drivers/platform/olpc/olpc-ec.c - maze/linux - Git at Google

 /*
  * Generic driver for the OLPC Embedded Controller.
  *
  * Copyright (C) 2011-2012 One Laptop per Child Foundation.
  *
  * Licensed under the GPL v2 or later.
  */
 #include <linux/completion.h>
 #include <linux/debugfs.h>
 #include <linux/spinlock.h>
 #include <linux/mutex.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/workqueue.h>
 #include <linux/module.h>
 #include <linux/list.h>
 #include <linux/olpc-ec.h>
 #include <asm/olpc.h>

 struct ec_cmd_desc {
 	u8 cmd;
 	u8 *inbuf, *outbuf;
 	size_t inlen, outlen;

 	int err;
 	struct completion finished;
 	struct list_head node;

 	void *priv;
 };

 struct olpc_ec_priv {
 	struct olpc_ec_driver *drv;
 	struct work_struct worker;
 	struct mutex cmd_lock;

 	/* Pending EC commands */
 	struct list_head cmd_q;
 	spinlock_t cmd_q_lock;

 	struct dentry *dbgfs_dir;

 	/*
 	 * Running an EC command while suspending means we don't always finish
 	 * the command before the machine suspends.  This means that the EC
 	 * is expecting the command protocol to finish, but we after a period
 	 * of time (while the OS is asleep) the EC times out and restarts its
 	 * idle loop.  Meanwhile, the OS wakes up, thinks it's still in the
 	 * middle of the command protocol, starts throwing random things at
 	 * the EC... and everyone's uphappy.
 	 */
 	bool suspended;
 };

 static struct olpc_ec_driver *ec_driver;
 static struct olpc_ec_priv *ec_priv;
 static void *ec_cb_arg;

 void olpc_ec_driver_register(struct olpc_ec_driver *drv, void *arg)
 {
 	ec_driver = drv;
 	ec_cb_arg = arg;
 }
 EXPORT_SYMBOL_GPL(olpc_ec_driver_register);

 static void olpc_ec_worker(struct work_struct *w)
 {
 	struct olpc_ec_priv *ec = container_of(w, struct olpc_ec_priv, worker);
 	struct ec_cmd_desc *desc = NULL;
 	unsigned long flags;

 	/* Grab the first pending command from the queue */
 	spin_lock_irqsave(&ec->cmd_q_lock, flags);
 	if (!list_empty(&ec->cmd_q)) {
 		desc = list_first_entry(&ec->cmd_q, struct ec_cmd_desc, node);
 		list_del(&desc->node);
 	}
 	spin_unlock_irqrestore(&ec->cmd_q_lock, flags);

 	/* Do we actually have anything to do? */
 	if (!desc)
 		return;

 	/* Protect the EC hw with a mutex; only run one cmd at a time */
 	mutex_lock(&ec->cmd_lock);
 	desc->err = ec_driver->ec_cmd(desc->cmd, desc->inbuf, desc->inlen,
 			desc->outbuf, desc->outlen, ec_cb_arg);
 	mutex_unlock(&ec->cmd_lock);

 	/* Finished, wake up olpc_ec_cmd() */
 	complete(&desc->finished);

 	/* Run the worker thread again in case there are more cmds pending */
 	schedule_work(&ec->worker);
 }

 /*
  * Throw a cmd descripter onto the list.  We now have SMP OLPC machines, so
  * locking is pretty critical.
  */
 static void queue_ec_descriptor(struct ec_cmd_desc *desc,
 		struct olpc_ec_priv *ec)
 {
 	unsigned long flags;

 	INIT_LIST_HEAD(&desc->node);

 	spin_lock_irqsave(&ec->cmd_q_lock, flags);
 	list_add_tail(&desc->node, &ec->cmd_q);
 	spin_unlock_irqrestore(&ec->cmd_q_lock, flags);

 	schedule_work(&ec->worker);
 }

 int olpc_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *outbuf, size_t outlen)
 {
 	struct olpc_ec_priv *ec = ec_priv;
 	struct ec_cmd_desc desc;

