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
