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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * FIXME: add wdrtas_get_status and wdrtas_get_boot_status as soon as
4 * RTAS calls are available
5 */
6
7/*
8 * RTAS watchdog driver
9 *
10 * (C) Copyright IBM Corp. 2005
11 * device driver to exploit watchdog RTAS functions
12 *
13 * Authors : Utz Bacher <utz.bacher@de.ibm.com>
14 */
15
16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18#include <linux/fs.h>
19#include <linux/init.h>
20#include <linux/kernel.h>
21#include <linux/miscdevice.h>
22#include <linux/module.h>
23#include <linux/notifier.h>
24#include <linux/reboot.h>
25#include <linux/types.h>
26#include <linux/watchdog.h>
27#include <linux/uaccess.h>
28
29#include <asm/rtas.h>
30
31#define WDRTAS_MAGIC_CHAR 42
32#define WDRTAS_SUPPORTED_MASK (WDIOF_SETTIMEOUT | \
33 WDIOF_MAGICCLOSE)
34
35MODULE_AUTHOR("Utz Bacher <utz.bacher@de.ibm.com>");
36MODULE_DESCRIPTION("RTAS watchdog driver");
37MODULE_LICENSE("GPL");
38
39static bool wdrtas_nowayout = WATCHDOG_NOWAYOUT;
40static atomic_t wdrtas_miscdev_open = ATOMIC_INIT(0);
41static char wdrtas_expect_close;
42
43static int wdrtas_interval;
44
45#define WDRTAS_THERMAL_SENSOR 3
46static int wdrtas_token_get_sensor_state;
47#define WDRTAS_SURVEILLANCE_IND 9000
48static int wdrtas_token_set_indicator;
49#define WDRTAS_SP_SPI 28
50static int wdrtas_token_get_sp;
51static int wdrtas_token_event_scan;
52
53#define WDRTAS_DEFAULT_INTERVAL 300
54
55#define WDRTAS_LOGBUFFER_LEN 128
56static char wdrtas_logbuffer[WDRTAS_LOGBUFFER_LEN];
57
58
59/*** watchdog access functions */
60
61/**
62 * wdrtas_set_interval - sets the watchdog interval
63 * @interval: new interval
64 *
65 * returns 0 on success, <0 on failures
66 *
67 * wdrtas_set_interval sets the watchdog keepalive interval by calling the
68 * RTAS function set-indicator (surveillance). The unit of interval is
69 * seconds.
70 */
71
72static int wdrtas_set_interval(int interval)
73{
74 long result;
75 static int print_msg = 10;
76
77 /* rtas uses minutes */
78 interval = (interval + 59) / 60;
79
80 result = rtas_call(wdrtas_token_set_indicator, 3, 1, NULL,
81 WDRTAS_SURVEILLANCE_IND, 0, interval);
82 if (result < 0 && print_msg) {
83 pr_err("setting the watchdog to %i timeout failed: %li\n",
84 interval, result);
85 print_msg--;
86 }
87
88 return result;
89}
90
91#define WDRTAS_SP_SPI_LEN 4
92
93/**
94 * wdrtas_get_interval - returns the current watchdog interval
95 * @fallback_value: value (in seconds) to use, if the RTAS call fails
96 *
97 * returns the interval
98 *
99 * wdrtas_get_interval returns the current watchdog keepalive interval
100 * as reported by the RTAS function ibm,get-system-parameter. The unit
101 * of the return value is seconds.
