1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * include/asm-alpha/dma.h
4 *
5 * This is essentially the same as the i386 DMA stuff, as the AlphaPCs
6 * use ISA-compatible dma. The only extension is support for high-page
7 * registers that allow to set the top 8 bits of a 32-bit DMA address.
8 * This register should be written last when setting up a DMA address
9 * as this will also enable DMA across 64 KB boundaries.
10 */
11
12 /* $Id: dma.h,v 1.7 1992/12/14 00:29:34 root Exp root $
13 * linux/include/asm/dma.h: Defines for using and allocating dma channels.
14 * Written by Hennus Bergman, 1992.
15 * High DMA channel support & info by Hannu Savolainen
16 * and John Boyd, Nov. 1992.
17 */
18
19 #ifndef _ASM_DMA_H
20 #define _ASM_DMA_H
21
22 #include <linux/spinlock.h>
23 #include <asm/io.h>
24
25 #define dma_outb outb
26 #define dma_inb inb
27
28 /*
29 * NOTES about DMA transfers:
30 *
31 * controller 1: channels 0-3, byte operations, ports 00-1F
32 * controller 2: channels 4-7, word operations, ports C0-DF
33 *
34 * - ALL registers are 8 bits only, regardless of transfer size
35 * - channel 4 is not used - cascades 1 into 2.
36 * - channels 0-3 are byte - addresses/counts are for physical bytes
37 * - channels 5-7 are word - addresses/counts are for physical words
38 * - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries
39 * - transfer count loaded to registers is 1 less than actual count
40 * - controller 2 offsets are all even (2x offsets for controller 1)
41 * - page registers for 5-7 don't use data bit 0, represent 128K pages
42 * - page registers for 0-3 use bit 0, represent 64K pages
43 *
44 * DMA transfers are limited to the lower 16MB of _physical_ memory.
45 * Note that addresses loaded into registers must be _physical_ addresses,
46 * not logical addresses (which may differ if paging is active).
47 *
48 * Address mapping for channels 0-3:
49 *
50 * A23 ... A16 A15 ... A8 A7 ... A0 (Physical addresses)
51 * | ... | | ... | | ... |
52 * | ... | | ... | | ... |
53 * | ... | | ... | | ... |
54 * P7 ... P0 A7 ... A0 A7 ... A0
55 * | Page | Addr MSB | Addr LSB | (DMA registers)
56 *
57 * Address mapping for channels 5-7:
58 *
59 * A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0 (Physical addresses)
60 * | ... | \ \ ... \ \ \ ... \ \
61 * | ... | \ \ ... \ \ \ ... \ (not used)
62 * | ... | \ \ ... \ \ \ ... \
63 * P7 ... P1 (0) A7 A6 ... A0 A7 A6 ... A0
64 * | Page | Addr MSB | Addr LSB | (DMA registers)
65 *
66 * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses
67 * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at
68 * the hardware level, so odd-byte transfers aren't possible).
69 *
70 * Transfer count (_not # bytes_) is limited to 64K, represented as actual
71 * count - 1 : 64K => 0xFFFF, 1 => 0x0000. Thus, count is always 1 or more,
72 * and up to 128K bytes may be transferred on channels 5-7 in one operation.
73 *
74 */
75
76 #define MAX_DMA_CHANNELS 8
77
78 /*
79 ISA DMA limitations on Alpha platforms,
80
81 These may be due to SIO (PCI<->ISA bridge) chipset limitation, or
82 just a wiring limit.
83 */
84
85 /* The maximum address for ISA DMA transfer on RUFFIAN,
86 due to an hardware SIO limitation, is 16MB.
87 */
88 #define ALPHA_RUFFIAN_MAX_ISA_DMA_ADDRESS 0x01000000UL
89
90 /* The maximum address for ISA DMA transfer on SABLE, and some ALCORs,
91 due to an hardware SIO chip limitation, is 2GB.
92 */
93 #define ALPHA_SABLE_MAX_ISA_DMA_ADDRESS 0x80000000UL
94 #define ALPHA_ALCOR_MAX_ISA_DMA_ADDRESS 0x80000000UL
95
96 /*
97 Maximum address for all the others is the complete 32-bit bus
98 address space.
