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 #define WDRTAS_SP_SPI_LEN 4 110 111 /** 112 * wdrtas_get_interval - returns the current watchdog interval 113 * @fallback_value: value (in seconds) to use, if the RTAS call fails 114 * 115 * returns the interval 116 * 117 * wdrtas_get_interval returns the current watchdog keepalive interval 118 * as reported by the RTAS function ibm,get-system-parameter. The unit 119 * of the return value is seconds. 120 */ 121 static int wdrtas_get_interval(int fallback_value) 122 { 123 long result; 124 char value[WDRTAS_SP_SPI_LEN]; 125 126 spin_lock(&rtas_data_buf_lock); 127 memset(rtas_data_buf, 0, WDRTAS_SP_SPI_LEN); 128 result = rtas_call(wdrtas_token_get_sp, 3, 1, NULL, 129 WDRTAS_SP_SPI, __pa(rtas_data_buf), 130 WDRTAS_SP_SPI_LEN); 131 132 memcpy(value, rtas_data_buf, WDRTAS_SP_SPI_LEN); 133 spin_unlock(&rtas_data_buf_lock); 134 135 if (value[0] != 0 || value[1] != 2 || value[3] != 0 || result < 0) { 136 printk(KERN_WARNING "wdrtas: could not get sp_spi watchdog " 137 "timeout (%li). Continuing\n", result); 138 return fallback_value; 139 } 140 141 /* rtas uses minutes */ 142 return ((int)value[2]) * 60; 143 } 144 145 /** 146 * wdrtas_timer_start - starts watchdog 147 * 148 * wdrtas_timer_start starts the watchdog by calling the RTAS function 149 * set-interval (surveillance) 150 */ 151 static void wdrtas_timer_start(void) 152 { 153 wdrtas_set_interval(wdrtas_interval); 154 } 155 156 /** 157 * wdrtas_timer_stop - stops watchdog 158 * 159 * wdrtas_timer_stop stops the watchdog timer by calling the RTAS function 160 * set-interval (surveillance) 161 */ 162 static void wdrtas_timer_stop(void) 163 { 164 wdrtas_set_interval(0); 165 } 166 167 /** 168 * wdrtas_log_scanned_event - logs an event we received during keepalive 169 * 170 * wdrtas_log_scanned_event prints a message to the log buffer dumping 171 * the results of the last event-scan call 172 */ 173 static void wdrtas_log_scanned_event(void) 174 { 175 int i; 176 177 for (i = 0; i < WDRTAS_LOGBUFFER_LEN; i += 16) 178 printk(KERN_INFO "wdrtas: dumping event (line %i/%i), data = " 179 "%02x %02x %02x %02x %02x %02x %02x %02x " 180 "%02x %02x %02x %02x %02x %02x %02x %02x\n", 181 (i / 16) + 1, (WDRTAS_LOGBUFFER_LEN / 16), 182 wdrtas_logbuffer[i + 0], wdrtas_logbuffer[i + 1], 183 wdrtas_logbuffer[i + 2], wdrtas_logbuffer[i + 3], 184 wdrtas_logbuffer[i + 4], wdrtas_logbuffer[i + 5], 185 wdrtas_logbuffer[i + 6], wdrtas_logbuffer[i + 7], 186 wdrtas_logbuffer[i + 8], wdrtas_logbuffer[i + 9], 187 wdrtas_logbuffer[i + 10], wdrtas_logbuffer[i + 11], 188 wdrtas_logbuffer[i + 12], wdrtas_logbuffer[i + 13], 189 wdrtas_logbuffer[i + 14], wdrtas_logbuffer[i + 15]); 190 } 191 192 /** 193 * wdrtas_timer_keepalive - resets watchdog timer to keep system alive 194 * 195 * wdrtas_timer_keepalive restarts the watchdog timer by calling the 196 * RTAS function event-scan and repeats these calls as long as there are 197 * events available. All events will be dumped. 198 */ 199 static void wdrtas_timer_keepalive(void) 200 { 201 long result; 202 203 do { 204 result = rtas_call(wdrtas_token_event_scan, 4, 1, NULL, 205 RTAS_EVENT_SCAN_ALL_EVENTS, 0, 206 (void *)__pa(wdrtas_logbuffer), 207 WDRTAS_LOGBUFFER_LEN); 208 if (result < 0) 209 printk(KERN_ERR "wdrtas: event-scan failed: %li\n", 210 result); 211 if (result == 0) 212 wdrtas_log_scanned_event(); 213 } while (result == 0); 214 } 215 216 /** 217 * wdrtas_get_temperature - returns current temperature 218 * 219 * returns temperature or <0 on failures 220 * 221 * wdrtas_get_temperature returns the current temperature in Fahrenheit. It 222 * uses the RTAS call get-sensor-state, token 3 to do so 223 */ 224 static int wdrtas_get_temperature(void) 225 { 226 long result; 227 int temperature = 0; 228 229 result = rtas_call(wdrtas_token_get_sensor_state, 2, 2, 230 (void *)__pa(&temperature), 231 WDRTAS_THERMAL_SENSOR, 0); 232 233 if (result < 0) 234 printk(KERN_WARNING "wdrtas: reading the thermal sensor " 235 "faild: %li\n", result); 236 else 237 temperature = ((temperature * 9) / 5) + 32; /* fahrenheit */ 238 239 return temperature; 240 } 241 242 /** 243 * wdrtas_get_status - returns the status of the watchdog 244 * 245 * returns a bitmask of defines WDIOF_... as defined in 246 * include/linux/watchdog.h 247 */ 248 static int wdrtas_get_status(void) 249 { 250 return 0; /* TODO */ 251 } 252 253 /** 254 * wdrtas_get_boot_status - returns the reason for the last boot 255 * 256 * returns a bitmask of defines WDIOF_... as defined in 257 * include/linux/watchdog.h, indicating why the watchdog rebooted the system 258 */ 259 static int wdrtas_get_boot_status(void) 260 { 261 return 0; /* TODO */ 262 } 263 264 /*** watchdog API and operations stuff */ 265 266 /* wdrtas_write - called when watchdog device is written to 267 * @file: file structure 268 * @buf: user buffer with data 269 * @len: amount to data written 270 * @ppos: position in file 271 * 272 * returns the number of successfully processed characters, which is always 273 * the number of bytes passed to this function 274 * 275 * wdrtas_write processes all the data given to it and looks for the magic 276 * character 'V'. This character allows the watchdog device to be closed 277 * properly. 278 */ 279 static ssize_t wdrtas_write(struct file *file, const char __user *buf, 280 size_t len, loff_t *ppos) 281 { 282 int i; 283 char c; 284 285 if (!len) 286 goto out; 287 288 if (!wdrtas_nowayout) { 289 wdrtas_expect_close = 0; 290 /* look for 'V' */ 291 for (i = 0; i < len; i++) { 292 if (get_user(c, buf + i)) 293 return -EFAULT; 294 /* allow to close device */ 295 if (c == 'V') 296 wdrtas_expect_close = WDRTAS_MAGIC_CHAR; 297 } 298 } 299 300 wdrtas_timer_keepalive(); 301 302 out: 303 return len; 304 } 305 306 /** 307 * wdrtas_ioctl - ioctl function for the watchdog device 308 * @file: file structure 309 * @cmd: command for ioctl 310 * @arg: argument pointer 311 * 312 * returns 0 on success, <0 on failure 313 * 314 * wdrtas_ioctl implements the watchdog API ioctls 315 */ 316 317 static long wdrtas_ioctl(struct file *file, unsigned int cmd, 318 unsigned long arg) 319 { 320 int __user *argp = (void __user *)arg; 321 int i; 322 static struct watchdog_info wdinfo = { 323 .options = WDRTAS_SUPPORTED_MASK, 324 .firmware_version = 0, 325 .identity = "wdrtas", 326 }; 327 328 switch (cmd) { 329 case WDIOC_GETSUPPORT: 330 if (copy_to_user(argp, &wdinfo, sizeof(wdinfo))) 331 return -EFAULT; 332 return 0; 333 334 case WDIOC_GETSTATUS: 335 i = wdrtas_get_status(); 336 return put_user(i, argp); 337 338 case WDIOC_GETBOOTSTATUS: 339 i = wdrtas_get_boot_status(); 340 return put_user(i, argp); 341 342 case WDIOC_GETTEMP: 343 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) 344 return -EOPNOTSUPP; 345 346 i = wdrtas_get_temperature(); 347 return put_user(i, argp); 348 349 case WDIOC_SETOPTIONS: 350 if (get_user(i, argp)) 351 return -EFAULT; 352 if (i & WDIOS_DISABLECARD) 353 wdrtas_timer_stop(); 354 if (i & WDIOS_ENABLECARD) { 355 wdrtas_timer_keepalive(); 356 wdrtas_timer_start(); 357 } 358 /* not implemented. Done by H8 359 if (i & WDIOS_TEMPPANIC) { 360 } */ 361 return 0; 362 363 case WDIOC_KEEPALIVE: 364 wdrtas_timer_keepalive(); 365 return 0; 366 367 case WDIOC_SETTIMEOUT: 368 if (get_user(i, argp)) 369 return -EFAULT; 370 371 if (wdrtas_set_interval(i)) 372 return -EINVAL; 373 374 wdrtas_timer_keepalive(); 375 376 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) 377 wdrtas_interval = i; 378 else 379 wdrtas_interval = wdrtas_get_interval(i); 380 /* fallthrough */ 381 382 case WDIOC_GETTIMEOUT: 383 return put_user(wdrtas_interval, argp); 384 385 default: 386 return -ENOTTY; 387 } 388 } 389 390 /** 391 * wdrtas_open - open function of watchdog device 392 * @inode: inode structure 393 * @file: file structure 394 * 395 * returns 