xref: /freebsd/sys/isa/pnp.c (revision 97cb52fa9aefd90fad38790fded50905aeeb9b9e)
1 /*
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 1996, Sujal M. Patel
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  *      from: pnp.c,v 1.11 1999/05/06 22:11:19 peter Exp
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/kernel.h>
37 #include <sys/module.h>
38 #include <sys/bus.h>
39 #include <sys/endian.h>
40 #include <sys/malloc.h>
41 #include <isa/isavar.h>
42 #include <isa/pnpreg.h>
43 #include <isa/pnpvar.h>
44 #include <machine/bus.h>
45 
46 typedef struct _pnp_id {
47 	uint32_t vendor_id;
48 	uint32_t serial;
49 	u_char checksum;
50 } pnp_id;
51 
52 struct pnp_set_config_arg {
53 	int	csn;		/* Card number to configure */
54 	int	ldn;		/* Logical device on card */
55 };
56 
57 struct pnp_quirk {
58 	uint32_t vendor_id;	/* Vendor of the card */
59 	uint32_t logical_id;	/* ID of the device with quirk */
60 	int	type;
61 #define PNP_QUIRK_WRITE_REG	1 /* Need to write a pnp register  */
62 #define PNP_QUIRK_EXTRA_IO	2 /* Has extra io ports  */
63 	int	arg1;
64 	int	arg2;
65 };
66 
67 struct pnp_quirk pnp_quirks[] = {
68 	/*
69 	 * The Gravis UltraSound needs register 0xf2 to be set to 0xff
70 	 * to enable power.
71 	 * XXX need to know the logical device id.
72 	 */
73 	{ 0x0100561e /* GRV0001 */,	0,
74 	  PNP_QUIRK_WRITE_REG,	0xf2,	 0xff },
75 	/*
76 	 * An emu8000 does not give us other than the first
77 	 * port.
78 	 */
79 	{ 0x26008c0e /* SB16 */,	0x21008c0e,
80 	  PNP_QUIRK_EXTRA_IO,	0x400,	 0x800 },
81 	{ 0x42008c0e /* SB32(CTL0042) */,	0x21008c0e,
82 	  PNP_QUIRK_EXTRA_IO,	0x400,	 0x800 },
83 	{ 0x44008c0e /* SB32(CTL0044) */,	0x21008c0e,
84 	  PNP_QUIRK_EXTRA_IO,	0x400,	 0x800 },
85 	{ 0x49008c0e /* SB32(CTL0049) */,	0x21008c0e,
86 	  PNP_QUIRK_EXTRA_IO,	0x400,	 0x800 },
87 	{ 0xf1008c0e /* SB32(CTL00f1) */,	0x21008c0e,
88 	  PNP_QUIRK_EXTRA_IO,	0x400,	 0x800 },
89 	{ 0xc1008c0e /* SB64(CTL00c1) */,	0x22008c0e,
90 	  PNP_QUIRK_EXTRA_IO,	0x400,	 0x800 },
91 	{ 0xc5008c0e /* SB64(CTL00c5) */,	0x22008c0e,
92 	  PNP_QUIRK_EXTRA_IO,	0x400,	 0x800 },
93 	{ 0xe4008c0e /* SB64(CTL00e4) */,	0x22008c0e,
94 	  PNP_QUIRK_EXTRA_IO,	0x400,	 0x800 },
95 
96 	{ 0 }
97 };
98 
99 /* The READ_DATA port that we are using currently */
100 static int pnp_rd_port;
101 
102 static void   pnp_send_initiation_key(void);
103 static int    pnp_get_serial(pnp_id *p);
104 static int    pnp_isolation_protocol(device_t parent);
105 
106 char *
107 pnp_eisaformat(uint32_t id)
108 {
109 	uint8_t *data;
110 	static char idbuf[8];
111 	const char  hextoascii[] = "0123456789abcdef";
112 
113 	id = htole32(id);
114 	data = (uint8_t *)&id;
115 	idbuf[0] = '@' + ((data[0] & 0x7c) >> 2);
116 	idbuf[1] = '@' + (((data[0] & 0x3) << 3) + ((data[1] & 0xe0) >> 5));
117 	idbuf[2] = '@' + (data[1] & 0x1f);
118 	idbuf[3] = hextoascii[(data[2] >> 4)];
119 	idbuf[4] = hextoascii[(data[2] & 0xf)];
120 	idbuf[5] = hextoascii[(data[3] >> 4)];
121 	idbuf[6] = hextoascii[(data[3] & 0xf)];
122 	idbuf[7] = 0;
123 	return(idbuf);
124 }
125 
126 static void
127 pnp_write(int d, u_char r)
128 {
129 	outb (_PNP_ADDRESS, d);
130 	outb (_PNP_WRITE_DATA, r);
131 }
132 
133 /*
134  * Send Initiation LFSR as described in "Plug and Play ISA Specification",
135  * Intel May 94.
