SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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  */
  24 static 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
  39 static 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
  49 static 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
  73 static 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
  83 static 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
 100 static 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
 106 static int dma_direct_dma_supported(struct device *dev, u64 mask)
 107 {
 108         return 1;
 109 }
 110
 111 static 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
 122 static 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
 136 struct 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 };
 145 EXPORT_SYMBOL(dma_direct_ops);
 146
 147 /* Number of entries preallocated for DMA-API debugging */
 148 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 149
 150 static int __init dma_init(void)
 151 {
 152        dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 153
 154        return 0;
 155 }
 156 fs_initcall(dma_init);