1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Starfive Watchdog driver
4  *
5  * Copyright (C) 2022 StarFive Technology Co., Ltd.
6  */
7 
8 #include <linux/clk.h>
9 #include <linux/iopoll.h>
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/platform_device.h>
13 #include <linux/pm_runtime.h>
14 #include <linux/reset.h>
15 #include <linux/watchdog.h>
16 
17 /* JH7100 Watchdog register define */
18 #define STARFIVE_WDT_JH7100_INTSTAUS	0x000
19 #define STARFIVE_WDT_JH7100_CONTROL	0x104
20 #define STARFIVE_WDT_JH7100_LOAD	0x108
21 #define STARFIVE_WDT_JH7100_EN		0x110
22 #define STARFIVE_WDT_JH7100_RELOAD	0x114	/* Write 0 or 1 to reload preset value */
23 #define STARFIVE_WDT_JH7100_VALUE	0x118
24 #define STARFIVE_WDT_JH7100_INTCLR	0x120	/*
25 						 * [0]: Write 1 to clear interrupt
26 						 * [1]: 1 mean clearing and 0 mean complete
27 						 * [31:2]: reserved.
28 						 */
29 #define STARFIVE_WDT_JH7100_LOCK	0x13c	/* write 0x378f0765 to unlock */
30 
31 /* JH7110 Watchdog register define */
32 #define STARFIVE_WDT_JH7110_LOAD	0x000
33 #define STARFIVE_WDT_JH7110_VALUE	0x004
34 #define STARFIVE_WDT_JH7110_CONTROL	0x008	/*
35 						 * [0]: reset enable;
36 						 * [1]: interrupt enable && watchdog enable
37 						 * [31:2]: reserved.
38 						 */
39 #define STARFIVE_WDT_JH7110_INTCLR	0x00c	/* clear intterupt and reload the counter */
40 #define STARFIVE_WDT_JH7110_IMS		0x014
41 #define STARFIVE_WDT_JH7110_LOCK	0xc00	/* write 0x1ACCE551 to unlock */
42 
43 /* WDOGCONTROL */
44 #define STARFIVE_WDT_ENABLE			0x1
45 #define STARFIVE_WDT_EN_SHIFT			0
46 #define STARFIVE_WDT_RESET_EN			0x1
47 #define STARFIVE_WDT_JH7100_RST_EN_SHIFT	0
48 #define STARFIVE_WDT_JH7110_RST_EN_SHIFT	1
49 
50 /* WDOGLOCK */
51 #define STARFIVE_WDT_JH7100_UNLOCK_KEY		0x378f0765
52 #define STARFIVE_WDT_JH7110_UNLOCK_KEY		0x1acce551
53 
54 /* WDOGINTCLR */
55 #define STARFIVE_WDT_INTCLR			0x1
56 #define STARFIVE_WDT_JH7100_INTCLR_AVA_SHIFT	1	/* Watchdog can clear interrupt when 0 */
57 
58 #define STARFIVE_WDT_MAXCNT			0xffffffff
59 #define STARFIVE_WDT_DEFAULT_TIME		(15)
60 #define STARFIVE_WDT_DELAY_US			0
61 #define STARFIVE_WDT_TIMEOUT_US			10000
62 
63 /* module parameter */
64 #define STARFIVE_WDT_EARLY_ENA			0
65 
66 static bool nowayout = WATCHDOG_NOWAYOUT;
67 static int heartbeat;
68 static bool early_enable = STARFIVE_WDT_EARLY_ENA;
69 
70 module_param(heartbeat, int, 0);
71 module_param(early_enable, bool, 0);
72 module_param(nowayout, bool, 0);
73 
74 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (default="
75 		 __MODULE_STRING(STARFIVE_WDT_DEFAULT_TIME) ")");
76 MODULE_PARM_DESC(early_enable,
77 		 "Watchdog is started at boot time if set to 1, default="
78 		 __MODULE_STRING(STARFIVE_WDT_EARLY_ENA));
79 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
80 		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
81 
82 struct starfive_wdt_variant {
