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1e6d320f BW |
1 | /* |
2 | * Blackfin On-Chip Watchdog Driver | |
3 | * Supports BF53[123]/BF53[467]/BF54[2489]/BF561 | |
4 | * | |
5 | * Originally based on softdog.c | |
6 | * Copyright 2006-2007 Analog Devices Inc. | |
7 | * Copyright 2006-2007 Michele d'Amico | |
8 | * Copyright 1996 Alan Cox <alan@redhat.com> | |
9 | * | |
10 | * Enter bugs at http://blackfin.uclinux.org/ | |
11 | * | |
12 | * Licensed under the GPL-2 or later. | |
13 | */ | |
14 | ||
15 | #include <linux/platform_device.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/moduleparam.h> | |
18 | #include <linux/types.h> | |
19 | #include <linux/timer.h> | |
20 | #include <linux/miscdevice.h> | |
21 | #include <linux/watchdog.h> | |
22 | #include <linux/fs.h> | |
23 | #include <linux/notifier.h> | |
24 | #include <linux/reboot.h> | |
25 | #include <linux/init.h> | |
26 | #include <linux/interrupt.h> | |
27 | #include <asm/blackfin.h> | |
9a5f50d3 | 28 | #include <linux/uaccess.h> |
1e6d320f BW |
29 | |
30 | #define stamp(fmt, args...) pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args) | |
31 | #define stampit() stamp("here i am") | |
93539b19 MF |
32 | #define pr_devinit(fmt, args...) ({ static const __devinitconst char __fmt[] = fmt; printk(__fmt, ## args); }) |
33 | #define pr_init(fmt, args...) ({ static const __initconst char __fmt[] = fmt; printk(__fmt, ## args); }) | |
1e6d320f BW |
34 | |
35 | #define WATCHDOG_NAME "bfin-wdt" | |
36 | #define PFX WATCHDOG_NAME ": " | |
37 | ||
38 | /* The BF561 has two watchdogs (one per core), but since Linux | |
39 | * only runs on core A, we'll just work with that one. | |
40 | */ | |
41 | #ifdef BF561_FAMILY | |
42 | # define bfin_read_WDOG_CTL() bfin_read_WDOGA_CTL() | |
43 | # define bfin_read_WDOG_CNT() bfin_read_WDOGA_CNT() | |
44 | # define bfin_read_WDOG_STAT() bfin_read_WDOGA_STAT() | |
45 | # define bfin_write_WDOG_CTL(x) bfin_write_WDOGA_CTL(x) | |
46 | # define bfin_write_WDOG_CNT(x) bfin_write_WDOGA_CNT(x) | |
47 | # define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x) | |
48 | #endif | |
49 | ||
50 | /* Bit in SWRST that indicates boot caused by watchdog */ | |
51 | #define SWRST_RESET_WDOG 0x4000 | |
52 | ||
53 | /* Bit in WDOG_CTL that indicates watchdog has expired (WDR0) */ | |
54 | #define WDOG_EXPIRED 0x8000 | |
55 | ||
56 | /* Masks for WDEV field in WDOG_CTL register */ | |
57 | #define ICTL_RESET 0x0 | |
58 | #define ICTL_NMI 0x2 | |
59 | #define ICTL_GPI 0x4 | |
60 | #define ICTL_NONE 0x6 | |
61 | #define ICTL_MASK 0x6 | |
62 | ||
63 | /* Masks for WDEN field in WDOG_CTL register */ | |
64 | #define WDEN_MASK 0x0FF0 | |
65 | #define WDEN_ENABLE 0x0000 | |
66 | #define WDEN_DISABLE 0x0AD0 | |
67 | ||
68 | /* some defaults */ | |
69 | #define WATCHDOG_TIMEOUT 20 | |
70 | ||
71 | static unsigned int timeout = WATCHDOG_TIMEOUT; | |
72 | static int nowayout = WATCHDOG_NOWAYOUT; | |
73 | static struct watchdog_info bfin_wdt_info; | |
74 | static unsigned long open_check; | |
75 | static char expect_close; | |
bf6350a3 | 76 | static DEFINE_SPINLOCK(bfin_wdt_spinlock); |
1e6d320f BW |
77 | |
78 | /** | |
79 | * bfin_wdt_keepalive - Keep the Userspace Watchdog Alive | |
80 | * | |
81 | * The Userspace watchdog got a KeepAlive: schedule the next timeout. | |
82 | */ | |
83 | static int bfin_wdt_keepalive(void) | |
84 | { | |
