1 /*
2 * 6522 Versatile Interface Adapter (VIA)
3 *
4 * There are two of these on the Mac II. Some IRQs are vectored
5 * via them as are assorted bits and bobs - eg RTC, ADB.
6 *
7 * CSA: Motorola seems to have removed documentation on the 6522 from
8 * their web site; try
9 * http://nerini.drf.com/vectrex/other/text/chips/6522/
10 * http://www.zymurgy.net/classic/vic20/vicdet1.htm
11 * and
12 * http://193.23.168.87/mikro_laborversuche/via_iobaustein/via6522_1.html
13 * for info. A full-text web search on 6522 AND VIA will probably also
14 * net some usefulness. <cananian@alumni.princeton.edu> 20apr1999
15 *
16 * Additional data is here (the SY6522 was used in the Mac II etc):
17 * http://www.6502.org/documents/datasheets/synertek/synertek_sy6522.pdf
18 * http://www.6502.org/documents/datasheets/synertek/synertek_sy6522_programming_reference.pdf
19 *
20 * PRAM/RTC access algorithms are from the NetBSD RTC toolkit version 1.08b
21 * by Erik Vogan and adapted to Linux by Joshua M. Thompson (funaho@jurai.org)
22 *
23 */
24
25 #include <linux/types.h>
26 #include <linux/kernel.h>
27 #include <linux/mm.h>
28 #include <linux/delay.h>
29 #include <linux/init.h>
30 #include <linux/module.h>
31 #include <linux/irq.h>
32
33 #include <asm/bootinfo.h>
34 #include <asm/macintosh.h>
35 #include <asm/macints.h>
36 #include <asm/mac_via.h>
37 #include <asm/mac_psc.h>
38 #include <asm/mac_oss.h>
39
40 volatile __u8 *via1, *via2;
41 int rbv_present;
42 int via_alt_mapping;
43 EXPORT_SYMBOL(via_alt_mapping);
44 static __u8 rbv_clear;
45
46 /*
47 * Globals for accessing the VIA chip registers without having to
48 * check if we're hitting a real VIA or an RBV. Normally you could
49 * just hit the combined register (ie, vIER|rIER) but that seems to
50 * break on AV Macs...probably because they actually decode more than
51 * eight address bits. Why can't Apple engineers at least be
52 * _consistently_ lazy? - 1999-05-21 (jmt)
53 */
54
55 static int gIER,gIFR,gBufA,gBufB;
56
57 /*
58 * Timer defs.
59 */
60
61 #define TICK_SIZE 10000
62 #define MAC_CLOCK_TICK (783300/HZ) /* ticks per HZ */
63 #define MAC_CLOCK_LOW (MAC_CLOCK_TICK&0xFF)
64 #define MAC_CLOCK_HIGH (MAC_CLOCK_TICK>>8)
65
66
67 /*
68 * On Macs with a genuine VIA chip there is no way to mask an individual slot
69 * interrupt. This limitation also seems to apply to VIA clone logic cores in
70 * Quadra-like ASICs. (RBV and OSS machines don't have this limitation.)
71 *
72 * We used to fake it by configuring the relevent VIA pin as an output
73 * (to mask the interrupt) or input (to unmask). That scheme did not work on
74 * (at least) the Quadra 700. A NuBus card's /NMRQ signal is an open-collector
75 * circuit (see Designing Cards and Drivers for Macintosh II and Macintosh SE,
76 * p. 10-11 etc) but VIA outputs are not (see datasheet).
77 *
78 * Driving these outputs high must cause the VIA to source current and the
79 * card to sink current when it asserts /NMRQ. Current will flow but the pin
80 * voltage is uncertain and so the /NMRQ condition may still cause a transition
81 * at the VIA2 CA1 input (which explains the lost interrupts). A side effect
82 * is that a disabled slot IRQ can never be tested as pending or not.
