Messages in this thread | | | From | Kevin Hilman <> | Subject | Re: [PATCH V3 11/15] cpufreq: mediatek: Link CCI device to CPU | Date | Wed, 20 Apr 2022 11:09:59 -0700 |
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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
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