2 * Kontron PLD watchdog driver
4 * Copyright (c) 2010-2013 Kontron Europe GmbH
5 * Author: Michael Brunner <michael.brunner@kontron.com>
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.
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.
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
21 * Kernel/API: P-----| pretimeout
22 * |-----------------------T timeout
23 * Watchdog: |-----------------P pretimeout_stage
24 * |-----T timeout_stage
27 #include <linux/module.h>
28 #include <linux/moduleparam.h>
29 #include <linux/uaccess.h>
30 #include <linux/watchdog.h>
31 #include <linux/platform_device.h>
32 #include <linux/mfd/kempld.h>
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)
37 #define STAGE_CFG_SET_PRESCALER(x) (((x) & 0x3) << 4)
38 #define STAGE_CFG_PRESCALER_MASK 0x30
39 #define STAGE_CFG_ACTION_MASK 0x7
40 #define STAGE_CFG_ASSERT (1 << 3)
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
69 static const u32 kempld_prescaler[] = {
70 [PRESCALER_21] = (1 << 21) - 1,
71 [PRESCALER_17] = (1 << 17) - 1,
72 [PRESCALER_12] = (1 << 12) - 1,
76 struct kempld_wdt_stage {
81 struct 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];
91 #define DEFAULT_TIMEOUT 30 /* seconds */
92 #define DEFAULT_PRETIMEOUT 0
94 static unsigned int timeout = DEFAULT_TIMEOUT;
95 module_param(timeout, uint, 0);
96 MODULE_PARM_DESC(timeout,
97 "Watchdog timeout in seconds. (>=0, default="
98 __MODULE_STRING(DEFAULT_TIMEOUT) ")");
100 static unsigned int pretimeout = DEFAULT_PRETIMEOUT;
101 module_param(pretimeout, uint, 0);
102 MODULE_PARM_DESC(pretimeout,
103 "Watchdog pretimeout in seconds. (>=0, default="
104 __MODULE_STRING(DEFAULT_PRETIMEOUT) ")");
106 static bool nowayout = WATCHDOG_NOWAYOUT;
107 module_param(nowayout, bool, 0);
108 MODULE_PARM_DESC(nowayout,
109 "Watchdog cannot be stopped once started (default="
110 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
112 static int kempld_wdt_set_stage_action(struct kempld_wdt_data *wdt_data,
113 struct kempld_wdt_stage *stage,
116 struct kempld_device_data *pld = wdt_data->pld;
119 if (!stage || !stage->mask)
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);
127 if (action == ACTION_RESET)
128 stage_cfg |= STAGE_CFG_ASSERT;
130 stage_cfg &= ~STAGE_CFG_ASSERT;
132 kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), stage_cfg);
133 kempld_release_mutex(pld);
138 static int kempld_wdt_set_stage_timeout(struct kempld_wdt_data *wdt_data,
139 struct kempld_wdt_stage *stage,
140 unsigned int timeout)
142 struct kempld_device_data *pld = wdt_data->pld;
149 prescaler = kempld_prescaler[PRESCALER_21];
154 stage_timeout64 = (u64)timeout * pld->pld_clock;
155 remainder = do_div(stage_timeout64, prescaler);
159 if (stage_timeout64 > stage->mask)
162 stage_timeout = stage_timeout64 & stage->mask;
164 kempld_get_mutex(pld);
165 stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
166 stage_cfg &= ~STAGE_CFG_PRESCALER_MASK;
167 stage_cfg |= STAGE_CFG_SET_PRESCALER(PRESCALER_21);
168 kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), stage_cfg);
169 kempld_write32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id),
171 kempld_release_mutex(pld);
177 * kempld_get_mutex must be called prior to calling this function.
