H616: enable sd card reader UHS-I support

[mdziekon]

Note for myself

---

Legacy kernel (4.9) supports SD reader with UHS enabled for better SD card IO performance: https://github.com/orangepi-xunlong/linux-orangepi/blob/orange-pi-4.9-sun50iw9/arch/arm64/boot/dts/sunxi/sun50i-h616-orangepi-zero2.dts#L3346-L3348 (as used by Armbian here: https://github.com/armbian/build/blob/59363d5a0f1a833bb54efbde0831a2e3f6626c8a/config/sources/families/sun50iw9.conf#L21-L23) (verified with cat /sys/kernel/debug/mmc0/ios and some basic performance testing)

However, newer kernels do not have this caps enabled.

Trying to enable them on Armbian edge (currently, kernel 6.2.x) via adding the following DTS attributes:

 &mmc0 {
        vmmc-supply = <&reg_dcdce>;
+       vqmmc-supply = <&reg_bldo1>;
        cd-gpios = <&pio 5 6 GPIO_ACTIVE_LOW>;  /* PF6 */
        bus-width = <4>;
        status = "okay";
+       sd-uhs-sdr50;
+       sd-uhs-ddr50;
+       sd-uhs-sdr104;
+       mmc-ddr-1_8v;
 };

results in the board being unable to boot due to -110 ERROR while trying to find the file system.

Looking deeper into the driver's code, the driver reaches at best this place in code: https://github.com/torvalds/linux/blob/v6.2/drivers/mmc/core/core.c#L1248-L1253

So, with my limited knowledge, it looks like the device was unable to switch to 1.8V mode.

[AGM1968]

Hi Michal, if you've not already seen, these are added to h616.dtsi

-           max-frequency = <150000000>;
            cap-sd-highspeed;
            cap-mmc-highspeed;
            mmc-ddr-3_3v;
+           mmc-ddr-1_8v;
            cap-sdio-irq;
            #address-cells = <1>;
            #size-cells = <0>;

[mdziekon]

@AGM1968 hi, no, unfortunatelly I haven't seen this change you're mentioning. I can't see it neither in current main of armbian, nor in current master of Linux itself. Could you please point me to the place you've found such thing?

[AGM1968]

Hi Michal, if you go to >>

/build/cache/sources/linux-kernel-worktree/6.2_sunxi64_arm64/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi

you'll find where to add mmc-ddr-1_8v

I've really not looked at all on this but just thought that might be the problem from memory of dtsi.

Hope it helps

Mainline as follows >>

https://github.com/AGM1968/linux/blob/929ed21dfdb6ee94391db51c9eedb63314ef6847/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi#L277-L281

[mdziekon]

@AGM1968 ok, I think I understand what you meant.

However, isn't that the same as adding it to &mmc0, in cache/sources/linux-kernel-worktree/6.2__sunxi64__arm64/arch/arm64/boot/dts/allwinner/sun50i-h616-orangepi-zero2.dts (because that's where I put the patch from the original comment, it's just a simplified version)? As far as I understand, in sun50i-h616-orangepi-zero2.dts we're essentially creating overwrites for specific dts entries in the base definitions (in this case that would be sun50i-h616.dtsi). So in general, I think it shouldn't matter whether I'll make the change in sun50i-h616.dtsi or in sun50i-h616-orangepi-zero2.dts, right?

[AGM1968]

There may be issues during the compile process with the includes. I've only seen the reference added to the dtsi.

[mdziekon]

Ok, understood, thanks for explaining that. In that case, I'll definitely try the other way once I have some spare time.

[AGM1968]

Yeah Im only guessing really, but that's the most likely explanation.

Try earlycon when you boot, not sure how you debugging.

Best, Alistair