[RFC] New target 'cuImage' - compatibility uImage

[Li Yang-r58472]

If my understanding to Matt's idea is correct, it will be a good way,
IMHO.  How about use the naming of uwImage(U-boot Wrapped Image) or
utImage(u-boot device-Tree Image).

-Leo
> -----Original Message-----
> From: linuxppc-dev-bounces+leoli=freescale.com at ozlabs.org
> [mailto:linuxppc-dev-bounces+leoli=freescale.com at ozlabs.org] On Behalf
Of
> Matthew McClintock
> Sent: Thursday, August 03, 2006 4:59 AM
> To: linuxppc-dev
> Subject: [RFC] New target 'cuImage' - compatibility uImage
> 
> Hi all,
> 
> The following is a patch which creates a new target called 'cuImage'.
It
> is designed to correctly package the kernel along with the
> 'arch/powerpc/boot' wrapper code into a uImage to be loaded and
started
> by U-Boot.
> 
> The purpose of this target is to allow boards with older versions of
> U-Boot to utilize the 'bootm' command within U-Boot to run new powerpc
> kernels. The bootwrapper will begin execution and can correctly setup
a
> flat device tree based on values passed in the bd_t structure,
something
> old versions of U-Boot are not capable of.
> 
> One might ask why not just use the 'bootelf' command in u-boot. Well,
> not all boards have that option compiled in, and some other boards
might
> not even have access to the console. Also, the bd_t structure is not
> passed from U-Boot when using the bootelf command so we would have no
> method to correctly fill in values in the device tree. This would
> theoretically allow an old board to start a new kernel without access
to
> the console if required.
> 
> Currently the zImage looks like this:
> 
> ---------------------------------
> - 	_start			-
> -	boot wrapper code	-
> - ----------------------------- -
> - -	device tree	      - -
> - ----------------------------- -
> - ----------------------------- -
> - - 			      - -
> - - 	compressed	      - -
> - - 	kernel image	      - -
> - -			      - -
> - ----------------------------- -
> ---------------------------------
> 
> And the new cuImage will look like this:
> 
> -------------------------------------
> -	compressed uImage	  - -
> - ------------------------------- - -
> - - 	_start			- - -
> - -	boot wrapper code	- - -
> - - ----------------------------- - -
> - - -	device tree	      	- - -
> - - ----------------------------- - -
> - - ----------------------------- - -
> - - - 			      	- - -
> - - - 	UNcompressed	      	- - -
> - - - 	kernel image	      	- - -
> - - -			      	- - -
> - - ----------------------------- - -
> - --------------------------------- -
> -------------------------------------
> 
> -Matthew
>