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1da177e4 LT |
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 <linux/config.h> | |
16 | #include <asm/io.h> /* need byte IO */ | |
17 | #include <linux/spinlock.h> /* And spinlocks */ | |
18 | #include <linux/delay.h> | |
19 | #include <asm/system.h> | |
20 | ||
21 | ||
22 | #ifdef HAVE_REALLY_SLOW_DMA_CONTROLLER | |
23 | #define dma_outb outb_p | |
24 | #else | |
25 | #define dma_outb outb | |
26 | #endif | |
27 | ||
28 | #define dma_inb inb | |
29 | ||
30 | /* | |
31 | * NOTES about DMA transfers: | |
32 | * | |
33 | * controller 1: channels 0-3, byte operations, ports 00-1F | |
34 | * controller 2: channels 4-7, word operations, ports C0-DF | |
35 | * | |
36 | * - ALL registers are 8 bits only, regardless of transfer size | |
37 | * - channel 4 is not used - cascades 1 into 2. | |
38 | * - channels 0-3 are byte - addresses/counts are for physical bytes | |
39 | * - channels 5-7 are word - addresses/counts are for physical words | |
40 | * - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries | |
41 | * - transfer count loaded to registers is 1 less than actual count | |
42 | * - controller 2 offsets are all even (2x offsets for controller 1) | |
43 | * - page registers for 5-7 don't use data bit 0, represent 128K pages | |
44 | * - page registers for 0-3 use bit 0, represent 64K pages | |
45 | * | |
46 | * DMA transfers are limited to the lower 16MB of _physical_ memory. | |
47 | * Note that addresses loaded into registers must be _physical_ addresses, | |
48 | * not logical addresses (which may differ if paging is active). | |
49 | * | |
50 | * Address mapping for channels 0-3: | |
51 | * | |
52 | * A23 ... A16 A15 ... A8 A7 ... A0 (Physical addresses) | |
53 | * | ... | | ... | | ... | | |
54 | * | ... | | ... | | ... | | |
55 | * | ... | | ... | | ... | | |
56 | * P7 ... P0 A7 ... A0 A7 ... A0 | |
57 | * | Page | Addr MSB | Addr LSB | (DMA registers) | |
58 | * | |
59 | * Address mapping for channels 5-7: | |
60 | * | |
61 | * A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0 (Physical addresses) | |
62 | * | ... | \ \ ... \ \ \ ... \ \ | |
63 | * | ... | \ \ ... \ \ \ ... \ (not used) | |
64 | * | ... | \ \ ... \ \ \ ... \ | |
65 | * P7 ... P1 (0) A7 A6 ... A0 A7 A6 ... A0 | |
66 | * | Page | Addr MSB | Addr LSB | (DMA registers) | |
67 | * | |
68 | * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses | |
69 | * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at | |
70 | * the hardware level, so odd-byte transfers aren't possible). | |
71 | * | |
72 | * Transfer count (_not # bytes_) is limited to 64K, represented as actual | |
73 | * count - 1 : 64K => 0xFFFF, 1 => 0x0000. Thus, count is always 1 or more, | |
74 | * and up to 128K bytes may be transferred on channels 5-7 in one operation. | |
75 | * | |
76 | */ | |
77 | ||
78 | #define MAX_DMA_CHANNELS 8 | |
79 | ||
80 | /* | |
81 | * The maximum address in KSEG0 that we can perform a DMA transfer to on this | |
82 | * platform. This describes only the PC style part of the DMA logic like on | |
83 | * Deskstations or Acer PICA but not the much more versatile DMA logic used | |
84 | * for the local devices on Acer PICA or Magnums. | |
85 | */ | |
86 | #ifdef CONFIG_SGI_IP22 | |
87 | /* Horrible hack to have a correct DMA window on IP22 */ | |
88 | #include <asm/sgi/mc.h> | |
89 | #define MAX_DMA_ADDRESS (PAGE_OFFSET + SGIMC_SEG0_BADDR + 0x01000000) | |
90 | #else | |
91 | #define MAX_DMA_ADDRESS (PAGE_OFFSET + 0x01000000) | |
92 | #endif | |
93 | ||
94 | /* 8237 DMA controllers */ | |
95 | #define IO_DMA1_BASE 0x00 /* 8 bit slave DMA, channels 0..3 */ | |
96 | #define IO_DMA2_BASE 0xC0 /* 16 bit master DMA, ch 4(=slave input)..7 */ | |
97 | ||
98 | /* DMA controller registers */ | |
99 | #define DMA1_CMD_REG 0x08 /* command register (w) */ | |
100 | #define DMA1_STAT_REG 0x08 /* status register (r) */ | |
101 | #define DMA1_REQ_REG 0x09 /* request register (w) */ | |
102 | #define DMA1_MASK_REG 0x0A /* single-channel mask (w) */ | |
