313 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * MixCom Watchdog: A Simple Hardware Watchdog Device4 * Based on Softdog driver by Alan Cox and PC Watchdog driver by Ken Hollis5 *6 * Author: Gergely Madarasz <gorgo@itc.hu>7 *8 * Copyright (c) 1999 ITConsult-Pro Co. <info@itc.hu>9 *10 * Version 0.1 (99/04/15):11 * - first version12 *13 * Version 0.2 (99/06/16):14 * - added kernel timer watchdog ping after close15 * since the hardware does not support watchdog shutdown16 *17 * Version 0.3 (99/06/21):18 * - added WDIOC_GETSTATUS and WDIOC_GETSUPPORT ioctl calls19 *20 * Version 0.3.1 (99/06/22):21 * - allow module removal while internal timer is active,22 * print warning about probable reset23 *24 * Version 0.4 (99/11/15):25 * - support for one more type board26 *27 * Version 0.5 (2001/12/14) Matt Domsch <Matt_Domsch@dell.com>28 * - added nowayout module option to override29 * CONFIG_WATCHDOG_NOWAYOUT30 *31 * Version 0.6 (2002/04/12): Rob Radez <rob@osinvestor.com>32 * - make mixcomwd_opened unsigned,33 * removed lock_kernel/unlock_kernel from mixcomwd_release,34 * modified ioctl a bit to conform to API35 */36 37#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt38 39#define VERSION "0.6"40#define WATCHDOG_NAME "mixcomwd"41 42#include <linux/module.h>43#include <linux/moduleparam.h>44#include <linux/types.h>45#include <linux/miscdevice.h>46#include <linux/ioport.h>47#include <linux/watchdog.h>48#include <linux/fs.h>49#include <linux/reboot.h>50#include <linux/init.h>51#include <linux/jiffies.h>52#include <linux/timer.h>53#include <linux/uaccess.h>54#include <linux/io.h>55 56/*57 * We have two types of cards that can be probed:58 * 1) The Mixcom cards: these cards can be found at addresses59 * 0x180, 0x280, 0x380 with an additional offset of 0xc10.60 * (Or 0xd90, 0xe90, 0xf90).61 * 2) The FlashCOM cards: these cards can be set up at62 * 0x300 -> 0x378, in 0x8 jumps with an offset of 0x04.63 * (Or 0x304 -> 0x37c in 0x8 jumps).64 * Each card has it's own ID.65 */66#define MIXCOM_ID 0x1167#define FLASHCOM_ID 0x1868static struct {69 int ioport;70 int id;71} mixcomwd_io_info[] = {72 /* The Mixcom cards */73 {0x0d90, MIXCOM_ID},74 {0x0e90, MIXCOM_ID},75 {0x0f90, MIXCOM_ID},76 /* The FlashCOM cards */77 {0x0304, FLASHCOM_ID},78 {0x030c, FLASHCOM_ID},79 {0x0314, FLASHCOM_ID},80 {0x031c, FLASHCOM_ID},81 {0x0324, FLASHCOM_ID},82 {0x032c, FLASHCOM_ID},83 {0x0334, FLASHCOM_ID},84 {0x033c, FLASHCOM_ID},85 {0x0344, FLASHCOM_ID},86 {0x034c, FLASHCOM_ID},87 {0x0354, FLASHCOM_ID},88 {0x035c, FLASHCOM_ID},89 {0x0364, FLASHCOM_ID},90 {0x036c, FLASHCOM_ID},91 {0x0374, FLASHCOM_ID},92 {0x037c, FLASHCOM_ID},93 /* The end of the list */94 {0x0000, 0},95};96 97static void mixcomwd_timerfun(struct timer_list *unused);98 99static unsigned long mixcomwd_opened; /* long req'd for setbit --RR */100 101static int watchdog_port;102static int mixcomwd_timer_alive;103static DEFINE_TIMER(mixcomwd_timer, mixcomwd_timerfun);104static char expect_close;105 106static bool nowayout = WATCHDOG_NOWAYOUT;107module_param(nowayout, bool, 0);108MODULE_PARM_DESC(nowayout,109 "Watchdog cannot be stopped once started (default="110 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");111 112static void mixcomwd_ping(void)113{114 outb_p(55, watchdog_port);115 return;116}117 118static void mixcomwd_timerfun(struct timer_list *unused)119{120 mixcomwd_ping();121 mod_timer(&mixcomwd_timer, jiffies + 5 * HZ);122}123 124/*125 * Allow only one person to hold it open126 */127 128static int mixcomwd_open(struct inode *inode, struct file *file)129{130 if (test_and_set_bit(0, &mixcomwd_opened))131 return -EBUSY;132 133 mixcomwd_ping();134 135 if (nowayout)136 /*137 * fops_get() code via open() has already done138 * a try_module_get() so it is safe to do the139 * __module_get().140 */141 __module_get(THIS_MODULE);142 