2 * Copyright (c) 1999 Doug Rabson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * $FreeBSD: src/sys/isa/isa_common.c,v 1.16.2.1 2000/09/16 15:49:52 roger Exp $
27 * $DragonFly: src/sys/bus/isa/isa_common.c,v 1.13 2006/12/22 23:12:16 swildner Exp $
30 * Modifications for Intel architecture by Garrett A. Wollman.
31 * Copyright 1998 Massachusetts Institute of Technology
33 * Permission to use, copy, modify, and distribute this software and
34 * its documentation for any purpose and without fee is hereby
35 * granted, provided that both the above copyright notice and this
36 * permission notice appear in all copies, that both the above
37 * copyright notice and this permission notice appear in all
38 * supporting documentation, and that the name of M.I.T. not be used
39 * in advertising or publicity pertaining to distribution of the
40 * software without specific, written prior permission. M.I.T. makes
41 * no representations about the suitability of this software for any
42 * purpose. It is provided "as is" without express or implied
45 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS
46 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
47 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
48 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
49 * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
50 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
51 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
52 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
53 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
54 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
55 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
60 * Parts of the ISA bus implementation common to all architectures.
63 #include <sys/param.h>
64 #include <sys/systm.h>
65 #include <sys/kernel.h>
67 #include <sys/malloc.h>
68 #include <sys/module.h>
72 #include "isa_common.h"
74 static int isa_print_child (device_t, device_t);
76 MALLOC_DEFINE(M_ISADEV, "isadev", "ISA device");
78 static devclass_t isa_devclass;
79 static int isa_running;
82 * At 'probe' time, we add all the devices which we know about to the
83 * bus. The generic attach routine will probe and attach them if they
87 isa_probe(device_t dev)
89 device_set_desc(dev, "ISA bus");
90 isa_init(); /* Allow machdep code to initialise */
94 extern device_t isa_bus_device;
97 isa_attach(device_t dev)
100 * Arrange for isa_probe_children(dev) to be called later. XXX
102 isa_bus_device = dev;
107 * Find a working set of memory regions for a child using the ranges
108 * in *config and return the regions in *result. Returns non-zero if
109 * a set of ranges was found.
112 isa_find_memory(device_t child,
113 struct isa_config *config,
114 struct isa_config *result)
117 struct resource *res[ISA_NMEM];
120 * First clear out any existing resource definitions.
122 for (i = 0; i < ISA_NMEM; i++) {
123 bus_delete_resource(child, SYS_RES_MEMORY, i);
128 result->ic_nmem = config->ic_nmem;
129 for (i = 0; i < config->ic_nmem; i++) {
130 u_int32_t start, end, size, align;
131 for (start = config->ic_mem[i].ir_start,
132 end = config->ic_mem[i].ir_end,
133 size = config->ic_mem[i].ir_size,
134 align = config->ic_mem[i].ir_align;
135 start + size - 1 <= end;
137 bus_set_resource(child, SYS_RES_MEMORY, i,
139 res[i] = bus_alloc_resource(child,
141 0, ~0, 1, 0 /* !RF_ACTIVE */);
143 result->ic_mem[i].ir_start = start;
144 result->ic_mem[i].ir_end = start + size - 1;
145 result->ic_mem[i].ir_size = size;
146 result->ic_mem[i].ir_align = align;
152 * If we didn't find a place for memory range i, then
161 for (i = 0; i < ISA_NMEM; i++) {
163 bus_release_resource(child, SYS_RES_MEMORY,
171 * Find a working set of port regions for a child using the ranges
172 * in *config and return the regions in *result. Returns non-zero if
173 * a set of ranges was found.
176 isa_find_port(device_t child,
177 struct isa_config *config,
178 struct isa_config *result)
181 struct resource *res[ISA_NPORT];
184 * First clear out any existing resource definitions.
186 for (i = 0; i < ISA_NPORT; i++) {
187 bus_delete_resource(child, SYS_RES_IOPORT, i);
192 result->ic_nport = config->ic_nport;
193 for (i = 0; i < config->ic_nport; i++) {
194 u_int32_t start, end, size, align;
195 for (start = config->ic_port[i].ir_start,
196 end = config->ic_port[i].ir_end,
197 size = config->ic_port[i].ir_size,
198 align = config->ic_port[i].ir_align;
199 start + size - 1 <= end;
201 bus_set_resource(child, SYS_RES_IOPORT, i,
203 res[i] = bus_alloc_resource(child,
205 0, ~0, 1, 0 /* !RF_ACTIVE */);
207 result->ic_port[i].ir_start = start;
208 result->ic_port[i].ir_end = start + size - 1;
209 result->ic_port[i].ir_size = size;
210 result->ic_port[i].ir_align = align;
216 * If we didn't find a place for port range i, then
225 for (i = 0; i < ISA_NPORT; i++) {
227 bus_release_resource(child, SYS_RES_IOPORT,
235 * Return the index of the first bit in the mask (or -1 if mask is empty.
