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isa.c revision 1.28.2.1
      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 1.28.2.1 1993/09/14 17:32:39 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/segments.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 icuattach __P((struct device *, struct device *, void *));
     90 
     91 struct cfdriver isacd =
     92 { NULL, "isa", isaprobe, isaattach, DV_DULL, sizeof(struct isa_softc) };
     93 
     94 int
     95 isaprobe(parent, cf, aux)
     96 	struct device *parent;
     97 	struct cfdata *cf;
     98 	void *aux;
     99 {
    100 
    101 	/* XXX should do a real probe */
    102 	isa_bustype = BUS_ISA;
    103 	return 1;
    104 }
    105 
    106 static int
    107 isasubmatch(parent, cf, aux)
    108 	struct device *parent;
    109 	struct cfdata *cf;
    110 	void *aux;
    111 {
    112 	struct	isa_attach_args *ia = aux;
    113 	int	rv;
    114 
    115 	ia->ia_iobase = cf->cf_iobase;
    116 	ia->ia_iosize = cf->cf_iosize;
    117 	if (cf->cf_irq == -1)
    118 		ia->ia_irq = IRQUNK;
    119 	else
    120 		ia->ia_irq = 1 << cf->cf_irq;
    121 	ia->ia_drq = cf->cf_drq;
    122 	ia->ia_maddr = cf->cf_maddr;
    123 	ia->ia_msize = cf->cf_msize;
    124 
    125 #ifdef DIAGNOSTIC
    126 	if (!cf->cf_driver->cd_match) {
    127 		printf("isasubmatch: no match function for `%s' device\n",
    128 			cf->cf_driver->cd_name);
    129 		panic("isasubmatch: no match function\n");
    130 	}
    131 #endif
    132 
    133 	rv = (*cf->cf_driver->cd_match)(parent, cf, aux);
    134 
    135 	if (!rv)
    136 		return 0;
    137 
    138 	if (!isa_reserveports(ia->ia_iobase, ia->ia_iosize))
    139 		return 0;
    140 
    141 	if (!isa_reservemem(ia->ia_maddr, ia->ia_msize)) {
    142 		isa_unreserveports(ia->ia_iobase, ia->ia_iosize);
    143 		return 0;
    144 	}
    145 
    146 	return 1;
    147 }
    148 
    149 void
    150 isaprint(aux, isaname)
    151 	void *aux;
    152 	char *isaname;
    153 {
    154 	struct isa_attach_args *ia = aux;
    155 
    156 	if (ia->ia_iosize)
    157 		printf(" port 0x%x", ia->ia_iobase);
    158 	if (ia->ia_iosize > 1)
    159 		printf("-0x%x", ia->ia_iobase + ia->ia_iosize - 1);
    160 	if (ia->ia_irq != IRQUNK)
    161 		printf(" irq %d", ffs(ia->ia_irq) - 1);
    162 	if (ia->ia_drq != DRQUNK)
    163 		printf(" drq %d", ia->ia_drq);
    164 	if (ia->ia_msize)
    165 		printf(" iomem 0x%x", ia->ia_maddr);
    166 	if (ia->ia_msize > 1)
    167 		printf("-0x%x", ia->ia_maddr + ia->ia_msize - 1);
    168 	/* XXXX need to print flags */
    169 }
    170 
    171 void
    172 isaattach(parent, self, aux)
    173 	struct device *parent, *self;
    174 	void *aux;
    175 {
    176 
    177 	isa_defaultirq();
    178 
    179 	enable_intr();
    180 	splhigh();
    181 	intr_enable(IRQ_SLAVE);
    182 
    183 	for (;;) {
    184 		struct cfdata *child
    185 		struct isa_attach_args ia;
    186 		child = config_search(isasubmatch, self, &ia);
    187 		if (!child)
    188 			break;
    189 		config_attach(self, child, &ia, isaprint);
    190 	}
    191 
    192 	/* and the problem is... if netmask == 0, then the loopback
    193 	 * code can do some really ugly things.
