1 /* 2 * SBC8360 Watchdog driver 3 * 4 * (c) Copyright 2005 Webcon, Inc. 5 * 6 * Based on ib700wdt.c, which is based on advantechwdt.c which is based 7 * on acquirewdt.c which is based on wdt.c. 8 * 9 * (c) Copyright 2001 Charles Howes <chowes@vsol.net> 10 * 11 * Based on advantechwdt.c which is based on acquirewdt.c which 12 * is based on wdt.c. 13 * 14 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl> 15 * 16 * Based on acquirewdt.c which is based on wdt.c. 17 * Original copyright messages: 18 * 19 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>, 20 * All Rights Reserved. 21 * 22 * This program is free software; you can redistribute it and/or 23 * modify it under the terms of the GNU General Public License 24 * as published by the Free Software Foundation; either version 25 * 2 of the License, or (at your option) any later version. 26 * 27 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide 28 * warranty for any of this software. This material is provided 29 * "AS-IS" and at no charge. 30 * 31 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> 32 * 33 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> 34 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT 35 * Added timeout module option to override default 36 * 37 */ 38 39 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 40 41 #include <linux/module.h> 42 #include <linux/types.h> 43 #include <linux/miscdevice.h> 44 #include <linux/watchdog.h> 45 #include <linux/ioport.h> 46 #include <linux/delay.h> 47 #include <linux/notifier.h> 48 #include <linux/fs.h> 49 #include <linux/reboot.h> 50 #include <linux/init.h> 51 #include <linux/spinlock.h> 52 #include <linux/moduleparam.h> 53 #include <linux/io.h> 54 #include <linux/uaccess.h> 55 56 57 static unsigned long sbc8360_is_open; 58 static char expect_close; 59 60 /* 61 * 62 * Watchdog Timer Configuration 63 * 64 * The function of the watchdog timer is to reset the system automatically 65 * and is defined at I/O port 0120H and 0121H. To enable the watchdog timer 66 * and allow the system to reset, write appropriate values from the table 67 * below to I/O port 0120H and 0121H. To disable the timer, write a zero 68 * value to I/O port 0121H for the system to stop the watchdog function. 69 * 70 * The following describes how the timer should be programmed (according to 71 * the vendor documentation) 72 * 73 * Enabling Watchdog: 74 * MOV AX,000AH (enable, phase I) 75 * MOV DX,0120H 76 * OUT DX,AX 77 * MOV AX,000BH (enable, phase II) 78 * MOV DX,0120H 79 * OUT DX,AX 80 * MOV AX,000nH (set multiplier n, from 1-4) 81 * MOV DX,0120H 82 * OUT DX,AX 83 * MOV AX,000mH (set base timer m, from 0-F) 84 * MOV DX,0121H 85 * OUT DX,AX 86 * 87 * Reset timer: 88 * MOV AX,000mH (same as set base timer, above) 89 * MOV DX,0121H 90 * OUT DX,AX 91 * 92 * Disabling Watchdog: 93 * MOV AX,0000H (a zero value) 94 * MOV DX,0120H 95 * OUT DX,AX 96 * 97 * Watchdog timeout configuration values: 98 * N 99 * M | 1 2 3 4 100 * --|---------------------------------- 101 * 0 | 0.5s 5s 50s 100s 102 * 1 | 1s 10s 100s 200s 103 * 2 | 1.5s 15s 150s 300s 104 * 3 | 2s 20s 200s 400s 105 * 4 | 2.5s 25s 250s 500s 106 * 5 | 3s 30s 300s 600s 107 * 6 | 3.5s 35s 350s 700s 108 * 7 | 4s 40s 400s 800s 109 * 8 | 4.5s 45s 450s 900s 110 * 9 | 5s 50s 500s 1000s 111 * A | 5.5s 55s 550s 1100s 112 * B | 6s 60s 600s 1200s 113 * C | 6.5s 65s 650s 1300s 114 * D | 7s 70s 700s 1400s 115 * E | 7.5s 75s 750s 1500s 116 * F | 8s 80s 800s 1600s 117 * 118 * Another way to say the same things is: 119 * For N=1, Timeout = (M+1) * 0.5s 120 * For N=2, Timeout = (M+1) * 5s 121 * For N=3, Timeout = (M+1) * 50s 122 * For N=4, Timeout = (M+1) * 