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consistent.c

/*
 * Copyright (C) 2001 David J. Mckay (david.mckay@st.com)
 * Copyright (C) 2003 Paul Mundt (lethal@linux-sh.org)
 *
 * May be copied or modified under the terms of the GNU General Public
 * License.  See linux/COPYING for more information.
 *
 * Dynamic DMA mapping support.
 */
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <linux/dma-mapping.h>
#include <linux/module.h>
#include <asm/io.h>

void *consistent_alloc(struct pci_dev *hwdev, size_t size,
                     dma_addr_t *dma_handle)
{
      void *ret;
      int gfp = GFP_ATOMIC;
        void *vp;

      if (hwdev == NULL || hwdev->dma_mask != 0xffffffff)
            gfp |= GFP_DMA;

      ret = (void *)__get_free_pages(gfp, get_order(size));

      /* now call our friend ioremap_nocache to give us an uncached area */
        vp = ioremap_nocache(virt_to_phys(ret), size);

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

      return vp;
}
EXPORT_SYMBOL(consistent_alloc);

void consistent_free(struct pci_dev *hwdev, size_t size,
                   void *vaddr, dma_addr_t dma_handle)
{
      void *alloc;

      alloc = phys_to_virt((unsigned long)dma_handle);
      free_pages((unsigned long)alloc, get_order(size));

      iounmap(vaddr);
}
EXPORT_SYMBOL(consistent_free);

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