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/macintosh.h>
34 #include <asm/macints.h>
35 #include <asm/mac_via.h>
36 #include <asm/mac_psc.h>
37 #include <asm/mac_oss.h>
38
39 volatile __u8 *via1, *via2;
40 int rbv_present;
41 int via_alt_mapping;
42 EXPORT_SYMBOL(via_alt_mapping);
43 static __u8 rbv_clear;
44
45 /*
46 * Globals for accessing the VIA chip registers without having to
47 * check if we're hitting a real VIA or an RBV. Normally you could
48 * just hit the combined register (ie, vIER|rIER) but that seems to
49 * break on AV Macs...probably because they actually decode more than
50 * eight address bits. Why can't Apple engineers at least be
51 * _consistently_ lazy? - 1999-05-21 (jmt)
52 */
53
54 static int gIER,gIFR,gBufA,gBufB;
55
56 /*
57 * On Macs with a genuine VIA chip there is no way to mask an individual slot
58 * interrupt. This limitation also seems to apply to VIA clone logic cores in
59 * Quadra-like ASICs. (RBV and OSS machines don't have this limitation.)
60 *
61 * We used to fake it by configuring the relevent VIA pin as an output
62 * (to mask the interrupt) or input (to unmask). That scheme did not work on
63 * (at least) the Quadra 700. A NuBus card's /NMRQ signal is an open-collector
64 * circuit (see Designing Cards and Drivers for Macintosh II and Macintosh SE,
65 * p. 10-11 etc) but VIA outputs are not (see datasheet).
66 *
67 * Driving these outputs high must cause the VIA to source current and the
68 * card to sink current when it asserts /NMRQ. Current will flow but the pin
69 * voltage is uncertain and so the /NMRQ condition may still cause a transition
70 * at the VIA2 CA1 input (which explains the lost interrupts). A side effect
71 * is that a disabled slot IRQ can never be tested as pending or not.
72 *
73 * Driving these outputs low doesn't work either. All the slot /NMRQ lines are
74 * (active low) OR'd together to generate the CA1 (aka "SLOTS") interrupt (see
75 * The Guide To Macintosh Family Hardware, 2nd edition p. 167). If we drive a
76 * disabled /NMRQ line low, the falling edge immediately triggers a CA1
77 * interrupt and all slot interrupts after that will generate no transition
78 * and therefore no interrupt, even after being re-enabled.
79 *
80 * So we make the VIA port A I/O lines inputs and use nubus_disabled to keep
81 * track of their states. When any slot IRQ becomes disabled we mask the CA1
82 * umbrella interrupt. Only when all slot IRQs become enabled do we unmask
83 * the CA1 interrupt. It must remain enabled even when cards have no interrupt
84 * handler registered. Drivers must therefore disable a slot interrupt at the
85 * device before they call free_irq (like shared and autovector interrupts).
86 *
87 * There is also a related problem when MacOS is used to boot Linux. A network
88 * card brought up by a MacOS driver may raise an interrupt while Linux boots.
89 * This can be fatal since it can't be handled until the right driver loads
90 * (if such a driver exists at all). Apparently related to this hardware
91 * limitation, "Designing Cards and Drivers", p. 9-8, says that a slot
92 * interrupt with no driver would crash MacOS (the book was written before
93 * the appearance of Macs with RBV or OSS).
94 */
95
96 static u8 nubus_disabled;
97
98 void via_debug_dump(void);
99
100 /*
101 * Initialize the VIAs
102 *
103 * First we figure out where they actually _are_ as well as what type of
104 * VIA we have for VIA2 (it could be a real VIA or an RBV or even an OSS.)
105 * Then we pretty much clear them out and disable all IRQ sources.
106 *
107 * Note: the OSS is actually "detected" here and not in oss_init(). It just
108 * seems more logical to do it here since via_init() needs to know
109 * these things anyways.
