Commit | Line | Data |
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1e6d320f BW |
1 | /* |
2 | * Blackfin On-Chip Watchdog Driver | |
1e6d320f BW |
3 | * |
4 | * Originally based on softdog.c | |
3dae93ec | 5 | * Copyright 2006-2010 Analog Devices Inc. |
1e6d320f | 6 | * Copyright 2006-2007 Michele d'Amico |
29fa0586 | 7 | * Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk> |
1e6d320f BW |
8 | * |
9 | * Enter bugs at http://blackfin.uclinux.org/ | |
10 | * | |
11 | * Licensed under the GPL-2 or later. | |
12 | */ | |
13 | ||
27c766aa JP |
14 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
15 | ||
1e6d320f BW |
16 | #include <linux/platform_device.h> |
17 | #include <linux/module.h> | |
18 | #include <linux/moduleparam.h> | |
19 | #include <linux/types.h> | |
20 | #include <linux/timer.h> | |
21 | #include <linux/miscdevice.h> | |
22 | #include <linux/watchdog.h> | |
23 | #include <linux/fs.h> | |
1e6d320f BW |
24 | #include <linux/init.h> |
25 | #include <linux/interrupt.h> | |
9a5f50d3 | 26 | #include <linux/uaccess.h> |
089ab079 | 27 | #include <asm/blackfin.h> |
42bd5d49 | 28 | #include <asm/bfin_watchdog.h> |
1e6d320f | 29 | |
a77dba7e WVS |
30 | #define stamp(fmt, args...) \ |
31 | pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args) | |
1e6d320f BW |
32 | #define stampit() stamp("here i am") |
33 | ||
34 | #define WATCHDOG_NAME "bfin-wdt" | |
1e6d320f BW |
35 | |
36 | /* The BF561 has two watchdogs (one per core), but since Linux | |
37 | * only runs on core A, we'll just work with that one. | |
38 | */ | |
39 | #ifdef BF561_FAMILY | |
40 | # define bfin_read_WDOG_CTL() bfin_read_WDOGA_CTL() | |
41 | # define bfin_read_WDOG_CNT() bfin_read_WDOGA_CNT() | |
42 | # define bfin_read_WDOG_STAT() bfin_read_WDOGA_STAT() | |
43 | # define bfin_write_WDOG_CTL(x) bfin_write_WDOGA_CTL(x) | |
44 | # define bfin_write_WDOG_CNT(x) bfin_write_WDOGA_CNT(x) | |
45 | # define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x) | |
46 | #endif | |
47 | ||
1e6d320f BW |
48 | /* some defaults */ |
49 | #define WATCHDOG_TIMEOUT 20 | |
50 | ||
51 | static unsigned int timeout = WATCHDOG_TIMEOUT; | |
86a1e189 | 52 | static bool nowayout = WATCHDOG_NOWAYOUT; |
42747d71 | 53 | static const struct watchdog_info bfin_wdt_info; |
1e6d320f BW |
54 | static unsigned long open_check; |
55 | static char expect_close; | |
bf6350a3 | 56 | static DEFINE_SPINLOCK(bfin_wdt_spinlock); |
1e6d320f BW |
57 | |
58 | /** | |
59 | * bfin_wdt_keepalive - Keep the Userspace Watchdog Alive | |
60 | * | |
5f3b2756 | 61 | * The Userspace watchdog got a KeepAlive: schedule the next timeout. |
1e6d320f BW |
62 | */ |
63 | static int bfin_wdt_keepalive(void) | |
64 | { | |
65 | stampit(); | |
66 | bfin_write_WDOG_STAT(0); | |
67 | return 0; | |
68 | } | |
69 | ||
70 | /** | |
71 | * bfin_wdt_stop - Stop the Watchdog | |
72 | * | |
73 | * Stops the on-chip watchdog. | |
74 | */ | |
75 | static int bfin_wdt_stop(void) | |
76 | { | |
77 | stampit(); | |
78 | bfin_write_WDOG_CTL(WDEN_DISABLE); | |
79 | return 0; | |
80 | } | |
81 | ||
82 | /** | |
