aboutsummaryrefslogtreecommitdiff
path: root/arch/m68k/mac/macints.c
blob: 73b39cd3f94c965176017b3594b922ed2da55104 (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
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
/*
 *	Macintosh interrupts
 *
 * General design:
 * In contrary to the Amiga and Atari platforms, the Mac hardware seems to
 * exclusively use the autovector interrupts (the 'generic level0-level7'
 * interrupts with exception vectors 0x19-0x1f). The following interrupt levels
 * are used:
 *	1	- VIA1
 *		  - slot 0: one second interrupt (CA2)
 *		  - slot 1: VBlank (CA1)
 *		  - slot 2: ADB data ready (SR full)
 *		  - slot 3: ADB data  (CB2)
 *		  - slot 4: ADB clock (CB1)
 *		  - slot 5: timer 2
 *		  - slot 6: timer 1
 *		  - slot 7: status of IRQ; signals 'any enabled int.'
 *
 *	2	- VIA2 or RBV
 *		  - slot 0: SCSI DRQ (CA2)
 *		  - slot 1: NUBUS IRQ (CA1) need to read port A to find which
 *		  - slot 2: /EXP IRQ (only on IIci)
 *		  - slot 3: SCSI IRQ (CB2)
 *		  - slot 4: ASC IRQ (CB1)
 *		  - slot 5: timer 2 (not on IIci)
 *		  - slot 6: timer 1 (not on IIci)
 *		  - slot 7: status of IRQ; signals 'any enabled int.'
 *
 *	2	- OSS (IIfx only?)
 *		  - slot 0: SCSI interrupt
 *		  - slot 1: Sound interrupt
 *
 * Levels 3-6 vary by machine type. For VIA or RBV Macintoshes:
 *
 *	3	- unused (?)
 *
 *	4	- SCC (slot number determined by reading RR3 on the SSC itself)
 *		  - slot 1: SCC channel A
 *		  - slot 2: SCC channel B
 *
 *	5	- unused (?)
 *		  [serial errors or special conditions seem to raise level 6
 *		  interrupts on some models (LC4xx?)]
 *
 *	6	- off switch (?)
 *
 * For OSS Macintoshes (IIfx only at this point):
 *
 *	3	- Nubus interrupt
 *		  - slot 0: Slot $9
 *		  - slot 1: Slot $A
 *		  - slot 2: Slot $B
 *		  - slot 3: Slot $C
 *		  - slot 4: Slot $D
 *		  - slot 5: Slot $E
 *
 *	4	- SCC IOP
 *		  - slot 1: SCC channel A
 *		  - slot 2: SCC channel B
 *
 *	5	- ISM IOP (ADB?)
 *
 *	6	- unused
 *
 * For PSC Macintoshes (660AV, 840AV):
 *
 *	3	- PSC level 3
 *		  - slot 0: MACE
 *
 *	4	- PSC level 4
 *		  - slot 1: SCC channel A interrupt
 *		  - slot 2: SCC channel B interrupt
 *		  - slot 3: MACE DMA
 *
 *	5	- PSC level 5
 *
 *	6	- PSC level 6
 *
 * Finally we have good 'ole level 7, the non-maskable interrupt:
 *
 *	7	- NMI (programmer's switch on the back of some Macs)
 *		  Also RAM parity error on models which support it (IIc, IIfx?)
 *
 * The current interrupt logic looks something like this:
 *
 * - We install dispatchers for the autovector interrupts (1-7). These
 *   dispatchers are responsible for querying the hardware (the
 *   VIA/RBV/OSS/PSC chips) to determine the actual interrupt source. Using
 *   this information a machspec interrupt number is generated by placing the
 *   index of the interrupt hardware into the low three bits and the original
 *   autovector interrupt number in the upper 5 bits. The handlers for the
 *   resulting machspec interrupt are then called.
 *
 * - Nubus is a special case because its interrupts are hidden behind two
 *   layers of hardware. Nubus interrupts come in as index 1 on VIA #2,
 *   which translates to IRQ number 17. In this spot we install _another_
 *   dispatcher. This dispatcher finds the interrupting slot number (9-F) and
 *   then forms a new machspec interrupt number as above with the slot number
 *   minus 9 in the low three bits and the pseudo-level 7 in the upper five
 *   bits.  The handlers for this new machspec interrupt number are then
 *   called. This puts Nubus interrupts into the range 56-62.
 *
 * - The Baboon interrupts (used on some PowerBooks) are an even more special
 *   case. They're hidden behind the Nubus slot $C interrupt thus adding a
 *   third layer of indirection. Why oh why did the Apple engineers do that?
 *
 * - We support "fast" and "slow" handlers, just like the Amiga port. The
 *   fast handlers are called first and with all interrupts disabled. They
 *   are expected to execute quickly (hence the name). The slow handlers are
 *   called last with interrupts enabled and the interrupt level restored.
 *   They must therefore be reentrant.
 *
 *   TODO:
 *
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/kernel_stat.h>
#include <linux/interrupt.h> /* for intr_count */
#include <linux/delay.h>
#include <linux/seq_file.h>

