summaryrefslogtreecommitdiff
path: root/drivers/watchdog/wdt.c
diff options
context:
space:
mode:
authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /drivers/watchdog/wdt.c
Initial import
Diffstat (limited to 'drivers/watchdog/wdt.c')
-rw-r--r--drivers/watchdog/wdt.c667
1 files changed, 667 insertions, 0 deletions
diff --git a/drivers/watchdog/wdt.c b/drivers/watchdog/wdt.c
new file mode 100644
index 000000000..e0206b5b7
--- /dev/null
+++ b/drivers/watchdog/wdt.c
@@ -0,0 +1,667 @@
+/*
+ * Industrial Computer Source WDT501 driver
+ *
+ * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
+ * All Rights Reserved.
+ *
+ * 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>
+ *
+ * Release 0.10.
+ *
+ * Fixes
+ * Dave Gregorich : Modularisation and minor bugs
+ * Alan Cox : Added the watchdog ioctl() stuff
+ * Alan Cox : Fixed the reboot problem (as noted by
+ * Matt Crocker).
+ * Alan Cox : Added wdt= boot option
+ * Alan Cox : Cleaned up copy/user stuff
+ * Tim Hockin : Added insmod parameters, comment
+ * cleanup, parameterized timeout
+ * Tigran Aivazian : Restructured wdt_init() to handle
+ * failures
+ * Joel Becker : Added WDIOC_GET/SETTIMEOUT
+ * Matt Domsch : Added nowayout module option
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.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>
+
+#include "wd501p.h"
+
+static unsigned long wdt_is_open;
+static char expect_close;
+
+/*
+ * Module parameters
+ */
+
+#define WD_TIMO 60 /* Default heartbeat = 60 seconds */
+
+static int heartbeat = WD_TIMO;
+static int wd_heartbeat;
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat,
+ "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default="
+ __MODULE_STRING(WD_TIMO) ")");
+
+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) ")");
+
+/* You must set these - there is no sane way to probe for this board. */
+static int io = 0x240;
+static int irq = 11;
+
+static DEFINE_SPINLOCK(wdt_lock);
+
+module_param(io, int, 0);
+MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
+module_param(irq, int, 0);
+MODULE_PARM_DESC(irq, "WDT irq (default=11)");
+
+/* Support for the Fan Tachometer on the WDT501-P */
+static int tachometer;
+module_param(tachometer, int, 0);
+MODULE_PARM_DESC(tachometer,
+ "WDT501-P Fan Tachometer support (0=disable, default=0)");
+
+static int type = 500;
+module_param(type, int, 0);
+MODULE_PARM_DESC(type,
+ "WDT501-P Card type (500 or 501, default=500)");
+
+/*
+ * Programming support
+ */
+
+static void wdt_ctr_mode(int ctr, int mode)
+{
+ ctr <<= 6;
+ ctr |= 0x30;
+ ctr |= (mode << 1);
+ outb_p(ctr, WDT_CR);
+}
+
+static void wdt_ctr_load(int ctr, int val)
+{
+ outb_p(val&0xFF, WDT_COUNT0+ctr);
+ outb_p(val>>8, WDT_COUNT0+ctr);
+}
+
+/**
+ * wdt_start:
+ *
+ * Start the watchdog driver.
+ */
+
+static int wdt_start(void)
+{
+ unsigned long flags;
+ spin_lock_irqsave(&wdt_lock, flags);
+ inb_p(WDT_DC); /* Disable watchdog */
+ wdt_ctr_mode(0, 3); /* Program CTR0 for Mode 3:
+ Square Wave Generator */
+ wdt_ctr_mode(1, 2); /* Program CTR1 for Mode 2:
+ Rate Generator */
+ wdt_ctr_mode(2, 0); /* Program CTR2 for Mode 0:
+ Pulse on Terminal Count */
+ wdt_ctr_load(0, 8948); /* Count at 100Hz */
+ wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */
+ wdt_ctr_load(2, 65535); /* Length of reset pulse */
+ outb_p(0, WDT_DC); /* Enable watchdog */
+ spin_unlock_irqrestore(&wdt_lock, flags);
+ return 0;
+}
+
+/**
+ * wdt_stop:
+ *
+ * Stop the watchdog driver.
+ */
+
+static int wdt_stop(void)
+{
+ unsigned long flags;
+ spin_lock_irqsave(&wdt_lock, flags);
+ /* Turn the card off */
+ inb_p(WDT_DC); /* Disable watchdog */
+ wdt_ctr_load(2, 0); /* 0 length reset pulses now */
+ spin_unlock_irqrestore(&wdt_lock, flags);
+ return 0;
+}
+
+/**
+ * wdt_ping:
+ *
+ * Reload counter one with the watchdog heartbeat. We don't bother
+ * reloading the cascade counter.
