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