AM3352: Start u-boot from uSD

For your reference, the u-boot configuration <am335x_evm_defconfig> is for building u-boot for booting from SD/NAND etc…on TI AM335x EVMs.

https://software-dl.ti.com/processor-sdk-linux/esd/docs/06_03_00_106/AM335X/linux/Foundational_Components_U-Boot.html#build-and-boot-flow-on-32-bit-platforms

Hello,

Thank you for your response.

That is the config file I am using. I have changed board specific files to adapt u-boot to our HW, and it is runnig from NAND flash.

The same changes we did for previous u-boot version and this one works from NAND and SD.

Are there specific settings for starting from SD?

Best regards and thank you

Angel

Have you checked the SYSBOOT pin setup to have MMD to be in booting device list?

Do we have any visibility (i.e. log) to indicate booting progress?

Will you check u-boot bring-up tips as outlined in the link below:

https://software-dl.ti.com/processor-sdk-linux/esd/docs/06_03_00_106/AM335X/linux/How_to_Guides/Board_Port/U-Boot.html#u-boot-bringup-debugging-tips

Hello,

SYSBOOT pin setup is correct. As I mentioned, previous u-boot version works fine both from NAND FLASH and from uSD.

Nothing is shown on the console. Up to now all I can say is that function board_init_f() from ctr0.S is called and executed. After that I do not know what is happening.

I checked bring-up tips and changes are the same made in previous u-boot version to port it to our HW.

Best regards

Angel

Hi Angel,

Is there a JTAG available on your board? If yes, JTAG debugger would be helpful for early boot up issue, where no console output available.

Best,

-Hong

Hi Hong,

I am sorry but JTAG is not available. System is not starting from uSD because calling to function boot_from_devices() in board_init_r() (spl.c file) is returning -ENODEV, so start-up process is hang.

But, up to now, I do not know why this happens only when starting from uSD.

I am trying to enable console from SPL following instructions from README file, but it is not working. I have set CONFIG_SPL_BOARD_INIT and then preloader_console_init() is called from spl_board_init(), but console is not working.

I think this could help to debug this issue.

Best regards

Angel

Hi Angel,

Will you be able to modify SYSBOOT pin on-board to include UART boot mode into booting device list?

If yes, can we watch if "cccc...." from serial terminal output from rom code peripheral boot (i.e. UART).

Also some useful tips on debugging early boot up issues can be referenced 

https://processors.wiki.ti.com/index.php/AM335x_board_bringup_tips

Best,

-Hong

Hi Hong,

Sorry, but HW is stable for a long time and I can not change SYSBOOT pin.

Now I have removed CONFIG_SPL_BLK and CONFIG_BLK from am335x_evm_defconfig file, I have changed "#if !CONFIG_IS_ENABLED(DM_MMC)" to "#ifndef CONFIG_DM_MMC" and "#if CONFIG_IS_ENABLED(DM_MMC)" to "#ifdef CONFIG_DM_MMC" and it starts up to the u-boot prompt.

The problem is I can not access the MMC device format:

=> mmc info
Device: OMAP SD/MMC
Manufacturer ID: 3
OEM: 5344
Name: SC32G
Bus Speed: 48000000
Mode : SD High Speed (50MHz)
Rd Block Len: 512
SD version 3.0
High Capacity: Yes
Capacity: 29.7 GiB
Bus Width: 4-bit
Erase Group Size: 512 Bytes
=>

=> fatload mmc 0 0x82000000 MLO
** Unrecognized filesystem type **
=>

The problem is that when calling "disk_read(0, 1, buffer)" in fat_set_blk_dev() function, read data is all 0x00.

Can you help us with this?

Best regards

Angel