1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright �� 2014-2023 Broadcom
4 */
5
6#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
7
8#include <linux/clk.h>
9#include <linux/device.h>
10#include <linux/err.h>
11#include <linux/init.h>
12#include <linux/interrupt.h>
13#include <linux/io.h>
14#include <linux/irqreturn.h>
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/of.h>
18#include <linux/platform_device.h>
19#include <linux/pm.h>
20#include <linux/pm_wakeup.h>
21#include <linux/reboot.h>
22#include <linux/rtc.h>
23#include <linux/stat.h>
24#include <linux/suspend.h>
25
26struct brcmstb_waketmr {
27	struct rtc_device *rtc;
28	struct device *dev;
29	void __iomem *base;
30	unsigned int wake_irq;
31	unsigned int alarm_irq;
32	struct notifier_block reboot_notifier;
33	struct clk *clk;
34	u32 rate;
35	unsigned long rtc_alarm;
36	bool alarm_en;
37	bool alarm_expired;
38};
39
40#define BRCMSTB_WKTMR_EVENT		0x00
41#define  WKTMR_ALARM_EVENT		BIT(0)
42#define BRCMSTB_WKTMR_COUNTER		0x04
43#define BRCMSTB_WKTMR_ALARM		0x08
44#define BRCMSTB_WKTMR_PRESCALER		0x0C
45#define BRCMSTB_WKTMR_PRESCALER_VAL	0x10
46
47#define BRCMSTB_WKTMR_DEFAULT_FREQ	27000000
48
49static inline bool brcmstb_waketmr_is_pending(struct brcmstb_waketmr *timer)
50{
51	u32 reg;
52
53	reg = readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
54	return !!(reg & WKTMR_ALARM_EVENT);
55}
56
57static inline void brcmstb_waketmr_clear_alarm(struct brcmstb_waketmr *timer)
58{
59	u32 reg;
60
61	if (timer->alarm_en && timer->alarm_irq)
62		disable_irq(timer->alarm_irq);
63	timer->alarm_en = false;
64	reg = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
65	writel_relaxed(reg - 1, timer->base + BRCMSTB_WKTMR_ALARM);
66	writel_relaxed(WKTMR_ALARM_EVENT, timer->base + BRCMSTB_WKTMR_EVENT);
67	(void)readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
68	if (timer->alarm_expired) {
69		timer->alarm_expired = false;
70		/* maintain call balance */
71		enable_irq(timer->alarm_irq);
72	}
73}
74
75static void brcmstb_waketmr_set_alarm(struct brcmstb_waketmr *timer,
76				      unsigned int secs)
77{
78	unsigned int now;
79
80	brcmstb_waketmr_clear_alarm(timer);
81
82	/* Make sure we are actually counting in seconds */
83	writel_relaxed(timer->rate, timer->base + BRCMSTB_WKTMR_PRESCALER);
84
85	writel_relaxed(secs, timer->base + BRCMSTB_WKTMR_ALARM);
86	now = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
87
88	while ((int)(secs - now) <= 0 &&
89		!brcmstb_waketmr_is_pending(timer)) {
90		secs = now + 1;
91		writel_relaxed(secs, timer->base + BRCMSTB_WKTMR_ALARM);
92		now = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
93	}
94}
95
96static irqreturn_t brcmstb_waketmr_irq(int irq, void *data)
97{
98	struct brcmstb_waketmr *timer = data;
99
100	if (!timer->alarm_irq)
101		pm_wakeup_event(timer->dev, 0);
102	return IRQ_HANDLED;
103}
104
105static irqreturn_t brcmstb_alarm_irq(int irq, void *data)
106{
107	struct brcmstb_waketmr *timer = data;
108
109	/* Ignore spurious interrupts */
110	if (!brcmstb_waketmr_is_pending(timer))
111		return IRQ_HANDLED;
112
113	if (timer->alarm_en) {
114		if (device_may_wakeup(timer->dev)) {
115			disable_irq_nosync(irq);
116			timer->alarm_expired = true;
117		} else {
118			writel_relaxed(WKTMR_ALARM_EVENT,
119				       timer->base + BRCMSTB_WKTMR_EVENT);
120		}
121		rtc_update_irq(timer->rtc, 1, RTC_IRQF | RTC_AF);
122	} else {
123		writel_relaxed(WKTMR_ALARM_EVENT,
124			       timer->base + BRCMSTB_WKTMR_EVENT);
125	}
126
127	return IRQ_HANDLED;
128}
129
130struct wktmr_time {
131	u32 sec;
132	u32 pre;
133};
134
135static void wktmr_read(struct brcmstb_waketmr *timer,
136		       struct wktmr_time *t)
137{
138	u32 tmp;
139
140	do {
141		t->sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
142		tmp = readl_relaxed(timer->base + BRCMSTB_WKTMR_PRESCALER_VAL);
143	} while (tmp >= timer->rate);
144
145	t->pre = timer->rate - tmp;
146}
147
