summaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/wdat_wdt.c
blob: e6f95e99156dbb1aecddc57e7e9a47b997d07cfe (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
// SPDX-License-Identifier: GPL-2.0-only
/*
 * ACPI Hardware Watchdog (WDAT) driver.
 *
 * Copyright (C) 2016, Intel Corporation
 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
 */

#include <linux/acpi.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/watchdog.h>

#define MAX_WDAT_ACTIONS ACPI_WDAT_ACTION_RESERVED

/**
 * struct wdat_instruction - Single ACPI WDAT instruction
 * @entry: Copy of the ACPI table instruction
 * @reg: Register the instruction is accessing
 * @node: Next instruction in action sequence
 */
struct wdat_instruction {
	struct acpi_wdat_entry entry;
	void __iomem *reg;
	struct list_head node;
};

/**
 * struct wdat_wdt - ACPI WDAT watchdog device
 * @pdev: Parent platform device
 * @wdd: Watchdog core device
 * @period: How long is one watchdog period in ms
 * @stopped_in_sleep: Is this watchdog stopped by the firmware in S1-S5
 * @stopped: Was the watchdog stopped by the driver in suspend
 * @instructions: An array of instruction lists indexed by an action number from
 *                the WDAT table. There can be %NULL entries for not implemented
 *                actions.
 */
struct wdat_wdt {
	struct platform_device *pdev;
	struct watchdog_device wdd;
	unsigned int period;
	bool stopped_in_sleep;
	bool stopped;
	struct list_head *instructions[MAX_WDAT_ACTIONS];
};

#define to_wdat_wdt(wdd) container_of(wdd, struct wdat_wdt, wdd)

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

#define WDAT_DEFAULT_TIMEOUT	30

static int timeout = WDAT_DEFAULT_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
		 __MODULE_STRING(WDAT_DEFAULT_TIMEOUT) ")");

static int wdat_wdt_read(struct wdat_wdt *wdat,
	 const struct wdat_instruction *instr, u32 *value)
{
	const struct acpi_generic_address *gas = &instr->entry.register_region;

	switch (gas->access_width) {
	case 1:
		*value = ioread8(instr->reg);
		break;
	case 2:
		*value = ioread16(instr->reg);
		break;
	case 3:
		*value = ioread32(instr->reg);
		break;
	default:
		return -EINVAL;
	}

	dev_dbg(&wdat->pdev->dev, "Read %#x from 0x%08llx\n", *value,
		gas->address);

	return 0;
}

static int wdat_wdt_write(struct wdat_wdt *wdat,
	const struct wdat_instruction *instr, u32 value)
{
	const struct acpi_generic_address *gas = &instr->entry.register_region;

	switch (gas->access_width) {
	case 1:
		iowrite8((u8)value, instr->reg);
		break;
	case 2:
		iowrite16((u16)value, instr->reg);
		break;
	case 3:
		iowrite32(value, instr->reg);
		break;
	default:
		return -EINVAL;
	}

	dev_dbg(&wdat->pdev->dev, "Wrote %#x to 0x%08llx\n", value,
		gas->address);

	return 0;
}

static int wdat_wdt_run_action(struct wdat_wdt *wdat, unsigned int action,
			       u32 param, u32 *retval)
{
	struct wdat_instruction *instr;

	if (action >= ARRAY_SIZE(wdat->instructions))
		return -EINVAL;

	if (!wdat->instructions[action])
		return -EOPNOTSUPP;

	dev_dbg(&wdat->pdev->dev, "Running action %#x\n", action);

	/* Run each instruction sequentially */
	list_for_each_entry(instr, wdat->instructions[action], node) {
		const struct acpi_wdat_entry *entry = &instr->entry;
		const struct acpi_generic_address *gas;
		u32 flags, value, mask, x, y;
		bool preserve;
		int ret;

		gas = &entry->register_region;

		preserve = entry->instruction & ACPI_WDAT_PRESERVE_REGISTER;
		flags = entry->instruction & ~ACPI_WDAT_PRESERVE_REGISTER;
		value = entry->value;
		mask = entry->mask;