102 */
103static int wdrtas_get_interval(int fallback_value)
104{
105 long result;
106 char value[WDRTAS_SP_SPI_LEN];
107
108 spin_lock(&rtas_data_buf_lock);
109 memset(rtas_data_buf, 0, WDRTAS_SP_SPI_LEN);
110 result = rtas_call(wdrtas_token_get_sp, 3, 1, NULL,
111 WDRTAS_SP_SPI, __pa(rtas_data_buf),
112 WDRTAS_SP_SPI_LEN);
113
114 memcpy(value, rtas_data_buf, WDRTAS_SP_SPI_LEN);
115 spin_unlock(&rtas_data_buf_lock);
116
117 if (value[0] != 0 || value[1] != 2 || value[3] != 0 || result < 0) {
118 pr_warn("could not get sp_spi watchdog timeout (%li). Continuing\n",
119 result);
120 return fallback_value;
121 }
122
123 /* rtas uses minutes */
124 return ((int)value[2]) * 60;
125}
126
127/**
128 * wdrtas_timer_start - starts watchdog
129 *
130 * wdrtas_timer_start starts the watchdog by calling the RTAS function
131 * set-interval (surveillance)
132 */
133static void wdrtas_timer_start(void)
134{
135 wdrtas_set_interval(wdrtas_interval);
136}
137
138/**
139 * wdrtas_timer_stop - stops watchdog
140 *
141 * wdrtas_timer_stop stops the watchdog timer by calling the RTAS function
142 * set-interval (surveillance)
143 */
144static void wdrtas_timer_stop(void)
145{
146 wdrtas_set_interval(0);
147}
148
149/**
150 * wdrtas_timer_keepalive - resets watchdog timer to keep system alive
151 *
152 * wdrtas_timer_keepalive restarts the watchdog timer by calling the
153 * RTAS function event-scan and repeats these calls as long as there are
154 * events available. All events will be dumped.
155 */
156static void wdrtas_timer_keepalive(void)
157{
158 long result;
159
160 do {
161 result = rtas_call(wdrtas_token_event_scan, 4, 1, NULL,
162 RTAS_EVENT_SCAN_ALL_EVENTS, 0,
163 (void *)__pa(wdrtas_logbuffer),
164 WDRTAS_LOGBUFFER_LEN);
165 if (result < 0)
166 pr_err("event-scan failed: %li\n", result);
167 if (result == 0)
168 print_hex_dump(KERN_INFO, "dumping event, data: ",
169 DUMP_PREFIX_OFFSET, 16, 1,
170 wdrtas_logbuffer, WDRTAS_LOGBUFFER_LEN, false);
171 } while (result == 0);
172}
173
174/**
175 * wdrtas_get_temperature - returns current temperature
176 *
177 * returns temperature or <0 on failures
178 *
179 * wdrtas_get_temperature returns the current temperature in Fahrenheit. It
180 * uses the RTAS call get-sensor-state, token 3 to do so
181 */
182static int wdrtas_get_temperature(void)
183{
184 int result;
185 int temperature = 0;
186
187 result = rtas_get_sensor(WDRTAS_THERMAL_SENSOR, 0, &temperature);
188
189 if (result < 0)
190 pr_warn("reading the thermal sensor failed: %i\n", result);
191 else
192 temperature = ((temperature * 9) / 5) + 32; /* fahrenheit */
193
194 return temperature;
195}
196
197/**
198 * wdrtas_get_status - returns the status of the watchdog
199 *
200 * returns a bitmask of defines WDIOF_... as defined in
201 * include/linux/watchdog.h
202 */
203static int wdrtas_get_status(void)
204{
205 return 0; /* TODO */
206}
207
208/**
209 * wdrtas_get_boot_status - returns the reason for the last boot
210 *
211 * returns a bitmask of defines WDIOF_... as defined in
212 * include/linux/watchdog.h, indicating why the watchdog rebooted the system
213 */
214static int wdrtas_get_boot_status(void)
215{
216 return 0; /* TODO */
217}
218
219/*** watchdog API and operations stuff */
220
221/* wdrtas_write - called when watchdog device is written to
222 * @file: file structure
223 * @buf: user buffer with data
224 * @len: amount to data written
225 * @ppos: position in file
226 *
227 * returns the number of successfully processed characters, which is always
228 * the number of bytes passed to this function
229 *
230 * wdrtas_write processes all the data given to it and looks for the magic
231 * character 'V'. This character allows the watchdog device to be closed
232 * properly.
