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-rw-r--r--include/asm-mips/dma.h315
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diff --git a/include/asm-mips/dma.h b/include/asm-mips/dma.h
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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 *
7 * NOTE: all this is true *only* for ISA/EISA expansions on Mips boards
8 * and can only be used for expansion cards. Onboard DMA controllers, such
9 * as the R4030 on Jazz boards behave totally different!
10 */
11
12#ifndef _ASM_DMA_H
13#define _ASM_DMA_H
14
15#include <asm/io.h> /* need byte IO */
16#include <linux/spinlock.h> /* And spinlocks */
17#include <linux/delay.h>
18#include <asm/system.h>
19
20
21#ifdef HAVE_REALLY_SLOW_DMA_CONTROLLER
22#define dma_outb outb_p
23#else
24#define dma_outb outb
25#endif
26
27#define dma_inb inb
28
29/*
30 * NOTES about DMA transfers:
31 *
32 * controller 1: channels 0-3, byte operations, ports 00-1F
33 * controller 2: channels 4-7, word operations, ports C0-DF
34 *
35 * - ALL registers are 8 bits only, regardless of transfer size
36 * - channel 4 is not used - cascades 1 into 2.
37 * - channels 0-3 are byte - addresses/counts are for physical bytes
38 * - channels 5-7 are word - addresses/counts are for physical words
39 * - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries
40 * - transfer count loaded to registers is 1 less than actual count
41 * - controller 2 offsets are all even (2x offsets for controller 1)
42 * - page registers for 5-7 don't use data bit 0, represent 128K pages
43 * - page registers for 0-3 use bit 0, represent 64K pages
44 *
45 * DMA transfers are limited to the lower 16MB of _physical_ memory.
46 * Note that addresses loaded into registers must be _physical_ addresses,
47 * not logical addresses (which may differ if paging is active).
48 *
49 * Address mapping for channels 0-3:
50 *
51 * A23 ... A16 A15 ... A8 A7 ... A0 (Physical addresses)
52 * | ... | | ... | | ... |
53 * | ... | | ... | | ... |
54 * | ... | | ... | | ... |
55 * P7 ... P0 A7 ... A0 A7 ... A0
56 * | Page | Addr MSB | Addr LSB | (DMA registers)
57 *
58 * Address mapping for channels 5-7:
59 *
60 * A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0 (Physical addresses)
61 * | ... | \ \ ... \ \ \ ... \ \
62 * | ... | \ \ ... \ \ \ ... \ (not used)
63 * | ... | \ \ ... \ \ \ ... \
64 * P7 ... P1 (0) A7 A6 ... A0 A7 A6 ... A0
65 * | Page | Addr MSB | Addr LSB | (DMA registers)
66 *
67 * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses
68 * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at
69 * the hardware level, so odd-byte transfers aren't possible).
70 *
71 * Transfer count (_not # bytes_) is limited to 64K, represented as actual
72 * count - 1 : 64K => 0xFFFF, 1 => 0x0000. Thus, count is always 1 or more,
73 * and up to 128K bytes may be transferred on channels 5-7 in one operation.
74 *
75 */
76
77#ifndef CONFIG_GENERIC_ISA_DMA_SUPPORT_BROKEN
78#define MAX_DMA_CHANNELS 8
79#endif
80
81/*
82 * The maximum address in KSEG0 that we can perform a DMA transfer to on this
83 * platform. This describes only the PC style part of the DMA logic like on
84 * Deskstations or Acer PICA but not the much more versatile DMA logic used
85 * for the local devices on Acer PICA or Magnums.