 	/* Ensure a driver and ec hook have been registered */
 	if (WARN_ON(!ec_driver || !ec_driver->ec_cmd))
 		return -ENODEV;

 	if (!ec)
 		return -ENOMEM;

 	/* Suspending in the middle of a command hoses things really badly */
 	if (WARN_ON(ec->suspended))
 		return -EBUSY;

 	might_sleep();

 	desc.cmd = cmd;
 	desc.inbuf = inbuf;
 	desc.outbuf = outbuf;
 	desc.inlen = inlen;
 	desc.outlen = outlen;
 	desc.err = 0;
 	init_completion(&desc.finished);

 	queue_ec_descriptor(&desc, ec);

 	/* Timeouts must be handled in the platform-specific EC hook */
 	wait_for_completion(&desc.finished);

 	/* The worker thread dequeues the cmd; no need to do anything here */
 	return desc.err;
 }
 EXPORT_SYMBOL_GPL(olpc_ec_cmd);

 #ifdef CONFIG_DEBUG_FS

 /*
  * debugfs support for "generic commands", to allow sending
  * arbitrary EC commands from userspace.
  */

 #define EC_MAX_CMD_ARGS (5 + 1)		/* cmd byte + 5 args */
 #define EC_MAX_CMD_REPLY (8)

 static DEFINE_MUTEX(ec_dbgfs_lock);
 static unsigned char ec_dbgfs_resp[EC_MAX_CMD_REPLY];
 static unsigned int ec_dbgfs_resp_bytes;

 static ssize_t ec_dbgfs_cmd_write(struct file *file, const char __user *buf,
 		size_t size, loff_t *ppos)
 {
 	int i, m;
 	unsigned char ec_cmd[EC_MAX_CMD_ARGS];
 	unsigned int ec_cmd_int[EC_MAX_CMD_ARGS];
 	char cmdbuf[64];
 	int ec_cmd_bytes;

 	mutex_lock(&ec_dbgfs_lock);

 	size = simple_write_to_buffer(cmdbuf, sizeof(cmdbuf), ppos, buf, size);

 	m = sscanf(cmdbuf, "%x:%u %x %x %x %x %x", &ec_cmd_int[0],
 			&ec_dbgfs_resp_bytes, &ec_cmd_int[1], &ec_cmd_int[2],
 			&ec_cmd_int[3], &ec_cmd_int[4], &ec_cmd_int[5]);
 	if (m < 2 || ec_dbgfs_resp_bytes > EC_MAX_CMD_REPLY) {
 		/* reset to prevent overflow on read */
 		ec_dbgfs_resp_bytes = 0;

 		pr_debug("olpc-ec: bad ec cmd:  cmd:response-count [arg1 [arg2 ...]]\n");
 		size = -EINVAL;
 		goto out;
 	}

 	/* convert scanf'd ints to char */
 	ec_cmd_bytes = m - 2;
 	for (i = 0; i <= ec_cmd_bytes; i++)
 		ec_cmd[i] = ec_cmd_int[i];

 	pr_debug("olpc-ec: debugfs cmd 0x%02x with %d args %02x %02x %02x %02x %02x, want %d returns\n",
 			ec_cmd[0], ec_cmd_bytes, ec_cmd[1], ec_cmd[2],
 			ec_cmd[3], ec_cmd[4], ec_cmd[5], ec_dbgfs_resp_bytes);

 	olpc_ec_cmd(ec_cmd[0], (ec_cmd_bytes == 0) ? NULL : &ec_cmd[1],
 			ec_cmd_bytes, ec_dbgfs_resp, ec_dbgfs_resp_bytes);

