404 lines · c
1// SPDX-License-Identifier: GPL-2.0+2/*3 * SBC8360 Watchdog driver4 *5 * (c) Copyright 2005 Webcon, Inc.6 *7 * Based on ib700wdt.c, which is based on advantechwdt.c which is based8 * on acquirewdt.c which is based on wdt.c.9 *10 * (c) Copyright 2001 Charles Howes <chowes@vsol.net>11 *12 * Based on advantechwdt.c which is based on acquirewdt.c which13 * is based on wdt.c.14 *15 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>16 *17 * Based on acquirewdt.c which is based on wdt.c.18 * Original copyright messages:19 *20 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,21 * All Rights Reserved.22 *23 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide24 * warranty for any of this software. This material is provided25 * "AS-IS" and at no charge.26 *27 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>28 *29 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>30 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT31 * Added timeout module option to override default32 *33 */34 35#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt36 37#include <linux/module.h>38#include <linux/types.h>39#include <linux/miscdevice.h>40#include <linux/watchdog.h>41#include <linux/ioport.h>42#include <linux/delay.h>43#include <linux/notifier.h>44#include <linux/fs.h>45#include <linux/reboot.h>46#include <linux/init.h>47#include <linux/spinlock.h>48#include <linux/moduleparam.h>49#include <linux/io.h>50#include <linux/uaccess.h>51 52 53static unsigned long sbc8360_is_open;54static char expect_close;55 56/*57 *58 * Watchdog Timer Configuration59 *60 * The function of the watchdog timer is to reset the system automatically61 * and is defined at I/O port 0120H and 0121H. To enable the watchdog timer62 * and allow the system to reset, write appropriate values from the table63 * below to I/O port 0120H and 0121H. To disable the timer, write a zero64 * value to I/O port 0121H for the system to stop the watchdog function.65 *66 * The following describes how the timer should be programmed (according to67 * the vendor documentation)68 *69 * Enabling Watchdog:70 * MOV AX,000AH (enable, phase I)71 * MOV DX,0120H72 * OUT DX,AX73 * MOV AX,000BH (enable, phase II)74 * MOV DX,0120H75 * OUT DX,AX76 * MOV AX,000nH (set multiplier n, from 1-4)77 * MOV DX,0120H78 * OUT DX,AX79 * MOV AX,000mH (set base timer m, from 0-F)80 * MOV DX,0121H81 * OUT DX,AX82 *83 * Reset timer:84 * MOV AX,000mH (same as set base timer, above)85 * MOV DX,0121H86 * OUT DX,AX87 *88 * Disabling Watchdog:89 * MOV AX,0000H (a zero value)90 * MOV DX,0120H91 * OUT DX,AX92 *93 * Watchdog timeout configuration values:94 * N95 * M | 1 2 3 496 * --|----------------------------------97 * 0 | 0.5s 5s 50s 100s98 * 1 | 1s 10s 100s 200s99 * 2 | 1.5s 15s 150s 300s100 * 3 | 2s 20s 200s 400s101 * 4 | 2.5s 25s 250s 500s102 * 5 | 3s 30s 300s 600s103 * 6 | 3.5s 35s 350s 700s104 * 7 | 4s 40s 400s 800s105 * 8 | 4.5s 45s 450s 900s106 * 9 | 5s 50s 500s 1000s107 * A | 5.5s 55s 550s 1100s108 * B | 6s 60s 600s 1200s109 * C | 6.5s 65s 650s 1300s110 * D | 7s 70s 700s 1400s111 * E | 7.5s 75s 750s 1500s112 * F | 8s 80s 800s 1600s113 *114 * Another way to say the same things is:115 * For N=1, Timeout = (M+1) * 0.5s116 * For N=2, Timeout = (M+1) * 5s117 * For N=3, Timeout = (M+1) * 50s118 * For N=4, Timeout = (M+1) * 100s119 *120 */121 122static int wd_times[64][2] = {123 {0, 1}, /* 0 = 0.5s */124 {1, 1}, /* 1 = 1s */125 {2, 1}, /* 2 = 1.5s */126 {3, 1}, /* 3 = 2s */127 {4, 1}, /* 4 = 2.5s */128 {5, 1}, /* 5 = 3s */129 {6, 1}, /* 6 = 3.5s */130 {7, 1}, /* 7 = 4s */131 {8, 1}, /* 8 = 4.5s */132 {9, 1}, /* 9 = 5s */133 {0xA, 1}, /* 10 = 5.5s */134 {0xB, 1}, /* 11 = 6s */135 {0xC, 1}, /* 12 = 6.5s */136 {0xD, 1}, /* 13 = 7s */137 {0xE, 1}, /* 14 = 7.5s */138 {0xF, 1}, /* 15 = 8s */139 {0, 2}, /* 16 = 5s */140 {1, 2}, /* 17 = 10s */141 {2, 2}, /* 18 = 15s */142 {3, 2}, /* 19 = 20s */143 {4, 2}, /* 20 = 25s */144 {5, 2}, /* 21 = 30s */145 {6, 2}, /* 22 = 35s */146 {7, 2}, /* 23 = 40s */147 {8, 2}, /* 24 = 45s */148 {9, 2}, /* 25 = 50s */149 {0xA, 2}, /* 26 = 55s */150 {0xB, 2}, /* 27 = 60s */151 {0xC, 2}, /* 28 = 65s */152 {0xD, 2}, /* 29 = 70s */153 {0xE, 2}, /* 30 = 75s */154 {0xF, 2}, /* 31 = 80s */155 {0, 3}, /* 32 = 50s */156 {1, 3}, /* 33 = 100s */157 {2, 3}, /* 34 = 150s */158 {3, 3}, /* 35 = 200s */159 {4, 3}, /* 36 = 250s */160 {5, 3}, /* 37 = 300s */161 {6, 3}, /* 38 = 350s */162 {7, 3}, /* 39 = 400s */163 {8, 3}, /* 40 = 450s */164 {9, 3}, /* 41 = 500s */165 {0xA, 3}, /* 42 = 550s */166 {0xB, 3}, /* 43 = 600s */167 {0xC, 3}, /* 44 = 650s */168 {0xD, 3}, /* 45 = 700s */169 {0xE, 3}, /* 46 = 750s */170 {0xF, 3}, /* 47 = 800s */171 {0, 4}, /* 48 = 100s */172 {1, 4}, /* 49 = 200s */173 {2, 4}, /* 50 = 300s */174 {3, 4}, /* 51 = 400s */175 {4, 4}, /* 52 = 500s */176 {5, 4}, /* 53 = 600s */177 {6, 4}, /* 54 = 700s */178 {7, 4}, /* 55 = 800s */179 {8, 4}, /* 56 = 900s */180 {9, 4}, /* 57 = 1000s */181 {0xA, 4}, /* 58 = 1100s */182 {0xB, 4}, /* 59 = 1200s */183 {0xC, 4}, /* 60 = 1300s */184 {0xD, 4}, /* 61 = 1400s */185 {0xE, 4}, /* 62 = 1500s */186 {0xF, 4} /* 63 = 1600s */187};188 189#define SBC8360_ENABLE 0x120190#define SBC8360_BASETIME 0x121191 192static int timeout = 27;193static int wd_margin = 0xB;194static int wd_multiplier = 2;195static bool nowayout = WATCHDOG_NOWAYOUT;196 197module_param(timeout, int, 0);198MODULE_PARM_DESC(timeout, "Index into timeout table (0-63) (default=27 (60s))");199module_param(nowayout, bool, 0);200MODULE_PARM_DESC(nowayout,201 "Watchdog cannot be stopped once started (default="202 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");203 204/*205 * Kernel methods.206 */207 208/* Activate and pre-configure watchdog */209static void sbc8360_activate(void)210{211 /* Enable the watchdog */212 outb(0x0A, SBC8360_ENABLE);213 msleep_interruptible(100);214 outb(0x0B, SBC8360_ENABLE);215 msleep_interruptible(100);216 /* Set timeout multiplier */217 outb(wd_multiplier, SBC8360_ENABLE);218 msleep_interruptible(100);219 /* Nothing happens until first sbc8360_ping() */220}221 222/* Kernel pings watchdog */223static void sbc8360_ping(void)224{225 /* Write the base timer register */226 outb(wd_margin, SBC8360_BASETIME);227}228 229/* stop watchdog */230static void sbc8360_stop(void)231{232 /* De-activate the watchdog */233 outb(0, SBC8360_ENABLE);234}235 236/* Userspace pings kernel driver, or requests clean close */237static ssize_t sbc8360_write(struct file *file, const char __user *buf,238 size_t count, loff_t *ppos)239{240 if (count) {241 if (!nowayout) {242 size_t i;243 244 /* In case it was set long ago */245 expect_close = 0;246 247 for (i = 0; i != count; i++) {248 char c;249 if (get_user(c, buf + i))250 return -EFAULT;251 if (c == 'V')252 expect_close = 42;253 }254 }255 sbc8360_ping();256 }257 return count;258}259 260static int sbc8360_open(struct inode *inode, struct file *file)261{262 if (test_and_set_bit(0, &sbc8360_is_open))263 return -EBUSY;264 if (nowayout)265 __module_get(THIS_MODULE);266 267 /* Activate and ping once to start the countdown */268 sbc8360_activate();269 sbc8360_ping();270 return stream_open(inode, file);271}272 273static int sbc8360_close(struct inode *inode, struct file *file)274{275 if (expect_close == 42)276 sbc8360_stop();277 else278 pr_crit("SBC8360 device closed unexpectedly. SBC8360 will not stop!