/* * W83877F Computer Watchdog Timer driver * * Based on acquirewdt.c by Alan Cox, * and sbc60xxwdt.c by Jakob Oestergaard * * 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. * * The authors do NOT admit liability nor provide warranty for * any of this software. This material is provided "AS-IS" in * the hope that it may be useful for others. * * (c) Copyright 2001 Scott Jennings * * 4/19 - 2001 [Initial revision] * 9/27 - 2001 Added spinlocking * 4/12 - 2002 [rob@osinvestor.com] Eliminate extra comments * Eliminate fop_read * Eliminate extra spin_unlock * Added KERN_* tags to printks * add CONFIG_WATCHDOG_NOWAYOUT support * fix possible wdt_is_open race * changed watchdog_info to correctly reflect what the driver offers * added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS, WDIOC_SETTIMEOUT, * WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls * 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces * added extra printk's for startup problems * use module_param * made timeout (the emulated heartbeat) a module_param * made the keepalive ping an internal subroutine * * This WDT driver is different from most other Linux WDT * drivers in that the driver will ping the watchdog by itself, * because this particular WDT has a very short timeout (1.6 * seconds) and it would be insane to count on any userspace * daemon always getting scheduled within that time frame. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define OUR_NAME "w83877f_wdt" #define PFX OUR_NAME ": " #define ENABLE_W83877F_PORT 0x3F0 #define ENABLE_W83877F 0x87 #define DISABLE_W83877F 0xAA #define WDT_PING 0x443 #define WDT_REGISTER 0x14 #define WDT_ENABLE 0x9C #define WDT_DISABLE 0x8C /* * The W83877F seems to be fixed at 1.6s timeout (at least on the * EMACS PC-104 board I'm using). If we reset the watchdog every * ~250ms we should be safe. */ #define WDT_INTERVAL (HZ/4+1) /* * We must not require too good response from the userspace daemon. * Here we require the userspace daemon to send us a heartbeat * char to /dev/watchdog every 30 seconds. */ #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ module_param(timeout, int, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, 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 void wdt_timer_ping(unsigned long); static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0); static unsigned long next_heartbeat; static unsigned long wdt_is_open; static char wdt_expect_close; static DEFINE_SPINLOCK(wdt_spinlock); /* * Whack the dog */ static void wdt_timer_ping(unsigned long data) { /* If we got a heartbeat pulse within the WDT_US_INTERVAL * we agree to ping the WDT */ if(time_before(jiffies, next_heartbeat)) { /* Ping the WDT */ spin_lock(&wdt_spinlock); /* Ping the WDT by reading from WDT_PING */ inb_p(WDT_PING); /* Re-set the timer interval */ mod_timer(&timer, jiffies + WDT_INTERVAL); spin_unlock(&wdt_spinlock); } else { printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n"); } } /* * Utility routines */ static void wdt_change(int writeval) { unsigned long flags; spin_lock_irqsave(&wdt_spinlock, flags); /* buy some time */ inb_p(WDT_PING); /* make W83877F available */ outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); /* enable watchdog */ outb_p(WDT_REGISTER, ENABLE_W83877F_PORT); outb_p(writeval, ENABLE_W83877F_PORT+1); /* lock the W8387FF away */ outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT); spin_unlock_irqrestore(&wdt_spinlock, flags); } static void wdt_startup(void) { next_heartbeat = jiffies + (timeout * HZ); /* Start the timer */ mod_timer(&timer, jiffies + WDT_INTERVAL); wdt_change(WDT_ENABLE); printk(KERN_INFO PFX "Watchdog timer is now enabled.\n"); } static void wdt_turnoff(void) { /* Stop the timer */ del_timer(&timer); wdt_change(WDT_DISABLE); printk(KERN_INFO PFX "Watchdog timer is now disabled...