    194 	 * workaround for this: if netmask == 0, set it to 0x8000, which
    195 	 * is the value used by splsoftclock.  this is nasty, but it
    196 	 * should work until this interrupt system goes away. -- cgd
    197 	 */
    198 	if (netmask == 0)
    199 		netmask = 0x8000;	/* same as for softclock.  XXXX */
    200 
    201 	printf("biomask %x ttymask %x netmask %x impmask %x\n",
    202 	       biomask, ttymask, netmask, impmask);
    203 	splnone();
    204 }
    205 
    206 
    207 #define	IDTVEC(name)	__CONCAT(X,name)
    208 /* default interrupt vector table entries */
    209 extern	IDTVEC(intr0), IDTVEC(intr1), IDTVEC(intr2), IDTVEC(intr3),
    210 	IDTVEC(intr4), IDTVEC(intr5), IDTVEC(intr6), IDTVEC(intr7),
    211 	IDTVEC(intr8), IDTVEC(intr9), IDTVEC(intr10), IDTVEC(intr11),
    212 	IDTVEC(intr12), IDTVEC(intr13), IDTVEC(intr14), IDTVEC(intr15);
    213 
    214 static *defvec[16] = {
    215 	&IDTVEC(intr0), &IDTVEC(intr1), &IDTVEC(intr2), &IDTVEC(intr3),
    216 	&IDTVEC(intr4), &IDTVEC(intr5), &IDTVEC(intr6), &IDTVEC(intr7),
    217 	&IDTVEC(intr8), &IDTVEC(intr9), &IDTVEC(intr10), &IDTVEC(intr11),
    218 	&IDTVEC(intr12), &IDTVEC(intr13), &IDTVEC(intr14), &IDTVEC(intr15) };
    219 
    220 /* out of range default interrupt vector gate entry */
    221 extern	IDTVEC(intrdefault);
    222 
    223 /*
    224  * Fill in default interrupt table, and mask all interrupts.
    225  */
    226 void
    227 isa_defaultirq()
    228 {
    229 	int i;
    230 
    231 	/* icu vectors */
    232 	for (i = ICU_OFFSET; i < ICU_OFFSET + ICU_LEN ; i++)
    233 		setidt(i, defvec[i],  SDT_SYS386IGT, SEL_KPL);
    234 
    235 	/* out of range vectors */
    236 	for (; i < NIDT; i++)
    237 		setidt(i, &IDTVEC(intrdefault), SDT_SYS386IGT, SEL_KPL);
    238 
    239 	/* initialize 8259's */
    240 	outb(IO_ICU1, 0x11);		/* reset; program device, four bytes */
    241 	outb(IO_ICU1+1, ICU_OFFSET);	/* starting at this vector index */
    242 	outb(IO_ICU1+1, IRQ_SLAVE);
    243 #ifdef AUTO_EOI_1
    244 	outb(IO_ICU1+1, 2 | 1);		/* auto EOI, 8086 mode */
    245 #else
    246 	outb(IO_ICU1+1, 1);		/* 8086 mode */
    247 #endif
    248 	outb(IO_ICU1+1, 0xff);		/* leave interrupts masked */
    249 	outb(IO_ICU1, 0x0a);		/* default to IRR on read */
    250 #ifdef REORDER_IRQ
    251 	outb(IO_ICU1, 0xc0 | (3 - 1));	/* pri order 3-7, 0-2 (com2 first) */
    252 #endif
    253 
    254 	outb(IO_ICU2, 0x11);		/* reset; program device, four bytes */
    255 	outb(IO_ICU2+1, ICU_OFFSET+8);	/* staring at this vector index */
    256 	outb(IO_ICU2+1, ffs(IRQ_SLAVE)-1);
    257 #ifdef AUTO_EOI_2
    258 	outb(IO_ICU2+1, 2 | 1);		/* auto EOI, 8086 mode */
    259 #else
    260 	outb(IO_ICU2+1, 1);		/* 8086 mode */
    261 #endif
    262 	outb(IO_ICU2+1, 0xff);		/* leave interrupts masked */
    263 	outb(IO_ICU2, 0x0a);		/* default to IRR on read */
    264 }
    265 
    266 
    267 /* XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
    268 
    269 int
    270 config_isadev(isdp, mp)
    271 	struct isa_device *isdp;
    272 	u_int *mp;
    273 {
    274 	if (isdp->id_irq) {
    275 		int intrno;
    276 
    277 		intrno = ffs(isdp->id_irq)-1;
    278 		setidt(ICU_OFFSET+intrno, isdp->id_intr,
    279 			 SDT_SYS386IGT, SEL_KPL);
    280 		if(mp)
    281 			INTRMASK(*mp,isdp->id_irq);
    282 		INTREN(isdp->id_irq);
    283 	}
    284 }
    285 
    286 
    287 /* region of physical memory known to be contiguous */
    288 vm_offset_t isaphysmem;
    289 static caddr_t bouncebuf[8];		/* XXX */
    290 static caddr_t bounced[8];		/* XXX */
    291 static vm_size_t bouncesize[8];		/* XXX */
    292 #define MAXDMASZ 512			/* XXX */
    293 
    294 /* high byte of address is stored in this port for i-th dma channel */
    295 static short dmapageport[8] =
    296 	{ 0x87, 0x83, 0x81, 0x82, 0x8f, 0x8b, 0x89, 0x8a };
    297 
    298 /*
    299  * isa_dmacascade(): program 8237 DMA controller channel to accept
    300  * external dma control by a board.
