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pci.c revision 1.48.4.1
      1  1.48.4.1        he /*	$NetBSD: pci.c,v 1.48.4.1 2001/05/15 21:00:40 he Exp $	*/
      2       1.3       cgd 
      3       1.1   mycroft /*
      4      1.37       cgd  * Copyright (c) 1995, 1996, 1997, 1998
      5      1.27       cgd  *     Christopher G. Demetriou.  All rights reserved.
      6      1.39   mycroft  * Copyright (c) 1994 Charles M. Hannum.  All rights reserved.
      7       1.1   mycroft  *
      8       1.1   mycroft  * Redistribution and use in source and binary forms, with or without
      9       1.1   mycroft  * modification, are permitted provided that the following conditions
     10       1.1   mycroft  * are met:
     11       1.1   mycroft  * 1. Redistributions of source code must retain the above copyright
     12       1.1   mycroft  *    notice, this list of conditions and the following disclaimer.
     13       1.1   mycroft  * 2. Redistributions in binary form must reproduce the above copyright
     14       1.1   mycroft  *    notice, this list of conditions and the following disclaimer in the
     15       1.1   mycroft  *    documentation and/or other materials provided with the distribution.
     16       1.1   mycroft  * 3. All advertising materials mentioning features or use of this software
     17       1.1   mycroft  *    must display the following acknowledgement:
     18      1.39   mycroft  *	This product includes software developed by Charles M. Hannum.
     19       1.1   mycroft  * 4. The name of the author may not be used to endorse or promote products
     20       1.1   mycroft  *    derived from this software without specific prior written permission.
     21       1.1   mycroft  *
     22       1.1   mycroft  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     23       1.1   mycroft  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     24       1.1   mycroft  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     25       1.1   mycroft  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     26       1.1   mycroft  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     27       1.1   mycroft  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     28       1.1   mycroft  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     29       1.1   mycroft  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     30       1.1   mycroft  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     31       1.1   mycroft  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     32       1.1   mycroft  */
     33       1.1   mycroft 
     34       1.1   mycroft /*
     35      1.10       cgd  * PCI bus autoconfiguration.
     36       1.1   mycroft  */
     37       1.1   mycroft 
     38      1.45       cgd #include "opt_pci.h"
     39      1.45       cgd 
     40       1.1   mycroft #include <sys/param.h>
     41      1.10       cgd #include <sys/systm.h>
     42       1.1   mycroft #include <sys/device.h>
     43       1.1   mycroft 
     44      1.10       cgd #include <dev/pci/pcireg.h>
     45       1.7       cgd #include <dev/pci/pcivar.h>
     46      1.33       cgd #include <dev/pci/pcidevs.h>
     47      1.10       cgd 
     48      1.45       cgd #ifdef PCI_CONFIG_DUMP
     49      1.45       cgd int pci_config_dump = 1;
     50      1.45       cgd #else
     51      1.45       cgd int pci_config_dump = 0;
     52      1.45       cgd #endif
     53      1.45       cgd 
     54      1.26       cgd int pcimatch __P((struct device *, struct cfdata *, void *));
     55      1.10       cgd void pciattach __P((struct device *, struct device *, void *));
     56      1.10       cgd 
     57      1.34  drochner struct pci_softc {
     58      1.34  drochner 	struct device sc_dev;
     59      1.34  drochner 	bus_space_tag_t sc_iot, sc_memt;
     60      1.34  drochner 	bus_dma_tag_t sc_dmat;
     61      1.34  drochner 	pci_chipset_tag_t sc_pc;
     62      1.34  drochner 	int sc_bus, sc_maxndevs;
     63      1.34  drochner 	u_int sc_intrswiz;
     64      1.34  drochner 	pcitag_t sc_intrtag;
     65      1.34  drochner 	int sc_flags;
     66      1.34  drochner };
     67      1.34  drochner 
     68      1.16   thorpej struct cfattach pci_ca = {
     69      1.34  drochner 	sizeof(struct pci_softc), pcimatch, pciattach
     70      1.10       cgd };
     71      1.10       cgd 
     72      1.34  drochner void	pci_probe_bus __P((struct device *));
     73      1.21       cgd int	pciprint __P((void *, const char *));
     74      1.26       cgd int	pcisubmatch __P((struct device *, struct cfdata *, void *));
     75      1.10       cgd 
     76      1.25       cgd /*
     77      1.38   thorpej  * Important note about PCI-ISA bridges:
     78      1.38   thorpej  *
     79      1.38   thorpej  * Callbacks are used to configure these devices so that ISA/EISA bridges
     80      1.38   thorpej  * can attach their child busses after PCI configuration is done.
