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Andi Kleen5c0f80f2006-06-26 13:57:04 +02001/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/spinlock.h> /* And spinlocks */
12#include <asm/io.h> /* need byte IO */
13#include <linux/delay.h>
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
Andi Kleena2f1b422005-11-05 17:25:53 +010074
75/* 16MB ISA DMA zone */
76#define MAX_DMA_PFN ((16*1024*1024) >> PAGE_SHIFT)
77
78/* 4GB broken PCI/AGP hardware bus master zone */
79#define MAX_DMA32_PFN ((4UL*1024*1024*1024) >> PAGE_SHIFT)
80
81/* Compat define for old dma zone */
82#define MAX_DMA_ADDRESS ((unsigned long)__va(MAX_DMA_PFN << PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -070083
84/* 8237 DMA controllers */
85#define IO_DMA1_BASE 0x00 /* 8 bit slave DMA, channels 0..3 */
86#define IO_DMA2_BASE 0xC0 /* 16 bit master DMA, ch 4(=slave input)..7 */
87
88/* DMA controller registers */
89#define DMA1_CMD_REG 0x08 /* command register (w) */
90#define DMA1_STAT_REG 0x08 /* status register (r) */
91#define DMA1_REQ_REG 0x09 /* request register (w) */
92#define DMA1_MASK_REG 0x0A /* single-channel mask (w) */
93#define DMA1_MODE_REG 0x0B /* mode register (w) */
94#define DMA1_CLEAR_FF_REG 0x0C /* clear pointer flip-flop (w) */
95#define DMA1_TEMP_REG 0x0D /* Temporary Register (r) */
96#define DMA1_RESET_REG 0x0D /* Master Clear (w) */
97#define DMA1_CLR_MASK_REG 0x0E /* Clear Mask */
98#define DMA1_MASK_ALL_REG 0x0F /* all-channels mask (w) */
99
100#define DMA2_CMD_REG 0xD0 /* command register (w) */
101#define DMA2_STAT_REG 0xD0 /* status register (r) */
102#define DMA2_REQ_REG 0xD2 /* request register (w) */
103#define DMA2_MASK_REG 0xD4 /* single-channel mask (w) */
104#define DMA2_MODE_REG 0xD6 /* mode register (w) */
105#define DMA2_CLEAR_FF_REG 0xD8 /* clear pointer flip-flop (w) */
106#define DMA2_TEMP_REG 0xDA /* Temporary Register (r) */
107#define DMA2_RESET_REG 0xDA /* Master Clear (w) */
108#define DMA2_CLR_MASK_REG 0xDC /* Clear Mask */
109#define DMA2_MASK_ALL_REG 0xDE /* all-channels mask (w) */
110
111#define DMA_ADDR_0 0x00 /* DMA address registers */
112#define DMA_ADDR_1 0x02
113#define DMA_ADDR_2 0x04
114#define DMA_ADDR_3 0x06
115#define DMA_ADDR_4 0xC0
116#define DMA_ADDR_5 0xC4
117#define DMA_ADDR_6 0xC8
118#define DMA_ADDR_7 0xCC
119
120#define DMA_CNT_0 0x01 /* DMA count registers */
121#define DMA_CNT_1 0x03
122#define DMA_CNT_2 0x05
123#define DMA_CNT_3 0x07
124#define DMA_CNT_4 0xC2
125#define DMA_CNT_5 0xC6
126#define DMA_CNT_6 0xCA
127#define DMA_CNT_7 0xCE
128
129#define DMA_PAGE_0 0x87 /* DMA page registers */
130#define DMA_PAGE_1 0x83
131#define DMA_PAGE_2 0x81
132#define DMA_PAGE_3 0x82
133#define DMA_PAGE_5 0x8B
134#define DMA_PAGE_6 0x89
135#define DMA_PAGE_7 0x8A
136
137#define DMA_MODE_READ 0x44 /* I/O to memory, no autoinit, increment, single mode */
138#define DMA_MODE_WRITE 0x48 /* memory to I/O, no autoinit, increment, single mode */
139#define DMA_MODE_CASCADE 0xC0 /* pass thru DREQ->HRQ, DACK<-HLDA only */
140
141#define DMA_AUTOINIT 0x10
142
143
144extern spinlock_t dma_spin_lock;
145
146static __inline__ unsigned long claim_dma_lock(void)
147{
148 unsigned long flags;
149 spin_lock_irqsave(&dma_spin_lock, flags);
150 return flags;
151}
152
153static __inline__ void release_dma_lock(unsigned long flags)
154{
155 spin_unlock_irqrestore(&dma_spin_lock, flags);
156}
157
158/* enable/disable a specific DMA channel */
159static __inline__ void enable_dma(unsigned int dmanr)
160{
161 if (dmanr<=3)
162 dma_outb(dmanr, DMA1_MASK_REG);
163 else
164 dma_outb(dmanr & 3, DMA2_MASK_REG);
165}
166
167static __inline__ void disable_dma(unsigned int dmanr)
168{
169 if (dmanr<=3)
170 dma_outb(dmanr | 4, DMA1_MASK_REG);
171 else
172 dma_outb((dmanr & 3) | 4, DMA2_MASK_REG);
173}
174
175/* Clear the 'DMA Pointer Flip Flop'.