136  */
137 static void
138 pnp_send_initiation_key()
139 {
140 	int cur, i;
141 
142 	/* Reset the LSFR */
143 	outb(_PNP_ADDRESS, 0);
144 	outb(_PNP_ADDRESS, 0); /* yes, we do need it twice! */
145 
146 	cur = 0x6a;
147 	outb(_PNP_ADDRESS, cur);
148 
149 	for (i = 1; i < 32; i++) {
150 		cur = (cur >> 1) | (((cur ^ (cur >> 1)) << 7) & 0xff);
151 		outb(_PNP_ADDRESS, cur);
152 	}
153 }
154 
155 
156 /*
157  * Get the device's serial number.  Returns 1 if the serial is valid.
158  */
159 static int
160 pnp_get_serial(pnp_id *p)
161 {
162 	int i, bit, valid = 0, sum = 0x6a;
163 	u_char *data = (u_char *)p;
164 
165 	bzero(data, sizeof(char) * 9);
166 	outb(_PNP_ADDRESS, PNP_SERIAL_ISOLATION);
167 	for (i = 0; i < 72; i++) {
168 		bit = inb((pnp_rd_port << 2) | 0x3) == 0x55;
169 		DELAY(250);	/* Delay 250 usec */
170 
171 		/* Can't Short Circuit the next evaluation, so 'and' is last */
172 		bit = (inb((pnp_rd_port << 2) | 0x3) == 0xaa) && bit;
173 		DELAY(250);	/* Delay 250 usec */
174 
175 		valid = valid || bit;
176 		if (i < 64)
177 			sum = (sum >> 1) |
178 			  (((sum ^ (sum >> 1) ^ bit) << 7) & 0xff);
179 		data[i / 8] = (data[i / 8] >> 1) | (bit ? 0x80 : 0);
180 	}
181 
182 	valid = valid && (data[8] == sum);
183 
184 	return (valid);
185 }
186 
187 /*
188  * Fill's the buffer with resource info from the device.
189  * Returns the number of characters read.
190  */
191 static int
192 pnp_get_resource_info(u_char *buffer, int len)
193 {
194 	int i, j, count;
195 	u_char temp;
196 
197 	count = 0;
198 	for (i = 0; i < len; i++) {
199 		outb(_PNP_ADDRESS, PNP_STATUS);
200 		for (j = 0; j < 100; j++) {
201 			if ((inb((pnp_rd_port << 2) | 0x3)) & 0x1)
202 				break;
203 			DELAY(10);
204 		}
205 		if (j == 100) {
206 			printf("PnP device failed to report resource data\n");
207 			return (count);
208 		}
209 		outb(_PNP_ADDRESS, PNP_RESOURCE_DATA);
210 		temp = inb((pnp_rd_port << 2) | 0x3);
211 		if (buffer != NULL)
212 			buffer[i] = temp;
213 		count++;
214 	}
215 	return (count);
216 }
217 
218 /*
219  * This function is called after the bus has assigned resource
220  * locations for a logical device.
221  */
222 static void
223 pnp_set_config(void *arg, struct isa_config *config, int enable)
224 {
225 	int csn = ((struct pnp_set_config_arg *) arg)->csn;
226 	int ldn = ((struct pnp_set_config_arg *) arg)->ldn;
227 	int i;
228 
229 	/*
230 	 * First put all cards into Sleep state with the initiation
231 	 * key, then put our card into Config state.
