Messages in this thread | | | Date | Tue, 3 Oct 2023 11:24:38 +0200 | Subject | Re: [PATCH] arm64: dts: mediatek: mt8195: Set DSU PMU status to fail | From | AngeloGioacchino Del Regno <> |
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Il 20/07/23 22:07, Nícolas F. R. A. Prado ha scritto: > The DSU PMU allows monitoring performance events in the DSU cluster, > which is done by configuring and reading back values from the DSU PMU > system registers. However, for write-access to be allowed by ELs lower > than EL3, the EL3 firmware needs to update the setting on the ACTLR3_EL3 > register, as it is disallowed by default. > > That configuration is not done on the firmware used by the MT8195 SoC, > as a consequence, booting a MT8195-based machine like > mt8195-cherry-tomato-r2 with CONFIG_ARM_DSU_PMU enabled hangs the kernel > just as it writes to the CLUSTERPMOVSCLR_EL1 register, since the > instruction faults to EL3, and BL31 apparently just re-runs the > instruction over and over. > > Mark the DSU PMU node in the Devicetree with status "fail", as the > machine doesn't have a suitable firmware to make use of it from the > kernel, and allowing its driver to probe would hang the kernel. > > Fixes: 37f2582883be ("arm64: dts: Add mediatek SoC mt8195 and evaluation board") > Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com> >
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
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