drivers/firmware/imx/imx-scu.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright 2018 NXP
  *  Author: Dong Aisheng <aisheng.dong@nxp.com>
  *
  * Implementation of the SCU IPC functions using MUs (client side).
  *
  */

 #include <linux/err.h>
 #include <linux/firmware/imx/ipc.h>
 #include <linux/firmware/imx/sci.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/kernel.h>
 #include <linux/mailbox_client.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>

 #define SCU_MU_CHAN_NUM		8
 #define MAX_RX_TIMEOUT		(msecs_to_jiffies(3000))

 struct imx_sc_chan {
 	struct imx_sc_ipc *sc_ipc;

 	struct mbox_client cl;
 	struct mbox_chan *ch;
 	int idx;
 	struct completion tx_done;
 };

 struct imx_sc_ipc {
 	/* SCU uses 4 Tx and 4 Rx channels */
 	struct imx_sc_chan chans[SCU_MU_CHAN_NUM];
 	struct device *dev;
 	struct mutex lock;
 	struct completion done;
 	bool fast_ipc;

 	/* temporarily store the SCU msg */
 	u32 *msg;
 	u8 rx_size;
 	u8 count;
 };

 /*
  * This type is used to indicate error response for most functions.
  */
 enum imx_sc_error_codes {
 	IMX_SC_ERR_NONE = 0,	/* Success */
 	IMX_SC_ERR_VERSION = 1,	/* Incompatible API version */
 	IMX_SC_ERR_CONFIG = 2,	/* Configuration error */
 	IMX_SC_ERR_PARM = 3,	/* Bad parameter */
 	IMX_SC_ERR_NOACCESS = 4,	/* Permission error (no access) */
 	IMX_SC_ERR_LOCKED = 5,	/* Permission error (locked) */
 	IMX_SC_ERR_UNAVAILABLE = 6,	/* Unavailable (out of resources) */
 	IMX_SC_ERR_NOTFOUND = 7,	/* Not found */
 	IMX_SC_ERR_NOPOWER = 8,	/* No power */
 	IMX_SC_ERR_IPC = 9,		/* Generic IPC error */
 	IMX_SC_ERR_BUSY = 10,	/* Resource is currently busy/active */
 	IMX_SC_ERR_FAIL = 11,	/* General I/O failure */
 	IMX_SC_ERR_LAST
 };

 static int imx_sc_linux_errmap[IMX_SC_ERR_LAST] = {
 	0,	 /* IMX_SC_ERR_NONE */
 	-EINVAL, /* IMX_SC_ERR_VERSION */
 	-EINVAL, /* IMX_SC_ERR_CONFIG */
 	-EINVAL, /* IMX_SC_ERR_PARM */
 	-EACCES, /* IMX_SC_ERR_NOACCESS */
 	-EACCES, /* IMX_SC_ERR_LOCKED */
 	-ERANGE, /* IMX_SC_ERR_UNAVAILABLE */
 	-EEXIST, /* IMX_SC_ERR_NOTFOUND */
 	-EPERM,	 /* IMX_SC_ERR_NOPOWER */
 	-EPIPE,	 /* IMX_SC_ERR_IPC */
 	-EBUSY,	 /* IMX_SC_ERR_BUSY */
 	-EIO,	 /* IMX_SC_ERR_FAIL */
 };

 static struct imx_sc_ipc *imx_sc_ipc_handle;

 static inline int imx_sc_to_linux_errno(int errno)
 {
 	if (errno >= IMX_SC_ERR_NONE && errno < IMX_SC_ERR_LAST)
 		return imx_sc_linux_errmap[errno];
 	return -EIO;
 }

 /*
  * Get the default handle used by SCU
  */
 int imx_scu_get_handle(struct imx_sc_ipc **ipc)
 {
 	if (!imx_sc_ipc_handle)
 		return -EPROBE_DEFER;

 	*ipc = imx_sc_ipc_handle;
 	return 0;
 }
 EXPORT_SYMBOL(imx_scu_get_handle);