233 */
234static ssize_t wdrtas_write(struct file *file, const char __user *buf,
235 size_t len, loff_t *ppos)
236{
237 int i;
238 char c;
239
240 if (!len)
241 goto out;
242
243 if (!wdrtas_nowayout) {
244 wdrtas_expect_close = 0;
245 /* look for 'V' */
246 for (i = 0; i < len; i++) {
247 if (get_user(c, buf + i))
248 return -EFAULT;
249 /* allow to close device */
250 if (c == 'V')
251 wdrtas_expect_close = WDRTAS_MAGIC_CHAR;
252 }
253 }
254
255 wdrtas_timer_keepalive();
256
257out:
258 return len;
259}
260
261/**
262 * wdrtas_ioctl - ioctl function for the watchdog device
263 * @file: file structure
264 * @cmd: command for ioctl
265 * @arg: argument pointer
266 *
267 * returns 0 on success, <0 on failure
268 *
269 * wdrtas_ioctl implements the watchdog API ioctls
270 */
271
272static long wdrtas_ioctl(struct file *file, unsigned int cmd,
273 unsigned long arg)
274{
275 int __user *argp = (void __user *)arg;
276 int i;
277 static const struct watchdog_info wdinfo = {
278 .options = WDRTAS_SUPPORTED_MASK,
279 .firmware_version = 0,
280 .identity = "wdrtas",
281 };
282
283 switch (cmd) {
284 case WDIOC_GETSUPPORT:
285 if (copy_to_user(argp, &wdinfo, sizeof(wdinfo)))
286 return -EFAULT;
287 return 0;
288
289 case WDIOC_GETSTATUS:
290 i = wdrtas_get_status();
291 return put_user(i, argp);
292
293 case WDIOC_GETBOOTSTATUS:
294 i = wdrtas_get_boot_status();
295 return put_user(i, argp);
296
297 case WDIOC_GETTEMP:
298 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE)
299 return -EOPNOTSUPP;
300
301 i = wdrtas_get_temperature();
302 return put_user(i, argp);
303
304 case WDIOC_SETOPTIONS:
305 if (get_user(i, argp))
306 return -EFAULT;
307 if (i & WDIOS_DISABLECARD)
308 wdrtas_timer_stop();
309 if (i & WDIOS_ENABLECARD) {
310 wdrtas_timer_keepalive();
311 wdrtas_timer_start();
312 }
313 /* not implemented. Done by H8
314 if (i & WDIOS_TEMPPANIC) {
315 } */
316 return 0;
317
318 case WDIOC_KEEPALIVE:
319 wdrtas_timer_keepalive();
320 return 0;
321
322 case WDIOC_SETTIMEOUT:
323 if (get_user(i, argp))
324 return -EFAULT;
325
326 if (wdrtas_set_interval(i))
327 return -EINVAL;
328
329 wdrtas_timer_keepalive();
330
331 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
332 wdrtas_interval = i;
333 else
334 wdrtas_interval = wdrtas_get_interval(i);
335 fallthrough;
336
337 case WDIOC_GETTIMEOUT:
338 return put_user(wdrtas_interval, argp);
339
340 default:
341 return -ENOTTY;
342 }
343}
344
345/**
346 * wdrtas_open - open function of watchdog device
347 * @inode: inode structure
348 * @file: file structure
349 *
350 * returns 0 on success, -EBUSY if the file has been opened already, <0 on
351 * other failures
352 *
353 * function called when watchdog device is opened
354 */
355static int wdrtas_open(struct inode *inode, struct file *file)
356{
357 /* only open once */
358 if (atomic_inc_return(&wdrtas_miscdev_open) > 1) {
359 atomic_dec(&wdrtas_miscdev_open);
360 return -EBUSY;
361 }
362
363 wdrtas_timer_start();
364 wdrtas_timer_keepalive();
365
366 return stream_open(inode, file);
367}
368
369/**
370 * wdrtas_close - close function of watchdog device
371 * @inode: inode structure
372 * @file: file structure
373 *
374 * returns 0 on success
375 *
376 * close function. Always succeeds
377 */
378static int wdrtas_close(struct inode *inode, struct file *file)
379{
380 /* only stop watchdog, if this was announced using 'V' before */
381 if (wdrtas_expect_close == WDRTAS_MAGIC_CHAR)
382 wdrtas_timer_stop();
383 else {
384 pr_warn("got unexpected close. Watchdog not stopped.\n");
385 wdrtas_timer_keepalive();
386 }
387
388 wdrtas_expect_close = 0;
389 atomic_dec(&wdrtas_miscdev_open);
390 return 0;
391}
392
393/**
394 * wdrtas_temp_read - gives back the temperature in fahrenheit
395 * @file: file structure
396 * @buf: user buffer
397 * @count: number of bytes to be read
398 * @ppos: position in file
399 *
400 * returns always 1 or -EFAULT in case of user space copy failures, <0 on
401 * other failures
402 *
403 * wdrtas_temp_read gives the temperature to the users by copying this
404 * value as one byte into the user space buffer. The unit is Fahrenheit...
