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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
30
31 #include <linux/fs.h>
32 #include <linux/init.h>
33 #include <linux/kernel.h>
34 #include <linux/miscdevice.h>
35 #include <linux/module.h>
36 #include <linux/notifier.h>
37 #include <linux/reboot.h>
38 #include <linux/types.h>
39 #include <linux/watchdog.h>
40 #include <linux/uaccess.h>
41
42 #include <asm/rtas.h>
43
44 #define WDRTAS_MAGIC_CHAR 42
45 #define WDRTAS_SUPPORTED_MASK (WDIOF_SETTIMEOUT | \
46 WDIOF_MAGICCLOSE)
47
48 MODULE_AUTHOR("Utz Bacher <utz.bacher@de.ibm.com>");
49 MODULE_DESCRIPTION("RTAS watchdog driver");
50 MODULE_LICENSE("GPL");
51
52 static bool 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 pr_err("setting the watchdog to %i timeout failed: %li\n",
97 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 pr_warn("could not get sp_spi watchdog timeout (%li). Continuing\n",
132 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_timer_keepalive - resets watchdog timer to keep system alive
164 *
165 * wdrtas_timer_keepalive restarts the watchdog timer by calling the
166 * RTAS function event-scan and repeats these calls as long as there are
167 * events available. All events will be dumped.
168 */
wdrtas_timer_keepalive(void)169 static void wdrtas_timer_keepalive(void)
170 {
171 long result;
172
173 do {
174 result = rtas_call(wdrtas_token_event_scan, 4, 1, NULL,
175 RTAS_EVENT_SCAN_ALL_EVENTS, 0,
176 (void *)__pa(wdrtas_logbuffer),
177 WDRTAS_LOGBUFFER_LEN);
178 if (result < 0)
179 pr_err("event-scan failed: %li\n", result);
180 if (result == 0)
181 print_hex_dump(KERN_INFO, "dumping event, data: ",
182 DUMP_PREFIX_OFFSET, 16, 1,
183 wdrtas_logbuffer, WDRTAS_LOGBUFFER_LEN, false);
184 } while (result == 0);
185 }
186
187 /**
188 * wdrtas_get_temperature - returns current temperature
189 *
190 * returns temperature or <0 on failures
191 *
192 * wdrtas_get_temperature returns the current temperature in Fahrenheit. It
193 * uses the RTAS call get-sensor-state, token 3 to do so
194 */
wdrtas_get_temperature(void)195 static int wdrtas_get_temperature(void)
196 {
197 int result;
198 int temperature = 0;
199
200 result = rtas_get_sensor(WDRTAS_THERMAL_SENSOR, 0, &temperature);
201
202 if (result < 0)
203 pr_warn("reading the thermal sensor failed: %i\n", result);
204 else
205 temperature = ((temperature * 9) / 5) + 32; /* fahrenheit */
206
207 return temperature;
208 }
209
210 /**
211 * wdrtas_get_status - returns the status of the watchdog
212 *
213 * returns a bitmask of defines WDIOF_... as defined in
214 * include/linux/watchdog.h
215 */
wdrtas_get_status(void)216 static int wdrtas_get_status(void)
217 {
218 return 0; /* TODO */
219 }
220
221 /**
222 * wdrtas_get_boot_status - returns the reason for the last boot
223 *
224 * returns a bitmask of defines WDIOF_... as defined in
225 * include/linux/watchdog.h, indicating why the watchdog rebooted the system
226 */
wdrtas_get_boot_status(void)227 static int wdrtas_get_boot_status(void)
228 {
229 return 0; /* TODO */
230 }
231
232 /*** watchdog API and operations stuff */
233
234 /* wdrtas_write - called when watchdog device is written to
235 * @file: file structure
236 * @buf: user buffer with data
237 * @len: amount to data written
238 * @ppos: position in file
239 *
240 * returns the number of successfully processed characters, which is always
241 * the number of bytes passed to this function
242 *
243 * wdrtas_write processes all the data given to it and looks for the magic
244 * character 'V'. This character allows the watchdog device to be closed
245 * properly.