+ */
+
+static void wdt_ping(void)
+{
+ unsigned long flags;
+ spin_lock_irqsave(&wdt_lock, flags);
+ /* Write a watchdog value */
+ inb_p(WDT_DC); /* Disable watchdog */
+ wdt_ctr_mode(1, 2); /* Re-Program CTR1 for Mode 2:
+ Rate Generator */
+ wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */
+ outb_p(0, WDT_DC); /* Enable watchdog */
+ spin_unlock_irqrestore(&wdt_lock, flags);
+}
+
+/**
+ * wdt_set_heartbeat:
+ * @t: the new heartbeat value that needs to be set.
+ *
+ * Set a new heartbeat value for the watchdog device. If the heartbeat
+ * value is incorrect we keep the old value and return -EINVAL. If
+ * successful we return 0.
+ */
+
+static int wdt_set_heartbeat(int t)
+{
+ if (t < 1 || t > 65535)
+ return -EINVAL;
+
+ heartbeat = t;
+ wd_heartbeat = t * 100;
+ return 0;
+}
+
+/**
+ * wdt_get_status:
+ *
+ * Extract the status information from a WDT watchdog device. There are
+ * several board variants so we have to know which bits are valid. Some
+ * bits default to one and some to zero in order to be maximally painful.
+ *
+ * we then map the bits onto the status ioctl flags.
+ */
+
+static int wdt_get_status(void)
+{
+ unsigned char new_status;
+ int status = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&wdt_lock, flags);
+ new_status = inb_p(WDT_SR);
+ spin_unlock_irqrestore(&wdt_lock, flags);
+
+ if (new_status & WDC_SR_ISOI0)
+ status |= WDIOF_EXTERN1;
+ if (new_status & WDC_SR_ISII1)
+ status |= WDIOF_EXTERN2;
+ if (type == 501) {
+ if (!(new_status & WDC_SR_TGOOD))
+ status |= WDIOF_OVERHEAT;
+ if (!(new_status & WDC_SR_PSUOVER))
+ status |= WDIOF_POWEROVER;
+ if (!(new_status & WDC_SR_PSUUNDR))
+ status |= WDIOF_POWERUNDER;
+ if (tachometer) {
+ if (!(new_status & WDC_SR_FANGOOD))
+ status |= WDIOF_FANFAULT;
+ }
+ }
+ return status;
+}
+
+/**
+ * wdt_get_temperature:
+ *
+ * Reports the temperature in degrees Fahrenheit. The API is in
+ * farenheit. It was designed by an imperial measurement luddite.
+ */
+
+static int wdt_get_temperature(void)
+{
+ unsigned short c;
+ unsigned long flags;
+
+ spin_lock_irqsave(&wdt_lock, flags);
+ c = inb_p(WDT_RT);
+ spin_unlock_irqrestore(&wdt_lock, flags);
+ return (c * 11 / 15) + 7;
+}
+
+static void wdt_decode_501(int status)
+{
+ if (!(status & WDC_SR_TGOOD))
+ pr_crit("Overheat alarm (%d)\n", inb_p(WDT_RT));
+ if (!(status & WDC_SR_PSUOVER))
+ pr_crit("PSU over voltage\n");
+ if (!(status & WDC_SR_PSUUNDR))
+ pr_crit("PSU under voltage\n");
+}
+
+/**
+ * wdt_interrupt:
+ * @irq: Interrupt number
+ * @dev_id: Unused as we don't allow multiple devices.
+ *
+ * Handle an interrupt from the board. These are raised when the status
+ * map changes in what the board considers an interesting way. That means
+ * a failure condition occurring.
+ */
+
+static irqreturn_t wdt_interrupt(int irq, void *dev_id)
+{
+ /*
+ * Read the status register see what is up and
+ * then printk it.
+ */
+ unsigned char status;
+
+ spin_lock(&wdt_lock);
+ status = inb_p(WDT_SR);
+
+ pr_crit("WDT status %d\n", status);
+
+ if (type == 501) {
+ wdt_decode_501(status);
+ if (tachometer) {
+ if (!(status & WDC_SR_FANGOOD))
+ pr_crit("Possible fan fault\n");
+ }
+ }
+ if (!(status & WDC_SR_WCCR)) {
+#ifdef SOFTWARE_REBOOT
+#ifdef ONLY_TESTING
+ pr_crit("Would Reboot\n");
+#else
+ pr_crit("Initiating system reboot\n");
+ emergency_restart();
+#endif
+#else
+ pr_crit("Reset in 5ms\n");
+#endif
+ }
+ spin_unlock(&wdt_lock);
+ return IRQ_HANDLED;
+}
+
+
+/**
+ * wdt_write:
+ * @file: file handle to the watchdog
+ * @buf: buffer to write (unused as data does not matter here
+ * @count: count of bytes
+ * @ppos: pointer to the position to write. No seeks allowed
+ *
+ * A write to a watchdog device is defined as a keepalive signal. Any
+ * write of data will do, as we we don't define content meaning.
