isa.c revision 1.28.2.3 1 /*-
2 * Copyright (c) 1991 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * William Jolitz.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * from: @(#)isa.c 7.2 (Berkeley) 5/13/91
37 * $Id: isa.c,v 1.28.2.3 1993/09/30 20:21:17 mycroft Exp $
38 */
39
40 /*
41 * code to manage AT bus
42 *
43 * 92/08/18 Frank P. MacLachlan (fpm (at) crash.cts.com):
44 * Fixed uninitialized variable problem and added code to deal
45 * with DMA page boundaries in isa_dmarangecheck(). Fixed word
46 * mode DMA count compution and reorganized DMA setup code in
47 * isa_dmastart()
48 */
49
50 #include "param.h"
51 #include "systm.h"
52 #include "conf.h"
53 #include "file.h"
54 #include "buf.h"
55 #include "uio.h"
56 #include "syslog.h"
57 #include "malloc.h"
58 #include "machine/cpu.h"
59 #include "machine/cpufunc.h"
60 #include "sys/device.h"
61 #include "vm/vm.h"
62 #include "i386/isa/isa.h"
63 #include "i386/isa/isavar.h"
64 #include "i386/isa/icu.h"
65 #include "i386/isa/ic/i8237.h"
66 #include "i386/isa/ic/i8042.h"
67 #include "i386/isa/timerreg.h"
68 #include "i386/isa/spkr_reg.h"
69
70 /*
71 ** Register definitions for DMA controller 1 (channels 0..3):
72 */
73 #define DMA1_CHN(c) (IO_DMA1 + 1*(2*(c))) /* addr reg for channel c */
74 #define DMA1_SMSK (IO_DMA1 + 1*10) /* single mask register */
75 #define DMA1_MODE (IO_DMA1 + 1*11) /* mode register */
76 #define DMA1_FFC (IO_DMA1 + 1*12) /* clear first/last FF */
77
78 /*
79 ** Register definitions for DMA controller 2 (channels 4..7):
80 */
81 #define DMA2_CHN(c) (IO_DMA1 + 2*(2*(c))) /* addr reg for channel c */
82 #define DMA2_SMSK (IO_DMA2 + 2*10) /* single mask register */
83 #define DMA2_MODE (IO_DMA2 + 2*11) /* mode register */
84 #define DMA2_FFC (IO_DMA2 + 2*12) /* clear first/last FF */
85
86 isa_type isa_bustype; /* type of bus */
87
88 static int isaprobe __P((struct device *, struct cfdata *, void *));
89 static void isaattach __P((struct device *, struct device *, void *));
90 static int isasubmatch __P((struct device *, struct cfdata *, void *));
91
92 struct cfdriver isacd =
93 { NULL, "isa", isaprobe, isaattach, DV_DULL, sizeof(struct isa_softc) };
94
95 void isa_defaultirq __P((void));
96 static int isaprint __P((void *, char *));
97
98 /*
99 * We think there might be an ISA bus here. Check it out.
100 */
101 static int
102 isaprobe(parent, cf, aux)
103 struct device *parent;
104 struct cfdata *cf;
105 void *aux;
106 {
107
108 /* XXX should do a real probe */
109 isa_bustype = BUS_ISA;
110 return 1;
111 }
112
113 /*
114 * Probe succeeded, someone called config_attach. Now we have to
115 * probe the ISA bus itself in our turn.
116 */
117 static void
118 isaattach(parent, self, aux)
119 struct device *parent, *self;
120 void *aux;
121 {
122
123 /* should print ISA/EISA & bus clock frequency and anything else
124 we can figure out? */
125 printf("\n");
126
127 isa_defaultirq();
128
129 enable_intr();
130 splhigh();
131 intr_enable(IRQ_SLAVE);
132
133 /* Iterate ``isasubmatch'' over all devices configured here. */
134 (void)config_search(isasubmatch, self, (void *)NULL);
135
136 /* and the problem is... if netmask == 0, then the loopback
137 * code can do some really ugly things.