 /* Callback called when the word of a message is ack-ed, eg read by SCU */
 static void imx_scu_tx_done(struct mbox_client *cl, void *mssg, int r)
 {
 	struct imx_sc_chan *sc_chan = container_of(cl, struct imx_sc_chan, cl);

 	complete(&sc_chan->tx_done);
 }

 static void imx_scu_rx_callback(struct mbox_client *c, void *msg)
 {
 	struct imx_sc_chan *sc_chan = container_of(c, struct imx_sc_chan, cl);
 	struct imx_sc_ipc *sc_ipc = sc_chan->sc_ipc;
 	struct imx_sc_rpc_msg *hdr;
 	u32 *data = msg;
 	int i;

 	if (!sc_ipc->msg) {
 		dev_warn(sc_ipc->dev, "unexpected rx idx %d 0x%08x, ignore!\n",
 				sc_chan->idx, *data);
 		return;
 	}

 	if (sc_ipc->fast_ipc) {
 		hdr = msg;
 		sc_ipc->rx_size = hdr->size;
 		sc_ipc->msg[0] = *data++;

 		for (i = 1; i < sc_ipc->rx_size; i++)
 			sc_ipc->msg[i] = *data++;

 		complete(&sc_ipc->done);

 		return;
 	}

 	if (sc_chan->idx == 0) {
 		hdr = msg;
 		sc_ipc->rx_size = hdr->size;
 		dev_dbg(sc_ipc->dev, "msg rx size %u\n", sc_ipc->rx_size);
 		if (sc_ipc->rx_size > 4)
 			dev_warn(sc_ipc->dev, "RPC does not support receiving over 4 words: %u\n",
 				 sc_ipc->rx_size);
 	}

 	sc_ipc->msg[sc_chan->idx] = *data;
 	sc_ipc->count++;

 	dev_dbg(sc_ipc->dev, "mu %u msg %u 0x%x\n", sc_chan->idx,
 		sc_ipc->count, *data);

 	if ((sc_ipc->rx_size != 0) && (sc_ipc->count == sc_ipc->rx_size))
 		complete(&sc_ipc->done);
 }

 static int imx_scu_ipc_write(struct imx_sc_ipc *sc_ipc, void *msg)
 {
 	struct imx_sc_rpc_msg hdr = *(struct imx_sc_rpc_msg *)msg;
 	struct imx_sc_chan *sc_chan;
 	u32 *data = msg;
 	int ret;
 	int size;
 	int i;

 	/* Check size */
 	if (hdr.size > IMX_SC_RPC_MAX_MSG)
 		return -EINVAL;

 	dev_dbg(sc_ipc->dev, "RPC SVC %u FUNC %u SIZE %u\n", hdr.svc,
 		hdr.func, hdr.size);

 	size = sc_ipc->fast_ipc ? 1 : hdr.size;
 	for (i = 0; i < size; i++) {
 		sc_chan = &sc_ipc->chans[i % 4];

 		/*
 		 * SCU requires that all messages words are written
 		 * sequentially but linux MU driver implements multiple
 		 * independent channels for each register so ordering between
 		 * different channels must be ensured by SCU API interface.
 		 *
 		 * Wait for tx_done before every send to ensure that no
 		 * queueing happens at the mailbox channel level.
 		 */
 		if (!sc_ipc->fast_ipc) {
 			wait_for_completion(&sc_chan->tx_done);
 			reinit_completion(&sc_chan->tx_done);
 		}

 		ret = mbox_send_message(sc_chan->ch, &data[i]);
 		if (ret < 0)
 			return ret;
 	}

 	return 0;
 }

 /*
  * RPC command/response
  */
 int imx_scu_call_rpc(struct imx_sc_ipc *sc_ipc, void *msg, bool have_resp)
 {
 	uint8_t saved_svc, saved_func;
 	struct imx_sc_rpc_msg *hdr;
 	int ret;

 	if (WARN_ON(!sc_ipc || !msg))
 		return -EINVAL;

 	mutex_lock(&sc_ipc->lock);
 	reinit_completion(&sc_ipc->done);

 	if (have_resp) {
 		sc_ipc->msg = msg;
 		saved_svc = ((struct imx_sc_rpc_msg *)msg)->svc;
 		saved_func = ((struct imx_sc_rpc_msg *)msg)->func;
 	}
 	sc_ipc->count = 0;
 	ret = imx_scu_ipc_write(sc_ipc, msg);
 	if (ret < 0) {
 		dev_err(sc_ipc->dev, "RPC send msg failed: %d\n", ret);
 		goto out;
 	}

 	if (have_resp) {
 		if (!wait_for_completion_timeout(&sc_ipc->done,
 						 MAX_RX_TIMEOUT)) {
 			dev_err(sc_ipc->dev, "RPC send msg timeout\n");
 			mutex_unlock(&sc_ipc->lock);
 			return -ETIMEDOUT;
 		}

