/* * 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).
*/ #define MAX_DMA_CHANNELS 8
/* * 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 * (XCHAL_KSEG_{CACHED,BYPASS}_SIZE), ie. 128 MB. * * NOTE: When the entire KSEG area is DMA capable, we subtract * 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).
*/
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