imx8 nano - usdhc3( emmc ) reset

[razriel]

Our custom board is based on imx8mn-ddr4-evk with slight modifications.

Currently board is loading u-boot, kernel and rootfs when boot mode is set to SD-CARD and usdhc3 ( is disabled)

When udshc3( emmc ) is enabled in device tree the u-boot fails. system restart without any warnning in debug terminal.

We have verified pins allocation and routing of eMMC is same as refrence design. We are having hard time to figure out what causes the target board to restart during the run of the u-boot.

This issue prevents us from being able to flash the emmc from uuu in boot download mode. Our goal is to  be able to load the system from eMMC boot mode.

Next step we plan is to connect Jlink/JTAG to run u-boot step by step and learn where the firmware crashes. 

please help if you have any idea what can cause such a behaviour. 

[Rita_Wang]

For your design you need to enable the usdhc3 in the software then it can work. Here you can refer to https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/Enabling-uSDHC1-of-i-MX8MM-Based-On-L5-4... this threads. It will help you.

[razriel]

ushdc3 is enabled and working on EVK. same pinout same flash part number on target board. but on target board it crashes in the middle of u-boot run. the is no message in debug terminal before it restarts.

[Rita_Wang]

Have you finished all the configuration for the EMMC? And when you download image to emmc, is there information on the debug terminal?