Uart boot on custom Sitara board based on the AM3352 EVM

Preetam Reddy

I have a custom board that is hard wired to boot from uart failing which it will boot from nand. As the board is blank, It needs to boot from uart.

I downloaded the linux sdk and built the spl.

I use the uart to transfer the spl u-boot.bin to the board.

However I do not get a serial "CCCC" to transfer the actual u-boot.img after it loads u-boot-spl.bin

The following is the serial output:

CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
U-Boot SPL 2014.07-00107-ga6ef75a (May 08 2015 - 17:36:16)

How do I fix this? Do I need to rebuild the spl with a different config? What config options do I need to change for it to boot from uart.

Update: I was able to write a custome board file and bring it to a point where the u-boot-spl.bin loads over uart. However, there seems to be an issue with with the ddr initialization. The spl tries a memset of 16MB on the ddr to make space for the u-boot.img. I get a crash here usually. However, sometimes when I use ccs with jtag, this works (sometimes only) and goes ahead to ymodem initialization. I am doing a board bring up all alone..

Update 2: I am now able to get u-boot up and running and have a u-boot console. I need the commands to load the uImage and dtbs and boot from uart. I also need commands to copy the MLO and u-boot to the emmc from uart. The emmc is still blank.

over 10 years ago

0 Yordan Kovachev over 10 years ago

TI__Guru**** 161600 points

Hi,

The steps you need to take in order to boot from uart are described here: processors.wiki.ti.com/.../AM335x_U-Boot_User%27s_Guide

It seems that your u-boot-spl.bin is not executing successfully. Could you please describe how you build your u-boot-spl.bin ?

Best Regards,
Yordan

0 Preetam Reddy over 10 years ago in reply to Yordan Kovachev

Intellectual 635 points

Hi,

I have downloaded the ti-processor-sdk-linux-am335x-evm-01.00.00.00-Linux-x86-Install.bin from "http://software-dl.ti.com/sitara_linux/esd/processor-sdk/PROCESSOR-SDK-LINUX-AM335X/latest/index_FDS.html"

Regards,

Preetam

0 Preetam Reddy over 10 years ago in reply to Yordan Kovachev

Intellectual 635 points

Hi,

I pulled in software-dl.ti.com/.../index_FDS.html
1. Downloaded Linux SDK using the bin
2. Executed setup.sh
3. Executed make all
4. Pulled in the u-boot-spl.bin and u-boot.bin from board-support/u-boot-2014.07-g7e537bf/spl

Regards,
Preetam

0 Yordan Kovachev over 10 years ago in reply to Preetam Reddy

TI__Guru**** 161600 points

Hi Preetam,

Sorry for the delayed response.

Are you able to boot your board through sd-card?

Can you try building it as:

1. export ARCH=arm
2. export PATH=$PATH:<path_to_ti-processor-sdk-linux-am335x-evm-01.00.00.00>/linux-devkit/sysroots/i686-arago-linux/usr/bin/
3. export CROSS_COMPILE=arm-linux-gnueabihf-
4. cd <path_to_ti-processor-sdk-linux-am335x-evm-01.00.00.00>/board-support/u-boot-2014.07-g7e537bf/
5. make distclean
6. make am335x_evm_config
7. make -j4
And try booting through uart?

Try enabling all debug messages in bootloader, this could give you some pointers on where to start your debugging.

Best Regards,
Yordan

0 Preetam Reddy over 10 years ago in reply to Yordan Kovachev

Intellectual 635 points

I tried this. Even here the u-boot-spl.bin is not accepted by the device. Its a production board based on am335x evm. there are no sd card slots. My only option is to use the uart. As a matter of fact, I cant even change the boot mode as the switch settings are hardwired on pcb. there is no boot selector switch. Another thing I have noticed is that somewhere along the line, UART boot has been completely left out. I got a few images of SDK 7 which are accepted but I am unable get its source. It doesn't install on my VM.

0 Yordan Kovachev over 10 years ago in reply to Preetam Reddy

TI__Guru**** 161600 points

Preetam,

Preetam Reddy said:
Another thing I have noticed is that somewhere along the line, UART boot has been completely left out. I got a few images of SDK 7 which are accepted but I am unable get its source. It doesn't install on my VM

Do you mean that the u-boot-spl.bin generated after the build of SDK8.0 is not accepted? Or the u-boot.img is not compatible with your board?

Have you tried building and using the mainline u-boot: http://git.denx.de/?p=u-boot.git;a=summary ?

