- Teach pciconf(8) to list the PCI capabilities supported by each device

  via a new -c flag to be used with -l.  Some simple parsing code is
  present for the following capabilities: Power Management, AGP, VPD,
  MSI, PCI-X, HyperTransport, Vendor-specific, EHCI Debug Port, PCI-PCI
  bridge subvendor ID, PCI-express, and MSI-X.
- Fix a few warnings in pciconf.c.
- Update some cruft in pciconf(8):
  - PCI 2.1 is no longer a revolutionary standard, and subvendor ID's are
    fairly common at this point, so reflect that.
  - Header type 2 is used for PCI-CardBus bridges.
  - Describe the -v option for -l after completing the basic -l description
    instead of disrupting the flow in the middle.

Reviewed by:	imp (partially)
MFC after:	1 week

5 files changed, 593 insertions, 46 deletions

diff --git a/usr.sbin/pciconf/Makefile b/usr.sbin/pciconf/Makefile
index d892a12..e57e736 100644
--- a/usr.sbin/pciconf/Makefile
+++ b/usr.sbin/pciconf/Makefile
@@ -2,6 +2,7 @@
 # $FreeBSD$
 
 PROG=	pciconf
+SRCS=	pciconf.c cap.c
 MAN=	pciconf.8
 
 CFLAGS+= -I${.CURDIR}/../../sys
diff --git a/usr.sbin/pciconf/cap.c b/usr.sbin/pciconf/cap.c
new file mode 100644
index 0000000..b0ec40f
--- /dev/null
+++ b/usr.sbin/pciconf/cap.c
@@ -0,0 +1,477 @@
+/*-
+ * Copyright (c) 2007 John Baldwin <jhb@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+static const char rcsid[] =
+  "$FreeBSD$";
+#endif /* not lint */
+
+#include <sys/types.h>
+
+#include <err.h>
+#include <stdio.h>
+#include <sys/agpio.h>
+#include <sys/pciio.h>
+
+#include <pci/agpreg.h>
+#include <dev/pci/pcireg.h>
+
+#include "pciconf.h"
+
+static void
+cap_power(int fd, struct pci_conf *p, uint8_t ptr)
+{
+	uint16_t cap, status;
+
+	cap = read_config(fd, &p->pc_sel, ptr + PCIR_POWER_CAP, 2);
+	status = read_config(fd, &p->pc_sel, ptr + PCIR_POWER_STATUS, 2);
+	printf("powerspec %d  supports D0%s%s D3  current D%d",
+	    cap & PCIM_PCAP_SPEC,
+	    cap & PCIM_PCAP_D1SUPP ? " D1" : "",
+	    cap & PCIM_PCAP_D2SUPP ? " D2" : "",
+	    status & PCIM_PSTAT_DMASK);
+}
+
+static void
+cap_agp(int fd, struct pci_conf *p, uint8_t ptr)
+{
+	uint32_t status, command;
+
+	status = read_config(fd, &p->pc_sel, ptr + AGP_STATUS, 4);
+	command = read_config(fd, &p->pc_sel, ptr + AGP_CAPID, 4);
+	printf("AGP ");
+	if (AGP_MODE_GET_MODE_3(status)) {
+		printf("v3 ");
+		if (AGP_MODE_GET_RATE(status) & AGP_MODE_V3_RATE_8x)
+			printf("8x ");
+		if (AGP_MODE_GET_RATE(status) & AGP_MODE_V3_RATE_4x)
+			printf("4x ");
+	} else {
+		if (AGP_MODE_GET_RATE(status) & AGP_MODE_V2_RATE_4x)
+			printf("4x ");
+		if (AGP_MODE_GET_RATE(status) & AGP_MODE_V2_RATE_2x)
+			printf("2x ");
+		if (AGP_MODE_GET_RATE(status) & AGP_MODE_V2_RATE_1x)
+			printf("1x ");
+	}
+	if (AGP_MODE_GET_SBA(status))
+		printf("SBA ");
+	if (AGP_MODE_GET_AGP(command)) {
+		printf("enabled at ");
+		if (AGP_MODE_GET_MODE_3(command)) {
+			printf("v3 ");
+			switch (AGP_MODE_GET_RATE(command)) {
+			case AGP_MODE_V3_RATE_8x:
+				printf("8x ");
+				break;
+			case AGP_MODE_V3_RATE_4x:
+				printf("4x ");
+				break;
+			}
+		} else
+			switch (AGP_MODE_GET_RATE(command)) {
+			case AGP_MODE_V2_RATE_4x:
+				printf("4x ");
+				break;
+			case AGP_MODE_V2_RATE_2x:
+				printf("2x ");
+				break;
+			case AGP_MODE_V2_RATE_1x:
+				printf("1x ");
+				break;
+			}
+		if (AGP_MODE_GET_SBA(command))
+			printf("SBA ");
+	} else
+		printf("disabled");
+}
+
+static void
+cap_vpd(int fd, struct pci_conf *p, uint8_t ptr)
+{
+
+	printf("VPD");
+}
+
+static void
+cap_msi(int fd, struct pci_conf *p, uint8_t ptr)
+{
+	uint16_t ctrl;
+	int msgnum;
+
+	ctrl = read_config(fd, &p->pc_sel, ptr + PCIR_MSI_CTRL, 2);
+	msgnum = 1 << ((ctrl & PCIM_MSICTRL_MMC_MASK) >> 1);
+	printf("MSI supports %d message%s%s%s ", msgnum,
+	    (msgnum == 1) ? "" : "s",
+	    (ctrl & PCIM_MSICTRL_64BIT) ? ", 64 bit" : "",
+	    (ctrl & PCIM_MSICTRL_VECTOR) ? ", vector masks" : "");
+	if (ctrl & PCIM_MSICTRL_MSI_ENABLE) {
+		msgnum = 1 << ((ctrl & PCIM_MSICTRL_MME_MASK) >> 4);
+		printf("enabled with %d message%s", msgnum,
+		    (msgnum == 1) ? "" : "s");
+	}
+}
+
+static void
+cap_pcix(int fd, struct pci_conf *p, uint8_t ptr)
+{
+	uint32_t status;
+	int comma, max_splits, max_burst_read;
+
+	status = read_config(fd, &p->pc_sel, ptr + PCIXR_STATUS, 4);
+	printf("PCI-X ");
+	if (status & PCIXM_STATUS_64BIT)
+		printf("64-bit ");
+	if ((p->pc_hdr & PCIM_HDRTYPE) == 1)
+		printf("bridge ");
+	printf("supports");
+	comma = 0;
+	if (status & PCIXM_STATUS_133CAP) {
+		printf("%s 133MHz", comma ? "," : "");
+		comma = 1;
+	}
+	if (status & PCIXM_STATUS_266CAP) {
+		printf("%s 266MHz", comma ? "," : "");
+		comma = 1;
+	}
+	if (status & PCIXM_STATUS_533CAP) {
+		printf("%s 533MHz", comma ? "," : "");
+		comma = 1;
+	}
+	if ((p->pc_hdr & PCIM_HDRTYPE) == 1)
+		return;
+	switch (status & PCIXM_STATUS_MAX_READ) {
+	case PCIXM_STATUS_MAX_READ_512:
+		max_burst_read = 512;
+		break;
+	case PCIXM_STATUS_MAX_READ_1024:
+		max_burst_read = 1024;
+		break;
+	case PCIXM_STATUS_MAX_READ_2048:
+		max_burst_read = 2048;
+		break;
+	case PCIXM_STATUS_MAX_READ_4096:
+		max_burst_read = 4096;
+		break;
+	}
+	switch (status & PCIXM_STATUS_MAX_SPLITS) {
+	case PCIXM_STATUS_MAX_SPLITS_1:
+		max_splits = 1;
+		break;
+	case PCIXM_STATUS_MAX_SPLITS_2:
+		max_splits = 2;
+		break;
+	case PCIXM_STATUS_MAX_SPLITS_3:
+		max_splits = 3;
+		break;
+	case PCIXM_STATUS_MAX_SPLITS_4:
+		max_splits = 4;
+		break;
+	case PCIXM_STATUS_MAX_SPLITS_8:
+		max_splits = 8;
+		break;
+	case PCIXM_STATUS_MAX_SPLITS_12:
+		max_splits = 12;
+		break;
+	case PCIXM_STATUS_MAX_SPLITS_16:
+		max_splits = 16;
+		break;
+	case PCIXM_STATUS_MAX_SPLITS_32:
+		max_splits = 32;
+		break;
+	}
+	printf("%s %d burst read, %d split transaction%s", comma ? "," : "",
+	    max_burst_read, max_splits, max_splits == 1 ? "" : "s");
+}
+
+static void
+cap_ht(int fd, struct pci_conf *p, uint8_t ptr)
+{
+	uint32_t reg;
+	uint16_t command;
+
+	command = read_config(fd, &p->pc_sel, ptr + PCIR_HT_COMMAND, 2);
+	printf("HT ");
+	if ((command & 0xe000) == PCIM_HTCAP_SLAVE)
