2 * FIXME: add wdrtas_get_status and wdrtas_get_boot_status as soon as
3 * RTAS calls are available
9 * (C) Copyright IBM Corp. 2005
10 * device driver to exploit watchdog RTAS functions
12 * Authors : Utz Bacher <utz.bacher@de.ibm.com>
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)
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.
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.
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>
42 #define WDRTAS_MAGIC_CHAR 42
43 #define WDRTAS_SUPPORTED_MASK (WDIOF_SETTIMEOUT | \
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);
52 static int wdrtas_nowayout = WATCHDOG_NOWAYOUT;
53 static atomic_t wdrtas_miscdev_open = ATOMIC_INIT(0);
54 static char wdrtas_expect_close;
56 static int wdrtas_interval;
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;
66 #define WDRTAS_DEFAULT_INTERVAL 300
68 #define WDRTAS_LOGBUFFER_LEN 128
69 static char wdrtas_logbuffer[WDRTAS_LOGBUFFER_LEN];
72 /*** watchdog access functions */
75 * wdrtas_set_interval - sets the watchdog interval
76 * @interval: new interval
78 * returns 0 on success, <0 on failures
80 * wdrtas_set_interval sets the watchdog keepalive interval by calling the
81 * RTAS function set-indicator (surveillance). The unit of interval is
85 static int wdrtas_set_interval(int interval)
88 static int print_msg = 10;
90 /* rtas uses minutes */
91 interval = (interval + 59) / 60;
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);
104 #define WDRTAS_SP_SPI_LEN 4
107 * wdrtas_get_interval - returns the current watchdog interval
108 * @fallback_value: value (in seconds) to use, if the RTAS call fails
110 * returns the interval
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.
116 static int wdrtas_get_interval(int fallback_value)
119 char value[WDRTAS_SP_SPI_LEN];
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),
127 memcpy(value, rtas_data_buf, WDRTAS_SP_SPI_LEN);
128 spin_unlock(&rtas_data_buf_lock);
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;
136 /* rtas uses minutes */
137 return ((int)value[2]) * 60;
141 * wdrtas_timer_start - starts watchdog
143 * wdrtas_timer_start starts the watchdog by calling the RTAS function
144 * set-interval (surveillance)
146 static void wdrtas_timer_start(void)
148 wdrtas_set_interval(wdrtas_interval);
152 * wdrtas_timer_stop - stops watchdog
154 * wdrtas_timer_stop stops the watchdog timer by calling the RTAS function
155 * set-interval (surveillance)
157 static void wdrtas_timer_stop(void)
159 wdrtas_set_interval(0);
163 * wdrtas_log_scanned_event - logs an event we received during keepalive
165 * wdrtas_log_scanned_event prints a message to the log buffer dumping
166 * the results of the last event-scan call
168 static void wdrtas_log_scanned_event(void)
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]);
188 * wdrtas_timer_keepalive - resets watchdog timer to keep system alive
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.
194 static void wdrtas_timer_keepalive(void)
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);
204 printk(KERN_ERR "wdrtas: event-scan failed: %li\n",
207 wdrtas_log_scanned_event();
208 } while (result == 0);
212 * wdrtas_get_temperature - returns current temperature
214 * returns temperature or <0 on failures
216 * wdrtas_get_temperature returns the current temperature in Fahrenheit. It
217 * uses the RTAS call get-sensor-state, token 3 to do so
219 static int wdrtas_get_temperature(void)
224 result = rtas_call(wdrtas_token_get_sensor_state, 2, 2,
225 (void *)__pa(&temperature),
226 WDRTAS_THERMAL_SENSOR, 0);
229 printk(KERN_WARNING "wdrtas: reading the thermal sensor "
230 "faild: %li\n", result);
232 temperature = ((temperature * 9) / 5) + 32; /* fahrenheit */
238 * wdrtas_get_status - returns the status of the watchdog
240 * returns a bitmask of defines WDIOF_... as defined in
241 * include/linux/watchdog.h
243 static int wdrtas_get_status(void)