83 | * bfin_wdt_start - Start the Watchdog | |
84 | * | |
85 | * Starts the on-chip watchdog. Automatically loads WDOG_CNT | |
86 | * into WDOG_STAT for us. | |
87 | */ | |
88 | static int bfin_wdt_start(void) | |
89 | { | |
90 | stampit(); | |
91 | bfin_write_WDOG_CTL(WDEN_ENABLE | ICTL_RESET); | |
92 | return 0; | |
93 | } | |
94 | ||
95 | /** | |
96 | * bfin_wdt_running - Check Watchdog status | |
97 | * | |
98 | * See if the watchdog is running. | |
99 | */ | |
100 | static int bfin_wdt_running(void) | |
101 | { | |
102 | stampit(); | |
103 | return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE); | |
104 | } | |
105 | ||
106 | /** | |
107 | * bfin_wdt_set_timeout - Set the Userspace Watchdog timeout | |
108 | * @t: new timeout value (in seconds) | |
109 | * | |
110 | * Translate the specified timeout in seconds into System Clock | |
111 | * terms which is what the on-chip Watchdog requires. | |
112 | */ | |
113 | static int bfin_wdt_set_timeout(unsigned long t) | |
114 | { | |
3dae93ec | 115 | u32 cnt, max_t, sclk; |
1e6d320f BW |
116 | unsigned long flags; |
117 | ||
3dae93ec MF |
118 | sclk = get_sclk(); |
119 | max_t = -1 / sclk; | |
120 | cnt = t * sclk; | |
121 | stamp("maxtimeout=%us newtimeout=%lus (cnt=%#x)", max_t, t, cnt); | |
1e6d320f | 122 | |
3dae93ec | 123 | if (t > max_t) { |
27c766aa | 124 | pr_warn("timeout value is too large\n"); |
1e6d320f BW |
125 | return -EINVAL; |
126 | } | |
127 | ||
128 | spin_lock_irqsave(&bfin_wdt_spinlock, flags); | |
129 | { | |
130 | int run = bfin_wdt_running(); | |
131 | bfin_wdt_stop(); | |
132 | bfin_write_WDOG_CNT(cnt); | |
9a5f50d3 AC |
133 | if (run) |
134 | bfin_wdt_start(); | |
1e6d320f BW |
135 | } |
136 | spin_unlock_irqrestore(&bfin_wdt_spinlock, flags); | |
137 | ||
138 | timeout = t; | |
139 | ||
140 | return 0; | |
141 | } | |
142 | ||
143 | /** | |
144 | * bfin_wdt_open - Open the Device | |
145 | * @inode: inode of device | |
146 | * @file: file handle of device | |
147 | * | |
148 | * Watchdog device is opened and started. | |
149 | */ | |
150 | static int bfin_wdt_open(struct inode *inode, struct file *file) | |
151 | { | |
152 | stampit(); | |
153 | ||
154 | if (test_and_set_bit(0, &open_check)) | |
155 | return -EBUSY; | |
156 | ||
157 | if (nowayout) | |
158 | __module_get(THIS_MODULE); | |
159 | ||
160 | bfin_wdt_keepalive(); | |
161 | bfin_wdt_start(); | |
162 | ||
163 | return nonseekable_open(inode, file); | |
164 | } | |
165 | ||
166 | /** | |
167 | * bfin_wdt_close - Close the Device | |
168 | * @inode: inode of device | |
169 | * @file: file handle of device | |
170 | * | |
171 | * Watchdog device is closed and stopped. | |
172 | */ | |
173 | static int bfin_wdt_release(struct inode *inode, struct file *file) | |
174 | { | |
175 | stampit(); | |
176 | ||
9a5f50d3 | 177 | if (expect_close == 42) |
1e6d320f | 178 | bfin_wdt_stop(); |
9a5f50d3 | 179 | else { |
27c766aa | 180 | pr_crit("Unexpected close, not stopping watchdog!\n"); |
1e6d320f BW |
181 | bfin_wdt_keepalive(); |
182 | } | |
1e6d320f BW |
183 | expect_close = 0; |