103 | #define DMA1_MODE_REG 0x0B /* mode register (w) */ | |
104 | #define DMA1_CLEAR_FF_REG 0x0C /* clear pointer flip-flop (w) */ | |
105 | #define DMA1_TEMP_REG 0x0D /* Temporary Register (r) */ | |
106 | #define DMA1_RESET_REG 0x0D /* Master Clear (w) */ | |
107 | #define DMA1_CLR_MASK_REG 0x0E /* Clear Mask */ | |
108 | #define DMA1_MASK_ALL_REG 0x0F /* all-channels mask (w) */ | |
109 | ||
110 | #define DMA2_CMD_REG 0xD0 /* command register (w) */ | |
111 | #define DMA2_STAT_REG 0xD0 /* status register (r) */ | |
112 | #define DMA2_REQ_REG 0xD2 /* request register (w) */ | |
113 | #define DMA2_MASK_REG 0xD4 /* single-channel mask (w) */ | |
114 | #define DMA2_MODE_REG 0xD6 /* mode register (w) */ | |
115 | #define DMA2_CLEAR_FF_REG 0xD8 /* clear pointer flip-flop (w) */ | |
116 | #define DMA2_TEMP_REG 0xDA /* Temporary Register (r) */ | |
117 | #define DMA2_RESET_REG 0xDA /* Master Clear (w) */ | |
118 | #define DMA2_CLR_MASK_REG 0xDC /* Clear Mask */ | |
119 | #define DMA2_MASK_ALL_REG 0xDE /* all-channels mask (w) */ | |
120 | ||
121 | #define DMA_ADDR_0 0x00 /* DMA address registers */ | |
122 | #define DMA_ADDR_1 0x02 | |
123 | #define DMA_ADDR_2 0x04 | |
124 | #define DMA_ADDR_3 0x06 | |
125 | #define DMA_ADDR_4 0xC0 | |
126 | #define DMA_ADDR_5 0xC4 | |
127 | #define DMA_ADDR_6 0xC8 | |
128 | #define DMA_ADDR_7 0xCC | |
129 | ||
130 | #define DMA_CNT_0 0x01 /* DMA count registers */ | |
131 | #define DMA_CNT_1 0x03 | |
132 | #define DMA_CNT_2 0x05 | |
133 | #define DMA_CNT_3 0x07 | |
134 | #define DMA_CNT_4 0xC2 | |
135 | #define DMA_CNT_5 0xC6 | |
136 | #define DMA_CNT_6 0xCA | |
137 | #define DMA_CNT_7 0xCE | |
138 | ||
139 | #define DMA_PAGE_0 0x87 /* DMA page registers */ | |
140 | #define DMA_PAGE_1 0x83 | |
141 | #define DMA_PAGE_2 0x81 | |
142 | #define DMA_PAGE_3 0x82 | |
143 | #define DMA_PAGE_5 0x8B | |
144 | #define DMA_PAGE_6 0x89 | |
145 | #define DMA_PAGE_7 0x8A | |
146 | ||
147 | #define DMA_MODE_READ 0x44 /* I/O to memory, no autoinit, increment, single mode */ | |
148 | #define DMA_MODE_WRITE 0x48 /* memory to I/O, no autoinit, increment, single mode */ | |
149 | #define DMA_MODE_CASCADE 0xC0 /* pass thru DREQ->HRQ, DACK<-HLDA only */ | |
150 | ||
151 | #define DMA_AUTOINIT 0x10 | |
152 | ||
153 | extern spinlock_t dma_spin_lock; | |
154 | ||
155 | static __inline__ unsigned long claim_dma_lock(void) | |
156 | { | |
157 | unsigned long flags; | |
158 | spin_lock_irqsave(&dma_spin_lock, flags); | |
159 | return flags; | |
160 | } | |
161 | ||
162 | static __inline__ void release_dma_lock(unsigned long flags) | |
163 | { | |
164 | spin_unlock_irqrestore(&dma_spin_lock, flags); | |
165 | } | |
166 | ||
167 | /* enable/disable a specific DMA channel */ | |
168 | static __inline__ void enable_dma(unsigned int dmanr) | |
169 | { | |
170 | if (dmanr<=3) | |
171 | dma_outb(dmanr, DMA1_MASK_REG); | |
172 | else | |
173 | dma_outb(dmanr & 3, DMA2_MASK_REG); | |
174 | } | |
175 | ||
176 | static __inline__ void disable_dma(unsigned int dmanr) | |
177 | { | |
178 | if (dmanr<=3) | |
179 | dma_outb(dmanr | 4, DMA1_MASK_REG); | |
180 | else | |
181 | dma_outb((dmanr & 3) | 4, DMA2_MASK_REG); | |
182 | } | |
183 | ||
184 | /* Clear the 'DMA Pointer Flip Flop'. | |
185 | * Write 0 for LSB/MSB, 1 for MSB/LSB access. | |
186 | * Use this once to initialize the FF to a known state. | |
187 | * After that, keep track of it. :-) | |
188 | * --- In order to do that, the DMA routines below should --- | |
189 | * --- only be used while holding the DMA lock ! --- | |
190 | */ | |
191 | static __inline__ void clear_dma_ff(unsigned int dmanr) | |
192 | { | |
193 | if (dmanr<=3) | |
194 | dma_outb(0, DMA1_CLEAR_FF_REG); | |
195 | else | |
196 | dma_outb(0, DMA2_CLEAR_FF_REG); | |
197 | } | |
198 | ||
199 | /* set mode (above) for a specific DMA channel */ | |
200 | static __inline__ void set_dma_mode(unsigned int dmanr, char mode) | |
201 | { | |
202 | if (dmanr<=3) | |
203 | dma_outb(mode | dmanr, DMA1_MODE_REG); | |
204 | else | |
205 | dma_outb(mode | (dmanr&3), DMA2_MODE_REG); | |