110 */
111
via_init(void)112 void __init via_init(void)
113 {
114 switch(macintosh_config->via_type) {
115
116 /* IIci, IIsi, IIvx, IIvi (P6xx), LC series */
117
118 case MAC_VIA_IICI:
119 via1 = (void *) VIA1_BASE;
120 if (macintosh_config->ident == MAC_MODEL_IIFX) {
121 via2 = NULL;
122 rbv_present = 0;
123 oss_present = 1;
124 } else {
125 via2 = (void *) RBV_BASE;
126 rbv_present = 1;
127 oss_present = 0;
128 }
129 if (macintosh_config->ident == MAC_MODEL_LCIII) {
130 rbv_clear = 0x00;
131 } else {
132 /* on most RBVs (& unlike the VIAs), you */
133 /* need to set bit 7 when you write to IFR */
134 /* in order for your clear to occur. */
135 rbv_clear = 0x80;
136 }
137 gIER = rIER;
138 gIFR = rIFR;
139 gBufA = rSIFR;
140 gBufB = rBufB;
141 break;
142
143 /* Quadra and early MacIIs agree on the VIA locations */
144
145 case MAC_VIA_QUADRA:
146 case MAC_VIA_II:
147 via1 = (void *) VIA1_BASE;
148 via2 = (void *) VIA2_BASE;
149 rbv_present = 0;
150 oss_present = 0;
151 rbv_clear = 0x00;
152 gIER = vIER;
153 gIFR = vIFR;
154 gBufA = vBufA;
155 gBufB = vBufB;
156 break;
157 default:
158 panic("UNKNOWN VIA TYPE");
159 }
160
161 printk(KERN_INFO "VIA1 at %p is a 6522 or clone\n", via1);
162
163 printk(KERN_INFO "VIA2 at %p is ", via2);
164 if (rbv_present) {
165 printk("an RBV\n");
166 } else if (oss_present) {
167 printk("an OSS\n");
168 } else {
169 printk("a 6522 or clone\n");
170 }
171
172 #ifdef DEBUG_VIA
173 via_debug_dump();
174 #endif
175
176 /*
177 * Shut down all IRQ sources, reset the timers, and
178 * kill the timer latch on VIA1.
179 */
180
181 via1[vIER] = 0x7F;
182 via1[vIFR] = 0x7F;
183 via1[vT1LL] = 0;
184 via1[vT1LH] = 0;
185 via1[vT1CL] = 0;
186 via1[vT1CH] = 0;
187 via1[vT2CL] = 0;
188 via1[vT2CH] = 0;
189 via1[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */
190 via1[vACR] &= ~0x03; /* disable port A & B latches */
191
192 /*
193 * SE/30: disable video IRQ
194 * XXX: testing for SE/30 VBL
195 */
196
197 if (macintosh_config->ident == MAC_MODEL_SE30) {
198 via1[vDirB] |= 0x40;
199 via1[vBufB] |= 0x40;
200 }
201
202 /*
203 * Set the RTC bits to a known state: all lines to outputs and
204 * RTC disabled (yes that's 0 to enable and 1 to disable).
205 */
206
207 via1[vDirB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk | VIA1B_vRTCData);
208 via1[vBufB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk);
209
210 /* Everything below this point is VIA2/RBV only... */
211
212 if (oss_present)
213 return;
214
215 if ((macintosh_config->via_type == MAC_VIA_QUADRA) &&
216 (macintosh_config->adb_type != MAC_ADB_PB1) &&
217 (macintosh_config->adb_type != MAC_ADB_PB2) &&
218 (macintosh_config->ident != MAC_MODEL_C660) &&
219 (macintosh_config->ident != MAC_MODEL_Q840)) {
220 via_alt_mapping = 1;
221 via1[vDirB] |= 0x40;
222 via1[vBufB] &= ~0x40;
223 } else {
224 via_alt_mapping = 0;
225 }
226
227 /*
228 * Now initialize VIA2. For RBV we just kill all interrupts;
229 * for a regular VIA we also reset the timers and stuff.
230 */
231
232 via2[gIER] = 0x7F;
233 via2[gIFR] = 0x7F | rbv_clear;
234 if (!rbv_present) {
235 via2[vT1LL] = 0;
236 via2[vT1LH] = 0;
237 via2[vT1CL] = 0;
238 via2[vT1CH] = 0;
239 via2[vT2CL] = 0;
240 via2[vT2CH] = 0;
241 via2[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */
242 via2[vACR] &= ~0x03; /* disable port A & B latches */
243 }
244
245 /* Everything below this point is VIA2 only... */
246
247 if (rbv_present)
248 return;
249
250 /*
251 * Set vPCR for control line interrupts.
252 *
253 * CA1 (SLOTS IRQ), CB1 (ASC IRQ): negative edge trigger.
254 *
255 * Macs with ESP SCSI have a negative edge triggered SCSI interrupt.
256 * Testing reveals that PowerBooks do too. However, the SE/30
257 * schematic diagram shows an active high NCR5380 IRQ line.
258 */
259
260 pr_debug("VIA2 vPCR is 0x%02X\n", via2[vPCR]);
261 if (macintosh_config->via_type == MAC_VIA_II) {
262 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, pos. edge */
263 via2[vPCR] = 0x66;
264 } else {
265 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, neg. edge */
266 via2[vPCR] = 0x22;
267 }
268 }
269
270 /*
271 * Debugging dump, used in various places to see what's going on.
