X1 Boot Issue

[lktan-adft]

Symptoms

• X1 power light is working fine.
• X1 MB run light is not blinking

Study

Following are the logs that received from the debug pin (J11)

Failed

AT91Bootstrap 3.8.8-g4a156b8 (Isn Sep 21 20:58:34 +08 2020)

SD/MMC: Image: Read file u-boot.bin to 0x26f00000
SD: Card Capacity: High or Extended
SD: Specification Version 3.0X
SDHC: Transfer data timeout
*** FATFS: f_open, filename: [u-boot.bin]: error
SD/MMC: Failed to load image  

Success

AT91Bootstrap 3.8.8-g4a156b8 (Isn Sep 21 20:58:34 +08 2020)

SD/MMC: Image: Read file u-boot.bin to 0x26f00000
SD: Card Capacity: High or Extended
SD: Specification Version 3.0X
SD/MMC: Done to load image
<debug_uart>

U-Boot 2017.03-linux4sam_5.6-gd0f231c-dirty (Sep 21 2020 - 20:59:15 +0800)

CPU: SAMA5D22-CU
Crystal frequency:       12 MHz
CPU clock        :      498 MHz
Master clock     :      166 MHz
DRAM:  256 MiB
MMC:   sdio-host@b0000000: 0
In:    serial
Out:   serial
Err:   serial
Net:   eth0: ethernet@f8008000
Hit any key to stop autoboot:  0
...

Issue:

• Looking from the log, it seems the board already loaded boot.bin (through internal rom program) and failed to load the u-boot.bin.
• Suspect it might be software timing issue as the internal rom program able to interface with the SD card and loaded boot.bin

some similar reported issue:

https://github.com/linux4sam/at91bootstrap/issues/98

Further works:

• An starting point would be following the github issue to enable the verborse debug message to look into the problem (as mentioned by the issue discussion).

Can you enable CONFIG_DEBUG_VERY_LOUD, and also update your bootstrap to 3.8.13
then copy the boot log ?

• Then could be debug further on what possible issue
• A wild test also could be done to upgrade our current at91bootstrap code to the lastest release

[lktan-adft]

Probably hardware issue,

• Initially SD Card access is in one bit mode, for setting up the SD Card and handshaking process
• The SD Card communication timeout happens when the SD Card bus mode changed to 4 bit
• Changed the at91bootstrap code force it to maintain one bit mode
• Able to load the u-boot.bin but it failed during the kernel stage, as it not able to detect the SD Card.
• Suspected would be X1 hardware issue, might be certain SD Card data bus trace is not working.