Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * drivers/char/watchdog/shwdt.c | |
3 | * | |
4 | * Watchdog driver for integrated watchdog in the SuperH processors. | |
5 | * | |
6 | * Copyright (C) 2001, 2002, 2003 Paul Mundt <lethal@linux-sh.org> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify it | |
9 | * under the terms of the GNU General Public License as published by the | |
10 | * Free Software Foundation; either version 2 of the License, or (at your | |
11 | * option) any later version. | |
12 | * | |
13 | * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> | |
14 | * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT | |
15 | * | |
16 | * 19-Apr-2002 Rob Radez <rob@osinvestor.com> | |
17 | * Added expect close support, made emulated timeout runtime changeable | |
18 | * general cleanups, add some ioctls | |
19 | */ | |
1da177e4 LT |
20 | #include <linux/module.h> |
21 | #include <linux/moduleparam.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/types.h> | |
24 | #include <linux/miscdevice.h> | |
25 | #include <linux/watchdog.h> | |
26 | #include <linux/reboot.h> | |
27 | #include <linux/notifier.h> | |
28 | #include <linux/ioport.h> | |
29 | #include <linux/fs.h> | |
f118420b | 30 | #include <linux/mm.h> |
70b814ec AC |
31 | #include <linux/io.h> |
32 | #include <linux/uaccess.h> | |
58cf4198 | 33 | #include <asm/watchdog.h> |
1da177e4 LT |
34 | |
35 | #define PFX "shwdt: " | |
36 | ||
37 | /* | |
38 | * Default clock division ratio is 5.25 msecs. For an additional table of | |
39 | * values, consult the asm-sh/watchdog.h. Overload this at module load | |
40 | * time. | |
41 | * | |
42 | * In order for this to work reliably we need to have HZ set to 1000 or | |
43 | * something quite higher than 100 (or we need a proper high-res timer | |
44 | * implementation that will deal with this properly), otherwise the 10ms | |
45 | * resolution of a jiffy is enough to trigger the overflow. For things like | |
46 | * the SH-4 and SH-5, this isn't necessarily that big of a problem, though | |
47 | * for the SH-2 and SH-3, this isn't recommended unless the WDT is absolutely | |
48 | * necssary. | |
49 | * | |
50 | * As a result of this timing problem, the only modes that are particularly | |
51 | * feasible are the 4096 and the 2048 divisors, which yeild 5.25 and 2.62ms | |
52 | * overflow periods respectively. | |
53 | * | |
54 | * Also, since we can't really expect userspace to be responsive enough | |
ee0fc097 | 55 | * before the overflow happens, we maintain two separate timers .. One in |
1da177e4 LT |
56 | * the kernel for clearing out WOVF every 2ms or so (again, this depends on |
57 | * HZ == 1000), and another for monitoring userspace writes to the WDT device. | |
58 | * | |
59 | * As such, we currently use a configurable heartbeat interval which defaults | |
60 | * to 30s. In this case, the userspace daemon is only responsible for periodic | |
61 | * writes to the device before the next heartbeat is scheduled. If the daemon | |
62 | * misses its deadline, the kernel timer will allow the WDT to overflow. | |
63 | */ | |
