xref: /freebsd/sys/i386/i386/bios.c (revision b601c69bdbe8755d26570261d7fd4c02ee4eff74)
1 /*-
2  * Copyright (c) 1997 Michael Smith
3  * Copyright (c) 1998 Jonathan Lemon
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  *
27  * $FreeBSD$
28  */
29 
30 /*
31  * Code for dealing with the BIOS in x86 PC systems.
32  */
33 
34 #include "isa.h"
35 
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/kernel.h>
39 #include <sys/malloc.h>
40 #include <sys/bus.h>
41 #include <vm/vm.h>
42 #include <vm/pmap.h>
43 #include <machine/md_var.h>
44 #include <machine/segments.h>
45 #include <machine/stdarg.h>
46 #include <machine/vmparam.h>
47 #include <machine/pc/bios.h>
48 #include <isa/pnpreg.h>
49 #include <isa/pnpvar.h>
50 #if NISA > 0
51 #include <isa/isavar.h>
52 #endif
53 
54 #define BIOS_START	0xe0000
55 #define BIOS_SIZE	0x20000
56 
57 /* exported lookup results */
58 struct bios32_SDentry		PCIbios = {entry : 0};
59 struct PnPBIOS_table		*PnPBIOStable = 0;
60 
61 static u_int			bios32_SDCI = 0;
62 
63 /* start fairly early */
64 static void			bios32_init(void *junk);
65 SYSINIT(bios32, SI_SUB_CPU, SI_ORDER_ANY, bios32_init, NULL);
66 
67 /*
68  * bios32_init
69  *
70  * Locate various bios32 entities.
71  */
72 static void
73 bios32_init(void *junk)
74 {
75     u_long			sigaddr;
76     struct bios32_SDheader	*sdh;
77     struct PnPBIOS_table	*pt;
78     u_int8_t			ck, *cv;
79     int				i;
80     char			*p;
81 
82     /*
83      * BIOS32 Service Directory, PCI BIOS
84      */
85 
86     /* look for the signature */
87     if ((sigaddr = bios_sigsearch(0, "_32_", 4, 16, 0)) != 0) {
88 
89 	/* get a virtual pointer to the structure */
90 	sdh = (struct bios32_SDheader *)(uintptr_t)BIOS_PADDRTOVADDR(sigaddr);
91 	for (cv = (u_int8_t *)sdh, ck = 0, i = 0; i < (sdh->len * 16); i++) {
92 	    ck += cv[i];
93 	}
94 	/* If checksum is OK, enable use of the entrypoint */
95 	if ((ck == 0) && (sdh->entry < (BIOS_START + BIOS_SIZE))) {
96 	    bios32_SDCI = BIOS_PADDRTOVADDR(sdh->entry);
97 	    if (bootverbose) {
98 		printf("bios32: Found BIOS32 Service Directory header at %p\n", sdh);
99 		printf("bios32: Entry = 0x%x (%x)  Rev = %d  Len = %d\n",
100 		       sdh->entry, bios32_SDCI, sdh->revision, sdh->len);
101 	    }
102 
103 #ifndef PC98
104 	    /* Allow user override of PCI BIOS search */
105 	    if (((p = getenv("machdep.bios.pci")) == NULL) || strcmp(p, "disable")) {
106 
107 		/* See if there's a PCI BIOS entrypoint here */
108 		PCIbios.ident.id = 0x49435024;	/* PCI systems should have this */
109 		if (!bios32_SDlookup(&PCIbios) && bootverbose)
110 		    printf("pcibios: PCI BIOS entry at 0x%x+0x%x\n", PCIbios.base, PCIbios.entry);
111 	    }
112 #endif
113 	} else {
114 	    printf("bios32: Bad BIOS32 Service Directory\n");
115 	}
116     }
117 
118     /*
119      * PnP BIOS
120      *