232 	 */
233 	pnp_send_initiation_key();
234 	pnp_write(PNP_WAKE, csn);
235 
236 	/*
237 	 * Select our logical device so that we can program it.
238 	 */
239 	pnp_write(PNP_SET_LDN, ldn);
240 
241 	/*
242 	 * Constrain the number of resources we will try to program
243 	 */
244 	if (config->ic_nmem > ISA_PNP_NMEM) {
245 		printf("too many ISA memory ranges (%d > %d)\n",
246 		    config->ic_nmem, ISA_PNP_NMEM);
247 		config->ic_nmem = ISA_PNP_NMEM;
248 	}
249 	if (config->ic_nport > ISA_PNP_NPORT) {
250 		printf("too many ISA I/O ranges (%d > %d)\n", config->ic_nport,
251 		    ISA_PNP_NPORT);
252 		config->ic_nport = ISA_PNP_NPORT;
253 	}
254 	if (config->ic_nirq > ISA_PNP_NIRQ) {
255 		printf("too many ISA IRQs (%d > %d)\n", config->ic_nirq,
256 		    ISA_PNP_NIRQ);
257 		config->ic_nirq = ISA_PNP_NIRQ;
258 	}
259 	if (config->ic_ndrq > ISA_PNP_NDRQ) {
260 		printf("too many ISA DRQs (%d > %d)\n", config->ic_ndrq,
261 		    ISA_PNP_NDRQ);
262 		config->ic_ndrq = ISA_PNP_NDRQ;
263 	}
264 
265 	/*
266 	 * Now program the resources.
267 	 */
268 	for (i = 0; i < config->ic_nmem; i++) {
269 		uint32_t start;
270 		uint32_t size;
271 
272 		/* XXX: should handle memory control register, 32 bit memory */
273 		if (config->ic_mem[i].ir_size == 0) {
274 			pnp_write(PNP_MEM_BASE_HIGH(i), 0);
275 			pnp_write(PNP_MEM_BASE_LOW(i), 0);
276 			pnp_write(PNP_MEM_RANGE_HIGH(i), 0);
277 			pnp_write(PNP_MEM_RANGE_LOW(i), 0);
278 		} else {
279 			start = config->ic_mem[i].ir_start;
280 			size =  config->ic_mem[i].ir_size;
281 			if (start & 0xff)
282 				panic("pnp_set_config: bogus memory assignment");
283 			pnp_write(PNP_MEM_BASE_HIGH(i), (start >> 16) & 0xff);
284 			pnp_write(PNP_MEM_BASE_LOW(i), (start >> 8) & 0xff);
285 			pnp_write(PNP_MEM_RANGE_HIGH(i), (size >> 16) & 0xff);
286 			pnp_write(PNP_MEM_RANGE_LOW(i), (size >> 8) & 0xff);
287 		}
288 	}
289 	for (; i < ISA_PNP_NMEM; i++) {
290 		pnp_write(PNP_MEM_BASE_HIGH(i), 0);
291 		pnp_write(PNP_MEM_BASE_LOW(i), 0);
292 		pnp_write(PNP_MEM_RANGE_HIGH(i), 0);
293 		pnp_write(PNP_MEM_RANGE_LOW(i), 0);
294 	}
295 
296 	for (i = 0; i < config->ic_nport; i++) {
297 		uint32_t start;
298 
299 		if (config->ic_port[i].ir_size == 0) {
300 			pnp_write(PNP_IO_BASE_HIGH(i), 0);
301 			pnp_write(PNP_IO_BASE_LOW(i), 0);
302 		} else {
303 			start = config->ic_port[i].ir_start;
304 			pnp_write(PNP_IO_BASE_HIGH(i), (start >> 8) & 0xff);
305 			pnp_write(PNP_IO_BASE_LOW(i), (start >> 0) & 0xff);
306 		}
307 	}
308 	for (; i < ISA_PNP_NPORT; i++) {
309 		pnp_write(PNP_IO_BASE_HIGH(i), 0);
310 		pnp_write(PNP_IO_BASE_LOW(i), 0);
311 	}
312 
313 	for (i = 0; i < config->ic_nirq; i++) {
314 		int irq;
315 
316 		/* XXX: interrupt type */
317 		if (config->ic_irqmask[i] == 0) {
318 			pnp_write(PNP_IRQ_LEVEL(i), 0);
319 			pnp_write(PNP_IRQ_TYPE(i), 2);
320 		} else {
321 			irq = ffs(config->ic_irqmask[i]) - 1;
322 			pnp_write(PNP_IRQ_LEVEL(i), irq);
323 			pnp_write(PNP_IRQ_TYPE(i), 2); /* XXX */
324 		}
325 	}
326 	for (; i < ISA_PNP_NIRQ; i++) {
327 		/*
328 		 * IRQ 0 is not a valid interrupt selection and
329 		 * represents no interrupt selection.
