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 * Timer defs.
58 */
59
60 #define TICK_SIZE 10000
61 #define MAC_CLOCK_TICK (783300/HZ) /* ticks per HZ */
62 #define MAC_CLOCK_LOW (MAC_CLOCK_TICK&0xFF)
63 #define MAC_CLOCK_HIGH (MAC_CLOCK_TICK>>8)
64
65
66 /*
67 * On Macs with a genuine VIA chip there is no way to mask an individual slot
68 * interrupt. This limitation also seems to apply to VIA clone logic cores in
69 * Quadra-like ASICs. (RBV and OSS machines don't have this limitation.)
70 *
71 * We used to fake it by configuring the relevent VIA pin as an output
72 * (to mask the interrupt) or input (to unmask). That scheme did not work on
73 * (at least) the Quadra 700. A NuBus card's /NMRQ signal is an open-collector
74 * circuit (see Designing Cards and Drivers for Macintosh II and Macintosh SE,
75 * p. 10-11 etc) but VIA outputs are not (see datasheet).
76 *
77 * Driving these outputs high must cause the VIA to source current and the
78 * card to sink current when it asserts /NMRQ. Current will flow but the pin
79 * voltage is uncertain and so the /NMRQ condition may still cause a transition
80 * at the VIA2 CA1 input (which explains the lost interrupts). A side effect
81 * is that a disabled slot IRQ can never be tested as pending or not.
82 *
83 * Driving these outputs low doesn't work either. All the slot /NMRQ lines are
84 * (active low) OR'd together to generate the CA1 (aka "SLOTS") interrupt (see
85 * The Guide To Macintosh Family Hardware, 2nd edition p. 167). If we drive a
86 * disabled /NMRQ line low, the falling edge immediately triggers a CA1
87 * interrupt and all slot interrupts after that will generate no transition
88 * and therefore no interrupt, even after being re-enabled.
89 *
90 * So we make the VIA port A I/O lines inputs and use nubus_disabled to keep
91 * track of their states. When any slot IRQ becomes disabled we mask the CA1
92 * umbrella interrupt. Only when all slot IRQs become enabled do we unmask
93 * the CA1 interrupt. It must remain enabled even when cards have no interrupt
94 * handler registered. Drivers must therefore disable a slot interrupt at the
95 * device before they call free_irq (like shared and autovector interrupts).
96 *
97 * There is also a related problem when MacOS is used to boot Linux. A network
98 * card brought up by a MacOS driver may raise an interrupt while Linux boots.
99 * This can be fatal since it can't be handled until the right driver loads
100 * (if such a driver exists at all). Apparently related to this hardware
101 * limitation, "Designing Cards and Drivers", p. 9-8, says that a slot
102 * interrupt with no driver would crash MacOS (the book was written before
103 * the appearance of Macs with RBV or OSS).
104 */
105
106 static u8 nubus_disabled;
107
108 void via_debug_dump(void);
109
110 /*
111 * Initialize the VIAs
112 *
113 * First we figure out where they actually _are_ as well as what type of
114 * VIA we have for VIA2 (it could be a real VIA or an RBV or even an OSS.)
115 * Then we pretty much clear them out and disable all IRQ sources.
116 *
117 * Note: the OSS is actually "detected" here and not in oss_init(). It just
118 * seems more logical to do it here since via_init() needs to know
119 * these things anyways.
