Linux/AM3358: No boot messages on UART

Preetam Reddy

Intellectual 635 points

Part Number: AM3358

Tool/software: Linux

I have a custom am3358 board with emmc and peripherals. This is a production board for a product.

I have a socketed e.mmc which I have partitoned to

Boot : 200MiB fat32 with boot , lba flags. MLO and U-boot files copied over.

Rootfs : rest of the 14 GiB ext4, nothing present in here yet.

When I put the e.mmc on board and boot, it shows nothing on uart. absolute blank.

If I boot the board without the e.MMC it shows 'CCCC'

Whats causing it and how do I debug and get my bringup started.

over 6 years ago

0 Biser Gatchev-XID over 6 years ago

TI__Guru**** 393215 points

Where is the eMMC connected? MMC0 or MMC1?

0 Biser Gatchev-XID over 6 years ago in reply to Biser Gatchev-XID

TI__Guru**** 393215 points

Which Linux version are you using?

0 Preetam Reddy over 6 years ago in reply to Biser Gatchev-XID

Intellectual 635 points

I am still working to boot MLO, let alone u-boot. I am not loading any kernel just yet.

0 Preetam Reddy over 6 years ago in reply to Biser Gatchev-XID

Intellectual 635 points

The schematics say GPMC_AD0 to GPMC_AD7.

So MMC 1 is e.mmc and mmc 0 seems to be WLAN chipset.

0 Biser Gatchev-XID over 6 years ago in reply to Preetam Reddy

TI__Guru**** 393215 points

Preetam Reddy said:
I am still working to boot MLO, let alone u-boot. I am not loading any kernel just yet.

Nevertheless, is this the Linux Processor SDK provided by TI, or some other version?

0 Biser Gatchev-XID over 6 years ago in reply to Preetam Reddy

TI__Guru**** 393215 points

Preetam Reddy said:
The schematics say GPMC_AD0 to GPMC_AD7. So MMC1 is e.mmc and mmc 0 seems to be WLAN chipset.

This seems to be OK then. One thing you probably need to do if you are using the Linux Processor SDK provided by TI, is to bypass the I2C EEPROM check in MLO. This is used on TI EVM boards, which have a Board ID EEPROM. If your board does not have an EEPROM you should skip this check, otherwise MLO will stop there.

0 Preetam Reddy over 6 years ago in reply to Biser Gatchev-XID

Intellectual 635 points

I am not using the SDK. I am considering mainline linux.

0 Biser Gatchev-XID over 6 years ago in reply to Preetam Reddy

TI__Guru**** 393215 points

Preetam Reddy said:
I am not using the SDK. I am considering mainline linux.

Sorry, this forum supports only the Linux Processor SDK as provided by TI.

0 Preetam Reddy over 6 years ago in reply to Biser Gatchev-XID

Intellectual 635 points

My .config has

# CONFIG_TI_I2C_BOARD_DETECT is not set

0 Preetam Reddy over 6 years ago in reply to Biser Gatchev-XID

Intellectual 635 points

I will rebuild the changes on SDK and let you know. I am sure I will get the same issue.

0 Brad Griffis over 6 years ago in reply to Preetam Reddy

TI__Guru*** 125430 points

Do you have JTAG available? That's generally the best (perhaps only) path when there's nothing at all on the terminal.

I have some scripts for Code Composer Studio that can help us. The general process for running these scripts is described here:

http://git.ti.com/sitara-dss-files/am335x-dss-files/blobs/master/README

One of the scripts is written specifically to help with these types of boot issues:

http://git.ti.com/sitara-dss-files/am335x-dss-files/blobs/raw/master/am335x-boot.dss

If you can run the script from CCS after a failed boot, and then attach the corresponding txt file, it should give us some clues. It will at least let us know whether it is finding MLO on the eMMC, etc.

Best regards,
Brad

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Linux/AM3358: No boot messages on UART