[PATCH 06/10] soc/qbman: Add ARM equivalent for flush_dcache_range()

[Roy Pledge]

On 2/6/2017 5:37 PM, Russell King - ARM Linux wrote:
> On Mon, Feb 06, 2017 at 10:26:26PM +0000, Roy Pledge wrote:
>> Why don't I simplify this and use dma_sync_single_for_device() to flush
>> the cache?
> ... which can only be used on direct-mapped memory.
>
Then I don't see another (or understand) any other option. There is no
way I can add a large area of physical memory carved out by
of_reserve_mem to a DMA allocator since both ioremap and memremap throw
an error if I try to do so. I appreciate the suggestions from people to
resolve this but so far there isn't a workable solution to the problem.
As far as I can tell other users of dma_declare_coherent_memory() are
using it for device backed memory, not DDR.  It sounds like a solution
on the surface but when you dig into the details it just doesn't work. 
Please let me know if I'm missing something, I really want to close this
issue so we can get upstream support for this device on ARM.


Roy