1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * MixCom Watchdog: A Simple Hardware Watchdog Device 4 * Based on Softdog driver by Alan Cox and PC Watchdog driver by Ken Hollis 5 * 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 version 12 * 13 * Version 0.2 (99/06/16): 14 * - added kernel timer watchdog ping after close 15 * since the hardware does not support watchdog shutdown 16 * 17 * Version 0.3 (99/06/21): 18 * - added WDIOC_GETSTATUS and WDIOC_GETSUPPORT ioctl calls 19 * 20 * Version 0.3.1 (99/06/22): 21 * - allow module removal while internal timer is active, 22 * print warning about probable reset 23 * 24 * Version 0.4 (99/11/15): 25 * - support for one more type board 26 * 27 * Version 0.5 (2001/12/14) Matt Domsch <Matt_Domsch@dell.com> 28 * - added nowayout module option to override 29 * CONFIG_WATCHDOG_NOWAYOUT 30 * 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 API 35 */ 36 37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 38 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 #include <linux/stringify.h> 56 57 /* 58 * We have two types of cards that can be probed: 59 * 1) The Mixcom cards: these cards can be found at addresses 60 * 0x180, 0x280, 0x380 with an additional offset of 0xc10. 61 * (Or 0xd90, 0xe90, 0xf90). 62 * 2) The FlashCOM cards: these cards can be set up at 63 * 0x300 -> 0x378, in 0x8 jumps with an offset of 0x04. 64 * (Or 0x304 -> 0x37c in 0x8 jumps). 65 * Each card has it's own ID. 66 */ 67 #define MIXCOM_ID 0x11 68 #define FLASHCOM_ID 0x18 69 static struct { 70 int ioport; 71 int id; 72 } mixcomwd_io_info[] = { 73 /* The Mixcom cards */ 74 {0x0d90, MIXCOM_ID}, 75 {0x0e90, MIXCOM_ID}, 76 {0x0f90, MIXCOM_ID}, 77 /* The FlashCOM cards */ 78 {0x0304, FLASHCOM_ID}, 79 {0x030c, FLASHCOM_ID}, 80 {0x0314, FLASHCOM_ID}, 81 {0x031c, FLASHCOM_ID}, 82 {0x0324, FLASHCOM_ID}, 83 {0x032c, FLASHCOM_ID}, 84 {0x0334, FLASHCOM_ID}, 85 {0x033c, FLASHCOM_ID}, 86 {0x0344, FLASHCOM_ID}, 87 {0x034c, FLASHCOM_ID}, 88 {0x0354, FLASHCOM_ID}, 89 {0x035c, FLASHCOM_ID}, 90 {0x0364, FLASHCOM_ID}, 91 {0x036c, FLASHCOM_ID}, 92 {0x0374, FLASHCOM_ID}, 93 {0x037c, FLASHCOM_ID}, 94 /* The end of the list */ 95 {0x0000, 0}, 96 }; 97 98 static void mixcomwd_timerfun(struct timer_list *unused); 99 100 static unsigned long mixcomwd_opened; /* long req'd for setbit --RR */ 101 102 static int watchdog_port; 103 static int mixcomwd_timer_alive; 104 static DEFINE_TIMER(mixcomwd_timer, mixcomwd_timerfun); 105 static char expect_close; 106 107 static bool nowayout = WATCHDOG_NOWAYOUT; 108 module_param(nowayout, bool, 0); 109 MODULE_PARM_DESC(nowayout, 110 "Watchdog cannot be stopped once started (default=" 111 __stringify(WATCHDOG_NOWAYOUT) ")"); 112 113 static void mixcomwd_ping(void) 114 { 115 outb_p(55, watchdog_port); 116 return; 117 } 118 119 static void mixcomwd_timerfun(struct timer_list *unused) 120 { 121 mixcomwd_ping(); 122 mod_timer(&mixcomwd_timer, jiffies + 5 * HZ); 123 } 124 125 /* 126 * Allow only one person to hold it open 127 */ 128 129 static int mixcomwd_open(struct inode *inode, struct file *file) 130 { 131 if (test_and_set_bit(0, &mixcomwd_opened)) 132 return -EBUSY; 133 134 mixcomwd_ping(); 135 136 if (nowayout) 137 /* 138 * fops_get() code via open() has already done 139 * a try_module_get() so it is safe to do the 140 * __module_get(). 141 */ 142 __module_get(THIS_MODULE); 143 else { 144 if (mixcomwd_timer_alive) { 145 timer_delete(&mixcomwd_timer); 146 mixcomwd_timer_alive = 0; 147 } 148 } 149 return stream_open(inode, file); 150 } 151 152 static int mixcomwd_release(struct inode *inode, struct file *file) 153 { 154 if (expect_close == 42) { 155 if (mixcomwd_timer_alive) { 156 pr_err("release called while internal timer alive\n"); 157 return -EBUSY; 158 } 159 mixcomwd_timer_alive = 1; 160 mod_timer(&mixcomwd_timer, jiffies + 5 * HZ); 161 } else 162 pr_crit("WDT device closed unexpectedly. WDT will not stop!