0 on success, -EBUSY if the file has been opened already, <0 on 396 * other failures 397 * 398 * function called when watchdog device is opened 399 */ 400 static int wdrtas_open(struct inode *inode, struct file *file) 401 { 402 /* only open once */ 403 if (atomic_inc_return(&wdrtas_miscdev_open) > 1) { 404 atomic_dec(&wdrtas_miscdev_open); 405 return -EBUSY; 406 } 407 408 wdrtas_timer_start(); 409 wdrtas_timer_keepalive(); 410 411 return nonseekable_open(inode, file); 412 } 413 414 /** 415 * wdrtas_close - close function of watchdog device 416 * @inode: inode structure 417 * @file: file structure 418 * 419 * returns 0 on success 420 * 421 * close function. Always succeeds 422 */ 423 static int wdrtas_close(struct inode *inode, struct file *file) 424 { 425 /* only stop watchdog, if this was announced using 'V' before */ 426 if (wdrtas_expect_close == WDRTAS_MAGIC_CHAR) 427 wdrtas_timer_stop(); 428 else { 429 printk(KERN_WARNING "wdrtas: got unexpected close. Watchdog " 430 "not stopped.\n"); 431 wdrtas_timer_keepalive(); 432 } 433 434 wdrtas_expect_close = 0; 435 atomic_dec(&wdrtas_miscdev_open); 436 return 0; 437 } 438 439 /** 440 * wdrtas_temp_read - gives back the temperature in fahrenheit 441 * @file: file structure 442 * @buf: user buffer 443 * @count: number of bytes to be read 444 * @ppos: position in file 445 * 446 * returns always 1 or -EFAULT in case of user space copy failures, <0 on 447 * other failures 448 * 449 * wdrtas_temp_read gives the temperature to the users by copying this 450 * value as one byte into the user space buffer. The unit is Fahrenheit... 451 */ 452 static ssize_t wdrtas_temp_read(struct file *file, char __user *buf, 453 size_t count, loff_t *ppos) 454 { 455 int temperature = 0; 456 457 temperature = wdrtas_get_temperature(); 458 if (temperature < 0) 459 return temperature; 460 461 if (copy_to_user(buf, &temperature, 1)) 462 return -EFAULT; 463 464 return 1; 465 } 466 467 /** 468 * wdrtas_temp_open - open function of temperature device 469 * @inode: inode structure 470 * @file: file structure 471 * 472 * returns 0 on success, <0 on failure 473 * 474 * function called when temperature device is opened 475 */ 476 static int wdrtas_temp_open(struct inode *inode, struct file *file) 477 { 478 return nonseekable_open(inode, file); 479 } 480 481 /** 482 * wdrtas_temp_close - close function of temperature device 483 * @inode: inode structure 484 * @file: file structure 485 * 486 * returns 0 on success 487 * 488 * close function. Always succeeds 489 */ 490 static int wdrtas_temp_close(struct inode *inode, struct file *file) 491 { 492 return 0; 493 } 494 495 /** 496 * wdrtas_reboot - reboot notifier function 497 * @nb: notifier block structure 498 * @code: reboot code 499 * @ptr: unused 500 * 501 * returns NOTIFY_DONE 502 * 503 * wdrtas_reboot stops the watchdog in case of a reboot 504 */ 505 static int wdrtas_reboot(struct notifier_block *this, 506 unsigned long code, void *ptr) 507 { 508 if (code == SYS_DOWN || code == SYS_HALT) 509 wdrtas_timer_stop(); 510 511 return NOTIFY_DONE; 512 } 513 514 /*** initialization stuff */ 515 516 static const struct file_operations wdrtas_fops = { 517 .owner = THIS_MODULE, 518 .llseek = no_llseek, 519 .write = wdrtas_write, 520 .unlocked_ioctl = wdrtas_ioctl, 521 .open = wdrtas_open, 522 .release = wdrtas_close, 523 }; 524 525 static struct miscdevice wdrtas_miscdev = { 526 .minor = WATCHDOG_MINOR, 527 .name = "watchdog", 528 .fops = &wdrtas_fops, 529 }; 530 531 static const struct file_operations wdrtas_temp_fops = { 532 .owner = THIS_MODULE, 533 .llseek = no_llseek, 534 .read = wdrtas_temp_read, 535 .open = wdrtas_temp_open, 536 .release = wdrtas_temp_close, 537 }; 538 539 static struct miscdevice wdrtas_tempdev = { 540 .minor = TEMP_MINOR, 541 .name = "temperature", 542 .fops = &wdrtas_temp_fops, 543 }; 544 545 static struct notifier_block wdrtas_notifier = { 546 .notifier_call = wdrtas_reboot, 547 }; 548 549 /** 550 * wdrtas_get_tokens - reads in RTAS tokens 551 * 552 * returns 0 on succes, <0 on failure 553 * 554 * wdrtas_get_tokens reads in the tokens for the RTAS calls used in 555 * this watchdog driver. It tolerates, if "get-sensor-state" and 556 * "ibm,get-system-parameter" are not available. 