Adding upstream version 6.1.76.upstream/6.1.76upstream

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

1 files changed, 1060 insertions, 0 deletions

diff --git a/drivers/firmware/arm_scpi.c b/drivers/firmware/arm_scpi.c
new file mode 100644
index 000000000..435d0e265
--- /dev/null
+++ b/drivers/firmware/arm_scpi.c
@@ -0,0 +1,1060 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * System Control and Power Interface (SCPI) Message Protocol driver
+ *
+ * SCPI Message Protocol is used between the System Control Processor(SCP)
+ * and the Application Processors(AP). The Message Handling Unit(MHU)
+ * provides a mechanism for inter-processor communication between SCP's
+ * Cortex M3 and AP.
+ *
+ * SCP offers control and management of the core/cluster power states,
+ * various power domain DVFS including the core/cluster, certain system
+ * clocks configuration, thermal sensors and many others.
+ *
+ * Copyright (C) 2015 ARM Ltd.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/bitmap.h>
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/printk.h>
+#include <linux/pm_opp.h>
+#include <linux/scpi_protocol.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+#include <linux/spinlock.h>
+
+#define CMD_ID_MASK		GENMASK(6, 0)
+#define CMD_TOKEN_ID_MASK	GENMASK(15, 8)
+#define CMD_DATA_SIZE_MASK	GENMASK(24, 16)
+#define CMD_LEGACY_DATA_SIZE_MASK	GENMASK(28, 20)
+#define PACK_SCPI_CMD(cmd_id, tx_sz)		\
+	(FIELD_PREP(CMD_ID_MASK, cmd_id) |	\
+	FIELD_PREP(CMD_DATA_SIZE_MASK, tx_sz))
+#define PACK_LEGACY_SCPI_CMD(cmd_id, tx_sz)	\
+	(FIELD_PREP(CMD_ID_MASK, cmd_id) |	\
+	FIELD_PREP(CMD_LEGACY_DATA_SIZE_MASK, tx_sz))
+
+#define CMD_SIZE(cmd)	FIELD_GET(CMD_DATA_SIZE_MASK, cmd)
+#define CMD_UNIQ_MASK	(CMD_TOKEN_ID_MASK | CMD_ID_MASK)
+#define CMD_XTRACT_UNIQ(cmd)	((cmd) & CMD_UNIQ_MASK)
+
+#define SCPI_SLOT		0
+
+#define MAX_DVFS_DOMAINS	8
+#define MAX_DVFS_OPPS		16
+
+#define PROTO_REV_MAJOR_MASK	GENMASK(31, 16)
+#define PROTO_REV_MINOR_MASK	GENMASK(15, 0)
+
+#define FW_REV_MAJOR_MASK	GENMASK(31, 24)
+#define FW_REV_MINOR_MASK	GENMASK(23, 16)
+#define FW_REV_PATCH_MASK	GENMASK(15, 0)
+
+#define MAX_RX_TIMEOUT		(msecs_to_jiffies(30))
+
+enum scpi_error_codes {
+	SCPI_SUCCESS = 0, /* Success */
+	SCPI_ERR_PARAM = 1, /* Invalid parameter(s) */
+	SCPI_ERR_ALIGN = 2, /* Invalid alignment */
+	SCPI_ERR_SIZE = 3, /* Invalid size */
+	SCPI_ERR_HANDLER = 4, /* Invalid handler/callback */
+	SCPI_ERR_ACCESS = 5, /* Invalid access/permission denied */
+	SCPI_ERR_RANGE = 6, /* Value out of range */
+	SCPI_ERR_TIMEOUT = 7, /* Timeout has occurred */
+	SCPI_ERR_NOMEM = 8, /* Invalid memory area or pointer */
+	SCPI_ERR_PWRSTATE = 9, /* Invalid power state */
+	SCPI_ERR_SUPPORT = 10, /* Not supported or disabled */
+	SCPI_ERR_DEVICE = 11, /* Device error */
+	SCPI_ERR_BUSY = 12, /* Device busy */
+	SCPI_ERR_MAX
+};
+
+/* SCPI Standard commands */
+enum scpi_std_cmd {
+	SCPI_CMD_INVALID		= 0x00,
+	SCPI_CMD_SCPI_READY		= 0x01,
+	SCPI_CMD_SCPI_CAPABILITIES	= 0x02,
+	SCPI_CMD_SET_CSS_PWR_STATE	= 0x03,
+	SCPI_CMD_GET_CSS_PWR_STATE	= 0x04,
+	SCPI_CMD_SET_SYS_PWR_STATE	= 0x05,
+	SCPI_CMD_SET_CPU_TIMER		= 0x06,
+	SCPI_CMD_CANCEL_CPU_TIMER	= 0x07,
+	SCPI_CMD_DVFS_CAPABILITIES	= 0x08,
+	SCPI_CMD_GET_DVFS_INFO		= 0x09,
+	SCPI_CMD_SET_DVFS		= 0x0a,
+	SCPI_CMD_GET_DVFS		= 0x0b,
+	SCPI_CMD_GET_DVFS_STAT		= 0x0c,
+	SCPI_CMD_CLOCK_CAPABILITIES	= 0x0d,
+	SCPI_CMD_GET_CLOCK_INFO		= 0x0e,
+	SCPI_CMD_SET_CLOCK_VALUE	= 0x0f,
+	SCPI_CMD_GET_CLOCK_VALUE	= 0x10,
+	SCPI_CMD_PSU_CAPABILITIES	= 0x11,
