Yocto hangs while booting for imx6 custom board

[pratyushtomar]

We have made a custom board and we were able to download image to board(emmc and lpddr2 ram). If we use default Mfg tool zImage and zImage-imx6ul-14x14-evk-emmc.dtb the board successfully boots but if we use our own customised zImage and dtb file the board hangs while booting showing last message "waiting for root device /dev/mmcblk1p2". While same image was working fine with imx6 evk board(sdcard). I have attached the dts file I am using for my customised board(lpddr2 ram and emmc). Where I am making a mistake in my dts file which leads to board hang up while booting.

Original Attachment has been moved to: imx6ul-14x14-evk.dts.zip

[igorpadykov · Accepted solution]

Hi Pratyush

in attached dts file usdhc1 is commented out, so only usdhc2 is

available. In this case numbering may change to /dev/mmcblk0p2,

please refer to attached Linux Guide Table 31. Linux uSDHC relationships.

Also recommended to check with oscilloscope if correct sd

interface and all 8 data lines are toggled.

Regarding :

>if we use our own customised zImage and dtb file the board hangs while booting showing last message "waiting for root >device /dev/mmcblk1p2". While same image was working fine with imx6 evk board(sdcard). 

it is strange that it is working with imx6 evk board (as it has 4 bit sd interface)

while you made sd configuration for 8 bit.

In general one can debug it using AN4553 Using Open Source Debugging Tools for

Linux on i.MX Processors sect.8.1 Debugging the Kernel Boot Phase

http://www.nxp.com/files/32bit/doc/app_note/AN4553.pdf 

and enabling early printk

https://community.nxp.com/thread/351167 

Best regards
igor
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