83 	unsigned int control;		/* Watchdog Control Resgister for reset enable */
84 	unsigned int load;		/* Watchdog Load register */
85 	unsigned int reload;		/* Watchdog Reload Control register */
86 	unsigned int enable;		/* Watchdog Enable Register */
87 	unsigned int value;		/* Watchdog Counter Value Register */
88 	unsigned int int_clr;		/* Watchdog Interrupt Clear Register */
89 	unsigned int unlock;		/* Watchdog Lock Register */
90 	unsigned int int_status;	/* Watchdog Interrupt Status Register */
91 
92 	u32 unlock_key;
93 	char enrst_shift;
94 	char en_shift;
95 	bool intclr_check;		/*  whether need to check it before clearing interrupt */
96 	char intclr_ava_shift;
97 	bool double_timeout;		/* The watchdog need twice timeout to reboot */
98 };
99 
100 struct starfive_wdt {
101 	struct watchdog_device wdd;
102 	spinlock_t lock;		/* spinlock for register handling */
103 	void __iomem *base;
104 	struct clk *core_clk;
105 	struct clk *apb_clk;
106 	const struct starfive_wdt_variant *variant;
107 	unsigned long freq;
108 	u32 count;			/* count of timeout */
109 	u32 reload;			/* restore the count */
110 };
111 
112 /* Register layout and configuration for the JH7100 */
113 static const struct starfive_wdt_variant starfive_wdt_jh7100_variant = {
114 	.control = STARFIVE_WDT_JH7100_CONTROL,
115 	.load = STARFIVE_WDT_JH7100_LOAD,
116 	.reload = STARFIVE_WDT_JH7100_RELOAD,
117 	.enable = STARFIVE_WDT_JH7100_EN,
118 	.value = STARFIVE_WDT_JH7100_VALUE,
119 	.int_clr = STARFIVE_WDT_JH7100_INTCLR,
120 	.unlock = STARFIVE_WDT_JH7100_LOCK,
121 	.unlock_key = STARFIVE_WDT_JH7100_UNLOCK_KEY,
122 	.int_status = STARFIVE_WDT_JH7100_INTSTAUS,
123 	.enrst_shift = STARFIVE_WDT_JH7100_RST_EN_SHIFT,
124 	.en_shift = STARFIVE_WDT_EN_SHIFT,
125 	.intclr_check = true,
126 	.intclr_ava_shift = STARFIVE_WDT_JH7100_INTCLR_AVA_SHIFT,
127 	.double_timeout = false,
128 };
129 
130 /* Register layout and configuration for the JH7110 */
131 static const struct starfive_wdt_variant starfive_wdt_jh7110_variant = {
132 	.control = STARFIVE_WDT_JH7110_CONTROL,
133 	.load = STARFIVE_WDT_JH7110_LOAD,
134 	.enable = STARFIVE_WDT_JH7110_CONTROL,
135 	.value = STARFIVE_WDT_JH7110_VALUE,
136 	.int_clr = STARFIVE_WDT_JH7110_INTCLR,
137 	.unlock = STARFIVE_WDT_JH7110_LOCK,
138 	.unlock_key = STARFIVE_WDT_JH7110_UNLOCK_KEY,
139 	.int_status = STARFIVE_WDT_JH7110_IMS,
140 	.enrst_shift = STARFIVE_WDT_JH7110_RST_EN_SHIFT,
141 	.en_shift = STARFIVE_WDT_EN_SHIFT,
142 	.intclr_check = false,
143 	.double_timeout = true,
144 };
145 
starfive_wdt_enable_clock(struct starfive_wdt * wdt)146 static int starfive_wdt_enable_clock(struct starfive_wdt *wdt)
147 {
148 	int ret;
149 
150 	ret = clk_prepare_enable(wdt->apb_clk);
151 	if (ret)
152 		return dev_err_probe(wdt->wdd.parent, ret, "failed to enable apb clock\n");
153 
154 	ret = clk_prepare_enable(wdt->core_clk);
155 	if (ret) {
156 		clk_disable_unprepare(wdt->apb_clk);
