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