2 * 6522 Versatile Interface Adapter (VIA)
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.
7 * CSA: Motorola seems to have removed documentation on the 6522 from
9 * http://nerini.drf.com/vectrex/other/text/chips/6522/
10 * http://www.zymurgy.net/classic/vic20/vicdet1.htm
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
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
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)
25 #include <linux/types.h>
26 #include <linux/kernel.h>
28 #include <linux/delay.h>
29 #include <linux/init.h>
30 #include <linux/module.h>
31 #include <linux/irq.h>
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>
40 volatile __u8 *via1, *via2;
43 EXPORT_SYMBOL(via_alt_mapping);
44 static __u8 rbv_clear;
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)
55 static int gIER,gIFR,gBufA,gBufB;
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)
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.)
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).
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.
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.
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).
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).
107 static u8 nubus_disabled;
109 void via_debug_dump(void);
112 * Initialize the VIAs
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.
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.
123 void __init via_init(void)
125 switch(macintosh_config->via_type) {
127 /* IIci, IIsi, IIvx, IIvi (P6xx), LC series */
130 via1 = (void *) VIA1_BASE;
131 if (macintosh_config->ident == MAC_MODEL_IIFX) {
136 via2 = (void *) RBV_BASE;
140 if (macintosh_config->ident == MAC_MODEL_LCIII) {
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. */
154 /* Quadra and early MacIIs agree on the VIA locations */
158 via1 = (void *) VIA1_BASE;
159 via2 = (void *) VIA2_BASE;
169 panic("UNKNOWN VIA TYPE");
172 printk(KERN_INFO "VIA1 at %p is a 6522 or clone\n", via1);
174 printk(KERN_INFO "VIA2 at %p is ", via2);
177 } else if (oss_present) {
180 printk("a 6522 or clone\n");
188 * Shut down all IRQ sources, reset the timers, and
189 * kill the timer latch on VIA1.
200 via1[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */
201 via1[vACR] &= ~0x03; /* disable port A & B latches */
204 * SE/30: disable video IRQ
205 * XXX: testing for SE/30 VBL
208 if (macintosh_config->ident == MAC_MODEL_SE30) {
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).
218 via1[vDirB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk | VIA1B_vRTCData);
219 via1[vBufB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk);
221 /* Everything below this point is VIA2/RBV only... */
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)) {
233 via1[vBufB] &= ~0x40;
239 * Now initialize VIA2. For RBV we just kill all interrupts;
240 * for a regular VIA we also reset the timers and stuff.
244 via2[gIFR] = 0x7F | rbv_clear;
252 via2[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */
253 via2[vACR] &= ~0x03; /* disable port A & B latches */
256 /* Everything below this point is VIA2 only... */
262 * Set vPCR for control line interrupts.
264 * CA1 (SLOTS IRQ), CB1 (ASC IRQ): negative edge trigger.
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.
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 */
276 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, neg. edge */
282 * Start the 100 Hz clock
285 void __init via_init_clock(irq_handler_t func)
288 via1[vT1LL] = MAC_CLOCK_LOW;
289 via1[vT1LH] = MAC_CLOCK_HIGH;
290 via1[vT1CL] = MAC_CLOCK_LOW;
291 via1[vT1CH] = MAC_CLOCK_HIGH;
293 if (request_irq(IRQ_MAC_TIMER_1, func, 0, "timer", func))
294 pr_err("Couldn't register %s interrupt\n", "timer");
298 * Debugging dump, used in various places to see what's going on.
301 void via_debug_dump(void)
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]);
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]);
315 printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
316 (uint) via2[vDirA], (uint) via2[vDirB],
318 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n",
320 (uint) via2[vIFR], (uint) via2[vIER]);
325 * This is always executed with interrupts disabled.
327 * TBI: get time offset between scheduling timer ticks
330 u32 mac_gettimeoffset(void)
332 unsigned long ticks, offset = 0;
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;
341 ticks = MAC_CLOCK_TICK - ticks;
342 ticks = ticks * 10000L / MAC_CLOCK_TICK;
344 return (ticks + offset) * 1000;
348 * Flush the L2 cache on Macs that have it by flipping
349 * the system into 24-bit mode for an instant.
352 void via_flush_cache(void)
354 via2[gBufB] &= ~VIA2B_vMode32;
355 via2[gBufB] |= VIA2B_vMode32;
359 * Return the status of the L2 cache on a IIci
362 int via_get_cache_disable(void)
364 /* Safeguard against being called accidentally */
366 printk(KERN_ERR "via_get_cache_disable called on a non-VIA machine!\n");
370 return (int) via2[gBufB] & VIA2B_vCDis;
374 * Initialize VIA2 for Nubus access
377 void __init via_nubus_init(void)
379 /* unlock nubus transactions */
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 */
387 /* this seems to be an ADB bit on PMU machines */
388 /* according to MkLinux. -- jmt */
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.
