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[PATCH] W1: possible cleanups
[linux-2.6/verdex.git] / drivers / macintosh / via-macii.c
blob2a2ffe060169a5f96d9679466b745f8341ee5397
1 /*
2 * Device driver for the via ADB on (many) Mac II-class machines
3 *
4 * Based on the original ADB keyboard handler Copyright (c) 1997 Alan Cox
5 * Also derived from code Copyright (C) 1996 Paul Mackerras.
6 *
7 * With various updates provided over the years by Michael Schmitz,
8 * Guideo Koerber and others.
9 *
10 * Rewrite for Unified ADB by Joshua M. Thompson (funaho@jurai.org)
11 *
12 * 1999-08-02 (jmt) - Initial rewrite for Unified ADB.
13 * 2000-03-29 Tony Mantler <tonym@mac.linux-m68k.org>
14 * - Big overhaul, should actually work now.
15 */
16
17 #include <stdarg.h>
18 #include <linux/types.h>
19 #include <linux/errno.h>
20 #include <linux/kernel.h>
21 #include <linux/delay.h>
22 #include <linux/sched.h>
23 #include <linux/adb.h>
24 #include <linux/interrupt.h>
25 #include <linux/init.h>
26 #include <asm/macintosh.h>
27 #include <asm/macints.h>
28 #include <asm/machw.h>
29 #include <asm/mac_via.h>
30 #include <asm/io.h>
31 #include <asm/system.h>
32
33 static volatile unsigned char *via;
34
35 /* VIA registers - spaced 0x200 bytes apart */
36 #define RS 0x200 /* skip between registers */
37 #define B 0 /* B-side data */
38 #define A RS /* A-side data */
39 #define DIRB (2*RS) /* B-side direction (1=output) */
40 #define DIRA (3*RS) /* A-side direction (1=output) */
41 #define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */
42 #define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */
43 #define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */
44 #define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */
45 #define T2CL (8*RS) /* Timer 2 ctr/latch (low 8 bits) */
46 #define T2CH (9*RS) /* Timer 2 counter (high 8 bits) */
47 #define SR (10*RS) /* Shift register */
48 #define ACR (11*RS) /* Auxiliary control register */
49 #define PCR (12*RS) /* Peripheral control register */
50 #define IFR (13*RS) /* Interrupt flag register */
51 #define IER (14*RS) /* Interrupt enable register */
52 #define ANH (15*RS) /* A-side data, no handshake */
53
54 /* Bits in B data register: all active low */
55 #define TREQ 0x08 /* Transfer request (input) */
56 #define TACK 0x10 /* Transfer acknowledge (output) */
57 #define TIP 0x20 /* Transfer in progress (output) */
58 #define ST_MASK 0x30 /* mask for selecting ADB state bits */
59
60 /* Bits in ACR */
61 #define SR_CTRL 0x1c /* Shift register control bits */
62 #define SR_EXT 0x0c /* Shift on external clock */
63 #define SR_OUT 0x10 /* Shift out if 1 */
64
65 /* Bits in IFR and IER */
66 #define IER_SET 0x80 /* set bits in IER */
67 #define IER_CLR 0 /* clear bits in IER */
68 #define SR_INT 0x04 /* Shift register full/empty */
69 #define SR_DATA 0x08 /* Shift register data */
70 #define SR_CLOCK 0x10 /* Shift register clock */
71
72 /* ADB transaction states according to GMHW */
73 #define ST_CMD 0x00 /* ADB state: command byte */
74 #define ST_EVEN 0x10 /* ADB state: even data byte */
75 #define ST_ODD 0x20 /* ADB state: odd data byte */
76 #define ST_IDLE 0x30 /* ADB state: idle, nothing to send */
77
78 static int macii_init_via(void);
79 static void macii_start(void);
80 static irqreturn_t macii_interrupt(int irq, void *arg, struct pt_regs *regs);
81 static void macii_retransmit(int);
82 static void macii_queue_poll(void);
83
84 static int macii_probe(void);
85 static int macii_init(void);
86 static int macii_send_request(struct adb_request *req, int sync);
87 static int macii_write(struct adb_request *req);
88 static int macii_autopoll(int devs);
89 static void macii_poll(void);
90 static int macii_reset_bus(void);
