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Linux kernel mirror (for testing)
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linux
1/*
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 * Changes for ppc sound by Christoph Nadig
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 */
13
14#ifndef _ASM_DMA_H
15#define _ASM_DMA_H
16
17#include <linux/config.h>
18#include <asm/io.h>
19#include <linux/spinlock.h>
20#include <asm/system.h>
21
22#ifndef MAX_DMA_CHANNELS
23#define MAX_DMA_CHANNELS 8
24#endif
25
26/* The maximum address that we can perform a DMA transfer to on this platform */
27/* Doesn't really apply... */
28#define MAX_DMA_ADDRESS (~0UL)
29
30#if !defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI)
31
32#define dma_outb outb
33#define dma_inb inb
34
35/*
36 * NOTES about DMA transfers:
37 *
38 * controller 1: channels 0-3, byte operations, ports 00-1F
39 * controller 2: channels 4-7, word operations, ports C0-DF
40 *
41 * - ALL registers are 8 bits only, regardless of transfer size
42 * - channel 4 is not used - cascades 1 into 2.
43 * - channels 0-3 are byte - addresses/counts are for physical bytes
44 * - channels 5-7 are word - addresses/counts are for physical words
45 * - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries
46 * - transfer count loaded to registers is 1 less than actual count
47 * - controller 2 offsets are all even (2x offsets for controller 1)
48 * - page registers for 5-7 don't use data bit 0, represent 128K pages
49 * - page registers for 0-3 use bit 0, represent 64K pages
50 *
51 * On PReP, DMA transfers are limited to the lower 16MB of _physical_ memory.
52 * On CHRP, the W83C553F (and VLSI Tollgate?) support full 32 bit addressing.
53 * Note that addresses loaded into registers must be _physical_ addresses,
54 * not logical addresses (which may differ if paging is active).
55 *
56 * Address mapping for channels 0-3:
57 *
58 * A23 ... A16 A15 ... A8 A7 ... A0 (Physical addresses)
59 * | ... | | ... | | ... |
60 * | ... | | ... | | ... |
61 * | ... | | ... | | ... |
62 * P7 ... P0 A7 ... A0 A7 ... A0
63 * | Page | Addr MSB | Addr LSB | (DMA registers)
64 *
65 * Address mapping for channels 5-7:
66 *
67 * A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0 (Physical addresses)
68 * | ... | \ \ ... \ \ \ ... \ \
69 * | ... | \ \ ... \ \ \ ... \ (not used)
70 * | ... | \ \ ... \ \ \ ... \
71 * P7 ... P1 (0) A7 A6 ... A0 A7 A6 ... A0
72 * | Page | Addr MSB | Addr LSB | (DMA registers)
73 *
74 * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses
75 * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at
76 * the hardware level, so odd-byte transfers aren't possible).
77 *
78 * Transfer count (_not # bytes_) is limited to 64K, represented as actual
79 * count - 1 : 64K => 0xFFFF, 1 => 0x0000. Thus, count is always 1 or more,
80 * and up to 128K bytes may be transferred on channels 5-7 in one operation.
81 *
82 */
83
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_LO_PAGE_0 0x87 /* DMA page registers */
130#define DMA_LO_PAGE_1 0x83
131#define DMA_LO_PAGE_2 0x81
132#define DMA_LO_PAGE_3 0x82
133#define DMA_LO_PAGE_5 0x8B
134#define DMA_LO_PAGE_6 0x89
135#define DMA_LO_PAGE_7 0x8A
136
137#define DMA_HI_PAGE_0 0x487 /* DMA page registers */
138#define DMA_HI_PAGE_1 0x483
139#define DMA_HI_PAGE_2 0x481
140#define DMA_HI_PAGE_3 0x482
141#define DMA_HI_PAGE_5 0x48B
142#define DMA_HI_PAGE_6 0x489
143#define DMA_HI_PAGE_7 0x48A
144
145#define DMA1_EXT_REG 0x40B
146#define DMA2_EXT_REG 0x4D6
147
148#define DMA_MODE_READ 0x44 /* I/O to memory, no autoinit, increment, single mode */
149#define DMA_MODE_WRITE 0x48 /* memory to I/O, no autoinit, increment, single mode */
150#define DMA_MODE_CASCADE 0xC0 /* pass thru DREQ->HRQ, DACK<-HLDA only */
151
152#define DMA_AUTOINIT 0x10
153
154extern spinlock_t dma_spin_lock;
155
156static __inline__ unsigned long claim_dma_lock(void)
157{
158 unsigned long flags;
159 spin_lock_irqsave(&dma_spin_lock, flags);
160 return flags;
161}
162
163static __inline__ void release_dma_lock(unsigned long flags)
164{
165 spin_unlock_irqrestore(&dma_spin_lock, flags);
166}
167
168/* enable/disable a specific DMA channel */
169static __inline__ void enable_dma(unsigned int dmanr)
170{
171 unsigned char ucDmaCmd=0x00;
172
173 if (dmanr != 4)
174 {
175 dma_outb(0, DMA2_MASK_REG); /* This may not be enabled */
176 dma_outb(ucDmaCmd, DMA2_CMD_REG); /* Enable group */
177 }
178 if (dmanr<=3)
179 {
180 dma_outb(dmanr, DMA1_MASK_REG);
181 dma_outb(ucDmaCmd, DMA1_CMD_REG); /* Enable group */
182 } else
183 {
184 dma_outb(dmanr & 3, DMA2_MASK_REG);
185 }
186}
187
188static __inline__ void disable_dma(unsigned int dmanr)
189{
190 if (dmanr<=3)
191 dma_outb(dmanr | 4, DMA1_MASK_REG);
192 else
193 dma_outb((dmanr & 3) | 4, DMA2_MASK_REG);
194}
195
196/* Clear the 'DMA Pointer Flip Flop'.