249 * wdrtas_get_boot_status - returns the reason for the last boot
251 * returns a bitmask of defines WDIOF_... as defined in
252 * include/linux/watchdog.h, indicating why the watchdog rebooted the system
254 static int wdrtas_get_boot_status(void)
259 /*** watchdog API and operations stuff */
261 /* wdrtas_write - called when watchdog device is written to
262 * @file: file structure
263 * @buf: user buffer with data
264 * @len: amount to data written
265 * @ppos: position in file
267 * returns the number of successfully processed characters, which is always
268 * the number of bytes passed to this function
270 * wdrtas_write processes all the data given to it and looks for the magic
271 * character 'V'. This character allows the watchdog device to be closed
274 static ssize_t wdrtas_write(struct file *file, const char __user *buf,
275 size_t len, loff_t *ppos)
283 if (!wdrtas_nowayout) {
284 wdrtas_expect_close = 0;
286 for (i = 0; i < len; i++) {
287 if (get_user(c, buf + i))
289 /* allow to close device */
291 wdrtas_expect_close = WDRTAS_MAGIC_CHAR;
295 wdrtas_timer_keepalive();
302 * wdrtas_ioctl - ioctl function for the watchdog device
303 * @file: file structure
304 * @cmd: command for ioctl
305 * @arg: argument pointer
307 * returns 0 on success, <0 on failure
309 * wdrtas_ioctl implements the watchdog API ioctls
312 static long wdrtas_ioctl(struct file *file, unsigned int cmd,
315 int __user *argp = (void __user *)arg;
317 static struct watchdog_info wdinfo = {
318 .options = WDRTAS_SUPPORTED_MASK,
319 .firmware_version = 0,
320 .identity = "wdrtas",
324 case WDIOC_GETSUPPORT:
325 if (copy_to_user(argp, &wdinfo, sizeof(wdinfo)))
329 case WDIOC_GETSTATUS:
330 i = wdrtas_get_status();
331 return put_user(i, argp);
333 case WDIOC_GETBOOTSTATUS:
334 i = wdrtas_get_boot_status();
335 return put_user(i, argp);
338 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE)
341 i = wdrtas_get_temperature();
342 return put_user(i, argp);
344 case WDIOC_SETOPTIONS:
345 if (get_user(i, argp))
347 if (i & WDIOS_DISABLECARD)
349 if (i & WDIOS_ENABLECARD) {
350 wdrtas_timer_keepalive();
351 wdrtas_timer_start();
353 /* not implemented. Done by H8
354 if (i & WDIOS_TEMPPANIC) {
358 case WDIOC_KEEPALIVE:
359 wdrtas_timer_keepalive();
362 case WDIOC_SETTIMEOUT:
363 if (get_user(i, argp))
366 if (wdrtas_set_interval(i))
369 wdrtas_timer_keepalive();
371 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
374 wdrtas_interval = wdrtas_get_interval(i);
377 case WDIOC_GETTIMEOUT:
378 return put_user(wdrtas_interval, argp);
386 * wdrtas_open - open function of watchdog device
387 * @inode: inode structure
388 * @file: file structure
390 * returns 0 on success, -EBUSY if the file has been opened already, <0 on
393 * function called when watchdog device is opened
395 static int wdrtas_open(struct inode *inode, struct file *file)
398 if (atomic_inc_return(&wdrtas_miscdev_open) > 1) {
399 atomic_dec(&wdrtas_miscdev_open);
403 wdrtas_timer_start();
404 wdrtas_timer_keepalive();
406 return nonseekable_open(inode, file);
410 * wdrtas_close - close function of watchdog device
411 * @inode: inode structure
412 * @file: file structure
414 * returns 0 on success
416 * close function. Always succeeds
418 static int wdrtas_close(struct inode *inode, struct file *file)
420 /* only stop watchdog, if this was announced using 'V' before */
421 if (wdrtas_expect_close == WDRTAS_MAGIC_CHAR)
424 printk(KERN_WARNING "wdrtas: got unexpected close. Watchdog "
426 wdrtas_timer_keepalive();
429 wdrtas_expect_close = 0;
430 atomic_dec(&wdrtas_miscdev_open);
435 * wdrtas_temp_read - gives back the temperature in fahrenheit
436 * @file: file structure
438 * @count: number of bytes to be read
439 * @ppos: position in file
441 * returns always 1 or -EFAULT in case of user space copy failures, <0 on
444 * wdrtas_temp_read gives the temperature to the users by copying this
445 * value as one byte into the user space buffer. The unit is Fahrenheit...
