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 <linux/pci.h>
  15 #include <asm/vio.h>
  16 #include <asm/bug.h>
  17 #include <asm/machdep.h>
  18
  19 /*
  20  * Generic direct DMA implementation
  21  *
  22  * This implementation supports a per-device offset that can be applied if
  23  * the address at which memory is visible to devices is not 0. Platform code
  24  * can set archdata.dma_data to an unsigned long holding the offset. By
  25  * default the offset is PCI_DRAM_OFFSET.
  26  */
  27
  28
  29 void *dma_direct_alloc_coherent(struct device *dev, size_t size,
  30                                 dma_addr_t *dma_handle, gfp_t flag,
  31                                 struct dma_attrs *attrs)
  32 {
  33         void *ret;
  34 #ifdef CONFIG_NOT_COHERENT_CACHE
  35         ret = __dma_alloc_coherent(dev, size, dma_handle, flag);
  36         if (ret == NULL)
  37                 return NULL;
  38         *dma_handle += get_dma_offset(dev);
  39         return ret;
  40 #else
  41         struct page *page;
  42         int node = dev_to_node(dev);
  43
  44         /* ignore region specifiers */
  45         flag  &= ~(__GFP_HIGHMEM);
  46
  47         page = alloc_pages_node(node, flag, get_order(size));
  48         if (page == NULL)
  49                 return NULL;
  50         ret = page_address(page);
  51         memset(ret, 0, size);
  52         *dma_handle = __pa(ret) + get_dma_offset(dev);
  53
  54         return ret;
  55 #endif
  56 }
  57
  58 void dma_direct_free_coherent(struct device *dev, size_t size,
  59                               void *vaddr, dma_addr_t dma_handle,
  60                               struct dma_attrs *attrs)
  61 {
  62 #ifdef CONFIG_NOT_COHERENT_CACHE
  63         __dma_free_coherent(size, vaddr);
  64 #else
  65         free_pages((unsigned long)vaddr, get_order(size));
  66 #endif
  67 }
  68
  69 int dma_direct_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
  70                              void *cpu_addr, dma_addr_t handle, size_t size,
  71                              struct dma_attrs *attrs)
  72 {
  73         unsigned long pfn;
  74
  75 #ifdef CONFIG_NOT_COHERENT_CACHE
  76         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
  77         pfn = __dma_get_coherent_pfn((unsigned long)cpu_addr);
  78 #else
  79         pfn = page_to_pfn(virt_to_page(cpu_addr));
  80 #endif
  81         return remap_pfn_range(vma, vma->vm_start,
  82                                pfn + vma->vm_pgoff,
  83                                vma->vm_end - vma->vm_start,
  84                                vma->vm_page_prot);
  85 }
  86
  87 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
  88                              int nents, enum dma_data_direction direction,
  89                              struct dma_attrs *attrs)
  90 {
  91         struct scatterlist *sg;
  92         int i;
  93
  94         for_each_sg(sgl, sg, nents, i) {
  95                 sg->dma_address = sg_phys(sg) + get_dma_offset(dev);
  96                 sg->dma_length = sg->length;
  97                 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
  98         }
  99
 100         return nents;
 101 }
 102
 103 static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
 104                                 int nents, enum dma_data_direction direction,
 105                                 struct dma_attrs *attrs)
 106 {
 107 }
 108
 109 static int dma_direct_dma_supported(struct device *dev, u64 mask)
 110 {
 111 #ifdef CONFIG_PPC64
 112         /* Could be improved so platforms can set the limit in case
 113          * they have limited DMA windows
 114          */
 115         return mask >= get_dma_offset(dev) + (memblock_end_of_DRAM() - 1);
 116 #else
 117         return 1;
 118 #endif
 119 }
 120
 121 static u64 dma_direct_get_required_mask(struct device *dev)
 122 {
 123         u64 end, mask;
 124
 125         end = memblock_end_of_DRAM() + get_dma_offset(dev);
 126
 127         mask = 1ULL << (fls64(end) - 1);
 128         mask += mask - 1;
 129
 130         return mask;
 131 }
 132
 133 static inline dma_addr_t dma_direct_map_page(struct device *dev,
 134                                              struct page *page,
