drivers/platform/chrome/cros_ec_debugfs.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 // Debug logs for the ChromeOS EC
 //
 // Copyright (C) 2015 Google, Inc.

 #include <linux/circ_buf.h>
 #include <linux/debugfs.h>
 #include <linux/delay.h>
 #include <linux/fs.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/platform_data/cros_ec_commands.h>
 #include <linux/platform_data/cros_ec_proto.h>
 #include <linux/platform_device.h>
 #include <linux/poll.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/wait.h>

 #define DRV_NAME "cros-ec-debugfs"

 #define LOG_SHIFT		14
 #define LOG_SIZE		(1 << LOG_SHIFT)
 #define LOG_POLL_SEC		10

 #define CIRC_ADD(idx, size, value)	(((idx) + (value)) & ((size) - 1))

 static unsigned int log_poll_period_ms = LOG_POLL_SEC * MSEC_PER_SEC;
 module_param(log_poll_period_ms, uint, 0644);
 MODULE_PARM_DESC(log_poll_period_ms, "EC log polling period(ms)");

 /* waitqueue for log readers */
 static DECLARE_WAIT_QUEUE_HEAD(cros_ec_debugfs_log_wq);

 /**
  * struct cros_ec_debugfs - EC debugging information.
  *
  * @ec: EC device this debugfs information belongs to
  * @dir: dentry for debugfs files
  * @log_buffer: circular buffer for console log information
  * @read_msg: preallocated EC command and buffer to read console log
  * @log_mutex: mutex to protect circular buffer
  * @log_poll_work: recurring task to poll EC for new console log data
  * @panicinfo_blob: panicinfo debugfs blob
  * @notifier_panic: notifier_block to let kernel to flush buffered log
  *                  when EC panic
  */
 struct cros_ec_debugfs {
 	struct cros_ec_dev *ec;
 	struct dentry *dir;
 	/* EC log */
 	struct circ_buf log_buffer;
 	struct cros_ec_command *read_msg;
 	struct mutex log_mutex;
 	struct delayed_work log_poll_work;
 	/* EC panicinfo */
 	struct debugfs_blob_wrapper panicinfo_blob;
 	struct notifier_block notifier_panic;
 };

 /*
  * We need to make sure that the EC log buffer on the UART is large enough,
  * so that it is unlikely enough to overlow within log_poll_period_ms.
  */
 static void cros_ec_console_log_work(struct work_struct *__work)
 {
 	struct cros_ec_debugfs *debug_info =
 		container_of(to_delayed_work(__work),
 			     struct cros_ec_debugfs,
 			     log_poll_work);
 	struct cros_ec_dev *ec = debug_info->ec;
 	struct circ_buf *cb = &debug_info->log_buffer;
 	struct cros_ec_command snapshot_msg = {
 		.command = EC_CMD_CONSOLE_SNAPSHOT + ec->cmd_offset,
 	};

 	struct ec_params_console_read_v1 *read_params =
 		(struct ec_params_console_read_v1 *)debug_info->read_msg->data;
 	uint8_t *ec_buffer = (uint8_t *)debug_info->read_msg->data;
 	int idx;
 	int buf_space;
 	int ret;

 	ret = cros_ec_cmd_xfer_status(ec->ec_dev, &snapshot_msg);
 	if (ret < 0)
 		goto resched;

 	/* Loop until we have read everything, or there's an error. */
 	mutex_lock(&debug_info->log_mutex);
 	buf_space = CIRC_SPACE(cb->head, cb->tail, LOG_SIZE);

 	while (1) {
 		if (!buf_space) {
 			dev_info_once(ec->dev,
 				      "Some logs may have been dropped...\n");
 			break;
 		}

 		memset(read_params, '\0', sizeof(*read_params));
 		read_params->subcmd = CONSOLE_READ_RECENT;
 		ret = cros_ec_cmd_xfer_status(ec->ec_dev,
 					      debug_info->read_msg);
 		if (ret < 0)
 			break;

 		/* If the buffer is empty, we're done here. */
 		if (ret == 0 || ec_buffer[0] == '\0')
 			break;

 		idx = 0;
 		while (idx < ret && ec_buffer[idx] != '\0' && buf_space > 0) {
 			cb->buf[cb->head] = ec_buffer[idx];
 			cb->head = CIRC_ADD(cb->head, LOG_SIZE, 1);
 			idx++;
 			buf_space--;
 		}

 		wake_up(&cros_ec_debugfs_log_wq);
 	}

 	mutex_unlock(&debug_info->log_mutex);

 resched:
 	schedule_delayed_work(&debug_info->log_poll_work,
 			      msecs_to_jiffies(log_poll_period_ms));
 }

 static int cros_ec_console_log_open(struct inode *inode, struct file *file)
 {
 	file->private_data = inode->i_private;

