From mboxrd@z Thu Jan  1 00:00:00 1970
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
Date: Tue, 19 May 2015 23:09:36 +0100
Subject: [RFC] arm: DMA-API contiguous cacheable memory
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On Wed, May 20, 2015 at 12:05:54AM +0200, Lorenzo Nava wrote:
> Maybe my interpretation of dma_alloc_coherent() is not correct, and
> the coherency can be managed using the dma_sync_single_for_* functions
> and it doesn't require hardware mechanism.

dma_sync_single_for_* are only for use with the streaming DMA API,
where you must have already mapped the buffer using one of the
dma_map_* functions.  Anything other than that is abusing the API.

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