The IMX8M reference manuals indicate in the USDHC Clock generator section that the clock rate for DDR is 1/2 the input clock therefore HS400 rates clocked at 200Mhz require a 400Mhz SDHC clock.
This showed about a 1.5x improvement in read performance for the eMMC's used on the various imx8m{m,n,p}-venice boards.
Fixes: a72ba91e5bc7 ("arm64: dts: imx: Add i.mx8mm Gateworks gw7903 dts support") Signed-off-by: Tim Harvey tharvey@gateworks.com --- arch/arm64/boot/dts/freescale/imx8mm-venice-gw7903.dts | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/arm64/boot/dts/freescale/imx8mm-venice-gw7903.dts b/arch/arm64/boot/dts/freescale/imx8mm-venice-gw7903.dts index c0aadff4e25b..636daa3d6ca2 100644 --- a/arch/arm64/boot/dts/freescale/imx8mm-venice-gw7903.dts +++ b/arch/arm64/boot/dts/freescale/imx8mm-venice-gw7903.dts @@ -621,6 +621,8 @@ &usdhc3 { pinctrl-0 = <&pinctrl_usdhc3>; pinctrl-1 = <&pinctrl_usdhc3_100mhz>; pinctrl-2 = <&pinctrl_usdhc3_200mhz>; + assigned-clocks = <&clk IMX8MM_CLK_USDHC3>; + assigned-clock-rates = <400000000>; bus-width = <8>; non-removable; status = "okay";