drivers/misc/mei/init.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2012-2022, Intel Corporation. All rights reserved.
  * Intel Management Engine Interface (Intel MEI) Linux driver
  */

 #include <linux/export.h>
 #include <linux/sched.h>
 #include <linux/wait.h>
 #include <linux/delay.h>

 #include <linux/mei.h>

 #include "mei_dev.h"
 #include "hbm.h"
 #include "client.h"

 const char *mei_dev_state_str(int state)
 {
 #define MEI_DEV_STATE(state) case MEI_DEV_##state: return #state
 	switch (state) {
 	MEI_DEV_STATE(INITIALIZING);
 	MEI_DEV_STATE(INIT_CLIENTS);
 	MEI_DEV_STATE(ENABLED);
 	MEI_DEV_STATE(RESETTING);
 	MEI_DEV_STATE(DISABLED);
 	MEI_DEV_STATE(POWERING_DOWN);
 	MEI_DEV_STATE(POWER_DOWN);
 	MEI_DEV_STATE(POWER_UP);
 	default:
 		return "unknown";
 	}
 #undef MEI_DEV_STATE
 }

 const char *mei_pg_state_str(enum mei_pg_state state)
 {
 #define MEI_PG_STATE(state) case MEI_PG_##state: return #state
 	switch (state) {
 	MEI_PG_STATE(OFF);
 	MEI_PG_STATE(ON);
 	default:
 		return "unknown";
 	}
 #undef MEI_PG_STATE
 }

 /**
  * mei_fw_status2str - convert fw status registers to printable string
  *
  * @fw_status:  firmware status
  * @buf: string buffer at minimal size MEI_FW_STATUS_STR_SZ
  * @len: buffer len must be >= MEI_FW_STATUS_STR_SZ
  *
  * Return: number of bytes written or -EINVAL if buffer is to small
  */
 ssize_t mei_fw_status2str(struct mei_fw_status *fw_status,
 			  char *buf, size_t len)
 {
 	ssize_t cnt = 0;
 	int i;

 	buf[0] = '\0';

 	if (len < MEI_FW_STATUS_STR_SZ)
 		return -EINVAL;

 	for (i = 0; i < fw_status->count; i++)
 		cnt += scnprintf(buf + cnt, len - cnt, "%08X ",
 				fw_status->status[i]);

 	/* drop last space */
 	buf[cnt] = '\0';
 	return cnt;
 }
 EXPORT_SYMBOL_GPL(mei_fw_status2str);

 /**
  * mei_cancel_work - Cancel mei background jobs
  *
  * @dev: the device structure
  */
 void mei_cancel_work(struct mei_device *dev)
 {
 	cancel_work_sync(&dev->reset_work);
 	cancel_work_sync(&dev->bus_rescan_work);

 	cancel_delayed_work_sync(&dev->timer_work);
 }
 EXPORT_SYMBOL_GPL(mei_cancel_work);

 static void mei_save_fw_status(struct mei_device *dev)
 {
 	struct mei_fw_status fw_status;
 	int ret;

 	ret = mei_fw_status(dev, &fw_status);
 	if (ret) {
 		dev_err(dev->dev, "failed to read firmware status: %d\n", ret);
 		return;
 	}

 	dev->saved_dev_state = dev->dev_state;
 	dev->saved_fw_status_flag = true;
 	memcpy(&dev->saved_fw_status, &fw_status, sizeof(fw_status));
 }

