[U-Boot-Users] U-Boot prompt is not seen on console when U-Boot is in RAM

[Ulf Samuelsson]

Pharaoh . skrev:
> I think I am getting what you are saying...
>
> The u-boot is downloaded to TEXT_BASE = 0x11080000 (from config.mk )
> which is default address for u-boot to load for my board. This is the
> place where u-boot would have relocated itself, had it been copied
> from flash. Infact I was pondering over these:
>
> one of the earlist things u-boot does is initializing the SDRAM
> controller so that RAM can be used for setting up execution
> environment i.e. setting up stack etc. then u-boot relocates itself to
> RAM and so on.
>
You should beware that your code does not reinitialize the SDRAM controller
*after* you have relocated to SDRAM.

For the AT91RM9200 and AT91SAM926x chips booting from serial flash,
the SDRAM is initialized by a small bootloader which also copies U-boot
to SDRAM.
U-Boot never touches the SDRAM controller.

Pls check that your linker file is containing the correct TEXT_BASE.
Sometimes things are done in several places and you have to use the
right one.

> If I have to run u-boot directly from RAM without flashing it i.e. I
> copy u-boot to RAM directly using one of the utilities and make it run
> from there, I am doing something wrong here? In this case when the
> u-boot is copied directly to RAM, has the RAM been initialized? The
> u-boot image gets successfully downloaded to RAM but is the RAM
> initialized in order to execute u-boot directly.
>
>
>
> On 3/9/07, Ulf Samuelsson <ulf at atmel.com> wrote:
>> Pharaoh . skrev:
>> > Hi
>> > I have loaded the u-boot.elf binary to RAM over UART using the OST
>> > utility on Windows XP. I tried to load u-boot.bin to RAM but it is not
>> > working, I think OST is expecting windows binaries when the extension
>> > is .bin. The ELF binary which is compiled on Linux gets for omap730p2
>> > sample board gets successfully downloaded to RAM at the specified
>> > address. I have configured the UART as mentioned in the manual by
>> > using Hyperterminal/Terra Term. After downloading the ELF binary to
>> > RAM, I should
>> > be seeing the U-boot prompt on console. But, just a cursor blinks on
>> > screen. I am sure the  connection is being established but no prompt
>> > is seen.
>> >
>> >
>> > 1. Do I need to burn u-boot.bin and not u-boot.elf? I converted .elf
>> > binary to .raw using OST and it was downloaded successfully to RAM.
>> >
>> > 2. If downloading to RAM is correct then what might have gone wrong
>> ? Why
>> the
>> > u-boot prompt is not visible? What I am
>> missing?CONFIG_SKIP_RELOCATE_UBOOT
>> >
>> > 3. I have taken care that U-Boot doesnt relocate itself to RAM by
>> > setting CONFIG_SKIP_RELOCATE_UBOOT.
>> >
>> > PS: I know I should be using JTAG. What could be the problem with this
>> > console stuff.
>> >
>> > -Pharaoh
>> >
>> >
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>> >
>> Did you link U-Boot to your RAM location, or to 0x0000000 (default).
>> If you link to 0x00000000, then all your strings will probably
>> be in zeroed memory.
>> Been there, done that...
>>
>> -- 
>> Best Regards,
>> Ulf Samuelsson
>>
>>


-- 
Best Regards,
Ulf Samuelsson                ulf at atmel.com
Atmel Nordic AB
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