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/dma-debug.h>
  12 #include <asm/bug.h>
  13 #include <asm/cacheflush.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 static inline void __dma_sync_page(unsigned long paddr, unsigned long offset,
  24                                 size_t size, enum dma_data_direction direction)
  25 {
  26         switch (direction) {
  27         case DMA_TO_DEVICE:
  28                 flush_dcache_range(paddr + offset, paddr + offset + size);
  29                 break;
  30         case DMA_FROM_DEVICE:
  31                 invalidate_dcache_range(paddr + offset, paddr + offset + size);
  32                 break;
  33         default:
  34                 BUG();
  35         }
  36 }
  37
  38 static unsigned long get_dma_direct_offset(struct device *dev)
  39 {
  40         if (dev)
  41                 return (unsigned long)dev->archdata.dma_data;
  42
  43         return PCI_DRAM_OFFSET; /* FIXME Not sure if is correct */
  44 }
  45
  46 #define NOT_COHERENT_CACHE
  47
  48 static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
  49                                 dma_addr_t *dma_handle, gfp_t flag)
  50 {
  51 #ifdef NOT_COHERENT_CACHE
  52         return consistent_alloc(flag, size, dma_handle);
  53 #else
  54         void *ret;
  55         struct page *page;
  56         int node = dev_to_node(dev);
  57
  58         /* ignore region specifiers */
  59         flag  &= ~(__GFP_HIGHMEM);
  60
  61         page = alloc_pages_node(node, flag, get_order(size));
  62         if (page == NULL)
  63                 return NULL;
  64         ret = page_address(page);
  65         memset(ret, 0, size);
  66         *dma_handle = virt_to_phys(ret) + get_dma_direct_offset(dev);
  67
  68         return ret;
  69 #endif
  70 }
  71
  72 static void dma_direct_free_coherent(struct device *dev, size_t size,
  73                               void *vaddr, dma_addr_t dma_handle)
  74 {
  75 #ifdef NOT_COHERENT_CACHE
  76         consistent_free(vaddr);
  77 #else
  78         free_pages((unsigned long)vaddr, get_order(size));
  79 #endif
  80 }
  81
  82 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
  83                              int nents, enum dma_data_direction direction,
  84                              struct dma_attrs *attrs)
  85 {
  86         struct scatterlist *sg;
  87         int i;
  88
  89         /* FIXME this part of code is untested */
  90         for_each_sg(sgl, sg, nents, i) {
  91                 sg->dma_address = sg_phys(sg) + get_dma_direct_offset(dev);
  92                 sg->dma_length = sg->length;
  93                 __dma_sync_page(page_to_phys(sg_page(sg)), sg->offset,
  94                                                         sg->length, direction);
  95         }
  96
  97         return nents;
  98 }
  99
 100 static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
 101                                 int nents, enum dma_data_direction direction,
 102                                 struct dma_attrs *attrs)
 103 {
 104 }
 105
 106 static int dma_direct_dma_supported(struct device *dev, u64 mask)
 107 {
 108         return 1;
 109 }
 110
 111 static inline dma_addr_t dma_direct_map_page(struct device *dev,
 112                                              struct page *page,
 113                                              unsigned long offset,
 114                                              size_t size,
 115                                              enum dma_data_direction direction,
 116                                              struct dma_attrs *attrs)
 117 {
 118         __dma_sync_page(page_to_phys(page), offset, size, direction);
 119         return page_to_phys(page) + offset + get_dma_direct_offset(dev);
 120 }
 121
 122 static inline void dma_direct_unmap_page(struct device *dev,
 123                                          dma_addr_t dma_address,
 124                                          size_t size,
 125                                          enum dma_data_direction direction,
 126                                          struct dma_attrs *attrs)
 127 {
 128 /* There is not necessary to do cache cleanup
 129  *
 130  * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
 131  * dma_address is physical address
 132  */
 133         __dma_sync_page(dma_address, 0 , size, direction);
 134 }
 135
 136 struct dma_map_ops dma_direct_ops = {
 137         .alloc_coherent = dma_direct_alloc_coherent,
 138         .free_coherent  = dma_direct_free_coherent,
 139         .map_sg         = dma_direct_map_sg,
 140         .unmap_sg       = dma_direct_unmap_sg,
 141         .dma_supported  = dma_direct_dma_supported,
 142         .map_page       = dma_direct_map_page,
 143         .unmap_page     = dma_direct_unmap_page,
 144 };
 145 EXPORT_SYMBOL(dma_direct_ops);
 146
 147 /* Number of entries preallocated for DMA-API debugging */
 148 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 149
 150 static int __init dma_init(void)
 151 {
 152        dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 153
 154        return 0;
 155 }
 156 fs_initcall(dma_init);