linux-kernel - [PATCH 1/3] hexagon: remove the sync_single_for

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Message-Id: <20180719125635.824-2-hch@lst.de>
Date:   Thu, 19 Jul 2018 05:56:33 -0700
From:   Christoph Hellwig <hch@....de>
To:     Richard Kuo <rkuo@...eaurora.org>
Cc:     linux-hexagon@...r.kernel.org, iommu@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 1/3] hexagon: remove the sync_single_for_cpu DMA operation

hexagon does all the required cache maintainance at dma map time, and none
at unmap time.  It thus has to implement sync_single_for_device to match
the map cace for buffer reuse, but there is no point in doing another
invalidation in the sync_single_cpu_case, which in terms of cache
maintainance is equivalent to the unmap case.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 arch/hexagon/kernel/dma.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/arch/hexagon/kernel/dma.c b/arch/hexagon/kernel/dma.c
index 77459df34e2e..d2b717f352f4 100644
--- a/arch/hexagon/kernel/dma.c
+++ b/arch/hexagon/kernel/dma.c
@@ -181,13 +181,6 @@ static dma_addr_t hexagon_map_page(struct device *dev, struct page *page,
 	return bus;
 }
 
-static void hexagon_sync_single_for_cpu(struct device *dev,
-					dma_addr_t dma_handle, size_t size,
-					enum dma_data_direction dir)
-{
-	dma_sync(dma_addr_to_virt(dma_handle), size, dir);
-}
-
 static void hexagon_sync_single_for_device(struct device *dev,
 					dma_addr_t dma_handle, size_t size,
 					enum dma_data_direction dir)
@@ -205,7 +198,6 @@ const struct dma_map_ops hexagon_dma_ops = {
 	.free		= hexagon_free_coherent,
 	.map_sg		= hexagon_map_sg,
 	.map_page	= hexagon_map_page,
-	.sync_single_for_cpu = hexagon_sync_single_for_cpu,
 	.sync_single_for_device = hexagon_sync_single_for_device,
 	.mapping_error	= hexagon_mapping_error,
 };
-- 
2.18.0