83 *
84 * Driving these outputs low doesn't work either. All the slot /NMRQ lines are
85 * (active low) OR'd together to generate the CA1 (aka "SLOTS") interrupt (see
86 * The Guide To Macintosh Family Hardware, 2nd edition p. 167). If we drive a
87 * disabled /NMRQ line low, the falling edge immediately triggers a CA1
88 * interrupt and all slot interrupts after that will generate no transition
89 * and therefore no interrupt, even after being re-enabled.
90 *
91 * So we make the VIA port A I/O lines inputs and use nubus_disabled to keep
92 * track of their states. When any slot IRQ becomes disabled we mask the CA1
93 * umbrella interrupt. Only when all slot IRQs become enabled do we unmask
94 * the CA1 interrupt. It must remain enabled even when cards have no interrupt
95 * handler registered. Drivers must therefore disable a slot interrupt at the
96 * device before they call free_irq (like shared and autovector interrupts).
97 *
98 * There is also a related problem when MacOS is used to boot Linux. A network
99 * card brought up by a MacOS driver may raise an interrupt while Linux boots.
100 * This can be fatal since it can't be handled until the right driver loads
101 * (if such a driver exists at all). Apparently related to this hardware
102 * limitation, "Designing Cards and Drivers", p. 9-8, says that a slot
103 * interrupt with no driver would crash MacOS (the book was written before
104 * the appearance of Macs with RBV or OSS).
105 */
106
107 static u8 nubus_disabled;
108
109 void via_debug_dump(void);
110
111 /*
112 * Initialize the VIAs
113 *
114 * First we figure out where they actually _are_ as well as what type of
115 * VIA we have for VIA2 (it could be a real VIA or an RBV or even an OSS.)
116 * Then we pretty much clear them out and disable all IRQ sources.
117 *
118 * Note: the OSS is actually "detected" here and not in oss_init(). It just
119 * seems more logical to do it here since via_init() needs to know
120 * these things anyways.
121 */
122
via_init(void)123 void __init via_init(void)
124 {
125 switch(macintosh_config->via_type) {
126
127 /* IIci, IIsi, IIvx, IIvi (P6xx), LC series */
128
129 case MAC_VIA_IICI:
130 via1 = (void *) VIA1_BASE;
131 if (macintosh_config->ident == MAC_MODEL_IIFX) {
132 via2 = NULL;
133 rbv_present = 0;
134 oss_present = 1;
135 } else {
136 via2 = (void *) RBV_BASE;
137 rbv_present = 1;
138 oss_present = 0;
139 }
140 if (macintosh_config->ident == MAC_MODEL_LCIII) {
141 rbv_clear = 0x00;
142 } else {
143 /* on most RBVs (& unlike the VIAs), you */
144 /* need to set bit 7 when you write to IFR */
145 /* in order for your clear to occur. */
146 rbv_clear = 0x80;
147 }
148 gIER = rIER;
149 gIFR = rIFR;
150 gBufA = rSIFR;
151 gBufB = rBufB;
152 break;
153
154 /* Quadra and early MacIIs agree on the VIA locations */
155
156 case MAC_VIA_QUADRA:
157 case MAC_VIA_II:
158 via1 = (void *) VIA1_BASE;
159 via2 = (void *) VIA2_BASE;
160 rbv_present = 0;
161 oss_present = 0;
162 rbv_clear = 0x00;
163 gIER = vIER;
164 gIFR = vIFR;
165 gBufA = vBufA;
166 gBufB = vBufB;
167 break;
168 default:
169 panic("UNKNOWN VIA TYPE");
170 }
171
172 printk(KERN_INFO "VIA1 at %p is a 6522 or clone\n", via1);
173
174 printk(KERN_INFO "VIA2 at %p is ", via2);
175 if (rbv_present) {
176 printk("an RBV\n");
177 } else if (oss_present) {
178 printk("an OSS\n");
179 } else {
180 printk("a 6522 or clone\n");
181 }
182
183 #ifdef DEBUG_VIA
184 via_debug_dump();
185 #endif
186
187 /*
188 * Shut down all IRQ sources, reset the timers, and
189 * kill the timer latch on VIA1.
