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 static int wdrtas_nowayout = WATCHDOG_NOWAYOUT;
53 static atomic_t wdrtas_miscdev_open = ATOMIC_INIT(0);
54 static char wdrtas_expect_close;
55
56 static int wdrtas_interval;
57
58 #define WDRTAS_THERMAL_SENSOR 3
59 static int wdrtas_token_get_sensor_state;
60 #define WDRTAS_SURVEILLANCE_IND 9000
61 static int wdrtas_token_set_indicator;
62 #define WDRTAS_SP_SPI 28
63 static int wdrtas_token_get_sp;
64 static int wdrtas_token_event_scan;
65
66 #define WDRTAS_DEFAULT_INTERVAL 300
67
68 #define WDRTAS_LOGBUFFER_LEN 128
69 static char wdrtas_logbuffer[WDRTAS_LOGBUFFER_LEN];
70
71
72 /*** watchdog access functions */
73
74 /**
75 * wdrtas_set_interval - sets the watchdog interval
76 * @interval: new interval
77 *
78 * returns 0 on success, <0 on failures
79 *
80 * wdrtas_set_interval sets the watchdog keepalive interval by calling the
81 * RTAS function set-indicator (surveillance). The unit of interval is
82 * seconds.
83 */
84
wdrtas_set_interval(int interval)85 static int wdrtas_set_interval(int interval)
86 {
87 long result;
88 static int print_msg = 10;
89
90 /* rtas uses minutes */
91 interval = (interval + 59) / 60;
92
93 result = rtas_call(wdrtas_token_set_indicator, 3, 1, NULL,
94 WDRTAS_SURVEILLANCE_IND, 0, interval);
95 if (result < 0 && print_msg) {
96 printk(KERN_ERR "wdrtas: setting the watchdog to %i "
97 "timeout failed: %li\n", interval, result);
98 print_msg--;
99 }
100
101 return result;
102 }
103
104 #define WDRTAS_SP_SPI_LEN 4
105
106 /**
107 * wdrtas_get_interval - returns the current watchdog interval
108 * @fallback_value: value (in seconds) to use, if the RTAS call fails
109 *
110 * returns the interval
111 *
112 * wdrtas_get_interval returns the current watchdog keepalive interval
113 * as reported by the RTAS function ibm,get-system-parameter. The unit
114 * of the return value is seconds.
115 */
wdrtas_get_interval(int fallback_value)116 static int wdrtas_get_interval(int fallback_value)
117 {
118 long result;
119 char value[WDRTAS_SP_SPI_LEN];
120
121 spin_lock(&rtas_data_buf_lock);
122 memset(rtas_data_buf, 0, WDRTAS_SP_SPI_LEN);
123 result = rtas_call(wdrtas_token_get_sp, 3, 1, NULL,
124 WDRTAS_SP_SPI, __pa(rtas_data_buf),
125 WDRTAS_SP_SPI_LEN);
126
127 memcpy(value, rtas_data_buf, WDRTAS_SP_SPI_LEN);
128 spin_unlock(&rtas_data_buf_lock);
129
130 if (value[0] != 0 || value[1] != 2 || value[3] != 0 || result < 0) {
131 printk(KERN_WARNING "wdrtas: could not get sp_spi watchdog "
132 "timeout (%li). Continuing\n", result);
133 return fallback_value;
134 }
135
136 /* rtas uses minutes */
137 return ((int)value[2]) * 60;
138 }
139
140 /**
141 * wdrtas_timer_start - starts watchdog
142 *
143 * wdrtas_timer_start starts the watchdog by calling the RTAS function
144 * set-interval (surveillance)
145 */
wdrtas_timer_start(void)146 static void wdrtas_timer_start(void)
147 {
148 wdrtas_set_interval(wdrtas_interval);
149 }
150
151 /**
152 * wdrtas_timer_stop - stops watchdog
153 *
154 * wdrtas_timer_stop stops the watchdog timer by calling the RTAS function
155 * set-interval (surveillance)
156 */
wdrtas_timer_stop(void)157 static void wdrtas_timer_stop(void)
158 {
159 wdrtas_set_interval(0);
160 }
161
162 /**
163 * wdrtas_log_scanned_event - logs an event we received during keepalive
164 *
165 * wdrtas_log_scanned_event prints a message to the log buffer dumping
166 * the results of the last event-scan call