330 		 */
331 		pnp_write(PNP_IRQ_LEVEL(i), 0);
332 		pnp_write(PNP_IRQ_TYPE(i), 2);
333 	}
334 
335 	for (i = 0; i < config->ic_ndrq; i++) {
336 		int drq;
337 
338 		if (config->ic_drqmask[i] == 0) {
339 			pnp_write(PNP_DMA_CHANNEL(i), 4);
340 		} else {
341 			drq = ffs(config->ic_drqmask[i]) - 1;
342 			pnp_write(PNP_DMA_CHANNEL(i), drq);
343 		}
344 	}
345 	for (; i < ISA_PNP_NDRQ; i++) {
346 		/*
347 		 * DMA channel 4, the cascade channel is used to
348 		 * indicate no DMA channel is active.
349 		 */
350 		pnp_write(PNP_DMA_CHANNEL(i), 4);
351 	}
352 
353 	pnp_write(PNP_ACTIVATE, enable ? 1 : 0);
354 
355 	/*
356 	 * Wake everyone up again, we are finished.
357 	 */
358 	pnp_write(PNP_CONFIG_CONTROL, PNP_CONFIG_CONTROL_WAIT_FOR_KEY);
359 }
360 
361 /*
362  * Process quirks for a logical device.. The card must be in Config state.
363  */
364 void
365 pnp_check_quirks(uint32_t vendor_id, uint32_t logical_id, int ldn,
366     struct isa_config *config)
367 {
368 	struct pnp_quirk *qp;
369 
370 	for (qp = &pnp_quirks[0]; qp->vendor_id; qp++) {
371 		if (qp->vendor_id == vendor_id
372 		    && (qp->logical_id == 0 || qp->logical_id == logical_id)) {
373 			switch (qp->type) {
374 			case PNP_QUIRK_WRITE_REG:
375 				pnp_write(PNP_SET_LDN, ldn);
376 				pnp_write(qp->arg1, qp->arg2);
377 				break;
378 			case PNP_QUIRK_EXTRA_IO:
379 				if (config == NULL)
380 					break;
381 				if (qp->arg1 != 0) {
382 					config->ic_nport++;
383 					config->ic_port[config->ic_nport - 1] = config->ic_port[0];
384 					config->ic_port[config->ic_nport - 1].ir_start += qp->arg1;
385 					config->ic_port[config->ic_nport - 1].ir_end += qp->arg1;
386 				}
387 				if (qp->arg2 != 0) {
388 					config->ic_nport++;
389 					config->ic_port[config->ic_nport - 1] = config->ic_port[0];
390 					config->ic_port[config->ic_nport - 1].ir_start += qp->arg2;
391 					config->ic_port[config->ic_nport - 1].ir_end += qp->arg2;
392 				}
393 				break;
394 			}
395 		}
396 	}
397 }
398 
399 /*
400  * Scan Resource Data for Logical Devices.
401  *
402  * This function exits as soon as it gets an error reading *ANY*
403  * Resource Data or it reaches the end of Resource Data.  In the first
404  * case the return value will be TRUE, FALSE otherwise.