+		printf("slave");
+	else if ((command & 0xe000) == PCIM_HTCAP_HOST)
+		printf("host");
+	else
+		switch (command & PCIM_HTCMD_CAP_MASK) {
+		case PCIM_HTCAP_SWITCH:
+			printf("switch");
+			break;
+		case PCIM_HTCAP_INTERRUPT:
+			printf("interrupt");
+			break;
+		case PCIM_HTCAP_REVISION_ID:
+			printf("revision ID");
+			break;
+		case PCIM_HTCAP_UNITID_CLUMPING:
+			printf("unit ID clumping");
+			break;
+		case PCIM_HTCAP_EXT_CONFIG_SPACE:
+			printf("extended config space");
+			break;
+		case PCIM_HTCAP_ADDRESS_MAPPING:
+			printf("address mapping");
+			break;
+		case PCIM_HTCAP_MSI_MAPPING:
+			printf("MSI address window %s at 0x",
+			    command & PCIM_HTCMD_MSI_ENABLE ? "enabled" :
+			    "disabled");
+			reg = read_config(fd, &p->pc_sel,
+			    ptr + PCIR_HTMSI_ADDRESS_HI, 4);
+			if (reg != 0)
+				printf("%08x", reg);
+			reg = read_config(fd, &p->pc_sel,
+			    ptr + PCIR_HTMSI_ADDRESS_LO, 4);
+			printf("%08x", reg);
+			break;
+		case PCIM_HTCAP_DIRECT_ROUTE:
+			printf("direct route");
+			break;
+		case PCIM_HTCAP_VCSET:
+			printf("VC set");
+			break;
+		case PCIM_HTCAP_RETRY_MODE:
+			printf("retry mode");
+			break;
+		default:
+			printf("unknown %02x", command);
+			break;
+		}
+}
+
+static void
+cap_vendor(int fd, struct pci_conf *p, uint8_t ptr)
+{
+	uint8_t length;
+
+	length = read_config(fd, &p->pc_sel, ptr + PCIR_VENDOR_LENGTH, 1);
+	printf("vendor (length %d)", length);
+	if (p->pc_vendor == 0x8086) {
+		/* Intel */
+		uint8_t version;
+
+		version = read_config(fd, &p->pc_sel, ptr + PCIR_VENDOR_DATA,
+		    1);
+		printf(" Intel cap %d version %d", version >> 4, version & 0xf);
+		if (version >> 4 == 1 && length == 12) {
+			/* Feature Detection */
+			uint32_t fvec;
+			int comma;
+
+			comma = 0;
+			fvec = read_config(fd, &p->pc_sel, ptr +
+			    PCIR_VENDOR_DATA + 5, 4);
+			printf("\n\t\t features:");
+			if (fvec & (1 << 0)) {
+				printf(" AMT");
+				comma = 1;
+			}
+			fvec = read_config(fd, &p->pc_sel, ptr +
+			    PCIR_VENDOR_DATA + 1, 4);
+			if (fvec & (1 << 21)) {
+				printf("%s Quick Resume", comma ? "," : "");
+				comma = 1;
+			}
+			if (fvec & (1 << 18)) {
+				printf("%s SATA RAID-5", comma ? "," : "");
+				comma = 1;
+			}
+			if (fvec & (1 << 9)) {
+				printf("%s Mobile", comma ? "," : "");
+				comma = 1;
+			}
+			if (fvec & (1 << 7)) {
+				printf("%s 6 PCI-e x1 slots", comma ? "," : "");
+				comma = 1;
+			} else {
+				printf("%s 4 PCI-e x1 slots", comma ? "," : "");
+				comma = 1;
+			}
+			if (fvec & (1 << 5)) {
+				printf("%s SATA RAID-0/1/10", comma ? "," : "");
+				comma = 1;
+			}
+			if (fvec & (1 << 3)) {
+				printf("%s SATA AHCI", comma ? "," : "");
+				comma = 1;
+			}
+		}
+	}
+}
+
+static void
+cap_debug(int fd, struct pci_conf *p, uint8_t ptr)
+{
+	uint16_t debug_port;
+
+	debug_port = read_config(fd, &p->pc_sel, ptr + PCIR_DEBUG_PORT, 2);
+	printf("EHCI Debug Port at offset 0x%x in map 0x%x", debug_port &
+	    PCIM_DEBUG_PORT_OFFSET, PCIR_BAR(debug_port >> 13));
+}
+
+static void