85 | stampit(); | |
86 | bfin_write_WDOG_STAT(0); | |
87 | return 0; | |
88 | } | |
89 | ||
90 | /** | |
91 | * bfin_wdt_stop - Stop the Watchdog | |
92 | * | |
93 | * Stops the on-chip watchdog. | |
94 | */ | |
95 | static int bfin_wdt_stop(void) | |
96 | { | |
97 | stampit(); | |
98 | bfin_write_WDOG_CTL(WDEN_DISABLE); | |
99 | return 0; | |
100 | } | |
101 | ||
102 | /** | |
103 | * bfin_wdt_start - Start the Watchdog | |
104 | * | |
105 | * Starts the on-chip watchdog. Automatically loads WDOG_CNT | |
106 | * into WDOG_STAT for us. | |
107 | */ | |
108 | static int bfin_wdt_start(void) | |
109 | { | |
110 | stampit(); | |
111 | bfin_write_WDOG_CTL(WDEN_ENABLE | ICTL_RESET); | |
112 | return 0; | |
113 | } | |
114 | ||
115 | /** | |
116 | * bfin_wdt_running - Check Watchdog status | |
117 | * | |
118 | * See if the watchdog is running. | |
119 | */ | |
120 | static int bfin_wdt_running(void) | |
121 | { | |
122 | stampit(); | |
123 | return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE); | |
124 | } | |
125 | ||
126 | /** | |
127 | * bfin_wdt_set_timeout - Set the Userspace Watchdog timeout | |
128 | * @t: new timeout value (in seconds) | |
129 | * | |
130 | * Translate the specified timeout in seconds into System Clock | |
131 | * terms which is what the on-chip Watchdog requires. | |
132 | */ | |
133 | static int bfin_wdt_set_timeout(unsigned long t) | |
134 | { | |
135 | u32 cnt; | |
136 | unsigned long flags; | |
137 | ||
138 | stampit(); | |
139 | ||
140 | cnt = t * get_sclk(); | |
141 | if (cnt < get_sclk()) { | |
142 | printk(KERN_WARNING PFX "timeout value is too large\n"); | |
143 | return -EINVAL; | |
144 | } | |
145 | ||
146 | spin_lock_irqsave(&bfin_wdt_spinlock, flags); | |
147 | { | |
148 | int run = bfin_wdt_running(); | |
149 | bfin_wdt_stop(); | |
150 | bfin_write_WDOG_CNT(cnt); | |
9a5f50d3 AC |
151 | if (run) |
152 | bfin_wdt_start(); | |
1e6d320f BW |
153 | } |
154 | spin_unlock_irqrestore(&bfin_wdt_spinlock, flags); | |
155 | ||
156 | timeout = t; | |
157 | ||
158 | return 0; | |
159 | } | |
160 | ||
161 | /** | |
162 | * bfin_wdt_open - Open the Device | |
163 | * @inode: inode of device | |
164 | * @file: file handle of device | |
165 | * | |
166 | * Watchdog device is opened and started. | |
167 | */ | |
168 | static int bfin_wdt_open(struct inode *inode, struct file *file) | |
169 | { | |
170 | stampit(); | |
171 | ||
172 | if (test_and_set_bit(0, &open_check)) | |
173 | return -EBUSY; | |
174 | ||
175 | if (nowayout) | |
176 | __module_get(THIS_MODULE); | |
177 | ||
178 | bfin_wdt_keepalive(); | |
179 | bfin_wdt_start(); | |
180 | ||
181 | return nonseekable_open(inode, file); | |
182 | } | |
183 | ||
184 | /** | |
185 | * bfin_wdt_close - Close the Device | |
186 | * @inode: inode of device | |
187 | * @file: file handle of device | |
188 | * | |
189 | * Watchdog device is closed and stopped. | |
190 | */ | |
191 | static int bfin_wdt_release(struct inode *inode, struct file *file) | |
192 | { | |
193 | stampit(); | |
194 | ||
9a5f50d3 | 195 | if (expect_close == 42) |
1e6d320f | 196 | bfin_wdt_stop(); |
9a5f50d3 AC |
197 | else { |
198 | printk(KERN_CRIT PFX | |
199 | "Unexpected close, not stopping watchdog!\n"); | |
1e6d320f BW |
200 | bfin_wdt_keepalive(); |
201 | } | |
1e6d320f BW |
202 | expect_close = 0; |
203 | clear_bit(0, &open_check); | |
1e6d320f BW |
204 | return 0; |
