blob: 137ca3945b07b55966b65a2ac2e89d0393fe4e8c [file] [log] [blame]
* include/asm-xtensa/dma.h
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
* Copyright (C) 2003 - 2005 Tensilica Inc.
#ifndef _XTENSA_DMA_H
#define _XTENSA_DMA_H
#include <asm/io.h> /* need byte IO */
* This is only to be defined if we have PC-like DMA.
* By default this is not true on an Xtensa processor,
* however on boards with a PCI bus, such functionality
* might be emulated externally.
* NOTE: there still exists driver code that assumes
* this is defined, eg. drivers/sound/soundcard.c (as of 2.4).
* The maximum virtual address to which DMA transfers
* can be performed on this platform.
* NOTE: This is board (platform) specific, not processor-specific!
* NOTE: This assumes DMA transfers can only be performed on
* the section of physical memory contiguously mapped in virtual
* space for the kernel. For the Xtensa architecture, this
* means the maximum possible size of this DMA area is
* the size of the statically mapped kernel segment
* NOTE: When the entire KSEG area is DMA capable, we substract
* one from the max address so that the virt_to_phys() macro
* works correctly on the address (otherwise the address
* enters another area, and virt_to_phys() may not return
* the value desired).
/* Reserve and release a DMA channel */
extern int request_dma(unsigned int dmanr, const char * device_id);
extern void free_dma(unsigned int dmanr);
extern int isa_dma_bridge_buggy;
#define isa_dma_bridge_buggy (0)