diff options
| author | Robin Murphy <robin.murphy@arm.com> | 2015-11-06 16:32:51 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-11-06 17:50:42 -0800 |
| commit | 002edb6f6f2a79bea50de11260ddc9572e6db731 (patch) | |
| tree | 045566a75985092e4044a30b5b2363a6e7c92583 /include/linux | |
| parent | 8639b46139b0e4ea3b1ab1c274e410ee327f1d89 (diff) | |
dma-mapping: tidy up dma_parms default handling
Many DMA controllers and other devices set max_segment_size to
indicate their scatter-gather capability, but have no interest in
segment_boundary_mask. However, the existence of a dma_parms structure
precludes the use of any default value, leaving them as zeros (assuming
a properly kzalloc'ed structure). If a well-behaved IOMMU (or SWIOTLB)
then tries to respect this by ensuring a mapped segment does not cross
a zero-byte boundary, hilarity ensues.
Since zero is a nonsensical value for either parameter, treat it as an
indicator for "default", as might be expected. In the process, clean up
a bit by replacing the bare constants with slightly more meaningful
macros and removing the superfluous "else" statements.
[akpm@linux-foundation.org: dma-mapping.h needs sizes.h for SZ_64K]
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Sakari Ailus <sakari.ailus@iki.fi>
Cc: Russell King <rmk+kernel@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/linux')
| -rw-r--r-- | include/linux/dma-mapping.h | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index ac07ff090919..2e551e2d2d03 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -1,6 +1,7 @@ #ifndef _LINUX_DMA_MAPPING_H #define _LINUX_DMA_MAPPING_H +#include <linux/sizes.h> #include <linux/string.h> #include <linux/device.h> #include <linux/err.h> @@ -145,7 +146,9 @@ static inline void arch_teardown_dma_ops(struct device *dev) { } static inline unsigned int dma_get_max_seg_size(struct device *dev) { - return dev->dma_parms ? dev->dma_parms->max_segment_size : 65536; + if (dev->dma_parms && dev->dma_parms->max_segment_size) + return dev->dma_parms->max_segment_size; + return SZ_64K; } static inline unsigned int dma_set_max_seg_size(struct device *dev, @@ -154,14 +157,15 @@ static inline unsigned int dma_set_max_seg_size(struct device *dev, if (dev->dma_parms) { dev->dma_parms->max_segment_size = size; return 0; - } else - return -EIO; + } + return -EIO; } static inline unsigned long dma_get_seg_boundary(struct device *dev) { - return dev->dma_parms ? - dev->dma_parms->segment_boundary_mask : 0xffffffff; + if (dev->dma_parms && dev->dma_parms->segment_boundary_mask) + return dev->dma_parms->segment_boundary_mask; + return DMA_BIT_MASK(32); } static inline int dma_set_seg_boundary(struct device *dev, unsigned long mask) @@ -169,8 +173,8 @@ static inline int dma_set_seg_boundary(struct device *dev, unsigned long mask) if (dev->dma_parms) { dev->dma_parms->segment_boundary_mask = mask; return 0; - } else - return -EIO; + } + return -EIO; } #ifndef dma_max_pfn |