246 */
wdrtas_write(struct file * file,const char __user * buf,size_t len,loff_t * ppos)247 static ssize_t wdrtas_write(struct file *file, const char __user *buf,
248 size_t len, loff_t *ppos)
249 {
250 int i;
251 char c;
252
253 if (!len)
254 goto out;
255
256 if (!wdrtas_nowayout) {
257 wdrtas_expect_close = 0;
258 /* look for 'V' */
259 for (i = 0; i < len; i++) {
260 if (get_user(c, buf + i))
261 return -EFAULT;
262 /* allow to close device */
263 if (c == 'V')
264 wdrtas_expect_close = WDRTAS_MAGIC_CHAR;
265 }
266 }
267
268 wdrtas_timer_keepalive();
269
270 out:
271 return len;
272 }
273
274 /**
275 * wdrtas_ioctl - ioctl function for the watchdog device
276 * @file: file structure
277 * @cmd: command for ioctl
278 * @arg: argument pointer
279 *
280 * returns 0 on success, <0 on failure
281 *
282 * wdrtas_ioctl implements the watchdog API ioctls
283 */
284
wdrtas_ioctl(struct file * file,unsigned int cmd,unsigned long arg)285 static long wdrtas_ioctl(struct file *file, unsigned int cmd,
286 unsigned long arg)
287 {
288 int __user *argp = (void __user *)arg;
289 int i;
290 static const struct watchdog_info wdinfo = {
291 .options = WDRTAS_SUPPORTED_MASK,
292 .firmware_version = 0,
293 .identity = "wdrtas",
294 };
295
296 switch (cmd) {
297 case WDIOC_GETSUPPORT:
298 if (copy_to_user(argp, &wdinfo, sizeof(wdinfo)))
299 return -EFAULT;
300 return 0;
301
302 case WDIOC_GETSTATUS:
303 i = wdrtas_get_status();
304 return put_user(i, argp);
305
306 case WDIOC_GETBOOTSTATUS:
307 i = wdrtas_get_boot_status();
308 return put_user(i, argp);
309
310 case WDIOC_GETTEMP:
311 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE)
312 return -EOPNOTSUPP;
313
314 i = wdrtas_get_temperature();
315 return put_user(i, argp);
316
317 case WDIOC_SETOPTIONS:
318 if (get_user(i, argp))
319 return -EFAULT;
320 if (i & WDIOS_DISABLECARD)
321 wdrtas_timer_stop();
322 if (i & WDIOS_ENABLECARD) {
323 wdrtas_timer_keepalive();
324 wdrtas_timer_start();
325 }
326 /* not implemented. Done by H8
327 if (i & WDIOS_TEMPPANIC) {
328 } */
329 return 0;
330
331 case WDIOC_KEEPALIVE:
332 wdrtas_timer_keepalive();
333 return 0;
334
335 case WDIOC_SETTIMEOUT:
336 if (get_user(i, argp))
337 return -EFAULT;
338
339 if (wdrtas_set_interval(i))
340 return -EINVAL;
341
342 wdrtas_timer_keepalive();
343
344 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
345 wdrtas_interval = i;
346 else
347 wdrtas_interval = wdrtas_get_interval(i);
348 /* fallthrough */
349
350 case WDIOC_GETTIMEOUT:
351 return put_user(wdrtas_interval, argp);
352
353 default:
354 return -ENOTTY;
355 }
356 }
357
358 /**
359 * wdrtas_open - open function of watchdog device
360 * @inode: inode structure
361 * @file: file structure
362 *
363 * returns 0 on success, -EBUSY if the file has been opened already, <0 on
364 * other failures
365 *
366 * function called when watchdog device is opened
367 */
wdrtas_open(struct inode * inode,struct file * file)368 static int wdrtas_open(struct inode *inode, struct file *file)
369 {
370 /* only open once */
371 if (atomic_inc_return(&wdrtas_miscdev_open) > 1) {
372 atomic_dec(&wdrtas_miscdev_open);
373 return -EBUSY;
374 }
375
376 wdrtas_timer_start();
377 wdrtas_timer_keepalive();
378
379 return nonseekable_open(inode, file);
380 }
381
382 /**
383 * wdrtas_close - close function of watchdog device
384 * @inode: inode structure
385 * @file: file structure
386 *
387 * returns 0 on success
388 *
389 * close function. Always succeeds
390 */
wdrtas_close(struct inode * inode,struct file * file)391 static int wdrtas_close(struct inode *inode, struct file *file)
392 {
393 /* only stop watchdog, if this was announced using 'V' before */
394 if (wdrtas_expect_close == WDRTAS_MAGIC_CHAR)
395 wdrtas_timer_stop();
396 else {
397 pr_warn("got unexpected close. Watchdog not stopped.\n");
398 wdrtas_timer_keepalive();
399 }
400
401 wdrtas_expect_close = 0;
402 atomic_dec(&wdrtas_miscdev_open);
403 return 0;
404 }
405
406 /**
407 * wdrtas_temp_read - gives back the temperature in fahrenheit
408 * @file: file structure
409 * @buf: user buffer
410 * @count: number of bytes to be read
411 * @ppos: position in file
412 *
413 * returns always 1 or -EFAULT in case of user space copy failures, <0 on
414 * other failures
415 *
416 * wdrtas_temp_read gives the temperature to the users by copying this
417 * value as one byte into the user space buffer. The unit is Fahrenheit...
