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