86 */
87#if defined(CONFIG_SGI_IP22) || defined(CONFIG_SGI_IP28)
88/* don't care; ISA bus master won't work, ISA slave DMA supports 32bit addr */
89#define MAX_DMA_ADDRESS PAGE_OFFSET
90#else
91#define MAX_DMA_ADDRESS (PAGE_OFFSET + 0x01000000)
92#endif
93#define MAX_DMA_PFN PFN_DOWN(virt_to_phys((void *)MAX_DMA_ADDRESS))
94#define MAX_DMA32_PFN (1UL << (32 - PAGE_SHIFT))
95
96/* 8237 DMA controllers */
97#define IO_DMA1_BASE 0x00 /* 8 bit slave DMA, channels 0..3 */
98#define IO_DMA2_BASE 0xC0 /* 16 bit master DMA, ch 4(=slave input)..7 */
99
100/* DMA controller registers */
101#define DMA1_CMD_REG 0x08 /* command register (w) */
102#define DMA1_STAT_REG 0x08 /* status register (r) */
103#define DMA1_REQ_REG 0x09 /* request register (w) */
104#define DMA1_MASK_REG 0x0A /* single-channel mask (w) */
105#define DMA1_MODE_REG 0x0B /* mode register (w) */
106#define DMA1_CLEAR_FF_REG 0x0C /* clear pointer flip-flop (w) */
107#define DMA1_TEMP_REG 0x0D /* Temporary Register (r) */
108#define DMA1_RESET_REG 0x0D /* Master Clear (w) */
109#define DMA1_CLR_MASK_REG 0x0E /* Clear Mask */
110#define DMA1_MASK_ALL_REG 0x0F /* all-channels mask (w) */
111
112#define DMA2_CMD_REG 0xD0 /* command register (w) */
113#define DMA2_STAT_REG 0xD0 /* status register (r) */
114#define DMA2_REQ_REG 0xD2 /* request register (w) */
115#define DMA2_MASK_REG 0xD4 /* single-channel mask (w) */
116#define DMA2_MODE_REG 0xD6 /* mode register (w) */
117#define DMA2_CLEAR_FF_REG 0xD8 /* clear pointer flip-flop (w) */
118#define DMA2_TEMP_REG 0xDA /* Temporary Register (r) */
119#define DMA2_RESET_REG 0xDA /* Master Clear (w) */
120#define DMA2_CLR_MASK_REG 0xDC /* Clear Mask */
121#define DMA2_MASK_ALL_REG 0xDE /* all-channels mask (w) */
122
123#define DMA_ADDR_0 0x00 /* DMA address registers */
124#define DMA_ADDR_1 0x02
125#define DMA_ADDR_2 0x04
126#define DMA_ADDR_3 0x06
127#define DMA_ADDR_4 0xC0
128#define DMA_ADDR_5 0xC4
129#define DMA_ADDR_6 0xC8
130#define DMA_ADDR_7 0xCC
131
132#define DMA_CNT_0 0x01 /* DMA count registers */
133#define DMA_CNT_1 0x03
134#define DMA_CNT_2 0x05
135#define DMA_CNT_3 0x07
136#define DMA_CNT_4 0xC2
137#define DMA_CNT_5 0xC6
138#define DMA_CNT_6 0xCA
139#define DMA_CNT_7 0xCE
140
141#define DMA_PAGE_0 0x87 /* DMA page registers */
142#define DMA_PAGE_1 0x83
143#define DMA_PAGE_2 0x81
144#define DMA_PAGE_3 0x82
145#define DMA_PAGE_5 0x8B
146#define DMA_PAGE_6 0x89
147#define DMA_PAGE_7 0x8A
148
149#define DMA_MODE_READ 0x44 /* I/O to memory, no autoinit, increment, single mode */
150#define DMA_MODE_WRITE 0x48 /* memory to I/O, no autoinit, increment, single mode */
151#define DMA_MODE_CASCADE 0xC0 /* pass thru DREQ->HRQ, DACK<-HLDA only */
152
153#define DMA_AUTOINIT 0x10
154
155extern spinlock_t dma_spin_lock;
156
157static __inline__ unsigned long claim_dma_lock(void)
158{
159 unsigned long flags;
160 spin_lock_irqsave(&dma_spin_lock, flags);
161 return flags;
162}
163
164static __inline__ void release_dma_lock(unsigned long flags)
165{
166 spin_unlock_irqrestore(&dma_spin_lock, flags);
167}
168
169/* enable/disable a specific DMA channel */
170static __inline__ void enable_dma(unsigned int dmanr)
171{
172 if (dmanr<=3)
173 dma_outb(dmanr, DMA1_MASK_REG);
174 else
175 dma_outb(dmanr & 3, DMA2_MASK_REG);
176}
177
178static __inline__ void disable_dma(unsigned int dmanr)
179{
180 if (dmanr<=3)
181 dma_outb(dmanr | 4, DMA1_MASK_REG);
182 else
183 dma_outb((dmanr & 3) | 4, DMA2_MASK_REG);
184}
185
186/* Clear the 'DMA Pointer Flip Flop'.