138 * workaround for this: if netmask == 0, set it to 0x8000, which
139 * is the value used by splsoftclock. this is nasty, but it
140 * should work until this interrupt system goes away. -- cgd
141 */
142 if (netmask == 0)
143 netmask = 0x8000; /* same as for softclock. XXXX */
144
145 printf("biomask %x ttymask %x netmask %x impmask %x\n",
146 biomask, ttymask, netmask, impmask);
147 splnone();
148 }
149
150 /*
151 * isaattach (above) iterates this function over all the sub-devices that
152 * were configured at the ``isa'' device. Our job is to provide defaults
153 * and do some internal/external representation conversion (some of which
154 * is scheduled to get cleaned up later), then call the device's probe
155 * function. If this says the device is there, we try to reserve ISA
156 * bus memory and ports for the device, and attach it.
157 *
158 * Note that we always return 0, but our ultimate caller (isaattach)
159 * does not care that we never `match' anything. (In fact, our return
160 * value is entirely irrelevant; this function is run entirely for its
161 * side effects.)
162 */
163 static int
164 isasubmatch(isa, cf, aux)
165 struct device *isa;
166 struct cfdata *cf;
167 void *aux;
168 {
169 struct isa_attach_args ia;
170
171 #ifdef DIAGNOSTIC
172 if (cf->cf_driver->cd_match == NULL) {
173 /* we really ought to add printf formats to panic(). */
174 printf("isasubmatch: no match function for `%s' device\n",
175 cf->cf_driver->cd_name);
176 panic("isasubmatch: no match function\n");
177 }
178 #endif
179
180 /* Init the info needed in the device probe routine. */
181 ia.ia_iobase = cf->cf_iobase;
182 ia.ia_iosize = cf->cf_iosize;
183 if (cf->cf_irq == -1)
184 ia.ia_irq = IRQUNK;
185 else
186 ia.ia_irq = 1 << cf->cf_irq;
187 ia.ia_drq = cf->cf_drq;
188 ia.ia_maddr = (caddr_t)cf->cf_maddr;
189 ia.ia_msize = cf->cf_msize;
190
191 /* If driver says it's not there, believe it. */
192 if (!cf->cf_driver->cd_match(isa, cf, &ia))
193 return 0;
194
195 /* Driver says it is there. Try to reserve ports and memory. */
196 if (isa_reserveports(ia.ia_iobase, ia.ia_iosize)) {
197 if (isa_reservemem(ia.ia_maddr, ia.ia_msize))
198 config_attach(isa, cf, &ia, isaprint); /* victory! */
199 else
200 isa_unreserveports(ia.ia_iobase, ia.ia_iosize);
201 }
202
203 /* In any case, move on to next config entry. */
204 return 0;
205 }
206
207 /*
208 * Called indirectly via config_attach (see above). Config has already
209 * printed, e.g., "wdc0 at isa0". We can ignore our ``isaname'' arg
210 * (it is always NULL, by definition) and just extend the line with
211 * the standard info (port(s), irq, drq, and iomem).
