1 files changed, 310 insertions, 0 deletions

diff --git a/drivers/watchdog/softdog.c b/drivers/watchdog/softdog.c
new file mode 100644
index 000000000000..9c3694909243
--- /dev/null
+++ b/drivers/watchdog/softdog.c
@@ -0,0 +1,310 @@
+/*
+ *      SoftDog 0.07:   A Software Watchdog Device
+ *
+ *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
+ *                              http://www.redhat.com
+ *
+ *      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.
+ *
+ *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
+ *      warranty for any of this software. This material is provided
+ *      "AS-IS" and at no charge.
+ *
+ *      (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
+ *
+ *      Software only watchdog driver. Unlike its big brother the WDT501P
+ *      driver this won't always recover a failed machine.
+ *
+ *  03/96: Angelo Haritsis <ah@doc.ic.ac.uk> :
+ *      Modularised.
+ *      Added soft_margin; use upon insmod to change the timer delay.
+ *      NB: uses same minor as wdt (WATCHDOG_MINOR); we could use separate
+ *          minors.
+ *
+ *  19980911 Alan Cox
+ *      Made SMP safe for 2.3.x
+ *
+ *  20011127 Joel Becker (jlbec@evilplan.org>
+ *      Added soft_noboot; Allows testing the softdog trigger without
+ *      requiring a recompile.
+ *      Added WDIOC_GETTIMEOUT and WDIOC_SETTIMOUT.
+ *
+ *  20020530 Joel Becker <joel.becker@oracle.com>
+ *      Added Matt Domsch's nowayout module option.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/timer.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+
+#include <asm/uaccess.h>
+
+#define PFX "SoftDog: "
+
+#define TIMER_MARGIN    60              /* Default is 60 seconds */
+static int soft_margin = TIMER_MARGIN;  /* in seconds */
+module_param(soft_margin, int, 0);
+MODULE_PARM_DESC(soft_margin, "Watchdog soft_margin in seconds. (0<soft_margin<65536, default=" __MODULE_STRING(TIMER_MARGIN) ")");
+
+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) ")");
+
+#ifdef ONLY_TESTING
+static int soft_noboot = 1;
+#else
+static int soft_noboot = 0;
+#endif  /* ONLY_TESTING */
+
+module_param(soft_noboot, int, 0);
+MODULE_PARM_DESC(soft_noboot, "Softdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)");
+
+/*
+ *      Our timer
+ */
+
+static void watchdog_fire(unsigned long);
+
+static struct timer_list watchdog_ticktock =
+                TIMER_INITIALIZER(watchdog_fire, 0, 0);
+static unsigned long driver_open, orphan_timer;
+static char expect_close;
+
+
+/*
+ *      If the timer expires..
+ */
+
+static void watchdog_fire(unsigned long data)
+{
+        if (test_and_clear_bit(0, &orphan_timer))
+                module_put(THIS_MODULE);
+
+        if (soft_noboot)
+                printk(KERN_CRIT PFX "Triggered - Reboot ignored.\n");
+        else
+        {
+                printk(KERN_CRIT PFX "Initiating system reboot.\n");
+                emergency_restart();
+                printk(KERN_CRIT PFX "Reboot didn't ?????\n");
+        }
+}
+
+/*
+ *      Softdog operations
+ */
+
+static int softdog_keepalive(void)
+{
+        mod_timer(&watchdog_ticktock, jiffies+(soft_margin*HZ));
+        return 0;
+}
+
+static int softdog_stop(void)
+{
+        del_timer(&watchdog_ticktock);
+        return 0;
+}
+
+static int softdog_set_heartbeat(int t)
+{
+        if ((t < 0x0001) || (t > 0xFFFF))
+                return -EINVAL;
+
+        soft_margin = t;
+        return 0;
+}
+
+/*
+ *      /dev/watchdog handling
+ */
+
+static int softdog_open(struct inode *inode, struct file *file)
+{
+        if (test_and_set_bit(0, &driver_open))
+                return -EBUSY;
+        if (!test_and_clear_bit(0, &orphan_timer))
+                __module_get(THIS_MODULE);
+        /*
+         *      Activate timer
+         */
+        softdog_keepalive();
+        return nonseekable_open(inode, file);
+}
+
+static int softdog_release(struct inode *inode, struct file *file)
+{
+        /*
+         *      Shut off the timer.
