[PATCH v3 2/2] watchdog: imx2_wdt: add set_pretimeout interface

[Robin Gong]

Enable set_pretimeout interface and trigger the pretimeout interrupt before
watchdog timeout event happen.

Signed-off-by: Robin Gong <b38343@xxxxxxxxxxxxx>
---
 drivers/watchdog/imx2_wdt.c | 58 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 57 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
index 0bb1a1d..06631cf 100644
--- a/drivers/watchdog/imx2_wdt.c
+++ b/drivers/watchdog/imx2_wdt.c
@@ -24,6 +24,7 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/init.h>
+#include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
@@ -52,12 +53,18 @@
 #define IMX2_WDT_WRSR		0x04		/* Reset Status Register */
 #define IMX2_WDT_WRSR_TOUT	(1 << 1)	/* -> Reset due to Timeout */
 
+#define IMX2_WDT_WICR		0x06		/*Interrupt Control Register*/
+#define IMX2_WDT_WICR_WIE	(1 << 15)	/* -> Interrupt Enable */
+#define IMX2_WDT_WICR_WTIS	(1 << 14)	/* -> Interrupt Status */
+#define IMX2_WDT_WICR_WICT	0xFF	/* Watchdog Interrupt Timeout */
+
 #define IMX2_WDT_WMCR		0x08		/* Misc Register */
 
 #define IMX2_WDT_MAX_TIME	128
 #define IMX2_WDT_DEFAULT_TIME	60		/* in seconds */
 
 #define WDOG_SEC_TO_COUNT(s)	((s * 2 - 1) << 8)
+#define WDOG_SEC_TO_PRECOUNT(s)	((s) * 2)	/* set WDOG pre timeout count*/
 
 struct imx2_wdt_device {
 	struct clk *clk;
@@ -80,7 +87,8 @@ MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
 
 static const struct watchdog_info imx2_wdt_info = {
 	.identity = "imx2+ watchdog",
-	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
+	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE
+		   | WDIOF_PRETIMEOUT,
 };
 
 static int imx2_restart_handler(struct notifier_block *this, unsigned long mode,
@@ -207,12 +215,49 @@ static inline void imx2_wdt_ping_if_active(struct watchdog_device *wdog)
 	}
 }
 
+static int imx2_wdt_set_pretimeout(struct watchdog_device *wdog,
+				   unsigned int new_timeout)
+{
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+	u32 val;
+
+	regmap_read(wdev->regmap, IMX2_WDT_WICR, &val);
+	/* set the new pre-timeout value in the WSR */
+	val &= ~IMX2_WDT_WICR_WICT;
+	val |= WDOG_SEC_TO_PRECOUNT(new_timeout);
+
+	regmap_write(wdev->regmap, IMX2_WDT_WICR, val | IMX2_WDT_WICR_WIE);
+
+	wdog->pretimeout = new_timeout;
+
+	return 0;
+}
+
+static irqreturn_t imx2_wdt_isr(int irq, void *dev_id)
+{
+	struct platform_device *pdev = dev_id;
+	struct watchdog_device *wdog = platform_get_drvdata(pdev);
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+	u32 val;
+
+	regmap_read(wdev->regmap, IMX2_WDT_WICR, &val);
+	if (val & IMX2_WDT_WICR_WTIS) {
+		/*clear interrupt status bit*/
+		regmap_write(wdev->regmap, IMX2_WDT_WICR, val);
+		panic("pre-timeout:%d, %d seconds remained\n", wdog->pretimeout,
+		      wdog->timeout - wdog->pretimeout);
+	}
+
+	return IRQ_HANDLED;
+}
+
 static const struct watchdog_ops imx2_wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = imx2_wdt_start,
 	.stop = imx2_wdt_stop,
 	.ping = imx2_wdt_ping,
 	.set_timeout = imx2_wdt_set_timeout,
+	.set_pretimeout = imx2_wdt_set_pretimeout,
 };
 
 static const struct regmap_config imx2_wdt_regmap_config = {
@@ -229,6 +274,7 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
 	struct resource *res;
 	void __iomem *base;
 	int ret;
+	int irq;
 	u32 val;
 
 	wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
@@ -294,6 +340,16 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
 		goto disable_clk;
 	}
 
+	irq = platform_get_irq(pdev, 0);
+	if (irq > 0) {
+		ret = devm_request_irq(&pdev->dev, irq, imx2_wdt_isr, 0,
+				       dev_name(&pdev->dev), pdev);
+		if (ret) {
+			dev_err(&pdev->dev, "can't get irq %d\n", irq);
+			goto disable_clk;
+		}
+	}
+
 	wdev->restart_handler.notifier_call = imx2_restart_handler;
 	wdev->restart_handler.priority = 128;
 	ret = register_restart_handler(&wdev->restart_handler);
-- 
1.9.1

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