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-or...@linaro.org>
---
 drivers/watchdog/qcom-wdt.c | 63 ++++++++++++++++++++++++++++++++++---
 1 file changed, 58 insertions(+), 5 deletions(-)

diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
index 7be7f87be28f..2dd36914aa82 100644
--- a/drivers/watchdog/qcom-wdt.c
+++ b/drivers/watchdog/qcom-wdt.c
@@ -10,6 +10,8 @@
 #include <linux/platform_device.h>
 #include <linux/watchdog.h>
 #include <linux/of_device.h>
+#include <linux/interrupt.h>
+#include <linux/watchdog.h>
 
 enum wdt_reg {
        WDT_RST,
@@ -41,6 +43,7 @@ struct qcom_wdt {
        unsigned long           rate;
        void __iomem            *base;
        const u32               *layout;
+       const struct device     *dev;
 };
 
 static void __iomem *wdt_addr(struct qcom_wdt *wdt, enum wdt_reg reg)
@@ -54,15 +57,37 @@ struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd)
        return container_of(wdd, struct qcom_wdt, wdd);
 }
 
+static inline int qcom_wdt_enable(struct qcom_wdt *wdt)
+{
+       /* enable the bark interrupt */
+       if (wdt->wdd.info->options & WDIOF_PRETIMEOUT)
+               return 3;
+
+       return 1;
+}
+
+static irqreturn_t qcom_wdt_irq(int irq, void *cookie)
+{
+       struct watchdog_device *wdd = (struct watchdog_device *) cookie;
+
+       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->pretimeout;
+
+       if (!(wdd->info->options & WDIOF_PRETIMEOUT))
+               bark = wdd->timeout;
 
        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_wdt_enable(wdt), wdt_addr(wdt, WDT_EN));
        return 0;
 }
 
@@ -86,9 +111,18 @@ static int qcom_wdt_set_timeout(struct watchdog_device *wdd,
                                unsigned int timeout)
 {
        wdd->timeout = timeout;
+
        return qcom_wdt_start(wdd);
 }
 
+static int qcom_wdt_set_pretimeout(struct watchdog_device *wdd,
+                                  unsigned int timeout)
+{
+       wdd->pretimeout = timeout;
+
+       return 0;
+}
+
 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_wdt_enable(wdt), wdt_addr(wdt, WDT_EN));
 
        /*
         * Actually make sure the above sequence hits hardware before sleeping.
@@ -121,11 +155,12 @@ 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,
 };
 
-static const struct watchdog_info qcom_wdt_info = {
+static struct watchdog_info qcom_wdt_info = {
        .options        = WDIOF_KEEPALIVEPING
                        | WDIOF_MAGICCLOSE
                        | WDIOF_SETTIMEOUT
@@ -146,7 +181,7 @@ 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) {
@@ -210,6 +245,7 @@ static int qcom_wdt_probe(struct platform_device *pdev)
        wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
        wdt->wdd.parent = dev;
        wdt->layout = regs;
+       wdt->dev = &pdev->dev;
 
        if (readl(wdt_addr(wdt, WDT_STS)) & 1)
                wdt->wdd.bootstatus = WDIOF_CARDRESET;
@@ -222,6 +258,23 @@ static int qcom_wdt_probe(struct platform_device *pdev)
        wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
        watchdog_init_timeout(&wdt->wdd, 0, dev);
 
+       irq = platform_get_irq(pdev, 0);
+       if (irq >= 0) {
+               /* enable the pre-timeout notification */
+               qcom_wdt_info.options |= WDIOF_PRETIMEOUT;
+
+               ret = devm_request_irq(&pdev->dev, irq, qcom_wdt_irq,
+                                      IRQF_TRIGGER_RISING, "wdog_bark",
+                                      &wdt->wdd);
+               if (ret) {
+                       dev_err(&pdev->dev, "failed to request irq\n");
+                       return ret;
+               }
+       }
+
+       if (qcom_wdt_info.options & WDIOF_PRETIMEOUT)
+               wdt->wdd.pretimeout = wdt->wdd.timeout - 1;
+
        ret = devm_watchdog_register_device(dev, &wdt->wdd);
        if (ret)
                return ret;
-- 
2.23.0

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