148static int brcmstb_waketmr_prepare_suspend(struct brcmstb_waketmr *timer)
149{
150	struct device *dev = timer->dev;
151	int ret;
152
153	if (device_may_wakeup(dev)) {
154		ret = enable_irq_wake(timer->wake_irq);
155		if (ret) {
156			dev_err(dev, "failed to enable wake-up interrupt\n");
157			return ret;
158		}
159		if (timer->alarm_en && timer->alarm_irq) {
160			ret = enable_irq_wake(timer->alarm_irq);
161			if (ret) {
162				dev_err(dev, "failed to enable rtc interrupt\n");
163				disable_irq_wake(timer->wake_irq);
164				return ret;
165			}
166		}
167	}
168
169	return 0;
170}
171
172/* If enabled as a wakeup-source, arm the timer when powering off */
173static int brcmstb_waketmr_reboot(struct notifier_block *nb,
174		unsigned long action, void *data)
175{
176	struct brcmstb_waketmr *timer;
177
178	timer = container_of(nb, struct brcmstb_waketmr, reboot_notifier);
179
180	/* Set timer for cold boot */
181	if (action == SYS_POWER_OFF)
182		brcmstb_waketmr_prepare_suspend(timer);
183
184	return NOTIFY_DONE;
185}
186
187static int brcmstb_waketmr_gettime(struct device *dev,
188				   struct rtc_time *tm)
189{
190	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
191	struct wktmr_time now;
192
193	wktmr_read(timer, &now);
194
195	rtc_time64_to_tm(now.sec, tm);
196
197	return 0;
198}
199
200static int brcmstb_waketmr_settime(struct device *dev,
201				   struct rtc_time *tm)
202{
203	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
204	time64_t sec;
205
206	sec = rtc_tm_to_time64(tm);
207
208	writel_relaxed(sec, timer->base + BRCMSTB_WKTMR_COUNTER);
209
210	return 0;
211}
212
213static int brcmstb_waketmr_getalarm(struct device *dev,
214				    struct rtc_wkalrm *alarm)
215{
216	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
217
218	alarm->enabled = timer->alarm_en;
219	rtc_time64_to_tm(timer->rtc_alarm, &alarm->time);
220
221	alarm->pending = brcmstb_waketmr_is_pending(timer);
222
223	return 0;
224}
225
226static int brcmstb_waketmr_alarm_enable(struct device *dev,
227					unsigned int enabled)
228{
229	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
230
231	if (enabled && !timer->alarm_en) {
232		if ((int)(readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER) -
233		    readl_relaxed(timer->base + BRCMSTB_WKTMR_ALARM)) >= 0 &&
234		    !brcmstb_waketmr_is_pending(timer))
235			return -EINVAL;
236		timer->alarm_en = true;
237		if (timer->alarm_irq) {
238			if (timer->alarm_expired) {
239				timer->alarm_expired = false;
240				/* maintain call balance */
241				enable_irq(timer->alarm_irq);
242			}
243			enable_irq(timer->alarm_irq);
244		}
245	} else if (!enabled && timer->alarm_en) {
246		if (timer->alarm_irq)
247			disable_irq(timer->alarm_irq);
248		timer->alarm_en = false;
249	}
250
251	return 0;
252}
253
254static int brcmstb_waketmr_setalarm(struct device *dev,
255				     struct rtc_wkalrm *alarm)
256{
257	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
258
259	timer->rtc_alarm = rtc_tm_to_time64(&alarm->time);
260
261	brcmstb_waketmr_set_alarm(timer, timer->rtc_alarm);
262
263	return brcmstb_waketmr_alarm_enable(dev, alarm->enabled);
264}
265
266static const struct rtc_class_ops brcmstb_waketmr_ops = {
267	.read_time	= brcmstb_waketmr_gettime,
268	.set_time	= brcmstb_waketmr_settime,
269	.read_alarm	= brcmstb_waketmr_getalarm,
270	.set_alarm	= brcmstb_waketmr_setalarm,
271	.alarm_irq_enable = brcmstb_waketmr_alarm_enable,
272};
273
274static int brcmstb_waketmr_probe(struct platform_device *pdev)
275{
276	struct device *dev = &pdev->dev;
277	struct brcmstb_waketmr *timer;
278	int ret;
279
280	timer = devm_kzalloc(dev, sizeof(*timer), GFP_KERNEL);
281	if (!timer)
282		return -ENOMEM;
283
284	platform_set_drvdata(pdev, timer);
285	timer->dev = dev;
286
287	timer->base = devm_platform_ioremap_resource(pdev, 0);
288	if (IS_ERR(timer->base))
289		return PTR_ERR(timer->base);
290
291	timer->rtc = devm_rtc_allocate_device(dev);
292	if (IS_ERR(timer->rtc))
293		return PTR_ERR(timer->rtc);