64 | static int clock_division_ratio = WTCSR_CKS_4096; | |
65 | ||
66 | #define next_ping_period(cks) msecs_to_jiffies(cks - 4) | |
67 | ||
82eb7c50 JS |
68 | static void sh_wdt_ping(unsigned long data); |
69 | ||
1da177e4 | 70 | static unsigned long shwdt_is_open; |
58cf4198 | 71 | static const struct watchdog_info sh_wdt_info; |
1da177e4 | 72 | static char shwdt_expect_close; |
82eb7c50 | 73 | static DEFINE_TIMER(timer, sh_wdt_ping, 0, 0); |
1da177e4 | 74 | static unsigned long next_heartbeat; |
70b814ec | 75 | static DEFINE_SPINLOCK(shwdt_lock); |
1da177e4 LT |
76 | |
77 | #define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat */ | |
78 | static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */ | |
79 | ||
4bfdf378 | 80 | static int nowayout = WATCHDOG_NOWAYOUT; |
1da177e4 LT |
81 | |
82 | /** | |
83 | * sh_wdt_start - Start the Watchdog | |
84 | * | |
85 | * Starts the watchdog. | |
86 | */ | |
87 | static void sh_wdt_start(void) | |
88 | { | |
89 | __u8 csr; | |
70b814ec AC |
90 | unsigned long flags; |
91 | ||
58cf4198 | 92 | spin_lock_irqsave(&shwdt_lock, flags); |
1da177e4 LT |
93 | |
94 | next_heartbeat = jiffies + (heartbeat * HZ); | |
95 | mod_timer(&timer, next_ping_period(clock_division_ratio)); | |
96 | ||
97 | csr = sh_wdt_read_csr(); | |
98 | csr |= WTCSR_WT | clock_division_ratio; | |
99 | sh_wdt_write_csr(csr); | |
100 | ||
101 | sh_wdt_write_cnt(0); | |
102 | ||
103 | /* | |
104 | * These processors have a bit of an inconsistent initialization | |
105 | * process.. starting with SH-3, RSTS was moved to WTCSR, and the | |
106 | * RSTCSR register was removed. | |
107 | * | |
108 | * On the SH-2 however, in addition with bits being in different | |
109 | * locations, we must deal with RSTCSR outright.. | |
110 | */ | |
111 | csr = sh_wdt_read_csr(); | |
112 | csr |= WTCSR_TME; | |
113 | csr &= ~WTCSR_RSTS; | |
114 | sh_wdt_write_csr(csr); | |
115 | ||
116 | #ifdef CONFIG_CPU_SH2 | |
117 | /* | |
118 | * Whoever came up with the RSTCSR semantics must've been smoking | |
119 | * some of the good stuff, since in addition to the WTCSR/WTCNT write | |
120 | * brain-damage, it's managed to fuck things up one step further.. | |
121 | * | |
122 | * If we need to clear the WOVF bit, the upper byte has to be 0xa5.. | |
123 | * but if we want to touch RSTE or RSTS, the upper byte has to be | |
124 | * 0x5a.. | |
125 | */ | |
126 | csr = sh_wdt_read_rstcsr(); | |
127 | csr &= ~RSTCSR_RSTS; | |
128 | sh_wdt_write_rstcsr(csr); | |
129 | #endif | |
58cf4198 | 130 | spin_unlock_irqrestore(&shwdt_lock, flags); |
1da177e4 LT |
131 | } |
132 | ||
133 | /** | |
134 | * sh_wdt_stop - Stop the Watchdog | |
1da177e4 LT |
135 | * Stops the watchdog. |
136 | */ | |
137 | static void sh_wdt_stop(void) | |
138 | { | |
139 | __u8 csr; | |
70b814ec AC |
140 | unsigned long flags; |
141 | ||
58cf4198 | 142 | spin_lock_irqsave(&shwdt_lock, flags); |
1da177e4 LT |
143 | |
144 | del_timer(&timer); | |
145 | ||
146 | csr = sh_wdt_read_csr(); | |
147 | csr &= ~WTCSR_TME; | |
148 | sh_wdt_write_csr(csr); | |
58cf4198 | 149 | spin_unlock_irqrestore(&shwdt_lock, flags); |
1da177e4 LT |
150 | } |
151 | ||
