We have changed from an SDcard to eMMC as we want to use the higher spped that eMMC could provide.
We use the Toschiba THGBMHG6C1LBAIL chip.
Due to design limitations we just could use 4Bit and not 8Bit.
Nevertheless we expect a much higher data troughput rate as this chip supprts HS400 data rate.
But we could not find any support in the board support package to swicht to Jedec HS200 or HS400 data rates.
Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt
The Linux-Kernel device tree we found here
Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt
In the DeviceTree ./arch/arm/boot/dts/am335x-sps-revA.dts is this section related to
/* eMMC */
&mmc1 {
status = "okay";
vmmc-supply = <&vmmc_reg>;
bus-width = <4>;
pinctrl-names = "default"; //, "sleep";
pinctrl-0 = <&mmc1_pins_default>;
pinctrl-1 = <&mmc1_pins_default>; // <&mmc1_pins_sleep>;
ti,non-removable; // non-removable slot (like eMMC)
// cap-mmc-dual-data-rate; // MMC High Speed Dual Data Rate mode supported at 1.8V/3V signaling
// cap-mmc-highspeed; // MMC high-speed timing is supported
};
The cap-mmc-dual-data-rate and cap-mmc-highspeed look lick options to boost but didn't work.
We could not startup the linux when we enable that settings.
So my question is, ist there a driver update or a batch availeable that supports HS200 or HS 400 for a 4Bit eMMC.
Regards Bernd