 		/* response status is stored in hdr->func field */
 		hdr = msg;
 		ret = hdr->func;
 		/*
 		 * Some special SCU firmware APIs do NOT have return value
 		 * in hdr->func, but they do have response data, those special
 		 * APIs are defined as void function in SCU firmware, so they
 		 * should be treated as return success always.
 		 */
 		if ((saved_svc == IMX_SC_RPC_SVC_MISC) &&
 			(saved_func == IMX_SC_MISC_FUNC_UNIQUE_ID ||
 			 saved_func == IMX_SC_MISC_FUNC_GET_BUTTON_STATUS))
 			ret = 0;
 	}

 out:
 	sc_ipc->msg = NULL;
 	mutex_unlock(&sc_ipc->lock);

 	dev_dbg(sc_ipc->dev, "RPC SVC done\n");

 	return imx_sc_to_linux_errno(ret);
 }
 EXPORT_SYMBOL(imx_scu_call_rpc);

 static int imx_scu_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct imx_sc_ipc *sc_ipc;
 	struct imx_sc_chan *sc_chan;
 	struct mbox_client *cl;
 	char *chan_name;
 	struct of_phandle_args args;
 	int num_channel;
 	int ret;
 	int i;

 	sc_ipc = devm_kzalloc(dev, sizeof(*sc_ipc), GFP_KERNEL);
 	if (!sc_ipc)
 		return -ENOMEM;

 	ret = of_parse_phandle_with_args(pdev->dev.of_node, "mboxes",
 					 "#mbox-cells", 0, &args);
 	if (ret)
 		return ret;

 	sc_ipc->fast_ipc = of_device_is_compatible(args.np, "fsl,imx8-mu-scu");

 	num_channel = sc_ipc->fast_ipc ? 2 : SCU_MU_CHAN_NUM;
 	for (i = 0; i < num_channel; i++) {
 		if (i < num_channel / 2)
 			chan_name = kasprintf(GFP_KERNEL, "tx%d", i);
 		else
 			chan_name = kasprintf(GFP_KERNEL, "rx%d",
 					      i - num_channel / 2);

 		if (!chan_name)
 			return -ENOMEM;

 		sc_chan = &sc_ipc->chans[i];
 		cl = &sc_chan->cl;
 		cl->dev = dev;
 		cl->tx_block = false;
 		cl->knows_txdone = true;
 		cl->rx_callback = imx_scu_rx_callback;

 		if (!sc_ipc->fast_ipc) {
 			/* Initial tx_done completion as "done" */
 			cl->tx_done = imx_scu_tx_done;
 			init_completion(&sc_chan->tx_done);
 			complete(&sc_chan->tx_done);
 		}

 		sc_chan->sc_ipc = sc_ipc;
 		sc_chan->idx = i % (num_channel / 2);
 		sc_chan->ch = mbox_request_channel_byname(cl, chan_name);
 		if (IS_ERR(sc_chan->ch)) {
 			ret = PTR_ERR(sc_chan->ch);
 			dev_err_probe(dev, ret, "Failed to request mbox chan %s\n",
 				      chan_name);
 			kfree(chan_name);
 			return ret;
 		}

 		dev_dbg(dev, "request mbox chan %s\n", chan_name);
 		/* chan_name is not used anymore by framework */
 		kfree(chan_name);
 	}

 	sc_ipc->dev = dev;
 	mutex_init(&sc_ipc->lock);
 	init_completion(&sc_ipc->done);

 	imx_sc_ipc_handle = sc_ipc;

 	ret = imx_scu_soc_init(dev);
 	if (ret)
 		dev_warn(dev, "failed to initialize SoC info: %d\n", ret);

 	ret = imx_scu_enable_general_irq_channel(dev);
 	if (ret)
 		dev_warn(dev,
 			"failed to enable general irq channel: %d\n", ret);

 	dev_info(dev, "NXP i.MX SCU Initialized\n");

 	return devm_of_platform_populate(dev);
 }

 static const struct of_device_id imx_scu_match[] = {
 	{ .compatible = "fsl,imx-scu", },
 	{ /* Sentinel */ }
 };

 static struct platform_driver imx_scu_driver = {
 	.driver = {
 		.name = "imx-scu",
 		.of_match_table = imx_scu_match,
 	},
 	.probe = imx_scu_probe,
 };

 static int __init imx_scu_driver_init(void)
 {
 	return platform_driver_register(&imx_scu_driver);
 }
 subsys_initcall_sync(imx_scu_driver_init);

