drivers/watchdog/mv64x60_wdt.c - linux/kernel/git/viro/vfs - Git at Google

 /*
  * mv64x60_wdt.c - MV64X60 (Marvell Discovery) watchdog userspace interface
  *
  * Author: James Chapman <jchapman@katalix.com>
  *
  * Platform-specific setup code should configure the dog to generate
  * interrupt or reset as required.  This code only enables/disables
  * and services the watchdog.
  *
  * Derived from mpc8xx_wdt.c, with the following copyright.
  *
  * 2002 (c) Florian Schirmer <jolt@tuxbox.org> 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/fs.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/watchdog.h>
 #include <linux/platform_device.h>
 #include <linux/mv643xx.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>

 #define MV64x60_WDT_WDC_OFFSET	0

 /*
  * The watchdog configuration register contains a pair of 2-bit fields,
  *   1.  a reload field, bits 27-26, which triggers a reload of
  *       the countdown register, and
  *   2.  an enable field, bits 25-24, which toggles between
  *       enabling and disabling the watchdog timer.
  * Bit 31 is a read-only field which indicates whether the
  * watchdog timer is currently enabled.
  *
  * The low 24 bits contain the timer reload value.
  */
 #define MV64x60_WDC_ENABLE_SHIFT	24
 #define MV64x60_WDC_SERVICE_SHIFT	26
 #define MV64x60_WDC_ENABLED_SHIFT	31

 #define MV64x60_WDC_ENABLED_TRUE	1
 #define MV64x60_WDC_ENABLED_FALSE	0

 /* Flags bits */
 #define MV64x60_WDOG_FLAG_OPENED	0

 static unsigned long wdt_flags;
 static int wdt_status;
 static void __iomem *mv64x60_wdt_regs;
 static int mv64x60_wdt_timeout;
 static int mv64x60_wdt_count;
 static unsigned int bus_clk;
 static char expect_close;
 static DEFINE_SPINLOCK(mv64x60_wdt_spinlock);

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

 static int mv64x60_wdt_toggle_wdc(int enabled_predicate, int field_shift)
 {
 	u32 data;
 	u32 enabled;
 	int ret = 0;

 	spin_lock(&mv64x60_wdt_spinlock);
 	data = readl(mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
 	enabled = (data >> MV64x60_WDC_ENABLED_SHIFT) & 1;

 	/* only toggle the requested field if enabled state matches predicate */
 	if ((enabled ^ enabled_predicate) == 0) {
 		/* We write a 1, then a 2 -- to the appropriate field */
 		data = (1 << field_shift) | mv64x60_wdt_count;
 		writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);

 		data = (2 << field_shift) | mv64x60_wdt_count;
 		writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
 		ret = 1;
 	}
 	spin_unlock(&mv64x60_wdt_spinlock);

 	return ret;
 }

 static void mv64x60_wdt_service(void)
 {
 	mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
 			       MV64x60_WDC_SERVICE_SHIFT);
 }

 static void mv64x60_wdt_handler_enable(void)
 {
 	if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_FALSE,
 				   MV64x60_WDC_ENABLE_SHIFT)) {
 		mv64x60_wdt_service();
 		printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
 	}
 }

 static void mv64x60_wdt_handler_disable(void)
 {
 	if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
 				   MV64x60_WDC_ENABLE_SHIFT))
 		printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
 }

 static void mv64x60_wdt_set_timeout(unsigned int timeout)
 {
 	/* maximum bus cycle count is 0xFFFFFFFF */
 	if (timeout > 0xFFFFFFFF / bus_clk)
 		timeout = 0xFFFFFFFF / bus_clk;

 	mv64x60_wdt_count = timeout * bus_clk >> 8;
 	mv64x60_wdt_timeout = timeout;
 }

 static int mv64x60_wdt_open(struct inode *inode, struct file *file)
 {
 	if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
 		return -EBUSY;

 	if (nowayout)
 		__module_get(THIS_MODULE);

 	mv64x60_wdt_handler_enable();

 	return nonseekable_open(inode, file);
 }

 static int mv64x60_wdt_release(struct inode *inode, struct file *file)
 {
 	if (expect_close == 42)
 		mv64x60_wdt_handler_disable();
 	else {
 		printk(KERN_CRIT
 		       "mv64x60_wdt: unexpected close, not stopping timer!\n");
 		mv64x60_wdt_service();
 	}
 	expect_close = 0;

 	clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);

 	return 0;
 }

 static ssize_t mv64x60_wdt_write(struct file *file, const char __user *data,
 				 size_t len, loff_t *ppos)
 {
 	if (len) {
 		if (!nowayout) {
 			size_t i;