Use the same steps for building the sources:

host$ make distclean

host$ make am335x_evm_defconfig

host$ make -j4

Best Regards,

Yordan

0 Preetam Reddy over 10 years ago in reply to Yordan Kovachev

Intellectual 635 points

I meant that the spl file wouldnt load. I managed to get around that and have spl loaded. I made a board config specific to my board based on the am335x_evm files.

However it no longer asks me for the u-boot image over serial.

=========================Console log===================

set mux invoked

Pin Mux config

calling sdram init

sdram init

sdram exit

s_init exiting

====================================================

0 Yordan Kovachev over 10 years ago in reply to Preetam Reddy

TI__Guru**** 161600 points

Can you share the config file?
Also could you enable all debug prints in your bootloader? Maybe there is some warning/debug message/ stating why your spl would not search for u-boot.img.

Best Regards,
Yordan

0 Preetam Reddy over 10 years ago in reply to Yordan Kovachev

Intellectual 635 points

Hi Yordon,

I was able to get to the y-modem today. It turns out to be the pll lockon delays. This delay is mostly coming in for the beagle and evm boards from the many i2c reads of the eeprom. I had to identify and put a delay to get the ddr memory up and running but still there is now issue with y-modem. The y-modem is too slow and crashes with a FIQ after a minute or 2.

I have attached the config files:

boards.cfg

am335x_neato.h

ti_am335x_neato_base.h

0 Yordan Kovachev over 10 years ago in reply to Preetam Reddy

TI__Guru**** 161600 points

Hi Preetam,

Thanks for sharing your solution with the community.

Best Regards,
Yordan

0 Preetam Reddy over 10 years ago in reply to Yordan Kovachev

Intellectual 635 points

I need help for 2 things:

1. How to disable the NAND and NOR support in U-boot.

2. How to make it go to console by default

0 Preetam Reddy over 10 years ago in reply to Preetam Reddy

Intellectual 635 points

Where is CONFIG_NAND in TI's config ?

0 Steve Kipisz over 10 years ago in reply to Preetam Reddy

TI__Genius 15510 points

It is in boards.cfg. If you look at the entry in there for am335x_evm, you'll find a line that has

am335x_evm:SERIAL1,CONS_INDEX=1,NAND

Just remove the NAND and CONFIG_NAND will not be defined.

Steve K.

0 Preetam Reddy over 10 years ago in reply to Steve Kipisz

Intellectual 635 points

As explained before, I am working on a custom board and it does not have NAND, NOR, SD card.
It has uart port which is required for first boot and I need put in images from there into the emmc which will boot subsequently. How do I configure the build to give me the right environment and u-boot console.
Right now it says:

MMC: OMAP SD/MMC: 0, OMAP SD/MMC: 1

Net: <thaddr> not set. Validating first E-fuse MAC
Phy not found
cpsw, usb_ether

I need to get a u-boot console instead of it trying to boot off usb and ethernet. The board does not have an ethernet port. It has the usb which its trying to use as ethernet.

0 Preetam Reddy over 10 years ago in reply to Preetam Reddy

Intellectual 635 points

I had to remove the network and USB configuration from the board as I did not have support for booting over them. Now I have a u-boot comand line. Now I am wondering how to load them to emmc and also how to load the linux kernel.

0 Preetam Reddy over 10 years ago in reply to Steve Kipisz

Intellectual 635 points

Thank you for that. I am trying to format my blank emmc and write gpt to it. I try the following and it doesnt work:
U-Boot# setenv uuid_gpt_disk 30ad58ca-201c-4d38-83b1-61c92772e718
U-Boot# setenv uuid_gpt_boot 21d47ea2-de79-419b-8b2c-e2ba0ed37493
U-Boot# setenv partitions "uuid_disk=${uuid_gpt_disk};name=boot,Size=100MiB,uuid=${uuid_gpt_boot}"
U-Boot# gpt write mmc 0 ${partitions}
Writing GPT: Partition list incomplete
error!

What is the correct command? Should I even use the gpt numbers with or without '-' ?

0 Preetam Reddy over 10 years ago in reply to Preetam Reddy

Intellectual 635 points

I needed to add a ';' at the end.

0 Preetam Reddy over 10 years ago in reply to Yordan Kovachev

Intellectual 635 points

Can you help me with loading the MLO, u-boot.img, uImage and dtb from uart to emmc while you are in u-boot.
How do I do this and what are teh commands and load addresses. How do I install a filesystem on to the emmc from u-boot.

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Uart boot on custom Sitara board based on the AM3352 EVM