1/* 2 * SMsC 37B787 Watchdog Timer driver for Linux 2.6.x.x 3 * 4 * Based on acquirewdt.c by Alan Cox <alan@lxorguk.ukuu.org.uk> 5 * and some other existing drivers 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 * 12 * The authors do NOT admit liability nor provide warranty for 13 * any of this software. This material is provided "AS-IS" in 14 * the hope that it may be useful for others. 15 * 16 * (C) Copyright 2003-2006 Sven Anders <anders@anduras.de> 17 * 18 * History: 19 * 2003 - Created version 1.0 for Linux 2.4.x. 20 * 2006 - Ported to Linux 2.6, added nowayout and MAGICCLOSE 21 * features. Released version 1.1 22 * 23 * Theory of operation: 24 * 25 * A Watchdog Timer (WDT) is a hardware circuit that can 26 * reset the computer system in case of a software fault. 27 * You probably knew that already. 28 * 29 * Usually a userspace daemon will notify the kernel WDT driver 30 * via the /dev/watchdog special device file that userspace is 31 * still alive, at regular intervals. When such a notification 32 * occurs, the driver will usually tell the hardware watchdog 33 * that everything is in order, and that the watchdog should wait 34 * for yet another little while to reset the system. 35 * If userspace fails (RAM error, kernel bug, whatever), the 36 * notifications cease to occur, and the hardware watchdog will 37 * reset the system (causing a reboot) after the timeout occurs. 38 * 39 * Create device with: 40 * mknod /dev/watchdog c 10 130 41 * 42 * For an example userspace keep-alive daemon, see: 43 * Documentation/watchdog/watchdog.txt 44 */ 45 46#include <linux/module.h> 47#include <linux/moduleparam.h> 48#include <linux/types.h> 49#include <linux/miscdevice.h> 50#include <linux/watchdog.h> 51#include <linux/delay.h> 52#include <linux/fs.h> 53#include <linux/ioport.h> 54#include <linux/notifier.h> 55#include <linux/reboot.h> 56#include <linux/init.h> 57#include <linux/spinlock.h> 58#include <linux/io.h> 59#include <linux/uaccess.h> 60 61#include <asm/system.h> 62 63/* enable support for minutes as units? */ 64/* (does not always work correctly, so disabled by default!) */ 65#define SMSC_SUPPORT_MINUTES 66#undef SMSC_SUPPORT_MINUTES 67 68#define MAX_TIMEOUT 255 69 70#define UNIT_SECOND 0 71#define UNIT_MINUTE 1 72 73#define MODNAME "smsc37b787_wdt: " 74#define VERSION "1.1" 75 76#define IOPORT 0x3F0 77#define IOPORT_SIZE 2 78#define IODEV_NO 8 79 80static int unit = UNIT_SECOND; /* timer's unit */ 81static int timeout = 60; /* timeout value: default is 60 "units" */ 82static unsigned long timer_enabled; /* is the timer enabled? */ 83 84static char expect_close; /* is the close expected? */ 85 86static DEFINE_SPINLOCK(io_lock);/* to guard the watchdog from io races */ 87 88static int nowayout = WATCHDOG_NOWAYOUT; 89 90/* -- Low level function ----------------------------------------*/ 91 92/* unlock the IO chip */ 93 94static inline void open_io_config(void) 95{ 96 outb(0x55, IOPORT); 97 mdelay(1); 98 outb(0x55, IOPORT); 99} 100 101/* lock the IO chip */ 102static inline void close_io_config(void) 103{ 104 outb(0xAA, IOPORT); 105} 106 107/* select the IO device */ 108static inline void select_io_device(unsigned char devno) 109{ 110 outb(0x07, IOPORT); 111 outb(devno, IOPORT+1); 112} 113 114/* write to the control register */ 115static inline void write_io_cr(unsigned char reg, unsigned char data) 116{ 117 