/* $Id: dma.h,v 1.7 1992/12/14 00:29:34 root Exp root $ * linux/include/asm/dma.h: Defines for using and allocating dma channels. * Written by Hennus Bergman, 1992. * High DMA channel support & info by Hannu Savolainen * and John Boyd, Nov. 1992. */#ifndef _ASM_DMA_H#define _ASM_DMA_H#include <asm/io.h>		/* need byte IO */#ifdef HAVE_REALLY_SLOW_DMA_CONTROLLER#define outb	outb_p#endif/* * NOTES about DMA transfers: * *  controller 1: channels 0-3, byte operations, ports 00-1F *  controller 2: channels 4-7, word operations, ports C0-DF * *  - ALL registers are 8 bits only, regardless of transfer size *  - channel 4 is not used - cascades 1 into 2. *  - channels 0-3 are byte - addresses/counts are for physical bytes *  - channels 5-7 are word - addresses/counts are for physical words *  - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries *  - transfer count loaded to registers is 1 less than actual count *  - controller 2 offsets are all even (2x offsets for controller 1) *  - page registers for 5-7 don't use data bit 0, represent 128K pages *  - page registers for 0-3 use bit 0, represent 64K pages * * DMA transfers are limited to the lower 16MB of _physical_ memory.   * Note that addresses loaded into registers must be _physical_ addresses, * not logical addresses (which may differ if paging is active). * *  Address mapping for channels 0-3: * *   A23 ... A16 A15 ... A8  A7 ... A0    (Physical addresses) *    |  ...  |   |  ... |   |  ... | *    |  ...  |   |  ... |   |  ... | *    |  ...  |   |  ... |   |  ... | *   P7  ...  P0  A7 ... A0  A7 ... A0    * |    Page    | Addr MSB | Addr LSB |   (DMA registers) * *  Address mapping for channels 5-7: * *   A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0    (Physical addresses) *    |  ...  |   \   \   ... \  \  \  ... \  \ *    |  ...  |    \   \   ... \  \  \  ... \  (not used) *    |  ...  |     \   \   ... \  \  \  ... \ *   P7  ...  P1 (0) A7 A6  ... A0 A7 A6 ... A0    * |      Page      |  Addr MSB   |  Addr LSB  |   (DMA registers) * * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at * the hardware level, so odd-byte transfers aren't possible). * * Transfer count (_not # bytes_) is limited to 64K, represented as actual * count - 1 : 64K => 0xFFFF, 1 => 0x0000.  Thus, count is always 1 or more, * and up to 128K bytes may be transferred on channels 5-7 in one operation.  * */#define MAX_DMA_CHANNELS	8/* 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 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 DMA_ADDR_0              0x00    /* DMA address registers */#define DMA_ADDR_1              0x02#define DMA_ADDR_2              0x04#define DMA_ADDR_3              0x06#define DMA_ADDR_4              0xC0#define DMA_ADDR_5              0xC4#define DMA_ADDR_6              0xC8#define DMA_ADDR_7              0xCC#define DMA_CNT_0               0x01    /* DMA count registers */#define DMA_CNT_1               0x03#define DMA_CNT_2               0x05#define DMA_CNT_3               0x07#define DMA_CNT_4               0xC2#define DMA_CNT_5               0xC6#define DMA_CNT_6               0xCA#define DMA_CNT_7               0xCE#define DMA_PAGE_0              0x87    /* DMA page registers */#define DMA_PAGE_1              0x83#define DMA_PAGE_2              0x81#define DMA_PAGE_3              0x82#define DMA_PAGE_5              0x8B#define DMA_PAGE_6              0x89#define DMA_PAGE_7              0x8A#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 *//* enable/disable a specific DMA channel */static __inline__ void enable_dma(unsigned int dmanr){	if (dmanr<=3)		outb(dmanr,  DMA1_MASK_REG);	else		outb(dmanr & 3,  DMA2_MASK_REG);}static __inline__ void disable_dma(unsigned int dmanr){	if (dmanr<=3)		outb(dmanr | 4,  DMA1_MASK_REG);	else		outb((dmanr & 3) | 4,  DMA2_MASK_REG);}/* Clear the 'DMA Pointer Flip Flop'. * Write 0 for LSB/MSB, 1 for MSB/LSB access. * Use this once to initialize the FF to a known state. * After that, keep track of it. :-) * --- In order to do that, the DMA routines below should --- * --- only be used while interrupts are disabled! --- */static __inline__ void clear_dma_ff(unsigned int dmanr){	if (dmanr<=3)		outb(0,  DMA1_CLEAR_FF_REG);	else		outb(0,  DMA2_CLEAR_FF_REG);}/* set mode (above) for a specific DMA channel */static __inline__ void set_dma_mode(unsigned int dmanr, char mode){	if (dmanr<=3)		outb(mode | dmanr,  DMA1_MODE_REG);	else		outb(mode | (dmanr&3),  DMA2_MODE_REG);}/* Set only the page register bits of the transfer address. * This is used for successive transfers when we know the contents of * the lower 16 bits of the DMA current address register, but a 64k boundary * may have been crossed. */static __inline__ void set_dma_page(unsigned int dmanr, char pagenr){	switch(dmanr) {		case 0:			outb(pagenr, DMA_PAGE_0);			break;		case 1:			outb(pagenr, DMA_PAGE_1);			break;		case 2:			outb(pagenr, DMA_PAGE_2);			break;		case 3:			outb(pagenr, DMA_PAGE_3);			break;		case 5:			outb(pagenr & 0xfe, DMA_PAGE_5);			break;		case 6:			outb(pagenr & 0xfe, DMA_PAGE_6);			break;		case 7:			outb(pagenr & 0xfe, DMA_PAGE_7);			break;	}}/* Set transfer address & page bits for specific DMA channel. * Assumes dma flipflop is clear. */static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a){	set_dma_page(dmanr, a>>16);	if (dmanr <= 3)  {	    outb( a & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );            outb( (a>>8) & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );	}  else  {	    outb( (a>>1) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );	    outb( (a>>9) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );	}}/* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for * a specific DMA channel. * You must ensure the parameters are valid. * NOTE: from a manual: "the number of transfers is one more * than the initial word count"! This is taken into account. * Assumes dma flip-flop is clear. * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7. */static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count){        count--;	if (dmanr <= 3)  {	    outb( count & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );	    outb( (count>>8) & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );        } else {	    outb( (count>>1) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );	    outb( (count>>9) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );        }}/* 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;	/* using short to get 16-bit wrap around */	unsigned short count;	count = 1 + inb(io_port);	count += inb(io_port) << 8;		return (dmanr<=3)? count : (count<<1);}/* These are in kernel/dma.c: */extern int request_dma(unsigned int dmanr);	/* reserve a DMA channel */extern void free_dma(unsigned int dmanr);	/* release it again */#endif /* _ASM_DMA_H */