272 */
273
via_debug_dump(void)274 void via_debug_dump(void)
275 {
276 printk(KERN_DEBUG "VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
277 (uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]);
278 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n",
279 (uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]);
280 if (oss_present) {
281 printk(KERN_DEBUG "VIA2: <OSS>\n");
282 } else if (rbv_present) {
283 printk(KERN_DEBUG "VIA2: IFR = 0x%02X IER = 0x%02X\n",
284 (uint) via2[rIFR], (uint) via2[rIER]);
285 printk(KERN_DEBUG " SIFR = 0x%02X SIER = 0x%02X\n",
286 (uint) via2[rSIFR], (uint) via2[rSIER]);
287 } else {
288 printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
289 (uint) via2[vDirA], (uint) via2[vDirB],
290 (uint) via2[vACR]);
291 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n",
292 (uint) via2[vPCR],
293 (uint) via2[vIFR], (uint) via2[vIER]);
294 }
295 }
296
297 /*
298 * Flush the L2 cache on Macs that have it by flipping
299 * the system into 24-bit mode for an instant.
300 */
301
via_l2_flush(int writeback)302 void via_l2_flush(int writeback)
303 {
304 unsigned long flags;
305
306 local_irq_save(flags);
307 via2[gBufB] &= ~VIA2B_vMode32;
308 via2[gBufB] |= VIA2B_vMode32;
309 local_irq_restore(flags);
310 }
311
312 /*
313 * Return the status of the L2 cache on a IIci
314 */
315
via_get_cache_disable(void)316 int via_get_cache_disable(void)
317 {
318 /* Safeguard against being called accidentally */
319 if (!via2) {
320 printk(KERN_ERR "via_get_cache_disable called on a non-VIA machine!\n");
321 return 1;
322 }
323
324 return (int) via2[gBufB] & VIA2B_vCDis;
325 }
326
327 /*
328 * Initialize VIA2 for Nubus access
329 */
330
via_nubus_init(void)331 void __init via_nubus_init(void)
332 {
333 /* unlock nubus transactions */
334
335 if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
336 (macintosh_config->adb_type != MAC_ADB_PB2)) {
337 /* set the line to be an output on non-RBV machines */
338 if (!rbv_present)
339 via2[vDirB] |= 0x02;
340
341 /* this seems to be an ADB bit on PMU machines */
342 /* according to MkLinux. -- jmt */
343 via2[gBufB] |= 0x02;
344 }
345
346 /*
347 * Disable the slot interrupts. On some hardware that's not possible.
348 * On some hardware it's unclear what all of these I/O lines do.
349 */
350
351 switch (macintosh_config->via_type) {
352 case MAC_VIA_II:
353 case MAC_VIA_QUADRA:
354 pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]);
355 break;
356 case MAC_VIA_IICI:
357 /* RBV. Disable all the slot interrupts. SIER works like IER. */
358 via2[rSIER] = 0x7F;
359 break;
360 }
361 }
362
via_nubus_irq_startup(int irq)363 void via_nubus_irq_startup(int irq)
364 {
365 int irq_idx = IRQ_IDX(irq);
366
367 switch (macintosh_config->via_type) {
368 case MAC_VIA_II:
369 case MAC_VIA_QUADRA:
370 /* Make the port A line an input. Probably redundant. */
371 if (macintosh_config->via_type == MAC_VIA_II) {
372 /* The top two bits are RAM size outputs. */
373 via2[vDirA] &= 0xC0 | ~(1 << irq_idx);
374 } else {
375 /* Allow NuBus slots 9 through F. */
376 via2[vDirA] &= 0x80 | ~(1 << irq_idx);
377 }
378 /* fall through */
379 case MAC_VIA_IICI:
380 via_irq_enable(irq);
381 break;
382 }
383 }
384
via_nubus_irq_shutdown(int irq)385 void via_nubus_irq_shutdown(int irq)
386 {
387 switch (macintosh_config->via_type) {
388 case MAC_VIA_II:
389 case MAC_VIA_QUADRA:
390 /* Ensure that the umbrella CA1 interrupt remains enabled. */
391 via_irq_enable(irq);
392 break;
393 case MAC_VIA_IICI:
394 via_irq_disable(irq);
395 break;
396 }
397 }
398
399 /*
400 * The generic VIA interrupt routines (shamelessly stolen from Alan Cox's
401 * via6522.c :-), disable/pending masks added.