187 * Write 0 for LSB/MSB, 1 for MSB/LSB access.
188 * Use this once to initialize the FF to a known state.
189 * After that, keep track of it. :-)
190 * --- In order to do that, the DMA routines below should ---
191 * --- only be used while holding the DMA lock ! ---
192 */
193static __inline__ void clear_dma_ff(unsigned int dmanr)
194{
195 if (dmanr<=3)
196 dma_outb(0, DMA1_CLEAR_FF_REG);
197 else
198 dma_outb(0, DMA2_CLEAR_FF_REG);
199}
200
201/* set mode (above) for a specific DMA channel */
202static __inline__ void set_dma_mode(unsigned int dmanr, char mode)
203{
204 if (dmanr<=3)
205 dma_outb(mode | dmanr, DMA1_MODE_REG);
206 else
207 dma_outb(mode | (dmanr&3), DMA2_MODE_REG);
208}
209
210/* Set only the page register bits of the transfer address.
211 * This is used for successive transfers when we know the contents of
212 * the lower 16 bits of the DMA current address register, but a 64k boundary
213 * may have been crossed.
214 */
215static __inline__ void set_dma_page(unsigned int dmanr, char pagenr)
216{
217 switch(dmanr) {
218 case 0:
219 dma_outb(pagenr, DMA_PAGE_0);
220 break;
221 case 1:
222 dma_outb(pagenr, DMA_PAGE_1);
223 break;
224 case 2:
225 dma_outb(pagenr, DMA_PAGE_2);
226 break;
227 case 3:
228 dma_outb(pagenr, DMA_PAGE_3);
229 break;
230 case 5:
231 dma_outb(pagenr & 0xfe, DMA_PAGE_5);
232 break;
233 case 6:
234 dma_outb(pagenr & 0xfe, DMA_PAGE_6);
235 break;
236 case 7:
237 dma_outb(pagenr & 0xfe, DMA_PAGE_7);
238 break;
239 }
240}
241
242
243/* Set transfer address & page bits for specific DMA channel.
244 * Assumes dma flipflop is clear.
245 */
246static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a)
247{
248 set_dma_page(dmanr, a>>16);
249 if (dmanr <= 3) {
250 dma_outb( a & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
251 dma_outb( (a>>8) & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
252 } else {
253 dma_outb( (a>>1) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
254 dma_outb( (a>>9) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
255 }
256}
257
258
259/* Set transfer size (max 64k for DMA0..3, 128k for DMA5..7) for
260 * a specific DMA channel.
261 * You must ensure the parameters are valid.
262 * NOTE: from a manual: "the number of transfers is one more
263 * than the initial word count"! This is taken into account.
264 * Assumes dma flip-flop is clear.
265 * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7.
266 */
267static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count)
268{
269 count--;
270 if (dmanr <= 3) {
271 dma_outb( count & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
272 dma_outb( (count>>8) & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
273 } else {
274 dma_outb( (count>>1) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
275 dma_outb( (count>>9) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
276 }
277}
278
279
280/* Get DMA residue count. After a DMA transfer, this
281 * should return zero. Reading this while a DMA transfer is
282 * still in progress will return unpredictable results.
283 * If called before the channel has been used, it may return 1.
284 * Otherwise, it returns the number of _bytes_ left to transfer.
285 *
286 * Assumes DMA flip-flop is clear.
287 */
288static __inline__ int get_dma_residue(unsigned int dmanr)
289{
290 unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE
291 : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE;
292
293 /* using short to get 16-bit wrap around */
294 unsigned short count;
295
296 count = 1 + dma_inb(io_port);
297 count += dma_inb(io_port) << 8;
298
299 return (dmanr<=3)? count : (count<<1);
300}
301
302
303/* These are in kernel/dma.c: */
304extern int request_dma(unsigned int dmanr, const char * device_id); /* reserve a DMA channel */
305extern void free_dma(unsigned int dmanr); /* release it again */
306
307/* From PCI */
308
309#ifdef CONFIG_PCI
310extern int isa_dma_bridge_buggy;
311#else
312#define isa_dma_bridge_buggy (0)
313#endif
314
315#endif /* _ASM_DMA_H */
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