120 */
121
via_init(void)122 void __init via_init(void)
123 {
124 switch(macintosh_config->via_type) {
125
126 /* IIci, IIsi, IIvx, IIvi (P6xx), LC series */
127
128 case MAC_VIA_IICI:
129 via1 = (void *) VIA1_BASE;
130 if (macintosh_config->ident == MAC_MODEL_IIFX) {
131 via2 = NULL;
132 rbv_present = 0;
133 oss_present = 1;
134 } else {
135 via2 = (void *) RBV_BASE;
136 rbv_present = 1;
137 oss_present = 0;
138 }
139 if (macintosh_config->ident == MAC_MODEL_LCIII) {
140 rbv_clear = 0x00;
141 } else {
142 /* on most RBVs (& unlike the VIAs), you */
143 /* need to set bit 7 when you write to IFR */
144 /* in order for your clear to occur. */
145 rbv_clear = 0x80;
146 }
147 gIER = rIER;
148 gIFR = rIFR;
149 gBufA = rSIFR;
150 gBufB = rBufB;
151 break;
152
153 /* Quadra and early MacIIs agree on the VIA locations */
154
155 case MAC_VIA_QUADRA:
156 case MAC_VIA_II:
157 via1 = (void *) VIA1_BASE;
158 via2 = (void *) VIA2_BASE;
159 rbv_present = 0;
160 oss_present = 0;
161 rbv_clear = 0x00;
162 gIER = vIER;
163 gIFR = vIFR;
164 gBufA = vBufA;
165 gBufB = vBufB;
166 break;
167 default:
168 panic("UNKNOWN VIA TYPE");
169 }
170
171 printk(KERN_INFO "VIA1 at %p is a 6522 or clone\n", via1);
172
173 printk(KERN_INFO "VIA2 at %p is ", via2);
174 if (rbv_present) {
175 printk("an RBV\n");
176 } else if (oss_present) {
177 printk("an OSS\n");
178 } else {
179 printk("a 6522 or clone\n");
180 }
181
182 #ifdef DEBUG_VIA
183 via_debug_dump();
184 #endif
185
186 /*
187 * Shut down all IRQ sources, reset the timers, and
188 * kill the timer latch on VIA1.
189 */
190
191 via1[vIER] = 0x7F;
192 via1[vIFR] = 0x7F;
193 via1[vT1LL] = 0;
194 via1[vT1LH] = 0;
195 via1[vT1CL] = 0;
196 via1[vT1CH] = 0;
197 via1[vT2CL] = 0;
198 via1[vT2CH] = 0;
199 via1[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */
200 via1[vACR] &= ~0x03; /* disable port A & B latches */
201
202 /*
203 * SE/30: disable video IRQ
204 * XXX: testing for SE/30 VBL
205 */
206
207 if (macintosh_config->ident == MAC_MODEL_SE30) {
208 via1[vDirB] |= 0x40;
209 via1[vBufB] |= 0x40;
210 }
211
212 /*
213 * Set the RTC bits to a known state: all lines to outputs and
214 * RTC disabled (yes that's 0 to enable and 1 to disable).
215 */
216
217 via1[vDirB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk | VIA1B_vRTCData);
218 via1[vBufB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk);
219
220 /* Everything below this point is VIA2/RBV only... */
221
222 if (oss_present)
223 return;
224
225 if ((macintosh_config->via_type == MAC_VIA_QUADRA) &&
226 (macintosh_config->adb_type != MAC_ADB_PB1) &&
227 (macintosh_config->adb_type != MAC_ADB_PB2) &&
228 (macintosh_config->ident != MAC_MODEL_C660) &&
229 (macintosh_config->ident != MAC_MODEL_Q840)) {
230 via_alt_mapping = 1;
231 via1[vDirB] |= 0x40;
232 via1[vBufB] &= ~0x40;
233 } else {
234 via_alt_mapping = 0;
235 }
236
237 /*
238 * Now initialize VIA2. For RBV we just kill all interrupts;
239 * for a regular VIA we also reset the timers and stuff.
240 */
241
242 via2[gIER] = 0x7F;
243 via2[gIFR] = 0x7F | rbv_clear;
244 if (!rbv_present) {
245 via2[vT1LL] = 0;
246 via2[vT1LH] = 0;
247 via2[vT1CL] = 0;
248 via2[vT1CH] = 0;
249 via2[vT2CL] = 0;
250 via2[vT2CH] = 0;
251 via2[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */
252 via2[vACR] &= ~0x03; /* disable port A & B latches */
253 }
254
255 /* Everything below this point is VIA2 only... */
256
257 if (rbv_present)
258 return;
259
260 /*
261 * Set vPCR for control line interrupts.
262 *
263 * CA1 (SLOTS IRQ), CB1 (ASC IRQ): negative edge trigger.
264 *
265 * Macs with ESP SCSI have a negative edge triggered SCSI interrupt.
266 * Testing reveals that PowerBooks do too. However, the SE/30
267 * schematic diagram shows an active high NCR5380 IRQ line.