157 		return dev_err_probe(wdt->wdd.parent, ret, "failed to enable core clock\n");
158 	}
159 
160 	return 0;
161 }
162 
starfive_wdt_disable_clock(struct starfive_wdt * wdt)163 static void starfive_wdt_disable_clock(struct starfive_wdt *wdt)
164 {
165 	clk_disable_unprepare(wdt->core_clk);
166 	clk_disable_unprepare(wdt->apb_clk);
167 }
168 
starfive_wdt_get_clock(struct starfive_wdt * wdt)169 static inline int starfive_wdt_get_clock(struct starfive_wdt *wdt)
170 {
171 	struct device *dev = wdt->wdd.parent;
172 
173 	wdt->apb_clk = devm_clk_get(dev, "apb");
174 	if (IS_ERR(wdt->apb_clk))
175 		return dev_err_probe(dev, PTR_ERR(wdt->apb_clk), "failed to get apb clock\n");
176 
177 	wdt->core_clk = devm_clk_get(dev, "core");
178 	if (IS_ERR(wdt->core_clk))
179 		return dev_err_probe(dev, PTR_ERR(wdt->core_clk), "failed to get core clock\n");
180 
181 	return 0;
182 }
183 
starfive_wdt_reset_init(struct device * dev)184 static inline int starfive_wdt_reset_init(struct device *dev)
185 {
186 	struct reset_control *rsts;
187 	int ret;
188 
189 	rsts = devm_reset_control_array_get_exclusive(dev);
190 	if (IS_ERR(rsts))
191 		return dev_err_probe(dev, PTR_ERR(rsts), "failed to get resets\n");
192 
193 	ret = reset_control_deassert(rsts);
194 	if (ret)
195 		return dev_err_probe(dev, ret, "failed to deassert resets\n");
196 
197 	return 0;
198 }
199 
starfive_wdt_ticks_to_sec(struct starfive_wdt * wdt,u32 ticks)200 static u32 starfive_wdt_ticks_to_sec(struct starfive_wdt *wdt, u32 ticks)
201 {
202 	return DIV_ROUND_CLOSEST(ticks, wdt->freq);
203 }
204 
205 /* Write unlock-key to unlock. Write other value to lock. */
starfive_wdt_unlock(struct starfive_wdt * wdt)206 static void starfive_wdt_unlock(struct starfive_wdt *wdt)
207 	__acquires(&wdt->lock)
208 {
209 	spin_lock(&wdt->lock);
210 	writel(wdt->variant->unlock_key, wdt->base + wdt->variant->unlock);
211 }
212 
starfive_wdt_lock(struct starfive_wdt * wdt)213 static void starfive_wdt_lock(struct starfive_wdt *wdt)
214 	__releases(&wdt->lock)
215 {
216 	writel(~wdt->variant->unlock_key, wdt->base + wdt->variant->unlock);
217 	spin_unlock(&wdt->lock);
218 }
219 
220 /* enable watchdog interrupt to reset/reboot */
starfive_wdt_enable_reset(struct starfive_wdt * wdt)221 static void starfive_wdt_enable_reset(struct starfive_wdt *wdt)
222 {
223 	u32 val;
224 
225 	val = readl(wdt->base + wdt->variant->control);
226 	val |= STARFIVE_WDT_RESET_EN << wdt->variant->enrst_shift;
227 	writel(val, wdt->base + wdt->variant->control);
228 }
229 
230 /* interrupt status whether has been raised from the counter */
starfive_wdt_raise_irq_status(struct starfive_wdt * wdt)231 static bool starfive_wdt_raise_irq_status(struct starfive_wdt *wdt)
232 {
233 	return !!readl(wdt->base + wdt->variant->int_status);
234 }
235 
236 /* waiting interrupt can be free to clear */
starfive_wdt_wait_int_free(struct starfive_wdt * wdt)237 static int starfive_wdt_wait_int_free(struct starfive_wdt *wdt)
