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Kevin Strassere51c2882013-06-23 21:00:06 -07001/*
2 * Kontron PLD watchdog driver
3 *
4 * Copyright (c) 2010-2013 Kontron Europe GmbH
5 * Author: Michael Brunner <michael.brunner@kontron.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License 2 as published
9 * by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * Note: From the PLD watchdog point of view timeout and pretimeout are
17 * defined differently than in the kernel.
18 * First the pretimeout stage runs out before the timeout stage gets
19 * active.
20 *
21 * Kernel/API: P-----| pretimeout
22 * |-----------------------T timeout
23 * Watchdog: |-----------------P pretimeout_stage
24 * |-----T timeout_stage
25 */
26
27#include <linux/module.h>
28#include <linux/moduleparam.h>
Kevin Strassere51c2882013-06-23 21:00:06 -070029#include <linux/uaccess.h>
30#include <linux/watchdog.h>
31#include <linux/platform_device.h>
32#include <linux/mfd/kempld.h>
33
34#define KEMPLD_WDT_STAGE_TIMEOUT(x) (0x1b + (x) * 4)
35#define KEMPLD_WDT_STAGE_CFG(x) (0x18 + (x))
36#define STAGE_CFG_GET_PRESCALER(x) (((x) & 0x30) >> 4)
Jingoo Han4c4e4562013-09-23 19:16:57 +090037#define STAGE_CFG_SET_PRESCALER(x) (((x) & 0x3) << 4)
Kevin Strassere51c2882013-06-23 21:00:06 -070038#define STAGE_CFG_PRESCALER_MASK 0x30
39#define STAGE_CFG_ACTION_MASK 0x7
40#define STAGE_CFG_ASSERT (1 << 3)
41
42#define KEMPLD_WDT_MAX_STAGES 2
43#define KEMPLD_WDT_KICK 0x16
44#define KEMPLD_WDT_CFG 0x17
45#define KEMPLD_WDT_CFG_ENABLE 0x10
46#define KEMPLD_WDT_CFG_ENABLE_LOCK 0x8
47#define KEMPLD_WDT_CFG_GLOBAL_LOCK 0x80
48
49enum {
50 ACTION_NONE = 0,
51 ACTION_RESET,
52 ACTION_NMI,
53 ACTION_SMI,
54 ACTION_SCI,
55 ACTION_DELAY,
56};
57
58enum {
59 STAGE_TIMEOUT = 0,
60 STAGE_PRETIMEOUT,
61};
62
63enum {
64 PRESCALER_21 = 0,
65 PRESCALER_17,
66 PRESCALER_12,
67};
68
Jingoo Hanb3970bd2013-08-01 14:39:46 +090069static const u32 kempld_prescaler[] = {
Kevin Strassere51c2882013-06-23 21:00:06 -070070 [PRESCALER_21] = (1 << 21) - 1,
71 [PRESCALER_17] = (1 << 17) - 1,
72 [PRESCALER_12] = (1 << 12) - 1,
73 0,
74};
75
76struct kempld_wdt_stage {
77 unsigned int id;
78 u32 mask;
79};
80
81struct kempld_wdt_data {
82 struct kempld_device_data *pld;
83 struct watchdog_device wdd;
84 unsigned int pretimeout;
85 struct kempld_wdt_stage stage[KEMPLD_WDT_MAX_STAGES];
86#ifdef CONFIG_PM
87 u8 pm_status_store;
88#endif
89};
90
91#define DEFAULT_TIMEOUT 30 /* seconds */
92#define DEFAULT_PRETIMEOUT 0
93
94static unsigned int timeout = DEFAULT_TIMEOUT;
95module_param(timeout, uint, 0);
96MODULE_PARM_DESC(timeout,
97 "Watchdog timeout in seconds. (>=0, default="
98 __MODULE_STRING(DEFAULT_TIMEOUT) ")");
99
100static unsigned int pretimeout = DEFAULT_PRETIMEOUT;
101module_param(pretimeout, uint, 0);
102MODULE_PARM_DESC(pretimeout,
103 "Watchdog pretimeout in seconds. (>=0, default="
104 __MODULE_STRING(DEFAULT_PRETIMEOUT) ")");
105
106static bool nowayout = WATCHDOG_NOWAYOUT;
107module_param(nowayout, bool, 0);
108MODULE_PARM_DESC(nowayout,
109 "Watchdog cannot be stopped once started (default="
110 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
111
112static int kempld_wdt_set_stage_action(struct kempld_wdt_data *wdt_data,
113 struct kempld_wdt_stage *stage,
