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drm/amd/display: Update MST edid property every time
[linux/fpc-iii.git] / drivers / macintosh / via-macii.c
blob4ba06a1695ea16fc2e02987f23213578f68dc890
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Device driver for the via ADB on (many) Mac II-class machines
4 *
5 * Based on the original ADB keyboard handler Copyright (c) 1997 Alan Cox
6 * Also derived from code Copyright (C) 1996 Paul Mackerras.
7 *
8 * With various updates provided over the years by Michael Schmitz,
9 * Guideo Koerber and others.
10 *
11 * Rewrite for Unified ADB by Joshua M. Thompson (funaho@jurai.org)
12 *
13 * 1999-08-02 (jmt) - Initial rewrite for Unified ADB.
14 * 2000-03-29 Tony Mantler <tonym@mac.linux-m68k.org>
15 * - Big overhaul, should actually work now.
16 * 2006-12-31 Finn Thain - Another overhaul.
17 *
18 * Suggested reading:
19 * Inside Macintosh, ch. 5 ADB Manager
20 * Guide to the Macinstosh Family Hardware, ch. 8 Apple Desktop Bus
21 * Rockwell R6522 VIA datasheet
22 *
23 * Apple's "ADB Analyzer" bus sniffer is invaluable:
24 * ftp://ftp.apple.com/developer/Tool_Chest/Devices_-_Hardware/Apple_Desktop_Bus/
25 */
26
27 #include <stdarg.h>
28 #include <linux/types.h>
29 #include <linux/errno.h>
30 #include <linux/kernel.h>
31 #include <linux/delay.h>
32 #include <linux/adb.h>
33 #include <linux/interrupt.h>
34 #include <linux/init.h>
35 #include <asm/macintosh.h>
36 #include <asm/macints.h>
37 #include <asm/mac_via.h>
38
39 static volatile unsigned char *via;
40
41 /* VIA registers - spaced 0x200 bytes apart */
42 #define RS 0x200 /* skip between registers */
43 #define B 0 /* B-side data */
44 #define A RS /* A-side data */
45 #define DIRB (2*RS) /* B-side direction (1=output) */
46 #define DIRA (3*RS) /* A-side direction (1=output) */
47 #define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */
48 #define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */
49 #define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */
50 #define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */
51 #define T2CL (8*RS) /* Timer 2 ctr/latch (low 8 bits) */
52 #define T2CH (9*RS) /* Timer 2 counter (high 8 bits) */
53 #define SR (10*RS) /* Shift register */
54 #define ACR (11*RS) /* Auxiliary control register */
55 #define PCR (12*RS) /* Peripheral control register */
56 #define IFR (13*RS) /* Interrupt flag register */
57 #define IER (14*RS) /* Interrupt enable register */
58 #define ANH (15*RS) /* A-side data, no handshake */
59
60 /* Bits in B data register: all active low */
61 #define CTLR_IRQ 0x08 /* Controller rcv status (input) */
62 #define ST_MASK 0x30 /* mask for selecting ADB state bits */
63
64 /* Bits in ACR */
65 #define SR_CTRL 0x1c /* Shift register control bits */
66 #define SR_EXT 0x0c /* Shift on external clock */
67 #define SR_OUT 0x10 /* Shift out if 1 */
68
69 /* Bits in IFR and IER */
70 #define IER_SET 0x80 /* set bits in IER */
71 #define IER_CLR 0 /* clear bits in IER */
72 #define SR_INT 0x04 /* Shift register full/empty */
73
74 /* ADB transaction states according to GMHW */
75 #define ST_CMD 0x00 /* ADB state: command byte */
76 #define ST_EVEN 0x10 /* ADB state: even data byte */
77 #define ST_ODD 0x20 /* ADB state: odd data byte */
78 #define ST_IDLE 0x30 /* ADB state: idle, nothing to send */
79
80 static int macii_init_via(void);
81 static void macii_start(void);
82 static irqreturn_t macii_interrupt(int irq, void *arg);
83 static void macii_queue_poll(void);
84
85 static int macii_probe(void);
86 static int macii_init(void);
