Good point. There is also IMMR need to be passed from bootloader to kernel. We can make more use of the u-boot bd_info mechanism. But it binds ppc linux to u-boot boot loader. I don't know if we should make it a porting convention.
Best Regards, Leo > -----Original Message----- > From: Eugene Surovegin [mailto:ebs at ebshome.net] > Sent: Thursday, March 31, 2005 11:27 AM > To: Li Yang-r58472 > Cc: Walter L. Wimer III; Gala Kumar K.-galak; Linux PPC Embedded list > Subject: Re: Problem running Linux 2.6.11 on MPC8272ADS > > 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