#include <asm/system.h>
#include <asm/irq.h>
#include <asm/traps.h>
#include <asm/bootinfo.h>
#include <asm/machw.h>
#include <asm/macintosh.h>
#include <asm/mac_via.h>
#include <asm/mac_psc.h>
#include <asm/hwtest.h>
#include <asm/errno.h>
#include <asm/macints.h>

#define DEBUG_SPURIOUS
#define SHUTUP_SONIC

/*
 * The mac_irq_list array is an array of linked lists of irq_node_t nodes.
 * Each node contains one handler to be called whenever the interrupt
 * occurs, with fast handlers listed before slow handlers.
 */

irq_node_t *mac_irq_list[NUM_MAC_SOURCES];

/* SCC interrupt mask */

static int scc_mask;

/*
 * VIA/RBV hooks
 */

extern void via_init(void);
extern void via_register_interrupts(void);
extern void via_irq_enable(int);
extern void via_irq_disable(int);
extern void via_irq_clear(int);
extern int  via_irq_pending(int);

/*
 * OSS hooks
 */

extern int oss_present;

extern void oss_init(void);
extern void oss_register_interrupts(void);
extern void oss_irq_enable(int);
extern void oss_irq_disable(int);
extern void oss_irq_clear(int);
extern int  oss_irq_pending(int);

/*
 * PSC hooks
 */

extern int psc_present;

extern void psc_init(void);
extern void psc_register_interrupts(void);
extern void psc_irq_enable(int);
extern void psc_irq_disable(int);
extern void psc_irq_clear(int);
extern int  psc_irq_pending(int);

/*
 * IOP hooks
 */

extern void iop_register_interrupts(void);

/*
 * Baboon hooks
 */

extern int baboon_present;

extern void baboon_init(void);
extern void baboon_register_interrupts(void);
extern void baboon_irq_enable(int);
extern void baboon_irq_disable(int);
extern void baboon_irq_clear(int);
extern int  baboon_irq_pending(int);

/*
 * SCC interrupt routines
 */

static void scc_irq_enable(int);
static void scc_irq_disable(int);

/*
 * console_loglevel determines NMI handler function
 */

irqreturn_t mac_nmi_handler(int, void *, struct pt_regs *);
irqreturn_t mac_debug_handler(int, void *, struct pt_regs *);

/* #define DEBUG_MACINTS */

void mac_init_IRQ(void)
{
        int i;

#ifdef DEBUG_MACINTS
	printk("mac_init_IRQ(): Setting things up...\n");
#endif
	/* Initialize the IRQ handler lists. Initially each list is empty, */

	for (i = 0; i < NUM_MAC_SOURCES; i++) {
		mac_irq_list[i] = NULL;
	}

	scc_mask = 0;

	/* Make sure the SONIC interrupt is cleared or things get ugly */
#ifdef SHUTUP_SONIC
	printk("Killing onboard sonic... ");
	/* This address should hopefully be mapped already */
	if (hwreg_present((void*)(0x50f0a000))) {
		*(long *)(0x50f0a014) = 0x7fffL;
		*(long *)(0x50f0a010) = 0L;
	}
	printk("Done.\n");
#endif /* SHUTUP_SONIC */

	/*
	 * Now register the handlers for the master IRQ handlers
	 * at levels 1-7. Most of the work is done elsewhere.
	 */

	if (oss_present) {
		oss_register_interrupts();
	} else {
		via_register_interrupts();
	}
	if (psc_present) psc_register_interrupts();
	if (baboon_present) baboon_register_interrupts();
	iop_register_interrupts();
	cpu_request_irq(7, mac_nmi_handler, IRQ_FLG_LOCK, "NMI",
			mac_nmi_handler);
#ifdef DEBUG_MACINTS
	printk("mac_init_IRQ(): Done!\n");
#endif
}

