[PATCH v2] ARM: tlb: ASID macro should give 32bit result for BE correct operation

[Victor Kamensky]

On 7 October 2013 08:57, Ben Dooks <ben.dooks at codethink.co.uk> wrote:
> On 07/10/13 17:48, Victor Kamensky wrote:
>>
>> Hi Will, Ben, Russell, Thomas,
>>
>> Please review second version of patch that fixes TLB asid issue in big
>> endian
>> V7 image.
>>
>> Changes from v1:
>>     Note previous patch subject line was 'ARM: tlb:
>>     __flush_tlb_mm need to use int asid var for BE correct operation'
>>
>>     Added 'unsigned int' cast into ASID macro itself rather
>>     then use intermediate 'int' variable in __flush_tlb_mm function.
>>     This is done per v1 patch discussion at
>>
>>
>> http://lists.infradead.org/pipermail/linux-arm-kernel/2013-October/202583.html
>>
>> Tested with Linaro BE topic branch on Arndale board. Both LE and BE
>> images were tested.
>
>
> If you are booting on the Arndale board, is there a patch to mark
> the relevant Exynos devices as BE capable?

Arndale need massive fixes in their BSP layer to be endian agnostic
ARM V7 platform. Unfortunate it is not as simple as with few others
that already marked as BE capable.

Please see
https://git.linaro.org/gitweb?p=people/victor.kamensky/linux-linaro-tracking-be.git;a=shortlog;h=refs/heads/llct-be-topic
Mostly it is __raw_xxx conversion to xxx_relaxed, but there are
more subtle changes (some of them similar to changs that you've
done for other platforms). Also there are known unfixed issues like
disabling CONFIG_MMC_DW_IDMAC config because idmac
DMA related code is not endian agnostic yet (btw interesting class
of BE related problem that was not seen before).

In Linaro we use Arndale and Pandaboard as reference platforms
therefore we have BE BSP fixes in our tree. But I am not sure
what is fate of those in long term. Also we consider these as
example of BSP changes that other BSP need to do.

If Exynos and OMAP owners will have any interest for BE images,
and would like to see these changes in main line, we gladly
will work on this. Otherwise changes like this can mess up with
BSP ongoing drivers development.

I think above position is consistent with similar discussion on
some of BE related threads - changing BSP to support BE mode
is BSP owners call.

Thanks,
Victor

> --
> Ben Dooks                               http://www.codethink.co.uk/
> Senior Engineer                         Codethink - Providing Genius