1 files changed, 433 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-brcmstb-waketimer.c b/drivers/rtc/rtc-brcmstb-waketimer.c
new file mode 100644
index 000000000..1a65a4e0d
--- /dev/null
+++ b/drivers/rtc/rtc-brcmstb-waketimer.c
@@ -0,0 +1,433 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright © 2014-2023 Broadcom
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irqreturn.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/pm_wakeup.h>
+#include <linux/reboot.h>
+#include <linux/rtc.h>
+#include <linux/stat.h>
+#include <linux/suspend.h>
+
+struct brcmstb_waketmr {
+	struct rtc_device *rtc;
+	struct device *dev;
+	void __iomem *base;
+	unsigned int wake_irq;
+	unsigned int alarm_irq;
+	struct notifier_block reboot_notifier;
+	struct clk *clk;
+	u32 rate;
+	unsigned long rtc_alarm;
+	bool alarm_en;
+	bool alarm_expired;
+};
+
+#define BRCMSTB_WKTMR_EVENT		0x00
+#define  WKTMR_ALARM_EVENT		BIT(0)
+#define BRCMSTB_WKTMR_COUNTER		0x04
+#define BRCMSTB_WKTMR_ALARM		0x08
+#define BRCMSTB_WKTMR_PRESCALER		0x0C
+#define BRCMSTB_WKTMR_PRESCALER_VAL	0x10
+
+#define BRCMSTB_WKTMR_DEFAULT_FREQ	27000000
+
+static inline bool brcmstb_waketmr_is_pending(struct brcmstb_waketmr *timer)
+{
+	u32 reg;
+
+	reg = readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
+	return !!(reg & WKTMR_ALARM_EVENT);
+}
+
+static inline void brcmstb_waketmr_clear_alarm(struct brcmstb_waketmr *timer)
+{
+	u32 reg;
+
+	if (timer->alarm_en && timer->alarm_irq)
+		disable_irq(timer->alarm_irq);
+	timer->alarm_en = false;
+	reg = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
+	writel_relaxed(reg - 1, timer->base + BRCMSTB_WKTMR_ALARM);
+	writel_relaxed(WKTMR_ALARM_EVENT, timer->base + BRCMSTB_WKTMR_EVENT);
+	(void)readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
+	if (timer->alarm_expired) {
+		timer->alarm_expired = false;
+		/* maintain call balance */
+		enable_irq(timer->alarm_irq);
+	}
+}
+
+static void brcmstb_waketmr_set_alarm(struct brcmstb_waketmr *timer,
+				      unsigned int secs)
+{
+	unsigned int now;
+
+	brcmstb_waketmr_clear_alarm(timer);
+
+	/* Make sure we are actually counting in seconds */
+	writel_relaxed(timer->rate, timer->base + BRCMSTB_WKTMR_PRESCALER);
+
+	writel_relaxed(secs, timer->base + BRCMSTB_WKTMR_ALARM);
+	now = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
+
+	while ((int)(secs - now) <= 0 &&
+		!brcmstb_waketmr_is_pending(timer)) {
+		secs = now + 1;
+		writel_relaxed(secs, timer->base + BRCMSTB_WKTMR_ALARM);
+		now = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
+	}
+}
+
+static irqreturn_t brcmstb_waketmr_irq(int irq, void *data)
+{
+	struct brcmstb_waketmr *timer = data;
+
+	if (!timer->alarm_irq)
+		pm_wakeup_event(timer->dev, 0);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t brcmstb_alarm_irq(int irq, void *data)
+{
+	struct brcmstb_waketmr *timer = data;
+
+	/* Ignore spurious interrupts */
+	if (!brcmstb_waketmr_is_pending(timer))
+		return IRQ_HANDLED;
+
+	if (timer->alarm_en) {
+		if (device_may_wakeup(timer->dev)) {
+			disable_irq_nosync(irq);
+			timer->alarm_expired = true;
+		} else {
+			writel_relaxed(WKTMR_ALARM_EVENT,
+				       timer->base + BRCMSTB_WKTMR_EVENT);
+		}
+		rtc_update_irq(timer->rtc, 1, RTC_IRQF | RTC_AF);
+	} else {
+		writel_relaxed(WKTMR_ALARM_EVENT,
+			       timer->base + BRCMSTB_WKTMR_EVENT);
+	}
+
+	return IRQ_HANDLED;
+}
+
+struct wktmr_time {
+	u32 sec;
+	u32 pre;
+};
+
+static void wktmr_read(struct brcmstb_waketmr *timer,
+		       struct wktmr_time *t)
+{
+	u32 tmp;
+
+	do {
+		t->sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
+		tmp = readl_relaxed(timer->base + BRCMSTB_WKTMR_PRESCALER_VAL);
+	} while (tmp >= timer->rate);