 	return stream_open(inode, file);
 }

 static ssize_t cros_ec_console_log_read(struct file *file, char __user *buf,
 					size_t count, loff_t *ppos)
 {
 	struct cros_ec_debugfs *debug_info = file->private_data;
 	struct circ_buf *cb = &debug_info->log_buffer;
 	ssize_t ret;

 	mutex_lock(&debug_info->log_mutex);

 	while (!CIRC_CNT(cb->head, cb->tail, LOG_SIZE)) {
 		if (file->f_flags & O_NONBLOCK) {
 			ret = -EAGAIN;
 			goto error;
 		}

 		mutex_unlock(&debug_info->log_mutex);

 		ret = wait_event_interruptible(cros_ec_debugfs_log_wq,
 					CIRC_CNT(cb->head, cb->tail, LOG_SIZE));
 		if (ret < 0)
 			return ret;

 		mutex_lock(&debug_info->log_mutex);
 	}

 	/* Only copy until the end of the circular buffer, and let userspace
 	 * retry to get the rest of the data.
 	 */
 	ret = min_t(size_t, CIRC_CNT_TO_END(cb->head, cb->tail, LOG_SIZE),
 		    count);

 	if (copy_to_user(buf, cb->buf + cb->tail, ret)) {
 		ret = -EFAULT;
 		goto error;
 	}

 	cb->tail = CIRC_ADD(cb->tail, LOG_SIZE, ret);

 error:
 	mutex_unlock(&debug_info->log_mutex);
 	return ret;
 }

 static __poll_t cros_ec_console_log_poll(struct file *file,
 					     poll_table *wait)
 {
 	struct cros_ec_debugfs *debug_info = file->private_data;
 	__poll_t mask = 0;

 	poll_wait(file, &cros_ec_debugfs_log_wq, wait);

 	mutex_lock(&debug_info->log_mutex);
 	if (CIRC_CNT(debug_info->log_buffer.head,
 		     debug_info->log_buffer.tail,
 		     LOG_SIZE))
 		mask |= EPOLLIN | EPOLLRDNORM;
 	mutex_unlock(&debug_info->log_mutex);

 	return mask;
 }

 static int cros_ec_console_log_release(struct inode *inode, struct file *file)
 {
 	return 0;
 }

 static ssize_t cros_ec_pdinfo_read(struct file *file,
 				   char __user *user_buf,
 				   size_t count,
 				   loff_t *ppos)
 {
 	char read_buf[EC_USB_PD_MAX_PORTS * 40], *p = read_buf;
 	struct cros_ec_debugfs *debug_info = file->private_data;
 	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
 	struct {
 		struct cros_ec_command msg;
 		union {
 			struct ec_response_usb_pd_control_v1 resp;
 			struct ec_params_usb_pd_control params;
 		};
 	} __packed ec_buf;
 	struct cros_ec_command *msg;
 	struct ec_response_usb_pd_control_v1 *resp;
 	struct ec_params_usb_pd_control *params;
 	int i;

 	msg = &ec_buf.msg;
 	params = (struct ec_params_usb_pd_control *)msg->data;
 	resp = (struct ec_response_usb_pd_control_v1 *)msg->data;

 	msg->command = EC_CMD_USB_PD_CONTROL;
 	msg->version = 1;
 	msg->insize = sizeof(*resp);
 	msg->outsize = sizeof(*params);

 	/*
 	 * Read status from all PD ports until failure, typically caused
 	 * by attempting to read status on a port that doesn't exist.
 	 */
 	for (i = 0; i < EC_USB_PD_MAX_PORTS; ++i) {
 		params->port = i;
 		params->role = 0;
 		params->mux = 0;
 		params->swap = 0;

 		if (cros_ec_cmd_xfer_status(ec_dev, msg) < 0)
 			break;

 		p += scnprintf(p, sizeof(read_buf) + read_buf - p,
 			       "p%d: %s en:%.2x role:%.2x pol:%.2x\n", i,
 			       resp->state, resp->enabled, resp->role,
 			       resp->polarity);
 	}

 	return simple_read_from_buffer(user_buf, count, ppos,
 				       read_buf, p - read_buf);
 }

 static bool cros_ec_uptime_is_supported(struct cros_ec_device *ec_dev)
 {
 	struct {
 		struct cros_ec_command cmd;
 		struct ec_response_uptime_info resp;
 	} __packed msg = {};
 	int ret;

 	msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
 	msg.cmd.insize = sizeof(msg.resp);

 	ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
 	if (ret == -EPROTO && msg.cmd.result == EC_RES_INVALID_COMMAND)
 		return false;

