1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Kontron PLD watchdog driver |
4 | * |
5 | * Copyright (c) 2010-2013 Kontron Europe GmbH |
6 | * Author: Michael Brunner <michael.brunner@kontron.com> |
7 | * |
8 | * Note: From the PLD watchdog point of view timeout and pretimeout are |
9 | * defined differently than in the kernel. |
10 | * First the pretimeout stage runs out before the timeout stage gets |
11 | * active. |
12 | * |
13 | * Kernel/API: P-----| pretimeout |
14 | * |-----------------------T timeout |
15 | * Watchdog: |-----------------P pretimeout_stage |
16 | * |-----T timeout_stage |
17 | */ |
18 | |
19 | #include <linux/module.h> |
20 | #include <linux/moduleparam.h> |
21 | #include <linux/uaccess.h> |
22 | #include <linux/watchdog.h> |
23 | #include <linux/platform_device.h> |
24 | #include <linux/mfd/kempld.h> |
25 | |
26 | #define KEMPLD_WDT_STAGE_TIMEOUT(x) (0x1b + (x) * 4) |
27 | #define KEMPLD_WDT_STAGE_CFG(x) (0x18 + (x)) |
28 | #define STAGE_CFG_GET_PRESCALER(x) (((x) & 0x30) >> 4) |
29 | #define STAGE_CFG_SET_PRESCALER(x) (((x) & 0x3) << 4) |
30 | #define STAGE_CFG_PRESCALER_MASK 0x30 |
31 | #define STAGE_CFG_ACTION_MASK 0x7 |
32 | #define STAGE_CFG_ASSERT (1 << 3) |
33 | |
34 | #define KEMPLD_WDT_MAX_STAGES 2 |
35 | #define KEMPLD_WDT_KICK 0x16 |
36 | #define KEMPLD_WDT_CFG 0x17 |
37 | #define KEMPLD_WDT_CFG_ENABLE 0x10 |
38 | #define KEMPLD_WDT_CFG_ENABLE_LOCK 0x8 |
39 | #define KEMPLD_WDT_CFG_GLOBAL_LOCK 0x80 |
40 | |
41 | enum { |
42 | ACTION_NONE = 0, |
43 | ACTION_RESET, |
44 | ACTION_NMI, |
45 | ACTION_SMI, |
46 | ACTION_SCI, |
47 | ACTION_DELAY, |
48 | }; |
49 | |
50 | enum { |
51 | STAGE_TIMEOUT = 0, |
52 | STAGE_PRETIMEOUT, |
53 | }; |
54 | |
55 | enum { |
56 | PRESCALER_21 = 0, |
57 | PRESCALER_17, |
58 | PRESCALER_12, |
59 | }; |
60 | |
61 | static const u32 kempld_prescaler[] = { |
62 | [PRESCALER_21] = (1 << 21) - 1, |
63 | [PRESCALER_17] = (1 << 17) - 1, |
64 | [PRESCALER_12] = (1 << 12) - 1, |
65 | 0, |
66 | }; |
67 | |
68 | struct kempld_wdt_stage { |
69 | unsigned int id; |
70 | u32 mask; |
71 | }; |
72 | |
73 | struct kempld_wdt_data { |
74 | struct kempld_device_data *pld; |
75 | struct watchdog_device wdd; |
76 | unsigned int pretimeout; |
77 | struct kempld_wdt_stage stage[KEMPLD_WDT_MAX_STAGES]; |
78 | u8 pm_status_store; |
79 | }; |
80 | |
81 | #define DEFAULT_TIMEOUT 30 /* seconds */ |
82 | #define DEFAULT_PRETIMEOUT 0 |
83 | |
84 | static unsigned int timeout = DEFAULT_TIMEOUT; |
85 | module_param(timeout, uint, 0); |
86 | MODULE_PARM_DESC(timeout, |
87 | "Watchdog timeout in seconds. (>=0, default=" |
88 | __MODULE_STRING(DEFAULT_TIMEOUT) ")" ); |
89 | |
90 | static unsigned int pretimeout = DEFAULT_PRETIMEOUT; |
91 | module_param(pretimeout, uint, 0); |
92 | MODULE_PARM_DESC(pretimeout, |
93 | "Watchdog pretimeout in seconds. (>=0, default=" |
94 | __MODULE_STRING(DEFAULT_PRETIMEOUT) ")" ); |
95 | |
96 | static bool nowayout = WATCHDOG_NOWAYOUT; |
97 | module_param(nowayout, bool, 0); |
98 | MODULE_PARM_DESC(nowayout, |
99 | "Watchdog cannot be stopped once started (default=" |
100 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")" ); |
101 | |
102 | static int kempld_wdt_set_stage_action(struct kempld_wdt_data *wdt_data, |
103 | struct kempld_wdt_stage *stage, |
104 | u8 action) |
105 | { |
106 | struct kempld_device_data *pld = wdt_data->pld; |
107 | u8 stage_cfg; |
108 | |
109 | if (!stage || !stage->mask) |
110 | return -EINVAL; |
111 | |
112 | kempld_get_mutex(pld); |