     81      1.25       cgd  *
     82      1.25       cgd  * This works because:
     83      1.25       cgd  *	(1) there can be at most one ISA/EISA bridge per PCI bus, and
     84      1.25       cgd  *	(2) any ISA/EISA bridges must be attached to primary PCI
     85      1.25       cgd  *	    busses (i.e. bus zero).
     86      1.25       cgd  *
     87      1.25       cgd  * That boils down to: there can only be one of these outstanding
     88      1.25       cgd  * at a time, it is cleared when configuring PCI bus 0 before any
     89      1.25       cgd  * subdevices have been found, and it is run after all subdevices
     90      1.25       cgd  * of PCI bus 0 have been found.
     91      1.25       cgd  *
     92      1.25       cgd  * This is needed because there are some (legacy) PCI devices which
     93      1.25       cgd  * can show up as ISA/EISA devices as well (the prime example of which
     94      1.25       cgd  * are VGA controllers).  If you attach ISA from a PCI-ISA/EISA bridge,
     95      1.25       cgd  * and the bridge is seen before the video board is, the board can show
     96      1.25       cgd  * up as an ISA device, and that can (bogusly) complicate the PCI device's
     97      1.25       cgd  * attach code, or make the PCI device not be properly attached at all.
     98      1.38   thorpej  *
     99      1.38   thorpej  * We use the generic config_defer() facility to achieve this.
    100      1.25       cgd  */
    101      1.25       cgd 
    102      1.10       cgd int
    103      1.26       cgd pcimatch(parent, cf, aux)
    104      1.10       cgd 	struct device *parent;
    105      1.26       cgd 	struct cfdata *cf;
    106      1.26       cgd 	void *aux;
    107      1.10       cgd {
    108      1.10       cgd 	struct pcibus_attach_args *pba = aux;
    109      1.10       cgd 
    110      1.10       cgd 	if (strcmp(pba->pba_busname, cf->cf_driver->cd_name))
    111      1.10       cgd 		return (0);
    112      1.10       cgd 
    113      1.10       cgd 	/* Check the locators */
    114      1.14       cgd 	if (cf->pcibuscf_bus != PCIBUS_UNK_BUS &&
    115      1.14       cgd 	    cf->pcibuscf_bus != pba->pba_bus)
    116      1.10       cgd 		return (0);
    117      1.10       cgd 
    118      1.10       cgd 	/* sanity */
    119      1.10       cgd 	if (pba->pba_bus < 0 || pba->pba_bus > 255)
    120      1.10       cgd 		return (0);
    121      1.10       cgd 
    122      1.10       cgd 	/*
    123      1.10       cgd 	 * XXX check other (hardware?) indicators
    124      1.10       cgd 	 */
    125      1.10       cgd 
    126      1.10       cgd 	return 1;
    127      1.10       cgd }
    128      1.10       cgd 
    129      1.10       cgd void
    130      1.34  drochner pci_probe_bus(self)
    131      1.34  drochner 	struct device *self;
    132      1.10       cgd {
    133      1.34  drochner 	struct pci_softc *sc = (struct pci_softc *)self;
    134      1.24   thorpej 	bus_space_tag_t iot, memt;
    135      1.18       cgd 	pci_chipset_tag_t pc;
    136      1.37       cgd 	const struct pci_quirkdata *qd;
    137      1.18       cgd 	int bus, device, maxndevs, function, nfunctions;
    138      1.31   thorpej 
    139      1.34  drochner 	iot = sc->sc_iot;