212 */
213 static int
214 isaprint(aux, isaname)
215 void *aux;
216 char *isaname;
217 {
218 struct isa_attach_args *ia = aux;
219
220 if (ia->ia_iosize)
221 printf(" port 0x%x", ia->ia_iobase);
222 if (ia->ia_iosize > 1)
223 printf("-0x%x", ia->ia_iobase + ia->ia_iosize - 1);
224 #ifdef DIAGNOSTIC
225 if (ia->ia_irq == IRQUNK)
226 printf(" XXX");
227 else
228 #endif
229 if (ia->ia_irq != IRQNONE)
230 printf(" irq %d", ffs(ia->ia_irq) - 1);
231 if (ia->ia_drq != DRQUNK)
232 printf(" drq %d", ia->ia_drq);
233 if (ia->ia_msize)
234 printf(" iomem 0x%x", ia->ia_maddr);
235 if (ia->ia_msize > 1)
236 printf("-0x%x", ia->ia_maddr + ia->ia_msize - 1);
237 /* XXXX need to print flags */
238 return QUIET; /* actually, our return value is irrelevant. */
239 }
240
241
242 #define IDTVEC(name) __CONCAT(X,name)
243 /* default interrupt vector table entries */
244 extern IDTVEC(intr0), IDTVEC(intr1), IDTVEC(intr2), IDTVEC(intr3),
245 IDTVEC(intr4), IDTVEC(intr5), IDTVEC(intr6), IDTVEC(intr7),
246 IDTVEC(intr8), IDTVEC(intr9), IDTVEC(intr10), IDTVEC(intr11),
247 IDTVEC(intr12), IDTVEC(intr13), IDTVEC(intr14), IDTVEC(intr15);
248
249 static *defvec[16] = {
250 &IDTVEC(intr0), &IDTVEC(intr1), &IDTVEC(intr2), &IDTVEC(intr3),
251 &IDTVEC(intr4), &IDTVEC(intr5), &IDTVEC(intr6), &IDTVEC(intr7),
252 &IDTVEC(intr8), &IDTVEC(intr9), &IDTVEC(intr10), &IDTVEC(intr11),
253 &IDTVEC(intr12), &IDTVEC(intr13), &IDTVEC(intr14), &IDTVEC(intr15) };
254
255 /* out of range default interrupt vector gate entry */
256 extern IDTVEC(intrdefault);
257
258 /*
259 * Fill in default interrupt table, and mask all interrupts.
260 */
261 void
262 isa_defaultirq()
263 {
264 int i;
265
266 /* icu vectors */
267 for (i = ICU_OFFSET; i < ICU_OFFSET + ICU_LEN ; i++)
268 setidt(i, defvec[i], SDT_SYS386IGT, SEL_KPL);
269
270 /* out of range vectors */
271 for (; i < NIDT; i++)
272 setidt(i, &IDTVEC(intrdefault), SDT_SYS386IGT, SEL_KPL);
273
274 /* initialize 8259's */
275 outb(IO_ICU1, 0x11); /* reset; program device, four bytes */
276 outb(IO_ICU1+1, ICU_OFFSET); /* starting at this vector index */
277 outb(IO_ICU1+1, IRQ_SLAVE);
278 #ifdef AUTO_EOI_1
279 outb(IO_ICU1+1, 2 | 1); /* auto EOI, 8086 mode */
280 #else
281 outb(IO_ICU1+1, 1); /* 8086 mode */
282 #endif
283 outb(IO_ICU1+1, 0xff); /* leave interrupts masked */
284 outb(IO_ICU1, 0x0a); /* default to IRR on read */
285 #ifdef REORDER_IRQ
286 outb(IO_ICU1, 0xc0 | (3 - 1)); /* pri order 3-7, 0-2 (com2 first) */
287 #endif
288
289 outb(IO_ICU2, 0x11); /* reset; program device, four bytes */
290 outb(IO_ICU2+1, ICU_OFFSET+8); /* staring at this vector index */
291 outb(IO_ICU2+1, ffs(IRQ_SLAVE)-1);
292 #ifdef AUTO_EOI_2
293 outb(IO_ICU2+1, 2 | 1); /* auto EOI, 8086 mode */
294 #else
295 outb(IO_ICU2+1, 1); /* 8086 mode */
296 #endif
297 outb(IO_ICU2+1, 0xff); /* leave interrupts masked */
298 outb(IO_ICU2, 0x0a); /* default to IRR on read */
299 }
300
301
302 /* XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
303
304 int
305 config_isadev(isdp, mp)
306 struct isa_device *isdp;
307 u_int *mp;
308 {
309 if (isdp->id_irq) {
310 int intrno;
311
312 intrno = ffs(isdp->id_irq)-1;
313 setidt(ICU_OFFSET+intrno, isdp->id_intr,
314 SDT_SYS386IGT, SEL_KPL);
315 if(mp)
316 INTRMASK(*mp,isdp->id_irq);
317 INTREN(isdp->id_irq);
318 }
319 }
320
321
322 /* region of physical memory known to be contiguous */
323 vm_offset_t isaphysmem;
324 static caddr_t bouncebuf[8]; /* XXX */
325 static caddr_t bounced[8]; /* XXX */
326 static vm_size_t bouncesize[8]; /* XXX */
327 #define MAXDMASZ 512 /* XXX */
328
329 /* high byte of address is stored in this port for i-th dma channel */
330 static short dmapageport[8] =
331 { 0x87, 0x83, 0x81, 0x82, 0x8f, 0x8b, 0x89, 0x8a };
332
333 /*
334 * isa_dmacascade(): program 8237 DMA controller channel to accept
335 * external dma control by a board.
