Re: [PATCH v3 00/10] enhance mmc

[Ryan Harkin <ryan.harkin@linaro.org>]

On 11 October 2016 at 17:28, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> On 11 October 2016 at 17:27, Ryan Harkin <ryan.harkin@linaro.org> wrote:
>> On 11 October 2016 at 17:24, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>>> Hi Ryan,
>>>
>>> On 11 October 2016 at 17:22, Ryan Harkin <ryan.harkin@linaro.org> wrote:
>>> [...]
>>>> And OpenPlatformPkg was taken from my repo, which only carries one
>>>> patch essential for TC2 booting:
>>>>   c22a665  2016-01-29  HACK: Platforms/ARM: TC2: set
>>>> gArmTokenSpaceGuid.PcdNormalMemoryNonshareableOverride TRUE  [Ryan
>>>> Harkin]
>>>
>>> Shouldn't we simply merge that patch?
>>
>> I think Leif said no, back when TC2 broken in mainline.
>>
>> The commit that broke it was 0c9a522f28772049ae37c85b8ae589a98d2d3b81
>> "ArmPkg/ArmLib: mark all cached mappings as (inner) shareable".  IIRC
>> Leif said there is something wrong with the TC2 setup code meaning
>> that we need to set the PCD, even though we shouldn't need to.
>>
>> And I've never had time to work it out, so I've just carried the patch.
>
> Ah right, I remember now.

And if I'd looked further down my HACK commit, I'd have seen this text
explaining what happened:

   However, the topic was discussed on the mailing list:

      https://www.mail-archive.com/edk2-devel@lists.01.org/msg03974.html

    The correct solution for platforms that wish to revert this behaviour
    is to set the following PCD to TRUE:

      gArmTokenSpaceGuid.PcdNormalMemoryNonshareableOverride

    However, for TC2 should not need to do this.  Work continues to
    ascertain why TC2 breaks with shareable mappings.  Current thinking is
    that CCI-400 needs configuring before shareable mappings will work.

:-)