205 | } | |
206 | ||
207 | /** | |
208 | * bfin_wdt_write - Write to Device | |
209 | * @file: file handle of device | |
210 | * @buf: buffer to write | |
211 | * @count: length of buffer | |
212 | * @ppos: offset | |
213 | * | |
214 | * Pings the watchdog on write. | |
215 | */ | |
216 | static ssize_t bfin_wdt_write(struct file *file, const char __user *data, | |
9a5f50d3 | 217 | size_t len, loff_t *ppos) |
1e6d320f BW |
218 | { |
219 | stampit(); | |
220 | ||
221 | if (len) { | |
222 | if (!nowayout) { | |
223 | size_t i; | |
224 | ||
225 | /* In case it was set long ago */ | |
226 | expect_close = 0; | |
227 | ||
228 | for (i = 0; i != len; i++) { | |
229 | char c; | |
230 | if (get_user(c, data + i)) | |
231 | return -EFAULT; | |
232 | if (c == 'V') | |
233 | expect_close = 42; | |
234 | } | |
235 | } | |
236 | bfin_wdt_keepalive(); | |
237 | } | |
238 | ||
239 | return len; | |
240 | } | |
241 | ||
242 | /** | |
243 | * bfin_wdt_ioctl - Query Device | |
1e6d320f BW |
244 | * @file: file handle of device |
245 | * @cmd: watchdog command | |
246 | * @arg: argument | |
247 | * | |
248 | * Query basic information from the device or ping it, as outlined by the | |
249 | * watchdog API. | |
250 | */ | |
9a5f50d3 AC |
251 | static long bfin_wdt_ioctl(struct file *file, |
252 | unsigned int cmd, unsigned long arg) | |
1e6d320f BW |
253 | { |
254 | void __user *argp = (void __user *)arg; | |
255 | int __user *p = argp; | |
256 | ||
257 | stampit(); | |
258 | ||
259 | switch (cmd) { | |
9a5f50d3 AC |
260 | case WDIOC_GETSUPPORT: |
261 | if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info))) | |
262 | return -EFAULT; | |
263 | else | |
1e6d320f | 264 | return 0; |
9a5f50d3 AC |
265 | case WDIOC_GETSTATUS: |
266 | case WDIOC_GETBOOTSTATUS: | |
267 | return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p); | |
268 | case WDIOC_KEEPALIVE: | |
269 | bfin_wdt_keepalive(); | |
270 | return 0; | |
271 | case WDIOC_SETTIMEOUT: { | |
272 | int new_timeout; | |
273 | ||
274 | if (get_user(new_timeout, p)) | |
275 | return -EFAULT; | |
276 | if (bfin_wdt_set_timeout(new_timeout)) | |
277 | return -EINVAL; | |
278 | } | |
279 | /* Fall */ | |
280 | case WDIOC_GETTIMEOUT: | |
281 | return put_user(timeout, p); | |
282 | case WDIOC_SETOPTIONS: { | |
283 | unsigned long flags; | |
284 | int options, ret = -EINVAL; | |
285 | ||
286 | if (get_user(options, p)) | |
287 | return -EFAULT; | |
288 | ||
289 | spin_lock_irqsave(&bfin_wdt_spinlock, flags); | |
290 | if (options & WDIOS_DISABLECARD) { | |
291 | bfin_wdt_stop(); | |
292 | ret = 0; | |
1e6d320f | 293 | } |
9a5f50d3 AC |
294 | if (options & WDIOS_ENABLECARD) { |
295 | bfin_wdt_start(); | |
296 | ret = 0; | |
1e6d320f | 297 | } |
9a5f50d3 AC |
298 | spin_unlock_irqrestore(&bfin_wdt_spinlock, flags); |
299 | return ret; | |
300 | } | |
301 | default: | |
302 | return -ENOTTY; | |
1e6d320f BW |
303 | } |
304 | } | |
305 | ||
306 | /** | |
307 | * bfin_wdt_notify_sys - Notifier Handler | |
308 | * @this: notifier block | |
309 | * @code: notifier event | |
310 | * @unused: unused | |
311 | * | |
312 | * Handles specific events, such as turning off the watchdog during a | |
313 | * shutdown event. | |
314 | */ | |
9a5f50d3 AC |
315 | static int bfin_wdt_notify_sys(struct notifier_block *this, |
316 | unsigned long code, void *unused) | |
1e6d320f BW |
317 | { |
318 | stampit(); | |