87 static int macii_send_request(struct adb_request *req, int sync);
88 static int macii_write(struct adb_request *req);
89 static int macii_autopoll(int devs);
90 static void macii_poll(void);
91 static int macii_reset_bus(void);
92
93 struct adb_driver via_macii_driver = {
94 "Mac II",
95 macii_probe,
96 macii_init,
97 macii_send_request,
98 macii_autopoll,
99 macii_poll,
100 macii_reset_bus
101 };
102
103 static enum macii_state {
104 idle,
105 sending,
106 reading,
107 read_done,
108 } macii_state;
109
110 static struct adb_request *current_req; /* first request struct in the queue */
111 static struct adb_request *last_req; /* last request struct in the queue */
112 static unsigned char reply_buf[16]; /* storage for autopolled replies */
113 static unsigned char *reply_ptr; /* next byte in reply_buf or req->reply */
114 static int reading_reply; /* store reply in reply_buf else req->reply */
115 static int data_index; /* index of the next byte to send from req->data */
116 static int reply_len; /* number of bytes received in reply_buf or req->reply */
117 static int status; /* VIA's ADB status bits captured upon interrupt */
118 static int last_status; /* status bits as at previous interrupt */
119 static int srq_asserted; /* have to poll for the device that asserted it */
120 static int command_byte; /* the most recent command byte transmitted */
121 static int autopoll_devs; /* bits set are device addresses to be polled */
122
123 /* Sanity check for request queue. Doesn't check for cycles. */
124 static int request_is_queued(struct adb_request *req) {
125 struct adb_request *cur;
126 unsigned long flags;
127 local_irq_save(flags);
128 cur = current_req;
129 while (cur) {
130 if (cur == req) {
131 local_irq_restore(flags);
132 return 1;
133 }
134 cur = cur->next;
135 }
136 local_irq_restore(flags);
137 return 0;
138 }
139
140 /* Check for MacII style ADB */
141 static int macii_probe(void)
142 {
143 if (macintosh_config->adb_type != MAC_ADB_II) return -ENODEV;
144
145 via = via1;
146
147 printk("adb: Mac II ADB Driver v1.0 for Unified ADB\n");
148 return 0;
149 }
150
151 /* Initialize the driver */
152 int macii_init(void)
153 {
154 unsigned long flags;
155 int err;
156
157 local_irq_save(flags);
158
159 err = macii_init_via();
160 if (err) goto out;
161
162 err = request_irq(IRQ_MAC_ADB, macii_interrupt, 0, "ADB",
163 macii_interrupt);
164 if (err) goto out;
165
166 macii_state = idle;
167 out:
168 local_irq_restore(flags);
169 return err;
170 }
171
172 /* initialize the hardware */
173 static int macii_init_via(void)
174 {
175 unsigned char x;
176
177 /* We want CTLR_IRQ as input and ST_EVEN | ST_ODD as output lines. */
178 via[DIRB] = (via[DIRB] | ST_EVEN | ST_ODD) & ~CTLR_IRQ;
179
180 /* Set up state: idle */
181 via[B] |= ST_IDLE;
182 last_status = via[B] & (ST_MASK|CTLR_IRQ);
183
184 /* Shift register on input */
185 via[ACR] = (via[ACR] & ~SR_CTRL) | SR_EXT;
186
187 /* Wipe any pending data and int */
188 x = via[SR];
189
190 return 0;
191 }
192
193 /* Send an ADB poll (Talk Register 0 command prepended to the request queue) */
194 static void macii_queue_poll(void)
195 {
196 /* No point polling the active device as it will never assert SRQ, so
197 * poll the next device in the autopoll list. This could leave us
198 * stuck in a polling loop if an unprobed device is asserting SRQ.
199 * In theory, that could only happen if a device was plugged in after
200 * probing started. Unplugging it again will break the cycle.
201 * (Simply polling the next higher device often ends up polling almost
202 * every device (after wrapping around), which takes too long.)
