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/gfp.h>
  12 #include <linux/memblock.h>
  13 #include <asm/bug.h>
  14 #include <asm/abs_addr.h>
  15 #include <asm/machdep.h>
  16
  17 /*
  18  * Generic direct DMA implementation
  19  *
  20  * This implementation supports a per-device offset that can be applied if
  21  * the address at which memory is visible to devices is not 0. Platform code
  22  * can set archdata.dma_data to an unsigned long holding the offset. By
  23  * default the offset is PCI_DRAM_OFFSET.
  24  */
  25
  26
  27 void *dma_direct_alloc_coherent(struct device *dev, size_t size,
  28                                 dma_addr_t *dma_handle, gfp_t flag)
  29 {
  30         void *ret;
  31 #ifdef CONFIG_NOT_COHERENT_CACHE
  32         ret = __dma_alloc_coherent(dev, size, dma_handle, flag);
  33         if (ret == NULL)
  34                 return NULL;
  35         *dma_handle += get_dma_offset(dev);
  36         return ret;
  37 #else
  38         struct page *page;
  39         int node = dev_to_node(dev);
  40
  41         /* ignore region specifiers */
  42         flag  &= ~(__GFP_HIGHMEM);
  43
  44         page = alloc_pages_node(node, flag, get_order(size));
  45         if (page == NULL)
  46                 return NULL;
  47         ret = page_address(page);
  48         memset(ret, 0, size);
  49         *dma_handle = virt_to_abs(ret) + get_dma_offset(dev);
  50
  51         return ret;
  52 #endif
  53 }
  54
  55 void dma_direct_free_coherent(struct device *dev, size_t size,
  56                               void *vaddr, dma_addr_t dma_handle)
  57 {
  58 #ifdef CONFIG_NOT_COHERENT_CACHE
  59         __dma_free_coherent(size, vaddr);
  60 #else
  61         free_pages((unsigned long)vaddr, get_order(size));
  62 #endif
  63 }
  64
  65 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
  66                              int nents, enum dma_data_direction direction,
  67                              struct dma_attrs *attrs)
  68 {
  69         struct scatterlist *sg;
  70         int i;
  71
  72         for_each_sg(sgl, sg, nents, i) {
  73                 sg->dma_address = sg_phys(sg) + get_dma_offset(dev);
  74                 sg->dma_length = sg->length;
  75                 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
  76         }
  77
  78         return nents;
  79 }
  80
  81 static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
  82                                 int nents, enum dma_data_direction direction,
  83                                 struct dma_attrs *attrs)
  84 {
  85 }
  86
  87 static int dma_direct_dma_supported(struct device *dev, u64 mask)
  88 {
  89 #ifdef CONFIG_PPC64
  90         /* Could be improved so platforms can set the limit in case
  91          * they have limited DMA windows
  92          */
  93         return mask >= get_dma_offset(dev) + (memblock_end_of_DRAM() - 1);
  94 #else
  95         return 1;
  96 #endif
  97 }
  98
  99 static inline dma_addr_t dma_direct_map_page(struct device *dev,
 100                                              struct page *page,
 101                                              unsigned long offset,
 102                                              size_t size,
 103                                              enum dma_data_direction dir,
 104                                              struct dma_attrs *attrs)
 105 {
 106         BUG_ON(dir == DMA_NONE);
 107         __dma_sync_page(page, offset, size, dir);
 108         return page_to_phys(page) + offset + get_dma_offset(dev);
 109 }
 110
 111 static inline void dma_direct_unmap_page(struct device *dev,
 112                                          dma_addr_t dma_address,
 113                                          size_t size,
 114                                          enum dma_data_direction direction,
 115                                          struct dma_attrs *attrs)
 116 {
 117 }
 118
 119 #ifdef CONFIG_NOT_COHERENT_CACHE
 120 static inline void dma_direct_sync_sg(struct device *dev,
 121                 struct scatterlist *sgl, int nents,
 122                 enum dma_data_direction direction)
 123 {
 124         struct scatterlist *sg;
 125         int i;
 126
 127         for_each_sg(sgl, sg, nents, i)
 128                 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
 129 }
 130
 131 static inline void dma_direct_sync_single(struct device *dev,
 132                                           dma_addr_t dma_handle, size_t size,
 133                                           enum dma_data_direction direction)
 134 {
 135         __dma_sync(bus_to_virt(dma_handle), size, direction);
 136 }
 137 #endif
 138
 139 struct dma_map_ops dma_direct_ops = {
 140         .alloc_coherent = dma_direct_alloc_coherent,
 141         .free_coherent  = dma_direct_free_coherent,
 142         .map_sg         = dma_direct_map_sg,
 143         .unmap_sg       = dma_direct_unmap_sg,
 144         .dma_supported  = dma_direct_dma_supported,
 145         .map_page       = dma_direct_map_page,
 146         .unmap_page     = dma_direct_unmap_page,
 147 #ifdef CONFIG_NOT_COHERENT_CACHE
 148         .sync_single_for_cpu            = dma_direct_sync_single,
 149         .sync_single_for_device         = dma_direct_sync_single,
 150         .sync_sg_for_cpu                = dma_direct_sync_sg,
 151         .sync_sg_for_device             = dma_direct_sync_sg,
 152 #endif
 153 };
 154 EXPORT_SYMBOL(dma_direct_ops);
 155
 156 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 157
 158 int dma_set_mask(struct device *dev, u64 dma_mask)
 159 {
 160         struct dma_map_ops *dma_ops = get_dma_ops(dev);
 161
 162         if (ppc_md.dma_set_mask)
 163                 return ppc_md.dma_set_mask(dev, dma_mask);
 164         if (unlikely(dma_ops == NULL))
 165                 return -EIO;
 166         if (dma_ops->set_dma_mask != NULL)
 167                 return dma_ops->set_dma_mask(dev, dma_mask);
 168         if (!dev->dma_mask || !dma_supported(dev, dma_mask))
 169                 return -EIO;
 170         *dev->dma_mask = dma_mask;
 171         return 0;
 172 }
 173 EXPORT_SYMBOL(dma_set_mask);
 174
 175 static int __init dma_init(void)
 176 {
 177        dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 178
 179        return 0;
 180 }
 181 fs_initcall(dma_init);