    140      1.34  drochner 	memt = sc->sc_memt;
    141      1.34  drochner 	pc = sc->sc_pc;
    142      1.34  drochner 	bus = sc->sc_bus;
    143      1.34  drochner 	maxndevs = sc->sc_maxndevs;
    144      1.18       cgd 
    145      1.18       cgd 	for (device = 0; device < maxndevs; device++) {
    146      1.10       cgd 		pcitag_t tag;
    147      1.27       cgd 		pcireg_t id, class, intr, bhlcr, csr;
    148      1.10       cgd 		struct pci_attach_args pa;
    149      1.19  christos 		int pin;
    150      1.10       cgd 
    151      1.18       cgd 		tag = pci_make_tag(pc, bus, device, 0);
    152      1.18       cgd 		id = pci_conf_read(pc, tag, PCI_ID_REG);
    153      1.32       cgd 
    154      1.32       cgd 		/* Invalid vendor ID value? */
    155      1.33       cgd 		if (PCI_VENDOR(id) == PCI_VENDOR_INVALID)
    156      1.32       cgd 			continue;
    157      1.32       cgd 		/* XXX Not invalid, but we've done this ~forever. */
    158      1.32       cgd 		if (PCI_VENDOR(id) == 0)
    159      1.10       cgd 			continue;
    160      1.10       cgd 
    161      1.37       cgd 		qd = pci_lookup_quirkdata(PCI_VENDOR(id), PCI_PRODUCT(id));
    162      1.37       cgd 
    163      1.18       cgd 		bhlcr = pci_conf_read(pc, tag, PCI_BHLC_REG);
    164      1.37       cgd 		if (PCI_HDRTYPE_MULTIFN(bhlcr) ||
    165      1.37       cgd 		    (qd != NULL &&
    166      1.37       cgd 		      (qd->quirks & PCI_QUIRK_MULTIFUNCTION) != 0))
    167      1.37       cgd 			nfunctions = 8;
    168      1.37       cgd 		else
    169      1.37       cgd 			nfunctions = 1;
    170      1.10       cgd 
    171      1.10       cgd 		for (function = 0; function < nfunctions; function++) {
    172      1.18       cgd 			tag = pci_make_tag(pc, bus, device, function);
    173      1.18       cgd 			id = pci_conf_read(pc, tag, PCI_ID_REG);
    174      1.27       cgd 			csr = pci_conf_read(pc, tag, PCI_COMMAND_STATUS_REG);
    175      1.18       cgd 			class = pci_conf_read(pc, tag, PCI_CLASS_REG);
    176      1.18       cgd 			intr = pci_conf_read(pc, tag, PCI_INTERRUPT_REG);
    177      1.32       cgd 
    178      1.32       cgd 			/* Invalid vendor ID value? */
    179      1.33       cgd 			if (PCI_VENDOR(id) == PCI_VENDOR_INVALID)
    180      1.32       cgd 				continue;
    181      1.32       cgd 			/* XXX Not invalid, but we've done this ~forever. */
    182      1.32       cgd 			if (PCI_VENDOR(id) == 0)
    183      1.32       cgd 				continue;
    184      1.10       cgd 
    185      1.24   thorpej 			pa.pa_iot = iot;
    186      1.24   thorpej 			pa.pa_memt = memt;
    187      1.34  drochner 			pa.pa_dmat = sc->sc_dmat;
    188      1.18       cgd 			pa.pa_pc = pc;
    189  1.48.4.1        he 			pa.pa_bus = bus;
    190      1.10       cgd 			pa.pa_device = device;
    191      1.10       cgd 			pa.pa_function = function;
    192      1.10       cgd 			pa.pa_tag = tag;
    193      1.10       cgd 			pa.pa_id = id;
    194      1.10       cgd 			pa.pa_class = class;
    195      1.10       cgd 
    196      1.44   thorpej 			/*
    197      1.44   thorpej 			 * Set up memory, I/O enable, and PCI command flags
    198      1.44   thorpej 			 * as appropriate.