167 */
wdrtas_log_scanned_event(void)168 static void wdrtas_log_scanned_event(void)
169 {
170 int i;
171
172 for (i = 0; i < WDRTAS_LOGBUFFER_LEN; i += 16)
173 printk(KERN_INFO "wdrtas: dumping event (line %i/%i), data = "
174 "%02x %02x %02x %02x %02x %02x %02x %02x "
175 "%02x %02x %02x %02x %02x %02x %02x %02x\n",
176 (i / 16) + 1, (WDRTAS_LOGBUFFER_LEN / 16),
177 wdrtas_logbuffer[i + 0], wdrtas_logbuffer[i + 1],
178 wdrtas_logbuffer[i + 2], wdrtas_logbuffer[i + 3],
179 wdrtas_logbuffer[i + 4], wdrtas_logbuffer[i + 5],
180 wdrtas_logbuffer[i + 6], wdrtas_logbuffer[i + 7],
181 wdrtas_logbuffer[i + 8], wdrtas_logbuffer[i + 9],
182 wdrtas_logbuffer[i + 10], wdrtas_logbuffer[i + 11],
183 wdrtas_logbuffer[i + 12], wdrtas_logbuffer[i + 13],
184 wdrtas_logbuffer[i + 14], wdrtas_logbuffer[i + 15]);
185 }
186
187 /**
188 * wdrtas_timer_keepalive - resets watchdog timer to keep system alive
189 *
190 * wdrtas_timer_keepalive restarts the watchdog timer by calling the
191 * RTAS function event-scan and repeats these calls as long as there are
192 * events available. All events will be dumped.
193 */
wdrtas_timer_keepalive(void)194 static void wdrtas_timer_keepalive(void)
195 {
196 long result;
197
198 do {
199 result = rtas_call(wdrtas_token_event_scan, 4, 1, NULL,
200 RTAS_EVENT_SCAN_ALL_EVENTS, 0,
201 (void *)__pa(wdrtas_logbuffer),
202 WDRTAS_LOGBUFFER_LEN);
203 if (result < 0)
204 printk(KERN_ERR "wdrtas: event-scan failed: %li\n",
205 result);
206 if (result == 0)
207 wdrtas_log_scanned_event();
208 } while (result == 0);
209 }
210
211 /**
212 * wdrtas_get_temperature - returns current temperature
213 *
214 * returns temperature or <0 on failures
215 *
216 * wdrtas_get_temperature returns the current temperature in Fahrenheit. It
217 * uses the RTAS call get-sensor-state, token 3 to do so
218 */
wdrtas_get_temperature(void)219 static int wdrtas_get_temperature(void)
220 {
221 int result;
222 int temperature = 0;
223
224 result = rtas_get_sensor(WDRTAS_THERMAL_SENSOR, 0, &temperature);
225
226 if (result < 0)
227 printk(KERN_WARNING "wdrtas: reading the thermal sensor "
228 "failed: %i\n", result);
229 else
230 temperature = ((temperature * 9) / 5) + 32; /* fahrenheit */
231
232 return temperature;
233 }
234
235 /**
236 * wdrtas_get_status - returns the status of the watchdog
237 *
238 * returns a bitmask of defines WDIOF_... as defined in
239 * include/linux/watchdog.h
240 */
wdrtas_get_status(void)241 static int wdrtas_get_status(void)
242 {
243 return 0; /* TODO */
244 }
245
246 /**
247 * wdrtas_get_boot_status - returns the reason for the last boot
248 *
249 * returns a bitmask of defines WDIOF_... as defined in
250 * include/linux/watchdog.h, indicating why the watchdog rebooted the system
251 */
wdrtas_get_boot_status(void)252 static int wdrtas_get_boot_status(void)
253 {
254 return 0; /* TODO */
255 }
256
257 /*** watchdog API and operations stuff */
258
259 /* wdrtas_write - called when watchdog device is written to
260 * @file: file structure
261 * @buf: user buffer with data
262 * @len: amount to data written
263 * @ppos: position in file
264 *
265 * returns the number of successfully processed characters, which is always
266 * the number of bytes passed to this function
267 *
268 * wdrtas_write processes all the data given to it and looks for the magic
269 * character 'V'. This character allows the watchdog device to be closed
270 * properly.