184 | clear_bit(0, &open_check); | |
1e6d320f BW |
185 | return 0; |
186 | } | |
187 | ||
188 | /** | |
189 | * bfin_wdt_write - Write to Device | |
190 | * @file: file handle of device | |
191 | * @buf: buffer to write | |
192 | * @count: length of buffer | |
193 | * @ppos: offset | |
194 | * | |
195 | * Pings the watchdog on write. | |
196 | */ | |
197 | static ssize_t bfin_wdt_write(struct file *file, const char __user *data, | |
9a5f50d3 | 198 | size_t len, loff_t *ppos) |
1e6d320f BW |
199 | { |
200 | stampit(); | |
201 | ||
202 | if (len) { | |
203 | if (!nowayout) { | |
204 | size_t i; | |
205 | ||
206 | /* In case it was set long ago */ | |
207 | expect_close = 0; | |
208 | ||
209 | for (i = 0; i != len; i++) { | |
210 | char c; | |
211 | if (get_user(c, data + i)) | |
212 | return -EFAULT; | |
213 | if (c == 'V') | |
214 | expect_close = 42; | |
215 | } | |
216 | } | |
217 | bfin_wdt_keepalive(); | |
218 | } | |
219 | ||
220 | return len; | |
221 | } | |
222 | ||
223 | /** | |
224 | * bfin_wdt_ioctl - Query Device | |
1e6d320f BW |
225 | * @file: file handle of device |
226 | * @cmd: watchdog command | |
227 | * @arg: argument | |
228 | * | |
229 | * Query basic information from the device or ping it, as outlined by the | |
230 | * watchdog API. | |
231 | */ | |
9a5f50d3 AC |
232 | static long bfin_wdt_ioctl(struct file *file, |
233 | unsigned int cmd, unsigned long arg) | |
1e6d320f BW |
234 | { |
235 | void __user *argp = (void __user *)arg; | |
236 | int __user *p = argp; | |
237 | ||
238 | stampit(); | |
239 | ||
240 | switch (cmd) { | |
9a5f50d3 AC |
241 | case WDIOC_GETSUPPORT: |
242 | if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info))) | |
243 | return -EFAULT; | |
244 | else | |
1e6d320f | 245 | return 0; |
9a5f50d3 AC |
246 | case WDIOC_GETSTATUS: |
247 | case WDIOC_GETBOOTSTATUS: | |
248 | return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p); | |
9a5f50d3 AC |
249 | case WDIOC_SETOPTIONS: { |
250 | unsigned long flags; | |
251 | int options, ret = -EINVAL; | |
252 | ||
253 | if (get_user(options, p)) | |
254 | return -EFAULT; | |
255 | ||
256 | spin_lock_irqsave(&bfin_wdt_spinlock, flags); | |
257 | if (options & WDIOS_DISABLECARD) { | |
258 | bfin_wdt_stop(); | |
259 | ret = 0; | |
1e6d320f | 260 | } |
9a5f50d3 AC |
261 | if (options & WDIOS_ENABLECARD) { |
262 | bfin_wdt_start(); | |
263 | ret = 0; | |
1e6d320f | 264 | } |
9a5f50d3 AC |
265 | spin_unlock_irqrestore(&bfin_wdt_spinlock, flags); |
266 | return ret; | |
267 | } | |
0c06090c WVS |
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); | |
9a5f50d3 AC |
282 | default: |
283 | return -ENOTTY; | |
1e6d320f BW |
284 | } |
285 | } | |
286 | ||
1e6d320f BW |
287 | #ifdef CONFIG_PM |
288 | static int state_before_suspend; | |
289 | ||
290 | /** | |
291 | * bfin_wdt_suspend - suspend the watchdog | |
292 | * @pdev: device being suspended | |
293 | * @state: requested suspend state | |
294 | * | |
295 | * Remember if the watchdog was running and stop it. | |
296 | * TODO: is this even right? Doesn't seem to be any | |