		switch (flags) {
		case ACPI_WDAT_READ_VALUE:
			ret = wdat_wdt_read(wdat, instr, &x);
			if (ret)
				return ret;
			x >>= gas->bit_offset;
			x &= mask;
			if (retval)
				*retval = x == value;
			break;

		case ACPI_WDAT_READ_COUNTDOWN:
			ret = wdat_wdt_read(wdat, instr, &x);
			if (ret)
				return ret;
			x >>= gas->bit_offset;
			x &= mask;
			if (retval)
				*retval = x;
			break;

		case ACPI_WDAT_WRITE_VALUE:
			x = value & mask;
			x <<= gas->bit_offset;
			if (preserve) {
				ret = wdat_wdt_read(wdat, instr, &y);
				if (ret)
					return ret;
				y = y & ~(mask << gas->bit_offset);
				x |= y;
			}
			ret = wdat_wdt_write(wdat, instr, x);
			if (ret)
				return ret;
			break;

		case ACPI_WDAT_WRITE_COUNTDOWN:
			x = param;
			x &= mask;
			x <<= gas->bit_offset;
			if (preserve) {
				ret = wdat_wdt_read(wdat, instr, &y);
				if (ret)
					return ret;
				y = y & ~(mask << gas->bit_offset);
				x |= y;
			}
			ret = wdat_wdt_write(wdat, instr, x);
			if (ret)
				return ret;
			break;

		default:
			dev_err(&wdat->pdev->dev, "Unknown instruction: %u\n",
				flags);
			return -EINVAL;
		}
	}

	return 0;
}

static int wdat_wdt_enable_reboot(struct wdat_wdt *wdat)
{
	int ret;

	/*
	 * WDAT specification says that the watchdog is required to reboot
	 * the system when it fires. However, it also states that it is
	 * recommended to make it configurable through hardware register. We
	 * enable reboot now if it is configurable, just in case.
	 */
	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_REBOOT, 0, NULL);
	if (ret && ret != -EOPNOTSUPP) {
		dev_err(&wdat->pdev->dev,
			"Failed to enable reboot when watchdog triggers\n");
		return ret;
	}

	return 0;
}

static void wdat_wdt_boot_status(struct wdat_wdt *wdat)
{
	u32 boot_status = 0;
	int ret;

	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_GET_STATUS, 0, &boot_status);
	if (ret && ret != -EOPNOTSUPP) {
		dev_err(&wdat->pdev->dev, "Failed to read boot status\n");
		return;
	}

	if (boot_status)
		wdat->wdd.bootstatus = WDIOF_CARDRESET;

	/* Clear the boot status in case BIOS did not do it */
	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_STATUS, 0, NULL);
	if (ret && ret != -EOPNOTSUPP)
		dev_err(&wdat->pdev->dev, "Failed to clear boot status\n");
}

static void wdat_wdt_set_running(struct wdat_wdt *wdat)
{
	u32 running = 0;
	int ret;

	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_GET_RUNNING_STATE, 0,
				  &running);
	if (ret && ret != -EOPNOTSUPP)
		dev_err(&wdat->pdev->dev, "Failed to read running state\n");

	if (running)
		set_bit(WDOG_HW_RUNNING, &wdat->wdd.status);
}

static int wdat_wdt_start(struct watchdog_device *wdd)
{
	return wdat_wdt_run_action(to_wdat_wdt(wdd),
				   ACPI_WDAT_SET_RUNNING_STATE, 0, NULL);
}

static int wdat_wdt_stop(struct watchdog_device *wdd)
{
	return wdat_wdt_run_action(to_wdat_wdt(wdd),
				   ACPI_WDAT_SET_STOPPED_STATE, 0, NULL);
}

static int wdat_wdt_ping(struct watchdog_device *wdd)
{
	return wdat_wdt_run_action(to_wdat_wdt(wdd), ACPI_WDAT_RESET, 0, NULL);
}

static int wdat_wdt_set_timeout(struct watchdog_device *wdd,
				unsigned int timeout)
{
	struct wdat_wdt *wdat = to_wdat_wdt(wdd);
	unsigned int periods;
	int ret;

	periods = timeout * 1000 / wdat->period;
	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_COUNTDOWN, periods, NULL);
	if (!ret)
		wdd->timeout = timeout;
	return ret;
}

