drivers/watchdog/geodewdt.c - linux - Git at Google

 /* Watchdog timer for the Geode GX/LX with the CS5535/CS5536 companion chip
  *
  * Copyright (C) 2006-2007, Advanced Micro Devices, Inc.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */


 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/types.h>
 #include <linux/miscdevice.h>
 #include <linux/watchdog.h>
 #include <linux/fs.h>
 #include <linux/platform_device.h>
 #include <linux/reboot.h>

 #include <asm/uaccess.h>
 #include <asm/geode.h>

 #define GEODEWDT_HZ 500
 #define GEODEWDT_SCALE 6
 #define GEODEWDT_MAX_SECONDS 131

 #define WDT_FLAGS_OPEN 1
 #define WDT_FLAGS_ORPHAN 2

 #define DRV_NAME "geodewdt"
 #define WATCHDOG_NAME "Geode GX/LX WDT"
 #define WATCHDOG_TIMEOUT 60

 static int timeout = WATCHDOG_TIMEOUT;
 module_param(timeout, int, 0);
 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=131, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");

 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 struct platform_device *geodewdt_platform_device;
 static unsigned long wdt_flags;
 static int wdt_timer;
 static int safe_close;

 static void geodewdt_ping(void)
 {
 	/* Stop the counter */
 	geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);

 	/* Reset the counter */
 	geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);

 	/* Enable the counter */
 	geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
 }

 static void geodewdt_disable(void)
 {
 	geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
 	geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
 }

 static int geodewdt_set_heartbeat(int val)
 {
 	if (val < 1 || val > GEODEWDT_MAX_SECONDS)
 		return -EINVAL;

 	geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
 	geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ);
 	geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
 	geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);

 	timeout = val;
 	return 0;
 }

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

         if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
                 __module_get(THIS_MODULE);

 	geodewdt_ping();
         return nonseekable_open(inode, file);
 }

 static int
 geodewdt_release(struct inode *inode, struct file *file)
 {
 	if (safe_close) {
 		geodewdt_disable();
 		module_put(THIS_MODULE);
 	}
 	else {
 		printk(KERN_CRIT "Unexpected close - watchdog is not stopping.\n");
 		geodewdt_ping();

 		set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
 	}

 	clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
 	safe_close = 0;
 	return 0;
 }

 static ssize_t
 geodewdt_write(struct file *file, const char __user *data, size_t len,
 	       loff_t *ppos)
 {
         if(len) {
 		if (!nowayout) {
 			size_t i;
 			safe_close = 0;

 			for (i = 0; i != len; i++) {
 				char c;

 				if (get_user(c, data + i))
 					return -EFAULT;

 				if (c == 'V')
 					safe_close = 1;
 			}
 		}

 		geodewdt_ping();
 	}
 	return len;
 }

 static int
 geodewdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 	       unsigned long arg)
 {
 	void __user *argp = (void __user *)arg;
 	int __user *p = argp;
 	int interval;

 	static struct watchdog_info ident = {
 		.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
 		| WDIOF_MAGICCLOSE,
 		.firmware_version =     1,
 		.identity =             WATCHDOG_NAME,
         };

 	switch(cmd) {
 	case WDIOC_GETSUPPORT:
 		return copy_to_user(argp, &ident,
 				    sizeof(ident)) ? -EFAULT : 0;
 		break;

 	case WDIOC_GETSTATUS:
 	case WDIOC_GETBOOTSTATUS:
 		return put_user(0, p);

 	case WDIOC_KEEPALIVE:
 		geodewdt_ping();
 		return 0;

 	case WDIOC_SETTIMEOUT:
 		if (get_user(interval, p))
 			return -EFAULT;

 		if (geodewdt_set_heartbeat(interval))
 			return -EINVAL;

 /* Fall through */

 	case WDIOC_GETTIMEOUT:
 		return put_user(timeout, p);

 	case WDIOC_SETOPTIONS:
 	{
 		int options, ret = -EINVAL;

 		if (get_user(options, p))
 			return -EFAULT;

 		if (options & WDIOS_DISABLECARD) {
 			geodewdt_disable();
 			ret = 0;
 		}

 		if (options & WDIOS_ENABLECARD) {
 			geodewdt_ping();
 			ret = 0;
 		}

 		return ret;
 	}
 	default:
 		return -ENOTTY;
 	}

 	return 0;
 }

 static const struct file_operations geodewdt_fops = {
         .owner          = THIS_MODULE,
         .llseek         = no_llseek,
         .write          = geodewdt_write,
         .ioctl          = geodewdt_ioctl,
         .open           = geodewdt_open,
         .release        = geodewdt_release,
 };