447 static ssize_t wdrtas_temp_read(struct file *file, char __user *buf,
448 size_t count, loff_t *ppos)
452 temperature = wdrtas_get_temperature();
456 if (copy_to_user(buf, &temperature, 1))
463 * wdrtas_temp_open - open function of temperature device
464 * @inode: inode structure
465 * @file: file structure
467 * returns 0 on success, <0 on failure
469 * function called when temperature device is opened
471 static int wdrtas_temp_open(struct inode *inode, struct file *file)
473 return nonseekable_open(inode, file);
477 * wdrtas_temp_close - close function of temperature device
478 * @inode: inode structure
479 * @file: file structure
481 * returns 0 on success
483 * close function. Always succeeds
485 static int wdrtas_temp_close(struct inode *inode, struct file *file)
491 * wdrtas_reboot - reboot notifier function
492 * @nb: notifier block structure
496 * returns NOTIFY_DONE
498 * wdrtas_reboot stops the watchdog in case of a reboot
500 static int wdrtas_reboot(struct notifier_block *this,
501 unsigned long code, void *ptr)
503 if (code == SYS_DOWN || code == SYS_HALT)
509 /*** initialization stuff */
511 static const struct file_operations wdrtas_fops = {
512 .owner = THIS_MODULE,
514 .write = wdrtas_write,
515 .unlocked_ioctl = wdrtas_ioctl,
517 .release = wdrtas_close,
520 static struct miscdevice wdrtas_miscdev = {
521 .minor = WATCHDOG_MINOR,
523 .fops = &wdrtas_fops,
526 static const struct file_operations wdrtas_temp_fops = {
527 .owner = THIS_MODULE,
529 .read = wdrtas_temp_read,
530 .open = wdrtas_temp_open,
531 .release = wdrtas_temp_close,
534 static struct miscdevice wdrtas_tempdev = {
536 .name = "temperature",
537 .fops = &wdrtas_temp_fops,
540 static struct notifier_block wdrtas_notifier = {
541 .notifier_call = wdrtas_reboot,
545 * wdrtas_get_tokens - reads in RTAS tokens
547 * returns 0 on succes, <0 on failure
549 * wdrtas_get_tokens reads in the tokens for the RTAS calls used in
550 * this watchdog driver. It tolerates, if "get-sensor-state" and
551 * "ibm,get-system-parameter" are not available.
553 static int wdrtas_get_tokens(void)
555 wdrtas_token_get_sensor_state = rtas_token("get-sensor-state");
556 if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) {
557 printk(KERN_WARNING "wdrtas: couldn't get token for "
558 "get-sensor-state. Trying to continue without "
559 "temperature support.\n");
562 wdrtas_token_get_sp = rtas_token("ibm,get-system-parameter");
563 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) {
564 printk(KERN_WARNING "wdrtas: couldn't get token for "
565 "ibm,get-system-parameter. Trying to continue with "
566 "a default timeout value of %i seconds.\n",
567 WDRTAS_DEFAULT_INTERVAL);
570 wdrtas_token_set_indicator = rtas_token("set-indicator");
571 if (wdrtas_token_set_indicator == RTAS_UNKNOWN_SERVICE) {
572 printk(KERN_ERR "wdrtas: couldn't get token for "
573 "set-indicator. Terminating watchdog code.\n");
577 wdrtas_token_event_scan = rtas_token("event-scan");
578 if (wdrtas_token_event_scan == RTAS_UNKNOWN_SERVICE) {
579 printk(KERN_ERR "wdrtas: couldn't get token for event-scan. "
580 "Terminating watchdog code.\n");
588 * wdrtas_unregister_devs - unregisters the misc dev handlers
590 * wdrtas_register_devs unregisters the watchdog and temperature watchdog
593 static void wdrtas_unregister_devs(void)
595 misc_deregister(&wdrtas_miscdev);
596 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE)
597 misc_deregister(&wdrtas_tempdev);
601 * wdrtas_register_devs - registers the misc dev handlers
603 * returns 0 on succes, <0 on failure
605 * wdrtas_register_devs registers the watchdog and temperature watchdog
608 static int wdrtas_register_devs(void)
612 result = misc_register(&wdrtas_miscdev);
614 printk(KERN_ERR "wdrtas: couldn't register watchdog misc "
615 "device. Terminating watchdog code.\n");
619 if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) {
620 result = misc_register(&wdrtas_tempdev);
622 printk(KERN_WARNING "wdrtas: couldn't register "
623 "watchdog temperature misc device. Continuing "
624 "without temperature support.\n");
625 wdrtas_token_get_sensor_state = RTAS_UNKNOWN_SERVICE;
633 * wdrtas_init - init function of the watchdog driver
635 * returns 0 on succes, <0 on failure
637 * registers the file handlers and the reboot notifier
639 static int __init wdrtas_init(void)
641 if (wdrtas_get_tokens())
644 if (wdrtas_register_devs())
647 if (register_reboot_notifier(&wdrtas_notifier)) {
648 printk(KERN_ERR "wdrtas: could not register reboot notifier. "
649 "Terminating watchdog code.\n");
650 wdrtas_unregister_devs();
654 if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
655 wdrtas_interval = WDRTAS_DEFAULT_INTERVAL;
657 wdrtas_interval = wdrtas_get_interval(WDRTAS_DEFAULT_INTERVAL);
663 * wdrtas_exit - exit function of the watchdog driver
665 * unregisters the file handlers and the reboot notifier
667 static void __exit wdrtas_exit(void)
669 if (!wdrtas_nowayout)
672 wdrtas_unregister_devs();
674 unregister_reboot_notifier(&wdrtas_notifier);
677 module_init(wdrtas_init);
678 module_exit(wdrtas_exit);