/*
 * Routines to work with irq_node_t's on linked lists lifted from
 * the Amiga code written by Roman Zippel.
 */

static inline void mac_insert_irq(irq_node_t **list, irq_node_t *node)
{
	unsigned long flags;
	irq_node_t *cur;

	if (!node->dev_id)
		printk("%s: Warning: dev_id of %s is zero\n",
		       __FUNCTION__, node->devname);

	local_irq_save(flags);

	cur = *list;

	if (node->flags & IRQ_FLG_FAST) {
		node->flags &= ~IRQ_FLG_SLOW;
		while (cur && cur->flags & IRQ_FLG_FAST) {
			list = &cur->next;
			cur = cur->next;
		}
	} else if (node->flags & IRQ_FLG_SLOW) {
		while (cur) {
			list = &cur->next;
			cur = cur->next;
		}
	} else {
		while (cur && !(cur->flags & IRQ_FLG_SLOW)) {
			list = &cur->next;
			cur = cur->next;
		}
	}

	node->next = cur;
	*list = node;

	local_irq_restore(flags);
}

static inline void mac_delete_irq(irq_node_t **list, void *dev_id)
{
	unsigned long flags;
	irq_node_t *node;

	local_irq_save(flags);

	for (node = *list; node; list = &node->next, node = *list) {
		if (node->dev_id == dev_id) {
			*list = node->next;
			/* Mark it as free. */
			node->handler = NULL;
			local_irq_restore(flags);
			return;
		}
	}
	local_irq_restore(flags);
	printk ("%s: tried to remove invalid irq\n", __FUNCTION__);
}

/*
 * Call all the handlers for a given interrupt. Fast handlers are called
 * first followed by slow handlers.
 *
 * This code taken from the original Amiga code written by Roman Zippel.
 */

void mac_do_irq_list(int irq, struct pt_regs *fp)
{
	irq_node_t *node, *slow_nodes;
	unsigned long flags;

	kstat_cpu(0).irqs[irq]++;

#ifdef DEBUG_SPURIOUS
	if (!mac_irq_list[irq] && (console_loglevel > 7)) {
		printk("mac_do_irq_list: spurious interrupt %d!\n", irq);
		return;
	}
#endif

	/* serve first fast and normal handlers */
	for (node = mac_irq_list[irq];
	     node && (!(node->flags & IRQ_FLG_SLOW));
	     node = node->next)
		node->handler(irq, node->dev_id, fp);
	if (!node) return;
	local_save_flags(flags);
	local_irq_restore((flags & ~0x0700) | (fp->sr & 0x0700));
	/* if slow handlers exists, serve them now */
	slow_nodes = node;
	for (; node; node = node->next) {
		node->handler(irq, node->dev_id, fp);
	}
}

/*
 *  mac_enable_irq - enable an interrupt source
 * mac_disable_irq - disable an interrupt source
 *   mac_clear_irq - clears a pending interrupt
 * mac_pending_irq - Returns the pending status of an IRQ (nonzero = pending)
 *
 * These routines are just dispatchers to the VIA/OSS/PSC routines.
 */

void mac_enable_irq (unsigned int irq)
{
	int irq_src	= IRQ_SRC(irq);

	switch(irq_src) {
		case 1: via_irq_enable(irq);
			break;
		case 2:
		case 7: if (oss_present) {
				oss_irq_enable(irq);
			} else {
				via_irq_enable(irq);
			}
			break;
		case 3:
		case 4:
		case 5:
		case 6: if (psc_present) {
				psc_irq_enable(irq);
			} else if (oss_present) {
				oss_irq_enable(irq);
			} else if (irq_src == 4) {
				scc_irq_enable(irq);
			}
			break;
		case 8: if (baboon_present) {
				baboon_irq_enable(irq);
			}
			break;
	}
}

void mac_disable_irq (unsigned int irq)
{
	int irq_src	= IRQ_SRC(irq);

	switch(irq_src) {
		case 1: via_irq_disable(irq);
			break;
		case 2:
		case 7: if (oss_present) {
				oss_irq_disable(irq);
			} else {
				via_irq_disable(irq);
			}
			break;
		case 3:
		case 4:
		case 5:
		case 6: if (psc_present) {
				psc_irq_disable(irq);
			} else if (oss_present) {
				oss_irq_disable(irq);
			} else if (irq_src == 4) {
				scc_irq_disable(irq);
			}
			break;
		case 8: if (baboon_present) {
				baboon_irq_disable(irq);
			}
			break;
	}
}

