Root/drivers/watchdog/wdrtas.c

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");
51MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
52MODULE_ALIAS_MISCDEV(TEMP_MINOR);
53
54static bool wdrtas_nowayout = WATCHDOG_NOWAYOUT;
55static atomic_t wdrtas_miscdev_open = ATOMIC_INIT(0);
56static char wdrtas_expect_close;
57
58static int wdrtas_interval;
59
60#define WDRTAS_THERMAL_SENSOR 3
61static int wdrtas_token_get_sensor_state;
62#define WDRTAS_SURVEILLANCE_IND 9000
63static int wdrtas_token_set_indicator;
64#define WDRTAS_SP_SPI 28
65static int wdrtas_token_get_sp;
66static int wdrtas_token_event_scan;
67
68#define WDRTAS_DEFAULT_INTERVAL 300
69
70#define WDRTAS_LOGBUFFER_LEN 128
71static char wdrtas_logbuffer[WDRTAS_LOGBUFFER_LEN];
72
73
74/*** watchdog access functions */
75
76/**
77 * wdrtas_set_interval - sets the watchdog interval
78 * @interval: new interval
79 *
80 * returns 0 on success, <0 on failures
81 *
82 * wdrtas_set_interval sets the watchdog keepalive interval by calling the
83 * RTAS function set-indicator (surveillance). The unit of interval is
84 * seconds.
85 */
86
87static int wdrtas_set_interval(int interval)
88{
89    long result;
90    static int print_msg = 10;
91
92    /* rtas uses minutes */
93    interval = (interval + 59) / 60;
94
95    result = rtas_call(wdrtas_token_set_indicator, 3, 1, NULL,
96               WDRTAS_SURVEILLANCE_IND, 0, interval);
97    if (result < 0 && print_msg) {
98        pr_err("setting the watchdog to %i timeout failed: %li\n",
99               interval, result);
100        print_msg--;
101    }
102
103    return result;
104}
105
106#define WDRTAS_SP_SPI_LEN 4
107
108/**
109 * wdrtas_get_interval - returns the current watchdog interval
110 * @fallback_value: value (in seconds) to use, if the RTAS call fails
111 *
112 * returns the interval
113 *
114 * wdrtas_get_interval returns the current watchdog keepalive interval
115 * as reported by the RTAS function ibm,get-system-parameter. The unit
116 * of the return value is seconds.
117 */
118static int wdrtas_get_interval(int fallback_value)
119{
120    long result;
121    char value[WDRTAS_SP_SPI_LEN];
122
123    spin_lock(&rtas_data_buf_lock);
124    memset(rtas_data_buf, 0, WDRTAS_SP_SPI_LEN);
125    result = rtas_call(wdrtas_token_get_sp, 3, 1, NULL,
126               WDRTAS_SP_SPI, __pa(rtas_data_buf),
127               WDRTAS_SP_SPI_LEN);
128
129    memcpy(value, rtas_data_buf, WDRTAS_SP_SPI_LEN);
130    spin_unlock(&rtas_data_buf_lock);
131
132    if (value[0] != 0 || value[1] != 2 || value[3] != 0 || result < 0) {
133        pr_warn("could not get sp_spi watchdog timeout (%li). Continuing\n",
134            result);
135        return fallback_value;
136    }
137
138    /* rtas uses minutes */
139    return ((int)value[2]) * 60;
140}
141
142/**
143 * wdrtas_timer_start - starts watchdog
144 *
145 * wdrtas_timer_start starts the watchdog by calling the RTAS function
146 * set-interval (surveillance)
147 */
148static void wdrtas_timer_start(void)
149{
150    wdrtas_set_interval(wdrtas_interval);
151}
152
153/**
154 * wdrtas_timer_stop - stops watchdog
155 *
156 * wdrtas_timer_stop stops the watchdog timer by calling the RTAS function
157 * set-interval (surveillance)
158 */
159static void wdrtas_timer_stop(void)
160{
161    wdrtas_set_interval(0);
162}
163
164/**
165 * wdrtas_log_scanned_event - logs an event we received during keepalive
166 *
167 * wdrtas_log_scanned_event prints a message to the log buffer dumping
168 * the results of the last event-scan call
169 */
170static void wdrtas_log_scanned_event(void)
171{
172    int i;
173
174    for (i = 0; i < WDRTAS_LOGBUFFER_LEN; i += 16)
175        pr_info("dumping event (line %i/%i), data = "
176            "%02x %02x %02x %02x %02x %02x %02x %02x "
177            "%02x %02x %02x %02x %02x %02x %02x %02x\n",
178            (i / 16) + 1, (WDRTAS_LOGBUFFER_LEN / 16),
179            wdrtas_logbuffer[i + 0], wdrtas_logbuffer[i + 1],
180            wdrtas_logbuffer[i + 2], wdrtas_logbuffer[i + 3],
181            wdrtas_logbuffer[i + 4], wdrtas_logbuffer[i + 5],
182            wdrtas_logbuffer[i + 6], wdrtas_logbuffer[i + 7],
183            wdrtas_logbuffer[i + 8], wdrtas_logbuffer[i + 9],
184            wdrtas_logbuffer[i + 10], wdrtas_logbuffer[i + 11],
185            wdrtas_logbuffer[i + 12], wdrtas_logbuffer[i + 13],
186            wdrtas_logbuffer[i + 14], wdrtas_logbuffer[i + 15]);
187}
188
189/**
190 * wdrtas_timer_keepalive - resets watchdog timer to keep system alive
191 *
192 * wdrtas_timer_keepalive restarts the watchdog timer by calling the
193 * RTAS function event-scan and repeats these calls as long as there are
194 * events available. All events will be dumped.