179 static unsigned int kempld_wdt_get_timeout(struct kempld_wdt_data *wdt_data,
180 struct kempld_wdt_stage *stage)
182 struct kempld_device_data *pld = wdt_data->pld;
183 unsigned int timeout;
192 stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
193 stage_timeout = kempld_read32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id));
194 prescaler = kempld_prescaler[STAGE_CFG_GET_PRESCALER(stage_cfg)];
196 stage_timeout = (stage_timeout & stage->mask) * prescaler;
197 remainder = do_div(stage_timeout, pld->pld_clock);
201 timeout = stage_timeout;
202 WARN_ON_ONCE(timeout != stage_timeout);
207 static int kempld_wdt_set_timeout(struct watchdog_device *wdd,
208 unsigned int timeout)
210 struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
211 struct kempld_wdt_stage *pretimeout_stage;
212 struct kempld_wdt_stage *timeout_stage;
215 timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
216 pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
218 if (pretimeout_stage->mask && wdt_data->pretimeout > 0)
219 timeout = wdt_data->pretimeout;
221 ret = kempld_wdt_set_stage_action(wdt_data, timeout_stage,
225 ret = kempld_wdt_set_stage_timeout(wdt_data, timeout_stage,
230 wdd->timeout = timeout;
234 static int kempld_wdt_set_pretimeout(struct watchdog_device *wdd,
235 unsigned int pretimeout)
237 struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
238 struct kempld_wdt_stage *pretimeout_stage;
239 u8 action = ACTION_NONE;
242 pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
244 if (!pretimeout_stage->mask)
247 if (pretimeout > wdd->timeout)
253 ret = kempld_wdt_set_stage_action(wdt_data, pretimeout_stage,
257 ret = kempld_wdt_set_stage_timeout(wdt_data, pretimeout_stage,
258 wdd->timeout - pretimeout);
262 wdt_data->pretimeout = pretimeout;
266 static void kempld_wdt_update_timeouts(struct kempld_wdt_data *wdt_data)
268 struct kempld_device_data *pld = wdt_data->pld;
269 struct kempld_wdt_stage *pretimeout_stage;
270 struct kempld_wdt_stage *timeout_stage;
271 unsigned int pretimeout, timeout;
273 pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
274 timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
276 kempld_get_mutex(pld);
277 pretimeout = kempld_wdt_get_timeout(wdt_data, pretimeout_stage);
278 timeout = kempld_wdt_get_timeout(wdt_data, timeout_stage);
279 kempld_release_mutex(pld);
282 wdt_data->pretimeout = timeout;
284 wdt_data->pretimeout = 0;
286 wdt_data->wdd.timeout = pretimeout + timeout;
289 static int kempld_wdt_start(struct watchdog_device *wdd)
291 struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
292 struct kempld_device_data *pld = wdt_data->pld;
296 ret = kempld_wdt_set_timeout(wdd, wdd->timeout);
300 kempld_get_mutex(pld);
301 status = kempld_read8(pld, KEMPLD_WDT_CFG);
302 status |= KEMPLD_WDT_CFG_ENABLE;
303 kempld_write8(pld, KEMPLD_WDT_CFG, status);
304 status = kempld_read8(pld, KEMPLD_WDT_CFG);
305 kempld_release_mutex(pld);
307 /* Check if the watchdog was enabled */
308 if (!(status & KEMPLD_WDT_CFG_ENABLE))
314 static int kempld_wdt_stop(struct watchdog_device *wdd)
316 struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
317 struct kempld_device_data *pld = wdt_data->pld;
320 kempld_get_mutex(pld);
321 status = kempld_read8(pld, KEMPLD_WDT_CFG);
322 status &= ~KEMPLD_WDT_CFG_ENABLE;
323 kempld_write8(pld, KEMPLD_WDT_CFG, status);
324 status = kempld_read8(pld, KEMPLD_WDT_CFG);
325 kempld_release_mutex(pld);
327 /* Check if the watchdog was disabled */
328 if (status & KEMPLD_WDT_CFG_ENABLE)
334 static int kempld_wdt_keepalive(struct watchdog_device *wdd)
336 struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
337 struct kempld_device_data *pld = wdt_data->pld;
339 kempld_get_mutex(pld);
340 kempld_write8(pld, KEMPLD_WDT_KICK, 'K');
341 kempld_release_mutex(pld);
346 static long kempld_wdt_ioctl(struct watchdog_device *wdd, unsigned int cmd,
349 struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
350 void __user *argp = (void __user *)arg;
351 int ret = -ENOIOCTLCMD;
352 int __user *p = argp;
356 case WDIOC_SETPRETIMEOUT:
357 if (get_user(new_value, p))
359 ret = kempld_wdt_set_pretimeout(wdd, new_value);
362 ret = kempld_wdt_keepalive(wdd);
364 case WDIOC_GETPRETIMEOUT:
365 ret = put_user(wdt_data->pretimeout, (int __user *)arg);
372 static int kempld_wdt_probe_stages(struct watchdog_device *wdd)
374 struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
375 struct kempld_device_data *pld = wdt_data->pld;
376 struct kempld_wdt_stage *pretimeout_stage;
377 struct kempld_wdt_stage *timeout_stage;
378 u8 index, data, data_orig;
382 pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
