The following is a patch against the 2.5.60 kernel that ports the softdog driver to register as a watchdog_driver and allow the watchdog infrastructure to take care of details like sysfs and presenting a miscdevice for the watchdog minor. There are enough changes to make the patch difficult to read so I am also attaching softdog.c to make it easier to see what the file is doing. --rustyl # This is a BitKeeper generated patch for the following project: # Project Name: Linux kernel tree # This patch format is intended for GNU patch command version 2.5 or higher. # This patch includes the following deltas: # ChangeSet 1.1040 -> 1.1041 # drivers/char/watchdog/softdog.c 1.14 -> 1.15 # # The following is the BitKeeper ChangeSet Log # -------------------------------------------- # 03/02/21 rusty@penguin.co.intel.com 1.1041 # * ported driver to new sysfs based watchdog infrastructure # * change from using old MODULE_PARM macro to the new module_param # function call # -------------------------------------------- # diff -Nru a/drivers/char/watchdog/softdog.c b/drivers/char/watchdog/softdog.c --- a/drivers/char/watchdog/softdog.c Fri Feb 21 14:48:49 2003 +++ b/drivers/char/watchdog/softdog.c Fri Feb 21 14:48:49 2003 @@ -1,5 +1,5 @@ /* - * SoftDog 0.06: A Software Watchdog Device + * SoftDog 0.07: A Software Watchdog Device * * (c) Copyright 1996 Alan Cox , All Rights Reserved. * http://www.redhat.com @@ -34,52 +34,41 @@ * * 20020530 Joel Becker * Added Matt Domsch's nowayout module option. + * + * 20030221 Rusty Lynch + * Moved implementation to use the new watchdog infrastructure. This + * adds the softdog to the sysfs topography and moves the common + * miscdevice functions to the infrastructure as well. + * */ #include +#include #include #include -#include #include #include #include #include #define TIMER_MARGIN 60 /* (secs) Default is 1 minute */ - -static int expect_close = 0; static int soft_margin = TIMER_MARGIN; /* in seconds */ -#ifdef ONLY_TESTING -static int soft_noboot = 1; -#else -static int soft_noboot = 0; -#endif /* ONLY_TESTING */ +module_param(soft_margin,int,0); +MODULE_PARM_DESC(soft_margin, "Watchdog timer margin (timeout) in seconds"); -MODULE_PARM(soft_margin,"i"); -MODULE_PARM(soft_noboot,"i"); -MODULE_LICENSE("GPL"); +static int soft_noboot = 0; +module_param(soft_noboot,int,0); +MODULE_PARM_DESC(soft_noboot, "Disable machine restarts on watchdog timeout"); #ifdef CONFIG_WATCHDOG_NOWAYOUT static int nowayout = 1; #else static int nowayout = 0; #endif - -MODULE_PARM(nowayout,"i"); +module_param(nowayout,int,0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); /* - * Our timer - */ - -static void watchdog_fire(unsigned long); - -static struct timer_list watchdog_ticktock = - TIMER_INITIALIZER(watchdog_fire, 0, 0); -static unsigned long timer_alive; - - -/* * If the timer expires.. */ @@ -96,137 +85,154 @@ } /* - * Allow only one person to hold it open + * Software timer */ -static int softdog_open(struct inode *inode, struct file *file) +static struct timer_list watchdog_ticktock = + TIMER_INITIALIZER(watchdog_fire, 0, 0); + + +/* + * Watchdog ops callback functions + */ + +static int softdog_start(struct watchdog_driver *d) { - if(test_and_set_bit(0, &timer_alive)) - return -EBUSY; - if (nowayout) { - MOD_INC_USE_COUNT; - } - /* - * Activate timer - */ mod_timer(&watchdog_ticktock, jiffies+(soft_margin*HZ)); return 0; } -static int softdog_release(struct inode *inode, struct file *file) +static int softdog_stop(struct watchdog_driver *d) { - /* - * Shut off the timer. - * Lock it in if it's a module and we set nowayout - */ - if (expect_close) { - del_timer(&watchdog_ticktock); - } else { - printk(KERN_CRIT "SOFTDOG: WDT device closed unexpectedly. WDT will not stop!\n"); + if (nowayout) { + printk(KERN_CRIT "SOFTDOG: WDT device closed unexpectedly. " + "WDT will not stop!