121      * Allow user override of PnP BIOS search
122      */
123     if ((((p = getenv("machdep.bios.pnp")) == NULL) || strcmp(p, "disable")) &&
124 	((sigaddr = bios_sigsearch(0, "$PnP", 4, 16, 0)) != 0)) {
125 
126 	/* get a virtual pointer to the structure */
127 	pt = (struct PnPBIOS_table *)(uintptr_t)BIOS_PADDRTOVADDR(sigaddr);
128 	for (cv = (u_int8_t *)pt, ck = 0, i = 0; i < pt->len; i++) {
129 	    ck += cv[i];
130 	}
131 	/* If checksum is OK, enable use of the entrypoint */
132 	if (ck == 0) {
133 	    PnPBIOStable = pt;
134 	    if (bootverbose) {
135 		printf("pnpbios: Found PnP BIOS data at %p\n", pt);
136 		printf("pnpbios: Entry = %x:%x  Rev = %d.%d\n",
137 		       pt->pmentrybase, pt->pmentryoffset, pt->version >> 4, pt->version & 0xf);
138 		if ((pt->control & 0x3) == 0x01)
139 		    printf("pnpbios: Event flag at %x\n", pt->evflagaddr);
140 		if (pt->oemdevid != 0)
141 		    printf("pnpbios: OEM ID %x\n", pt->oemdevid);
142 
143 	    }
144 	} else {
145 	    printf("pnpbios: Bad PnP BIOS data checksum\n");
146 	}
147     }
148 
149     if (bootverbose) {
150 	    /* look for other know signatures */
151 	    printf("Other BIOS signatures found:\n");
152 	    printf("ACPI: %08x\n", bios_sigsearch(0, "RSD PTR ", 8, 16, 0));
153     }
154 }
155 
156 /*
157  * bios32_SDlookup
158  *
159  * Query the BIOS32 Service Directory for the service named in (ent),
160  * returns nonzero if the lookup fails.  The caller must fill in
161  * (ent->ident), the remainder are populated on a successful lookup.
162  */
163 int
164 bios32_SDlookup(struct bios32_SDentry *ent)
165 {
166     struct bios_regs args;
167 
168     if (bios32_SDCI == 0)
169 	return (1);
170 
171     args.eax = ent->ident.id;		/* set up arguments */
172     args.ebx = args.ecx = args.edx = 0;
173     bios32(&args, bios32_SDCI, GSEL(GCODE_SEL, SEL_KPL));
174     if ((args.eax & 0xff) == 0) {	/* success? */
175 	ent->base = args.ebx;
176 	ent->len = args.ecx;
177 	ent->entry = args.edx;
178 	ent->ventry = BIOS_PADDRTOVADDR(ent->base + ent->entry);
179 	return (0);			/* all OK */
180     }
181     return (1);				/* failed */
182 }
183 
184 
185 /*
186  * bios_sigsearch
187  *
188  * Search some or all of the BIOS region for a signature string.
189  *
190  * (start)	Optional offset returned from this function
191  *		(for searching for multiple matches), or NULL
192  *		to start the search from the base of the BIOS.
193  *		Note that this will be a _physical_ address in
194  *		the range 0xe0000 - 0xfffff.
195  * (sig)	is a pointer to the byte(s) of the signature.
196  * (siglen)	number of bytes in the signature.
197  * (paralen)	signature paragraph (alignment) size.
198  * (sigofs)	offset of the signature within the paragraph.
199  *
200  * Returns the _physical_ address of the found signature, 0 if the
201  * signature was not found.