void mac_clear_irq( unsigned int irq )
{
	switch(IRQ_SRC(irq)) {
		case 1: via_irq_clear(irq);
			break;
		case 2:
		case 7: if (oss_present) {
				oss_irq_clear(irq);
			} else {
				via_irq_clear(irq);
			}
			break;
		case 3:
		case 4:
		case 5:
		case 6: if (psc_present) {
				psc_irq_clear(irq);
			} else if (oss_present) {
				oss_irq_clear(irq);
			}
			break;
		case 8: if (baboon_present) {
				baboon_irq_clear(irq);
			}
			break;
	}
}

int mac_irq_pending( unsigned int irq )
{
	switch(IRQ_SRC(irq)) {
		case 1: return via_irq_pending(irq);
		case 2:
		case 7: if (oss_present) {
				return oss_irq_pending(irq);
			} else {
				return via_irq_pending(irq);
			}
		case 3:
		case 4:
		case 5:
		case 6: if (psc_present) {
				return psc_irq_pending(irq);
			} else if (oss_present) {
				return oss_irq_pending(irq);
			}
	}
	return 0;
}

/*
 * Add an interrupt service routine to an interrupt source.
 * Returns 0 on success.
 *
 * FIXME: You can register interrupts on nonexistent source (ie PSC4 on a
 *        non-PSC machine). We should return -EINVAL in those cases.
 */

int mac_request_irq(unsigned int irq,
		    irqreturn_t (*handler)(int, void *, struct pt_regs *),
		    unsigned long flags, const char *devname, void *dev_id)
{
	irq_node_t *node;

#ifdef DEBUG_MACINTS
	printk ("%s: irq %d requested for %s\n", __FUNCTION__, irq, devname);
#endif

	if (irq < VIA1_SOURCE_BASE) {
		return cpu_request_irq(irq, handler, flags, devname, dev_id);
	}

	if (irq >= NUM_MAC_SOURCES) {
		printk ("%s: unknown irq %d requested by %s\n",
		        __FUNCTION__, irq, devname);
	}

	/* Get a node and stick it onto the right list */

	if (!(node = new_irq_node())) return -ENOMEM;

	node->handler	= handler;
	node->flags	= flags;
	node->dev_id	= dev_id;
	node->devname	= devname;
	node->next	= NULL;
	mac_insert_irq(&mac_irq_list[irq], node);

	/* Now enable the IRQ source */

	mac_enable_irq(irq);

	return 0;
}

/*
 * Removes an interrupt service routine from an interrupt source.
 */

void mac_free_irq(unsigned int irq, void *dev_id)
{
#ifdef DEBUG_MACINTS
	printk ("%s: irq %d freed by %p\n", __FUNCTION__, irq, dev_id);
#endif

	if (irq < VIA1_SOURCE_BASE) {
		cpu_free_irq(irq, dev_id);
		return;
	}

	if (irq >= NUM_MAC_SOURCES) {
		printk ("%s: unknown irq %d freed\n",
		        __FUNCTION__, irq);
		return;
	}

	mac_delete_irq(&mac_irq_list[irq], dev_id);

	/* If the list for this interrupt is */
	/* empty then disable the source.    */

	if (!mac_irq_list[irq]) {
		mac_disable_irq(irq);
	}
}

/*
 * Generate a pretty listing for /proc/interrupts
 *
 * By the time we're called the autovector interrupt list has already been
 * generated, so we just need to do the machspec interrupts.
 *
 * 990506 (jmt) - rewritten to handle chained machspec interrupt handlers.
 *                Also removed display of num_spurious it is already
 *		  displayed for us as autovector irq 0.
 */

int show_mac_interrupts(struct seq_file *p, void *v)
{
	int i;
	irq_node_t *node;
	char *base;

	/* Don't do Nubus interrupts in this loop; we do them separately  */
	/* below so that we can print slot numbers instead of IRQ numbers */

	for (i = VIA1_SOURCE_BASE ; i < NUM_MAC_SOURCES ; ++i) {

		/* Nonexistant interrupt or nothing registered; skip it. */

		if ((node = mac_irq_list[i]) == NULL) continue;
		if (node->flags & IRQ_FLG_STD) continue;