 	/* Other errors maybe a transient error, do not rule about support. */
 	return true;
 }

 static ssize_t cros_ec_uptime_read(struct file *file, char __user *user_buf,
 				   size_t count, loff_t *ppos)
 {
 	struct cros_ec_debugfs *debug_info = file->private_data;
 	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
 	struct {
 		struct cros_ec_command cmd;
 		struct ec_response_uptime_info resp;
 	} __packed msg = {};
 	struct ec_response_uptime_info *resp;
 	char read_buf[32];
 	int ret;

 	resp = (struct ec_response_uptime_info *)&msg.resp;

 	msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
 	msg.cmd.insize = sizeof(*resp);

 	ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
 	if (ret < 0)
 		return ret;

 	ret = scnprintf(read_buf, sizeof(read_buf), "%u\n",
 			resp->time_since_ec_boot_ms);

 	return simple_read_from_buffer(user_buf, count, ppos, read_buf, ret);
 }

 static const struct file_operations cros_ec_console_log_fops = {
 	.owner = THIS_MODULE,
 	.open = cros_ec_console_log_open,
 	.read = cros_ec_console_log_read,
 	.poll = cros_ec_console_log_poll,
 	.release = cros_ec_console_log_release,
 };

 static const struct file_operations cros_ec_pdinfo_fops = {
 	.owner = THIS_MODULE,
 	.open = simple_open,
 	.read = cros_ec_pdinfo_read,
 	.llseek = default_llseek,
 };

 static const struct file_operations cros_ec_uptime_fops = {
 	.owner = THIS_MODULE,
 	.open = simple_open,
 	.read = cros_ec_uptime_read,
 	.llseek = default_llseek,
 };

 static int ec_read_version_supported(struct cros_ec_dev *ec)
 {
 	struct ec_params_get_cmd_versions_v1 *params;
 	struct ec_response_get_cmd_versions *response;
 	int ret;

 	struct cros_ec_command *msg;

 	msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)),
 		GFP_KERNEL);
 	if (!msg)
 		return 0;

 	msg->version = 1;
 	msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
 	msg->outsize = sizeof(*params);
 	msg->insize = sizeof(*response);

 	params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
 	params->cmd = EC_CMD_CONSOLE_READ;
 	response = (struct ec_response_get_cmd_versions *)msg->data;

 	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg) >= 0 &&
 	      response->version_mask & EC_VER_MASK(1);

 	kfree(msg);

 	return ret;
 }

 static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
 {
 	struct cros_ec_dev *ec = debug_info->ec;
 	char *buf;
 	int read_params_size;
 	int read_response_size;

 	/*
 	 * If the console log feature is not supported return silently and
 	 * don't create the console_log entry.
 	 */
 	if (!ec_read_version_supported(ec))
 		return 0;

 	buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;

 	read_params_size = sizeof(struct ec_params_console_read_v1);
 	read_response_size = ec->ec_dev->max_response;
 	debug_info->read_msg = devm_kzalloc(ec->dev,
 		sizeof(*debug_info->read_msg) +
 			max(read_params_size, read_response_size), GFP_KERNEL);
 	if (!debug_info->read_msg)
 		return -ENOMEM;

 	debug_info->read_msg->version = 1;
 	debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
 	debug_info->read_msg->outsize = read_params_size;
 	debug_info->read_msg->insize = read_response_size;

 	debug_info->log_buffer.buf = buf;
 	debug_info->log_buffer.head = 0;
 	debug_info->log_buffer.tail = 0;

 	mutex_init(&debug_info->log_mutex);

 	debugfs_create_file("console_log", S_IFREG | 0444, debug_info->dir,
 			    debug_info, &cros_ec_console_log_fops);

 	INIT_DELAYED_WORK(&debug_info->log_poll_work,
 			  cros_ec_console_log_work);
 	schedule_delayed_work(&debug_info->log_poll_work, 0);

 	return 0;
 }

 static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
 {
 	if (debug_info->log_buffer.buf) {
 		cancel_delayed_work_sync(&debug_info->log_poll_work);
 		mutex_destroy(&debug_info->log_mutex);
 	}
 }

 /*
  * Returns the size of the panicinfo data fetched from the EC
  */
 static int cros_ec_get_panicinfo(struct cros_ec_device *ec_dev, uint8_t *data,
 				 int data_size)
 {
 	int ret;
 	struct cros_ec_command *msg;

 	if (!data || data_size <= 0 || data_size > ec_dev->max_response)
 		return -EINVAL;

 	msg = kzalloc(sizeof(*msg) + data_size, GFP_KERNEL);
 	if (!msg)
 		return -ENOMEM;

 	msg->command = EC_CMD_GET_PANIC_INFO;
 	msg->insize = data_size;