238 find_first_bit(u_int32_t mask)
240 return ffs(mask) - 1;
244 * Return the index of the next bit in the mask, or -1 if there are no more.
247 find_next_bit(u_int32_t mask, int bit)
250 while (bit < 32 && !(mask & (1 << bit)))
258 * Find a working set of irqs for a child using the masks in *config
259 * and return the regions in *result. Returns non-zero if a set of
263 isa_find_irq(device_t child,
264 struct isa_config *config,
265 struct isa_config *result)
268 struct resource *res[ISA_NIRQ];
271 * First clear out any existing resource definitions.
273 for (i = 0; i < ISA_NIRQ; i++) {
274 bus_delete_resource(child, SYS_RES_IRQ, i);
279 result->ic_nirq = config->ic_nirq;
280 for (i = 0; i < config->ic_nirq; i++) {
281 u_int32_t mask = config->ic_irqmask[i];
283 for (irq = find_first_bit(mask);
285 irq = find_next_bit(mask, irq)) {
286 bus_set_resource(child, SYS_RES_IRQ, i,
288 res[i] = bus_alloc_resource(child,
290 0, ~0, 1, 0 /* !RF_ACTIVE */ );
292 result->ic_irqmask[i] = (1 << irq);
298 * If we didn't find a place for irq range i, then
307 for (i = 0; i < ISA_NIRQ; i++) {
309 bus_release_resource(child, SYS_RES_IRQ,
317 * Find a working set of drqs for a child using the masks in *config
318 * and return the regions in *result. Returns non-zero if a set of
322 isa_find_drq(device_t child,
323 struct isa_config *config,
324 struct isa_config *result)
327 struct resource *res[ISA_NDRQ];
330 * First clear out any existing resource definitions.
332 for (i = 0; i < ISA_NDRQ; i++) {
333 bus_delete_resource(child, SYS_RES_DRQ, i);
338 result->ic_ndrq = config->ic_ndrq;
339 for (i = 0; i < config->ic_ndrq; i++) {
340 u_int32_t mask = config->ic_drqmask[i];
342 for (drq = find_first_bit(mask);
344 drq = find_next_bit(mask, drq)) {
345 bus_set_resource(child, SYS_RES_DRQ, i,
347 res[i] = bus_alloc_resource(child,
349 0, ~0, 1, 0 /* !RF_ACTIVE */);
351 result->ic_drqmask[i] = (1 << drq);
357 * If we didn't find a place for drq range i, then
366 for (i = 0; i < ISA_NDRQ; i++) {
368 bus_release_resource(child, SYS_RES_DRQ,
376 * Attempt to find a working set of resources for a device. Return
377 * non-zero if a working configuration is found.
380 isa_assign_resources(device_t child)
382 struct isa_device *idev = DEVTOISA(child);
383 struct isa_config_entry *ice;
384 struct isa_config config;
385 char *reason = "Empty ISA id_configs";
387 bzero(&config, sizeof config);
388 TAILQ_FOREACH(ice, &idev->id_configs, ice_link) {
390 if (!isa_find_memory(child, &ice->ice_config, &config))
393 if (!isa_find_port(child, &ice->ice_config, &config))
396 if (!isa_find_irq(child, &ice->ice_config, &config))
399 if (!isa_find_drq(child, &ice->ice_config, &config))
403 * A working configuration was found enable the device
404 * with this configuration.
406 reason = "no callback";
407 if (idev->id_config_cb) {
408 idev->id_config_cb(idev->id_config_arg,
415 * Disable the device.
417 bus_print_child_header(device_get_parent(child), child);
418 kprintf(" can't assign resources (%s)\n", reason);
420 isa_print_child(device_get_parent(child), child);
421 bzero(&config, sizeof config);
422 if (idev->id_config_cb)
423 idev->id_config_cb(idev->id_config_arg, &config, 0);
424 device_disable(child);
430 * Called after other devices have initialised to probe for isa devices.
433 isa_probe_children(device_t dev)
439 * Create all the children by calling driver's identify methods.
440 * Since this routine is called long after the ISA bus had been
441 * attached, yet never probed, we have to call a hack function that
442 * temporarily sets the bus back to DS_ALIVE to run the probe.
