mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-22 20:23:57 +08:00
61 lines
1.8 KiB
C
61 lines
1.8 KiB
C
/*
|
|
* 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 */
|
|
#include <xtensa/config/core.h>
|
|
|
|
/*
|
|
* 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 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).
|
|
*/
|
|
#define MAX_DMA_ADDRESS (PAGE_OFFSET + XCHAL_KSEG_CACHED_SIZE - 1)
|
|
|
|
/* Reserve and release a DMA channel */
|
|
extern int request_dma(unsigned int dmanr, const char * device_id);
|
|
extern void free_dma(unsigned int dmanr);
|
|
|
|
#ifdef CONFIG_PCI
|
|
extern int isa_dma_bridge_buggy;
|
|
#else
|
|
#define isa_dma_bridge_buggy (0)
|
|
#endif
|
|
|
|
|
|
#endif
|