+	SCPI_CMD_GET_PSU_INFO		= 0x12,
+	SCPI_CMD_SET_PSU		= 0x13,
+	SCPI_CMD_GET_PSU		= 0x14,
+	SCPI_CMD_SENSOR_CAPABILITIES	= 0x15,
+	SCPI_CMD_SENSOR_INFO		= 0x16,
+	SCPI_CMD_SENSOR_VALUE		= 0x17,
+	SCPI_CMD_SENSOR_CFG_PERIODIC	= 0x18,
+	SCPI_CMD_SENSOR_CFG_BOUNDS	= 0x19,
+	SCPI_CMD_SENSOR_ASYNC_VALUE	= 0x1a,
+	SCPI_CMD_SET_DEVICE_PWR_STATE	= 0x1b,
+	SCPI_CMD_GET_DEVICE_PWR_STATE	= 0x1c,
+	SCPI_CMD_COUNT
+};
+
+/* SCPI Legacy Commands */
+enum legacy_scpi_std_cmd {
+	LEGACY_SCPI_CMD_INVALID			= 0x00,
+	LEGACY_SCPI_CMD_SCPI_READY		= 0x01,
+	LEGACY_SCPI_CMD_SCPI_CAPABILITIES	= 0x02,
+	LEGACY_SCPI_CMD_EVENT			= 0x03,
+	LEGACY_SCPI_CMD_SET_CSS_PWR_STATE	= 0x04,
+	LEGACY_SCPI_CMD_GET_CSS_PWR_STATE	= 0x05,
+	LEGACY_SCPI_CMD_CFG_PWR_STATE_STAT	= 0x06,
+	LEGACY_SCPI_CMD_GET_PWR_STATE_STAT	= 0x07,
+	LEGACY_SCPI_CMD_SYS_PWR_STATE		= 0x08,
+	LEGACY_SCPI_CMD_L2_READY		= 0x09,
+	LEGACY_SCPI_CMD_SET_AP_TIMER		= 0x0a,
+	LEGACY_SCPI_CMD_CANCEL_AP_TIME		= 0x0b,
+	LEGACY_SCPI_CMD_DVFS_CAPABILITIES	= 0x0c,
+	LEGACY_SCPI_CMD_GET_DVFS_INFO		= 0x0d,
+	LEGACY_SCPI_CMD_SET_DVFS		= 0x0e,
+	LEGACY_SCPI_CMD_GET_DVFS		= 0x0f,
+	LEGACY_SCPI_CMD_GET_DVFS_STAT		= 0x10,
+	LEGACY_SCPI_CMD_SET_RTC			= 0x11,
+	LEGACY_SCPI_CMD_GET_RTC			= 0x12,
+	LEGACY_SCPI_CMD_CLOCK_CAPABILITIES	= 0x13,
+	LEGACY_SCPI_CMD_SET_CLOCK_INDEX		= 0x14,
+	LEGACY_SCPI_CMD_SET_CLOCK_VALUE		= 0x15,
+	LEGACY_SCPI_CMD_GET_CLOCK_VALUE		= 0x16,
+	LEGACY_SCPI_CMD_PSU_CAPABILITIES	= 0x17,
+	LEGACY_SCPI_CMD_SET_PSU			= 0x18,
+	LEGACY_SCPI_CMD_GET_PSU			= 0x19,
+	LEGACY_SCPI_CMD_SENSOR_CAPABILITIES	= 0x1a,
+	LEGACY_SCPI_CMD_SENSOR_INFO		= 0x1b,
+	LEGACY_SCPI_CMD_SENSOR_VALUE		= 0x1c,
+	LEGACY_SCPI_CMD_SENSOR_CFG_PERIODIC	= 0x1d,
+	LEGACY_SCPI_CMD_SENSOR_CFG_BOUNDS	= 0x1e,
+	LEGACY_SCPI_CMD_SENSOR_ASYNC_VALUE	= 0x1f,
+	LEGACY_SCPI_CMD_COUNT
+};
+
+/* List all commands that are required to go through the high priority link */
+static int legacy_hpriority_cmds[] = {
+	LEGACY_SCPI_CMD_GET_CSS_PWR_STATE,
+	LEGACY_SCPI_CMD_CFG_PWR_STATE_STAT,
+	LEGACY_SCPI_CMD_GET_PWR_STATE_STAT,
+	LEGACY_SCPI_CMD_SET_DVFS,
+	LEGACY_SCPI_CMD_GET_DVFS,
+	LEGACY_SCPI_CMD_SET_RTC,
+	LEGACY_SCPI_CMD_GET_RTC,
+	LEGACY_SCPI_CMD_SET_CLOCK_INDEX,
+	LEGACY_SCPI_CMD_SET_CLOCK_VALUE,
+	LEGACY_SCPI_CMD_GET_CLOCK_VALUE,
+	LEGACY_SCPI_CMD_SET_PSU,
+	LEGACY_SCPI_CMD_GET_PSU,
+	LEGACY_SCPI_CMD_SENSOR_CFG_PERIODIC,
+	LEGACY_SCPI_CMD_SENSOR_CFG_BOUNDS,
+};
+
+/* List all commands used by this driver, used as indexes */
+enum scpi_drv_cmds {
+	CMD_SCPI_CAPABILITIES = 0,
+	CMD_GET_CLOCK_INFO,
+	CMD_GET_CLOCK_VALUE,
+	CMD_SET_CLOCK_VALUE,
+	CMD_GET_DVFS,
+	CMD_SET_DVFS,
+	CMD_GET_DVFS_INFO,
+	CMD_SENSOR_CAPABILITIES,
+	CMD_SENSOR_INFO,
+	CMD_SENSOR_VALUE,
+	CMD_SET_DEVICE_PWR_STATE,
+	CMD_GET_DEVICE_PWR_STATE,
+	CMD_MAX_COUNT,
+};
+
+static int scpi_std_commands[CMD_MAX_COUNT] = {
+	SCPI_CMD_SCPI_CAPABILITIES,
+	SCPI_CMD_GET_CLOCK_INFO,
+	SCPI_CMD_GET_CLOCK_VALUE,
+	SCPI_CMD_SET_CLOCK_VALUE,
+	SCPI_CMD_GET_DVFS,
+	SCPI_CMD_SET_DVFS,
+	SCPI_CMD_GET_DVFS_INFO,
+	SCPI_CMD_SENSOR_CAPABILITIES,
+	SCPI_CMD_SENSOR_INFO,
+	SCPI_CMD_SENSOR_VALUE,
+	SCPI_CMD_SET_DEVICE_PWR_STATE,
+	SCPI_CMD_GET_DEVICE_PWR_STATE,
+};
+
+static int scpi_legacy_commands[CMD_MAX_COUNT] = {
+	LEGACY_SCPI_CMD_SCPI_CAPABILITIES,
+	-1, /* GET_CLOCK_INFO */
+	LEGACY_SCPI_CMD_GET_CLOCK_VALUE,
+	LEGACY_SCPI_CMD_SET_CLOCK_VALUE,
+	LEGACY_SCPI_CMD_GET_DVFS,
+	LEGACY_SCPI_CMD_SET_DVFS,
+	LEGACY_SCPI_CMD_GET_DVFS_INFO,
+	LEGACY_SCPI_CMD_SENSOR_CAPABILITIES,
+	LEGACY_SCPI_CMD_SENSOR_INFO,