202  */
203 
204 u_int32_t
205 bios_sigsearch(u_int32_t start, u_char *sig, int siglen, int paralen, int sigofs)
206 {
207     u_char	*sp, *end;
208 
209     /* compute the starting address */
210     if ((start >= BIOS_START) && (start <= (BIOS_START + BIOS_SIZE))) {
211 	sp = (char *)BIOS_PADDRTOVADDR(start);
212     } else if (start == 0) {
213 	sp = (char *)BIOS_PADDRTOVADDR(BIOS_START);
214     } else {
215 	return 0;				/* bogus start address */
216     }
217 
218     /* compute the end address */
219     end = (u_char *)BIOS_PADDRTOVADDR(BIOS_START + BIOS_SIZE);
220 
221     /* loop searching */
222     while ((sp + sigofs + siglen) < end) {
223 
224 	/* compare here */
225 	if (!bcmp(sp + sigofs, sig, siglen)) {
226 	    /* convert back to physical address */
227 	    return((u_int32_t)BIOS_VADDRTOPADDR(sp));
228 	}
229 	sp += paralen;
230     }
231     return(0);
232 }
233 
234 /*
235  * do not staticize, used by bioscall.s
236  */
237 union {
238     struct {
239 	u_short	offset;
240 	u_short	segment;
241     } vec16;
242     struct {
243 	u_int	offset;
244 	u_short	segment;
245     } vec32;
246 } bioscall_vector;			/* bios jump vector */
247 
248 void
249 set_bios_selectors(struct bios_segments *seg, int flags)
250 {
251     struct soft_segment_descriptor ssd = {
252 	0,			/* segment base address (overwritten) */
253 	0,			/* length (overwritten) */
254 	SDT_MEMERA,		/* segment type (overwritten) */
255 	0,			/* priority level */
256 	1,			/* descriptor present */
257 	0, 0,
258 	1,			/* descriptor size (overwritten) */
259 	0			/* granularity == byte units */
260     };
261     union descriptor *p_gdt;
262 
263 #ifdef SMP
264     p_gdt = &gdt[cpuid * NGDT];
265 #else
266     p_gdt = gdt;
267 #endif
268 
269     ssd.ssd_base = seg->code32.base;
270     ssd.ssd_limit = seg->code32.limit;
271     ssdtosd(&ssd, &p_gdt[GBIOSCODE32_SEL].sd);
272 
273     ssd.ssd_def32 = 0;
274     if (flags & BIOSCODE_FLAG) {
275 	ssd.ssd_base = seg->code16.base;
276 	ssd.ssd_limit = seg->code16.limit;
277 	ssdtosd(&ssd, &p_gdt[GBIOSCODE16_SEL].sd);
278     }
279 
280     ssd.ssd_type = SDT_MEMRWA;
281     if (flags & BIOSDATA_FLAG) {
282 	ssd.ssd_base = seg->data.base;
283 	ssd.ssd_limit = seg->data.limit;
284 	ssdtosd(&ssd, &p_gdt[GBIOSDATA_SEL].sd);
285     }
286 
287     if (flags & BIOSUTIL_FLAG) {
288 	ssd.ssd_base = seg->util.base;
289 	ssd.ssd_limit = seg->util.limit;
290 	ssdtosd(&ssd, &p_gdt[GBIOSUTIL_SEL].sd);
291     }
292 
293     if (flags & BIOSARGS_FLAG) {
294 	ssd.ssd_base = seg->args.base;
295 	ssd.ssd_limit = seg->args.limit;
296 	ssdtosd(&ssd, &p_gdt[GBIOSARGS_SEL].sd);
297     }
298 }
299 
300 extern int vm86pa;
301 extern void bios16_jmp(void);
302 
303 /*
304  * this routine is really greedy with selectors, and uses 5:
305  *
306  * 32-bit code selector:	to return to kernel
307  * 16-bit code selector:	for running code
308  *        data selector:	for 16-bit data
309  *        util selector:	extra utility selector
310  *        args selector:	to handle pointers
311  *
312  * the util selector is set from the util16 entry in bios16_args, if a
313  * "U" specifier is seen.
314  *
315  * See <machine/pc/bios.h> for description of format specifiers
316  */
317 int
318 bios16(struct bios_args *args, char *fmt, ...)
319 {
320     char	*p, *stack, *stack_top;
321     va_list 	ap;
322     int 	flags = BIOSCODE_FLAG | BIOSDATA_FLAG;
323     u_int 	i, arg_start, arg_end;
324     u_int 	*pte, *ptd;
325 
326     arg_start = 0xffffffff;
327     arg_end = 0;
328 
329     /*
330      * Some BIOS entrypoints attempt to copy the largest-case
331      * argument frame (in order to generalise handling for
332      * different entry types).  If our argument frame is
333      * smaller than this, the BIOS will reach off the top of
334      * our constructed stack segment.  Pad the top of the stack
335      * with some garbage to avoid this.
336      */
337     stack = (caddr_t)PAGE_SIZE - 32;
338 
339     va_start(ap, fmt);
340     for (p = fmt; p && *p; p++) {
341 	switch (*p) {
342 	case 'p':			/* 32-bit pointer */
343 	    i = va_arg(ap, u_int);
344 	    arg_start = min(arg_start, i);
345 	    arg_end = max(arg_end, i);
346 	    flags |= BIOSARGS_FLAG;
347 	    stack -= 4;
348 	    break;
349 
350 	case 'i':			/* 32-bit integer */
351 	    i = va_arg(ap, u_int);
352 	    stack -= 4;
353 	    break;
354 
355 	case 'U':			/* 16-bit selector */
356 	    flags |= BIOSUTIL_FLAG;
357 	    /* FALLTHROUGH */
358 	case 'D':			/* 16-bit selector */
359 	case 'C':			/* 16-bit selector */
360 	    stack -= 2;
361 	    break;
362 
363 	case 's':			/* 16-bit integer */
364 	    i = va_arg(ap, u_short);
365 	    stack -= 2;
366 	    break;
367 
368 	default:
369 	    return (EINVAL);
370 	}
371     }
372 
373     if (flags & BIOSARGS_FLAG) {
374 	if (arg_end - arg_start > ctob(16))
375 	    return (EACCES);
376 	args->seg.args.base = arg_start;
377 	args->seg.args.limit = 0xffff;
378     }
379 
380     args->seg.code32.base = (u_int)&bios16_jmp & PG_FRAME;
381     args->seg.code32.limit = 0xffff;
382 
383     ptd = (u_int *)rcr3();
384     if (ptd == IdlePTD) {
385 	/*
386 	 * no page table, so create one and install it.
387 	 */
388 	pte = (u_int *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
389 	ptd = (u_int *)((u_int)ptd + KERNBASE);
390 	*ptd = vtophys(pte) | PG_RW | PG_V;
391     } else {
392 	/*
393 	 * this is a user-level page table
394 	 */
395 	pte = (u_int *)&PTmap;
396     }
397     /*
398      * install pointer to page 0.  we don't need to flush the tlb,
399      * since there should not be a previous mapping for page 0.
400      */
401     *pte = (vm86pa - PAGE_SIZE) | PG_RW | PG_V;
402 
403     stack_top = stack;
404     va_start(ap, fmt);
405     for (p = fmt; p && *p; p++) {
406 	switch (*p) {
407 	case 'p':			/* 32-bit pointer */
408 	    i = va_arg(ap, u_int);
409 	    *(u_int *)stack = (i - arg_start) |
410 		(GSEL(GBIOSARGS_SEL, SEL_KPL) << 16);
411 	    stack += 4;
412 	    break;
413 
414 	case 'i':			/* 32-bit integer */
415 	    i = va_arg(ap, u_int);
416 	    *(u_int *)stack = i;
417 	    stack += 4;
418 	    break;
419 
420 	case 'U':			/* 16-bit selector */
421 	    *(u_short *)stack = GSEL(GBIOSUTIL_SEL, SEL_KPL);
422 	    stack += 2;
423 	    break;
424 
425 	case 'D':			/* 16-bit selector */
426 	    *(u_short *)stack = GSEL(GBIOSDATA_SEL, SEL_KPL);
427 	    stack += 2;
428 	    break;
429 
430 	case 'C':			/* 16-bit selector */
431 	    *(u_short *)stack = GSEL(GBIOSCODE16_SEL, SEL_KPL);
432 	    stack += 2;
433 	    break;
434 
435 	case 's':			/* 16-bit integer */
436 	    i = va_arg(ap, u_short);
437 	    *(u_short *)stack = i;
438 	    stack += 2;
439 	    break;
440 
441 	default:
442 	    return (EINVAL);
443 	}
444     }
445 
446     set_bios_selectors(&args->seg, flags);
447     bioscall_vector.vec16.offset = (u_short)args->entry;
448     bioscall_vector.vec16.segment = GSEL(GBIOSCODE16_SEL, SEL_KPL);
449 
450     i = bios16_call(&args->r, stack_top);
451 
452     if (pte == (u_int *)&PTmap) {
453 	*pte = 0;			/* remove entry */
454     } else {
455 	*ptd = 0;			/* remove page table */
456 	free(pte, M_TEMP);		/* ... and free it */
457     }
458 
459     /*
460      * XXX only needs to be invlpg(0) but that doesn't work on the 386
461      */
462     invltlb();
463 
464     return (i);
465 }
466 
467 /*
468  * PnP BIOS interface; enumerate devices only known to the system
469  * BIOS and save information about them for later use.
470  */
471 
472 struct pnp_sysdev
473 {
474     u_int16_t	size;
475     u_int8_t	handle;
476     u_int32_t	devid;
477     u_int8_t	type[3];
478     u_int16_t	attrib;
479 #define PNPATTR_NODISABLE	(1<<0)	/* can't be disabled */
480 #define PNPATTR_NOCONFIG	(1<<1)	/* can't be configured */
481 #define PNPATTR_OUTPUT		(1<<2)	/* can be primary output */
482 #define PNPATTR_INPUT		(1<<3)	/* can be primary input */
483 #define PNPATTR_BOOTABLE	(1<<4)	/* can be booted from */
484 #define PNPATTR_DOCK		(1<<5)	/* is a docking station */
485 #define PNPATTR_REMOVEABLE	(1<<6)	/* device is removeable */
486 #define PNPATTR_CONFIG_STATIC	0x00
487 #define PNPATTR_CONFIG_DYNAMIC	0x07
488 #define PNPATTR_CONFIG_DYNONLY	0x17
489     /* device-specific data comes here */
490     u_int8_t	devdata[0];
491 } __attribute__ ((packed));
492 
493 /* We have to cluster arguments within a 64k range for the bios16 call */
494 struct pnp_sysdevargs
495 {
496     u_int16_t	next;
497     struct pnp_sysdev node;
498 };
499 
500 /*
501  * This function is called after the bus has assigned resource
502  * locations for a logical device.
503  */
504 static void
505 pnpbios_set_config(void *arg, struct isa_config *config, int enable)
506 {
507 }
508 
509 /*
510  * Quiz the PnP BIOS, build a list of PNP IDs and resource data.
511  */
512 static void
513 pnpbios_identify(driver_t *driver, device_t parent)
514 {
515     struct PnPBIOS_table	*pt = PnPBIOStable;
516     struct bios_args		args;
517     struct pnp_sysdev		*pd;
518     struct pnp_sysdevargs	*pda;
519     u_int16_t			ndevs, bigdev;
520     int				error, currdev;
521     u_int8_t			*devnodebuf, tag;
522     u_int32_t			*devid, *compid;
523     int				idx, left;
524     device_t			dev;
525 
526     /* no PnP BIOS information */
527     if (pt == NULL)
528 	return;
529 
530     bzero(&args, sizeof(args));
531     args.seg.code16.base = BIOS_PADDRTOVADDR(pt->pmentrybase);
532     args.seg.code16.limit = 0xffff;		/* XXX ? */
533     args.seg.data.base = BIOS_PADDRTOVADDR(pt->pmdataseg);
534     args.seg.data.limit = 0xffff;
535     args.entry = pt->pmentryoffset;
536 
537     if ((error = bios16(&args, PNP_COUNT_DEVNODES, &ndevs, &bigdev)) || (args.r.eax & 0xff))
538 	printf("pnpbios: error %d/%x getting device count/size limit\n", error, args.r.eax);
539     ndevs &= 0xff;				/* clear high byte garbage */
540     if (bootverbose)
541 	printf("pnpbios: %d devices, largest %d bytes\n", ndevs, bigdev);
542 
543     devnodebuf = malloc(bigdev + (sizeof(struct pnp_sysdevargs) - sizeof(struct pnp_sysdev)),
544 			M_DEVBUF, M_NOWAIT);
545     pda = (struct pnp_sysdevargs *)devnodebuf;
546     pd = &pda->node;
547 
548     for (currdev = 0, left = ndevs; (currdev != 0xff) && (left > 0); left--) {
549 
550 	bzero(pd, bigdev);
551 	pda->next = currdev;
552 	/* get current configuration */
553 	if ((error = bios16(&args, PNP_GET_DEVNODE, &pda->next, &pda->node, (u_int16_t)1))) {
554 	    printf("pnpbios: error %d making BIOS16 call\n", error);
555 	    break;
556 	}
557 	if ((error = (args.r.eax & 0xff))) {
558 	    if (bootverbose)
559 		printf("pnpbios: %s 0x%x fetching node %d\n", error & 0x80 ? "error" : "warning", error, currdev);
560 	    if (error & 0x80)
561 		break;
562 	}
563 	currdev = pda->next;
564 	if (pd->size < sizeof(struct pnp_sysdev)) {
565 	    printf("pnpbios: bogus system node data, aborting scan\n");
566 	    break;
567 	}
568 
569 	/*
570 	 * If we are in APIC_IO mode, we should ignore the ISA PIC if it
571 	 * shows up.  Likewise, in !APIC_IO mode, we should ignore the
572 	 * APIC (less important).
573 	 * This is significant because the ISA PIC will claim IRQ 2 (which
574 	 * it uses for chaining), while in APIC mode this is a valid IRQ
575 	 * available for general use.
576 	 */
577 #ifdef APIC_IO
578 	if (!strcmp(pnp_eisaformat(pd->devid), "PNP0000"))	/* ISA PIC */
579 	    continue;
580 #else
581 	if (!strcmp(pnp_eisaformat(pd->devid), "PNP0003"))	/* APIC */
582 	    continue;
583 #endif
584 
585 	/* Add the device and parse its resources */
586 	dev = BUS_ADD_CHILD(parent, ISA_ORDER_PNP, NULL, -1);
587 	isa_set_vendorid(dev, pd->devid);
588 	isa_set_logicalid(dev, pd->devid);
589 	ISA_SET_CONFIG_CALLBACK(parent, dev, pnpbios_set_config, 0);
590 	pnp_parse_resources(dev, &pd->devdata[0],
591 			    pd->size - sizeof(struct pnp_sysdev),
592 			    isa_get_vendorid(dev), isa_get_logicalid(dev), 0);
593 	if (!device_get_desc(dev))
594 	    device_set_desc_copy(dev, pnp_eisaformat(pd->devid));
595 
596 	/* Find device IDs */
597 	devid = &pd->devid;
598 	compid = NULL;
599 
600 	/* look for a compatible device ID too */
601 	left = pd->size - sizeof(struct pnp_sysdev);
602 	idx = 0;
603 	while (idx < left) {
604 	    tag = pd->devdata[idx++];
605 	    if (PNP_RES_TYPE(tag) == 0) {
606 		/* Small resource */
607 		switch (PNP_SRES_NUM(tag)) {
608 		case PNP_TAG_COMPAT_DEVICE:
609 		    compid = (u_int32_t *)(pd->devdata + idx);
610 		    if (bootverbose)
611 			printf("pnpbios: node %d compat ID 0x%08x\n", pd->handle, *compid);
612 		    /* FALLTHROUGH */
613 		case PNP_TAG_END:
614 		    idx = left;
615 		    break;
616 		default:
617 		    idx += PNP_SRES_LEN(tag);
618 		    break;
619 		}
620 	    } else
621 		/* Large resource, skip it */
622 		idx += *(u_int16_t *)(pd->devdata + idx) + 2;
623 	}
624 	if (bootverbose) {
625 	    printf("pnpbios: handle %d device ID %s (%08x)",
626 		   pd->handle, pnp_eisaformat(*devid), *devid);
627 	    if (compid != NULL)
628 		printf(" compat ID %s (%08x)",
629 		       pnp_eisaformat(*compid), *compid);
630 	    printf("\n");
631 	}
632     }
633 }
634 
635 static device_method_t pnpbios_methods[] = {
636 	/* Device interface */
637 	DEVMETHOD(device_identify,	pnpbios_identify),
638 
639 	{ 0, 0 }
640 };
641 
642 static driver_t pnpbios_driver = {
643 	"pnpbios",
644 	pnpbios_methods,
645 	1,			/* no softc */
646 };
647 
648 static devclass_t pnpbios_devclass;
649 
650 DRIVER_MODULE(pnpbios, isa, pnpbios_driver, pnpbios_devclass, 0, 0);
651