How to set HS400 mode of eMMC from uboot in i.MX 8M Quad EVK?

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How to set HS400 mode of eMMC from uboot in i.MX 8M Quad EVK?

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kyungsik_lee
Contributor I

I'm using i.MX 8M Quad EVK board and then found eMMC is not set to HS400 mode.

u-boot=> mmc info
Device: FSL_SDHC
Manufacturer ID: 13
OEM: 14e
Name: R1J56
Bus Speed: 52000000
Mode : MMC DDR52 (52MHz)
Rd Block Len: 512
MMC version 5.0
High Capacity: Yes
Capacity: 13.8 GiB
Bus Width: 8-bit DDR
Erase Group Size: 512 KiB
HC WP Group Size: 8 MiB
User Capacity: 13.8 GiB WRREL
Boot Capacity: 4 MiB ENH
RPMB Capacity: 128 KiB ENH

But after booting is complete, kernel shows that eMMC is set to HS400.

evk_8mq:/ # cat /sys/kernel/debug/mmc0/ios
clock: 200000000 Hz
actual clock: 200000000 Hz
vdd: 21 (3.3 ~ 3.4 V)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 3 (8 bits)
timing spec: 10 (mmc HS400)
signal voltage: 1 (1.80 V)
driver type: 0 (driver type B)

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1 Solution
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igorpadykov
NXP Employee
NXP Employee

Hi Andy

seems i.MX8M does not support emmc hs400 boot option as described in

Table 6-14. USDHC boot eFUSE descriptions i.MX8MDQ Reference Manual
https://www.nxp.com/docs/en/reference-manual/IMX8MDQLQRM.pdf

One can try to port mmc linux driver (description can be found in sect.3.3 MMC/SD/SDIO

Host attached Linux Manual) for enabling hs400 in uboot.

Best regards
igor
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1 Reply
3,009 Views
igorpadykov
NXP Employee
NXP Employee

Hi Andy

seems i.MX8M does not support emmc hs400 boot option as described in

Table 6-14. USDHC boot eFUSE descriptions i.MX8MDQ Reference Manual
https://www.nxp.com/docs/en/reference-manual/IMX8MDQLQRM.pdf

One can try to port mmc linux driver (description can be found in sect.3.3 MMC/SD/SDIO

Host attached Linux Manual) for enabling hs400 in uboot.

Best regards
igor
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------