402 */
403
404 #define VIA_TIMER_1_INT BIT(6)
405
via1_irq(struct irq_desc * desc)406 void via1_irq(struct irq_desc *desc)
407 {
408 int irq_num;
409 unsigned char irq_bit, events;
410
411 events = via1[vIFR] & via1[vIER] & 0x7F;
412 if (!events)
413 return;
414
415 irq_num = IRQ_MAC_TIMER_1;
416 irq_bit = VIA_TIMER_1_INT;
417 if (events & irq_bit) {
418 unsigned long flags;
419
420 local_irq_save(flags);
421 via1[vIFR] = irq_bit;
422 generic_handle_irq(irq_num);
423 local_irq_restore(flags);
424
425 events &= ~irq_bit;
426 if (!events)
427 return;
428 }
429
430 irq_num = VIA1_SOURCE_BASE;
431 irq_bit = 1;
432 do {
433 if (events & irq_bit) {
434 via1[vIFR] = irq_bit;
435 generic_handle_irq(irq_num);
436 }
437 ++irq_num;
438 irq_bit <<= 1;
439 } while (events >= irq_bit);
440 }
441
via2_irq(struct irq_desc * desc)442 static void via2_irq(struct irq_desc *desc)
443 {
444 int irq_num;
445 unsigned char irq_bit, events;
446
447 events = via2[gIFR] & via2[gIER] & 0x7F;
448 if (!events)
449 return;
450
451 irq_num = VIA2_SOURCE_BASE;
452 irq_bit = 1;
453 do {
454 if (events & irq_bit) {
455 via2[gIFR] = irq_bit | rbv_clear;
456 generic_handle_irq(irq_num);
457 }
458 ++irq_num;
459 irq_bit <<= 1;
460 } while (events >= irq_bit);
461 }
462
463 /*
464 * Dispatch Nubus interrupts. We are called as a secondary dispatch by the
465 * VIA2 dispatcher as a fast interrupt handler.
466 */
467
via_nubus_irq(struct irq_desc * desc)468 static void via_nubus_irq(struct irq_desc *desc)
469 {
470 int slot_irq;
471 unsigned char slot_bit, events;
472
473 events = ~via2[gBufA] & 0x7F;
474 if (rbv_present)
475 events &= via2[rSIER];
476 else
477 events &= ~via2[vDirA];
478 if (!events)
479 return;
480
481 do {
482 slot_irq = IRQ_NUBUS_F;
483 slot_bit = 0x40;
484 do {
485 if (events & slot_bit) {
486 events &= ~slot_bit;
487 generic_handle_irq(slot_irq);
488 }
489 --slot_irq;
490 slot_bit >>= 1;
491 } while (events);
492
493 /* clear the CA1 interrupt and make certain there's no more. */
494 via2[gIFR] = 0x02 | rbv_clear;
495 events = ~via2[gBufA] & 0x7F;
496 if (rbv_present)
497 events &= via2[rSIER];
498 else
499 events &= ~via2[vDirA];
500 } while (events);
501 }
502
503 /*
504 * Register the interrupt dispatchers for VIA or RBV machines only.
505 */
506
via_register_interrupts(void)507 void __init via_register_interrupts(void)
508 {
509 if (via_alt_mapping) {
510 /* software interrupt */
511 irq_set_chained_handler(IRQ_AUTO_1, via1_irq);
512 /* via1 interrupt */
513 irq_set_chained_handler(IRQ_AUTO_6, via1_irq);
514 } else {
515 irq_set_chained_handler(IRQ_AUTO_1, via1_irq);
516 }
517 irq_set_chained_handler(IRQ_AUTO_2, via2_irq);
518 irq_set_chained_handler(IRQ_MAC_NUBUS, via_nubus_irq);
519 }
520
via_irq_enable(int irq)521 void via_irq_enable(int irq) {
522 int irq_src = IRQ_SRC(irq);
523 int irq_idx = IRQ_IDX(irq);
524
525 #ifdef DEBUG_IRQUSE
526 printk(KERN_DEBUG "via_irq_enable(%d)\n", irq);
527 #endif
528
529 if (irq_src == 1) {
530 via1[vIER] = IER_SET_BIT(irq_idx);
531 } else if (irq_src == 2) {
532 if (irq != IRQ_MAC_NUBUS || nubus_disabled == 0)
533 via2[gIER] = IER_SET_BIT(irq_idx);
534 } else if (irq_src == 7) {
535 switch (macintosh_config->via_type) {
536 case MAC_VIA_II:
537 case MAC_VIA_QUADRA:
538 nubus_disabled &= ~(1 << irq_idx);
539 /* Enable the CA1 interrupt when no slot is disabled. */
540 if (!nubus_disabled)
541 via2[gIER] = IER_SET_BIT(1);
542 break;
543 case MAC_VIA_IICI:
544 /* On RBV, enable the slot interrupt.