outb(reg, IOPORT); 118 outb(data, IOPORT+1); 119} 120 121/* read from the control register */ 122static inline char read_io_cr(unsigned char reg) 123{ 124 outb(reg, IOPORT); 125 return inb(IOPORT+1); 126} 127 128/* -- Medium level functions ------------------------------------*/ 129 130static inline void gpio_bit12(unsigned char reg) 131{ 132 /* -- General Purpose I/O Bit 1.2 -- 133 * Bit 0, In/Out: 0 = Output, 1 = Input 134 * Bit 1, Polarity: 0 = No Invert, 1 = Invert 135 * Bit 2, Group Enable Intr.: 0 = Disable, 1 = Enable 136 * Bit 3/4, Function select: 00 = GPI/O, 01 = WDT, 10 = P17, 137 * 11 = Either Edge Triggered Intr. 2 138 * Bit 5/6 (Reserved) 139 * Bit 7, Output Type: 0 = Push Pull Bit, 1 = Open Drain 140 */ 141 write_io_cr(0xE2, reg); 142} 143 144static inline void gpio_bit13(unsigned char reg) 145{ 146 /* -- General Purpose I/O Bit 1.3 -- 147 * Bit 0, In/Out: 0 = Output, 1 = Input 148 * Bit 1, Polarity: 0 = No Invert, 1 = Invert 149 * Bit 2, Group Enable Intr.: 0 = Disable, 1 = Enable 150 * Bit 3, Function select: 0 = GPI/O, 1 = LED 151 * Bit 4-6 (Reserved) 152 * Bit 7, Output Type: 0 = Push Pull Bit, 1 = Open Drain 153 */ 154 write_io_cr(0xE3, reg); 155} 156 157static inline void wdt_timer_units(unsigned char new_units) 158{ 159 /* -- Watchdog timer units -- 160 * Bit 0-6 (Reserved) 161 * Bit 7, WDT Time-out Value Units Select 162 * (0 = Minutes, 1 = Seconds) 163 */ 164 write_io_cr(0xF1, new_units); 165} 166 167static inline void wdt_timeout_value(unsigned char new_timeout) 168{ 169 /* -- Watchdog Timer Time-out Value -- 170 * Bit 0-7 Binary coded units (0=Disabled, 1..255) 171 */ 172 write_io_cr(0xF2, new_timeout); 173} 174 175static inline void wdt_timer_conf(unsigned char conf) 176{ 177 /* -- Watchdog timer configuration -- 178 * Bit 0 Joystick enable: 0* = No Reset, 1 = Reset WDT upon 179 * Gameport I/O 180 * Bit 1 Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr. 181 * Bit 2 Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr 182 * Bit 3 Reset the timer 183 * (Wrong in SMsC documentation? Given as: PowerLED Timout 184 * Enabled) 185 * Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled, 186 * 0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15) 187 */ 188 write_io_cr(0xF3, conf); 189} 190 191static inline void wdt_timer_ctrl(unsigned char reg) 192{ 193 /* -- Watchdog timer control -- 194 * Bit 0 Status Bit: 0 = Timer counting, 1 = Timeout occured 195 * Bit 1 Power LED Toggle: 0 = Disable Toggle, 1 = Toggle at 1 Hz 196 * Bit 2 Force Timeout: 1 = Forces WD timeout event (self-cleaning) 197 * Bit 3 P20 Force Timeout enabled: 198 * 0 = P20 activity does not generate the WD timeout event 199 * 1 = P20 Allows rising edge of P20, from the keyboard 200 * controller, to force the WD timeout event. 201 * Bit 4 (Reserved) 202 * -- Soft power management -- 203 * Bit 5 Stop Counter: 1 = Stop software power down counter 204 * set via register 0xB8, (self-cleaning) 205 * (Upon read: 0 = Counter running, 1 = Counter stopped) 206 * Bit 6 Restart Counter: 1 = Restart software power down counter 207 * set via register 0xB8, (self-cleaning) 208 * Bit 7 SPOFF: 1 = Force software power down (self-cleaning) 209 */ 210 write_io_cr(0xF4, reg); 211} 212 213/* -- Higher level functions ------------------------------------*/ 214 215/* initialize watchdog */ 216 217static void wb_smsc_wdt_initialize(void) 218{ 