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