+	LEGACY_SCPI_CMD_SENSOR_VALUE,
+	-1, /* SET_DEVICE_PWR_STATE */
+	-1, /* GET_DEVICE_PWR_STATE */
+};
+
+struct scpi_xfer {
+	u32 slot; /* has to be first element */
+	u32 cmd;
+	u32 status;
+	const void *tx_buf;
+	void *rx_buf;
+	unsigned int tx_len;
+	unsigned int rx_len;
+	struct list_head node;
+	struct completion done;
+};
+
+struct scpi_chan {
+	struct mbox_client cl;
+	struct mbox_chan *chan;
+	void __iomem *tx_payload;
+	void __iomem *rx_payload;
+	struct list_head rx_pending;
+	struct list_head xfers_list;
+	struct scpi_xfer *xfers;
+	spinlock_t rx_lock; /* locking for the rx pending list */
+	struct mutex xfers_lock;
+	u8 token;
+};
+
+struct scpi_drvinfo {
+	u32 protocol_version;
+	u32 firmware_version;
+	bool is_legacy;
+	int num_chans;
+	int *commands;
+	DECLARE_BITMAP(cmd_priority, LEGACY_SCPI_CMD_COUNT);
+	atomic_t next_chan;
+	struct scpi_ops *scpi_ops;
+	struct scpi_chan *channels;
+	struct scpi_dvfs_info *dvfs[MAX_DVFS_DOMAINS];
+};
+
+/*
+ * The SCP firmware only executes in little-endian mode, so any buffers
+ * shared through SCPI should have their contents converted to little-endian
+ */
+struct scpi_shared_mem {
+	__le32 command;
+	__le32 status;
+	u8 payload[];
+} __packed;
+
+struct legacy_scpi_shared_mem {
+	__le32 status;
+	u8 payload[];
+} __packed;
+
+struct scp_capabilities {
+	__le32 protocol_version;
+	__le32 event_version;
+	__le32 platform_version;
+	__le32 commands[4];
+} __packed;
+
+struct clk_get_info {
+	__le16 id;
+	__le16 flags;
+	__le32 min_rate;
+	__le32 max_rate;
+	u8 name[20];
+} __packed;
+
+struct clk_set_value {
+	__le16 id;
+	__le16 reserved;
+	__le32 rate;
+} __packed;
+
+struct legacy_clk_set_value {
+	__le32 rate;
+	__le16 id;
+	__le16 reserved;
+} __packed;
+
+struct dvfs_info {
+	u8 domain;
+	u8 opp_count;
+	__le16 latency;
+	struct {
+		__le32 freq;
+		__le32 m_volt;
+	} opps[MAX_DVFS_OPPS];
+} __packed;
+
+struct dvfs_set {
+	u8 domain;
+	u8 index;
+} __packed;
+
+struct _scpi_sensor_info {
+	__le16 sensor_id;
+	u8 class;
+	u8 trigger_type;
+	char name[20];
+};
+
+struct dev_pstate_set {
+	__le16 dev_id;
+	u8 pstate;
+} __packed;
+
+static struct scpi_drvinfo *scpi_info;
+
+static int scpi_linux_errmap[SCPI_ERR_MAX] = {
+	/* better than switch case as long as return value is continuous */
+	0, /* SCPI_SUCCESS */
+	-EINVAL, /* SCPI_ERR_PARAM */
+	-ENOEXEC, /* SCPI_ERR_ALIGN */
+	-EMSGSIZE, /* SCPI_ERR_SIZE */
+	-EINVAL, /* SCPI_ERR_HANDLER */
+	-EACCES, /* SCPI_ERR_ACCESS */
+	-ERANGE, /* SCPI_ERR_RANGE */
+	-ETIMEDOUT, /* SCPI_ERR_TIMEOUT */
+	-ENOMEM, /* SCPI_ERR_NOMEM */
+	-EINVAL, /* SCPI_ERR_PWRSTATE */
+	-EOPNOTSUPP, /* SCPI_ERR_SUPPORT */
+	-EIO, /* SCPI_ERR_DEVICE */
+	-EBUSY, /* SCPI_ERR_BUSY */
+};
+
+static inline int scpi_to_linux_errno(int errno)
+{
+	if (errno >= SCPI_SUCCESS && errno < SCPI_ERR_MAX)
+		return scpi_linux_errmap[errno];
+	return -EIO;
+}
+
+static void scpi_process_cmd(struct scpi_chan *ch, u32 cmd)
+{
+	unsigned long flags;
+	struct scpi_xfer *t, *match = NULL;
+
+	spin_lock_irqsave(&ch->rx_lock, flags);
+	if (list_empty(&ch->rx_pending)) {
+		spin_unlock_irqrestore(&ch->rx_lock, flags);
+		return;
+	}
+
+	/* Command type is not replied by the SCP Firmware in legacy Mode
+	 * We should consider that command is the head of pending RX commands
+	 * if the list is not empty. In TX only mode, the list would be empty.
+	 */
+	if (scpi_info->is_legacy) {
+		match = list_first_entry(&ch->rx_pending, struct scpi_xfer,
+					 node);
+		list_del(&match->node);
+	} else {