 /**
  * mei_reset - resets host and fw.
  *
  * @dev: the device structure
  *
  * Return: 0 on success or < 0 if the reset hasn't succeeded
  */
 int mei_reset(struct mei_device *dev)
 {
 	enum mei_dev_state state = dev->dev_state;
 	bool interrupts_enabled;
 	int ret;

 	if (state != MEI_DEV_INITIALIZING &&
 	    state != MEI_DEV_DISABLED &&
 	    state != MEI_DEV_POWER_DOWN &&
 	    state != MEI_DEV_POWER_UP) {
 		char fw_sts_str[MEI_FW_STATUS_STR_SZ];

 		mei_fw_status_str(dev, fw_sts_str, MEI_FW_STATUS_STR_SZ);
 		if (kind_is_gsc(dev) || kind_is_gscfi(dev)) {
 			dev_dbg(dev->dev, "unexpected reset: dev_state = %s fw status = %s\n",
 				mei_dev_state_str(state), fw_sts_str);
 			mei_save_fw_status(dev);
 		} else {
 			dev_warn(dev->dev, "unexpected reset: dev_state = %s fw status = %s\n",
 				 mei_dev_state_str(state), fw_sts_str);
 		}
 	}

 	mei_clear_interrupts(dev);

 	/* we're already in reset, cancel the init timer
 	 * if the reset was called due the hbm protocol error
 	 * we need to call it before hw start
 	 * so the hbm watchdog won't kick in
 	 */
 	mei_hbm_idle(dev);

 	/* enter reset flow */
 	interrupts_enabled = state != MEI_DEV_POWER_DOWN;
 	mei_set_devstate(dev, MEI_DEV_RESETTING);

 	dev->reset_count++;
 	if (dev->reset_count > MEI_MAX_CONSEC_RESET) {
 		dev_err(dev->dev, "reset: reached maximal consecutive resets: disabling the device\n");
 		mei_set_devstate(dev, MEI_DEV_DISABLED);
 		return -ENODEV;
 	}

 	ret = mei_hw_reset(dev, interrupts_enabled);
 	/* fall through and remove the sw state even if hw reset has failed */

 	/* no need to clean up software state in case of power up */
 	if (state != MEI_DEV_INITIALIZING && state != MEI_DEV_POWER_UP)
 		mei_cl_all_disconnect(dev);

 	mei_hbm_reset(dev);

 	/* clean stale FW version */
 	dev->fw_ver_received = 0;

 	memset(dev->rd_msg_hdr, 0, sizeof(dev->rd_msg_hdr));

 	if (ret) {
 		dev_err(dev->dev, "hw_reset failed ret = %d\n", ret);
 		return ret;
 	}

 	if (state == MEI_DEV_POWER_DOWN) {
 		dev_dbg(dev->dev, "powering down: end of reset\n");
 		mei_set_devstate(dev, MEI_DEV_DISABLED);
 		return 0;
 	}

 	ret = mei_hw_start(dev);
 	if (ret) {
 		char fw_sts_str[MEI_FW_STATUS_STR_SZ];

 		mei_fw_status_str(dev, fw_sts_str, MEI_FW_STATUS_STR_SZ);
 		dev_err(dev->dev, "hw_start failed ret = %d fw status = %s\n", ret, fw_sts_str);
 		return ret;
 	}

 	if (dev->dev_state != MEI_DEV_RESETTING) {
 		dev_dbg(dev->dev, "wrong state = %d on link start\n", dev->dev_state);
 		return 0;
 	}

 	dev_dbg(dev->dev, "link is established start sending messages.\n");

 	mei_set_devstate(dev, MEI_DEV_INIT_CLIENTS);
 	ret = mei_hbm_start_req(dev);
 	if (ret) {
 		dev_err(dev->dev, "hbm_start failed ret = %d\n", ret);
 		mei_set_devstate(dev, MEI_DEV_RESETTING);
 		return ret;
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(mei_reset);

 /**
  * mei_start - initializes host and fw to start work.
  *
  * @dev: the device structure
  *
  * Return: 0 on success, <0 on failure.
  */
 int mei_start(struct mei_device *dev)
 {
 	int ret;

 	mutex_lock(&dev->device_lock);

