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
66static bool nowayout = WATCHDOG_NOWAYOUT;
67static int heartbeat;
68static bool early_enable = STARFIVE_WDT_EARLY_ENA;
69
70module_param(heartbeat, int, 0);
71module_param(early_enable, bool, 0);
72module_param(nowayout, bool, 0);
73
74MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (default="
75 __MODULE_STRING(STARFIVE_WDT_DEFAULT_TIME) ")");
76MODULE_PARM_DESC(early_enable,
77 "Watchdog is started at boot time if set to 1, default="
78 __MODULE_STRING(STARFIVE_WDT_EARLY_ENA));
79MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
80 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
81
82struct 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
100struct 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 */
113static 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 */
131static 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
146static int starfive_wdt_enable_clock(struct starfive_wdt *wdt)
147{
148 int ret;
149
150 ret = clk_prepare_enable(clk: wdt->apb_clk);
151 if (ret)
152 return dev_err_probe(dev: wdt->wdd.parent, err: ret, fmt: "failed to enable apb clock\n");
153
154 ret = clk_prepare_enable(clk: wdt->core_clk);
155 if (ret)
156 return dev_err_probe(dev: wdt->wdd.parent, err: ret, fmt: "failed to enable core clock\n");
157
158 return 0;
159}
160
161static void starfive_wdt_disable_clock(struct starfive_wdt *wdt)
162{
163 clk_disable_unprepare(clk: wdt->core_clk);
164 clk_disable_unprepare(clk: wdt->apb_clk);
165}
166
167static inline int starfive_wdt_get_clock(struct starfive_wdt *wdt)
168{
169 struct device *dev = wdt->wdd.parent;
170
171 wdt->apb_clk = devm_clk_get(dev, id: "apb");
172 if (IS_ERR(ptr: wdt->apb_clk))
173 return dev_err_probe(dev, err: PTR_ERR(ptr: wdt->apb_clk), fmt: "failed to get apb clock\n");
174
175 wdt->core_clk = devm_clk_get(dev, id: "core");
176 if (IS_ERR(ptr: wdt->core_clk))
177 return dev_err_probe(dev, err: PTR_ERR(ptr: wdt->core_clk), fmt: "failed to get core clock\n");
178
179 return 0;
180}
181
182static inline int starfive_wdt_reset_init(struct device *dev)
183{
184 struct reset_control *rsts;
185 int ret;
186
187 rsts = devm_reset_control_array_get_exclusive(dev);
188 if (IS_ERR(ptr: rsts))
189 return dev_err_probe(dev, err: PTR_ERR(ptr: rsts), fmt: "failed to get resets\n");
190
191 ret = reset_control_deassert(rstc: rsts);
192 if (ret)
193 return dev_err_probe(dev, err: ret, fmt: "failed to deassert resets\n");
194
195 return 0;
196}
197
198static u32 starfive_wdt_ticks_to_sec(struct starfive_wdt *wdt, u32 ticks)
199{
200 return DIV_ROUND_CLOSEST(ticks, wdt->freq);
201}
202
203/* Write unlock-key to unlock. Write other value to lock. */
204static void starfive_wdt_unlock(struct starfive_wdt *wdt)
205{
206 spin_lock(lock: &wdt->lock);
207 writel(val: wdt->variant->unlock_key, addr: wdt->base + wdt->variant->unlock);
208}
209
210static void starfive_wdt_lock(struct starfive_wdt *wdt)
211{
212 writel(val: ~wdt->variant->unlock_key, addr: wdt->base + wdt->variant->unlock);
213 spin_unlock(lock: &wdt->lock);
214}
215
216/* enable watchdog interrupt to reset/reboot */
217static void starfive_wdt_enable_reset(struct starfive_wdt *wdt)
218{
219 u32 val;
220
221 val = readl(addr: wdt->base + wdt->variant->control);
222 val |= STARFIVE_WDT_RESET_EN << wdt->variant->enrst_shift;
223 writel(val, addr: wdt->base + wdt->variant->control);
224}
225
226/* interrupt status whether has been raised from the counter */
227static bool starfive_wdt_raise_irq_status(struct starfive_wdt *wdt)
