1 /*
2 * include/asm-alpha/dma.h
3 *
4 * This is essentially the same as the i386 DMA stuff, as the AlphaPCs
5 * use ISA-compatible dma. The only extension is support for high-page
6 * registers that allow to set the top 8 bits of a 32-bit DMA address.
7 * This register should be written last when setting up a DMA address
8 * as this will also enable DMA across 64 KB boundaries.
9 */
10
11 /* $Id: dma.h,v 1.7 1992/12/14 00:29:34 root Exp root $
12 * linux/include/asm/dma.h: Defines for using and allocating dma channels.
13 * Written by Hennus Bergman, 1992.
14 * High DMA channel support & info by Hannu Savolainen
15 * and John Boyd, Nov. 1992.
16 */
17
18 #ifndef _ASM_DMA_H
19 #define _ASM_DMA_H
20
21 #include <linux/spinlock.h>
22 #include <asm/io.h>
23
24 #define dma_outb outb
25 #define dma_inb inb
26
27 /*
28 * NOTES about DMA transfers:
29 *
30 * controller 1: channels 0-3, byte operations, ports 00-1F
31 * controller 2: channels 4-7, word operations, ports C0-DF
32 *
33 * - ALL registers are 8 bits only, regardless of transfer size
34 * - channel 4 is not used - cascades 1 into 2.
35 * - channels 0-3 are byte - addresses/counts are for physical bytes
36 * - channels 5-7 are word - addresses/counts are for physical words
37 * - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries
38 * - transfer count loaded to registers is 1 less than actual count
39 * - controller 2 offsets are all even (2x offsets for controller 1)
40 * - page registers for 5-7 don't use data bit 0, represent 128K pages
41 * - page registers for 0-3 use bit 0, represent 64K pages
42 *
43 * DMA transfers are limited to the lower 16MB of _physical_ memory.
44 * Note that addresses loaded into registers must be _physical_ addresses,
45 * not logical addresses (which may differ if paging is active).
46 *
47 * Address mapping for channels 0-3:
48 *
49 * A23 ... A16 A15 ... A8 A7 ... A0 (Physical addresses)
50 * | ... | | ... | | ... |
51 * | ... | | ... | | ... |
52 * | ... | | ... | | ... |
53 * P7 ... P0 A7 ... A0 A7 ... A0
54 * | Page | Addr MSB | Addr LSB | (DMA registers)
55 *
56 * Address mapping for channels 5-7:
57 *
58 * A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0 (Physical addresses)
59 * | ... | \ \ ... \ \ \ ... \ \
60 * | ... | \ \ ... \ \ \ ... \ (not used)
61 * | ... | \ \ ... \ \ \ ... \
62 * P7 ... P1 (0) A7 A6 ... A0 A7 A6 ... A0
63 * | Page | Addr MSB | Addr LSB | (DMA registers)
64 *
65 * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses
66 * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at
67 * the hardware level, so odd-byte transfers aren't possible).
68 *
69 * Transfer count (_not # bytes_) is limited to 64K, represented as actual
70 * count - 1 : 64K => 0xFFFF, 1 => 0x0000. Thus, count is always 1 or more,
71 * and up to 128K bytes may be transferred on channels 5-7 in one operation.
72 *
73 */
74
75 #define MAX_DMA_CHANNELS 8
76
77 /*
78 ISA DMA limitations on Alpha platforms,
79
80 These may be due to SIO (PCI<->ISA bridge) chipset limitation, or
81 just a wiring limit.
82 */
83
84 /* The maximum address for ISA DMA transfer on Alpha XL, due to an
85 hardware SIO limitation, is 64MB.
86 */
87 #define ALPHA_XL_MAX_ISA_DMA_ADDRESS 0x04000000UL
88
89 /* The maximum address for ISA DMA transfer on RUFFIAN,
90 due to an hardware SIO limitation, is 16MB.
91 */
92 #define ALPHA_RUFFIAN_MAX_ISA_DMA_ADDRESS 0x01000000UL
93
94 /* The maximum address for ISA DMA transfer on SABLE, and some ALCORs,
95 due to an hardware SIO chip limitation, is 2GB.
96 */
97 #define ALPHA_SABLE_MAX_ISA_DMA_ADDRESS 0x80000000UL
98 #define ALPHA_ALCOR_MAX_ISA_DMA_ADDRESS 0x80000000UL
99
100 /*
101 Maximum address for all the others is the complete 32-bit bus
102 address space.