100s 123 * 124 */ 125 126 static int wd_times[64][2] = { 127 {0, 1}, /* 0 = 0.5s */ 128 {1, 1}, /* 1 = 1s */ 129 {2, 1}, /* 2 = 1.5s */ 130 {3, 1}, /* 3 = 2s */ 131 {4, 1}, /* 4 = 2.5s */ 132 {5, 1}, /* 5 = 3s */ 133 {6, 1}, /* 6 = 3.5s */ 134 {7, 1}, /* 7 = 4s */ 135 {8, 1}, /* 8 = 4.5s */ 136 {9, 1}, /* 9 = 5s */ 137 {0xA, 1}, /* 10 = 5.5s */ 138 {0xB, 1}, /* 11 = 6s */ 139 {0xC, 1}, /* 12 = 6.5s */ 140 {0xD, 1}, /* 13 = 7s */ 141 {0xE, 1}, /* 14 = 7.5s */ 142 {0xF, 1}, /* 15 = 8s */ 143 {0, 2}, /* 16 = 5s */ 144 {1, 2}, /* 17 = 10s */ 145 {2, 2}, /* 18 = 15s */ 146 {3, 2}, /* 19 = 20s */ 147 {4, 2}, /* 20 = 25s */ 148 {5, 2}, /* 21 = 30s */ 149 {6, 2}, /* 22 = 35s */ 150 {7, 2}, /* 23 = 40s */ 151 {8, 2}, /* 24 = 45s */ 152 {9, 2}, /* 25 = 50s */ 153 {0xA, 2}, /* 26 = 55s */ 154 {0xB, 2}, /* 27 = 60s */ 155 {0xC, 2}, /* 28 = 65s */ 156 {0xD, 2}, /* 29 = 70s */ 157 {0xE, 2}, /* 30 = 75s */ 158 {0xF, 2}, /* 31 = 80s */ 159 {0, 3}, /* 32 = 50s */ 160 {1, 3}, /* 33 = 100s */ 161 {2, 3}, /* 34 = 150s */ 162 {3, 3}, /* 35 = 200s */ 163 {4, 3}, /* 36 = 250s */ 164 {5, 3}, /* 37 = 300s */ 165 {6, 3}, /* 38 = 350s */ 166 {7, 3}, /* 39 = 400s */ 167 {8, 3}, /* 40 = 450s */ 168 {9, 3}, /* 41 = 500s */ 169 {0xA, 3}, /* 42 = 550s */ 170 {0xB, 3}, /* 43 = 600s */ 171 {0xC, 3}, /* 44 = 650s */ 172 {0xD, 3}, /* 45 = 700s */ 173 {0xE, 3}, /* 46 = 750s */ 174 {0xF, 3}, /* 47 = 800s */ 175 {0, 4}, /* 48 = 100s */ 176 {1, 4}, /* 49 = 200s */ 177 {2, 4}, /* 50 = 300s */ 178 {3, 4}, /* 51 = 400s */ 179 {4, 4}, /* 52 = 500s */ 180 {5, 4}, /* 53 = 600s */ 181 {6, 4}, /* 54 = 700s */ 182 {7, 4}, /* 55 = 800s */ 183 {8, 4}, /* 56 = 900s */ 184 {9, 4}, /* 57 = 1000s */ 185 {0xA, 4}, /* 58 = 1100s */ 186 {0xB, 4}, /* 59 = 1200s */ 187 {0xC, 4}, /* 60 = 1300s */ 188 {0xD, 4}, /* 61 = 1400s */ 189 {0xE, 4}, /* 62 = 1500s */ 190 {0xF, 4} /* 63 = 1600s */ 191 }; 192 193 #define SBC8360_ENABLE 0x120 194 #define SBC8360_BASETIME 0x121 195 196 static int timeout = 27; 197 static int wd_margin = 0xB; 198 static int wd_multiplier = 2; 199 static bool nowayout = WATCHDOG_NOWAYOUT; 200 201 module_param(timeout, int, 0); 202 MODULE_PARM_DESC(timeout, "Index into timeout table (0-63) (default=27 (60s))"); 203 module_param(nowayout, bool, 0); 204 MODULE_PARM_DESC(nowayout, 205 "Watchdog cannot be stopped once started (default=" 206 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 207 208 /* 209 * Kernel methods. 210 */ 211 212 /* Activate and pre-configure watchdog */ 213 static void sbc8360_activate(void) 214 { 215 /* Enable the watchdog */ 216 outb(0x0A, SBC8360_ENABLE); 217 msleep_interruptible(100); 218 outb(0x0B, SBC8360_ENABLE); 219 msleep_interruptible(100); 220 /* Set timeout multiplier */ 221 outb(wd_multiplier, SBC8360_ENABLE); 222 msleep_interruptible(100); 223 /* Nothing happens until first sbc8360_ping() */ 224 } 225 226 /* Kernel pings watchdog */ 227 static void sbc8360_ping(void) 228 { 229 /* Write the base timer register */ 230 outb(wd_margin, SBC8360_BASETIME); 231 } 232 233 /* stop watchdog */ 234 static void sbc8360_stop(void) 235 { 236 /* De-activate the watchdog */ 237 outb(0, SBC8360_ENABLE); 238 } 239 240 /* Userspace pings kernel driver, or requests clean close */ 241 static ssize_t sbc8360_write(struct file *file, const char __user *buf, 242 size_t count, loff_t *ppos) 243 { 244 if (count) { 245 if (!nowayout) { 246 size_t i; 247 248 /* In case it was set long ago */ 249 expect_close = 0; 250 251 for (i = 0; i != count; i++) { 252 char c; 253 if (get_user(c, buf + i)) 254 return -EFAULT; 255 if (c == 'V') 256 expect_close = 42; 257 } 258 } 259 sbc8360_ping(); 260 } 261 return count; 262 } 263 264 static int sbc8360_open(struct inode *inode, struct file *file) 265 { 266 if (test_and_set_bit(0, &sbc8360_is_open)) 267 return -EBUSY; 268 if (nowayout) 269 __module_get(THIS_MODULE); 270 271 /* Activate and ping once to start the countdown */ 272 sbc8360_activate(); 273 sbc8360_ping(); 274 return stream_open(inode, file); 275 } 276 277 static int sbc8360_close(struct inode *inode, struct file *file) 278 { 279 if (expect_close == 42) 280 sbc8360_stop(); 281 else 282 pr_crit("SBC8360 device closed unexpectedly. SBC8360 will not stop!