aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/macintosh/via-macii.c
blob: 5d88d5b0ad9931c3f400efbe5c2ec6c48d6ec0c2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
/*
 * Device driver for the via ADB on (many) Mac II-class machines
 *
 * Based on the original ADB keyboard handler Copyright (c) 1997 Alan Cox
 * Also derived from code Copyright (C) 1996 Paul Mackerras.
 *
 * With various updates provided over the years by Michael Schmitz,
 * Guideo Koerber and others.
 *
 * Rewrite for Unified ADB by Joshua M. Thompson (funaho@jurai.org)
 *
 * 1999-08-02 (jmt) - Initial rewrite for Unified ADB.
 * 2000-03-29 Tony Mantler <tonym@mac.linux-m68k.org>
 * 				- Big overhaul, should actually work now.
 */
 
#include <stdarg.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/adb.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <asm/macintosh.h>
#include <asm/macints.h>
#include <asm/machw.h>
#include <asm/mac_via.h>
#include <asm/io.h>
#include <asm/system.h>

static volatile unsigned char *via;

/* VIA registers - spaced 0x200 bytes apart */
#define RS		0x200		/* skip between registers */
#define B		0		/* B-side data */
#define A		RS		/* A-side data */
#define DIRB		(2*RS)		/* B-side direction (1=output) */
#define DIRA		(3*RS)		/* A-side direction (1=output) */
#define T1CL		(4*RS)		/* Timer 1 ctr/latch (low 8 bits) */
#define T1CH		(5*RS)		/* Timer 1 counter (high 8 bits) */
#define T1LL		(6*RS)		/* Timer 1 latch (low 8 bits) */
#define T1LH		(7*RS)		/* Timer 1 latch (high 8 bits) */
#define T2CL		(8*RS)		/* Timer 2 ctr/latch (low 8 bits) */
#define T2CH		(9*RS)		/* Timer 2 counter (high 8 bits) */
#define SR		(10*RS)		/* Shift register */
#define ACR		(11*RS)		/* Auxiliary control register */
#define PCR		(12*RS)		/* Peripheral control register */
#define IFR		(13*RS)		/* Interrupt flag register */
#define IER		(14*RS)		/* Interrupt enable register */
#define ANH		(15*RS)		/* A-side data, no handshake */

/* Bits in B data register: all active low */
#define TREQ		0x08		/* Transfer request (input) */
#define TACK		0x10		/* Transfer acknowledge (output) */
#define TIP		0x20		/* Transfer in progress (output) */
#define ST_MASK		0x30		/* mask for selecting ADB state bits */

/* Bits in ACR */
#define SR_CTRL		0x1c		/* Shift register control bits */
#define SR_EXT		0x0c		/* Shift on external clock */
#define SR_OUT		0x10		/* Shift out if 1 */

/* Bits in IFR and IER */
#define IER_SET		0x80		/* set bits in IER */
#define IER_CLR		0		/* clear bits in IER */
#define SR_INT		0x04		/* Shift register full/empty */
#define SR_DATA		0x08		/* Shift register data */
#define SR_CLOCK	0x10		/* Shift register clock */

/* ADB transaction states according to GMHW */
#define ST_CMD		0x00		/* ADB state: command byte */
#define ST_EVEN		0x10		/* ADB state: even data byte */
#define ST_ODD		0x20		/* ADB state: odd data byte */
#define ST_IDLE		0x30		/* ADB state: idle, nothing to send */

static int  macii_init_via(void);
static void macii_start(void);
static irqreturn_t macii_interrupt(int irq, void *arg);
static void macii_retransmit(int);
static void macii_queue_poll(void);

static int macii_probe(void);
static int macii_init(void);
static int macii_send_request(struct adb_request *req, int sync);
static int macii_write(struct adb_request *req);
static int macii_autopoll(int devs);
static void macii_poll(void);
static int macii_reset_bus(void);

struct adb_driver via_macii_driver = {
	"Mac II",
	macii_probe,
	macii_init,
	macii_send_request,
	macii_autopoll,
	macii_poll,
	macii_reset_bus
};

static enum macii_state {
	idle,
	sending,
	reading,
	read_done,
	awaiting_reply
} macii_state;

static int need_poll    = 0;
static int command_byte = 0;
static int last_reply   = 0;
static int last_active  = 0;

static struct adb_request *current_req;
static struct adb_request *last_req;
static struct adb_request *retry_req;
static unsigned char reply_buf[16];
static unsigned char *reply_ptr;
static int reply_len;
static int reading_reply;
static int data_index;
static int first_byte;
static int prefix_len;
static int status = ST_IDLE|TREQ;
static int last_status;
static int driver_running = 0;

/* debug level 10 required for ADB logging (should be && debug_adb, ideally) */

/* Check for MacII style ADB */
static int macii_probe(void)
{
	if (macintosh_config->adb_type != MAC_ADB_II) return -ENODEV;

	via = via1;

	printk("adb: Mac II ADB Driver v1.0 for Unified ADB\n");
	return 0;
}

/* Initialize the driver */
int macii_init(void)
{
	unsigned long flags;
	int err;
	
	local_irq_save(flags);
	
	err = macii_init_via();
	if (err) return err;

	err = request_irq(IRQ_MAC_ADB, macii_interrupt, IRQ_FLG_LOCK, "ADB",
			  macii_interrupt);
	if (err) return err;

	macii_state = idle;
	local_irq_restore(flags);
	return 0;
}

/* initialize the hardware */	
static int macii_init_via(void)
{
	unsigned char x;

	/* Set the lines up. We want TREQ as input TACK|TIP as output */
	via[DIRB] = (via[DIRB] | TACK | TIP) & ~TREQ;

	/* Set up state: idle */
	via[B] |= ST_IDLE;
	last_status = via[B] & (ST_MASK|TREQ);

	/* Shift register on input */
	via[ACR] = (via[ACR] & ~SR_CTRL) | SR_EXT;

	/* Wipe any pending data and int */
	x = via[SR];

	return 0;
}

/* Send an ADB poll (Talk Register 0 command, tagged on the front of the request queue) */
static void macii_queue_poll(void)
{
	static int device = 0;
	static int in_poll=0;
	static struct adb_request req;
	unsigned long flags;
	
	if (in_poll) printk("macii_queue_poll: double poll!\n");

	in_poll++;
	if (++device > 15) device = 1;

	adb_request(&req, NULL, ADBREQ_REPLY|ADBREQ_NOSEND, 1,
		    ADB_READREG(device, 0));

	local_irq_save(flags);

	req.next = current_req;
	current_req = &req;

	local_irq_restore(flags);
	macii_start();
	in_poll--;
}

/* Send an ADB retransmit (Talk, appended to the request queue) */
static void macii_retransmit(int device)
{
	static int in_retransmit = 0;
	static struct adb_request rt;
	unsigned long flags;
	
	if (in_retransmit) printk("macii_retransmit: double retransmit!\n");

	in_retransmit++;

	adb_request(&rt, NULL, ADBREQ_REPLY|ADBREQ_NOSEND, 1,
		    ADB_READREG(device, 0));

	local_irq_save(flags);

	if (current_req != NULL) {
		last_req->next = &rt;
		last_req = &rt;
	} else {
		current_req = &rt;
		last_req = &rt;
	}

	if (macii_state == idle) macii_start();

	local_irq_restore(flags);
	in_retransmit--;
}

/* Send an ADB request; if sync, poll out the reply 'till it's done */
static int macii_send_request(struct adb_request *req, int sync)
{
	int i;

	i = macii_write(req);
	if (i) return i;

	if (sync) {
		while (!req->complete) macii_poll();
	}
	return 0;
}

/* Send an ADB request */
static int macii_write(struct adb_request *req)
{
	unsigned long flags;

	if (req->nbytes < 2 || req->data[0] != ADB_PACKET || req->nbytes > 15) {
		req->complete = 1;
		return -EINVAL;
	}
	
