From: Kathiravan T <kathirav@codeaurora.org>
To: Guenter Roeck <linux@roeck-us.net>,
Robert Marko <robert.marko@sartura.hr>,
agross@kernel.org, bjorn.andersson@linaro.org,
wim@linux-watchdog.org, linux-arm-msm@vger.kernel.org,
linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Luka Perkov <luka.perkov@sartura.hr>
Subject: Re: [PATCH v4] watchdog: qcom_wdt: set WDOG_HW_RUNNING bit when appropriate
Date: Mon, 2 Nov 2020 09:28:41 +0530 [thread overview]
Message-ID: <23aea80f-265b-8a23-e8ea-f46639dd4129@codeaurora.org> (raw)
In-Reply-To: <a71307f5-22b4-0d38-2880-96084bb07275@roeck-us.net>
On 10/31/2020 7:38 PM, Guenter Roeck wrote:
> 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@sartura.hr>
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Thanks for addressing the comments and now the patch looks good to me.
One more suggestion, can we make the initcall level of the driver to
subsys_initcall_sync so that the driver gets registered immediately
after the watchdog_core is registered and watchdog_core starts pinging
the WDT?
>> Cc: Luka Perkov <luka.perkov@sartura.hr>
>> ---
>> 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;
>>
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
next prev parent reply other threads:[~2020-11-02 3:58 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 [this message]
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
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