+         *      Lock it in if it's a module and we set nowayout
+         */
+        if (expect_close == 42) {
+                softdog_stop();
+                module_put(THIS_MODULE);
+        } else {
+                printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
+                set_bit(0, &orphan_timer);
+                softdog_keepalive();
+        }
+        clear_bit(0, &driver_open);
+        expect_close = 0;
+        return 0;
+}
+
+static ssize_t softdog_write(struct file *file, const char __user *data, size_t len, loff_t *ppos)
+{
+        /*
+         *      Refresh the timer.
+         */
+        if(len) {
+                if (!nowayout) {
+                        size_t i;
+
+                        /* In case it was set long ago */
+                        expect_close = 0;
+
+                        for (i = 0; i != len; i++) {
+                                char c;
+
+                                if (get_user(c, data + i))
+                                        return -EFAULT;
+                                if (c == 'V')
+                                        expect_close = 42;
+                        }
+                }
+                softdog_keepalive();
+        }
+        return len;
+}
+
+static int softdog_ioctl(struct inode *inode, struct file *file,
+        unsigned int cmd, unsigned long arg)
+{
+        void __user *argp = (void __user *)arg;
+        int __user *p = argp;
+        int new_margin;
+        static struct watchdog_info ident = {
+                .options =              WDIOF_SETTIMEOUT |
+                                        WDIOF_KEEPALIVEPING |
+                                        WDIOF_MAGICCLOSE,
+                .firmware_version =     0,
+                .identity =             "Software Watchdog",
+        };
+        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:
+                        softdog_keepalive();
+                        return 0;
+                case WDIOC_SETTIMEOUT:
+                        if (get_user(new_margin, p))
+                                return -EFAULT;
+                        if (softdog_set_heartbeat(new_margin))
+                                return -EINVAL;
+                        softdog_keepalive();
+                        /* Fall */
+                case WDIOC_GETTIMEOUT:
+                        return put_user(soft_margin, p);
+        }
+}
+
+/*
+ *      Notifier for system down
+ */
+
+static int softdog_notify_sys(struct notifier_block *this, unsigned long code,
+        void *unused)
+{
+        if(code==SYS_DOWN || code==SYS_HALT) {
+                /* Turn the WDT off */
+                softdog_stop();
+        }
+        return NOTIFY_DONE;
+}
+
+/*
+ *      Kernel Interfaces
+ */
+
+static const struct file_operations softdog_fops = {
+        .owner          = THIS_MODULE,
+        .llseek         = no_llseek,
+        .write          = softdog_write,
+        .ioctl          = softdog_ioctl,
+        .open           = softdog_open,
+        .release        = softdog_release,
+};
+
+static struct miscdevice softdog_miscdev = {
+        .minor          = WATCHDOG_MINOR,
+        .name           = "watchdog",
+        .fops           = &softdog_fops,
+};
+
+static struct notifier_block softdog_notifier = {
+        .notifier_call  = softdog_notify_sys,
+};
+
+static char banner[] __initdata = KERN_INFO "Software Watchdog Timer: 0.07 initialized. soft_noboot=%d soft_margin=%d sec (nowayout= %d)\n";
+
+static int __init watchdog_init(void)
+{
+        int ret;
+
+        /* Check that the soft_margin value is within it's range ; if not reset to the default */
+        if (softdog_set_heartbeat(soft_margin)) {
+                softdog_set_heartbeat(TIMER_MARGIN);
+                printk(KERN_INFO PFX "soft_margin value must be 0<soft_margin<65536, using %d\n",
+                        TIMER_MARGIN);
+        }
+
+        ret = register_reboot_notifier(&softdog_notifier);
+        if (ret) {
+                printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
+                        ret);
+                return ret;
+        }
+
+        ret = misc_register(&softdog_miscdev);
+        if (ret) {
+                printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
+                        WATCHDOG_MINOR, ret);
+                unregister_reboot_notifier(&softdog_notifier);
+                return ret;
+        }
+
+        printk(banner, soft_noboot, soft_margin, nowayout);
+
+        return 0;
+}
+
+static void __exit watchdog_exit(void)
+{
+        misc_deregister(&softdog_miscdev);
+        unregister_reboot_notifier(&softdog_notifier);
+}
+
+module_init(watchdog_init);
+module_exit(watchdog_exit);
+
+MODULE_AUTHOR("Alan Cox");
+MODULE_DESCRIPTION("Software Watchdog Device Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);