203 */
204 int device_mask;
205 int next_device;
206 static struct adb_request req;
207
208 if (!autopoll_devs) return;
209
210 device_mask = (1 << (((command_byte & 0xF0) >> 4) + 1)) - 1;
211 if (autopoll_devs & ~device_mask)
212 next_device = ffs(autopoll_devs & ~device_mask) - 1;
213 else
214 next_device = ffs(autopoll_devs) - 1;
215
216 BUG_ON(request_is_queued(&req));
217
218 adb_request(&req, NULL, ADBREQ_NOSEND, 1,
219 ADB_READREG(next_device, 0));
220
221 req.sent = 0;
222 req.complete = 0;
223 req.reply_len = 0;
224 req.next = current_req;
225
226 if (current_req != NULL) {
227 current_req = &req;
228 } else {
229 current_req = &req;
230 last_req = &req;
231 }
232 }
233
234 /* Send an ADB request; if sync, poll out the reply 'till it's done */
235 static int macii_send_request(struct adb_request *req, int sync)
236 {
237 int err;
238 unsigned long flags;
239
240 BUG_ON(request_is_queued(req));
241
242 local_irq_save(flags);
243 err = macii_write(req);
244 local_irq_restore(flags);
245
246 if (!err && sync) {
247 while (!req->complete) {
248 macii_poll();
249 }
250 BUG_ON(request_is_queued(req));
251 }
252
253 return err;
254 }
255
256 /* Send an ADB request (append to request queue) */
257 static int macii_write(struct adb_request *req)
258 {
259 if (req->nbytes < 2 || req->data[0] != ADB_PACKET || req->nbytes > 15) {
260 req->complete = 1;
261 return -EINVAL;
262 }
263
264 req->next = NULL;
265 req->sent = 0;
266 req->complete = 0;
267 req->reply_len = 0;
268
269 if (current_req != NULL) {
270 last_req->next = req;
271 last_req = req;
272 } else {
273 current_req = req;
274 last_req = req;
275 if (macii_state == idle) macii_start();
276 }
277 return 0;
278 }
279
280 /* Start auto-polling */
281 static int macii_autopoll(int devs)
282 {
283 static struct adb_request req;
284 unsigned long flags;
285 int err = 0;
286
287 /* bit 1 == device 1, and so on. */
288 autopoll_devs = devs & 0xFFFE;
289
290 if (!autopoll_devs) return 0;
291
292 local_irq_save(flags);
293
294 if (current_req == NULL) {
295 /* Send a Talk Reg 0. The controller will repeatedly transmit
296 * this as long as it is idle.
297 */
298 adb_request(&req, NULL, ADBREQ_NOSEND, 1,
299 ADB_READREG(ffs(autopoll_devs) - 1, 0));
300 err = macii_write(&req);
301 }
302
303 local_irq_restore(flags);
304 return err;
305 }
306
307 static inline int need_autopoll(void) {
308 /* Was the last command Talk Reg 0
309 * and is the target on the autopoll list?
310 */
311 if ((command_byte & 0x0F) == 0x0C &&
312 ((1 << ((command_byte & 0xF0) >> 4)) & autopoll_devs))
313 return 0;
314 return 1;
315 }
316
317 /* Prod the chip without interrupts */
318 static void macii_poll(void)
319 {
320 disable_irq(IRQ_MAC_ADB);
321 macii_interrupt(0, NULL);
322 enable_irq(IRQ_MAC_ADB);
323 }
324
325 /* Reset the bus */
326 static int macii_reset_bus(void)
327 {
328 static struct adb_request req;
329
330 if (request_is_queued(&req))
331 return 0;
332
333 /* Command = 0, Address = ignored */
334 adb_request(&req, NULL, 0, 1, ADB_BUSRESET);
335
336 /* Don't want any more requests during the Global Reset low time. */
337 udelay(3000);
338
339 return 0;
340 }
341
342 /* Start sending ADB packet */
343 static void macii_start(void)
344 {
345 struct adb_request *req;
346
347 req = current_req;
348
349 BUG_ON(req == NULL);
350
351 BUG_ON(macii_state != idle);
352
353 /* Now send it. Be careful though, that first byte of the request
354 * is actually ADB_PACKET; the real data begins at index 1!
355 * And req->nbytes is the number of bytes of real data plus one.
356 */
357
358 /* store command byte */
359 command_byte = req->data[1];
360 /* Output mode */
361 via[ACR] |= SR_OUT;
362 /* Load data */
363 via[SR] = req->data[1];
364 /* set ADB state to 'command' */
365 via[B] = (via[B] & ~ST_MASK) | ST_CMD;
366
367 macii_state = sending;
368 data_index = 2;
369 }
370
371 /*
372 * The notorious ADB interrupt handler - does all of the protocol handling.
373 * Relies on the ADB controller sending and receiving data, thereby
374 * generating shift register interrupts (SR_INT) for us. This means there has
375 * to be activity on the ADB bus. The chip will poll to achieve this.
376 *
377 * The basic ADB state machine was left unchanged from the original MacII code
378 * by Alan Cox, which was based on the CUDA driver for PowerMac.
379 * The syntax of the ADB status lines is totally different on MacII,
380 * though. MacII uses the states Command -> Even -> Odd -> Even ->...-> Idle
381 * for sending and Idle -> Even -> Odd -> Even ->...-> Idle for receiving.
382 * Start and end of a receive packet are signalled by asserting /IRQ on the
383 * interrupt line (/IRQ means the CTLR_IRQ bit in port B; not to be confused
384 * with the VIA shift register interrupt. /IRQ never actually interrupts the
385 * processor, it's just an ordinary input.)