+
+	t->pre = timer->rate - tmp;
+}
+
+static int brcmstb_waketmr_prepare_suspend(struct brcmstb_waketmr *timer)
+{
+	struct device *dev = timer->dev;
+	int ret;
+
+	if (device_may_wakeup(dev)) {
+		ret = enable_irq_wake(timer->wake_irq);
+		if (ret) {
+			dev_err(dev, "failed to enable wake-up interrupt\n");
+			return ret;
+		}
+		if (timer->alarm_en && timer->alarm_irq) {
+			ret = enable_irq_wake(timer->alarm_irq);
+			if (ret) {
+				dev_err(dev, "failed to enable rtc interrupt\n");
+				disable_irq_wake(timer->wake_irq);
+				return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/* If enabled as a wakeup-source, arm the timer when powering off */
+static int brcmstb_waketmr_reboot(struct notifier_block *nb,
+		unsigned long action, void *data)
+{
+	struct brcmstb_waketmr *timer;
+
+	timer = container_of(nb, struct brcmstb_waketmr, reboot_notifier);
+
+	/* Set timer for cold boot */
+	if (action == SYS_POWER_OFF)
+		brcmstb_waketmr_prepare_suspend(timer);
+
+	return NOTIFY_DONE;
+}
+
+static int brcmstb_waketmr_gettime(struct device *dev,
+				   struct rtc_time *tm)
+{
+	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
+	struct wktmr_time now;
+
+	wktmr_read(timer, &now);
+
+	rtc_time64_to_tm(now.sec, tm);
+
+	return 0;
+}
+
+static int brcmstb_waketmr_settime(struct device *dev,
+				   struct rtc_time *tm)
+{
+	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
+	time64_t sec;
+
+	sec = rtc_tm_to_time64(tm);
+
+	writel_relaxed(sec, timer->base + BRCMSTB_WKTMR_COUNTER);
+
+	return 0;
+}
+
+static int brcmstb_waketmr_getalarm(struct device *dev,
+				    struct rtc_wkalrm *alarm)
+{
+	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
+
+	alarm->enabled = timer->alarm_en;
+	rtc_time64_to_tm(timer->rtc_alarm, &alarm->time);
+
+	alarm->pending = brcmstb_waketmr_is_pending(timer);
+
+	return 0;
+}
+
+static int brcmstb_waketmr_alarm_enable(struct device *dev,
+					unsigned int enabled)
+{
+	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
+
+	if (enabled && !timer->alarm_en) {
+		if ((int)(readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER) -
+		    readl_relaxed(timer->base + BRCMSTB_WKTMR_ALARM)) >= 0 &&
+		    !brcmstb_waketmr_is_pending(timer))
+			return -EINVAL;
+		timer->alarm_en = true;
+		if (timer->alarm_irq) {
+			if (timer->alarm_expired) {
+				timer->alarm_expired = false;
+				/* maintain call balance */
+				enable_irq(timer->alarm_irq);
+			}
+			enable_irq(timer->alarm_irq);
+		}
+	} else if (!enabled && timer->alarm_en) {
+		if (timer->alarm_irq)
+			disable_irq(timer->alarm_irq);
+		timer->alarm_en = false;
+	}
+
+	return 0;
+}
+
+static int brcmstb_waketmr_setalarm(struct device *dev,
+				     struct rtc_wkalrm *alarm)
+{
+	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
+
+	timer->rtc_alarm = rtc_tm_to_time64(&alarm->time);
+
+	brcmstb_waketmr_set_alarm(timer, timer->rtc_alarm);
+
+	return brcmstb_waketmr_alarm_enable(dev, alarm->enabled);
+}
+
+static const struct rtc_class_ops brcmstb_waketmr_ops = {
+	.read_time	= brcmstb_waketmr_gettime,
+	.set_time	= brcmstb_waketmr_settime,
+	.read_alarm	= brcmstb_waketmr_getalarm,
+	.set_alarm	= brcmstb_waketmr_setalarm,
+	.alarm_irq_enable = brcmstb_waketmr_alarm_enable,
+};
+
+static int brcmstb_waketmr_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct brcmstb_waketmr *timer;
+	int ret;
+
+	timer = devm_kzalloc(dev, sizeof(*timer), GFP_KERNEL);
+	if (!timer)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, timer);
+	timer->dev = dev;
+
+	timer->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(timer->base))
+		return PTR_ERR(timer->base);
+
+	timer->rtc = devm_rtc_allocate_device(dev);
+	if (IS_ERR(timer->rtc))