219 unsigned char old; 220 221 spin_lock(&io_lock); 222 open_io_config(); 223 select_io_device(IODEV_NO); 224 225 /* enable the watchdog */ 226 gpio_bit13(0x08); /* Select pin 80 = LED not GPIO */ 227 gpio_bit12(0x0A); /* Set pin 79 = WDT not 228 GPIO/Output/Polarity=Invert */ 229 /* disable the timeout */ 230 wdt_timeout_value(0); 231 232 /* reset control register */ 233 wdt_timer_ctrl(0x00); 234 235 /* reset configuration register */ 236 wdt_timer_conf(0x00); 237 238 /* read old (timer units) register */ 239 old = read_io_cr(0xF1) & 0x7F; 240 if (unit == UNIT_SECOND) 241 old |= 0x80; /* set to seconds */ 242 243 /* set the watchdog timer units */ 244 wdt_timer_units(old); 245 246 close_io_config(); 247 spin_unlock(&io_lock); 248} 249 250/* shutdown the watchdog */ 251 252static void wb_smsc_wdt_shutdown(void) 253{ 254 spin_lock(&io_lock); 255 open_io_config(); 256 select_io_device(IODEV_NO); 257 258 /* disable the watchdog */ 259 gpio_bit13(0x09); 260 gpio_bit12(0x09); 261 262 /* reset watchdog config register */ 263 wdt_timer_conf(0x00); 264 265 /* reset watchdog control register */ 266 wdt_timer_ctrl(0x00); 267 268 /* disable timeout */ 269 wdt_timeout_value(0x00); 270 271 close_io_config(); 272 spin_unlock(&io_lock); 273} 274 275/* set timeout => enable watchdog */ 276 277static void wb_smsc_wdt_set_timeout(unsigned char new_timeout) 278{ 279 spin_lock(&io_lock); 280 open_io_config(); 281 select_io_device(IODEV_NO); 282 283 /* set Power LED to blink, if we enable the timeout */ 284 wdt_timer_ctrl((new_timeout == 0) ? 0x00 : 0x02); 285 286 /* set timeout value */ 287 wdt_timeout_value(new_timeout); 288 289 close_io_config(); 290 spin_unlock(&io_lock); 291} 292 293/* get timeout */ 294 295static unsigned char wb_smsc_wdt_get_timeout(void) 296{ 297 unsigned char set_timeout; 298 299 spin_lock(&io_lock); 300 open_io_config(); 301 select_io_device(IODEV_NO); 302 set_timeout = read_io_cr(0xF2); 303 close_io_config(); 304 spin_unlock(&io_lock); 305 306 return set_timeout; 307} 308 309/* disable watchdog */ 310 311static void wb_smsc_wdt_disable(void) 312{ 313 /* set the timeout to 0 to disable the watchdog */ 314 wb_smsc_wdt_set_timeout(0); 315} 316 317/* enable watchdog by setting the current timeout */ 318 319static void wb_smsc_wdt_enable(void) 320{ 321 /* set the current timeout... */ 322 wb_smsc_wdt_set_timeout(timeout); 323} 324 325/* reset the timer */ 326 327static void wb_smsc_wdt_reset_timer(void) 328{ 329 spin_lock(&io_lock); 330 open_io_config(); 331 select_io_device(IODEV_NO); 332 333 /* reset the timer */ 334 wdt_timeout_value(timeout); 335 wdt_timer_conf(0x08); 336 337 close_io_config(); 338 spin_unlock(&io_lock); 339} 340 341/* return, if the watchdog is enabled (timeout is set...) */ 342 343static int wb_smsc_wdt_status(void) 344{ 345 return (wb_smsc_wdt_get_timeout() == 0) ? 0 : WDIOF_KEEPALIVEPING; 346} 347 348 349/* -- File operations -------------------------------------------*/ 350 351/* open => enable watchdog and set initial timeout */ 352 353static int wb_smsc_wdt_open(struct inode *inode, struct file *file) 354{ 355 /* /dev/watchdog can only be opened once */ 356 357 if (test_and_set_bit(0, &timer_enabled)) 358 return -EBUSY; 359 360 if (nowayout) 361 __module_get(THIS_MODULE); 362 363 /* Reload and activate timer */ 364 wb_smsc_wdt_enable(); 365 366 printk(KERN_INFO MODNAME 367 "Watchdog enabled. Timeout set to %d %s.