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| author | Russell King <rmk@dyn-67.arm.linux.org.uk> | 2007-02-06 18:29:53 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2007-02-08 15:49:37 +0100 |
| commit | 7f8e33546d17c7d8849be3a6623c3b6b3c9b588b (patch) | |
| tree | 4ddbbf921dde932f8ce83b519608f945ae43a120 /arch | |
| parent | [ARM] 4133/1: Add ISB after changes to CP15 registers (diff) | |
| download | linux-7f8e33546d17c7d8849be3a6623c3b6b3c9b588b.tar.xz linux-7f8e33546d17c7d8849be3a6623c3b6b3c9b588b.zip | |
[ARM] Don't call consistent_sync() for DMA coherent memory
Memory allocated by the coherent memory allocators will be marked
uncacheable, which means it's pointless calling consistent_sync()
to perform cache maintainence on this memory; it's just a waste of
CPU cycles.
Moreover, with the (subsequent) merge of outer cache support, it
actually breaks things to call consistent_sync() on anything but
direct-mapped memory.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/common/dmabounce.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c index 2e635b814c14..272702accd8b 100644 --- a/arch/arm/common/dmabounce.c +++ b/arch/arm/common/dmabounce.c @@ -281,10 +281,14 @@ map_single(struct device *dev, void *ptr, size_t size, ptr = buf->safe; dma_addr = buf->safe_dma_addr; + } else { + /* + * We don't need to sync the DMA buffer since + * it was allocated via the coherent allocators. + */ + consistent_sync(ptr, size, dir); } - consistent_sync(ptr, size, dir); - return dma_addr; } @@ -397,7 +401,10 @@ sync_single(struct device *dev, dma_addr_t dma_addr, size_t size, default: BUG(); } - consistent_sync(buf->safe, size, dir); + /* + * No need to sync the safe buffer - it was allocated + * via the coherent allocators. + */ } else { consistent_sync(dma_to_virt(dev, dma_addr), size, dir); } |