268 */
269
270 pr_debug("VIA2 vPCR is 0x%02X\n", via2[vPCR]);
271 if (macintosh_config->via_type == MAC_VIA_II) {
272 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, pos. edge */
273 via2[vPCR] = 0x66;
274 } else {
275 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, neg. edge */
276 via2[vPCR] = 0x22;
277 }
278 }
279
280 /*
281 * Start the 100 Hz clock
282 */
283
via_init_clock(irq_handler_t func)284 void __init via_init_clock(irq_handler_t func)
285 {
286 via1[vACR] |= 0x40;
287 via1[vT1LL] = MAC_CLOCK_LOW;
288 via1[vT1LH] = MAC_CLOCK_HIGH;
289 via1[vT1CL] = MAC_CLOCK_LOW;
290 via1[vT1CH] = MAC_CLOCK_HIGH;
291
292 if (request_irq(IRQ_MAC_TIMER_1, func, 0, "timer", func))
293 pr_err("Couldn't register %s interrupt\n", "timer");
294 }
295
296 /*
297 * Debugging dump, used in various places to see what's going on.
298 */
299
via_debug_dump(void)300 void via_debug_dump(void)
301 {
302 printk(KERN_DEBUG "VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
303 (uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]);
304 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n",
305 (uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]);
306 if (oss_present) {
307 printk(KERN_DEBUG "VIA2: <OSS>\n");
308 } else if (rbv_present) {
309 printk(KERN_DEBUG "VIA2: IFR = 0x%02X IER = 0x%02X\n",
310 (uint) via2[rIFR], (uint) via2[rIER]);
311 printk(KERN_DEBUG " SIFR = 0x%02X SIER = 0x%02X\n",
312 (uint) via2[rSIFR], (uint) via2[rSIER]);
313 } else {
314 printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
315 (uint) via2[vDirA], (uint) via2[vDirB],
316 (uint) via2[vACR]);
317 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n",
318 (uint) via2[vPCR],
319 (uint) via2[vIFR], (uint) via2[vIER]);
320 }
321 }
322
323 /*
324 * This is always executed with interrupts disabled.
325 *
326 * TBI: get time offset between scheduling timer ticks
327 */
328
mac_gettimeoffset(void)329 u32 mac_gettimeoffset(void)
330 {
331 unsigned long ticks, offset = 0;
332
333 /* read VIA1 timer 2 current value */
334 ticks = via1[vT1CL] | (via1[vT1CH] << 8);
335 /* The probability of underflow is less than 2% */
336 if (ticks > MAC_CLOCK_TICK - MAC_CLOCK_TICK / 50)
337 /* Check for pending timer interrupt in VIA1 IFR */
338 if (via1[vIFR] & 0x40) offset = TICK_SIZE;
339
340 ticks = MAC_CLOCK_TICK - ticks;
341 ticks = ticks * 10000L / MAC_CLOCK_TICK;
342
343 return (ticks + offset) * 1000;
344 }
345
346 /*
347 * Flush the L2 cache on Macs that have it by flipping
348 * the system into 24-bit mode for an instant.
349 */
350
via_flush_cache(void)351 void via_flush_cache(void)
352 {
353 via2[gBufB] &= ~VIA2B_vMode32;
354 via2[gBufB] |= VIA2B_vMode32;
355 }
356
357 /*
358 * Return the status of the L2 cache on a IIci
359 */
360
via_get_cache_disable(void)361 int via_get_cache_disable(void)
362 {
363 /* Safeguard against being called accidentally */
364 if (!via2) {
365 printk(KERN_ERR "via_get_cache_disable called on a non-VIA machine!\n");
366 return 1;
367 }
368
369 return (int) via2[gBufB] & VIA2B_vCDis;
370 }
371
372 /*
373 * Initialize VIA2 for Nubus access
374 */
375
via_nubus_init(void)376 void __init via_nubus_init(void)
377 {
378 /* unlock nubus transactions */
379
380 if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
381 (macintosh_config->adb_type != MAC_ADB_PB2)) {
382 /* set the line to be an output on non-RBV machines */
383 if (!rbv_present)
384 via2[vDirB] |= 0x02;
385
386 /* this seems to be an ADB bit on PMU machines */
387 /* according to MkLinux. -- jmt */
388 via2[gBufB] |= 0x02;
389 }
390
391 /*
392 * Disable the slot interrupts. On some hardware that's not possible.
