[PATCH] of: Set the DMA mask to 64 bits on ARM LPAE systems

[Russell King - ARM Linux]

On Thu, Apr 25, 2013 at 10:09:57AM -0700, Laura Abbott wrote:
> I thought about this as well but in arch/arm/mm/mm.h:
>
> #ifdef CONFIG_ZONE_DMA
> extern phys_addr_t arm_dma_limit;
> #else
> #define arm_dma_limit ((phys_addr_t)~0)
> #endif
>
> arm_dma_limit is explicitly cast to phys_addr_t, which means that  
> arm_dma_limit will be always be sizeof(phys_addr_t) regardless of  
> sizeof(dma_addr_t).

This is the size of the DMA zone, which controls the _minimum_ DMA mask
that can be used in the system.  DMA masks must always be greater than
this limit.