\n", 368 timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)"); 369 370 return nonseekable_open(inode, file); 371} 372 373/* close => shut off the timer */ 374 375static int wb_smsc_wdt_release(struct inode *inode, struct file *file) 376{ 377 /* Shut off the timer. */ 378 379 if (expect_close == 42) { 380 wb_smsc_wdt_disable(); 381 printk(KERN_INFO MODNAME 382 "Watchdog disabled, sleeping again...\n"); 383 } else { 384 printk(KERN_CRIT MODNAME 385 "Unexpected close, not stopping watchdog!\n"); 386 wb_smsc_wdt_reset_timer(); 387 } 388 389 clear_bit(0, &timer_enabled); 390 expect_close = 0; 391 return 0; 392} 393 394/* write => update the timer to keep the machine alive */ 395 396static ssize_t wb_smsc_wdt_write(struct file *file, const char __user *data, 397 size_t len, loff_t *ppos) 398{ 399 /* See if we got the magic character 'V' and reload the timer */ 400 if (len) { 401 if (!nowayout) { 402 size_t i; 403 404 /* reset expect flag */ 405 expect_close = 0; 406 407 /* scan to see whether or not we got the 408 magic character */ 409 for (i = 0; i != len; i++) { 410 char c; 411 if (get_user(c, data + i)) 412 return -EFAULT; 413 if (c == 'V') 414 expect_close = 42; 415 } 416 } 417 418 /* someone wrote to us, we should reload the timer */ 419 wb_smsc_wdt_reset_timer(); 420 } 421 return len; 422} 423 424/* ioctl => control interface */ 425 426static long wb_smsc_wdt_ioctl(struct file *file, 427 unsigned int cmd, unsigned long arg) 428{ 429 int new_timeout; 430 431 union { 432 struct watchdog_info __user *ident; 433 int __user *i; 434 } uarg; 435 436 static const struct watchdog_info ident = { 437 .options = WDIOF_KEEPALIVEPING | 438 WDIOF_SETTIMEOUT | 439 WDIOF_MAGICCLOSE, 440 .firmware_version = 0, 441 .identity = "SMsC 37B787 Watchdog", 442 }; 443 444 uarg.i = (int __user *)arg; 445 446 switch (cmd) { 447 case WDIOC_GETSUPPORT: 448 return copy_to_user(uarg.ident, &ident, sizeof(ident)) 449 ? -EFAULT : 0; 450 case WDIOC_GETSTATUS: 451 return put_user(wb_smsc_wdt_status(), uarg.i); 452 case WDIOC_GETBOOTSTATUS: 453 return put_user(0, uarg.i); 454 case WDIOC_SETOPTIONS: 455 { 456 int options, retval = -EINVAL; 457 458 if (get_user(options, uarg.i)) 459 return -EFAULT; 460 461 if (options & WDIOS_DISABLECARD) { 462 wb_smsc_wdt_disable(); 463 retval = 0; 464 } 465 if (options & WDIOS_ENABLECARD) { 466 wb_smsc_wdt_enable(); 467 retval = 0; 468 } 469 return retval; 470 } 471 case WDIOC_KEEPALIVE: 472 wb_smsc_wdt_reset_timer(); 473 return 0; 474 case WDIOC_SETTIMEOUT: 475 if (get_user(new_timeout, uarg.i)) 476 return -EFAULT; 477 /* the API states this is given in secs */ 478 if (unit == UNIT_MINUTE) 479 new_timeout /= 60; 480 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT) 481 return -EINVAL; 482 timeout = new_timeout; 483 wb_smsc_wdt_set_timeout(timeout); 484 /* fall through and return the new timeout... */ 485 case WDIOC_GETTIMEOUT: 486 new_timeout = timeout; 487 if (unit == UNIT_MINUTE) 488 new_timeout *= 60; 489 return put_user(new_timeout, uarg.i); 490 default: 491 return -ENOTTY; 492 } 493} 494 495/* -- Notifier funtions -----------------------------------------*/ 496 497static int wb_smsc_wdt_notify_sys(struct notifier_block *this, 498 unsigned long code, void *unused) 499{ 500 if (code == SYS_DOWN || code == SYS_HALT) { 501 /* set timeout to 0, to avoid possible race-condition */ 502 timeout = 0; 503 wb_smsc_wdt_disable(); 504 } 505 return NOTIFY_DONE; 506} 507 508/* -- Module's structures ---------------------------------------*/ 509 510static const struct file_operations wb_smsc_wdt_fops = { 511 .owner = THIS_MODULE, 512 .llseek = no_llseek, 513 .write = wb_smsc_wdt_write, 514 .unlocked_ioctl = wb_smsc_wdt_ioctl, 515 .open = wb_smsc_wdt_open, 516 .release = wb_smsc_wdt_release, 517}; 518 519static struct notifier_block wb_smsc_wdt_notifier = { 520 .notifier_call = wb_smsc_wdt_notify_sys, 521}; 522 523static struct miscdevice wb_smsc_wdt_miscdev = { 524 .minor = WATCHDOG_MINOR, 525 .name = "watchdog", 526 .fops = &wb_smsc_wdt_fops, 527}; 528 529/* -- Module init functions -------------------------------------*/ 530 531/* module's "constructor" */ 532 533static int __init wb_smsc_wdt_init(void) 534{ 535 int ret; 536 537 printk(KERN_INFO "SMsC 37B787 watchdog component driver " 538 VERSION " initialising...\n"); 539 540 if (!request_region(IOPORT, IOPORT_SIZE, "SMsC 37B787 watchdog")) { 541 printk(KERN_ERR MODNAME "Unable to register IO port %#x\n", 542 IOPORT); 543 ret = -EBUSY; 544 goto out_pnp; 545 } 546 547 /* set new maximum, if it's too big */ 548 if (timeout > MAX_TIMEOUT) 549 timeout = MAX_TIMEOUT; 550 551 /* init the watchdog timer */ 552 wb_smsc_wdt_initialize(); 553 554 ret = register_reboot_notifier(&wb_smsc_wdt_notifier); 555 if (ret) { 556 printk(KERN_ERR MODNAME 557 "Unable to register reboot notifier err = %d\n", ret); 558 goto out_io; 559 } 560 561 ret = misc_register(&wb_smsc_wdt_miscdev); 562 if (ret) { 563 printk(KERN_ERR MODNAME 564 "Unable to register miscdev on minor %d\n", 565 WATCHDOG_MINOR); 566 goto out_rbt; 567 } 568 569 /* output info */ 570 printk(KERN_INFO MODNAME "Timeout set to %d %s.\n", 571 timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)"); 572 printk(KERN_INFO MODNAME 573 "Watchdog initialized and sleeping (nowayout=%d)...\n", 574 nowayout); 575out_clean: 576 return ret; 577 578out_rbt: 579 unregister_reboot_notifier(&wb_smsc_wdt_notifier); 580 581out_io: 582 release_region(IOPORT, IOPORT_SIZE); 583 584out_pnp: 585 goto out_clean; 586} 587 588/* module's "destructor" */ 589 590static void __exit wb_smsc_wdt_exit(void) 591{ 592 /* Stop the timer before we leave */ 593 if (!nowayout) { 594 wb_smsc_wdt_shutdown(); 595 printk(KERN_INFO MODNAME "Watchdog disabled.\n"); 596 } 597 598 misc_deregister(&wb_smsc_wdt_miscdev); 599 unregister_reboot_notifier(&wb_smsc_wdt_notifier); 600 release_region(IOPORT, IOPORT_SIZE); 601 602 printk(KERN_INFO "SMsC 37B787 watchdog component driver removed.\n"); 603} 604 605module_init(wb_smsc_wdt_init); 606module_exit(wb_smsc_wdt_exit); 607 608MODULE_AUTHOR("Sven Anders <anders@anduras.de>"); 609MODULE_DESCRIPTION("Driver for SMsC 37B787 watchdog component (Version " 610 VERSION ")"); 611MODULE_LICENSE("GPL"); 612 613MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 614 615#ifdef SMSC_SUPPORT_MINUTES 616module_param(unit, int, 0); 617MODULE_PARM_DESC(unit, 618 "set unit to use, 0=seconds or 1=minutes, default is 0"); 619#endif 620 621module_param(timeout, int, 0); 622MODULE_PARM_DESC(timeout, "range is 1-255 units, default is 60"); 623 624module_param(nowayout, int, 0); 625MODULE_PARM_DESC(nowayout, 626 "Watchdog cannot be stopped once started (default=" 627 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 628