383 timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
385 pretimeout_stage->mask = 0;
386 timeout_stage->mask = 0;
388 for (i = 0; i < 3; i++) {
389 index = KEMPLD_WDT_STAGE_TIMEOUT(i);
392 kempld_get_mutex(pld);
393 /* Probe each byte individually. */
394 for (j = 0; j < 4; j++) {
395 data_orig = kempld_read8(pld, index + j);
396 kempld_write8(pld, index + j, 0x00);
397 data = kempld_read8(pld, index + j);
398 /* A failed write means this byte is reserved */
401 kempld_write8(pld, index + j, data_orig);
402 mask |= 0xff << (j * 8);
404 kempld_release_mutex(pld);
406 /* Assign available stages to timeout and pretimeout */
407 if (!timeout_stage->mask) {
408 timeout_stage->mask = mask;
409 timeout_stage->id = i;
411 if (pld->feature_mask & KEMPLD_FEATURE_BIT_NMI) {
412 pretimeout_stage->mask = timeout_stage->mask;
413 timeout_stage->mask = mask;
414 pretimeout_stage->id = timeout_stage->id;
415 timeout_stage->id = i;
421 if (!timeout_stage->mask)
427 static const struct watchdog_info kempld_wdt_info = {
428 .identity = "KEMPLD Watchdog",
429 .options = WDIOF_SETTIMEOUT |
430 WDIOF_KEEPALIVEPING |
435 static const struct watchdog_ops kempld_wdt_ops = {
436 .owner = THIS_MODULE,
437 .start = kempld_wdt_start,
438 .stop = kempld_wdt_stop,
439 .ping = kempld_wdt_keepalive,
440 .set_timeout = kempld_wdt_set_timeout,
441 .ioctl = kempld_wdt_ioctl,
444 static int kempld_wdt_probe(struct platform_device *pdev)
446 struct kempld_device_data *pld = dev_get_drvdata(pdev->dev.parent);
447 struct kempld_wdt_data *wdt_data;
448 struct device *dev = &pdev->dev;
449 struct watchdog_device *wdd;
453 wdt_data = devm_kzalloc(dev, sizeof(*wdt_data), GFP_KERNEL);
458 wdd = &wdt_data->wdd;
461 kempld_get_mutex(pld);
462 status = kempld_read8(pld, KEMPLD_WDT_CFG);
463 kempld_release_mutex(pld);
465 /* Enable nowayout if watchdog is already locked */
466 if (status & (KEMPLD_WDT_CFG_ENABLE_LOCK |
467 KEMPLD_WDT_CFG_GLOBAL_LOCK)) {
470 "Forcing nowayout - watchdog lock enabled!\n");
474 wdd->info = &kempld_wdt_info;
475 wdd->ops = &kempld_wdt_ops;
477 watchdog_set_drvdata(wdd, wdt_data);
478 watchdog_set_nowayout(wdd, nowayout);
480 ret = kempld_wdt_probe_stages(wdd);
484 kempld_wdt_set_timeout(wdd, timeout);
485 kempld_wdt_set_pretimeout(wdd, pretimeout);
487 /* Check if watchdog is already enabled */
488 if (status & KEMPLD_WDT_CFG_ENABLE) {
489 /* Get current watchdog settings */
490 kempld_wdt_update_timeouts(wdt_data);
491 dev_info(dev, "Watchdog was already enabled\n");
494 platform_set_drvdata(pdev, wdt_data);
495 ret = watchdog_register_device(wdd);
499 dev_info(dev, "Watchdog registered with %ds timeout\n", wdd->timeout);
504 static void kempld_wdt_shutdown(struct platform_device *pdev)
506 struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
508 kempld_wdt_stop(&wdt_data->wdd);
511 static int kempld_wdt_remove(struct platform_device *pdev)
513 struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
514 struct watchdog_device *wdd = &wdt_data->wdd;
518 ret = kempld_wdt_stop(wdd);
519 watchdog_unregister_device(wdd);
525 /* Disable watchdog if it is active during suspend */
526 static int kempld_wdt_suspend(struct platform_device *pdev,
527 pm_message_t message)
529 struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
530 struct kempld_device_data *pld = wdt_data->pld;
531 struct watchdog_device *wdd = &wdt_data->wdd;
533 kempld_get_mutex(pld);
534 wdt_data->pm_status_store = kempld_read8(pld, KEMPLD_WDT_CFG);
535 kempld_release_mutex(pld);
537 kempld_wdt_update_timeouts(wdt_data);
539 if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE)
540 return kempld_wdt_stop(wdd);
545 /* Enable watchdog and configure it if necessary */
546 static int kempld_wdt_resume(struct platform_device *pdev)
548 struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
549 struct watchdog_device *wdd = &wdt_data->wdd;
552 * If watchdog was stopped before suspend be sure it gets disabled
553 * again, for the case BIOS has enabled it during resume
555 if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE)
556 return kempld_wdt_start(wdd);
558 return kempld_wdt_stop(wdd);
561 #define kempld_wdt_suspend NULL
562 #define kempld_wdt_resume NULL
565 static struct platform_driver kempld_wdt_driver = {
567 .name = "kempld-wdt",
569 .probe = kempld_wdt_probe,
570 .remove = kempld_wdt_remove,
571 .shutdown = kempld_wdt_shutdown,
572 .suspend = kempld_wdt_suspend,
573 .resume = kempld_wdt_resume,
576 module_platform_driver(kempld_wdt_driver);
578 MODULE_DESCRIPTION("KEM PLD Watchdog Driver");
579 MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
580 MODULE_LICENSE("GPL");