197 * Write 0 for LSB/MSB, 1 for MSB/LSB access.
198 * Use this once to initialize the FF to a known state.
199 * After that, keep track of it. :-)
200 * --- In order to do that, the DMA routines below should ---
201 * --- only be used while interrupts are disabled! ---
202 */
203static __inline__ void clear_dma_ff(unsigned int dmanr)
204{
205 if (dmanr<=3)
206 dma_outb(0, DMA1_CLEAR_FF_REG);
207 else
208 dma_outb(0, DMA2_CLEAR_FF_REG);
209}
210
211/* set mode (above) for a specific DMA channel */
212static __inline__ void set_dma_mode(unsigned int dmanr, char mode)
213{
214 if (dmanr<=3)
215 dma_outb(mode | dmanr, DMA1_MODE_REG);
216 else
217 dma_outb(mode | (dmanr&3), DMA2_MODE_REG);
218}
219
220/* Set only the page register bits of the transfer address.
221 * This is used for successive transfers when we know the contents of
222 * the lower 16 bits of the DMA current address register, but a 64k boundary
223 * may have been crossed.
224 */
225static __inline__ void set_dma_page(unsigned int dmanr, int pagenr)
226{
227 switch(dmanr) {
228 case 0:
229 dma_outb(pagenr, DMA_LO_PAGE_0);
230 dma_outb(pagenr>>8, DMA_HI_PAGE_0);
231 break;
232 case 1:
233 dma_outb(pagenr, DMA_LO_PAGE_1);
234 dma_outb(pagenr>>8, DMA_HI_PAGE_1);
235 break;
236 case 2:
237 dma_outb(pagenr, DMA_LO_PAGE_2);
238 dma_outb(pagenr>>8, DMA_HI_PAGE_2);
239 break;
240 case 3:
241 dma_outb(pagenr, DMA_LO_PAGE_3);
242 dma_outb(pagenr>>8, DMA_HI_PAGE_3);
243 break;
244 case 5:
245 dma_outb(pagenr & 0xfe, DMA_LO_PAGE_5);
246 dma_outb(pagenr>>8, DMA_HI_PAGE_5);
247 break;
248 case 6:
249 dma_outb(pagenr & 0xfe, DMA_LO_PAGE_6);
250 dma_outb(pagenr>>8, DMA_HI_PAGE_6);
251 break;
252 case 7:
253 dma_outb(pagenr & 0xfe, DMA_LO_PAGE_7);
254 dma_outb(pagenr>>8, DMA_HI_PAGE_7);
255 break;
256 }
257}
258
259
260/* Set transfer address & page bits for specific DMA channel.
261 * Assumes dma flipflop is clear.
262 */
263static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int phys)
264{
265 if (dmanr <= 3) {
266 dma_outb( phys & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
267 dma_outb( (phys>>8) & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
268 } else {
269 dma_outb( (phys>>1) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
270 dma_outb( (phys>>9) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
271 }
272 set_dma_page(dmanr, phys>>16);
273}
274
275
276/* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for
277 * a specific DMA channel.
278 * You must ensure the parameters are valid.
279 * NOTE: from a manual: "the number of transfers is one more
280 * than the initial word count"! This is taken into account.
281 * Assumes dma flip-flop is clear.
282 * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7.
283 */
284static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count)
285{
286 count--;
287 if (dmanr <= 3) {
288 dma_outb( count & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
289 dma_outb( (count>>8) & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
290 } else {
291 dma_outb( (count>>1) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
292 dma_outb( (count>>9) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
293 }
294}
295
296
297/* Get DMA residue count. After a DMA transfer, this
298 * should return zero. Reading this while a DMA transfer is
299 * still in progress will return unpredictable results.
300 * If called before the channel has been used, it may return 1.
301 * Otherwise, it returns the number of _bytes_ left to transfer.
302 *
303 * Assumes DMA flip-flop is clear.
304 */
305static __inline__ int get_dma_residue(unsigned int dmanr)
306{
307 unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE
308 : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE;
309
310 /* using short to get 16-bit wrap around */
311 unsigned short count;
312
313 count = 1 + dma_inb(io_port);
314 count += dma_inb(io_port) << 8;
315
316 return (dmanr <= 3)? count : (count<<1);
317}
318
319/* These are in kernel/dma.c: */
320extern int request_dma(unsigned int dmanr, const char * device_id); /* reserve a DMA channel */
321extern void free_dma(unsigned int dmanr); /* release it again */
322
323#ifdef CONFIG_PCI
324extern int isa_dma_bridge_buggy;
325#else
326#define isa_dma_bridge_buggy (0)
327#endif
328#endif /* !defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI) */
329#endif /* _ASM_DMA_H */