arch/m68k/kernel/dma_no.c

   1 /*
   2  * Dynamic DMA mapping support.
   3  *
   4  * We never have any address translations to worry about, so this
   5  * is just alloc/free.
   6  */
   7
   8 #include <linux/types.h>
   9 #include <linux/gfp.h>
  10 #include <linux/mm.h>
  11 #include <linux/device.h>
  12 #include <linux/dma-mapping.h>
  13 #include <linux/export.h>
  14 #include <asm/cacheflush.h>
  15
  16 void *dma_alloc_coherent(struct device *dev, size_t size,
  17                            dma_addr_t *dma_handle, gfp_t gfp)
  18 {
  19         void *ret;
  20         /* ignore region specifiers */
  21         gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  22
  23         if (dev == NULL || (*dev->dma_mask < 0xffffffff))
  24                 gfp |= GFP_DMA;
  25         ret = (void *)__get_free_pages(gfp, get_order(size));
  26
  27         if (ret != NULL) {
  28                 memset(ret, 0, size);
  29                 *dma_handle = virt_to_phys(ret);
  30         }
  31         return ret;
  32 }
  33
  34 void dma_free_coherent(struct device *dev, size_t size,
  35                          void *vaddr, dma_addr_t dma_handle)
  36 {
  37         free_pages((unsigned long)vaddr, get_order(size));
  38 }
  39
  40 void dma_sync_single_for_device(struct device *dev, dma_addr_t handle,
  41                                 size_t size, enum dma_data_direction dir)
  42 {
  43         switch (dir) {
  44         case DMA_TO_DEVICE:
  45                 flush_dcache_range(handle, size);
  46                 break;
  47         case DMA_FROM_DEVICE:
  48                 /* Should be clear already */
  49                 break;
  50         default:
  51                 if (printk_ratelimit())
  52                         printk("dma_sync_single_for_device: unsupported dir %u\n", dir);
  53                 break;
  54         }
  55 }
  56
  57 EXPORT_SYMBOL(dma_sync_single_for_device);
  58 dma_addr_t dma_map_single(struct device *dev, void *addr, size_t size,
  59                           enum dma_data_direction dir)
  60 {
  61         dma_addr_t handle = virt_to_phys(addr);
  62         flush_dcache_range(handle, size);
  63         return handle;
  64 }
  65 EXPORT_SYMBOL(dma_map_single);
  66
  67 dma_addr_t dma_map_page(struct device *dev, struct page *page,
  68                         unsigned long offset, size_t size,
  69                         enum dma_data_direction dir)
  70 {
  71         dma_addr_t handle = page_to_phys(page) + offset;
  72         dma_sync_single_for_device(dev, handle, size, dir);
  73         return handle;
  74 }
  75 EXPORT_SYMBOL(dma_map_page);