386 */
387 static irqreturn_t macii_interrupt(int irq, void *arg)
388 {
389 int x;
390 static int entered;
391 struct adb_request *req;
392
393 if (!arg) {
394 /* Clear the SR IRQ flag when polling. */
395 if (via[IFR] & SR_INT)
396 via[IFR] = SR_INT;
397 else
398 return IRQ_NONE;
399 }
400
401 BUG_ON(entered++);
402
403 last_status = status;
404 status = via[B] & (ST_MASK|CTLR_IRQ);
405
406 switch (macii_state) {
407 case idle:
408 if (reading_reply) {
409 reply_ptr = current_req->reply;
410 } else {
411 BUG_ON(current_req != NULL);
412 reply_ptr = reply_buf;
413 }
414
415 x = via[SR];
416
417 if ((status & CTLR_IRQ) && (x == 0xFF)) {
418 /* Bus timeout without SRQ sequence:
419 * data is "FF" while CTLR_IRQ is "H"
420 */
421 reply_len = 0;
422 srq_asserted = 0;
423 macii_state = read_done;
424 } else {
425 macii_state = reading;
426 *reply_ptr = x;
427 reply_len = 1;
428 }
429
430 /* set ADB state = even for first data byte */
431 via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
432 break;
433
434 case sending:
435 req = current_req;
436 if (data_index >= req->nbytes) {
437 req->sent = 1;
438 macii_state = idle;
439
440 if (req->reply_expected) {
441 reading_reply = 1;
442 } else {
443 req->complete = 1;
444 current_req = req->next;
445 if (req->done) (*req->done)(req);
446
447 if (current_req)
448 macii_start();
449 else
450 if (need_autopoll())
451 macii_autopoll(autopoll_devs);
452 }
453
454 if (macii_state == idle) {
455 /* reset to shift in */
456 via[ACR] &= ~SR_OUT;
457 x = via[SR];
458 /* set ADB state idle - might get SRQ */
459 via[B] = (via[B] & ~ST_MASK) | ST_IDLE;
460 }
461 } else {
462 via[SR] = req->data[data_index++];
463
464 if ( (via[B] & ST_MASK) == ST_CMD ) {
465 /* just sent the command byte, set to EVEN */
466 via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
467 } else {
468 /* invert state bits, toggle ODD/EVEN */
469 via[B] ^= ST_MASK;
470 }
471 }
472 break;
473
474 case reading:
475 x = via[SR];
476 BUG_ON((status & ST_MASK) == ST_CMD ||
477 (status & ST_MASK) == ST_IDLE);
478
479 /* Bus timeout with SRQ sequence:
480 * data is "XX FF" while CTLR_IRQ is "L L"
481 * End of packet without SRQ sequence:
482 * data is "XX...YY 00" while CTLR_IRQ is "L...H L"
483 * End of packet SRQ sequence:
484 * data is "XX...YY 00" while CTLR_IRQ is "L...L L"
485 * (where XX is the first response byte and
486 * YY is the last byte of valid response data.)
487 */
488
489 srq_asserted = 0;
490 if (!(status & CTLR_IRQ)) {
491 if (x == 0xFF) {
492 if (!(last_status & CTLR_IRQ)) {
493 macii_state = read_done;
494 reply_len = 0;
495 srq_asserted = 1;
496 }
497 } else if (x == 0x00) {
498 macii_state = read_done;
499 if (!(last_status & CTLR_IRQ))
500 srq_asserted = 1;
501 }
502 }
503
504 if (macii_state == reading) {
505 BUG_ON(reply_len > 15);
506 reply_ptr++;
507 *reply_ptr = x;
508 reply_len++;
509 }
510
511 /* invert state bits, toggle ODD/EVEN */
512 via[B] ^= ST_MASK;
513 break;
514
515 case read_done:
516 x = via[SR];
517
518 if (reading_reply) {
519 reading_reply = 0;
520 req = current_req;
521 req->reply_len = reply_len;
522 req->complete = 1;
523 current_req = req->next;
524 if (req->done) (*req->done)(req);
525 } else if (reply_len && autopoll_devs)
526 adb_input(reply_buf, reply_len, 0);
527
528 macii_state = idle;
529
530 /* SRQ seen before, initiate poll now */
531 if (srq_asserted)
532 macii_queue_poll();
533
534 if (current_req)
535 macii_start();
536 else
537 if (need_autopoll())
538 macii_autopoll(autopoll_devs);
539
540 if (macii_state == idle)
541 via[B] = (via[B] & ~ST_MASK) | ST_IDLE;
542 break;
543
544 default:
545 break;
546 }
547
548 entered--;
549 return IRQ_HANDLED;
550 }
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