113 | stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id)); |
114 | stage_cfg &= ~STAGE_CFG_ACTION_MASK; |
115 | stage_cfg |= (action & STAGE_CFG_ACTION_MASK); |
116 | |
117 | if (action == ACTION_RESET) |
118 | stage_cfg |= STAGE_CFG_ASSERT; |
119 | else |
120 | stage_cfg &= ~STAGE_CFG_ASSERT; |
121 | |
122 | kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), data: stage_cfg); |
123 | kempld_release_mutex(pld); |
124 | |
125 | return 0; |
126 | } |
127 | |
128 | static int kempld_wdt_set_stage_timeout(struct kempld_wdt_data *wdt_data, |
129 | struct kempld_wdt_stage *stage, |
130 | unsigned int timeout) |
131 | { |
132 | struct kempld_device_data *pld = wdt_data->pld; |
133 | u32 prescaler; |
134 | u64 stage_timeout64; |
135 | u32 stage_timeout; |
136 | u32 remainder; |
137 | u8 stage_cfg; |
138 | |
139 | prescaler = kempld_prescaler[PRESCALER_21]; |
140 | |
141 | if (!stage) |
142 | return -EINVAL; |
143 | |
144 | stage_timeout64 = (u64)timeout * pld->pld_clock; |
145 | remainder = do_div(stage_timeout64, prescaler); |
146 | if (remainder) |
147 | stage_timeout64++; |
148 | |
149 | if (stage_timeout64 > stage->mask) |
150 | return -EINVAL; |
151 | |
152 | stage_timeout = stage_timeout64 & stage->mask; |
153 | |
154 | kempld_get_mutex(pld); |
155 | stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id)); |
156 | stage_cfg &= ~STAGE_CFG_PRESCALER_MASK; |
157 | stage_cfg |= STAGE_CFG_SET_PRESCALER(PRESCALER_21); |
158 | kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), data: stage_cfg); |
159 | kempld_write32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id), |
160 | data: stage_timeout); |
161 | kempld_release_mutex(pld); |
162 | |
163 | return 0; |
164 | } |
165 | |
166 | /* |
167 | * kempld_get_mutex must be called prior to calling this function. |
168 | */ |
169 | static unsigned int kempld_wdt_get_timeout(struct kempld_wdt_data *wdt_data, |
170 | struct kempld_wdt_stage *stage) |
171 | { |
172 | struct kempld_device_data *pld = wdt_data->pld; |
173 | unsigned int timeout; |
174 | u64 stage_timeout; |
175 | u32 prescaler; |
176 | u32 remainder; |
177 | u8 stage_cfg; |
178 | |
179 | if (!stage->mask) |
180 | return 0; |
181 | |
182 | stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id)); |
183 | stage_timeout = kempld_read32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id)); |
184 | prescaler = kempld_prescaler[STAGE_CFG_GET_PRESCALER(stage_cfg)]; |
185 | |
186 | stage_timeout = (stage_timeout & stage->mask) * prescaler; |
187 | remainder = do_div(stage_timeout, pld->pld_clock); |
188 | if (remainder) |
189 | stage_timeout++; |
190 | |
191 | timeout = stage_timeout; |
192 | WARN_ON_ONCE(timeout != stage_timeout); |
193 | |
194 | return timeout; |
195 | } |
196 | |
197 | static int kempld_wdt_set_timeout(struct watchdog_device *wdd, |
198 | unsigned int timeout) |
199 | { |
200 | struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd); |
201 | struct kempld_wdt_stage *pretimeout_stage; |
202 | struct kempld_wdt_stage *timeout_stage; |
203 | int ret; |
204 | |
205 | timeout_stage = &wdt_data->stage[STAGE_TIMEOUT]; |
206 | pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT]; |
207 | |
208 | if (pretimeout_stage->mask && wdt_data->pretimeout > 0) |
209 | timeout = wdt_data->pretimeout; |
210 | |
211 | ret = kempld_wdt_set_stage_action(wdt_data, stage: timeout_stage, |
212 | action: ACTION_RESET); |
213 | if (ret) |
214 | return ret; |
215 | ret = kempld_wdt_set_stage_timeout(wdt_data, stage: timeout_stage, |
216 | timeout); |
217 | if (ret) |