	req->next = NULL;
	req->sent = 0;
	req->complete = 0;
	req->reply_len = 0;

	local_irq_save(flags);

	if (current_req != NULL) {
		last_req->next = req;
		last_req = req;
	} else {
		current_req = req;
		last_req = req;
		if (macii_state == idle) macii_start();
	}

	local_irq_restore(flags);
	return 0;
}

/* Start auto-polling */
static int macii_autopoll(int devs)
{
	/* Just ping a random default address */
	if (!(current_req || retry_req))
		macii_retransmit( (last_active < 16 && last_active > 0) ? last_active : 3);
	return 0;
}

/* Prod the chip without interrupts */
static void macii_poll(void)
{
	unsigned long flags;

	local_irq_save(flags);
	if (via[IFR] & SR_INT) macii_interrupt(0, NULL);
	local_irq_restore(flags);
}

/* Reset the bus */
static int macii_reset_bus(void)
{
	static struct adb_request req;
	
	/* Command = 0, Address = ignored */
	adb_request(&req, NULL, 0, 1, ADB_BUSRESET);

	return 0;
}

/* Start sending ADB packet */
static void macii_start(void)
{
	unsigned long flags;
	struct adb_request *req;

	req = current_req;
	if (!req) return;
	
	/* assert macii_state == idle */
	if (macii_state != idle) {
		printk("macii_start: called while driver busy (%p %x %x)!\n",
			req, macii_state, (uint) via1[B] & (ST_MASK|TREQ));
		return;
	}

	local_irq_save(flags);
	
	/* 
	 * IRQ signaled ?? (means ADB controller wants to send, or might 
	 * be end of packet if we were reading)
	 */
#if 0 /* FIXME: This is broke broke broke, for some reason */
	if ((via[B] & TREQ) == 0) {
		printk("macii_start: weird poll stuff. huh?\n");
		/*
		 *	FIXME - we need to restart this on a timer
		 *	or a collision at boot hangs us.
		 *	Never set macii_state to idle here, or macii_start 
		 *	won't be called again from send_request!
		 *	(need to re-check other cases ...)
		 */
		/*
		 * if the interrupt handler set the need_poll
		 * flag, it's hopefully a SRQ poll or re-Talk
		 * so we try to send here anyway
		 */
		if (!need_poll) {
			if (console_loglevel == 10)
				printk("macii_start: device busy - retry %p state %d status %x!\n", 
					req, macii_state,
					(uint) via[B] & (ST_MASK|TREQ));
			retry_req = req;
			/* set ADB status here ? */
			local_irq_restore(flags);
			return;
		} else {
			need_poll = 0;
		}
	}
#endif
	/*
	 * Another retry pending? (sanity check)
	 */
	if (retry_req) {
		retry_req = NULL;
	}

	/* Now send it. Be careful though, that first byte of the request */
	/* is actually ADB_PACKET; the real data begins at index 1!	  */
	
	/* store command byte */
	command_byte = req->data[1];
	/* Output mode */
	via[ACR] |= SR_OUT;
	/* Load data */
	via[SR] = req->data[1];
	/* set ADB state to 'command' */
	via[B] = (via[B] & ~ST_MASK) | ST_CMD;

	macii_state = sending;
	data_index = 2;

