drivers/watchdog/orion_wdt.c - kernel/skids - Git at Google

 /*
  * drivers/watchdog/orion_wdt.c
  *
  * Watchdog driver for Orion/Kirkwood processors
  *
  * Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
  *
  * This file is licensed under  the terms of the GNU General Public
  * License version 2. This program is licensed "as is" without any
  * warranty of any kind, whether express or implied.
  */

 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/fs.h>
 #include <linux/miscdevice.h>
 #include <linux/platform_device.h>
 #include <linux/watchdog.h>
 #include <linux/init.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/spinlock.h>
 #include <mach/bridge-regs.h>
 #include <plat/orion_wdt.h>

 /*
  * Watchdog timer block registers.
  */
 #define TIMER_CTRL		(TIMER_VIRT_BASE + 0x0000)
 #define  WDT_EN			0x0010
 #define WDT_VAL			(TIMER_VIRT_BASE + 0x0024)

 #define WDT_MAX_CYCLE_COUNT	0xffffffff
 #define WDT_IN_USE		0
 #define WDT_OK_TO_CLOSE		1

 static int nowayout = WATCHDOG_NOWAYOUT;
 static int heartbeat = -1;		/* module parameter (seconds) */
 static unsigned int wdt_max_duration;	/* (seconds) */
 static unsigned int wdt_tclk;
 static unsigned long wdt_status;
 static spinlock_t wdt_lock;

 static void orion_wdt_ping(void)
 {
 	spin_lock(&wdt_lock);

 	/* Reload watchdog duration */
 	writel(wdt_tclk * heartbeat, WDT_VAL);

 	spin_unlock(&wdt_lock);
 }

 static void orion_wdt_enable(void)
 {
 	u32 reg;

 	spin_lock(&wdt_lock);

 	/* Set watchdog duration */
 	writel(wdt_tclk * heartbeat, WDT_VAL);

 	/* Clear watchdog timer interrupt */
 	reg = readl(BRIDGE_CAUSE);
 	reg &= ~WDT_INT_REQ;
 	writel(reg, BRIDGE_CAUSE);

 	/* Enable watchdog timer */
 	reg = readl(TIMER_CTRL);
 	reg |= WDT_EN;
 	writel(reg, TIMER_CTRL);

 	/* Enable reset on watchdog */
 	reg = readl(RSTOUTn_MASK);
 	reg |= WDT_RESET_OUT_EN;
 	writel(reg, RSTOUTn_MASK);

 	spin_unlock(&wdt_lock);
 }

 static void orion_wdt_disable(void)
 {
 	u32 reg;

 	spin_lock(&wdt_lock);

 	/* Disable reset on watchdog */
 	reg = readl(RSTOUTn_MASK);
 	reg &= ~WDT_RESET_OUT_EN;
 	writel(reg, RSTOUTn_MASK);

 	/* Disable watchdog timer */
 	reg = readl(TIMER_CTRL);
 	reg &= ~WDT_EN;
 	writel(reg, TIMER_CTRL);

 	spin_unlock(&wdt_lock);
 }

 static int orion_wdt_get_timeleft(int *time_left)
 {
 	spin_lock(&wdt_lock);
 	*time_left = readl(WDT_VAL) / wdt_tclk;
 	spin_unlock(&wdt_lock);
 	return 0;
 }

 static int orion_wdt_open(struct inode *inode, struct file *file)
 {
 	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
 		return -EBUSY;
 	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 	orion_wdt_enable();
 	return nonseekable_open(inode, file);
 }

 static ssize_t orion_wdt_write(struct file *file, const char *data,
 					size_t len, loff_t *ppos)
 {
 	if (len) {
 		if (!nowayout) {
 			size_t i;

 			clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 			for (i = 0; i != len; i++) {
 				char c;

 				if (get_user(c, data + i))
 					return -EFAULT;
 				if (c == 'V')
 					set_bit(WDT_OK_TO_CLOSE, &wdt_status);
 			}
 		}
 		orion_wdt_ping();
 	}
 	return len;
 }

 static int orion_wdt_settimeout(int new_time)
 {
 	if ((new_time <= 0) || (new_time > wdt_max_duration))
 		return -EINVAL;