228{
229 return !!readl(addr: wdt->base + wdt->variant->int_status);
230}
231
232/* waiting interrupt can be free to clear */
233static int starfive_wdt_wait_int_free(struct starfive_wdt *wdt)
234{
235 u32 value;
236
237 return readl_poll_timeout_atomic(wdt->base + wdt->variant->int_clr, value,
238 !(value & BIT(wdt->variant->intclr_ava_shift)),
239 STARFIVE_WDT_DELAY_US, STARFIVE_WDT_TIMEOUT_US);
240}
241
242/* clear interrupt signal before initialization or reload */
243static int starfive_wdt_int_clr(struct starfive_wdt *wdt)
244{
245 int ret;
246
247 if (wdt->variant->intclr_check) {
248 ret = starfive_wdt_wait_int_free(wdt);
249 if (ret)
250 return dev_err_probe(dev: wdt->wdd.parent, err: ret,
251 fmt: "watchdog is not ready to clear interrupt.\n");
252 }
253 writel(STARFIVE_WDT_INTCLR, addr: wdt->base + wdt->variant->int_clr);
254
255 return 0;
256}
257
258static inline void starfive_wdt_set_count(struct starfive_wdt *wdt, u32 val)
259{
260 writel(val, addr: wdt->base + wdt->variant->load);
261}
262
263static inline u32 starfive_wdt_get_count(struct starfive_wdt *wdt)
264{
265 return readl(addr: wdt->base + wdt->variant->value);
266}
267
268/* enable watchdog */
269static inline void starfive_wdt_enable(struct starfive_wdt *wdt)
270{
271 u32 val;
272
273 val = readl(addr: wdt->base + wdt->variant->enable);
274 val |= STARFIVE_WDT_ENABLE << wdt->variant->en_shift;
275 writel(val, addr: wdt->base + wdt->variant->enable);
276}
277
278/* disable watchdog */
279static inline void starfive_wdt_disable(struct starfive_wdt *wdt)
280{
281 u32 val;
282
283 val = readl(addr: wdt->base + wdt->variant->enable);
284 val &= ~(STARFIVE_WDT_ENABLE << wdt->variant->en_shift);
285 writel(val, addr: wdt->base + wdt->variant->enable);
286}
287
288static inline void starfive_wdt_set_reload_count(struct starfive_wdt *wdt, u32 count)
289{
290 starfive_wdt_set_count(wdt, val: count);
291
292 /* 7100 need set any value to reload register and could reload value to counter */
293 if (wdt->variant->reload)
294 writel(val: 0x1, addr: wdt->base + wdt->variant->reload);
295}
296
297static unsigned int starfive_wdt_max_timeout(struct starfive_wdt *wdt)
298{
299 if (wdt->variant->double_timeout)
300 return DIV_ROUND_UP(STARFIVE_WDT_MAXCNT, (wdt->freq / 2)) - 1;
301
302 return DIV_ROUND_UP(STARFIVE_WDT_MAXCNT, wdt->freq) - 1;
303}
304
305static unsigned int starfive_wdt_get_timeleft(struct watchdog_device *wdd)
306{
307 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
308 u32 count;
309
310 /*
311 * If the watchdog takes twice timeout and set half count value,
312 * timeleft value should add the count value before first timeout.
313 */
314 count = starfive_wdt_get_count(wdt);
315 if (wdt->variant->double_timeout && !starfive_wdt_raise_irq_status(wdt))
316 count += wdt->count;
317
318 return starfive_wdt_ticks_to_sec(wdt, ticks: count);
319}
320
321static int starfive_wdt_keepalive(struct watchdog_device *wdd)
322{
323 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
324 int ret;
325
326 starfive_wdt_unlock(wdt);
327 ret = starfive_wdt_int_clr(wdt);
328 if (ret)
329 goto exit;
330
331 starfive_wdt_set_reload_count(wdt, count: wdt->count);
332
333exit:
334 /* exit with releasing spinlock and locking registers */
335 starfive_wdt_lock(wdt);
336 return ret;
337}
338
339static int starfive_wdt_start(struct starfive_wdt *wdt)
340{
341 int ret;
342
343 starfive_wdt_unlock(wdt);
344 /* disable watchdog, to be safe */
345 starfive_wdt_disable(wdt);
346
347 starfive_wdt_enable_reset(wdt);
348 ret = starfive_wdt_int_clr(wdt);