\n"); } static void wdt_keepalive(void) { /* user land ping */ next_heartbeat = jiffies + (timeout * HZ); } /* * /dev/watchdog handling */ static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos) { /* See if we got the magic character 'V' and reload the timer */ if(count) { if (!nowayout) { size_t ofs; /* note: just in case someone wrote the magic character * five months ago... */ wdt_expect_close = 0; /* scan to see whether or not we got the magic character */ for(ofs = 0; ofs != count; ofs++) { char c; if (get_user(c, buf + ofs)) return -EFAULT; if (c == 'V') wdt_expect_close = 42; } } /* someone wrote to us, we should restart timer */ wdt_keepalive(); } return count; } static int fop_open(struct inode * inode, struct file * file) { /* Just in case we're already talking to someone... */ if(test_and_set_bit(0, &wdt_is_open)) return -EBUSY; /* Good, fire up the show */ wdt_startup(); return nonseekable_open(inode, file); } static int fop_close(struct inode * inode, struct file * file) { if(wdt_expect_close == 42) wdt_turnoff(); else { del_timer(&timer); printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n"); } clear_bit(0, &wdt_is_open); wdt_expect_close = 0; return 0; } static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { void __user *argp = (void __user *)arg; int __user *p = argp; static struct watchdog_info ident= { .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, .firmware_version = 1, .identity = "W83877F", }; switch(cmd) { default: return -ENOTTY; case WDIOC_GETSUPPORT: return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, p); case WDIOC_KEEPALIVE: wdt_keepalive(); return 0; case WDIOC_SETOPTIONS: { int new_options, retval = -EINVAL; if(get_user(new_options, p)) return -EFAULT; if(new_options & WDIOS_DISABLECARD) { wdt_turnoff(); retval = 0; } if(new_options & WDIOS_ENABLECARD) { wdt_startup(); retval = 0; } return retval; } case WDIOC_SETTIMEOUT: { int new_timeout; if(get_user(new_timeout, p)) return -EFAULT; if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */ return -EINVAL; timeout = new_timeout; wdt_keepalive(); /* Fall through */ } case WDIOC_GETTIMEOUT: return put_user(timeout, p); } } static const struct file_operations wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = fop_write, .open = fop_open, .release = fop_close, .ioctl = fop_ioctl, }; static struct miscdevice wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &wdt_fops, }; /* * Notifier for system down */ static int wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if(code==SYS_DOWN || code==SYS_HALT) wdt_turnoff(); return NOTIFY_DONE; } /* * The WDT needs to learn about soft shutdowns in order to * turn the timebomb registers off. */ static struct notifier_block wdt_notifier= { .notifier_call = wdt_notify_sys, }; static void __exit w83877f_wdt_unload(void) { wdt_turnoff(); /* Deregister */ misc_deregister(&wdt_miscdev); unregister_reboot_notifier(&wdt_notifier); release_region(WDT_PING,1); release_region(ENABLE_W83877F_PORT,2); } static int __init w83877f_wdt_init(void) { int rc = -EBUSY; if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */ { timeout = WATCHDOG_TIMEOUT; printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n", timeout); } if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) { printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", ENABLE_W83877F_PORT); rc = -EIO; goto err_out; } if (!request_region(WDT_PING, 1, "W8387FF WDT")) { printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", WDT_PING); rc = -EIO; goto err_out_region1; } rc = register_reboot_notifier(&wdt_notifier); if (rc) { printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", rc); goto err_out_region2; } rc = misc_register(&wdt_miscdev); if (rc) { printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", wdt_miscdev.minor, rc); goto err_out_reboot; } printk(KERN_INFO PFX "WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n", timeout, nowayout); return 0; err_out_reboot: unregister_reboot_notifier(&wdt_notifier); err_out_region2: release_region(WDT_PING,1); err_out_region1: release_region(ENABLE_W83877F_PORT,2); err_out: return rc; } module_init(w83877f_wdt_init); module_exit(w83877f_wdt_unload); MODULE_AUTHOR("Scott and Bill Jennings"); MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);