summaryrefslogtreecommitdiffstats
path: root/arch/m68k/mac/via.c
blob: e198dec868e472e802768c5a9459e498e7623b00 (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
/*
 *	6522 Versatile Interface Adapter (VIA)
 *
 *	There are two of these on the Mac II. Some IRQs are vectored
 *	via them as are assorted bits and bobs - eg RTC, ADB.
 *
 * CSA: Motorola seems to have removed documentation on the 6522 from
 * their web site; try
 *     http://nerini.drf.com/vectrex/other/text/chips/6522/
 *     http://www.zymurgy.net/classic/vic20/vicdet1.htm
 * and
 *     http://193.23.168.87/mikro_laborversuche/via_iobaustein/via6522_1.html
 * for info.  A full-text web search on 6522 AND VIA will probably also
 * net some usefulness. <cananian@alumni.princeton.edu> 20apr1999
 *
 * Additional data is here (the SY6522 was used in the Mac II etc):
 *     http://www.6502.org/documents/datasheets/synertek/synertek_sy6522.pdf
 *     http://www.6502.org/documents/datasheets/synertek/synertek_sy6522_programming_reference.pdf
 *
 * PRAM/RTC access algorithms are from the NetBSD RTC toolkit version 1.08b
 * by Erik Vogan and adapted to Linux by Joshua M. Thompson (funaho@jurai.org)
 *
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/irq.h>

#include <asm/macintosh.h>
#include <asm/macints.h>
#include <asm/mac_via.h>
#include <asm/mac_psc.h>
#include <asm/mac_oss.h>

volatile __u8 *via1, *via2;
int rbv_present;
int via_alt_mapping;
EXPORT_SYMBOL(via_alt_mapping);
static __u8 rbv_clear;

/*
 * Globals for accessing the VIA chip registers without having to
 * check if we're hitting a real VIA or an RBV. Normally you could
 * just hit the combined register (ie, vIER|rIER) but that seems to
 * break on AV Macs...probably because they actually decode more than
 * eight address bits. Why can't Apple engineers at least be
 * _consistently_ lazy?                          - 1999-05-21 (jmt)
 */

static int gIER,gIFR,gBufA,gBufB;

/*
 * Timer defs.
 */

#define TICK_SIZE		10000
#define MAC_CLOCK_TICK		(783300/HZ)		/* ticks per HZ */
#define MAC_CLOCK_LOW		(MAC_CLOCK_TICK&0xFF)
#define MAC_CLOCK_HIGH		(MAC_CLOCK_TICK>>8)


/*
 * On Macs with a genuine VIA chip there is no way to mask an individual slot
 * interrupt. This limitation also seems to apply to VIA clone logic cores in
 * Quadra-like ASICs. (RBV and OSS machines don't have this limitation.)
 *
 * We used to fake it by configuring the relevent VIA pin as an output
 * (to mask the interrupt) or input (to unmask). That scheme did not work on
 * (at least) the Quadra 700. A NuBus card's /NMRQ signal is an open-collector
 * circuit (see Designing Cards and Drivers for Macintosh II and Macintosh SE,
 * p. 10-11 etc) but VIA outputs are not (see datasheet).
 *
 * Driving these outputs high must cause the VIA to source current and the
 * card to sink current when it asserts /NMRQ. Current will flow but the pin
 * voltage is uncertain and so the /NMRQ condition may still cause a transition
 * at the VIA2 CA1 input (which explains the lost interrupts). A side effect
 * is that a disabled slot IRQ can never be tested as pending or not.
 *
 * Driving these outputs low doesn't work either. All the slot /NMRQ lines are
 * (active low) OR'd together to generate the CA1 (aka "SLOTS") interrupt (see
 * The Guide To Macintosh Family Hardware, 2nd edition p. 167). If we drive a
 * disabled /NMRQ line low, the falling edge immediately triggers a CA1
 * interrupt and all slot interrupts after that will generate no transition
 * and therefore no interrupt, even after being re-enabled.
 *
 * So we make the VIA port A I/O lines inputs and use nubus_disabled to keep
 * track of their states. When any slot IRQ becomes disabled we mask the CA1
 * umbrella interrupt. Only when all slot IRQs become enabled do we unmask
 * the CA1 interrupt. It must remain enabled even when cards have no interrupt
 * handler registered. Drivers must therefore disable a slot interrupt at the
 * device before they call free_irq (like shared and autovector interrupts).
 *
 * There is also a related problem when MacOS is used to boot Linux. A network
 * card brought up by a MacOS driver may raise an interrupt while Linux boots.
 * This can be fatal since it can't be handled until the right driver loads
 * (if such a driver exists at all). Apparently related to this hardware
 * limitation, "Designing Cards and Drivers", p. 9-8, says that a slot
 * interrupt with no driver would crash MacOS (the book was written before
 * the appearance of Macs with RBV or OSS).
 */