114 u8 action)
115{
116 struct kempld_device_data *pld = wdt_data->pld;
117 u8 stage_cfg;
118
119 if (!stage || !stage->mask)
120 return -EINVAL;
121
122 kempld_get_mutex(pld);
123 stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
124 stage_cfg &= ~STAGE_CFG_ACTION_MASK;
125 stage_cfg |= (action & STAGE_CFG_ACTION_MASK);
126
127 if (action == ACTION_RESET)
128 stage_cfg |= STAGE_CFG_ASSERT;
129 else
130 stage_cfg &= ~STAGE_CFG_ASSERT;
131
132 kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), stage_cfg);
133 kempld_release_mutex(pld);
134
135 return 0;
136}
137
138static int kempld_wdt_set_stage_timeout(struct kempld_wdt_data *wdt_data,
139 struct kempld_wdt_stage *stage,
140 unsigned int timeout)
141{
142 struct kempld_device_data *pld = wdt_data->pld;
143 u32 prescaler = kempld_prescaler[PRESCALER_21];
144 u64 stage_timeout64;
145 u32 stage_timeout;
146 u32 remainder;
147 u8 stage_cfg;
148
149 if (!stage)
150 return -EINVAL;
151
152 stage_timeout64 = (u64)timeout * pld->pld_clock;
153 remainder = do_div(stage_timeout64, prescaler);
154 if (remainder)
155 stage_timeout64++;
156
157 if (stage_timeout64 > stage->mask)
158 return -EINVAL;
159
160 stage_timeout = stage_timeout64 & stage->mask;
161
162 kempld_get_mutex(pld);
163 stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
164 stage_cfg &= ~STAGE_CFG_PRESCALER_MASK;
gundberga9e04362014-04-24 15:49:19 +0200165 stage_cfg |= STAGE_CFG_SET_PRESCALER(PRESCALER_21);
Kevin Strassere51c2882013-06-23 21:00:06 -0700166 kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), stage_cfg);
167 kempld_write32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id),
168 stage_timeout);
169 kempld_release_mutex(pld);
170
171 return 0;
172}
173
174/*
175 * kempld_get_mutex must be called prior to calling this function.
176 */
177static unsigned int kempld_wdt_get_timeout(struct kempld_wdt_data *wdt_data,
178 struct kempld_wdt_stage *stage)
179{
180 struct kempld_device_data *pld = wdt_data->pld;
181 unsigned int timeout;
182 u64 stage_timeout;
183 u32 prescaler;
184 u32 remainder;
185 u8 stage_cfg;
186
187 if (!stage->mask)
188 return 0;
189
190 stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
191 stage_timeout = kempld_read32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id));
192 prescaler = kempld_prescaler[STAGE_CFG_GET_PRESCALER(stage_cfg)];
193
194 stage_timeout = (stage_timeout & stage->mask) * prescaler;
195 remainder = do_div(stage_timeout, pld->pld_clock);
196 if (remainder)
197 stage_timeout++;
198
199 timeout = stage_timeout;
200 WARN_ON_ONCE(timeout != stage_timeout);
201
202 return timeout;
203}
204
205static int kempld_wdt_set_timeout(struct watchdog_device *wdd,
206 unsigned int timeout)
207{
208 struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
209 struct kempld_wdt_stage *pretimeout_stage;
210 struct kempld_wdt_stage *timeout_stage;
211 int ret;
212
213 timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
214 pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
215
216 if (pretimeout_stage->mask && wdt_data->pretimeout > 0)
217 timeout = wdt_data->pretimeout;
218
219 ret = kempld_wdt_set_stage_action(wdt_data, timeout_stage,
220 ACTION_RESET);
221 if (ret)
222 return ret;
223 ret = kempld_wdt_set_stage_timeout(wdt_data, timeout_stage,
