| /* |
| * 60xx Single Board Computer Watchdog Timer driver for Linux 2.2.x |
| * |
| * Based on acquirewdt.c by Alan Cox. |
| * |
| * 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 author does 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 2000 Jakob Oestergaard <jakob@unthought.net> |
| * |
| * 12/4 - 2000 [Initial revision] |
| * 25/4 - 2000 Added /dev/watchdog support |
| * 09/5 - 2001 [smj@oro.net] fixed fop_write to "return 1" |
| * on success |
| * 12/4 - 2002 [rob@osinvestor.com] eliminate fop_read |
| * fix possible wdt_is_open race |
| * add CONFIG_WATCHDOG_NOWAYOUT support |
| * remove lock_kernel/unlock_kernel pairs |
| * added KERN_* to printk's |
| * got rid of extraneous comments |
| * 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 |
| * use module_param |
| * made timeout (the emulated heartbeat) a |
| * module_param |
| * made the keepalive ping an internal subroutine |
| * made wdt_stop and wdt_start module params |
| * added extra printk's for startup problems |
| * added MODULE_AUTHOR and MODULE_DESCRIPTION info |
| * |
| * |
| * This WDT driver is different from the other Linux WDT |
| * drivers in the following ways: |
| * *) The driver will ping the watchdog by itself, because this |
| * particular WDT has a very short timeout (one second) and it |
| * would be insane to count on any userspace daemon always |
| * getting scheduled within that time frame. |
| * |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/module.h> |
| #include <linux/moduleparam.h> |
| #include <linux/types.h> |
| #include <linux/timer.h> |
| #include <linux/jiffies.h> |
| #include <linux/miscdevice.h> |
| #include <linux/watchdog.h> |
| #include <linux/fs.h> |
| #include <linux/ioport.h> |
| #include <linux/notifier.h> |
| #include <linux/reboot.h> |
| #include <linux/init.h> |
| #include <linux/io.h> |
| #include <linux/uaccess.h> |
| |
| |
| #define OUR_NAME "sbc60xxwdt" |
| #define PFX OUR_NAME ": " |
| |
| /* |
| * You must set these - The driver cannot probe for the settings |
| */ |
| |
| static int wdt_stop = 0x45; |
| module_param(wdt_stop, int, 0); |
| MODULE_PARM_DESC(wdt_stop, "SBC60xx WDT 'stop' io port (default 0x45)"); |
| |
| static int wdt_start = 0x443; |
| module_param(wdt_start, int, 0); |
| MODULE_PARM_DESC(wdt_start, "SBC60xx WDT 'start' io port (default 0x443)"); |
| |
| /* |
| * The 60xx board can use watchdog timeout values from one second |
| * to several minutes. The default is one second, so 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. |
| * If the daemon pulses us every 25 seconds, we can still afford |
| * a 5 second scheduling delay on the (high priority) daemon. That |
| * should be sufficient for a box under any load. |
| */ |
| |
| #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ |
| static int timeout = WATCHDOG_TIMEOUT; /* in seconds, 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 bool nowayout = WATCHDOG_NOWAYOUT; |
| module_param(nowayout, bool, 0); |
| MODULE_PARM_DESC(nowayout, |
| "Watchdog cannot be stopped once started (default=" |
| __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| |
| static void wdt_timer_ping(struct timer_list *); |
| static DEFINE_TIMER(timer, wdt_timer_ping); |
| static unsigned long next_heartbeat; |
| static unsigned long wdt_is_open; |
| static char wdt_expect_close; |
| |
| /* |
| * Whack the dog |
| */ |
| |
| static void wdt_timer_ping(struct timer_list *unused) |
| { |
| /* 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 by reading from wdt_start */ |
| inb_p(wdt_start); |
| /* Re-set the timer interval */ |
| mod_timer(&timer, jiffies + WDT_INTERVAL); |
| } else |
| pr_warn("Heartbeat lost! Will not ping the watchdog\n"); |
| } |
| |
| /* |
| * Utility routines |
| */ |
| |
| static void wdt_startup(void) |
| { |
| next_heartbeat = jiffies + (timeout * HZ); |
| |
