Subject: [PATCH RESEND v2 1/2] ARM: ixp4xx: Make dma_set_coherent_mask common, correct implementation

From: [email-masked] (Arnd Bergmann)
Date: Thu, 20 Mar 2014 12:02:36 +0100

On Thursday 20 March 2014, Krzysztof Ha?asa wrote:
> Simon K?gstr?m <[email-masked]> writes:
> 
> > Thanks. However, Krzysztof thinks that this implementation is
> > incorrect. It certainly fixes my ixp4xx issues, but might not be good
> > for everyone.
> 
> It because you don't have PCI devices setting coherent mask to 32-bits
> (and that's what normal PCI devices do).
> 
> BTW PCI (and other) devices requesting 32-bit coherent allocs don't care
> if they're given 26-bit memory. 26 bits fit perfectly in 32 bits. It's
> the streaming mapping which is (may be) constrained by hardware.

Should I revert the patch then until we have a better fix?

	Arnd