| /* |
| * Copyright (C) 2009-2010 PetaLogix |
| * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation |
| * |
| * Provide default implementations of the DMA mapping callbacks for |
| * directly mapped busses. |
| */ |
| |
| #include <linux/device.h> |
| #include <linux/dma-mapping.h> |
| #include <linux/gfp.h> |
| #include <linux/dma-debug.h> |
| #include <linux/export.h> |
| #include <asm/bug.h> |
| |
| /* |
| * Generic direct DMA implementation |
| * |
| * This implementation supports a per-device offset that can be applied if |
| * the address at which memory is visible to devices is not 0. Platform code |
| * can set archdata.dma_data to an unsigned long holding the offset. By |
| * default the offset is PCI_DRAM_OFFSET. |
| */ |
| |
| static unsigned long get_dma_direct_offset(struct device *dev) |
| { |
| if (likely(dev)) |
| return (unsigned long)dev->archdata.dma_data; |
| |
| return PCI_DRAM_OFFSET; /* FIXME Not sure if is correct */ |
| } |
| |
| #define NOT_COHERENT_CACHE |
| |
| static void *dma_direct_alloc_coherent(struct device *dev, size_t size, |
| dma_addr_t *dma_handle, gfp_t flag) |
| { |
| #ifdef NOT_COHERENT_CACHE |
| return consistent_alloc(flag, size, dma_handle); |
| #else |
| void *ret; |
| struct page *page; |
| int node = dev_to_node(dev); |
| |
| /* ignore region specifiers */ |
| flag &= ~(__GFP_HIGHMEM); |
| |
| page = alloc_pages_node(node, flag, get_order(size)); |
| if (page == NULL) |
| return NULL; |
| ret = page_address(page); |
| memset(ret, 0, size); |
| *dma_handle = virt_to_phys(ret) + get_dma_direct_offset(dev); |
| |
| return ret; |
| #endif |
| } |
| |
| static void dma_direct_free_coherent(struct device *dev, size_t size, |
| void *vaddr, dma_addr_t dma_handle) |
| { |
| #ifdef NOT_COHERENT_CACHE |
| consistent_free(size, vaddr); |
| #else |
| free_pages((unsigned long)vaddr, get_order(size)); |
| #endif |
| } |
| |
| static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, |
| int nents, enum dma_data_direction direction, |
| struct dma_attrs *attrs) |
| { |
| struct scatterlist *sg; |
| int i; |
| |
| /* FIXME this part of code is untested */ |
| for_each_sg(sgl, sg, nents, i) { |
| sg->dma_address = sg_phys(sg) + get_dma_direct_offset(dev); |
| __dma_sync(page_to_phys(sg_page(sg)) + sg->offset, |
| sg->length, direction); |
| } |
| |
| return nents; |
| } |
| |
| static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg, |
| int nents, enum dma_data_direction direction, |
| struct dma_attrs *attrs) |
| { |
| } |
| |
| static int dma_direct_dma_supported(struct device *dev, u64 mask) |
| { |
| return 1; |
| } |
| |
| static inline dma_addr_t dma_direct_map_page(struct device *dev, |
| struct page *page, |
| unsigned long offset, |
| size_t size, |
| enum dma_data_direction direction, |
| struct dma_attrs *attrs) |
| { |
| __dma_sync(page_to_phys(page) + offset, size, direction); |
| return page_to_phys(page) + offset + get_dma_direct_offset(dev); |
| } |
| |
| static inline void dma_direct_unmap_page(struct device *dev, |
| dma_addr_t dma_address, |
| size_t size, |
| enum dma_data_direction direction, |
| struct dma_attrs *attrs) |
| { |
| /* There is not necessary to do cache cleanup |
| * |
| * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and |
| * dma_address is physical address |
| */ |
| __dma_sync(dma_address, size, direction); |
| } |
| |
| static inline void |
| dma_direct_sync_single_for_cpu(struct device *dev, |
| dma_addr_t dma_handle, size_t size, |
| enum dma_data_direction direction) |
| { |
| /* |
| * It's pointless to flush the cache as the memory segment |
| * is given to the CPU |
| */ |
| |
| if (direction == DMA_FROM_DEVICE) |
| __dma_sync(dma_handle, size, direction); |
| } |
| |
| static inline void |
| dma_direct_sync_single_for_device(struct device *dev, |
| dma_addr_t dma_handle, size_t size, |
| enum dma_data_direction direction) |
| { |
| /* |
| * It's pointless to invalidate the cache if the device isn't |
| * supposed to write to the relevant region |
| */ |
| |
| if (direction == DMA_TO_DEVICE) |
| __dma_sync(dma_handle, size, direction); |
| } |
| |
| static inline void |
| dma_direct_sync_sg_for_cpu(struct device *dev, |
| struct scatterlist *sgl, int nents, |
| enum dma_data_direction direction) |
| { |
| struct scatterlist *sg; |
| int i; |
| |
| /* FIXME this part of code is untested */ |
| if (direction == DMA_FROM_DEVICE) |
| for_each_sg(sgl, sg, nents, i) |
| __dma_sync(sg->dma_address, sg->length, direction); |
| } |
| |
| static inline void |
| dma_direct_sync_sg_for_device(struct device *dev, |
| struct scatterlist *sgl, int nents, |
| enum dma_data_direction direction) |
| { |
| struct scatterlist *sg; |
| int i; |
| |
| /* FIXME this part of code is untested */ |
| if (direction == DMA_TO_DEVICE) |
| for_each_sg(sgl, sg, nents, i) |
| __dma_sync(sg->dma_address, sg->length, direction); |
| } |
| |
| struct dma_map_ops dma_direct_ops = { |
| .alloc_coherent = dma_direct_alloc_coherent, |
| .free_coherent = dma_direct_free_coherent, |
| .map_sg = dma_direct_map_sg, |
| .unmap_sg = dma_direct_unmap_sg, |
| .dma_supported = dma_direct_dma_supported, |
| .map_page = dma_direct_map_page, |
| .unmap_page = dma_direct_unmap_page, |
| .sync_single_for_cpu = dma_direct_sync_single_for_cpu, |
| .sync_single_for_device = dma_direct_sync_single_for_device, |
| .sync_sg_for_cpu = dma_direct_sync_sg_for_cpu, |
| .sync_sg_for_device = dma_direct_sync_sg_for_device, |
| }; |
| EXPORT_SYMBOL(dma_direct_ops); |
| |
| /* Number of entries preallocated for DMA-API debugging */ |
| #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16) |
| |
| static int __init dma_init(void) |
| { |
| dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); |
| |
| return 0; |
| } |
| fs_initcall(dma_init); |