1 /* 2 * FIXME: add wdrtas_get_status and wdrtas_get_boot_status as soon as 3 * RTAS calls are available 4 */ 5 6 /* 7 * RTAS watchdog driver 8 * 9 * (C) Copyright IBM Corp. 2005 10 * device driver to exploit watchdog RTAS functions 11 * 12 * Authors : Utz Bacher <utz.bacher@de.ibm.com> 13 * 14 * This program is free software; you can redistribute it and/or modify 15 * it under the terms of the GNU General Public License as published by 16 * the Free Software Foundation; either version 2, or (at your option) 17 * any later version. 18 * 19 * This program is distributed in the hope that it will be useful, 20 * but WITHOUT ANY WARRANTY; without even the implied warranty of 21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 22 * GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with this program; if not, write to the Free Software 26 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 27 */ 28 29 #include <linux/fs.h> 30 #include <linux/init.h> 31 #include <linux/kernel.h> 32 #include <linux/miscdevice.h> 33 #include <linux/module.h> 34 #include <linux/notifier.h> 35 #include <linux/reboot.h> 36 #include <linux/types.h> 37 #include <linux/watchdog.h> 38 #include <linux/uaccess.h> 39 40 #include <asm/rtas.h> 41 42 #define WDRTAS_MAGIC_CHAR 42 43 #define WDRTAS_SUPPORTED_MASK (WDIOF_SETTIMEOUT | \ 44 WDIOF_MAGICCLOSE) 45 46 MODULE_AUTHOR("Utz Bacher <utz.bacher@de.ibm.com>"); 47 MODULE_DESCRIPTION("RTAS watchdog driver"); 48 MODULE_LICENSE("GPL"); 49 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 50 MODULE_ALIAS_MISCDEV(TEMP_MINOR); 51 52 #ifdef CONFIG_WATCHDOG_NOWAYOUT 53 static int wdrtas_nowayout = 1; 54 #else 55 static int wdrtas_nowayout = 0; 56 #endif 57 58 static atomic_t wdrtas_miscdev_open = ATOMIC_INIT(0); 59 static char wdrtas_expect_close; 60 61 static int wdrtas_interval; 62 63 #define WDRTAS_THERMAL_SENSOR 3 64 static int wdrtas_token_get_sensor_state; 65 #define WDRTAS_SURVEILLANCE_IND 9000 66 static int wdrtas_token_set_indicator; 67 #define WDRTAS_SP_SPI 28 68 static int wdrtas_token_get_sp; 69 static int wdrtas_token_event_scan; 70 71 #define WDRTAS_DEFAULT_INTERVAL 300 72 73 #define WDRTAS_LOGBUFFER_LEN 128 74 static char wdrtas_logbuffer[WDRTAS_LOGBUFFER_LEN]; 75 76 77 /*** watchdog access functions */ 78 79 /** 80 * wdrtas_set_interval - sets the watchdog interval 81 * @interval: new interval 82 * 83 * returns 0 on success, <0 on failures 84 * 85 * wdrtas_set_interval sets the watchdog keepalive interval by calling the 86 * RTAS function set-indicator (surveillance). The unit of interval is 87 * seconds. 88 */ 89 90 static int wdrtas_set_interval(int interval) 91 { 92 long result; 93 static int print_msg = 10; 94 95 /* rtas uses minutes */ 96 interval = (interval + 59) / 60; 97 98 result = rtas_call(wdrtas_token_set_indicator, 3, 1, NULL, 99 WDRTAS_SURVEILLANCE_IND, 0, interval); 100 if (result < 0 && print_msg) { 101 printk(KERN_ERR "wdrtas: setting the watchdog to %i " 102 "timeout failed: %li\n", interval, result); 103 print_msg--; 104 } 105 106 return result; 107 } 108 109 /** 110 * wdrtas_get_interval - returns the current watchdog interval 111 * @fallback_value: value (in seconds) to use, if the RTAS call fails 112 * 113 * returns the interval 114 * 115 * wdrtas_get_interval returns the current watchdog keepalive interval 116 * as reported by the RTAS function ibm,get-system-parameter. The unit 117 * of the return value is seconds. 