+		list_for_each_entry(t, &ch->rx_pending, node)
+			if (CMD_XTRACT_UNIQ(t->cmd) == CMD_XTRACT_UNIQ(cmd)) {
+				list_del(&t->node);
+				match = t;
+				break;
+			}
+	}
+	/* check if wait_for_completion is in progress or timed-out */
+	if (match && !completion_done(&match->done)) {
+		unsigned int len;
+
+		if (scpi_info->is_legacy) {
+			struct legacy_scpi_shared_mem __iomem *mem =
+							ch->rx_payload;
+
+			/* RX Length is not replied by the legacy Firmware */
+			len = match->rx_len;
+
+			match->status = ioread32(&mem->status);
+			memcpy_fromio(match->rx_buf, mem->payload, len);
+		} else {
+			struct scpi_shared_mem __iomem *mem = ch->rx_payload;
+
+			len = min_t(unsigned int, match->rx_len, CMD_SIZE(cmd));
+
+			match->status = ioread32(&mem->status);
+			memcpy_fromio(match->rx_buf, mem->payload, len);
+		}
+
+		if (match->rx_len > len)
+			memset(match->rx_buf + len, 0, match->rx_len - len);
+		complete(&match->done);
+	}
+	spin_unlock_irqrestore(&ch->rx_lock, flags);
+}
+
+static void scpi_handle_remote_msg(struct mbox_client *c, void *msg)
+{
+	struct scpi_chan *ch = container_of(c, struct scpi_chan, cl);
+	struct scpi_shared_mem __iomem *mem = ch->rx_payload;
+	u32 cmd = 0;
+
+	if (!scpi_info->is_legacy)
+		cmd = ioread32(&mem->command);
+
+	scpi_process_cmd(ch, cmd);
+}
+
+static void scpi_tx_prepare(struct mbox_client *c, void *msg)
+{
+	unsigned long flags;
+	struct scpi_xfer *t = msg;
+	struct scpi_chan *ch = container_of(c, struct scpi_chan, cl);
+	struct scpi_shared_mem __iomem *mem = ch->tx_payload;
+
+	if (t->tx_buf) {
+		if (scpi_info->is_legacy)
+			memcpy_toio(ch->tx_payload, t->tx_buf, t->tx_len);
+		else
+			memcpy_toio(mem->payload, t->tx_buf, t->tx_len);
+	}
+
+	if (t->rx_buf) {
+		if (!(++ch->token))
+			++ch->token;
+		t->cmd |= FIELD_PREP(CMD_TOKEN_ID_MASK, ch->token);
+		spin_lock_irqsave(&ch->rx_lock, flags);
+		list_add_tail(&t->node, &ch->rx_pending);
+		spin_unlock_irqrestore(&ch->rx_lock, flags);
+	}
+
+	if (!scpi_info->is_legacy)
+		iowrite32(t->cmd, &mem->command);
+}
+
+static struct scpi_xfer *get_scpi_xfer(struct scpi_chan *ch)
+{
+	struct scpi_xfer *t;
+
+	mutex_lock(&ch->xfers_lock);
+	if (list_empty(&ch->xfers_list)) {
+		mutex_unlock(&ch->xfers_lock);
+		return NULL;
+	}
+	t = list_first_entry(&ch->xfers_list, struct scpi_xfer, node);
+	list_del(&t->node);
+	mutex_unlock(&ch->xfers_lock);
+	return t;
+}
+
+static void put_scpi_xfer(struct scpi_xfer *t, struct scpi_chan *ch)
+{
+	mutex_lock(&ch->xfers_lock);
+	list_add_tail(&t->node, &ch->xfers_list);
+	mutex_unlock(&ch->xfers_lock);
+}
+
+static int scpi_send_message(u8 idx, void *tx_buf, unsigned int tx_len,
+			     void *rx_buf, unsigned int rx_len)
+{
+	int ret;
+	u8 chan;
+	u8 cmd;
+	struct scpi_xfer *msg;
+	struct scpi_chan *scpi_chan;
+
+	if (scpi_info->commands[idx] < 0)
+		return -EOPNOTSUPP;
+
+	cmd = scpi_info->commands[idx];
+
+	if (scpi_info->is_legacy)
+		chan = test_bit(cmd, scpi_info->cmd_priority) ? 1 : 0;
+	else
+		chan = atomic_inc_return(&scpi_info->next_chan) %
+			scpi_info->num_chans;
+	scpi_chan = scpi_info->channels + chan;
+
+	msg = get_scpi_xfer(scpi_chan);
+	if (!msg)
+		return -ENOMEM;
+
+	if (scpi_info->is_legacy) {
+		msg->cmd = PACK_LEGACY_SCPI_CMD(cmd, tx_len);
+		msg->slot = msg->cmd;
+	} else {
+		msg->slot = BIT(SCPI_SLOT);
+		msg->cmd = PACK_SCPI_CMD(cmd, tx_len);
+	}
+	msg->tx_buf = tx_buf;
+	msg->tx_len = tx_len;
+	msg->rx_buf = rx_buf;
+	msg->rx_len = rx_len;
+	reinit_completion(&msg->done);
+
+	ret = mbox_send_message(scpi_chan->chan, msg);