99 */
100 #define ALPHA_MAX_ISA_DMA_ADDRESS 0x100000000UL
101
102 #ifdef CONFIG_ALPHA_GENERIC
103 # define MAX_ISA_DMA_ADDRESS (alpha_mv.max_isa_dma_address)
104 #else
105 # if defined(CONFIG_ALPHA_RUFFIAN)
106 # define MAX_ISA_DMA_ADDRESS ALPHA_RUFFIAN_MAX_ISA_DMA_ADDRESS
107 # elif defined(CONFIG_ALPHA_SABLE)
108 # define MAX_ISA_DMA_ADDRESS ALPHA_SABLE_MAX_ISA_DMA_ADDRESS
109 # elif defined(CONFIG_ALPHA_ALCOR)
110 # define MAX_ISA_DMA_ADDRESS ALPHA_ALCOR_MAX_ISA_DMA_ADDRESS
111 # else
112 # define MAX_ISA_DMA_ADDRESS ALPHA_MAX_ISA_DMA_ADDRESS
113 # endif
114 #endif
115
116 /* If we have the iommu, we don't have any address limitations on DMA.
117 Otherwise (Nautilus, RX164), we have to have 0-16 Mb DMA zone
118 like i386. */
119 #define MAX_DMA_ADDRESS (alpha_mv.mv_pci_tbi ? \
120 ~0UL : IDENT_ADDR + 0x01000000)
121
122 /* 8237 DMA controllers */
123 #define IO_DMA1_BASE 0x00 /* 8 bit slave DMA, channels 0..3 */
124 #define IO_DMA2_BASE 0xC0 /* 16 bit master DMA, ch 4(=slave input)..7 */
125
126 /* DMA controller registers */
127 #define DMA1_CMD_REG 0x08 /* command register (w) */
128 #define DMA1_STAT_REG 0x08 /* status register (r) */
129 #define DMA1_REQ_REG 0x09 /* request register (w) */
130 #define DMA1_MASK_REG 0x0A /* single-channel mask (w) */
131 #define DMA1_MODE_REG 0x0B /* mode register (w) */
132 #define DMA1_CLEAR_FF_REG 0x0C /* clear pointer flip-flop (w) */
133 #define DMA1_TEMP_REG 0x0D /* Temporary Register (r) */
134 #define DMA1_RESET_REG 0x0D /* Master Clear (w) */
135 #define DMA1_CLR_MASK_REG 0x0E /* Clear Mask */
136 #define DMA1_MASK_ALL_REG 0x0F /* all-channels mask (w) */
137 #define DMA1_EXT_MODE_REG (0x400 | DMA1_MODE_REG)
138
139 #define DMA2_CMD_REG 0xD0 /* command register (w) */
140 #define DMA2_STAT_REG 0xD0 /* status register (r) */
141 #define DMA2_REQ_REG 0xD2 /* request register (w) */
142 #define DMA2_MASK_REG 0xD4 /* single-channel mask (w) */
143 #define DMA2_MODE_REG 0xD6 /* mode register (w) */
144 #define DMA2_CLEAR_FF_REG 0xD8 /* clear pointer flip-flop (w) */
145 #define DMA2_TEMP_REG 0xDA /* Temporary Register (r) */
146 #define DMA2_RESET_REG 0xDA /* Master Clear (w) */
147 #define DMA2_CLR_MASK_REG 0xDC /* Clear Mask */
148 #define DMA2_MASK_ALL_REG 0xDE /* all-channels mask (w) */
149 #define DMA2_EXT_MODE_REG (0x400 | DMA2_MODE_REG)
150
151 #define DMA_ADDR_0 0x00 /* DMA address registers */
152 #define DMA_ADDR_1 0x02
153 #define DMA_ADDR_2 0x04
154 #define DMA_ADDR_3 0x06
155 #define DMA_ADDR_4 0xC0
156 #define DMA_ADDR_5 0xC4
157 #define DMA_ADDR_6 0xC8
158 #define DMA_ADDR_7 0xCC
159
160 #define DMA_CNT_0 0x01 /* DMA count registers */
161 #define DMA_CNT_1 0x03
162 #define DMA_CNT_2 0x05
163 #define DMA_CNT_3 0x07
164 #define DMA_CNT_4 0xC2
165 #define DMA_CNT_5 0xC6
