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dma-alloc.c

/* MN10300 Dynamic DMA mapping support
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 * Derived from: arch/i386/kernel/pci-dma.c
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

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

void *dma_alloc_coherent(struct device *dev, size_t size,
                   dma_addr_t *dma_handle, int gfp)
{
      unsigned long addr;
      void *ret;

      /* ignore region specifiers */
      gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);

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

      addr = __get_free_pages(gfp, get_order(size));
      if (!addr)
            return NULL;

      /* map the coherent memory through the uncached memory window */
      ret = (void *) (addr | 0x20000000);

      /* fill the memory with obvious rubbish */
      memset((void *) addr, 0xfb, size);

      /* write back and evict all cache lines covering this region */
      mn10300_dcache_flush_inv_range2(virt_to_phys((void *) addr), PAGE_SIZE);

      *dma_handle = virt_to_bus((void *) addr);
      return ret;
}
EXPORT_SYMBOL(dma_alloc_coherent);

void dma_free_coherent(struct device *dev, size_t size, void *vaddr,
                   dma_addr_t dma_handle)
{
      unsigned long addr = (unsigned long) vaddr & ~0x20000000;

      free_pages(addr, get_order(size));
}
EXPORT_SYMBOL(dma_free_coherent);

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