195 */
196static void wdrtas_timer_keepalive(void)
197{
198    long result;
199
200    do {
201        result = rtas_call(wdrtas_token_event_scan, 4, 1, NULL,
202                   RTAS_EVENT_SCAN_ALL_EVENTS, 0,
203                   (void *)__pa(wdrtas_logbuffer),
204                   WDRTAS_LOGBUFFER_LEN);
205        if (result < 0)
206            pr_err("event-scan failed: %li\n", result);
207        if (result == 0)
208            wdrtas_log_scanned_event();
209    } while (result == 0);
210}
211
212/**
213 * wdrtas_get_temperature - returns current temperature
214 *
215 * returns temperature or <0 on failures
216 *
217 * wdrtas_get_temperature returns the current temperature in Fahrenheit. It
218 * uses the RTAS call get-sensor-state, token 3 to do so
219 */
220static int wdrtas_get_temperature(void)
221{
222    int result;
223    int temperature = 0;
224
225    result = rtas_get_sensor(WDRTAS_THERMAL_SENSOR, 0, &temperature);
226
227    if (result < 0)
228        pr_warn("reading the thermal sensor 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 */
241static 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 */
252static 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 */
272static 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
295out:
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
310static 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 */
393static 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 */
416static 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        pr_warn("got unexpected close. Watchdog not stopped.\n");
423        wdrtas_timer_keepalive();
424    }
425
426    wdrtas_expect_close = 0;
427    atomic_dec(&wdrtas_miscdev_open);
428    return 0;
429}
430
431/**
432 * wdrtas_temp_read - gives back the temperature in fahrenheit
433 * @file: file structure
434 * @buf: user buffer
435 * @count: number of bytes to be read
436 * @ppos: position in file
437 *
438 * returns always 1 or -EFAULT in case of user space copy failures, <0 on
439 * other failures
440 *
441 * wdrtas_temp_read gives the temperature to the users by copying this
442 * value as one byte into the user space buffer. The unit is Fahrenheit...
443 */
444static ssize_t wdrtas_temp_read(struct file *file, char __user *buf,
445         size_t count, loff_t *ppos)
446{
447    int temperature = 0;
448
449    temperature = wdrtas_get_temperature();
450    if (temperature < 0)
451        return temperature;
452
453    if (copy_to_user(buf, &temperature, 1))
454        return -EFAULT;
455
456    return 1;
457}
458
459/**
460 * wdrtas_temp_open - open function of temperature device
461 * @inode: inode structure
462 * @file: file structure
463 *
464 * returns 0 on success, <0 on failure
465 *
466 * function called when temperature device is opened
467 */
468static int wdrtas_temp_open(struct inode *inode, struct file *file)
469{
470    return nonseekable_open(inode, file);
471}
472
473/**
474 * wdrtas_temp_close - close function of temperature device
475 * @inode: inode structure
476 * @file: file structure
477 *
478 * returns 0 on success
479 *
480 * close function. Always succeeds
481 */
482static int wdrtas_temp_close(struct inode *inode, struct file *file)
483{
484    return 0;
485}
486
487/**
488 * wdrtas_reboot - reboot notifier function
489 * @nb: notifier block structure
490 * @code: reboot code
491 * @ptr: unused
492 *
493 * returns NOTIFY_DONE
494 *
495 * wdrtas_reboot stops the watchdog in case of a reboot
496 */
497static int wdrtas_reboot(struct notifier_block *this,
498                    unsigned long code, void *ptr)
499{
500    if (code == SYS_DOWN || code == SYS_HALT)
501        wdrtas_timer_stop();
502
503    return NOTIFY_DONE;
504}
505
506/*** initialization stuff */
507
508static const struct file_operations wdrtas_fops = {
509    .owner = THIS_MODULE,
510    .llseek = no_llseek,
511    .write = wdrtas_write,
512    .unlocked_ioctl = wdrtas_ioctl,
513    .open = wdrtas_open,
514    .release = wdrtas_close,
515};
516
517static struct miscdevice wdrtas_miscdev = {
518    .minor = WATCHDOG_MINOR,
519    .name = "watchdog",
520    .fops = &wdrtas_fops,
521};
522
523static const struct file_operations wdrtas_temp_fops = {
524    .owner = THIS_MODULE,
525    .llseek = no_llseek,
526    .read = wdrtas_temp_read,
527    .open = wdrtas_temp_open,
528    .release = wdrtas_temp_close,
529};
530
531static struct miscdevice wdrtas_tempdev = {
532    .minor = TEMP_MINOR,
533    .name = "temperature",
534    .fops = &wdrtas_temp_fops,
535};
536
537static struct notifier_block wdrtas_notifier = {
538    .notifier_call = wdrtas_reboot,
539};
540
541/**
542 * wdrtas_get_tokens - reads in RTAS tokens
543 *
544 * returns 0 on success, <0 on failure
545 *
546 * wdrtas_get_tokens reads in the tokens for the RTAS calls used in
547 * this watchdog driver. It tolerates, if "get-sensor-state" and
548 * "ibm,get-system-parameter" are not available.
