1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Industrial Computer Source WDT501 driver 4 * 5 * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>, 6 * All Rights Reserved. 7 * 8 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide 9 * warranty for any of this software. This material is provided 10 * "AS-IS" and at no charge. 11 * 12 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> 13 * 14 * Release 0.10. 15 * 16 * Fixes 17 * Dave Gregorich : Modularisation and minor bugs 18 * Alan Cox : Added the watchdog ioctl() stuff 19 * Alan Cox : Fixed the reboot problem (as noted by 20 * Matt Crocker). 21 * Alan Cox : Added wdt= boot option 22 * Alan Cox : Cleaned up copy/user stuff 23 * Tim Hockin : Added insmod parameters, comment 24 * cleanup, parameterized timeout 25 * Tigran Aivazian : Restructured wdt_init() to handle 26 * failures 27 * Joel Becker : Added WDIOC_GET/SETTIMEOUT 28 * Matt Domsch : Added nowayout module option 29 */ 30 31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 32 33 #include <linux/interrupt.h> 34 #include <linux/module.h> 35 #include <linux/moduleparam.h> 36 #include <linux/types.h> 37 #include <linux/miscdevice.h> 38 #include <linux/watchdog.h> 39 #include <linux/fs.h> 40 #include <linux/ioport.h> 41 #include <linux/notifier.h> 42 #include <linux/reboot.h> 43 #include <linux/init.h> 44 #include <linux/io.h> 45 #include <linux/uaccess.h> 46 47 #include "wd501p.h" 48 49 static unsigned long wdt_is_open; 50 static char expect_close; 51 52 /* 53 * Module parameters 54 */ 55 56 #define WD_TIMO 60 /* Default heartbeat = 60 seconds */ 57 58 static int heartbeat = WD_TIMO; 59 static int wd_heartbeat; 60 module_param(heartbeat, int, 0); 61 MODULE_PARM_DESC(heartbeat, 62 "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default=" 63 __MODULE_STRING(WD_TIMO) ")"); 64 65 static bool nowayout = WATCHDOG_NOWAYOUT; 66 module_param(nowayout, bool, 0); 67 MODULE_PARM_DESC(nowayout, 68 "Watchdog cannot be stopped once started (default=" 69 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 70 71 /* You must set these - there is no sane way to probe for this board. */ 72 static int io = 0x240; 73 static int irq = 11; 74 75 static DEFINE_SPINLOCK(wdt_lock); 76 77 module_param_hw(io, int, ioport, 0); 78 MODULE_PARM_DESC(io, "WDT io port (default=0x240)"); 79 module_param_hw(irq, int, irq, 0); 80 MODULE_PARM_DESC(irq, "WDT irq (default=11)"); 81 82 /* Support for the Fan Tachometer on the WDT501-P */ 83 static int tachometer; 84 module_param(tachometer, int, 0); 85 MODULE_PARM_DESC(tachometer, 86 "WDT501-P Fan Tachometer support (0=disable, default=0)"); 87 88 static int type = 500; 89 module_param(type, int, 0); 90 MODULE_PARM_DESC(type, 91 "WDT501-P Card type (500 or 501, default=500)"); 92 93 /* 94 * Programming support 95 */ 96 97 static void wdt_ctr_mode(int ctr, int mode) 98 { 99 ctr <<= 6; 100 ctr |= 0x30; 101 ctr |= (mode << 1); 102 outb_p(ctr, WDT_CR); 103 } 104 105 static void wdt_ctr_load(int ctr, int val) 106 { 107 outb_p(val&0xFF, WDT_COUNT0+ctr); 108 outb_p(val>>8, WDT_COUNT0+ctr); 109 } 110 111 /** 112 * wdt_start: 113 * 114 * Start the watchdog driver. 