arch/parisc/include/asm/dma.h

Source file repositories/reference/linux-study-clean/arch/parisc/include/asm/dma.h

File Facts

System
Linux kernel
Corpus path
arch/parisc/include/asm/dma.h
Extension
.h
Size
5788 bytes
Lines
182
Domain
Architecture Layer
Bucket
arch/parisc
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef _ASM_DMA_H
#define _ASM_DMA_H

#include <asm/io.h>		/* need byte IO */

#define dma_outb	outb
#define dma_inb		inb

extern unsigned long pcxl_dma_start;

/*
** DMA_CHUNK_SIZE is used by the SCSI mid-layer to break up
** (or rather not merge) DMAs into manageable chunks.
** On parisc, this is more of the software/tuning constraint
** rather than the HW. I/O MMU allocation algorithms can be
** faster with smaller sizes (to some degree).
*/
#define DMA_CHUNK_SIZE	(BITS_PER_LONG*PAGE_SIZE)

/* The maximum address that we can perform a DMA transfer to on this platform
** New dynamic DMA interfaces should obsolete this....
*/
#define MAX_DMA_ADDRESS (~0UL)

/*
** We don't have DMA channels... well V-class does but the
** Dynamic DMA Mapping interface will support them... right? :^)
** Note: this is not relevant right now for PA-RISC, but we cannot 
** leave this as undefined because some things (e.g. sound)
** won't compile :-(
*/
#define MAX_DMA_CHANNELS 8
#define DMA_MODE_READ	0x44	/* I/O to memory, no autoinit, increment, single mode */
#define DMA_MODE_WRITE	0x48	/* memory to I/O, no autoinit, increment, single mode */
#define DMA_MODE_CASCADE 0xC0	/* pass thru DREQ->HRQ, DACK<-HLDA only */

#define DMA_AUTOINIT	0x10

/* 8237 DMA controllers */
#define IO_DMA1_BASE	0x00	/* 8 bit slave DMA, channels 0..3 */
#define IO_DMA2_BASE	0xC0	/* 16 bit master DMA, ch 4(=slave input)..7 */

/* DMA controller registers */
#define DMA1_CMD_REG		0x08	/* command register (w) */
#define DMA1_STAT_REG		0x08	/* status register (r) */
#define DMA1_REQ_REG            0x09    /* request register (w) */
#define DMA1_MASK_REG		0x0A	/* single-channel mask (w) */
#define DMA1_MODE_REG		0x0B	/* mode register (w) */
#define DMA1_CLEAR_FF_REG	0x0C	/* clear pointer flip-flop (w) */
#define DMA1_TEMP_REG           0x0D    /* Temporary Register (r) */
#define DMA1_RESET_REG		0x0D	/* Master Clear (w) */
#define DMA1_CLR_MASK_REG       0x0E    /* Clear Mask */
#define DMA1_MASK_ALL_REG       0x0F    /* all-channels mask (w) */
#define DMA1_EXT_MODE_REG	(0x400 | DMA1_MODE_REG)

#define DMA2_CMD_REG		0xD0	/* command register (w) */
#define DMA2_STAT_REG		0xD0	/* status register (r) */
#define DMA2_REQ_REG            0xD2    /* request register (w) */
#define DMA2_MASK_REG		0xD4	/* single-channel mask (w) */
#define DMA2_MODE_REG		0xD6	/* mode register (w) */
#define DMA2_CLEAR_FF_REG	0xD8	/* clear pointer flip-flop (w) */
#define DMA2_TEMP_REG           0xDA    /* Temporary Register (r) */
#define DMA2_RESET_REG		0xDA	/* Master Clear (w) */
#define DMA2_CLR_MASK_REG       0xDC    /* Clear Mask */
#define DMA2_MASK_ALL_REG       0xDE    /* all-channels mask (w) */
#define DMA2_EXT_MODE_REG	(0x400 | DMA2_MODE_REG)

static __inline__ unsigned long claim_dma_lock(void)
{
	return 0;
}

static __inline__ void release_dma_lock(unsigned long flags)
{
}


/* Get DMA residue count. After a DMA transfer, this
 * should return zero. Reading this while a DMA transfer is
 * still in progress will return unpredictable results.
 * If called before the channel has been used, it may return 1.
 * Otherwise, it returns the number of _bytes_ left to transfer.
 *
 * Assumes DMA flip-flop is clear.
 */
static __inline__ int get_dma_residue(unsigned int dmanr)
{
	unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE
					 : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE;

Annotation

Implementation Notes