336 */
337 void
338 at_dma_cascade(chan)
339 unsigned chan;
340 {
341 #ifdef DEBUG
342 if (chan > 7)
343 panic("at_dma_cascade: impossible request");
344 #endif
345
346 /* set dma channel mode, and set dma channel mode */
347 if ((chan & 4) == 0) {
348 outb(DMA1_MODE, DMA37MD_CASCADE | chan);
349 outb(DMA1_SMSK, chan);
350 } else {
351 outb(DMA2_MODE, DMA37MD_CASCADE | (chan & 3));
352 outb(DMA2_SMSK, chan & 3);
353 }
354 }
355
356 /*
357 * at_dma(): program 8237 DMA controller channel, avoid page alignment
358 * problems by using a bounce buffer.
359 */
360 void
361 at_dma(flags, addr, nbytes, chan)
362 int read;
363 caddr_t addr;
364 vm_size_t nbytes;
365 unsigned chan;
366 {
367 vm_offset_t phys;
368 int waport;
369 caddr_t newaddr;
370
371 ppp if ( chan > 7
372 || (chan < 4 && nbytes > (1<<16))
373 || (chan >= 4 && (nbytes > (1<<17) || (u_int)addr & 1)))
374 panic("isa_dmastart: impossible request");
375
376 if (at_dma_rangecheck(addr, nbytes, chan)) {
377 panic("bounce buffers don't work yet\n");
378 /* XXX totally braindead; NBPG is not enough */
379 if (bouncebuf[chan] == 0)
380 bouncebuf[chan] =
381 /*(caddr_t)malloc(MAXDMASZ, M_TEMP, M_WAITOK);*/
382 (caddr_t) isaphysmem + NBPG*chan;
383 bouncesize[chan] = nbytes;
384 newaddr = bouncebuf[chan];
385 /* copy bounce buffer on write */
386 if (!read)
387 bcopy(addr, newaddr, nbytes);
388 else
389 bounced[chan] = addr;
390 addr = newaddr;
391 }
392
393 /* translate to physical */
394 phys = pmap_extract(pmap_kernel(), (vm_offset_t)addr);
395
396 if ((chan & 4) == 0) {
397 /*
398 * Program one of DMA channels 0..3. These are
399 * byte mode channels.
400 */
401 /* set dma channel mode, and reset address ff */
402 if (read)
403 outb(DMA1_MODE, DMA37MD_SINGLE|DMA37MD_WRITE|chan);
404 else
405 outb(DMA1_MODE, DMA37MD_SINGLE|DMA37MD_READ|chan);
406 outb(DMA1_FFC, 0);
407
408 /* send start address */
409 waport = DMA1_CHN(chan);
410 outb(waport, phys);
411 outb(waport, phys>>8);
412 outb(dmapageport[chan], phys>>16);
413
414 /* send count */
415 outb(waport + 1, --nbytes);
416 outb(waport + 1, nbytes>>8);
417
418 /* unmask channel */
419 outb(DMA1_SMSK, chan);
420 } else {
421 /*
422 * Program one of DMA channels 4..7. These are
423 * word mode channels.
