arch/powerpc/kernel/dma.c

   1 /*
   2  * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
   3  *
   4  * Provide default implementations of the DMA mapping callbacks for
   5  * directly mapped busses.
   6  */
   7
   8 #include <linux/device.h>
   9 #include <linux/dma-mapping.h>
  10 #include <linux/dma-debug.h>
  11 #include <linux/lmb.h>
  12 #include <asm/bug.h>
  13 #include <asm/abs_addr.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 unsigned long get_dma_direct_offset(struct device *dev)
  25 {
  26         if (dev)
  27                 return (unsigned long)dev->archdata.dma_data;
  28
  29         return PCI_DRAM_OFFSET;
  30 }
  31
  32 void *dma_direct_alloc_coherent(struct device *dev, size_t size,
  33                                 dma_addr_t *dma_handle, gfp_t flag)
  34 {
  35         void *ret;
  36 #ifdef CONFIG_NOT_COHERENT_CACHE
  37         ret = __dma_alloc_coherent(dev, size, dma_handle, flag);
  38         if (ret == NULL)
  39                 return NULL;
  40         *dma_handle += get_dma_direct_offset(dev);
  41         return ret;
  42 #else
  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_abs(ret) + get_dma_direct_offset(dev);
  55
  56         return ret;
  57 #endif
  58 }
  59
  60 void dma_direct_free_coherent(struct device *dev, size_t size,
  61                               void *vaddr, dma_addr_t dma_handle)
  62 {
  63 #ifdef CONFIG_NOT_COHERENT_CACHE
  64         __dma_free_coherent(size, vaddr);
  65 #else
  66         free_pages((unsigned long)vaddr, get_order(size));
  67 #endif
  68 }
  69
  70 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
  71                              int nents, enum dma_data_direction direction,
  72                              struct dma_attrs *attrs)
  73 {
  74         struct scatterlist *sg;
  75         int i;
  76
  77         for_each_sg(sgl, sg, nents, i) {
  78                 sg->dma_address = sg_phys(sg) + get_dma_direct_offset(dev);
  79                 sg->dma_length = sg->length;
  80                 __dma_sync_page(sg_page(sg), sg->offset, 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 #ifdef CONFIG_PPC64
  95         /* Could be improved so platforms can set the limit in case
  96          * they have limited DMA windows
  97          */
  98         return mask >= (lmb_end_of_DRAM() - 1);
  99 #else
 100         return 1;
 101 #endif
 102 }
 103
 104 static inline dma_addr_t dma_direct_map_page(struct device *dev,
 105                                              struct page *page,
 106                                              unsigned long offset,
 107                                              size_t size,
 108                                              enum dma_data_direction dir,
 109                                              struct dma_attrs *attrs)
 110 {
 111         BUG_ON(dir == DMA_NONE);
 112         __dma_sync_page(page, offset, size, dir);
 113         return page_to_phys(page) + offset + get_dma_direct_offset(dev);
 114 }
 115
 116 static inline void dma_direct_unmap_page(struct device *dev,
 117                                          dma_addr_t dma_address,
 118                                          size_t size,
 119                                          enum dma_data_direction direction,
 120                                          struct dma_attrs *attrs)
 121 {
 122 }
 123
 124 #ifdef CONFIG_NOT_COHERENT_CACHE
 125 static inline void dma_direct_sync_sg(struct device *dev,
 126                 struct scatterlist *sgl, int nents,
 127                 enum dma_data_direction direction)
 128 {
 129         struct scatterlist *sg;
 130         int i;
 131
 132         for_each_sg(sgl, sg, nents, i)
 133                 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
 134 }
 135
 136 static inline void dma_direct_sync_single_range(struct device *dev,
 137                 dma_addr_t dma_handle, unsigned long offset, size_t size,
 138                 enum dma_data_direction direction)
 139 {
 140         __dma_sync(bus_to_virt(dma_handle+offset), size, direction);
 141 }
 142 #endif
 143
 144 struct dma_map_ops dma_direct_ops = {
 145         .alloc_coherent = dma_direct_alloc_coherent,
 146         .free_coherent  = dma_direct_free_coherent,
 147         .map_sg         = dma_direct_map_sg,
 148         .unmap_sg       = dma_direct_unmap_sg,
 149         .dma_supported  = dma_direct_dma_supported,
 150         .map_page       = dma_direct_map_page,
 151         .unmap_page     = dma_direct_unmap_page,
 152 #ifdef CONFIG_NOT_COHERENT_CACHE
 153         .sync_single_range_for_cpu      = dma_direct_sync_single_range,
 154         .sync_single_range_for_device   = dma_direct_sync_single_range,
 155         .sync_sg_for_cpu                = dma_direct_sync_sg,
 156         .sync_sg_for_device             = dma_direct_sync_sg,
 157 #endif
 158 };
 159 EXPORT_SYMBOL(dma_direct_ops);
 160
 161 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 162
 163 static int __init dma_init(void)
 164 {
 165        dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 166
 167        return 0;
 168 }
 169 fs_initcall(dma_init);