static unsigned int wdat_wdt_get_timeleft(struct watchdog_device *wdd)
{
	struct wdat_wdt *wdat = to_wdat_wdt(wdd);
	u32 periods = 0;

	wdat_wdt_run_action(wdat, ACPI_WDAT_GET_CURRENT_COUNTDOWN, 0, &periods);
	return periods * wdat->period / 1000;
}

static const struct watchdog_info wdat_wdt_info = {
	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
	.firmware_version = 0,
	.identity = "wdat_wdt",
};

static const struct watchdog_ops wdat_wdt_ops = {
	.owner = THIS_MODULE,
	.start = wdat_wdt_start,
	.stop = wdat_wdt_stop,
	.ping = wdat_wdt_ping,
	.set_timeout = wdat_wdt_set_timeout,
	.get_timeleft = wdat_wdt_get_timeleft,
};

static int wdat_wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	const struct acpi_wdat_entry *entries;
	const struct acpi_table_wdat *tbl;
	struct wdat_wdt *wdat;
	struct resource *res;
	void __iomem **regs;
	acpi_status status;
	int i, ret;

	status = acpi_get_table(ACPI_SIG_WDAT, 0,
				(struct acpi_table_header **)&tbl);
	if (ACPI_FAILURE(status))
		return -ENODEV;

	wdat = devm_kzalloc(dev, sizeof(*wdat), GFP_KERNEL);
	if (!wdat)
		return -ENOMEM;

	regs = devm_kcalloc(dev, pdev->num_resources, sizeof(*regs),
			    GFP_KERNEL);
	if (!regs)
		return -ENOMEM;

	/* WDAT specification wants to have >= 1ms period */
	if (tbl->timer_period < 1)
		return -EINVAL;
	if (tbl->min_count > tbl->max_count)
		return -EINVAL;

	wdat->period = tbl->timer_period;
	wdat->wdd.min_hw_heartbeat_ms = wdat->period * tbl->min_count;
	wdat->wdd.max_hw_heartbeat_ms = wdat->period * tbl->max_count;
	wdat->wdd.min_timeout = 1;
	wdat->stopped_in_sleep = tbl->flags & ACPI_WDAT_STOPPED;
	wdat->wdd.info = &wdat_wdt_info;
	wdat->wdd.ops = &wdat_wdt_ops;
	wdat->pdev = pdev;

	/* Request and map all resources */
	for (i = 0; i < pdev->num_resources; i++) {
		void __iomem *reg;

		res = &pdev->resource[i];
		if (resource_type(res) == IORESOURCE_MEM) {
			reg = devm_ioremap_resource(dev, res);
			if (IS_ERR(reg))
				return PTR_ERR(reg);
		} else if (resource_type(res) == IORESOURCE_IO) {
			reg = devm_ioport_map(dev, res->start, 1);
			if (!reg)
				return -ENOMEM;
		} else {
			dev_err(dev, "Unsupported resource\n");
			return -EINVAL;
		}

		regs[i] = reg;
	}

	entries = (struct acpi_wdat_entry *)(tbl + 1);
	for (i = 0; i < tbl->entries; i++) {
		const struct acpi_generic_address *gas;
		struct wdat_instruction *instr;
		struct list_head *instructions;
		unsigned int action;
		struct resource r;
		int j;

		action = entries[i].action;
		if (action >= MAX_WDAT_ACTIONS) {
			dev_dbg(dev, "Skipping unknown action: %u\n", action);
			continue;
		}

		instr = devm_kzalloc(dev, sizeof(*instr), GFP_KERNEL);
		if (!instr)
			return -ENOMEM;

		INIT_LIST_HEAD(&instr->node);
		instr->entry = entries[i];

		gas = &entries[i].register_region;

		memset(&r, 0, sizeof(r));
		r.start = gas->address;
		r.end = r.start + ACPI_ACCESS_BYTE_WIDTH(gas->access_width) - 1;
		if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
			r.flags = IORESOURCE_MEM;
		} else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
			r.flags = IORESOURCE_IO;
		} else {
			dev_dbg(dev, "Unsupported address space: %d\n",
				gas->space_id);
			continue;
		}