297 | * standard in the watchdog world ... | |
298 | */ | |
299 | static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state) | |
300 | { | |
301 | stampit(); | |
302 | ||
303 | state_before_suspend = bfin_wdt_running(); | |
304 | bfin_wdt_stop(); | |
305 | ||
306 | return 0; | |
307 | } | |
308 | ||
309 | /** | |
310 | * bfin_wdt_resume - resume the watchdog | |
311 | * @pdev: device being resumed | |
312 | * | |
313 | * If the watchdog was running, turn it back on. | |
314 | */ | |
315 | static int bfin_wdt_resume(struct platform_device *pdev) | |
316 | { | |
317 | stampit(); | |
318 | ||
319 | if (state_before_suspend) { | |
320 | bfin_wdt_set_timeout(timeout); | |
321 | bfin_wdt_start(); | |
322 | } | |
323 | ||
324 | return 0; | |
325 | } | |
326 | #else | |
327 | # define bfin_wdt_suspend NULL | |
328 | # define bfin_wdt_resume NULL | |
329 | #endif | |
330 | ||
b47a166e | 331 | static const struct file_operations bfin_wdt_fops = { |
9a5f50d3 AC |
332 | .owner = THIS_MODULE, |
333 | .llseek = no_llseek, | |
5f3b2756 | 334 | .write = bfin_wdt_write, |
9a5f50d3 AC |
335 | .unlocked_ioctl = bfin_wdt_ioctl, |
336 | .open = bfin_wdt_open, | |
337 | .release = bfin_wdt_release, | |
1e6d320f BW |
338 | }; |
339 | ||
340 | static struct miscdevice bfin_wdt_miscdev = { | |
341 | .minor = WATCHDOG_MINOR, | |
342 | .name = "watchdog", | |
343 | .fops = &bfin_wdt_fops, | |
344 | }; | |
345 | ||
42747d71 | 346 | static const struct watchdog_info bfin_wdt_info = { |
1e6d320f BW |
347 | .identity = "Blackfin Watchdog", |
348 | .options = WDIOF_SETTIMEOUT | | |
9a5f50d3 AC |
349 | WDIOF_KEEPALIVEPING | |
350 | WDIOF_MAGICCLOSE, | |
1e6d320f BW |
351 | }; |
352 | ||
1e6d320f | 353 | /** |
93539b19 | 354 | * bfin_wdt_probe - Initialize module |
1e6d320f | 355 | * |
168b5251 | 356 | * Registers the misc device. Actual device |
1e6d320f BW |
357 | * initialization is handled by bfin_wdt_open(). |
358 | */ | |
2d991a16 | 359 | static int bfin_wdt_probe(struct platform_device *pdev) |
93539b19 MF |
360 | { |
361 | int ret; | |
362 | ||
93539b19 MF |
363 | ret = misc_register(&bfin_wdt_miscdev); |
364 | if (ret) { | |
27c766aa JP |
365 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
366 | WATCHDOG_MINOR, ret); | |
93539b19 MF |
367 | return ret; |
368 | } | |
369 | ||
27c766aa JP |
370 | pr_info("initialized: timeout=%d sec (nowayout=%d)\n", |
371 | timeout, nowayout); | |
93539b19 MF |
372 | |
373 | return 0; | |
374 | } | |
375 | ||
376 | /** | |
377 | * bfin_wdt_remove - Initialize module | |
378 | * | |
168b5251 | 379 | * Unregisters the misc device. Actual device |
93539b19 MF |
380 | * deinitialization is handled by bfin_wdt_close(). |
381 | */ | |
4b12b896 | 382 | static int bfin_wdt_remove(struct platform_device *pdev) |
93539b19 MF |
383 | { |
384 | misc_deregister(&bfin_wdt_miscdev); | |
93539b19 MF |
385 | return 0; |
386 | } | |
387 | ||
168b5251 WVS |
388 | /** |
389 | * bfin_wdt_shutdown - Soft Shutdown Handler | |
390 | * | |
391 | * Handles the soft shutdown event. | |
392 | */ | |
393 | static void bfin_wdt_shutdown(struct platform_device *pdev) | |
