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 <linux/export.h>
  14 #include <linux/bug.h>
  15
  16 #define NOT_COHERENT_CACHE
  17
  18 static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
  19                                        dma_addr_t *dma_handle, gfp_t flag,
  20                                        struct dma_attrs *attrs)
  21 {
  22 #ifdef NOT_COHERENT_CACHE
  23         return consistent_alloc(flag, size, dma_handle);
  24 #else
  25         void *ret;
  26         struct page *page;
  27         int node = dev_to_node(dev);
  28
  29         /* ignore region specifiers */
  30         flag  &= ~(__GFP_HIGHMEM);
  31
  32         page = alloc_pages_node(node, flag, get_order(size));
  33         if (page == NULL)
  34                 return NULL;
  35         ret = page_address(page);
  36         memset(ret, 0, size);
  37         *dma_handle = virt_to_phys(ret);
  38
  39         return ret;
  40 #endif
  41 }
  42
  43 static void dma_direct_free_coherent(struct device *dev, size_t size,
  44                                      void *vaddr, dma_addr_t dma_handle,
  45                                      struct dma_attrs *attrs)
  46 {
  47 #ifdef NOT_COHERENT_CACHE
  48         consistent_free(size, vaddr);
  49 #else
  50         free_pages((unsigned long)vaddr, get_order(size));
  51 #endif
  52 }
  53
  54 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
  55                              int nents, enum dma_data_direction direction,
  56                              struct dma_attrs *attrs)
  57 {
  58         struct scatterlist *sg;
  59         int i;
  60
  61         /* FIXME this part of code is untested */
  62         for_each_sg(sgl, sg, nents, i) {
  63                 sg->dma_address = sg_phys(sg);
  64                 __dma_sync(page_to_phys(sg_page(sg)) + sg->offset,
  65                                                         sg->length, direction);
  66         }
  67
  68         return nents;
  69 }
  70
  71 static int dma_direct_dma_supported(struct device *dev, u64 mask)
  72 {
  73         return 1;
  74 }
  75
  76 static inline dma_addr_t dma_direct_map_page(struct device *dev,
  77                                              struct page *page,
  78                                              unsigned long offset,
  79                                              size_t size,
  80                                              enum dma_data_direction direction,
  81                                              struct dma_attrs *attrs)
  82 {
  83         __dma_sync(page_to_phys(page) + offset, size, direction);
  84         return page_to_phys(page) + offset;
  85 }
  86
  87 static inline void dma_direct_unmap_page(struct device *dev,
  88                                          dma_addr_t dma_address,
  89                                          size_t size,
  90                                          enum dma_data_direction direction,
  91                                          struct dma_attrs *attrs)
  92 {
  93 /* There is not necessary to do cache cleanup
  94  *
  95  * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
  96  * dma_address is physical address
  97  */
  98         __dma_sync(dma_address, size, direction);
  99 }
 100
 101 static inline void
 102 dma_direct_sync_single_for_cpu(struct device *dev,
 103                                dma_addr_t dma_handle, size_t size,
 104                                enum dma_data_direction direction)
 105 {
 106         /*
 107          * It's pointless to flush the cache as the memory segment
 108          * is given to the CPU
 109          */
 110
 111         if (direction == DMA_FROM_DEVICE)
 112                 __dma_sync(dma_handle, size, direction);
 113 }
 114
 115 static inline void
 116 dma_direct_sync_single_for_device(struct device *dev,
 117                                   dma_addr_t dma_handle, size_t size,
 118                                   enum dma_data_direction direction)
 119 {
 120         /*
 121          * It's pointless to invalidate the cache if the device isn't
 122          * supposed to write to the relevant region
 123          */
 124
 125         if (direction == DMA_TO_DEVICE)
 126                 __dma_sync(dma_handle, size, direction);
 127 }
 128
 129 static inline void
 130 dma_direct_sync_sg_for_cpu(struct device *dev,
 131                            struct scatterlist *sgl, int nents,
 132                            enum dma_data_direction direction)
 133 {
 134         struct scatterlist *sg;
 135         int i;
 136
 137         /* FIXME this part of code is untested */
 138         if (direction == DMA_FROM_DEVICE)
 139                 for_each_sg(sgl, sg, nents, i)
 140                         __dma_sync(sg->dma_address, sg->length, direction);
 141 }
 142
 143 static inline void
 144 dma_direct_sync_sg_for_device(struct device *dev,
 145                               struct scatterlist *sgl, int nents,
 146                               enum dma_data_direction direction)
 147 {
 148         struct scatterlist *sg;
 149         int i;
 150
 151         /* FIXME this part of code is untested */
 152         if (direction == DMA_TO_DEVICE)
 153                 for_each_sg(sgl, sg, nents, i)
 154                         __dma_sync(sg->dma_address, sg->length, direction);
 155 }
 156
 157 struct dma_map_ops dma_direct_ops = {
 158         .alloc          = dma_direct_alloc_coherent,
 159         .free           = dma_direct_free_coherent,
 160         .map_sg         = dma_direct_map_sg,
 161         .dma_supported  = dma_direct_dma_supported,
 162         .map_page       = dma_direct_map_page,
 163         .unmap_page     = dma_direct_unmap_page,
 164         .sync_single_for_cpu            = dma_direct_sync_single_for_cpu,
 165         .sync_single_for_device         = dma_direct_sync_single_for_device,
 166         .sync_sg_for_cpu                = dma_direct_sync_sg_for_cpu,
 167         .sync_sg_for_device             = dma_direct_sync_sg_for_device,
 168 };
 169 EXPORT_SYMBOL(dma_direct_ops);
 170
 171 /* Number of entries preallocated for DMA-API debugging */
 172 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 173
 174 static int __init dma_init(void)
 175 {
 176         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 177
 178         return 0;
 179 }
 180 fs_initcall(dma_init);