static u8 nubus_disabled;

void via_debug_dump(void);

/*
 * Initialize the VIAs
 *
 * First we figure out where they actually _are_ as well as what type of
 * VIA we have for VIA2 (it could be a real VIA or an RBV or even an OSS.)
 * Then we pretty much clear them out and disable all IRQ sources.
 *
 * Note: the OSS is actually "detected" here and not in oss_init(). It just
 *	 seems more logical to do it here since via_init() needs to know
 *	 these things anyways.
 */

void __init via_init(void)
{
	switch(macintosh_config->via_type) {

		/* IIci, IIsi, IIvx, IIvi (P6xx), LC series */

		case MAC_VIA_IICI:
			via1 = (void *) VIA1_BASE;
			if (macintosh_config->ident == MAC_MODEL_IIFX) {
				via2 = NULL;
				rbv_present = 0;
				oss_present = 1;
			} else {
				via2 = (void *) RBV_BASE;
				rbv_present = 1;
				oss_present = 0;
			}
			if (macintosh_config->ident == MAC_MODEL_LCIII) {
				rbv_clear = 0x00;
			} else {
				/* on most RBVs (& unlike the VIAs), you   */
				/* need to set bit 7 when you write to IFR */
				/* in order for your clear to occur.       */
				rbv_clear = 0x80;
			}
			gIER = rIER;
			gIFR = rIFR;
			gBufA = rSIFR;
			gBufB = rBufB;
			break;

		/* Quadra and early MacIIs agree on the VIA locations */

		case MAC_VIA_QUADRA:
		case MAC_VIA_II:
			via1 = (void *) VIA1_BASE;
			via2 = (void *) VIA2_BASE;
			rbv_present = 0;
			oss_present = 0;
			rbv_clear = 0x00;
			gIER = vIER;
			gIFR = vIFR;
			gBufA = vBufA;
			gBufB = vBufB;
			break;
		default:
			panic("UNKNOWN VIA TYPE");
	}

	printk(KERN_INFO "VIA1 at %p is a 6522 or clone\n", via1);

	printk(KERN_INFO "VIA2 at %p is ", via2);
	if (rbv_present) {
		printk("an RBV\n");
	} else if (oss_present) {
		printk("an OSS\n");
	} else {
		printk("a 6522 or clone\n");
	}

#ifdef DEBUG_VIA
	via_debug_dump();
#endif

	/*
	 * Shut down all IRQ sources, reset the timers, and
	 * kill the timer latch on VIA1.
	 */

	via1[vIER] = 0x7F;
	via1[vIFR] = 0x7F;
	via1[vT1LL] = 0;
	via1[vT1LH] = 0;
	via1[vT1CL] = 0;
	via1[vT1CH] = 0;
	via1[vT2CL] = 0;
	via1[vT2CH] = 0;
	via1[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */
	via1[vACR] &= ~0x03; /* disable port A & B latches */

	/*
	 * SE/30: disable video IRQ
	 * XXX: testing for SE/30 VBL
	 */

	if (macintosh_config->ident == MAC_MODEL_SE30) {
		via1[vDirB] |= 0x40;
		via1[vBufB] |= 0x40;
	}

	/*
	 * Set the RTC bits to a known state: all lines to outputs and
	 * RTC disabled (yes that's 0 to enable and 1 to disable).
	 */

	via1[vDirB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk | VIA1B_vRTCData);
	via1[vBufB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk);