224 timeout);
225 if (ret)
226 return ret;
227
228 wdd->timeout = timeout;
229 return 0;
230}
231
232static int kempld_wdt_set_pretimeout(struct watchdog_device *wdd,
233 unsigned int pretimeout)
234{
235 struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
236 struct kempld_wdt_stage *pretimeout_stage;
237 u8 action = ACTION_NONE;
238 int ret;
239
240 pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
241
242 if (!pretimeout_stage->mask)
243 return -ENXIO;
244
245 if (pretimeout > wdd->timeout)
246 return -EINVAL;
247
248 if (pretimeout > 0)
249 action = ACTION_NMI;
250
251 ret = kempld_wdt_set_stage_action(wdt_data, pretimeout_stage,
252 action);
253 if (ret)
254 return ret;
255 ret = kempld_wdt_set_stage_timeout(wdt_data, pretimeout_stage,
256 wdd->timeout - pretimeout);
257 if (ret)
258 return ret;
259
260 wdt_data->pretimeout = pretimeout;
261 return 0;
262}
263
264static void kempld_wdt_update_timeouts(struct kempld_wdt_data *wdt_data)
265{
266 struct kempld_device_data *pld = wdt_data->pld;
267 struct kempld_wdt_stage *pretimeout_stage;
268 struct kempld_wdt_stage *timeout_stage;
269 unsigned int pretimeout, timeout;
270
271 pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
272 timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
273
274 kempld_get_mutex(pld);
275 pretimeout = kempld_wdt_get_timeout(wdt_data, pretimeout_stage);
276 timeout = kempld_wdt_get_timeout(wdt_data, timeout_stage);
277 kempld_release_mutex(pld);
278
279 if (pretimeout)
280 wdt_data->pretimeout = timeout;
281 else
282 wdt_data->pretimeout = 0;
283
284 wdt_data->wdd.timeout = pretimeout + timeout;
285}
286
287static int kempld_wdt_start(struct watchdog_device *wdd)
288{
289 struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
290 struct kempld_device_data *pld = wdt_data->pld;
291 u8 status;
292 int ret;
293
294 ret = kempld_wdt_set_timeout(wdd, wdd->timeout);
295 if (ret)
296 return ret;
297
298 kempld_get_mutex(pld);
299 status = kempld_read8(pld, KEMPLD_WDT_CFG);
300 status |= KEMPLD_WDT_CFG_ENABLE;
301 kempld_write8(pld, KEMPLD_WDT_CFG, status);
302 status = kempld_read8(pld, KEMPLD_WDT_CFG);
303 kempld_release_mutex(pld);
304
305 /* Check if the watchdog was enabled */
306 if (!(status & KEMPLD_WDT_CFG_ENABLE))
307 return -EACCES;
308
309 return 0;
310}
311
312static int kempld_wdt_stop(struct watchdog_device *wdd)
313{
314 struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
315 struct kempld_device_data *pld = wdt_data->pld;
316 u8 status;
317
318 kempld_get_mutex(pld);
319 status = kempld_read8(pld, KEMPLD_WDT_CFG);
320 status &= ~KEMPLD_WDT_CFG_ENABLE;
321 kempld_write8(pld, KEMPLD_WDT_CFG, status);
322 status = kempld_read8(pld, KEMPLD_WDT_CFG);
323 kempld_release_mutex(pld);
324
325 /* Check if the watchdog was disabled */
326 if (status & KEMPLD_WDT_CFG_ENABLE)
327 return -EACCES;
328
329 return 0;
330}
331
332static int kempld_wdt_keepalive(struct watchdog_device *wdd)
333{
334 struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
335 struct kempld_device_data *pld = wdt_data->pld;
336
337 kempld_get_mutex(pld);
338 kempld_write8(pld, KEMPLD_WDT_KICK, 'K');
339 kempld_release_mutex(pld);
340
341 return 0;
342}
343
344static long kempld_wdt_ioctl(struct watchdog_device *wdd, unsigned int cmd,