393 * On some hardware it's unclear what all of these I/O lines do.
394 */
395
396 switch (macintosh_config->via_type) {
397 case MAC_VIA_II:
398 case MAC_VIA_QUADRA:
399 pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]);
400 break;
401 case MAC_VIA_IICI:
402 /* RBV. Disable all the slot interrupts. SIER works like IER. */
403 via2[rSIER] = 0x7F;
404 break;
405 }
406 }
407
via_nubus_irq_startup(int irq)408 void via_nubus_irq_startup(int irq)
409 {
410 int irq_idx = IRQ_IDX(irq);
411
412 switch (macintosh_config->via_type) {
413 case MAC_VIA_II:
414 case MAC_VIA_QUADRA:
415 /* Make the port A line an input. Probably redundant. */
416 if (macintosh_config->via_type == MAC_VIA_II) {
417 /* The top two bits are RAM size outputs. */
418 via2[vDirA] &= 0xC0 | ~(1 << irq_idx);
419 } else {
420 /* Allow NuBus slots 9 through F. */
421 via2[vDirA] &= 0x80 | ~(1 << irq_idx);
422 }
423 /* fall through */
424 case MAC_VIA_IICI:
425 via_irq_enable(irq);
426 break;
427 }
428 }
429
via_nubus_irq_shutdown(int irq)430 void via_nubus_irq_shutdown(int irq)
431 {
432 switch (macintosh_config->via_type) {
433 case MAC_VIA_II:
434 case MAC_VIA_QUADRA:
435 /* Ensure that the umbrella CA1 interrupt remains enabled. */
436 via_irq_enable(irq);
437 break;
438 case MAC_VIA_IICI:
439 via_irq_disable(irq);
440 break;
441 }
442 }
443
444 /*
445 * The generic VIA interrupt routines (shamelessly stolen from Alan Cox's
446 * via6522.c :-), disable/pending masks added.
447 */
448
via1_irq(unsigned int irq,struct irq_desc * desc)449 void via1_irq(unsigned int irq, struct irq_desc *desc)
450 {
451 int irq_num;
452 unsigned char irq_bit, events;
453
454 events = via1[vIFR] & via1[vIER] & 0x7F;
455 if (!events)
456 return;
457
458 irq_num = VIA1_SOURCE_BASE;
459 irq_bit = 1;
460 do {
461 if (events & irq_bit) {
462 via1[vIFR] = irq_bit;
463 generic_handle_irq(irq_num);
464 }
465 ++irq_num;
466 irq_bit <<= 1;
467 } while (events >= irq_bit);
468 }
469
via2_irq(unsigned int irq,struct irq_desc * desc)470 static void via2_irq(unsigned int irq, struct irq_desc *desc)
471 {
472 int irq_num;
473 unsigned char irq_bit, events;
474
475 events = via2[gIFR] & via2[gIER] & 0x7F;
476 if (!events)
477 return;
478
479 irq_num = VIA2_SOURCE_BASE;
480 irq_bit = 1;
481 do {
482 if (events & irq_bit) {
483 via2[gIFR] = irq_bit | rbv_clear;
484 generic_handle_irq(irq_num);
485 }
486 ++irq_num;
487 irq_bit <<= 1;
488 } while (events >= irq_bit);
489 }
490
491 /*
492 * Dispatch Nubus interrupts. We are called as a secondary dispatch by the
493 * VIA2 dispatcher as a fast interrupt handler.