+cap_subvendor(int fd, struct pci_conf *p, uint8_t ptr)
+{
+	uint32_t id;
+
+	id = read_config(fd, &p->pc_sel, ptr + PCIR_SUBVENDCAP_ID, 4);
+	printf("PCI Bridge card=0x%08x", id);
+}
+
+static void
+cap_express(int fd, struct pci_conf *p, uint8_t ptr)
+{
+	uint16_t flags;
+
+	flags = read_config(fd, &p->pc_sel, ptr + PCIR_EXPRESS_FLAGS, 2);
+	printf("PCI-Express %d ", flags & PCIM_EXP_FLAGS_VERSION);
+	switch (flags & PCIM_EXP_FLAGS_TYPE) {
+	case PCIM_EXP_TYPE_ENDPOINT:
+		printf("endpoint");
+		break;
+	case PCIM_EXP_TYPE_LEGACY_ENDPOINT:
+		printf("legacy endpoint");
+		break;
+	case PCIM_EXP_TYPE_ROOT_PORT:
+		printf("root port");
+		break;
+	case PCIM_EXP_TYPE_UPSTREAM_PORT:
+		printf("upstream port");
+		break;
+	case PCIM_EXP_TYPE_DOWNSTREAM_PORT:
+		printf("downstream port");
+		break;
+	case PCIM_EXP_TYPE_PCI_BRIDGE:
+		printf("PCI bridge");
+		break;
+	default:
+		printf("type %d", (flags & PCIM_EXP_FLAGS_TYPE) >> 8);
+		break;
+	}
+	if (flags & PCIM_EXP_FLAGS_IRQ)
+		printf(" IRQ %d", (flags & PCIM_EXP_FLAGS_IRQ) >> 17);
+}
+
+static void
+cap_msix(int fd, struct pci_conf *p, uint8_t ptr)
+{
+	uint32_t val;
+	uint16_t ctrl;
+	int msgnum, table_bar, pba_bar;
+
+	ctrl = read_config(fd, &p->pc_sel, ptr + PCIR_MSIX_CTRL, 2);
+	msgnum = (ctrl & PCIM_MSIXCTRL_TABLE_SIZE) + 1;
+	val = read_config(fd, &p->pc_sel, ptr + PCIR_MSIX_TABLE, 4);
+	table_bar = PCIR_BAR(val & PCIM_MSIX_BIR_MASK);
+	val = read_config(fd, &p->pc_sel, ptr + PCIR_MSIX_PBA, 4);
+	pba_bar = PCIR_BAR(val & PCIM_MSIX_BIR_MASK);	
+	printf("MSI-X supports %d message%s ", msgnum,
+	    (msgnum == 1) ? "" : "s");
+	if (table_bar == pba_bar)
+		printf("in map 0x%x", table_bar);
+	else
+		printf("in maps 0x%x and 0x%x", table_bar, pba_bar);
+	if (ctrl & PCIM_MSIXCTRL_MSIX_ENABLE)
+		printf(" enabled");
+}
+
+void
+list_caps(int fd, struct pci_conf *p)
+{
+	uint16_t cmd;
+	uint8_t ptr, cap;
+
+	/* Are capabilities present for this device? */
+	cmd = read_config(fd, &p->pc_sel, PCIR_STATUS, 2);
+	if (!(cmd & PCIM_STATUS_CAPPRESENT))
+		return;
+
+	switch (p->pc_hdr & PCIM_HDRTYPE) {
+	case 0:
+	case 1:
+		ptr = PCIR_CAP_PTR;
+		break;
+	case 2:
+		ptr = PCIR_CAP_PTR_2;
+		break;
+	default:
+		errx(1, "list_caps: bad header type");
+	}
+
+	/* Walk the capability list. */
+	ptr = read_config(fd, &p->pc_sel, ptr, 1);
+	while (ptr != 0 && ptr != 0xff) {
+		cap = read_config(fd, &p->pc_sel, ptr + PCICAP_ID, 1);
+		printf("    cap %02x[%02x] = ", cap, ptr);
+		switch (cap) {
+		case PCIY_PMG:
+			cap_power(fd, p, ptr);
+			break;
+		case PCIY_AGP:
+			cap_agp(fd, p, ptr);
+			break;
+		case PCIY_VPD:
+			cap_vpd(fd, p, ptr);
+			break;
+		case PCIY_MSI:
+			cap_msi(fd, p, ptr);
+			break;
+		case PCIY_PCIX:
+			cap_pcix(fd, p, ptr);
+			break;
+		case PCIY_HT:
+			cap_ht(fd, p, ptr);
+			break;
+		case PCIY_VENDOR:
+			cap_vendor(fd, p, ptr);
+			break;
+		case PCIY_DEBUG:
+			cap_debug(fd, p, ptr);
+			break;
+		case PCIY_SUBVENDOR:
+			cap_subvendor(fd, p, ptr);
+			break;
+		case PCIY_EXPRESS:
+			cap_express(fd, p, ptr);
+			break;
+		case PCIY_MSIX:
+			cap_msix(fd, p, ptr);
+			break;
+		default:
+			printf("unknown");
+			break;
+		}
+		printf("\n");
+		ptr = read_config(fd, &p->pc_sel, ptr + PCICAP_NEXTPTR, 1);
+	}
+}
diff --git a/usr.sbin/pciconf/pciconf.8 b/usr.sbin/pciconf/pciconf.8
index ea41bba..524cf1e 100644
--- a/usr.sbin/pciconf/pciconf.8
+++ b/usr.sbin/pciconf/pciconf.8
@@ -33,7 +33,7 @@
 .Nd diagnostic utility for the PCI bus
 .Sh SYNOPSIS
 .Nm
-.Fl l Op Fl v
+.Fl l Op Fl cv
 .Nm
 .Fl a Ar selector
 .Nm
@@ -61,13 +61,6 @@ bar0@pci0:5:0: class=0x000100 card=0x00000000 chip=0x88c15333 rev=0x00 hdr=0x00
 none0@pci0:6:0: class=0x020000 card=0x00000000 chip=0x802910ec rev=0x00 hdr=0x00
 .Ed
 .Pp
-If the
-.Fl v
-option is supplied,
-.Nm
-will attempt to load the vendor/device information database, and print
-vendor, device, class and subclass identification strings for each device.
-.Pp
 The first column gives the
 device name, unit number, and
 .Ar selector .
@@ -86,12 +79,7 @@ The third column gives the contents of the subvendorid register, introduced
 in revision 2.1 of the
 .Tn PCI
 standard.
-It is 0 for most current (2.0)
-.Tn PCI
-cards, but is supposed to be loaded with a unique card identification code
-in newly developed
-.Tn PCI
-cards.
+Note that it will be 0 for older cards.
 The field consists of the card ID in the upper
 half and the card vendor ID in the lower half of the value.
 .Pp
@@ -101,11 +89,16 @@ It consists of two fields, identifying the chip and
 its vendor, as above.
 The fifth column prints the chip's revision.
 The sixth column describes the header type.
-Currently assigned header types are 0 for all devices except
+Currently assigned header types include 0 for most devices,
+1 for 
 .Tn PCI
 to
 .Tn PCI
-bridges, and 1 for such bridge chips.
+bridges, and 2 for
+.Tn PCI
+to
+.Tn CardBus
+bridges.
 If the most significant bit
 of the header type register is set for
 function 0 of a
@@ -115,6 +108,30 @@ device, it is a
 device, which contains several (similar or independent) functions on
 one chip.
 .Pp
+If the
+.Fl c
+option is supplied,
+.Nm
+will list any capabilities supported by each device.
+Each capability will be enumerated via a line in the following format:
+.Bd -literal
+    cap 10[40] = PCI-Express 1 root port
+.Ed
+.Pp
+The first value after the
+.Dq cap
+prefix is the capability ID in hexadecimal.
+The second value in the square brackets is the offset of the capability
+in config space in hexadecimal.
+The format of the text after the equals sign is capability-specific.
+.Pp
+If the
+.Fl v
+option is supplied,
+.Nm
+will attempt to load the vendor/device information database, and print
+vendor, device, class and subclass identification strings for each device.
+.Pp
 All invocations of
 .Nm
 except for
diff --git a/usr.sbin/pciconf/pciconf.c b/usr.sbin/pciconf/pciconf.c
index 8fc3146..a42435c 100644
--- a/usr.sbin/pciconf/pciconf.c
+++ b/usr.sbin/pciconf/pciconf.c
@@ -35,6 +35,7 @@ static const char rcsid[] =
 #include <sys/types.h>
 #include <sys/fcntl.h>
 