+		return PTR_ERR(timer->rtc);
+
+	/*
+	 * Set wakeup capability before requesting wakeup interrupt, so we can
+	 * process boot-time "wakeups" (e.g., from S5 soft-off)
+	 */
+	device_init_wakeup(dev, true);
+
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0)
+		return -ENODEV;
+	timer->wake_irq = (unsigned int)ret;
+
+	timer->clk = devm_clk_get(dev, NULL);
+	if (!IS_ERR(timer->clk)) {
+		ret = clk_prepare_enable(timer->clk);
+		if (ret)
+			return ret;
+		timer->rate = clk_get_rate(timer->clk);
+		if (!timer->rate)
+			timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ;
+	} else {
+		timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ;
+		timer->clk = NULL;
+	}
+
+	ret = devm_request_irq(dev, timer->wake_irq, brcmstb_waketmr_irq, 0,
+			       "brcmstb-waketimer", timer);
+	if (ret < 0)
+		goto err_clk;
+
+	brcmstb_waketmr_clear_alarm(timer);
+
+	/* Attempt to initialize non-wake irq */
+	ret = platform_get_irq(pdev, 1);
+	if (ret > 0) {
+		timer->alarm_irq = (unsigned int)ret;
+		ret = devm_request_irq(dev, timer->alarm_irq, brcmstb_alarm_irq,
+				       IRQF_NO_AUTOEN, "brcmstb-waketimer-rtc",
+				       timer);
+		if (ret < 0)
+			timer->alarm_irq = 0;
+	}
+
+	timer->reboot_notifier.notifier_call = brcmstb_waketmr_reboot;
+	register_reboot_notifier(&timer->reboot_notifier);
+
+	timer->rtc->ops = &brcmstb_waketmr_ops;
+	timer->rtc->range_max = U32_MAX;
+
+	ret = devm_rtc_register_device(timer->rtc);
+	if (ret)
+		goto err_notifier;
+
+	return 0;
+
+err_notifier:
+	unregister_reboot_notifier(&timer->reboot_notifier);
+
+err_clk:
+	clk_disable_unprepare(timer->clk);
+
+	return ret;
+}
+
+static void brcmstb_waketmr_remove(struct platform_device *pdev)
+{
+	struct brcmstb_waketmr *timer = dev_get_drvdata(&pdev->dev);
+
+	unregister_reboot_notifier(&timer->reboot_notifier);
+	clk_disable_unprepare(timer->clk);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int brcmstb_waketmr_suspend(struct device *dev)
+{
+	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
+
+	return brcmstb_waketmr_prepare_suspend(timer);
+}
+
+static int brcmstb_waketmr_suspend_noirq(struct device *dev)
+{
+	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
+
+	/* Catch any alarms occurring prior to noirq */
+	if (timer->alarm_expired && device_may_wakeup(dev))
+		return -EBUSY;
+
+	return 0;
+}
+
+static int brcmstb_waketmr_resume(struct device *dev)
+{
+	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
+	int ret;
+
+	if (!device_may_wakeup(dev))
+		return 0;
+
+	ret = disable_irq_wake(timer->wake_irq);
+	if (timer->alarm_en && timer->alarm_irq)
+		disable_irq_wake(timer->alarm_irq);
+
+	brcmstb_waketmr_clear_alarm(timer);
+
+	return ret;
+}
+#else
+#define brcmstb_waketmr_suspend		NULL
+#define brcmstb_waketmr_suspend_noirq	NULL
+#define brcmstb_waketmr_resume		NULL
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops brcmstb_waketmr_pm_ops = {
+	.suspend	= brcmstb_waketmr_suspend,
+	.suspend_noirq	= brcmstb_waketmr_suspend_noirq,
+	.resume		= brcmstb_waketmr_resume,
+};
+
+static const __maybe_unused struct of_device_id brcmstb_waketmr_of_match[] = {
+	{ .compatible = "brcm,brcmstb-waketimer" },
+	{ /* sentinel */ },
+};
+
+static struct platform_driver brcmstb_waketmr_driver = {
+	.probe			= brcmstb_waketmr_probe,
+	.remove_new		= brcmstb_waketmr_remove,
+	.driver = {
+		.name		= "brcmstb-waketimer",
+		.pm		= &brcmstb_waketmr_pm_ops,
+		.of_match_table	= of_match_ptr(brcmstb_waketmr_of_match),
+	}
+};
+module_platform_driver(brcmstb_waketmr_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Brian Norris");
+MODULE_AUTHOR("Markus Mayer");
+MODULE_AUTHOR("Doug Berger");
+MODULE_DESCRIPTION("Wake-up timer driver for STB chips");