176 * Write 0 for LSB/MSB, 1 for MSB/LSB access.
177 * Use this once to initialize the FF to a known state.
178 * After that, keep track of it. :-)
179 * --- In order to do that, the DMA routines below should ---
180 * --- only be used while holding the DMA lock ! ---
181 */
182static __inline__ void clear_dma_ff(unsigned int dmanr)
183{
184 if (dmanr<=3)
185 dma_outb(0, DMA1_CLEAR_FF_REG);
186 else
187 dma_outb(0, DMA2_CLEAR_FF_REG);
188}
189
190/* set mode (above) for a specific DMA channel */
191static __inline__ void set_dma_mode(unsigned int dmanr, char mode)
192{
193 if (dmanr<=3)
194 dma_outb(mode | dmanr, DMA1_MODE_REG);
195 else
196 dma_outb(mode | (dmanr&3), DMA2_MODE_REG);
197}
198
199/* Set only the page register bits of the transfer address.
200 * This is used for successive transfers when we know the contents of
201 * the lower 16 bits of the DMA current address register, but a 64k boundary
202 * may have been crossed.
203 */
204static __inline__ void set_dma_page(unsigned int dmanr, char pagenr)
205{
206 switch(dmanr) {
207 case 0:
208 dma_outb(pagenr, DMA_PAGE_0);
209 break;
210 case 1:
211 dma_outb(pagenr, DMA_PAGE_1);
212 break;
213 case 2:
214 dma_outb(pagenr, DMA_PAGE_2);
215 break;
216 case 3:
217 dma_outb(pagenr, DMA_PAGE_3);
218 break;
219 case 5:
220 dma_outb(pagenr & 0xfe, DMA_PAGE_5);
221 break;
222 case 6:
223 dma_outb(pagenr & 0xfe, DMA_PAGE_6);
224 break;
225 case 7:
226 dma_outb(pagenr & 0xfe, DMA_PAGE_7);
227 break;
228 }
229}
230
231
232/* Set transfer address & page bits for specific DMA channel.
233 * Assumes dma flipflop is clear.
234 */
235static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a)
236{
237 set_dma_page(dmanr, a>>16);
238 if (dmanr <= 3) {
239 dma_outb( a & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
240 dma_outb( (a>>8) & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
241 } else {
242 dma_outb( (a>>1) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
243 dma_outb( (a>>9) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
244 }
245}
246
247
248/* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for
249 * a specific DMA channel.
250 * You must ensure the parameters are valid.
251 * NOTE: from a manual: "the number of transfers is one more
252 * than the initial word count"! This is taken into account.
253 * Assumes dma flip-flop is clear.
254 * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7.
255 */
256static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count)
257{
258 count--;
259 if (dmanr <= 3) {
260 dma_outb( count & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
261 dma_outb( (count>>8) & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
262 } else {
263 dma_outb( (count>>1) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
264 dma_outb( (count>>9) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
265 }
266}
267
268
269/* Get DMA residue count. After a DMA transfer, this
270 * should return zero. Reading this while a DMA transfer is
271 * still in progress will return unpredictable results.
272 * If called before the channel has been used, it may return 1.
273 * Otherwise, it returns the number of _bytes_ left to transfer.
274 *
275 * Assumes DMA flip-flop is clear.
276 */
277static __inline__ int get_dma_residue(unsigned int dmanr)
278{
279 unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE
280 : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE;
281
282 /* using short to get 16-bit wrap around */
283 unsigned short count;
284
285 count = 1 + dma_inb(io_port);
286 count += dma_inb(io_port) << 8;
287
288 return (dmanr<=3)? count : (count<<1);
289}
290
291
292/* These are in kernel/dma.c: */
293extern int request_dma(unsigned int dmanr, const char * device_id); /* reserve a DMA channel */
294extern void free_dma(unsigned int dmanr); /* release it again */
295
296/* From PCI */
297
298#ifdef CONFIG_PCI
299extern int isa_dma_bridge_buggy;
300#else
301#define isa_dma_bridge_buggy (0)
302#endif
303
304#endif /* _ASM_DMA_H */