[okl4-developer] S3C2440A and okl4

[Geoffrey Lee]

On Mon, Aug 18, 2008 at 03:07:20PM +0000, Rémy Gottschalk wrote:
> Geoffrey Lee a écrit :
>> On Mon, Aug 18, 2008 at 02:33:49PM +0000, Rémy Gottschalk wrote:
>>> The faulty instruction seems to be  a clzeq within arm_comon_return :
>>
>> Hi Remy
>>
>> I don't think the clz instruction is supported on the arm920t, which 
>> might be the cause of the problem.
>>
>

Hi Remy

> I am no arm guru but doing some research it appears the same to me.  
> Digging a little further i discovered that this portion of code come  
> from arch/arm/pistachio/v5/src/traps.spp
>
> I also found that v.2.1 doesn't contain any clz instruction. So for a  
> quick test I copied this file from the v 2.1 to the current version  
> (2.1.1-patch.9). And well I got a nice amount of test to pass. :)
>
> Of course I know this solution may have unfortunate side effects.
>
> Also does this means support for gta01 arch is currently broken ?
>

We run tests on the gta01 simulator platform regularly for testing,
in theory should boot on hardware.  The simulator sometimes does
in rare cases fail to pick up issues such as the one you have encountered.
Addressing this specific issue however should be easy (see below)

> And would a proper solution be to have some arch/arm/pistachio/v4  
> directory ?

My understanding is that the v4 and v5 are very similar, hence the code 
should run on both.  The solution in this case is to ensure that
when running on v4 the code uses instructions that is functionally
equivalent to the current implemention but without v5-only
instructions.

>
>
> Anyway thank you (as always).
>
> Regards,
>

	-gl