238 {
239 	u32 value;
240 
241 	return readl_poll_timeout_atomic(wdt->base + wdt->variant->int_clr, value,
242 					 !(value & BIT(wdt->variant->intclr_ava_shift)),
243 					 STARFIVE_WDT_DELAY_US, STARFIVE_WDT_TIMEOUT_US);
244 }
245 
246 /* clear interrupt signal before initialization or reload */
starfive_wdt_int_clr(struct starfive_wdt * wdt)247 static int starfive_wdt_int_clr(struct starfive_wdt *wdt)
248 {
249 	int ret;
250 
251 	if (wdt->variant->intclr_check) {
252 		ret = starfive_wdt_wait_int_free(wdt);
253 		if (ret)
254 			return dev_err_probe(wdt->wdd.parent, ret,
255 					     "watchdog is not ready to clear interrupt.\n");
256 	}
257 	writel(STARFIVE_WDT_INTCLR, wdt->base + wdt->variant->int_clr);
258 
259 	return 0;
260 }
261 
starfive_wdt_set_count(struct starfive_wdt * wdt,u32 val)262 static inline void starfive_wdt_set_count(struct starfive_wdt *wdt, u32 val)
263 {
264 	writel(val, wdt->base + wdt->variant->load);
265 }
266 
starfive_wdt_get_count(struct starfive_wdt * wdt)267 static inline u32 starfive_wdt_get_count(struct starfive_wdt *wdt)
268 {
269 	return readl(wdt->base + wdt->variant->value);
270 }
271 
272 /* enable watchdog */
starfive_wdt_enable(struct starfive_wdt * wdt)273 static inline void starfive_wdt_enable(struct starfive_wdt *wdt)
274 {
275 	u32 val;
276 
277 	val = readl(wdt->base + wdt->variant->enable);
278 	val |= STARFIVE_WDT_ENABLE << wdt->variant->en_shift;
279 	writel(val, wdt->base + wdt->variant->enable);
280 }
281 
282 /* disable watchdog */
starfive_wdt_disable(struct starfive_wdt * wdt)283 static inline void starfive_wdt_disable(struct starfive_wdt *wdt)
284 {
285 	u32 val;
286 
287 	val = readl(wdt->base + wdt->variant->enable);
288 	val &= ~(STARFIVE_WDT_ENABLE << wdt->variant->en_shift);
289 	writel(val, wdt->base + wdt->variant->enable);
290 }
291 
starfive_wdt_set_reload_count(struct starfive_wdt * wdt,u32 count)292 static inline void starfive_wdt_set_reload_count(struct starfive_wdt *wdt, u32 count)
293 {
294 	starfive_wdt_set_count(wdt, count);
295 
296 	/* 7100 need set any value to reload register and could reload value to counter */
297 	if (wdt->variant->reload)
298 		writel(0x1, wdt->base + wdt->variant->reload);
299 }
300 
starfive_wdt_max_timeout(struct starfive_wdt * wdt)301 static unsigned int starfive_wdt_max_timeout(struct starfive_wdt *wdt)
302 {
303 	if (wdt->variant->double_timeout)
304 		return DIV_ROUND_UP(STARFIVE_WDT_MAXCNT, (wdt->freq / 2)) - 1;
305 
306 	return DIV_ROUND_UP(STARFIVE_WDT_MAXCNT, wdt->freq) - 1;
307 }
308 
starfive_wdt_get_timeleft(struct watchdog_device * wdd)309 static unsigned int starfive_wdt_get_timeleft(struct watchdog_device *wdd)
310 {
311 	struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
312 	u32 count;
313 
314 	/*
315 	 * If the watchdog takes twice timeout and set half count value,
316 	 * timeleft value should add the count value before first timeout.
