Re: [PATCH v2 7/9] clk: samsung: exynos850: Implement CMU_MFCMSCL domain
From: Krzysztof Kozlowski
Date: Fri Aug 12 2022 - 05:55:55 EST
On 09/08/2022 14:33, Sam Protsenko wrote:
> CMU_MFCMSCL clock domain provides clocks for MFC (Multi-Format Codec),
> JPEG Codec and Scaler IP-cores. According to Exynos850 TRM, CMU_MFCMSCL
> generates MFC, M2M, MCSC and JPEG clocks for BLK_MFCMSCL.
>
> This patch adds next clocks:
> - bus clocks in CMU_TOP for CMU_MFCMSCL
> - all internal CMU_MFCMSCL clocks
> - leaf clocks for MFCMSCL, TZPC (TrustZone Protection Controller),
> JPEG codec, M2M (Memory-to-Memory), MCSC (Multi-Channel Scaler),
> MFC (Multi-Format Codec), PPMU (Platform Performance Monitoring
> Unit), SysMMU and SysReg
>
> MFCMSCL related gate clocks in CMU_TOP were marked as CLK_IS_CRITICAL,
> because:
> 1. All of those have to be enabled in order to read
> /sys/kernel/debug/clk/clk_summary file
> 2. When some user driver (e.g. exynos-sysmmu) disables some derived
> leaf clock, it can lead to CMU_TOP clocks disable, which then makes
> the system hang. To prevent that, the CLK_IS_CRITICAL flag is used,
> as CLK_IGNORE_UNUSED is not enough.
No, same as with ISP these are not critical clocks.
Best regards,
Krzysztof