Some bootloaders will set MSDCPLL's rate lower than 400MHz: what I have
seen is this clock being set at around 384MHz.
This is a performance concern (and possibly a stability one, for picky
eMMC/SD cards) as the MSDC controller's internal divier will choose a
frequency that is lower than expected, in the end causing a difference
in the expected mmc/sd device's timings.
Make sure that the MSDCPLL frequency is always set to 400MHz to both
improve performance and reliability of the sd/mmc storage.
Fixes: 37f2582883be ("arm64: dts: Add mediatek SoC mt8195 and evaluation board")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
---
arch/arm64/boot/dts/mediatek/mt8195.dtsi | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm64/boot/dts/mediatek/mt8195.dtsi b/arch/arm64/boot/dts/mediatek/mt8195.dtsi
index a44aae4ab953..daac8e050ce7 100644
--- a/arch/arm64/boot/dts/mediatek/mt8195.dtsi
+++ b/arch/arm64/boot/dts/mediatek/mt8195.dtsi
@@ -852,6 +852,8 @@ apmixedsys: syscon@1000c000 {
compatible = "mediatek,mt8195-apmixedsys", "syscon";
reg = <0 0x1000c000 0 0x1000>;
#clock-cells = <1>;
+ assigned-clocks = <&apmixedsys CLK_APMIXED_MSDCPLL>;
+ assigned-clock-rates = <400000000>;
};
systimer: timer@10017000 {
--
2.40.1