91
92 struct adb_driver via_macii_driver = {
93 "Mac II",
94 macii_probe,
95 macii_init,
96 macii_send_request,
97 macii_autopoll,
98 macii_poll,
99 macii_reset_bus
100 };
101
102 static enum macii_state {
103 idle,
104 sending,
105 reading,
106 read_done,
107 awaiting_reply
108 } macii_state;
109
110 static int need_poll = 0;
111 static int command_byte = 0;
112 static int last_reply = 0;
113 static int last_active = 0;
114
115 static struct adb_request *current_req;
116 static struct adb_request *last_req;
117 static struct adb_request *retry_req;
118 static unsigned char reply_buf[16];
119 static unsigned char *reply_ptr;
120 static int reply_len;
121 static int reading_reply;
122 static int data_index;
123 static int first_byte;
124 static int prefix_len;
125 static int status = ST_IDLE|TREQ;
126 static int last_status;
127 static int driver_running = 0;
128
129 /* debug level 10 required for ADB logging (should be && debug_adb, ideally) */
130
131 /* Check for MacII style ADB */
132 static int macii_probe(void)
133 {
134 if (macintosh_config->adb_type != MAC_ADB_II) return -ENODEV;
135
136 via = via1;
137
138 printk("adb: Mac II ADB Driver v1.0 for Unified ADB\n");
139 return 0;
140 }
141
142 /* Initialize the driver */
143 int macii_init(void)
144 {
145 unsigned long flags;
146 int err;
147
148 local_irq_save(flags);
149
150 err = macii_init_via();
151 if (err) return err;
152
153 err = request_irq(IRQ_MAC_ADB, macii_interrupt, IRQ_FLG_LOCK, "ADB",
154 macii_interrupt);
155 if (err) return err;
156
157 macii_state = idle;
158 local_irq_restore(flags);
159 return 0;
160 }
161
162 /* initialize the hardware */
163 static int macii_init_via(void)
164 {
165 unsigned char x;
166
167 /* Set the lines up. We want TREQ as input TACK|TIP as output */
168 via[DIRB] = (via[DIRB] | TACK | TIP) & ~TREQ;
169
170 /* Set up state: idle */
171 via[B] |= ST_IDLE;
172 last_status = via[B] & (ST_MASK|TREQ);
173
174 /* Shift register on input */
175 via[ACR] = (via[ACR] & ~SR_CTRL) | SR_EXT;
176
177 /* Wipe any pending data and int */
178 x = via[SR];
179
180 return 0;
181 }
182
183 /* Send an ADB poll (Talk Register 0 command, tagged on the front of the request queue) */
184 static void macii_queue_poll(void)
185 {
186 static int device = 0;
187 static int in_poll=0;
188 static struct adb_request req;
189 unsigned long flags;
190
191 if (in_poll) printk("macii_queue_poll: double poll!\n");
192
193 in_poll++;
194 if (++device > 15) device = 1;
195
196 adb_request(&req, NULL, ADBREQ_REPLY|ADBREQ_NOSEND, 1,
197 ADB_READREG(device, 0));
198
199 local_irq_save(flags);
200
201 req.next = current_req;
202 current_req = &req;
203
204 local_irq_restore(flags);
205 macii_start();
206 in_poll--;
207 }
208
209 /* Send an ADB retransmit (Talk, appended to the request queue) */
210 static void macii_retransmit(int device)
211 {
212 static int in_retransmit = 0;
213 static struct adb_request rt;
214 unsigned long flags;
215
216 if (in_retransmit) printk("macii_retransmit: double retransmit!\n");
217
218 in_retransmit++;
219
220 adb_request(&rt, NULL, ADBREQ_REPLY|ADBREQ_NOSEND, 1,
221 ADB_READREG(device, 0));
222
223 local_irq_save(flags);
224
225 if (current_req != NULL) {
226 last_req->next = &rt;
227 last_req = &rt;
228 } else {
229 current_req = &rt;
230 last_req = &rt;
231 }
232
233 if (macii_state == idle) macii_start();
234
235 local_irq_restore(flags);
236 in_retransmit--;
237 }
238
239 /* Send an ADB request; if sync, poll out the reply 'till it's done */
240 static int macii_send_request(struct adb_request *req, int sync)
241 {
242 int i;
243
244 i = macii_write(req);
245 if (i) return i;
246
247 if (sync) {
248 while (!req->complete) macii_poll();
249 }
250 return 0;
251 }
252