 	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
 	if (ret < 0)
 		goto free;

 	memcpy(data, msg->data, data_size);

 free:
 	kfree(msg);
 	return ret;
 }

 static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
 {
 	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
 	int ret;
 	void *data;

 	data = devm_kzalloc(debug_info->ec->dev, ec_dev->max_response,
 			    GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 	ret = cros_ec_get_panicinfo(ec_dev, data, ec_dev->max_response);
 	if (ret < 0) {
 		ret = 0;
 		goto free;
 	}

 	/* No panic data */
 	if (ret == 0)
 		goto free;

 	debug_info->panicinfo_blob.data = data;
 	debug_info->panicinfo_blob.size = ret;

 	debugfs_create_blob("panicinfo", 0444, debug_info->dir,
 			    &debug_info->panicinfo_blob);

 	return 0;

 free:
 	devm_kfree(debug_info->ec->dev, data);
 	return ret;
 }

 static int cros_ec_debugfs_panic_event(struct notifier_block *nb,
 				       unsigned long queued_during_suspend, void *_notify)
 {
 	struct cros_ec_debugfs *debug_info =
 		container_of(nb, struct cros_ec_debugfs, notifier_panic);

 	if (debug_info->log_buffer.buf) {
 		/* Force log poll work to run immediately */
 		mod_delayed_work(debug_info->log_poll_work.wq, &debug_info->log_poll_work, 0);
 		/* Block until log poll work finishes */
 		flush_delayed_work(&debug_info->log_poll_work);
 	}

 	return NOTIFY_DONE;
 }

 static int cros_ec_debugfs_probe(struct platform_device *pd)
 {
 	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
 	struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
 	const char *name = ec_platform->ec_name;
 	struct cros_ec_debugfs *debug_info;
 	int ret;

 	debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
 	if (!debug_info)
 		return -ENOMEM;

 	debug_info->ec = ec;
 	debug_info->dir = debugfs_create_dir(name, NULL);

 	ret = cros_ec_create_panicinfo(debug_info);
 	if (ret)
 		goto remove_debugfs;

 	ret = cros_ec_create_console_log(debug_info);
 	if (ret)
 		goto remove_debugfs;

 	debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
 			    &cros_ec_pdinfo_fops);

 	if (cros_ec_uptime_is_supported(ec->ec_dev))
 		debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
 				    &cros_ec_uptime_fops);

 	debugfs_create_x32("last_resume_result", 0444, debug_info->dir,
 			   &ec->ec_dev->last_resume_result);

 	debugfs_create_u16("suspend_timeout_ms", 0664, debug_info->dir,
 			   &ec->ec_dev->suspend_timeout_ms);

 	debug_info->notifier_panic.notifier_call = cros_ec_debugfs_panic_event;
 	ret = blocking_notifier_chain_register(&ec->ec_dev->panic_notifier,
 					       &debug_info->notifier_panic);
 	if (ret)
 		goto remove_debugfs;

 	ec->debug_info = debug_info;

 	dev_set_drvdata(&pd->dev, ec);

 	return 0;

 remove_debugfs:
 	debugfs_remove_recursive(debug_info->dir);
 	return ret;
 }

 static void cros_ec_debugfs_remove(struct platform_device *pd)
 {
 	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);

 	debugfs_remove_recursive(ec->debug_info->dir);
 	cros_ec_cleanup_console_log(ec->debug_info);
 }

 static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
 {
 	struct cros_ec_dev *ec = dev_get_drvdata(dev);

 	if (ec->debug_info->log_buffer.buf)
 		cancel_delayed_work_sync(&ec->debug_info->log_poll_work);

 	return 0;
 }

 static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
 {
 	struct cros_ec_dev *ec = dev_get_drvdata(dev);

 	if (ec->debug_info->log_buffer.buf)
 		schedule_delayed_work(&ec->debug_info->log_poll_work, 0);

 	return 0;
 }

 static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
 			 cros_ec_debugfs_suspend, cros_ec_debugfs_resume);

 static const struct platform_device_id cros_ec_debugfs_id[] = {
 	{ DRV_NAME, 0 },
 	{}
 };
 MODULE_DEVICE_TABLE(platform, cros_ec_debugfs_id);

 static struct platform_driver cros_ec_debugfs_driver = {
 	.driver = {
 		.name = DRV_NAME,
 		.pm = &cros_ec_debugfs_pm_ops,
 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
 	},
 	.probe = cros_ec_debugfs_probe,
 	.remove_new = cros_ec_debugfs_remove,
 	.id_table = cros_ec_debugfs_id,
 };

 module_platform_driver(cros_ec_debugfs_driver);

 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Debug logs for ChromeOS EC");
	// SPDX-License-Identifier: GPL-2.0+
	// Debug logs for the ChromeOS EC
	//
	// Copyright (C) 2015 Google, Inc.