557 */ 558 static int wdrtas_get_tokens(void) 559 { 560 wdrtas_token_get_sensor_state = rtas_token("get-sensor-state"); 561 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) { 562 printk(KERN_WARNING "wdrtas: couldn't get token for " 563 "get-sensor-state. Trying to continue without " 564 "temperature support.\n"); 565 } 566 567 wdrtas_token_get_sp = rtas_token("ibm,get-system-parameter"); 568 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) { 569 printk(KERN_WARNING "wdrtas: couldn't get token for " 570 "ibm,get-system-parameter. Trying to continue with " 571 "a default timeout value of %i seconds.\n", 572 WDRTAS_DEFAULT_INTERVAL); 573 } 574 575 wdrtas_token_set_indicator = rtas_token("set-indicator"); 576 if (wdrtas_token_set_indicator == RTAS_UNKNOWN_SERVICE) { 577 printk(KERN_ERR "wdrtas: couldn't get token for " 578 "set-indicator. Terminating watchdog code.\n"); 579 return -EIO; 580 } 581 582 wdrtas_token_event_scan = rtas_token("event-scan"); 583 if (wdrtas_token_event_scan == RTAS_UNKNOWN_SERVICE) { 584 printk(KERN_ERR "wdrtas: couldn't get token for event-scan. " 585 "Terminating watchdog code.\n"); 586 return -EIO; 587 } 588 589 return 0; 590 } 591 592 /** 593 * wdrtas_unregister_devs - unregisters the misc dev handlers 594 * 595 * wdrtas_register_devs unregisters the watchdog and temperature watchdog 596 * misc devs 597 */ 598 static void wdrtas_unregister_devs(void) 599 { 600 misc_deregister(&wdrtas_miscdev); 601 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) 602 misc_deregister(&wdrtas_tempdev); 603 } 604 605 /** 606 * wdrtas_register_devs - registers the misc dev handlers 607 * 608 * returns 0 on succes, <0 on failure 609 * 610 * wdrtas_register_devs registers the watchdog and temperature watchdog 611 * misc devs 612 */ 613 static int wdrtas_register_devs(void) 614 { 615 int result; 616 617 result = misc_register(&wdrtas_miscdev); 618 if (result) { 619 printk(KERN_ERR "wdrtas: couldn't register watchdog misc " 620 "device. Terminating watchdog code.\n"); 621 return result; 622 } 623 624 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) { 625 result = misc_register(&wdrtas_tempdev); 626 if (result) { 627 printk(KERN_WARNING "wdrtas: couldn't register " 628 "watchdog temperature misc device. Continuing " 629 "without temperature support.\n"); 630 wdrtas_token_get_sensor_state = RTAS_UNKNOWN_SERVICE; 631 } 632 } 633 634 return 0; 635 } 636 637 /** 638 * wdrtas_init - init function of the watchdog driver 639 * 640 * returns 0 on succes, <0 on failure 641 * 642 * registers the file handlers and the reboot notifier 643 */ 644 static int __init wdrtas_init(void) 645 { 646 if (wdrtas_get_tokens()) 647 return -ENODEV; 648 649 if (wdrtas_register_devs()) 650 return -ENODEV; 651 652 if (register_reboot_notifier(&wdrtas_notifier)) { 653 printk(KERN_ERR "wdrtas: could not register reboot notifier. " 654 "Terminating watchdog code.\n"); 655 wdrtas_unregister_devs(); 656 return -ENODEV; 657 } 658 659 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) 660 wdrtas_interval = WDRTAS_DEFAULT_INTERVAL; 661 else 662 wdrtas_interval = wdrtas_get_interval(WDRTAS_DEFAULT_INTERVAL); 663 664 return 0; 665 } 666 667 /** 668 * wdrtas_exit - exit function of the watchdog driver 669 * 670 * unregisters the file handlers and the reboot notifier 671 */ 672 static void __exit wdrtas_exit(void) 673 { 674 if (!wdrtas_nowayout) 675 wdrtas_timer_stop(); 676 677 wdrtas_unregister_devs(); 678 679 unregister_reboot_notifier(&wdrtas_notifier); 680 } 681 682 module_init(wdrtas_init); 683 module_exit(wdrtas_exit); 684