arch/microblaze/kernel/dma.c

   1 /*
   2  * Copyright (C) 2009-2010 PetaLogix
   3  * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
   4  *
   5  * Provide default implementations of the DMA mapping callbacks for
   6  * directly mapped busses.
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/dma-mapping.h>
  11 #include <linux/gfp.h>
  12 #include <linux/dma-debug.h>
  13 #include <linux/export.h>
  14 #include <linux/bug.h>
  15
  16 #define NOT_COHERENT_CACHE
  17
  18 static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
  19                                        dma_addr_t *dma_handle, gfp_t flag,
  20                                        struct dma_attrs *attrs)
  21 {
  22 #ifdef NOT_COHERENT_CACHE
  23         return consistent_alloc(flag, size, dma_handle);
  24 #else
  25         void *ret;
  26         struct page *page;
  27         int node = dev_to_node(dev);
  28
  29         /* ignore region specifiers */
  30         flag  &= ~(__GFP_HIGHMEM);
  31
  32         page = alloc_pages_node(node, flag, get_order(size));
  33         if (page == NULL)
  34                 return NULL;
  35         ret = page_address(page);
  36         memset(ret, 0, size);
  37         *dma_handle = virt_to_phys(ret);
  38
  39         return ret;
  40 #endif
  41 }
  42
  43 static void dma_direct_free_coherent(struct device *dev, size_t size,
  44                                      void *vaddr, dma_addr_t dma_handle,
  45                                      struct dma_attrs *attrs)
  46 {
  47 #ifdef NOT_COHERENT_CACHE
  48         consistent_free(size, vaddr);
  49 #else
  50         free_pages((unsigned long)vaddr, get_order(size));
  51 #endif
  52 }
  53
  54 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
  55                              int nents, enum dma_data_direction direction,
  56                              struct dma_attrs *attrs)
  57 {
  58         struct scatterlist *sg;
  59         int i;
  60
  61         /* FIXME this part of code is untested */
  62         for_each_sg(sgl, sg, nents, i) {
  63                 sg->dma_address = sg_phys(sg);
  64                 __dma_sync(sg_phys(sg), sg->length, direction);
  65         }
  66
  67         return nents;
  68 }
  69
  70 static int dma_direct_dma_supported(struct device *dev, u64 mask)
  71 {
  72         return 1;
  73 }
  74
  75 static inline dma_addr_t dma_direct_map_page(struct device *dev,
  76                                              struct page *page,
  77                                              unsigned long offset,
  78                                              size_t size,
  79                                              enum dma_data_direction direction,
  80                                              struct dma_attrs *attrs)
  81 {
  82         __dma_sync(page_to_phys(page) + offset, size, direction);
  83         return page_to_phys(page) + offset;
  84 }
  85
  86 static inline void dma_direct_unmap_page(struct device *dev,
  87                                          dma_addr_t dma_address,
  88                                          size_t size,
  89                                          enum dma_data_direction direction,
  90                                          struct dma_attrs *attrs)
  91 {
  92 /* There is not necessary to do cache cleanup
  93  *
  94  * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
  95  * dma_address is physical address
  96  */
  97         __dma_sync(dma_address, size, direction);
  98 }
  99
 100 static inline void
 101 dma_direct_sync_single_for_cpu(struct device *dev,
 102                                dma_addr_t dma_handle, size_t size,
 103                                enum dma_data_direction direction)
 104 {
 105         /*
 106          * It's pointless to flush the cache as the memory segment
 107          * is given to the CPU
 108          */
 109
 110         if (direction == DMA_FROM_DEVICE)
 111                 __dma_sync(dma_handle, size, direction);
 112 }
 113
 114 static inline void
 115 dma_direct_sync_single_for_device(struct device *dev,
 116                                   dma_addr_t dma_handle, size_t size,
 117                                   enum dma_data_direction direction)
 118 {
 119         /*
 120          * It's pointless to invalidate the cache if the device isn't
 121          * supposed to write to the relevant region
 122          */
 123
 124         if (direction == DMA_TO_DEVICE)
 125                 __dma_sync(dma_handle, size, direction);
 126 }
 127
 128 static inline void
 129 dma_direct_sync_sg_for_cpu(struct device *dev,
 130                            struct scatterlist *sgl, int nents,
 131                            enum dma_data_direction direction)
 132 {
 133         struct scatterlist *sg;
 134         int i;
 135
 136         /* FIXME this part of code is untested */
 137         if (direction == DMA_FROM_DEVICE)
 138                 for_each_sg(sgl, sg, nents, i)
 139                         __dma_sync(sg->dma_address, sg->length, direction);
 140 }
 141
 142 static inline void
 143 dma_direct_sync_sg_for_device(struct device *dev,
 144                               struct scatterlist *sgl, int nents,
 145                               enum dma_data_direction direction)
 146 {
 147         struct scatterlist *sg;
 148         int i;
 149
 150         /* FIXME this part of code is untested */
 151         if (direction == DMA_TO_DEVICE)
 152                 for_each_sg(sgl, sg, nents, i)
 153                         __dma_sync(sg->dma_address, sg->length, direction);
 154 }
 155
 156 static
 157 int dma_direct_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
 158                              void *cpu_addr, dma_addr_t handle, size_t size,
 159                              struct dma_attrs *attrs)
 160 {
 161 #ifdef CONFIG_MMU
 162         unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 163         unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 164         unsigned long off = vma->vm_pgoff;
 165         unsigned long pfn;
 166
 167         if (off >= count || user_count > (count - off))
 168                 return -ENXIO;
 169
 170 #ifdef NOT_COHERENT_CACHE
 171         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 172         pfn = consistent_virt_to_pfn(cpu_addr);
 173 #else
 174         pfn = virt_to_pfn(cpu_addr);
 175 #endif
 176         return remap_pfn_range(vma, vma->vm_start, pfn + off,
 177                                vma->vm_end - vma->vm_start, vma->vm_page_prot);
 178 #else
 179         return -ENXIO;
 180 #endif
 181 }
 182
 183 struct dma_map_ops dma_direct_ops = {
 184         .alloc          = dma_direct_alloc_coherent,
 185         .free           = dma_direct_free_coherent,
 186         .mmap           = dma_direct_mmap_coherent,
 187         .map_sg         = dma_direct_map_sg,
 188         .dma_supported  = dma_direct_dma_supported,
 189         .map_page       = dma_direct_map_page,
 190         .unmap_page     = dma_direct_unmap_page,
 191         .sync_single_for_cpu            = dma_direct_sync_single_for_cpu,
 192         .sync_single_for_device         = dma_direct_sync_single_for_device,
 193         .sync_sg_for_cpu                = dma_direct_sync_sg_for_cpu,
 194         .sync_sg_for_device             = dma_direct_sync_sg_for_device,
 195 };
 196 EXPORT_SYMBOL(dma_direct_ops);
 197
 198 /* Number of entries preallocated for DMA-API debugging */
 199 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 200
 201 static int __init dma_init(void)
 202 {
 203         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 204
 205         return 0;
 206 }
 207 fs_initcall(dma_init);