Linux 6.7-rc7
[linux-modified.git] / drivers / watchdog / starfive-wdt.c
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
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                 return dev_err_probe(wdt->wdd.parent, ret, "failed to enable core clock\n");
157
158         return 0;
159 }
160
161 static void starfive_wdt_disable_clock(struct starfive_wdt *wdt)
162 {
163         clk_disable_unprepare(wdt->core_clk);
164         clk_disable_unprepare(wdt->apb_clk);
165 }
166
167 static 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, "apb");
172         if (IS_ERR(wdt->apb_clk))
173                 return dev_err_probe(dev, PTR_ERR(wdt->apb_clk), "failed to get apb clock\n");
174
175         wdt->core_clk = devm_clk_get(dev, "core");
176         if (IS_ERR(wdt->core_clk))
177                 return dev_err_probe(dev, PTR_ERR(wdt->core_clk), "failed to get core clock\n");
178
179         return 0;
180 }
181
182 static 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(rsts))
189                 return dev_err_probe(dev, PTR_ERR(rsts), "failed to get resets\n");
190
191         ret = reset_control_deassert(rsts);
192         if (ret)
193                 return dev_err_probe(dev, ret, "failed to deassert resets\n");
194
195         return 0;
196 }
197
198 static 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. */
204 static void starfive_wdt_unlock(struct starfive_wdt *wdt)
205 {
206         spin_lock(&wdt->lock);
207         writel(wdt->variant->unlock_key, wdt->base + wdt->variant->unlock);
208 }
209
210 static void starfive_wdt_lock(struct starfive_wdt *wdt)
211 {
212         writel(~wdt->variant->unlock_key, wdt->base + wdt->variant->unlock);
213         spin_unlock(&wdt->lock);
214 }
215
216 /* enable watchdog interrupt to reset/reboot */
217 static void starfive_wdt_enable_reset(struct starfive_wdt *wdt)
218 {
219         u32 val;
220
221         val = readl(wdt->base + wdt->variant->control);
222         val |= STARFIVE_WDT_RESET_EN << wdt->variant->enrst_shift;
223         writel(val, wdt->base + wdt->variant->control);
224 }
225
226 /* interrupt status whether has been raised from the counter */
227 static bool starfive_wdt_raise_irq_status(struct starfive_wdt *wdt)
228 {
229         return !!readl(wdt->base + wdt->variant->int_status);
230 }
231
232 /* waiting interrupt can be free to clear */
233 static 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 */
243 static 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(wdt->wdd.parent, ret,
251                                              "watchdog is not ready to clear interrupt.\n");
252         }
253         writel(STARFIVE_WDT_INTCLR, wdt->base + wdt->variant->int_clr);
254
255         return 0;
256 }
257
258 static inline void starfive_wdt_set_count(struct starfive_wdt *wdt, u32 val)
259 {
260         writel(val, wdt->base + wdt->variant->load);
261 }
262
263 static inline u32 starfive_wdt_get_count(struct starfive_wdt *wdt)
264 {
265         return readl(wdt->base + wdt->variant->value);
266 }
267
268 /* enable watchdog */
269 static inline void starfive_wdt_enable(struct starfive_wdt *wdt)
270 {
271         u32 val;
272
273         val = readl(wdt->base + wdt->variant->enable);
274         val |= STARFIVE_WDT_ENABLE << wdt->variant->en_shift;
275         writel(val, wdt->base + wdt->variant->enable);
276 }
277
278 /* disable watchdog */
279 static inline void starfive_wdt_disable(struct starfive_wdt *wdt)
280 {
281         u32 val;
282
283         val = readl(wdt->base + wdt->variant->enable);
284         val &= ~(STARFIVE_WDT_ENABLE << wdt->variant->en_shift);
285         writel(val, wdt->base + wdt->variant->enable);
286 }
287
288 static inline void starfive_wdt_set_reload_count(struct starfive_wdt *wdt, u32 count)
289 {
290         starfive_wdt_set_count(wdt, count);
291
292         /* 7100 need set any value to reload register and could reload value to counter */
293         if (wdt->variant->reload)
294                 writel(0x1, wdt->base + wdt->variant->reload);
295 }
296
297 static 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
305 static 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, count);