319 | ||
320 | if (code == SYS_DOWN || code == SYS_HALT) | |
321 | bfin_wdt_stop(); | |
322 | ||
323 | return NOTIFY_DONE; | |
324 | } | |
325 | ||
326 | #ifdef CONFIG_PM | |
327 | static int state_before_suspend; | |
328 | ||
329 | /** | |
330 | * bfin_wdt_suspend - suspend the watchdog | |
331 | * @pdev: device being suspended | |
332 | * @state: requested suspend state | |
333 | * | |
334 | * Remember if the watchdog was running and stop it. | |
335 | * TODO: is this even right? Doesn't seem to be any | |
336 | * standard in the watchdog world ... | |
337 | */ | |
338 | static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state) | |
339 | { | |
340 | stampit(); | |
341 | ||
342 | state_before_suspend = bfin_wdt_running(); | |
343 | bfin_wdt_stop(); | |
344 | ||
345 | return 0; | |
346 | } | |
347 | ||
348 | /** | |
349 | * bfin_wdt_resume - resume the watchdog | |
350 | * @pdev: device being resumed | |
351 | * | |
352 | * If the watchdog was running, turn it back on. | |
353 | */ | |
354 | static int bfin_wdt_resume(struct platform_device *pdev) | |
355 | { | |
356 | stampit(); | |
357 | ||
358 | if (state_before_suspend) { | |
359 | bfin_wdt_set_timeout(timeout); | |
360 | bfin_wdt_start(); | |
361 | } | |
362 | ||
363 | return 0; | |
364 | } | |
365 | #else | |
366 | # define bfin_wdt_suspend NULL | |
367 | # define bfin_wdt_resume NULL | |
368 | #endif | |
369 | ||
b47a166e | 370 | static const struct file_operations bfin_wdt_fops = { |
9a5f50d3 AC |
371 | .owner = THIS_MODULE, |
372 | .llseek = no_llseek, | |
373 | .write = bfin_wdt_write, | |
374 | .unlocked_ioctl = bfin_wdt_ioctl, | |
375 | .open = bfin_wdt_open, | |
376 | .release = bfin_wdt_release, | |
1e6d320f BW |
377 | }; |
378 | ||
379 | static struct miscdevice bfin_wdt_miscdev = { | |
380 | .minor = WATCHDOG_MINOR, | |
381 | .name = "watchdog", | |
382 | .fops = &bfin_wdt_fops, | |
383 | }; | |
384 | ||
385 | static struct watchdog_info bfin_wdt_info = { | |
386 | .identity = "Blackfin Watchdog", | |
387 | .options = WDIOF_SETTIMEOUT | | |
9a5f50d3 AC |
388 | WDIOF_KEEPALIVEPING | |
389 | WDIOF_MAGICCLOSE, | |
1e6d320f BW |
390 | }; |
391 | ||
392 | static struct notifier_block bfin_wdt_notifier = { | |
393 | .notifier_call = bfin_wdt_notify_sys, | |
394 | }; | |
395 | ||
396 | /** | |
93539b19 | 397 | * bfin_wdt_probe - Initialize module |
1e6d320f | 398 | * |
93539b19 | 399 | * Registers the misc device and notifier handler. Actual device |
1e6d320f BW |
400 | * initialization is handled by bfin_wdt_open(). |
401 | */ | |
93539b19 MF |
402 | static int __devinit bfin_wdt_probe(struct platform_device *pdev) |
403 | { | |
404 | int ret; | |
405 | ||
406 | ret = register_reboot_notifier(&bfin_wdt_notifier); | |
407 | if (ret) { | |
9a5f50d3 AC |
408 | pr_devinit(KERN_ERR PFX |
409 | "cannot register reboot notifier (err=%d)\n", ret); | |
93539b19 MF |
410 | return ret; |
411 | } | |
412 | ||
413 | ret = misc_register(&bfin_wdt_miscdev); | |
414 | if (ret) { | |
9a5f50d3 AC |
415 | pr_devinit(KERN_ERR PFX |
416 | "cannot register miscdev on minor=%d (err=%d)\n", | |
417 | WATCHDOG_MINOR, ret); | |
93539b19 MF |
418 | unregister_reboot_notifier(&bfin_wdt_notifier); |
419 | return ret; | |
420 | } | |
421 | ||
422 | pr_devinit(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n", | |
423 | timeout, nowayout); | |
424 | ||
425 | return 0; | |
426 | } | |
