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 __acquires(&wdt->lock)
206{
207 spin_lock(lock: &wdt->lock);
208 writel(val: wdt->variant->unlock_key, addr: wdt->base + wdt->variant->unlock);
209}
210
211static void starfive_wdt_lock(struct starfive_wdt *wdt)
212 __releases(&wdt->lock)
213{
214 writel(val: ~wdt->variant->unlock_key, addr: wdt->base + wdt->variant->unlock);
215 spin_unlock(lock: &wdt->lock);
216}
217
218/* enable watchdog interrupt to reset/reboot */
219static void starfive_wdt_enable_reset(struct starfive_wdt *wdt)
220{
221 u32 val;
222
223 val = readl(addr: wdt->base + wdt->variant->control);
224 val |= STARFIVE_WDT_RESET_EN << wdt->variant->enrst_shift;
225 writel(val, addr: wdt->base + wdt->variant->control);
226}
227
228/* interrupt status whether has been raised from the counter */
229static bool starfive_wdt_raise_irq_status(struct starfive_wdt *wdt)
230{
231 return !!readl(addr: wdt->base + wdt->variant->int_status);
232}
233
234/* waiting interrupt can be free to clear */
235static int starfive_wdt_wait_int_free(struct starfive_wdt *wdt)
236{
237 u32 value;
238
239 return readl_poll_timeout_atomic(wdt->base + wdt->variant->int_clr, value,
240 !(value & BIT(wdt->variant->intclr_ava_shift)),
241 STARFIVE_WDT_DELAY_US, STARFIVE_WDT_TIMEOUT_US);
242}
243
244/* clear interrupt signal before initialization or reload */
245static int starfive_wdt_int_clr(struct starfive_wdt *wdt)
246{
247 int ret;
248
249 if (wdt->variant->intclr_check) {
250 ret = starfive_wdt_wait_int_free(wdt);
251 if (ret)
252 return dev_err_probe(dev: wdt->wdd.parent, err: ret,
253 fmt: "watchdog is not ready to clear interrupt.\n");
254 }
255 writel(STARFIVE_WDT_INTCLR, addr: wdt->base + wdt->variant->int_clr);
256
257 return 0;
258}
259
260static inline void starfive_wdt_set_count(struct starfive_wdt *wdt, u32 val)
261{
262 writel(val, addr: wdt->base + wdt->variant->load);
263}
264
265static inline u32 starfive_wdt_get_count(struct starfive_wdt *wdt)
266{
267 return readl(addr: wdt->base + wdt->variant->value);
268}
269
270/* enable watchdog */
271static inline void starfive_wdt_enable(struct starfive_wdt *wdt)
272{
273 u32 val;
274
275 val = readl(addr: wdt->base + wdt->variant->enable);
276 val |= STARFIVE_WDT_ENABLE << wdt->variant->en_shift;
277 writel(val, addr: wdt->base + wdt->variant->enable);
278}
279
280/* disable watchdog */
281static inline void starfive_wdt_disable(struct starfive_wdt *wdt)
282{
283 u32 val;
284
285 val = readl(addr: wdt->base + wdt->variant->enable);
286 val &= ~(STARFIVE_WDT_ENABLE << wdt->variant->en_shift);
287 writel(val, addr: wdt->base + wdt->variant->enable);
288}
289
290static inline void starfive_wdt_set_reload_count(struct starfive_wdt *wdt, u32 count)
291{
292 starfive_wdt_set_count(wdt, val: count);
293
294 /* 7100 need set any value to reload register and could reload value to counter */
295 if (wdt->variant->reload)
296 writel(val: 0x1, addr: wdt->base + wdt->variant->reload);
297}
298
299static unsigned int starfive_wdt_max_timeout(struct starfive_wdt *wdt)
300{
301 if (wdt->variant->double_timeout)
302 return DIV_ROUND_UP(STARFIVE_WDT_MAXCNT, (wdt->freq / 2)) - 1;
303
304 return DIV_ROUND_UP(STARFIVE_WDT_MAXCNT, wdt->freq) - 1;
305}
306
307static unsigned int starfive_wdt_get_timeleft(struct watchdog_device *wdd)
308{
309 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
310 u32 count;
311
312 /*
313 * If the watchdog takes twice timeout and set half count value,
314 * timeleft value should add the count value before first timeout.