	local_irq_restore(flags);
}

/*
 * The notorious ADB interrupt handler - does all of the protocol handling, 
 * except for starting new send operations. Relies heavily on the ADB 
 * controller sending and receiving data, thereby generating SR interrupts
 * for us. This means there has to be always activity on the ADB bus, otherwise
 * the whole process dies and has to be re-kicked by sending TALK requests ...
 * CUDA-based Macs seem to solve this with the autopoll option, for MacII-type
 * ADB the problem isn't solved yet (retransmit of the latest active TALK seems
 * a good choice; either on timeout or on a timer interrupt).
 *
 * The basic ADB state machine was left unchanged from the original MacII code
 * by Alan Cox, which was based on the CUDA driver for PowerMac. 
 * The syntax of the ADB status lines seems to be totally different on MacII, 
 * though. MacII uses the states Command -> Even -> Odd -> Even ->...-> Idle for
 * sending, and Idle -> Even -> Odd -> Even ->...-> Idle for receiving. Start 
 * and end of a receive packet are signaled by asserting /IRQ on the interrupt
 * line. Timeouts are signaled by a sequence of 4 0xFF, with /IRQ asserted on 
 * every other byte. SRQ is probably signaled by 3 or more 0xFF tacked on the 
 * end of a packet. (Thanks to Guido Koerber for eavesdropping on the ADB 
 * protocol with a logic analyzer!!)
 *
 * Note: As of 21/10/97, the MacII ADB part works including timeout detection
 * and retransmit (Talk to the last active device).
 */
static irqreturn_t macii_interrupt(int irq, void *arg)
{
	int x, adbdir;
	unsigned long flags;
	struct adb_request *req;

	last_status = status;

	/* prevent races due to SCSI enabling ints */
	local_irq_save(flags);

	if (driver_running) {
		local_irq_restore(flags);
		return IRQ_NONE;
	}

	driver_running = 1;
	
	status = via[B] & (ST_MASK|TREQ);
	adbdir = via[ACR] & SR_OUT;

	switch (macii_state) {
		case idle:
			x = via[SR];
			first_byte = x;
			/* set ADB state = even for first data byte */
			via[B] = (via[B] & ~ST_MASK) | ST_EVEN;

			reply_buf[0] = first_byte; /* was command_byte?? */
			reply_ptr = reply_buf + 1;
			reply_len = 1;
			prefix_len = 1;
			reading_reply = 0;
			
			macii_state = reading;
			break;

		case awaiting_reply:
			/* handshake etc. for II ?? */
			x = via[SR];
			first_byte = x;
			/* set ADB state = even for first data byte */
			via[B] = (via[B] & ~ST_MASK) | ST_EVEN;

			current_req->reply[0] = first_byte;
			reply_ptr = current_req->reply + 1;
			reply_len = 1;
			prefix_len = 1;
			reading_reply = 1;

			macii_state = reading;			
			break;

		case sending:
			req = current_req;
			if (data_index >= req->nbytes) {
				/* print an error message if a listen command has no data */
				if (((command_byte & 0x0C) == 0x08)
				 /* && (console_loglevel == 10) */
				    && (data_index == 2))
					printk("MacII ADB: listen command with no data: %x!\n", 
						command_byte);
				/* reset to shift in */
				via[ACR] &= ~SR_OUT;
				x = via[SR];
				/* set ADB state idle - might get SRQ */
				via[B] = (via[B] & ~ST_MASK) | ST_IDLE;

				req->sent = 1;

				if (req->reply_expected) {
					macii_state = awaiting_reply;
				} else {
					req->complete = 1;
					current_req = req->next;
					if (req->done) (*req->done)(req);
					macii_state = idle;
					if (current_req || retry_req)
						macii_start();
					else
						macii_retransmit((command_byte & 0xF0) >> 4);
				}
			} else {
				via[SR] = req->data[data_index++];

				if ( (via[B] & ST_MASK) == ST_CMD ) {
					/* just sent the command byte, set to EVEN */
					via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
				} else {
					/* invert state bits, toggle ODD/EVEN */
					via[B] ^= ST_MASK;
				}
			}
			break;

		case reading:

			/* timeout / SRQ handling for II hw */
			if( (first_byte == 0xFF && (reply_len-prefix_len)==2 
			     && memcmp(reply_ptr-2,"\xFF\xFF",2)==0) || 
			    ((reply_len-prefix_len)==3 
			     && memcmp(reply_ptr-3,"\xFF\xFF\xFF",3)==0))
			{
				/*
				 * possible timeout (in fact, most probably a 
				 * timeout, since SRQ can't be signaled without
				 * transfer on the bus).
				 * The last three bytes seen were FF, together 
				 * with the starting byte (in case we started
				 * on 'idle' or 'awaiting_reply') this probably
				 * makes four. So this is mostl likely #5!
				 * The timeout signal is a pattern 1 0 1 0 0..
				 * on /INT, meaning we missed it :-(
				 */
				x = via[SR];
				if (x != 0xFF) printk("MacII ADB: mistaken timeout/SRQ!\n");

				if ((status & TREQ) == (last_status & TREQ)) {
					/* Not a timeout. Unsolicited SRQ? weird. */
					/* Terminate the SRQ packet and poll */
					need_poll = 1;
				}
				/* There's no packet to get, so reply is blank */
				via[B] ^= ST_MASK;
				reply_ptr -= (reply_len-prefix_len);
				reply_len = prefix_len;
				macii_state = read_done;
				break;
			} /* end timeout / SRQ handling for II hw. */

			if((reply_len-prefix_len)>3
				&& memcmp(reply_ptr-3,"\xFF\xFF\xFF",3)==0)
			{
				/* SRQ tacked on data packet */
				/* Terminate the packet (SRQ never ends) */
				x = via[SR];
				macii_state = read_done;
				reply_len -= 3;
				reply_ptr -= 3;
				need_poll = 1;
				/* need to continue; next byte not seen else */
			} else {
				/* Sanity check */
				if (reply_len > 15) reply_len = 0;
				/* read byte */
				x = via[SR];
				*reply_ptr = x;
				reply_ptr++;
				reply_len++;
			}
			/* The usual handshake ... */

			/*
			 * NetBSD hints that the next to last byte 
			 * is sent with IRQ !! 
			 * Guido found out it's the last one (0x0),
			 * but IRQ should be asserted already.
			 * Problem with timeout detection: First
			 * transition to /IRQ might be second 
			 * byte of timeout packet! 
			 * Timeouts are signaled by 4x FF.
			 */
			if (((status & TREQ) == 0) && (x == 0x00)) { /* != 0xFF */
				/* invert state bits, toggle ODD/EVEN */
				via[B] ^= ST_MASK;

				/* adjust packet length */
				reply_len--;
				reply_ptr--;
				macii_state = read_done;
			} else {
				/* not caught: ST_CMD */
				/* required for re-entry 'reading'! */
				if ((status & ST_MASK) == ST_IDLE) {
					/* (in)sanity check - set even */
					via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
				} else {
					/* invert state bits */
					via[B] ^= ST_MASK;
				}
			}
			break;

		case read_done:
			x = via[SR];
			if (reading_reply) {
				req = current_req;
				req->reply_len = reply_ptr - req->reply;
				req->complete = 1;
				current_req = req->next;
				if (req->done) (*req->done)(req);
			} else {
				adb_input(reply_buf, reply_ptr - reply_buf, 0);
			}

			/*
			 * remember this device ID; it's the latest we got a 
			 * reply from!
			 */
			last_reply = command_byte;
			last_active = (command_byte & 0xF0) >> 4;

			/* SRQ seen before, initiate poll now */
			if (need_poll) {
				macii_state = idle;
				macii_queue_poll();
				need_poll = 0;
				break;
			}
			
			/* set ADB state to idle */
			via[B] = (via[B] & ~ST_MASK) | ST_IDLE;
			
			/* /IRQ seen, so the ADB controller has data for us */
			if ((via[B] & TREQ) != 0) {
				macii_state = reading;

				reply_buf[0] = command_byte;
				reply_ptr = reply_buf + 1;
				reply_len = 1;
				prefix_len = 1;
				reading_reply = 0;
			} else {
				/* no IRQ, send next packet or wait */
				macii_state = idle;
				if (current_req)
					macii_start();
				else
					macii_retransmit(last_active);
			}
			break;

		default:
		break;
	}
	/* reset mutex and interrupts */
	driver_running = 0;
	local_irq_restore(flags);
	return IRQ_HANDLED;
}