397 switch (macintosh_config->via_type) {
400 pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]);
403 /* RBV. Disable all the slot interrupts. SIER works like IER. */
409 void via_nubus_irq_startup(int irq)
411 int irq_idx = IRQ_IDX(irq);
413 switch (macintosh_config->via_type) {
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);
421 /* Allow NuBus slots 9 through F. */
422 via2[vDirA] &= 0x80 | ~(1 << irq_idx);
431 void via_nubus_irq_shutdown(int irq)
433 switch (macintosh_config->via_type) {
436 /* Ensure that the umbrella CA1 interrupt remains enabled. */
440 via_irq_disable(irq);
446 * The generic VIA interrupt routines (shamelessly stolen from Alan Cox's
447 * via6522.c :-), disable/pending masks added.
450 void via1_irq(unsigned int irq, struct irq_desc *desc)
453 unsigned char irq_bit, events;
455 events = via1[vIFR] & via1[vIER] & 0x7F;
459 irq_num = VIA1_SOURCE_BASE;
462 if (events & irq_bit) {
463 via1[vIFR] = irq_bit;
464 generic_handle_irq(irq_num);
468 } while (events >= irq_bit);
471 static void via2_irq(unsigned int irq, struct irq_desc *desc)
474 unsigned char irq_bit, events;
476 events = via2[gIFR] & via2[gIER] & 0x7F;
480 irq_num = VIA2_SOURCE_BASE;
483 if (events & irq_bit) {
484 via2[gIFR] = irq_bit | rbv_clear;
485 generic_handle_irq(irq_num);
489 } while (events >= irq_bit);
493 * Dispatch Nubus interrupts. We are called as a secondary dispatch by the
494 * VIA2 dispatcher as a fast interrupt handler.
497 void via_nubus_irq(unsigned int irq, struct irq_desc *desc)
500 unsigned char slot_bit, events;
502 events = ~via2[gBufA] & 0x7F;
504 events &= via2[rSIER];
506 events &= ~via2[vDirA];
511 slot_irq = IRQ_NUBUS_F;
514 if (events & slot_bit) {
516 generic_handle_irq(slot_irq);
522 /* clear the CA1 interrupt and make certain there's no more. */
523 via2[gIFR] = 0x02 | rbv_clear;
524 events = ~via2[gBufA] & 0x7F;
526 events &= via2[rSIER];
528 events &= ~via2[vDirA];
533 * Register the interrupt dispatchers for VIA or RBV machines only.
536 void __init via_register_interrupts(void)
538 if (via_alt_mapping) {
539 /* software interrupt */
540 irq_set_chained_handler(IRQ_AUTO_1, via1_irq);
542 irq_set_chained_handler(IRQ_AUTO_6, via1_irq);
544 irq_set_chained_handler(IRQ_AUTO_1, via1_irq);
546 irq_set_chained_handler(IRQ_AUTO_2, via2_irq);
547 irq_set_chained_handler(IRQ_MAC_NUBUS, via_nubus_irq);
550 void via_irq_enable(int irq) {
551 int irq_src = IRQ_SRC(irq);
552 int irq_idx = IRQ_IDX(irq);
555 printk(KERN_DEBUG "via_irq_enable(%d)\n", irq);
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) {
567 nubus_disabled &= ~(1 << irq_idx);
568 /* Enable the CA1 interrupt when no slot is disabled. */
570 via2[gIER] = IER_SET_BIT(1);
573 /* On RBV, enable the slot interrupt.
574 * SIER works like IER.
576 via2[rSIER] = IER_SET_BIT(irq_idx);
582 void via_irq_disable(int irq) {
583 int irq_src = IRQ_SRC(irq);
584 int irq_idx = IRQ_IDX(irq);
587 printk(KERN_DEBUG "via_irq_disable(%d)\n", irq);
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) {
598 nubus_disabled |= 1 << irq_idx;
600 via2[gIER] = IER_CLR_BIT(1);
603 via2[rSIER] = IER_CLR_BIT(irq_idx);
609 void via1_set_head(int head)
612 via1[vBufA] &= ~VIA1A_vHeadSel;
614 via1[vBufA] |= VIA1A_vHeadSel;
616 EXPORT_SYMBOL(via1_set_head);
618 int via2_scsi_drq_pending(void)
620 return via2[gIFR] & (1 << IRQ_IDX(IRQ_MAC_SCSIDRQ));
622 EXPORT_SYMBOL(via2_scsi_drq_pending);