152 | /** | |
153 | * sh_wdt_keepalive - Keep the Userspace Watchdog Alive | |
1da177e4 LT |
154 | * The Userspace watchdog got a KeepAlive: schedule the next heartbeat. |
155 | */ | |
e4c2cfee | 156 | static inline void sh_wdt_keepalive(void) |
1da177e4 | 157 | { |
70b814ec AC |
158 | unsigned long flags; |
159 | ||
58cf4198 | 160 | spin_lock_irqsave(&shwdt_lock, flags); |
1da177e4 | 161 | next_heartbeat = jiffies + (heartbeat * HZ); |
58cf4198 | 162 | spin_unlock_irqrestore(&shwdt_lock, flags); |
1da177e4 LT |
163 | } |
164 | ||
165 | /** | |
166 | * sh_wdt_set_heartbeat - Set the Userspace Watchdog heartbeat | |
1da177e4 LT |
167 | * Set the Userspace Watchdog heartbeat |
168 | */ | |
169 | static int sh_wdt_set_heartbeat(int t) | |
170 | { | |
70b814ec AC |
171 | unsigned long flags; |
172 | ||
173 | if (unlikely(t < 1 || t > 3600)) /* arbitrary upper limit */ | |
1da177e4 LT |
174 | return -EINVAL; |
175 | ||
58cf4198 | 176 | spin_lock_irqsave(&shwdt_lock, flags); |
1da177e4 | 177 | heartbeat = t; |
58cf4198 | 178 | spin_unlock_irqrestore(&shwdt_lock, flags); |
1da177e4 LT |
179 | return 0; |
180 | } | |
181 | ||
182 | /** | |
183 | * sh_wdt_ping - Ping the Watchdog | |
1da177e4 LT |
184 | * @data: Unused |
185 | * | |
186 | * Clears overflow bit, resets timer counter. | |
187 | */ | |
188 | static void sh_wdt_ping(unsigned long data) | |
189 | { | |
70b814ec AC |
190 | unsigned long flags; |
191 | ||
58cf4198 | 192 | spin_lock_irqsave(&shwdt_lock, flags); |
1da177e4 LT |
193 | if (time_before(jiffies, next_heartbeat)) { |
194 | __u8 csr; | |
195 | ||
196 | csr = sh_wdt_read_csr(); | |
197 | csr &= ~WTCSR_IOVF; | |
198 | sh_wdt_write_csr(csr); | |
199 | ||
200 | sh_wdt_write_cnt(0); | |
201 | ||
202 | mod_timer(&timer, next_ping_period(clock_division_ratio)); | |
e4c2cfee PM |
203 | } else |
204 | printk(KERN_WARNING PFX "Heartbeat lost! Will not ping " | |
205 | "the watchdog\n"); | |
58cf4198 | 206 | spin_unlock_irqrestore(&shwdt_lock, flags); |
1da177e4 LT |
207 | } |
208 | ||
209 | /** | |
210 | * sh_wdt_open - Open the Device | |
1da177e4 LT |
211 | * @inode: inode of device |
212 | * @file: file handle of device | |
213 | * | |
214 | * Watchdog device is opened and started. | |
215 | */ | |
216 | static int sh_wdt_open(struct inode *inode, struct file *file) | |
217 | { | |
218 | if (test_and_set_bit(0, &shwdt_is_open)) | |
219 | return -EBUSY; | |
220 | if (nowayout) | |
221 | __module_get(THIS_MODULE); | |
222 | ||
223 | sh_wdt_start(); | |
224 | ||
225 | return nonseekable_open(inode, file); | |
226 | } | |
227 | ||
228 | /** | |
229 | * sh_wdt_close - Close the Device | |
1da177e4 LT |
230 | * @inode: inode of device |
231 | * @file: file handle of device | |
232 | * | |
233 | * Watchdog device is closed and stopped. | |
234 | */ | |
235 | static int sh_wdt_close(struct inode *inode, struct file *file) | |
236 | { | |
237 | if (shwdt_expect_close == 42) { | |
238 | sh_wdt_stop(); | |
239 | } else { | |
e4c2cfee PM |
240 | printk(KERN_CRIT PFX "Unexpected close, not " |
241 | "stopping watchdog!\n"); | |
1da177e4 LT |
242 | sh_wdt_keepalive(); |
243 | } | |
