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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* $Id: dma.h,v 1.2 1999/04/27 00:46:18 deller Exp $
2 * linux/include/asm/dma.h: Defines for using and allocating dma channels.
3 * Written by Hennus Bergman, 1992.
4 * High DMA channel support & info by Hannu Savolainen
5 * and John Boyd, Nov. 1992.
6 * (c) Copyright 2000, Grant Grundler
7 */
8
9#ifndef _ASM_DMA_H
10#define _ASM_DMA_H
11
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <asm/io.h> /* need byte IO */
13#include <asm/system.h>
14
15#define dma_outb outb
16#define dma_inb inb
17
18/*
19** DMA_CHUNK_SIZE is used by the SCSI mid-layer to break up
20** (or rather not merge) DMA's into managable chunks.
21** On parisc, this is more of the software/tuning constraint
22** rather than the HW. I/O MMU allocation alogorithms can be
23** faster with smaller size is (to some degree).
24*/
25#define DMA_CHUNK_SIZE (BITS_PER_LONG*PAGE_SIZE)
26
27/* The maximum address that we can perform a DMA transfer to on this platform
28** New dynamic DMA interfaces should obsolete this....
29*/
30#define MAX_DMA_ADDRESS (~0UL)
31
32/*
33** We don't have DMA channels... well V-class does but the
34** Dynamic DMA Mapping interface will support them... right? :^)
35** Note: this is not relevant right now for PA-RISC, but we cannot
36** leave this as undefined because some things (e.g. sound)
37** won't compile :-(
38*/
39#define MAX_DMA_CHANNELS 8
40#define DMA_MODE_READ 0x44 /* I/O to memory, no autoinit, increment, single mode */
41#define DMA_MODE_WRITE 0x48 /* memory to I/O, no autoinit, increment, single mode */
42#define DMA_MODE_CASCADE 0xC0 /* pass thru DREQ->HRQ, DACK<-HLDA only */
43
44#define DMA_AUTOINIT 0x10
45
46/* 8237 DMA controllers */
47#define IO_DMA1_BASE 0x00 /* 8 bit slave DMA, channels 0..3 */
48#define IO_DMA2_BASE 0xC0 /* 16 bit master DMA, ch 4(=slave input)..7 */
49
50/* DMA controller registers */
51#define DMA1_CMD_REG 0x08 /* command register (w) */
52#define DMA1_STAT_REG 0x08 /* status register (r) */
53#define DMA1_REQ_REG 0x09 /* request register (w) */
54#define DMA1_MASK_REG 0x0A /* single-channel mask (w) */
55#define DMA1_MODE_REG 0x0B /* mode register (w) */
56#define DMA1_CLEAR_FF_REG 0x0C /* clear pointer flip-flop (w) */
57#define DMA1_TEMP_REG 0x0D /* Temporary Register (r) */
58#define DMA1_RESET_REG 0x0D /* Master Clear (w) */
59#define DMA1_CLR_MASK_REG 0x0E /* Clear Mask */
60#define DMA1_MASK_ALL_REG 0x0F /* all-channels mask (w) */
61#define DMA1_EXT_MODE_REG (0x400 | DMA1_MODE_REG)
62
63#define DMA2_CMD_REG 0xD0 /* command register (w) */
64#define DMA2_STAT_REG 0xD0 /* status register (r) */
65#define DMA2_REQ_REG 0xD2 /* request register (w) */
66#define DMA2_MASK_REG 0xD4 /* single-channel mask (w) */
67#define DMA2_MODE_REG 0xD6 /* mode register (w) */
68#define DMA2_CLEAR_FF_REG 0xD8 /* clear pointer flip-flop (w) */
69#define DMA2_TEMP_REG 0xDA /* Temporary Register (r) */
70#define DMA2_RESET_REG 0xDA /* Master Clear (w) */
71#define DMA2_CLR_MASK_REG 0xDC /* Clear Mask */
72#define DMA2_MASK_ALL_REG 0xDE /* all-channels mask (w) */
73#define DMA2_EXT_MODE_REG (0x400 | DMA2_MODE_REG)
74
Linus Torvalds1da177e2005-04-16 15:20:36 -070075static __inline__ unsigned long claim_dma_lock(void)
76{
Matthew Wilcox99b6e9b2006-09-20 20:36:42 -060077 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070078}
79
80static __inline__ void release_dma_lock(unsigned long flags)
81{
Linus Torvalds1da177e2005-04-16 15:20:36 -070082}
83
84
85/* Get DMA residue count. After a DMA transfer, this
86 * should return zero. Reading this while a DMA transfer is
87 * still in progress will return unpredictable results.
88 * If called before the channel has been used, it may return 1.
89 * Otherwise, it returns the number of _bytes_ left to transfer.
90 *
91 * Assumes DMA flip-flop is clear.
92 */
93static __inline__ int get_dma_residue(unsigned int dmanr)
94{
95 unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE
96 : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE;
97
98 /* using short to get 16-bit wrap around */
99 unsigned short count;
100
101 count = 1 + dma_inb(io_port);
102 count += dma_inb(io_port) << 8;
103
104 return (dmanr<=3)? count : (count<<1);
105}
106
107/* enable/disable a specific DMA channel */
108static __inline__ void enable_dma(unsigned int dmanr)
109{
110#ifdef CONFIG_SUPERIO
111 if (dmanr<=3)
112 dma_outb(dmanr, DMA1_MASK_REG);
113 else
114 dma_outb(dmanr & 3, DMA2_MASK_REG);
115#endif
116}
117
118static __inline__ void disable_dma(unsigned int dmanr)
119{
120#ifdef CONFIG_SUPERIO
121 if (dmanr<=3)
122 dma_outb(dmanr | 4, DMA1_MASK_REG);
123 else
124 dma_outb((dmanr & 3) | 4, DMA2_MASK_REG);
125#endif
126}
127
128/* reserve a DMA channel */
129#define request_dma(dmanr, device_id) (0)
130
131/* Clear the 'DMA Pointer Flip Flop'.
132 * Write 0 for LSB/MSB, 1 for MSB/LSB access.
133 * Use this once to initialize the FF to a known state.
134 * After that, keep track of it. :-)
135 * --- In order to do that, the DMA routines below should ---
136 * --- only be used while holding the DMA lock ! ---
137 */
138static __inline__ void clear_dma_ff(unsigned int dmanr)
139{
140}
141
142/* set mode (above) for a specific DMA channel */
143static __inline__ void set_dma_mode(unsigned int dmanr, char mode)
144{
145}
146
147/* Set only the page register bits of the transfer address.
148 * This is used for successive transfers when we know the contents of
149 * the lower 16 bits of the DMA current address register, but a 64k boundary
150 * may have been crossed.
151 */
152static __inline__ void set_dma_page(unsigned int dmanr, char pagenr)
153{
154}
155
156
157/* Set transfer address & page bits for specific DMA channel.
158 * Assumes dma flipflop is clear.
159 */
160static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a)
161{
162}
163
164
165/* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for
166 * a specific DMA channel.
167 * You must ensure the parameters are valid.
168 * NOTE: from a manual: "the number of transfers is one more
169 * than the initial word count"! This is taken into account.
170 * Assumes dma flip-flop is clear.
171 * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7.
172 */
173static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count)
174{
175}
176
177
178#define free_dma(dmanr)
179
180#ifdef CONFIG_PCI
181extern int isa_dma_bridge_buggy;
182#else
183#define isa_dma_bridge_buggy (0)
184#endif
185
186#endif /* _ASM_DMA_H */