From d911202e3f722c29065942400ea108b7096bdac7 Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Tue, 26 Oct 2010 14:22:18 -0700 Subject: [PATCH] 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 Cc: Miklos Szeredi Cc: Jeff Dike Cc: Sam Ravnborg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/Kconfig.um | 3 + arch/um/defconfig | 1 - arch/um/include/asm/dma-mapping.h | 112 -------------------------------------- 3 files changed, 3 insertions(+), 113 deletions(-) delete mode 100644 arch/um/include/asm/dma-mapping.h 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 - -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 -- 2.7.4