 	pr_debug("olpc-ec: response %02x %02x %02x %02x %02x %02x %02x %02x (%d bytes expected)\n",
 			ec_dbgfs_resp[0], ec_dbgfs_resp[1], ec_dbgfs_resp[2],
 			ec_dbgfs_resp[3], ec_dbgfs_resp[4], ec_dbgfs_resp[5],
 			ec_dbgfs_resp[6], ec_dbgfs_resp[7],
 			ec_dbgfs_resp_bytes);

 out:
 	mutex_unlock(&ec_dbgfs_lock);
 	return size;
 }

 static ssize_t ec_dbgfs_cmd_read(struct file *file, char __user *buf,
 		size_t size, loff_t *ppos)
 {
 	unsigned int i, r;
 	char *rp;
 	char respbuf[64];

 	mutex_lock(&ec_dbgfs_lock);
 	rp = respbuf;
 	rp += sprintf(rp, "%02x", ec_dbgfs_resp[0]);
 	for (i = 1; i < ec_dbgfs_resp_bytes; i++)
 		rp += sprintf(rp, ", %02x", ec_dbgfs_resp[i]);
 	mutex_unlock(&ec_dbgfs_lock);
 	rp += sprintf(rp, "\n");

 	r = rp - respbuf;
 	return simple_read_from_buffer(buf, size, ppos, respbuf, r);
 }

 static const struct file_operations ec_dbgfs_ops = {
 	.write = ec_dbgfs_cmd_write,
 	.read = ec_dbgfs_cmd_read,
 };

 static struct dentry *olpc_ec_setup_debugfs(void)
 {
 	struct dentry *dbgfs_dir;

 	dbgfs_dir = debugfs_create_dir("olpc-ec", NULL);
 	if (IS_ERR_OR_NULL(dbgfs_dir))
 		return NULL;

 	debugfs_create_file("cmd", 0600, dbgfs_dir, NULL, &ec_dbgfs_ops);

 	return dbgfs_dir;
 }

 #else

 static struct dentry *olpc_ec_setup_debugfs(void)
 {
 	return NULL;
 }

 #endif /* CONFIG_DEBUG_FS */

 static int olpc_ec_probe(struct platform_device *pdev)
 {
 	struct olpc_ec_priv *ec;
 	int err;

 	if (!ec_driver)
 		return -ENODEV;

 	ec = kzalloc(sizeof(*ec), GFP_KERNEL);
 	if (!ec)
 		return -ENOMEM;

 	ec->drv = ec_driver;
 	INIT_WORK(&ec->worker, olpc_ec_worker);
 	mutex_init(&ec->cmd_lock);

 	INIT_LIST_HEAD(&ec->cmd_q);
 	spin_lock_init(&ec->cmd_q_lock);

 	ec_priv = ec;
 	platform_set_drvdata(pdev, ec);

 	err = ec_driver->probe ? ec_driver->probe(pdev) : 0;
 	if (err) {
 		ec_priv = NULL;
 		kfree(ec);
 	} else {
 		ec->dbgfs_dir = olpc_ec_setup_debugfs();
 	}

 	return err;
 }

 static int olpc_ec_suspend(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct olpc_ec_priv *ec = platform_get_drvdata(pdev);
 	int err = 0;

 	if (ec_driver->suspend)
 		err = ec_driver->suspend(pdev);
 	if (!err)
 		ec->suspended = true;

 	return err;
 }

 static int olpc_ec_resume(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct olpc_ec_priv *ec = platform_get_drvdata(pdev);

 	ec->suspended = false;
 	return ec_driver->resume ? ec_driver->resume(pdev) : 0;
 }

 static const struct dev_pm_ops olpc_ec_pm_ops = {
 	.suspend_late = olpc_ec_suspend,
 	.resume_early = olpc_ec_resume,
 };

 static struct platform_driver olpc_ec_plat_driver = {
 	.probe = olpc_ec_probe,
 	.driver = {
 		.name = "olpc-ec",
 		.pm = &olpc_ec_pm_ops,
 	},
 };

 static int __init olpc_ec_init_module(void)
 {
 	return platform_driver_register(&olpc_ec_plat_driver);
 }

 module_init(olpc_ec_init_module);

