[PATCH v3] watchdog: intel-mid_wdt: Keep watchdog running

[PATCH v3] watchdog: intel-mid_wdt: Keep watchdog running

[Andy Shevchenko]

Firmware followed by bootloader leaves watchdog running.

Keep it running in the driver.

User will not need any additional options to reboot in case of panic
during boot.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/watchdog/intel-mid_wdt.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/intel-mid_wdt.c b/drivers/watchdog/intel-mid_wdt.c
index 45e4d02221b5..72c108a12c19 100644
--- a/drivers/watchdog/intel-mid_wdt.c
+++ b/drivers/watchdog/intel-mid_wdt.c
@@ -147,8 +147,21 @@ static int mid_wdt_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	/* Make sure the watchdog is not running */
-	wdt_stop(wdt_dev);
+	/*
+	 * The firmware followed by U-Boot leaves the watchdog running
+	 * with the default threshold which may vary. When we get here
+	 * we should make a decision to prevent any side effects before
+	 * user space daemon will take care of it. The best option,
+	 * taking into consideration that there is no way to read values
+	 * back from hardware, is to enforce watchdog being run with
+	 * deterministic values.
+	 */
+	ret = wdt_start(wdt_dev);
+	if (ret)
+		return ret;
+
+	/* Make sure the watchdog is serviced */
+	set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
 
 	ret = devm_watchdog_register_device(&pdev->dev, wdt_dev);
 	if (ret) {
-- 
2.11.0

Re: [PATCH v3] watchdog: intel-mid_wdt: Keep watchdog running

[Guenter Roeck]

On 03/10/2017 02:22 PM, Andy Shevchenko wrote:
> Firmware followed by bootloader leaves watchdog running.
>
> Keep it running in the driver.
>
> User will not need any additional options to reboot in case of panic
> during boot.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  drivers/watchdog/intel-mid_wdt.c | 17 +++++++++++++++--
>  1 file changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/watchdog/intel-mid_wdt.c b/drivers/watchdog/intel-mid_wdt.c
> index 45e4d02221b5..72c108a12c19 100644
> --- a/drivers/watchdog/intel-mid_wdt.c
> +++ b/drivers/watchdog/intel-mid_wdt.c
> @@ -147,8 +147,21 @@ static int mid_wdt_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>
> -	/* Make sure the watchdog is not running */
> -	wdt_stop(wdt_dev);
> +	/*
> +	 * The firmware followed by U-Boot leaves the watchdog running
> +	 * with the default threshold which may vary. When we get here
> +	 * we should make a decision to prevent any side effects before
> +	 * user space daemon will take care of it. The best option,
> +	 * taking into consideration that there is no way to read values
> +	 * back from hardware, is to enforce watchdog being run with
> +	 * deterministic values.
> +	 */
> +	ret = wdt_start(wdt_dev);
> +	if (ret)
> +		return ret;
> +
> +	/* Make sure the watchdog is serviced */
> +	set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
>
>  	ret = devm_watchdog_register_device(&pdev->dev, wdt_dev);
>  	if (ret) {
>