use generic DMA mapping code in powerpc V4

Sun Jan 20 00:02:22 AEDT 2019

On Sat, Jan 19, 2019 at 12:52:52PM +0100, Christian Zigotzky wrote:
> Hi Christoph,
>
> I have found a small workaround. If I add 'mem=3500M' to the boot arguments 
> then it detects the SATA hard disk and boots without any problems.
>
> X5000> setenv bootargs root=/dev/sda2 console=ttyS0,115200 mem=3500M

Interesting.  This suggest it is related to the use of ZONE_DMA by
the FSL SOCs that your board uses.  Let me investigate this a bit more.