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authorJames Bottomley <James.Bottomley@SteelEye.com>2007-10-16 01:23:55 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-16 09:42:50 -0700
commit32e8f70230c0c417490787b3f48b6ed6c48e7ec9 (patch)
tree54ef9f6c8960ab2a9634d0d82d69d6049bc6f3fb /include
parent64da82efae0d7b5f7c478021840fd329f76d965d (diff)
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introduce DMA_MASK_NONE as a signal for unable to do DMA
Some devices are incapable of DMA and need to be recognised as such. Introduce a NONE dma mask to facilitate this plus an inline function: is_device_dma_capable() to check this. Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Tejun Heo <htejun@gmail.com> Cc: Natalie Protasevich <protasnb@gmail.com> Cc: Jeff Garzik <jgarzik@pobox.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/dma-mapping.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 2dc21cbeb30..0ebfafbd338 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -24,6 +24,8 @@ enum dma_data_direction {
#define DMA_28BIT_MASK 0x000000000fffffffULL
#define DMA_24BIT_MASK 0x0000000000ffffffULL
+#define DMA_MASK_NONE 0x0ULL
+
static inline int valid_dma_direction(int dma_direction)
{
return ((dma_direction == DMA_BIDIRECTIONAL) ||
@@ -31,6 +33,11 @@ static inline int valid_dma_direction(int dma_direction)
(dma_direction == DMA_FROM_DEVICE));
}
+static inline int is_device_dma_capable(struct device *dev)
+{
+ return dev->dma_mask != NULL && *dev->dma_mask != DMA_MASK_NONE;
+}
+
#ifdef CONFIG_HAS_DMA
#include <asm/dma-mapping.h>
#else