\n"); 163 164 clear_bit(0, &mixcomwd_opened); 165 expect_close = 0; 166 return 0; 167 } 168 169 170 static ssize_t mixcomwd_write(struct file *file, const char __user *data, 171 size_t len, loff_t *ppos) 172 { 173 if (len) { 174 if (!nowayout) { 175 size_t i; 176 177 /* In case it was set long ago */ 178 expect_close = 0; 179 180 for (i = 0; i != len; i++) { 181 char c; 182 if (get_user(c, data + i)) 183 return -EFAULT; 184 if (c == 'V') 185 expect_close = 42; 186 } 187 } 188 mixcomwd_ping(); 189 } 190 return len; 191 } 192 193 static long mixcomwd_ioctl(struct file *file, 194 unsigned int cmd, unsigned long arg) 195 { 196 void __user *argp = (void __user *)arg; 197 int __user *p = argp; 198 int status; 199 static const struct watchdog_info ident = { 200 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 201 .firmware_version = 1, 202 .identity = "MixCOM watchdog", 203 }; 204 205 switch (cmd) { 206 case WDIOC_GETSUPPORT: 207 if (copy_to_user(argp, &ident, sizeof(ident))) 208 return -EFAULT; 209 break; 210 case WDIOC_GETSTATUS: 211 status = mixcomwd_opened; 212 if (!nowayout) 213 status |= mixcomwd_timer_alive; 214 return put_user(status, p); 215 case WDIOC_GETBOOTSTATUS: 216 return put_user(0, p); 217 case WDIOC_KEEPALIVE: 218 mixcomwd_ping(); 219 break; 220 default: 221 return -ENOTTY; 222 } 223 return 0; 224 } 225 226 static const struct file_operations mixcomwd_fops = { 227 .owner = THIS_MODULE, 228 .write = mixcomwd_write, 229 .unlocked_ioctl = mixcomwd_ioctl, 230 .compat_ioctl = compat_ptr_ioctl, 231 .open = mixcomwd_open, 232 .release = mixcomwd_release, 233 }; 234 235 static struct miscdevice mixcomwd_miscdev = { 236 .minor = WATCHDOG_MINOR, 237 .name = "watchdog", 238 .fops = &mixcomwd_fops, 239 }; 240 241 static int __init checkcard(int port, int card_id) 242 { 243 int id; 244 245 if (!request_region(port, 1, "MixCOM watchdog")) 246 return 0; 247 248 id = inb_p(port); 249 if (card_id == MIXCOM_ID) 250 id &= 0x3f; 251 252 if (id != card_id) { 253 release_region(port, 1); 254 return 0; 255 } 256 return 1; 257 } 258 259 static int __init mixcomwd_init(void) 260 { 261 int i, ret, found = 0; 262 263 for (i = 0; !found && mixcomwd_io_info[i].ioport != 0; i++) { 264 if (checkcard(mixcomwd_io_info[i].ioport, 265 mixcomwd_io_info[i].id)) { 266 found = 1; 267 watchdog_port = mixcomwd_io_info[i].ioport; 268 } 269 } 270 271 if (!found) { 272 pr_err("No card detected, or port not available\n"); 273 return -ENODEV; 274 } 275 276 ret = misc_register(&mixcomwd_miscdev); 277 if (ret) { 278 pr_err("cannot register miscdev on minor=%d (err=%d)\n", 279 WATCHDOG_MINOR, ret); 280 goto error_misc_register_watchdog; 281 } 282 283 pr_info("MixCOM watchdog driver v%s, watchdog port at 0x%3x\n", 284 VERSION, watchdog_port); 285 286 return 0; 287 288 error_misc_register_watchdog: 289 release_region(watchdog_port, 1); 290 watchdog_port = 0x0000; 291 return ret; 292 } 293 294 static void __exit mixcomwd_exit(void) 295 { 296 if (!nowayout) { 297 if (mixcomwd_timer_alive) { 298 pr_warn("I quit now, hardware will probably reboot!\n"); 299 timer_delete_sync(&mixcomwd_timer); 300 mixcomwd_timer_alive = 0; 301 } 302 } 303 misc_deregister(&mixcomwd_miscdev); 304 release_region(watchdog_port, 1); 305 } 306 307 module_init(mixcomwd_init); 308 module_exit(mixcomwd_exit); 309 310 MODULE_AUTHOR("Gergely Madarasz <gorgo@itc.hu>"); 311 MODULE_DESCRIPTION("MixCom Watchdog driver"); 312 MODULE_VERSION(VERSION); 313 MODULE_LICENSE("GPL"); 314