218 | return ret; |
219 | |
220 | wdd->timeout = timeout; |
221 | return 0; |
222 | } |
223 | |
224 | static int kempld_wdt_set_pretimeout(struct watchdog_device *wdd, |
225 | unsigned int pretimeout) |
226 | { |
227 | struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd); |
228 | struct kempld_wdt_stage *pretimeout_stage; |
229 | u8 action = ACTION_NONE; |
230 | int ret; |
231 | |
232 | pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT]; |
233 | |
234 | if (!pretimeout_stage->mask) |
235 | return -ENXIO; |
236 | |
237 | if (pretimeout > wdd->timeout) |
238 | return -EINVAL; |
239 | |
240 | if (pretimeout > 0) |
241 | action = ACTION_NMI; |
242 | |
243 | ret = kempld_wdt_set_stage_action(wdt_data, stage: pretimeout_stage, |
244 | action); |
245 | if (ret) |
246 | return ret; |
247 | ret = kempld_wdt_set_stage_timeout(wdt_data, stage: pretimeout_stage, |
248 | timeout: wdd->timeout - pretimeout); |
249 | if (ret) |
250 | return ret; |
251 | |
252 | wdt_data->pretimeout = pretimeout; |
253 | return 0; |
254 | } |
255 | |
256 | static void kempld_wdt_update_timeouts(struct kempld_wdt_data *wdt_data) |
257 | { |
258 | struct kempld_device_data *pld = wdt_data->pld; |
259 | struct kempld_wdt_stage *pretimeout_stage; |
260 | struct kempld_wdt_stage *timeout_stage; |
261 | unsigned int pretimeout, timeout; |
262 | |
263 | pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT]; |
264 | timeout_stage = &wdt_data->stage[STAGE_TIMEOUT]; |
265 | |
266 | kempld_get_mutex(pld); |
267 | pretimeout = kempld_wdt_get_timeout(wdt_data, stage: pretimeout_stage); |
268 | timeout = kempld_wdt_get_timeout(wdt_data, stage: timeout_stage); |
269 | kempld_release_mutex(pld); |
270 | |
271 | if (pretimeout) |
272 | wdt_data->pretimeout = timeout; |
273 | else |
274 | wdt_data->pretimeout = 0; |
275 | |
276 | wdt_data->wdd.timeout = pretimeout + timeout; |
277 | } |
278 | |
279 | static int kempld_wdt_start(struct watchdog_device *wdd) |
280 | { |
281 | struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd); |
282 | struct kempld_device_data *pld = wdt_data->pld; |
283 | u8 status; |
284 | int ret; |
285 | |
286 | ret = kempld_wdt_set_timeout(wdd, timeout: wdd->timeout); |
287 | if (ret) |
288 | return ret; |
289 | |
290 | kempld_get_mutex(pld); |
291 | status = kempld_read8(pld, KEMPLD_WDT_CFG); |
292 | status |= KEMPLD_WDT_CFG_ENABLE; |
293 | kempld_write8(pld, KEMPLD_WDT_CFG, data: status); |
294 | status = kempld_read8(pld, KEMPLD_WDT_CFG); |
295 | kempld_release_mutex(pld); |
296 | |
297 | /* Check if the watchdog was enabled */ |
298 | if (!(status & KEMPLD_WDT_CFG_ENABLE)) |
299 | return -EACCES; |
300 | |
301 | return 0; |
302 | } |
303 | |
304 | static int kempld_wdt_stop(struct watchdog_device *wdd) |
305 | { |
306 | struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd); |
307 | struct kempld_device_data *pld = wdt_data->pld; |
308 | u8 status; |
309 | |
310 | kempld_get_mutex(pld); |
311 | status = kempld_read8(pld, KEMPLD_WDT_CFG); |
312 | status &= ~KEMPLD_WDT_CFG_ENABLE; |
313 | kempld_write8(pld, KEMPLD_WDT_CFG, data: status); |
314 | status = kempld_read8(pld, KEMPLD_WDT_CFG); |
315 | kempld_release_mutex(pld); |
316 | |
317 | /* Check if the watchdog was disabled */ |
318 | if (status & KEMPLD_WDT_CFG_ENABLE) |
319 | return -EACCES; |
320 | |
321 | return 0; |
322 | } |
323 | |
324 | static int kempld_wdt_keepalive(struct watchdog_device *wdd) |
325 | { |
326 | struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd); |
327 | struct kempld_device_data *pld = wdt_data->pld; |