 MODULE_AUTHOR("Andres Salomon <dilinger@queued.net>");
 MODULE_LICENSE("GPL");
	/*
	* Generic driver for the OLPC Embedded Controller.
	*
	* Copyright (C) 2011-2012 One Laptop per Child Foundation.
	*
	* Licensed under the GPL v2 or later.
	*/
	#include <linux/completion.h>
	#include <linux/debugfs.h>
	#include <linux/spinlock.h>
	#include <linux/mutex.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>
	#include <linux/workqueue.h>
	#include <linux/module.h>
	#include <linux/list.h>
	#include <linux/olpc-ec.h>
	#include <asm/olpc.h>

	struct ec_cmd_desc {
	u8 cmd;
	u8 inbuf, outbuf;
	size_t inlen, outlen;

	int err;
	struct completion finished;
	struct list_head node;

	void *priv;
	};

	struct olpc_ec_priv {
	struct olpc_ec_driver *drv;
	struct work_struct worker;
	struct mutex cmd_lock;

	/* Pending EC commands */
	struct list_head cmd_q;
	spinlock_t cmd_q_lock;

	struct dentry *dbgfs_dir;

	/*
	* Running an EC command while suspending means we don't always finish
	* the command before the machine suspends. This means that the EC
	* is expecting the command protocol to finish, but we after a period
	* of time (while the OS is asleep) the EC times out and restarts its
	* idle loop. Meanwhile, the OS wakes up, thinks it's still in the
	* middle of the command protocol, starts throwing random things at
	* the EC... and everyone's uphappy.
	*/
	bool suspended;
	};

	static struct olpc_ec_driver *ec_driver;
	static struct olpc_ec_priv *ec_priv;
	static void *ec_cb_arg;

	void olpc_ec_driver_register(struct olpc_ec_driver drv, void arg)
	{
	ec_driver = drv;
	ec_cb_arg = arg;
	}
	EXPORT_SYMBOL_GPL(olpc_ec_driver_register);

	static void olpc_ec_worker(struct work_struct *w)
	{
	struct olpc_ec_priv *ec = container_of(w, struct olpc_ec_priv, worker);
	struct ec_cmd_desc *desc = NULL;
	unsigned long flags;

	/* Grab the first pending command from the queue */
	spin_lock_irqsave(&ec->cmd_q_lock, flags);
	if (!list_empty(&ec->cmd_q)) {
	desc = list_first_entry(&ec->cmd_q, struct ec_cmd_desc, node);
	list_del(&desc->node);
	}
	spin_unlock_irqrestore(&ec->cmd_q_lock, flags);

	/* Do we actually have anything to do? */
	if (!desc)
	return;

	/* Protect the EC hw with a mutex; only run one cmd at a time */
	mutex_lock(&ec->cmd_lock);
	desc->err = ec_driver->ec_cmd(desc->cmd, desc->inbuf, desc->inlen,
	desc->outbuf, desc->outlen, ec_cb_arg);
	mutex_unlock(&ec->cmd_lock);

	/* Finished, wake up olpc_ec_cmd() */
	complete(&desc->finished);

	/* Run the worker thread again in case there are more cmds pending */
	schedule_work(&ec->worker);
	}

	/*
	* Throw a cmd descripter onto the list. We now have SMP OLPC machines, so
	* locking is pretty critical.
	*/
	static void queue_ec_descriptor(struct ec_cmd_desc *desc,
	struct olpc_ec_priv *ec)
	{
	unsigned long flags;

	INIT_LIST_HEAD(&desc->node);

	spin_lock_irqsave(&ec->cmd_q_lock, flags);
	list_add_tail(&desc->node, &ec->cmd_q);
	spin_unlock_irqrestore(&ec->cmd_q_lock, flags);

	schedule_work(&ec->worker);
	}

	int olpc_ec_cmd(u8 cmd, u8 inbuf, size_t inlen, u8 outbuf, size_t outlen)
	{
	struct olpc_ec_priv *ec = ec_priv;
	struct ec_cmd_desc desc;

	/* Ensure a driver and ec hook have been registered */
	if (WARN_ON(!ec_driver \|\| !ec_driver->ec_cmd))
	return -ENODEV;

	if (!ec)
	return -ENOMEM;

	/* Suspending in the middle of a command hoses things really badly */
	if (WARN_ON(ec->suspended))
	return -EBUSY;

	might_sleep();

	desc.cmd = cmd;
	desc.inbuf = inbuf;
	desc.outbuf = outbuf;
	desc.inlen = inlen;
	desc.outlen = outlen;
	desc.err = 0;
	init_completion(&desc.finished);

	queue_ec_descriptor(&desc, ec);

	/* Timeouts must be handled in the platform-specific EC hook */
	wait_for_completion(&desc.finished);

	/* The worker thread dequeues the cmd; no need to do anything here */
	return desc.err;
	}
	EXPORT_SYMBOL_GPL(olpc_ec_cmd);

	#ifdef CONFIG_DEBUG_FS

	/*
	* debugfs support for "generic commands", to allow sending
	* arbitrary EC commands from userspace.
	*/

	#define EC_MAX_CMD_ARGS (5 + 1) /* cmd byte + 5 args */
	#define EC_MAX_CMD_REPLY (8)

	static DEFINE_MUTEX(ec_dbgfs_lock);
	static unsigned char ec_dbgfs_resp[EC_MAX_CMD_REPLY];
	static unsigned int ec_dbgfs_resp_bytes;

	static ssize_t ec_dbgfs_cmd_write(struct file file, const char __user buf,
	size_t size, loff_t *ppos)
	{
	int i, m;
	unsigned char ec_cmd[EC_MAX_CMD_ARGS];
	unsigned int ec_cmd_int[EC_MAX_CMD_ARGS];
	char cmdbuf[64];
	int ec_cmd_bytes;

	mutex_lock(&ec_dbgfs_lock);

	size = simple_write_to_buffer(cmdbuf, sizeof(cmdbuf), ppos, buf, size);

	m = sscanf(cmdbuf, "%x:%u %x %x %x %x %x", &ec_cmd_int[0],
	&ec_dbgfs_resp_bytes, &ec_cmd_int[1], &ec_cmd_int[2],
	&ec_cmd_int[3], &ec_cmd_int[4], &ec_cmd_int[5]);
	if (m < 2 \|\| ec_dbgfs_resp_bytes > EC_MAX_CMD_REPLY) {
	/* reset to prevent overflow on read */
	ec_dbgfs_resp_bytes = 0;

	pr_debug("olpc-ec: bad ec cmd: cmd:response-count [arg1 [arg2 ...]]\n");
	size = -EINVAL;
	goto out;
	}

	/* convert scanf'd ints to char */
	ec_cmd_bytes = m - 2;
	for (i = 0; i <= ec_cmd_bytes; i++)
	ec_cmd[i] = ec_cmd_int[i];

	pr_debug("olpc-ec: debugfs cmd 0x%02x with %d args %02x %02x %02x %02x %02x, want %d returns\n",
	ec_cmd[0], ec_cmd_bytes, ec_cmd[1], ec_cmd[2],
	ec_cmd[3], ec_cmd[4], ec_cmd[5], ec_dbgfs_resp_bytes);

	olpc_ec_cmd(ec_cmd[0], (ec_cmd_bytes == 0) ? NULL : &ec_cmd[1],
	ec_cmd_bytes, ec_dbgfs_resp, ec_dbgfs_resp_bytes);

	pr_debug("olpc-ec: response %02x %02x %02x %02x %02x %02x %02x %02x (%d bytes expected)\n",
	ec_dbgfs_resp[0], ec_dbgfs_resp[1], ec_dbgfs_resp[2],
	ec_dbgfs_resp[3], ec_dbgfs_resp[4], ec_dbgfs_resp[5],
	ec_dbgfs_resp[6], ec_dbgfs_resp[7],
	ec_dbgfs_resp_bytes);

	out:
	mutex_unlock(&ec_dbgfs_lock);
	return size;
	}

	static ssize_t ec_dbgfs_cmd_read(struct file file, char __user buf,
	size_t size, loff_t *ppos)
	{
	unsigned int i, r;
	char *rp;
	char respbuf[64];

	mutex_lock(&ec_dbgfs_lock);
	rp = respbuf;
	rp += sprintf(rp, "%02x", ec_dbgfs_resp[0]);
	for (i = 1; i < ec_dbgfs_resp_bytes; i++)
	rp += sprintf(rp, ", %02x", ec_dbgfs_resp[i]);
	mutex_unlock(&ec_dbgfs_lock);
	rp += sprintf(rp, "\n");

	r = rp - respbuf;
	return simple_read_from_buffer(buf, size, ppos, respbuf, r);
	}

	static const struct file_operations ec_dbgfs_ops = {
	.write = ec_dbgfs_cmd_write,
	.read = ec_dbgfs_cmd_read,
	};

	static struct dentry *olpc_ec_setup_debugfs(void)
	{
	struct dentry *dbgfs_dir;

	dbgfs_dir = debugfs_create_dir("olpc-ec", NULL);
	if (IS_ERR_OR_NULL(dbgfs_dir))
	return NULL;

	debugfs_create_file("cmd", 0600, dbgfs_dir, NULL, &ec_dbgfs_ops);

	return dbgfs_dir;
	}

	#else

	static struct dentry *olpc_ec_setup_debugfs(void)
	{
	return NULL;
	}

	#endif /* CONFIG_DEBUG_FS */

	static int olpc_ec_probe(struct platform_device *pdev)
	{
	struct olpc_ec_priv *ec;
	int err;

	if (!ec_driver)
	return -ENODEV;

	ec = kzalloc(sizeof(*ec), GFP_KERNEL);
	if (!ec)
	return -ENOMEM;

	ec->drv = ec_driver;
	INIT_WORK(&ec->worker, olpc_ec_worker);
	mutex_init(&ec->cmd_lock);

	INIT_LIST_HEAD(&ec->cmd_q);
	spin_lock_init(&ec->cmd_q_lock);

	ec_priv = ec;
	platform_set_drvdata(pdev, ec);

	err = ec_driver->probe ? ec_driver->probe(pdev) : 0;
	if (err) {
	ec_priv = NULL;
	kfree(ec);
	} else {
	ec->dbgfs_dir = olpc_ec_setup_debugfs();
	}

	return err;
	}

	static int olpc_ec_suspend(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct olpc_ec_priv *ec = platform_get_drvdata(pdev);
	int err = 0;

	if (ec_driver->suspend)
	err = ec_driver->suspend(pdev);
	if (!err)
	ec->suspended = true;

	return err;
	}

	static int olpc_ec_resume(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct olpc_ec_priv *ec = platform_get_drvdata(pdev);

	ec->suspended = false;
	return ec_driver->resume ? ec_driver->resume(pdev) : 0;
	}

	static const struct dev_pm_ops olpc_ec_pm_ops = {
	.suspend_late = olpc_ec_suspend,
	.resume_early = olpc_ec_resume,
	};

	static struct platform_driver olpc_ec_plat_driver = {
	.probe = olpc_ec_probe,
	.driver = {
	.name = "olpc-ec",
	.pm = &olpc_ec_pm_ops,
	},
	};

	static int __init olpc_ec_init_module(void)
	{
	return platform_driver_register(&olpc_ec_plat_driver);
	}

	module_init(olpc_ec_init_module);

	MODULE_AUTHOR("Andres Salomon <dilinger@queued.net>");
	MODULE_LICENSE("GPL");