166 #define DMA_CNT_6 0xCA
167 #define DMA_CNT_7 0xCE
168
169 #define DMA_PAGE_0 0x87 /* DMA page registers */
170 #define DMA_PAGE_1 0x83
171 #define DMA_PAGE_2 0x81
172 #define DMA_PAGE_3 0x82
173 #define DMA_PAGE_5 0x8B
174 #define DMA_PAGE_6 0x89
175 #define DMA_PAGE_7 0x8A
176
177 #define DMA_HIPAGE_0 (0x400 | DMA_PAGE_0)
178 #define DMA_HIPAGE_1 (0x400 | DMA_PAGE_1)
179 #define DMA_HIPAGE_2 (0x400 | DMA_PAGE_2)
180 #define DMA_HIPAGE_3 (0x400 | DMA_PAGE_3)
181 #define DMA_HIPAGE_4 (0x400 | DMA_PAGE_4)
182 #define DMA_HIPAGE_5 (0x400 | DMA_PAGE_5)
183 #define DMA_HIPAGE_6 (0x400 | DMA_PAGE_6)
184 #define DMA_HIPAGE_7 (0x400 | DMA_PAGE_7)
185
186 #define DMA_MODE_READ 0x44 /* I/O to memory, no autoinit, increment, single mode */
187 #define DMA_MODE_WRITE 0x48 /* memory to I/O, no autoinit, increment, single mode */
188 #define DMA_MODE_CASCADE 0xC0 /* pass thru DREQ->HRQ, DACK<-HLDA only */
189
190 #define DMA_AUTOINIT 0x10
191
192 extern spinlock_t dma_spin_lock;
193
194 static __inline__ unsigned long claim_dma_lock(void)
195 {
196 unsigned long flags;
197 spin_lock_irqsave(&dma_spin_lock, flags);
198 return flags;
199 }
200
201 static __inline__ void release_dma_lock(unsigned long flags)
202 {
203 spin_unlock_irqrestore(&dma_spin_lock, flags);
204 }
205
206 /* enable/disable a specific DMA channel */
207 static __inline__ void enable_dma(unsigned int dmanr)
208 {
209 if (dmanr<=3)
210 dma_outb(dmanr, DMA1_MASK_REG);
211 else
212 dma_outb(dmanr & 3, DMA2_MASK_REG);
213 }
214
215 static __inline__ void disable_dma(unsigned int dmanr)
216 {
217 if (dmanr<=3)
218 dma_outb(dmanr | 4, DMA1_MASK_REG);
219 else
220 dma_outb((dmanr & 3) | 4, DMA2_MASK_REG);
221 }
222
223 /* Clear the 'DMA Pointer Flip Flop'.
224 * Write 0 for LSB/MSB, 1 for MSB/LSB access.
225 * Use this once to initialize the FF to a known state.
226 * After that, keep track of it. :-)
227 * --- In order to do that, the DMA routines below should ---
228 * --- only be used while interrupts are disabled! ---
229 */
230 static __inline__ void clear_dma_ff(unsigned int dmanr)
231 {
232 if (dmanr<=3)
233 dma_outb(0, DMA1_CLEAR_FF_REG);
234 else
235 dma_outb(0, DMA2_CLEAR_FF_REG);
236 }
237
238 /* set mode (above) for a specific DMA channel */
239 static __inline__ void set_dma_mode(unsigned int dmanr, char mode)
240 {
241 if (dmanr<=3)
242 dma_outb(mode | dmanr, DMA1_MODE_REG);
243 else
244 dma_outb(mode | (dmanr&3), DMA2_MODE_REG);
245 }
246
247 /* set extended mode for a specific DMA channel */
248 static __inline__ void set_dma_ext_mode(unsigned int dmanr, char ext_mode)
249 {
250 if (dmanr<=3)
251 dma_outb(ext_mode | dmanr, DMA1_EXT_MODE_REG);
252 else
253 dma_outb(ext_mode | (dmanr&3), DMA2_EXT_MODE_REG);
254 }
255
256 /* Set only the page register bits of the transfer address.