317 	 */
318 	count = starfive_wdt_get_count(wdt);
319 	if (wdt->variant->double_timeout && !starfive_wdt_raise_irq_status(wdt))
320 		count += wdt->count;
321 
322 	return starfive_wdt_ticks_to_sec(wdt, count);
323 }
324 
starfive_wdt_keepalive(struct watchdog_device * wdd)325 static int starfive_wdt_keepalive(struct watchdog_device *wdd)
326 {
327 	struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
328 	int ret;
329 
330 	starfive_wdt_unlock(wdt);
331 	ret = starfive_wdt_int_clr(wdt);
332 	if (ret)
333 		goto exit;
334 
335 	starfive_wdt_set_reload_count(wdt, wdt->count);
336 
337 exit:
338 	/* exit with releasing spinlock and locking registers */
339 	starfive_wdt_lock(wdt);
340 	return ret;
341 }
342 
starfive_wdt_start(struct starfive_wdt * wdt)343 static int starfive_wdt_start(struct starfive_wdt *wdt)
344 {
345 	int ret;
346 
347 	starfive_wdt_unlock(wdt);
348 	/* disable watchdog, to be safe */
349 	starfive_wdt_disable(wdt);
350 
351 	starfive_wdt_enable_reset(wdt);
352 	ret = starfive_wdt_int_clr(wdt);
353 	if (ret)
354 		goto exit;
355 
356 	starfive_wdt_set_count(wdt, wdt->count);
357 	starfive_wdt_enable(wdt);
358 
359 exit:
360 	starfive_wdt_lock(wdt);
361 	return ret;
362 }
363 
starfive_wdt_stop(struct starfive_wdt * wdt)364 static void starfive_wdt_stop(struct starfive_wdt *wdt)
365 {
366 	starfive_wdt_unlock(wdt);
367 	starfive_wdt_disable(wdt);
368 	starfive_wdt_lock(wdt);
369 }
370 
starfive_wdt_pm_start(struct watchdog_device * wdd)371 static int starfive_wdt_pm_start(struct watchdog_device *wdd)
372 {
373 	struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
374 	int ret = pm_runtime_get_sync(wdd->parent);
375 
376 	if (ret < 0)
377 		return ret;
378 
379 	return starfive_wdt_start(wdt);
380 }
381 
starfive_wdt_pm_stop(struct watchdog_device * wdd)382 static int starfive_wdt_pm_stop(struct watchdog_device *wdd)
383 {
384 	struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
385 
386 	starfive_wdt_stop(wdt);
387 	return pm_runtime_put_sync(wdd->parent);
388 }
389 
starfive_wdt_set_timeout(struct watchdog_device * wdd,unsigned int timeout)390 static int starfive_wdt_set_timeout(struct watchdog_device *wdd,
391 				    unsigned int timeout)
392 {
393 	struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
394 	unsigned long count = timeout * wdt->freq;
395 
396 	/* some watchdogs take two timeouts to reset */
397 	if (wdt->variant->double_timeout)
398 		count /= 2;
399 
400 	wdt->count = count;
401 	wdd->timeout = timeout;
402 
403 	starfive_wdt_unlock(wdt);
404 	starfive_wdt_disable(wdt);
405 	starfive_wdt_set_reload_count(wdt, wdt->count);
406 	starfive_wdt_enable(wdt);
407 	starfive_wdt_lock(wdt);
408 
409 	return 0;
410 }
411 
412 #define STARFIVE_WDT_OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
413 
414 static const struct watchdog_info starfive_wdt_info = {
415 	.options = STARFIVE_WDT_OPTIONS,
416 	.identity = "StarFive Watchdog",
417 };
418 
