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#include <linux/module.h> 40#include <linux/types.h> 41#include <linux/miscdevice.h> 42#include <linux/watchdog.h> 43#include <linux/ioport.h> 44#include <linux/delay.h> 45#include <linux/notifier.h> 46#include <linux/fs.h> 47#include <linux/reboot.h> 48#include <linux/init.h> 49#include <linux/spinlock.h> 50#include <linux/moduleparam.h> 51#include <linux/io.h> 52#include <linux/uaccess.h> 53 54#include <asm/system.h> 55 56static unsigned long sbc8360_is_open; 57static char expect_close; 58 59#define PFX "sbc8360: " 60 61/* 62 * 63 * Watchdog Timer Configuration 64 * 65 * The function of the watchdog timer is to reset the system automatically 66 * and is defined at I/O port 0120H and 0121H. To enable the watchdog timer 67 * and allow the system to reset, write appropriate values from the table 68 * below to I/O port 0120H and 0121H. To disable the timer, write a zero 69 * value to I/O port 0121H for the system to stop the watchdog function. 70 * 71 * The following describes how the timer should be programmed (according to 72 * the vendor documentation) 73 * 74 * Enabling Watchdog: 75 * MOV AX,000AH (enable, phase I) 76 * MOV DX,0120H 77 * OUT DX,AX 78 * MOV AX,000BH (enable, phase II) 79 * MOV DX,0120H 80 * OUT DX,AX 81 * MOV AX,000nH (set multiplier n, from 1-4) 82 * MOV DX,0120H 83 * OUT DX,AX 84 * MOV AX,000mH (set base timer m, from 0-F) 85 * MOV DX,0121H 86 * OUT DX,AX 87 * 88 * Reset timer: 89 * MOV AX,000mH (same as set base timer, above) 90 * MOV DX,0121H 91 * OUT DX,AX 92 * 93 * Disabling Watchdog: 94 * MOV AX,0000H (a zero value) 95 * MOV DX,0120H 96 * OUT DX,AX 97 * 98 * Watchdog timeout configuration values: 99 * N 100 * M | 1 2 3 4 101 * --|---------------------------------- 102 * 0 | 0.5s 5s 50s 100s 103 * 1 | 1s 10s 100s 200s 104 * 2 | 1.5s 15s 150s 300s 105 * 3 | 2s 20s 200s 400s 106 * 4 | 2.5s 25s 250s 500s 107 * 5 | 3s 30s 300s 600s 108 * 6 | 3.5s 35s 350s 700s 109 * 7 | 4s 40s 400s 800s 110 * 8 | 4.5s 45s 450s 900s 111 * 9 | 5s 50s 500s 1000s 112 * A | 5.5s 55s 550s 1100s 113 * B | 6s 60s 600s 1200s 114 * C | 6.5s 65s 650s 1300s 115 * D | 7s 70s 700s 1400s 116 * E | 7.5s 75s 750s 1500s 117 * F | 8s 80s 800s 1600s 118 * 119 * Another way to say the same things is: 120 * For N=1, Timeout = (M+1) * 0.5s 121 * For N=2, Timeout = (M+1) * 5s 122 * For N=3, Timeout = (M+1) * 50s 123 * For N=4, Timeout = (M+1) * 100s 124 * 125 */ 126 127static int wd_times[64][2] = { 128 {0, 1}, /* 0 = 0.5s */ 129 {1, 1}, /* 1 = 1s */ 130 {2, 1}, /* 2 = 1.5s */ 131 {3, 1}, /* 3 = 2s */ 132 {4, 1}, /* 4 = 2.5s */ 133 {5, 1}, /* 5 = 3s */ 134 {6, 1}, /* 6 = 3.5s */ 135 {7, 1}, /* 7 = 4s */ 136 {8, 1}, /* 8 = 4.5s */ 137 {9, 1}, /* 9 = 5s */ 138 {0xA, 1}, /* 10 = 5.5s */ 139 {0xB, 1}, /* 11 = 6s */ 140 {0xC, 1}, /* 12 = 6.5s */ 141 {0xD, 1}, /* 13 = 7s */ 142 {0xE, 1}, /* 14 = 7.5s */ 143 {0xF, 1}, /* 15 = 8s */ 144 {0, 2}, /* 16 = 5s */ 145 {1, 2}, /* 17 = 10s */ 146 {2, 2}, /* 18 = 15s */ 147 {3, 2}, /* 19 = 20s */ 148 {4, 2}, /* 20 = 25s */ 149 {5, 2}, /* 21 = 30s */ 150 {6, 2}, /* 22 = 35s */ 151 {7, 2}, /* 23 = 40s */ 152 {8, 2}, /* 24 = 45s */ 153 {9, 2}, /* 25 = 50s */ 154 {0xA, 2}, /* 26 = 55s */ 155 {0xB, 2}, /* 27 = 60s */ 156 {0xC, 2}, /* 28 = 65s */ 157 {0xD, 2}, /* 