418 */
wdrtas_temp_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)419 static ssize_t wdrtas_temp_read(struct file *file, char __user *buf,
420 size_t count, loff_t *ppos)
421 {
422 int temperature = 0;
423
424 temperature = wdrtas_get_temperature();
425 if (temperature < 0)
426 return temperature;
427
428 if (copy_to_user(buf, &temperature, 1))
429 return -EFAULT;
430
431 return 1;
432 }
433
434 /**
435 * wdrtas_temp_open - open function of temperature device
436 * @inode: inode structure
437 * @file: file structure
438 *
439 * returns 0 on success, <0 on failure
440 *
441 * function called when temperature device is opened
442 */
wdrtas_temp_open(struct inode * inode,struct file * file)443 static int wdrtas_temp_open(struct inode *inode, struct file *file)
444 {
445 return nonseekable_open(inode, file);
446 }
447
448 /**
449 * wdrtas_temp_close - close function of temperature device
450 * @inode: inode structure
451 * @file: file structure
452 *
453 * returns 0 on success
454 *
455 * close function. Always succeeds
456 */
wdrtas_temp_close(struct inode * inode,struct file * file)457 static int wdrtas_temp_close(struct inode *inode, struct file *file)
458 {
459 return 0;
460 }
461
462 /**
463 * wdrtas_reboot - reboot notifier function
464 * @nb: notifier block structure
465 * @code: reboot code
466 * @ptr: unused
467 *
468 * returns NOTIFY_DONE
469 *
470 * wdrtas_reboot stops the watchdog in case of a reboot
471 */
wdrtas_reboot(struct notifier_block * this,unsigned long code,void * ptr)472 static int wdrtas_reboot(struct notifier_block *this,
473 unsigned long code, void *ptr)
474 {
475 if (code == SYS_DOWN || code == SYS_HALT)
476 wdrtas_timer_stop();
477
478 return NOTIFY_DONE;
479 }
480
481 /*** initialization stuff */
482
483 static const struct file_operations wdrtas_fops = {
484 .owner = THIS_MODULE,
485 .llseek = no_llseek,
486 .write = wdrtas_write,
487 .unlocked_ioctl = wdrtas_ioctl,
488 .open = wdrtas_open,
489 .release = wdrtas_close,
490 };
491
492 static struct miscdevice wdrtas_miscdev = {
493 .minor = WATCHDOG_MINOR,
494 .name = "watchdog",
495 .fops = &wdrtas_fops,
496 };
497
498 static const struct file_operations wdrtas_temp_fops = {
499 .owner = THIS_MODULE,
500 .llseek = no_llseek,
501 .read = wdrtas_temp_read,
502 .open = wdrtas_temp_open,
503 .release = wdrtas_temp_close,
504 };
505
506 static struct miscdevice wdrtas_tempdev = {
507 .minor = TEMP_MINOR,
508 .name = "temperature",
509 .fops = &wdrtas_temp_fops,
510 };
511
512 static struct notifier_block wdrtas_notifier = {
513 .notifier_call = wdrtas_reboot,
514 };
515
516 /**
517 * wdrtas_get_tokens - reads in RTAS tokens
518 *
519 * returns 0 on success, <0 on failure
520 *
521 * wdrtas_get_tokens reads in the tokens for the RTAS calls used in
522 * this watchdog driver. It tolerates, if "get-sensor-state" and
523 * "ibm,get-system-parameter" are not available.