    301  */
    302 void
    303 at_dma_cascade(chan)
    304 	unsigned chan;
    305 {
    306 #ifdef DEBUG
    307 	if (chan > 7)
    308 		panic("at_dma_cascade: impossible request");
    309 #endif
    310 
    311 	/* set dma channel mode, and set dma channel mode */
    312 	if ((chan & 4) == 0) {
    313 		outb(DMA1_MODE, DMA37MD_CASCADE | chan);
    314 		outb(DMA1_SMSK, chan);
    315 	} else {
    316 		outb(DMA2_MODE, DMA37MD_CASCADE | (chan & 3));
    317 		outb(DMA2_SMSK, chan & 3);
    318 	}
    319 }
    320 
    321 /*
    322  * at_dma(): program 8237 DMA controller channel, avoid page alignment
    323  * problems by using a bounce buffer.
    324  */
    325 void
    326 at_dma(flags, addr, nbytes, chan)
    327 	int read;
    328 	caddr_t addr;
    329 	vm_size_t nbytes;
    330 	unsigned chan;
    331 {
    332 	vm_offset_t phys;
    333 	int waport;
    334 	caddr_t newaddr;
    335 
    336 ppp	if (    chan > 7
    337 	    || (chan < 4 && nbytes > (1<<16))
    338 	    || (chan >= 4 && (nbytes > (1<<17) || (u_int)addr & 1)))
    339 		panic("isa_dmastart: impossible request");
    340 
    341 	if (at_dma_rangecheck(addr, nbytes, chan)) {
    342 		panic("bounce buffers don't work yet\n");
    343 		/* XXX totally braindead; NBPG is not enough */
    344 		if (bouncebuf[chan] == 0)
    345 			bouncebuf[chan] =
    346 				/*(caddr_t)malloc(MAXDMASZ, M_TEMP, M_WAITOK);*/
    347 				(caddr_t) isaphysmem + NBPG*chan;
    348 		bouncesize[chan] = nbytes;
    349 		newaddr = bouncebuf[chan];
    350 		/* copy bounce buffer on write */
    351 		if (!read)
    352 			bcopy(addr, newaddr, nbytes);
    353 		else
    354 			bounced[chan] = addr;
    355 		addr = newaddr;
    356 	}
    357 
    358 	/* translate to physical */
    359 	phys = pmap_extract(pmap_kernel(), (vm_offset_t)addr);
    360 
    361 	if ((chan & 4) == 0) {
    362 		/*
    363 		 * Program one of DMA channels 0..3.  These are
    364 		 * byte mode channels.
    365 		 */
    366 		/* set dma channel mode, and reset address ff */
    367 		if (read)
    368 			outb(DMA1_MODE, DMA37MD_SINGLE|DMA37MD_WRITE|chan);
    369 		else
    370 			outb(DMA1_MODE, DMA37MD_SINGLE|DMA37MD_READ|chan);
    371 		outb(DMA1_FFC, 0);
    372 
    373 		/* send start address */
    374 		waport =  DMA1_CHN(chan);
    375 		outb(waport, phys);
    376 		outb(waport, phys>>8);
    377 		outb(dmapageport[chan], phys>>16);
    378 
    379 		/* send count */
    380 		outb(waport + 1, --nbytes);
    381 		outb(waport + 1, nbytes>>8);
    382 
    383 		/* unmask channel */
    384 		outb(DMA1_SMSK, chan);
    385 	} else {
    386 		/*
    387 		 * Program one of DMA channels 4..7.  These are
    388 		 * word mode channels.
    389 		 */
    390 		/* set dma channel mode, and reset address ff */
    391 		if (read)
    392 			outb(DMA2_MODE, DMA37MD_SINGLE|DMA37MD_WRITE|(chan&3));
    393 		else
    394 			outb(DMA2_MODE, DMA37MD_SINGLE|DMA37MD_READ|(chan&3));
    395 		outb(DMA2_FFC, 0);
    396 
    397 		/* send start address */
    398 		waport = DMA2_CHN(chan - 4);
    399 		outb(waport, phys>>1);
    400 		outb(waport, phys>>9);
    401 		outb(dmapageport[chan], phys>>16);
    402 
    403 		/* send count */
    404 		nbytes >>= 1;
    405 		outb(waport + 2, --nbytes);
    406 		outb(waport + 2, nbytes>>8);
    407 
    408 		/* unmask channel */
    409 		outb(DMA2_SMSK, chan & 3);
    410 	}
    411 }
    412 
    413 void
    414 at_dma_terminate(int flags, caddr_t addr, int nbytes, int chan)
    415 {
    416 
    417 	if (bounced[chan]) {
    418 		bcopy(bouncebuf[chan], bounced[chan], bouncesize[chan]);
    419 		bounced[chan] = 0;
    420 	}
    421 }
    422 
    423 /*
    424  * Check for problems with the address range of a DMA transfer
    425  * (non-contiguous physical pages, outside of bus address space,
    426  * crossing DMA page boundaries).
    427  * Return true if special handling needed.
    428  */
    429 
    430 int
    431 at_dma_rangecheck(caddr_t va, unsigned length, unsigned chan) {
    432 	vm_offset_t phys, priorpage = 0, endva;
    433 	u_int dma_pgmsk = (chan & 4) ?  ~(128*1024-1) : ~(64*1024-1);
    434 
    435 	endva = (vm_offset_t)round_page(va + length);
    436 	for (; va < (caddr_t) endva ; va += NBPG) {
    437 		phys = trunc_page(pmap_extract(pmap_kernel(), (vm_offset_t)va));
    438 		if (phys == 0)
    439 			panic("isa_dmacheck: no physical page present");
    440 		if (phys > physmem)
    441 			return (1);
    442 		if (priorpage) {
    443 			if (priorpage + NBPG != phys)
    444 				return (1);
    445 			/* check if crossing a DMA page boundary */
    446 			if (((u_int)priorpage ^ (u_int)phys) & dma_pgmsk)
    447 				return (1);
    448 		}
    449 		priorpage = phys;
    450 	}
    451 	return (0);
    452 }
    453 
    454 /* head of queue waiting for physmem to become available */
    455 struct buf isa_physmemq;
    456 
    457 /* blocked waiting for resource to become free for exclusive use */
    458 static isaphysmemflag;
    459 /* if waited for and call requested when free (B_CALL) */
    460 static void (*isaphysmemunblock)(); /* XXX needs to be a list */
    461 
    462 /*
    463  * Allocate contiguous physical memory for transfer, returning
    464  * a *virtual* address to region. May block waiting for resource.
    465  * (assumed to be called at splbio())
    466  */
    467 caddr_t
    468 isa_allocphysmem(caddr_t va, unsigned length, void (*func)()) {
    469 
    470 	isaphysmemunblock = func;
    471 	while (isaphysmemflag & B_BUSY) {
    472 		isaphysmemflag |= B_WANTED;
    473 		sleep((caddr_t)&isaphysmemflag, PRIBIO);
    474 	}
    475 	isaphysmemflag |= B_BUSY;
    476 
    477 	return((caddr_t)isaphysmem);
    478 }
    479 
    480 /*
    481  * Free contiguous physical memory used for transfer.
    482  * (assumed to be called at splbio())
    483  */
    484 void
    485 isa_freephysmem(caddr_t va, unsigned length) {
    486 
    487 	isaphysmemflag &= ~B_BUSY;
    488 	if (isaphysmemflag & B_WANTED) {
    489 		isaphysmemflag &= B_WANTED;
    490 		wakeup((caddr_t)&isaphysmemflag);
    491 		if (isaphysmemunblock)
    492 			(*isaphysmemunblock)();
    493 	}
    494 }
    495 
    496 /*
    497  * Handle a NMI, possibly a machine check.
    498  * return true to panic system, false to ignore.
    499  */
    500 int
    501 isa_nmi(cd) {
    502 
    503 	log(LOG_CRIT, "\nNMI port 61 %x, port 70 %x\n", inb(0x61), inb(0x70));
    504 	return(0);
    505 }
    506 
    507 /*
    508  * Caught a stray interrupt, notify
    509  */
    510 void
    511 isa_strayintr(d)
    512 	int d;
    513 {
    514 
    515 	/*
    516 	 * Stray level 7 interrupts occur when someone raises an interrupt
    517 	 * and then drops it before the CPU acknowledges it.  This means
    518 	 * either the device is screwed or something is cli'ing too long.
    519 	 */
    520 	extern u_long intrcnt_stray;
    521 
    522 	intrcnt_stray++;
    523 	if (intrcnt_stray <= 5)
    524 		log(LOG_ERR, "stray interrupt %d\n", d);
    525 	if (intrcnt_stray == 5)
    526 		log(LOG_CRIT,"too many stray interrupts; stopped logging\n");
    527 }
    528 
    529 static beeping;
    530 static void
    531 sysbeepstop(int f)
    532 {
    533 	int s = splhigh();
    534 
    535 	/* disable counter 2 */
    536 	disable_intr();
    537 	outb(PITAUX_PORT, inb(PITAUX_PORT) & ~PIT_SPKR);
    538 	enable_intr();
    539 	if (f)
    540 		timeout((timeout_t)sysbeepstop, (caddr_t)0, f);
    541 	else
    542 		beeping = 0;
    543 
    544 	splx(s);
    545 }
    546 
    547 void
    548 sysbeep(int pitch, int period)
    549 {
    550 	int s = splhigh();
    551 	static int last_pitch, last_period;
    552 
    553 	if (beeping) {
    554 		untimeout((timeout_t)sysbeepstop, (caddr_t)(last_period/2));
    555 		untimeout((timeout_t)sysbeepstop, (caddr_t)0);
    556 	}
    557 	if (!beeping || last_pitch != pitch) {
    558 		/*
    559 	 	* XXX - move timer stuff to clock.c.
    560 	 	*/
    561 		disable_intr();
    562 		outb(TIMER_MODE, TIMER_SEL2|TIMER_16BIT|TIMER_SQWAVE);
    563 		outb(TIMER_CNTR2, TIMER_DIV(pitch)%256);
    564 		outb(TIMER_CNTR2, TIMER_DIV(pitch)/256);
    565 		outb(PITAUX_PORT, inb(PITAUX_PORT) | PIT_SPKR);	/* enable counter 2 */
    566 		enable_intr();
    567 	}
    568 	last_pitch = pitch;
    569 	beeping = last_period = period;
    570 	timeout((timeout_t)sysbeepstop, (caddr_t)(period/2), period);
    571 
    572 	splx(s);
    573 }
    574 
    575 /*
    576  * Pass command to keyboard controller (8042)
    577  */
    578 unsigned
    579 kbc_8042cmd(int val)
    580 {
    581 	while (inb(KBSTATP)&KBS_IBF);
    582 	if (val) outb(KBCMDP, val);
    583 	while (inb(KBSTATP)&KBS_IBF);
    584 	return (inb(KBDATAP));
    585 }
    586 
    587 /*
    588  * find an ISA device in a given isa_devtab_* table, given
    589  * the table to search, the expected id_driver entry, and the unit number.
    590  *
    591  * this function is defined in isa_device.h, and this location is debatable;
    592  * i put it there because it's useless w/o, and directly operates on
    593  * the other stuff in that file.
    594  *
    595  */
    596 
    597 struct isa_device *find_isadev(table, driverp, unit)
    598 	struct isa_device *table;
    599 	struct isa_driver *driverp;
    600 	int unit;
    601 {
    602 	if (driverp == NULL) /* sanity check */
    603 		return NULL;
    604 
    605 	while ((table->id_driver != driverp) || (table->id_unit != unit)) {
    606 		if (table->id_driver == 0)
    607 			return NULL;
    608 
    609 		table++;
    610         }
    611 
    612 	return table;
    613 }
    614 
    615 /*
    616  * Return nonzero if a (masked) irq is pending for a given device.
    617  */
    618 int
    619 isa_irq_pending(dvp)
    620 	struct isa_device *dvp;
    621 {
    622 	unsigned id_irq;
    623 
    624 	id_irq = (unsigned short) dvp->id_irq;	/* XXX silly type in struct */
    625 	if (id_irq & 0xff)
    626 		return (inb(IO_ICU1) & id_irq);
    627 	return (inb(IO_ICU2) & (id_irq >> 8));
    628 }
    629