190 */
191
192 via1[vIER] = 0x7F;
193 via1[vIFR] = 0x7F;
194 via1[vT1LL] = 0;
195 via1[vT1LH] = 0;
196 via1[vT1CL] = 0;
197 via1[vT1CH] = 0;
198 via1[vT2CL] = 0;
199 via1[vT2CH] = 0;
200 via1[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */
201 via1[vACR] &= ~0x03; /* disable port A & B latches */
202
203 /*
204 * SE/30: disable video IRQ
205 * XXX: testing for SE/30 VBL
206 */
207
208 if (macintosh_config->ident == MAC_MODEL_SE30) {
209 via1[vDirB] |= 0x40;
210 via1[vBufB] |= 0x40;
211 }
212
213 /*
214 * Set the RTC bits to a known state: all lines to outputs and
215 * RTC disabled (yes that's 0 to enable and 1 to disable).
216 */
217
218 via1[vDirB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk | VIA1B_vRTCData);
219 via1[vBufB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk);
220
221 /* Everything below this point is VIA2/RBV only... */
222
223 if (oss_present)
224 return;
225
226 if ((macintosh_config->via_type == MAC_VIA_QUADRA) &&
227 (macintosh_config->adb_type != MAC_ADB_PB1) &&
228 (macintosh_config->adb_type != MAC_ADB_PB2) &&
229 (macintosh_config->ident != MAC_MODEL_C660) &&
230 (macintosh_config->ident != MAC_MODEL_Q840)) {
231 via_alt_mapping = 1;
232 via1[vDirB] |= 0x40;
233 via1[vBufB] &= ~0x40;
234 } else {
235 via_alt_mapping = 0;
236 }
237
238 /*
239 * Now initialize VIA2. For RBV we just kill all interrupts;
240 * for a regular VIA we also reset the timers and stuff.
241 */
242
243 via2[gIER] = 0x7F;
244 via2[gIFR] = 0x7F | rbv_clear;
245 if (!rbv_present) {
246 via2[vT1LL] = 0;
247 via2[vT1LH] = 0;
248 via2[vT1CL] = 0;
249 via2[vT1CH] = 0;
250 via2[vT2CL] = 0;
251 via2[vT2CH] = 0;
252 via2[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */
253 via2[vACR] &= ~0x03; /* disable port A & B latches */
254 }
255
256 /* Everything below this point is VIA2 only... */
257
258 if (rbv_present)
259 return;
260
261 /*
262 * Set vPCR for control line interrupts.
263 *
264 * CA1 (SLOTS IRQ), CB1 (ASC IRQ): negative edge trigger.
265 *
266 * Macs with ESP SCSI have a negative edge triggered SCSI interrupt.
267 * Testing reveals that PowerBooks do too. However, the SE/30
268 * schematic diagram shows an active high NCR5380 IRQ line.
269 */
270
271 pr_debug("VIA2 vPCR is 0x%02X\n", via2[vPCR]);
272 if (macintosh_config->via_type == MAC_VIA_II) {
273 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, pos. edge */
274 via2[vPCR] = 0x66;
275 } else {
276 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, neg. edge */
277 via2[vPCR] = 0x22;
278 }
279 }
280
281 /*
282 * Start the 100 Hz clock
283 */
284
via_init_clock(irq_handler_t func)285 void __init via_init_clock(irq_handler_t func)
286 {
287 via1[vACR] |= 0x40;
288 via1[vT1LL] = MAC_CLOCK_LOW;
289 via1[vT1LH] = MAC_CLOCK_HIGH;
290 via1[vT1CL] = MAC_CLOCK_LOW;
291 via1[vT1CH] = MAC_CLOCK_HIGH;
292
293 if (request_irq(IRQ_MAC_TIMER_1, func, 0, "timer", func))
294 pr_err("Couldn't register %s interrupt\n", "timer");
295 }
296
297 /*
298 * Debugging dump, used in various places to see what's going on.