345 unsigned long arg)
346{
347 struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
348 void __user *argp = (void __user *)arg;
349 int ret = -ENOIOCTLCMD;
350 int __user *p = argp;
351 int new_value;
352
353 switch (cmd) {
354 case WDIOC_SETPRETIMEOUT:
355 if (get_user(new_value, p))
356 return -EFAULT;
357 ret = kempld_wdt_set_pretimeout(wdd, new_value);
358 if (ret)
359 return ret;
360 ret = kempld_wdt_keepalive(wdd);
361 break;
362 case WDIOC_GETPRETIMEOUT:
Jingoo Hanb3970bd2013-08-01 14:39:46 +0900363 ret = put_user(wdt_data->pretimeout, (int __user *)arg);
Kevin Strassere51c2882013-06-23 21:00:06 -0700364 break;
365 }
366
367 return ret;
368}
369
370static int kempld_wdt_probe_stages(struct watchdog_device *wdd)
371{
372 struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
373 struct kempld_device_data *pld = wdt_data->pld;
374 struct kempld_wdt_stage *pretimeout_stage;
375 struct kempld_wdt_stage *timeout_stage;
376 u8 index, data, data_orig;
377 u32 mask;
378 int i, j;
379
380 pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
381 timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
382
383 pretimeout_stage->mask = 0;
384 timeout_stage->mask = 0;
385
386 for (i = 0; i < 3; i++) {
387 index = KEMPLD_WDT_STAGE_TIMEOUT(i);
388 mask = 0;
389
390 kempld_get_mutex(pld);
391 /* Probe each byte individually. */
392 for (j = 0; j < 4; j++) {
393 data_orig = kempld_read8(pld, index + j);
394 kempld_write8(pld, index + j, 0x00);
395 data = kempld_read8(pld, index + j);
396 /* A failed write means this byte is reserved */
397 if (data != 0x00)
398 break;
399 kempld_write8(pld, index + j, data_orig);
400 mask |= 0xff << (j * 8);
401 }
402 kempld_release_mutex(pld);
403
404 /* Assign available stages to timeout and pretimeout */
405 if (!timeout_stage->mask) {
406 timeout_stage->mask = mask;
407 timeout_stage->id = i;
408 } else {
409 if (pld->feature_mask & KEMPLD_FEATURE_BIT_NMI) {
410 pretimeout_stage->mask = timeout_stage->mask;
411 timeout_stage->mask = mask;
412 pretimeout_stage->id = timeout_stage->id;
413 timeout_stage->id = i;
414 }
415 break;
416 }
417 }
418
419 if (!timeout_stage->mask)
420 return -ENODEV;
421
422 return 0;
423}
424
425static struct watchdog_info kempld_wdt_info = {
426 .identity = "KEMPLD Watchdog",
427 .options = WDIOF_SETTIMEOUT |
428 WDIOF_KEEPALIVEPING |
429 WDIOF_MAGICCLOSE |
430 WDIOF_PRETIMEOUT
431};
432
433static struct watchdog_ops kempld_wdt_ops = {
434 .owner = THIS_MODULE,
435 .start = kempld_wdt_start,
436 .stop = kempld_wdt_stop,
437 .ping = kempld_wdt_keepalive,
438 .set_timeout = kempld_wdt_set_timeout,
439 .ioctl = kempld_wdt_ioctl,
440};
441
442static int kempld_wdt_probe(struct platform_device *pdev)
443{
444 struct kempld_device_data *pld = dev_get_drvdata(pdev->dev.parent);
445 struct kempld_wdt_data *wdt_data;
446 struct device *dev = &pdev->dev;
447 struct watchdog_device *wdd;
448 u8 status;
449 int ret = 0;
450
451 wdt_data = devm_kzalloc(dev, sizeof(*wdt_data), GFP_KERNEL);
452 if (!wdt_data)
453 return -ENOMEM;
454
455 wdt_data->pld = pld;
456 wdd = &wdt_data->wdd;
457 wdd->parent = dev;
458
459 kempld_get_mutex(pld);
460 status = kempld_read8(pld, KEMPLD_WDT_CFG);
461 kempld_release_mutex(pld);
462