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

 static int __devinit
 geodewdt_probe(struct platform_device *dev)
 {
 	int ret, timer;

 	timer = geode_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);

 	if (timer == -1) {
 		printk(KERN_ERR "geodewdt:  No timers were available\n");
 		return -ENODEV;
 	}

 	wdt_timer = timer;

 	/* Set up the timer */

 	geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
 			  GEODEWDT_SCALE | (3 << 8));

 	/* Set up comparator 2 to reset when the event fires */
 	geode_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);

 	/* Set up the initial timeout */

 	geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
 		timeout * GEODEWDT_HZ);

 	ret = misc_register(&geodewdt_miscdev);

 	return ret;
 }

 static int __devexit
 geodewdt_remove(struct platform_device *dev)
 {
 	misc_deregister(&geodewdt_miscdev);
 	return 0;
 }

 static void
 geodewdt_shutdown(struct platform_device *dev)
 {
 	geodewdt_disable();
 }

 static struct platform_driver geodewdt_driver = {
 	.probe		= geodewdt_probe,
 	.remove		= __devexit_p(geodewdt_remove),
 	.shutdown	= geodewdt_shutdown,
 	.driver		= {
 		.owner	= THIS_MODULE,
 		.name	= DRV_NAME,
 	},
 };

 static int __init
 geodewdt_init(void)
 {
 	int ret;

 	ret = platform_driver_register(&geodewdt_driver);
 	if (ret)
 		return ret;

 	geodewdt_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
 	if (IS_ERR(geodewdt_platform_device)) {
 		ret = PTR_ERR(geodewdt_platform_device);
 		goto err;
 	}

 	return 0;
 err:
 	platform_driver_unregister(&geodewdt_driver);
 	return ret;
 }

 static void __exit
 geodewdt_exit(void)
 {
 	platform_device_unregister(geodewdt_platform_device);
 	platform_driver_unregister(&geodewdt_driver);
 }

 module_init(geodewdt_init);
 module_exit(geodewdt_exit);

 MODULE_AUTHOR("Advanced Micro Devices, Inc");
 MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	/* Watchdog timer for the Geode GX/LX with the CS5535/CS5536 companion chip
	*
	* Copyright (C) 2006-2007, Advanced Micro Devices, Inc.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*/


	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/types.h>
	#include <linux/miscdevice.h>
	#include <linux/watchdog.h>
	#include <linux/fs.h>
	#include <linux/platform_device.h>
	#include <linux/reboot.h>

	#include <asm/uaccess.h>
	#include <asm/geode.h>

	#define GEODEWDT_HZ 500
	#define GEODEWDT_SCALE 6
	#define GEODEWDT_MAX_SECONDS 131

	#define WDT_FLAGS_OPEN 1
	#define WDT_FLAGS_ORPHAN 2

	#define DRV_NAME "geodewdt"
	#define WATCHDOG_NAME "Geode GX/LX WDT"
	#define WATCHDOG_TIMEOUT 60

	static int timeout = WATCHDOG_TIMEOUT;
	module_param(timeout, int, 0);
	MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=131, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");

	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 struct platform_device *geodewdt_platform_device;
	static unsigned long wdt_flags;
	static int wdt_timer;
	static int safe_close;

	static void geodewdt_ping(void)
	{
	/* Stop the counter */
	geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);

	/* Reset the counter */
	geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);