545 * SIER works like IER.
546 */
547 via2[rSIER] = IER_SET_BIT(irq_idx);
548 break;
549 }
550 }
551 }
552
via_irq_disable(int irq)553 void via_irq_disable(int irq) {
554 int irq_src = IRQ_SRC(irq);
555 int irq_idx = IRQ_IDX(irq);
556
557 #ifdef DEBUG_IRQUSE
558 printk(KERN_DEBUG "via_irq_disable(%d)\n", irq);
559 #endif
560
561 if (irq_src == 1) {
562 via1[vIER] = IER_CLR_BIT(irq_idx);
563 } else if (irq_src == 2) {
564 via2[gIER] = IER_CLR_BIT(irq_idx);
565 } else if (irq_src == 7) {
566 switch (macintosh_config->via_type) {
567 case MAC_VIA_II:
568 case MAC_VIA_QUADRA:
569 nubus_disabled |= 1 << irq_idx;
570 if (nubus_disabled)
571 via2[gIER] = IER_CLR_BIT(1);
572 break;
573 case MAC_VIA_IICI:
574 via2[rSIER] = IER_CLR_BIT(irq_idx);
575 break;
576 }
577 }
578 }
579
via1_set_head(int head)580 void via1_set_head(int head)
581 {
582 if (head == 0)
583 via1[vBufA] &= ~VIA1A_vHeadSel;
584 else
585 via1[vBufA] |= VIA1A_vHeadSel;
586 }
587 EXPORT_SYMBOL(via1_set_head);
588
via2_scsi_drq_pending(void)589 int via2_scsi_drq_pending(void)
590 {
591 return via2[gIFR] & (1 << IRQ_IDX(IRQ_MAC_SCSIDRQ));
592 }
593 EXPORT_SYMBOL(via2_scsi_drq_pending);
594
595 /* timer and clock source */
596
597 #define VIA_CLOCK_FREQ 783360 /* VIA "phase 2" clock in Hz */
598 #define VIA_TIMER_INTERVAL (1000000 / HZ) /* microseconds per jiffy */
599 #define VIA_TIMER_CYCLES (VIA_CLOCK_FREQ / HZ) /* clock cycles per jiffy */
600
601 #define VIA_TC (VIA_TIMER_CYCLES - 2) /* including 0 and -1 */
602 #define VIA_TC_LOW (VIA_TC & 0xFF)
603 #define VIA_TC_HIGH (VIA_TC >> 8)
604
via_init_clock(irq_handler_t timer_routine)605 void __init via_init_clock(irq_handler_t timer_routine)
606 {
607 if (request_irq(IRQ_MAC_TIMER_1, timer_routine, 0, "timer", NULL)) {
608 pr_err("Couldn't register %s interrupt\n", "timer");
609 return;
610 }
611
612 via1[vT1LL] = VIA_TC_LOW;
613 via1[vT1LH] = VIA_TC_HIGH;
614 via1[vT1CL] = VIA_TC_LOW;
615 via1[vT1CH] = VIA_TC_HIGH;
616 via1[vACR] |= 0x40;
617 }
618
mac_gettimeoffset(void)619 u32 mac_gettimeoffset(void)
620 {
621 unsigned long flags;
622 u8 count_high;
623 u16 count, offset = 0;
624
625 /*
626 * Timer counter wrap-around is detected with the timer interrupt flag
627 * but reading the counter low byte (vT1CL) would reset the flag.
628 * Also, accessing both counter registers is essentially a data race.
629 * These problems are avoided by ignoring the low byte. Clock accuracy
630 * is 256 times worse (error can reach 0.327 ms) but CPU overhead is
631 * reduced by avoiding slow VIA register accesses.
632 */
633
634 local_irq_save(flags);
635 count_high = via1[vT1CH];
636 if (count_high == 0xFF)
637 count_high = 0;
638 if (count_high > 0 && (via1[vIFR] & VIA_TIMER_1_INT))
639 offset = VIA_TIMER_CYCLES;
640 local_irq_restore(flags);
641
642 count = count_high << 8;
643 count = VIA_TIMER_CYCLES - count + offset;
644
645 return ((count * VIA_TIMER_INTERVAL) / VIA_TIMER_CYCLES) * 1000;
646 }
647