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 <linux/export.h>
  14 #include <asm/bug.h>
  15 #include <asm/abs_addr.h>
  16 #include <asm/machdep.h>
  17
  18 /*
  19  * Generic direct DMA implementation
  20  *
  21  * This implementation supports a per-device offset that can be applied if
  22  * the address at which memory is visible to devices is not 0. Platform code
  23  * can set archdata.dma_data to an unsigned long holding the offset. By
  24  * default the offset is PCI_DRAM_OFFSET.
  25  */
  26
  27
  28 void *dma_direct_alloc_coherent(struct device *dev, size_t size,
  29                                 dma_addr_t *dma_handle, gfp_t flag,
  30                                 struct dma_attrs *attrs)
  31 {
  32         void *ret;
  33 #ifdef CONFIG_NOT_COHERENT_CACHE
  34         ret = __dma_alloc_coherent(dev, size, dma_handle, flag);
  35         if (ret == NULL)
  36                 return NULL;
  37         *dma_handle += get_dma_offset(dev);
  38         return ret;
  39 #else
  40         struct page *page;
  41         int node = dev_to_node(dev);
  42
  43         /* ignore region specifiers */
  44         flag  &= ~(__GFP_HIGHMEM);
  45
  46         page = alloc_pages_node(node, flag, get_order(size));
  47         if (page == NULL)
  48                 return NULL;
  49         ret = page_address(page);
  50         memset(ret, 0, size);
  51         *dma_handle = virt_to_abs(ret) + get_dma_offset(dev);
  52
  53         return ret;
  54 #endif
  55 }
  56
  57 void dma_direct_free_coherent(struct device *dev, size_t size,
  58                               void *vaddr, dma_addr_t dma_handle,
  59                               struct dma_attrs *attrs)
  60 {
  61 #ifdef CONFIG_NOT_COHERENT_CACHE
  62         __dma_free_coherent(size, vaddr);
  63 #else
  64         free_pages((unsigned long)vaddr, get_order(size));
  65 #endif
  66 }
  67
  68 int dma_direct_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
  69                              void *cpu_addr, dma_addr_t handle, size_t size,
  70                              struct dma_attrs *attrs)
  71 {
  72         unsigned long pfn;
  73
  74 #ifdef CONFIG_NOT_COHERENT_CACHE
  75         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
  76         pfn = __dma_get_coherent_pfn((unsigned long)cpu_addr);
  77 #else
  78         pfn = page_to_pfn(virt_to_page(cpu_addr));
  79 #endif
  80         return remap_pfn_range(vma, vma->vm_start,
  81                                pfn + vma->vm_pgoff,
  82                                vma->vm_end - vma->vm_start,
  83                                vma->vm_page_prot);
  84 }
  85
  86 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
  87                              int nents, enum dma_data_direction direction,
  88                              struct dma_attrs *attrs)
  89 {
  90         struct scatterlist *sg;
  91         int i;
  92
  93         for_each_sg(sgl, sg, nents, i) {
  94                 sg->dma_address = sg_phys(sg) + get_dma_offset(dev);
  95                 sg->dma_length = sg->length;
  96                 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
  97         }
  98
  99         return nents;
 100 }
 101
 102 static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
 103                                 int nents, enum dma_data_direction direction,
 104                                 struct dma_attrs *attrs)
 105 {
 106 }
 107
 108 static int dma_direct_dma_supported(struct device *dev, u64 mask)
 109 {
 110 #ifdef CONFIG_PPC64
 111         /* Could be improved so platforms can set the limit in case
 112          * they have limited DMA windows
 113          */
 114         return mask >= get_dma_offset(dev) + (memblock_end_of_DRAM() - 1);
 115 #else
 116         return 1;
 117 #endif
 118 }
 119
 120 static u64 dma_direct_get_required_mask(struct device *dev)
 121 {
 122         u64 end, mask;
 123
 124         end = memblock_end_of_DRAM() + get_dma_offset(dev);
 125
 126         mask = 1ULL << (fls64(end) - 1);
 127         mask += mask - 1;
 128
 129         return mask;
 130 }
 131