 			expect_close = 0;

 			for (i = 0; i != len; i++) {
 				char c;
 				if (get_user(c, data + i))
 					return -EFAULT;
 				if (c == 'V')
 					expect_close = 42;
 			}
 		}
 		mv64x60_wdt_service();
 	}

 	return len;
 }

 static long mv64x60_wdt_ioctl(struct file *file,
 					unsigned int cmd, unsigned long arg)
 {
 	int timeout;
 	int options;
 	void __user *argp = (void __user *)arg;
 	static struct watchdog_info info = {
 		.options =	WDIOF_SETTIMEOUT	|
 				WDIOF_MAGICCLOSE	|
 				WDIOF_KEEPALIVEPING,
 		.firmware_version = 0,
 		.identity = "MV64x60 watchdog",
 	};

 	switch (cmd) {
 	case WDIOC_GETSUPPORT:
 		if (copy_to_user(argp, &info, sizeof(info)))
 			return -EFAULT;
 		break;

 	case WDIOC_GETSTATUS:
 	case WDIOC_GETBOOTSTATUS:
 		if (put_user(wdt_status, (int __user *)argp))
 			return -EFAULT;
 		wdt_status &= ~WDIOF_KEEPALIVEPING;
 		break;

 	case WDIOC_GETTEMP:
 		return -EOPNOTSUPP;

 	case WDIOC_SETOPTIONS:
 		if (get_user(options, (int __user *)argp))
 			return -EFAULT;

 		if (options & WDIOS_DISABLECARD)
 			mv64x60_wdt_handler_disable();

 		if (options & WDIOS_ENABLECARD)
 			mv64x60_wdt_handler_enable();
 		break;

 	case WDIOC_KEEPALIVE:
 		mv64x60_wdt_service();
 		wdt_status |= WDIOF_KEEPALIVEPING;
 		break;

 	case WDIOC_SETTIMEOUT:
 		if (get_user(timeout, (int __user *)argp))
 			return -EFAULT;
 		mv64x60_wdt_set_timeout(timeout);
 		/* Fall through */

 	case WDIOC_GETTIMEOUT:
 		if (put_user(mv64x60_wdt_timeout, (int __user *)argp))
 			return -EFAULT;
 		break;

 	default:
 		return -ENOTTY;
 	}

 	return 0;
 }

 static const struct file_operations mv64x60_wdt_fops = {
 	.owner = THIS_MODULE,
 	.llseek = no_llseek,
 	.write = mv64x60_wdt_write,
 	.unlocked_ioctl = mv64x60_wdt_ioctl,
 	.open = mv64x60_wdt_open,
 	.release = mv64x60_wdt_release,
 };

 static struct miscdevice mv64x60_wdt_miscdev = {
 	.minor = WATCHDOG_MINOR,
 	.name = "watchdog",
 	.fops = &mv64x60_wdt_fops,
 };

 static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
 {
 	struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data;
 	struct resource *r;
 	int timeout = 10;

 	bus_clk = 133;			/* in MHz */
 	if (pdata) {
 		timeout = pdata->timeout;
 		bus_clk = pdata->bus_clk;
 	}

 	/* Since bus_clk is truncated MHz, actual frequency could be
 	 * up to 1MHz higher.  Round up, since it's better to time out
 	 * too late than too soon.
 	 */
 	bus_clk++;
 	bus_clk *= 1000000;		/* convert to Hz */

 	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
 	if (!r)
 		return -ENODEV;

 	mv64x60_wdt_regs = ioremap(r->start, r->end - r->start + 1);
 	if (mv64x60_wdt_regs == NULL)
 		return -ENOMEM;

 	mv64x60_wdt_set_timeout(timeout);

 	mv64x60_wdt_handler_disable();	/* in case timer was already running */

 	return misc_register(&mv64x60_wdt_miscdev);
 }

 static int __devexit mv64x60_wdt_remove(struct platform_device *dev)
 {
 	misc_deregister(&mv64x60_wdt_miscdev);

 	mv64x60_wdt_handler_disable();

 	iounmap(mv64x60_wdt_regs);

 	return 0;
 }

 static struct platform_driver mv64x60_wdt_driver = {
 	.probe = mv64x60_wdt_probe,
 	.remove = __devexit_p(mv64x60_wdt_remove),
 	.driver = {
 		.owner = THIS_MODULE,
 		.name = MV64x60_WDT_NAME,
 	},
 };

 static int __init mv64x60_wdt_init(void)
 {
 	printk(KERN_INFO "MV64x60 watchdog driver\n");

 	return platform_driver_register(&mv64x60_wdt_driver);
 }

 static void __exit mv64x60_wdt_exit(void)
 {
 	platform_driver_unregister(&mv64x60_wdt_driver);
 }

 module_init(mv64x60_wdt_init);
 module_exit(mv64x60_wdt_exit);