	#include <linux/circ_buf.h>
	#include <linux/debugfs.h>
	#include <linux/delay.h>
	#include <linux/fs.h>
	#include <linux/mod_devicetable.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/platform_data/cros_ec_commands.h>
	#include <linux/platform_data/cros_ec_proto.h>
	#include <linux/platform_device.h>
	#include <linux/poll.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/wait.h>

	#define DRV_NAME "cros-ec-debugfs"

	#define LOG_SHIFT 14
	#define LOG_SIZE (1 << LOG_SHIFT)
	#define LOG_POLL_SEC 10

	#define CIRC_ADD(idx, size, value) (((idx) + (value)) & ((size) - 1))

	static unsigned int log_poll_period_ms = LOG_POLL_SEC * MSEC_PER_SEC;
	module_param(log_poll_period_ms, uint, 0644);
	MODULE_PARM_DESC(log_poll_period_ms, "EC log polling period(ms)");

	/* waitqueue for log readers */
	static DECLARE_WAIT_QUEUE_HEAD(cros_ec_debugfs_log_wq);

	/**
	* struct cros_ec_debugfs - EC debugging information.
	*
	* @ec: EC device this debugfs information belongs to
	* @dir: dentry for debugfs files
	* @log_buffer: circular buffer for console log information
	* @read_msg: preallocated EC command and buffer to read console log
	* @log_mutex: mutex to protect circular buffer
	* @log_poll_work: recurring task to poll EC for new console log data
	* @panicinfo_blob: panicinfo debugfs blob
	* @notifier_panic: notifier_block to let kernel to flush buffered log
	* when EC panic
	*/
	struct cros_ec_debugfs {
	struct cros_ec_dev *ec;
	struct dentry *dir;
	/* EC log */
	struct circ_buf log_buffer;
	struct cros_ec_command *read_msg;
	struct mutex log_mutex;
	struct delayed_work log_poll_work;
	/* EC panicinfo */
	struct debugfs_blob_wrapper panicinfo_blob;
	struct notifier_block notifier_panic;
	};

	/*
	* We need to make sure that the EC log buffer on the UART is large enough,
	* so that it is unlikely enough to overlow within log_poll_period_ms.
	*/
	static void cros_ec_console_log_work(struct work_struct *__work)
	{
	struct cros_ec_debugfs *debug_info =
	container_of(to_delayed_work(__work),
	struct cros_ec_debugfs,
	log_poll_work);
	struct cros_ec_dev *ec = debug_info->ec;
	struct circ_buf *cb = &debug_info->log_buffer;
	struct cros_ec_command snapshot_msg = {
	.command = EC_CMD_CONSOLE_SNAPSHOT + ec->cmd_offset,
	};

	struct ec_params_console_read_v1 *read_params =
	(struct ec_params_console_read_v1 *)debug_info->read_msg->data;
	uint8_t ec_buffer = (uint8_t )debug_info->read_msg->data;
	int idx;
	int buf_space;
	int ret;

	ret = cros_ec_cmd_xfer_status(ec->ec_dev, &snapshot_msg);
	if (ret < 0)
	goto resched;

	/* Loop until we have read everything, or there's an error. */
	mutex_lock(&debug_info->log_mutex);
	buf_space = CIRC_SPACE(cb->head, cb->tail, LOG_SIZE);

	while (1) {
	if (!buf_space) {
	dev_info_once(ec->dev,
	"Some logs may have been dropped...\n");
	break;
	}

	memset(read_params, '\0', sizeof(*read_params));
	read_params->subcmd = CONSOLE_READ_RECENT;
	ret = cros_ec_cmd_xfer_status(ec->ec_dev,
	debug_info->read_msg);
	if (ret < 0)
	break;

	/* If the buffer is empty, we're done here. */
	if (ret == 0 \|\| ec_buffer[0] == '\0')
	break;

	idx = 0;
	while (idx < ret && ec_buffer[idx] != '\0' && buf_space > 0) {
	cb->buf[cb->head] = ec_buffer[idx];
	cb->head = CIRC_ADD(cb->head, LOG_SIZE, 1);
	idx++;
	buf_space--;
	}

	wake_up(&cros_ec_debugfs_log_wq);
	}

	mutex_unlock(&debug_info->log_mutex);

	resched:
	schedule_delayed_work(&debug_info->log_poll_work,
	msecs_to_jiffies(log_poll_period_ms));
	}

	static int cros_ec_console_log_open(struct inode inode, struct file file)
	{
	file->private_data = inode->i_private;

	return stream_open(inode, file);
	}

	static ssize_t cros_ec_console_log_read(struct file file, char __user buf,
	size_t count, loff_t *ppos)
	{
	struct cros_ec_debugfs *debug_info = file->private_data;
	struct circ_buf *cb = &debug_info->log_buffer;
	ssize_t ret;

