bios.c revision 130641 
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
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD: head/sys/amd64/amd64/bios.c 130641 2004-06-17 17:27:37Z njl $");
30
31/*
32 * Code for dealing with the BIOS in x86 PC systems.
33 */
34
35#include "opt_isa.h"
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/kernel.h>
40#include <sys/malloc.h>
41#include <sys/module.h>
42#include <sys/bus.h>
43#include <sys/pcpu.h>
44#include <vm/vm.h>
45#include <vm/pmap.h>
46#include <machine/md_var.h>
47#include <machine/segments.h>
48#include <machine/stdarg.h>
49#include <machine/vmparam.h>
50#include <machine/pc/bios.h>
51#ifdef DEV_ISA
52#include <isa/isavar.h>
53#include <isa/pnpreg.h>
54#include <isa/pnpvar.h>
55#endif
56
57#define BIOS_START	0xe0000
58#define BIOS_SIZE	0x20000
59
60/* exported lookup results */
61struct bios32_SDentry		PCIbios;
62
63static struct PnPBIOS_table	*PnPBIOStable;
64
65static u_int			bios32_SDCI;
66
67/* start fairly early */
68static void			bios32_init(void *junk);
69SYSINIT(bios32, SI_SUB_CPU, SI_ORDER_ANY, bios32_init, NULL);
70
71/*
72 * bios32_init
73 *
74 * Locate various bios32 entities.
75 */
76static void
77bios32_init(void *junk)
78{
79    u_long			sigaddr;
80    struct bios32_SDheader	*sdh;
81    struct PnPBIOS_table	*pt;
82    u_int8_t			ck, *cv;
83    int				i;
84    char			*p;
85
86    /*
87     * BIOS32 Service Directory, PCI BIOS
88     */
89
90    /* look for the signature */
91    if ((sigaddr = bios_sigsearch(0, "_32_", 4, 16, 0)) != 0) {
92
93	/* get a virtual pointer to the structure */
94	sdh = (struct bios32_SDheader *)(uintptr_t)BIOS_PADDRTOVADDR(sigaddr);
95	for (cv = (u_int8_t *)sdh, ck = 0, i = 0; i < (sdh->len * 16); i++) {
96	    ck += cv[i];
97	}
98	/* If checksum is OK, enable use of the entrypoint */
99	if ((ck == 0) && (BIOS_START <= sdh->entry ) &&
100	    (sdh->entry < (BIOS_START + BIOS_SIZE))) {
101	    bios32_SDCI = BIOS_PADDRTOVADDR(sdh->entry);
102	    if (bootverbose) {
103		printf("bios32: Found BIOS32 Service Directory header at %p\n", sdh);
104		printf("bios32: Entry = 0x%x (%x)  Rev = %d  Len = %d\n",
105		       sdh->entry, bios32_SDCI, sdh->revision, sdh->len);
106	    }
107
108	    /* Allow user override of PCI BIOS search */
109	    if (((p = getenv("machdep.bios.pci")) == NULL) || strcmp(p, "disable")) {
110
111		/* See if there's a PCI BIOS entrypoint here */
112		PCIbios.ident.id = 0x49435024;	/* PCI systems should have this */
113		if (!bios32_SDlookup(&PCIbios) && bootverbose)
114		    printf("pcibios: PCI BIOS entry at 0x%x+0x%x\n", PCIbios.base, PCIbios.entry);
115	    }
116	    if (p != NULL)
117		    freeenv(p);
118	} else {
119	    printf("bios32: Bad BIOS32 Service Directory\n");
120	}
121    }
122
123    /*
124     * PnP BIOS
125     *
126     * Allow user override of PnP BIOS search
127     */
128    if ((((p = getenv("machdep.bios.pnp")) == NULL) || strcmp(p, "disable")) &&
129	((sigaddr = bios_sigsearch(0, "$PnP", 4, 16, 0)) != 0)) {
130
131	/* get a virtual pointer to the structure */
132	pt = (struct PnPBIOS_table *)(uintptr_t)BIOS_PADDRTOVADDR(sigaddr);
133	for (cv = (u_int8_t *)pt, ck = 0, i = 0; i < pt->len; i++) {
134	    ck += cv[i];
135	}
136	/* If checksum is OK, enable use of the entrypoint */
137	if (ck == 0) {
138	    PnPBIOStable = pt;
139	    if (bootverbose) {
140		printf("pnpbios: Found PnP BIOS data at %p\n", pt);
141		printf("pnpbios: Entry = %x:%x  Rev = %d.%d\n",
142		       pt->pmentrybase, pt->pmentryoffset, pt->version >> 4, pt->version & 0xf);
143		if ((pt->control & 0x3) == 0x01)
144		    printf("pnpbios: Event flag at %x\n", pt->evflagaddr);
145		if (pt->oemdevid != 0)
146		    printf("pnpbios: OEM ID %x\n", pt->oemdevid);
147
148	    }
149	} else {
150	    printf("pnpbios: Bad PnP BIOS data checksum\n");
151	}
152    }
153    if (p != NULL)
154	    freeenv(p);
155    if (bootverbose) {
156	    /* look for other know signatures */
157	    printf("Other BIOS signatures found:\n");
158    }
159}
160
161/*
162 * bios32_SDlookup
163 *
164 * Query the BIOS32 Service Directory for the service named in (ent),
165 * returns nonzero if the lookup fails.  The caller must fill in
166 * (ent->ident), the remainder are populated on a successful lookup.
167 */
168int
169bios32_SDlookup(struct bios32_SDentry *ent)
170{
171    struct bios_regs args;
172
173    if (bios32_SDCI == 0)
174	return (1);
175
176    args.eax = ent->ident.id;		/* set up arguments */
177    args.ebx = args.ecx = args.edx = 0;
178    bios32(&args, bios32_SDCI, GSEL(GCODE_SEL, SEL_KPL));
179    if ((args.eax & 0xff) == 0) {	/* success? */
180	ent->base = args.ebx;
181	ent->len = args.ecx;
182	ent->entry = args.edx;
183	ent->ventry = BIOS_PADDRTOVADDR(ent->base + ent->entry);
184	return (0);			/* all OK */
185    }
186    return (1);				/* failed */
187}
188
189
190/*
191 * bios_sigsearch
192 *
193 * Search some or all of the BIOS region for a signature string.
194 *
195 * (start)	Optional offset returned from this function
196 *		(for searching for multiple matches), or NULL
197 *		to start the search from the base of the BIOS.
198 *		Note that this will be a _physical_ address in
199 *		the range 0xe0000 - 0xfffff.
200 * (sig)	is a pointer to the byte(s) of the signature.
201 * (siglen)	number of bytes in the signature.
202 * (paralen)	signature paragraph (alignment) size.
203 * (sigofs)	offset of the signature within the paragraph.
204 *
205 * Returns the _physical_ address of the found signature, 0 if the
206 * signature was not found.
207 */
208
209u_int32_t
210bios_sigsearch(u_int32_t start, u_char *sig, int siglen, int paralen, int sigofs)
211{
212    u_char	*sp, *end;
213
214    /* compute the starting address */
215    if ((start >= BIOS_START) && (start <= (BIOS_START + BIOS_SIZE))) {
216	sp = (char *)BIOS_PADDRTOVADDR(start);
217    } else if (start == 0) {
218	sp = (char *)BIOS_PADDRTOVADDR(BIOS_START);
219    } else {
220	return 0;				/* bogus start address */
221    }
222
223    /* compute the end address */
224    end = (u_char *)BIOS_PADDRTOVADDR(BIOS_START + BIOS_SIZE);
225
226    /* loop searching */
227    while ((sp + sigofs + siglen) < end) {
228
229	/* compare here */
230	if (!bcmp(sp + sigofs, sig, siglen)) {
231	    /* convert back to physical address */
232	    return((u_int32_t)BIOS_VADDRTOPADDR(sp));
233	}
234	sp += paralen;
235    }
236    return(0);
237}
238
239/*
240 * do not staticize, used by bioscall.s
241 */
242union {
243    struct {
244	u_short	offset;
245	u_short	segment;
246    } vec16;
247    struct {
248	u_int	offset;
249	u_short	segment;
250    } vec32;
251} bioscall_vector;			/* bios jump vector */
252
253void
254set_bios_selectors(struct bios_segments *seg, int flags)
255{
256    struct soft_segment_descriptor ssd = {
257	0,			/* segment base address (overwritten) */
258	0,			/* length (overwritten) */
259	SDT_MEMERA,		/* segment type (overwritten) */
260	0,			/* priority level */
261	1,			/* descriptor present */
262	0, 0,
263	1,			/* descriptor size (overwritten) */
264	0			/* granularity == byte units */
265    };
266    union descriptor *p_gdt;
267
268#ifdef SMP
269    p_gdt = &gdt[PCPU_GET(cpuid) * NGDT];
270#else
271    p_gdt = gdt;
272#endif
273
274    ssd.ssd_base = seg->code32.base;
275    ssd.ssd_limit = seg->code32.limit;
276    ssdtosd(&ssd, &p_gdt[GBIOSCODE32_SEL].sd);
277
278    ssd.ssd_def32 = 0;
279    if (flags & BIOSCODE_FLAG) {
280	ssd.ssd_base = seg->code16.base;
281	ssd.ssd_limit = seg->code16.limit;
282	ssdtosd(&ssd, &p_gdt[GBIOSCODE16_SEL].sd);
283    }
284
285    ssd.ssd_type = SDT_MEMRWA;
286    if (flags & BIOSDATA_FLAG) {
287	ssd.ssd_base = seg->data.base;
288	ssd.ssd_limit = seg->data.limit;
289	ssdtosd(&ssd, &p_gdt[GBIOSDATA_SEL].sd);
290    }
291
292    if (flags & BIOSUTIL_FLAG) {
293	ssd.ssd_base = seg->util.base;
294	ssd.ssd_limit = seg->util.limit;
295	ssdtosd(&ssd, &p_gdt[GBIOSUTIL_SEL].sd);
296    }
297
298    if (flags & BIOSARGS_FLAG) {
299	ssd.ssd_base = seg->args.base;
300	ssd.ssd_limit = seg->args.limit;
301	ssdtosd(&ssd, &p_gdt[GBIOSARGS_SEL].sd);
302    }
303}
304
305extern int vm86pa;
306extern void bios16_jmp(void);
307
308/*
309 * this routine is really greedy with selectors, and uses 5:
310 *
311 * 32-bit code selector:	to return to kernel
312 * 16-bit code selector:	for running code
313 *        data selector:	for 16-bit data
314 *        util selector:	extra utility selector
315 *        args selector:	to handle pointers
316 *
317 * the util selector is set from the util16 entry in bios16_args, if a
318 * "U" specifier is seen.
319 *
320 * See <machine/pc/bios.h> for description of format specifiers
321 */
322int
323bios16(struct bios_args *args, char *fmt, ...)
324{
325    char	*p, *stack, *stack_top;
326    va_list 	ap;
327    int 	flags = BIOSCODE_FLAG | BIOSDATA_FLAG;
328    u_int 	i, arg_start, arg_end;
329    pt_entry_t	*pte;
330    pd_entry_t	*ptd;
331
332    arg_start = 0xffffffff;
333    arg_end = 0;
334
335    /*
336     * Some BIOS entrypoints attempt to copy the largest-case
337     * argument frame (in order to generalise handling for
338     * different entry types).  If our argument frame is
339     * smaller than this, the BIOS will reach off the top of
340     * our constructed stack segment.  Pad the top of the stack
341     * with some garbage to avoid this.
342     */
343    stack = (caddr_t)PAGE_SIZE - 32;
344
345    va_start(ap, fmt);
346    for (p = fmt; p && *p; p++) {
347	switch (*p) {
348	case 'p':			/* 32-bit pointer */
349	    i = va_arg(ap, u_int);
350	    arg_start = min(arg_start, i);
351	    arg_end = max(arg_end, i);
352	    flags |= BIOSARGS_FLAG;
353	    stack -= 4;
354	    break;
355
356	case 'i':			/* 32-bit integer */
357	    i = va_arg(ap, u_int);
358	    stack -= 4;
359	    break;
360
361	case 'U':			/* 16-bit selector */
362	    flags |= BIOSUTIL_FLAG;
363	    /* FALLTHROUGH */
364	case 'D':			/* 16-bit selector */
365	case 'C':			/* 16-bit selector */
366	    stack -= 2;
367	    break;
368
369	case 's':			/* 16-bit integer passed as an int */
370	    i = va_arg(ap, int);
371	    stack -= 2;
372	    break;
373
374	default:
375	    return (EINVAL);
376	}
377    }
378
379    if (flags & BIOSARGS_FLAG) {
380	if (arg_end - arg_start > ctob(16))
381	    return (EACCES);
382	args->seg.args.base = arg_start;
383	args->seg.args.limit = 0xffff;
384    }
385
386    args->seg.code32.base = (u_int)&bios16_jmp & PG_FRAME;
387    args->seg.code32.limit = 0xffff;
388
389    ptd = (pd_entry_t *)rcr3();
390#ifdef PAE
391    if (ptd == IdlePDPT)
392#else
393    if (ptd == IdlePTD)
394#endif
395    {
396	/*
397	 * no page table, so create one and install it.
398	 */
399	pte = (pt_entry_t *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
400	ptd = (pd_entry_t *)((u_int)IdlePTD + KERNBASE);
401	*pte = (vm86pa - PAGE_SIZE) | PG_RW | PG_V;
402	*ptd = vtophys(pte) | PG_RW | PG_V;
403    } else {
404	/*
405	 * this is a user-level page table
406	 */
407	pte = PTmap;
408	*pte = (vm86pa - PAGE_SIZE) | PG_RW | PG_V;
409    }
410    pmap_invalidate_all(kernel_pmap);	/* XXX insurance for now */
411
412    stack_top = stack;
413    va_start(ap, fmt);
414    for (p = fmt; p && *p; p++) {
415	switch (*p) {
416	case 'p':			/* 32-bit pointer */
417	    i = va_arg(ap, u_int);
418	    *(u_int *)stack = (i - arg_start) |
419		(GSEL(GBIOSARGS_SEL, SEL_KPL) << 16);
420	    stack += 4;
421	    break;
422
423	case 'i':			/* 32-bit integer */
424	    i = va_arg(ap, u_int);
425	    *(u_int *)stack = i;
426	    stack += 4;
427	    break;
428
429	case 'U':			/* 16-bit selector */
430	    *(u_short *)stack = GSEL(GBIOSUTIL_SEL, SEL_KPL);
431	    stack += 2;
432	    break;
433
434	case 'D':			/* 16-bit selector */
435	    *(u_short *)stack = GSEL(GBIOSDATA_SEL, SEL_KPL);
436	    stack += 2;
437	    break;
438
439	case 'C':			/* 16-bit selector */
440	    *(u_short *)stack = GSEL(GBIOSCODE16_SEL, SEL_KPL);
441	    stack += 2;
442	    break;
443
444	case 's':			/* 16-bit integer passed as an int */
445	    i = va_arg(ap, int);
446	    *(u_short *)stack = i;
447	    stack += 2;
448	    break;
449
450	default:
451	    return (EINVAL);
452	}
453    }
454
455    set_bios_selectors(&args->seg, flags);
456    bioscall_vector.vec16.offset = (u_short)args->entry;
457    bioscall_vector.vec16.segment = GSEL(GBIOSCODE16_SEL, SEL_KPL);
458
459    i = bios16_call(&args->r, stack_top);
460
461    if (pte == PTmap) {
462	*pte = 0;			/* remove entry */
463	/*
464	 * XXX only needs to be invlpg(0) but that doesn't work on the 386
465	 */
466	pmap_invalidate_all(kernel_pmap);
467    } else {
468	*ptd = 0;			/* remove page table */
469	/*
470	 * XXX only needs to be invlpg(0) but that doesn't work on the 386
471	 */
472	pmap_invalidate_all(kernel_pmap);
473	free(pte, M_TEMP);		/* ... and free it */
474    }
475    return (i);
476}
477
478const u_char *
479bios_string(u_int from, u_int to, const u_char *string, int len)
480{
481	const char *t, *te;
482
483	if (len == 0)
484		len = strlen(string);
485	t = (const char *)(KERNBASE + from);
486	te = (const char *)(KERNBASE + to);
487	for (; t <= te; t++)
488		if (!memcmp(string, t, len))
489			return (t);
490	return (NULL);
491}
492
493#ifdef DEV_ISA
494/*
495 * PnP BIOS interface; enumerate devices only known to the system
496 * BIOS and save information about them for later use.
497 */
498
499struct pnp_sysdev
500{
501    u_int16_t	size;
502    u_int8_t	handle;
503    u_int32_t	devid;
504    u_int8_t	type[3];
505    u_int16_t	attrib;
506#define PNPATTR_NODISABLE	(1<<0)	/* can't be disabled */
507#define PNPATTR_NOCONFIG	(1<<1)	/* can't be configured */
508#define PNPATTR_OUTPUT		(1<<2)	/* can be primary output */
509#define PNPATTR_INPUT		(1<<3)	/* can be primary input */
510#define PNPATTR_BOOTABLE	(1<<4)	/* can be booted from */
511#define PNPATTR_DOCK		(1<<5)	/* is a docking station */
512#define PNPATTR_REMOVEABLE	(1<<6)	/* device is removeable */
513#define PNPATTR_CONFIG_STATIC	(0)
514#define PNPATTR_CONFIG_DYNAMIC	(1)
515#define PNPATTR_CONFIG_DYNONLY	(3)
516#define PNPATTR_CONFIG(a)	(((a) >> 7) & 0x3)
517    /* device-specific data comes here */
518    u_int8_t	devdata[0];
519} __packed;
520
521/* We have to cluster arguments within a 64k range for the bios16 call */
522struct pnp_sysdevargs
523{
524    u_int16_t	next;
525    struct pnp_sysdev node;
526};
527
528/*
529 * This function is called after the bus has assigned resource
530 * locations for a logical device.
531 */
532static void
533pnpbios_set_config(void *arg, struct isa_config *config, int enable)
534{
535}
536
537/*
538 * Quiz the PnP BIOS, build a list of PNP IDs and resource data.
539 */
540static void
541pnpbios_identify(driver_t *driver, device_t parent)
542{
543    struct PnPBIOS_table	*pt = PnPBIOStable;
544    struct bios_args		args;
545    struct pnp_sysdev		*pd;
546    struct pnp_sysdevargs	*pda;
547    u_int16_t			ndevs, bigdev;
548    int				error, currdev;
549    u_int8_t			*devnodebuf, tag;
550    u_int32_t			*devid, *compid;
551    int				idx, left;
552    device_t			dev;
553
554    /* no PnP BIOS information */
555    if (pt == NULL)
556	return;
557
558    /* ACPI already active */
559    if (devclass_get_softc(devclass_find("acpi"), 0) != NULL)
560	return;
561
562    /* get count of PnP devices */
563    bzero(&args, sizeof(args));
564    args.seg.code16.base = BIOS_PADDRTOVADDR(pt->pmentrybase);
565    args.seg.code16.limit = 0xffff;		/* XXX ? */
566    args.seg.data.base = BIOS_PADDRTOVADDR(pt->pmdataseg);
567    args.seg.data.limit = 0xffff;
568    args.entry = pt->pmentryoffset;
569
570    if ((error = bios16(&args, PNP_COUNT_DEVNODES, &ndevs, &bigdev)) || (args.r.eax & 0xff))
571	printf("pnpbios: error %d/%x getting device count/size limit\n", error, args.r.eax);
572    ndevs &= 0xff;				/* clear high byte garbage */
573    if (bootverbose)
574	printf("pnpbios: %d devices, largest %d bytes\n", ndevs, bigdev);
575
576    devnodebuf = malloc(bigdev + (sizeof(struct pnp_sysdevargs) - sizeof(struct pnp_sysdev)),
577			M_DEVBUF, M_NOWAIT);
578    pda = (struct pnp_sysdevargs *)devnodebuf;
579    pd = &pda->node;
580
581    for (currdev = 0, left = ndevs; (currdev != 0xff) && (left > 0); left--) {
582
583	bzero(pd, bigdev);
584	pda->next = currdev;
585	/* get current configuration */
586	if ((error = bios16(&args, PNP_GET_DEVNODE, &pda->next, &pda->node, 1))) {
587	    printf("pnpbios: error %d making BIOS16 call\n", error);
588	    break;
589	}
590	if ((error = (args.r.eax & 0xff))) {
591	    if (bootverbose)
592		printf("pnpbios: %s 0x%x fetching node %d\n", error & 0x80 ? "error" : "warning", error, currdev);
593	    if (error & 0x80)
594		break;
595	}
596	currdev = pda->next;
597	if (pd->size < sizeof(struct pnp_sysdev)) {
598	    printf("pnpbios: bogus system node data, aborting scan\n");
599	    break;
600	}
601
602	/*
603	 * Ignore PICs so that we don't have to worry about the PICs
604	 * claiming IRQs to prevent their use.  The PIC drivers
605	 * already ensure that invalid IRQs are not used.
606	 */
607	if (!strcmp(pnp_eisaformat(pd->devid), "PNP0000"))	/* ISA PIC */
608	    continue;
609	if (!strcmp(pnp_eisaformat(pd->devid), "PNP0003"))	/* APIC */
610	    continue;
611
612	/* Add the device and parse its resources */
613	dev = BUS_ADD_CHILD(parent, ISA_ORDER_PNP, NULL, -1);
614	isa_set_vendorid(dev, pd->devid);
615	isa_set_logicalid(dev, pd->devid);
616	/*
617	 * It appears that some PnP BIOS doesn't allow us to re-enable
618	 * the embedded system device once it is disabled.  We shall
619	 * mark all system device nodes as "cannot be disabled", regardless
620	 * of actual settings in the device attribute byte.
621	 * XXX
622	isa_set_configattr(dev,
623	    ((pd->attrib & PNPATTR_NODISABLE) ?  0 : ISACFGATTR_CANDISABLE) |
624	    ((!(pd->attrib & PNPATTR_NOCONFIG) &&
625		PNPATTR_CONFIG(pd->attrib) != PNPATTR_CONFIG_STATIC)
626		? ISACFGATTR_DYNAMIC : 0));
627	 */
628	isa_set_configattr(dev,
629	    (!(pd->attrib & PNPATTR_NOCONFIG) &&
630		PNPATTR_CONFIG(pd->attrib) != PNPATTR_CONFIG_STATIC)
631		? ISACFGATTR_DYNAMIC : 0);
632	ISA_SET_CONFIG_CALLBACK(parent, dev, pnpbios_set_config, 0);
633	pnp_parse_resources(dev, &pd->devdata[0],
634			    pd->size - sizeof(struct pnp_sysdev), 0);
635	if (!device_get_desc(dev))
636	    device_set_desc_copy(dev, pnp_eisaformat(pd->devid));
637
638	/* Find device IDs */
639	devid = &pd->devid;
640	compid = NULL;
641
642	/* look for a compatible device ID too */
643	left = pd->size - sizeof(struct pnp_sysdev);
644	idx = 0;
645	while (idx < left) {
646	    tag = pd->devdata[idx++];
647	    if (PNP_RES_TYPE(tag) == 0) {
648		/* Small resource */
649		switch (PNP_SRES_NUM(tag)) {
650		case PNP_TAG_COMPAT_DEVICE:
651		    compid = (u_int32_t *)(pd->devdata + idx);
652		    if (bootverbose)
653			printf("pnpbios: node %d compat ID 0x%08x\n", pd->handle, *compid);
654		    /* FALLTHROUGH */
655		case PNP_TAG_END:
656		    idx = left;
657		    break;
658		default:
659		    idx += PNP_SRES_LEN(tag);
660		    break;
661		}
662	    } else
663		/* Large resource, skip it */
664		idx += *(u_int16_t *)(pd->devdata + idx) + 2;
665	}
666	if (bootverbose) {
667	    printf("pnpbios: handle %d device ID %s (%08x)",
668		   pd->handle, pnp_eisaformat(*devid), *devid);
669	    if (compid != NULL)
670		printf(" compat ID %s (%08x)",
671		       pnp_eisaformat(*compid), *compid);
672	    printf("\n");
673	}
674    }
675}
676
677static device_method_t pnpbios_methods[] = {
678	/* Device interface */
679	DEVMETHOD(device_identify,	pnpbios_identify),
680
681	{ 0, 0 }
682};
683
684static driver_t pnpbios_driver = {
685	"pnpbios",
686	pnpbios_methods,
687	1,			/* no softc */
688};
689
690static devclass_t pnpbios_devclass;
691
692DRIVER_MODULE(pnpbios, isa, pnpbios_driver, pnpbios_devclass, 0, 0);
693#endif /* DEV_ISA */
694