 	/* acknowledge interrupt and stop interrupts */
 	mei_clear_interrupts(dev);

 	ret = mei_hw_config(dev);
 	if (ret)
 		goto err;

 	dev_dbg(dev->dev, "reset in start the mei device.\n");

 	dev->reset_count = 0;
 	do {
 		mei_set_devstate(dev, MEI_DEV_INITIALIZING);
 		ret = mei_reset(dev);

 		if (ret == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
 			dev_err(dev->dev, "reset failed ret = %d", ret);
 			goto err;
 		}
 	} while (ret);

 	if (mei_hbm_start_wait(dev)) {
 		dev_err(dev->dev, "HBM haven't started");
 		goto err;
 	}

 	if (!mei_hbm_version_is_supported(dev)) {
 		dev_dbg(dev->dev, "MEI start failed.\n");
 		goto err;
 	}

 	dev_dbg(dev->dev, "link layer has been established.\n");

 	mutex_unlock(&dev->device_lock);
 	return 0;
 err:
 	dev_err(dev->dev, "link layer initialization failed.\n");
 	mei_set_devstate(dev, MEI_DEV_DISABLED);
 	mutex_unlock(&dev->device_lock);
 	return -ENODEV;
 }
 EXPORT_SYMBOL_GPL(mei_start);

 /**
  * mei_restart - restart device after suspend
  *
  * @dev: the device structure
  *
  * Return: 0 on success or -ENODEV if the restart hasn't succeeded
  */
 int mei_restart(struct mei_device *dev)
 {
 	int err;

 	mutex_lock(&dev->device_lock);

 	mei_set_devstate(dev, MEI_DEV_POWER_UP);
 	dev->reset_count = 0;

 	err = mei_reset(dev);

 	mutex_unlock(&dev->device_lock);

 	if (err == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
 		dev_err(dev->dev, "device disabled = %d\n", err);
 		return -ENODEV;
 	}

 	/* try to start again */
 	if (err)
 		schedule_work(&dev->reset_work);


 	return 0;
 }
 EXPORT_SYMBOL_GPL(mei_restart);

 static void mei_reset_work(struct work_struct *work)
 {
 	struct mei_device *dev =
 		container_of(work, struct mei_device,  reset_work);
 	int ret;

 	mei_clear_interrupts(dev);
 	mei_synchronize_irq(dev);

 	mutex_lock(&dev->device_lock);

 	ret = mei_reset(dev);

 	mutex_unlock(&dev->device_lock);

 	if (dev->dev_state == MEI_DEV_DISABLED) {
 		dev_err(dev->dev, "device disabled = %d\n", ret);
 		return;
 	}

 	/* retry reset in case of failure */
 	if (ret)
 		schedule_work(&dev->reset_work);
 }

 void mei_stop(struct mei_device *dev)
 {
 	dev_dbg(dev->dev, "stopping the device.\n");

 	mutex_lock(&dev->device_lock);
 	mei_set_devstate(dev, MEI_DEV_POWERING_DOWN);
 	mutex_unlock(&dev->device_lock);
 	mei_cl_bus_remove_devices(dev);
 	mutex_lock(&dev->device_lock);
 	mei_set_devstate(dev, MEI_DEV_POWER_DOWN);
 	mutex_unlock(&dev->device_lock);

 	mei_cancel_work(dev);

 	mei_clear_interrupts(dev);
 	mei_synchronize_irq(dev);
 	/* to catch HW-initiated reset */
 	mei_cancel_work(dev);

 	mutex_lock(&dev->device_lock);

 	mei_reset(dev);
 	/* move device to disabled state unconditionally */
 	mei_set_devstate(dev, MEI_DEV_DISABLED);

 	mutex_unlock(&dev->device_lock);
 }
 EXPORT_SYMBOL_GPL(mei_stop);