405 */
406static ssize_t wdrtas_temp_read(struct file *file, char __user *buf,
407 size_t count, loff_t *ppos)
408{
409 int temperature = 0;
410
411 temperature = wdrtas_get_temperature();
412 if (temperature < 0)
413 return temperature;
414
415 if (copy_to_user(buf, &temperature, 1))
416 return -EFAULT;
417
418 return 1;
419}
420
421/**
422 * wdrtas_temp_open - open function of temperature device
423 * @inode: inode structure
424 * @file: file structure
425 *
426 * returns 0 on success, <0 on failure
427 *
428 * function called when temperature device is opened
429 */
430static int wdrtas_temp_open(struct inode *inode, struct file *file)
431{
432 return stream_open(inode, file);
433}
434
435/**
436 * wdrtas_temp_close - close function of temperature device
437 * @inode: inode structure
438 * @file: file structure
439 *
440 * returns 0 on success
441 *
442 * close function. Always succeeds
443 */
444static int wdrtas_temp_close(struct inode *inode, struct file *file)
445{
446 return 0;
447}
448
449/**
450 * wdrtas_reboot - reboot notifier function
451 * @nb: notifier block structure
452 * @code: reboot code
453 * @ptr: unused
454 *
455 * returns NOTIFY_DONE
456 *
457 * wdrtas_reboot stops the watchdog in case of a reboot
458 */
459static int wdrtas_reboot(struct notifier_block *this,
460 unsigned long code, void *ptr)
461{
462 if (code == SYS_DOWN || code == SYS_HALT)
463 wdrtas_timer_stop();
464
465 return NOTIFY_DONE;
466}
467
468/*** initialization stuff */
469
470static const struct file_operations wdrtas_fops = {
471 .owner = THIS_MODULE,
472 .llseek = no_llseek,
473 .write = wdrtas_write,
474 .unlocked_ioctl = wdrtas_ioctl,
475 .compat_ioctl = compat_ptr_ioctl,
476 .open = wdrtas_open,
477 .release = wdrtas_close,
478};
479
480static struct miscdevice wdrtas_miscdev = {
481 .minor = WATCHDOG_MINOR,
482 .name = "watchdog",
483 .fops = &wdrtas_fops,
484};
485
486static const struct file_operations wdrtas_temp_fops = {
487 .owner = THIS_MODULE,
488 .llseek = no_llseek,
489 .read = wdrtas_temp_read,
490 .open = wdrtas_temp_open,
491 .release = wdrtas_temp_close,
492};
493
494static struct miscdevice wdrtas_tempdev = {
495 .minor = TEMP_MINOR,
496 .name = "temperature",
497 .fops = &wdrtas_temp_fops,
498};
499
500static struct notifier_block wdrtas_notifier = {
501 .notifier_call = wdrtas_reboot,
502};
503
504/**
505 * wdrtas_get_tokens - reads in RTAS tokens
506 *
507 * returns 0 on success, <0 on failure
508 *
509 * wdrtas_get_tokens reads in the tokens for the RTAS calls used in
510 * this watchdog driver. It tolerates, if "get-sensor-state" and
511 * "ibm,get-system-parameter" are not available.