118 */ 119 static int wdrtas_get_interval(int fallback_value) 120 { 121 long result; 122 char value[4]; 123 124 result = rtas_call(wdrtas_token_get_sp, 3, 1, NULL, 125 WDRTAS_SP_SPI, (void *)__pa(&value), 4); 126 if (value[0] != 0 || value[1] != 2 || value[3] != 0 || result < 0) { 127 printk(KERN_WARNING "wdrtas: could not get sp_spi watchdog " 128 "timeout (%li). Continuing\n", result); 129 return fallback_value; 130 } 131 132 /* rtas uses minutes */ 133 return ((int)value[2]) * 60; 134 } 135 136 /** 137 * wdrtas_timer_start - starts watchdog 138 * 139 * wdrtas_timer_start starts the watchdog by calling the RTAS function 140 * set-interval (surveillance) 141 */ 142 static void wdrtas_timer_start(void) 143 { 144 wdrtas_set_interval(wdrtas_interval); 145 } 146 147 /** 148 * wdrtas_timer_stop - stops watchdog 149 * 150 * wdrtas_timer_stop stops the watchdog timer by calling the RTAS function 151 * set-interval (surveillance) 152 */ 153 static void wdrtas_timer_stop(void) 154 { 155 wdrtas_set_interval(0); 156 } 157 158 /** 159 * wdrtas_log_scanned_event - logs an event we received during keepalive 160 * 161 * wdrtas_log_scanned_event prints a message to the log buffer dumping 162 * the results of the last event-scan call 163 */ 164 static void wdrtas_log_scanned_event(void) 165 { 166 int i; 167 168 for (i = 0; i < WDRTAS_LOGBUFFER_LEN; i += 16) 169 printk(KERN_INFO "wdrtas: dumping event (line %i/%i), data = " 170 "%02x %02x %02x %02x %02x %02x %02x %02x " 171 "%02x %02x %02x %02x %02x %02x %02x %02x\n", 172 (i / 16) + 1, (WDRTAS_LOGBUFFER_LEN / 16), 173 wdrtas_logbuffer[i + 0], wdrtas_logbuffer[i + 1], 174 wdrtas_logbuffer[i + 2], wdrtas_logbuffer[i + 3], 175 wdrtas_logbuffer[i + 4], wdrtas_logbuffer[i + 5], 176 wdrtas_logbuffer[i + 6], wdrtas_logbuffer[i + 7], 177 wdrtas_logbuffer[i + 8], wdrtas_logbuffer[i + 9], 178 wdrtas_logbuffer[i + 10], wdrtas_logbuffer[i + 11], 179 wdrtas_logbuffer[i + 12], wdrtas_logbuffer[i + 13], 180 wdrtas_logbuffer[i + 14], wdrtas_logbuffer[i + 15]); 181 } 182 183 /** 184 * wdrtas_timer_keepalive - resets watchdog timer to keep system alive 185 * 186 * wdrtas_timer_keepalive restarts the watchdog timer by calling the 187 * RTAS function event-scan and repeats these calls as long as there are 188 * events available. All events will be dumped. 189 */ 190 static void wdrtas_timer_keepalive(void) 191 { 192 long result; 193 194 do { 195 result = rtas_call(wdrtas_token_event_scan, 4, 1, NULL, 196 RTAS_EVENT_SCAN_ALL_EVENTS, 0, 197 (void *)__pa(wdrtas_logbuffer), 198 WDRTAS_LOGBUFFER_LEN); 199 if (result < 0) 200 printk(KERN_ERR "wdrtas: event-scan failed: %li\n", 201 result); 202 if (result == 0) 203 wdrtas_log_scanned_event(); 204 } while (result == 0); 205 } 206 207 /** 208 * wdrtas_get_temperature - returns current temperature 209 * 210 * returns temperature or <0 on failures 211 * 212 * wdrtas_get_temperature returns the current temperature in Fahrenheit. It 213 * uses the RTAS call get-sensor-state, token 3 to do so 214 */ 215 static int wdrtas_get_temperature(void) 216 { 217 long result; 218 int temperature = 0; 219 220 result = rtas_call(wdrtas_token_get_sensor_state, 2, 2, 221 (void *)__pa(&temperature), 222 WDRTAS_THERMAL_SENSOR, 0); 223 224 if (result < 0) 225 printk(KERN_WARNING "wdrtas: reading the thermal sensor " 226 "faild: %li\n", result); 227 else 228 temperature = ((temperature * 9) / 5) + 32; /* fahrenheit */ 229 230 return temperature; 231 } 232 233 /** 234 * wdrtas_get_status - returns the status of the watchdog 235 * 236 * returns a bitmask of defines WDIOF_... as defined in 237 * include/linux/watchdog.h 238 */ 239 static int wdrtas_get_status(void) 240 { 241 return 0; /* TODO */ 242 } 243 244 /** 245 * wdrtas_get_boot_status - returns the reason for the last boot 246 * 247 * returns a bitmask of defines WDIOF_... as defined in 248 * include/linux/watchdog.h, indicating why the watchdog rebooted the system 