提交 32e8f702 编写于 作者: J James Bottomley 提交者: Linus Torvalds

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: NJames 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
上级 64da82ef
...@@ -24,6 +24,8 @@ enum dma_data_direction { ...@@ -24,6 +24,8 @@ enum dma_data_direction {
#define DMA_28BIT_MASK 0x000000000fffffffULL #define DMA_28BIT_MASK 0x000000000fffffffULL
#define DMA_24BIT_MASK 0x0000000000ffffffULL #define DMA_24BIT_MASK 0x0000000000ffffffULL
#define DMA_MASK_NONE 0x0ULL
static inline int valid_dma_direction(int dma_direction) static inline int valid_dma_direction(int dma_direction)
{ {
return ((dma_direction == DMA_BIDIRECTIONAL) || return ((dma_direction == DMA_BIDIRECTIONAL) ||
...@@ -31,6 +33,11 @@ static inline int valid_dma_direction(int dma_direction) ...@@ -31,6 +33,11 @@ static inline int valid_dma_direction(int dma_direction)
(dma_direction == DMA_FROM_DEVICE)); (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 #ifdef CONFIG_HAS_DMA
#include <asm/dma-mapping.h> #include <asm/dma-mapping.h>
#else #else
......
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