    199      1.44   thorpej 			 */
    200      1.44   thorpej 			pa.pa_flags = sc->sc_flags;
    201      1.44   thorpej 			if ((csr & PCI_COMMAND_IO_ENABLE) == 0)
    202      1.44   thorpej 				pa.pa_flags &= ~PCI_FLAGS_IO_ENABLED;
    203      1.44   thorpej 			if ((csr & PCI_COMMAND_MEM_ENABLE) == 0)
    204      1.44   thorpej 				pa.pa_flags &= ~PCI_FLAGS_MEM_ENABLED;
    205      1.27       cgd 
    206      1.18       cgd 			if (bus == 0) {
    207      1.18       cgd 				pa.pa_intrswiz = 0;
    208      1.18       cgd 				pa.pa_intrtag = tag;
    209      1.18       cgd 			} else {
    210      1.34  drochner 				pa.pa_intrswiz = sc->sc_intrswiz + device;
    211      1.34  drochner 				pa.pa_intrtag = sc->sc_intrtag;
    212      1.18       cgd 			}
    213      1.18       cgd 			pin = PCI_INTERRUPT_PIN(intr);
    214      1.18       cgd 			if (pin == PCI_INTERRUPT_PIN_NONE) {
    215      1.18       cgd 				/* no interrupt */
    216      1.18       cgd 				pa.pa_intrpin = 0;
    217      1.18       cgd 			} else {
    218      1.18       cgd 				/*
    219      1.18       cgd 				 * swizzle it based on the number of
    220      1.18       cgd 				 * busses we're behind and our device
    221      1.18       cgd 				 * number.
    222      1.18       cgd 				 */
    223      1.18       cgd 				pa.pa_intrpin =			/* XXX */
    224      1.18       cgd 				    ((pin + pa.pa_intrswiz - 1) % 4) + 1;
    225      1.18       cgd 			}
    226      1.18       cgd 			pa.pa_intrline = PCI_INTERRUPT_LINE(intr);
    227      1.18       cgd 
    228      1.10       cgd 			config_found_sm(self, &pa, pciprint, pcisubmatch);
    229      1.10       cgd 		}
    230      1.10       cgd 	}
    231      1.10       cgd }
    232       1.1   mycroft 
    233      1.34  drochner void
    234      1.34  drochner pciattach(parent, self, aux)
    235      1.34  drochner 	struct device *parent, *self;
    236      1.34  drochner 	void *aux;
    237      1.34  drochner {
    238      1.34  drochner 	struct pcibus_attach_args *pba = aux;
    239      1.34  drochner 	struct pci_softc *sc = (struct pci_softc *)self;
    240      1.43   thorpej 	int io_enabled, mem_enabled, mrl_enabled, mrm_enabled, mwi_enabled;
    241      1.43   thorpej 	const char *sep = "";
    242      1.34  drochner 
    243      1.34  drochner 	pci_attach_hook(parent, self, pba);
    244      1.34  drochner 	printf("\n");
    245      1.34  drochner 
    246      1.34  drochner 	io_enabled = (pba->pba_flags & PCI_FLAGS_IO_ENABLED);
    247      1.34  drochner 	mem_enabled = (pba->pba_flags & PCI_FLAGS_MEM_ENABLED);
    248      1.43   thorpej 	mrl_enabled = (pba->pba_flags & PCI_FLAGS_MRL_OKAY);
    249      1.43   thorpej 	mrm_enabled = (pba->pba_flags & PCI_FLAGS_MRM_OKAY);
    250      1.43   thorpej 	mwi_enabled = (pba->pba_flags & PCI_FLAGS_MWI_OKAY);
    251      1.34  drochner 
    252      1.34  drochner 	if (io_enabled == 0 && mem_enabled == 0) {
    253      1.34  drochner 		printf("%s: no spaces enabled!\n", self->dv_xname);
    254      1.34  drochner 		return;
    255      1.34  drochner 	}
    256      1.34  drochner 
    257      1.43   thorpej #define	PRINT(s)	do { printf("%s%s", sep, s); sep = ", "; } while (0)
    258      1.43   thorpej 
    259      1.34  drochner 	printf("%s: ", self->dv_xname);
    260      1.43   thorpej 
    261      1.34  drochner 	if (io_enabled)
    262      1.43   thorpej 		PRINT("i/o space");
    263      1.43   thorpej 	if (mem_enabled)
    264      1.43   thorpej 		PRINT("memory space");
    265      1.43   thorpej 	printf(" enabled");