299 */
300
via_debug_dump(void)301 void via_debug_dump(void)
302 {
303 printk(KERN_DEBUG "VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
304 (uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]);
305 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n",
306 (uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]);
307 if (oss_present) {
308 printk(KERN_DEBUG "VIA2: <OSS>\n");
309 } else if (rbv_present) {
310 printk(KERN_DEBUG "VIA2: IFR = 0x%02X IER = 0x%02X\n",
311 (uint) via2[rIFR], (uint) via2[rIER]);
312 printk(KERN_DEBUG " SIFR = 0x%02X SIER = 0x%02X\n",
313 (uint) via2[rSIFR], (uint) via2[rSIER]);
314 } else {
315 printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
316 (uint) via2[vDirA], (uint) via2[vDirB],
317 (uint) via2[vACR]);
318 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n",
319 (uint) via2[vPCR],
320 (uint) via2[vIFR], (uint) via2[vIER]);
321 }
322 }
323
324 /*
325 * This is always executed with interrupts disabled.
326 *
327 * TBI: get time offset between scheduling timer ticks
328 */
329
mac_gettimeoffset(void)330 unsigned long mac_gettimeoffset (void)
331 {
332 unsigned long ticks, offset = 0;
333
334 /* read VIA1 timer 2 current value */
335 ticks = via1[vT1CL] | (via1[vT1CH] << 8);
336 /* The probability of underflow is less than 2% */
337 if (ticks > MAC_CLOCK_TICK - MAC_CLOCK_TICK / 50)
338 /* Check for pending timer interrupt in VIA1 IFR */
339 if (via1[vIFR] & 0x40) offset = TICK_SIZE;
340
341 ticks = MAC_CLOCK_TICK - ticks;
342 ticks = ticks * 10000L / MAC_CLOCK_TICK;
343
344 return ticks + offset;
345 }
346
347 /*
348 * Flush the L2 cache on Macs that have it by flipping
349 * the system into 24-bit mode for an instant.
350 */
351
via_flush_cache(void)352 void via_flush_cache(void)
353 {
354 via2[gBufB] &= ~VIA2B_vMode32;
355 via2[gBufB] |= VIA2B_vMode32;
356 }
357
358 /*
359 * Return the status of the L2 cache on a IIci
360 */
361
via_get_cache_disable(void)362 int via_get_cache_disable(void)
363 {
364 /* Safeguard against being called accidentally */
365 if (!via2) {
366 printk(KERN_ERR "via_get_cache_disable called on a non-VIA machine!\n");
367 return 1;
368 }
369
370 return (int) via2[gBufB] & VIA2B_vCDis;
371 }
372
373 /*
374 * Initialize VIA2 for Nubus access
375 */
376
via_nubus_init(void)377 void __init via_nubus_init(void)
378 {
379 /* unlock nubus transactions */
380
381 if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
382 (macintosh_config->adb_type != MAC_ADB_PB2)) {
383 /* set the line to be an output on non-RBV machines */
384 if (!rbv_present)
385 via2[vDirB] |= 0x02;
386
387 /* this seems to be an ADB bit on PMU machines */
388 /* according to MkLinux. -- jmt */
389 via2[gBufB] |= 0x02;
390 }
391
392 /*
393 * Disable the slot interrupts. On some hardware that's not possible.
394 * On some hardware it's unclear what all of these I/O lines do.