29 = 70s */ 158 {0xE, 2}, /* 30 = 75s */ 159 {0xF, 2}, /* 31 = 80s */ 160 {0, 3}, /* 32 = 50s */ 161 {1, 3}, /* 33 = 100s */ 162 {2, 3}, /* 34 = 150s */ 163 {3, 3}, /* 35 = 200s */ 164 {4, 3}, /* 36 = 250s */ 165 {5, 3}, /* 37 = 300s */ 166 {6, 3}, /* 38 = 350s */ 167 {7, 3}, /* 39 = 400s */ 168 {8, 3}, /* 40 = 450s */ 169 {9, 3}, /* 41 = 500s */ 170 {0xA, 3}, /* 42 = 550s */ 171 {0xB, 3}, /* 43 = 600s */ 172 {0xC, 3}, /* 44 = 650s */ 173 {0xD, 3}, /* 45 = 700s */ 174 {0xE, 3}, /* 46 = 750s */ 175 {0xF, 3}, /* 47 = 800s */ 176 {0, 4}, /* 48 = 100s */ 177 {1, 4}, /* 49 = 200s */ 178 {2, 4}, /* 50 = 300s */ 179 {3, 4}, /* 51 = 400s */ 180 {4, 4}, /* 52 = 500s */ 181 {5, 4}, /* 53 = 600s */ 182 {6, 4}, /* 54 = 700s */ 183 {7, 4}, /* 55 = 800s */ 184 {8, 4}, /* 56 = 900s */ 185 {9, 4}, /* 57 = 1000s */ 186 {0xA, 4}, /* 58 = 1100s */ 187 {0xB, 4}, /* 59 = 1200s */ 188 {0xC, 4}, /* 60 = 1300s */ 189 {0xD, 4}, /* 61 = 1400s */ 190 {0xE, 4}, /* 62 = 1500s */ 191 {0xF, 4} /* 63 = 1600s */ 192}; 193 194#define SBC8360_ENABLE 0x120 195#define SBC8360_BASETIME 0x121 196 197static int timeout = 27; 198static int wd_margin = 0xB; 199static int wd_multiplier = 2; 200static int nowayout = WATCHDOG_NOWAYOUT; 201 202module_param(timeout, int, 0); 203MODULE_PARM_DESC(timeout, "Index into timeout table (0-63) (default=27 (60s))"); 204module_param(nowayout, int, 0); 205MODULE_PARM_DESC(nowayout, 206 "Watchdog cannot be stopped once started (default=" 207 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 208 209/* 210 * Kernel methods. 211 */ 212 213/* Activate and pre-configure watchdog */ 214static void sbc8360_activate(void) 215{ 216 /* Enable the watchdog */ 217 outb(0x0A, SBC8360_ENABLE); 218 msleep_interruptible(100); 219 outb(0x0B, SBC8360_ENABLE); 220 msleep_interruptible(100); 221 /* Set timeout multiplier */ 222 outb(wd_multiplier, SBC8360_ENABLE); 223 msleep_interruptible(100); 224 /* Nothing happens until first sbc8360_ping() */ 225} 226 227/* Kernel pings watchdog */ 228static void sbc8360_ping(void) 229{ 230 /* Write the base timer register */ 231 outb(wd_margin, SBC8360_BASETIME); 232} 233 234/* stop watchdog */ 235static void sbc8360_stop(void) 236{ 237 /* De-activate the watchdog */ 238 outb(0, SBC8360_ENABLE); 239} 240 241/* Userspace pings kernel driver, or requests clean close */ 242static ssize_t sbc8360_write(struct file *file, const char __user *buf, 243 size_t count, loff_t *ppos) 244{ 245 if (count) { 246 if (!nowayout) { 247 size_t i; 248 249 /* In case it was set long ago */ 250 expect_close = 0; 251 252 for (i = 0; i != count; i++) { 253 char c; 254 if (get_user(c, buf + i)) 255 return -EFAULT; 256 if (c == 'V') 257 expect_close = 42; 258 } 259 } 260 sbc8360_ping(); 261 } 262 return count; 263} 264 265static int sbc8360_open(struct inode *inode, struct file *file) 266{ 267 if (test_and_set_bit(0, &sbc8360_is_open)) 268 return -EBUSY; 269 if (nowayout) 270 __module_get(THIS_MODULE); 271 272 /* Activate and ping once to start the countdown */ 273 sbc8360_activate(); 274 sbc8360_ping(); 275 return nonseekable_open(inode, file); 276} 277 278static int sbc8360_close(struct inode *inode, struct file *file) 279{ 280 if (expect_close == 42) 281 sbc8360_stop(); 282 else 283 printk(KERN_CRIT PFX "SBC8360 device closed unexpectedly. " 284 "SBC8360 will not stop!