    266      1.43   thorpej 
    267      1.43   thorpej 	if (mrl_enabled || mrm_enabled || mwi_enabled) {
    268      1.43   thorpej 		if (mrl_enabled)
    269      1.43   thorpej 			PRINT("rd/line");
    270      1.43   thorpej 		if (mrm_enabled)
    271      1.43   thorpej 			PRINT("rd/mult");
    272      1.43   thorpej 		if (mwi_enabled)
    273      1.43   thorpej 			PRINT("wr/inv");
    274      1.43   thorpej 		printf(" ok");
    275      1.34  drochner 	}
    276      1.43   thorpej 
    277      1.34  drochner 	printf("\n");
    278      1.43   thorpej 
    279      1.43   thorpej #undef PRINT
    280      1.34  drochner 
    281      1.34  drochner 	sc->sc_iot = pba->pba_iot;
    282      1.34  drochner 	sc->sc_memt = pba->pba_memt;
    283      1.34  drochner 	sc->sc_dmat = pba->pba_dmat;
    284      1.34  drochner 	sc->sc_pc = pba->pba_pc;
    285      1.34  drochner 	sc->sc_bus = pba->pba_bus;
    286      1.34  drochner 	sc->sc_maxndevs = pci_bus_maxdevs(pba->pba_pc, pba->pba_bus);
    287      1.34  drochner 	sc->sc_intrswiz = pba->pba_intrswiz;
    288      1.34  drochner 	sc->sc_intrtag = pba->pba_intrtag;
    289      1.34  drochner 	sc->sc_flags = pba->pba_flags;
    290      1.34  drochner 
    291      1.34  drochner 	pci_probe_bus(self);
    292      1.34  drochner }
    293      1.34  drochner 
    294       1.1   mycroft int
    295      1.10       cgd pciprint(aux, pnp)
    296       1.1   mycroft 	void *aux;
    297      1.21       cgd 	const char *pnp;
    298       1.1   mycroft {
    299      1.46  augustss 	struct pci_attach_args *pa = aux;
    300      1.10       cgd 	char devinfo[256];
    301      1.37       cgd 	const struct pci_quirkdata *qd;
    302       1.1   mycroft 
    303      1.10       cgd 	if (pnp) {
    304      1.10       cgd 		pci_devinfo(pa->pa_id, pa->pa_class, 1, devinfo);
    305      1.23  christos 		printf("%s at %s", devinfo, pnp);
    306      1.10       cgd 	}
    307      1.23  christos 	printf(" dev %d function %d", pa->pa_device, pa->pa_function);
    308      1.45       cgd 	if (pci_config_dump) {
    309      1.45       cgd 		printf(": ");
    310      1.45       cgd 		pci_conf_print(pa->pa_pc, pa->pa_tag, NULL);
    311      1.45       cgd 		if (!pnp)
    312      1.45       cgd 			pci_devinfo(pa->pa_id, pa->pa_class, 1, devinfo);
    313      1.45       cgd 		printf("%s at %s", devinfo, pnp ? pnp : "?");
    314      1.45       cgd 		printf(" dev %d function %d (", pa->pa_device, pa->pa_function);
    315      1.37       cgd #ifdef __i386__
    316      1.45       cgd 		printf("tag %#lx, intrtag %#lx, intrswiz %#lx, intrpin %#lx",
    317      1.45       cgd 		    *(long *)&pa->pa_tag, *(long *)&pa->pa_intrtag,
    318      1.45       cgd 		    (long)pa->pa_intrswiz, (long)pa->pa_intrpin);
    319      1.37       cgd #else
    320      1.45       cgd 		printf("tag %#lx, intrtag %#lx, intrswiz %#lx, intrpin %#lx",
    321      1.45       cgd 		    (long)pa->pa_tag, (long)pa->pa_intrtag, (long)pa->pa_intrswiz,
    322      1.45       cgd 		    (long)pa->pa_intrpin);
    323      1.36       cgd #endif
    324      1.45       cgd 		printf(", i/o %s, mem %s,",
    325      1.45       cgd 		    pa->pa_flags & PCI_FLAGS_IO_ENABLED ? "on" : "off",
    326      1.45       cgd 		    pa->pa_flags & PCI_FLAGS_MEM_ENABLED ? "on" : "off");
    327      1.45       cgd 		qd = pci_lookup_quirkdata(PCI_VENDOR(pa->pa_id),
    328      1.45       cgd 		    PCI_PRODUCT(pa->pa_id));
    329      1.45       cgd 		if (qd == NULL) {
    330      1.45       cgd 			printf(" no quirks");