 132 static inline dma_addr_t dma_direct_map_page(struct device *dev,
 133                                              struct page *page,
 134                                              unsigned long offset,
 135                                              size_t size,
 136                                              enum dma_data_direction dir,
 137                                              struct dma_attrs *attrs)
 138 {
 139         BUG_ON(dir == DMA_NONE);
 140         __dma_sync_page(page, offset, size, dir);
 141         return page_to_phys(page) + offset + get_dma_offset(dev);
 142 }
 143
 144 static inline void dma_direct_unmap_page(struct device *dev,
 145                                          dma_addr_t dma_address,
 146                                          size_t size,
 147                                          enum dma_data_direction direction,
 148                                          struct dma_attrs *attrs)
 149 {
 150 }
 151
 152 #ifdef CONFIG_NOT_COHERENT_CACHE
 153 static inline void dma_direct_sync_sg(struct device *dev,
 154                 struct scatterlist *sgl, int nents,
 155                 enum dma_data_direction direction)
 156 {
 157         struct scatterlist *sg;
 158         int i;
 159
 160         for_each_sg(sgl, sg, nents, i)
 161                 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
 162 }
 163
 164 static inline void dma_direct_sync_single(struct device *dev,
 165                                           dma_addr_t dma_handle, size_t size,
 166                                           enum dma_data_direction direction)
 167 {
 168         __dma_sync(bus_to_virt(dma_handle), size, direction);
 169 }
 170 #endif
 171
 172 struct dma_map_ops dma_direct_ops = {
 173         .alloc                          = dma_direct_alloc_coherent,
 174         .free                           = dma_direct_free_coherent,
 175         .mmap                           = dma_direct_mmap_coherent,
 176         .map_sg                         = dma_direct_map_sg,
 177         .unmap_sg                       = dma_direct_unmap_sg,
 178         .dma_supported                  = dma_direct_dma_supported,
 179         .map_page                       = dma_direct_map_page,
 180         .unmap_page                     = dma_direct_unmap_page,
 181         .get_required_mask              = dma_direct_get_required_mask,
 182 #ifdef CONFIG_NOT_COHERENT_CACHE
 183         .sync_single_for_cpu            = dma_direct_sync_single,
 184         .sync_single_for_device         = dma_direct_sync_single,
 185         .sync_sg_for_cpu                = dma_direct_sync_sg,
 186         .sync_sg_for_device             = dma_direct_sync_sg,
 187 #endif
 188 };
 189 EXPORT_SYMBOL(dma_direct_ops);
 190
 191 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 192
 193 int dma_set_mask(struct device *dev, u64 dma_mask)
 194 {
 195         struct dma_map_ops *dma_ops = get_dma_ops(dev);
 196
 197         if (ppc_md.dma_set_mask)
 198                 return ppc_md.dma_set_mask(dev, dma_mask);
 199         if ((dma_ops != NULL) && (dma_ops->set_dma_mask != NULL))
 200                 return dma_ops->set_dma_mask(dev, dma_mask);
 201         if (!dev->dma_mask || !dma_supported(dev, dma_mask))
 202                 return -EIO;
 203         *dev->dma_mask = dma_mask;
 204         return 0;
 205 }
 206 EXPORT_SYMBOL(dma_set_mask);
 207
 208 u64 dma_get_required_mask(struct device *dev)
 209 {
 210         struct dma_map_ops *dma_ops = get_dma_ops(dev);
 211
 212         if (ppc_md.dma_get_required_mask)
 213                 return ppc_md.dma_get_required_mask(dev);
 214
 215         if (unlikely(dma_ops == NULL))
 216                 return 0;
 217
 218         if (dma_ops->get_required_mask)
 219                 return dma_ops->get_required_mask(dev);
 220
 221         return DMA_BIT_MASK(8 * sizeof(dma_addr_t));
 222 }
 223 EXPORT_SYMBOL_GPL(dma_get_required_mask);
 224
 225 static int __init dma_init(void)
 226 {
 227        dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 228
 229        return 0;
 230 }
 231 fs_initcall(dma_init);
 232