 MODULE_AUTHOR("Dong Aisheng <aisheng.dong@nxp.com>");
 MODULE_DESCRIPTION("IMX SCU firmware protocol driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright 2018 NXP
	* Author: Dong Aisheng <aisheng.dong@nxp.com>
	*
	* Implementation of the SCU IPC functions using MUs (client side).
	*
	*/

	#include <linux/err.h>
	#include <linux/firmware/imx/ipc.h>
	#include <linux/firmware/imx/sci.h>
	#include <linux/interrupt.h>
	#include <linux/irq.h>
	#include <linux/kernel.h>
	#include <linux/mailbox_client.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/of.h>
	#include <linux/of_platform.h>
	#include <linux/platform_device.h>

	#define SCU_MU_CHAN_NUM 8
	#define MAX_RX_TIMEOUT (msecs_to_jiffies(3000))

	struct imx_sc_chan {
	struct imx_sc_ipc *sc_ipc;

	struct mbox_client cl;
	struct mbox_chan *ch;
	int idx;
	struct completion tx_done;
	};

	struct imx_sc_ipc {
	/* SCU uses 4 Tx and 4 Rx channels */
	struct imx_sc_chan chans[SCU_MU_CHAN_NUM];
	struct device *dev;
	struct mutex lock;
	struct completion done;
	bool fast_ipc;

	/* temporarily store the SCU msg */
	u32 *msg;
	u8 rx_size;
	u8 count;
	};

	/*
	* This type is used to indicate error response for most functions.
	*/
	enum imx_sc_error_codes {
	IMX_SC_ERR_NONE = 0, /* Success */
	IMX_SC_ERR_VERSION = 1, /* Incompatible API version */
	IMX_SC_ERR_CONFIG = 2, /* Configuration error */
	IMX_SC_ERR_PARM = 3, /* Bad parameter */
	IMX_SC_ERR_NOACCESS = 4, /* Permission error (no access) */
	IMX_SC_ERR_LOCKED = 5, /* Permission error (locked) */
	IMX_SC_ERR_UNAVAILABLE = 6, /* Unavailable (out of resources) */
	IMX_SC_ERR_NOTFOUND = 7, /* Not found */
	IMX_SC_ERR_NOPOWER = 8, /* No power */
	IMX_SC_ERR_IPC = 9, /* Generic IPC error */
	IMX_SC_ERR_BUSY = 10, /* Resource is currently busy/active */
	IMX_SC_ERR_FAIL = 11, /* General I/O failure */
	IMX_SC_ERR_LAST
	};

	static int imx_sc_linux_errmap[IMX_SC_ERR_LAST] = {
	0, /* IMX_SC_ERR_NONE */
	-EINVAL, /* IMX_SC_ERR_VERSION */
	-EINVAL, /* IMX_SC_ERR_CONFIG */
	-EINVAL, /* IMX_SC_ERR_PARM */
	-EACCES, /* IMX_SC_ERR_NOACCESS */
	-EACCES, /* IMX_SC_ERR_LOCKED */
	-ERANGE, /* IMX_SC_ERR_UNAVAILABLE */
	-EEXIST, /* IMX_SC_ERR_NOTFOUND */
	-EPERM, /* IMX_SC_ERR_NOPOWER */
	-EPIPE, /* IMX_SC_ERR_IPC */
	-EBUSY, /* IMX_SC_ERR_BUSY */
	-EIO, /* IMX_SC_ERR_FAIL */
	};

	static struct imx_sc_ipc *imx_sc_ipc_handle;

	static inline int imx_sc_to_linux_errno(int errno)
	{
	if (errno >= IMX_SC_ERR_NONE && errno < IMX_SC_ERR_LAST)
	return imx_sc_linux_errmap[errno];
	return -EIO;
	}

	/*
	* Get the default handle used by SCU
	*/
	int imx_scu_get_handle(struct imx_sc_ipc **ipc)
	{
	if (!imx_sc_ipc_handle)
	return -EPROBE_DEFER;

	*ipc = imx_sc_ipc_handle;
	return 0;
	}
	EXPORT_SYMBOL(imx_scu_get_handle);