\n"); + return -1; } - clear_bit(0, &timer_alive); + + del_timer(&watchdog_ticktock); return 0; } -static ssize_t softdog_write(struct file *file, const char *data, size_t len, loff_t *ppos) +static int softdog_keepalive(struct watchdog_driver *d) { - /* Can't seek (pwrite) on this device */ - if (ppos != &file->f_pos) - return -ESPIPE; + mod_timer(&watchdog_ticktock, jiffies+(soft_margin*HZ)); + return 0; +} - /* - * Refresh the timer. - */ - if(len) { - if (!nowayout) { - size_t i; +static int softdog_get_timeout(struct watchdog_driver *d, int *timeout) +{ + *timeout = soft_margin; + return 0; +} - /* In case it was set long ago */ - expect_close = 0; +static int softdog_set_timeout(struct watchdog_driver *d, int timeout) +{ + if (timeout < 1) + return -1; - for (i = 0; i != len; i++) { - char c; + soft_margin = timeout; + mod_timer(&watchdog_ticktock, jiffies+(soft_margin*HZ)); + return 0; +} - if (get_user(c, data + i)) - return -EFAULT; - if (c == 'V') - expect_close = 1; - } - } - mod_timer(&watchdog_ticktock, jiffies+(soft_margin*HZ)); - return 1; - } +static int softdog_get_options(struct watchdog_driver *d, int *options) +{ + *options = WDIOF_SETTIMEOUT; return 0; } -static int softdog_ioctl(struct inode *inode, struct file *file, - unsigned int cmd, unsigned long arg) +static int softdog_get_nowayout(struct watchdog_driver *d, int *n) { - int new_margin; - static struct watchdog_info ident = { - .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, - .identity = "Software Watchdog", - }; - switch (cmd) { - default: - return -ENOTTY; - case WDIOC_GETSUPPORT: - if(copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident))) - return -EFAULT; - return 0; - case WDIOC_GETSTATUS: - case WDIOC_GETBOOTSTATUS: - return put_user(0,(int *)arg); - case WDIOC_KEEPALIVE: - mod_timer(&watchdog_ticktock, jiffies+(soft_margin*HZ)); - return 0; - case WDIOC_SETTIMEOUT: - if (get_user(new_margin, (int *)arg)) - return -EFAULT; - if (new_margin < 1) - return -EINVAL; - soft_margin = new_margin; - mod_timer(&watchdog_ticktock, jiffies+(soft_margin*HZ)); - /* Fall */ - case WDIOC_GETTIMEOUT: - return put_user(soft_margin, (int *)arg); - } + *n = nowayout; + return 0; } -static struct file_operations softdog_fops = { - .owner = THIS_MODULE, - .write = softdog_write, - .ioctl = softdog_ioctl, - .open = softdog_open, - .release = softdog_release, +static int softdog_set_nowayout(struct watchdog_driver *d, int n) +{ + if (n) + nowayout = 1; + else + nowayout = 0; + return 0; +} + +/* + * Structures required to register as a watchdog driver + */ + +static struct watchdog_ops softdog_ops = { + .start = softdog_start, + .stop = softdog_stop, + .keepalive = softdog_keepalive, + .get_timeout = softdog_get_timeout, + .set_timeout = softdog_set_timeout, + .get_nowayout = softdog_get_nowayout, + .set_nowayout = softdog_set_nowayout, + .get_options = softdog_get_options, + /* get_bootstatus not implemented */ + /* get_status not implemented */ + /* get/set_temppanic not implemented */ + /* get_firmware_version not implemented */ }; -static struct miscdevice softdog_miscdev = { - .minor = WATCHDOG_MINOR, - .name = "watchdog", - .fops = &softdog_fops, +static struct watchdog_driver softdog_driver = { + .ops = &softdog_ops, + .driver = { + .name = "softdog", + .bus = &system_bus_type, + .devclass = &watchdog_devclass, + } }; -static char banner[] __initdata = KERN_INFO "Software Watchdog Timer: 0.06, soft_margin: %d sec, nowayout: %d\n"; +/* + * enable testing the of driver to not cause a machine restart + */ + +static ssize_t soft_noboot_show(struct device_driver * d, char * buf) +{ + return sprintf(buf, "%i\n",soft_noboot); +} +static ssize_t soft_noboot_store(struct device_driver *d,const char * buf, + size_t count) +{ + int tmp; + + if (sscanf(buf,"%i",&tmp) != 1) + return -EINVAL; + + if (tmp) + soft_noboot = 1; + else + soft_noboot = 0; + return count; +} +DRIVER_ATTR(soft_noboot,0644,soft_noboot_show,soft_noboot_store); + +static char banner[] __initdata = KERN_INFO "Software Watchdog Timer: 0.07, soft_margin: %d sec, nowayout: %d\n"; static int __init watchdog_init(void) { int ret; - ret = misc_register(&softdog_miscdev); - + ret = watchdog_driver_register(&softdog_driver); if (ret) return ret; + driver_create_file(&softdog_driver.driver, &driver_attr_soft_noboot); printk(banner, soft_margin, nowayout); - return 0; } static void __exit watchdog_exit(void) -{ - misc_deregister(&softdog_miscdev); +{ + driver_remove_file(&softdog_driver.driver, &driver_attr_soft_noboot); + watchdog_driver_unregister(&softdog_driver); + + /* ensure somebody didn't leave the watchdog ticking */ + del_timer(&watchdog_ticktock); } module_init(watchdog_init); module_exit(watchdog_exit); +MODULE_LICENSE("GPL");