444 bus_generic_probe_hack(dev);
446 if (device_get_children(dev, &children, &nchildren))
450 * First disable all pnp devices so that they don't get
451 * matched by legacy probes.
454 kprintf("isa_probe_children: disabling PnP devices\n");
455 for (i = 0; i < nchildren; i++) {
456 device_t child = children[i];
457 struct isa_device *idev = DEVTOISA(child);
458 struct isa_config config;
460 bzero(&config, sizeof config);
461 if (idev->id_config_cb)
462 idev->id_config_cb(idev->id_config_arg, &config, 0);
466 * Next probe all non-pnp devices so that they claim their
470 kprintf("isa_probe_children: probing non-PnP devices\n");
471 for (i = 0; i < nchildren; i++) {
472 device_t child = children[i];
473 struct isa_device *idev = DEVTOISA(child);
475 if (TAILQ_FIRST(&idev->id_configs))
478 device_probe_and_attach(child);
482 * Finally assign resource to pnp devices and probe them.
485 kprintf("isa_probe_children: probing PnP devices\n");
486 for (i = 0; i < nchildren; i++) {
487 device_t child = children[i];
488 struct isa_device* idev = DEVTOISA(child);
490 if (!TAILQ_FIRST(&idev->id_configs))
493 if (isa_assign_resources(child)) {
494 struct resource_list *rl = &idev->id_resources;
495 struct resource_list_entry *rle;
497 device_probe_and_attach(child);
500 * Claim any unallocated resources to keep other
501 * devices from using them.
503 SLIST_FOREACH(rle, rl, link) {
506 resource_list_alloc(rl, dev, child,
516 kfree(children, M_TEMP);
522 * Add a new child with default ivars.
525 isa_add_child(device_t bus, device_t parent, int order, const char *name, int unit)
528 struct isa_device *idev;
530 idev = kmalloc(sizeof(struct isa_device), M_ISADEV, M_WAITOK | M_ZERO);
532 resource_list_init(&idev->id_resources);
533 TAILQ_INIT(&idev->id_configs);
535 child = device_add_child_ordered(parent, order, name, unit);
536 device_set_ivars(child, idev);
542 isa_print_resources(struct resource_list *rl, const char *name, int type,
543 int count, const char *format)
545 struct resource_list_entry *rle;
550 for (i = 0; i < count; i++) {
551 rle = resource_list_find(rl, type, i);
554 retval += kprintf(" %s ", name);
555 else if (printed > 0)
556 retval += kprintf(",");
558 retval += kprintf(format, rle->start);
559 if (rle->count > 1) {
560 retval += kprintf("-");
561 retval += kprintf(format,
562 rle->start + rle->count - 1);
565 /* check the first few regardless */
573 isa_print_all_resources(device_t dev)
575 struct isa_device *idev = DEVTOISA(dev);
576 struct resource_list *rl = &idev->id_resources;
579 if (SLIST_FIRST(rl) || device_get_flags(dev))
580 retval += kprintf(" at");
582 retval += isa_print_resources(rl, "port", SYS_RES_IOPORT,
584 retval += isa_print_resources(rl, "iomem", SYS_RES_MEMORY,
586 retval += isa_print_resources(rl, "irq", SYS_RES_IRQ,
588 retval += isa_print_resources(rl, "drq", SYS_RES_DRQ,
590 if (device_get_flags(dev))
591 retval += kprintf(" flags %#x", device_get_flags(dev));
597 isa_print_child(device_t bus, device_t dev)
601 retval += bus_print_child_header(bus, dev);
602 retval += isa_print_all_resources(dev);
603 retval += bus_print_child_footer(bus, dev);
609 isa_probe_nomatch(device_t dev, device_t child)
612 bus_print_child_header(dev, child);
613 kprintf(" failed to probe");
614 isa_print_all_resources(child);
615 bus_print_child_footer(dev, child);
622 isa_read_ivar(device_t bus, device_t dev, int index, uintptr_t * result)
624 struct isa_device* idev = DEVTOISA(dev);
625 struct resource_list *rl = &idev->id_resources;