	/* Everything below this point is VIA2/RBV only... */

	if (oss_present)
		return;

	if ((macintosh_config->via_type == MAC_VIA_QUADRA) &&
	    (macintosh_config->adb_type != MAC_ADB_PB1) &&
	    (macintosh_config->adb_type != MAC_ADB_PB2) &&
	    (macintosh_config->ident    != MAC_MODEL_C660) &&
	    (macintosh_config->ident    != MAC_MODEL_Q840)) {
		via_alt_mapping = 1;
		via1[vDirB] |= 0x40;
		via1[vBufB] &= ~0x40;
	} else {
		via_alt_mapping = 0;
	}

	/*
	 * Now initialize VIA2. For RBV we just kill all interrupts;
	 * for a regular VIA we also reset the timers and stuff.
	 */

	via2[gIER] = 0x7F;
	via2[gIFR] = 0x7F | rbv_clear;
	if (!rbv_present) {
		via2[vT1LL] = 0;
		via2[vT1LH] = 0;
		via2[vT1CL] = 0;
		via2[vT1CH] = 0;
		via2[vT2CL] = 0;
		via2[vT2CH] = 0;
		via2[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */
		via2[vACR] &= ~0x03; /* disable port A & B latches */
	}

	/* Everything below this point is VIA2 only... */

	if (rbv_present)
		return;

	/*
	 * Set vPCR for control line interrupts.
	 *
	 * CA1 (SLOTS IRQ), CB1 (ASC IRQ): negative edge trigger.
	 *
	 * Macs with ESP SCSI have a negative edge triggered SCSI interrupt.
	 * Testing reveals that PowerBooks do too. However, the SE/30
	 * schematic diagram shows an active high NCR5380 IRQ line.
	 */

	pr_debug("VIA2 vPCR is 0x%02X\n", via2[vPCR]);
	if (macintosh_config->via_type == MAC_VIA_II) {
		/* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, pos. edge */
		via2[vPCR] = 0x66;
	} else {
		/* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, neg. edge */
		via2[vPCR] = 0x22;
	}
}

/*
 * Start the 100 Hz clock
 */

void __init via_init_clock(irq_handler_t func)
{
	via1[vACR] |= 0x40;
	via1[vT1LL] = MAC_CLOCK_LOW;
	via1[vT1LH] = MAC_CLOCK_HIGH;
	via1[vT1CL] = MAC_CLOCK_LOW;
	via1[vT1CH] = MAC_CLOCK_HIGH;

	if (request_irq(IRQ_MAC_TIMER_1, func, 0, "timer", func))
		pr_err("Couldn't register %s interrupt\n", "timer");
}

/*
 * Debugging dump, used in various places to see what's going on.
 */

void via_debug_dump(void)
{
	printk(KERN_DEBUG "VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
		(uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]);
	printk(KERN_DEBUG "         PCR = 0x%02X  IFR = 0x%02X IER = 0x%02X\n",
		(uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]);
	if (oss_present) {
		printk(KERN_DEBUG "VIA2: <OSS>\n");
	} else if (rbv_present) {
		printk(KERN_DEBUG "VIA2:  IFR = 0x%02X  IER = 0x%02X\n",
			(uint) via2[rIFR], (uint) via2[rIER]);
		printk(KERN_DEBUG "      SIFR = 0x%02X SIER = 0x%02X\n",
			(uint) via2[rSIFR], (uint) via2[rSIER]);
	} else {
		printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
			(uint) via2[vDirA], (uint) via2[vDirB],
			(uint) via2[vACR]);
		printk(KERN_DEBUG "         PCR = 0x%02X  IFR = 0x%02X IER = 0x%02X\n",
			(uint) via2[vPCR],
			(uint) via2[vIFR], (uint) via2[vIER]);
	}
}

/*
 * This is always executed with interrupts disabled.
 *
 * TBI: get time offset between scheduling timer ticks
 */

u32 mac_gettimeoffset(void)
{
	unsigned long ticks, offset = 0;