349 if (ret)
350 goto exit;
351
352 starfive_wdt_set_count(wdt, val: wdt->count);
353 starfive_wdt_enable(wdt);
354
355exit:
356 starfive_wdt_lock(wdt);
357 return ret;
358}
359
360static void starfive_wdt_stop(struct starfive_wdt *wdt)
361{
362 starfive_wdt_unlock(wdt);
363 starfive_wdt_disable(wdt);
364 starfive_wdt_lock(wdt);
365}
366
367static int starfive_wdt_pm_start(struct watchdog_device *wdd)
368{
369 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
370 int ret = pm_runtime_get_sync(dev: wdd->parent);
371
372 if (ret < 0)
373 return ret;
374
375 return starfive_wdt_start(wdt);
376}
377
378static int starfive_wdt_pm_stop(struct watchdog_device *wdd)
379{
380 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
381
382 starfive_wdt_stop(wdt);
383 return pm_runtime_put_sync(dev: wdd->parent);
384}
385
386static int starfive_wdt_set_timeout(struct watchdog_device *wdd,
387 unsigned int timeout)
388{
389 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
390 unsigned long count = timeout * wdt->freq;
391
392 /* some watchdogs take two timeouts to reset */
393 if (wdt->variant->double_timeout)
394 count /= 2;
395
396 wdt->count = count;
397 wdd->timeout = timeout;
398
399 starfive_wdt_unlock(wdt);
400 starfive_wdt_disable(wdt);
401 starfive_wdt_set_reload_count(wdt, count: wdt->count);
402 starfive_wdt_enable(wdt);
403 starfive_wdt_lock(wdt);
404
405 return 0;
406}
407
408#define STARFIVE_WDT_OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
409
410static const struct watchdog_info starfive_wdt_info = {
411 .options = STARFIVE_WDT_OPTIONS,
412 .identity = "StarFive Watchdog",
413};
414
415static const struct watchdog_ops starfive_wdt_ops = {
416 .owner = THIS_MODULE,
417 .start = starfive_wdt_pm_start,
418 .stop = starfive_wdt_pm_stop,
419 .ping = starfive_wdt_keepalive,
420 .set_timeout = starfive_wdt_set_timeout,
421 .get_timeleft = starfive_wdt_get_timeleft,
422};
423
424static int starfive_wdt_probe(struct platform_device *pdev)
425{
426 struct starfive_wdt *wdt;
427 int ret;
428
429 wdt = devm_kzalloc(dev: &pdev->dev, size: sizeof(*wdt), GFP_KERNEL);
430 if (!wdt)
431 return -ENOMEM;
432
433 wdt->base = devm_platform_ioremap_resource(pdev, index: 0);
434 if (IS_ERR(ptr: wdt->base))
435 return dev_err_probe(dev: &pdev->dev, err: PTR_ERR(ptr: wdt->base), fmt: "error mapping registers\n");
436
437 wdt->wdd.parent = &pdev->dev;
438 ret = starfive_wdt_get_clock(wdt);
439 if (ret)
440 return ret;
441
442 platform_set_drvdata(pdev, data: wdt);
443 pm_runtime_enable(dev: &pdev->dev);
444 if (pm_runtime_enabled(dev: &pdev->dev)) {
445 ret = pm_runtime_get_sync(dev: &pdev->dev);
446 if (ret < 0)
447 return ret;
448 } else {
449 /* runtime PM is disabled but clocks need to be enabled */
450 ret = starfive_wdt_enable_clock(wdt);
451 if (ret)
452 return ret;
453 }
454
455 ret = starfive_wdt_reset_init(dev: &pdev->dev);
456 if (ret)
457 goto err_exit;
458
459 watchdog_set_drvdata(wdd: &wdt->wdd, data: wdt);
460 wdt->wdd.info = &starfive_wdt_info;
461 wdt->wdd.ops = &starfive_wdt_ops;
462 wdt->variant = of_device_get_match_data(dev: &pdev->dev);
463 spin_lock_init(&wdt->lock);
464
465 wdt->freq = clk_get_rate(clk: wdt->core_clk);
466 if (!wdt->freq) {
467 dev_err(&pdev->dev, "get clock rate failed.\n");
468 ret = -EINVAL;
469 goto err_exit;
470 }
471
472 wdt->wdd.min_timeout = 1;
473 wdt->wdd.max_timeout = starfive_wdt_max_timeout(wdt);
474 wdt->wdd.timeout = STARFIVE_WDT_DEFAULT_TIME;
475 watchdog_init_timeout(wdd: &wdt->wdd, timeout_parm: heartbeat, dev: &pdev->dev);
