#ifndef ASMARM_DMA_MAPPING_H #define ASMARM_DMA_MAPPING_H #ifdef __KERNEL__ #include <linux/mm.h> /* need struct page */ #include <linux/scatterlist.h> /* * 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_*) */ extern void dma_cache_maint(const void *kaddr, size_t size, int rw); /* * 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 * to this function. * * FIXME: This should really be a platform specific issue - we should * return false if GFP_DMA allocations may not satisfy the supplied 'mask'. */ static inline int dma_supported(struct device *dev, u64 mask) { return dev->dma_mask && *dev->dma_mask != 0; } static inline int dma_set_mask(struct device *dev, u64 dma_mask) { if (!dev->dma_mask || !dma_supported(dev, dma_mask)) return -EIO; *dev->dma_mask = dma_mask; return 0; } static inline int dma_get_cache_alignment(void) { return 32; } static inline int dma_is_consistent(struct device *dev, dma_addr_t handle) { return !!arch_is_coherent(); } /* * DMA errors are defined by all-bits-set in the DMA address. */ static inline int dma_mapping_error(dma_addr_t dma_addr) { return dma_addr == ~0; } /* * Dummy noncoherent implementation. We don't provide a dma_cache_sync * function so drivers using this API are highlighted with build warnings. */ static inline void * dma_alloc_noncoherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp) { return NULL; } static inline void dma_free_noncoherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle) { } /** * dma_alloc_coherent - allocate consistent memory for DMA * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @size: required memory size * @handle: bus-specific DMA address * * Allocate some uncached, unbuffered memory for a device for * performing DMA. This function allocates pages, and will * return the CPU-viewed address, and sets @handle to be the * device-viewed address. */ extern void * dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp); /** * dma_free_coherent - free memory allocated by dma_alloc_coherent * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @size: size of memory originally requested in dma_alloc_coherent * @cpu_addr: CPU-view address returned from dma_alloc_coherent * @handle: device-view address returned from dma_alloc_coherent * * Free (and unmap) a DMA buffer previously allocated by * dma_alloc_coherent(). * * References to memory and mappings associated with cpu_addr/handle * during and after this call executing are illegal. */ extern void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle); /** * dma_mmap_coherent - map a coherent DMA allocation into user space * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @vma: vm_area_struct describing requested user mapping * @cpu_addr: kernel CPU-view address returned from dma_alloc_coherent * @handle: device-view address returned from dma_alloc_coherent * @size: size of memory originally requested in dma_alloc_coherent * * Map a coherent DMA buffer previously allocated by dma_alloc_coherent * into user space. The coherent DMA buffer must not be freed by the * driver until the user space mapping has been released. */ int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t handle, size_t size); /** * dma_alloc_writecombine - allocate writecombining memory for DMA * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @size: required memory size * @handle: bus-specific DMA address * * Allocate some uncached, buffered memory for a device for * performing DMA. This function allocates pages, and will * return the CPU-viewed address, and sets @handle to be the * device-viewed address. */ extern void * dma_alloc_writecombine(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp); #define dma_free_writecombine(dev,size,cpu_addr,handle) \ dma_free_coherent(dev,size,cpu_addr,handle) int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t handle, size_t size); /** * dma_map_single - map a single buffer for streaming DMA * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @cpu_addr: CPU direct mapped address of buffer * @size: size of buffer to map * @dir: DMA transfer direction * * Ensure that any data held in the cache is appropriately discarded * or written back. * * The device owns this memory once this call has completed. The CPU * can regain ownership by calling dma_unmap_single() or * dma_sync_single_for_cpu(). */ #ifndef CONFIG_DMABOUNCE static inline dma_addr_t dma_map_single(struct device *dev, void *cpu_addr, size_t size, enum dma_data_direction dir) { if (!arch_is_coherent()) dma_cache_maint(cpu_addr, size, dir); return virt_to_dma(dev, (unsigned long)cpu_addr); } #else extern dma_addr_t dma_map_single(struct device *,void *, size_t, enum dma_data_direction); #endif /** * dma_map_page - map a portion of a page for streaming DMA * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @page: page that buffer resides in * @offset: offset into page for start of buffer * @size: size of buffer to map * @dir: DMA transfer direction * * Ensure that any data held in the cache is appropriately discarded * or written back. * * The device owns this memory once this call has completed. The CPU * can regain ownership by calling dma_unmap_page() or * dma_sync_single_for_cpu(). */ static inline dma_addr_t dma_map_page(struct device *dev, struct page *page, unsigned long offset, size_t size, enum dma_data_direction dir) { return dma_map_single(dev, page_address(page) + offset, size, (int)dir); } /** * dma_unmap_single - unmap a single buffer previously mapped * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @handle: DMA address of buffer * @size: size of buffer to map * @dir: DMA transfer direction * * Unmap a single streaming mode DMA translation. The handle and size * must match what was provided in the previous dma_map_single() call. * All other usages are undefined. * * After this call, reads by the CPU to the buffer are guaranteed to see * whatever the device wrote there. */ #ifndef CONFIG_DMABOUNCE static inline void dma_unmap_single(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { /* nothing to do */ } #else extern void dma_unmap_single(struct device *, dma_addr_t, size_t, enum dma_data_direction); #endif /** * dma_unmap_page - unmap a buffer previously mapped through dma_map_page() * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @handle: DMA address of buffer * @size: size of buffer to map * @dir: DMA transfer direction * * Unmap a single streaming mode DMA translation. The handle and size * must match what was provided in the previous dma_map_single() call. * All other usages are undefined. * * After this call, reads by the CPU to the buffer are guaranteed to see * whatever the device wrote there. */ static inline void dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { dma_unmap_single(dev, handle, size, (int)dir); } /** * dma_map_sg - map a set of SG buffers for streaming mode DMA * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @sg: list of buffers * @nents: number of buffers to map * @dir: DMA transfer direction * * Map a set of buffers described by scatterlist in streaming * mode for DMA. This is the scatter-gather version of the * above dma_map_single interface. Here the scatter gather list * elements are each tagged with the appropriate dma address * and length. They are obtained via sg_dma_{address,length}(SG). * * NOTE: An implementation may be able to use a smaller number of * DMA address/length pairs than there are SG table elements. * (for example via virtual mapping capabilities) * The routine returns the number of addr/length pairs actually * used, at most nents. * * Device ownership issues as mentioned above for dma_map_single are * the same here. */ #ifndef CONFIG_DMABOUNCE static inline int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir) { int i; for (i = 0; i < nents; i++, sg++) { char *virt; sg->dma_address = page_to_dma(dev, sg_page(sg)) + sg->offset; virt = sg_virt(sg); if (!arch_is_coherent()) dma_cache_maint(virt, sg->length, dir); } return nents; } #else extern int dma_map_sg(struct device *, struct scatterlist *, int, enum dma_data_direction); #endif /** * dma_unmap_sg - unmap a set of SG buffers mapped by dma_map_sg * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @sg: list of buffers * @nents: number of buffers to map * @dir: DMA transfer direction * * Unmap a set of streaming mode DMA translations. * Again, CPU read rules concerning calls here are the same as for * dma_unmap_single() above. */ #ifndef CONFIG_DMABOUNCE static inline void dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir) { /* nothing to do */ } #else extern void dma_unmap_sg(struct device *, struct scatterlist *, int, enum dma_data_direction); #endif /** * dma_sync_single_for_cpu * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @handle: DMA address of buffer * @size: size of buffer to map * @dir: DMA transfer direction * * Make physical memory consistent for a single streaming mode DMA * translation after a transfer. * * If you perform a dma_map_single() but wish to interrogate the * buffer using the cpu, yet do not wish to teardown the PCI dma * mapping, you must call this function before doing so. At the * next point you give the PCI dma address back to the card, you * must first the perform a dma_sync_for_device, and then the * device again owns the buffer. */ #ifndef CONFIG_DMABOUNCE static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { if (!arch_is_coherent()) dma_cache_maint((void *)dma_to_virt(dev, handle), size, dir); } static inline void dma_sync_single_for_device(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { if (!arch_is_coherent()) dma_cache_maint((void *)dma_to_virt(dev, handle), size, dir); } #else extern void dma_sync_single_for_cpu(struct device*, dma_addr_t, size_t, enum dma_data_direction); extern void dma_sync_single_for_device(struct device*, dma_addr_t, size_t, enum dma_data_direction); #endif /** * dma_sync_sg_for_cpu * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices * @sg: list of buffers * @nents: number of buffers to map * @dir: DMA transfer direction * * Make physical memory consistent for a set of streaming * mode DMA translations after a transfer. * * The same as dma_sync_single_for_* but for a scatter-gather list, * same rules and usage. */ #ifndef CONFIG_DMABOUNCE static inline void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir) { int i; for (i = 0; i < nents; i++, sg++) { char *virt = sg_virt(sg); if (!arch_is_coherent()) dma_cache_maint(virt, sg->length, dir); } } static inline void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir) { int i; for (i = 0; i < nents; i++, sg++) { char *virt = sg_virt(sg); if (!arch_is_coherent()) dma_cache_maint(virt, sg->length, dir); } } #else extern void dma_sync_sg_for_cpu(struct device*, struct scatterlist*, int, enum dma_data_direction); extern void dma_sync_sg_for_device(struct device*, struct scatterlist*, int, enum dma_data_direction); #endif #ifdef CONFIG_DMABOUNCE /* * For SA-1111, IXP425, and ADI systems the dma-mapping functions are "magic" * and utilize bounce buffers as needed to work around limited DMA windows. * * On the SA-1111, a bug limits DMA to only certain regions of RAM. * On the IXP425, the PCI inbound window is 64MB (256MB total RAM) * On some ADI engineering systems, PCI inbound window is 32MB (12MB total RAM) * * The following are helper functions used by the dmabounce subystem * */ /** * dmabounce_register_dev * * @dev: valid struct device pointer * @small_buf_size: size of buffers to use with small buffer pool * @large_buf_size: size of buffers to use with large buffer pool (can be 0) * * This function should be called by low-level platform code to register * a device as requireing DMA buffer bouncing. The function will allocate * appropriate DMA pools for the device. * */ extern int dmabounce_register_dev(struct device *, unsigned long, unsigned long); /** * dmabounce_unregister_dev * * @dev: valid struct device pointer * * This function should be called by low-level platform code when device * that was previously registered with dmabounce_register_dev is removed * from the system. * */ extern void dmabounce_unregister_dev(struct device *); /** * dma_needs_bounce * * @dev: valid struct device pointer * @dma_handle: dma_handle of unbounced buffer * @size: size of region being mapped * * Platforms that utilize the dmabounce mechanism must implement * this function. * * The dmabounce routines call this function whenever a dma-mapping * is requested to determine whether a given buffer needs to be bounced * or not. The function must return 0 if the buffer is OK for * DMA access and 1 if the buffer needs to be bounced. * */ extern int dma_needs_bounce(struct device*, dma_addr_t, size_t); #endif /* CONFIG_DMABOUNCE */ #endif /* __KERNEL__ */ #endif