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@redhat.com>, All Rights Reserved. 20 * http://www.redhat.com 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@redhat.com> 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 52 #include <asm/io.h> 53 #include <asm/uaccess.h> 54 #include <asm/system.h> 55 56 static unsigned long sbc8360_is_open; 57 static DEFINE_SPINLOCK(sbc8360_lock); 58 static char expect_close; 59 60 #define PFX "sbc8360: " 61 62 /* 63 * 64 * Watchdog Timer Configuration 65 * 66 * The function of the watchdog timer is to reset the system automatically 67 * and is defined at I/O port 0120H and 0121H. To enable the watchdog timer 68 * and allow the system to reset, write appropriate values from the table 69 * below to I/O port 0120H and 0121H. To disable the timer, write a zero 70 * value to I/O port 0121H for the system to stop the watchdog function. 71 * 72 * The following describes how the timer should be programmed (according to 73 * the vendor documentation) 74 * 75 * Enabling Watchdog: 76 * MOV AX,000AH (enable, phase I) 77 * MOV DX,0120H 78 * OUT DX,AX 79 * MOV AX,000BH (enable, phase II) 80 * MOV DX,0120H 81 * OUT DX,AX 82 * MOV AX,000nH (set multiplier n, from 1-4) 83 * MOV DX,0120H 84 * OUT DX,AX 85 * MOV AX,000mH (set base timer m, from 0-F) 86 * MOV DX,0121H 87 * OUT DX,AX 88 * 89 * Reset timer: 90 * MOV AX,000mH (same as set base timer, above) 91 * MOV DX,0121H 92 * OUT DX,AX 93 * 94 * Disabling Watchdog: 95 * MOV AX,0000H (a zero value) 96 * MOV DX,0120H 97 * OUT DX,AX 98 * 99 * Watchdog timeout configuration values: 100 * N 101 * M | 1 2 3 4 102 * --|---------------------------------- 103 * 0 | 0.5s 5s 50s 100s 104 * 1 | 1s 10s 100s 200s 105 * 2 | 1.5s 15s 150s 300s 106 * 3 | 2s 20s 200s 400s 107 * 4 | 2.5s 25s 250s 500s 108 * 5 | 3s 30s 300s 600s 109 * 6 | 3.5s 35s 350s 700s 110 * 7 | 4s 40s 400s 800s 111 * 8 | 4.5s 45s 450s 900s 112 * 9 | 5s 50s 500s 1000s 113 * A | 5.5s 55s 550s 1100s 114 * B | 6s 60s 600s 1200s 115 * C | 6.5s 65s 650s 1300s 116 * D | 7s 70s 700s 1400s 117 * E | 7.5s 75s 750s 1500s 118 * F | 8s 80s 800s 1600s 119 * 120 * Another way to say the same things is: 121 * For N=1, Timeout = (M+1) * 0.5s 122 * For N=2, Timeout = (M+1) * 5s 123 * For N=3, Timeout = (M+1) * 50s 124 * For N=4, Timeout = (M+1) * 100s 125 * 126 */ 127 128 static int wd_times[64][2] = { 129 {0, 1}, /* 0 = 0.5s */ 130 {1, 1}, /* 1 = 1s */ 131 {2, 1}, /* 2 = 1.5s */ 132 {3, 1}, /* 3 = 2s */ 133 {4, 1}, /* 4 = 2.5s */ 134 {5, 1}, /* 5 = 3s */ 135 {6, 1}, /* 6 = 3.5s */ 136 {7, 1}, /* 7 = 4s */ 137 {8, 1}, /* 8 = 4.5s */ 138 {9, 1}, /* 9 = 5s */ 139 {0xA, 1}, /* 10 = 5.5s */ 140 {0xB, 1}, /* 11 = 6s */ 141 {0xC, 1}, /* 12 = 6.5s */ 142 {0xD, 1}, /* 13 = 7s */ 143 {0xE, 1}, /* 14 = 7.5s */ 144 {0xF, 1}, /* 15 = 8s */ 145 {0, 2}, /* 16 = 5s */ 146 {1, 2}, /* 17 = 10s */ 147 {2, 2}, /* 18 = 15s */ 148 {3, 2}, /* 19 = 20s */ 149 {4, 2}, /* 20 = 25s */ 150 {5, 2}, /* 21 = 30s */ 151 {6, 2}, /* 22 = 35s */ 152 {7, 2}, /* 23 = 40s */ 153 {8, 2}, /* 24 = 45s */ 154 {9, 2}, /* 25 = 50s */ 155 {0xA, 2}, /* 26 = 55s */ 156 {0xB, 2}, /* 27 = 60s */ 157 {0xC, 2}, /* 28 = 65s */ 158 {0xD, 2}, /* 29 = 70s */ 159 {0xE, 2}, /* 30 = 75s */ 160 {0xF, 2}, /* 31 = 80s */ 161 {0, 3}, /* 32 = 50s */ 162 {1, 3}, /* 33 = 100s */ 163 {2, 3}, /* 34 = 150s */ 164 {3, 3}, /* 35 = 200s */ 165 {4, 3}, /* 36 = 250s */ 166 {5, 3}, /* 37 = 300s */ 167 {6, 3}, /* 38 = 350s */ 168 {7, 3}, /* 39 = 400s */ 169 {8, 3}, /* 40 = 450s */ 170 {9, 3}, /* 41 = 500s */ 171 {0xA, 3}, /* 42 = 550s */ 172 {0xB, 3}, /* 43 = 600s */ 173 {0xC, 3}, /* 44 = 650s */ 174 {0xD, 3}, /* 45 = 700s */ 175 {0xE, 3}, /* 46 = 750s */ 176 {0xF, 3}, /* 47 = 800s */ 177 {0, 4}, /* 48 = 100s */ 178 {1, 4}, /* 49 = 200s */ 179 {2, 4}, /* 50 = 