cregit-Linux how code gets into the kernel

Release 4.14 drivers/watchdog/wdt.c

Directory: drivers/watchdog
/*
 *      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_hw(io, int, ioport, 0);
MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
module_param_hw(irq, int, irq, 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); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)35100.00%1100.00%
Total35100.00%1100.00%


static void wdt_ctr_load(int ctr, int val) { outb_p(val&0xFF, WDT_COUNT0+ctr); outb_p(val>>8, WDT_COUNT0+ctr); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)34100.00%1100.00%
Total34100.00%1100.00%

/** * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Wim Van Sebroeck5053.76%120.00%
Alan Cox2324.73%240.00%
Linus Torvalds (pre-git)2021.51%240.00%
Total93100.00%5100.00%

/** * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Wim Van Sebroeck2145.65%120.00%
Alan Cox2043.48%120.00%
Linus Torvalds (pre-git)48.70%240.00%
Andrew Morton12.17%120.00%
Total46100.00%5100.00%

/** * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Wim Van Sebroeck3762.71%125.00%
Alan Cox2237.29%375.00%
Total59100.00%4100.00%

/** * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Wim Van Sebroeck36100.00%1100.00%
Total36100.00%1100.00%

/** * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Wim Van Sebroeck8563.91%125.00%
Alan Cox3929.32%250.00%
Linus Torvalds (pre-git)96.77%125.00%
Total133100.00%4100.00%

/** * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Alan Cox2652.00%266.67%
Wim Van Sebroeck2448.00%133.33%
Total50100.00%3100.00%


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"); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)4173.21%125.00%
Joe Perches610.71%125.00%
Wim Van Sebroeck58.93%125.00%
Alan Cox47.14%125.00%
Total56100.00%4100.00%

/** * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Alan Cox5544.72%225.00%
Linus Torvalds (pre-git)4637.40%112.50%
Joe Perches97.32%112.50%
Wim Van Sebroeck64.88%112.50%
Andrew Morton32.44%112.50%
Ilpo Järvinen21.63%112.50%
Eric W. Biedermann21.63%112.50%
Total123100.00%8100.00%

/** * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Dave Jones5760.64%114.29%
Linus Torvalds (pre-git)3436.17%342.86%
Al Viro11.06%114.29%
Wim Van Sebroeck11.06%114.29%
Andrew Morton11.06%114.29%
Total94100.00%7100.00%

/** * 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; } }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)8739.37%327.27%
Wim Van Sebroeck5022.62%327.27%
Dave Jones4821.72%218.18%
Al Viro2410.86%19.09%
Alan Cox125.43%218.18%
Total221100.00%11100.00%

/** * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)2457.14%125.00%
Linus Torvalds1228.57%250.00%
Wim Van Sebroeck614.29%125.00%
Total42100.00%4100.00%

/** * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Wim Van Sebroeck3566.04%133.33%
Linus Torvalds (pre-git)1630.19%133.33%
Joe Perches23.77%133.33%
Total53100.00%3100.00%

/** * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Wim Van Sebroeck3266.67%120.00%
Linus Torvalds (pre-git)1122.92%120.00%
Alan Cox36.25%120.00%
Dave Jones12.08%120.00%
Al Viro12.08%120.00%
Total48100.00%5100.00%

/** * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Wim Van Sebroeck1666.67%125.00%
Linus Torvalds625.00%125.00%
Dave Jones14.17%125.00%
Linus Torvalds (pre-git)14.17%125.00%
Total24100.00%4100.00%

/** * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Wim Van Sebroeck1578.95%133.33%
Linus Torvalds (pre-git)421.05%266.67%
Total19100.00%3100.00%

/** * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)3394.29%150.00%
Wim Van Sebroeck25.71%150.00%
Total35100.00%2100.00%

/* * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)3574.47%777.78%
Alan Cox612.77%111.11%
Wim Van Sebroeck612.77%111.11%
Total47100.00%9100.00%

/** * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)13448.03%753.85%
Wim Van Sebroeck7727.60%17.69%
Alan Cox4716.85%215.38%
Joe Perches186.45%17.69%
Andrew Morton20.72%17.69%
Yong Zhang10.36%17.69%
Total279100.00%13100.00%

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");

Overall Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)69536.16%1935.19%
Wim Van Sebroeck62232.36%712.96%
Alan Cox29415.30%35.56%
Dave Jones1527.91%59.26%
Joe Perches422.19%11.85%
Linus Torvalds361.87%47.41%
Al Viro261.35%11.85%
Andrew Morton221.14%59.26%
Art Haas120.62%11.85%
Arnaldo Carvalho de Melo60.31%11.85%
David Howells60.31%11.85%
Eric W. Biedermann20.10%11.85%
Ilpo Järvinen20.10%11.85%
Arjan van de Ven20.10%11.85%
Yong Zhang10.05%11.85%
Randy Dunlap10.05%11.85%
Andrey Panin10.05%11.85%
Total1922100.00%54100.00%
Directory: drivers/watchdog
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