\n"); 283 284 clear_bit(0, &sbc8360_is_open); 285 expect_close = 0; 286 return 0; 287 } 288 289 /* 290 * Notifier for system down 291 */ 292 293 static int sbc8360_notify_sys(struct notifier_block *this, unsigned long code, 294 void *unused) 295 { 296 if (code == SYS_DOWN || code == SYS_HALT) 297 sbc8360_stop(); /* Disable the SBC8360 Watchdog */ 298 299 return NOTIFY_DONE; 300 } 301 302 /* 303 * Kernel Interfaces 304 */ 305 306 static const struct file_operations sbc8360_fops = { 307 .owner = THIS_MODULE, 308 .llseek = no_llseek, 309 .write = sbc8360_write, 310 .open = sbc8360_open, 311 .release = sbc8360_close, 312 }; 313 314 static struct miscdevice sbc8360_miscdev = { 315 .minor = WATCHDOG_MINOR, 316 .name = "watchdog", 317 .fops = &sbc8360_fops, 318 }; 319 320 /* 321 * The SBC8360 needs to learn about soft shutdowns in order to 322 * turn the timebomb registers off. 323 */ 324 325 static struct notifier_block sbc8360_notifier = { 326 .notifier_call = sbc8360_notify_sys, 327 }; 328 329 static int __init sbc8360_init(void) 330 { 331 int res; 332 unsigned long int mseconds = 60000; 333 334 if (timeout < 0 || timeout > 63) { 335 pr_err("Invalid timeout index (must be 0-63)\n"); 336 res = -EINVAL; 337 goto out; 338 } 339 340 if (!request_region(SBC8360_ENABLE, 1, "SBC8360")) { 341 pr_err("ENABLE method I/O %X is not available\n", 342 SBC8360_ENABLE); 343 res = -EIO; 344 goto out; 345 } 346 if (!request_region(SBC8360_BASETIME, 1, "SBC8360")) { 347 pr_err("BASETIME method I/O %X is not available\n", 348 SBC8360_BASETIME); 349 res = -EIO; 350 goto out_nobasetimereg; 351 } 352 353 res = register_reboot_notifier(&sbc8360_notifier); 354 if (res) { 355 pr_err("Failed to register reboot notifier\n"); 356 goto out_noreboot; 357 } 358 359 res = misc_register(&sbc8360_miscdev); 360 if (res) { 361 pr_err("failed to register misc device\n"); 362 goto out_nomisc; 363 } 364 365 wd_margin = wd_times[timeout][0]; 366 wd_multiplier = wd_times[timeout][1]; 367 368 if (wd_multiplier == 1) 369 mseconds = (wd_margin + 1) * 500; 370 else if (wd_multiplier == 2) 371 mseconds = (wd_margin + 1) * 5000; 372 else if (wd_multiplier == 3) 373 mseconds = (wd_margin + 1) * 50000; 374 else if (wd_multiplier == 4) 375 mseconds = (wd_margin + 1) * 100000; 376 377 /* My kingdom for the ability to print "0.5 seconds" in the kernel! */ 378 pr_info("Timeout set at %ld ms\n", mseconds); 379 380 return 0; 381 382 out_nomisc: 383 unregister_reboot_notifier(&sbc8360_notifier); 384 out_noreboot: 385 release_region(SBC8360_BASETIME, 1); 386 out_nobasetimereg: 387 release_region(SBC8360_ENABLE, 1); 388 out: 389 return res; 390 } 391 392 static void __exit sbc8360_exit(void) 393 { 394 misc_deregister(&sbc8360_miscdev); 395 unregister_reboot_notifier(&sbc8360_notifier); 396 release_region(SBC8360_ENABLE, 1); 397 release_region(SBC8360_BASETIME, 1); 398 } 399 400 module_init(sbc8360_init); 401 module_exit(sbc8360_exit); 402 403 MODULE_AUTHOR("Ian E. Morgan <imorgan@webcon.ca>"); 404 MODULE_DESCRIPTION("SBC8360 watchdog driver"); 405 MODULE_LICENSE("GPL"); 406 MODULE_VERSION("1.01"); 407 408 /* end of sbc8360.c */ 409