		base = "";
		switch(IRQ_SRC(i)) {
			case 1: base = "via1";
				break;
			case 2: if (oss_present) {
					base = "oss";
				} else {
					base = "via2";
				}
				break;
			case 3:
			case 4:
			case 5:
			case 6: if (psc_present) {
					base = "psc";
				} else if (oss_present) {
					base = "oss";
				} else {
					if (IRQ_SRC(i) == 4) base = "scc";
				}
				break;
			case 7: base = "nbus";
				break;
			case 8: base = "bbn";
				break;
		}
		seq_printf(p, "%4s %2d: %10u ", base, i, kstat_cpu(0).irqs[i]);

		do {
			if (node->flags & IRQ_FLG_FAST) {
				seq_puts(p, "F ");
			} else if (node->flags & IRQ_FLG_SLOW) {
				seq_puts(p, "S ");
			} else {
				seq_puts(p, "  ");
			}
			seq_printf(p, "%s\n", node->devname);
			if ((node = node->next)) {
				seq_puts(p, "                    ");
			}
		} while(node);

	}
	return 0;
}

static int num_debug[8];

irqreturn_t mac_debug_handler(int irq, void *dev_id, struct pt_regs *regs)
{
	if (num_debug[irq] < 10) {
		printk("DEBUG: Unexpected IRQ %d\n", irq);
		num_debug[irq]++;
	}
	return IRQ_HANDLED;
}

static int in_nmi;
static volatile int nmi_hold;

irqreturn_t mac_nmi_handler(int irq, void *dev_id, struct pt_regs *fp)
{
	int i;
	/*
	 * generate debug output on NMI switch if 'debug' kernel option given
	 * (only works with Penguin!)
	 */

	in_nmi++;
	for (i=0; i<100; i++)
		udelay(1000);

	if (in_nmi == 1) {
		nmi_hold = 1;
		printk("... pausing, press NMI to resume ...");
	} else {
		printk(" ok!\n");
		nmi_hold = 0;
	}

	barrier();

	while (nmi_hold == 1)
		udelay(1000);

	if ( console_loglevel >= 8 ) {
#if 0
		show_state();
		printk("PC: %08lx\nSR: %04x  SP: %p\n", fp->pc, fp->sr, fp);
		printk("d0: %08lx    d1: %08lx    d2: %08lx    d3: %08lx\n",
		       fp->d0, fp->d1, fp->d2, fp->d3);
		printk("d4: %08lx    d5: %08lx    a0: %08lx    a1: %08lx\n",
		       fp->d4, fp->d5, fp->a0, fp->a1);

		if (STACK_MAGIC != *(unsigned long *)current->kernel_stack_page)
			printk("Corrupted stack page\n");
		printk("Process %s (pid: %d, stackpage=%08lx)\n",
			current->comm, current->pid, current->kernel_stack_page);
		if (intr_count == 1)
			dump_stack((struct frame *)fp);
#else
		/* printk("NMI "); */
#endif
	}
	in_nmi--;
	return IRQ_HANDLED;
}

/*
 * Simple routines for masking and unmasking
 * SCC interrupts in cases where this can't be
 * done in hardware (only the PSC can do that.)
 */

static void scc_irq_enable(int irq) {
	int irq_idx     = IRQ_IDX(irq);

	scc_mask |= (1 << irq_idx);
}

static void scc_irq_disable(int irq) {
	int irq_idx     = IRQ_IDX(irq);

	scc_mask &= ~(1 << irq_idx);
}

/*
 * SCC master interrupt handler. We have to do a bit of magic here
 * to figure out what channel gave us the interrupt; putting this
 * here is cleaner than hacking it into drivers/char/macserial.c.
 */

void mac_scc_dispatch(int irq, void *dev_id, struct pt_regs *regs)
{
	volatile unsigned char *scc = (unsigned char *) mac_bi_data.sccbase + 2;
	unsigned char reg;
	unsigned long flags;

	/* Read RR3 from the chip. Always do this on channel A */
	/* This must be an atomic operation so disable irqs.   */

	local_irq_save(flags);
	*scc = 3;
	reg = *scc;
	local_irq_restore(flags);

	/* Now dispatch. Bits 0-2 are for channel B and */
	/* bits 3-5 are for channel A. We can safely    */
	/* ignore the remaining bits here.              */
	/*                                              */
	/* Note that we're ignoring scc_mask for now.   */
	/* If we actually mask the ints then we tend to */
	/* get hammered by very persistent SCC irqs,    */
	/* and since they're autovector interrupts they */
	/* pretty much kill the system.                 */

	if (reg & 0x38) mac_do_irq_list(IRQ_SCCA, regs);
	if (reg & 0x07) mac_do_irq_list(IRQ_SCCB, regs);
}