--- /dev/null
+/*
+ * 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");
Code Review / kvmfornfv.git / blobdiff