524 */
wdrtas_get_tokens(void)525 static int wdrtas_get_tokens(void)
526 {
527 wdrtas_token_get_sensor_state = rtas_token("get-sensor-state");
528 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) {
529 pr_warn("couldn't get token for get-sensor-state. Trying to continue without temperature support.\n");
530 }
531
532 wdrtas_token_get_sp = rtas_token("ibm,get-system-parameter");
533 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) {
534 pr_warn("couldn't get token for ibm,get-system-parameter. Trying to continue with a default timeout value of %i seconds.\n",
535 WDRTAS_DEFAULT_INTERVAL);
536 }
537
538 wdrtas_token_set_indicator = rtas_token("set-indicator");
539 if (wdrtas_token_set_indicator == RTAS_UNKNOWN_SERVICE) {
540 pr_err("couldn't get token for set-indicator. Terminating watchdog code.\n");
541 return -EIO;
542 }
543
544 wdrtas_token_event_scan = rtas_token("event-scan");
545 if (wdrtas_token_event_scan == RTAS_UNKNOWN_SERVICE) {
546 pr_err("couldn't get token for event-scan. Terminating watchdog code.\n");
547 return -EIO;
548 }
549
550 return 0;
551 }
552
553 /**
554 * wdrtas_unregister_devs - unregisters the misc dev handlers
555 *
556 * wdrtas_register_devs unregisters the watchdog and temperature watchdog
557 * misc devs
558 */
wdrtas_unregister_devs(void)559 static void wdrtas_unregister_devs(void)
560 {
561 misc_deregister(&wdrtas_miscdev);
562 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE)
563 misc_deregister(&wdrtas_tempdev);
564 }
565
566 /**
567 * wdrtas_register_devs - registers the misc dev handlers
568 *
569 * returns 0 on success, <0 on failure
570 *
571 * wdrtas_register_devs registers the watchdog and temperature watchdog
572 * misc devs
573 */
wdrtas_register_devs(void)574 static int wdrtas_register_devs(void)
575 {
576 int result;
577
578 result = misc_register(&wdrtas_miscdev);
579 if (result) {
580 pr_err("couldn't register watchdog misc device. Terminating watchdog code.\n");
581 return result;
582 }
583
584 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) {
585 result = misc_register(&wdrtas_tempdev);
586 if (result) {
587 pr_warn("couldn't register watchdog temperature misc device. Continuing without temperature support.\n");
588 wdrtas_token_get_sensor_state = RTAS_UNKNOWN_SERVICE;
589 }
590 }
591
592 return 0;
593 }
594
595 /**
596 * wdrtas_init - init function of the watchdog driver
597 *
598 * returns 0 on success, <0 on failure
599 *
600 * registers the file handlers and the reboot notifier
601 */
wdrtas_init(void)602 static int __init wdrtas_init(void)
603 {
604 if (wdrtas_get_tokens())
605 return -ENODEV;
606
607 if (wdrtas_register_devs())
608 return -ENODEV;
609
610 if (register_reboot_notifier(&wdrtas_notifier)) {
611 pr_err("could not register reboot notifier. Terminating watchdog code.\n");
612 wdrtas_unregister_devs();
613 return -ENODEV;
614 }
615
616 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
617 wdrtas_interval = WDRTAS_DEFAULT_INTERVAL;
618 else
619 wdrtas_interval = wdrtas_get_interval(WDRTAS_DEFAULT_INTERVAL);
620
621 return 0;
622 }
623
624 /**
625 * wdrtas_exit - exit function of the watchdog driver
626 *
627 * unregisters the file handlers and the reboot notifier
628 */
wdrtas_exit(void)629 static void __exit wdrtas_exit(void)
630 {
631 if (!wdrtas_nowayout)
632 wdrtas_timer_stop();
633
634 wdrtas_unregister_devs();
635
636 unregister_reboot_notifier(&wdrtas_notifier);
637 }
638
639 module_init(wdrtas_init);
640 module_exit(wdrtas_exit);
641