		/* Find the matching resource */
		for (j = 0; j < pdev->num_resources; j++) {
			res = &pdev->resource[j];
			if (resource_contains(res, &r)) {
				instr->reg = regs[j] + r.start - res->start;
				break;
			}
		}

		if (!instr->reg) {
			dev_err(dev, "I/O resource not found\n");
			return -EINVAL;
		}

		instructions = wdat->instructions[action];
		if (!instructions) {
			instructions = devm_kzalloc(dev,
						    sizeof(*instructions),
						    GFP_KERNEL);
			if (!instructions)
				return -ENOMEM;

			INIT_LIST_HEAD(instructions);
			wdat->instructions[action] = instructions;
		}

		list_add_tail(&instr->node, instructions);
	}

	wdat_wdt_boot_status(wdat);
	wdat_wdt_set_running(wdat);

	ret = wdat_wdt_enable_reboot(wdat);
	if (ret)
		return ret;

	platform_set_drvdata(pdev, wdat);

	/*
	 * Set initial timeout so that userspace has time to configure the
	 * watchdog properly after it has opened the device. In some cases
	 * the BIOS default is too short and causes immediate reboot.
	 */
	if (watchdog_timeout_invalid(&wdat->wdd, timeout)) {
		dev_warn(dev, "Invalid timeout %d given, using %d\n",
			 timeout, WDAT_DEFAULT_TIMEOUT);
		timeout = WDAT_DEFAULT_TIMEOUT;
	}

	ret = wdat_wdt_set_timeout(&wdat->wdd, timeout);
	if (ret)
		return ret;

	watchdog_set_nowayout(&wdat->wdd, nowayout);
	watchdog_stop_on_reboot(&wdat->wdd);
	watchdog_stop_on_unregister(&wdat->wdd);
	return devm_watchdog_register_device(dev, &wdat->wdd);
}

#ifdef CONFIG_PM_SLEEP
static int wdat_wdt_suspend_noirq(struct device *dev)
{
	struct wdat_wdt *wdat = dev_get_drvdata(dev);
	int ret;

	if (!watchdog_active(&wdat->wdd))
		return 0;

	/*
	 * We need to stop the watchdog if firmware is not doing it or if we
	 * are going suspend to idle (where firmware is not involved). If
	 * firmware is stopping the watchdog we kick it here one more time
	 * to give it some time.
	 */
	wdat->stopped = false;
	if (acpi_target_system_state() == ACPI_STATE_S0 ||
	    !wdat->stopped_in_sleep) {
		ret = wdat_wdt_stop(&wdat->wdd);
		if (!ret)
			wdat->stopped = true;
	} else {
		ret = wdat_wdt_ping(&wdat->wdd);
	}

	return ret;
}

static int wdat_wdt_resume_noirq(struct device *dev)
{
	struct wdat_wdt *wdat = dev_get_drvdata(dev);
	int ret;

	if (!watchdog_active(&wdat->wdd))
		return 0;

	if (!wdat->stopped) {
		/*
		 * Looks like the boot firmware reinitializes the watchdog
		 * before it hands off to the OS on resume from sleep so we
		 * stop and reprogram the watchdog here.
		 */
		ret = wdat_wdt_stop(&wdat->wdd);
		if (ret)
			return ret;

		ret = wdat_wdt_set_timeout(&wdat->wdd, wdat->wdd.timeout);
		if (ret)
			return ret;

		ret = wdat_wdt_enable_reboot(wdat);
		if (ret)
			return ret;

		ret = wdat_wdt_ping(&wdat->wdd);
		if (ret)
			return ret;
	}

	return wdat_wdt_start(&wdat->wdd);
}
#endif

static const struct dev_pm_ops wdat_wdt_pm_ops = {
	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(wdat_wdt_suspend_noirq,
				      wdat_wdt_resume_noirq)
};

static struct platform_driver wdat_wdt_driver = {
	.probe = wdat_wdt_probe,
	.driver = {
		.name = "wdat_wdt",
		.pm = &wdat_wdt_pm_ops,
	},
};

module_platform_driver(wdat_wdt_driver);

MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
MODULE_DESCRIPTION("ACPI Hardware Watchdog (WDAT) driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:wdat_wdt");