On 10/31/20 5:11 AM, Robert Marko wrote:
> If the watchdog hardware is enabled/running during boot, e.g.
> due to a boot loader configuring it, we must tell the
> watchdog framework about this fact so that it can ping the
> watchdog until userspace opens the device and takes over
> control.
>
> Do so using the WDOG_HW_RUNNING flag that exists for exactly
> that use-case.
>
> Signed-off-by: Robert Marko <robert.marko@xxxxxxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> Cc: Luka Perkov <luka.perkov@xxxxxxxxxx>
> ---
> Changes in v4:
> * Use QCOM_WDT_ENABLE macro
>
> Changes in v3:
> * Drop call to stop as start already does it
> * Update commit message
>
> Changes in v2:
> * Correct authorship
>
> drivers/watchdog/qcom-wdt.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
> index ab7465d186fd..07d399c4edc4 100644
> --- a/drivers/watchdog/qcom-wdt.c
> +++ b/drivers/watchdog/qcom-wdt.c
> @@ -152,6 +152,13 @@ static int qcom_wdt_restart(struct watchdog_device *wdd, unsigned long action,
> return 0;
> }
>
> +static int qcom_wdt_is_running(struct watchdog_device *wdd)
> +{
> + struct qcom_wdt *wdt = to_qcom_wdt(wdd);
> +
> + return (readl(wdt_addr(wdt, WDT_EN)) & QCOM_WDT_ENABLE);
> +}
> +
> static const struct watchdog_ops qcom_wdt_ops = {
> .start = qcom_wdt_start,
> .stop = qcom_wdt_stop,
> @@ -294,6 +301,17 @@ 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);
>
> + /*
> + * If WDT is already running, call WDT start which
> + * will stop the WDT, set timeouts as bootloader
> + * might use different ones and set running bit
> + * to inform the WDT subsystem to ping the WDT
> + */
> + if (qcom_wdt_is_running(&wdt->wdd)) {
> + qcom_wdt_start(&wdt->wdd);
> + set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
> + }
> +
> ret = devm_watchdog_register_device(dev, &wdt->wdd);
> if (ret)
> return ret;
>