419 static const struct watchdog_ops starfive_wdt_ops = {
420 	.owner = THIS_MODULE,
421 	.start = starfive_wdt_pm_start,
422 	.stop = starfive_wdt_pm_stop,
423 	.ping = starfive_wdt_keepalive,
424 	.set_timeout = starfive_wdt_set_timeout,
425 	.get_timeleft = starfive_wdt_get_timeleft,
426 };
427 
starfive_wdt_probe(struct platform_device * pdev)428 static int starfive_wdt_probe(struct platform_device *pdev)
429 {
430 	struct starfive_wdt *wdt;
431 	int ret;
432 
433 	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
434 	if (!wdt)
435 		return -ENOMEM;
436 
437 	wdt->base = devm_platform_ioremap_resource(pdev, 0);
438 	if (IS_ERR(wdt->base))
439 		return dev_err_probe(&pdev->dev, PTR_ERR(wdt->base), "error mapping registers\n");
440 
441 	wdt->wdd.parent = &pdev->dev;
442 	ret = starfive_wdt_get_clock(wdt);
443 	if (ret)
444 		return ret;
445 
446 	platform_set_drvdata(pdev, wdt);
447 	pm_runtime_enable(&pdev->dev);
448 	if (pm_runtime_enabled(&pdev->dev)) {
449 		ret = pm_runtime_get_sync(&pdev->dev);
450 		if (ret < 0)
451 			return ret;
452 	} else {
453 		/* runtime PM is disabled but clocks need to be enabled */
454 		ret = starfive_wdt_enable_clock(wdt);
455 		if (ret)
456 			return ret;
457 	}
458 
459 	ret = starfive_wdt_reset_init(&pdev->dev);
460 	if (ret)
461 		goto err_exit;
462 
463 	watchdog_set_drvdata(&wdt->wdd, wdt);
464 	wdt->wdd.info = &starfive_wdt_info;
465 	wdt->wdd.ops = &starfive_wdt_ops;
466 	wdt->variant = of_device_get_match_data(&pdev->dev);
467 	spin_lock_init(&wdt->lock);
468 
469 	wdt->freq = clk_get_rate(wdt->core_clk);
470 	if (!wdt->freq) {
471 		dev_err(&pdev->dev, "get clock rate failed.\n");
472 		ret = -EINVAL;
473 		goto err_exit;
474 	}
475 
476 	wdt->wdd.min_timeout = 1;
477 	wdt->wdd.max_timeout = starfive_wdt_max_timeout(wdt);
478 	wdt->wdd.timeout = STARFIVE_WDT_DEFAULT_TIME;
479 	watchdog_init_timeout(&wdt->wdd, heartbeat, &pdev->dev);
480 	starfive_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout);
481 
482 	watchdog_set_nowayout(&wdt->wdd, nowayout);
483 	watchdog_stop_on_reboot(&wdt->wdd);
484 	watchdog_stop_on_unregister(&wdt->wdd);
485 
486 	if (early_enable) {
487 		ret = starfive_wdt_start(wdt);
488 		if (ret)
489 			goto err_exit;
490 		set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
491 	} else {
492 		starfive_wdt_stop(wdt);
493 	}
494 
495 	ret = watchdog_register_device(&wdt->wdd);
496 	if (ret)
497 		goto err_exit;
498 
499 	if (!early_enable) {
500 		if (pm_runtime_enabled(&pdev->dev)) {
501 			ret = pm_runtime_put_sync(&pdev->dev);
502 			if (ret)
503 				goto err_exit;
504 		}
505 	}
506 
507 	return 0;
508 
509 err_exit:
510 	starfive_wdt_disable_clock(wdt);
511 	pm_runtime_disable(&pdev->dev);
512 
513 	return ret;
514 }
515 
starfive_wdt_remove(struct platform_device * pdev)516 static void starfive_wdt_remove(struct platform_device *pdev)
517 {
518 	struct starfive_wdt *wdt = platform_get_drvdata(pdev);
519 
520 	starfive_wdt_stop(wdt);
