From: Kevin Hilman <khilman@baylibre.com>
To: Rex-BC Chen <rex-bc.chen@mediatek.com>,
rafael@kernel.org, viresh.kumar@linaro.org, robh+dt@kernel.org,
krzk+dt@kernel.org, matthias.bgg@gmail.com
Cc: jia-wei.chang@mediatek.com, roger.lu@mediatek.com,
hsinyi@google.com, angelogioacchino.delregno@collabora.com,
linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org,
Project_Global_Chrome_Upstream_Group@mediatek.com,
Rex-BC Chen <rex-bc.chen@mediatek.com>
Subject: Re: [PATCH V3 11/15] cpufreq: mediatek: Link CCI device to CPU
Date: Wed, 20 Apr 2022 11:09:59 -0700 [thread overview]
Message-ID: <7hv8v3eidk.fsf@baylibre.com> (raw)
In-Reply-To: <20220415055916.28350-12-rex-bc.chen@mediatek.com>
Hi Rex,
Rex-BC Chen <rex-bc.chen@mediatek.com> writes:
> From: Jia-Wei Chang <jia-wei.chang@mediatek.com>
>
> In some MediaTek SoCs, like MT8183, CPU and CCI share the same power
> supplies. Cpufreq needs to check if CCI devfreq exists and wait until
> CCI devfreq ready before scaling frequency.
>
> Before CCI devfreq is ready, we record the voltage when booting to
> kernel and use the max(cpu target voltage, booting voltage) to
> prevent cpufreq adjust to the lower voltage which will cause the CCI
> crash because of high frequency and low voltage.
>
> - Add is_ccifreq_ready() to link CCI device to CPI, and CPU will start
> DVFS when CCI is ready.
> - Add platform data for MT8183.
>
> Signed-off-by: Jia-Wei Chang <jia-wei.chang@mediatek.com>
> Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
The solution of keeping the max of the CPU voltage from OPP and boot-up
voltage makes sense until CCI is ready. Thank you for the rework and
the detailed technical explanations.
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Kevin
next prev parent reply other threads:[~2022-04-20 18:10 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-15 5:59 [PATCH V3 00/15] cpufreq: mediatek: Cleanup and support MT8183 and MT8186 Rex-BC Chen
2022-04-15 5:59 ` [PATCH V3 01/15] dt-bindings: cpufreq: mediatek: Add MediaTek CCI property Rex-BC Chen
2022-04-15 5:59 ` [PATCH V3 02/15] cpufreq: mediatek: Use device print to show logs Rex-BC Chen
2022-04-15 12:24 ` AngeloGioacchino Del Regno
2022-04-15 5:59 ` [PATCH V3 03/15] cpufreq: mediatek: Replace old_* with pre_* Rex-BC Chen
2022-04-15 12:24 ` AngeloGioacchino Del Regno
2022-04-15 5:59 ` [PATCH V3 04/15] cpufreq: mediatek: Record previous target vproc value Rex-BC Chen
2022-04-15 12:24 ` AngeloGioacchino Del Regno
2022-04-18 1:37 ` Rex-BC Chen
2022-04-15 5:59 ` [PATCH V3 06/15] cpufreq: mediatek: Move voltage limits to platform data Rex-BC Chen
2022-04-15 12:24 ` AngeloGioacchino Del Regno
2022-04-15 5:59 ` [PATCH V3 07/15] cpufreq: mediatek: Add .get function Rex-BC Chen
2022-04-15 5:59 ` [PATCH V3 08/15] cpufreq: mediatek: Make sram regulator optional Rex-BC Chen
2022-04-15 5:59 ` [PATCH V3 09/15] cpufreq: mediatek: Refine mtk_cpufreq_voltage_tracking() Rex-BC Chen
2022-04-15 5:59 ` [PATCH V3 10/15] cpufreq: mediatek: Add counter to prevent infinite loop when tracking voltage Rex-BC Chen
2022-04-15 6:14 ` Hsin-Yi Wang
2022-04-15 6:29 ` Rex-BC Chen
2022-04-15 12:24 ` AngeloGioacchino Del Regno
2022-04-18 1:40 ` Rex-BC Chen
2022-04-15 5:59 ` [PATCH V3 11/15] cpufreq: mediatek: Link CCI device to CPU Rex-BC Chen
2022-04-15 12:24 ` AngeloGioacchino Del Regno
2022-04-18 1:45 ` Rex-BC Chen
2022-04-20 18:09 ` Kevin Hilman [this message]
2022-04-15 5:59 ` [PATCH V3 12/15] cpufreq: mediatek: Add support for MT8186 Rex-BC Chen
2022-04-15 5:59 ` [PATCH V3 13/15] arm64: dts: mediatek: Add opp table and clock property for MT8183 cpufreq Rex-BC Chen
2022-04-15 12:24 ` AngeloGioacchino Del Regno
2022-04-18 1:46 ` Rex-BC Chen
2022-04-15 5:59 ` [PATCH V3 14/15] arm64: dts: mediatek: Add MediaTek CCI node for MT8183 Rex-BC Chen
2022-04-15 6:06 ` Hsin-Yi Wang
2022-04-15 6:10 ` Hsin-Yi Wang
2022-04-15 12:23 ` AngeloGioacchino Del Regno
2022-04-15 5:59 ` [PATCH V3 15/15] arm64: dts: mediatek: Add mediatek,cci property for MT8183 cpufreq Rex-BC Chen
2022-04-15 12:23 ` AngeloGioacchino Del Regno
[not found] ` <20220415055916.28350-6-rex-bc.chen@mediatek.com>
2022-04-15 12:24 ` [PATCH V3 05/15] cpufreq: mediatek: Add opp notification support AngeloGioacchino Del Regno
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