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 void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
  72                                 int nents, enum dma_data_direction direction,
  73                                 struct dma_attrs *attrs)
  74 {
  75 }
  76
  77 static int dma_direct_dma_supported(struct device *dev, u64 mask)
  78 {
  79         return 1;
  80 }
  81
  82 static inline dma_addr_t dma_direct_map_page(struct device *dev,
  83                                              struct page *page,
  84                                              unsigned long offset,
  85                                              size_t size,
  86                                              enum dma_data_direction direction,
  87                                              struct dma_attrs *attrs)
  88 {
  89         __dma_sync(page_to_phys(page) + offset, size, direction);
  90         return page_to_phys(page) + offset;
  91 }
  92
  93 static inline void dma_direct_unmap_page(struct device *dev,
  94                                          dma_addr_t dma_address,
  95                                          size_t size,
  96                                          enum dma_data_direction direction,
  97                                          struct dma_attrs *attrs)
  98 {
  99 /* There is not necessary to do cache cleanup
 100  *
 101  * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
 102  * dma_address is physical address
 103  */
 104         __dma_sync(dma_address, size, direction);
 105 }
 106
 107 static inline void
 108 dma_direct_sync_single_for_cpu(struct device *dev,
 109                                dma_addr_t dma_handle, size_t size,
 110                                enum dma_data_direction direction)
 111 {
 112         /*
 113          * It's pointless to flush the cache as the memory segment
 114          * is given to the CPU
 115          */
 116
 117         if (direction == DMA_FROM_DEVICE)
 118                 __dma_sync(dma_handle, size, direction);
 119 }
 120
 121 static inline void
 122 dma_direct_sync_single_for_device(struct device *dev,
 123                                   dma_addr_t dma_handle, size_t size,
 124                                   enum dma_data_direction direction)
 125 {
 126         /*
 127          * It's pointless to invalidate the cache if the device isn't
 128          * supposed to write to the relevant region
 129          */
 130
 131         if (direction == DMA_TO_DEVICE)
 132                 __dma_sync(dma_handle, size, direction);
 133 }
 134
 135 static inline void
 136 dma_direct_sync_sg_for_cpu(struct device *dev,
 137                            struct scatterlist *sgl, int nents,
 138                            enum dma_data_direction direction)
 139 {
 140         struct scatterlist *sg;
 141         int i;
 142
 143         /* FIXME this part of code is untested */
 144         if (direction == DMA_FROM_DEVICE)
 145                 for_each_sg(sgl, sg, nents, i)
 146                         __dma_sync(sg->dma_address, sg->length, direction);
 147 }
 148
 149 static inline void
 150 dma_direct_sync_sg_for_device(struct device *dev,
 151                               struct scatterlist *sgl, int nents,
 152                               enum dma_data_direction direction)
 153 {
 154         struct scatterlist *sg;
 155         int i;
 156
 157         /* FIXME this part of code is untested */
 158         if (direction == DMA_TO_DEVICE)
 159                 for_each_sg(sgl, sg, nents, i)
 160                         __dma_sync(sg->dma_address, sg->length, direction);
 161 }
 162
 163 struct dma_map_ops dma_direct_ops = {
 164         .alloc          = dma_direct_alloc_coherent,
 165         .free           = dma_direct_free_coherent,
 166         .map_sg         = dma_direct_map_sg,
 167         .unmap_sg       = dma_direct_unmap_sg,
 168         .dma_supported  = dma_direct_dma_supported,
 169         .map_page       = dma_direct_map_page,
 170         .unmap_page     = dma_direct_unmap_page,
 171         .sync_single_for_cpu            = dma_direct_sync_single_for_cpu,
 172         .sync_single_for_device         = dma_direct_sync_single_for_device,
 173         .sync_sg_for_cpu                = dma_direct_sync_sg_for_cpu,
 174         .sync_sg_for_device             = dma_direct_sync_sg_for_device,
 175 };
 176 EXPORT_SYMBOL(dma_direct_ops);
 177
 178 /* Number of entries preallocated for DMA-API debugging */
 179 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 180
 181 static int __init dma_init(void)
 182 {
 183         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 184
 185         return 0;
 186 }
 187 fs_initcall(dma_init);