271 */
wdrtas_write(struct file * file,const char __user * buf,size_t len,loff_t * ppos)272 static ssize_t wdrtas_write(struct file *file, const char __user *buf,
273 size_t len, loff_t *ppos)
274 {
275 int i;
276 char c;
277
278 if (!len)
279 goto out;
280
281 if (!wdrtas_nowayout) {
282 wdrtas_expect_close = 0;
283 /* look for 'V' */
284 for (i = 0; i < len; i++) {
285 if (get_user(c, buf + i))
286 return -EFAULT;
287 /* allow to close device */
288 if (c == 'V')
289 wdrtas_expect_close = WDRTAS_MAGIC_CHAR;
290 }
291 }
292
293 wdrtas_timer_keepalive();
294
295 out:
296 return len;
297 }
298
299 /**
300 * wdrtas_ioctl - ioctl function for the watchdog device
301 * @file: file structure
302 * @cmd: command for ioctl
303 * @arg: argument pointer
304 *
305 * returns 0 on success, <0 on failure
306 *
307 * wdrtas_ioctl implements the watchdog API ioctls
308 */
309
wdrtas_ioctl(struct file * file,unsigned int cmd,unsigned long arg)310 static long wdrtas_ioctl(struct file *file, unsigned int cmd,
311 unsigned long arg)
312 {
313 int __user *argp = (void __user *)arg;
314 int i;
315 static const struct watchdog_info wdinfo = {
316 .options = WDRTAS_SUPPORTED_MASK,
317 .firmware_version = 0,
318 .identity = "wdrtas",
319 };
320
321 switch (cmd) {
322 case WDIOC_GETSUPPORT:
323 if (copy_to_user(argp, &wdinfo, sizeof(wdinfo)))
324 return -EFAULT;
325 return 0;
326
327 case WDIOC_GETSTATUS:
328 i = wdrtas_get_status();
329 return put_user(i, argp);
330
331 case WDIOC_GETBOOTSTATUS:
332 i = wdrtas_get_boot_status();
333 return put_user(i, argp);
334
335 case WDIOC_GETTEMP:
336 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE)
337 return -EOPNOTSUPP;
338
339 i = wdrtas_get_temperature();
340 return put_user(i, argp);
341
342 case WDIOC_SETOPTIONS:
343 if (get_user(i, argp))
344 return -EFAULT;
345 if (i & WDIOS_DISABLECARD)
346 wdrtas_timer_stop();
347 if (i & WDIOS_ENABLECARD) {
348 wdrtas_timer_keepalive();
349 wdrtas_timer_start();
350 }
351 /* not implemented. Done by H8
352 if (i & WDIOS_TEMPPANIC) {
353 } */
354 return 0;
355
356 case WDIOC_KEEPALIVE:
357 wdrtas_timer_keepalive();
358 return 0;
359
360 case WDIOC_SETTIMEOUT:
361 if (get_user(i, argp))
362 return -EFAULT;
363
364 if (wdrtas_set_interval(i))
365 return -EINVAL;
366
367 wdrtas_timer_keepalive();
368
369 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
370 wdrtas_interval = i;
371 else
372 wdrtas_interval = wdrtas_get_interval(i);
373 /* fallthrough */
374
375 case WDIOC_GETTIMEOUT:
376 return put_user(wdrtas_interval, argp);
377
378 default:
379 return -ENOTTY;
380 }
381 }
382
383 /**
384 * wdrtas_open - open function of watchdog device
385 * @inode: inode structure
386 * @file: file structure
387 *
388 * returns 0 on success, -EBUSY if the file has been opened already, <0 on
389 * other failures
390 *
391 * function called when watchdog device is opened
392 */
wdrtas_open(struct inode * inode,struct file * file)393 static int wdrtas_open(struct inode *inode, struct file *file)
394 {
395 /* only open once */
396 if (atomic_inc_return(&wdrtas_miscdev_open) > 1) {
397 atomic_dec(&wdrtas_miscdev_open);
398 return -EBUSY;
399 }
400
401 wdrtas_timer_start();
402 wdrtas_timer_keepalive();
403
404 return nonseekable_open(inode, file);
405 }
406
407 /**
408 * wdrtas_close - close function of watchdog device
409 * @inode: inode structure
410 * @file: file structure
411 *
412 * returns 0 on success
413 *
414 * close function. Always succeeds
415 */
wdrtas_close(struct inode * inode,struct file * file)416 static int wdrtas_close(struct inode *inode, struct file *file)
417 {
418 /* only stop watchdog, if this was announced using 'V' before */
419 if (wdrtas_expect_close == WDRTAS_MAGIC_CHAR)
420 wdrtas_timer_stop();
421 else {
422 printk(KERN_WARNING "wdrtas: got unexpected close. Watchdog "
423 "not stopped.\n");
424 wdrtas_timer_keepalive();
425 }
426
427 wdrtas_expect_close = 0;
428 atomic_dec(&wdrtas_miscdev_open);
429 return 0;
430 }
431
432 /**
433 * wdrtas_temp_read - gives back the temperature in fahrenheit
434 * @file: file structure
435 * @buf: user buffer
436 * @count: number of bytes to be read
437 * @ppos: position in file
438 *
439 * returns always 1 or -EFAULT in case of user space copy failures, <0 on
440 * other failures
441 *
442 * wdrtas_temp_read gives the temperature to the users by copying this
443 * value as one byte into the user space buffer. The unit is Fahrenheit...