+	if (ret < 0 || !rx_buf)
+		goto out;
+
+	if (!wait_for_completion_timeout(&msg->done, MAX_RX_TIMEOUT))
+		ret = -ETIMEDOUT;
+	else
+		/* first status word */
+		ret = msg->status;
+out:
+	if (ret < 0 && rx_buf) /* remove entry from the list if timed-out */
+		scpi_process_cmd(scpi_chan, msg->cmd);
+
+	put_scpi_xfer(msg, scpi_chan);
+	/* SCPI error codes > 0, translate them to Linux scale*/
+	return ret > 0 ? scpi_to_linux_errno(ret) : ret;
+}
+
+static u32 scpi_get_version(void)
+{
+	return scpi_info->protocol_version;
+}
+
+static int
+scpi_clk_get_range(u16 clk_id, unsigned long *min, unsigned long *max)
+{
+	int ret;
+	struct clk_get_info clk;
+	__le16 le_clk_id = cpu_to_le16(clk_id);
+
+	ret = scpi_send_message(CMD_GET_CLOCK_INFO, &le_clk_id,
+				sizeof(le_clk_id), &clk, sizeof(clk));
+	if (!ret) {
+		*min = le32_to_cpu(clk.min_rate);
+		*max = le32_to_cpu(clk.max_rate);
+	}
+	return ret;
+}
+
+static unsigned long scpi_clk_get_val(u16 clk_id)
+{
+	int ret;
+	__le32 rate;
+	__le16 le_clk_id = cpu_to_le16(clk_id);
+
+	ret = scpi_send_message(CMD_GET_CLOCK_VALUE, &le_clk_id,
+				sizeof(le_clk_id), &rate, sizeof(rate));
+	if (ret)
+		return 0;
+
+	return le32_to_cpu(rate);
+}
+
+static int scpi_clk_set_val(u16 clk_id, unsigned long rate)
+{
+	int stat;
+	struct clk_set_value clk = {
+		.id = cpu_to_le16(clk_id),
+		.rate = cpu_to_le32(rate)
+	};
+
+	return scpi_send_message(CMD_SET_CLOCK_VALUE, &clk, sizeof(clk),
+				 &stat, sizeof(stat));
+}
+
+static int legacy_scpi_clk_set_val(u16 clk_id, unsigned long rate)
+{
+	int stat;
+	struct legacy_clk_set_value clk = {
+		.id = cpu_to_le16(clk_id),
+		.rate = cpu_to_le32(rate)
+	};
+
+	return scpi_send_message(CMD_SET_CLOCK_VALUE, &clk, sizeof(clk),
+				 &stat, sizeof(stat));
+}
+
+static int scpi_dvfs_get_idx(u8 domain)
+{
+	int ret;
+	u8 dvfs_idx;
+
+	ret = scpi_send_message(CMD_GET_DVFS, &domain, sizeof(domain),
+				&dvfs_idx, sizeof(dvfs_idx));
+
+	return ret ? ret : dvfs_idx;
+}
+
+static int scpi_dvfs_set_idx(u8 domain, u8 index)
+{
+	int stat;
+	struct dvfs_set dvfs = {domain, index};
+
+	return scpi_send_message(CMD_SET_DVFS, &dvfs, sizeof(dvfs),
+				 &stat, sizeof(stat));
+}
+
+static int opp_cmp_func(const void *opp1, const void *opp2)
+{
+	const struct scpi_opp *t1 = opp1, *t2 = opp2;
+
+	return t1->freq - t2->freq;
+}
+
+static struct scpi_dvfs_info *scpi_dvfs_get_info(u8 domain)
+{
+	struct scpi_dvfs_info *info;
+	struct scpi_opp *opp;
+	struct dvfs_info buf;
+	int ret, i;
+
+	if (domain >= MAX_DVFS_DOMAINS)
+		return ERR_PTR(-EINVAL);
+
+	if (scpi_info->dvfs[domain])	/* data already populated */
+		return scpi_info->dvfs[domain];
+
+	ret = scpi_send_message(CMD_GET_DVFS_INFO, &domain, sizeof(domain),
+				&buf, sizeof(buf));
+	if (ret)
+		return ERR_PTR(ret);
+
+	info = kmalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return ERR_PTR(-ENOMEM);
+
+	info->count = buf.opp_count;
+	info->latency = le16_to_cpu(buf.latency) * 1000; /* uS to nS */
+
+	info->opps = kcalloc(info->count, sizeof(*opp), GFP_KERNEL);
+	if (!info->opps) {
+		kfree(info);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	for (i = 0, opp = info->opps; i < info->count; i++, opp++) {
+		opp->freq = le32_to_cpu(buf.opps[i].freq);
+		opp->m_volt = le32_to_cpu(buf.opps[i].m_volt);
+	}
+
+	sort(info->opps, info->count, sizeof(*opp), opp_cmp_func, NULL);
+
+	scpi_info->dvfs[domain] = info;
+	return info;
+}
+
+static int scpi_dev_domain_id(struct device *dev)
+{
+	struct of_phandle_args clkspec;