405  */
406 static int
407 pnp_create_devices(device_t parent, pnp_id *p, int csn,
408     u_char *resources, int len)
409 {
410 	u_char tag, *resp, *resinfo, *startres = NULL;
411 	int large_len, scanning = len, retval = FALSE;
412 	uint32_t logical_id;
413 	device_t dev = 0;
414 	int ldn = 0;
415 	struct pnp_set_config_arg *csnldn;
416 	char buf[100];
417 	char *desc = NULL;
418 
419 	resp = resources;
420 	while (scanning > 0) {
421 		tag = *resp++;
422 		scanning--;
423 		if (PNP_RES_TYPE(tag) != 0) {
424 			/* Large resource */
425 			if (scanning < 2) {
426 				scanning = 0;
427 				continue;
428 			}
429 			large_len = resp[0] + (resp[1] << 8);
430 			resp += 2;
431 
432 			if (scanning < large_len) {
433 				scanning = 0;
434 				continue;
435 			}
436 			resinfo = resp;
437 			resp += large_len;
438 			scanning -= large_len;
439 
440 			if (PNP_LRES_NUM(tag) == PNP_TAG_ID_ANSI) {
441 				if (dev) {
442 					/*
443 					 * This is an optional device
444 					 * identifier string. Skip it
445 					 * for now.
446 					 */
447 					continue;
448 				}
449 				/* else mandately card identifier string */
450 				if (large_len > sizeof(buf) - 1)
451 					large_len = sizeof(buf) - 1;
452 				bcopy(resinfo, buf, large_len);
453 
454 				/*
455 				 * Trim trailing spaces.
456 				 */
457 				while (buf[large_len-1] == ' ')
458 					large_len--;
459 				buf[large_len] = '\0';
460 				desc = buf;
461 				continue;
462 			}
463 
464 			continue;
465 		}
466 
467 		/* Small resource */
468 		if (scanning < PNP_SRES_LEN(tag)) {
469 			scanning = 0;
470 			continue;
471 		}
472 		resinfo = resp;
473 		resp += PNP_SRES_LEN(tag);
474 		scanning -= PNP_SRES_LEN(tag);
475 
476 		switch (PNP_SRES_NUM(tag)) {
477 		case PNP_TAG_LOGICAL_DEVICE:
478 			/*
479 			 * Parse the resources for the previous
480 			 * logical device (if any).
481 			 */
482 			if (startres) {
483 				pnp_parse_resources(dev, startres,
484 				    resinfo - startres - 1, ldn);
485 				dev = 0;
486 				startres = NULL;
487 			}
488 
489 			/*
490 			 * A new logical device. Scan for end of
491 			 * resources.
492 			 */
493 			bcopy(resinfo, &logical_id, 4);
494 			pnp_check_quirks(p->vendor_id, logical_id, ldn, NULL);
495 			dev = BUS_ADD_CHILD(parent, ISA_ORDER_PNP, NULL, -1);
496 			if (desc)
497 				device_set_desc_copy(dev, desc);
498 			else
499 				device_set_desc_copy(dev,
500 				    pnp_eisaformat(logical_id));
501 			isa_set_vendorid(dev, p->vendor_id);
502 			isa_set_serial(dev, p->serial);
503 			isa_set_logicalid(dev, logical_id);
504 			isa_set_configattr(dev,
505 			    ISACFGATTR_CANDISABLE | ISACFGATTR_DYNAMIC);
506 			csnldn = malloc(sizeof *csnldn, M_DEVBUF, M_NOWAIT);
507 			if (!csnldn) {
508 				device_printf(parent, "out of memory\n");
509 				scanning = 0;
510 				break;
511 			}
512 			csnldn->csn = csn;
513 			csnldn->ldn = ldn;
514 			ISA_SET_CONFIG_CALLBACK(parent, dev, pnp_set_config,
515 			    csnldn);
516 			isa_set_pnp_csn(dev, csn);
517 			isa_set_pnp_ldn(dev, ldn);
518 			ldn++;
519 			startres = resp;
520 			break;
521 
522 		case PNP_TAG_END:
523 			if (!startres) {
524 				device_printf(parent, "malformed resources\n");
525 				scanning = 0;
526 				break;
527 			}
528 			pnp_parse_resources(dev, startres,
529 			    resinfo - startres - 1, ldn);
530 			dev = 0;
531 			startres = NULL;
532 			scanning = 0;
533 			break;
534 
535 		default:
536 			/* Skip this resource */
537 			break;
538 		}
539 	}
540 
541 	return (retval);
542 }
543 
544 /*
545  * Read 'amount' bytes of resources from the card, allocating memory
546  * as needed. If a buffer is already available, it should be passed in
547  * '*resourcesp' and its length in '*spacep'. The number of resource
548  * bytes already in the buffer should be passed in '*lenp'. The memory
549  * allocated will be returned in '*resourcesp' with its size and the
550  * number of bytes of resources in '*spacep' and '*lenp' respectively.
551  *
552  * XXX: Multiple problems here, we forget to free() stuff in one
553  * XXX: error return, and in another case we free (*resourcesp) but
554  * XXX: don't tell the caller.
555  */
556 static int
557 pnp_read_bytes(int amount, u_char **resourcesp, int *spacep, int *lenp)
558 {
559 	u_char *resources = *resourcesp;
560 	u_char *newres;
561 	int space = *spacep;
562 	int len = *lenp;
563 
564 	if (space == 0) {
565 		space = 1024;
566 		resources = malloc(space, M_TEMP, M_NOWAIT);
567 		if (!resources)
568 			return (ENOMEM);
569 	}
570 
571 	if (len + amount > space) {
572 		int extra = 1024;
573 		while (len + amount > space + extra)
574 			extra += 1024;
575 		newres = malloc(space + extra, M_TEMP, M_NOWAIT);
576 		if (!newres) {
577 			/* XXX: free resources */
578 			return (ENOMEM);
579 		}
580 		bcopy(resources, newres, len);
581 		free(resources, M_TEMP);
582 		resources = newres;
583 		space += extra;
584 	}
585 
586 	if (pnp_get_resource_info(resources + len, amount) != amount)
587 		return (EINVAL);
588 	len += amount;
589 
590 	*resourcesp = resources;
591 	*spacep = space;
592 	*lenp = len;
593 
594 	return (0);
595 }
596 
597 /*
598  * Read all resources from the card, allocating memory as needed. If a
599  * buffer is already available, it should be passed in '*resourcesp'
600  * and its length in '*spacep'. The memory allocated will be returned
601  * in '*resourcesp' with its size and the number of bytes of resources
602  * in '*spacep' and '*lenp' respectively.
603  */
604 static int
605 pnp_read_resources(u_char **resourcesp, int *spacep, int *lenp)
606 {
607 	u_char *resources = *resourcesp;
608 	int space = *spacep;
609 	int len = 0;
610 	int error, done;
611 	u_char tag;
612 
613 	error = 0;
614 	done = 0;
615 	while (!done) {
616 		error = pnp_read_bytes(1, &resources, &space, &len);
617 		if (error)
618 			goto out;
619 		tag = resources[len-1];
620 		if (PNP_RES_TYPE(tag) == 0) {
621 			/*
622 			 * Small resource, read contents.
623 			 */
624 			error = pnp_read_bytes(PNP_SRES_LEN(tag),
625 			    &resources, &space, &len);
626 			if (error)
627 				goto out;
628 			if (PNP_SRES_NUM(tag) == PNP_TAG_END)
629 				done = 1;
630 		} else {
631 			/*
632 			 * Large resource, read length and contents.
633 			 */
634 			error = pnp_read_bytes(2, &resources, &space, &len);
635 			if (error)
636 				goto out;
637 			error = pnp_read_bytes(resources[len-2]
638 			    + (resources[len-1] << 8), &resources, &space,
639 			    &len);
640 			if (error)
641 				goto out;
642 		}
643 	}
644 
645  out:
646 	*resourcesp = resources;
647 	*spacep = space;
648 	*lenp = len;
649 	return (error);
650 }
651 
652 /*
653  * Run the isolation protocol. Use pnp_rd_port as the READ_DATA port
654  * value (caller should try multiple READ_DATA locations before giving
655  * up). Upon exiting, all cards are aware that they should use
656  * pnp_rd_port as the READ_DATA port.
657  *
658  * In the first pass, a csn is assigned to each board and pnp_id's
659  * are saved to an array, pnp_devices. In the second pass, each
660  * card is woken up and the device configuration is called.
