Informations about mem and proc environment between bootloader and kernel

[raul.moreno at telvent.abengoa.com]

Hello Fabien,

you should download the U-boot sources from sourceforge.net. There is a
README file there where you can read about porting U-boot.
The porting to a custom board of U-boot is easier when your cpu is include,
like in your case (mpc8xx). Basically you have to create a new entry in
board directory. There you have to insert the initialization code for your
flash, sdram and other devices. You also have to make a file as the ones in
/include/configs/ with your configuration board.

It is essential to have correct environment variables when Linux takes the
control.
If you use the u-boot command "bootm" in order to boot Linux, the file
where U-Boot transfer the control to Linux is /common/cmd_bootm.c.

Moreover I would recommend you a book which explains many things regarding
porting Linux (and U-boot):
Embedded Linux Primer: A practical, real-world  approach.

Cheers,

Raúl Moreno



Raúl Moreno Beltrán
Telvent Energía, S. A.
División de Tecnología. Desarrollo Software
Tlfo: 954935670



"fabien boucher" <fabien.fb at gmail.com>
"fabien boucher"
Enviado por:
linuxppc-embedded-bounces+raul.moreno=telvent.abengoa.com at ozlabs.org
13/09/2007 16:05
                                                                                                                       
 Para:   linuxppc-embedded at ozlabs.org                                                                                  
                                                                                                                       
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 Asunto: Informations about mem and proc environment between bootloader and     kernel                                 
                                                                                                                       





And I need some help for my project (I'm in internship) to port linux on a
custom board.
This board has been developped by the company where i'm doing the intership
and it's
based on a MPC875 with RAM and Flash chips and several other devices.
Currently the board run with a BSP developped
by the company's developpers, the BSP launch Psos.
This BSP is able to decompress an image and load it in RAM.
I plan to use U-boot to be more able to boot a kernel but as it's not a
common
board so it's not initialy supported by U-boot. So I have two choices first
use the BSP with some changes to adapt it for loading the Linux kernel or
using U-boot.
I'm looking for informations about the memory and processor environment
needed by linux to
boot properly for evaluate whether the use of a customize BSP is the
easiest way against
the port of a new board under U-boot. So if someone know where i can found
those informations
concerning the step between where the boot program have control of the cpu
and where Linux
take control.

Thank you,
Fabien
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