else {143 if (mixcomwd_timer_alive) {144 del_timer(&mixcomwd_timer);145 mixcomwd_timer_alive = 0;146 }147 }148 return stream_open(inode, file);149}150 151static int mixcomwd_release(struct inode *inode, struct file *file)152{153 if (expect_close == 42) {154 if (mixcomwd_timer_alive) {155 pr_err("release called while internal timer alive\n");156 return -EBUSY;157 }158 mixcomwd_timer_alive = 1;159 mod_timer(&mixcomwd_timer, jiffies + 5 * HZ);160 } else161 pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");162 163 clear_bit(0, &mixcomwd_opened);164 expect_close = 0;165 return 0;166}167 168 169static ssize_t mixcomwd_write(struct file *file, const char __user *data,170 size_t len, loff_t *ppos)171{172 if (len) {173 if (!nowayout) {174 size_t i;175 176 /* In case it was set long ago */177 expect_close = 0;178 179 for (i = 0; i != len; i++) {180 char c;181 if (get_user(c, data + i))182 return -EFAULT;183 if (c == 'V')184 expect_close = 42;185 }186 }187 mixcomwd_ping();188 }189 return len;190}191 192static long mixcomwd_ioctl(struct file *file,193 unsigned int cmd, unsigned long arg)194{195 void __user *argp = (void __user *)arg;196 int __user *p = argp;197 int status;198 static const struct watchdog_info ident = {199 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,200 .firmware_version = 1,201 .identity = "MixCOM watchdog",202 };203 204 switch (cmd) {205 case WDIOC_GETSUPPORT:206 if (copy_to_user(argp, &ident, sizeof(ident)))207 return -EFAULT;208 break;209 case WDIOC_GETSTATUS:210 status = mixcomwd_opened;211 if (!nowayout)212 status |= mixcomwd_timer_alive;213 return put_user(status, p);214 case WDIOC_GETBOOTSTATUS:215 return put_user(0, p);216 case WDIOC_KEEPALIVE:217 mixcomwd_ping();218 break;219 default:220 return -ENOTTY;221 }222 return 0;223}224 225static const struct file_operations mixcomwd_fops = {226 .owner = THIS_MODULE,227 .write = mixcomwd_write,228 .unlocked_ioctl = mixcomwd_ioctl,229 .compat_ioctl = compat_ptr_ioctl,230 .open = mixcomwd_open,231 .release = mixcomwd_release,232};233 234static struct miscdevice mixcomwd_miscdev = {235 .minor = WATCHDOG_MINOR,236 .name = "watchdog",237 .fops = &mixcomwd_fops,238};239 240static int __init checkcard(int port, int card_id)241{242 int id;243 244 if (!request_region(port, 1, "MixCOM watchdog"))245 return 0;246 247 id = inb_p(port);248 if (card_id == MIXCOM_ID)249 id &= 0x3f;250 251 if (id != card_id) {252 release_region(port, 1);253 return 0;254 }255 return 1;256}257 258static int __init mixcomwd_init(void)259{260 int i, ret, found = 0;261 262 for (i = 0; !found && mixcomwd_io_info[i].ioport != 0; i++) {263 if (checkcard(mixcomwd_io_info[i].ioport,264 mixcomwd_io_info[i].id)) {265 found = 1;266 watchdog_port = mixcomwd_io_info[i].ioport;267 }268 }269 270 if (!found) {271 pr_err("No card detected, or port not available\n");272 return -ENODEV;273 }274 275 ret = misc_register(&mixcomwd_miscdev);276 if (ret) {277 pr_err("cannot register miscdev on minor=%d (err=%d)\n",278 WATCHDOG_MINOR, ret);279 goto error_misc_register_watchdog;280 }281 282 pr_info("MixCOM watchdog driver v%s, watchdog port at 0x%3x\n",283 VERSION, watchdog_port);284 285 return 0;286 287error_misc_register_watchdog:288 release_region(watchdog_port, 1);289 watchdog_port = 0x0000;290 return ret;291}292 293static void __exit mixcomwd_exit(void)294{295 if (!nowayout) {296 if (mixcomwd_timer_alive) {297 pr_warn("I quit now, hardware will probably reboot!\n");298 del_timer_sync(&mixcomwd_timer);299 mixcomwd_timer_alive = 0;300 }301 }302 misc_deregister(&mixcomwd_miscdev);303 release_region(watchdog_port, 1);304}305 306module_init(mixcomwd_init);307module_exit(mixcomwd_exit);308 309MODULE_AUTHOR("Gergely Madarasz <gorgo@itc.hu>");310MODULE_DESCRIPTION("MixCom Watchdog driver");311MODULE_VERSION(VERSION);312MODULE_LICENSE("GPL");313