[U-Boot] [RFC] 0/4] Add Pl330 DMA support

[Dinh Nguyen]

On Sun, Oct 16, 2016 at 10:59 AM, Marek Vasut <marex at denx.de> wrote:
> On 10/15/2016 12:10 AM, Dinh Nguyen wrote:
>>
>>
>> On 10/10/2016 10:52 AM, Dinh Nguyen wrote:
>>> Hi,
>>>
>>> This patchset adds the PL330 DMA driver to U-Boot. The SoCFPGA platform makes
>>> use of the PL330 to transfer zereos to the SDRAM which enables the ECC bit.
>>>
>>> This is only an RFC because after rebasing to v2016.11-rc1, I had to revert
>>> the following patch "a78cd8613204 ARM: Rework and correct barrier definitions"
>>> in order for this patch set to work correctly. With the above patch applied,
>>> after the SDRAM scrubbing is complete, the SPL is failing to find the MMC
>>> device.
>>>
>>
>> I kinda figured out why patch "a78cd8613204 ARM: Rework and correct
>> barrier definitions" is causing SPL to fail after the SDRAM scrub
>> operation. It appears that before the above mentioned patch, the dmb()
>> operation is defined as this:
>>
>> #define dmb()          __asm__ __volatile__ ("" : : : "memory")
>>
>> after the patch, the dmb is now:
>>
>> #define DMB    asm volatile ("dmb sy" : : : "memory")
>>
>> So the "dmb sy" as described in the ARM documentation is a "Full system
>> DMB operation". For whatever reason, this change is causing the SPL
>> error after the SDRAM scrub operation.
>
> Thanks for looking into this, can you poke into it some more ?
>

Of course..

Dinh