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                                        unsigned long 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                                      unsigned long 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                              unsigned long 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
  65                 if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
  66                         continue;
  67
  68                 __dma_sync(sg_phys(sg), sg->length, direction);
  69         }
  70
  71         return nents;
  72 }
  73
  74 static int dma_direct_dma_supported(struct device *dev, u64 mask)
  75 {
  76         return 1;
  77 }
  78
  79 static inline dma_addr_t dma_direct_map_page(struct device *dev,
  80                                              struct page *page,
  81                                              unsigned long offset,
  82                                              size_t size,
  83                                              enum dma_data_direction direction,
  84                                              unsigned long attrs)
  85 {
  86         if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
  87                 __dma_sync(page_to_phys(page) + offset, size, direction);
  88         return page_to_phys(page) + offset;
  89 }
  90
  91 static inline void dma_direct_unmap_page(struct device *dev,
  92                                          dma_addr_t dma_address,
  93                                          size_t size,
  94                                          enum dma_data_direction direction,
  95                                          unsigned long attrs)
  96 {
  97 /* There is not necessary to do cache cleanup
  98  *
  99  * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
 100  * dma_address is physical address
 101  */
 102         if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 103                 __dma_sync(dma_address, size, direction);
 104 }
 105
 106 static inline void
 107 dma_direct_sync_single_for_cpu(struct device *dev,
 108                                dma_addr_t dma_handle, size_t size,
 109                                enum dma_data_direction direction)
 110 {
 111         /*
 112          * It's pointless to flush the cache as the memory segment
 113          * is given to the CPU
 114          */
 115
 116         if (direction == DMA_FROM_DEVICE)
 117                 __dma_sync(dma_handle, size, direction);
 118 }
 119
 120 static inline void
 121 dma_direct_sync_single_for_device(struct device *dev,
 122                                   dma_addr_t dma_handle, size_t size,
 123                                   enum dma_data_direction direction)
 124 {
 125         /*
 126          * It's pointless to invalidate the cache if the device isn't
 127          * supposed to write to the relevant region
 128          */
 129
 130         if (direction == DMA_TO_DEVICE)
 131                 __dma_sync(dma_handle, size, direction);
 132 }
 133
 134 static inline void
 135 dma_direct_sync_sg_for_cpu(struct device *dev,
 136                            struct scatterlist *sgl, int nents,
 137                            enum dma_data_direction direction)
 138 {
 139         struct scatterlist *sg;
 140         int i;
 141
 142         /* FIXME this part of code is untested */
 143         if (direction == DMA_FROM_DEVICE)
 144                 for_each_sg(sgl, sg, nents, i)
 145                         __dma_sync(sg->dma_address, sg->length, direction);
 146 }
 147
 148 static inline void
 149 dma_direct_sync_sg_for_device(struct device *dev,
 150                               struct scatterlist *sgl, int nents,
 151                               enum dma_data_direction direction)
 152 {
 153         struct scatterlist *sg;
 154         int i;
 155
 156         /* FIXME this part of code is untested */
 157         if (direction == DMA_TO_DEVICE)
 158                 for_each_sg(sgl, sg, nents, i)
 159                         __dma_sync(sg->dma_address, sg->length, direction);
 160 }
 161
 162 static
 163 int dma_direct_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
 164                              void *cpu_addr, dma_addr_t handle, size_t size,
 165                              unsigned long attrs)
 166 {
 167 #ifdef CONFIG_MMU
 168         unsigned long user_count = vma_pages(vma);
 169         unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 170         unsigned long off = vma->vm_pgoff;
 171         unsigned long pfn;
 172
 173         if (off >= count || user_count > (count - off))
 174                 return -ENXIO;
 175
 176 #ifdef NOT_COHERENT_CACHE
 177         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 178         pfn = consistent_virt_to_pfn(cpu_addr);
 179 #else
 180         pfn = virt_to_pfn(cpu_addr);
 181 #endif
 182         return remap_pfn_range(vma, vma->vm_start, pfn + off,
 183                                vma->vm_end - vma->vm_start, vma->vm_page_prot);
 184 #else
 185         return -ENXIO;
 186 #endif
 187 }
 188
 189 const struct dma_map_ops dma_direct_ops = {
 190         .alloc          = dma_direct_alloc_coherent,
 191         .free           = dma_direct_free_coherent,
 192         .mmap           = dma_direct_mmap_coherent,
 193         .map_sg         = dma_direct_map_sg,
 194         .dma_supported  = dma_direct_dma_supported,
 195         .map_page       = dma_direct_map_page,
 196         .unmap_page     = dma_direct_unmap_page,
 197         .sync_single_for_cpu            = dma_direct_sync_single_for_cpu,
 198         .sync_single_for_device         = dma_direct_sync_single_for_device,
 199         .sync_sg_for_cpu                = dma_direct_sync_sg_for_cpu,
 200         .sync_sg_for_device             = dma_direct_sync_sg_for_device,
 201 };
 202 EXPORT_SYMBOL(dma_direct_ops);
 203
 204 /* Number of entries preallocated for DMA-API debugging */
 205 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 206
 207 static int __init dma_init(void)
 208 {
 209         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 210
 211         return 0;
 212 }
 213 fs_initcall(dma_init);