From: Shannon Nelson <redacted>
Date: Mon,  6 Jan 2020 13:05:10 -0800

The IBM Power9 ppc64 seems to have a problem with not wanting
to limit the address space used by a PCI device.  The Naples
internal HW can only address up to 52 bits, but the ppc does
not play well with that limitation.  This patch tells the
system how to work with Naples successfully.

Signed-off-by: Shannon Nelson <redacted>

Then dma_set_mask_and_coherent() should fail, either that or the mask
being passed in isn't correct.

There is no reason this hack should be necessary in any driver.

Our DMA abstractions are built to handle exactly this kind of
situation.

Please find out what is really going on and fix this properly.

Thank you.