300s */ 180 {3, 4}, /* 51 = 400s */ 181 {4, 4}, /* 52 = 500s */ 182 {5, 4}, /* 53 = 600s */ 183 {6, 4}, /* 54 = 700s */ 184 {7, 4}, /* 55 = 800s */ 185 {8, 4}, /* 56 = 900s */ 186 {9, 4}, /* 57 = 1000s */ 187 {0xA, 4}, /* 58 = 1100s */ 188 {0xB, 4}, /* 59 = 1200s */ 189 {0xC, 4}, /* 60 = 1300s */ 190 {0xD, 4}, /* 61 = 1400s */ 191 {0xE, 4}, /* 62 = 1500s */ 192 {0xF, 4} /* 63 = 1600s */ 193 }; 194 195 #define SBC8360_ENABLE 0x120 196 #define SBC8360_BASETIME 0x121 197 198 static int timeout = 27; 199 static int wd_margin = 0xB; 200 static int wd_multiplier = 2; 201 static int nowayout = WATCHDOG_NOWAYOUT; 202 203 module_param(timeout, int, 0); 204 MODULE_PARM_DESC(timeout, "Index into timeout table (0-63) (default=27 (60s))"); 205 module_param(nowayout, int, 0); 206 MODULE_PARM_DESC(nowayout, 207 "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 208 209 /* 210 * Kernel methods. 211 */ 212 213 /* Activate and pre-configure watchdog */ 214 static 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 */ 228 static void sbc8360_ping(void) 229 { 230 /* Write the base timer register */ 231 outb(wd_margin, SBC8360_BASETIME); 232 } 233 234 /* Userspace pings kernel driver, or requests clean close */ 235 static ssize_t sbc8360_write(struct file *file, const char __user * buf, 236 size_t count, loff_t * ppos) 237 { 238 if (count) { 239 if (!nowayout) { 240 size_t i; 241 242 /* In case it was set long ago */ 243 expect_close = 0; 244 245 for (i = 0; i != count; i++) { 246 char c; 247 if (get_user(c, buf + i)) 248 return -EFAULT; 249 if (c == 'V') 250 expect_close = 42; 251 } 252 } 253 sbc8360_ping(); 254 } 255 return count; 256 } 257 258 static int sbc8360_open(struct inode *inode, struct file *file) 259 { 260 spin_lock(&sbc8360_lock); 261 if (test_and_set_bit(0, &sbc8360_is_open)) { 262 spin_unlock(&sbc8360_lock); 263 return -EBUSY; 264 } 265 if (nowayout) 266 __module_get(THIS_MODULE); 267 268 /* Activate and ping once to start the countdown */ 269 spin_unlock(&sbc8360_lock); 270 sbc8360_activate(); 271 sbc8360_ping(); 272 return nonseekable_open(inode, file); 273 } 274 275 static int sbc8360_close(struct inode *inode, struct file *file) 276 { 277 spin_lock(&sbc8360_lock); 278 if (expect_close == 42) 279 outb(0, SBC8360_ENABLE); 280 else 281 printk(KERN_CRIT PFX 282 "SBC8360 device closed unexpectedly. SBC8360 will not stop!\n"); 283 284 clear_bit(0, &sbc8360_is_open); 285 expect_close = 0; 286 spin_unlock(&sbc8360_lock); 287 return 0; 288 } 289 290 /* 291 * Notifier for system down 292 */ 293 294 static int sbc8360_notify_sys(struct notifier_block *this, unsigned long code, 295 void *unused) 296 { 297 if (code == SYS_DOWN || code == SYS_HALT) { 298 /* Disable the SBC8360 Watchdog */ 299 outb(0, SBC8360_ENABLE); 300 } 301 return NOTIFY_DONE; 302 } 303 304 /* 305 * Kernel Interfaces 306 */ 307 308 static 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 }; 315 316 static 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 */ 326 327 static struct notifier_block sbc8360_notifier = { 328 .notifier_call = sbc8360_notify_sys, 329 }; 330 331 static 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; 384 385 out_nomisc: 386 unregister_reboot_notifier(&sbc8360_notifier); 387 out_noreboot: 388 release_region(SBC8360_BASETIME, 1); 389 out_nobasetimereg: 390 release_region(SBC8360_ENABLE, 1); 391 out: 392 return res; 393 } 394 395 static 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 } 402 403 module_init(sbc8360_init); 404 module_exit(sbc8360_exit); 405 406 MODULE_AUTHOR("Ian E. Morgan <imorgan@webcon.ca>"); 407 MODULE_DESCRIPTION("SBC8360 watchdog driver"); 408 MODULE_LICENSE("GPL"); 409 MODULE_VERSION("1.01"); 410 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 411 412 /* end of sbc8360.c */ 413