319 }
320
321 static 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, wdt->count);
332
333 exit:
334         /* exit with releasing spinlock and locking registers */
335         starfive_wdt_lock(wdt);
336         return ret;
337 }
338
339 static 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, wdt->count);
353         starfive_wdt_enable(wdt);
354
355 exit:
356         starfive_wdt_lock(wdt);
357         return ret;
358 }
359
360 static 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
367 static 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(wdd->parent);
371
372         if (ret < 0)
373                 return ret;
374
375         return starfive_wdt_start(wdt);
376 }
377
378 static 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(wdd->parent);
384 }
385
386 static 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, 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
410 static const struct watchdog_info starfive_wdt_info = {
411         .options = STARFIVE_WDT_OPTIONS,
412         .identity = "StarFive Watchdog",
413 };
414
415 static 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
424 static int starfive_wdt_probe(struct platform_device *pdev)
425 {
426         struct starfive_wdt *wdt;
427         int ret;
428
429         wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
430         if (!wdt)
431                 return -ENOMEM;
432
433         wdt->base = devm_platform_ioremap_resource(pdev, 0);
434         if (IS_ERR(wdt->base))
435                 return dev_err_probe(&pdev->dev, PTR_ERR(wdt->base), "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, wdt);
443         pm_runtime_enable(&pdev->dev);
444         if (pm_runtime_enabled(&pdev->dev)) {
445                 ret = pm_runtime_get_sync(&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(&pdev->dev);
456         if (ret)
457                 goto err_exit;
458
459         watchdog_set_drvdata(&wdt->wdd, wdt);
460         wdt->wdd.info = &starfive_wdt_info;
461         wdt->wdd.ops = &starfive_wdt_ops;
462         wdt->variant = of_device_get_match_data(&pdev->dev);
463         spin_lock_init(&wdt->lock);
464
465         wdt->freq = clk_get_rate(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(&wdt->wdd, heartbeat, &pdev->dev);
476         starfive_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout);
477
478         watchdog_set_nowayout(&wdt->wdd, nowayout);
479         watchdog_stop_on_reboot(&wdt->wdd);
480         watchdog_stop_on_unregister(&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, &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(&pdev->dev);
497
498         return 0;
499
500 err_exit:
501         starfive_wdt_disable_clock(wdt);
502         pm_runtime_disable(&pdev->dev);
503
504         return ret;
505 }
506
507 static 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(&pdev->dev))
515                 pm_runtime_disable(&pdev->dev);
516         else
517                 /* disable clock without PM */
518                 starfive_wdt_disable_clock(wdt);
519
520         return 0;
521 }
522
523 static void starfive_wdt_shutdown(struct platform_device *pdev)
524 {
525         struct starfive_wdt *wdt = platform_get_drvdata(pdev);
526
527         starfive_wdt_pm_stop(&wdt->wdd);
528 }
529
530 static 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
543 static 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, wdt->reload);
555         starfive_wdt_lock(wdt);
556
557         return starfive_wdt_start(wdt);
558 }
559
560 static 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
569 static 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
576 static 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
581 static 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 };
586 MODULE_DEVICE_TABLE(of, starfive_wdt_match);
587
588 static 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 };
598 module_platform_driver(starfive_wdt_driver);
599
600 MODULE_AUTHOR("Xingyu Wu <xingyu.wu@starfivetech.com>");
601 MODULE_AUTHOR("Samin Guo <samin.guo@starfivetech.com>");
602 MODULE_DESCRIPTION("StarFive Watchdog Device Driver");
603 MODULE_LICENSE("GPL");