| /* Start the timer */ |
| mod_timer(&timer, jiffies + WDT_INTERVAL); |
| pr_info("Watchdog timer is now enabled\n"); |
| } |
| |
| static void wdt_turnoff(void) |
| { |
| /* Stop the timer */ |
| del_timer(&timer); |
| inb_p(wdt_stop); |
| pr_info("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; |
| } |
| } |
| |
| /* Well, anyhow someone wrote to us, we should |
| return that favour */ |
| 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; |
| |
| if (nowayout) |
| __module_get(THIS_MODULE); |
| |
| /* 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); |
| pr_crit("device file closed unexpectedly. Will not stop the WDT!\n"); |
| } |
| clear_bit(0, &wdt_is_open); |
| wdt_expect_close = 0; |
| return 0; |
| } |
| |
| static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| void __user *argp = (void __user *)arg; |
| int __user *p = argp; |
| static const struct watchdog_info ident = { |
| .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | |
| WDIOF_MAGICCLOSE, |
| .firmware_version = 1, |
| .identity = "SBC60xx", |
| }; |
| |
| switch (cmd) { |
| 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_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_KEEPALIVE: |
| wdt_keepalive(); |
| return 0; |
| case WDIOC_SETTIMEOUT: |
| { |
| int new_timeout; |
| if (get_user(new_timeout, p)) |
| return -EFAULT; |
| /* arbitrary upper limit */ |
| if (new_timeout < 1 || new_timeout > 3600) |
| return -EINVAL; |
| |
| timeout = new_timeout; |
| wdt_keepalive(); |
| /* Fall through */ |
| } |
| case WDIOC_GETTIMEOUT: |
| return put_user(timeout, p); |
| default: |
| return -ENOTTY; |
| } |
| } |
| |
| static const struct file_operations wdt_fops = { |
| .owner = THIS_MODULE, |
| .llseek = no_llseek, |
| .write = fop_write, |
| .open = fop_open, |
| .release = fop_close, |
| .unlocked_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 sbc60xxwdt_unload(void) |
| { |
| wdt_turnoff(); |
| |
| /* Deregister */ |
| misc_deregister(&wdt_miscdev); |
| |
| unregister_reboot_notifier(&wdt_notifier); |
| if ((wdt_stop != 0x45) && (wdt_stop != wdt_start)) |
| release_region(wdt_stop, 1); |
| release_region(wdt_start, 1); |
| } |
| |
| static int __init sbc60xxwdt_init(void) |
| { |
| int rc = -EBUSY; |
| |
| if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */ |
| timeout = WATCHDOG_TIMEOUT; |
| pr_info("timeout value must be 1 <= x <= 3600, using %d\n", |
| timeout); |
| } |
| |
| if (!request_region(wdt_start, 1, "SBC 60XX WDT")) { |
| pr_err("I/O address 0x%04x already in use\n", wdt_start); |
| rc = -EIO; |
| goto err_out; |
| } |
| |
| /* We cannot reserve 0x45 - the kernel already has! */ |
| if (wdt_stop != 0x45 && wdt_stop != wdt_start) { |
| if (!request_region(wdt_stop, 1, "SBC 60XX WDT")) { |
| pr_err("I/O address 0x%04x already in use\n", wdt_stop); |
| rc = -EIO; |
| goto err_out_region1; |
| } |
| } |
| |
| rc = register_reboot_notifier(&wdt_notifier); |
| if (rc) { |
| pr_err("cannot register reboot notifier (err=%d)\n", rc); |
| goto err_out_region2; |
| } |
| |
| rc = misc_register(&wdt_miscdev); |
| if (rc) { |
| pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
| wdt_miscdev.minor, rc); |
| goto err_out_reboot; |
| } |
| pr_info("WDT driver for 60XX single board computer initialised. timeout=%d sec (nowayout=%d)\n", |
| timeout, nowayout); |
| |
| return 0; |
| |
| err_out_reboot: |
| unregister_reboot_notifier(&wdt_notifier); |
| err_out_region2: |
| if (wdt_stop != 0x45 && wdt_stop != wdt_start) |
| release_region(wdt_stop, 1); |
| err_out_region1: |
| release_region(wdt_start, 1); |
| err_out: |
| return rc; |
| } |
| |
| module_init(sbc60xxwdt_init); |
| module_exit(sbc60xxwdt_unload); |
| |
| MODULE_AUTHOR("Jakob Oestergaard <jakob@unthought.net>"); |
| MODULE_DESCRIPTION("60xx Single Board Computer Watchdog Timer driver"); |
| MODULE_LICENSE("GPL"); |