[PATCH v2 19/29] dma: allocate 32-byte aligned buffers by default

[Ahmad Fatoum]

If dma_alloc() is really used for streaming-dma between cache-incoherent
masters, it should return cache-line aligned buffers, so we don't risk
invalidating shared cache lines. Bump up the default alignment to 32-bytes.

This doesn't affect ARM, as it defines its own implementation with
64-byte buffers.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 include/dma.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/dma.h b/include/dma.h
index 1b1cb3a40796..90f9254ea80f 100644
--- a/include/dma.h
+++ b/include/dma.h
@@ -8,6 +8,7 @@
 
 #include <malloc.h>
 #include <xfuncs.h>
+#include <linux/kernel.h>
 
 #include <dma-dir.h>
 #include <asm/dma.h>
@@ -15,10 +16,14 @@
 
 #define DMA_ADDRESS_BROKEN	NULL
 
+#ifndef DMA_ALIGNMENT
+#define DMA_ALIGNMENT	32
+#endif
+
 #ifndef dma_alloc
 static inline void *dma_alloc(size_t size)
 {
-	return xmalloc(size);
+	return xmemalign(DMA_ALIGNMENT, ALIGN(size, DMA_ALIGNMENT));
 }
 #endif
 
-- 
2.29.2