115 */ 116 117 static int wdt_start(void) 118 { 119 unsigned long flags; 120 spin_lock_irqsave(&wdt_lock, flags); 121 inb_p(WDT_DC); /* Disable watchdog */ 122 wdt_ctr_mode(0, 3); /* Program CTR0 for Mode 3: 123 Square Wave Generator */ 124 wdt_ctr_mode(1, 2); /* Program CTR1 for Mode 2: 125 Rate Generator */ 126 wdt_ctr_mode(2, 0); /* Program CTR2 for Mode 0: 127 Pulse on Terminal Count */ 128 wdt_ctr_load(0, 8948); /* Count at 100Hz */ 129 wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */ 130 wdt_ctr_load(2, 65535); /* Length of reset pulse */ 131 outb_p(0, WDT_DC); /* Enable watchdog */ 132 spin_unlock_irqrestore(&wdt_lock, flags); 133 return 0; 134 } 135 136 /** 137 * wdt_stop: 138 * 139 * Stop the watchdog driver. 140 */ 141 142 static int wdt_stop(void) 143 { 144 unsigned long flags; 145 spin_lock_irqsave(&wdt_lock, flags); 146 /* Turn the card off */ 147 inb_p(WDT_DC); /* Disable watchdog */ 148 wdt_ctr_load(2, 0); /* 0 length reset pulses now */ 149 spin_unlock_irqrestore(&wdt_lock, flags); 150 return 0; 151 } 152 153 /** 154 * wdt_ping: 155 * 156 * Reload counter one with the watchdog heartbeat. We don't bother 157 * reloading the cascade counter. 158 */ 159 160 static void wdt_ping(void) 161 { 162 unsigned long flags; 163 spin_lock_irqsave(&wdt_lock, flags); 164 /* Write a watchdog value */ 165 inb_p(WDT_DC); /* Disable watchdog */ 166 wdt_ctr_mode(1, 2); /* Re-Program CTR1 for Mode 2: 167 Rate Generator */ 168 wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */ 169 outb_p(0, WDT_DC); /* Enable watchdog */ 170 spin_unlock_irqrestore(&wdt_lock, flags); 171 } 172 173 /** 174 * wdt_set_heartbeat: 175 * @t: the new heartbeat value that needs to be set. 176 * 177 * Set a new heartbeat value for the watchdog device. If the heartbeat 178 * value is incorrect we keep the old value and return -EINVAL. If 179 * successful we return 0. 180 */ 181 182 static int wdt_set_heartbeat(int t) 183 { 184 if (t < 1 || t > 65535) 185 return -EINVAL; 186 187 heartbeat = t; 188 wd_heartbeat = t * 100; 189 return 0; 190 } 191 192 /** 193 * wdt_get_status: 194 * 195 * Extract the status information from a WDT watchdog device. There are 196 * several board variants so we have to know which bits are valid. Some 197 * bits default to one and some to zero in order to be maximally painful. 198 * 199 * we then map the bits onto the status ioctl flags. 200 */ 201 202 static int wdt_get_status(void) 203 { 204 unsigned char new_status; 205 int status = 0; 206 unsigned long flags; 207 208 spin_lock_irqsave(&wdt_lock, flags); 209 new_status = inb_p(WDT_SR); 210 spin_unlock_irqrestore(&wdt_lock, flags); 211 212 if (new_status & WDC_SR_ISOI0) 213 status |= WDIOF_EXTERN1; 214 if (new_status & WDC_SR_ISII1) 215 status |= WDIOF_EXTERN2; 216 if (type == 501) { 217 if (!(new_status & WDC_SR_TGOOD)) 218 status |= WDIOF_OVERHEAT; 219 if (!(new_status & WDC_SR_PSUOVER)) 220 status |= WDIOF_POWEROVER; 221 if (!(new_status & WDC_SR_PSUUNDR)) 222 status |= WDIOF_POWERUNDER; 223 if (tachometer) { 224 if (!(new_status & WDC_SR_FANGOOD)) 225 status |= WDIOF_FANFAULT; 226 } 227 } 228 return status; 229 } 230 231 /** 232 * wdt_get_temperature: 233 * 234 * Reports the temperature in degrees Fahrenheit. The API is in 235 * farenheit. It was designed by an imperial measurement luddite. 236 */ 237 238 static int wdt_get_temperature(void) 239 { 240 unsigned short c; 241 unsigned long flags; 242 243 spin_lock_irqsave(&wdt_lock, flags); 244 c = inb_p(WDT_RT); 245 spin_unlock_irqrestore(&wdt_lock, flags); 246 return (c * 11 / 15) + 7; 247 } 248 249 static void wdt_decode_501(int status) 250 { 251 if (!(status & WDC_SR_TGOOD)) 252 pr_crit("Overheat alarm (%d)\n", inb_p(WDT_RT)); 253 if (!(status & WDC_SR_PSUOVER)) 254 pr_crit("PSU over voltage\n"); 255 if (!