	/* Callback called when the word of a message is ack-ed, eg read by SCU */
	static void imx_scu_tx_done(struct mbox_client cl, void mssg, int r)
	{
	struct imx_sc_chan *sc_chan = container_of(cl, struct imx_sc_chan, cl);

	complete(&sc_chan->tx_done);
	}

	static void imx_scu_rx_callback(struct mbox_client c, void msg)
	{
	struct imx_sc_chan *sc_chan = container_of(c, struct imx_sc_chan, cl);
	struct imx_sc_ipc *sc_ipc = sc_chan->sc_ipc;
	struct imx_sc_rpc_msg *hdr;
	u32 *data = msg;
	int i;

	if (!sc_ipc->msg) {
	dev_warn(sc_ipc->dev, "unexpected rx idx %d 0x%08x, ignore!\n",
	sc_chan->idx, *data);
	return;
	}

	if (sc_ipc->fast_ipc) {
	hdr = msg;
	sc_ipc->rx_size = hdr->size;
	sc_ipc->msg[0] = *data++;

	for (i = 1; i < sc_ipc->rx_size; i++)
	sc_ipc->msg[i] = *data++;

	complete(&sc_ipc->done);

	return;
	}

	if (sc_chan->idx == 0) {
	hdr = msg;
	sc_ipc->rx_size = hdr->size;
	dev_dbg(sc_ipc->dev, "msg rx size %u\n", sc_ipc->rx_size);
	if (sc_ipc->rx_size > 4)
	dev_warn(sc_ipc->dev, "RPC does not support receiving over 4 words: %u\n",
	sc_ipc->rx_size);
	}

	sc_ipc->msg[sc_chan->idx] = *data;
	sc_ipc->count++;

	dev_dbg(sc_ipc->dev, "mu %u msg %u 0x%x\n", sc_chan->idx,
	sc_ipc->count, *data);

	if ((sc_ipc->rx_size != 0) && (sc_ipc->count == sc_ipc->rx_size))
	complete(&sc_ipc->done);
	}

	static int imx_scu_ipc_write(struct imx_sc_ipc sc_ipc, void msg)
	{
	struct imx_sc_rpc_msg hdr = (struct imx_sc_rpc_msg )msg;
	struct imx_sc_chan *sc_chan;
	u32 *data = msg;
	int ret;
	int size;
	int i;

	/* Check size */
	if (hdr.size > IMX_SC_RPC_MAX_MSG)
	return -EINVAL;

	dev_dbg(sc_ipc->dev, "RPC SVC %u FUNC %u SIZE %u\n", hdr.svc,
	hdr.func, hdr.size);

	size = sc_ipc->fast_ipc ? 1 : hdr.size;
	for (i = 0; i < size; i++) {
	sc_chan = &sc_ipc->chans[i % 4];

	/*
	* SCU requires that all messages words are written
	* sequentially but linux MU driver implements multiple
	* independent channels for each register so ordering between
	* different channels must be ensured by SCU API interface.
	*
	* Wait for tx_done before every send to ensure that no
	* queueing happens at the mailbox channel level.
	*/
	if (!sc_ipc->fast_ipc) {
	wait_for_completion(&sc_chan->tx_done);
	reinit_completion(&sc_chan->tx_done);
	}

	ret = mbox_send_message(sc_chan->ch, &data[i]);
	if (ret < 0)
	return ret;
	}

	return 0;
	}

	/*
	* RPC command/response
	*/
	int imx_scu_call_rpc(struct imx_sc_ipc sc_ipc, void msg, bool have_resp)
	{
	uint8_t saved_svc, saved_func;
	struct imx_sc_rpc_msg *hdr;
	int ret;

	if (WARN_ON(!sc_ipc \|\| !msg))
	return -EINVAL;

	mutex_lock(&sc_ipc->lock);
	reinit_completion(&sc_ipc->done);

	if (have_resp) {
	sc_ipc->msg = msg;
	saved_svc = ((struct imx_sc_rpc_msg *)msg)->svc;
	saved_func = ((struct imx_sc_rpc_msg *)msg)->func;
	}
	sc_ipc->count = 0;
	ret = imx_scu_ipc_write(sc_ipc, msg);
	if (ret < 0) {
	dev_err(sc_ipc->dev, "RPC send msg failed: %d\n", ret);
	goto out;
	}

	if (have_resp) {
	if (!wait_for_completion_timeout(&sc_ipc->done,
	MAX_RX_TIMEOUT)) {
	dev_err(sc_ipc->dev, "RPC send msg timeout\n");
	mutex_unlock(&sc_ipc->lock);
	return -ETIMEDOUT;
	}