 /**
  * mei_write_is_idle - check if the write queues are idle
  *
  * @dev: the device structure
  *
  * Return: true of there is no pending write
  */
 bool mei_write_is_idle(struct mei_device *dev)
 {
 	bool idle = (dev->dev_state == MEI_DEV_ENABLED &&
 		list_empty(&dev->ctrl_wr_list) &&
 		list_empty(&dev->write_list)   &&
 		list_empty(&dev->write_waiting_list));

 	dev_dbg(dev->dev, "write pg: is idle[%d] state=%s ctrl=%01d write=%01d wwait=%01d\n",
 		idle,
 		mei_dev_state_str(dev->dev_state),
 		list_empty(&dev->ctrl_wr_list),
 		list_empty(&dev->write_list),
 		list_empty(&dev->write_waiting_list));

 	return idle;
 }
 EXPORT_SYMBOL_GPL(mei_write_is_idle);

 /**
  * mei_device_init - initialize mei_device structure
  *
  * @dev: the mei device
  * @device: the device structure
  * @slow_fw: configure longer timeouts as FW is slow
  * @hw_ops: hw operations
  */
 void mei_device_init(struct mei_device *dev,
 		     struct device *device,
 		     bool slow_fw,
 		     const struct mei_hw_ops *hw_ops)
 {
 	/* setup our list array */
 	INIT_LIST_HEAD(&dev->file_list);
 	INIT_LIST_HEAD(&dev->device_list);
 	INIT_LIST_HEAD(&dev->me_clients);
 	mutex_init(&dev->device_lock);
 	init_rwsem(&dev->me_clients_rwsem);
 	mutex_init(&dev->cl_bus_lock);
 	init_waitqueue_head(&dev->wait_hw_ready);
 	init_waitqueue_head(&dev->wait_pg);
 	init_waitqueue_head(&dev->wait_hbm_start);
 	dev->dev_state = MEI_DEV_INITIALIZING;
 	dev->reset_count = 0;

 	INIT_LIST_HEAD(&dev->write_list);
 	INIT_LIST_HEAD(&dev->write_waiting_list);
 	INIT_LIST_HEAD(&dev->ctrl_wr_list);
 	INIT_LIST_HEAD(&dev->ctrl_rd_list);
 	dev->tx_queue_limit = MEI_TX_QUEUE_LIMIT_DEFAULT;

 	INIT_DELAYED_WORK(&dev->timer_work, mei_timer);
 	INIT_WORK(&dev->reset_work, mei_reset_work);
 	INIT_WORK(&dev->bus_rescan_work, mei_cl_bus_rescan_work);

 	bitmap_zero(dev->host_clients_map, MEI_CLIENTS_MAX);
 	dev->open_handle_count = 0;

 	dev->pxp_mode = MEI_DEV_PXP_DEFAULT;
 	dev->gsc_reset_to_pxp = MEI_DEV_RESET_TO_PXP_DEFAULT;

 	/*
 	 * Reserving the first client ID
 	 * 0: Reserved for MEI Bus Message communications
 	 */
 	bitmap_set(dev->host_clients_map, 0, 1);

 	dev->pg_event = MEI_PG_EVENT_IDLE;
 	dev->ops      = hw_ops;
 	dev->dev      = device;

 	dev->timeouts.hw_ready = mei_secs_to_jiffies(MEI_HW_READY_TIMEOUT);
 	dev->timeouts.connect = MEI_CONNECT_TIMEOUT;
 	dev->timeouts.client_init = MEI_CLIENTS_INIT_TIMEOUT;
 	dev->timeouts.pgi = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
 	dev->timeouts.d0i3 = mei_secs_to_jiffies(MEI_D0I3_TIMEOUT);
 	if (slow_fw) {
 		dev->timeouts.cl_connect = mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT_SLOW);
 		dev->timeouts.hbm = mei_secs_to_jiffies(MEI_HBM_TIMEOUT_SLOW);
 		dev->timeouts.mkhi_recv = msecs_to_jiffies(MKHI_RCV_TIMEOUT_SLOW);
 	} else {
 		dev->timeouts.cl_connect = mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT);
 		dev->timeouts.hbm = mei_secs_to_jiffies(MEI_HBM_TIMEOUT);
 		dev->timeouts.mkhi_recv = msecs_to_jiffies(MKHI_RCV_TIMEOUT);
 	}
 }
 EXPORT_SYMBOL_GPL(mei_device_init);
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright (c) 2012-2022, Intel Corporation. All rights reserved.
	* Intel Management Engine Interface (Intel MEI) Linux driver
	*/