	/* Enable the counter */
	geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
	}

	static void geodewdt_disable(void)
	{
	geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
	geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
	}

	static int geodewdt_set_heartbeat(int val)
	{
	if (val < 1 \|\| val > GEODEWDT_MAX_SECONDS)
	return -EINVAL;

	geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
	geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ);
	geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
	geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);

	timeout = val;
	return 0;
	}

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

	if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
	__module_get(THIS_MODULE);

	geodewdt_ping();
	return nonseekable_open(inode, file);
	}

	static int
	geodewdt_release(struct inode inode, struct file file)
	{
	if (safe_close) {
	geodewdt_disable();
	module_put(THIS_MODULE);
	}
	else {
	printk(KERN_CRIT "Unexpected close - watchdog is not stopping.\n");
	geodewdt_ping();

	set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
	}

	clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
	safe_close = 0;
	return 0;
	}

	static ssize_t
	geodewdt_write(struct file file, const char __user data, size_t len,
	loff_t *ppos)
	{
	if(len) {
	if (!nowayout) {
	size_t i;
	safe_close = 0;

	for (i = 0; i != len; i++) {
	char c;

	if (get_user(c, data + i))
	return -EFAULT;

	if (c == 'V')
	safe_close = 1;
	}
	}

	geodewdt_ping();
	}
	return len;
	}

	static int
	geodewdt_ioctl(struct inode inode, struct file file, unsigned int cmd,
	unsigned long arg)
	{
	void __user argp = (void __user )arg;
	int __user *p = argp;
	int interval;

	static struct watchdog_info ident = {
	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING
	\| WDIOF_MAGICCLOSE,
	.firmware_version = 1,
	.identity = WATCHDOG_NAME,
	};

	switch(cmd) {
	case WDIOC_GETSUPPORT:
	return copy_to_user(argp, &ident,
	sizeof(ident)) ? -EFAULT : 0;
	break;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
	return put_user(0, p);

	case WDIOC_KEEPALIVE:
	geodewdt_ping();
	return 0;

	case WDIOC_SETTIMEOUT:
	if (get_user(interval, p))
	return -EFAULT;

	if (geodewdt_set_heartbeat(interval))
	return -EINVAL;

	/* Fall through */

	case WDIOC_GETTIMEOUT:
	return put_user(timeout, p);

	case WDIOC_SETOPTIONS:
	{
	int options, ret = -EINVAL;

	if (get_user(options, p))
	return -EFAULT;

	if (options & WDIOS_DISABLECARD) {
	geodewdt_disable();
	ret = 0;
	}

	if (options & WDIOS_ENABLECARD) {
	geodewdt_ping();
	ret = 0;
	}

	return ret;
	}
	default:
	return -ENOTTY;
	}

	return 0;
	}

	static const struct file_operations geodewdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = geodewdt_write,
	.ioctl = geodewdt_ioctl,
	.open = geodewdt_open,
	.release = geodewdt_release,
	};

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

	static int __devinit
	geodewdt_probe(struct platform_device *dev)
	{
	int ret, timer;

	timer = geode_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);

	if (timer == -1) {
	printk(KERN_ERR "geodewdt: No timers were available\n");
	return -ENODEV;
	}

	wdt_timer = timer;

	/* Set up the timer */

	geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
	GEODEWDT_SCALE \| (3 << 8));

	/* Set up comparator 2 to reset when the event fires */
	geode_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);

	/* Set up the initial timeout */

	geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
	timeout * GEODEWDT_HZ);

	ret = misc_register(&geodewdt_miscdev);

	return ret;
	}

	static int __devexit
	geodewdt_remove(struct platform_device *dev)
	{
	misc_deregister(&geodewdt_miscdev);
	return 0;
	}

	static void
	geodewdt_shutdown(struct platform_device *dev)
	{
	geodewdt_disable();
	}

	static struct platform_driver geodewdt_driver = {
	.probe = geodewdt_probe,
	.remove = __devexit_p(geodewdt_remove),
	.shutdown = geodewdt_shutdown,
	.driver = {
	.owner = THIS_MODULE,
	.name = DRV_NAME,
	},
	};

	static int __init
	geodewdt_init(void)
	{
	int ret;

	ret = platform_driver_register(&geodewdt_driver);
	if (ret)
	return ret;

	geodewdt_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
	if (IS_ERR(geodewdt_platform_device)) {
	ret = PTR_ERR(geodewdt_platform_device);
	goto err;
	}

	return 0;
	err:
	platform_driver_unregister(&geodewdt_driver);
	return ret;
	}

	static void __exit
	geodewdt_exit(void)
	{
	platform_device_unregister(geodewdt_platform_device);
	platform_driver_unregister(&geodewdt_driver);
	}

	module_init(geodewdt_init);
	module_exit(geodewdt_exit);

	MODULE_AUTHOR("Advanced Micro Devices, Inc");
	MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);