dma-alloc.c revision 5a0e3ad6af8660be21ca98a971cd00f331318c05 
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 <linux/gfp.h>
18#include <asm/io.h>
19
20static unsigned long pci_sram_allocated = 0xbc000000;
21
22void *dma_alloc_coherent(struct device *dev, size_t size,
23			 dma_addr_t *dma_handle, int gfp)
24{
25	unsigned long addr;
26	void *ret;
27
28	printk("dma_alloc_coherent(%s,%zu,,%x)\n", dev_name(dev), size, gfp);
29
30	if (0xbe000000 - pci_sram_allocated >= size) {
31		size = (size + 255) & ~255;
32		addr = pci_sram_allocated;
33		pci_sram_allocated += size;
34		ret = (void *) addr;
35		goto done;
36	}
37
38	/* ignore region specifiers */
39	gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
40
41	if (dev == NULL || dev->coherent_dma_mask < 0xffffffff)
42		gfp |= GFP_DMA;
43
44	addr = __get_free_pages(gfp, get_order(size));
45	if (!addr)
46		return NULL;
47
48	/* map the coherent memory through the uncached memory window */
49	ret = (void *) (addr | 0x20000000);
50
51	/* fill the memory with obvious rubbish */
52	memset((void *) addr, 0xfb, size);
53
54	/* write back and evict all cache lines covering this region */
55	mn10300_dcache_flush_inv_range2(virt_to_phys((void *) addr), PAGE_SIZE);
56
57done:
58	*dma_handle = virt_to_bus((void *) addr);
59	printk("dma_alloc_coherent() = %p [%x]\n", ret, *dma_handle);
60	return ret;
61}
62EXPORT_SYMBOL(dma_alloc_coherent);
63
64void dma_free_coherent(struct device *dev, size_t size, void *vaddr,
65		       dma_addr_t dma_handle)
66{
67	unsigned long addr = (unsigned long) vaddr & ~0x20000000;
68
69	if (addr >= 0x9c000000)
70		return;
71
72	free_pages(addr, get_order(size));
73}
74EXPORT_SYMBOL(dma_free_coherent);
75