+
+	if (of_parse_phandle_with_args(dev->of_node, "clocks", "#clock-cells",
+				       0, &clkspec))
+		return -EINVAL;
+
+	return clkspec.args[0];
+}
+
+static struct scpi_dvfs_info *scpi_dvfs_info(struct device *dev)
+{
+	int domain = scpi_dev_domain_id(dev);
+
+	if (domain < 0)
+		return ERR_PTR(domain);
+
+	return scpi_dvfs_get_info(domain);
+}
+
+static int scpi_dvfs_get_transition_latency(struct device *dev)
+{
+	struct scpi_dvfs_info *info = scpi_dvfs_info(dev);
+
+	if (IS_ERR(info))
+		return PTR_ERR(info);
+
+	return info->latency;
+}
+
+static int scpi_dvfs_add_opps_to_device(struct device *dev)
+{
+	int idx, ret;
+	struct scpi_opp *opp;
+	struct scpi_dvfs_info *info = scpi_dvfs_info(dev);
+
+	if (IS_ERR(info))
+		return PTR_ERR(info);
+
+	if (!info->opps)
+		return -EIO;
+
+	for (opp = info->opps, idx = 0; idx < info->count; idx++, opp++) {
+		ret = dev_pm_opp_add(dev, opp->freq, opp->m_volt * 1000);
+		if (ret) {
+			dev_warn(dev, "failed to add opp %uHz %umV\n",
+				 opp->freq, opp->m_volt);
+			while (idx-- > 0)
+				dev_pm_opp_remove(dev, (--opp)->freq);
+			return ret;
+		}
+	}
+	return 0;
+}
+
+static int scpi_sensor_get_capability(u16 *sensors)
+{
+	__le16 cap;
+	int ret;
+
+	ret = scpi_send_message(CMD_SENSOR_CAPABILITIES, NULL, 0, &cap,
+				sizeof(cap));
+	if (!ret)
+		*sensors = le16_to_cpu(cap);
+
+	return ret;
+}
+
+static int scpi_sensor_get_info(u16 sensor_id, struct scpi_sensor_info *info)
+{
+	__le16 id = cpu_to_le16(sensor_id);
+	struct _scpi_sensor_info _info;
+	int ret;
+
+	ret = scpi_send_message(CMD_SENSOR_INFO, &id, sizeof(id),
+				&_info, sizeof(_info));
+	if (!ret) {
+		memcpy(info, &_info, sizeof(*info));
+		info->sensor_id = le16_to_cpu(_info.sensor_id);
+	}
+
+	return ret;
+}
+
+static int scpi_sensor_get_value(u16 sensor, u64 *val)
+{
+	__le16 id = cpu_to_le16(sensor);
+	__le64 value;
+	int ret;
+
+	ret = scpi_send_message(CMD_SENSOR_VALUE, &id, sizeof(id),
+				&value, sizeof(value));
+	if (ret)
+		return ret;
+
+	if (scpi_info->is_legacy)
+		/* only 32-bits supported, upper 32 bits can be junk */
+		*val = le32_to_cpup((__le32 *)&value);
+	else
+		*val = le64_to_cpu(value);
+
+	return 0;
+}
+
+static int scpi_device_get_power_state(u16 dev_id)
+{
+	int ret;
+	u8 pstate;
+	__le16 id = cpu_to_le16(dev_id);
+
+	ret = scpi_send_message(CMD_GET_DEVICE_PWR_STATE, &id,
+				sizeof(id), &pstate, sizeof(pstate));
+	return ret ? ret : pstate;
+}
+
+static int scpi_device_set_power_state(u16 dev_id, u8 pstate)
+{
+	int stat;
+	struct dev_pstate_set dev_set = {
+		.dev_id = cpu_to_le16(dev_id),
+		.pstate = pstate,
+	};
+
+	return scpi_send_message(CMD_SET_DEVICE_PWR_STATE, &dev_set,
+				 sizeof(dev_set), &stat, sizeof(stat));
+}
+
+static struct scpi_ops scpi_ops = {
+	.get_version = scpi_get_version,
+	.clk_get_range = scpi_clk_get_range,
+	.clk_get_val = scpi_clk_get_val,
+	.clk_set_val = scpi_clk_set_val,
+	.dvfs_get_idx = scpi_dvfs_get_idx,
+	.dvfs_set_idx = scpi_dvfs_set_idx,
+	.dvfs_get_info = scpi_dvfs_get_info,
+	.device_domain_id = scpi_dev_domain_id,
+	.get_transition_latency = scpi_dvfs_get_transition_latency,
+	.add_opps_to_device = scpi_dvfs_add_opps_to_device,
+	.sensor_get_capability = scpi_sensor_get_capability,
+	.sensor_get_info = scpi_sensor_get_info,
+	.sensor_get_value = scpi_sensor_get_value,
+	.device_get_power_state = scpi_device_get_power_state,
+	.device_set_power_state = scpi_device_set_power_state,
+};
+
+struct scpi_ops *get_scpi_ops(void)
+{
+	return scpi_info ? scpi_info->scpi_ops : NULL;