	/* read VIA1 timer 2 current value */
	ticks = via1[vT1CL] | (via1[vT1CH] << 8);
	/* The probability of underflow is less than 2% */
	if (ticks > MAC_CLOCK_TICK - MAC_CLOCK_TICK / 50)
		/* Check for pending timer interrupt in VIA1 IFR */
		if (via1[vIFR] & 0x40) offset = TICK_SIZE;

	ticks = MAC_CLOCK_TICK - ticks;
	ticks = ticks * 10000L / MAC_CLOCK_TICK;

	return (ticks + offset) * 1000;
}

/*
 * Flush the L2 cache on Macs that have it by flipping
 * the system into 24-bit mode for an instant.
 */

void via_flush_cache(void)
{
	via2[gBufB] &= ~VIA2B_vMode32;
	via2[gBufB] |= VIA2B_vMode32;
}

/*
 * Return the status of the L2 cache on a IIci
 */

int via_get_cache_disable(void)
{
	/* Safeguard against being called accidentally */
	if (!via2) {
		printk(KERN_ERR "via_get_cache_disable called on a non-VIA machine!\n");
		return 1;
	}

	return (int) via2[gBufB] & VIA2B_vCDis;
}

/*
 * Initialize VIA2 for Nubus access
 */

void __init via_nubus_init(void)
{
	/* unlock nubus transactions */

	if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
	    (macintosh_config->adb_type != MAC_ADB_PB2)) {
		/* set the line to be an output on non-RBV machines */
		if (!rbv_present)
			via2[vDirB] |= 0x02;

		/* this seems to be an ADB bit on PMU machines */
		/* according to MkLinux.  -- jmt               */
		via2[gBufB] |= 0x02;
	}

	/*
	 * Disable the slot interrupts. On some hardware that's not possible.
	 * On some hardware it's unclear what all of these I/O lines do.
	 */

	switch (macintosh_config->via_type) {
	case MAC_VIA_II:
	case MAC_VIA_QUADRA:
		pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]);
		break;
	case MAC_VIA_IICI:
		/* RBV. Disable all the slot interrupts. SIER works like IER. */
		via2[rSIER] = 0x7F;
		break;
	}
}

void via_nubus_irq_startup(int irq)
{
	int irq_idx = IRQ_IDX(irq);

	switch (macintosh_config->via_type) {
	case MAC_VIA_II:
	case MAC_VIA_QUADRA:
		/* Make the port A line an input. Probably redundant. */
		if (macintosh_config->via_type == MAC_VIA_II) {
			/* The top two bits are RAM size outputs. */
			via2[vDirA] &= 0xC0 | ~(1 << irq_idx);
		} else {
			/* Allow NuBus slots 9 through F. */
			via2[vDirA] &= 0x80 | ~(1 << irq_idx);
		}
		/* fall through */
	case MAC_VIA_IICI:
		via_irq_enable(irq);
		break;
	}
}

void via_nubus_irq_shutdown(int irq)
{
	switch (macintosh_config->via_type) {
	case MAC_VIA_II:
	case MAC_VIA_QUADRA:
		/* Ensure that the umbrella CA1 interrupt remains enabled. */
		via_irq_enable(irq);
		break;
	case MAC_VIA_IICI:
		via_irq_disable(irq);
		break;
	}
}

/*
 * The generic VIA interrupt routines (shamelessly stolen from Alan Cox's
 * via6522.c :-), disable/pending masks added.
 */

void via1_irq(unsigned int irq, struct irq_desc *desc)
{
	int irq_num;
	unsigned char irq_bit, events;

	events = via1[vIFR] & via1[vIER] & 0x7F;
	if (!events)
		return;

	irq_num = VIA1_SOURCE_BASE;
	irq_bit = 1;
	do {
		if (events & irq_bit) {
			via1[vIFR] = irq_bit;
			generic_handle_irq(irq_num);
		}
		++irq_num;
		irq_bit <<= 1;
	} while (events >= irq_bit);
}

static void via2_irq(unsigned int irq, struct irq_desc *desc)
{
	int irq_num;
	unsigned char irq_bit, events;

	events = via2[gIFR] & via2[gIER] & 0x7F;
	if (!events)
		return;

	irq_num = VIA2_SOURCE_BASE;
	irq_bit = 1;
	do {
		if (events & irq_bit) {
			via2[gIFR] = irq_bit | rbv_clear;
			generic_handle_irq(irq_num);
		}
		++irq_num;
		irq_bit <<= 1;
	} while (events >= irq_bit);
}