	mutex_lock(&debug_info->log_mutex);

	while (!CIRC_CNT(cb->head, cb->tail, LOG_SIZE)) {
	if (file->f_flags & O_NONBLOCK) {
	ret = -EAGAIN;
	goto error;
	}

	mutex_unlock(&debug_info->log_mutex);

	ret = wait_event_interruptible(cros_ec_debugfs_log_wq,
	CIRC_CNT(cb->head, cb->tail, LOG_SIZE));
	if (ret < 0)
	return ret;

	mutex_lock(&debug_info->log_mutex);
	}

	/* Only copy until the end of the circular buffer, and let userspace
	* retry to get the rest of the data.
	*/
	ret = min_t(size_t, CIRC_CNT_TO_END(cb->head, cb->tail, LOG_SIZE),
	count);

	if (copy_to_user(buf, cb->buf + cb->tail, ret)) {
	ret = -EFAULT;
	goto error;
	}

	cb->tail = CIRC_ADD(cb->tail, LOG_SIZE, ret);

	error:
	mutex_unlock(&debug_info->log_mutex);
	return ret;
	}

	static __poll_t cros_ec_console_log_poll(struct file *file,
	poll_table *wait)
	{
	struct cros_ec_debugfs *debug_info = file->private_data;
	__poll_t mask = 0;

	poll_wait(file, &cros_ec_debugfs_log_wq, wait);

	mutex_lock(&debug_info->log_mutex);
	if (CIRC_CNT(debug_info->log_buffer.head,
	debug_info->log_buffer.tail,
	LOG_SIZE))
	mask \|= EPOLLIN \| EPOLLRDNORM;
	mutex_unlock(&debug_info->log_mutex);

	return mask;
	}

	static int cros_ec_console_log_release(struct inode inode, struct file file)
	{
	return 0;
	}

	static ssize_t cros_ec_pdinfo_read(struct file *file,
	char __user *user_buf,
	size_t count,
	loff_t *ppos)
	{
	char read_buf[EC_USB_PD_MAX_PORTS * 40], *p = read_buf;
	struct cros_ec_debugfs *debug_info = file->private_data;
	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
	struct {
	struct cros_ec_command msg;
	union {
	struct ec_response_usb_pd_control_v1 resp;
	struct ec_params_usb_pd_control params;
	};
	} __packed ec_buf;
	struct cros_ec_command *msg;
	struct ec_response_usb_pd_control_v1 *resp;
	struct ec_params_usb_pd_control *params;
	int i;

	msg = &ec_buf.msg;
	params = (struct ec_params_usb_pd_control *)msg->data;
	resp = (struct ec_response_usb_pd_control_v1 *)msg->data;

	msg->command = EC_CMD_USB_PD_CONTROL;
	msg->version = 1;
	msg->insize = sizeof(*resp);
	msg->outsize = sizeof(*params);

	/*
	* Read status from all PD ports until failure, typically caused
	* by attempting to read status on a port that doesn't exist.
	*/
	for (i = 0; i < EC_USB_PD_MAX_PORTS; ++i) {
	params->port = i;
	params->role = 0;
	params->mux = 0;
	params->swap = 0;

	if (cros_ec_cmd_xfer_status(ec_dev, msg) < 0)
	break;

	p += scnprintf(p, sizeof(read_buf) + read_buf - p,
	"p%d: %s en:%.2x role:%.2x pol:%.2x\n", i,
	resp->state, resp->enabled, resp->role,
	resp->polarity);
	}

	return simple_read_from_buffer(user_buf, count, ppos,
	read_buf, p - read_buf);
	}

	static bool cros_ec_uptime_is_supported(struct cros_ec_device *ec_dev)
	{
	struct {
	struct cros_ec_command cmd;
	struct ec_response_uptime_info resp;
	} __packed msg = {};
	int ret;

	msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
	msg.cmd.insize = sizeof(msg.resp);

	ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
	if (ret == -EPROTO && msg.cmd.result == EC_RES_INVALID_COMMAND)
	return false;