315 */
316 count = starfive_wdt_get_count(wdt);
317 if (wdt->variant->double_timeout && !starfive_wdt_raise_irq_status(wdt))
318 count += wdt->count;
319
320 return starfive_wdt_ticks_to_sec(wdt, ticks: count);
321}
322
323static int starfive_wdt_keepalive(struct watchdog_device *wdd)
324{
325 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
326 int ret;
327
328 starfive_wdt_unlock(wdt);
329 ret = starfive_wdt_int_clr(wdt);
330 if (ret)
331 goto exit;
332
333 starfive_wdt_set_reload_count(wdt, count: wdt->count);
334
335exit:
336 /* exit with releasing spinlock and locking registers */
337 starfive_wdt_lock(wdt);
338 return ret;
339}
340
341static int starfive_wdt_start(struct starfive_wdt *wdt)
342{
343 int ret;
344
345 starfive_wdt_unlock(wdt);
346 /* disable watchdog, to be safe */
347 starfive_wdt_disable(wdt);
348
349 starfive_wdt_enable_reset(wdt);
350 ret = starfive_wdt_int_clr(wdt);
351 if (ret)
352 goto exit;
353
354 starfive_wdt_set_count(wdt, val: wdt->count);
355 starfive_wdt_enable(wdt);
356
357exit:
358 starfive_wdt_lock(wdt);
359 return ret;
360}
361
362static void starfive_wdt_stop(struct starfive_wdt *wdt)
363{
364 starfive_wdt_unlock(wdt);
365 starfive_wdt_disable(wdt);
366 starfive_wdt_lock(wdt);
367}
368
369static int starfive_wdt_pm_start(struct watchdog_device *wdd)
370{
371 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
372 int ret = pm_runtime_get_sync(dev: wdd->parent);
373
374 if (ret < 0)
375 return ret;
376
377 return starfive_wdt_start(wdt);
378}
379
380static int starfive_wdt_pm_stop(struct watchdog_device *wdd)
381{
382 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
383
384 starfive_wdt_stop(wdt);
385 return pm_runtime_put_sync(dev: wdd->parent);
386}
387
388static int starfive_wdt_set_timeout(struct watchdog_device *wdd,
389 unsigned int timeout)
390{
391 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
392 unsigned long count = timeout * wdt->freq;
393
394 /* some watchdogs take two timeouts to reset */
395 if (wdt->variant->double_timeout)
396 count /= 2;
397
398 wdt->count = count;
399 wdd->timeout = timeout;
400
401 starfive_wdt_unlock(wdt);
402 starfive_wdt_disable(wdt);
403 starfive_wdt_set_reload_count(wdt, count: wdt->count);
404 starfive_wdt_enable(wdt);
405 starfive_wdt_lock(wdt);
406
407 return 0;
408}
409
410#define STARFIVE_WDT_OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
411
412static const struct watchdog_info starfive_wdt_info = {
413 .options = STARFIVE_WDT_OPTIONS,
414 .identity = "StarFive Watchdog",
415};
416
417static const struct watchdog_ops starfive_wdt_ops = {
418 .owner = THIS_MODULE,
419 .start = starfive_wdt_pm_start,
420 .stop = starfive_wdt_pm_stop,
421 .ping = starfive_wdt_keepalive,
422 .set_timeout = starfive_wdt_set_timeout,
423 .get_timeleft = starfive_wdt_get_timeleft,
424};
425
426static int starfive_wdt_probe(struct platform_device *pdev)
427{
428 struct starfive_wdt *wdt;
429 int ret;
430
431 wdt = devm_kzalloc(dev: &pdev->dev, size: sizeof(*wdt), GFP_KERNEL);
432 if (!wdt)
433 return -ENOMEM;
434
435 wdt->base = devm_platform_ioremap_resource(pdev, index: 0);
436 if (IS_ERR(ptr: wdt->base))
437 return dev_err_probe(dev: &pdev->dev, err: PTR_ERR(ptr: wdt->base), fmt: "error mapping registers\n");
438
439 wdt->wdd.parent = &pdev->dev;
440 ret = starfive_wdt_get_clock(wdt);
441 if (ret)
442 return ret;
443
444 platform_set_drvdata(pdev, data: wdt);
445 pm_runtime_enable(dev: &pdev->dev);
446 if (pm_runtime_enabled(dev: &pdev->dev)) {
447 ret = pm_runtime_get_sync(dev: &pdev->dev);
448 if (ret < 0)
449 return ret;
450 } else {
451 /* runtime PM is disabled but clocks need to be enabled */
452 ret = starfive_wdt_enable_clock(wdt);
453 if (ret)
454 return ret;
455 }
456
457 ret = starfive_wdt_reset_init(dev: &pdev->dev);
458 if (ret)
459 goto err_exit;
460
461 watchdog_set_drvdata(wdd: &wdt->wdd, data: wdt);
462 wdt->wdd.info = &starfive_wdt_info;
463 wdt->wdd.ops = &starfive_wdt_ops;
464 wdt->variant = of_device_get_match_data(dev: &pdev->dev);
465 spin_lock_init(&wdt->lock);
466
467 wdt->freq = clk_get_rate(clk: wdt->core_clk);
