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authorRussell King <rmk@dyn-67.arm.linux.org.uk>2007-02-06 17:29:53 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2007-02-08 14:49:37 +0000
commit7f8e33546d17c7d8849be3a6623c3b6b3c9b588b (patch)
tree4ddbbf921dde932f8ce83b519608f945ae43a120 /arch/arm/common
parent56660faf9e8088542e85207df45fb9c5f4dd3909 (diff)
[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/arm/common')
-rw-r--r--arch/arm/common/dmabounce.c13
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);
}