661  */
662 static int
663 pnp_isolation_protocol(device_t parent)
664 {
665 	int csn;
666 	pnp_id id;
667 	int found = 0, len;
668 	u_char *resources = NULL;
669 	int space = 0;
670 	int error;
671 
672 	/*
673 	 * Put all cards into the Sleep state so that we can clear
674 	 * their CSNs.
675 	 */
676 	pnp_send_initiation_key();
677 
678 	/*
679 	 * Clear the CSN for all cards.
680 	 */
681 	pnp_write(PNP_CONFIG_CONTROL, PNP_CONFIG_CONTROL_RESET_CSN);
682 
683 	/*
684 	 * Move all cards to the Isolation state.
685 	 */
686 	pnp_write(PNP_WAKE, 0);
687 
688 	/*
689 	 * Tell them where the read point is going to be this time.
690 	 */
691 	pnp_write(PNP_SET_RD_DATA, pnp_rd_port);
692 
693 	for (csn = 1; csn < PNP_MAX_CARDS; csn++) {
694 		/*
695 		 * Start the serial isolation protocol.
696 		 */
697 		outb(_PNP_ADDRESS, PNP_SERIAL_ISOLATION);
698 		DELAY(1000);	/* Delay 1 msec */
699 
700 		if (pnp_get_serial(&id)) {
701 			/*
702 			 * We have read the id from a card
703 			 * successfully. The card which won the
704 			 * isolation protocol will be in Isolation
705 			 * mode and all others will be in Sleep.
706 			 * Program the CSN of the isolated card
707 			 * (taking it to Config state) and read its
708 			 * resources, creating devices as we find
709 			 * logical devices on the card.
710 			 */
711 			pnp_write(PNP_SET_CSN, csn);
712 			if (bootverbose)
713 				printf("Reading PnP configuration for %s.\n",
714 				    pnp_eisaformat(id.vendor_id));
715 			error = pnp_read_resources(&resources, &space, &len);
716 			if (error)
717 				break;
718 			pnp_create_devices(parent, &id, csn, resources, len);
719 			found++;
720 		} else
721 			break;
722 
723 		/*
724 		 * Put this card back to the Sleep state and
725 		 * simultaneously move all cards which don't have a
726 		 * CSN yet to Isolation state.
727 		 */
728 		pnp_write(PNP_WAKE, 0);
729 	}
730 
731 	/*
732 	 * Unless we have chosen the wrong read port, all cards will
733 	 * be in Sleep state. Put them back into WaitForKey for
734 	 * now. Their resources will be programmed later.
735 	 */
736 	pnp_write(PNP_CONFIG_CONTROL, PNP_CONFIG_CONTROL_WAIT_FOR_KEY);
737 
738 	/*
739 	 * Cleanup.
740 	 */
741 	if (resources)
742 		free(resources, M_TEMP);
743 
744 	return (found);
745 }
746 
747 
748 /*
749  * pnp_identify()
750  *
751  * autoconfiguration of pnp devices. This routine just runs the
752  * isolation protocol over several ports, until one is successful.
753  *
754  * may be called more than once ?
755  *
756  */
757 
758 static void
759 pnp_identify(driver_t *driver, device_t parent)
760 {
761 	int num_pnp_devs;
762 
763 	/* Try various READ_DATA ports from 0x203-0x3ff */
764 	for (pnp_rd_port = 0x80; (pnp_rd_port < 0xff); pnp_rd_port += 0x10) {
765 		if (bootverbose)
766 			printf("pnp_identify: Trying Read_Port at %x\n",
767 			    (pnp_rd_port << 2) | 0x3);
768 
769 		num_pnp_devs = pnp_isolation_protocol(parent);
770 		if (num_pnp_devs)
771 			break;
772 	}
773 	if (bootverbose)
774 		printf("PNP Identify complete\n");
775 }
776 
777 static device_method_t pnp_methods[] = {
778 	/* Device interface */
779 	DEVMETHOD(device_identify,	pnp_identify),
780 
781 	{ 0, 0 }
782 };
783 
784 static driver_t pnp_driver = {
785 	"pnp",
786 	pnp_methods,
787 	1,			/* no softc */
788 };
789 
790 static devclass_t pnp_devclass;
791 
792 DRIVER_MODULE(pnp, isa, pnp_driver, pnp_devclass, 0, 0);
793