626 struct resource_list_entry *rle;
629 case ISA_IVAR_PORT_0:
630 rle = resource_list_find(rl, SYS_RES_IOPORT, 0);
632 *result = rle->start;
637 case ISA_IVAR_PORT_1:
638 rle = resource_list_find(rl, SYS_RES_IOPORT, 1);
640 *result = rle->start;
645 case ISA_IVAR_PORTSIZE_0:
646 rle = resource_list_find(rl, SYS_RES_IOPORT, 0);
648 *result = rle->count;
653 case ISA_IVAR_PORTSIZE_1:
654 rle = resource_list_find(rl, SYS_RES_IOPORT, 1);
656 *result = rle->count;
661 case ISA_IVAR_MADDR_0:
662 rle = resource_list_find(rl, SYS_RES_MEMORY, 0);
664 *result = rle->start;
669 case ISA_IVAR_MADDR_1:
670 rle = resource_list_find(rl, SYS_RES_MEMORY, 1);
672 *result = rle->start;
677 case ISA_IVAR_MSIZE_0:
678 rle = resource_list_find(rl, SYS_RES_MEMORY, 0);
680 *result = rle->count;
685 case ISA_IVAR_MSIZE_1:
686 rle = resource_list_find(rl, SYS_RES_MEMORY, 1);
688 *result = rle->count;
694 rle = resource_list_find(rl, SYS_RES_IRQ, 0);
696 *result = rle->start;
702 rle = resource_list_find(rl, SYS_RES_IRQ, 1);
704 *result = rle->start;
710 rle = resource_list_find(rl, SYS_RES_DRQ, 0);
712 *result = rle->start;
718 rle = resource_list_find(rl, SYS_RES_DRQ, 1);
720 *result = rle->start;
725 case ISA_IVAR_VENDORID:
726 *result = idev->id_vendorid;
729 case ISA_IVAR_SERIAL:
730 *result = idev->id_serial;
733 case ISA_IVAR_LOGICALID:
734 *result = idev->id_logicalid;
737 case ISA_IVAR_COMPATID:
738 *result = idev->id_compatid;
749 isa_write_ivar(device_t bus, device_t dev,
750 int index, uintptr_t value)
752 struct isa_device* idev = DEVTOISA(dev);
755 case ISA_IVAR_PORT_0:
756 case ISA_IVAR_PORT_1:
757 case ISA_IVAR_PORTSIZE_0:
758 case ISA_IVAR_PORTSIZE_1:
759 case ISA_IVAR_MADDR_0:
760 case ISA_IVAR_MADDR_1:
761 case ISA_IVAR_MSIZE_0:
762 case ISA_IVAR_MSIZE_1:
769 case ISA_IVAR_VENDORID:
770 idev->id_vendorid = value;
773 case ISA_IVAR_SERIAL:
774 idev->id_serial = value;
777 case ISA_IVAR_LOGICALID:
778 idev->id_logicalid = value;
781 case ISA_IVAR_COMPATID:
782 idev->id_compatid = value;
793 * Free any resources which the driver missed or which we were holding for
794 * it (see isa_probe_children).
797 isa_child_detached(device_t dev, device_t child)
799 struct isa_device* idev = DEVTOISA(child);
800 struct resource_list *rl = &idev->id_resources;
801 struct resource_list_entry *rle;
803 if (TAILQ_FIRST(&idev->id_configs)) {
805 * Claim any unallocated resources to keep other
806 * devices from using them.
808 SLIST_FOREACH(rle, rl, link) {
811 resource_list_alloc(rl, dev, child,
820 isa_driver_added(device_t dev, driver_t *driver)
826 * Don't do anything if drivers are dynamically
827 * added during autoconfiguration (cf. ymf724).
828 * since that would end up calling identify
834 DEVICE_IDENTIFY(driver, dev);
835 if (device_get_children(dev, &children, &nchildren))
838 for (i = 0; i < nchildren; i++) {
839 device_t child = children[i];
840 struct isa_device *idev = DEVTOISA(child);
841 struct resource_list *rl = &idev->id_resources;
842 struct resource_list_entry *rle;
844 if (device_get_state(child) != DS_NOTPRESENT)
846 if (!device_is_enabled(child))
850 * Free resources which we were holding on behalf of
853 SLIST_FOREACH(rle, &idev->id_resources, link) {
855 resource_list_release(rl, dev, child,
861 if (TAILQ_FIRST(&idev->id_configs))
862 if (!isa_assign_resources(child))
865 device_probe_and_attach(child);
867 if (TAILQ_FIRST(&idev->id_configs)) {
869 * Claim any unallocated resources to keep other
870 * devices from using them.
