From: Guenter Roeck <linux@roeck-us.net>
To: Roger Lu <roger.lu@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>,
Enric Balletbo Serra <eballetbo@gmail.com>,
Kevin Hilman <khilman@kernel.org>,
Rob Herring <robh+dt@kernel.org>,
Nicolas Boichat <drinkcat@google.com>,
Stephen Boyd <sboyd@kernel.org>,
Philipp Zabel <p.zabel@pengutronix.de>,
Fan Chen <fan.chen@mediatek.com>,
HenryC Chen <HenryC.Chen@mediatek.com>,
YT Lee <yt.lee@mediatek.com>,
Xiaoqing Liu <Xiaoqing.Liu@mediatek.com>,
Charles Yang <Charles.Yang@mediatek.com>,
Angus Lin <Angus.Lin@mediatek.com>,
Mark Rutland <mark.rutland@arm.com>, Nishanth Menon <nm@ti.com>,
devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-pm@vger.kernel.org,
Project_Global_Chrome_Upstream_Group@mediatek.com
Subject: Re: [PATCH v16 3/7] soc: mediatek: SVS: introduce MTK SVS engine
Date: Thu, 13 May 2021 20:33:14 -0700 [thread overview]
Message-ID: <ec5f064f-41f1-f8f9-9a6d-fdf02c43cb8d@roeck-us.net> (raw)
In-Reply-To: <7a7a07adedf5d3f430fecf81aed35c6321e5b634.camel@mediatek.com>
On 5/13/21 8:10 PM, Roger Lu wrote:
> Hi Guenter,
>
> Sorry for the late reply and thanks for the notice.
>
> On Wed, 2021-05-05 at 21:51 -0700, Guenter Roeck wrote:
>> On Wed, Apr 28, 2021 at 02:54:36PM +0800, Roger Lu wrote:
>>> The Smart Voltage Scaling(SVS) engine is a piece of hardware
>>> which calculates suitable SVS bank voltages to OPP voltage table.
>>> Then, DVFS driver could apply those SVS bank voltages to PMIC/Buck
>>> when receiving OPP_EVENT_ADJUST_VOLTAGE.
>>>
>>> Signed-off-by: Roger Lu <roger.lu@mediatek.com>
>>> ---
>>> drivers/soc/mediatek/Kconfig | 10 +
>>> drivers/soc/mediatek/Makefile | 1 +
>>> drivers/soc/mediatek/mtk-svs.c | 1723
>>> ++++++++++++++++++++++++++++++++
>>> 3 files changed, 1734 insertions(+)
>>> create mode 100644 drivers/soc/mediatek/mtk-svs.c
>>>
>>
>> [ ... ]
>>
>>> +
>>> + svsp_irq = irq_of_parse_and_map(svsp->dev->of_node, 0);
>>> + ret = devm_request_threaded_irq(svsp->dev, svsp_irq, NULL,
>>> svs_isr,
>>> + svsp->irqflags, svsp->name,
>>> svsp);
>>
>> 0-day reports:
>>
>> drivers/soc/mediatek/mtk-svs.c:1663:7-32: ERROR:
>> Threaded IRQ with no primary handler requested without
>> IRQF_ONESHOT
>>
>> I would be a bit concerned about this. There is no primary (hard)
>> interrupt handler, meaning the hard interrupt may be re-enabled after
>> the default hard interrupt handler runs. This might result in endless
>> interrupts.
>
> Oh, we add IRQF_ONESHOT in "svs_get_svs_mt8183_platform_data()" for
> threaded irq. So, please kindly let us know if we need to set more
> flags or any other potential risks we should be aware. Thanks in
> advance.
>
After reviewing the code, I think this was actually a false alarm,
at least if svsp->irqflags always includes IRQF_ONESHOT.
The code is kind of unusual, though. Unless I am missing something,
svsp->irqflags is only set in one place and it is always set
to IRQF_TRIGGER_LOW | IRQF_ONESHOT. If there is a remote chance
that the flag is ever different, it would have been better (and less
confusing) to specify IRQF_ONESHOT directly when requesting the
interrupt (because it is always needed, no matter which SOC).
If the flags are always the same, there is no reason for having
the svsp->irqflags variable in the first place.
Thanks,
Guenter
next prev parent reply other threads:[~2021-05-14 3:33 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-28 6:54 [PATCH v16 0/7] soc: mediatek: SVS: introduce MTK SVS Roger Lu
2021-04-28 6:54 ` [PATCH v16 1/7] dt-bindings: soc: mediatek: add mtk svs dt-bindings Roger Lu
2021-04-28 6:54 ` [PATCH v16 2/7] arm64: dts: mt8183: add svs device information Roger Lu
2021-10-20 15:20 ` AngeloGioacchino Del Regno
2021-12-24 7:33 ` Roger Lu
2021-12-30 12:54 ` Matthias Brugger
2022-01-03 6:08 ` Roger Lu
2021-04-28 6:54 ` [PATCH v16 3/7] soc: mediatek: SVS: introduce MTK SVS engine Roger Lu
2021-05-06 4:51 ` Guenter Roeck
2021-05-14 3:10 ` Roger Lu
2021-05-14 3:33 ` Guenter Roeck [this message]
2021-05-14 5:58 ` Roger Lu
2021-10-21 8:46 ` AngeloGioacchino Del Regno
2021-12-24 9:27 ` Roger Lu
2021-12-24 9:34 ` AngeloGioacchino Del Regno
2021-04-28 6:54 ` [PATCH v16 4/7] soc: mediatek: SVS: add debug commands Roger Lu
2021-10-21 8:52 ` AngeloGioacchino Del Regno
2021-12-24 9:38 ` Roger Lu
2021-04-28 6:54 ` [PATCH v16 5/7] dt-bindings: soc: mediatek: add mt8192 svs dt-bindings Roger Lu
2021-04-28 6:54 ` [PATCH v16 6/7] arm64: dts: mt8192: add svs device information Roger Lu
2021-10-20 15:16 ` AngeloGioacchino Del Regno
2021-12-24 9:42 ` Roger Lu
2021-10-20 15:18 ` AngeloGioacchino Del Regno
2021-04-28 6:54 ` [PATCH v16 7/7] soc: mediatek: SVS: add mt8192 SVS GPU driver Roger Lu
2021-05-14 3:20 ` YT Lee
2021-10-21 9:08 ` AngeloGioacchino Del Regno
2021-12-30 13:18 ` [PATCH v16 0/7] soc: mediatek: SVS: introduce MTK SVS Matthias Brugger
2022-01-03 7:43 ` Roger Lu
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