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 <asm/cacheflush.h>
  14
  15 void *dma_alloc_coherent(struct device *dev, size_t size,
  16                            dma_addr_t *dma_handle, gfp_t gfp)
  17 {
  18         void *ret;
  19         /* ignore region specifiers */
  20         gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  21
  22         if (dev == NULL || (*dev->dma_mask < 0xffffffff))
  23                 gfp |= GFP_DMA;
  24         ret = (void *)__get_free_pages(gfp, get_order(size));
  25
  26         if (ret != NULL) {
  27                 memset(ret, 0, size);
  28                 *dma_handle = virt_to_phys(ret);
  29         }
  30         return ret;
  31 }
  32
  33 void dma_free_coherent(struct device *dev, size_t size,
  34                          void *vaddr, dma_addr_t dma_handle)
  35 {
  36         free_pages((unsigned long)vaddr, get_order(size));
  37 }
  38
  39 void dma_sync_single_for_device(struct device *dev, dma_addr_t handle,
  40                                 size_t size, enum dma_data_direction dir)
  41 {
  42         switch (dir) {
  43         case DMA_TO_DEVICE:
  44                 flush_dcache_range(handle, size);
  45                 break;
  46         case DMA_FROM_DEVICE:
  47                 /* Should be clear already */
  48                 break;
  49         default:
  50                 if (printk_ratelimit())
  51                         printk("dma_sync_single_for_device: unsupported dir %u\n", dir);
  52                 break;
  53         }
  54 }
  55
  56 EXPORT_SYMBOL(dma_sync_single_for_device);
  57 dma_addr_t dma_map_single(struct device *dev, void *addr, size_t size,
  58                           enum dma_data_direction dir)
  59 {
  60         dma_addr_t handle = virt_to_phys(addr);
  61         flush_dcache_range(handle, size);
  62         return handle;
  63 }
  64 EXPORT_SYMBOL(dma_map_single);
  65
  66 dma_addr_t dma_map_page(struct device *dev, struct page *page,
  67                         unsigned long offset, size_t size,
  68                         enum dma_data_direction dir)
  69 {
  70         dma_addr_t handle = page_to_phys(page) + offset;
  71         dma_sync_single_for_device(dev, handle, size, dir);
  72         return handle;
  73 }
  74 EXPORT_SYMBOL(dma_map_page);