663 lines · c
1// SPDX-License-Identifier: GPL-2.0+2/*3 * Industrial Computer Source WDT501 driver4 *5 * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,6 * All Rights Reserved.7 *8 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide9 * warranty for any of this software. This material is provided10 * "AS-IS" and at no charge.11 *12 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>13 *14 * Release 0.10.15 *16 * Fixes17 * Dave Gregorich : Modularisation and minor bugs18 * Alan Cox : Added the watchdog ioctl() stuff19 * Alan Cox : Fixed the reboot problem (as noted by20 * Matt Crocker).21 * Alan Cox : Added wdt= boot option22 * Alan Cox : Cleaned up copy/user stuff23 * Tim Hockin : Added insmod parameters, comment24 * cleanup, parameterized timeout25 * Tigran Aivazian : Restructured wdt_init() to handle26 * failures27 * Joel Becker : Added WDIOC_GET/SETTIMEOUT28 * Matt Domsch : Added nowayout module option29 */30 31#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt32 33#include <linux/interrupt.h>34#include <linux/module.h>35#include <linux/moduleparam.h>36#include <linux/types.h>37#include <linux/miscdevice.h>38#include <linux/watchdog.h>39#include <linux/fs.h>40#include <linux/ioport.h>41#include <linux/notifier.h>42#include <linux/reboot.h>43#include <linux/init.h>44#include <linux/io.h>45#include <linux/uaccess.h>46 47#include "wd501p.h"48 49static unsigned long wdt_is_open;50static char expect_close;51 52/*53 * Module parameters54 */55 56#define WD_TIMO 60 /* Default heartbeat = 60 seconds */57 58static int heartbeat = WD_TIMO;59static int wd_heartbeat;60module_param(heartbeat, int, 0);61MODULE_PARM_DESC(heartbeat,62 "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default="63 __MODULE_STRING(WD_TIMO) ")");64 65static bool nowayout = WATCHDOG_NOWAYOUT;66module_param(nowayout, bool, 0);67MODULE_PARM_DESC(nowayout,68 "Watchdog cannot be stopped once started (default="69 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");70 71/* You must set these - there is no sane way to probe for this board. */72static int io = 0x240;73static int irq = 11;74 75static DEFINE_SPINLOCK(wdt_lock);76 77module_param_hw(io, int, ioport, 0);78MODULE_PARM_DESC(io, "WDT io port (default=0x240)");79module_param_hw(irq, int, irq, 0);80MODULE_PARM_DESC(irq, "WDT irq (default=11)");81 82/* Support for the Fan Tachometer on the WDT501-P */83static int tachometer;84module_param(tachometer, int, 0);85MODULE_PARM_DESC(tachometer,86 "WDT501-P Fan Tachometer support (0=disable, default=0)");87 88static int type = 500;89module_param(type, int, 0);90MODULE_PARM_DESC(type,91 "WDT501-P Card type (500 or 501, default=500)");92 93/*94 * Programming support95 */96 97static void wdt_ctr_mode(int ctr, int mode)98{99 ctr <<= 6;100 ctr |= 0x30;101 ctr |= (mode << 1);102 outb_p(ctr, WDT_CR);103}104 105static void wdt_ctr_load(int ctr, int val)106{107 outb_p(val&0xFF, WDT_COUNT0+ctr);108 outb_p(val>>8, WDT_COUNT0+ctr);109}110 111/**112 * wdt_start:113 *114 * Start the watchdog driver.115 */116 117static int wdt_start(void)118{119 unsigned long flags;120 spin_lock_irqsave(&wdt_lock, flags);121 inb_p(WDT_DC); /* Disable watchdog */122 wdt_ctr_mode(0, 3); /* Program CTR0 for Mode 3:123 Square Wave Generator */124 wdt_ctr_mode(1, 2); /* Program CTR1 for Mode 2:125 Rate Generator */126 wdt_ctr_mode(2, 0); /* Program CTR2 for Mode 0:127 Pulse on Terminal Count */128 wdt_ctr_load(0, 8948); /* Count at 100Hz */129 wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */130 wdt_ctr_load(2, 65535); /* Length of reset pulse */131 outb_p(0, WDT_DC); /* Enable watchdog */132 spin_unlock_irqrestore(&wdt_lock, flags);133 return 0;134}135 136/**137 * wdt_stop:138 *139 * Stop the watchdog driver.140 */141 142static int wdt_stop(void)143{144 unsigned long flags;145 spin_lock_irqsave(&wdt_lock, flags);146 /* Turn the card off */147 inb_p(WDT_DC); /* Disable watchdog */148 wdt_ctr_load(2, 0); /* 0 length reset pulses now */149 spin_unlock_irqrestore(&wdt_lock, flags);150 return 0;151}152 153/**154 * wdt_ping:155 *156 * Reload counter one with the watchdog heartbeat. We don't bother157 * reloading the cascade counter.158 */159 160static void wdt_ping(void)161{162 unsigned long flags;163 spin_lock_irqsave(&wdt_lock, flags);164 /* Write a watchdog value */165 inb_p(WDT_DC); /* Disable watchdog */166 wdt_ctr_mode(1, 2); /* Re-Program CTR1 for Mode 2:167 Rate Generator */168 wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */169 outb_p(0, WDT_DC); /* Enable watchdog */170 spin_unlock_irqrestore(&wdt_lock, flags);171}172 173/**174 * wdt_set_heartbeat:175 * @t: the new heartbeat value that needs to be set.176 *177 * Set a new heartbeat value for the watchdog device. If the heartbeat178 * value is incorrect we keep the old value and return -EINVAL. If179 * successful we return 0.180 */181 182static int wdt_set_heartbeat(int t)183{184 if (t < 1 || t > 65535)185 return -EINVAL;186 187 heartbeat = t;188 wd_heartbeat = t * 100;189 return 0;190}191 192/**193 * wdt_get_status:194 *195 * Extract the status information from a WDT watchdog device. There are196 * several board variants so we have to know which bits are valid. Some197 * bits default to one and some to zero in order to be maximally painful.198 *199 * we then map the bits onto the status ioctl flags.200 */201 202static int wdt_get_status(void)203{204 unsigned char new_status;205 int status = 0;206 unsigned long flags;207 208 spin_lock_irqsave(&wdt_lock, flags);209 new_status = inb_p(WDT_SR);210 spin_unlock_irqrestore(&wdt_lock, flags);211 212 if (new_status & WDC_SR_ISOI0)213 status |= WDIOF_EXTERN1;214 if (new_status & WDC_SR_ISII1)215 status |= WDIOF_EXTERN2;216 if (type == 501) {217 if (!(new_status & WDC_SR_TGOOD))218 status |= WDIOF_OVERHEAT;219 if (!(new_status & WDC_SR_PSUOVER))220 status |= WDIOF_POWEROVER;221 if (!(new_status & WDC_SR_PSUUNDR))222 status |= WDIOF_POWERUNDER;223 if (tachometer) {224 if (!(new_status & WDC_SR_FANGOOD))225 status |= WDIOF_FANFAULT;226 }227 }228 return status;229}230 231/**232 * wdt_get_temperature:233 *234 * Reports the temperature in degrees Fahrenheit. The API is in235 * farenheit. It was designed by an imperial measurement luddite.236 */237 238static int wdt_get_temperature(void)239{240 unsigned short c;241 unsigned long flags;242 243 spin_lock_irqsave(&wdt_lock, flags);244 c = inb_p(WDT_RT);245 spin_unlock_irqrestore(&wdt_lock, flags);246 return (c * 11 / 15) + 7;247}248 249static void wdt_decode_501(int status)250{251 if (!(status & WDC_SR_TGOOD))252 pr_crit("Overheat alarm (%d)\n", inb_p(WDT_RT));253 if (!(status & WDC_SR_PSUOVER))254 pr_crit("PSU over voltage\n");255 if (!(status & WDC_SR_PSUUNDR))256 pr_crit("PSU under voltage\n");257}258 259/**260 * wdt_interrupt:261 * @irq: Interrupt number262 * @dev_id: Unused as we don't allow multiple devices.263 *264 * Handle an interrupt from the board. These are raised when the status265 * map changes in what the board considers an interesting way. That means266 * a failure condition occurring.267 */268 269static irqreturn_t wdt_interrupt(int irq, void *dev_id)270{271 /*272 * Read the status register see what is up and273 * then printk it.274 */275 unsigned char status;276 277 spin_lock(&wdt_lock);278 status = inb_p(WDT_SR);279 280 pr_crit("WDT status %d\n", status);281 282 if (type == 501) {283 wdt_decode_501(status);284 if (tachometer) {285 if (!(status & WDC_SR_FANGOOD))286 pr_crit("Possible fan fault\n");287 }288 }289 if (!(status & WDC_SR_WCCR)) {290#ifdef SOFTWARE_REBOOT291#ifdef ONLY_TESTING292 pr_crit("Would Reboot\n");293#else294 pr_crit("Initiating system reboot\n");295 emergency_restart();296#endif297#else298 pr_crit("Reset in 5ms\n");299#endif300 }301 spin_unlock(&wdt_lock);302 return IRQ_HANDLED;303}304 305 306/**307 * wdt_write:308 * @file: file handle to the watchdog309 * @buf: buffer to write (unused as data does not matter here310 * @count: count of bytes311 * @ppos: pointer to the position to write. No seeks allowed312 *313 * A write to a watchdog device is defined as a keepalive signal. Any314 * write of data will do, as we we don't define content meaning.315 */316 317static ssize_t wdt_write(struct file *file, const char __user *buf,318 size_t count, loff_t *ppos)319{320 if (count) {321 if (!nowayout) {322 size_t i;323 324 /* In case it