	/* response status is stored in hdr->func field */
	hdr = msg;
	ret = hdr->func;
	/*
	* Some special SCU firmware APIs do NOT have return value
	* in hdr->func, but they do have response data, those special
	* APIs are defined as void function in SCU firmware, so they
	* should be treated as return success always.
	*/
	if ((saved_svc == IMX_SC_RPC_SVC_MISC) &&
	(saved_func == IMX_SC_MISC_FUNC_UNIQUE_ID \|\|
	saved_func == IMX_SC_MISC_FUNC_GET_BUTTON_STATUS))
	ret = 0;
	}

	out:
	sc_ipc->msg = NULL;
	mutex_unlock(&sc_ipc->lock);

	dev_dbg(sc_ipc->dev, "RPC SVC done\n");

	return imx_sc_to_linux_errno(ret);
	}
	EXPORT_SYMBOL(imx_scu_call_rpc);

	static int imx_scu_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct imx_sc_ipc *sc_ipc;
	struct imx_sc_chan *sc_chan;
	struct mbox_client *cl;
	char *chan_name;
	struct of_phandle_args args;
	int num_channel;
	int ret;
	int i;

	sc_ipc = devm_kzalloc(dev, sizeof(*sc_ipc), GFP_KERNEL);
	if (!sc_ipc)
	return -ENOMEM;

	ret = of_parse_phandle_with_args(pdev->dev.of_node, "mboxes",
	"#mbox-cells", 0, &args);
	if (ret)
	return ret;

	sc_ipc->fast_ipc = of_device_is_compatible(args.np, "fsl,imx8-mu-scu");

	num_channel = sc_ipc->fast_ipc ? 2 : SCU_MU_CHAN_NUM;
	for (i = 0; i < num_channel; i++) {
	if (i < num_channel / 2)
	chan_name = kasprintf(GFP_KERNEL, "tx%d", i);
	else
	chan_name = kasprintf(GFP_KERNEL, "rx%d",
	i - num_channel / 2);

	if (!chan_name)
	return -ENOMEM;

	sc_chan = &sc_ipc->chans[i];
	cl = &sc_chan->cl;
	cl->dev = dev;
	cl->tx_block = false;
	cl->knows_txdone = true;
	cl->rx_callback = imx_scu_rx_callback;

	if (!sc_ipc->fast_ipc) {
	/* Initial tx_done completion as "done" */
	cl->tx_done = imx_scu_tx_done;
	init_completion(&sc_chan->tx_done);
	complete(&sc_chan->tx_done);
	}

	sc_chan->sc_ipc = sc_ipc;
	sc_chan->idx = i % (num_channel / 2);
	sc_chan->ch = mbox_request_channel_byname(cl, chan_name);
	if (IS_ERR(sc_chan->ch)) {
	ret = PTR_ERR(sc_chan->ch);
	dev_err_probe(dev, ret, "Failed to request mbox chan %s\n",
	chan_name);
	kfree(chan_name);
	return ret;
	}

	dev_dbg(dev, "request mbox chan %s\n", chan_name);
	/* chan_name is not used anymore by framework */
	kfree(chan_name);
	}

	sc_ipc->dev = dev;
	mutex_init(&sc_ipc->lock);
	init_completion(&sc_ipc->done);

	imx_sc_ipc_handle = sc_ipc;

	ret = imx_scu_soc_init(dev);
	if (ret)
	dev_warn(dev, "failed to initialize SoC info: %d\n", ret);

	ret = imx_scu_enable_general_irq_channel(dev);
	if (ret)
	dev_warn(dev,
	"failed to enable general irq channel: %d\n", ret);

	dev_info(dev, "NXP i.MX SCU Initialized\n");

	return devm_of_platform_populate(dev);
	}

	static const struct of_device_id imx_scu_match[] = {
	{ .compatible = "fsl,imx-scu", },
	{ /* Sentinel */ }
	};

	static struct platform_driver imx_scu_driver = {
	.driver = {
	.name = "imx-scu",
	.of_match_table = imx_scu_match,
	},
	.probe = imx_scu_probe,
	};

	static int __init imx_scu_driver_init(void)
	{
	return platform_driver_register(&imx_scu_driver);
	}
	subsys_initcall_sync(imx_scu_driver_init);

	MODULE_AUTHOR("Dong Aisheng <aisheng.dong@nxp.com>");
	MODULE_DESCRIPTION("IMX SCU firmware protocol driver");
	MODULE_LICENSE("GPL v2");