521 	watchdog_unregister_device(&wdt->wdd);
522 
523 	if (pm_runtime_enabled(&pdev->dev))
524 		pm_runtime_disable(&pdev->dev);
525 	else
526 		/* disable clock without PM */
527 		starfive_wdt_disable_clock(wdt);
528 }
529 
starfive_wdt_shutdown(struct platform_device * pdev)530 static void starfive_wdt_shutdown(struct platform_device *pdev)
531 {
532 	struct starfive_wdt *wdt = platform_get_drvdata(pdev);
533 
534 	starfive_wdt_pm_stop(&wdt->wdd);
535 }
536 
starfive_wdt_suspend(struct device * dev)537 static int starfive_wdt_suspend(struct device *dev)
538 {
539 	struct starfive_wdt *wdt = dev_get_drvdata(dev);
540 
541 	/* Save watchdog state, and turn it off. */
542 	wdt->reload = starfive_wdt_get_count(wdt);
543 
544 	/* Note that WTCNT doesn't need to be saved. */
545 	starfive_wdt_stop(wdt);
546 
547 	return pm_runtime_force_suspend(dev);
548 }
549 
starfive_wdt_resume(struct device * dev)550 static int starfive_wdt_resume(struct device *dev)
551 {
552 	struct starfive_wdt *wdt = dev_get_drvdata(dev);
553 	int ret;
554 
555 	ret = pm_runtime_force_resume(dev);
556 	if (ret)
557 		return ret;
558 
559 	starfive_wdt_unlock(wdt);
560 	/* Restore watchdog state. */
561 	starfive_wdt_set_reload_count(wdt, wdt->reload);
562 	starfive_wdt_lock(wdt);
563 
564 	if (watchdog_active(&wdt->wdd))
565 		return starfive_wdt_start(wdt);
566 
567 	return 0;
568 }
569 
starfive_wdt_runtime_suspend(struct device * dev)570 static int starfive_wdt_runtime_suspend(struct device *dev)
571 {
572 	struct starfive_wdt *wdt = dev_get_drvdata(dev);
573 
574 	starfive_wdt_disable_clock(wdt);
575 
576 	return 0;
577 }
578 
starfive_wdt_runtime_resume(struct device * dev)579 static int starfive_wdt_runtime_resume(struct device *dev)
580 {
581 	struct starfive_wdt *wdt = dev_get_drvdata(dev);
582 
583 	return starfive_wdt_enable_clock(wdt);
584 }
585 
586 static const struct dev_pm_ops starfive_wdt_pm_ops = {
587 	RUNTIME_PM_OPS(starfive_wdt_runtime_suspend, starfive_wdt_runtime_resume, NULL)
588 	SYSTEM_SLEEP_PM_OPS(starfive_wdt_suspend, starfive_wdt_resume)
589 };
590 
591 static const struct of_device_id starfive_wdt_match[] = {
592 	{ .compatible = "starfive,jh7100-wdt", .data = &starfive_wdt_jh7100_variant },
593 	{ .compatible = "starfive,jh7110-wdt", .data = &starfive_wdt_jh7110_variant },
594 	{ /* sentinel */ }
595 };
596 MODULE_DEVICE_TABLE(of, starfive_wdt_match);
597 
598 static struct platform_driver starfive_wdt_driver = {
599 	.probe = starfive_wdt_probe,
600 	.remove_new = starfive_wdt_remove,
601 	.shutdown = starfive_wdt_shutdown,
602 	.driver = {
603 		.name = "starfive-wdt",
604 		.pm = pm_ptr(&starfive_wdt_pm_ops),
605 		.of_match_table = starfive_wdt_match,
606 	},
607 };
608 module_platform_driver(starfive_wdt_driver);
609 
610 MODULE_AUTHOR("Xingyu Wu <xingyu.wu@starfivetech.com>");
611 MODULE_AUTHOR("Samin Guo <samin.guo@starfivetech.com>");
612 MODULE_DESCRIPTION("StarFive Watchdog Device Driver");
613 MODULE_LICENSE("GPL");
614