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Diffstat (limited to '')
| -rw-r--r-- | arch/xtensa/include/asm/dma.h | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/arch/xtensa/include/asm/dma.h b/arch/xtensa/include/asm/dma.h new file mode 100644 index 000000000..bb099a373 --- /dev/null +++ b/arch/xtensa/include/asm/dma.h @@ -0,0 +1,62 @@ +/* + * 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). + */ + +#ifndef MAX_DMA_ADDRESS +#define MAX_DMA_ADDRESS (PAGE_OFFSET + XCHAL_KIO_SIZE - 1) +#endif + +/* 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 |