294
295	/*
296	 * Set wakeup capability before requesting wakeup interrupt, so we can
297	 * process boot-time "wakeups" (e.g., from S5 soft-off)
298	 */
299	device_init_wakeup(dev, true);
300
301	ret = platform_get_irq(pdev, 0);
302	if (ret < 0)
303		return -ENODEV;
304	timer->wake_irq = (unsigned int)ret;
305
306	timer->clk = devm_clk_get(dev, NULL);
307	if (!IS_ERR(timer->clk)) {
308		ret = clk_prepare_enable(timer->clk);
309		if (ret)
310			return ret;
311		timer->rate = clk_get_rate(timer->clk);
312		if (!timer->rate)
313			timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ;
314	} else {
315		timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ;
316		timer->clk = NULL;
317	}
318
319	ret = devm_request_irq(dev, timer->wake_irq, brcmstb_waketmr_irq, 0,
320			       "brcmstb-waketimer", timer);
321	if (ret < 0)
322		goto err_clk;
323
324	brcmstb_waketmr_clear_alarm(timer);
325
326	/* Attempt to initialize non-wake irq */
327	ret = platform_get_irq(pdev, 1);
328	if (ret > 0) {
329		timer->alarm_irq = (unsigned int)ret;
330		ret = devm_request_irq(dev, timer->alarm_irq, brcmstb_alarm_irq,
331				       IRQF_NO_AUTOEN, "brcmstb-waketimer-rtc",
332				       timer);
333		if (ret < 0)
334			timer->alarm_irq = 0;
335	}
336
337	timer->reboot_notifier.notifier_call = brcmstb_waketmr_reboot;
338	register_reboot_notifier(&timer->reboot_notifier);
339
340	timer->rtc->ops = &brcmstb_waketmr_ops;
341	timer->rtc->range_max = U32_MAX;
342
343	ret = devm_rtc_register_device(timer->rtc);
344	if (ret)
345		goto err_notifier;
346
347	return 0;
348
349err_notifier:
350	unregister_reboot_notifier(&timer->reboot_notifier);
351
352err_clk:
353	clk_disable_unprepare(timer->clk);
354
355	return ret;
356}
357
358static void brcmstb_waketmr_remove(struct platform_device *pdev)
359{
360	struct brcmstb_waketmr *timer = dev_get_drvdata(&pdev->dev);
361
362	unregister_reboot_notifier(&timer->reboot_notifier);
363	clk_disable_unprepare(timer->clk);
364}
365
366#ifdef CONFIG_PM_SLEEP
367static int brcmstb_waketmr_suspend(struct device *dev)
368{
369	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
370
371	return brcmstb_waketmr_prepare_suspend(timer);
372}
373
374static int brcmstb_waketmr_suspend_noirq(struct device *dev)
375{
376	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
377
378	/* Catch any alarms occurring prior to noirq */
379	if (timer->alarm_expired && device_may_wakeup(dev))
380		return -EBUSY;
381
382	return 0;
383}
384
385static int brcmstb_waketmr_resume(struct device *dev)
386{
387	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
388	int ret;
389
390	if (!device_may_wakeup(dev))
391		return 0;
392
393	ret = disable_irq_wake(timer->wake_irq);
394	if (timer->alarm_en && timer->alarm_irq)
395		disable_irq_wake(timer->alarm_irq);
396
397	brcmstb_waketmr_clear_alarm(timer);
398
399	return ret;
400}
401#else
402#define brcmstb_waketmr_suspend		NULL
403#define brcmstb_waketmr_suspend_noirq	NULL
404#define brcmstb_waketmr_resume		NULL
405#endif /* CONFIG_PM_SLEEP */
406
407static const struct dev_pm_ops brcmstb_waketmr_pm_ops = {
408	.suspend	= brcmstb_waketmr_suspend,
409	.suspend_noirq	= brcmstb_waketmr_suspend_noirq,
410	.resume		= brcmstb_waketmr_resume,
411};
412
413static const __maybe_unused struct of_device_id brcmstb_waketmr_of_match[] = {
414	{ .compatible = "brcm,brcmstb-waketimer" },
415	{ /* sentinel */ },
416};
417
418static struct platform_driver brcmstb_waketmr_driver = {
419	.probe			= brcmstb_waketmr_probe,
420	.remove_new		= brcmstb_waketmr_remove,
421	.driver = {
422		.name		= "brcmstb-waketimer",
423		.pm		= &brcmstb_waketmr_pm_ops,
424		.of_match_table	= of_match_ptr(brcmstb_waketmr_of_match),
425	}
426};
427module_platform_driver(brcmstb_waketmr_driver);
428
429MODULE_LICENSE("GPL v2");
430MODULE_AUTHOR("Brian Norris");
431MODULE_AUTHOR("Markus Mayer");
432MODULE_AUTHOR("Doug Berger");
433MODULE_DESCRIPTION("Wake-up timer driver for STB chips");
434