[PATCH] Fix IXP4xx coherent allocations

[David Miller]

From: Krzysztof Halasa <khc at pm.waw.pl>
Date: Sat, 23 Mar 2013 20:35:46 +0100

> ARM core code currently requires coherent DMA mask to be set. Make sure
> we limit PCI devices to 64 MiB while allowing on-chip devices to access
> the whole 4 GiB address space.
> 
> This fixes a v3.7+ regression which broke IXP4xx built-in network devices.
> 
> Signed-off-by: Krzysztof Hałasa <khc at pm.waw.pl>

This requirement is not reasonable.

The DMA API documentation clearly states what the default must be,
and what drivers are guarenteed will be the default.