257 * This is used for successive transfers when we know the contents of
258 * the lower 16 bits of the DMA current address register.
259 */
260 static __inline__ void set_dma_page(unsigned int dmanr, unsigned int pagenr)
261 {
262 switch(dmanr) {
263 case 0:
264 dma_outb(pagenr, DMA_PAGE_0);
265 dma_outb((pagenr >> 8), DMA_HIPAGE_0);
266 break;
267 case 1:
268 dma_outb(pagenr, DMA_PAGE_1);
269 dma_outb((pagenr >> 8), DMA_HIPAGE_1);
270 break;
271 case 2:
272 dma_outb(pagenr, DMA_PAGE_2);
273 dma_outb((pagenr >> 8), DMA_HIPAGE_2);
274 break;
275 case 3:
276 dma_outb(pagenr, DMA_PAGE_3);
277 dma_outb((pagenr >> 8), DMA_HIPAGE_3);
278 break;
279 case 5:
280 dma_outb(pagenr & 0xfe, DMA_PAGE_5);
281 dma_outb((pagenr >> 8), DMA_HIPAGE_5);
282 break;
283 case 6:
284 dma_outb(pagenr & 0xfe, DMA_PAGE_6);
285 dma_outb((pagenr >> 8), DMA_HIPAGE_6);
286 break;
287 case 7:
288 dma_outb(pagenr & 0xfe, DMA_PAGE_7);
289 dma_outb((pagenr >> 8), DMA_HIPAGE_7);
290 break;
291 }
292 }
293
294
295 /* Set transfer address & page bits for specific DMA channel.
296 * Assumes dma flipflop is clear.
297 */
298 static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a)
299 {
300 if (dmanr <= 3) {
301 dma_outb( a & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
302 dma_outb( (a>>8) & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
303 } else {
304 dma_outb( (a>>1) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
305 dma_outb( (a>>9) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
306 }
307 set_dma_page(dmanr, a>>16); /* set hipage last to enable 32-bit mode */
308 }
309
310
311 /* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for
312 * a specific DMA channel.
313 * You must ensure the parameters are valid.
314 * NOTE: from a manual: "the number of transfers is one more
315 * than the initial word count"! This is taken into account.
316 * Assumes dma flip-flop is clear.
317 * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7.
318 */
319 static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count)
320 {
321 count--;
322 if (dmanr <= 3) {
323 dma_outb( count & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
324 dma_outb( (count>>8) & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
325 } else {
326 dma_outb( (count>>1) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
327 dma_outb( (count>>9) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
328 }
329 }
330
331
332 /* Get DMA residue count. After a DMA transfer, this
333 * should return zero. Reading this while a DMA transfer is
334 * still in progress will return unpredictable results.
335 * If called before the channel has been used, it may return 1.
336 * Otherwise, it returns the number of _bytes_ left to transfer.
337 *
338 * Assumes DMA flip-flop is clear.
339 */
340 static __inline__ int get_dma_residue(unsigned int dmanr)
341 {
342 unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE
343 : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE;
344
345 /* using short to get 16-bit wrap around */
346 unsigned short count;
347
348 count = 1 + dma_inb(io_port);
349 count += dma_inb(io_port) << 8;
350
351 return (dmanr<=3)? count : (count<<1);
352 }
353
354
355 /* These are in kernel/dma.c: */
356 extern int request_dma(unsigned int dmanr, const char * device_id); /* reserve a DMA channel */
357 extern void free_dma(unsigned int dmanr); /* release it again */
358 #define KERNEL_HAVE_CHECK_DMA
359 extern int check_dma(unsigned int dmanr);
360
361 #endif /* _ASM_DMA_H */
362
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