444 */
wdrtas_temp_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)445 static ssize_t wdrtas_temp_read(struct file *file, char __user *buf,
446 size_t count, loff_t *ppos)
447 {
448 int temperature = 0;
449
450 temperature = wdrtas_get_temperature();
451 if (temperature < 0)
452 return temperature;
453
454 if (copy_to_user(buf, &temperature, 1))
455 return -EFAULT;
456
457 return 1;
458 }
459
460 /**
461 * wdrtas_temp_open - open function of temperature device
462 * @inode: inode structure
463 * @file: file structure
464 *
465 * returns 0 on success, <0 on failure
466 *
467 * function called when temperature device is opened
468 */
wdrtas_temp_open(struct inode * inode,struct file * file)469 static int wdrtas_temp_open(struct inode *inode, struct file *file)
470 {
471 return nonseekable_open(inode, file);
472 }
473
474 /**
475 * wdrtas_temp_close - close function of temperature device
476 * @inode: inode structure
477 * @file: file structure
478 *
479 * returns 0 on success
480 *
481 * close function. Always succeeds
482 */
wdrtas_temp_close(struct inode * inode,struct file * file)483 static int wdrtas_temp_close(struct inode *inode, struct file *file)
484 {
485 return 0;
486 }
487
488 /**
489 * wdrtas_reboot - reboot notifier function
490 * @nb: notifier block structure
491 * @code: reboot code
492 * @ptr: unused
493 *
494 * returns NOTIFY_DONE
495 *
496 * wdrtas_reboot stops the watchdog in case of a reboot
497 */
wdrtas_reboot(struct notifier_block * this,unsigned long code,void * ptr)498 static int wdrtas_reboot(struct notifier_block *this,
499 unsigned long code, void *ptr)
500 {
501 if (code == SYS_DOWN || code == SYS_HALT)
502 wdrtas_timer_stop();
503
504 return NOTIFY_DONE;
505 }
506
507 /*** initialization stuff */
508
509 static const struct file_operations wdrtas_fops = {
510 .owner = THIS_MODULE,
511 .llseek = no_llseek,
512 .write = wdrtas_write,
513 .unlocked_ioctl = wdrtas_ioctl,
514 .open = wdrtas_open,
515 .release = wdrtas_close,
516 };
517
518 static struct miscdevice wdrtas_miscdev = {
519 .minor = WATCHDOG_MINOR,
520 .name = "watchdog",
521 .fops = &wdrtas_fops,
522 };
523
524 static const struct file_operations wdrtas_temp_fops = {
525 .owner = THIS_MODULE,
526 .llseek = no_llseek,
527 .read = wdrtas_temp_read,
528 .open = wdrtas_temp_open,
529 .release = wdrtas_temp_close,
530 };
531
532 static struct miscdevice wdrtas_tempdev = {
533 .minor = TEMP_MINOR,
534 .name = "temperature",
535 .fops = &wdrtas_temp_fops,
536 };
537
538 static struct notifier_block wdrtas_notifier = {
539 .notifier_call = wdrtas_reboot,
540 };
541
542 /**
543 * wdrtas_get_tokens - reads in RTAS tokens
544 *
545 * returns 0 on success, <0 on failure
546 *
547 * wdrtas_get_tokens reads in the tokens for the RTAS calls used in
548 * this watchdog driver. It tolerates, if "get-sensor-state" and
549 * "ibm,get-system-parameter" are not available.
