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 <asm/bug.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
  25 static unsigned long get_dma_direct_offset(struct device *dev)
  26 {
  27         if (likely(dev))
  28                 return (unsigned long)dev->archdata.dma_data;
  29
  30         return PCI_DRAM_OFFSET; /* FIXME Not sure if is correct */
  31 }
  32
  33 #define NOT_COHERENT_CACHE
  34
  35 static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
  36                                        dma_addr_t *dma_handle, gfp_t flag,
  37                                        struct dma_attrs *attrs)
  38 {
  39 #ifdef NOT_COHERENT_CACHE
  40         return consistent_alloc(flag, size, dma_handle);
  41 #else
  42         void *ret;
  43         struct page *page;
  44         int node = dev_to_node(dev);
  45
  46         /* ignore region specifiers */
  47         flag  &= ~(__GFP_HIGHMEM);
  48
  49         page = alloc_pages_node(node, flag, get_order(size));
  50         if (page == NULL)
  51                 return NULL;
  52         ret = page_address(page);
  53         memset(ret, 0, size);
  54         *dma_handle = virt_to_phys(ret) + get_dma_direct_offset(dev);
  55
  56         return ret;
  57 #endif
  58 }
  59
  60 static void dma_direct_free_coherent(struct device *dev, size_t size,
  61                                      void *vaddr, dma_addr_t dma_handle,
  62                                      struct dma_attrs *attrs)
  63 {
  64 #ifdef NOT_COHERENT_CACHE
  65         consistent_free(size, vaddr);
  66 #else
  67         free_pages((unsigned long)vaddr, get_order(size));
  68 #endif
  69 }
  70
  71 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
  72                              int nents, enum dma_data_direction direction,
  73                              struct dma_attrs *attrs)
  74 {
  75         struct scatterlist *sg;
  76         int i;
  77
  78         /* FIXME this part of code is untested */
  79         for_each_sg(sgl, sg, nents, i) {
  80                 sg->dma_address = sg_phys(sg) + get_dma_direct_offset(dev);
  81                 __dma_sync(page_to_phys(sg_page(sg)) + sg->offset,
  82                                                         sg->length, direction);
  83         }
  84
  85         return nents;
  86 }
  87
  88 static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
  89                                 int nents, enum dma_data_direction direction,
  90                                 struct dma_attrs *attrs)
  91 {
  92 }
  93
  94 static int dma_direct_dma_supported(struct device *dev, u64 mask)
  95 {
  96         return 1;
  97 }
  98
  99 static inline dma_addr_t dma_direct_map_page(struct device *dev,
 100                                              struct page *page,
 101                                              unsigned long offset,
 102                                              size_t size,
 103                                              enum dma_data_direction direction,
 104                                              struct dma_attrs *attrs)
 105 {
 106         __dma_sync(page_to_phys(page) + offset, size, direction);
 107         return page_to_phys(page) + offset + get_dma_direct_offset(dev);
 108 }
 109
 110 static inline void dma_direct_unmap_page(struct device *dev,
 111                                          dma_addr_t dma_address,
 112                                          size_t size,
 113                                          enum dma_data_direction direction,
 114                                          struct dma_attrs *attrs)
 115 {
 116 /* There is not necessary to do cache cleanup
 117  *
 118  * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
 119  * dma_address is physical address
 120  */
 121         __dma_sync(dma_address, size, direction);
 122 }
 123
 124 static inline void
 125 dma_direct_sync_single_for_cpu(struct device *dev,
 126                                dma_addr_t dma_handle, size_t size,
 127                                enum dma_data_direction direction)
 128 {
 129         /*
 130          * It's pointless to flush the cache as the memory segment
 131          * is given to the CPU
 132          */
 133
 134         if (direction == DMA_FROM_DEVICE)
 135                 __dma_sync(dma_handle, size, direction);
 136 }
 137
 138 static inline void
 139 dma_direct_sync_single_for_device(struct device *dev,
 140                                   dma_addr_t dma_handle, size_t size,
 141                                   enum dma_data_direction direction)
 142 {
 143         /*
 144          * It's pointless to invalidate the cache if the device isn't
 145          * supposed to write to the relevant region
 146          */
 147
 148         if (direction == DMA_TO_DEVICE)
 149                 __dma_sync(dma_handle, size, direction);
 150 }
 151
 152 static inline void
 153 dma_direct_sync_sg_for_cpu(struct device *dev,
 154                            struct scatterlist *sgl, int nents,
 155                            enum dma_data_direction direction)
 156 {
 157         struct scatterlist *sg;
 158         int i;
 159
 160         /* FIXME this part of code is untested */
 161         if (direction == DMA_FROM_DEVICE)
 162                 for_each_sg(sgl, sg, nents, i)
 163                         __dma_sync(sg->dma_address, sg->length, direction);
 164 }
 165
 166 static inline void
 167 dma_direct_sync_sg_for_device(struct device *dev,
 168                               struct scatterlist *sgl, int nents,
 169                               enum dma_data_direction direction)
 170 {
 171         struct scatterlist *sg;
 172         int i;
 173
 174         /* FIXME this part of code is untested */
 175         if (direction == DMA_TO_DEVICE)
 176                 for_each_sg(sgl, sg, nents, i)
 177                         __dma_sync(sg->dma_address, sg->length, direction);
 178 }
 179
 180 struct dma_map_ops dma_direct_ops = {
 181         .alloc          = dma_direct_alloc_coherent,
 182         .free           = dma_direct_free_coherent,
 183         .map_sg         = dma_direct_map_sg,
 184         .unmap_sg       = dma_direct_unmap_sg,
 185         .dma_supported  = dma_direct_dma_supported,
 186         .map_page       = dma_direct_map_page,
 187         .unmap_page     = dma_direct_unmap_page,
 188         .sync_single_for_cpu            = dma_direct_sync_single_for_cpu,
 189         .sync_single_for_device         = dma_direct_sync_single_for_device,
 190         .sync_sg_for_cpu                = dma_direct_sync_sg_for_cpu,
 191         .sync_sg_for_device             = dma_direct_sync_sg_for_device,
 192 };
 193 EXPORT_SYMBOL(dma_direct_ops);
 194
 195 /* Number of entries preallocated for DMA-API debugging */
 196 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 197
 198 static int __init dma_init(void)
 199 {
 200        dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 201
 202        return 0;
 203 }
 204 fs_initcall(dma_init);