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
  25 void *dma_direct_alloc_coherent(struct device *dev, size_t size,
  26                                 dma_addr_t *dma_handle, gfp_t flag)
  27 {
  28         void *ret;
  29 #ifdef CONFIG_NOT_COHERENT_CACHE
  30         ret = __dma_alloc_coherent(dev, size, dma_handle, flag);
  31         if (ret == NULL)
  32                 return NULL;
  33         *dma_handle += get_dma_offset(dev);
  34         return ret;
  35 #else
  36         struct page *page;
  37         int node = dev_to_node(dev);
  38
  39         /* ignore region specifiers */
  40         flag  &= ~(__GFP_HIGHMEM);
  41
  42         page = alloc_pages_node(node, flag, get_order(size));
  43         if (page == NULL)
  44                 return NULL;
  45         ret = page_address(page);
  46         memset(ret, 0, size);
  47         *dma_handle = virt_to_abs(ret) + get_dma_offset(dev);
  48
  49         return ret;
  50 #endif
  51 }
  52
  53 void dma_direct_free_coherent(struct device *dev, size_t size,
  54                               void *vaddr, dma_addr_t dma_handle)
  55 {
  56 #ifdef CONFIG_NOT_COHERENT_CACHE
  57         __dma_free_coherent(size, vaddr);
  58 #else
  59         free_pages((unsigned long)vaddr, get_order(size));
  60 #endif
  61 }
  62
  63 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
  64                              int nents, enum dma_data_direction direction,
  65                              struct dma_attrs *attrs)
  66 {
  67         struct scatterlist *sg;
  68         int i;
  69
  70         for_each_sg(sgl, sg, nents, i) {
  71                 sg->dma_address = sg_phys(sg) + get_dma_offset(dev);
  72                 sg->dma_length = sg->length;
  73                 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
  74         }
  75
  76         return nents;
  77 }
  78
  79 static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
  80                                 int nents, enum dma_data_direction direction,
  81                                 struct dma_attrs *attrs)
  82 {
  83 }
  84
  85 static int dma_direct_dma_supported(struct device *dev, u64 mask)
  86 {
  87 #ifdef CONFIG_PPC64
  88         /* Could be improved so platforms can set the limit in case
  89          * they have limited DMA windows
  90          */
  91         return mask >= (lmb_end_of_DRAM() - 1);
  92 #else
  93         return 1;
  94 #endif
  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 dir,
 102                                              struct dma_attrs *attrs)
 103 {
 104         BUG_ON(dir == DMA_NONE);
 105         __dma_sync_page(page, offset, size, dir);
 106         return page_to_phys(page) + offset + get_dma_offset(dev);
 107 }
 108
 109 static inline void dma_direct_unmap_page(struct device *dev,
 110                                          dma_addr_t dma_address,
 111                                          size_t size,
 112                                          enum dma_data_direction direction,
 113                                          struct dma_attrs *attrs)
 114 {
 115 }
 116
 117 #ifdef CONFIG_NOT_COHERENT_CACHE
 118 static inline void dma_direct_sync_sg(struct device *dev,
 119                 struct scatterlist *sgl, int nents,
 120                 enum dma_data_direction direction)
 121 {
 122         struct scatterlist *sg;
 123         int i;
 124
 125         for_each_sg(sgl, sg, nents, i)
 126                 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
 127 }
 128
 129 static inline void dma_direct_sync_single_range(struct device *dev,
 130                 dma_addr_t dma_handle, unsigned long offset, size_t size,
 131                 enum dma_data_direction direction)
 132 {
 133         __dma_sync(bus_to_virt(dma_handle+offset), size, direction);
 134 }
 135 #endif
 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 #ifdef CONFIG_NOT_COHERENT_CACHE
 146         .sync_single_range_for_cpu      = dma_direct_sync_single_range,
 147         .sync_single_range_for_device   = dma_direct_sync_single_range,
 148         .sync_sg_for_cpu                = dma_direct_sync_sg,
 149         .sync_sg_for_device             = dma_direct_sync_sg,
 150 #endif
 151 };
 152 EXPORT_SYMBOL(dma_direct_ops);
 153
 154 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 155
 156 static int __init dma_init(void)
 157 {
 158        dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 159
 160        return 0;
 161 }
 162 fs_initcall(dma_init);