549 */
550static int wdrtas_get_tokens(void)
551{
552    wdrtas_token_get_sensor_state = rtas_token("get-sensor-state");
553    if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) {
554        pr_warn("couldn't get token for get-sensor-state. Trying to continue without temperature support.\n");
555    }
556
557    wdrtas_token_get_sp = rtas_token("ibm,get-system-parameter");
558    if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) {
559        pr_warn("couldn't get token for ibm,get-system-parameter. Trying to continue with a default timeout value of %i seconds.\n",
560            WDRTAS_DEFAULT_INTERVAL);
561    }
562
563    wdrtas_token_set_indicator = rtas_token("set-indicator");
564    if (wdrtas_token_set_indicator == RTAS_UNKNOWN_SERVICE) {
565        pr_err("couldn't get token for set-indicator. Terminating watchdog code.\n");
566        return -EIO;
567    }
568
569    wdrtas_token_event_scan = rtas_token("event-scan");
570    if (wdrtas_token_event_scan == RTAS_UNKNOWN_SERVICE) {
571        pr_err("couldn't get token for event-scan. Terminating watchdog code.\n");
572        return -EIO;
573    }
574
575    return 0;
576}
577
578/**
579 * wdrtas_unregister_devs - unregisters the misc dev handlers
580 *
581 * wdrtas_register_devs unregisters the watchdog and temperature watchdog
582 * misc devs
583 */
584static void wdrtas_unregister_devs(void)
585{
586    misc_deregister(&wdrtas_miscdev);
587    if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE)
588        misc_deregister(&wdrtas_tempdev);
589}
590
591/**
592 * wdrtas_register_devs - registers the misc dev handlers
593 *
594 * returns 0 on success, <0 on failure
595 *
596 * wdrtas_register_devs registers the watchdog and temperature watchdog
597 * misc devs
598 */
599static int wdrtas_register_devs(void)
600{
601    int result;
602
603    result = misc_register(&wdrtas_miscdev);
604    if (result) {
605        pr_err("couldn't register watchdog misc device. Terminating watchdog code.\n");
606        return result;
607    }
608
609    if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) {
610        result = misc_register(&wdrtas_tempdev);
611        if (result) {
612            pr_warn("couldn't register watchdog temperature misc device. Continuing without temperature support.\n");
613            wdrtas_token_get_sensor_state = RTAS_UNKNOWN_SERVICE;
614        }
615    }
616
617    return 0;
618}
619
620/**
621 * wdrtas_init - init function of the watchdog driver
622 *
623 * returns 0 on success, <0 on failure
624 *
625 * registers the file handlers and the reboot notifier
626 */
627static int __init wdrtas_init(void)
628{
629    if (wdrtas_get_tokens())
630        return -ENODEV;
631
632    if (wdrtas_register_devs())
633        return -ENODEV;
634
635    if (register_reboot_notifier(&wdrtas_notifier)) {
636        pr_err("could not register reboot notifier. Terminating watchdog code.\n");
637        wdrtas_unregister_devs();
638        return -ENODEV;
639    }
640
641    if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
642        wdrtas_interval = WDRTAS_DEFAULT_INTERVAL;
643    else
644        wdrtas_interval = wdrtas_get_interval(WDRTAS_DEFAULT_INTERVAL);
645
646    return 0;
647}
648
649/**
650 * wdrtas_exit - exit function of the watchdog driver
651 *
652 * unregisters the file handlers and the reboot notifier
653 */
654static void __exit wdrtas_exit(void)
655{
656    if (!wdrtas_nowayout)
657        wdrtas_timer_stop();
658
659    wdrtas_unregister_devs();
660
661    unregister_reboot_notifier(&wdrtas_notifier);
662}
663
664module_init(wdrtas_init);
665module_exit(wdrtas_exit);
666

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jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master

Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9



interactive