103 */
104 #define ALPHA_MAX_ISA_DMA_ADDRESS 0x100000000UL
105
106 #ifdef CONFIG_ALPHA_GENERIC
107 # define MAX_ISA_DMA_ADDRESS (alpha_mv.max_isa_dma_address)
108 #else
109 # if defined(CONFIG_ALPHA_XL)
110 # define MAX_ISA_DMA_ADDRESS ALPHA_XL_MAX_ISA_DMA_ADDRESS
111 # elif defined(CONFIG_ALPHA_RUFFIAN)
112 # define MAX_ISA_DMA_ADDRESS ALPHA_RUFFIAN_MAX_ISA_DMA_ADDRESS
113 # elif defined(CONFIG_ALPHA_SABLE)
114 # define MAX_ISA_DMA_ADDRESS ALPHA_SABLE_MAX_ISA_DMA_ADDRESS
115 # elif defined(CONFIG_ALPHA_ALCOR)
116 # define MAX_ISA_DMA_ADDRESS ALPHA_ALCOR_MAX_ISA_DMA_ADDRESS
117 # else
118 # define MAX_ISA_DMA_ADDRESS ALPHA_MAX_ISA_DMA_ADDRESS
119 # endif
120 #endif
121
122 /* If we have the iommu, we don't have any address limitations on DMA.
123 Otherwise (Nautilus, RX164), we have to have 0-16 Mb DMA zone
124 like i386. */
125 #define MAX_DMA_ADDRESS (alpha_mv.mv_pci_tbi ? \
126 ~0UL : IDENT_ADDR + 0x01000000)
127
128 /* 8237 DMA controllers */
129 #define IO_DMA1_BASE 0x00 /* 8 bit slave DMA, channels 0..3 */
130 #define IO_DMA2_BASE 0xC0 /* 16 bit master DMA, ch 4(=slave input)..7 */
131
132 /* DMA controller registers */
133 #define DMA1_CMD_REG 0x08 /* command register (w) */
134 #define DMA1_STAT_REG 0x08 /* status register (r) */
135 #define DMA1_REQ_REG 0x09 /* request register (w) */
136 #define DMA1_MASK_REG 0x0A /* single-channel mask (w) */
137 #define DMA1_MODE_REG 0x0B /* mode register (w) */
138 #define DMA1_CLEAR_FF_REG 0x0C /* clear pointer flip-flop (w) */
139 #define DMA1_TEMP_REG 0x0D /* Temporary Register (r) */
140 #define DMA1_RESET_REG 0x0D /* Master Clear (w) */
141 #define DMA1_CLR_MASK_REG 0x0E /* Clear Mask */
142 #define DMA1_MASK_ALL_REG 0x0F /* all-channels mask (w) */
143 #define DMA1_EXT_MODE_REG (0x400 | DMA1_MODE_REG)
144
145 #define DMA2_CMD_REG 0xD0 /* command register (w) */
146 #define DMA2_STAT_REG 0xD0 /* status register (r) */
147 #define DMA2_REQ_REG 0xD2 /* request register (w) */
148 #define DMA2_MASK_REG 0xD4 /* single-channel mask (w) */
149 #define DMA2_MODE_REG 0xD6 /* mode register (w) */
150 #define DMA2_CLEAR_FF_REG 0xD8 /* clear pointer flip-flop (w) */
151 #define DMA2_TEMP_REG 0xDA /* Temporary Register (r) */
152 #define DMA2_RESET_REG 0xDA /* Master Clear (w) */
153 #define DMA2_CLR_MASK_REG 0xDC /* Clear Mask */
154 #define DMA2_MASK_ALL_REG 0xDE /* all-channels mask (w) */
155 #define DMA2_EXT_MODE_REG (0x400 | DMA2_MODE_REG)
156
157 #define DMA_ADDR_0 0x00 /* DMA address registers */
158 #define DMA_ADDR_1 0x02
159 #define DMA_ADDR_2 0x04
160 #define DMA_ADDR_3 0x06
161 #define DMA_ADDR_4 0xC0
162 #define DMA_ADDR_5 0xC4
163 #define DMA_ADDR_6 0xC8
164 #define DMA_ADDR_7 0xCC
165
166 #define DMA_CNT_0 0x01 /* DMA count registers */
167 #define DMA_CNT_1 0x03
168 #define DMA_CNT_2 0x05
169 #define DMA_CNT_3 0x07
170 #define DMA_CNT_4 0xC2
171 #define DMA_CNT_5 0xC6
172 #define DMA_CNT_6 0xCA
173 #define DMA_CNT_7 0xCE
174