 135                                              unsigned long offset,
 136                                              size_t size,
 137                                              enum dma_data_direction dir,
 138                                              struct dma_attrs *attrs)
 139 {
 140         BUG_ON(dir == DMA_NONE);
 141         __dma_sync_page(page, offset, size, dir);
 142         return page_to_phys(page) + offset + get_dma_offset(dev);
 143 }
 144
 145 static inline void dma_direct_unmap_page(struct device *dev,
 146                                          dma_addr_t dma_address,
 147                                          size_t size,
 148                                          enum dma_data_direction direction,
 149                                          struct dma_attrs *attrs)
 150 {
 151 }
 152
 153 #ifdef CONFIG_NOT_COHERENT_CACHE
 154 static inline void dma_direct_sync_sg(struct device *dev,
 155                 struct scatterlist *sgl, int nents,
 156                 enum dma_data_direction direction)
 157 {
 158         struct scatterlist *sg;
 159         int i;
 160
 161         for_each_sg(sgl, sg, nents, i)
 162                 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
 163 }
 164
 165 static inline void dma_direct_sync_single(struct device *dev,
 166                                           dma_addr_t dma_handle, size_t size,
 167                                           enum dma_data_direction direction)
 168 {
 169         __dma_sync(bus_to_virt(dma_handle), size, direction);
 170 }
 171 #endif
 172
 173 struct dma_map_ops dma_direct_ops = {
 174         .alloc                          = dma_direct_alloc_coherent,
 175         .free                           = dma_direct_free_coherent,
 176         .mmap                           = dma_direct_mmap_coherent,
 177         .map_sg                         = dma_direct_map_sg,
 178         .unmap_sg                       = dma_direct_unmap_sg,
 179         .dma_supported                  = dma_direct_dma_supported,
 180         .map_page                       = dma_direct_map_page,
 181         .unmap_page                     = dma_direct_unmap_page,
 182         .get_required_mask              = dma_direct_get_required_mask,
 183 #ifdef CONFIG_NOT_COHERENT_CACHE
 184         .sync_single_for_cpu            = dma_direct_sync_single,
 185         .sync_single_for_device         = dma_direct_sync_single,
 186         .sync_sg_for_cpu                = dma_direct_sync_sg,
 187         .sync_sg_for_device             = dma_direct_sync_sg,
 188 #endif
 189 };
 190 EXPORT_SYMBOL(dma_direct_ops);
 191
 192 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 193
 194 int __dma_set_mask(struct device *dev, u64 dma_mask)
 195 {
 196         struct dma_map_ops *dma_ops = get_dma_ops(dev);
 197
 198         if ((dma_ops != NULL) && (dma_ops->set_dma_mask != NULL))
 199                 return dma_ops->set_dma_mask(dev, dma_mask);
 200         if (!dev->dma_mask || !dma_supported(dev, dma_mask))
 201                 return -EIO;
 202         *dev->dma_mask = dma_mask;
 203         return 0;
 204 }
 205 int dma_set_mask(struct device *dev, u64 dma_mask)
 206 {
 207         if (ppc_md.dma_set_mask)
 208                 return ppc_md.dma_set_mask(dev, dma_mask);
 209         return __dma_set_mask(dev, dma_mask);
 210 }
 211 EXPORT_SYMBOL(dma_set_mask);
 212
 213 u64 dma_get_required_mask(struct device *dev)
 214 {
 215         struct dma_map_ops *dma_ops = get_dma_ops(dev);
 216
 217         if (ppc_md.dma_get_required_mask)
 218                 return ppc_md.dma_get_required_mask(dev);
 219
 220         if (unlikely(dma_ops == NULL))
 221                 return 0;
 222
 223         if (dma_ops->get_required_mask)
 224                 return dma_ops->get_required_mask(dev);
 225
 226         return DMA_BIT_MASK(8 * sizeof(dma_addr_t));
 227 }
 228 EXPORT_SYMBOL_GPL(dma_get_required_mask);
 229
 230 static int __init dma_init(void)
 231 {
 232         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 233 #ifdef CONFIG_PCI
 234         dma_debug_add_bus(&pci_bus_type);
 235 #endif
 236 #ifdef CONFIG_IBMVIO
 237         dma_debug_add_bus(&vio_bus_type);
 238 #endif
 239
 240        return 0;
 241 }
 242 fs_initcall(dma_init);
 243