diff options
Diffstat (limited to 'arch/arm/include/asm/dma-mapping.h')
| -rw-r--r-- | arch/arm/include/asm/dma-mapping.h | 64 |
1 files changed, 47 insertions, 17 deletions
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h index a96300bf83f..e850f5c1607 100644 --- a/arch/arm/include/asm/dma-mapping.h +++ b/arch/arm/include/asm/dma-mapping.h @@ -57,20 +57,49 @@ static inline dma_addr_t virt_to_dma(struct device *dev, void *addr) #endif /* - * DMA-consistent mapping functions. These allocate/free a region of - * uncached, unwrite-buffered mapped memory space for use with DMA - * devices. This is the "generic" version. The PCI specific version - * is in pci.h - * - * Note: Drivers should NOT use this function directly, as it will break - * platforms with CONFIG_DMABOUNCE. - * Use the driver DMA support - see dma-mapping.h (dma_sync_*) + * Private support functions: these are not part of the API and are + * liable to change. Drivers must not use these. */ extern void dma_cache_maint(const void *kaddr, size_t size, int rw); extern void dma_cache_maint_page(struct page *page, unsigned long offset, size_t size, int rw); /* + * The DMA API is built upon the notion of "buffer ownership". A buffer + * is either exclusively owned by the CPU (and therefore may be accessed + * by it) or exclusively owned by the DMA device. These helper functions + * represent the transitions between these two ownership states. + * + * As above, these are private support functions and not part of the API. + * Drivers must not use these. + */ +static inline void __dma_single_cpu_to_dev(const void *kaddr, size_t size, + enum dma_data_direction dir) +{ + if (!arch_is_coherent()) + dma_cache_maint(kaddr, size, dir); +} + +static inline void __dma_single_dev_to_cpu(const void *kaddr, size_t size, + enum dma_data_direction dir) +{ + /* nothing to do */ +} + +static inline void __dma_page_cpu_to_dev(struct page *page, unsigned long off, + size_t size, enum dma_data_direction dir) +{ + if (!arch_is_coherent()) + dma_cache_maint_page(page, off, size, dir); +} + +static inline void __dma_page_dev_to_cpu(struct page *page, unsigned long off, + size_t size, enum dma_data_direction dir) +{ + /* nothing to do */ +} + +/* * Return whether the given device DMA address mask can be supported * properly. For example, if your device can only drive the low 24-bits * during bus mastering, then you would pass 0x00ffffff as the mask @@ -304,8 +333,7 @@ static inline dma_addr_t dma_map_single(struct device *dev, void *cpu_addr, { BUG_ON(!valid_dma_direction(dir)); - if (!arch_is_coherent()) - dma_cache_maint(cpu_addr, size, dir); + __dma_single_cpu_to_dev(cpu_addr, size, dir); return virt_to_dma(dev, cpu_addr); } @@ -329,8 +357,7 @@ static inline dma_addr_t dma_map_page(struct device *dev, struct page *page, { BUG_ON(!valid_dma_direction(dir)); - if (!arch_is_coherent()) - dma_cache_maint_page(page, offset, size, dir); + __dma_page_cpu_to_dev(page, offset, size, dir); return page_to_dma(dev, page) + offset; } @@ -352,7 +379,7 @@ static inline dma_addr_t dma_map_page(struct device *dev, struct page *page, static inline void dma_unmap_single(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { - /* nothing to do */ + __dma_single_dev_to_cpu(dma_to_virt(dev, handle), size, dir); } /** @@ -372,7 +399,8 @@ static inline void dma_unmap_single(struct device *dev, dma_addr_t handle, static inline void dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { - /* nothing to do */ + __dma_page_dev_to_cpu(dma_to_page(dev, handle), handle & ~PAGE_MASK, + size, dir); } #endif /* CONFIG_DMABOUNCE */ @@ -400,7 +428,10 @@ static inline void dma_sync_single_range_for_cpu(struct device *dev, { BUG_ON(!valid_dma_direction(dir)); - dmabounce_sync_for_cpu(dev, handle, offset, size, dir); + if (!dmabounce_sync_for_cpu(dev, handle, offset, size, dir)) + return; + + __dma_single_dev_to_cpu(dma_to_virt(dev, handle) + offset, size, dir); } static inline void dma_sync_single_range_for_device(struct device *dev, @@ -412,8 +443,7 @@ static inline void dma_sync_single_range_for_device(struct device *dev, if (!dmabounce_sync_for_device(dev, handle, offset, size, dir)) return; - if (!arch_is_coherent()) - dma_cache_maint(dma_to_virt(dev, handle) + offset, size, dir); + __dma_single_cpu_to_dev(dma_to_virt(dev, handle) + offset, size, dir); } static inline void dma_sync_single_for_cpu(struct device *dev, |