476 starfive_wdt_set_timeout(wdd: &wdt->wdd, timeout: wdt->wdd.timeout);
477
478 watchdog_set_nowayout(wdd: &wdt->wdd, nowayout);
479 watchdog_stop_on_reboot(wdd: &wdt->wdd);
480 watchdog_stop_on_unregister(wdd: &wdt->wdd);
481
482 if (early_enable) {
483 ret = starfive_wdt_start(wdt);
484 if (ret)
485 goto err_exit;
486 set_bit(WDOG_HW_RUNNING, addr: &wdt->wdd.status);
487 } else {
488 starfive_wdt_stop(wdt);
489 }
490
491 ret = watchdog_register_device(&wdt->wdd);
492 if (ret)
493 goto err_exit;
494
495 if (!early_enable)
496 pm_runtime_put_sync(dev: &pdev->dev);
497
498 return 0;
499
500err_exit:
501 starfive_wdt_disable_clock(wdt);
502 pm_runtime_disable(dev: &pdev->dev);
503
504 return ret;
505}
506
507static int starfive_wdt_remove(struct platform_device *pdev)
508{
509 struct starfive_wdt *wdt = platform_get_drvdata(pdev);
510
511 starfive_wdt_stop(wdt);
512 watchdog_unregister_device(&wdt->wdd);
513
514 if (pm_runtime_enabled(dev: &pdev->dev))
515 pm_runtime_disable(dev: &pdev->dev);
516 else
517 /* disable clock without PM */
518 starfive_wdt_disable_clock(wdt);
519
520 return 0;
521}
522
523static void starfive_wdt_shutdown(struct platform_device *pdev)
524{
525 struct starfive_wdt *wdt = platform_get_drvdata(pdev);
526
527 starfive_wdt_pm_stop(wdd: &wdt->wdd);
528}
529
530static int starfive_wdt_suspend(struct device *dev)
531{
532 struct starfive_wdt *wdt = dev_get_drvdata(dev);
533
534 /* Save watchdog state, and turn it off. */
535 wdt->reload = starfive_wdt_get_count(wdt);
536
537 /* Note that WTCNT doesn't need to be saved. */
538 starfive_wdt_stop(wdt);
539
540 return pm_runtime_force_suspend(dev);
541}
542
543static int starfive_wdt_resume(struct device *dev)
544{
545 struct starfive_wdt *wdt = dev_get_drvdata(dev);
546 int ret;
547
548 ret = pm_runtime_force_resume(dev);
549 if (ret)
550 return ret;
551
552 starfive_wdt_unlock(wdt);
553 /* Restore watchdog state. */
554 starfive_wdt_set_reload_count(wdt, count: wdt->reload);
555 starfive_wdt_lock(wdt);
556
557 return starfive_wdt_start(wdt);
558}
559
560static int starfive_wdt_runtime_suspend(struct device *dev)
561{
562 struct starfive_wdt *wdt = dev_get_drvdata(dev);
563
564 starfive_wdt_disable_clock(wdt);
565
566 return 0;
567}
568
569static int starfive_wdt_runtime_resume(struct device *dev)
570{
571 struct starfive_wdt *wdt = dev_get_drvdata(dev);
572
573 return starfive_wdt_enable_clock(wdt);
574}
575
576static const struct dev_pm_ops starfive_wdt_pm_ops = {
577 RUNTIME_PM_OPS(starfive_wdt_runtime_suspend, starfive_wdt_runtime_resume, NULL)
578 SYSTEM_SLEEP_PM_OPS(starfive_wdt_suspend, starfive_wdt_resume)
579};
580
581static const struct of_device_id starfive_wdt_match[] = {
582 { .compatible = "starfive,jh7100-wdt", .data = &starfive_wdt_jh7100_variant },
583 { .compatible = "starfive,jh7110-wdt", .data = &starfive_wdt_jh7110_variant },
584 { /* sentinel */ }
585};
586MODULE_DEVICE_TABLE(of, starfive_wdt_match);
587
588static struct platform_driver starfive_wdt_driver = {
589 .probe = starfive_wdt_probe,
590 .remove = starfive_wdt_remove,
591 .shutdown = starfive_wdt_shutdown,
592 .driver = {
593 .name = "starfive-wdt",
594 .pm = pm_ptr(&starfive_wdt_pm_ops),
595 .of_match_table = starfive_wdt_match,
596 },
597};
598module_platform_driver(starfive_wdt_driver);
599
600MODULE_AUTHOR("Xingyu Wu <xingyu.wu@starfivetech.com>");
601MODULE_AUTHOR("Samin Guo <samin.guo@starfivetech.com>");
602MODULE_DESCRIPTION("StarFive Watchdog Device Driver");
603MODULE_LICENSE("GPL");
604

source code of linux/drivers/watchdog/starfive-wdt.c