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
  15 /*
  16  * Generic direct DMA implementation
  17  *
  18  * This implementation supports a per-device offset that can be applied if
  19  * the address at which memory is visible to devices is not 0. Platform code
  20  * can set archdata.dma_data to an unsigned long holding the offset. By
  21  * default the offset is PCI_DRAM_OFFSET.
  22  */
  23
  24 static unsigned long get_dma_direct_offset(struct device *dev)
  25 {
  26         if (likely(dev))
  27                 return (unsigned long)dev->archdata.dma_data;
  28
  29         return PCI_DRAM_OFFSET; /* FIXME Not sure if is correct */
  30 }
  31
  32 #define NOT_COHERENT_CACHE
  33
  34 static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
  35                                 dma_addr_t *dma_handle, gfp_t flag)
  36 {
  37 #ifdef NOT_COHERENT_CACHE
  38         return consistent_alloc(flag, size, dma_handle);
  39 #else
  40         void *ret;
  41         struct page *page;
  42         int node = dev_to_node(dev);
  43
  44         /* ignore region specifiers */
  45         flag  &= ~(__GFP_HIGHMEM);
  46
  47         page = alloc_pages_node(node, flag, get_order(size));
  48         if (page == NULL)
  49                 return NULL;
  50         ret = page_address(page);
  51         memset(ret, 0, size);
  52         *dma_handle = virt_to_phys(ret) + get_dma_direct_offset(dev);
  53
  54         return ret;
  55 #endif
  56 }
  57
  58 static void dma_direct_free_coherent(struct device *dev, size_t size,
  59                               void *vaddr, dma_addr_t dma_handle)
  60 {
  61 #ifdef NOT_COHERENT_CACHE
  62         consistent_free(size, vaddr);
  63 #else
  64         free_pages((unsigned long)vaddr, get_order(size));
  65 #endif
  66 }
  67
  68 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
  69                              int nents, enum dma_data_direction direction,
  70                              struct dma_attrs *attrs)
  71 {
  72         struct scatterlist *sg;
  73         int i;
  74
  75         /* FIXME this part of code is untested */
  76         for_each_sg(sgl, sg, nents, i) {
  77                 sg->dma_address = sg_phys(sg) + get_dma_direct_offset(dev);
  78                 __dma_sync(page_to_phys(sg_page(sg)) + sg->offset,
  79                                                         sg->length, direction);
  80         }
  81
  82         return nents;
  83 }
  84
  85 static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
  86                                 int nents, enum dma_data_direction direction,
  87                                 struct dma_attrs *attrs)
  88 {
  89 }
  90
  91 static int dma_direct_dma_supported(struct device *dev, u64 mask)
  92 {
  93         return 1;
  94 }
  95
  96 static inline dma_addr_t dma_direct_map_page(struct device *dev,
  97                                              struct page *page,
  98                                              unsigned long offset,
  99                                              size_t size,
 100                                              enum dma_data_direction direction,
 101                                              struct dma_attrs *attrs)
 102 {
 103         __dma_sync(page_to_phys(page) + offset, size, direction);
 104         return page_to_phys(page) + offset + get_dma_direct_offset(dev);
 105 }
 106
 107 static inline void dma_direct_unmap_page(struct device *dev,
 108                                          dma_addr_t dma_address,
 109                                          size_t size,
 110                                          enum dma_data_direction direction,
 111                                          struct dma_attrs *attrs)
 112 {
 113 /* There is not necessary to do cache cleanup
 114  *
 115  * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
 116  * dma_address is physical address
 117  */
 118         __dma_sync(dma_address, size, direction);
 119 }
 120
 121 static inline void
 122 dma_direct_sync_single_for_cpu(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 flush the cache as the memory segment
 128          * is given to the CPU
 129          */
 130
 131         if (direction == DMA_FROM_DEVICE)
 132                 __dma_sync(dma_handle, size, direction);
 133 }
 134
 135 static inline void
 136 dma_direct_sync_single_for_device(struct device *dev,
 137                                   dma_addr_t dma_handle, size_t size,
 138                                   enum dma_data_direction direction)
 139 {
 140         /*
 141          * It's pointless to invalidate the cache if the device isn't
 142          * supposed to write to the relevant region
 143          */
 144
 145         if (direction == DMA_TO_DEVICE)
 146                 __dma_sync(dma_handle, size, direction);
 147 }
 148
 149 static inline void
 150 dma_direct_sync_sg_for_cpu(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_FROM_DEVICE)
 159                 for_each_sg(sgl, sg, nents, i)
 160                         __dma_sync(sg->dma_address, sg->length, direction);
 161 }
 162
 163 static inline void
 164 dma_direct_sync_sg_for_device(struct device *dev,
 165                               struct scatterlist *sgl, int nents,
 166                               enum dma_data_direction direction)
 167 {
 168         struct scatterlist *sg;
 169         int i;
 170
 171         /* FIXME this part of code is untested */
 172         if (direction == DMA_TO_DEVICE)
 173                 for_each_sg(sgl, sg, nents, i)
 174                         __dma_sync(sg->dma_address, sg->length, direction);
 175 }
 176
 177 struct dma_map_ops dma_direct_ops = {
 178         .alloc_coherent = dma_direct_alloc_coherent,
 179         .free_coherent  = dma_direct_free_coherent,
 180         .map_sg         = dma_direct_map_sg,
 181         .unmap_sg       = dma_direct_unmap_sg,
 182         .dma_supported  = dma_direct_dma_supported,
 183         .map_page       = dma_direct_map_page,
 184         .unmap_page     = dma_direct_unmap_page,
 185         .sync_single_for_cpu            = dma_direct_sync_single_for_cpu,
 186         .sync_single_for_device         = dma_direct_sync_single_for_device,
 187         .sync_sg_for_cpu                = dma_direct_sync_sg_for_cpu,
 188         .sync_sg_for_device             = dma_direct_sync_sg_for_device,
 189 };
 190 EXPORT_SYMBOL(dma_direct_ops);
 191
 192 /* Number of entries preallocated for DMA-API debugging */
 193 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 194
 195 static int __init dma_init(void)
 196 {
 197        dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 198
 199        return 0;
 200 }
 201 fs_initcall(dma_init);