[U-Boot] [PATCH 1/3] PPC 85xx: Detect e500v2 / e500mc during runtime

[Kumar Gala]

On Jan 23, 2014, at 6:11 AM, Alexander Graf <agraf at suse.de> wrote:

> 
> On 21.01.2014, at 03:25, Scott Wood <scottwood at freescale.com> wrote:
> 
>> On Sun, 2014-01-19 at 16:19 +0100, Alexander Graf wrote:
>>> With the qemu-ppce500 machine type we can run the same board with
>>> either an e500v2 or an e500mc core plugged in.
>>> 
>>> This means that the IVOR setup can't be based on compile time decisions,
>>> so instead we have to do a runtime check which CPU generation we're
>>> running on.
>> 
>> Is this really the only place where you ran into this?
> 
> Yup. At least the only place where the difference actually matters for a VM.
> 
>> Also consider that you'll be adding extra size, and some of our 85xx
>> targets are pretty close to the limit as is (though at least this code
>> isn't used in SPLs).
>> 
>> I guess nobody ever bothered to set IVORs for e6500-specific exceptions.
>> 
>> For that matter, I don't see why we need this code at all.  These aren't
>> the addresses that U-Boot keeps its exception vectors at; it's setting
>> them up for the OS, apparently trying to imitate some other type of
>> book3e chip that has fixed ivors.  Apparently U-Boot has done this only
>> since 2009 (commit 26f4cdba6b51deab4ec99d60be381244068ef950), so it's
>> not even something that an OS could depend on (and certainly Linux
>> doesn't).  So I don't see the point.
> 
> Kumar, do you remember why you put this in? Was it only for prototyping purposes?
> 
> I certainly wouldn't mind removing the whole thing altogether.
> 
> 
> Alex


I feel like we did have some support for timer & external interrupts in u-boot.  Its been a while since I looked.

- k