Problem running Linux 2.6.11 on MPC8272ADS

[Eugene Surovegin]

On Thu, Mar 31, 2005 at 11:03:00AM +0800, Li Yang-r58472 wrote:
> Well, it seems to be a historic problem.  Freescale BSP was 
> originally ported from u-boot-1.0.0 and linux-2.4.22.  So the BCSR 
> was freely chosen as 0xf8000000.  Later, we updated them to 
> u-boot-1.1.1 and linux-2.4.26, and make the BCSR consistent to older 
> version.  However the sourceforge u-boot-1.1.1 support for 
> MPC8272ADS 
> was committed by Arabella guys, they chose BCSR mapping to 
> 0xf4500000.  Kumar's MPC8272 support which is in 2.6.11 source was 
> developed using sourceforge u-boot-1.1.1 seemingly.
> 
> This might brought up a question that if we need a convention or 
> something to define the recommended memory mapping for PowerPC BSPs.  
> As there are different groups of people around the world developing 
> BSPs for PowerPC platforms, and often the communication between them 
> is very limited.
> 
> For now using kernel and u-boot released from the same vendor is recommended.
> 

There is trivial solution which will work regardless on which version 
of U-Boot and kernel you are using.

DO NOT hardcode such stuff in TWO DIFFERENT places, do this only in 
one, in this case it should be firmware (e.g. U-Boot).

In kernel just read BRx register for that chip select and use this 
address for accesses from the kernel. This is how I do on all my 
board ports.

No need to establish any artificial conventions on memory map, etc.

--
Eugene