(status & WDC_SR_PSUUNDR)) 256 pr_crit("PSU under voltage\n"); 257 } 258 259 /** 260 * wdt_interrupt: 261 * @irq: Interrupt number 262 * @dev_id: Unused as we don't allow multiple devices. 263 * 264 * Handle an interrupt from the board. These are raised when the status 265 * map changes in what the board considers an interesting way. That means 266 * a failure condition occurring. 267 */ 268 269 static irqreturn_t wdt_interrupt(int irq, void *dev_id) 270 { 271 /* 272 * Read the status register see what is up and 273 * then printk it. 274 */ 275 unsigned char status; 276 277 spin_lock(&wdt_lock); 278 status = inb_p(WDT_SR); 279 280 pr_crit("WDT status %d\n", status); 281 282 if (type == 501) { 283 wdt_decode_501(status); 284 if (tachometer) { 285 if (!(status & WDC_SR_FANGOOD)) 286 pr_crit("Possible fan fault\n"); 287 } 288 } 289 if (!(status & WDC_SR_WCCR)) { 290 #ifdef SOFTWARE_REBOOT 291 #ifdef ONLY_TESTING 292 pr_crit("Would Reboot\n"); 293 #else 294 pr_crit("Initiating system reboot\n"); 295 emergency_restart(); 296 #endif 297 #else 298 pr_crit("Reset in 5ms\n"); 299 #endif 300 } 301 spin_unlock(&wdt_lock); 302 return IRQ_HANDLED; 303 } 304 305 306 /** 307 * wdt_write: 308 * @file: file handle to the watchdog 309 * @buf: buffer to write (unused as data does not matter here 310 * @count: count of bytes 311 * @ppos: pointer to the position to write. No seeks allowed 312 * 313 * A write to a watchdog device is defined as a keepalive signal. Any 314 * write of data will do, as we we don't define content meaning. 315 */ 316 317 static ssize_t wdt_write(struct file *file, const char __user *buf, 318 size_t count, loff_t *ppos) 319 { 320 if (count) { 321 if (!nowayout) { 322 size_t i; 323 324 /* In case it was set long ago */ 325 expect_close = 0; 326 327 for (i = 0; i != count; i++) { 328 char c; 329 if (get_user(c, buf + i)) 330 return -EFAULT; 331 if (c == 'V') 332 expect_close = 42; 333 } 334 } 335 wdt_ping(); 336 } 337 return count; 338 } 339 340 /** 341 * wdt_ioctl: 342 * @file: file handle to the device 343 * @cmd: watchdog command 344 * @arg: argument pointer 345 * 346 * The watchdog API defines a common set of functions for all watchdogs 347 * according to their available features. We only actually usefully support 348 * querying capabilities and current status. 349 */ 350 351 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 352 { 353 void __user *argp = (void __user *)arg; 354 int __user *p = argp; 355 int new_heartbeat; 356 int status; 357 358 struct watchdog_info ident = { 359 .options = WDIOF_SETTIMEOUT| 360 WDIOF_MAGICCLOSE| 361 WDIOF_KEEPALIVEPING, 362 .firmware_version = 1, 363 .identity = "WDT500/501", 364 }; 365 366 /* Add options according to the card we have */ 367 ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2); 368 if (type == 501) { 369 ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER| 370 WDIOF_POWEROVER); 371 if (tachometer) 372 ident.options |= WDIOF_FANFAULT; 373 } 374 375 switch (cmd) { 376 case WDIOC_GETSUPPORT: 377 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; 378 case WDIOC_GETSTATUS: 379 status = wdt_get_status(); 380 return put_user(status, p); 381 case WDIOC_GETBOOTSTATUS: 382 return put_user(0, p); 383 case WDIOC_KEEPALIVE: 384 wdt_ping(); 385 return 0; 386 case WDIOC_SETTIMEOUT: 387 if (get_user(new_heartbeat, p)) 388 return -EFAULT; 389 if (wdt_set_heartbeat(new_heartbeat)) 390 return -EINVAL; 391 wdt_ping(); 392 fallthrough; 393 case WDIOC_GETTIMEOUT: 394 return put_user(heartbeat, p); 395 default: 396 return -ENOTTY; 397 } 398 } 399 400 /** 401 * wdt_open: 402 * @inode: inode of device 403 * @file: file handle to device 404 * 405 * The watchdog device has been opened. The watchdog device is single 406 * open and on opening we load the counters. Counter zero is a 100Hz 407 * cascade, into counter 1 which downcounts to reboot. When the counter 408 * triggers counter 2 downcounts the length of the reset pulse which 409 * set set to be as long as possible. 