diff options
Diffstat (limited to 'drivers/watchdog/sbc60xxwdt.c')
| -rw-r--r-- | drivers/watchdog/sbc60xxwdt.c | 390 |
1 files changed, 390 insertions, 0 deletions
diff --git a/drivers/watchdog/sbc60xxwdt.c b/drivers/watchdog/sbc60xxwdt.c new file mode 100644 index 00000000..63632ec8 --- /dev/null +++ b/drivers/watchdog/sbc60xxwdt.c @@ -0,0 +1,390 @@ +/* + * 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(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; + +/* + * 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 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"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |