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

Signed-off-by: Robin Gong <b38...@freescale.com>
---
 drivers/watchdog/imx2_wdt.c | 67 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 66 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
index 0bb1a1d..d3c6b07 100644
--- a/drivers/watchdog/imx2_wdt.c
+++ b/drivers/watchdog/imx2_wdt.c
@@ -24,7 +24,9 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/init.h>
+#include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/irq.h>
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -52,12 +54,18 @@
 #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 << 0)     /* 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 +88,8 @@ 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 +216,59 @@ static inline void imx2_wdt_ping_if_active(struct 
watchdog_device *wdog)
        }
 }
 
+static int imx2_wdt_check_pretimeout_set(struct imx2_wdt_device *wdev)
+{
+       u32 val;
+
+       regmap_read(wdev->regmap, IMX2_WDT_WICR, &val);
+       return (val & IMX2_WDT_WICR_WIE) ? 1 : 0;
+}
+
+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);
+
+       if (!imx2_wdt_check_pretimeout_set(wdev))
+               val |= IMX2_WDT_WICR_WIE;       /*enable*/
+
+       regmap_write(wdev->regmap, IMX2_WDT_WICR, val);
+
+       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);
+               dev_warn(&pdev->dev, "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 +285,7 @@ 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);
@@ -253,6 +310,14 @@ static int __init imx2_wdt_probe(struct platform_device 
*pdev)
                return PTR_ERR(wdev->clk);
        }
 
+       irq = platform_get_irq(pdev, 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);
+               return ret;
+       }
+
        wdog                    = &wdev->wdog;
        wdog->info              = &imx2_wdt_info;
        wdog->ops               = &imx2_wdt_ops;
-- 
1.9.1

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