410 */ 411 412 static int wdt_open(struct inode *inode, struct file *file) 413 { 414 if (test_and_set_bit(0, &wdt_is_open)) 415 return -EBUSY; 416 /* 417 * Activate 418 */ 419 wdt_start(); 420 return stream_open(inode, file); 421 } 422 423 /** 424 * wdt_release: 425 * @inode: inode to board 426 * @file: file handle to board 427 * 428 * The watchdog has a configurable API. There is a religious dispute 429 * between people who want their watchdog to be able to shut down and 430 * those who want to be sure if the watchdog manager dies the machine 431 * reboots. In the former case we disable the counters, in the latter 432 * case you have to open it again very soon. 433 */ 434 435 static int wdt_release(struct inode *inode, struct file *file) 436 { 437 if (expect_close == 42) { 438 wdt_stop(); 439 clear_bit(0, &wdt_is_open); 440 } else { 441 pr_crit("WDT device closed unexpectedly. WDT will not stop!\n"); 442 wdt_ping(); 443 } 444 expect_close = 0; 445 return 0; 446 } 447 448 /** 449 * wdt_temp_read: 450 * @file: file handle to the watchdog board 451 * @buf: buffer to write 1 byte into 452 * @count: length of buffer 453 * @ptr: offset (no seek allowed) 454 * 455 * Temp_read reports the temperature in degrees Fahrenheit. The API is in 456 * farenheit. It was designed by an imperial measurement luddite. 457 */ 458 459 static ssize_t wdt_temp_read(struct file *file, char __user *buf, 460 size_t count, loff_t *ptr) 461 { 462 int temperature = wdt_get_temperature(); 463 464 if (copy_to_user(buf, &temperature, 1)) 465 return -EFAULT; 466 467 return 1; 468 } 469 470 /** 471 * wdt_temp_open: 472 * @inode: inode of device 473 * @file: file handle to device 474 * 475 * The temperature device has been opened. 476 */ 477 478 static int wdt_temp_open(struct inode *inode, struct file *file) 479 { 480 return stream_open(inode, file); 481 } 482 483 /** 484 * wdt_temp_release: 485 * @inode: inode to board 486 * @file: file handle to board 487 * 488 * The temperature device has been closed. 489 */ 490 491 static int wdt_temp_release(struct inode *inode, struct file *file) 492 { 493 return 0; 494 } 495 496 /** 497 * notify_sys: 498 * @this: our notifier block 499 * @code: the event being reported 500 * @unused: unused 501 * 502 * Our notifier is called on system shutdowns. We want to turn the card 503 * off at reboot otherwise the machine will reboot again during memory 504 * test or worse yet during the following fsck. This would suck, in fact 505 * trust me - if it happens it does suck. 506 */ 507 508 static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 509 void *unused) 510 { 511 if (code == SYS_DOWN || code == SYS_HALT) 512 wdt_stop(); 513 return NOTIFY_DONE; 514 } 515 516 /* 517 * Kernel Interfaces 518 */ 519 520 521 static const struct file_operations wdt_fops = { 522 .owner = THIS_MODULE, 523 .llseek = no_llseek, 524 .write = wdt_write, 525 .unlocked_ioctl = wdt_ioctl, 526 .compat_ioctl = compat_ptr_ioctl, 527 .open = wdt_open, 528 .release = wdt_release, 529 }; 530 531 static struct miscdevice wdt_miscdev = { 532 .minor = WATCHDOG_MINOR, 533 .name = "watchdog", 534 .fops = &wdt_fops, 535 }; 536 537 static const struct file_operations wdt_temp_fops = { 538 .owner = THIS_MODULE, 539 .llseek = no_llseek, 540 .read = wdt_temp_read, 541 .open = wdt_temp_open, 542 .release = wdt_temp_release, 543 }; 544 545 static struct miscdevice temp_miscdev = { 546 .minor = TEMP_MINOR, 547 .name = "temperature", 548 .fops = &wdt_temp_fops, 549 }; 550 551 /* 552 * The WDT card needs to learn about soft shutdowns in order to 553 * turn the timebomb registers off. 554 */ 555 556 static struct notifier_block wdt_notifier = { 557 .notifier_call = wdt_notify_sys, 558 }; 559 560 /** 561 * cleanup_module: 562 * 563 * Unload the watchdog. You cannot do this with any file handles open. 564 * If your watchdog is set to continue ticking on close and you unload 565 * it, well it keeps ticking. We won't get the interrupt but the board 566 * will not touch PC memory so all is fine. You just have to load a new 567 * module in 60 seconds or reboot. 568 */ 569 570 static void __exit wdt_exit(void) 571 { 572 misc_deregister(&wdt_miscdev); 573 if (type == 501) 574 misc_deregister(&temp_miscdev); 575 unregister_reboot_notifier(&wdt_notifier); 576 free_irq(irq, NULL); 577 release_region(io, 8); 578 } 579 580 /** 581 * wdt_init: 582 * 583 * Set up the WDT watchdog board. All we have to do is grab the 584 * resources we require and bitch if anyone beat us to them. 585 * The open() function will actually kick the board off. 586 */ 587 588 static int __init wdt_init(void) 589 { 590 int ret; 591 592 if (type != 500 && type != 501) { 593 pr_err("unknown card type '%d'\n", type); 594 return -ENODEV; 595 } 596 597 /* Check that the heartbeat value is within it's range; 598 if not reset to the default */ 599 if (wdt_set_heartbeat(heartbeat)) { 600 wdt_set_heartbeat(WD_TIMO); 601 pr_info("heartbeat value must be 0 < heartbeat < 65536, using %d\n", 602 WD_TIMO); 603 } 604 605 if (!request_region(io, 8, "wdt501p")) { 606 pr_err("I/O address 0x%04x already in use\n", io); 607 ret = -EBUSY; 608 goto out; 609 } 610 611 ret = request_irq(irq, wdt_interrupt, 0, "wdt501p", NULL); 612 if (ret) { 613 pr_err("IRQ %d is not free\n", irq); 614 goto outreg; 615 } 616 617 ret = register_reboot_notifier(&wdt_notifier); 618 if (ret) { 619 pr_err("cannot register reboot notifier (err=%d)\n", ret); 620 goto outirq; 621 } 622 623 if (type == 501) { 624 ret = misc_register(&temp_miscdev); 625 if (ret) { 626 pr_err("cannot register miscdev on minor=%d (err=%d)\n", 627 TEMP_MINOR, ret); 628 goto outrbt; 629 } 630 } 631 632 ret = misc_register(&wdt_miscdev); 633 if (ret) { 634 pr_err("cannot register miscdev on minor=%d (err=%d)\n", 635 WATCHDOG_MINOR, ret); 636 goto outmisc; 637 } 638 639 pr_info("WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n", 640 io, irq, heartbeat, nowayout); 641 if (type == 501) 642 pr_info("Fan Tachometer is %s\n", 643 tachometer ? "Enabled" : "Disabled"); 644 return 0; 645 646 outmisc: 647 if (type == 501) 648 misc_deregister(&temp_miscdev); 649 outrbt: 650 unregister_reboot_notifier(&wdt_notifier); 651 outirq: 652 free_irq(irq, NULL); 653 outreg: 654 release_region(io, 8); 655 out: 656 return ret; 657 } 658 659 module_init(wdt_init); 660 module_exit(wdt_exit); 661 662 MODULE_AUTHOR("Alan Cox"); 663 MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)"); 664 MODULE_LICENSE("GPL"); 665