	#include <linux/export.h>
	#include <linux/sched.h>
	#include <linux/wait.h>
	#include <linux/delay.h>

	#include <linux/mei.h>

	#include "mei_dev.h"
	#include "hbm.h"
	#include "client.h"

	const char *mei_dev_state_str(int state)
	{
	#define MEI_DEV_STATE(state) case MEI_DEV_##state: return #state
	switch (state) {
	MEI_DEV_STATE(INITIALIZING);
	MEI_DEV_STATE(INIT_CLIENTS);
	MEI_DEV_STATE(ENABLED);
	MEI_DEV_STATE(RESETTING);
	MEI_DEV_STATE(DISABLED);
	MEI_DEV_STATE(POWERING_DOWN);
	MEI_DEV_STATE(POWER_DOWN);
	MEI_DEV_STATE(POWER_UP);
	default:
	return "unknown";
	}
	#undef MEI_DEV_STATE
	}

	const char *mei_pg_state_str(enum mei_pg_state state)
	{
	#define MEI_PG_STATE(state) case MEI_PG_##state: return #state
	switch (state) {
	MEI_PG_STATE(OFF);
	MEI_PG_STATE(ON);
	default:
	return "unknown";
	}
	#undef MEI_PG_STATE
	}

	/**
	* mei_fw_status2str - convert fw status registers to printable string
	*
	* @fw_status: firmware status
	* @buf: string buffer at minimal size MEI_FW_STATUS_STR_SZ
	* @len: buffer len must be >= MEI_FW_STATUS_STR_SZ
	*
	* Return: number of bytes written or -EINVAL if buffer is to small
	*/
	ssize_t mei_fw_status2str(struct mei_fw_status *fw_status,
	char *buf, size_t len)
	{
	ssize_t cnt = 0;
	int i;

	buf[0] = '\0';

	if (len < MEI_FW_STATUS_STR_SZ)
	return -EINVAL;

	for (i = 0; i < fw_status->count; i++)
	cnt += scnprintf(buf + cnt, len - cnt, "%08X ",
	fw_status->status[i]);

	/* drop last space */
	buf[cnt] = '\0';
	return cnt;
	}
	EXPORT_SYMBOL_GPL(mei_fw_status2str);

	/**
	* mei_cancel_work - Cancel mei background jobs
	*
	* @dev: the device structure
	*/
	void mei_cancel_work(struct mei_device *dev)
	{
	cancel_work_sync(&dev->reset_work);
	cancel_work_sync(&dev->bus_rescan_work);

	cancel_delayed_work_sync(&dev->timer_work);
	}
	EXPORT_SYMBOL_GPL(mei_cancel_work);

	static void mei_save_fw_status(struct mei_device *dev)
	{
	struct mei_fw_status fw_status;
	int ret;

	ret = mei_fw_status(dev, &fw_status);
	if (ret) {
	dev_err(dev->dev, "failed to read firmware status: %d\n", ret);
	return;
	}

	dev->saved_dev_state = dev->dev_state;
	dev->saved_fw_status_flag = true;
	memcpy(&dev->saved_fw_status, &fw_status, sizeof(fw_status));
	}

