diff options
Diffstat (limited to 'arch/microblaze/kernel/dma.c')
| -rw-r--r-- | arch/microblaze/kernel/dma.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/arch/microblaze/kernel/dma.c b/arch/microblaze/kernel/dma.c new file mode 100644 index 00000000000..4d5b0311601 --- /dev/null +++ b/arch/microblaze/kernel/dma.c @@ -0,0 +1,156 @@ +/* + * 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/dma-debug.h> +#include <asm/bug.h> +#include <asm/cacheflush.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 inline void __dma_sync_page(unsigned long paddr, unsigned long offset, + size_t size, enum dma_data_direction direction) +{ + switch (direction) { + case DMA_TO_DEVICE: + flush_dcache_range(paddr + offset, paddr + offset + size); + break; + case DMA_FROM_DEVICE: + invalidate_dcache_range(paddr + offset, paddr + offset + size); + break; + default: + BUG(); + } +} + +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(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); + sg->dma_length = sg->length; + __dma_sync_page(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(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_page(dma_address, 0 , size, 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, +}; +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); |