+}
+EXPORT_SYMBOL_GPL(get_scpi_ops);
+
+static int scpi_init_versions(struct scpi_drvinfo *info)
+{
+	int ret;
+	struct scp_capabilities caps;
+
+	ret = scpi_send_message(CMD_SCPI_CAPABILITIES, NULL, 0,
+				&caps, sizeof(caps));
+	if (!ret) {
+		info->protocol_version = le32_to_cpu(caps.protocol_version);
+		info->firmware_version = le32_to_cpu(caps.platform_version);
+	}
+	/* Ignore error if not implemented */
+	if (info->is_legacy && ret == -EOPNOTSUPP)
+		return 0;
+
+	return ret;
+}
+
+static ssize_t protocol_version_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct scpi_drvinfo *scpi_info = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%lu.%lu\n",
+		FIELD_GET(PROTO_REV_MAJOR_MASK, scpi_info->protocol_version),
+		FIELD_GET(PROTO_REV_MINOR_MASK, scpi_info->protocol_version));
+}
+static DEVICE_ATTR_RO(protocol_version);
+
+static ssize_t firmware_version_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct scpi_drvinfo *scpi_info = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%lu.%lu.%lu\n",
+		FIELD_GET(FW_REV_MAJOR_MASK, scpi_info->firmware_version),
+		FIELD_GET(FW_REV_MINOR_MASK, scpi_info->firmware_version),
+		FIELD_GET(FW_REV_PATCH_MASK, scpi_info->firmware_version));
+}
+static DEVICE_ATTR_RO(firmware_version);
+
+static struct attribute *versions_attrs[] = {
+	&dev_attr_firmware_version.attr,
+	&dev_attr_protocol_version.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(versions);
+
+static void scpi_free_channels(void *data)
+{
+	struct scpi_drvinfo *info = data;
+	int i;
+
+	for (i = 0; i < info->num_chans; i++)
+		mbox_free_channel(info->channels[i].chan);
+}
+
+static int scpi_remove(struct platform_device *pdev)
+{
+	int i;
+	struct scpi_drvinfo *info = platform_get_drvdata(pdev);
+
+	scpi_info = NULL; /* stop exporting SCPI ops through get_scpi_ops */
+
+	for (i = 0; i < MAX_DVFS_DOMAINS && info->dvfs[i]; i++) {
+		kfree(info->dvfs[i]->opps);
+		kfree(info->dvfs[i]);
+	}
+
+	return 0;
+}
+
+#define MAX_SCPI_XFERS		10
+static int scpi_alloc_xfer_list(struct device *dev, struct scpi_chan *ch)
+{
+	int i;
+	struct scpi_xfer *xfers;
+
+	xfers = devm_kcalloc(dev, MAX_SCPI_XFERS, sizeof(*xfers), GFP_KERNEL);
+	if (!xfers)
+		return -ENOMEM;
+
+	ch->xfers = xfers;
+	for (i = 0; i < MAX_SCPI_XFERS; i++, xfers++) {
+		init_completion(&xfers->done);
+		list_add_tail(&xfers->node, &ch->xfers_list);
+	}
+
+	return 0;
+}
+
+static const struct of_device_id legacy_scpi_of_match[] = {
+	{.compatible = "arm,scpi-pre-1.0"},
+	{},
+};
+
+static const struct of_device_id shmem_of_match[] __maybe_unused = {
+	{ .compatible = "amlogic,meson-gxbb-scp-shmem", },
+	{ .compatible = "amlogic,meson-axg-scp-shmem", },
+	{ .compatible = "arm,juno-scp-shmem", },
+	{ .compatible = "arm,scp-shmem", },
+	{ }
+};
+
+static int scpi_probe(struct platform_device *pdev)
+{
+	int count, idx, ret;
+	struct resource res;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct scpi_drvinfo *scpi_drvinfo;
+
+	scpi_drvinfo = devm_kzalloc(dev, sizeof(*scpi_drvinfo), GFP_KERNEL);
+	if (!scpi_drvinfo)
+		return -ENOMEM;
+
+	if (of_match_device(legacy_scpi_of_match, &pdev->dev))
+		scpi_drvinfo->is_legacy = true;
+
+	count = of_count_phandle_with_args(np, "mboxes", "#mbox-cells");
+	if (count < 0) {
+		dev_err(dev, "no mboxes property in '%pOF'\n", np);
+		return -ENODEV;
+	}
+
+	scpi_drvinfo->channels =
+		devm_kcalloc(dev, count, sizeof(struct scpi_chan), GFP_KERNEL);
+	if (!scpi_drvinfo->channels)
+		return -ENOMEM;
+