+ */
+
+static ssize_t wdt_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ if (count) {
+ if (!nowayout) {
+ size_t i;
+
+ /* In case it was set long ago */
+ expect_close = 0;
+
+ for (i = 0; i != count; i++) {
+ char c;
+ if (get_user(c, buf + i))
+ return -EFAULT;
+ if (c == 'V')
+ expect_close = 42;
+ }
+ }
+ wdt_ping();
+ }
+ return count;
+}
+
+/**
+ * wdt_ioctl:
+ * @file: file handle to the device
+ * @cmd: watchdog command
+ * @arg: argument pointer
+ *
+ * The watchdog API defines a common set of functions for all watchdogs
+ * according to their available features. We only actually usefully support
+ * querying capabilities and current status.
+ */
+
+static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ int new_heartbeat;
+ int status;
+
+ struct watchdog_info ident = {
+ .options = WDIOF_SETTIMEOUT|
+ WDIOF_MAGICCLOSE|
+ WDIOF_KEEPALIVEPING,
+ .firmware_version = 1,
+ .identity = "WDT500/501",
+ };
+
+ /* Add options according to the card we have */
+ ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);
+ if (type == 501) {
+ ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|
+ WDIOF_POWEROVER);
+ if (tachometer)
+ ident.options |= WDIOF_FANFAULT;
+ }
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+ case WDIOC_GETSTATUS:
+ status = wdt_get_status();
+ return put_user(status, p);
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(0, p);
+ case WDIOC_KEEPALIVE:
+ wdt_ping();
+ return 0;
+ case WDIOC_SETTIMEOUT:
+ if (get_user(new_heartbeat, p))
+ return -EFAULT;
+ if (wdt_set_heartbeat(new_heartbeat))
+ return -EINVAL;
+ wdt_ping();
+ /* Fall */
+ case WDIOC_GETTIMEOUT:
+ return put_user(heartbeat, p);
+ default:
+ return -ENOTTY;
+ }
+}
+
+/**
+ * wdt_open:
+ * @inode: inode of device
+ * @file: file handle to device
+ *
+ * The watchdog device has been opened. The watchdog device is single
+ * open and on opening we load the counters. Counter zero is a 100Hz
+ * cascade, into counter 1 which downcounts to reboot. When the counter
+ * triggers counter 2 downcounts the length of the reset pulse which
+ * set set to be as long as possible.
+ */
+
+static int wdt_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(0, &wdt_is_open))
+ return -EBUSY;
+ /*
+ * Activate
+ */
+ wdt_start();
+ return nonseekable_open(inode, file);
+}
+
+/**
+ * wdt_release:
+ * @inode: inode to board
+ * @file: file handle to board
+ *
+ * The watchdog has a configurable API. There is a religious dispute
+ * between people who want their watchdog to be able to shut down and
+ * those who want to be sure if the watchdog manager dies the machine
+ * reboots. In the former case we disable the counters, in the latter
+ * case you have to open it again very soon.
+ */
+
+static int wdt_release(struct inode *inode, struct file *file)
+{
+ if (expect_close == 42) {
+ wdt_stop();
+ clear_bit(0, &wdt_is_open);
+ } else {
+ pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");
+ wdt_ping();
+ }
+ expect_close = 0;
+ return 0;
+}
+
+/**
+ * wdt_temp_read:
+ * @file: file handle to the watchdog board
+ * @buf: buffer to write 1 byte into
+ * @count: length of buffer
+ * @ptr: offset (no seek allowed)
+ *
+ * Temp_read reports the temperature in degrees Fahrenheit. The API is in
+ * farenheit. It was designed by an imperial measurement luddite.
+ */
+
+static ssize_t wdt_temp_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ptr)
+{
+ int temperature = wdt_get_temperature();
+
+ if (copy_to_user(buf, &temperature, 1))
+ return -EFAULT;
+
+ return 1;
+}
+
+/**
+ * wdt_temp_open:
+ * @inode: inode of device
+ * @file: file handle to device
+ *
+ * The temperature device has been opened.
+ */
+
+static int wdt_temp_open(struct inode *inode, struct file *file)
+{
+ return nonseekable_open(inode, file);
+}
+
+/**
+ * wdt_temp_release:
+ * @inode: inode to board
+ * @file: file handle to board
+ *
+ * The temperature device has been closed.
