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Subject[PATCH v4] watchdog: qcom: support pre-timeout when the bark irq is available
Date
Use the bark interrupt as the pre-timeout notifier whenever this
interrupt is available.

By default, the pretimeout notification shall occur one second earlier
than the timeout.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
---
v4:
address Guenter Roeck comments as follows:
remove unnecessary include and private variable
provide macro for WDT EN register values
use pretimeout as per its API intent
handle EPROBE_DEFER on get_irq
also:
handle the irq registration as done in pm8916_wdt.c
v3:
remove unnecesary variable added to private.

v2:
register the pre-timeout notifier instead.

v1:
drivers/watchdog/qcom-wdt.c | 64 ++++++++++++++++++++++++++++++++++---
1 file changed, 59 insertions(+), 5 deletions(-)

diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
index 7be7f87be28f..0f1d29eeb81d 100644
--- a/drivers/watchdog/qcom-wdt.c
+++ b/drivers/watchdog/qcom-wdt.c
@@ -10,6 +10,7 @@
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/of_device.h>
+#include <linux/interrupt.h>

enum wdt_reg {
WDT_RST,
@@ -19,6 +20,9 @@ enum wdt_reg {
WDT_BITE_TIME,
};

+#define QCOM_WDT_ENABLE BIT(0)
+#define QCOM_WDT_ENABLE_IRQ BIT(1)
+
static const u32 reg_offset_data_apcs_tmr[] = {
[WDT_RST] = 0x38,
[WDT_EN] = 0x40,
@@ -54,15 +58,38 @@ struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd)
return container_of(wdd, struct qcom_wdt, wdd);
}

+static inline int qcom_get_enable(struct watchdog_device *wdd)
+{
+ int enable = QCOM_WDT_ENABLE;
+
+ if (wdd->info->options & WDIOF_PRETIMEOUT)
+ enable |= QCOM_WDT_ENABLE_IRQ;
+
+ return enable;
+}
+
+static irqreturn_t qcom_wdt_isr(int irq, void *arg)
+{
+ struct watchdog_device *wdd = arg;
+
+ watchdog_notify_pretimeout(wdd);
+
+ return IRQ_HANDLED;
+}
+
static int qcom_wdt_start(struct watchdog_device *wdd)
{
struct qcom_wdt *wdt = to_qcom_wdt(wdd);
+ unsigned int bark = wdd->timeout;
+
+ if (wdd->pretimeout)
+ bark = bark - wdd->pretimeout;

writel(0, wdt_addr(wdt, WDT_EN));
writel(1, wdt_addr(wdt, WDT_RST));
- writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BARK_TIME));
+ writel(bark * wdt->rate, wdt_addr(wdt, WDT_BARK_TIME));
writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BITE_TIME));
- writel(1, wdt_addr(wdt, WDT_EN));
+ writel(qcom_get_enable(wdd), wdt_addr(wdt, WDT_EN));
return 0;
}

@@ -89,6 +116,13 @@ static int qcom_wdt_set_timeout(struct watchdog_device *wdd,
return qcom_wdt_start(wdd);
}

+static int qcom_wdt_set_pretimeout(struct watchdog_device *wdd,
+ unsigned int timeout)
+{
+ wdd->pretimeout = timeout;
+ return qcom_wdt_start(wdd);
+}
+
static int qcom_wdt_restart(struct watchdog_device *wdd, unsigned long action,
void *data)
{
@@ -105,7 +139,7 @@ static int qcom_wdt_restart(struct watchdog_device *wdd, unsigned long action,
writel(1, wdt_addr(wdt, WDT_RST));
writel(timeout, wdt_addr(wdt, WDT_BARK_TIME));
writel(timeout, wdt_addr(wdt, WDT_BITE_TIME));
- writel(1, wdt_addr(wdt, WDT_EN));
+ writel(qcom_get_enable(wdd), wdt_addr(wdt, WDT_EN));

/*
* Actually make sure the above sequence hits hardware before sleeping.
@@ -121,6 +155,7 @@ static const struct watchdog_ops qcom_wdt_ops = {
.stop = qcom_wdt_stop,
.ping = qcom_wdt_ping,
.set_timeout = qcom_wdt_set_timeout,
+ .set_pretimeout = qcom_wdt_set_pretimeout,
.restart = qcom_wdt_restart,
.owner = THIS_MODULE,
};
@@ -133,6 +168,15 @@ static const struct watchdog_info qcom_wdt_info = {
.identity = KBUILD_MODNAME,
};

+static const struct watchdog_info qcom_wdt_pt_info = {
+ .options = WDIOF_KEEPALIVEPING
+ | WDIOF_MAGICCLOSE
+ | WDIOF_SETTIMEOUT
+ | WDIOF_PRETIMEOUT
+ | WDIOF_CARDRESET,
+ .identity = KBUILD_MODNAME,
+};
+
static void qcom_clk_disable_unprepare(void *data)
{
clk_disable_unprepare(data);
@@ -146,7 +190,7 @@ static int qcom_wdt_probe(struct platform_device *pdev)
struct device_node *np = dev->of_node;
const u32 *regs;
u32 percpu_offset;
- int ret;
+ int irq, ret;

regs = of_device_get_match_data(dev);
if (!regs) {
@@ -204,7 +248,17 @@ static int qcom_wdt_probe(struct platform_device *pdev)
return -EINVAL;
}

- wdt->wdd.info = &qcom_wdt_info;
+ irq = platform_get_irq(pdev, 0);
+ if (irq > 0) {
+ if (devm_request_irq(dev, irq, qcom_wdt_isr,
+ IRQF_TRIGGER_RISING, "wdt_bark",
+ &wdt->wdd))
+ irq = 0;
+ } else if (irq == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+
+ wdt->wdd.info = irq > 0 ? &qcom_wdt_pt_info : &qcom_wdt_info;
+ wdt->wdd.pretimeout = irq > 0 ? 1 : 0;
wdt->wdd.ops = &qcom_wdt_ops;
wdt->wdd.min_timeout = 1;
wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
--
2.23.0
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