 	/* Set new watchdog time to be used when
 	 * orion_wdt_enable() or orion_wdt_ping() is called. */
 	heartbeat = new_time;
 	return 0;
 }

 static const struct watchdog_info ident = {
 	.options	= WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
 			  WDIOF_KEEPALIVEPING,
 	.identity	= "Orion Watchdog",
 };

 static long orion_wdt_ioctl(struct file *file, unsigned int cmd,
 				unsigned long arg)
 {
 	int ret = -ENOTTY;
 	int time;

 	switch (cmd) {
 	case WDIOC_GETSUPPORT:
 		ret = copy_to_user((struct watchdog_info *)arg, &ident,
 				   sizeof(ident)) ? -EFAULT : 0;
 		break;

 	case WDIOC_GETSTATUS:
 	case WDIOC_GETBOOTSTATUS:
 		ret = put_user(0, (int *)arg);
 		break;

 	case WDIOC_KEEPALIVE:
 		orion_wdt_ping();
 		ret = 0;
 		break;

 	case WDIOC_SETTIMEOUT:
 		ret = get_user(time, (int *)arg);
 		if (ret)
 			break;

 		if (orion_wdt_settimeout(time)) {
 			ret = -EINVAL;
 			break;
 		}
 		orion_wdt_ping();
 		/* Fall through */

 	case WDIOC_GETTIMEOUT:
 		ret = put_user(heartbeat, (int *)arg);
 		break;

 	case WDIOC_GETTIMELEFT:
 		if (orion_wdt_get_timeleft(&time)) {
 			ret = -EINVAL;
 			break;
 		}
 		ret = put_user(time, (int *)arg);
 		break;
 	}
 	return ret;
 }

 static int orion_wdt_release(struct inode *inode, struct file *file)
 {
 	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
 		orion_wdt_disable();
 	else
 		printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
 					"timer will not stop\n");
 	clear_bit(WDT_IN_USE, &wdt_status);
 	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

 	return 0;
 }


 static const struct file_operations orion_wdt_fops = {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
 	.write		= orion_wdt_write,
 	.unlocked_ioctl	= orion_wdt_ioctl,
 	.open		= orion_wdt_open,
 	.release	= orion_wdt_release,
 };

 static struct miscdevice orion_wdt_miscdev = {
 	.minor		= WATCHDOG_MINOR,
 	.name		= "watchdog",
 	.fops		= &orion_wdt_fops,
 };

 static int __devinit orion_wdt_probe(struct platform_device *pdev)
 {
 	struct orion_wdt_platform_data *pdata = pdev->dev.platform_data;
 	int ret;

 	if (pdata) {
 		wdt_tclk = pdata->tclk;
 	} else {
 		printk(KERN_ERR "Orion Watchdog misses platform data\n");
 		return -ENODEV;
 	}

 	if (orion_wdt_miscdev.parent)
 		return -EBUSY;
 	orion_wdt_miscdev.parent = &pdev->dev;

 	wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;
 	if (orion_wdt_settimeout(heartbeat))
 		heartbeat = wdt_max_duration;

 	ret = misc_register(&orion_wdt_miscdev);
 	if (ret)
 		return ret;

 	printk(KERN_INFO "Orion Watchdog Timer: Initial timeout %d sec%s\n",
 				heartbeat, nowayout ? ", nowayout" : "");
 	return 0;
 }

 static int __devexit orion_wdt_remove(struct platform_device *pdev)
 {
 	int ret;

 	if (test_bit(WDT_IN_USE, &wdt_status)) {
 		orion_wdt_disable();
 		clear_bit(WDT_IN_USE, &wdt_status);
 	}

 	ret = misc_deregister(&orion_wdt_miscdev);
 	if (!ret)
 		orion_wdt_miscdev.parent = NULL;

 	return ret;
 }

 static void orion_wdt_shutdown(struct platform_device *pdev)
 {
 	if (test_bit(WDT_IN_USE, &wdt_status))
 		orion_wdt_disable();
 }

 static struct platform_driver orion_wdt_driver = {
 	.probe		= orion_wdt_probe,
 	.remove		= __devexit_p(orion_wdt_remove),
 	.shutdown	= orion_wdt_shutdown,
 	.driver		= {
 		.owner	= THIS_MODULE,
 		.name	= "orion_wdt",
 	},
 };

 static int __init orion_wdt_init(void)
 {
 	spin_lock_init(&wdt_lock);
 	return platform_driver_register(&orion_wdt_driver);
 }

 static void __exit orion_wdt_exit(void)
 {
 	platform_driver_unregister(&orion_wdt_driver);
 }

 module_init(orion_wdt_init);
 module_exit(orion_wdt_exit);

 MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
 MODULE_DESCRIPTION("Orion Processor Watchdog");

 module_param(heartbeat, int, 0);
 MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");

 module_param(nowayout, int, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

 MODULE_LICENSE("GPL");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	/*
	* drivers/watchdog/orion_wdt.c
	*
	* Watchdog driver for Orion/Kirkwood processors
	*
	* Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
	*
	* This file is licensed under the terms of the GNU General Public
	* License version 2. This program is licensed "as is" without any
	* warranty of any kind, whether express or implied.
	*/

	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/fs.h>
	#include <linux/miscdevice.h>
	#include <linux/platform_device.h>
	#include <linux/watchdog.h>
	#include <linux/init.h>
	#include <linux/uaccess.h>
	#include <linux/io.h>
	#include <linux/spinlock.h>
	#include <mach/bridge-regs.h>
	#include <plat/orion_wdt.h>

	/*
	* Watchdog timer block registers.
	*/
	#define TIMER_CTRL (TIMER_VIRT_BASE + 0x0000)
	#define WDT_EN 0x0010
	#define WDT_VAL (TIMER_VIRT_BASE + 0x0024)

	#define WDT_MAX_CYCLE_COUNT 0xffffffff
	#define WDT_IN_USE 0
	#define WDT_OK_TO_CLOSE 1

	static int nowayout = WATCHDOG_NOWAYOUT;
	static int heartbeat = -1; /* module parameter (seconds) */
	static unsigned int wdt_max_duration; /* (seconds) */
	static unsigned int wdt_tclk;
	static unsigned long wdt_status;
	static spinlock_t wdt_lock;

	static void orion_wdt_ping(void)
	{
	spin_lock(&wdt_lock);

	/* Reload watchdog duration */
	writel(wdt_tclk * heartbeat, WDT_VAL);

	spin_unlock(&wdt_lock);
	}

	static void orion_wdt_enable(void)
	{
	u32 reg;

	spin_lock(&wdt_lock);

	/* Set watchdog duration */
	writel(wdt_tclk * heartbeat, WDT_VAL);

	/* Clear watchdog timer interrupt */
	reg = readl(BRIDGE_CAUSE);
	reg &= ~WDT_INT_REQ;
	writel(reg, BRIDGE_CAUSE);

	/* Enable watchdog timer */
	reg = readl(TIMER_CTRL);
	reg \|= WDT_EN;
	writel(reg, TIMER_CTRL);

	/* Enable reset on watchdog */
	reg = readl(RSTOUTn_MASK);
	reg \|= WDT_RESET_OUT_EN;
	writel(reg, RSTOUTn_MASK);

	spin_unlock(&wdt_lock);
	}

	static void orion_wdt_disable(void)
	{
	u32 reg;

	spin_lock(&wdt_lock);

	/* Disable reset on watchdog */
	reg = readl(RSTOUTn_MASK);
	reg &= ~WDT_RESET_OUT_EN;
	writel(reg, RSTOUTn_MASK);

	/* Disable watchdog timer */
	reg = readl(TIMER_CTRL);
	reg &= ~WDT_EN;
	writel(reg, TIMER_CTRL);

	spin_unlock(&wdt_lock);
	}

	static int orion_wdt_get_timeleft(int *time_left)
	{
	spin_lock(&wdt_lock);
	*time_left = readl(WDT_VAL) / wdt_tclk;
	spin_unlock(&wdt_lock);
	return 0;
	}

	static int orion_wdt_open(struct inode inode, struct file file)
	{
	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	return -EBUSY;
	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	orion_wdt_enable();
	return nonseekable_open(inode, file);
	}

	static ssize_t orion_wdt_write(struct file file, const char data,
	size_t len, loff_t *ppos)
	{
	if (len) {
	if (!nowayout) {
	size_t i;

	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	for (i = 0; i != len; i++) {
	char c;

	if (get_user(c, data + i))
	return -EFAULT;
	if (c == 'V')
	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	}
	}
	orion_wdt_ping();
	}
	return len;
	}

	static int orion_wdt_settimeout(int new_time)
	{
	if ((new_time <= 0) \|\| (new_time > wdt_max_duration))
	return -EINVAL;