328 | |
329 | kempld_get_mutex(pld); |
330 | kempld_write8(pld, KEMPLD_WDT_KICK, data: 'K'); |
331 | kempld_release_mutex(pld); |
332 | |
333 | return 0; |
334 | } |
335 | |
336 | static long kempld_wdt_ioctl(struct watchdog_device *wdd, unsigned int cmd, |
337 | unsigned long arg) |
338 | { |
339 | struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd); |
340 | void __user *argp = (void __user *)arg; |
341 | int ret = -ENOIOCTLCMD; |
342 | int __user *p = argp; |
343 | int new_value; |
344 | |
345 | switch (cmd) { |
346 | case WDIOC_SETPRETIMEOUT: |
347 | if (get_user(new_value, p)) |
348 | return -EFAULT; |
349 | ret = kempld_wdt_set_pretimeout(wdd, pretimeout: new_value); |
350 | if (ret) |
351 | return ret; |
352 | ret = kempld_wdt_keepalive(wdd); |
353 | break; |
354 | case WDIOC_GETPRETIMEOUT: |
355 | ret = put_user(wdt_data->pretimeout, (int __user *)arg); |
356 | break; |
357 | } |
358 | |
359 | return ret; |
360 | } |
361 | |
362 | static int kempld_wdt_probe_stages(struct watchdog_device *wdd) |
363 | { |
364 | struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd); |
365 | struct kempld_device_data *pld = wdt_data->pld; |
366 | struct kempld_wdt_stage *pretimeout_stage; |
367 | struct kempld_wdt_stage *timeout_stage; |
368 | u8 index, data, data_orig; |
369 | u32 mask; |
370 | int i, j; |
371 | |
372 | pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT]; |
373 | timeout_stage = &wdt_data->stage[STAGE_TIMEOUT]; |
374 | |
375 | pretimeout_stage->mask = 0; |
376 | timeout_stage->mask = 0; |
377 | |
378 | for (i = 0; i < 3; i++) { |
379 | index = KEMPLD_WDT_STAGE_TIMEOUT(i); |
380 | mask = 0; |
381 | |
382 | kempld_get_mutex(pld); |
383 | /* Probe each byte individually. */ |
384 | for (j = 0; j < 4; j++) { |
385 | data_orig = kempld_read8(pld, index: index + j); |
386 | kempld_write8(pld, index: index + j, data: 0x00); |
387 | data = kempld_read8(pld, index: index + j); |
388 | /* A failed write means this byte is reserved */ |
389 | if (data != 0x00) |
390 | break; |
391 | kempld_write8(pld, index: index + j, data: data_orig); |
392 | mask |= 0xff << (j * 8); |
393 | } |
394 | kempld_release_mutex(pld); |
395 | |
396 | /* Assign available stages to timeout and pretimeout */ |
397 | if (!timeout_stage->mask) { |
398 | timeout_stage->mask = mask; |
399 | timeout_stage->id = i; |
400 | } else { |
401 | if (pld->feature_mask & KEMPLD_FEATURE_BIT_NMI) { |
402 | pretimeout_stage->mask = timeout_stage->mask; |
403 | timeout_stage->mask = mask; |
404 | pretimeout_stage->id = timeout_stage->id; |
405 | timeout_stage->id = i; |
406 | } |
407 | break; |
408 | } |
409 | } |
410 | |
411 | if (!timeout_stage->mask) |
412 | return -ENODEV; |
413 | |
414 | return 0; |
415 | } |
416 | |
417 | static const struct watchdog_info kempld_wdt_info = { |
418 | .identity = "KEMPLD Watchdog" , |
419 | .options = WDIOF_SETTIMEOUT | |
420 | WDIOF_KEEPALIVEPING | |
421 | WDIOF_MAGICCLOSE | |
422 | WDIOF_PRETIMEOUT |
423 | }; |
424 | |
425 | static const struct watchdog_ops kempld_wdt_ops = { |
426 | .owner = THIS_MODULE, |
427 | .start = kempld_wdt_start, |
428 | .stop = kempld_wdt_stop, |
429 | .ping = kempld_wdt_keepalive, |
430 | .set_timeout = kempld_wdt_set_timeout, |
431 | .ioctl = kempld_wdt_ioctl, |
432 | }; |
433 | |
434 | static int kempld_wdt_probe(struct platform_device *pdev) |
435 | { |
436 | struct kempld_device_data *pld = dev_get_drvdata(dev: pdev->dev.parent); |
437 | struct kempld_wdt_data *wdt_data; |
438 | struct device *dev = &pdev->dev; |