872 SLIST_FOREACH(rle, rl, link) {
875 resource_list_alloc(rl, dev, child,
885 kfree(children, M_TEMP);
889 isa_set_resource(device_t dev, device_t child, int type, int rid,
890 u_long start, u_long count)
892 struct isa_device* idev = DEVTOISA(child);
893 struct resource_list *rl = &idev->id_resources;
895 if (type != SYS_RES_IOPORT && type != SYS_RES_MEMORY
896 && type != SYS_RES_IRQ && type != SYS_RES_DRQ)
900 if (type == SYS_RES_IOPORT && rid >= ISA_NPORT)
902 if (type == SYS_RES_MEMORY && rid >= ISA_NMEM)
904 if (type == SYS_RES_IRQ && rid >= ISA_NIRQ)
906 if (type == SYS_RES_DRQ && rid >= ISA_NDRQ)
909 resource_list_add(rl, type, rid, start, start + count - 1, count);
915 isa_get_resource(device_t dev, device_t child, int type, int rid,
916 u_long *startp, u_long *countp)
918 struct isa_device* idev = DEVTOISA(child);
919 struct resource_list *rl = &idev->id_resources;
920 struct resource_list_entry *rle;
922 rle = resource_list_find(rl, type, rid);
927 *startp = rle->start;
929 *countp = rle->count;
935 isa_delete_resource(device_t dev, device_t child, int type, int rid)
937 struct isa_device* idev = DEVTOISA(child);
938 struct resource_list *rl = &idev->id_resources;
939 resource_list_delete(rl, type, rid);
943 isa_add_config(device_t dev, device_t child,
944 int priority, struct isa_config *config)
946 struct isa_device* idev = DEVTOISA(child);
947 struct isa_config_entry *newice, *ice;
949 newice = kmalloc(sizeof *ice, M_DEVBUF, M_WAITOK);
950 newice->ice_priority = priority;
951 newice->ice_config = *config;
953 TAILQ_FOREACH(ice, &idev->id_configs, ice_link) {
954 if (ice->ice_priority > priority)
958 TAILQ_INSERT_BEFORE(ice, newice, ice_link);
960 TAILQ_INSERT_TAIL(&idev->id_configs, newice, ice_link);
966 isa_set_config_callback(device_t dev, device_t child,
967 isa_config_cb *fn, void *arg)
969 struct isa_device* idev = DEVTOISA(child);
971 idev->id_config_cb = fn;
972 idev->id_config_arg = arg;
976 isa_pnp_probe(device_t dev, device_t child, struct isa_pnp_id *ids)
978 struct isa_device* idev = DEVTOISA(child);
980 if (!idev->id_vendorid)
985 * Really ought to support >1 compat id per device.
987 if (idev->id_logicalid == ids->ip_id
988 || idev->id_compatid == ids->ip_id) {
990 device_set_desc(child, ids->ip_desc);
999 static device_method_t isa_methods[] = {
1000 /* Device interface */
1001 DEVMETHOD(device_probe, isa_probe),
1002 DEVMETHOD(device_attach, isa_attach),
1003 DEVMETHOD(device_detach, bus_generic_detach),
1004 DEVMETHOD(device_shutdown, bus_generic_shutdown),
1005 DEVMETHOD(device_suspend, bus_generic_suspend),
1006 DEVMETHOD(device_resume, bus_generic_resume),
1009 DEVMETHOD(bus_add_child, isa_add_child),
1010 DEVMETHOD(bus_print_child, isa_print_child),
1011 DEVMETHOD(bus_probe_nomatch, isa_probe_nomatch),
1012 DEVMETHOD(bus_read_ivar, isa_read_ivar),
1013 DEVMETHOD(bus_write_ivar, isa_write_ivar),
1014 DEVMETHOD(bus_child_detached, isa_child_detached),
1015 DEVMETHOD(bus_driver_added, isa_driver_added),
1016 DEVMETHOD(bus_alloc_resource, isa_alloc_resource),
1017 DEVMETHOD(bus_release_resource, isa_release_resource),
1018 DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
1019 DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
1020 DEVMETHOD(bus_setup_intr, isa_setup_intr),
1021 DEVMETHOD(bus_teardown_intr, isa_teardown_intr),
1022 DEVMETHOD(bus_set_resource, isa_set_resource),
1023 DEVMETHOD(bus_get_resource, isa_get_resource),
1024 DEVMETHOD(bus_delete_resource, isa_delete_resource),
1027 DEVMETHOD(isa_add_config, isa_add_config),
1028 DEVMETHOD(isa_set_config_callback, isa_set_config_callback),
1029 DEVMETHOD(isa_pnp_probe, isa_pnp_probe),
1034 static driver_t isa_driver = {
1041 * ISA can be attached to a PCI-ISA bridge or directly to the nexus.
1043 DRIVER_MODULE(isa, isab, isa_driver, isa_devclass, 0, 0);
1045 DRIVER_MODULE(isa, nexus, isa_driver, isa_devclass, 0, 0);