512 */
513static int wdrtas_get_tokens(void)
514{
515 wdrtas_token_get_sensor_state = rtas_token("get-sensor-state");
516 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) {
517 pr_warn("couldn't get token for get-sensor-state. Trying to continue without temperature support.\n");
518 }
519
520 wdrtas_token_get_sp = rtas_token("ibm,get-system-parameter");
521 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) {
522 pr_warn("couldn't get token for ibm,get-system-parameter. Trying to continue with a default timeout value of %i seconds.\n",
523 WDRTAS_DEFAULT_INTERVAL);
524 }
525
526 wdrtas_token_set_indicator = rtas_token("set-indicator");
527 if (wdrtas_token_set_indicator == RTAS_UNKNOWN_SERVICE) {
528 pr_err("couldn't get token for set-indicator. Terminating watchdog code.\n");
529 return -EIO;
530 }
531
532 wdrtas_token_event_scan = rtas_token("event-scan");
533 if (wdrtas_token_event_scan == RTAS_UNKNOWN_SERVICE) {
534 pr_err("couldn't get token for event-scan. Terminating watchdog code.\n");
535 return -EIO;
536 }
537
538 return 0;
539}
540
541/**
542 * wdrtas_unregister_devs - unregisters the misc dev handlers
543 *
544 * wdrtas_register_devs unregisters the watchdog and temperature watchdog
545 * misc devs
546 */
547static void wdrtas_unregister_devs(void)
548{
549 misc_deregister(&wdrtas_miscdev);
550 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE)
551 misc_deregister(&wdrtas_tempdev);
552}
553
554/**
555 * wdrtas_register_devs - registers the misc dev handlers
556 *
557 * returns 0 on success, <0 on failure
558 *
559 * wdrtas_register_devs registers the watchdog and temperature watchdog
560 * misc devs
561 */
562static int wdrtas_register_devs(void)
563{
564 int result;
565
566 result = misc_register(&wdrtas_miscdev);
567 if (result) {
568 pr_err("couldn't register watchdog misc device. Terminating watchdog code.\n");
569 return result;
570 }
571
572 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) {
573 result = misc_register(&wdrtas_tempdev);
574 if (result) {
575 pr_warn("couldn't register watchdog temperature misc device. Continuing without temperature support.\n");
576 wdrtas_token_get_sensor_state = RTAS_UNKNOWN_SERVICE;
577 }
578 }
579
580 return 0;
581}
582
583/**
584 * wdrtas_init - init function of the watchdog driver
585 *
586 * returns 0 on success, <0 on failure
587 *
588 * registers the file handlers and the reboot notifier
589 */
590static int __init wdrtas_init(void)
591{
592 if (wdrtas_get_tokens())
593 return -ENODEV;
594
595 if (wdrtas_register_devs())
596 return -ENODEV;
597
598 if (register_reboot_notifier(&wdrtas_notifier)) {
599 pr_err("could not register reboot notifier. Terminating watchdog code.\n");
600 wdrtas_unregister_devs();
601 return -ENODEV;
602 }
603
604 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
605 wdrtas_interval = WDRTAS_DEFAULT_INTERVAL;
606 else
607 wdrtas_interval = wdrtas_get_interval(WDRTAS_DEFAULT_INTERVAL);
608
609 return 0;
610}
611
612/**
613 * wdrtas_exit - exit function of the watchdog driver
614 *
615 * unregisters the file handlers and the reboot notifier
616 */
617static void __exit wdrtas_exit(void)
618{
619 if (!wdrtas_nowayout)
620 wdrtas_timer_stop();
621
622 wdrtas_unregister_devs();
623
624 unregister_reboot_notifier(&wdrtas_notifier);
625}
626
627module_init(wdrtas_init);
628module_exit(wdrtas_exit);
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
48MODULE_AUTHOR("Utz Bacher <utz.bacher@de.ibm.com>");
49MODULE_DESCRIPTION("RTAS watchdog driver");
50MODULE_LICENSE("GPL");
51
52static bool wdrtas_nowayout = WATCHDOG_NOWAYOUT;
53static atomic_t wdrtas_miscdev_open = ATOMIC_INIT(0);
54static char wdrtas_expect_close;
55
56static int wdrtas_interval;
57
58#define WDRTAS_THERMAL_SENSOR 3
59static int wdrtas_token_get_sensor_state;
60#define WDRTAS_SURVEILLANCE_IND 9000
61static int wdrtas_token_set_indicator;
62#define WDRTAS_SP_SPI 28
63static int wdrtas_token_get_sp;
64static int wdrtas_token_event_scan;
65
66#define WDRTAS_DEFAULT_INTERVAL 300
67
68#define WDRTAS_LOGBUFFER_LEN 128
69static 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
85static 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 */
116static 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 */
146static 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 */
157static 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 */
169static 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 */
195static 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 */
216static 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 */
227static 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 */
247static 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
270out:
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
285static 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 */
368static 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 */
391static 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 */
419static 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 */
443static 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 */
457static 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 */
472static 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
483static 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
492static struct miscdevice wdrtas_miscdev = {
493 .minor = WATCHDOG_MINOR,
494 .name = "watchdog",
495 .fops = &wdrtas_fops,
496};
497
498static 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
506static struct miscdevice wdrtas_tempdev = {
507 .minor = TEMP_MINOR,
508 .name = "temperature",
509 .fops = &wdrtas_temp_fops,
510};
511
512static 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 */
525static 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 */
559static 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 */
574static 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 */
602static 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 */
629static 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
639module_init(wdrtas_init);
640module_exit(wdrtas_exit);