	/**
	* mei_reset - resets host and fw.
	*
	* @dev: the device structure
	*
	* Return: 0 on success or < 0 if the reset hasn't succeeded
	*/
	int mei_reset(struct mei_device *dev)
	{
	enum mei_dev_state state = dev->dev_state;
	bool interrupts_enabled;
	int ret;

	if (state != MEI_DEV_INITIALIZING &&
	state != MEI_DEV_DISABLED &&
	state != MEI_DEV_POWER_DOWN &&
	state != MEI_DEV_POWER_UP) {
	char fw_sts_str[MEI_FW_STATUS_STR_SZ];

	mei_fw_status_str(dev, fw_sts_str, MEI_FW_STATUS_STR_SZ);
	if (kind_is_gsc(dev) \|\| kind_is_gscfi(dev)) {
	dev_dbg(dev->dev, "unexpected reset: dev_state = %s fw status = %s\n",
	mei_dev_state_str(state), fw_sts_str);
	mei_save_fw_status(dev);
	} else {
	dev_warn(dev->dev, "unexpected reset: dev_state = %s fw status = %s\n",
	mei_dev_state_str(state), fw_sts_str);
	}
	}

	mei_clear_interrupts(dev);

	/* we're already in reset, cancel the init timer
	* if the reset was called due the hbm protocol error
	* we need to call it before hw start
	* so the hbm watchdog won't kick in
	*/
	mei_hbm_idle(dev);

	/* enter reset flow */
	interrupts_enabled = state != MEI_DEV_POWER_DOWN;
	mei_set_devstate(dev, MEI_DEV_RESETTING);

	dev->reset_count++;
	if (dev->reset_count > MEI_MAX_CONSEC_RESET) {
	dev_err(dev->dev, "reset: reached maximal consecutive resets: disabling the device\n");
	mei_set_devstate(dev, MEI_DEV_DISABLED);
	return -ENODEV;
	}

	ret = mei_hw_reset(dev, interrupts_enabled);
	/* fall through and remove the sw state even if hw reset has failed */

	/* no need to clean up software state in case of power up */
	if (state != MEI_DEV_INITIALIZING && state != MEI_DEV_POWER_UP)
	mei_cl_all_disconnect(dev);

	mei_hbm_reset(dev);

	/* clean stale FW version */
	dev->fw_ver_received = 0;

	memset(dev->rd_msg_hdr, 0, sizeof(dev->rd_msg_hdr));

	if (ret) {
	dev_err(dev->dev, "hw_reset failed ret = %d\n", ret);
	return ret;
	}

	if (state == MEI_DEV_POWER_DOWN) {
	dev_dbg(dev->dev, "powering down: end of reset\n");
	mei_set_devstate(dev, MEI_DEV_DISABLED);
	return 0;
	}

	ret = mei_hw_start(dev);
	if (ret) {
	char fw_sts_str[MEI_FW_STATUS_STR_SZ];

	mei_fw_status_str(dev, fw_sts_str, MEI_FW_STATUS_STR_SZ);
	dev_err(dev->dev, "hw_start failed ret = %d fw status = %s\n", ret, fw_sts_str);
	return ret;
	}

	if (dev->dev_state != MEI_DEV_RESETTING) {
	dev_dbg(dev->dev, "wrong state = %d on link start\n", dev->dev_state);
	return 0;
	}

	dev_dbg(dev->dev, "link is established start sending messages.\n");

	mei_set_devstate(dev, MEI_DEV_INIT_CLIENTS);
	ret = mei_hbm_start_req(dev);
	if (ret) {
	dev_err(dev->dev, "hbm_start failed ret = %d\n", ret);
	mei_set_devstate(dev, MEI_DEV_RESETTING);
	return ret;
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(mei_reset);

	/**
	* mei_start - initializes host and fw to start work.
	*
	* @dev: the device structure
	*
	* Return: 0 on success, <0 on failure.
	*/
	int mei_start(struct mei_device *dev)
	{
	int ret;

	mutex_lock(&dev->device_lock);