424 */
425 /* set dma channel mode, and reset address ff */
426 if (read)
427 outb(DMA2_MODE, DMA37MD_SINGLE|DMA37MD_WRITE|(chan&3));
428 else
429 outb(DMA2_MODE, DMA37MD_SINGLE|DMA37MD_READ|(chan&3));
430 outb(DMA2_FFC, 0);
431
432 /* send start address */
433 waport = DMA2_CHN(chan - 4);
434 outb(waport, phys>>1);
435 outb(waport, phys>>9);
436 outb(dmapageport[chan], phys>>16);
437
438 /* send count */
439 nbytes >>= 1;
440 outb(waport + 2, --nbytes);
441 outb(waport + 2, nbytes>>8);
442
443 /* unmask channel */
444 outb(DMA2_SMSK, chan & 3);
445 }
446 }
447
448 void
449 at_dma_terminate(int flags, caddr_t addr, int nbytes, int chan)
450 {
451
452 if (bounced[chan]) {
453 bcopy(bouncebuf[chan], bounced[chan], bouncesize[chan]);
454 bounced[chan] = 0;
455 }
456 }
457
458 /*
459 * Check for problems with the address range of a DMA transfer
460 * (non-contiguous physical pages, outside of bus address space,
461 * crossing DMA page boundaries).
462 * Return true if special handling needed.
463 */
464
465 int
466 at_dma_rangecheck(caddr_t va, unsigned length, unsigned chan) {
467 vm_offset_t phys, priorpage = 0, endva;
468 u_int dma_pgmsk = (chan & 4) ? ~(128*1024-1) : ~(64*1024-1);
469
470 endva = (vm_offset_t)round_page(va + length);
471 for (; va < (caddr_t) endva ; va += NBPG) {
472 phys = trunc_page(pmap_extract(pmap_kernel(), (vm_offset_t)va));
473 if (phys == 0)
474 panic("isa_dmacheck: no physical page present");
475 if (phys > physmem)
476 return (1);
477 if (priorpage) {
478 if (priorpage + NBPG != phys)
479 return (1);
480 /* check if crossing a DMA page boundary */
481 if (((u_int)priorpage ^ (u_int)phys) & dma_pgmsk)
482 return (1);
483 }
484 priorpage = phys;
485 }
486 return (0);
487 }
488
489 /* head of queue waiting for physmem to become available */
490 struct buf isa_physmemq;
491
492 /* blocked waiting for resource to become free for exclusive use */
493 static isaphysmemflag;
494 /* if waited for and call requested when free (B_CALL) */
495 static void (*isaphysmemunblock)(); /* XXX needs to be a list */
496
497 /*
498 * Allocate contiguous physical memory for transfer, returning
499 * a *virtual* address to region. May block waiting for resource.
500 * (assumed to be called at splbio())
501 */
502 caddr_t
503 isa_allocphysmem(caddr_t va, unsigned length, void (*func)()) {
504
505 isaphysmemunblock = func;
506 while (isaphysmemflag & B_BUSY) {
507 isaphysmemflag |= B_WANTED;
508 sleep((caddr_t)&isaphysmemflag, PRIBIO);
509 }
510 isaphysmemflag |= B_BUSY;
511
512 return((caddr_t)isaphysmem);
513 }
514
515 /*
516 * Free contiguous physical memory used for transfer.
517 * (assumed to be called at splbio())
518 */
519 void
520 isa_freephysmem(caddr_t va, unsigned length) {
521
522 isaphysmemflag &= ~B_BUSY;
523 if (isaphysmemflag & B_WANTED) {
524 isaphysmemflag &= B_WANTED;
525 wakeup((caddr_t)&isaphysmemflag);
526 if (isaphysmemunblock)
527 (*isaphysmemunblock)();
528 }
529 }
530
531 /*
532 * Handle a NMI, possibly a machine check.
533 * return true to panic system, false to ignore.
