supporting UHS-I in imx6 board by yocto L4.1.15

[qi908542785]

Hi,

We are using a Sabresd board (i.MX6Q) with YOCTO 4.1.15 kernel. The host supports UHS-I SDR 50 and 104 modes. However when we plug in a UHS-I SD card to usdhc3, we see that it gets detected as a "High speed device" rather than a 'ultra high speed device'. Browsing through the sources, we found that to for the SD card to work in UHS mode, the host needs to switch to 1.8v from 3.3v.

Looks like Sabresd does not support this voltage level and hence restricts this switch over.

Then, I found the following posts talk about 1.8V SD/MMC.But I failed.

What need to modify the support UHS-I mode,Also need to make some changes in u-boot.Hope to get your help.

supporting SDR104 in imx6 board by yocto

Regards,

QI.

[igorpadykov]

Hi

Sabresd board has not 1.8V switch, depicted on mentioned link

as AI board schematic. So it does not support SDR104.

For SDR104 testing one can use Sabre AI board which has such switch.

Best regards

igor

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[qi908542785]

Hi

Our products use Sabresd board,On the basis of Sabresd board, do your own board.

On the basis of Sabresd board,Whether can do some modification on the hardware to support UHS-I mode

Do you have any good ways to make Sabresd board support UHS-I mode?

Best regards

igor

[jan_spurek]

Hi,

to enable SDR50/SDR104 mode, you need to acces BOOT_CFG1[3:2] and choose either value 10 (SDR50) or 11 (SDR104). Refference manual, page 345. BOOT_CFG1[3:2] can be accesed via EIM_DA2 (BOOT_CFG1[2]) and EIM_DA3  (BOOT_CFG1[3])  pins.

[igorpadykov]

Hi

please implement on custom board switch which uses Sabre AI board.

Best regards

igor