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isa.c revision 1.4
      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  *	@(#)isa.c	7.2 (Berkeley) 5/13/91
     37  */
     38 static char rcsid[] = "$Header: /tank/opengrok/rsync2/NetBSD/src/sys/dev/isa/isa.c,v 1.4 1993/04/09 13:43:40 cgd Exp $";
     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 "rlist.h"
     59 #include "machine/segments.h"
     60 #include "vm/vm.h"
     61 #include "i386/isa/isa_device.h"
     62 #include "i386/isa/isa.h"
     63 #include "i386/isa/icu.h"
     64 #include "i386/isa/ic/i8237.h"
     65 #include "i386/isa/ic/i8042.h"
     66 
     67 /*
     68 **  Register definitions for DMA controller 1 (channels 0..3):
     69 */
     70 #define	DMA1_CHN(c)	(IO_DMA1 + 1*(2*(c)))	/* addr reg for channel c */
     71 #define	DMA1_SMSK	(IO_DMA1 + 1*10)	/* single mask register */
     72 #define	DMA1_MODE	(IO_DMA1 + 1*11)	/* mode register */
     73 #define	DMA1_FFC	(IO_DMA1 + 1*12)	/* clear first/last FF */
     74 
     75 /*
     76 **  Register definitions for DMA controller 2 (channels 4..7):
     77 */
     78 #define	DMA2_CHN(c)	(IO_DMA1 + 2*(2*(c)))	/* addr reg for channel c */
     79 #define	DMA2_SMSK	(IO_DMA2 + 2*10)	/* single mask register */
     80 #define	DMA2_MODE	(IO_DMA2 + 2*11)	/* mode register */
     81 #define	DMA2_FFC	(IO_DMA2 + 2*12)	/* clear first/last FF */
     82 
     83 int config_isadev(struct isa_device *, u_short *);
     84 #ifdef notyet
     85 struct rlist *isa_iomem;
     86 
     87 /*
     88  * Configure all ISA devices
     89  */
     90 isa_configure() {
     91 	struct isa_device *dvp;
     92 	struct isa_driver *dp;
     93 
     94 	splhigh();
     95 	INTREN(IRQ_SLAVE);
     96 	/*rlist_free(&isa_iomem, 0xa0000, 0xfffff);*/
     97 	for (dvp = isa_devtab_tty; dvp; dvp++)
     98 			(void) config_isadev(dvp, &ttymask);
     99 	for (dvp = isa_devtab_bio; dvp; dvp++)
    100 			(void) config_isadev(dvp, &biomask);
    101 	for (dvp = isa_devtab_net; dvp; dvp++)
    102 			(void) config_isadev(dvp, &netmask);
    103 	for (dvp = isa_devtab_null; dvp; dvp++)
    104 			(void) config_isadev(dvp, 0);
    105 #include "sl.h"
    106 #if NSL > 0
    107 	netmask |= ttymask;
    108 	ttymask |= netmask;
    109 #endif
    110 /* printf("biomask %x ttymask %x netmask %x\n", biomask, ttymask, netmask); */
    111 	splnone();
    112 }
    113 
    114 /*
    115  * Configure an ISA device.
    116  */
    117 config_isadev(isdp, mp)
    118 	struct isa_device *isdp;
    119 	u_short *mp;
    120 {
    121 	struct isa_driver *dp;
    122 	static short drqseen, irqseen;
    123 
    124 	if (dp = isdp->id_driver) {
    125 		/* if a device with i/o memory, convert to virtual address */
    126 		if (isdp->id_maddr) {
    127 			extern unsigned int atdevbase;
    128 
    129 			isdp->id_maddr -= IOM_BEGIN;
    130 			isdp->id_maddr += atdevbase;
    131 		}
    132 		isdp->id_alive = (*dp->probe)(isdp);
    133 		if (isdp->id_alive) {
    134 
    135 			printf("%s%d at port 0x%x ", dp->name,
    136 				isdp->id_unit, isdp->id_iobase);
    137 
    138 			/* check for conflicts */
    139 			if (irqseen & isdp->id_irq) {
    140 				printf("INTERRUPT CONFLICT - irq%d\n",
    141 					ffs(isdp->id_irq) - 1);
    142 				return (0);
    143 			}
    144 			if (isdp->id_drq != -1
    145 				&& (drqseen & (1<<isdp->id_drq))) {
    146 				printf("DMA CONFLICT - drq%d\n", isdp->id_drq);
    147 				return (0);
    148 			}
    149 			/* NEED TO CHECK IOMEM CONFLICT HERE */
    150 
    151 			/* allocate and wire in device */
    152 			if(isdp->id_irq) {
    153 				int intrno;
    154 
    155 				intrno = ffs(isdp->id_irq)-1;
    156 				printf("irq %d ", intrno);
    157 				INTREN(isdp->id_irq);
    158 				if(mp)INTRMASK(*mp,isdp->id_irq);
    159 				setidt(NRSVIDT + intrno, isdp->id_intr,
    160 					 SDT_SYS386IGT, SEL_KPL);
    161 				irqseen |= isdp->id_irq;
    162 			}
    163 			if (isdp->id_drq != -1) {
    164 				printf("drq %d ", isdp->id_drq);
    165 				drqseen |=  1 << isdp->id_drq;
    166 			}
    167 
    168 			(*dp->attach)(isdp);
    169 
    170 			printf("on isa\n");
    171 		}
    172 		return (1);
    173 	} else	return(0);
    174 }
    175 #else /* notyet */
    176 /*
    177  * Configure all ISA devices
    178  */
    179 isa_configure() {
    180 	struct isa_device *dvp;
    181 	struct isa_driver *dp;
    182 
    183 	splhigh();
    184 	INTREN(IRQ_SLAVE);
    185 	for (dvp = isa_devtab_tty; config_isadev(dvp,&ttymask); dvp++);
    186 	for (dvp = isa_devtab_bio; config_isadev(dvp,&biomask); dvp++);
    187 	for (dvp = isa_devtab_net; config_isadev(dvp,&netmask); dvp++);
    188 	for (dvp = isa_devtab_null; config_isadev(dvp,0); dvp++);
    189 #include "sl.h"
    190 #if NSL > 0
    191 	netmask |= ttymask;
    192 	ttymask |= netmask;
    193 #endif
    194 	/* biomask |= ttymask ;  can some tty devices use buffers? */
    195 	/* printf("biomask %x ttymask %x netmask %x\n", biomask, ttymask, netmask); */
    196 	splnone();
    197 }
    198 
    199 /*
    200  * Configure an ISA device.
    201  */
    202 config_isadev(isdp, mp)
    203 	struct isa_device *isdp;
    204 	u_short *mp;
    205 {
    206 	struct isa_driver *dp;
    207 
    208 	if (dp = isdp->id_driver) {
    209 		if (isdp->id_maddr) {
    210 			extern u_int atdevbase;
    211 
    212 			isdp->id_maddr -= 0xa0000;
    213 			isdp->id_maddr += atdevbase;
    214 		}
    215 		isdp->id_alive = (*dp->probe)(isdp);
    216 		if (isdp->id_alive) {
    217 			printf("%s%d", dp->name, isdp->id_unit);
    218 			printf(" at 0x%x-0x%x ", isdp->id_iobase,
    219 				isdp->id_iobase + isdp->id_alive);
    220 			if(isdp->id_irq)
    221 				printf("irq %d ", ffs(isdp->id_irq)-1);
    222 			if (isdp->id_drq != -1)
    223 				printf("drq %d ", isdp->id_drq);
    224 			if (isdp->id_maddr != 0)
    225 				printf("maddr 0x%x ", kvtop(isdp->id_maddr));
    226 			if (isdp->id_msize != 0)
    227 				printf("msize %d ", isdp->id_msize);
    228 			if (isdp->id_flags != 0)
    229 				printf("flags 0x%x ", isdp->id_flags);
    230 			printf("on isa\n");
    231 
    232 			(*dp->attach)(isdp);
    233 			if(isdp->id_irq) {
    234 				int intrno;
    235 
    236 				intrno = ffs(isdp->id_irq)-1;
    237 				INTREN(isdp->id_irq);
    238 				if(mp)
    239 					INTRMASK(*mp,isdp->id_irq);
    240 				setidt(ICU_OFFSET+intrno, isdp->id_intr,
    241 					 SDT_SYS386IGT, SEL_KPL);
    242 			}
    243 		}
    244 		return (1);
    245 	} else	return(0);
    246 }
    247 #endif /* (!) notyet */
    248 
    249 #define	IDTVEC(name)	__CONCAT(X,name)
    250 /* default interrupt vector table entries */
    251 extern	IDTVEC(intr0), IDTVEC(intr1), IDTVEC(intr2), IDTVEC(intr3),
    252 	IDTVEC(intr4), IDTVEC(intr5), IDTVEC(intr6), IDTVEC(intr7),
    253 	IDTVEC(intr8), IDTVEC(intr9), IDTVEC(intr10), IDTVEC(intr11),
    254 	IDTVEC(intr12), IDTVEC(intr13), IDTVEC(intr14), IDTVEC(intr15);
    255 
    256 static *defvec[16] = {
    257 	&IDTVEC(intr0), &IDTVEC(intr1), &IDTVEC(intr2), &IDTVEC(intr3),
    258 	&IDTVEC(intr4), &IDTVEC(intr5), &IDTVEC(intr6), &IDTVEC(intr7),
    259 	&IDTVEC(intr8), &IDTVEC(intr9), &IDTVEC(intr10), &IDTVEC(intr11),
    260 	&IDTVEC(intr12), &IDTVEC(intr13), &IDTVEC(intr14), &IDTVEC(intr15) };
    261 
    262 /* out of range default interrupt vector gate entry */
    263 extern	IDTVEC(intrdefault);
    264 
    265 /*
    266  * Fill in default interrupt table (in case of spuruious interrupt
    267  * during configuration of kernel, setup interrupt control unit
    268  */
    269 isa_defaultirq() {
    270 	int i;
    271 
    272 	/* icu vectors */
    273 	for (i = NRSVIDT ; i < NRSVIDT+ICU_LEN ; i++)
    274 		setidt(i, defvec[i],  SDT_SYS386IGT, SEL_KPL);
    275 
    276 	/* out of range vectors */
    277 	for (i = NRSVIDT; i < NIDT; i++)
    278 		setidt(i, &IDTVEC(intrdefault), SDT_SYS386IGT, SEL_KPL);
    279 
    280 	/* clear npx intr latch */
    281 	outb(0xf1,0);
    282 
    283 	/* initialize 8259's */
    284 	outb(IO_ICU1, 0x11);		/* reset; program device, four bytes */
    285 	outb(IO_ICU1+1, NRSVIDT);	/* starting at this vector index */
    286 	outb(IO_ICU1+1, 1<<2);		/* slave on line 2 */
    287 	outb(IO_ICU1+1, 1);		/* 8086 mode */
    288 	outb(IO_ICU1+1, 0xff);		/* leave interrupts masked */
    289 	outb(IO_ICU1, 2);		/* default to ISR on read */
    290 
    291 	outb(IO_ICU2, 0x11);		/* reset; program device, four bytes */
    292 	outb(IO_ICU2+1, NRSVIDT+8);	/* staring at this vector index */
    293 	outb(IO_ICU2+1,2);		/* my slave id is 2 */
    294 	outb(IO_ICU2+1,1);		/* 8086 mode */
    295 	outb(IO_ICU2+1, 0xff);		/* leave interrupts masked */
    296 	outb(IO_ICU2, 2);		/* default to ISR on read */
    297 }
    298 
    299 /* region of physical memory known to be contiguous */
    300 vm_offset_t isaphysmem;
    301 static caddr_t dma_bounce[8];		/* XXX */
    302 static char bounced[8];		/* XXX */
    303 #define MAXDMASZ 512		/* XXX */
    304 
    305 /* high byte of address is stored in this port for i-th dma channel */
    306 static short dmapageport[8] =
    307 	{ 0x87, 0x83, 0x81, 0x82, 0x8f, 0x8b, 0x89, 0x8a };
    308 
    309 /*
    310  * isa_dmacascade(): program 8237 DMA controller channel to accept
    311  * external dma control by a board.
    312  */
    313 void isa_dmacascade(unsigned chan)
    314 {
    315 	if (chan > 7)
    316 		panic("isa_dmacascade: impossible request");
    317 
    318 	/* set dma channel mode, and set dma channel mode */
    319 	if ((chan & 4) == 0) {
    320 		outb(DMA1_MODE, DMA37MD_CASCADE | chan);
    321 		outb(DMA1_SMSK, chan);
    322 	} else {
    323 		outb(DMA2_MODE, DMA37MD_CASCADE | (chan & 3));
    324 		outb(DMA2_SMSK, chan & 3);
    325 	}
    326 }
    327 
    328 /*
    329  * isa_dmastart(): program 8237 DMA controller channel, avoid page alignment
    330  * problems by using a bounce buffer.
    331  */
    332 void isa_dmastart(int flags, caddr_t addr, unsigned nbytes, unsigned chan)
    333 {	vm_offset_t phys;
    334 	int waport;
    335 	caddr_t newaddr;
    336 
    337 	if (    chan > 7
    338 	    || (chan < 4 && nbytes > (1<<16))
    339 	    || (chan >= 4 && (nbytes > (1<<17) || (u_int)addr & 1)))
    340 		panic("isa_dmastart: impossible request");
    341 
    342 	if (isa_dmarangecheck(addr, nbytes, chan)) {
    343 		if (dma_bounce[chan] == 0)
    344 			dma_bounce[chan] =
    345 				/*(caddr_t)malloc(MAXDMASZ, M_TEMP, M_WAITOK);*/
    346 				(caddr_t) isaphysmem + NBPG*chan;
    347 		bounced[chan] = 1;
    348 		newaddr = dma_bounce[chan];
    349 		*(int *) newaddr = 0;	/* XXX */
    350 
    351 		/* copy bounce buffer on write */
    352 		if (!(flags & B_READ))
    353 			bcopy(addr, newaddr, nbytes);
    354 		addr = newaddr;
    355 	}
    356 
    357 	/* translate to physical */
    358 	phys = pmap_extract(pmap_kernel(), (vm_offset_t)addr);
    359 
    360 	if ((chan & 4) == 0) {
    361 		/*
    362 		 * Program one of DMA channels 0..3.  These are
    363 		 * byte mode channels.
    364 		 */
    365 		/* set dma channel mode, and reset address ff */
    366 		if (flags & B_READ)
    367 			outb(DMA1_MODE, DMA37MD_SINGLE|DMA37MD_WRITE|chan);
    368 		else
    369 			outb(DMA1_MODE, DMA37MD_SINGLE|DMA37MD_READ|chan);
    370 		outb(DMA1_FFC, 0);
    371 
    372 		/* send start address */
    373 		waport =  DMA1_CHN(chan);
    374 		outb(waport, phys);
    375 		outb(waport, phys>>8);
    376 		outb(dmapageport[chan], phys>>16);
    377 
    378 		/* send count */
    379 		outb(waport + 1, --nbytes);
    380 		outb(waport + 1, nbytes>>8);
    381 
    382 		/* unmask channel */
    383 		outb(DMA1_SMSK, chan);
    384 	} else {
    385 		/*
    386 		 * Program one of DMA channels 4..7.  These are
    387 		 * word mode channels.
    388 		 */
    389 		/* set dma channel mode, and reset address ff */
    390 		if (flags & B_READ)
    391 			outb(DMA2_MODE, DMA37MD_SINGLE|DMA37MD_WRITE|(chan&3));
    392 		else
    393 			outb(DMA2_MODE, DMA37MD_SINGLE|DMA37MD_READ|(chan&3));
    394 		outb(DMA2_FFC, 0);
    395 
    396 		/* send start address */
    397 		waport = DMA2_CHN(chan - 4);
    398 		outb(waport, phys>>1);
    399 		outb(waport, phys>>9);
    400 		outb(dmapageport[chan], phys>>16);
    401 
    402 		/* send count */
    403 		nbytes >>= 1;
    404 		outb(waport + 2, --nbytes);
    405 		outb(waport + 2, nbytes>>8);
    406 
    407 		/* unmask channel */
    408 		outb(DMA2_SMSK, chan & 3);
    409 	}
    410 }
    411 
    412 void isa_dmadone(int flags, caddr_t addr, int nbytes, int chan)
    413 {
    414 
    415 	/* copy bounce buffer on read */
    416 	/*if ((flags & (B_PHYS|B_READ)) == (B_PHYS|B_READ))*/
    417 	if (bounced[chan]) {
    418 		bcopy(dma_bounce[chan], addr, nbytes);
    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 isa_dmarangecheck(caddr_t va, unsigned length, unsigned chan) {
    431 	vm_offset_t phys, priorpage = 0, endva;
    432 	u_int dma_pgmsk = (chan & 4) ?  ~(128*1024-1) : ~(64*1024-1);
    433 
    434 	endva = (vm_offset_t)round_page(va + length);
    435 	for (; va < (caddr_t) endva ; va += NBPG) {
    436 		phys = trunc_page(pmap_extract(pmap_kernel(), (vm_offset_t)va));
    437 #define ISARAM_END	RAM_END
    438 		if (phys == 0)
    439 			panic("isa_dmacheck: no physical page present");
    440 		if (phys > ISARAM_END)
    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)(); /* 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(&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(&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 isa_nmi(cd) {
    501 
    502 	log(LOG_CRIT, "\nNMI port 61 %x, port 70 %x\n", inb(0x61), inb(0x70));
    503 	return(0);
    504 }
    505 
    506 /*
    507  * Caught a stray interrupt, notify
    508  */
    509 isa_strayintr(d) {
    510 
    511 	/* DON'T BOTHER FOR NOW! */
    512 	/* for some reason, we get bursts of intr #7, even if not enabled! */
    513 	/*
    514 	 * Well the reason you got bursts of intr #7 is because someone
    515 	 * raised an interrupt line and dropped it before the 8259 could
    516 	 * prioritize it.  This is documented in the intel data book.  This
    517 	 * means you have BAD hardware!  I have changed this so that only
    518 	 * the first 10 get logged, then it quits logging them, and puts
    519 	 * out a special message. rgrimes 3/25/1993
    520 	 */
    521 	extern u_long isa_stray_intrcnt;
    522 
    523 	isa_stray_intrcnt++;
    524 	if (isa_stray_intrcnt <= 10)
    525 		log(LOG_ERR,"ISA strayintr %x\n", d);
    526 	if (isa_stray_intrcnt == 10)
    527 		log(LOG_CRIT,"Too many ISA strayintr not logging any more\n");
    528 }
    529 
    530 /*
    531  * Wait "n" microseconds. Relies on timer 0 to have 1Mhz clock, regardless
    532  * of processor board speed. Note: timer had better have been programmed
    533  * before this is first used!
    534  */
    535 DELAY(n) {
    536 	int tick = getit(0,0) & 1;
    537 
    538 	while (n--) {
    539 		/* wait approximately 1 micro second */
    540 		while (tick == getit(0,0) & 1) ;
    541 
    542 		tick = getit(0,0) & 1;
    543 	}
    544 }
    545 
    546 getit(unit, timer) {
    547 	int port = (unit ? IO_TIMER2 : IO_TIMER1) + timer, val;
    548 
    549 	val = inb(port);
    550 	val = (inb(port) << 8) + val;
    551 	return (val);
    552 }
    553 
    554 extern int hz;
    555 
    556 static beeping;
    557 static
    558 sysbeepstop(f)
    559 {
    560 	/* disable counter 2 */
    561 	outb(0x61, inb(0x61) & 0xFC);
    562 	if (f)
    563 		timeout(sysbeepstop, 0, f);
    564 	else
    565 		beeping = 0;
    566 }
    567 
    568 void sysbeep(int pitch, int period)
    569 {
    570 
    571 	outb(0x61, inb(0x61) | 3);	/* enable counter 2 */
    572 	outb(0x43, 0xb6);	/* set command for counter 2, 2 byte write */
    573 
    574 	outb(0x42, pitch);
    575 	outb(0x42, (pitch>>8));
    576 
    577 	if (!beeping) {
    578 		beeping = period;
    579 		timeout(sysbeepstop, period/2, period);
    580 	}
    581 }
    582 
    583 /*
    584  * Pass command to keyboard controller (8042)
    585  */
    586 unsigned kbc_8042cmd(val) {
    587 
    588 	while (inb(KBSTATP)&KBS_IBF);
    589 	if (val) outb(KBCMDP, val);
    590 	while (inb(KBSTATP)&KBS_IBF);
    591 	return (inb(KBDATAP));
    592 }
    593