206 | } | |
207 | ||
208 | /* Set only the page register bits of the transfer address. | |
209 | * This is used for successive transfers when we know the contents of | |
210 | * the lower 16 bits of the DMA current address register, but a 64k boundary | |
211 | * may have been crossed. | |
212 | */ | |
213 | static __inline__ void set_dma_page(unsigned int dmanr, char pagenr) | |
214 | { | |
215 | switch(dmanr) { | |
216 | case 0: | |
217 | dma_outb(pagenr, DMA_PAGE_0); | |
218 | break; | |
219 | case 1: | |
220 | dma_outb(pagenr, DMA_PAGE_1); | |
221 | break; | |
222 | case 2: | |
223 | dma_outb(pagenr, DMA_PAGE_2); | |
224 | break; | |
225 | case 3: | |
226 | dma_outb(pagenr, DMA_PAGE_3); | |
227 | break; | |
228 | case 5: | |
229 | dma_outb(pagenr & 0xfe, DMA_PAGE_5); | |
230 | break; | |
231 | case 6: | |
232 | dma_outb(pagenr & 0xfe, DMA_PAGE_6); | |
233 | break; | |
234 | case 7: | |
235 | dma_outb(pagenr & 0xfe, DMA_PAGE_7); | |
236 | break; | |
237 | } | |
238 | } | |
239 | ||
240 | ||
241 | /* Set transfer address & page bits for specific DMA channel. | |
242 | * Assumes dma flipflop is clear. | |
243 | */ | |
244 | static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a) | |
245 | { | |
246 | set_dma_page(dmanr, a>>16); | |
247 | if (dmanr <= 3) { | |
248 | dma_outb( a & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE ); | |
249 | dma_outb( (a>>8) & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE ); | |
250 | } else { | |
251 | dma_outb( (a>>1) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE ); | |
252 | dma_outb( (a>>9) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE ); | |
253 | } | |
254 | } | |
255 | ||
256 | ||
257 | /* Set transfer size (max 64k for DMA0..3, 128k for DMA5..7) for | |
258 | * a specific DMA channel. | |
259 | * You must ensure the parameters are valid. | |
260 | * NOTE: from a manual: "the number of transfers is one more | |
261 | * than the initial word count"! This is taken into account. | |
262 | * Assumes dma flip-flop is clear. | |
263 | * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7. | |
264 | */ | |
265 | static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count) | |
266 | { | |
267 | count--; | |
268 | if (dmanr <= 3) { | |
269 | dma_outb( count & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE ); | |
270 | dma_outb( (count>>8) & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE ); | |
271 | } else { | |
272 | dma_outb( (count>>1) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE ); | |
273 | dma_outb( (count>>9) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE ); | |
274 | } | |
275 | } | |
276 | ||
277 | ||
278 | /* Get DMA residue count. After a DMA transfer, this | |
279 | * should return zero. Reading this while a DMA transfer is | |
280 | * still in progress will return unpredictable results. | |
281 | * If called before the channel has been used, it may return 1. | |
282 | * Otherwise, it returns the number of _bytes_ left to transfer. | |
283 | * | |
284 | * Assumes DMA flip-flop is clear. | |
285 | */ | |
286 | static __inline__ int get_dma_residue(unsigned int dmanr) | |
287 | { | |
288 | unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE | |
289 | : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE; | |
290 | ||
291 | /* using short to get 16-bit wrap around */ | |
292 | unsigned short count; | |
293 | ||
294 | count = 1 + dma_inb(io_port); | |
295 | count += dma_inb(io_port) << 8; | |
296 | ||
297 | return (dmanr<=3)? count : (count<<1); | |
298 | } | |
299 | ||
300 | ||
301 | /* These are in kernel/dma.c: */ | |
302 | extern int request_dma(unsigned int dmanr, const char * device_id); /* reserve a DMA channel */ | |
303 | extern void free_dma(unsigned int dmanr); /* release it again */ | |
304 | ||
305 | /* From PCI */ | |
306 | ||
307 | #ifdef CONFIG_PCI | |
308 | extern int isa_dma_bridge_buggy; | |
309 | #else | |
310 | #define isa_dma_bridge_buggy (0) | |
311 | #endif | |
312 | ||
313 | #endif /* _ASM_DMA_H */ |