linux-kernel - [PATCH] watchdog: qcom: add support for the bark interrupt

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Date:   Thu,  5 Sep 2019 18:21:35 +0200
From:   Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@...aro.org>
To:     jorge.ramirez-ortiz@...aro.org, agross@...nel.org,
        wim@...ux-watchdog.org
Cc:     linux-arm-msm@...r.kernel.org, linux-watchdog@...r.kernel.org,
        linux-kernel@...r.kernel.org, bjorn.andersson@...aro.org
Subject: [PATCH] watchdog: qcom: add support for the bark interrupt

Use the bark interrupt to notify the bark event. Since the bark and bite
timeouts are identical, increase the bite timeout by one second so
that the bark event can be logged to the console.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@...aro.org>
---
 drivers/watchdog/qcom-wdt.c | 42 ++++++++++++++++++++++++++++++++++---
 1 file changed, 39 insertions(+), 3 deletions(-)

diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
index 7be7f87be28f..5eaf92084b93 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,
@@ -41,6 +42,8 @@ struct qcom_wdt {
 	unsigned long		rate;
 	void __iomem		*base;
 	const u32		*layout;
+	unsigned int		irq;
+	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)
+{
+	if (wdt->irq < 0)
+		return 1;
+
+	/* enable timeout with interrupt */
+	return 3;
+}
+
+static irqreturn_t qcom_wdt_irq(int irq, void *cookie)
+{
+	struct qcom_wdt *wdt =  (struct qcom_wdt *) cookie;
+
+	dev_warn(wdt->dev, "barking, one second countdown to reset\n");
+
+	return IRQ_HANDLED;
+}
+
 static int qcom_wdt_start(struct watchdog_device *wdd)
 {
 	struct qcom_wdt *wdt = to_qcom_wdt(wdd);
+	unsigned int bark, bite;
+
+	bark = wdd->timeout;
+	bite = wdt->irq < 0 ? bark : bark + 1;
 
 	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(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BITE_TIME));
-	writel(1, wdt_addr(wdt, WDT_EN));
+	writel(bark * wdt->rate, wdt_addr(wdt, WDT_BARK_TIME));
+	writel(bite * wdt->rate, wdt_addr(wdt, WDT_BITE_TIME));
+	writel(qcom_wdt_enable(wdt), wdt_addr(wdt, WDT_EN));
 	return 0;
 }
 
@@ -210,10 +235,21 @@ 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;
 
+	wdt->irq = platform_get_irq(pdev, 0);
+	if (wdt->irq >= 0) {
+		ret = devm_request_irq(&pdev->dev, wdt->irq, qcom_wdt_irq,
+				       IRQF_TRIGGER_RISING, "wdog_bark", wdt);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to request irq\n");
+			return ret;
+		}
+	}
+
 	/*
 	 * If 'timeout-sec' unspecified in devicetree, assume a 30 second
 	 * default, unless the max timeout is less than 30 seconds, then use
-- 
2.23.0