394 | { | |
395 | stampit(); | |
396 | ||
397 | bfin_wdt_stop(); | |
398 | } | |
399 | ||
93539b19 MF |
400 | static struct platform_device *bfin_wdt_device; |
401 | ||
402 | static struct platform_driver bfin_wdt_driver = { | |
403 | .probe = bfin_wdt_probe, | |
82268714 | 404 | .remove = bfin_wdt_remove, |
168b5251 | 405 | .shutdown = bfin_wdt_shutdown, |
93539b19 MF |
406 | .suspend = bfin_wdt_suspend, |
407 | .resume = bfin_wdt_resume, | |
408 | .driver = { | |
409 | .name = WATCHDOG_NAME, | |
410 | .owner = THIS_MODULE, | |
411 | }, | |
412 | }; | |
413 | ||
414 | /** | |
415 | * bfin_wdt_init - Initialize module | |
416 | * | |
417 | * Checks the module params and registers the platform device & driver. | |
418 | * Real work is in the platform probe function. | |
419 | */ | |
1e6d320f BW |
420 | static int __init bfin_wdt_init(void) |
421 | { | |
422 | int ret; | |
423 | ||
424 | stampit(); | |
425 | ||
426 | /* Check that the timeout value is within range */ | |
427 | if (bfin_wdt_set_timeout(timeout)) | |
428 | return -EINVAL; | |
429 | ||
430 | /* Since this is an on-chip device and needs no board-specific | |
431 | * resources, we'll handle all the platform device stuff here. | |
432 | */ | |
93539b19 | 433 | ret = platform_driver_register(&bfin_wdt_driver); |
1e6d320f | 434 | if (ret) { |
27c766aa | 435 | pr_err("unable to register driver\n"); |
1e6d320f BW |
436 | return ret; |
437 | } | |
438 | ||
a77dba7e WVS |
439 | bfin_wdt_device = platform_device_register_simple(WATCHDOG_NAME, |
440 | -1, NULL, 0); | |
93539b19 | 441 | if (IS_ERR(bfin_wdt_device)) { |
27c766aa | 442 | pr_err("unable to register device\n"); |
93539b19 MF |
443 | platform_driver_unregister(&bfin_wdt_driver); |
444 | return PTR_ERR(bfin_wdt_device); | |
1e6d320f BW |
445 | } |
446 | ||
1e6d320f BW |
447 | return 0; |
448 | } | |
449 | ||
450 | /** | |
451 | * bfin_wdt_exit - Deinitialize module | |
452 | * | |
93539b19 MF |
453 | * Back out the platform device & driver steps. Real work is in the |
454 | * platform remove function. | |
1e6d320f BW |
455 | */ |
456 | static void __exit bfin_wdt_exit(void) | |
457 | { | |
93539b19 MF |
458 | platform_device_unregister(bfin_wdt_device); |
459 | platform_driver_unregister(&bfin_wdt_driver); | |
1e6d320f BW |
460 | } |
461 | ||
462 | module_init(bfin_wdt_init); | |
463 | module_exit(bfin_wdt_exit); | |
464 | ||
465 | MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <vapier@gentoo.org>"); | |
466 | MODULE_DESCRIPTION("Blackfin Watchdog Device Driver"); | |
467 | MODULE_LICENSE("GPL"); | |
1e6d320f BW |
468 | |
469 | module_param(timeout, uint, 0); | |
9a5f50d3 AC |
470 | MODULE_PARM_DESC(timeout, |
471 | "Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default=" | |
472 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
1e6d320f | 473 | |
86a1e189 | 474 | module_param(nowayout, bool, 0); |
9a5f50d3 AC |
475 | MODULE_PARM_DESC(nowayout, |
476 | "Watchdog cannot be stopped once started (default=" | |
477 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |