From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Lezcano <daniel.lezcano-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH 1/7] clocksource: mediatek: Don't run event_handler if
 it is NULL
Date: Mon, 04 May 2015 10:44:18 +0200
Message-ID: <55473162.5010608@linaro.org>
References: <1430466210-22963-1-git-send-email-yingjoe.chen@mediatek.com>	<1430466210-22963-2-git-send-email-yingjoe.chen@mediatek.com>	<55472A80.9020904@linaro.org> <CABuKBeKBcg+zCDSx8PNCsRC3A8Lo9ripw5ZYCC0c+GjJN8dp6Q@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8;
	format=flowed
Content-Transfer-Encoding: QUOTED-PRINTABLE
Return-path: <devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
In-Reply-To: <CABuKBeKBcg+zCDSx8PNCsRC3A8Lo9ripw5ZYCC0c+GjJN8dp6Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
To: Matthias Brugger <matthias.bgg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Yingjoe Chen <yingjoe.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>, Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>, Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>, Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>, Olof Johansson <olof-nZhT3qVonbNeoWH0uzbU5w@public.gmane.org>, Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org>, Ian Campbell <ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org>, Russell King <linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>, Jason Cooper <jason-NLaQJdtUoK4Be96aLqz0jA@public.gmane.org>, Catalin Marinas <catalin.marinas-5wv7dgnIgG8@public.gmane.org>, Marc Carino <marc.ceeeee-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Lorenzo Pieralisi <lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>, "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" <linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>, linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, srv_heupstream <srv_heupstream-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>, Sascha Hauer <kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
List-Id: devicetree@vger.kernel.org

On 05/04/2015 10:34 AM, Matthias Brugger wrote:
> 2015-05-04 10:14 GMT+02:00 Daniel Lezcano <daniel.lezcano-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>=
:
>> On 05/01/2015 09:43 AM, Yingjoe Chen wrote:
>>>
>>> Spurious timer interrupt is noticed in mtk timer and cause kernel
>>> crash. In mtk_timer_interrupt(), only run event_handler if it is
>>> not NULL.
>>>
>>> Signed-off-by: Yingjoe Chen <yingjoe.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
>>> ---
>>>    drivers/clocksource/mtk_timer.c | 3 ++-
>>>    1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/clocksource/mtk_timer.c
>>> b/drivers/clocksource/mtk_timer.c
>>> index 68ab423..85e0ab5 100644
>>> --- a/drivers/clocksource/mtk_timer.c
>>> +++ b/drivers/clocksource/mtk_timer.c
>>> @@ -143,7 +143,8 @@ static irqreturn_t mtk_timer_interrupt(int irq,=
 void
>>> *dev_id)
>>>
>>>          /* Acknowledge timer0 irq */
>>>          writel(GPT_IRQ_ACK(GPT_CLK_EVT), evt->gpt_base + GPT_IRQ_A=
CK_REG);
>>> -       evt->dev.event_handler(&evt->dev);
>>> +       if (evt->dev.event_handler)
>>> +               evt->dev.event_handler(&evt->dev);
>>>
>>>          return IRQ_HANDLED;
>>>    }
>>>
>>
>> This fix does not look good.
>>
>> Could you try by requesting the irq *after* clockevents_config_and_r=
egister
>> in the init sequence [1] ?
>>
>
>  From my understanding [1] should already fix this.
>
> [1] https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.=
git/commit/drivers/clocksource/mtk_timer.c?id=3Dd4a19eb3b15a4ba98f62718=
2f48d5bc0cffae670

Indeed it seems to fix it. But I think request_irq should be done after=
=20
clockevents_config_and_register in any case.

Yingjoe, are the spurious interrupts occurring with the fix Matthias=20
mentions ?


--=20
  <http://www.linaro.org/> Linaro.org =E2=94=82 Open source software fo=
r ARM SoCs

=46ollow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog

--
To unsubscribe from this list: send the line "unsubscribe devicetree" i=
n
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html