[U-Boot] Seperating MIPS processors

[Daniel Schwierzeck]

Hi,

On 02/12/2011 07:19 AM, Aaron Williams wrote:
> Hi,
>
> One thing that I have had to do in our Octeon port of U-Boot is to seperate
> out the MIPS processors under /arch/mips/cpu much like has been done for ARM
> and PowerPC.

I'd appreciate this separation as it would help me too in supporting new 
Mips-based SoC's.

>
> I have no way of testing the other MIPS platforms, but I've seperated things
> out as follows:
>
> arch/mips/cpu/au1x00
> arch/mips/cpu/incaip
> arch/mips/cpu/mips32
> arch/mips/cpu/octeon
> arch/mips/cpu/purple
>
> All of the code that's common between various 32-bit mips processors I put
> under mips32 with only the processor specific files in the appropriate
> directories.  Is this how I should do it?

Actually all existing CPU's are SoC's based on a Mips4k core. So I
think a better approach that fits into the common u-boot configuration 
scheme is to have a structure like this:

arch/mips/cpu/mips4k/au1x00
arch/mips/cpu/mips4k/incaip
arch/mips/cpu/mips4k/purple
arch/mips/cpu/mips24k/...
arch/mips/cpu/mips34k/...
arch/mips/cpu/mips74k/...
arch/mips/cpu/octeon

The according lines in boards.cfg could be changed from:

dbau1000      mips mips dbau1x00 - - dbau1x00:DBAU1000
incaip_100MHz mips mips incaip   - - incaip:CPU_CLOCK_RATE=100000000
purple        mips mips -        - -

to:

dbau1000      mips mips4k dbau1x00 - au1x00 dbau1x00:...
incaip_100MHz mips mips4k incaip   - incaip incaip:...
purple        mips mips4k -        - purple

>
> Right now I can't really use any of the other MIPS files for our Octeon
> processor. There's just too many differences for this to make sense.
>
> I basically have the following directory structure:
>
...
>
> While it might be quite a while until I can get our stuff into the mainline,
> it would certainly make things easier for me not to have to place our stuff in
> the same directory as the other processors.
>
> -Aaron

I agree. Generally Mips lags behind the other archs in terms of some 
features or config options because of the little support of boards and 
SoC's. Introducing new CPU's like Octeon should give reason to improve 
some parts.

Daniel