LXR linux/arch/microblaze/kernel/dma.c

   1/*
   2 * Copyright (C) 2009-2010 PetaLogix
   3 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
   4 *
   5 * Provide default implementations of the DMA mapping callbacks for
   6 * directly mapped busses.
   7 */
   8
   9#include <linux/device.h>
  10#include <linux/dma-mapping.h>
  11#include <linux/gfp.h>
  12#include <linux/dma-debug.h>
  13#include <asm/bug.h>
  14#include <asm/cacheflush.h>
  15
  16/*
  17 * Generic direct DMA implementation
  18 *
  19 * This implementation supports a per-device offset that can be applied if
  20 * the address at which memory is visible to devices is not 0. Platform code
  21 * can set archdata.dma_data to an unsigned long holding the offset. By
  22 * default the offset is PCI_DRAM_OFFSET.
  23 */
  24static inline void __dma_sync_page(unsigned long paddr, unsigned long offset,
  25                                size_t size, enum dma_data_direction direction)
  26{
  27        switch (direction) {
  28        case DMA_TO_DEVICE:
  29                flush_dcache_range(paddr + offset, paddr + offset + size);
  30                break;
  31        case DMA_FROM_DEVICE:
  32                invalidate_dcache_range(paddr + offset, paddr + offset + size);
  33                break;
  34        default:
  35                BUG();
  36        }
  37}
  38
  39static unsigned long get_dma_direct_offset(struct device *dev)
  40{
  41        if (likely(dev))
  42                return (unsigned long)dev->archdata.dma_data;
  43
  44        return PCI_DRAM_OFFSET; /* FIXME Not sure if is correct */
  45}
  46
  47#define NOT_COHERENT_CACHE
  48
  49static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
  50                                dma_addr_t *dma_handle, gfp_t flag)
  51{
  52#ifdef NOT_COHERENT_CACHE
  53        return consistent_alloc(flag, size, dma_handle);
  54#else
  55        void *ret;
  56        struct page *page;
  57        int node = dev_to_node(dev);
  58
  59        /* ignore region specifiers */
  60        flag  &= ~(__GFP_HIGHMEM);
  61
  62        page = alloc_pages_node(node, flag, get_order(size));
  63        if (page == NULL)
  64                return NULL;
  65        ret = page_address(page);
  66        memset(ret, 0, size);
  67        *dma_handle = virt_to_phys(ret) + get_dma_direct_offset(dev);
  68
  69        return ret;
  70#endif
  71}
  72
  73static void dma_direct_free_coherent(struct device *dev, size_t size,
  74                              void *vaddr, dma_addr_t dma_handle)
  75{
  76#ifdef NOT_COHERENT_CACHE
  77        consistent_free(size, vaddr);
  78#else
  79        free_pages((unsigned long)vaddr, get_order(size));
  80#endif
  81}
  82
  83static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
  84                             int nents, enum dma_data_direction direction,
  85                             struct dma_attrs *attrs)
  86{
  87        struct scatterlist *sg;
  88        int i;
  89
  90        /* FIXME this part of code is untested */
  91        for_each_sg(sgl, sg, nents, i) {
  92                sg->dma_address = sg_phys(sg) + get_dma_direct_offset(dev);
  93                __dma_sync_page(page_to_phys(sg_page(sg)), sg->offset,
  94                                                        sg->length, direction);
  95        }
  96
  97        return nents;
  98}
  99
 100static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
 101                                int nents, enum dma_data_direction direction,
 102                                struct dma_attrs *attrs)
 103{
 104}
 105
 106static int dma_direct_dma_supported(struct device *dev, u64 mask)
 107{
 108        return 1;
 109}
 110
 111static inline dma_addr_t dma_direct_map_page(struct device *dev,
 112                                             struct page *page,
 113                                             unsigned long offset,
 114                                             size_t size,
 115                                             enum dma_data_direction direction,
 116                                             struct dma_attrs *attrs)
 117{
 118        __dma_sync_page(page_to_phys(page), offset, size, direction);
 119        return page_to_phys(page) + offset + get_dma_direct_offset(dev);
 120}
 121
 122static inline void dma_direct_unmap_page(struct device *dev,
 123                                         dma_addr_t dma_address,
 124                                         size_t size,
 125                                         enum dma_data_direction direction,
 126                                         struct dma_attrs *attrs)
 127{
 128/* There is not necessary to do cache cleanup
 129 *
 130 * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
 131 * dma_address is physical address
 132 */
 133        __dma_sync_page(dma_address, 0 , size, direction);
 134}
 135
 136struct dma_map_ops dma_direct_ops = {
 137        .alloc_coherent = dma_direct_alloc_coherent,
 138        .free_coherent  = dma_direct_free_coherent,
 139        .map_sg         = dma_direct_map_sg,
 140        .unmap_sg       = dma_direct_unmap_sg,
 141        .dma_supported  = dma_direct_dma_supported,
 142        .map_page       = dma_direct_map_page,
 143        .unmap_page     = dma_direct_unmap_page,
 144};
 145EXPORT_SYMBOL(dma_direct_ops);
 146
 147/* Number of entries preallocated for DMA-API debugging */
 148#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 149
 150static int __init dma_init(void)
 151{
 152       dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 153
 154       return 0;
 155}
 156fs_initcall(dma_init);
 157