244 | ||
245 | clear_bit(0, &shwdt_is_open); | |
246 | shwdt_expect_close = 0; | |
247 | ||
248 | return 0; | |
249 | } | |
250 | ||
251 | /** | |
252 | * sh_wdt_write - Write to Device | |
1da177e4 LT |
253 | * @file: file handle of device |
254 | * @buf: buffer to write | |
255 | * @count: length of buffer | |
256 | * @ppos: offset | |
257 | * | |
258 | * Pings the watchdog on write. | |
259 | */ | |
260 | static ssize_t sh_wdt_write(struct file *file, const char *buf, | |
261 | size_t count, loff_t *ppos) | |
262 | { | |
263 | if (count) { | |
264 | if (!nowayout) { | |
265 | size_t i; | |
266 | ||
267 | shwdt_expect_close = 0; | |
268 | ||
269 | for (i = 0; i != count; i++) { | |
270 | char c; | |
271 | if (get_user(c, buf + i)) | |
272 | return -EFAULT; | |
273 | if (c == 'V') | |
274 | shwdt_expect_close = 42; | |
275 | } | |
276 | } | |
277 | sh_wdt_keepalive(); | |
278 | } | |
279 | ||
280 | return count; | |
281 | } | |
282 | ||
f118420b PM |
283 | /** |
284 | * sh_wdt_mmap - map WDT/CPG registers into userspace | |
285 | * @file: file structure for the device | |
286 | * @vma: VMA to map the registers into | |
287 | * | |
288 | * A simple mmap() implementation for the corner cases where the counter | |
289 | * needs to be mapped in userspace directly. Due to the relatively small | |
290 | * size of the area, neighbouring registers not necessarily tied to the | |
291 | * CPG will also be accessible through the register page, so this remains | |
292 | * configurable for users that really know what they're doing. | |
293 | * | |
294 | * Additionaly, the register page maps in the CPG register base relative | |
295 | * to the nearest page-aligned boundary, which requires that userspace do | |
296 | * the appropriate CPU subtype math for calculating the page offset for | |
297 | * the counter value. | |
298 | */ | |
299 | static int sh_wdt_mmap(struct file *file, struct vm_area_struct *vma) | |
300 | { | |
301 | int ret = -ENOSYS; | |
302 | ||
303 | #ifdef CONFIG_SH_WDT_MMAP | |
304 | unsigned long addr; | |
305 | ||
306 | /* Only support the simple cases where we map in a register page. */ | |
307 | if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff) | |
308 | return -EINVAL; | |
309 | ||
310 | /* | |
311 | * Pick WTCNT as the start, it's usually the first register after the | |
312 | * FRQCR, and neither one are generally page-aligned out of the box. | |
313 | */ | |
314 | addr = WTCNT & ~(PAGE_SIZE - 1); | |
315 | ||
316 | vma->vm_flags |= VM_IO; | |
317 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); | |
318 | ||
319 | if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT, | |
320 | PAGE_SIZE, vma->vm_page_prot)) { | |
321 | printk(KERN_ERR PFX "%s: io_remap_pfn_range failed\n", | |
fa9363c5 | 322 | __func__); |
f118420b PM |
323 | return -EAGAIN; |
324 | } | |
325 | ||
326 | ret = 0; | |
327 | #endif | |
328 | ||
329 | return ret; | |
330 | } | |
331 | ||
1da177e4 LT |
332 | /** |
333 | * sh_wdt_ioctl - Query Device | |
1da177e4 LT |
334 | * @file: file handle of device |
335 | * @cmd: watchdog command | |
336 | * @arg: argument | |
337 | * | |
