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

[Marek Vasut]

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 ?

-- 
Best regards,
Marek Vasut