source: GPL/trunk/include/asm/dma.h@ 260

Last change on this file since 260 was 32, checked in by vladest, 20 years ago

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1/* $Id: dma.h,v 1.1.1.1 2003/07/02 13:56:58 eleph 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 */
7
8#ifndef _ASM_DMA_H
9#define _ASM_DMA_H
10
11#include <asm/io.h> /* need byte IO */
12#include <linux/delay.h>
13#include <linux/spinlock.h> /* And spinlocks */
14
15
16#ifdef HAVE_REALLY_SLOW_DMA_CONTROLLER
17#define dma_outb outb_p
18#else
19#define dma_outb outb
20#endif
21
22#define dma_inb inb
23
24/*
25 * NOTES about DMA transfers:
26 *
27 * controller 1: channels 0-3, byte operations, ports 00-1F
28 * controller 2: channels 4-7, word operations, ports C0-DF
29 *
30 * - ALL registers are 8 bits only, regardless of transfer size
31 * - channel 4 is not used - cascades 1 into 2.
32 * - channels 0-3 are byte - addresses/counts are for physical bytes
33 * - channels 5-7 are word - addresses/counts are for physical words
34 * - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries
35 * - transfer count loaded to registers is 1 less than actual count
36 * - controller 2 offsets are all even (2x offsets for controller 1)
37 * - page registers for 5-7 don't use data bit 0, represent 128K pages
38 * - page registers for 0-3 use bit 0, represent 64K pages
39 *
40 * DMA transfers are limited to the lower 16MB of _physical_ memory.
41 * Note that addresses loaded into registers must be _physical_ addresses,
42 * not logical addresses (which may differ if paging is active).
43 *
44 * Address mapping for channels 0-3:
45 *
46 * A23 ... A16 A15 ... A8 A7 ... A0 (Physical addresses)
47 * | ... | | ... | | ... |
48 * | ... | | ... | | ... |
49 * | ... | | ... | | ... |
50 * P7 ... P0 A7 ... A0 A7 ... A0
51 * | Page | Addr MSB | Addr LSB | (DMA registers)
52 *
53 * Address mapping for channels 5-7:
54 *
55 * A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0 (Physical addresses)
56 * | ... | \ \ ... \ \ \ ... \ \
57 * | ... | \ \ ... \ \ \ ... \ (not used)
58 * | ... | \ \ ... \ \ \ ... \
59 * P7 ... P1 (0) A7 A6 ... A0 A7 A6 ... A0
60 * | Page | Addr MSB | Addr LSB | (DMA registers)
61 *
62 * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses
63 * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at
64 * the hardware level, so odd-byte transfers aren't possible).
65 *
66 * Transfer count (_not # bytes_) is limited to 64K, represented as actual
67 * count - 1 : 64K => 0xFFFF, 1 => 0x0000. Thus, count is always 1 or more,
68 * and up to 128K bytes may be transferred on channels 5-7 in one operation.
69 *
70 */
71
72#define MAX_DMA_CHANNELS 8
73
74/* The maximum address that we can perform a DMA transfer to on this platform */
75#define MAX_DMA_ADDRESS (PAGE_OFFSET+0x1000000)
76
77/* 8237 DMA controllers */
78#define IO_DMA1_BASE 0x00 /* 8 bit slave DMA, channels 0..3 */
79#define IO_DMA2_BASE 0xC0 /* 16 bit master DMA, ch 4(=slave input)..7 */
80
81/* DMA controller registers */
82#define DMA1_CMD_REG 0x08 /* command register (w) */
83#define DMA1_STAT_REG 0x08 /* status register (r) */
84#define DMA1_REQ_REG 0x09 /* request register (w) */
85#define DMA1_MASK_REG 0x0A /* single-channel mask (w) */
86#define DMA1_MODE_REG 0x0B /* mode register (w) */
87#define DMA1_CLEAR_FF_REG 0x0C /* clear pointer flip-flop (w) */
88#define DMA1_TEMP_REG 0x0D /* Temporary Register (r) */
89#define DMA1_RESET_REG 0x0D /* Master Clear (w) */
90#define DMA1_CLR_MASK_REG 0x0E /* Clear Mask */
91#define DMA1_MASK_ALL_REG 0x0F /* all-channels mask (w) */
92
93#define DMA2_CMD_REG 0xD0 /* command register (w) */
94#define DMA2_STAT_REG 0xD0 /* status register (r) */
95#define DMA2_REQ_REG 0xD2 /* request register (w) */
96#define DMA2_MASK_REG 0xD4 /* single-channel mask (w) */
97#define DMA2_MODE_REG 0xD6 /* mode register (w) */
98#define DMA2_CLEAR_FF_REG 0xD8 /* clear pointer flip-flop (w) */
99#define DMA2_TEMP_REG 0xDA /* Temporary Register (r) */
100#define DMA2_RESET_REG 0xDA /* Master Clear (w) */
101#define DMA2_CLR_MASK_REG 0xDC /* Clear Mask */
102#define DMA2_MASK_ALL_REG 0xDE /* all-channels mask (w) */
103
104#define DMA_ADDR_0 0x00 /* DMA address registers */
105#define DMA_ADDR_1 0x02
106#define DMA_ADDR_2 0x04
107#define DMA_ADDR_3 0x06
108#define DMA_ADDR_4 0xC0
109#define DMA_ADDR_5 0xC4
110#define DMA_ADDR_6 0xC8
111#define DMA_ADDR_7 0xCC
112
113#define DMA_CNT_0 0x01 /* DMA count registers */
114#define DMA_CNT_1 0x03
115#define DMA_CNT_2 0x05
116#define DMA_CNT_3 0x07
117#define DMA_CNT_4 0xC2
118#define DMA_CNT_5 0xC6
119#define DMA_CNT_6 0xCA
120#define DMA_CNT_7 0xCE
121
122#define DMA_PAGE_0 0x87 /* DMA page registers */
123#define DMA_PAGE_1 0x83
124#define DMA_PAGE_2 0x81
125#define DMA_PAGE_3 0x82
126#define DMA_PAGE_5 0x8B
127#define DMA_PAGE_6 0x89
128#define DMA_PAGE_7 0x8A
129
130#define DMA_MODE_READ 0x44 /* I/O to memory, no autoinit, increment, single mode */
131#define DMA_MODE_WRITE 0x48 /* memory to I/O, no autoinit, increment, single mode */
132#define DMA_MODE_CASCADE 0xC0 /* pass thru DREQ->HRQ, DACK<-HLDA only */
133
134#define DMA_AUTOINIT 0x10
135
136extern spinlock_t dma_spin_lock;
137
138unsigned long claim_dma_lock(void);
139void release_dma_lock(unsigned long flags);
140/* enable/disable a specific DMA channel */
141void enable_dma(unsigned int dmanr);
142
143void disable_dma(unsigned int dmanr);
144
145/* Clear the 'DMA Pointer Flip Flop'.