439 | struct watchdog_device *wdd; |
440 | u8 status; |
441 | int ret = 0; |
442 | |
443 | wdt_data = devm_kzalloc(dev, size: sizeof(*wdt_data), GFP_KERNEL); |
444 | if (!wdt_data) |
445 | return -ENOMEM; |
446 | |
447 | wdt_data->pld = pld; |
448 | wdd = &wdt_data->wdd; |
449 | wdd->parent = dev; |
450 | |
451 | kempld_get_mutex(pld); |
452 | status = kempld_read8(pld, KEMPLD_WDT_CFG); |
453 | kempld_release_mutex(pld); |
454 | |
455 | /* Enable nowayout if watchdog is already locked */ |
456 | if (status & (KEMPLD_WDT_CFG_ENABLE_LOCK | |
457 | KEMPLD_WDT_CFG_GLOBAL_LOCK)) { |
458 | if (!nowayout) |
459 | dev_warn(dev, |
460 | "Forcing nowayout - watchdog lock enabled!\n" ); |
461 | nowayout = true; |
462 | } |
463 | |
464 | wdd->info = &kempld_wdt_info; |
465 | wdd->ops = &kempld_wdt_ops; |
466 | |
467 | watchdog_set_drvdata(wdd, data: wdt_data); |
468 | watchdog_set_nowayout(wdd, nowayout); |
469 | |
470 | ret = kempld_wdt_probe_stages(wdd); |
471 | if (ret) |
472 | return ret; |
473 | |
474 | kempld_wdt_set_timeout(wdd, timeout); |
475 | kempld_wdt_set_pretimeout(wdd, pretimeout); |
476 | |
477 | /* Check if watchdog is already enabled */ |
478 | if (status & KEMPLD_WDT_CFG_ENABLE) { |
479 | /* Get current watchdog settings */ |
480 | kempld_wdt_update_timeouts(wdt_data); |
481 | dev_info(dev, "Watchdog was already enabled\n" ); |
482 | } |
483 | |
484 | platform_set_drvdata(pdev, data: wdt_data); |
485 | watchdog_stop_on_reboot(wdd); |
486 | watchdog_stop_on_unregister(wdd); |
487 | ret = devm_watchdog_register_device(dev, wdd); |
488 | if (ret) |
489 | return ret; |
490 | |
491 | dev_info(dev, "Watchdog registered with %ds timeout\n" , wdd->timeout); |
492 | |
493 | return 0; |
494 | } |
495 | |
496 | /* Disable watchdog if it is active during suspend */ |
497 | static int kempld_wdt_suspend(struct platform_device *pdev, |
498 | pm_message_t message) |
499 | { |
500 | struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev); |
501 | struct kempld_device_data *pld = wdt_data->pld; |
502 | struct watchdog_device *wdd = &wdt_data->wdd; |
503 | |
504 | kempld_get_mutex(pld); |
505 | wdt_data->pm_status_store = kempld_read8(pld, KEMPLD_WDT_CFG); |
506 | kempld_release_mutex(pld); |
507 | |
508 | kempld_wdt_update_timeouts(wdt_data); |
509 | |
510 | if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE) |
511 | return kempld_wdt_stop(wdd); |
512 | |
513 | return 0; |
514 | } |
515 | |
516 | /* Enable watchdog and configure it if necessary */ |
517 | static int kempld_wdt_resume(struct platform_device *pdev) |
518 | { |
519 | struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev); |
520 | struct watchdog_device *wdd = &wdt_data->wdd; |
521 | |
522 | /* |
523 | * If watchdog was stopped before suspend be sure it gets disabled |
524 | * again, for the case BIOS has enabled it during resume |
525 | */ |
526 | if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE) |
527 | return kempld_wdt_start(wdd); |
528 | else |
529 | return kempld_wdt_stop(wdd); |
530 | } |
531 | |
532 | static struct platform_driver kempld_wdt_driver = { |
533 | .driver = { |
534 | .name = "kempld-wdt" , |
535 | }, |
536 | .probe = kempld_wdt_probe, |
537 | .suspend = pm_ptr(kempld_wdt_suspend), |
538 | .resume = pm_ptr(kempld_wdt_resume), |
539 | }; |
540 | |
541 | module_platform_driver(kempld_wdt_driver); |
542 | |
543 | MODULE_DESCRIPTION("KEM PLD Watchdog Driver" ); |
544 | MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>" ); |
545 | MODULE_LICENSE("GPL" ); |
546 | |