	/* acknowledge interrupt and stop interrupts */
	mei_clear_interrupts(dev);

	ret = mei_hw_config(dev);
	if (ret)
	goto err;

	dev_dbg(dev->dev, "reset in start the mei device.\n");

	dev->reset_count = 0;
	do {
	mei_set_devstate(dev, MEI_DEV_INITIALIZING);
	ret = mei_reset(dev);

	if (ret == -ENODEV \|\| dev->dev_state == MEI_DEV_DISABLED) {
	dev_err(dev->dev, "reset failed ret = %d", ret);
	goto err;
	}
	} while (ret);

	if (mei_hbm_start_wait(dev)) {
	dev_err(dev->dev, "HBM haven't started");
	goto err;
	}

	if (!mei_hbm_version_is_supported(dev)) {
	dev_dbg(dev->dev, "MEI start failed.\n");
	goto err;
	}

	dev_dbg(dev->dev, "link layer has been established.\n");

	mutex_unlock(&dev->device_lock);
	return 0;
	err:
	dev_err(dev->dev, "link layer initialization failed.\n");
	mei_set_devstate(dev, MEI_DEV_DISABLED);
	mutex_unlock(&dev->device_lock);
	return -ENODEV;
	}
	EXPORT_SYMBOL_GPL(mei_start);

	/**
	* mei_restart - restart device after suspend
	*
	* @dev: the device structure
	*
	* Return: 0 on success or -ENODEV if the restart hasn't succeeded
	*/
	int mei_restart(struct mei_device *dev)
	{
	int err;

	mutex_lock(&dev->device_lock);

	mei_set_devstate(dev, MEI_DEV_POWER_UP);
	dev->reset_count = 0;

	err = mei_reset(dev);

	mutex_unlock(&dev->device_lock);

	if (err == -ENODEV \|\| dev->dev_state == MEI_DEV_DISABLED) {
	dev_err(dev->dev, "device disabled = %d\n", err);
	return -ENODEV;
	}

	/* try to start again */
	if (err)
	schedule_work(&dev->reset_work);


	return 0;
	}
	EXPORT_SYMBOL_GPL(mei_restart);

	static void mei_reset_work(struct work_struct *work)
	{
	struct mei_device *dev =
	container_of(work, struct mei_device, reset_work);
	int ret;

	mei_clear_interrupts(dev);
	mei_synchronize_irq(dev);

	mutex_lock(&dev->device_lock);

	ret = mei_reset(dev);

	mutex_unlock(&dev->device_lock);

	if (dev->dev_state == MEI_DEV_DISABLED) {
	dev_err(dev->dev, "device disabled = %d\n", ret);
	return;
	}

	/* retry reset in case of failure */
	if (ret)
	schedule_work(&dev->reset_work);
	}

	void mei_stop(struct mei_device *dev)
	{
	dev_dbg(dev->dev, "stopping the device.\n");

	mutex_lock(&dev->device_lock);
	mei_set_devstate(dev, MEI_DEV_POWERING_DOWN);
	mutex_unlock(&dev->device_lock);
	mei_cl_bus_remove_devices(dev);
	mutex_lock(&dev->device_lock);
	mei_set_devstate(dev, MEI_DEV_POWER_DOWN);
	mutex_unlock(&dev->device_lock);

	mei_cancel_work(dev);

	mei_clear_interrupts(dev);
	mei_synchronize_irq(dev);
	/* to catch HW-initiated reset */
	mei_cancel_work(dev);

	mutex_lock(&dev->device_lock);

	mei_reset(dev);
	/* move device to disabled state unconditionally */
	mei_set_devstate(dev, MEI_DEV_DISABLED);

	mutex_unlock(&dev->device_lock);
	}
	EXPORT_SYMBOL_GPL(mei_stop);

	/**
	* mei_write_is_idle - check if the write queues are idle
	*
	* @dev: the device structure
	*
	* Return: true of there is no pending write
	*/
	bool mei_write_is_idle(struct mei_device *dev)
	{
	bool idle = (dev->dev_state == MEI_DEV_ENABLED &&
	list_empty(&dev->ctrl_wr_list) &&
	list_empty(&dev->write_list) &&
	list_empty(&dev->write_waiting_list));

	dev_dbg(dev->dev, "write pg: is idle[%d] state=%s ctrl=%01d write=%01d wwait=%01d\n",
	idle,
	mei_dev_state_str(dev->dev_state),
	list_empty(&dev->ctrl_wr_list),
	list_empty(&dev->write_list),
	list_empty(&dev->write_waiting_list));

	return idle;
	}
	EXPORT_SYMBOL_GPL(mei_write_is_idle);

	/**
	* mei_device_init - initialize mei_device structure
	*
	* @dev: the mei device
	* @device: the device structure
	* @slow_fw: configure longer timeouts as FW is slow
	* @hw_ops: hw operations
	*/
	void mei_device_init(struct mei_device *dev,
	struct device *device,
	bool slow_fw,
	const struct mei_hw_ops *hw_ops)
	{
	/* setup our list array */
	INIT_LIST_HEAD(&dev->file_list);
	INIT_LIST_HEAD(&dev->device_list);
	INIT_LIST_HEAD(&dev->me_clients);
	mutex_init(&dev->device_lock);
	init_rwsem(&dev->me_clients_rwsem);
	mutex_init(&dev->cl_bus_lock);
	init_waitqueue_head(&dev->wait_hw_ready);
	init_waitqueue_head(&dev->wait_pg);
	init_waitqueue_head(&dev->wait_hbm_start);
	dev->dev_state = MEI_DEV_INITIALIZING;
	dev->reset_count = 0;

	INIT_LIST_HEAD(&dev->write_list);
	INIT_LIST_HEAD(&dev->write_waiting_list);
	INIT_LIST_HEAD(&dev->ctrl_wr_list);
	INIT_LIST_HEAD(&dev->ctrl_rd_list);
	dev->tx_queue_limit = MEI_TX_QUEUE_LIMIT_DEFAULT;

	INIT_DELAYED_WORK(&dev->timer_work, mei_timer);
	INIT_WORK(&dev->reset_work, mei_reset_work);
	INIT_WORK(&dev->bus_rescan_work, mei_cl_bus_rescan_work);

	bitmap_zero(dev->host_clients_map, MEI_CLIENTS_MAX);
	dev->open_handle_count = 0;

	dev->pxp_mode = MEI_DEV_PXP_DEFAULT;
	dev->gsc_reset_to_pxp = MEI_DEV_RESET_TO_PXP_DEFAULT;

	/*
	* Reserving the first client ID
	* 0: Reserved for MEI Bus Message communications
	*/
	bitmap_set(dev->host_clients_map, 0, 1);

	dev->pg_event = MEI_PG_EVENT_IDLE;
	dev->ops = hw_ops;
	dev->dev = device;

	dev->timeouts.hw_ready = mei_secs_to_jiffies(MEI_HW_READY_TIMEOUT);
	dev->timeouts.connect = MEI_CONNECT_TIMEOUT;
	dev->timeouts.client_init = MEI_CLIENTS_INIT_TIMEOUT;
	dev->timeouts.pgi = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
	dev->timeouts.d0i3 = mei_secs_to_jiffies(MEI_D0I3_TIMEOUT);
	if (slow_fw) {
	dev->timeouts.cl_connect = mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT_SLOW);
	dev->timeouts.hbm = mei_secs_to_jiffies(MEI_HBM_TIMEOUT_SLOW);
	dev->timeouts.mkhi_recv = msecs_to_jiffies(MKHI_RCV_TIMEOUT_SLOW);
	} else {
	dev->timeouts.cl_connect = mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT);
	dev->timeouts.hbm = mei_secs_to_jiffies(MEI_HBM_TIMEOUT);
	dev->timeouts.mkhi_recv = msecs_to_jiffies(MKHI_RCV_TIMEOUT);
	}
	}
	EXPORT_SYMBOL_GPL(mei_device_init);