1 files changed, 415 insertions, 0 deletions

diff --git a/drivers/watchdog/w83877f_wdt.c b/drivers/watchdog/w83877f_wdt.c
new file mode 100644
index 000000000000..3c88fe18f4f4
--- /dev/null
+++ b/drivers/watchdog/w83877f_wdt.c
@@ -0,0 +1,415 @@
+/*
+ *      W83877F Computer Watchdog Timer driver
+ *
+ *      Based on acquirewdt.c by Alan Cox,
+ *           and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
+ *
+ *      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 <linuxdrivers@oro.net>
+ *
+ *           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 <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 <asm/io.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+
+#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 spinlock_t 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;
+
+        spin_lock_init(&wdt_spinlock);
+
+        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 = 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_region2;
+        }
+
+        rc = register_reboot_notifier(&wdt_notifier);
+        if (rc)
+        {
+                printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
+                        rc);
+                goto err_out_miscdev;
+        }
+
+        printk(KERN_INFO PFX "WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n",
+                timeout, nowayout);
+
+        return 0;
+
+err_out_miscdev:
+        misc_deregister(&wdt_miscdev);
+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);