338 | * Query basic information from the device or ping it, as outlined by the | |
339 | * watchdog API. | |
340 | */ | |
70b814ec AC |
341 | static long sh_wdt_ioctl(struct file *file, unsigned int cmd, |
342 | unsigned long arg) | |
1da177e4 LT |
343 | { |
344 | int new_heartbeat; | |
345 | int options, retval = -EINVAL; | |
346 | ||
347 | switch (cmd) { | |
70b814ec AC |
348 | case WDIOC_GETSUPPORT: |
349 | return copy_to_user((struct watchdog_info *)arg, | |
350 | &sh_wdt_info, sizeof(sh_wdt_info)) ? -EFAULT : 0; | |
351 | case WDIOC_GETSTATUS: | |
352 | case WDIOC_GETBOOTSTATUS: | |
353 | return put_user(0, (int *)arg); | |
70b814ec AC |
354 | case WDIOC_SETOPTIONS: |
355 | if (get_user(options, (int *)arg)) | |
356 | return -EFAULT; | |
357 | ||
358 | if (options & WDIOS_DISABLECARD) { | |
359 | sh_wdt_stop(); | |
360 | retval = 0; | |
361 | } | |
362 | ||
363 | if (options & WDIOS_ENABLECARD) { | |
364 | sh_wdt_start(); | |
365 | retval = 0; | |
366 | } | |
1da177e4 | 367 | |
70b814ec | 368 | return retval; |
0c06090c WVS |
369 | case WDIOC_KEEPALIVE: |
370 | sh_wdt_keepalive(); | |
371 | return 0; | |
372 | case WDIOC_SETTIMEOUT: | |
373 | if (get_user(new_heartbeat, (int *)arg)) | |
374 | return -EFAULT; | |
375 | ||
376 | if (sh_wdt_set_heartbeat(new_heartbeat)) | |
377 | return -EINVAL; | |
378 | ||
379 | sh_wdt_keepalive(); | |
380 | /* Fall */ | |
381 | case WDIOC_GETTIMEOUT: | |
382 | return put_user(heartbeat, (int *)arg); | |
70b814ec AC |
383 | default: |
384 | return -ENOTTY; | |
385 | } | |
1da177e4 LT |
386 | return 0; |
387 | } | |
388 | ||
389 | /** | |
390 | * sh_wdt_notify_sys - Notifier Handler | |
1da177e4 LT |
391 | * @this: notifier block |
392 | * @code: notifier event | |
393 | * @unused: unused | |
394 | * | |
395 | * Handles specific events, such as turning off the watchdog during a | |
396 | * shutdown event. | |
397 | */ | |
398 | static int sh_wdt_notify_sys(struct notifier_block *this, | |
399 | unsigned long code, void *unused) | |
400 | { | |
e4c2cfee | 401 | if (code == SYS_DOWN || code == SYS_HALT) |
1da177e4 | 402 | sh_wdt_stop(); |
1da177e4 LT |
403 | |
404 | return NOTIFY_DONE; | |
405 | } | |
406 | ||
62322d25 | 407 | static const struct file_operations sh_wdt_fops = { |
1da177e4 LT |
408 | .owner = THIS_MODULE, |
409 | .llseek = no_llseek, | |
410 | .write = sh_wdt_write, | |
70b814ec | 411 | .unlocked_ioctl = sh_wdt_ioctl, |
1da177e4 LT |
412 | .open = sh_wdt_open, |
413 | .release = sh_wdt_close, | |
f118420b | 414 | .mmap = sh_wdt_mmap, |
1da177e4 LT |
415 | }; |
416 | ||
70b814ec | 417 | static const struct watchdog_info sh_wdt_info = { |
e4c2cfee PM |
418 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | |
419 | WDIOF_MAGICCLOSE, | |
1da177e4 LT |
420 | .firmware_version = 1, |
421 | .identity = "SH WDT", | |
422 | }; | |
423 | ||
424 | static struct notifier_block sh_wdt_notifier = { | |
425 | .notifier_call = sh_wdt_notify_sys, | |
426 | }; | |
427 | ||
428 | static struct miscdevice sh_wdt_miscdev = { | |
429 | .minor = WATCHDOG_MINOR, | |
430 | .name = "watchdog", | |
431 | .fops = &sh_wdt_fops, | |
432 | }; | |
433 | ||
434 | /** | |
435 | * sh_wdt_init - Initialize module | |
1da177e4 LT |
436 | * Registers the device and notifier handler. Actual device |
437 | * initialization is handled by sh_wdt_open(). | |
438 | */ | |
439 | static int __init sh_wdt_init(void) | |
440 | { | |
441 | int rc; | |
442 | ||
70b814ec | 443 | if (clock_division_ratio < 0x5 || clock_division_ratio > 0x7) { |
1da177e4 | 444 | clock_division_ratio = WTCSR_CKS_4096; |
70b814ec AC |
445 | printk(KERN_INFO PFX |
446 | "clock_division_ratio value must be 0x5<=x<=0x7, using %d\n", | |
447 | clock_division_ratio); | |
1da177e4 LT |
448 | } |
449 | ||
e4c2cfee PM |
450 | rc = sh_wdt_set_heartbeat(heartbeat); |
451 | if (unlikely(rc)) { | |
1da177e4 | 452 | heartbeat = WATCHDOG_HEARTBEAT; |
70b814ec AC |
453 | printk(KERN_INFO PFX |
454 | "heartbeat value must be 1<=x<=3600, using %d\n", | |
455 | heartbeat); | |
1da177e4 LT |
456 | } |
457 | ||
1da177e4 | 458 | rc = register_reboot_notifier(&sh_wdt_notifier); |
e4c2cfee | 459 | if (unlikely(rc)) { |
70b814ec AC |
460 | printk(KERN_ERR PFX |
461 | "Can't register reboot notifier (err=%d)\n", rc); | |
1da177e4 LT |
462 | return rc; |
463 | } | |
464 | ||
465 | rc = misc_register(&sh_wdt_miscdev); | |
e4c2cfee | 466 | if (unlikely(rc)) { |
70b814ec AC |
467 | printk(KERN_ERR PFX |
468 | "Can't register miscdev on minor=%d (err=%d)\n", | |
469 | sh_wdt_miscdev.minor, rc); | |
1da177e4 LT |
470 | unregister_reboot_notifier(&sh_wdt_notifier); |
471 | return rc; | |
472 | } | |
473 | ||
474 | printk(KERN_INFO PFX "initialized. heartbeat=%d sec (nowayout=%d)\n", | |
475 | heartbeat, nowayout); | |
476 | ||
477 | return 0; | |
478 | } | |
479 | ||
480 | /** | |
481 | * sh_wdt_exit - Deinitialize module | |
1da177e4 LT |
482 | * Unregisters the device and notifier handler. Actual device |
483 | * deinitialization is handled by sh_wdt_close(). | |
484 | */ | |
485 | static void __exit sh_wdt_exit(void) | |
486 | { | |
487 | misc_deregister(&sh_wdt_miscdev); | |
488 | unregister_reboot_notifier(&sh_wdt_notifier); | |
489 | } | |
490 | ||
491 | MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); | |
492 | MODULE_DESCRIPTION("SuperH watchdog driver"); | |
493 | MODULE_LICENSE("GPL"); | |
494 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
495 | ||
496 | module_param(clock_division_ratio, int, 0); | |
a77dba7e WVS |
497 | MODULE_PARM_DESC(clock_division_ratio, |
498 | "Clock division ratio. Valid ranges are from 0x5 (1.31ms) " | |
499 | "to 0x7 (5.25ms). (default=" __MODULE_STRING(clock_division_ratio) ")"); | |
1da177e4 LT |
500 | |
501 | module_param(heartbeat, int, 0); | |
70b814ec AC |
502 | MODULE_PARM_DESC(heartbeat, |
503 | "Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default=" | |
504 | __MODULE_STRING(WATCHDOG_HEARTBEAT) ")"); | |
1da177e4 LT |
505 | |
506 | module_param(nowayout, int, 0); | |
70b814ec AC |
507 | MODULE_PARM_DESC(nowayout, |
508 | "Watchdog cannot be stopped once started (default=" | |
509 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
1da177e4 LT |
510 | |
511 | module_init(sh_wdt_init); | |
512 | module_exit(sh_wdt_exit); |