550 */
wdrtas_get_tokens(void)551 static int wdrtas_get_tokens(void)
552 {
553 wdrtas_token_get_sensor_state = rtas_token("get-sensor-state");
554 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) {
555 printk(KERN_WARNING "wdrtas: couldn't get token for "
556 "get-sensor-state. Trying to continue without "
557 "temperature support.\n");
558 }
559
560 wdrtas_token_get_sp = rtas_token("ibm,get-system-parameter");
561 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) {
562 printk(KERN_WARNING "wdrtas: couldn't get token for "
563 "ibm,get-system-parameter. Trying to continue with "
564 "a default timeout value of %i seconds.\n",
565 WDRTAS_DEFAULT_INTERVAL);
566 }
567
568 wdrtas_token_set_indicator = rtas_token("set-indicator");
569 if (wdrtas_token_set_indicator == RTAS_UNKNOWN_SERVICE) {
570 printk(KERN_ERR "wdrtas: couldn't get token for "
571 "set-indicator. Terminating watchdog code.\n");
572 return -EIO;
573 }
574
575 wdrtas_token_event_scan = rtas_token("event-scan");
576 if (wdrtas_token_event_scan == RTAS_UNKNOWN_SERVICE) {
577 printk(KERN_ERR "wdrtas: couldn't get token for event-scan. "
578 "Terminating watchdog code.\n");
579 return -EIO;
580 }
581
582 return 0;
583 }
584
585 /**
586 * wdrtas_unregister_devs - unregisters the misc dev handlers
587 *
588 * wdrtas_register_devs unregisters the watchdog and temperature watchdog
589 * misc devs
590 */
wdrtas_unregister_devs(void)591 static void wdrtas_unregister_devs(void)
592 {
593 misc_deregister(&wdrtas_miscdev);
594 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE)
595 misc_deregister(&wdrtas_tempdev);
596 }
597
598 /**
599 * wdrtas_register_devs - registers the misc dev handlers
600 *
601 * returns 0 on success, <0 on failure
602 *
603 * wdrtas_register_devs registers the watchdog and temperature watchdog
604 * misc devs
605 */
wdrtas_register_devs(void)606 static int wdrtas_register_devs(void)
607 {
608 int result;
609
610 result = misc_register(&wdrtas_miscdev);
611 if (result) {
612 printk(KERN_ERR "wdrtas: couldn't register watchdog misc "
613 "device. Terminating watchdog code.\n");
614 return result;
615 }
616
617 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) {
618 result = misc_register(&wdrtas_tempdev);
619 if (result) {
620 printk(KERN_WARNING "wdrtas: couldn't register "
621 "watchdog temperature misc device. Continuing "
622 "without temperature support.\n");
623 wdrtas_token_get_sensor_state = RTAS_UNKNOWN_SERVICE;
624 }
625 }
626
627 return 0;
628 }
629
630 /**
631 * wdrtas_init - init function of the watchdog driver
632 *
633 * returns 0 on success, <0 on failure
634 *
635 * registers the file handlers and the reboot notifier
636 */
wdrtas_init(void)637 static int __init wdrtas_init(void)
638 {
639 if (wdrtas_get_tokens())
640 return -ENODEV;
641
642 if (wdrtas_register_devs())
643 return -ENODEV;
644
645 if (register_reboot_notifier(&wdrtas_notifier)) {
646 printk(KERN_ERR "wdrtas: could not register reboot notifier. "
647 "Terminating watchdog code.\n");
648 wdrtas_unregister_devs();
649 return -ENODEV;
650 }
651
652 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
653 wdrtas_interval = WDRTAS_DEFAULT_INTERVAL;
654 else
655 wdrtas_interval = wdrtas_get_interval(WDRTAS_DEFAULT_INTERVAL);
656
657 return 0;
658 }
659
660 /**
661 * wdrtas_exit - exit function of the watchdog driver
662 *
663 * unregisters the file handlers and the reboot notifier
664 */
wdrtas_exit(void)665 static void __exit wdrtas_exit(void)
666 {
667 if (!wdrtas_nowayout)
668 wdrtas_timer_stop();
669
670 wdrtas_unregister_devs();
671
672 unregister_reboot_notifier(&wdrtas_notifier);
673 }
674
675 module_init(wdrtas_init);
676 module_exit(wdrtas_exit);
677