	/* Other errors maybe a transient error, do not rule about support. */
	return true;
	}

	static ssize_t cros_ec_uptime_read(struct file file, char __user user_buf,
	size_t count, loff_t *ppos)
	{
	struct cros_ec_debugfs *debug_info = file->private_data;
	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
	struct {
	struct cros_ec_command cmd;
	struct ec_response_uptime_info resp;
	} __packed msg = {};
	struct ec_response_uptime_info *resp;
	char read_buf[32];
	int ret;

	resp = (struct ec_response_uptime_info *)&msg.resp;

	msg.cmd.command = EC_CMD_GET_UPTIME_INFO;
	msg.cmd.insize = sizeof(*resp);

	ret = cros_ec_cmd_xfer_status(ec_dev, &msg.cmd);
	if (ret < 0)
	return ret;

	ret = scnprintf(read_buf, sizeof(read_buf), "%u\n",
	resp->time_since_ec_boot_ms);

	return simple_read_from_buffer(user_buf, count, ppos, read_buf, ret);
	}

	static const struct file_operations cros_ec_console_log_fops = {
	.owner = THIS_MODULE,
	.open = cros_ec_console_log_open,
	.read = cros_ec_console_log_read,
	.poll = cros_ec_console_log_poll,
	.release = cros_ec_console_log_release,
	};

	static const struct file_operations cros_ec_pdinfo_fops = {
	.owner = THIS_MODULE,
	.open = simple_open,
	.read = cros_ec_pdinfo_read,
	.llseek = default_llseek,
	};

	static const struct file_operations cros_ec_uptime_fops = {
	.owner = THIS_MODULE,
	.open = simple_open,
	.read = cros_ec_uptime_read,
	.llseek = default_llseek,
	};

	static int ec_read_version_supported(struct cros_ec_dev *ec)
	{
	struct ec_params_get_cmd_versions_v1 *params;
	struct ec_response_get_cmd_versions *response;
	int ret;

	struct cros_ec_command *msg;

	msg = kzalloc(sizeof(msg) + max(sizeof(params), sizeof(*response)),
	GFP_KERNEL);
	if (!msg)
	return 0;

	msg->version = 1;
	msg->command = EC_CMD_GET_CMD_VERSIONS + ec->cmd_offset;
	msg->outsize = sizeof(*params);
	msg->insize = sizeof(*response);

	params = (struct ec_params_get_cmd_versions_v1 *)msg->data;
	params->cmd = EC_CMD_CONSOLE_READ;
	response = (struct ec_response_get_cmd_versions *)msg->data;

	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg) >= 0 &&
	response->version_mask & EC_VER_MASK(1);

	kfree(msg);

	return ret;
	}

	static int cros_ec_create_console_log(struct cros_ec_debugfs *debug_info)
	{
	struct cros_ec_dev *ec = debug_info->ec;
	char *buf;
	int read_params_size;
	int read_response_size;

	/*
	* If the console log feature is not supported return silently and
	* don't create the console_log entry.
	*/
	if (!ec_read_version_supported(ec))
	return 0;

	buf = devm_kzalloc(ec->dev, LOG_SIZE, GFP_KERNEL);
	if (!buf)
	return -ENOMEM;

	read_params_size = sizeof(struct ec_params_console_read_v1);
	read_response_size = ec->ec_dev->max_response;
	debug_info->read_msg = devm_kzalloc(ec->dev,
	sizeof(*debug_info->read_msg) +
	max(read_params_size, read_response_size), GFP_KERNEL);
	if (!debug_info->read_msg)
	return -ENOMEM;

	debug_info->read_msg->version = 1;
	debug_info->read_msg->command = EC_CMD_CONSOLE_READ + ec->cmd_offset;
	debug_info->read_msg->outsize = read_params_size;
	debug_info->read_msg->insize = read_response_size;

	debug_info->log_buffer.buf = buf;
	debug_info->log_buffer.head = 0;
	debug_info->log_buffer.tail = 0;

	mutex_init(&debug_info->log_mutex);

	debugfs_create_file("console_log", S_IFREG \| 0444, debug_info->dir,
	debug_info, &cros_ec_console_log_fops);

	INIT_DELAYED_WORK(&debug_info->log_poll_work,
	cros_ec_console_log_work);
	schedule_delayed_work(&debug_info->log_poll_work, 0);

	return 0;
	}

	static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
	{
	if (debug_info->log_buffer.buf) {
	cancel_delayed_work_sync(&debug_info->log_poll_work);
	mutex_destroy(&debug_info->log_mutex);
	}
	}

	/*
	* Returns the size of the panicinfo data fetched from the EC
	*/
	static int cros_ec_get_panicinfo(struct cros_ec_device ec_dev, uint8_t data,
	int data_size)
	{
	int ret;
	struct cros_ec_command *msg;

	if (!data \|\| data_size <= 0 \|\| data_size > ec_dev->max_response)
	return -EINVAL;

	msg = kzalloc(sizeof(*msg) + data_size, GFP_KERNEL);
	if (!msg)
	return -ENOMEM;

	msg->command = EC_CMD_GET_PANIC_INFO;
	msg->insize = data_size;