 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 MODULE_DESCRIPTION("MV64x60 watchdog driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 MODULE_ALIAS("platform:" MV64x60_WDT_NAME);
	/*
	* mv64x60_wdt.c - MV64X60 (Marvell Discovery) watchdog userspace interface
	*
	* Author: James Chapman <jchapman@katalix.com>
	*
	* Platform-specific setup code should configure the dog to generate
	* interrupt or reset as required. This code only enables/disables
	* and services the watchdog.
	*
	* Derived from mpc8xx_wdt.c, with the following copyright.
	*
	* 2002 (c) Florian Schirmer <jolt@tuxbox.org> 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/fs.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/miscdevice.h>
	#include <linux/module.h>
	#include <linux/watchdog.h>
	#include <linux/platform_device.h>
	#include <linux/mv643xx.h>
	#include <linux/uaccess.h>
	#include <linux/io.h>

	#define MV64x60_WDT_WDC_OFFSET 0

	/*
	* The watchdog configuration register contains a pair of 2-bit fields,
	* 1. a reload field, bits 27-26, which triggers a reload of
	* the countdown register, and
	* 2. an enable field, bits 25-24, which toggles between
	* enabling and disabling the watchdog timer.
	* Bit 31 is a read-only field which indicates whether the
	* watchdog timer is currently enabled.
	*
	* The low 24 bits contain the timer reload value.
	*/
	#define MV64x60_WDC_ENABLE_SHIFT 24
	#define MV64x60_WDC_SERVICE_SHIFT 26
	#define MV64x60_WDC_ENABLED_SHIFT 31

	#define MV64x60_WDC_ENABLED_TRUE 1
	#define MV64x60_WDC_ENABLED_FALSE 0

	/* Flags bits */
	#define MV64x60_WDOG_FLAG_OPENED 0

	static unsigned long wdt_flags;
	static int wdt_status;
	static void __iomem *mv64x60_wdt_regs;
	static int mv64x60_wdt_timeout;
	static int mv64x60_wdt_count;
	static unsigned int bus_clk;
	static char expect_close;
	static DEFINE_SPINLOCK(mv64x60_wdt_spinlock);

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

	static int mv64x60_wdt_toggle_wdc(int enabled_predicate, int field_shift)
	{
	u32 data;
	u32 enabled;
	int ret = 0;

	spin_lock(&mv64x60_wdt_spinlock);
	data = readl(mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
	enabled = (data >> MV64x60_WDC_ENABLED_SHIFT) & 1;

	/* only toggle the requested field if enabled state matches predicate */
	if ((enabled ^ enabled_predicate) == 0) {
	/* We write a 1, then a 2 -- to the appropriate field */
	data = (1 << field_shift) \| mv64x60_wdt_count;
	writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);

	data = (2 << field_shift) \| mv64x60_wdt_count;
	writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
	ret = 1;
	}
	spin_unlock(&mv64x60_wdt_spinlock);

	return ret;
	}

	static void mv64x60_wdt_service(void)
	{
	mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
	MV64x60_WDC_SERVICE_SHIFT);
	}

	static void mv64x60_wdt_handler_enable(void)
	{
	if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_FALSE,
	MV64x60_WDC_ENABLE_SHIFT)) {
	mv64x60_wdt_service();
	printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
	}
	}

	static void mv64x60_wdt_handler_disable(void)
	{
	if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
	MV64x60_WDC_ENABLE_SHIFT))
	printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
	}

	static void mv64x60_wdt_set_timeout(unsigned int timeout)
	{
	/* maximum bus cycle count is 0xFFFFFFFF */
	if (timeout > 0xFFFFFFFF / bus_clk)
	timeout = 0xFFFFFFFF / bus_clk;

	mv64x60_wdt_count = timeout * bus_clk >> 8;
	mv64x60_wdt_timeout = timeout;
	}

	static int mv64x60_wdt_open(struct inode inode, struct file file)
	{
	if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
	return -EBUSY;

	if (nowayout)
	__module_get(THIS_MODULE);

	mv64x60_wdt_handler_enable();

	return nonseekable_open(inode, file);
	}

	static int mv64x60_wdt_release(struct inode inode, struct file file)
	{
	if (expect_close == 42)
	mv64x60_wdt_handler_disable();
	else {
	printk(KERN_CRIT
	"mv64x60_wdt: unexpected close, not stopping timer!\n");
	mv64x60_wdt_service();
	}
	expect_close = 0;

	clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);

	return 0;
	}

	static ssize_t mv64x60_wdt_write(struct file file, const char __user data,
	size_t len, loff_t *ppos)
	{
	if (len) {
	if (!nowayout) {
	size_t i;

	expect_close = 0;

	for (i = 0; i != len; i++) {
	char c;
	if (get_user(c, data + i))
	return -EFAULT;
	if (c == 'V')
	expect_close = 42;
	}
	}
	mv64x60_wdt_service();
	}

	return len;
	}

	static long mv64x60_wdt_ioctl(struct file *file,
	unsigned int cmd, unsigned long arg)
	{
	int timeout;
	int options;
	void __user argp = (void __user )arg;
	static struct watchdog_info info = {
	.options = WDIOF_SETTIMEOUT \|
	WDIOF_MAGICCLOSE \|
	WDIOF_KEEPALIVEPING,
	.firmware_version = 0,
	.identity = "MV64x60 watchdog",
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
	if (copy_to_user(argp, &info, sizeof(info)))
	return -EFAULT;
	break;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
	if (put_user(wdt_status, (int __user *)argp))
	return -EFAULT;
	wdt_status &= ~WDIOF_KEEPALIVEPING;
	break;

	case WDIOC_GETTEMP:
	return -EOPNOTSUPP;

	case WDIOC_SETOPTIONS:
	if (get_user(options, (int __user *)argp))
	return -EFAULT;

	if (options & WDIOS_DISABLECARD)
	mv64x60_wdt_handler_disable();

	if (options & WDIOS_ENABLECARD)
	mv64x60_wdt_handler_enable();
	break;

	case WDIOC_KEEPALIVE:
	mv64x60_wdt_service();
	wdt_status \|= WDIOF_KEEPALIVEPING;
	break;

	case WDIOC_SETTIMEOUT:
	if (get_user(timeout, (int __user *)argp))
	return -EFAULT;
	mv64x60_wdt_set_timeout(timeout);
	/* Fall through */

	case WDIOC_GETTIMEOUT:
	if (put_user(mv64x60_wdt_timeout, (int __user *)argp))
	return -EFAULT;
	break;

	default:
	return -ENOTTY;
	}

	return 0;
	}

	static const struct file_operations mv64x60_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = mv64x60_wdt_write,
	.unlocked_ioctl = mv64x60_wdt_ioctl,
	.open = mv64x60_wdt_open,
	.release = mv64x60_wdt_release,
	};

	static struct miscdevice mv64x60_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &mv64x60_wdt_fops,
	};

	static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
	{
	struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data;
	struct resource *r;
	int timeout = 10;

	bus_clk = 133; /* in MHz */
	if (pdata) {
	timeout = pdata->timeout;
	bus_clk = pdata->bus_clk;
	}

	/* Since bus_clk is truncated MHz, actual frequency could be
	* up to 1MHz higher. Round up, since it's better to time out
	* too late than too soon.
	*/
	bus_clk++;
	bus_clk = 1000000; / convert to Hz */

	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
	if (!r)
	return -ENODEV;

	mv64x60_wdt_regs = ioremap(r->start, r->end - r->start + 1);
	if (mv64x60_wdt_regs == NULL)
	return -ENOMEM;

	mv64x60_wdt_set_timeout(timeout);

	mv64x60_wdt_handler_disable(); /* in case timer was already running */

	return misc_register(&mv64x60_wdt_miscdev);
	}

	static int __devexit mv64x60_wdt_remove(struct platform_device *dev)
	{
	misc_deregister(&mv64x60_wdt_miscdev);

	mv64x60_wdt_handler_disable();

	iounmap(mv64x60_wdt_regs);

	return 0;
	}

	static struct platform_driver mv64x60_wdt_driver = {
	.probe = mv64x60_wdt_probe,
	.remove = __devexit_p(mv64x60_wdt_remove),
	.driver = {
	.owner = THIS_MODULE,
	.name = MV64x60_WDT_NAME,
	},
	};

	static int __init mv64x60_wdt_init(void)
	{
	printk(KERN_INFO "MV64x60 watchdog driver\n");

	return platform_driver_register(&mv64x60_wdt_driver);
	}

	static void __exit mv64x60_wdt_exit(void)
	{
	platform_driver_unregister(&mv64x60_wdt_driver);
	}

	module_init(mv64x60_wdt_init);
	module_exit(mv64x60_wdt_exit);

	MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
	MODULE_DESCRIPTION("MV64x60 watchdog driver");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	MODULE_ALIAS("platform:" MV64x60_WDT_NAME);