was set long ago */325 expect_close = 0;326 327 for (i = 0; i != count; i++) {328 char c;329 if (get_user(c, buf + i))330 return -EFAULT;331 if (c == 'V')332 expect_close = 42;333 }334 }335 wdt_ping();336 }337 return count;338}339 340/**341 * wdt_ioctl:342 * @file: file handle to the device343 * @cmd: watchdog command344 * @arg: argument pointer345 *346 * The watchdog API defines a common set of functions for all watchdogs347 * according to their available features. We only actually usefully support348 * querying capabilities and current status.349 */350 351static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)352{353 void __user *argp = (void __user *)arg;354 int __user *p = argp;355 int new_heartbeat;356 int status;357 358 struct watchdog_info ident = {359 .options = WDIOF_SETTIMEOUT|360 WDIOF_MAGICCLOSE|361 WDIOF_KEEPALIVEPING,362 .firmware_version = 1,363 .identity = "WDT500/501",364 };365 366 /* Add options according to the card we have */367 ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);368 if (type == 501) {369 ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|370 WDIOF_POWEROVER);371 if (tachometer)372 ident.options |= WDIOF_FANFAULT;373 }374 375 switch (cmd) {376 case WDIOC_GETSUPPORT:377 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;378 case WDIOC_GETSTATUS:379 status = wdt_get_status();380 return put_user(status, p);381 case WDIOC_GETBOOTSTATUS:382 return put_user(0, p);383 case WDIOC_KEEPALIVE:384 wdt_ping();385 return 0;386 case WDIOC_SETTIMEOUT:387 if (get_user(new_heartbeat, p))388 return -EFAULT;389 if (wdt_set_heartbeat(new_heartbeat))390 return -EINVAL;391 wdt_ping();392 fallthrough;393 case WDIOC_GETTIMEOUT:394 return put_user(heartbeat, p);395 default:396 return -ENOTTY;397 }398}399 400/**401 * wdt_open:402 * @inode: inode of device403 * @file: file handle to device404 *405 * The watchdog device has been opened. The watchdog device is single406 * open and on opening we load the counters. Counter zero is a 100Hz407 * cascade, into counter 1 which downcounts to reboot. When the counter408 * triggers counter 2 downcounts the length of the reset pulse which409 * set set to be as long as possible.410 */411 412static int wdt_open(struct inode *inode, struct file *file)413{414 if (test_and_set_bit(0, &wdt_is_open))415 return -EBUSY;416 /*417 * Activate418 */419 wdt_start();420 return stream_open(inode, file);421}422 423/**424 * wdt_release:425 * @inode: inode to board426 * @file: file handle to board427 *428 * The watchdog has a configurable API. There is a religious dispute429 * between people who want their watchdog to be able to shut down and430 * those who want to be sure if the watchdog manager dies the machine431 * reboots. In the former case we disable the counters, in the latter432 * case you have to open it again very soon.433 */434 435static int wdt_release(struct inode *inode, struct file *file)436{437 if (expect_close == 42) {438 wdt_stop();439 clear_bit(0, &wdt_is_open);440 } else {441 pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");442 wdt_ping();443 }444 expect_close = 0;445 return 0;446}447 448/**449 * wdt_temp_read:450 * @file: file handle to the watchdog board451 * @buf: buffer to write 1 byte into452 * @count: length of buffer453 * @ptr: offset (no seek allowed)454 *455 * Temp_read reports the temperature in degrees Fahrenheit. The API is in456 * farenheit. It was designed by an imperial measurement luddite.457 */458 459static ssize_t wdt_temp_read(struct file *file, char __user *buf,460 size_t count, loff_t *ptr)461{462 int temperature = wdt_get_temperature();463 464 if (copy_to_user(buf, &temperature, 1))465 return -EFAULT;466 467 return 1;468}469 470/**471 * wdt_temp_open:472 * @inode: inode of device473 * @file: file handle to device474 *475 * The temperature device has been opened.476 */477 478static int wdt_temp_open(struct inode *inode, struct file *file)479{480 return stream_open(inode, file);481}482 483/**484 * wdt_temp_release:485 * @inode: inode to board486 * @file: file handle to board487 *488 * The temperature device has been closed.489 */490 491static int wdt_temp_release(struct inode *inode, struct file *file)492{493 return 0;494}495 496/**497 * wdt_notify_sys:498 * @this: our notifier block499 * @code: the event being reported500 * @unused: unused501 *502 * Our notifier is called on system shutdowns. We want to turn the card503 * off at reboot otherwise the machine will reboot again during memory504 * test or worse yet during the following fsck. This would suck, in fact505 * trust me - if it happens it does suck.506 */507 508static int wdt_notify_sys(struct notifier_block *this, unsigned long code,509 void *unused)510{511 if (code == SYS_DOWN || code == SYS_HALT)512 wdt_stop();513 return NOTIFY_DONE;514}515 516/*517 * Kernel Interfaces518 */519 520 521static const struct file_operations wdt_fops = {522 .owner = THIS_MODULE,523 .write = wdt_write,524 .unlocked_ioctl = wdt_ioctl,525 .compat_ioctl = compat_ptr_ioctl,526 .open = wdt_open,527 .release = wdt_release,528};529 530static struct miscdevice wdt_miscdev = {531 .minor = WATCHDOG_MINOR,532 .name = "watchdog",533 .fops = &wdt_fops,534};535 536static const struct file_operations wdt_temp_fops = {537 .owner = THIS_MODULE,538 .read = wdt_temp_read,539 .open = wdt_temp_open,540 .release = wdt_temp_release,541};542 543static struct miscdevice temp_miscdev = {544 .minor = TEMP_MINOR,545 .name = "temperature",546 .fops = &wdt_temp_fops,547};548 549/*550 * The WDT card needs to learn about soft shutdowns in order to551 * turn the timebomb registers off.552 */553 554static struct notifier_block wdt_notifier = {555 .notifier_call = wdt_notify_sys,556};557 558/**559 * wdt_exit:560 *561 * Unload the watchdog. You cannot do this with any file handles open.562 * If your watchdog is set to continue ticking on close and you unload563 * it, well it keeps ticking. We won't get the interrupt but the board564 * will not touch PC memory so all is fine. You just have to load a new565 * module in 60 seconds or reboot.566 */567 568static void __exit wdt_exit(void)569{570 misc_deregister(&wdt_miscdev);571 if (type == 501)572 misc_deregister(&temp_miscdev);573 unregister_reboot_notifier(&wdt_notifier);574 free_irq(irq, NULL);575 release_region(io, 8);576}577 578/**579 * wdt_init:580 *581 * Set up the WDT watchdog board. All we have to do is grab the582 * resources we require and bitch if anyone beat us to them.583 * The open() function will actually kick the board off.584 */585 586static int __init wdt_init(void)587{588 int ret;589 590 if (type != 500 && type != 501) {591 pr_err("unknown card type '%d'\n", type);592 return -ENODEV;593 }594 595 /* Check that the heartbeat value is within it's range;596 if not reset to the default */597 if (wdt_set_heartbeat(heartbeat)) {598 wdt_set_heartbeat(WD_TIMO);599 pr_info("heartbeat value must be 0 < heartbeat < 65536, using %d\n",600 WD_TIMO);601 }602 603 if (!request_region(io, 8, "wdt501p")) {604 pr_err("I/O address 0x%04x already in use\n", io);605 ret = -EBUSY;606 goto out;607 }608 609 ret = request_irq(irq, wdt_interrupt, 0, "wdt501p", NULL);610 if (ret) {611 pr_err("IRQ %d is not free\n", irq);612 goto outreg;613 }614 615 ret = register_reboot_notifier(&wdt_notifier);616 if (ret) {617 pr_err("cannot register reboot notifier (err=%d)\n", ret);618 goto outirq;619 }620 621 if (type == 501) {622 ret = misc_register(&temp_miscdev);623 if (ret) {624 pr_err("cannot register miscdev on minor=%d (err=%d)\n",625 TEMP_MINOR, ret);626 goto outrbt;627 }628 }629 630 ret = misc_register(&wdt_miscdev);631 if (ret) {632 pr_err("cannot register miscdev on minor=%d (err=%d)\n",633 WATCHDOG_MINOR, ret);634 goto outmisc;635 }636 637 pr_info("WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",638 io, irq, heartbeat, nowayout);639 if (type == 501)640 pr_info("Fan Tachometer is %s\n",641 tachometer ? "Enabled" : "Disabled");642 return 0;643 644outmisc:645 if (type == 501)646 misc_deregister(&temp_miscdev);647outrbt:648 unregister_reboot_notifier(&wdt_notifier);649outirq:650 free_irq(irq, NULL);651outreg:652 release_region(io, 8);653out:654 return ret;655}656 657module_init(wdt_init);658module_exit(wdt_exit);659 660MODULE_AUTHOR("Alan Cox");661MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");662MODULE_LICENSE("GPL");663