146 * Write 0 for LSB/MSB, 1 for MSB/LSB access.
147 * Use this once to initialize the FF to a known state.
148 * After that, keep track of it. :-)
149 * --- In order to do that, the DMA routines below should ---
150 * --- only be used while holding the DMA lock ! ---
151 */
152static __inline__ void clear_dma_ff(unsigned int dmanr)
153{
154 if (dmanr<=3)
155 dma_outb(0, DMA1_CLEAR_FF_REG);
156 else
157 dma_outb(0, DMA2_CLEAR_FF_REG);
158}
159
160/* set mode (above) for a specific DMA channel */
161static __inline__ void set_dma_mode(unsigned int dmanr, char mode)
162{
163 if (dmanr<=3)
164 dma_outb(mode | dmanr, DMA1_MODE_REG);
165 else
166 dma_outb(mode | (dmanr&3), DMA2_MODE_REG);
167}
168
169/* Set only the page register bits of the transfer address.
170 * This is used for successive transfers when we know the contents of
171 * the lower 16 bits of the DMA current address register, but a 64k boundary
172 * may have been crossed.
173 */
174static __inline__ void set_dma_page(unsigned int dmanr, char pagenr)
175{
176 switch(dmanr) {
177 case 0:
178 dma_outb(pagenr, DMA_PAGE_0);
179 break;
180 case 1:
181 dma_outb(pagenr, DMA_PAGE_1);
182 break;
183 case 2:
184 dma_outb(pagenr, DMA_PAGE_2);
185 break;
186 case 3:
187 dma_outb(pagenr, DMA_PAGE_3);
188 break;
189 case 5:
190 dma_outb(pagenr & 0xfe, DMA_PAGE_5);
191 break;
192 case 6:
193 dma_outb(pagenr & 0xfe, DMA_PAGE_6);
194 break;
195 case 7:
196 dma_outb(pagenr & 0xfe, DMA_PAGE_7);
197 break;
198 }
199}
200
201
202/* Set transfer address & page bits for specific DMA channel.
203 * Assumes dma flipflop is clear.
204 */
205static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a)
206{
207 set_dma_page(dmanr, (char)(a>>16));
208 if (dmanr <= 3) {
209 dma_outb( a & 0xff, (char)((dmanr&3)<<1) + IO_DMA1_BASE );
210 dma_outb( (a>>8) & 0xff, (char)((dmanr&3)<<1) + IO_DMA1_BASE );
211 } else {
212 dma_outb( (a>>1) & 0xff, (char)((dmanr&3)<<2) + IO_DMA2_BASE );
213 dma_outb( (a>>9) & 0xff, (char)((dmanr&3)<<2) + IO_DMA2_BASE );
214 }
215}
216
217
218/* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for
219 * a specific DMA channel.
220 * You must ensure the parameters are valid.
221 * NOTE: from a manual: "the number of transfers is one more
222 * than the initial word count"! This is taken into account.
223 * Assumes dma flip-flop is clear.
224 * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7.
225 */
226static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count)
227{
228 count--;
229 if (dmanr <= 3) {
230 dma_outb( count & 0xff, (char)((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
231 dma_outb( (count>>8) & 0xff, (char)((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
232 } else {
233 dma_outb( (count>>1) & 0xff, (char)((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
234 dma_outb( (count>>9) & 0xff, (char)((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
235 }
236}
237
238
239/* Get DMA residue count. After a DMA transfer, this
240 * should return zero. Reading this while a DMA transfer is
241 * still in progress will return unpredictable results.
242 * If called before the channel has been used, it may return 1.
243 * Otherwise, it returns the number of _bytes_ left to transfer.
244 *
245 * Assumes DMA flip-flop is clear.
246 */
247static __inline__ int get_dma_residue(unsigned int dmanr)
248{
249 unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE
250 : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE;
251
252 /* using short to get 16-bit wrap around */
253 unsigned short count;
254
255 count = 1 + dma_inb(io_port);
256 count += dma_inb(io_port) << 8;
257
258 return (dmanr<=3)? count : (count<<1);
259}
260
261
262/* These are in kernel/dma.c: */
263extern int request_dma(unsigned int dmanr, const char * device_id); /* reserve a DMA channel */
264extern void free_dma(unsigned int dmanr); /* release it again */
265
266/* From PCI */
267
268#ifdef CONFIG_PCI
269extern int isa_dma_bridge_buggy;
270#else
271#define isa_dma_bridge_buggy (0)
272#endif
273
274#endif /* _ASM_DMA_H */
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