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dma.c

/*
 * Dynamic DMA mapping support.
 *
 * We never have any address translations to worry about, so this
 * is just alloc/free.
 */

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

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

      if (dev == NULL || (*dev->dma_mask < 0xffffffff))
            gfp |= GFP_DMA;
      ret = (void *)__get_free_pages(gfp, get_order(size));

      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)
{
      free_pages((unsigned long)vaddr, get_order(size));
}

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