175 #define DMA_PAGE_0 0x87 /* DMA page registers */
176 #define DMA_PAGE_1 0x83
177 #define DMA_PAGE_2 0x81
178 #define DMA_PAGE_3 0x82
179 #define DMA_PAGE_5 0x8B
180 #define DMA_PAGE_6 0x89
181 #define DMA_PAGE_7 0x8A
182
183 #define DMA_HIPAGE_0 (0x400 | DMA_PAGE_0)
184 #define DMA_HIPAGE_1 (0x400 | DMA_PAGE_1)
185 #define DMA_HIPAGE_2 (0x400 | DMA_PAGE_2)
186 #define DMA_HIPAGE_3 (0x400 | DMA_PAGE_3)
187 #define DMA_HIPAGE_4 (0x400 | DMA_PAGE_4)
188 #define DMA_HIPAGE_5 (0x400 | DMA_PAGE_5)
189 #define DMA_HIPAGE_6 (0x400 | DMA_PAGE_6)
190 #define DMA_HIPAGE_7 (0x400 | DMA_PAGE_7)
191
192 #define DMA_MODE_READ 0x44 /* I/O to memory, no autoinit, increment, single mode */
193 #define DMA_MODE_WRITE 0x48 /* memory to I/O, no autoinit, increment, single mode */
194 #define DMA_MODE_CASCADE 0xC0 /* pass thru DREQ->HRQ, DACK<-HLDA only */
195
196 #define DMA_AUTOINIT 0x10
197
198 extern spinlock_t dma_spin_lock;
199
claim_dma_lock(void)200 static __inline__ unsigned long claim_dma_lock(void)
201 {
202 unsigned long flags;
203 spin_lock_irqsave(&dma_spin_lock, flags);
204 return flags;
205 }
206
release_dma_lock(unsigned long flags)207 static __inline__ void release_dma_lock(unsigned long flags)
208 {
209 spin_unlock_irqrestore(&dma_spin_lock, flags);
210 }
211
212 /* enable/disable a specific DMA channel */
enable_dma(unsigned int dmanr)213 static __inline__ void enable_dma(unsigned int dmanr)
214 {
215 if (dmanr<=3)
216 dma_outb(dmanr, DMA1_MASK_REG);
217 else
218 dma_outb(dmanr & 3, DMA2_MASK_REG);
219 }
220
disable_dma(unsigned int dmanr)221 static __inline__ void disable_dma(unsigned int dmanr)
222 {
223 if (dmanr<=3)
224 dma_outb(dmanr | 4, DMA1_MASK_REG);
225 else
226 dma_outb((dmanr & 3) | 4, DMA2_MASK_REG);
227 }
228
229 /* Clear the 'DMA Pointer Flip Flop'.
230 * Write 0 for LSB/MSB, 1 for MSB/LSB access.
231 * Use this once to initialize the FF to a known state.
232 * After that, keep track of it. :-)
233 * --- In order to do that, the DMA routines below should ---
234 * --- only be used while interrupts are disabled! ---
235 */
clear_dma_ff(unsigned int dmanr)236 static __inline__ void clear_dma_ff(unsigned int dmanr)
237 {
238 if (dmanr<=3)
239 dma_outb(0, DMA1_CLEAR_FF_REG);
240 else
241 dma_outb(0, DMA2_CLEAR_FF_REG);
242 }
243
244 /* set mode (above) for a specific DMA channel */
set_dma_mode(unsigned int dmanr,char mode)245 static __inline__ void set_dma_mode(unsigned int dmanr, char mode)
246 {
247 if (dmanr<=3)
248 dma_outb(mode | dmanr, DMA1_MODE_REG);
249 else
250 dma_outb(mode | (dmanr&3), DMA2_MODE_REG);
251 }
252
253 /* set extended mode for a specific DMA channel */
set_dma_ext_mode(unsigned int dmanr,char ext_mode)254 static __inline__ void set_dma_ext_mode(unsigned int dmanr, char ext_mode)
255 {
256 if (dmanr<=3)
257 dma_outb(ext_mode | dmanr, DMA1_EXT_MODE_REG);
258 else
259 dma_outb(ext_mode | (dmanr&3), DMA2_EXT_MODE_REG);
260 }
261
262 /* Set only the page register bits of the transfer address.
