested */
+	struct ti_st_plat_data	*pdata = pdev->dev.platform_data;
+	struct kim_data_s	*kim_gdata;
+
+	kim_gdata = platform_get_drvdata(pdev);
+
+	/*
+	 * Free the Bluetooth/FM/GPIO
+	 * nShutdown gpio from the system
+	 */
+	gpio_free(pdata->nshutdown_gpio);
+	pr_info("nshutdown GPIO Freed");
+
+	debugfs_remove_recursive(kim_debugfs_dir);
+	sysfs_remove_group(&pdev->dev.kobj, &uim_attr_grp);
+	pr_info("sysfs entries removed");
+
+	kim_gdata->kim_pdev = NULL;
+	st_core_exit(kim_gdata->core_data);
+
+	kfree(kim_gdata);
+	kim_gdata = NULL;
+	return 0;
+}
+
+static int kim_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	struct ti_st_plat_data	*pdata = pdev->dev.platform_data;
+
+	if (pdata->suspend)
+		return pdata->suspend(pdev, state);
+
+	return 0;
+}
+
+static int kim_resume(struct platform_device *pdev)
+{
+	struct ti_st_plat_data	*pdata = pdev->dev.platform_data;
+
+	if (pdata->resume)
+		return pdata->resume(pdev);
+
+	return 0;
+}
+
+/**********************************************************************/
+/* entry point for ST KIM module, called in from ST Core */
+static struct platform_driver kim_platform_driver = {
+	.probe = kim_probe,
+	.remove = kim_remove,
+	.suspend = kim_suspend,
+	.resume = kim_resume,
+	.driver = {
+		.name = "kim",
+	},
+};
+
+module_platform_driver(kim_platform_driver);
+
+MODULE_AUTHOR("Pavan Savoy <pavan_savoy@ti.com>");
+MODULE_DESCRIPTION("Shared Transport Driver for TI BT/FM/GPS combo chips ");
+MODULE_LICENSE("GPL");
diff --git a/drivers/misc/ti-st/st_ll.c b/drivers/misc/ti-st/st_ll.c
new file mode 100644
index 000000000..07406140d
--- /dev/null
+++ b/drivers/misc/ti-st/st_ll.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Shared Transport driver
+ *	HCI-LL module responsible for TI proprietary HCI_LL protocol
+ *  Copyright (C) 2009-2010 Texas Instruments
+ *  Author: Pavan Savoy <pavan_savoy@ti.com>
+ */
+
+#define pr_fmt(fmt) "(stll) :" fmt
+#include <linux/skbuff.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/ti_wilink_st.h>
+
+/**********************************************************************/
+/* internal functions */
+static void send_ll_cmd(struct st_data_s *st_data,
+	unsigned char cmd)
+{
+
+	pr_debug("%s: writing %x", __func__, cmd);
+	st_int_write(st_data, &cmd, 1);
+	return;
+}
+
+static void ll_device_want_to_sleep(struct st_data_s *st_data)
+{
+	struct kim_data_s	*kim_data;
+	struct ti_st_plat_data	*pdata;
+
+	pr_debug("%s", __func__);
+	/* sanity check */
+	if (st_data->ll_state != ST_LL_AWAKE)
+		pr_err("ERR hcill: ST_LL_GO_TO_SLEEP_IND"
+			  "in state %ld", st_data->ll_state);
+
+	send_ll_cmd(st_data, LL_SLEEP_ACK);
+	/* update state */
+	st_data->ll_state = ST_LL_ASLEEP;
+
+	/* communicate to platform about chip asleep */
+	kim_data = st_data->kim_data;
+	pdata = kim_data->kim_pdev->dev.platform_data;
+	if (pdata->chip_asleep)
+		pdata->chip_asleep(NULL);
+}
+
+static void ll_device_want_to_wakeup(struct st_data_s *st_data)
+{
+	struct kim_data_s	*kim_data;
+	struct ti_st_plat_data	*pdata;
+
+	/* diff actions in diff states */
+	switch (st_data->ll_state) {
+	case ST_LL_ASLEEP:
+		send_ll_cmd(st_data, LL_WAKE_UP_ACK);	/* send wake_ack */
+		break;
+	case ST_LL_ASLEEP_TO_AWAKE:
+		/* duplicate wake_ind */
+		pr_err("duplicate wake_ind while waiting for Wake ack");
+		break;
+	case ST_LL_AWAKE:
+		/* duplicate wake_ind */
+		pr_err("duplicate wake_ind already AWAKE");
+		break;
+	case ST_LL_AWAKE_TO_ASLEEP:
+		/* duplicate wake_ind */
+		pr_err("duplicate wake_ind");
+		break;
+	}
+	/* update state */
+	st_data->ll_state = ST_LL_AWAKE;
+
+	/* communicate to platform about chip wakeup */
+	kim_data = st_data->kim_data;
+	pdata = kim_data->kim_pdev->dev.platform_data;
+	if (pdata->chip_awake)
+		pdata->chip_awake(NULL);
+}
+
+/**********************************************************************/
+/* functions invoked by ST Core */
+
+/* called when ST Core wants to
+ * enable ST LL */
+void st_ll_enable(struct st_data_s *ll)
+{
+	ll->ll_state = ST_LL_AWAKE;
+}
+
+/* called when ST Core /local module wants to
+ * disable ST LL */
+void st_ll_disable(struct st_data_s *ll)
+{
+	ll->ll_state = ST_LL_INVALID;
+}
+
+/* called when ST Core wants to update the state */
+void st_ll_wakeup(struct st_data_s *ll)
+{
+	if (likely(ll->ll_state != ST_LL_AWAKE)) {
+		send_ll_cmd(ll, LL_WAKE_UP_IND);	/* WAKE_IND */
+		ll->ll_state = ST_LL_ASLEEP_TO_AWAKE;
+	} else {
+		/* don't send the duplicate wake_indication */
+		pr_err(" Chip already AWAKE ");
+	}
+}
+
+/* called when ST Core wants the state */
+unsigned long st_ll_getstate(struct st_data_s *ll)
+{
+	pr_debug(" returning state %ld", ll->ll_state);
+	return ll->ll_state;
+}
+
+/* called from ST Core, when a PM related packet arrives */
+unsigned long st_ll_sleep_state(struct st_data_s *st_data,
+	unsigned char cmd)
+{
+	switch (cmd) {
+	case LL_SLEEP_IND:	/* sleep ind */
+		pr_debug("sleep indication recvd");
+		ll_device_want_to_sleep(st_data);
+		break;
+	case LL_SLEEP_ACK:	/* sleep ack */
+		pr_err("sleep ack rcvd: host shouldn't");
+		break;
+	case LL_WAKE_UP_IND:	/* wake ind */
+		pr_debug("wake indication recvd");
+		ll_device_want_to_wakeup(st_data);
+		break;
+	case LL_WAKE_UP_ACK:	/* wake ack */
+		pr_debug("wake ack rcvd");
+		st_data->ll_state = ST_LL_AWAKE;
+		break;
+	default:
+		pr_err(" unknown input/state ");
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/* Called from ST CORE to initialize ST LL */
+long st_ll_init(struct st_data_s *ll)
+{
+	/* set state to invalid */
+	ll->ll_state = ST_LL_INVALID;
+	return 0;
+}
+
+/* Called from ST CORE to de-initialize ST LL */
+long st_ll_deinit(struct st_data_s *ll)
+{
+	return 0;
+}