395 */
396
397 switch (macintosh_config->via_type) {
398 case MAC_VIA_II:
399 case MAC_VIA_QUADRA:
400 pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]);
401 break;
402 case MAC_VIA_IICI:
403 /* RBV. Disable all the slot interrupts. SIER works like IER. */
404 via2[rSIER] = 0x7F;
405 break;
406 }
407 }
408
via_nubus_irq_startup(int irq)409 void via_nubus_irq_startup(int irq)
410 {
411 int irq_idx = IRQ_IDX(irq);
412
413 switch (macintosh_config->via_type) {
414 case MAC_VIA_II:
415 case MAC_VIA_QUADRA:
416 /* Make the port A line an input. Probably redundant. */
417 if (macintosh_config->via_type == MAC_VIA_II) {
418 /* The top two bits are RAM size outputs. */
419 via2[vDirA] &= 0xC0 | ~(1 << irq_idx);
420 } else {
421 /* Allow NuBus slots 9 through F. */
422 via2[vDirA] &= 0x80 | ~(1 << irq_idx);
423 }
424 /* fall through */
425 case MAC_VIA_IICI:
426 via_irq_enable(irq);
427 break;
428 }
429 }
430
via_nubus_irq_shutdown(int irq)431 void via_nubus_irq_shutdown(int irq)
432 {
433 switch (macintosh_config->via_type) {
434 case MAC_VIA_II:
435 case MAC_VIA_QUADRA:
436 /* Ensure that the umbrella CA1 interrupt remains enabled. */
437 via_irq_enable(irq);
438 break;
439 case MAC_VIA_IICI:
440 via_irq_disable(irq);
441 break;
442 }
443 }
444
445 /*
446 * The generic VIA interrupt routines (shamelessly stolen from Alan Cox's
447 * via6522.c :-), disable/pending masks added.
448 */
449
via1_irq(unsigned int irq,struct irq_desc * desc)450 void via1_irq(unsigned int irq, struct irq_desc *desc)
451 {
452 int irq_num;
453 unsigned char irq_bit, events;
454
455 events = via1[vIFR] & via1[vIER] & 0x7F;
456 if (!events)
457 return;
458
459 irq_num = VIA1_SOURCE_BASE;
460 irq_bit = 1;
461 do {
462 if (events & irq_bit) {
463 via1[vIFR] = irq_bit;
464 generic_handle_irq(irq_num);
465 }
466 ++irq_num;
467 irq_bit <<= 1;
468 } while (events >= irq_bit);
469 }
470
via2_irq(unsigned int irq,struct irq_desc * desc)471 static void via2_irq(unsigned int irq, struct irq_desc *desc)
472 {
473 int irq_num;
474 unsigned char irq_bit, events;
475
476 events = via2[gIFR] & via2[gIER] & 0x7F;
477 if (!events)
478 return;
479
480 irq_num = VIA2_SOURCE_BASE;
481 irq_bit = 1;
482 do {
483 if (events & irq_bit) {
484 via2[gIFR] = irq_bit | rbv_clear;
485 generic_handle_irq(irq_num);
486 }
487 ++irq_num;
488 irq_bit <<= 1;
489 } while (events >= irq_bit);
490 }
491
492 /*
493 * Dispatch Nubus interrupts. We are called as a secondary dispatch by the
494 * VIA2 dispatcher as a fast interrupt handler.
495 */
496
via_nubus_irq(unsigned int irq,struct irq_desc * desc)497 void via_nubus_irq(unsigned int irq, struct irq_desc *desc)
498 {
499 int slot_irq;
500 unsigned char slot_bit, events;
501
502 events = ~via2[gBufA] & 0x7F;
503 if (rbv_present)
504 events &= via2[rSIER];
505 else
506 events &= ~via2[vDirA];
507 if (!events)
508 return;
509
510 do {
511 slot_irq = IRQ_NUBUS_F;
512 slot_bit = 0x40;
513 do {
514 if (events & slot_bit) {
515 events &= ~slot_bit;
516 generic_handle_irq(slot_irq);
517 }
518 --slot_irq;
519 slot_bit >>= 1;
520 } while (events);
521
522 /* clear the CA1 interrupt and make certain there's no more. */
523 via2[gIFR] = 0x02 | rbv_clear;
524 events = ~via2[gBufA] & 0x7F;
525 if (rbv_present)
526 events &= via2[rSIER];
527 else
528 events &= ~via2[vDirA];
529 } while (events);
530 }
531
532 /*
533 * Register the interrupt dispatchers for VIA or RBV machines only.