468 if (!wdt->freq) {
469 dev_err(&pdev->dev, "get clock rate failed.\n");
470 ret = -EINVAL;
471 goto err_exit;
472 }
473
474 wdt->wdd.min_timeout = 1;
475 wdt->wdd.max_timeout = starfive_wdt_max_timeout(wdt);
476 wdt->wdd.timeout = STARFIVE_WDT_DEFAULT_TIME;
477 watchdog_init_timeout(wdd: &wdt->wdd, timeout_parm: heartbeat, dev: &pdev->dev);
478 starfive_wdt_set_timeout(wdd: &wdt->wdd, timeout: wdt->wdd.timeout);
479
480 watchdog_set_nowayout(wdd: &wdt->wdd, nowayout);
481 watchdog_stop_on_reboot(wdd: &wdt->wdd);
482 watchdog_stop_on_unregister(wdd: &wdt->wdd);
483
484 if (early_enable) {
485 ret = starfive_wdt_start(wdt);
486 if (ret)
487 goto err_exit;
488 set_bit(WDOG_HW_RUNNING, addr: &wdt->wdd.status);
489 } else {
490 starfive_wdt_stop(wdt);
491 }
492
493 ret = watchdog_register_device(&wdt->wdd);
494 if (ret)
495 goto err_exit;
496
497 if (!early_enable) {
498 if (pm_runtime_enabled(dev: &pdev->dev)) {
499 ret = pm_runtime_put_sync(dev: &pdev->dev);
500 if (ret)
501 goto err_exit;
502 }
503 }
504
505 return 0;
506
507err_exit:
508 starfive_wdt_disable_clock(wdt);
509 pm_runtime_disable(dev: &pdev->dev);
510
511 return ret;
512}
513
514static void starfive_wdt_remove(struct platform_device *pdev)
515{
516 struct starfive_wdt *wdt = platform_get_drvdata(pdev);
517
518 starfive_wdt_stop(wdt);
519 watchdog_unregister_device(&wdt->wdd);
520
521 if (pm_runtime_enabled(dev: &pdev->dev))
522 pm_runtime_disable(dev: &pdev->dev);
523 else
524 /* disable clock without PM */
525 starfive_wdt_disable_clock(wdt);
526}
527
528static void starfive_wdt_shutdown(struct platform_device *pdev)
529{
530 struct starfive_wdt *wdt = platform_get_drvdata(pdev);
531
532 starfive_wdt_pm_stop(wdd: &wdt->wdd);
533}
534
535static int starfive_wdt_suspend(struct device *dev)
536{
537 struct starfive_wdt *wdt = dev_get_drvdata(dev);
538
539 /* Save watchdog state, and turn it off. */
540 wdt->reload = starfive_wdt_get_count(wdt);
541
542 /* Note that WTCNT doesn't need to be saved. */
543 starfive_wdt_stop(wdt);
544
545 return pm_runtime_force_suspend(dev);
546}
547
548static int starfive_wdt_resume(struct device *dev)
549{
550 struct starfive_wdt *wdt = dev_get_drvdata(dev);
551 int ret;
552
553 ret = pm_runtime_force_resume(dev);
554 if (ret)
555 return ret;
556
557 starfive_wdt_unlock(wdt);
558 /* Restore watchdog state. */
559 starfive_wdt_set_reload_count(wdt, count: wdt->reload);
560 starfive_wdt_lock(wdt);
561
562 if (watchdog_active(wdd: &wdt->wdd))
563 return starfive_wdt_start(wdt);
564
565 return 0;
566}
567
568static int starfive_wdt_runtime_suspend(struct device *dev)
569{
570 struct starfive_wdt *wdt = dev_get_drvdata(dev);
571
572 starfive_wdt_disable_clock(wdt);
573
574 return 0;
575}
576
577static int starfive_wdt_runtime_resume(struct device *dev)
578{
579 struct starfive_wdt *wdt = dev_get_drvdata(dev);
580
581 return starfive_wdt_enable_clock(wdt);
582}
583
584static const struct dev_pm_ops starfive_wdt_pm_ops = {
585 RUNTIME_PM_OPS(starfive_wdt_runtime_suspend, starfive_wdt_runtime_resume, NULL)
586 SYSTEM_SLEEP_PM_OPS(starfive_wdt_suspend, starfive_wdt_resume)
587};
588
589static const struct of_device_id starfive_wdt_match[] = {
590 { .compatible = "starfive,jh7100-wdt", .data = &starfive_wdt_jh7100_variant },
591 { .compatible = "starfive,jh7110-wdt", .data = &starfive_wdt_jh7110_variant },
592 { /* sentinel */ }
593};
594MODULE_DEVICE_TABLE(of, starfive_wdt_match);
595
596static struct platform_driver starfive_wdt_driver = {
597 .probe = starfive_wdt_probe,
598 .remove_new = starfive_wdt_remove,
599 .shutdown = starfive_wdt_shutdown,
600 .driver = {
601 .name = "starfive-wdt",
602 .pm = pm_ptr(&starfive_wdt_pm_ops),
603 .of_match_table = starfive_wdt_match,
604 },
605};
606module_platform_driver(starfive_wdt_driver);
607
608MODULE_AUTHOR("Xingyu Wu <xingyu.wu@starfivetech.com>");
609MODULE_AUTHOR("Samin Guo <samin.guo@starfivetech.com>");
610MODULE_DESCRIPTION("StarFive Watchdog Device Driver");
611MODULE_LICENSE("GPL");
612

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