From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Robert Marko <robert.marko@sartura.hr>
Cc: agross@kernel.org, wim@linux-watchdog.org, linux@roeck-us.net,
linux-arm-msm@vger.kernel.org, linux-watchdog@vger.kernel.org,
linux-kernel@vger.kernel.org,
Luka Perkov <luka.perkov@sartura.hr>
Subject: Re: [PATCH v4] watchdog: qcom_wdt: set WDOG_HW_RUNNING bit when appropriate
Date: Mon, 30 Nov 2020 17:23:15 -0600 [thread overview]
Message-ID: <X8V+442lvcTpNmth@builder.lan> (raw)
In-Reply-To: <20201031121115.542752-1-robert.marko@sartura.hr>
On Sat 31 Oct 07:11 CDT 2020, 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@sartura.hr>
> Cc: Luka Perkov <luka.perkov@sartura.hr>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
> 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);
Although, you don't need the outer () here.
Regards,
Bjorn
> +}
> +
> 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;
> --
> 2.28.0
>
prev parent reply other threads:[~2020-11-30 23:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-31 12:11 [PATCH v4] watchdog: qcom_wdt: set WDOG_HW_RUNNING bit when appropriate Robert Marko
2020-10-31 14:08 ` Guenter Roeck
2020-11-02 3:58 ` Kathiravan T
2020-11-02 5:03 ` Guenter Roeck
2020-11-02 5:19 ` Kathiravan T
2020-11-30 18:27 ` Robert Marko
2020-11-30 23:56 ` Guenter Roeck
2020-11-30 23:23 ` Bjorn Andersson [this message]
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