534 */
535
via_register_interrupts(void)536 void __init via_register_interrupts(void)
537 {
538 if (via_alt_mapping) {
539 /* software interrupt */
540 irq_set_chained_handler(IRQ_AUTO_1, via1_irq);
541 /* via1 interrupt */
542 irq_set_chained_handler(IRQ_AUTO_6, via1_irq);
543 } else {
544 irq_set_chained_handler(IRQ_AUTO_1, via1_irq);
545 }
546 irq_set_chained_handler(IRQ_AUTO_2, via2_irq);
547 irq_set_chained_handler(IRQ_MAC_NUBUS, via_nubus_irq);
548 }
549
via_irq_enable(int irq)550 void via_irq_enable(int irq) {
551 int irq_src = IRQ_SRC(irq);
552 int irq_idx = IRQ_IDX(irq);
553
554 #ifdef DEBUG_IRQUSE
555 printk(KERN_DEBUG "via_irq_enable(%d)\n", irq);
556 #endif
557
558 if (irq_src == 1) {
559 via1[vIER] = IER_SET_BIT(irq_idx);
560 } else if (irq_src == 2) {
561 if (irq != IRQ_MAC_NUBUS || nubus_disabled == 0)
562 via2[gIER] = IER_SET_BIT(irq_idx);
563 } else if (irq_src == 7) {
564 switch (macintosh_config->via_type) {
565 case MAC_VIA_II:
566 case MAC_VIA_QUADRA:
567 nubus_disabled &= ~(1 << irq_idx);
568 /* Enable the CA1 interrupt when no slot is disabled. */
569 if (!nubus_disabled)
570 via2[gIER] = IER_SET_BIT(1);
571 break;
572 case MAC_VIA_IICI:
573 /* On RBV, enable the slot interrupt.
574 * SIER works like IER.
575 */
576 via2[rSIER] = IER_SET_BIT(irq_idx);
577 break;
578 }
579 }
580 }
581
via_irq_disable(int irq)582 void via_irq_disable(int irq) {
583 int irq_src = IRQ_SRC(irq);
584 int irq_idx = IRQ_IDX(irq);
585
586 #ifdef DEBUG_IRQUSE
587 printk(KERN_DEBUG "via_irq_disable(%d)\n", irq);
588 #endif
589
590 if (irq_src == 1) {
591 via1[vIER] = IER_CLR_BIT(irq_idx);
592 } else if (irq_src == 2) {
593 via2[gIER] = IER_CLR_BIT(irq_idx);
594 } else if (irq_src == 7) {
595 switch (macintosh_config->via_type) {
596 case MAC_VIA_II:
597 case MAC_VIA_QUADRA:
598 nubus_disabled |= 1 << irq_idx;
599 if (nubus_disabled)
600 via2[gIER] = IER_CLR_BIT(1);
601 break;
602 case MAC_VIA_IICI:
603 via2[rSIER] = IER_CLR_BIT(irq_idx);
604 break;
605 }
606 }
607 }
608
via1_set_head(int head)609 void via1_set_head(int head)
610 {
611 if (head == 0)
612 via1[vBufA] &= ~VIA1A_vHeadSel;
613 else
614 via1[vBufA] |= VIA1A_vHeadSel;
615 }
616 EXPORT_SYMBOL(via1_set_head);
617
via2_scsi_drq_pending(void)618 int via2_scsi_drq_pending(void)
619 {
620 return via2[gIFR] & (1 << IRQ_IDX(IRQ_MAC_SCSIDRQ));
621 }
622 EXPORT_SYMBOL(via2_scsi_drq_pending);
623