534 */
535 int
536 isa_nmi(cd) {
537
538 log(LOG_CRIT, "\nNMI port 61 %x, port 70 %x\n", inb(0x61), inb(0x70));
539 return(0);
540 }
541
542 /*
543 * Caught a stray interrupt, notify
544 */
545 void
546 isa_strayintr(d)
547 int d;
548 {
549
550 /*
551 * Stray level 7 interrupts occur when someone raises an interrupt
552 * and then drops it before the CPU acknowledges it. This means
553 * either the device is screwed or something is cli'ing too long.
554 */
555 extern u_long intrcnt_stray;
556
557 intrcnt_stray++;
558 if (intrcnt_stray <= 5)
559 log(LOG_ERR, "stray interrupt %d\n", d);
560 if (intrcnt_stray == 5)
561 log(LOG_CRIT,"too many stray interrupts; stopped logging\n");
562 }
563
564 static beeping;
565 static void
566 sysbeepstop(int f)
567 {
568 int s = splhigh();
569
570 /* disable counter 2 */
571 disable_intr();
572 outb(PITAUX_PORT, inb(PITAUX_PORT) & ~PIT_SPKR);
573 enable_intr();
574 if (f)
575 timeout((timeout_t)sysbeepstop, (caddr_t)0, f);
576 else
577 beeping = 0;
578
579 splx(s);
580 }
581
582 void
583 sysbeep(int pitch, int period)
584 {
585 int s = splhigh();
586 static int last_pitch, last_period;
587
588 if (beeping) {
589 untimeout((timeout_t)sysbeepstop, (caddr_t)(last_period/2));
590 untimeout((timeout_t)sysbeepstop, (caddr_t)0);
591 }
592 if (!beeping || last_pitch != pitch) {
593 /*
594 * XXX - move timer stuff to clock.c.
595 */
596 disable_intr();
597 outb(TIMER_MODE, TIMER_SEL2|TIMER_16BIT|TIMER_SQWAVE);
598 outb(TIMER_CNTR2, TIMER_DIV(pitch)%256);
599 outb(TIMER_CNTR2, TIMER_DIV(pitch)/256);
600 outb(PITAUX_PORT, inb(PITAUX_PORT) | PIT_SPKR); /* enable counter 2 */
601 enable_intr();
602 }
603 last_pitch = pitch;
604 beeping = last_period = period;
605 timeout((timeout_t)sysbeepstop, (caddr_t)(period/2), period);
606
607 splx(s);
608 }
609
610 /*
611 * Pass command to keyboard controller (8042)
612 */
613 unsigned
614 kbc_8042cmd(int val)
615 {
616 while (inb(KBSTATP)&KBS_IBF);
617 if (val) outb(KBCMDP, val);
618 while (inb(KBSTATP)&KBS_IBF);
619 return (inb(KBDATAP));
620 }
621
622 /*
623 * find an ISA device in a given isa_devtab_* table, given
624 * the table to search, the expected id_driver entry, and the unit number.
625 *
626 * this function is defined in isa_device.h, and this location is debatable;
627 * i put it there because it's useless w/o, and directly operates on
628 * the other stuff in that file.
629 *
630 */
631
632 struct isa_device *find_isadev(table, driverp, unit)
633 struct isa_device *table;
634 struct isa_driver *driverp;
635 int unit;
636 {
637 if (driverp == NULL) /* sanity check */
638 return NULL;
639
640 while ((table->id_driver != driverp) || (table->id_unit != unit)) {
641 if (table->id_driver == 0)
642 return NULL;
643
644 table++;
645 }
646
647 return table;
648 }
649
650 /*
651 * Return nonzero if a (masked) irq is pending for a given device.
652 */
653 int
654 isa_irq_pending(dvp)
655 struct isa_device *dvp;
656 {
657 unsigned id_irq;
658
659 id_irq = (unsigned short) dvp->id_irq; /* XXX silly type in struct */
660 if (id_irq & 0xff)
661 return (inb(IO_ICU1) & id_irq);
662 return (inb(IO_ICU2) & (id_irq >> 8));
663 }
664