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 u64 dma_direct_get_required_mask(struct device *dev)
 100 {
 101         u64 end, mask;
 102
 103         end = memblock_end_of_DRAM() + get_dma_offset(dev);
 104
 105         mask = 1ULL << (fls64(end) - 1);
 106         mask += mask - 1;
 107
 108         return mask;
 109 }
 110
 111 static inline dma_addr_t dma_direct_map_page(struct device *dev,
 112                                              struct page *page,
 113                                              unsigned long offset,
 114                                              size_t size,
 115                                              enum dma_data_direction dir,
 116                                              struct dma_attrs *attrs)
 117 {
 118         BUG_ON(dir == DMA_NONE);
 119         __dma_sync_page(page, offset, size, dir);
 120         return page_to_phys(page) + offset + get_dma_offset(dev);
 121 }
 122
 123 static inline void dma_direct_unmap_page(struct device *dev,
 124                                          dma_addr_t dma_address,
 125                                          size_t size,
 126                                          enum dma_data_direction direction,
 127                                          struct dma_attrs *attrs)
 128 {
 129 }
 130
 131 #ifdef CONFIG_NOT_COHERENT_CACHE
 132 static inline void dma_direct_sync_sg(struct device *dev,
 133                 struct scatterlist *sgl, int nents,
 134                 enum dma_data_direction direction)
 135 {
 136         struct scatterlist *sg;
 137         int i;
 138
 139         for_each_sg(sgl, sg, nents, i)
 140                 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
 141 }
 142
 143 static inline void dma_direct_sync_single(struct device *dev,
 144                                           dma_addr_t dma_handle, size_t size,
 145                                           enum dma_data_direction direction)
 146 {
 147         __dma_sync(bus_to_virt(dma_handle), size, direction);
 148 }
 149 #endif
 150
 151 struct dma_map_ops dma_direct_ops = {
 152         .alloc_coherent                 = dma_direct_alloc_coherent,
 153         .free_coherent                  = dma_direct_free_coherent,
 154         .map_sg                         = dma_direct_map_sg,
 155         .unmap_sg                       = dma_direct_unmap_sg,
 156         .dma_supported                  = dma_direct_dma_supported,
 157         .map_page                       = dma_direct_map_page,
 158         .unmap_page                     = dma_direct_unmap_page,
 159         .get_required_mask              = dma_direct_get_required_mask,
 160 #ifdef CONFIG_NOT_COHERENT_CACHE
 161         .sync_single_for_cpu            = dma_direct_sync_single,
 162         .sync_single_for_device         = dma_direct_sync_single,
 163         .sync_sg_for_cpu                = dma_direct_sync_sg,
 164         .sync_sg_for_device             = dma_direct_sync_sg,
 165 #endif
 166 };
 167 EXPORT_SYMBOL(dma_direct_ops);
 168
 169 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 170
 171 int dma_set_mask(struct device *dev, u64 dma_mask)
 172 {
 173         struct dma_map_ops *dma_ops = get_dma_ops(dev);
 174
 175         if (ppc_md.dma_set_mask)
 176                 return ppc_md.dma_set_mask(dev, dma_mask);
 177         if ((dma_ops != NULL) && (dma_ops->set_dma_mask != NULL))
 178                 return dma_ops->set_dma_mask(dev, dma_mask);
 179         if (!dev->dma_mask || !dma_supported(dev, dma_mask))
 180                 return -EIO;
 181         *dev->dma_mask = dma_mask;
 182         return 0;
 183 }
 184 EXPORT_SYMBOL(dma_set_mask);
 185
 186 u64 dma_get_required_mask(struct device *dev)
 187 {
 188         struct dma_map_ops *dma_ops = get_dma_ops(dev);
 189
 190         if (ppc_md.dma_get_required_mask)
 191                 return ppc_md.dma_get_required_mask(dev);
 192
 193         if (unlikely(dma_ops == NULL))
 194                 return 0;
 195
 196         if (dma_ops->get_required_mask)
 197                 return dma_ops->get_required_mask(dev);
 198
 199         return DMA_BIT_MASK(8 * sizeof(dma_addr_t));
 200 }
 201 EXPORT_SYMBOL_GPL(dma_get_required_mask);
 202
 203 static int __init dma_init(void)
 204 {
 205        dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 206
 207        return 0;
 208 }
 209 fs_initcall(dma_init);
 210
 211 int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
 212                       void *cpu_addr, dma_addr_t handle, size_t size)
 213 {
 214         unsigned long pfn;
 215
 216 #ifdef CONFIG_NOT_COHERENT_CACHE
 217         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 218         pfn = __dma_get_coherent_pfn((unsigned long)cpu_addr);
 219 #else
 220         pfn = page_to_pfn(virt_to_page(cpu_addr));
 221 #endif
 222         return remap_pfn_range(vma, vma->vm_start,
 223                                pfn + vma->vm_pgoff,
 224                                vma->vm_end - vma->vm_start,
 225                                vma->vm_page_prot);
 226 }
 227 EXPORT_SYMBOL_GPL(dma_mmap_coherent);