\n");279 280 clear_bit(0, &sbc8360_is_open);281 expect_close = 0;282 return 0;283}284 285/*286 * Notifier for system down287 */288 289static int sbc8360_notify_sys(struct notifier_block *this, unsigned long code,290 void *unused)291{292 if (code == SYS_DOWN || code == SYS_HALT)293 sbc8360_stop(); /* Disable the SBC8360 Watchdog */294 295 return NOTIFY_DONE;296}297 298/*299 * Kernel Interfaces300 */301 302static const struct file_operations sbc8360_fops = {303 .owner = THIS_MODULE,304 .write = sbc8360_write,305 .open = sbc8360_open,306 .release = sbc8360_close,307};308 309static struct miscdevice sbc8360_miscdev = {310 .minor = WATCHDOG_MINOR,311 .name = "watchdog",312 .fops = &sbc8360_fops,313};314 315/*316 * The SBC8360 needs to learn about soft shutdowns in order to317 * turn the timebomb registers off.318 */319 320static struct notifier_block sbc8360_notifier = {321 .notifier_call = sbc8360_notify_sys,322};323 324static int __init sbc8360_init(void)325{326 int res;327 unsigned long int mseconds = 60000;328 329 if (timeout < 0 || timeout > 63) {330 pr_err("Invalid timeout index (must be 0-63)\n");331 res = -EINVAL;332 goto out;333 }334 335 if (!request_region(SBC8360_ENABLE, 1, "SBC8360")) {336 pr_err("ENABLE method I/O %X is not available\n",337 SBC8360_ENABLE);338 res = -EIO;339 goto out;340 }341 if (!request_region(SBC8360_BASETIME, 1, "SBC8360")) {342 pr_err("BASETIME method I/O %X is not available\n",343 SBC8360_BASETIME);344 res = -EIO;345 goto out_nobasetimereg;346 }347 348 res = register_reboot_notifier(&sbc8360_notifier);349 if (res) {350 pr_err("Failed to register reboot notifier\n");351 goto out_noreboot;352 }353 354 res = misc_register(&sbc8360_miscdev);355 if (res) {356 pr_err("failed to register misc device\n");357 goto out_nomisc;358 }359 360 wd_margin = wd_times[timeout][0];361 wd_multiplier = wd_times[timeout][1];362 363 if (wd_multiplier == 1)364 mseconds = (wd_margin + 1) * 500;365 else if (wd_multiplier == 2)366 mseconds = (wd_margin + 1) * 5000;367 else if (wd_multiplier == 3)368 mseconds = (wd_margin + 1) * 50000;369 else if (wd_multiplier == 4)370 mseconds = (wd_margin + 1) * 100000;371 372 /* My kingdom for the ability to print "0.5 seconds" in the kernel! */373 pr_info("Timeout set at %ld ms\n", mseconds);374 375 return 0;376 377out_nomisc:378 unregister_reboot_notifier(&sbc8360_notifier);379out_noreboot:380 release_region(SBC8360_BASETIME, 1);381out_nobasetimereg:382 release_region(SBC8360_ENABLE, 1);383out:384 return res;385}386 387static void __exit sbc8360_exit(void)388{389 misc_deregister(&sbc8360_miscdev);390 unregister_reboot_notifier(&sbc8360_notifier);391 release_region(SBC8360_ENABLE, 1);392 release_region(SBC8360_BASETIME, 1);393}394 395module_init(sbc8360_init);396module_exit(sbc8360_exit);397 398MODULE_AUTHOR("Ian E. Morgan <imorgan@webcon.ca>");399MODULE_DESCRIPTION("SBC8360 watchdog driver");400MODULE_LICENSE("GPL");401MODULE_VERSION("1.01");402 403/* end of sbc8360.c */404