dma-alloc.c revision b920de1b77b72ca9432ac3f97edb26541e65e5dd 
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