249 */ 250 static int wdrtas_get_boot_status(void) 251 { 252 return 0; /* TODO */ 253 } 254 255 /*** watchdog API and operations stuff */ 256 257 /* wdrtas_write - called when watchdog device is written to 258 * @file: file structure 259 * @buf: user buffer with data 260 * @len: amount to data written 261 * @ppos: position in file 262 * 263 * returns the number of successfully processed characters, which is always 264 * the number of bytes passed to this function 265 * 266 * wdrtas_write processes all the data given to it and looks for the magic 267 * character 'V'. This character allows the watchdog device to be closed 268 * properly. 269 */ 270 static ssize_t wdrtas_write(struct file *file, const char __user *buf, 271 size_t len, loff_t *ppos) 272 { 273 int i; 274 char c; 275 276 if (!len) 277 goto out; 278 279 if (!wdrtas_nowayout) { 280 wdrtas_expect_close = 0; 281 /* look for 'V' */ 282 for (i = 0; i < len; i++) { 283 if (get_user(c, buf + i)) 284 return -EFAULT; 285 /* allow to close device */ 286 if (c == 'V') 287 wdrtas_expect_close = WDRTAS_MAGIC_CHAR; 288 } 289 } 290 291 wdrtas_timer_keepalive(); 292 293 out: 294 return len; 295 } 296 297 /** 298 * wdrtas_ioctl - ioctl function for the watchdog device 299 * @file: file structure 300 * @cmd: command for ioctl 301 * @arg: argument pointer 302 * 303 * returns 0 on success, <0 on failure 304 * 305 * wdrtas_ioctl implements the watchdog API ioctls 306 */ 307 308 static long wdrtas_ioctl(struct file *file, unsigned int cmd, 309 unsigned long arg) 310 { 311 int __user *argp = (void __user *)arg; 312 int i; 313 static struct watchdog_info wdinfo = { 314 .options = WDRTAS_SUPPORTED_MASK, 315 .firmware_version = 0, 316 .identity = "wdrtas", 317 }; 318 319 switch (cmd) { 320 case WDIOC_GETSUPPORT: 321 if (copy_to_user(argp, &wdinfo, sizeof(wdinfo))) 322 return -EFAULT; 323 return 0; 324 325 case WDIOC_GETSTATUS: 326 i = wdrtas_get_status(); 327 return put_user(i, argp); 328 329 case WDIOC_GETBOOTSTATUS: 330 i = wdrtas_get_boot_status(); 331 return put_user(i, argp); 332 333 case WDIOC_GETTEMP: 334 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) 335 return -EOPNOTSUPP; 336 337 i = wdrtas_get_temperature(); 338 return put_user(i, argp); 339 340 case WDIOC_SETOPTIONS: 341 if (get_user(i, argp)) 342 return -EFAULT; 343 if (i & WDIOS_DISABLECARD) 344 wdrtas_timer_stop(); 345 if (i & WDIOS_ENABLECARD) { 346 wdrtas_timer_keepalive(); 347 wdrtas_timer_start(); 348 } 349 /* not implemented. Done by H8 350 if (i & WDIOS_TEMPPANIC) { 351 } */ 352 return 0; 353 354 case WDIOC_KEEPALIVE: 355 wdrtas_timer_keepalive(); 356 return 0; 357 358 case WDIOC_SETTIMEOUT: 359 if (get_user(i, argp)) 360 return -EFAULT; 361 362 if (wdrtas_set_interval(i)) 363 return -EINVAL; 364 365 wdrtas_timer_keepalive(); 366 367 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) 368 wdrtas_interval = i; 369 else 370 wdrtas_interval = wdrtas_get_interval(i); 371 /* fallthrough */ 372 373 case WDIOC_GETTIMEOUT: 374 return put_user(wdrtas_interval, argp); 375 376 default: 377 return -ENOTTY; 378 } 379 } 380 381 /** 382 * wdrtas_open - open function of watchdog device 383 * @inode: inode structure 384 * @file: file structure 385 * 386 * returns 0 on success, -EBUSY if the file has been opened already, <0 on 387 * other failures 388 * 389 * function called when watchdog device is opened 390 */ 391 static int wdrtas_open(struct inode *inode, struct file *file) 392 { 393 /* only open once */ 394 if (atomic_inc_return(&wdrtas_miscdev_open) > 1) { 395 atomic_dec(&wdrtas_miscdev_open); 396 return -EBUSY; 397 } 398 399 wdrtas_timer_start(); 400 wdrtas_timer_keepalive(); 401 402 return nonseekable_open(inode, file); 403 } 404 405 /** 406 * wdrtas_close - close function of watchdog device 407 * @inode: inode structure 408 * @file: file structure 409 * 410 * returns 0 on success 411 * 412 * close function. Always succeeds 413 */ 414 static int wdrtas_close(struct inode *inode, struct file *file) 415 { 416 /* only stop watchdog, if this was announced using 'V' before */ 417 if (wdrtas_expect_close == WDRTAS_MAGIC_CHAR) 418 wdrtas_timer_stop(); 419 else { 420 printk(KERN_WARNING "wdrtas: got unexpected close. Watchdog " 421 "not stopped.