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
  19 void *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 }
  47 EXPORT_SYMBOL(dma_alloc_coherent);
  48
  49 void 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 }
  56 EXPORT_SYMBOL(dma_free_coherent);