arch/cris/arch-v32/drivers/pci/dma.c

   1 /*
   2  * Dynamic DMA mapping support.
   3  *
   4  * On cris there is no hardware dynamic DMA address translation,
   5  * so consistent alloc/free are merely page allocation/freeing.
   6  * The rest of the dynamic DMA mapping interface is implemented
   7  * in asm/pci.h.
   8  *
   9  * Borrowed from i386.
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/mm.h>
  14 #include <linux/string.h>
  15 #include <linux/pci.h>
  16 #include <linux/gfp.h>
  17 #include <asm/io.h>
  18
  19 static void *v32_dma_alloc(struct device *dev, size_t size,
  20                 dma_addr_t *dma_handle, gfp_t gfp,  struct dma_attrs *attrs)
  21 {
  22         void *ret;
  23
  24         /* ignore region specifiers */
  25         gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  26
  27         if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
  28                 gfp |= GFP_DMA;
  29
  30         ret = (void *)__get_free_pages(gfp,  get_order(size));
  31
  32         if (ret != NULL) {
  33                 memset(ret, 0, size);
  34                 *dma_handle = virt_to_phys(ret);
  35         }
  36         return ret;
  37 }
  38
  39 static void v32_dma_free(struct device *dev, size_t size, void *vaddr,
  40                 dma_addr_t dma_handle, struct dma_attrs *attrs)
  41 {
  42         free_pages((unsigned long)vaddr, get_order(size));
  43 }
  44
  45 static inline dma_addr_t v32_dma_map_page(struct device *dev,
  46                 struct page *page, unsigned long offset, size_t size,
  47                 enum dma_data_direction direction,
  48                 struct dma_attrs *attrs)
  49 {
  50         return page_to_phys(page) + offset;
  51 }
  52
  53 static inline int v32_dma_map_sg(struct device *dev, struct scatterlist *sg,
  54                 int nents, enum dma_data_direction direction,
  55                 struct dma_attrs *attrs)
  56 {
  57         printk("Map sg\n");
  58         return nents;
  59 }
  60
  61 static inline int v32_dma_supported(struct device *dev, u64 mask)
  62 {
  63         /*
  64          * we fall back to GFP_DMA when the mask isn't all 1s,
  65          * so we can't guarantee allocations that must be
  66          * within a tighter range than GFP_DMA..
  67          */
  68         if (mask < 0x00ffffff)
  69                 return 0;
  70         return 1;
  71 }
  72
  73 struct dma_map_ops v32_dma_ops = {
  74         .alloc                  = v32_dma_alloc,
  75         .free                   = v32_dma_free,
  76         .map_page               = v32_dma_map_page,
  77         .map_sg                 = v32_dma_map_sg,
  78         .dma_supported          = v32_dma_supported,
  79 };
  80 EXPORT_SYMBOL(v32_dma_ops);