\n"); 422 wdrtas_timer_keepalive(); 423 } 424 425 wdrtas_expect_close = 0; 426 atomic_dec(&wdrtas_miscdev_open); 427 return 0; 428 } 429 430 /** 431 * wdrtas_temp_read - gives back the temperature in fahrenheit 432 * @file: file structure 433 * @buf: user buffer 434 * @count: number of bytes to be read 435 * @ppos: position in file 436 * 437 * returns always 1 or -EFAULT in case of user space copy failures, <0 on 438 * other failures 439 * 440 * wdrtas_temp_read gives the temperature to the users by copying this 441 * value as one byte into the user space buffer. The unit is Fahrenheit... 442 */ 443 static ssize_t wdrtas_temp_read(struct file *file, char __user *buf, 444 size_t count, loff_t *ppos) 445 { 446 int temperature = 0; 447 448 temperature = wdrtas_get_temperature(); 449 if (temperature < 0) 450 return temperature; 451 452 if (copy_to_user(buf, &temperature, 1)) 453 return -EFAULT; 454 455 return 1; 456 } 457 458 /** 459 * wdrtas_temp_open - open function of temperature device 460 * @inode: inode structure 461 * @file: file structure 462 * 463 * returns 0 on success, <0 on failure 464 * 465 * function called when temperature device is opened 466 */ 467 static int wdrtas_temp_open(struct inode *inode, struct file *file) 468 { 469 return nonseekable_open(inode, file); 470 } 471 472 /** 473 * wdrtas_temp_close - close function of temperature device 474 * @inode: inode structure 475 * @file: file structure 476 * 477 * returns 0 on success 478 * 479 * close function. Always succeeds 480 */ 481 static int wdrtas_temp_close(struct inode *inode, struct file *file) 482 { 483 return 0; 484 } 485 486 /** 487 * wdrtas_reboot - reboot notifier function 488 * @nb: notifier block structure 489 * @code: reboot code 490 * @ptr: unused 491 * 492 * returns NOTIFY_DONE 493 * 494 * wdrtas_reboot stops the watchdog in case of a reboot 495 */ 496 static int wdrtas_reboot(struct notifier_block *this, 497 unsigned long code, void *ptr) 498 { 499 if (code == SYS_DOWN || code == SYS_HALT) 500 wdrtas_timer_stop(); 501 502 return NOTIFY_DONE; 503 } 504 505 /*** initialization stuff */ 506 507 static const struct file_operations wdrtas_fops = { 508 .owner = THIS_MODULE, 509 .llseek = no_llseek, 510 .write = wdrtas_write, 511 .unlocked_ioctl = wdrtas_ioctl, 512 .open = wdrtas_open, 513 .release = wdrtas_close, 514 }; 515 516 static struct miscdevice wdrtas_miscdev = { 517 .minor = WATCHDOG_MINOR, 518 .name = "watchdog", 519 .fops = &wdrtas_fops, 520 }; 521 522 static const struct file_operations wdrtas_temp_fops = { 523 .owner = THIS_MODULE, 524 .llseek = no_llseek, 525 .read = wdrtas_temp_read, 526 .open = wdrtas_temp_open, 527 .release = wdrtas_temp_close, 528 }; 529 530 static struct miscdevice wdrtas_tempdev = { 531 .minor = TEMP_MINOR, 532 .name = "temperature", 533 .fops = &wdrtas_temp_fops, 534 }; 535 536 static struct notifier_block wdrtas_notifier = { 537 .notifier_call = wdrtas_reboot, 538 }; 539 540 /** 541 * wdrtas_get_tokens - reads in RTAS tokens 542 * 543 * returns 0 on succes, <0 on failure 544 * 545 * wdrtas_get_tokens reads in the tokens for the RTAS calls used in 546 * this watchdog driver. It tolerates, if "get-sensor-state" and 547 * "ibm,get-system-parameter" are not available. 