463 /* Enable nowayout if watchdog is already locked */
464 if (status & (KEMPLD_WDT_CFG_ENABLE_LOCK |
465 KEMPLD_WDT_CFG_GLOBAL_LOCK)) {
466 if (!nowayout)
467 dev_warn(dev,
468 "Forcing nowayout - watchdog lock enabled!\n");
469 nowayout = true;
470 }
471
472 wdd->info = &kempld_wdt_info;
473 wdd->ops = &kempld_wdt_ops;
474
475 watchdog_set_drvdata(wdd, wdt_data);
476 watchdog_set_nowayout(wdd, nowayout);
477
478 ret = kempld_wdt_probe_stages(wdd);
479 if (ret)
480 return ret;
481
482 kempld_wdt_set_timeout(wdd, timeout);
483 kempld_wdt_set_pretimeout(wdd, pretimeout);
484
485 /* Check if watchdog is already enabled */
486 if (status & KEMPLD_WDT_CFG_ENABLE) {
487 /* Get current watchdog settings */
488 kempld_wdt_update_timeouts(wdt_data);
489 dev_info(dev, "Watchdog was already enabled\n");
490 }
491
492 platform_set_drvdata(pdev, wdt_data);
493 ret = watchdog_register_device(wdd);
494 if (ret)
495 return ret;
496
497 dev_info(dev, "Watchdog registered with %ds timeout\n", wdd->timeout);
498
499 return 0;
500}
501
502static void kempld_wdt_shutdown(struct platform_device *pdev)
503{
504 struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
505
506 kempld_wdt_stop(&wdt_data->wdd);
507}
508
509static int kempld_wdt_remove(struct platform_device *pdev)
510{
511 struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
512 struct watchdog_device *wdd = &wdt_data->wdd;
513 int ret = 0;
514
515 if (!nowayout)
516 ret = kempld_wdt_stop(wdd);
517 watchdog_unregister_device(wdd);
518
519 return ret;
520}
521
522#ifdef CONFIG_PM
523/* Disable watchdog if it is active during suspend */
524static int kempld_wdt_suspend(struct platform_device *pdev,
525 pm_message_t message)
526{
527 struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
528 struct kempld_device_data *pld = wdt_data->pld;
529 struct watchdog_device *wdd = &wdt_data->wdd;
530
531 kempld_get_mutex(pld);
532 wdt_data->pm_status_store = kempld_read8(pld, KEMPLD_WDT_CFG);
533 kempld_release_mutex(pld);
534
535 kempld_wdt_update_timeouts(wdt_data);
536
537 if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE)
538 return kempld_wdt_stop(wdd);
539
540 return 0;
541}
542
543/* Enable watchdog and configure it if necessary */
544static int kempld_wdt_resume(struct platform_device *pdev)
545{
546 struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
547 struct watchdog_device *wdd = &wdt_data->wdd;
548
549 /*
550 * If watchdog was stopped before suspend be sure it gets disabled
551 * again, for the case BIOS has enabled it during resume
552 */
553 if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE)
554 return kempld_wdt_start(wdd);
555 else
556 return kempld_wdt_stop(wdd);
557}
558#else
559#define kempld_wdt_suspend NULL
560#define kempld_wdt_resume NULL
561#endif
562
563static struct platform_driver kempld_wdt_driver = {
564 .driver = {
565 .name = "kempld-wdt",
Kevin Strassere51c2882013-06-23 21:00:06 -0700566 },
567 .probe = kempld_wdt_probe,
568 .remove = kempld_wdt_remove,
569 .shutdown = kempld_wdt_shutdown,
570 .suspend = kempld_wdt_suspend,
571 .resume = kempld_wdt_resume,
572};
573
574module_platform_driver(kempld_wdt_driver);
575
576MODULE_DESCRIPTION("KEM PLD Watchdog Driver");
577MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
578MODULE_LICENSE("GPL");