263 * This is used for successive transfers when we know the contents of
264 * the lower 16 bits of the DMA current address register.
265 */
set_dma_page(unsigned int dmanr,unsigned int pagenr)266 static __inline__ void set_dma_page(unsigned int dmanr, unsigned int pagenr)
267 {
268 switch(dmanr) {
269 case 0:
270 dma_outb(pagenr, DMA_PAGE_0);
271 dma_outb((pagenr >> 8), DMA_HIPAGE_0);
272 break;
273 case 1:
274 dma_outb(pagenr, DMA_PAGE_1);
275 dma_outb((pagenr >> 8), DMA_HIPAGE_1);
276 break;
277 case 2:
278 dma_outb(pagenr, DMA_PAGE_2);
279 dma_outb((pagenr >> 8), DMA_HIPAGE_2);
280 break;
281 case 3:
282 dma_outb(pagenr, DMA_PAGE_3);
283 dma_outb((pagenr >> 8), DMA_HIPAGE_3);
284 break;
285 case 5:
286 dma_outb(pagenr & 0xfe, DMA_PAGE_5);
287 dma_outb((pagenr >> 8), DMA_HIPAGE_5);
288 break;
289 case 6:
290 dma_outb(pagenr & 0xfe, DMA_PAGE_6);
291 dma_outb((pagenr >> 8), DMA_HIPAGE_6);
292 break;
293 case 7:
294 dma_outb(pagenr & 0xfe, DMA_PAGE_7);
295 dma_outb((pagenr >> 8), DMA_HIPAGE_7);
296 break;
297 }
298 }
299
300
301 /* Set transfer address & page bits for specific DMA channel.
302 * Assumes dma flipflop is clear.
303 */
set_dma_addr(unsigned int dmanr,unsigned int a)304 static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a)
305 {
306 if (dmanr <= 3) {
307 dma_outb( a & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
308 dma_outb( (a>>8) & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
309 } else {
310 dma_outb( (a>>1) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
311 dma_outb( (a>>9) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
312 }
313 set_dma_page(dmanr, a>>16); /* set hipage last to enable 32-bit mode */
314 }
315
316
317 /* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for
318 * a specific DMA channel.
319 * You must ensure the parameters are valid.
320 * NOTE: from a manual: "the number of transfers is one more
321 * than the initial word count"! This is taken into account.
322 * Assumes dma flip-flop is clear.
323 * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7.
324 */
set_dma_count(unsigned int dmanr,unsigned int count)325 static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count)
326 {
327 count--;
328 if (dmanr <= 3) {
329 dma_outb( count & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
330 dma_outb( (count>>8) & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
331 } else {
332 dma_outb( (count>>1) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
333 dma_outb( (count>>9) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
334 }
335 }
336
337
338 /* Get DMA residue count. After a DMA transfer, this
339 * should return zero. Reading this while a DMA transfer is
340 * still in progress will return unpredictable results.
341 * If called before the channel has been used, it may return 1.
342 * Otherwise, it returns the number of _bytes_ left to transfer.
343 *
344 * Assumes DMA flip-flop is clear.
345 */
get_dma_residue(unsigned int dmanr)346 static __inline__ int get_dma_residue(unsigned int dmanr)
347 {
348 unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE
349 : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE;
350
351 /* using short to get 16-bit wrap around */
352 unsigned short count;
353
354 count = 1 + dma_inb(io_port);
355 count += dma_inb(io_port) << 8;
356
357 return (dmanr<=3)? count : (count<<1);
358 }
359
360
361 /* These are in kernel/dma.c: */
362 extern int request_dma(unsigned int dmanr, const char * device_id); /* reserve a DMA channel */
363 extern void free_dma(unsigned int dmanr); /* release it again */
364 #define KERNEL_HAVE_CHECK_DMA
365 extern int check_dma(unsigned int dmanr);
366
367 /* From PCI */
368
369 #ifdef CONFIG_PCI
370 extern int isa_dma_bridge_buggy;
371 #else
372 #define isa_dma_bridge_buggy (0)
373 #endif
374
375
376 #endif /* _ASM_DMA_H */
377