/*
 * Dispatch Nubus interrupts. We are called as a secondary dispatch by the
 * VIA2 dispatcher as a fast interrupt handler.
 */

void via_nubus_irq(unsigned int irq, struct irq_desc *desc)
{
	int slot_irq;
	unsigned char slot_bit, events;

	events = ~via2[gBufA] & 0x7F;
	if (rbv_present)
		events &= via2[rSIER];
	else
		events &= ~via2[vDirA];
	if (!events)
		return;

	do {
		slot_irq = IRQ_NUBUS_F;
		slot_bit = 0x40;
		do {
			if (events & slot_bit) {
				events &= ~slot_bit;
				generic_handle_irq(slot_irq);
			}
			--slot_irq;
			slot_bit >>= 1;
		} while (events);

 		/* clear the CA1 interrupt and make certain there's no more. */
		via2[gIFR] = 0x02 | rbv_clear;
		events = ~via2[gBufA] & 0x7F;
		if (rbv_present)
			events &= via2[rSIER];
		else
			events &= ~via2[vDirA];
	} while (events);
}

/*
 * Register the interrupt dispatchers for VIA or RBV machines only.
 */

void __init via_register_interrupts(void)
{
	if (via_alt_mapping) {
		/* software interrupt */
		irq_set_chained_handler(IRQ_AUTO_1, via1_irq);
		/* via1 interrupt */
		irq_set_chained_handler(IRQ_AUTO_6, via1_irq);
	} else {
		irq_set_chained_handler(IRQ_AUTO_1, via1_irq);
	}
	irq_set_chained_handler(IRQ_AUTO_2, via2_irq);
	irq_set_chained_handler(IRQ_MAC_NUBUS, via_nubus_irq);
}

void via_irq_enable(int irq) {
	int irq_src	= IRQ_SRC(irq);
	int irq_idx	= IRQ_IDX(irq);

#ifdef DEBUG_IRQUSE
	printk(KERN_DEBUG "via_irq_enable(%d)\n", irq);
#endif

	if (irq_src == 1) {
		via1[vIER] = IER_SET_BIT(irq_idx);
	} else if (irq_src == 2) {
		if (irq != IRQ_MAC_NUBUS || nubus_disabled == 0)
			via2[gIER] = IER_SET_BIT(irq_idx);
	} else if (irq_src == 7) {
		switch (macintosh_config->via_type) {
		case MAC_VIA_II:
		case MAC_VIA_QUADRA:
			nubus_disabled &= ~(1 << irq_idx);
			/* Enable the CA1 interrupt when no slot is disabled. */
			if (!nubus_disabled)
				via2[gIER] = IER_SET_BIT(1);
			break;
		case MAC_VIA_IICI:
			/* On RBV, enable the slot interrupt.
			 * SIER works like IER.
			 */
			via2[rSIER] = IER_SET_BIT(irq_idx);
			break;
		}
	}
}

void via_irq_disable(int irq) {
	int irq_src	= IRQ_SRC(irq);
	int irq_idx	= IRQ_IDX(irq);

#ifdef DEBUG_IRQUSE
	printk(KERN_DEBUG "via_irq_disable(%d)\n", irq);
#endif

	if (irq_src == 1) {
		via1[vIER] = IER_CLR_BIT(irq_idx);
	} else if (irq_src == 2) {
		via2[gIER] = IER_CLR_BIT(irq_idx);
	} else if (irq_src == 7) {
		switch (macintosh_config->via_type) {
		case MAC_VIA_II:
		case MAC_VIA_QUADRA:
			nubus_disabled |= 1 << irq_idx;
			if (nubus_disabled)
				via2[gIER] = IER_CLR_BIT(1);
			break;
		case MAC_VIA_IICI:
			via2[rSIER] = IER_CLR_BIT(irq_idx);
			break;
		}
	}
}

void via1_set_head(int head)
{
	if (head == 0)
		via1[vBufA] &= ~VIA1A_vHeadSel;
	else
		via1[vBufA] |= VIA1A_vHeadSel;
}
EXPORT_SYMBOL(via1_set_head);

int via2_scsi_drq_pending(void)
{
	return via2[gIFR] & (1 << IRQ_IDX(IRQ_MAC_SCSIDRQ));
}
EXPORT_SYMBOL(via2_scsi_drq_pending);
OpenPOWER on IntegriCloud