	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
	if (ret < 0)
	goto free;

	memcpy(data, msg->data, data_size);

	free:
	kfree(msg);
	return ret;
	}

	static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
	{
	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
	int ret;
	void *data;

	data = devm_kzalloc(debug_info->ec->dev, ec_dev->max_response,
	GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	ret = cros_ec_get_panicinfo(ec_dev, data, ec_dev->max_response);
	if (ret < 0) {
	ret = 0;
	goto free;
	}

	/* No panic data */
	if (ret == 0)
	goto free;

	debug_info->panicinfo_blob.data = data;
	debug_info->panicinfo_blob.size = ret;

	debugfs_create_blob("panicinfo", 0444, debug_info->dir,
	&debug_info->panicinfo_blob);

	return 0;

	free:
	devm_kfree(debug_info->ec->dev, data);
	return ret;
	}

	static int cros_ec_debugfs_panic_event(struct notifier_block *nb,
	unsigned long queued_during_suspend, void *_notify)
	{
	struct cros_ec_debugfs *debug_info =
	container_of(nb, struct cros_ec_debugfs, notifier_panic);

	if (debug_info->log_buffer.buf) {
	/* Force log poll work to run immediately */
	mod_delayed_work(debug_info->log_poll_work.wq, &debug_info->log_poll_work, 0);
	/* Block until log poll work finishes */
	flush_delayed_work(&debug_info->log_poll_work);
	}

	return NOTIFY_DONE;
	}

	static int cros_ec_debugfs_probe(struct platform_device *pd)
	{
	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
	struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
	const char *name = ec_platform->ec_name;
	struct cros_ec_debugfs *debug_info;
	int ret;

	debug_info = devm_kzalloc(ec->dev, sizeof(*debug_info), GFP_KERNEL);
	if (!debug_info)
	return -ENOMEM;

	debug_info->ec = ec;
	debug_info->dir = debugfs_create_dir(name, NULL);

	ret = cros_ec_create_panicinfo(debug_info);
	if (ret)
	goto remove_debugfs;

	ret = cros_ec_create_console_log(debug_info);
	if (ret)
	goto remove_debugfs;

	debugfs_create_file("pdinfo", 0444, debug_info->dir, debug_info,
	&cros_ec_pdinfo_fops);

	if (cros_ec_uptime_is_supported(ec->ec_dev))
	debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
	&cros_ec_uptime_fops);

	debugfs_create_x32("last_resume_result", 0444, debug_info->dir,
	&ec->ec_dev->last_resume_result);

	debugfs_create_u16("suspend_timeout_ms", 0664, debug_info->dir,
	&ec->ec_dev->suspend_timeout_ms);

	debug_info->notifier_panic.notifier_call = cros_ec_debugfs_panic_event;
	ret = blocking_notifier_chain_register(&ec->ec_dev->panic_notifier,
	&debug_info->notifier_panic);
	if (ret)
	goto remove_debugfs;

	ec->debug_info = debug_info;

	dev_set_drvdata(&pd->dev, ec);

	return 0;

	remove_debugfs:
	debugfs_remove_recursive(debug_info->dir);
	return ret;
	}

	static void cros_ec_debugfs_remove(struct platform_device *pd)
	{
	struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);

	debugfs_remove_recursive(ec->debug_info->dir);
	cros_ec_cleanup_console_log(ec->debug_info);
	}

	static int __maybe_unused cros_ec_debugfs_suspend(struct device *dev)
	{
	struct cros_ec_dev *ec = dev_get_drvdata(dev);

	if (ec->debug_info->log_buffer.buf)
	cancel_delayed_work_sync(&ec->debug_info->log_poll_work);

	return 0;
	}

	static int __maybe_unused cros_ec_debugfs_resume(struct device *dev)
	{
	struct cros_ec_dev *ec = dev_get_drvdata(dev);

	if (ec->debug_info->log_buffer.buf)
	schedule_delayed_work(&ec->debug_info->log_poll_work, 0);

	return 0;
	}

	static SIMPLE_DEV_PM_OPS(cros_ec_debugfs_pm_ops,
	cros_ec_debugfs_suspend, cros_ec_debugfs_resume);

	static const struct platform_device_id cros_ec_debugfs_id[] = {
	{ DRV_NAME, 0 },
	{}
	};
	MODULE_DEVICE_TABLE(platform, cros_ec_debugfs_id);

	static struct platform_driver cros_ec_debugfs_driver = {
	.driver = {
	.name = DRV_NAME,
	.pm = &cros_ec_debugfs_pm_ops,
	.probe_type = PROBE_PREFER_ASYNCHRONOUS,
	},
	.probe = cros_ec_debugfs_probe,
	.remove_new = cros_ec_debugfs_remove,
	.id_table = cros_ec_debugfs_id,
	};

	module_platform_driver(cros_ec_debugfs_driver);

	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("Debug logs for ChromeOS EC");