--- /dev/null
+/*
+ * 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.
+ */
+
+#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 "w83877f_wdt"
+
+#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 */
+/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
+static int timeout = WATCHDOG_TIMEOUT;
+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;
+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
+ pr_warn("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);
+
+ pr_info("Watchdog timer is now enabled\n");
+}
+
+static void wdt_turnoff(void)
+{
+ /* Stop the timer */
+ del_timer(&timer);
+
+ wdt_change(WDT_DISABLE);
+
+ 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;
+ }
+ }
+
+ /* 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);
+ 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 = "W83877F",
+ };
+
+ 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 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;
+ pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
+ timeout);
+ }
+
+ if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) {
+ pr_err("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")) {
+ pr_err("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) {
+ 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 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");
Code Review / kvmfornfv.git / blobdiff