1/*
2 * include/asm-xtensa/dma.h
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License.  See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (C) 2003 - 2005 Tensilica Inc.
9 */
10
11#ifndef _XTENSA_DMA_H
12#define _XTENSA_DMA_H
13
14#include <asm/io.h>		/* need byte IO */
15
16/*
17 * This is only to be defined if we have PC-like DMA.
18 * By default this is not true on an Xtensa processor,
19 * however on boards with a PCI bus, such functionality
20 * might be emulated externally.
21 *
22 * NOTE:  there still exists driver code that assumes
23 * this is defined, eg. drivers/sound/soundcard.c (as of 2.4).
24 */
25#define MAX_DMA_CHANNELS	8
26
27/*
28 * The maximum virtual address to which DMA transfers
29 * can be performed on this platform.
30 *
31 * NOTE: This is board (platform) specific, not processor-specific!
32 *
33 * NOTE: This assumes DMA transfers can only be performed on
34 *	the section of physical memory contiguously mapped in virtual
35 *	space for the kernel.  For the Xtensa architecture, this
36 *	means the maximum possible size of this DMA area is
37 *	the size of the statically mapped kernel segment
38 *	(XCHAL_KSEG_{CACHED,BYPASS}_SIZE), ie. 128 MB.
39 *
40 * NOTE: When the entire KSEG area is DMA capable, we subtract
41 *	one from the max address so that the virt_to_phys() macro
42 *	works correctly on the address (otherwise the address
43 *	enters another area, and virt_to_phys() may not return
44 *	the value desired).
45 */
46
47#ifndef MAX_DMA_ADDRESS
48#define MAX_DMA_ADDRESS		(PAGE_OFFSET + XCHAL_KIO_SIZE - 1)
49#endif
50
51/* Reserve and release a DMA channel */
52extern int request_dma(unsigned int dmanr, const char * device_id);
53extern void free_dma(unsigned int dmanr);
54
55#endif
56