[U-Boot] Kernel loading and memory layout

[Vinay Venkataraghavan]

Thank you all for your responses. Has definitely got me going. Another really quick question. I notice that there are a lot of debug switches in the uboot code.

How do I turn on debugs in uboot. Is there a compile time flag or is there and #define that needs to be turned on. I looked in the code and could not find how all the debugs are related and can be switched on?

Thank you.
Regards,
Vinay



----- Original Message ----
From: Wolfgang Denk <wd at denx.de>
To: Jerry Van Baren <gerald.vanbaren at ge.com>
Cc: Vinay Venkataraghavan <raghavanvinay at yahoo.com>; u-boot at lists.denx.de
Sent: Wednesday, January 21, 2009 11:03:39 AM
Subject: Re: [U-Boot] Kernel loading and memory layout

Dear Jerry Van Baren,

In message <49771642.1050705 at ge.com> you wrote:
>
> U-Boot loads the linux kernel in RAM where ever you tell it to and then 
> jumps to the linux kernel entry point.  The linux kernel, on start up, 
> relocates itself to where *it* wants to live and then proceeds.

This is not correct. You load the kernel to some memory  address  (in
RAM  or  flash or SRAM etc.). U-Boot will then copy (or "load") it to
the address givenm in the "load address" parameter of the image file,
and then jumpt to the entry point address given in the  "entry  point
address" parameter of the image file. Normally (at leats on PowerPC),
Linux  will NOT relocate itself (it may set up the MMU later, but the
initial execution starts exactly at the "entry point address").


Best regards,

Wolfgang Denk

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