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dma.c

/*
 * Dynamic DMA mapping support.
 *
 * On cris there is no hardware dynamic DMA address translation,
 * so consistent alloc/free are merely page allocation/freeing.
 * The rest of the dynamic DMA mapping interface is implemented
 * in asm/pci.h.
 *
 * Borrowed from i386.
 */

#include <linux/types.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <linux/gfp.h>
#include <asm/io.h>

void *dma_alloc_coherent(struct device *dev, size_t size,
                     dma_addr_t *dma_handle, gfp_t gfp)
{
      void *ret;
      int order = get_order(size);
      /* ignore region specifiers */
      gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);

      if (dma_alloc_from_coherent(dev, size, dma_handle, &ret))
            return ret;

      if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
            gfp |= GFP_DMA;

      ret = (void *)__get_free_pages(gfp, order);

      if (ret != NULL) {
            memset(ret, 0, size);
            *dma_handle = virt_to_phys(ret);
      }
      return ret;
}

void dma_free_coherent(struct device *dev, size_t size,
                   void *vaddr, dma_addr_t dma_handle)
{
      int order = get_order(size);

      if (!dma_release_from_coherent(dev, order, vaddr))
            free_pages((unsigned long)vaddr, order);
}


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