+	ret = devm_add_action(dev, scpi_free_channels, scpi_drvinfo);
+	if (ret)
+		return ret;
+
+	for (; scpi_drvinfo->num_chans < count; scpi_drvinfo->num_chans++) {
+		resource_size_t size;
+		int idx = scpi_drvinfo->num_chans;
+		struct scpi_chan *pchan = scpi_drvinfo->channels + idx;
+		struct mbox_client *cl = &pchan->cl;
+		struct device_node *shmem = of_parse_phandle(np, "shmem", idx);
+
+		if (!of_match_node(shmem_of_match, shmem))
+			return -ENXIO;
+
+		ret = of_address_to_resource(shmem, 0, &res);
+		of_node_put(shmem);
+		if (ret) {
+			dev_err(dev, "failed to get SCPI payload mem resource\n");
+			return ret;
+		}
+
+		size = resource_size(&res);
+		pchan->rx_payload = devm_ioremap(dev, res.start, size);
+		if (!pchan->rx_payload) {
+			dev_err(dev, "failed to ioremap SCPI payload\n");
+			return -EADDRNOTAVAIL;
+		}
+		pchan->tx_payload = pchan->rx_payload + (size >> 1);
+
+		cl->dev = dev;
+		cl->rx_callback = scpi_handle_remote_msg;
+		cl->tx_prepare = scpi_tx_prepare;
+		cl->tx_block = true;
+		cl->tx_tout = 20;
+		cl->knows_txdone = false; /* controller can't ack */
+
+		INIT_LIST_HEAD(&pchan->rx_pending);
+		INIT_LIST_HEAD(&pchan->xfers_list);
+		spin_lock_init(&pchan->rx_lock);
+		mutex_init(&pchan->xfers_lock);
+
+		ret = scpi_alloc_xfer_list(dev, pchan);
+		if (!ret) {
+			pchan->chan = mbox_request_channel(cl, idx);
+			if (!IS_ERR(pchan->chan))
+				continue;
+			ret = PTR_ERR(pchan->chan);
+			if (ret != -EPROBE_DEFER)
+				dev_err(dev, "failed to get channel%d err %d\n",
+					idx, ret);
+		}
+		return ret;
+	}
+
+	scpi_drvinfo->commands = scpi_std_commands;
+
+	platform_set_drvdata(pdev, scpi_drvinfo);
+
+	if (scpi_drvinfo->is_legacy) {
+		/* Replace with legacy variants */
+		scpi_ops.clk_set_val = legacy_scpi_clk_set_val;
+		scpi_drvinfo->commands = scpi_legacy_commands;
+
+		/* Fill priority bitmap */
+		for (idx = 0; idx < ARRAY_SIZE(legacy_hpriority_cmds); idx++)
+			set_bit(legacy_hpriority_cmds[idx],
+				scpi_drvinfo->cmd_priority);
+	}
+
+	scpi_info = scpi_drvinfo;
+
+	ret = scpi_init_versions(scpi_drvinfo);
+	if (ret) {
+		dev_err(dev, "incorrect or no SCP firmware found\n");
+		scpi_info = NULL;
+		return ret;
+	}
+
+	if (scpi_drvinfo->is_legacy && !scpi_drvinfo->protocol_version &&
+	    !scpi_drvinfo->firmware_version)
+		dev_info(dev, "SCP Protocol legacy pre-1.0 firmware\n");
+	else
+		dev_info(dev, "SCP Protocol %lu.%lu Firmware %lu.%lu.%lu version\n",
+			 FIELD_GET(PROTO_REV_MAJOR_MASK,
+				   scpi_drvinfo->protocol_version),
+			 FIELD_GET(PROTO_REV_MINOR_MASK,
+				   scpi_drvinfo->protocol_version),
+			 FIELD_GET(FW_REV_MAJOR_MASK,
+				   scpi_drvinfo->firmware_version),
+			 FIELD_GET(FW_REV_MINOR_MASK,
+				   scpi_drvinfo->firmware_version),
+			 FIELD_GET(FW_REV_PATCH_MASK,
+				   scpi_drvinfo->firmware_version));
+
+	scpi_drvinfo->scpi_ops = &scpi_ops;
+
+	ret = devm_of_platform_populate(dev);
+	if (ret)
+		scpi_info = NULL;
+
+	return ret;
+}
+
+static const struct of_device_id scpi_of_match[] = {
+	{.compatible = "arm,scpi"},
+	{.compatible = "arm,scpi-pre-1.0"},
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, scpi_of_match);
+
+static struct platform_driver scpi_driver = {
+	.driver = {
+		.name = "scpi_protocol",
+		.of_match_table = scpi_of_match,
+		.dev_groups = versions_groups,
+	},
+	.probe = scpi_probe,
+	.remove = scpi_remove,
+};
+module_platform_driver(scpi_driver);
+
+MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
+MODULE_DESCRIPTION("ARM SCPI mailbox protocol driver");
+MODULE_LICENSE("GPL v2");