	/* Set new watchdog time to be used when
	* orion_wdt_enable() or orion_wdt_ping() is called. */
	heartbeat = new_time;
	return 0;
	}

	static const struct watchdog_info ident = {
	.options = WDIOF_MAGICCLOSE \| WDIOF_SETTIMEOUT \|
	WDIOF_KEEPALIVEPING,
	.identity = "Orion Watchdog",
	};

	static long orion_wdt_ioctl(struct file *file, unsigned int cmd,
	unsigned long arg)
	{
	int ret = -ENOTTY;
	int time;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	sizeof(ident)) ? -EFAULT : 0;
	break;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
	ret = put_user(0, (int *)arg);
	break;

	case WDIOC_KEEPALIVE:
	orion_wdt_ping();
	ret = 0;
	break;

	case WDIOC_SETTIMEOUT:
	ret = get_user(time, (int *)arg);
	if (ret)
	break;

	if (orion_wdt_settimeout(time)) {
	ret = -EINVAL;
	break;
	}
	orion_wdt_ping();
	/* Fall through */

	case WDIOC_GETTIMEOUT:
	ret = put_user(heartbeat, (int *)arg);
	break;

	case WDIOC_GETTIMELEFT:
	if (orion_wdt_get_timeleft(&time)) {
	ret = -EINVAL;
	break;
	}
	ret = put_user(time, (int *)arg);
	break;
	}
	return ret;
	}

	static int orion_wdt_release(struct inode inode, struct file file)
	{
	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
	orion_wdt_disable();
	else
	printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
	"timer will not stop\n");
	clear_bit(WDT_IN_USE, &wdt_status);
	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

	return 0;
	}


	static const struct file_operations orion_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = orion_wdt_write,
	.unlocked_ioctl = orion_wdt_ioctl,
	.open = orion_wdt_open,
	.release = orion_wdt_release,
	};

	static struct miscdevice orion_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &orion_wdt_fops,
	};

	static int __devinit orion_wdt_probe(struct platform_device *pdev)
	{
	struct orion_wdt_platform_data *pdata = pdev->dev.platform_data;
	int ret;

	if (pdata) {
	wdt_tclk = pdata->tclk;
	} else {
	printk(KERN_ERR "Orion Watchdog misses platform data\n");
	return -ENODEV;
	}

	if (orion_wdt_miscdev.parent)
	return -EBUSY;
	orion_wdt_miscdev.parent = &pdev->dev;

	wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;
	if (orion_wdt_settimeout(heartbeat))
	heartbeat = wdt_max_duration;

	ret = misc_register(&orion_wdt_miscdev);
	if (ret)
	return ret;

	printk(KERN_INFO "Orion Watchdog Timer: Initial timeout %d sec%s\n",
	heartbeat, nowayout ? ", nowayout" : "");
	return 0;
	}

	static int __devexit orion_wdt_remove(struct platform_device *pdev)
	{
	int ret;

	if (test_bit(WDT_IN_USE, &wdt_status)) {
	orion_wdt_disable();
	clear_bit(WDT_IN_USE, &wdt_status);
	}

	ret = misc_deregister(&orion_wdt_miscdev);
	if (!ret)
	orion_wdt_miscdev.parent = NULL;

	return ret;
	}

	static void orion_wdt_shutdown(struct platform_device *pdev)
	{
	if (test_bit(WDT_IN_USE, &wdt_status))
	orion_wdt_disable();
	}

	static struct platform_driver orion_wdt_driver = {
	.probe = orion_wdt_probe,
	.remove = __devexit_p(orion_wdt_remove),
	.shutdown = orion_wdt_shutdown,
	.driver = {
	.owner = THIS_MODULE,
	.name = "orion_wdt",
	},
	};

	static int __init orion_wdt_init(void)
	{
	spin_lock_init(&wdt_lock);
	return platform_driver_register(&orion_wdt_driver);
	}

	static void __exit orion_wdt_exit(void)
	{
	platform_driver_unregister(&orion_wdt_driver);
	}

	module_init(orion_wdt_init);
	module_exit(orion_wdt_exit);

	MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
	MODULE_DESCRIPTION("Orion Processor Watchdog");

	module_param(heartbeat, int, 0);
	MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");

	module_param(nowayout, int, 0);
	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

	MODULE_LICENSE("GPL");
	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);