\n"); 285 286 clear_bit(0, &sbc8360_is_open); 287 expect_close = 0; 288 return 0; 289} 290 291/* 292 * Notifier for system down 293 */ 294 295static int sbc8360_notify_sys(struct notifier_block *this, unsigned long code, 296 void *unused) 297{ 298 if (code == SYS_DOWN || code == SYS_HALT) 299 sbc8360_stop(); /* Disable the SBC8360 Watchdog */ 300 301 return NOTIFY_DONE; 302} 303 304/* 305 * Kernel Interfaces 306 */ 307 308static const struct file_operations sbc8360_fops = { 309 .owner = THIS_MODULE, 310 .llseek = no_llseek, 311 .write = sbc8360_write, 312 .open = sbc8360_open, 313 .release = sbc8360_close, 314}; 315 316static struct miscdevice sbc8360_miscdev = { 317 .minor = WATCHDOG_MINOR, 318 .name = "watchdog", 319 .fops = &sbc8360_fops, 320}; 321 322/* 323 * The SBC8360 needs to learn about soft shutdowns in order to 324 * turn the timebomb registers off. 325 */ 326 327static struct notifier_block sbc8360_notifier = { 328 .notifier_call = sbc8360_notify_sys, 329}; 330 331static int __init sbc8360_init(void) 332{ 333 int res; 334 unsigned long int mseconds = 60000; 335 336 if (timeout < 0 || timeout > 63) { 337 printk(KERN_ERR PFX "Invalid timeout index (must be 0-63).\n"); 338 res = -EINVAL; 339 goto out; 340 } 341 342 if (!request_region(SBC8360_ENABLE, 1, "SBC8360")) { 343 printk(KERN_ERR PFX "ENABLE method I/O %X is not available.\n", 344 SBC8360_ENABLE); 345 res = -EIO; 346 goto out; 347 } 348 if (!request_region(SBC8360_BASETIME, 1, "SBC8360")) { 349 printk(KERN_ERR PFX 350 "BASETIME method I/O %X is not available.\n", 351 SBC8360_BASETIME); 352 res = -EIO; 353 goto out_nobasetimereg; 354 } 355 356 res = register_reboot_notifier(&sbc8360_notifier); 357 if (res) { 358 printk(KERN_ERR PFX "Failed to register reboot notifier.\n"); 359 goto out_noreboot; 360 } 361 362 res = misc_register(&sbc8360_miscdev); 363 if (res) { 364 printk(KERN_ERR PFX "failed to register misc device\n"); 365 goto out_nomisc; 366 } 367 368 wd_margin = wd_times[timeout][0]; 369 wd_multiplier = wd_times[timeout][1]; 370 371 if (wd_multiplier == 1) 372 mseconds = (wd_margin + 1) * 500; 373 else if (wd_multiplier == 2) 374 mseconds = (wd_margin + 1) * 5000; 375 else if (wd_multiplier == 3) 376 mseconds = (wd_margin + 1) * 50000; 377 else if (wd_multiplier == 4) 378 mseconds = (wd_margin + 1) * 100000; 379 380 /* My kingdom for the ability to print "0.5 seconds" in the kernel! */ 381 printk(KERN_INFO PFX "Timeout set at %ld ms.\n", mseconds); 382 383 return 0; 384 385out_nomisc: 386 unregister_reboot_notifier(&sbc8360_notifier); 387out_noreboot: 388 release_region(SBC8360_BASETIME, 1); 389out_nobasetimereg: 390 release_region(SBC8360_ENABLE, 1); 391out: 392 return res; 393} 394 395static void __exit sbc8360_exit(void) 396{ 397 misc_deregister(&sbc8360_miscdev); 398 unregister_reboot_notifier(&sbc8360_notifier); 399 release_region(SBC8360_ENABLE, 1); 400 release_region(SBC8360_BASETIME, 1); 401} 402 403module_init(sbc8360_init); 404module_exit(sbc8360_exit); 405 406MODULE_AUTHOR("Ian E. Morgan <imorgan@webcon.ca>"); 407MODULE_DESCRIPTION("SBC8360 watchdog driver"); 408MODULE_LICENSE("GPL"); 409MODULE_VERSION("1.01"); 410MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 411 412/* end of sbc8360.c */ 413