// 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");
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