LXR linux/arch/mn10300/mm/dma-alloc.c

   1/* MN10300 Dynamic DMA mapping support
   2 *
   3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4 * Written by David Howells (dhowells@redhat.com)
   5 * Derived from: arch/i386/kernel/pci-dma.c
   6 *
   7 * This program is free software; you can redistribute it and/or
   8 * modify it under the terms of the GNU General Public Licence
   9 * as published by the Free Software Foundation; either version
  10 * 2 of the Licence, or (at your option) any later version.
  11 */
  12
  13#include <linux/types.h>
  14#include <linux/mm.h>
  15#include <linux/string.h>
  16#include <linux/pci.h>
  17#include <asm/io.h>
  18
  19void *dma_alloc_coherent(struct device *dev, size_t size,
  20                         dma_addr_t *dma_handle, int gfp)
  21{
  22        unsigned long addr;
  23        void *ret;
  24
  25        /* ignore region specifiers */
  26        gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  27
  28        if (dev == NULL || dev->coherent_dma_mask < 0xffffffff)
  29                gfp |= GFP_DMA;
  30
  31        addr = __get_free_pages(gfp, get_order(size));
  32        if (!addr)
  33                return NULL;
  34
  35        /* map the coherent memory through the uncached memory window */
  36        ret = (void *) (addr | 0x20000000);
  37
  38        /* fill the memory with obvious rubbish */
  39        memset((void *) addr, 0xfb, size);
  40
  41        /* write back and evict all cache lines covering this region */
  42        mn10300_dcache_flush_inv_range2(virt_to_phys((void *) addr), PAGE_SIZE);
  43
  44        *dma_handle = virt_to_bus((void *) addr);
  45        return ret;
  46}
  47EXPORT_SYMBOL(dma_alloc_coherent);
  48
  49void dma_free_coherent(struct device *dev, size_t size, void *vaddr,
  50                       dma_addr_t dma_handle)
  51{
  52        unsigned long addr = (unsigned long) vaddr & ~0x20000000;
  53
  54        free_pages(addr, get_order(size));
  55}
  56EXPORT_SYMBOL(dma_free_coherent);
  57