diff options
author | FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> | 2010-10-26 21:22:18 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-26 23:52:12 (GMT) |
commit | d911202e3f722c29065942400ea108b7096bdac7 (patch) | |
tree | 17c0a4c8d2fa36db4469ddb21e7edee29184df74 /arch/um | |
parent | 98c532ecbe582586e204688c6cde7e27580cc43f (diff) | |
download | linux-d911202e3f722c29065942400ea108b7096bdac7.tar.xz |
uml: define CONFIG_NO_DMA
I think that it's better to detect DMA misuse at build time rather than
calling BUG_ON. Architectures that can't do DMA need to define
CONFIG_NO_DMA.
Thanks to Sam Ravnborg for explaining how CONFIG_NO_DMA and CONFIG_HAS_DMA
work:
http://marc.info/?l=linux-kernel&m=128359913825550&w=2
HAS_DMA is defined like this:
config HAS_DMA
boolean
depends on !NO_DMA
default y
So to set HAS_DMA to true an arch should do:
1) Do not define NO_DMA
2) Define NO_DMA abd set it to 'n'
Must archs - including um - used principle 1).
In the um case we want to say that we do NOT have any DMA.
This can be done in two ways.
a) define NO_DMA and set it to 'y'
b) redefine HAS_DMA and set it to 'n'.
The patch you provided used principle b) where other archs use principle a).
So I suggest you should use principle a) for um too.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/um')
-rw-r--r-- | arch/um/Kconfig.um | 3 | ||||
-rw-r--r-- | arch/um/defconfig | 1 | ||||
-rw-r--r-- | arch/um/include/asm/dma-mapping.h | 112 |
3 files changed, 3 insertions, 113 deletions
diff --git a/arch/um/Kconfig.um b/arch/um/Kconfig.um index ec2b8da..ffe0934 100644 --- a/arch/um/Kconfig.um +++ b/arch/um/Kconfig.um @@ -147,3 +147,6 @@ config KERNEL_STACK_ORDER This option determines the size of UML kernel stacks. They will be 1 << order pages. The default is OK unless you're running Valgrind on UML, in which case, set this to 3. + +config NO_DMA + def_bool y diff --git a/arch/um/defconfig b/arch/um/defconfig index 6bd456f..564f3de 100644 --- a/arch/um/defconfig +++ b/arch/um/defconfig @@ -566,7 +566,6 @@ CONFIG_CRC32=m # CONFIG_CRC7 is not set # CONFIG_LIBCRC32C is not set CONFIG_PLIST=y -CONFIG_HAS_DMA=y # # SCSI device support diff --git a/arch/um/include/asm/dma-mapping.h b/arch/um/include/asm/dma-mapping.h deleted file mode 100644 index 1f469e80..0000000 --- a/arch/um/include/asm/dma-mapping.h +++ /dev/null @@ -1,112 +0,0 @@ -#ifndef _ASM_DMA_MAPPING_H -#define _ASM_DMA_MAPPING_H - -#include <asm/scatterlist.h> - -static inline int -dma_supported(struct device *dev, u64 mask) -{ - BUG(); - return(0); -} - -static inline int -dma_set_mask(struct device *dev, u64 dma_mask) -{ - BUG(); - return(0); -} - -static inline void * -dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle, - gfp_t flag) -{ - BUG(); - return((void *) 0); -} - -static inline void -dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, - dma_addr_t dma_handle) -{ - BUG(); -} - -static inline dma_addr_t -dma_map_single(struct device *dev, void *cpu_addr, size_t size, - enum dma_data_direction direction) -{ - BUG(); - return(0); -} - -static inline void -dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size, - enum dma_data_direction direction) -{ - BUG(); -} - -static inline dma_addr_t -dma_map_page(struct device *dev, struct page *page, - unsigned long offset, size_t size, - enum dma_data_direction direction) -{ - BUG(); - return(0); -} - -static inline void -dma_unmap_page(struct device *dev, dma_addr_t dma_address, size_t size, - enum dma_data_direction direction) -{ - BUG(); -} - -static inline int -dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, - enum dma_data_direction direction) -{ - BUG(); - return(0); -} - -static inline void -dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nhwentries, - enum dma_data_direction direction) -{ - BUG(); -} - -static inline void -dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle, size_t size, - enum dma_data_direction direction) -{ - BUG(); -} - -static inline void -dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nelems, - enum dma_data_direction direction) -{ - BUG(); -} - -#define dma_alloc_noncoherent(d, s, h, f) dma_alloc_coherent(d, s, h, f) -#define dma_free_noncoherent(d, s, v, h) dma_free_coherent(d, s, v, h) - -static inline void -dma_cache_sync(struct device *dev, void *vaddr, size_t size, - enum dma_data_direction direction) -{ - BUG(); -} - -static inline int -dma_mapping_error(struct device *dev, dma_addr_t dma_handle) -{ - BUG(); - return 0; -} - -#endif |