253 /* Send an ADB request */
254 static int macii_write(struct adb_request *req)
255 {
256 unsigned long flags;
257
258 if (req->nbytes < 2 || req->data[0] != ADB_PACKET || req->nbytes > 15) {
259 req->complete = 1;
260 return -EINVAL;
261 }
262
263 req->next = NULL;
264 req->sent = 0;
265 req->complete = 0;
266 req->reply_len = 0;
267
268 local_irq_save(flags);
269
270 if (current_req != NULL) {
271 last_req->next = req;
272 last_req = req;
273 } else {
274 current_req = req;
275 last_req = req;
276 if (macii_state == idle) macii_start();
277 }
278
279 local_irq_restore(flags);
280 return 0;
281 }
282
283 /* Start auto-polling */
284 static int macii_autopoll(int devs)
285 {
286 /* Just ping a random default address */
287 if (!(current_req || retry_req))
288 macii_retransmit( (last_active < 16 && last_active > 0) ? last_active : 3);
289 return 0;
290 }
291
292 /* Prod the chip without interrupts */
293 static void macii_poll(void)
294 {
295 unsigned long flags;
296
297 local_irq_save(flags);
298 if (via[IFR] & SR_INT) macii_interrupt(0, NULL, NULL);
299 local_irq_restore(flags);
300 }
301
302 /* Reset the bus */
303 static int macii_reset_bus(void)
304 {
305 static struct adb_request req;
306
307 /* Command = 0, Address = ignored */
308 adb_request(&req, NULL, 0, 1, ADB_BUSRESET);
309
310 return 0;
311 }
312
313 /* Start sending ADB packet */
314 static void macii_start(void)
315 {
316 unsigned long flags;
317 struct adb_request *req;
318
319 req = current_req;
320 if (!req) return;
321
322 /* assert macii_state == idle */
323 if (macii_state != idle) {
324 printk("macii_start: called while driver busy (%p %x %x)!\n",
325 req, macii_state, (uint) via1[B] & (ST_MASK|TREQ));
326 return;
327 }
328
329 local_irq_save(flags);
330
331 /*
332 * IRQ signaled ?? (means ADB controller wants to send, or might
333 * be end of packet if we were reading)
334 */
335 #if 0 /* FIXME: This is broke broke broke, for some reason */
336 if ((via[B] & TREQ) == 0) {
337 printk("macii_start: weird poll stuff. huh?\n");
338 /*
339 * FIXME - we need to restart this on a timer
340 * or a collision at boot hangs us.
341 * Never set macii_state to idle here, or macii_start
342 * won't be called again from send_request!
343 * (need to re-check other cases ...)
344 */
345 /*
346 * if the interrupt handler set the need_poll
347 * flag, it's hopefully a SRQ poll or re-Talk
348 * so we try to send here anyway
349 */
350 if (!need_poll) {
351 if (console_loglevel == 10)
352 printk("macii_start: device busy - retry %p state %d status %x!\n",
353 req, macii_state,
354 (uint) via[B] & (ST_MASK|TREQ));
355 retry_req = req;
356 /* set ADB status here ? */
357 local_irq_restore(flags);
358 return;
359 } else {
360 need_poll = 0;
361 }
362 }
363 #endif
364 /*
365 * Another retry pending? (sanity check)
366 */
367 if (retry_req) {
368 retry_req = NULL;
369 }
370
371 /* Now send it. Be careful though, that first byte of the request */
372 /* is actually ADB_PACKET; the real data begins at index 1! */
373
374 /* store command byte */
375 command_byte = req->data[1];
376 /* Output mode */
377 via[ACR] |= SR_OUT;
378 /* Load data */
379 via[SR] = req->data[1];
380 /* set ADB state to 'command' */
381 via[B] = (via[B] & ~ST_MASK) | ST_CMD;
382
383 macii_state = sending;
384 data_index = 2;
385
386 local_irq_restore(flags);
387 }
388
389 /*
390 * The notorious ADB interrupt handler - does all of the protocol handling,
391 * except for starting new send operations. Relies heavily on the ADB
392 * controller sending and receiving data, thereby generating SR interrupts
393 * for us. This means there has to be always activity on the ADB bus, otherwise
394 * the whole process dies and has to be re-kicked by sending TALK requests ...
395 * CUDA-based Macs seem to solve this with the autopoll option, for MacII-type
396 * ADB the problem isn't solved yet (retransmit of the latest active TALK seems
397 * a good choice; either on timeout or on a timer interrupt).
398 *
399 * The basic ADB state machine was left unchanged from the original MacII code
400 * by Alan Cox, which was based on the CUDA driver for PowerMac.
401 * The syntax of the ADB status lines seems to be totally different on MacII,
402 * though. MacII uses the states Command -> Even -> Odd -> Even ->...-> Idle for
403 * sending, and Idle -> Even -> Odd -> Even ->...-> Idle for receiving. Start
404 * and end of a receive packet are signaled by asserting /IRQ on the interrupt
405 * line. Timeouts are signaled by a sequence of 4 0xFF, with /IRQ asserted on
406 * every other byte. SRQ is probably signaled by 3 or more 0xFF tacked on the
407 * end of a packet. (Thanks to Guido Koerber for eavesdropping on the ADB
408 * protocol with a logic analyzer!!)
409 *
410 * Note: As of 21/10/97, the MacII ADB part works including timeout detection
411 * and retransmit (Talk to the last active device).
412 */
413 static irqreturn_t macii_interrupt(int irq, void *arg, struct pt_regs *regs)
414 {
415 int x, adbdir;
416 unsigned long flags;
417 struct adb_request *req;
418
419 last_status = status;
420
421 /* prevent races due to SCSI enabling ints */
422 local_irq_save(flags);
423
424 if (driver_running) {
425 local_irq_restore(flags);
426 return IRQ_NONE;
427 }
428
429 driver_running = 1;
430
431 status = via[B] & (ST_MASK|TREQ);
432 adbdir = via[ACR] & SR_OUT;
433
434 switch (macii_state) {
435 case idle:
436 x = via[SR];
437 first_byte = x;
438 /* set ADB state = even for first data byte */
439 via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
440
441 reply_buf[0] = first_byte; /* was command_byte?? */
442 reply_ptr = reply_buf + 1;
443 reply_len = 1;
444 prefix_len = 1;
445 reading_reply = 0;
446
447 macii_state = reading;
448 break;
449
450 case awaiting_reply:
451 /* handshake etc. for II ?? */
452 x = via[SR];
453 first_byte = x;
454 /* set ADB state = even for first data byte */
455 via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
456
457 current_req->reply[0] = first_byte;
458 reply_ptr = current_req->reply + 1;
459 reply_len = 1;
460 prefix_len = 1;
461 reading_reply = 1;
462
463 macii_state = reading;
464 break;
465
466 case sending:
467 req = current_req;
468 if (data_index >= req->nbytes) {
469 /* print an error message if a listen command has no data */
470 if (((command_byte & 0x0C) == 0x08)
471 /* && (console_loglevel == 10) */
472 && (data_index == 2))
473 printk("MacII ADB: listen command with no data: %x!\n",
474 command_byte);
475 /* reset to shift in */
476 via[ACR] &= ~SR_OUT;
477 x = via[SR];
478 /* set ADB state idle - might get SRQ */
479 via[B] = (via[B] & ~ST_MASK) | ST_IDLE;
480
481 req->sent = 1;
482
483 if (req->reply_expected) {
484 macii_state = awaiting_reply;
485 } else {
486 req->complete = 1;
487 current_req = req->next;
488 if (req->done) (*req->done)(req);
489 macii_state = idle;
490 if (current_req || retry_req)
491 macii_start();
492 else
493 macii_retransmit((command_byte & 0xF0) >> 4);
494 }
495 } else {
496 via[SR] = req->data[data_index++];
497
498 if ( (via[B] & ST_MASK) == ST_CMD ) {
499 /* just sent the command byte, set to EVEN */
500 via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
501 } else {
502 /* invert state bits, toggle ODD/EVEN */
503 via[B] ^= ST_MASK;
504 }
505 }
506 break;
507
508 case reading:
509
510 /* timeout / SRQ handling for II hw */
511 if( (first_byte == 0xFF && (reply_len-prefix_len)==2
512 && memcmp(reply_ptr-2,"\xFF\xFF",2)==0) ||
513 ((reply_len-prefix_len)==3
514 && memcmp(reply_ptr-3,"\xFF\xFF\xFF",3)==0))
515 {
516 /*
517 * possible timeout (in fact, most probably a
518 * timeout, since SRQ can't be signaled without
519 * transfer on the bus).
520 * The last three bytes seen were FF, together
521 * with the starting byte (in case we started
522 * on 'idle' or 'awaiting_reply') this probably
523 * makes four. So this is mostl likely #5!
524 * The timeout signal is a pattern 1 0 1 0 0..
525 * on /INT, meaning we missed it :-(
526 */
527 x = via[SR];
528 if (x != 0xFF) printk("MacII ADB: mistaken timeout/SRQ!\n");
529
530 if ((status & TREQ) == (last_status & TREQ)) {
531 /* Not a timeout. Unsolicited SRQ? weird. */
532 /* Terminate the SRQ packet and poll */
533 need_poll = 1;
534 }
535 /* There's no packet to get, so reply is blank */
536 via[B] ^= ST_MASK;
537 reply_ptr -= (reply_len-prefix_len);
538 reply_len = prefix_len;
539 macii_state = read_done;
540 break;
541 } /* end timeout / SRQ handling for II hw. */
542
543 if((reply_len-prefix_len)>3
544 && memcmp(reply_ptr-3,"\xFF\xFF\xFF",3)==0)
545 {
546 /* SRQ tacked on data packet */
547 /* Terminate the packet (SRQ never ends) */
548 x = via[SR];
549 macii_state = read_done;
550 reply_len -= 3;
551 reply_ptr -= 3;
552 need_poll = 1;
553 /* need to continue; next byte not seen else */
554 } else {
555 /* Sanity check */
556 if (reply_len > 15) reply_len = 0;
557 /* read byte */
558 x = via[SR];
559 *reply_ptr = x;
560 reply_ptr++;
561 reply_len++;
562 }
563 /* The usual handshake ... */
564
565 /*
566 * NetBSD hints that the next to last byte
567 * is sent with IRQ !!
568 * Guido found out it's the last one (0x0),
569 * but IRQ should be asserted already.
570 * Problem with timeout detection: First
571 * transition to /IRQ might be second
572 * byte of timeout packet!
573 * Timeouts are signaled by 4x FF.
574 */
575 if (((status & TREQ) == 0) && (x == 0x00)) { /* != 0xFF */
576 /* invert state bits, toggle ODD/EVEN */
577 via[B] ^= ST_MASK;
578
579 /* adjust packet length */
580 reply_len--;
581 reply_ptr--;
582 macii_state = read_done;
583 } else {
584 /* not caught: ST_CMD */
585 /* required for re-entry 'reading'! */
586 if ((status & ST_MASK) == ST_IDLE) {
587 /* (in)sanity check - set even */
588 via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
589 } else {
590 /* invert state bits */
591 via[B] ^= ST_MASK;
592 }
593 }
594 break;
595
596 case read_done:
597 x = via[SR];
598 if (reading_reply) {
599 req = current_req;
600 req->reply_len = reply_ptr - req->reply;
601 req->complete = 1;
602 current_req = req->next;
603 if (req->done) (*req->done)(req);
604 } else {
605 adb_input(reply_buf, reply_ptr - reply_buf,
606 regs, 0);
607 }
608
609 /*
610 * remember this device ID; it's the latest we got a
611 * reply from!
612 */
613 last_reply = command_byte;
614 last_active = (command_byte & 0xF0) >> 4;
615
616 /* SRQ seen before, initiate poll now */
617 if (need_poll) {
618 macii_state = idle;
619 macii_queue_poll();
620 need_poll = 0;
621 break;
622 }
623
624 /* set ADB state to idle */
625 via[B] = (via[B] & ~ST_MASK) | ST_IDLE;
626
627 /* /IRQ seen, so the ADB controller has data for us */
628 if ((via[B] & TREQ) != 0) {
629 macii_state = reading;
630
631 reply_buf[0] = command_byte;
632 reply_ptr = reply_buf + 1;
633 reply_len = 1;
634 prefix_len = 1;
635 reading_reply = 0;
636 } else {
637 /* no IRQ, send next packet or wait */
638 macii_state = idle;
639 if (current_req)
640 macii_start();
641 else
642 macii_retransmit(last_active);
643 }
644 break;
645
646 default:
647 break;
648 }
649 /* reset mutex and interrupts */
650 driver_running = 0;
651 local_irq_restore(flags);
652 return IRQ_HANDLED;
653 }
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