+ */
+
+static int wdt_temp_release(struct inode *inode, struct file *file)
+{
+ return 0;
+}
+
+/**
+ * notify_sys:
+ * @this: our notifier block
+ * @code: the event being reported
+ * @unused: unused
+ *
+ * Our notifier is called on system shutdowns. We want to turn the card
+ * off at reboot otherwise the machine will reboot again during memory
+ * test or worse yet during the following fsck. This would suck, in fact
+ * trust me - if it happens it does suck.
+ */
+
+static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
+ void *unused)
+{
+ if (code == SYS_DOWN || code == SYS_HALT)
+ wdt_stop();
+ return NOTIFY_DONE;
+}
+
+/*
+ * Kernel Interfaces
+ */
+
+
+static const struct file_operations wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = wdt_write,
+ .unlocked_ioctl = wdt_ioctl,
+ .open = wdt_open,
+ .release = wdt_release,
+};
+
+static struct miscdevice wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &wdt_fops,
+};
+
+static const struct file_operations wdt_temp_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .read = wdt_temp_read,
+ .open = wdt_temp_open,
+ .release = wdt_temp_release,
+};
+
+static struct miscdevice temp_miscdev = {
+ .minor = TEMP_MINOR,
+ .name = "temperature",
+ .fops = &wdt_temp_fops,
+};
+
+/*
+ * The WDT card 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,
+};
+
+/**
+ * cleanup_module:
+ *
+ * Unload the watchdog. You cannot do this with any file handles open.
+ * If your watchdog is set to continue ticking on close and you unload
+ * it, well it keeps ticking. We won't get the interrupt but the board
+ * will not touch PC memory so all is fine. You just have to load a new
+ * module in 60 seconds or reboot.
+ */
+
+static void __exit wdt_exit(void)
+{
+ misc_deregister(&wdt_miscdev);
+ if (type == 501)
+ misc_deregister(&temp_miscdev);
+ unregister_reboot_notifier(&wdt_notifier);
+ free_irq(irq, NULL);
+ release_region(io, 8);
+}
+
+/**
+ * wdt_init:
+ *
+ * Set up the WDT watchdog board. All we have to do is grab the
+ * resources we require and bitch if anyone beat us to them.
+ * The open() function will actually kick the board off.
+ */
+
+static int __init wdt_init(void)
+{
+ int ret;
+
+ if (type != 500 && type != 501) {
+ pr_err("unknown card type '%d'\n", type);
+ return -ENODEV;
+ }
+
+ /* Check that the heartbeat value is within it's range;
+ if not reset to the default */
+ if (wdt_set_heartbeat(heartbeat)) {
+ wdt_set_heartbeat(WD_TIMO);
+ pr_info("heartbeat value must be 0 < heartbeat < 65536, using %d\n",
+ WD_TIMO);
+ }
+
+ if (!request_region(io, 8, "wdt501p")) {
+ pr_err("I/O address 0x%04x already in use\n", io);
+ ret = -EBUSY;
+ goto out;
+ }
+
+ ret = request_irq(irq, wdt_interrupt, 0, "wdt501p", NULL);
+ if (ret) {
+ pr_err("IRQ %d is not free\n", irq);
+ goto outreg;
+ }
+
+ ret = register_reboot_notifier(&wdt_notifier);
+ if (ret) {
+ pr_err("cannot register reboot notifier (err=%d)\n", ret);
+ goto outirq;
+ }
+
+ if (type == 501) {
+ ret = misc_register(&temp_miscdev);
+ if (ret) {
+ pr_err("cannot register miscdev on minor=%d (err=%d)\n",
+ TEMP_MINOR, ret);
+ goto outrbt;
+ }
+ }
+
+ ret = misc_register(&wdt_miscdev);
+ if (ret) {
+ pr_err("cannot register miscdev on minor=%d (err=%d)\n",
+ WATCHDOG_MINOR, ret);
+ goto outmisc;
+ }
+
+ pr_info("WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
+ io, irq, heartbeat, nowayout);
+ if (type == 501)
+ pr_info("Fan Tachometer is %s\n",
+ tachometer ? "Enabled" : "Disabled");
+ return 0;
+
+outmisc:
+ if (type == 501)
+ misc_deregister(&temp_miscdev);
+outrbt:
+ unregister_reboot_notifier(&wdt_notifier);
+outirq:
+ free_irq(irq, NULL);
+outreg:
+ release_region(io, 8);
+out:
+ return ret;
+}
+
+module_init(wdt_init);
+module_exit(wdt_exit);
+
+MODULE_AUTHOR("Alan Cox");
+MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");
+MODULE_LICENSE("GPL");