494 */
495
via_nubus_irq(unsigned int irq,struct irq_desc * desc)496 void via_nubus_irq(unsigned int irq, struct irq_desc *desc)
497 {
498 int slot_irq;
499 unsigned char slot_bit, events;
500
501 events = ~via2[gBufA] & 0x7F;
502 if (rbv_present)
503 events &= via2[rSIER];
504 else
505 events &= ~via2[vDirA];
506 if (!events)
507 return;
508
509 do {
510 slot_irq = IRQ_NUBUS_F;
511 slot_bit = 0x40;
512 do {
513 if (events & slot_bit) {
514 events &= ~slot_bit;
515 generic_handle_irq(slot_irq);
516 }
517 --slot_irq;
518 slot_bit >>= 1;
519 } while (events);
520
521 /* clear the CA1 interrupt and make certain there's no more. */
522 via2[gIFR] = 0x02 | rbv_clear;
523 events = ~via2[gBufA] & 0x7F;
524 if (rbv_present)
525 events &= via2[rSIER];
526 else
527 events &= ~via2[vDirA];
528 } while (events);
529 }
530
531 /*
532 * Register the interrupt dispatchers for VIA or RBV machines only.
533 */
534
via_register_interrupts(void)535 void __init via_register_interrupts(void)
536 {
537 if (via_alt_mapping) {
538 /* software interrupt */
539 irq_set_chained_handler(IRQ_AUTO_1, via1_irq);
540 /* via1 interrupt */
541 irq_set_chained_handler(IRQ_AUTO_6, via1_irq);
542 } else {
543 irq_set_chained_handler(IRQ_AUTO_1, via1_irq);
544 }
545 irq_set_chained_handler(IRQ_AUTO_2, via2_irq);
546 irq_set_chained_handler(IRQ_MAC_NUBUS, via_nubus_irq);
547 }
548
via_irq_enable(int irq)549 void via_irq_enable(int irq) {
550 int irq_src = IRQ_SRC(irq);
551 int irq_idx = IRQ_IDX(irq);
552
553 #ifdef DEBUG_IRQUSE
554 printk(KERN_DEBUG "via_irq_enable(%d)\n", irq);
555 #endif
556
557 if (irq_src == 1) {
558 via1[vIER] = IER_SET_BIT(irq_idx);
559 } else if (irq_src == 2) {
560 if (irq != IRQ_MAC_NUBUS || nubus_disabled == 0)
561 via2[gIER] = IER_SET_BIT(irq_idx);
562 } else if (irq_src == 7) {
563 switch (macintosh_config->via_type) {
564 case MAC_VIA_II:
565 case MAC_VIA_QUADRA:
566 nubus_disabled &= ~(1 << irq_idx);
567 /* Enable the CA1 interrupt when no slot is disabled. */
568 if (!nubus_disabled)
569 via2[gIER] = IER_SET_BIT(1);
570 break;
571 case MAC_VIA_IICI:
572 /* On RBV, enable the slot interrupt.
573 * SIER works like IER.
574 */
575 via2[rSIER] = IER_SET_BIT(irq_idx);
576 break;
577 }
578 }
579 }
580
via_irq_disable(int irq)581 void via_irq_disable(int irq) {
582 int irq_src = IRQ_SRC(irq);
583 int irq_idx = IRQ_IDX(irq);
584
585 #ifdef DEBUG_IRQUSE
586 printk(KERN_DEBUG "via_irq_disable(%d)\n", irq);
587 #endif
588
589 if (irq_src == 1) {
590 via1[vIER] = IER_CLR_BIT(irq_idx);
591 } else if (irq_src == 2) {
592 via2[gIER] = IER_CLR_BIT(irq_idx);
593 } else if (irq_src == 7) {
594 switch (macintosh_config->via_type) {
595 case MAC_VIA_II:
596 case MAC_VIA_QUADRA:
597 nubus_disabled |= 1 << irq_idx;
598 if (nubus_disabled)
599 via2[gIER] = IER_CLR_BIT(1);
600 break;
601 case MAC_VIA_IICI:
602 via2[rSIER] = IER_CLR_BIT(irq_idx);
603 break;
604 }
605 }
606 }
607
via1_set_head(int head)608 void via1_set_head(int head)
609 {
610 if (head == 0)
611 via1[vBufA] &= ~VIA1A_vHeadSel;
612 else
613 via1[vBufA] |= VIA1A_vHeadSel;
614 }
615 EXPORT_SYMBOL(via1_set_head);
616
via2_scsi_drq_pending(void)617 int via2_scsi_drq_pending(void)
618 {
619 return via2[gIFR] & (1 << IRQ_IDX(IRQ_MAC_SCSIDRQ));
620 }
621 EXPORT_SYMBOL(via2_scsi_drq_pending);
622