427 | ||
428 | /** | |
429 | * bfin_wdt_remove - Initialize module | |
430 | * | |
431 | * Unregisters the misc device and notifier handler. Actual device | |
432 | * deinitialization is handled by bfin_wdt_close(). | |
433 | */ | |
434 | static int __devexit bfin_wdt_remove(struct platform_device *pdev) | |
435 | { | |
436 | misc_deregister(&bfin_wdt_miscdev); | |
437 | unregister_reboot_notifier(&bfin_wdt_notifier); | |
438 | return 0; | |
439 | } | |
440 | ||
441 | static struct platform_device *bfin_wdt_device; | |
442 | ||
443 | static struct platform_driver bfin_wdt_driver = { | |
444 | .probe = bfin_wdt_probe, | |
445 | .remove = __devexit_p(bfin_wdt_remove), | |
446 | .suspend = bfin_wdt_suspend, | |
447 | .resume = bfin_wdt_resume, | |
448 | .driver = { | |
449 | .name = WATCHDOG_NAME, | |
450 | .owner = THIS_MODULE, | |
451 | }, | |
452 | }; | |
453 | ||
454 | /** | |
455 | * bfin_wdt_init - Initialize module | |
456 | * | |
457 | * Checks the module params and registers the platform device & driver. | |
458 | * Real work is in the platform probe function. | |
459 | */ | |
1e6d320f BW |
460 | static int __init bfin_wdt_init(void) |
461 | { | |
462 | int ret; | |
463 | ||
464 | stampit(); | |
465 | ||
466 | /* Check that the timeout value is within range */ | |
467 | if (bfin_wdt_set_timeout(timeout)) | |
468 | return -EINVAL; | |
469 | ||
470 | /* Since this is an on-chip device and needs no board-specific | |
471 | * resources, we'll handle all the platform device stuff here. | |
472 | */ | |
93539b19 | 473 | ret = platform_driver_register(&bfin_wdt_driver); |
1e6d320f | 474 | if (ret) { |
93539b19 | 475 | pr_init(KERN_ERR PFX "unable to register driver\n"); |
1e6d320f BW |
476 | return ret; |
477 | } | |
478 | ||
93539b19 MF |
479 | bfin_wdt_device = platform_device_register_simple(WATCHDOG_NAME, -1, NULL, 0); |
480 | if (IS_ERR(bfin_wdt_device)) { | |
481 | pr_init(KERN_ERR PFX "unable to register device\n"); | |
482 | platform_driver_unregister(&bfin_wdt_driver); | |
483 | return PTR_ERR(bfin_wdt_device); | |
1e6d320f BW |
484 | } |
485 | ||
1e6d320f BW |
486 | return 0; |
487 | } | |
488 | ||
489 | /** | |
490 | * bfin_wdt_exit - Deinitialize module | |
491 | * | |
93539b19 MF |
492 | * Back out the platform device & driver steps. Real work is in the |
493 | * platform remove function. | |
1e6d320f BW |
494 | */ |
495 | static void __exit bfin_wdt_exit(void) | |
496 | { | |
93539b19 MF |
497 | platform_device_unregister(bfin_wdt_device); |
498 | platform_driver_unregister(&bfin_wdt_driver); | |
1e6d320f BW |
499 | } |
500 | ||
501 | module_init(bfin_wdt_init); | |
502 | module_exit(bfin_wdt_exit); | |
503 | ||
504 | MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <vapier@gentoo.org>"); | |
505 | MODULE_DESCRIPTION("Blackfin Watchdog Device Driver"); | |
506 | MODULE_LICENSE("GPL"); | |
507 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
508 | ||
509 | module_param(timeout, uint, 0); | |
9a5f50d3 AC |
510 | MODULE_PARM_DESC(timeout, |
511 | "Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default=" | |
512 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
1e6d320f BW |
513 | |
514 | module_param(nowayout, int, 0); | |
9a5f50d3 AC |
515 | MODULE_PARM_DESC(nowayout, |
516 | "Watchdog cannot be stopped once started (default=" | |
517 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |