bios.c revision 282065
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: stable/10/sys/i386/i386/bios.c 282065 2015-04-27 08:02:12Z kib $");
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	    va_end(ap);
376	    return (EINVAL);
377	}
378    }
379    va_end(ap);
380
381    if (flags & BIOSARGS_FLAG) {
382	if (arg_end - arg_start > ctob(16))
383	    return (EACCES);
384	args->seg.args.base = arg_start;
385	args->seg.args.limit = 0xffff;
386    }
387
388    args->seg.code32.base = (u_int)&bios16_jmp & PG_FRAME;
389    args->seg.code32.limit = 0xffff;
390
391    ptd = (pd_entry_t *)rcr3();
392#if defined(PAE) || defined(PAE_TABLES)
393    if (ptd == IdlePDPT)
394#else
395    if (ptd == IdlePTD)
396#endif
397    {
398	/*
399	 * no page table, so create one and install it.
400	 */
401	pte = (pt_entry_t *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
402	ptd = (pd_entry_t *)((u_int)IdlePTD + KERNBASE);
403	*pte = (vm86pa - PAGE_SIZE) | PG_RW | PG_V;
404	*ptd = vtophys(pte) | PG_RW | PG_V;
405    } else {
406	/*
407	 * this is a user-level page table
408	 */
409	pte = PTmap;
410	*pte = (vm86pa - PAGE_SIZE) | PG_RW | PG_V;
411    }
412    pmap_invalidate_all(kernel_pmap);	/* XXX insurance for now */
413
414    stack_top = stack;
415    va_start(ap, fmt);
416    for (p = fmt; p && *p; p++) {
417	switch (*p) {
418	case 'p':			/* 32-bit pointer */
419	    i = va_arg(ap, u_int);
420	    *(u_int *)stack = (i - arg_start) |
421		(GSEL(GBIOSARGS_SEL, SEL_KPL) << 16);
422	    stack += 4;
423	    break;
424
425	case 'i':			/* 32-bit integer */
426	    i = va_arg(ap, u_int);
427	    *(u_int *)stack = i;
428	    stack += 4;
429	    break;
430
431	case 'U':			/* 16-bit selector */
432	    *(u_short *)stack = GSEL(GBIOSUTIL_SEL, SEL_KPL);
433	    stack += 2;
434	    break;
435
436	case 'D':			/* 16-bit selector */
437	    *(u_short *)stack = GSEL(GBIOSDATA_SEL, SEL_KPL);
438	    stack += 2;
439	    break;
440
441	case 'C':			/* 16-bit selector */
442	    *(u_short *)stack = GSEL(GBIOSCODE16_SEL, SEL_KPL);
443	    stack += 2;
444	    break;
445
446	case 's':			/* 16-bit integer passed as an int */
447	    i = va_arg(ap, int);
448	    *(u_short *)stack = i;
449	    stack += 2;
450	    break;
451
452	default:
453	    va_end(ap);
454	    return (EINVAL);
455	}
456    }
457    va_end(ap);
458
459    set_bios_selectors(&args->seg, flags);
460    bioscall_vector.vec16.offset = (u_short)args->entry;
461    bioscall_vector.vec16.segment = GSEL(GBIOSCODE16_SEL, SEL_KPL);
462
463    i = bios16_call(&args->r, stack_top);
464
465    if (pte == PTmap) {
466	*pte = 0;			/* remove entry */
467	/*
468	 * XXX only needs to be invlpg(0) but that doesn't work on the 386
469	 */
470	pmap_invalidate_all(kernel_pmap);
471    } else {
472	*ptd = 0;			/* remove page table */
473	/*
474	 * XXX only needs to be invlpg(0) but that doesn't work on the 386
475	 */
476	pmap_invalidate_all(kernel_pmap);
477	free(pte, M_TEMP);		/* ... and free it */
478    }
479    return (i);
480}
481
482int
483bios_oem_strings(struct bios_oem *oem, u_char *buffer, size_t maxlen)
484{
485	size_t idx = 0;
486	struct bios_oem_signature *sig;
487	u_int from, to;
488	u_char c, *s, *se, *str, *bios_str;
489	size_t i, off, len, tot;
490
491	if ( !oem || !buffer || maxlen<2 )
492		return(-1);
493
494	sig = oem->signature;
495	if (!sig)
496		return(-2);
497
498	from = oem->range.from;
499	to = oem->range.to;
500	if ( (to<=from) || (from<BIOS_START) || (to>(BIOS_START+BIOS_SIZE)) )
501		return(-3);
502
503	while (sig->anchor != NULL) {
504		str = sig->anchor;
505		len = strlen(str);
506		off = sig->offset;
507		tot = sig->totlen;
508		/* make sure offset doesn't go beyond bios area */
509		if ( (to+off)>(BIOS_START+BIOS_SIZE) ||
510					((from+off)<BIOS_START) ) {
511			printf("sys/i386/i386/bios.c: sig '%s' "
512				"from 0x%0x to 0x%0x offset %d "
513				"out of BIOS bounds 0x%0x - 0x%0x\n",
514				str, from, to, off,
515				BIOS_START, BIOS_START+BIOS_SIZE);
516			return(-4);
517		}
518		/* make sure we don't overrun return buffer */
519		if (idx + tot > maxlen - 1) {
520			printf("sys/i386/i386/bios.c: sig '%s' "
521				"idx %d + tot %d = %d > maxlen-1 %d\n",
522				str, idx, tot, idx+tot, maxlen-1);
523			return(-5);
524		}
525		bios_str = NULL;
526		s = (u_char *)BIOS_PADDRTOVADDR(from);
527		se = (u_char *)BIOS_PADDRTOVADDR(to-len);
528		for (; s<se; s++) {
529			if (!bcmp(str, s, len)) {
530				bios_str = s;
531				break;
532			}
533		}
534		/*
535		*  store pretty version of totlen bytes of bios string with
536		*  given offset; 0x20 - 0x7E are printable; uniquify spaces
537		*/
538		if (bios_str) {
539			for (i=0; i<tot; i++) {
540				c = bios_str[i+off];
541				if ( (c < 0x20) || (c > 0x7E) )
542					c = ' ';
543				if (idx == 0) {
544					if (c != ' ')
545						buffer[idx++] = c;
546				} else if ( (c != ' ') ||
547					((c == ' ') && (buffer[idx-1] != ' ')) )
548						buffer[idx++] = c;
549			}
550		}
551		sig++;
552	}
553	/* remove a final trailing space */
554	if ( (idx > 1) && (buffer[idx-1] == ' ') )
555		idx--;
556	buffer[idx] = '\0';
557	return (idx);
558}
559
560#ifdef DEV_ISA
561/*
562 * PnP BIOS interface; enumerate devices only known to the system
563 * BIOS and save information about them for later use.
564 */
565
566struct pnp_sysdev
567{
568    u_int16_t	size;
569    u_int8_t	handle;
570    u_int32_t	devid;
571    u_int8_t	type[3];
572    u_int16_t	attrib;
573#define PNPATTR_NODISABLE	(1<<0)	/* can't be disabled */
574#define PNPATTR_NOCONFIG	(1<<1)	/* can't be configured */
575#define PNPATTR_OUTPUT		(1<<2)	/* can be primary output */
576#define PNPATTR_INPUT		(1<<3)	/* can be primary input */
577#define PNPATTR_BOOTABLE	(1<<4)	/* can be booted from */
578#define PNPATTR_DOCK		(1<<5)	/* is a docking station */
579#define PNPATTR_REMOVEABLE	(1<<6)	/* device is removeable */
580#define PNPATTR_CONFIG_STATIC	(0)
581#define PNPATTR_CONFIG_DYNAMIC	(1)
582#define PNPATTR_CONFIG_DYNONLY	(3)
583#define PNPATTR_CONFIG(a)	(((a) >> 7) & 0x3)
584    /* device-specific data comes here */
585    u_int8_t	devdata[0];
586} __packed;
587
588/* We have to cluster arguments within a 64k range for the bios16 call */
589struct pnp_sysdevargs
590{
591    u_int16_t	next;
592    struct pnp_sysdev node;
593};
594
595/*
596 * This function is called after the bus has assigned resource
597 * locations for a logical device.
598 */
599static void
600pnpbios_set_config(void *arg, struct isa_config *config, int enable)
601{
602}
603
604/*
605 * Quiz the PnP BIOS, build a list of PNP IDs and resource data.
606 */
607static void
608pnpbios_identify(driver_t *driver, device_t parent)
609{
610    struct PnPBIOS_table	*pt = PnPBIOStable;
611    struct bios_args		args;
612    struct pnp_sysdev		*pd;
613    struct pnp_sysdevargs	*pda;
614    u_int16_t			ndevs, bigdev;
615    int				error, currdev;
616    u_int8_t			*devnodebuf, tag;
617    u_int32_t			*devid, *compid;
618    int				idx, left;
619    device_t			dev;
620
621    /* no PnP BIOS information */
622    if (pt == NULL)
623	return;
624
625    /* Check to see if ACPI is already active. */
626    dev = devclass_get_device(devclass_find("acpi"), 0);
627    if (dev != NULL && device_is_attached(dev))
628	return;
629
630    /* get count of PnP devices */
631    bzero(&args, sizeof(args));
632    args.seg.code16.base = BIOS_PADDRTOVADDR(pt->pmentrybase);
633    args.seg.code16.limit = 0xffff;		/* XXX ? */
634    args.seg.data.base = BIOS_PADDRTOVADDR(pt->pmdataseg);
635    args.seg.data.limit = 0xffff;
636    args.entry = pt->pmentryoffset;
637
638    if ((error = bios16(&args, PNP_COUNT_DEVNODES, &ndevs, &bigdev)) || (args.r.eax & 0xff)) {
639	printf("pnpbios: error %d/%x getting device count/size limit\n", error, args.r.eax);
640	return;
641    }
642    ndevs &= 0xff;				/* clear high byte garbage */
643    if (bootverbose)
644	printf("pnpbios: %d devices, largest %d bytes\n", ndevs, bigdev);
645
646    devnodebuf = malloc(bigdev + (sizeof(struct pnp_sysdevargs) - sizeof(struct pnp_sysdev)),
647			M_DEVBUF, M_NOWAIT);
648    if (devnodebuf == NULL) {
649	printf("pnpbios: cannot allocate memory, bailing\n");
650	return;
651    }
652    pda = (struct pnp_sysdevargs *)devnodebuf;
653    pd = &pda->node;
654
655    for (currdev = 0, left = ndevs; (currdev != 0xff) && (left > 0); left--) {
656
657	bzero(pd, bigdev);
658	pda->next = currdev;
659	/* get current configuration */
660	if ((error = bios16(&args, PNP_GET_DEVNODE, &pda->next, &pda->node, 1))) {
661	    printf("pnpbios: error %d making BIOS16 call\n", error);
662	    break;
663	}
664	if ((error = (args.r.eax & 0xff))) {
665	    if (bootverbose)
666		printf("pnpbios: %s 0x%x fetching node %d\n", error & 0x80 ? "error" : "warning", error, currdev);
667	    if (error & 0x80)
668		break;
669	}
670	currdev = pda->next;
671	if (pd->size < sizeof(struct pnp_sysdev)) {
672	    printf("pnpbios: bogus system node data, aborting scan\n");
673	    break;
674	}
675
676	/*
677	 * Ignore PICs so that we don't have to worry about the PICs
678	 * claiming IRQs to prevent their use.  The PIC drivers
679	 * already ensure that invalid IRQs are not used.
680	 */
681	if (!strcmp(pnp_eisaformat(pd->devid), "PNP0000"))	/* ISA PIC */
682	    continue;
683	if (!strcmp(pnp_eisaformat(pd->devid), "PNP0003"))	/* APIC */
684	    continue;
685
686	/* Add the device and parse its resources */
687	dev = BUS_ADD_CHILD(parent, ISA_ORDER_PNPBIOS, NULL, -1);
688	isa_set_vendorid(dev, pd->devid);
689	isa_set_logicalid(dev, pd->devid);
690	/*
691	 * It appears that some PnP BIOS doesn't allow us to re-enable
692	 * the embedded system device once it is disabled.  We shall
693	 * mark all system device nodes as "cannot be disabled", regardless
694	 * of actual settings in the device attribute byte.
695	 * XXX
696	isa_set_configattr(dev,
697	    ((pd->attrib & PNPATTR_NODISABLE) ?  0 : ISACFGATTR_CANDISABLE) |
698	    ((!(pd->attrib & PNPATTR_NOCONFIG) &&
699		PNPATTR_CONFIG(pd->attrib) != PNPATTR_CONFIG_STATIC)
700		? ISACFGATTR_DYNAMIC : 0));
701	 */
702	isa_set_configattr(dev,
703	    (!(pd->attrib & PNPATTR_NOCONFIG) &&
704		PNPATTR_CONFIG(pd->attrib) != PNPATTR_CONFIG_STATIC)
705		? ISACFGATTR_DYNAMIC : 0);
706	isa_set_pnpbios_handle(dev, pd->handle);
707	ISA_SET_CONFIG_CALLBACK(parent, dev, pnpbios_set_config, 0);
708	pnp_parse_resources(dev, &pd->devdata[0],
709	    pd->size - sizeof(struct pnp_sysdev), 0);
710	if (!device_get_desc(dev))
711	    device_set_desc_copy(dev, pnp_eisaformat(pd->devid));
712
713	/* Find device IDs */
714	devid = &pd->devid;
715	compid = NULL;
716
717	/* look for a compatible device ID too */
718	left = pd->size - sizeof(struct pnp_sysdev);
719	idx = 0;
720	while (idx < left) {
721	    tag = pd->devdata[idx++];
722	    if (PNP_RES_TYPE(tag) == 0) {
723		/* Small resource */
724		switch (PNP_SRES_NUM(tag)) {
725		case PNP_TAG_COMPAT_DEVICE:
726		    compid = (u_int32_t *)(pd->devdata + idx);
727		    if (bootverbose)
728			printf("pnpbios: node %d compat ID 0x%08x\n", pd->handle, *compid);
729		    /* FALLTHROUGH */
730		case PNP_TAG_END:
731		    idx = left;
732		    break;
733		default:
734		    idx += PNP_SRES_LEN(tag);
735		    break;
736		}
737	    } else
738		/* Large resource, skip it */
739		idx += *(u_int16_t *)(pd->devdata + idx) + 2;
740	}
741	if (bootverbose) {
742	    printf("pnpbios: handle %d device ID %s (%08x)",
743		   pd->handle, pnp_eisaformat(*devid), *devid);
744	    if (compid != NULL)
745		printf(" compat ID %s (%08x)",
746		       pnp_eisaformat(*compid), *compid);
747	    printf("\n");
748	}
749    }
750}
751
752static device_method_t pnpbios_methods[] = {
753	/* Device interface */
754	DEVMETHOD(device_identify,	pnpbios_identify),
755
756	{ 0, 0 }
757};
758
759static driver_t pnpbios_driver = {
760	"pnpbios",
761	pnpbios_methods,
762	1,			/* no softc */
763};
764
765static devclass_t pnpbios_devclass;
766
767DRIVER_MODULE(pnpbios, isa, pnpbios_driver, pnpbios_devclass, 0, 0);
768#endif /* DEV_ISA */
769