* [patch 022/114] arch/openrisc: add option to skip DMA sync as a part of mapping
@ 2016-12-14 23:05 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2016-12-14 23:05 UTC (permalink / raw)
To: torvalds, mm-commits, akpm, alexander.h.duyck, jonas
From: Alexander Duyck <alexander.h.duyck@intel.com>
Subject: arch/openrisc: add option to skip DMA sync as a part of mapping
This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
via a sync_for_cpu or sync_for_device call.
Link: http://lkml.kernel.org/r/20161110113524.76501.87966.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
arch/openrisc/kernel/dma.c | 3 +++
1 file changed, 3 insertions(+)
diff -puN arch/openrisc/kernel/dma.c~arch-openrisc-add-option-to-skip-dma-sync-as-a-part-of-mapping arch/openrisc/kernel/dma.c
--- a/arch/openrisc/kernel/dma.c~arch-openrisc-add-option-to-skip-dma-sync-as-a-part-of-mapping
+++ a/arch/openrisc/kernel/dma.c
@@ -141,6 +141,9 @@ or1k_map_page(struct device *dev, struct
unsigned long cl;
dma_addr_t addr = page_to_phys(page) + offset;
+ if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+ return addr;
+
switch (dir) {
case DMA_TO_DEVICE:
/* Flush the dcache for the requested range */
_
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2016-12-14 23:05 [patch 022/114] arch/openrisc: add option to skip DMA sync as a part of mapping akpm
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