How to boot from eMMC?

daniel_gomez — Tue, 18 Dec 2018 11:06:33 GMT

Hi,

We've created a custom board based in IMX6Q, but we've problems botting from the eMMC connected to SD4.

We run the u-boot and kernel from MFGTOOLs everythings works correctly, but the system doesn't start from eMMC. We're using kernel 4.9.11 and uboot2015 from OpenRex, with this boot configuration registers:

BOOT_CFG1[7:6] : 01 - boot from USDHC
BOOT_CFG1[5] : 1 - eMMC
BOOT_CFG1[4] : 0 - Normal boot
BOOT_CFG1[3:2] : 00 - High speed mode
BOOT_CFG1[1] : 0 - eMMC reset disable
BOOT_CFG1[0] : 0 - Throught the SD pad
BOOT_CFG2[7:5] : 010 - 8bit DDR
BOOT_CFG2[4:3] : 11 - USDHC-4
BOOT_CFG2[2] : 0 - Boot ROM default
BOOT_CFG2[1] : 0 - Boot acknowledge enable
BOOT_CFG2[0] : 0 - Use default values

To review if we're doing it correctly, we use the command ‘mmc extcsd read <device>’ getting the output attached.

For initializing the eMMC we use these commands:

dd if=/dev/zero of=/dev/mmcblk3 bs=1k seek=384 conv=fsync count=129
echo 0 > /sys/block/mmcblk3boot0/force_ro
dd if=u-boot.imx of=/dev/mmcblk3boot0 bs=512 seek=2
echo 1 > /sys/block/mmcblk3boot0/force_ro
mmc bootpart enable 1 1 /dev/mmcblk3boot0

Any hint would be appreciated.

Thanks in advance!

Re: How to boot from eMMC?

igorpadykov — Wed, 19 Dec 2018 01:32:36 GMT

Hi Daniel

emmc on USDHC4 port is supported on i.MX6Q Sabre SD board:

Schematics (1)
i.MX6_SABRE_SDP_DESIGNFILES
http://www.nxp.com/products/software-and-tools/hardware-development-tools/sabre-development-system/sabre-platform-for-smart-devices-based-on-the-i.mx-6-series:RDIMX6SABREPLAT?fpsp=1&tab=Design_Tools_Tab

One can flash image using mfg tool (use mfgtool2-yocto-mx-sabresd-emmc.vbs script)

and following documentation from link:

https://www.nxp.com/support/developer-resources/run-time-software/i.mx-developer-resources/i.mx-6series-i.mx-7series-software-and-development-tool-resources:IMX_SW

Best regards
igor
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