    331      1.45       cgd 		} else {
    332      1.45       cgd 			bitmask_snprintf(qd->quirks,
    333      1.45       cgd 			    "\20\1multifn", devinfo, sizeof (devinfo));
    334      1.45       cgd 			printf(" quirks %s", devinfo);
    335      1.45       cgd 		}
    336      1.45       cgd 		printf(")");
    337      1.37       cgd 	}
    338       1.6   mycroft 	return (UNCONF);
    339       1.6   mycroft }
    340       1.6   mycroft 
    341       1.6   mycroft int
    342      1.26       cgd pcisubmatch(parent, cf, aux)
    343       1.6   mycroft 	struct device *parent;
    344      1.26       cgd 	struct cfdata *cf;
    345      1.26       cgd 	void *aux;
    346       1.6   mycroft {
    347       1.6   mycroft 	struct pci_attach_args *pa = aux;
    348       1.6   mycroft 
    349      1.14       cgd 	if (cf->pcicf_dev != PCI_UNK_DEV &&
    350      1.14       cgd 	    cf->pcicf_dev != pa->pa_device)
    351       1.6   mycroft 		return 0;
    352      1.14       cgd 	if (cf->pcicf_function != PCI_UNK_FUNCTION &&
    353      1.14       cgd 	    cf->pcicf_function != pa->pa_function)
    354       1.6   mycroft 		return 0;
    355      1.26       cgd 	return ((*cf->cf_attach->ca_match)(parent, cf, aux));
    356      1.40  drochner }
    357      1.40  drochner 
    358      1.40  drochner int
    359      1.40  drochner pci_get_capability(pc, tag, capid, offset, value)
    360      1.40  drochner 	pci_chipset_tag_t pc;
    361      1.40  drochner 	pcitag_t tag;
    362      1.40  drochner 	int capid;
    363      1.40  drochner 	int *offset;
    364      1.40  drochner 	pcireg_t *value;
    365      1.40  drochner {
    366      1.40  drochner 	pcireg_t reg;
    367      1.40  drochner 	unsigned int ofs;
    368      1.40  drochner 
    369      1.40  drochner 	reg = pci_conf_read(pc, tag, PCI_COMMAND_STATUS_REG);
    370      1.40  drochner 	if (!(reg & PCI_STATUS_CAPLIST_SUPPORT))
    371      1.40  drochner 		return (0);
    372      1.40  drochner 
    373      1.48    kleink 	/* Determine the Capability List Pointer register to start with. */
    374      1.47    kleink 	reg = pci_conf_read(pc, tag, PCI_BHLC_REG);
    375      1.47    kleink 	switch (PCI_HDRTYPE_TYPE(reg)) {
    376      1.47    kleink 	case 0:	/* standard device header */
    377      1.47    kleink 		ofs = PCI_CAPLISTPTR_REG;
    378      1.47    kleink 		break;
    379      1.47    kleink 	case 2:	/* PCI-CardBus Bridge header */
    380      1.47    kleink 		ofs = PCI_CARDBUS_CAPLISTPTR_REG;
    381      1.47    kleink 		break;
    382      1.47    kleink 	default:
    383      1.47    kleink 		return (0);
    384      1.47    kleink 	}
    385      1.47    kleink 
    386      1.47    kleink 	ofs = PCI_CAPLIST_PTR(pci_conf_read(pc, tag, ofs));
    387      1.40  drochner 	while (ofs != 0) {
    388      1.40  drochner #ifdef DIAGNOSTIC
    389      1.40  drochner 		if ((ofs & 3) || (ofs < 0x40))
    390      1.40  drochner 			panic("pci_get_capability");
    391      1.40  drochner #endif
    392      1.40  drochner 		reg = pci_conf_read(pc, tag, ofs);
    393      1.40  drochner 		if (PCI_CAPLIST_CAP(reg) == capid) {
    394      1.40  drochner 			if (offset)
    395      1.40  drochner 				*offset = ofs;
    396      1.40  drochner 			if (value)
    397      1.40  drochner 				*value = reg;
    398      1.40  drochner 			return (1);
    399      1.40  drochner 		}
    400      1.40  drochner 		ofs = PCI_CAPLIST_NEXT(reg);
    401      1.40  drochner 	}
    402      1.40  drochner 
    403      1.40  drochner 	return (0);
    404       1.1   mycroft }
    405