548 */ 549 static int wdrtas_get_tokens(void) 550 { 551 wdrtas_token_get_sensor_state = rtas_token("get-sensor-state"); 552 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) { 553 printk(KERN_WARNING "wdrtas: couldn't get token for " 554 "get-sensor-state. Trying to continue without " 555 "temperature support.\n"); 556 } 557 558 wdrtas_token_get_sp = rtas_token("ibm,get-system-parameter"); 559 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) { 560 printk(KERN_WARNING "wdrtas: couldn't get token for " 561 "ibm,get-system-parameter. Trying to continue with " 562 "a default timeout value of %i seconds.\n", 563 WDRTAS_DEFAULT_INTERVAL); 564 } 565 566 wdrtas_token_set_indicator = rtas_token("set-indicator"); 567 if (wdrtas_token_set_indicator == RTAS_UNKNOWN_SERVICE) { 568 printk(KERN_ERR "wdrtas: couldn't get token for " 569 "set-indicator. Terminating watchdog code.\n"); 570 return -EIO; 571 } 572 573 wdrtas_token_event_scan = rtas_token("event-scan"); 574 if (wdrtas_token_event_scan == RTAS_UNKNOWN_SERVICE) { 575 printk(KERN_ERR "wdrtas: couldn't get token for event-scan. " 576 "Terminating watchdog code.\n"); 577 return -EIO; 578 } 579 580 return 0; 581 } 582 583 /** 584 * wdrtas_unregister_devs - unregisters the misc dev handlers 585 * 586 * wdrtas_register_devs unregisters the watchdog and temperature watchdog 587 * misc devs 588 */ 589 static void wdrtas_unregister_devs(void) 590 { 591 misc_deregister(&wdrtas_miscdev); 592 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) 593 misc_deregister(&wdrtas_tempdev); 594 } 595 596 /** 597 * wdrtas_register_devs - registers the misc dev handlers 598 * 599 * returns 0 on succes, <0 on failure 600 * 601 * wdrtas_register_devs registers the watchdog and temperature watchdog 602 * misc devs 603 */ 604 static int wdrtas_register_devs(void) 605 { 606 int result; 607 608 result = misc_register(&wdrtas_miscdev); 609 if (result) { 610 printk(KERN_ERR "wdrtas: couldn't register watchdog misc " 611 "device. Terminating watchdog code.\n"); 612 return result; 613 } 614 615 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) { 616 result = misc_register(&wdrtas_tempdev); 617 if (result) { 618 printk(KERN_WARNING "wdrtas: couldn't register " 619 "watchdog temperature misc device. Continuing " 620 "without temperature support.\n"); 621 wdrtas_token_get_sensor_state = RTAS_UNKNOWN_SERVICE; 622 } 623 } 624 625 return 0; 626 } 627 628 /** 629 * wdrtas_init - init function of the watchdog driver 630 * 631 * returns 0 on succes, <0 on failure 632 * 633 * registers the file handlers and the reboot notifier 634 */ 635 static int __init wdrtas_init(void) 636 { 637 if (wdrtas_get_tokens()) 638 return -ENODEV; 639 640 if (wdrtas_register_devs()) 641 return -ENODEV; 642 643 if (register_reboot_notifier(&wdrtas_notifier)) { 644 printk(KERN_ERR "wdrtas: could not register reboot notifier. " 645 "Terminating watchdog code.\n"); 646 wdrtas_unregister_devs(); 647 return -ENODEV; 648 } 649 650 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) 651 wdrtas_interval = WDRTAS_DEFAULT_INTERVAL; 652 else 653 wdrtas_interval = wdrtas_get_interval(WDRTAS_DEFAULT_INTERVAL); 654 655 return 0; 656 } 657 658 /** 659 * wdrtas_exit - exit function of the watchdog driver 660 * 661 * unregisters the file handlers and the reboot notifier 662 */ 663 static void __exit wdrtas_exit(void) 664 { 665 if (!wdrtas_nowayout) 666 wdrtas_timer_stop(); 667 668 wdrtas_unregister_devs(); 669 670 unregister_reboot_notifier(&wdrtas_notifier); 671 } 672 673 module_init(wdrtas_init); 674 module_exit(wdrtas_exit); 675