[U-Boot] SoCFPGA PL330 DMA driver and ECC scrubbing

[Jason Rush <jarush@gmail.com>]

Dinh,

A while ago, you posted the following patchset for SoCFPGA to add the PL330
DMA driver, and updated the SoCFPGA SDRAM init to write zeros to SDRAM to
initialize the ECC bits if ECC was enabled:

https://lists.denx.de/pipermail/u-boot/2016-October/269643.html

I know it's been a long time, so I'll summarize some of the conversation...

At the time, you had a problem with the patchset causing the SPL to fail to
find the MMC.  You had tracked it down to an issue with the following commit
"a78cd8613204 ARM: Rework and correct barrier definitions".  You and Marek
discussed it a bit, but I don't think there was a real conclusion.  You
submitted a second version of the patchset asking for advice on debugging
the issue:

https://lists.denx.de/pipermail/u-boot/2016-December/275822.html

No real conversation came from the second patchset, and that was the end of
the patch.

I was hoping we could revisit adding your patchset again. I am working on a
custom SoCFPGA board with a Cyclone V and ECC SDRAM. I rebased your patchset
against v2018.05 and it is working on my custom board (although I don't have
an MMC). I also tested it on a SoCKit booting from an MMC (I forced it to
scrub the SDRAM on the SoCKit, because it doesn't have ECC RAM), and the
SoCKit finds the MMC and boots.

I don't have any suggestions on why it is working now on my board and not
back when you first submitted the patchset.  Maybe something else was fixed
in the MMC? I was hoping you and Marek could test this patch again on some
different SoCFPGA boards to see if you get the same results.

Regards,
Jason