+#include <ctype.h>
 #include <err.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -46,6 +47,7 @@ static const char rcsid[] =
 #include <dev/pci/pcireg.h>
 
 #include "pathnames.h"
+#include "pciconf.h"
 
 struct pci_device_info
 {
@@ -64,10 +66,10 @@ struct pci_vendor_info
 
 TAILQ_HEAD(,pci_vendor_info)	pci_vendors;
 
-static void list_devs(int vendors);
+static void list_devs(int verbose, int caps);
 static void list_verbose(struct pci_conf *p);
-static char *guess_class(struct pci_conf *p);
-static char *guess_subclass(struct pci_conf *p);
+static const char *guess_class(struct pci_conf *p);
+static const char *guess_subclass(struct pci_conf *p);
 static int load_vendors(void);
 static void readit(const char *, const char *, int);
 static void writeit(const char *, const char *, const char *, int);
@@ -76,10 +78,10 @@ static void chkattached(const char *, int);
 static int exitstatus = 0;
 
 static void
-usage()
+usage(void)
 {
 	fprintf(stderr, "%s\n%s\n%s\n%s\n",
-		"usage: pciconf -l [-v]",
+		"usage: pciconf -l [-cv]",
 		"       pciconf -a selector",
 		"       pciconf -r [-b | -h] selector addr[:addr2]",
 		"       pciconf -w [-b | -h] selector addr value");
@@ -90,17 +92,21 @@ int
 main(int argc, char **argv)
 {
 	int c;
-	int listmode, readmode, writemode, attachedmode, verbose;
+	int listmode, readmode, writemode, attachedmode, caps, verbose;
 	int byte, isshort;
 
-	listmode = readmode = writemode = attachedmode = verbose = byte = isshort = 0;
+	listmode = readmode = writemode = attachedmode = caps = verbose = byte = isshort = 0;
 
-	while ((c = getopt(argc, argv, "alrwbhv")) != -1) {
+	while ((c = getopt(argc, argv, "aclrwbhv")) != -1) {
 		switch(c) {
 		case 'a':
 			attachedmode = 1;
 			break;
 
+		case 'c':
+			caps = 1;
+			break;
+
 		case 'l':
 			listmode = 1;
 			break;
@@ -137,7 +143,7 @@ main(int argc, char **argv)
 		usage();
 
 	if (listmode) {
-		list_devs(verbose);
+		list_devs(verbose, caps);
 	} else if (attachedmode) {
 		chkattached(argv[optind],
 		       byte ? 1 : isshort ? 2 : 4);
@@ -155,7 +161,7 @@ main(int argc, char **argv)
 }
 
 static void
-list_devs(int verbose)
+list_devs(int verbose, int caps)
 {
 	int fd;
 	struct pci_conf_io pc;
@@ -165,7 +171,7 @@ list_devs(int verbose)
 	if (verbose)
 		load_vendors();
 
-	fd = open(_PATH_DEVPCI, O_RDONLY, 0);
+	fd = open(_PATH_DEVPCI, caps ? O_RDWR : O_RDONLY, 0);
 	if (fd < 0)
 		err(1, "%s", _PATH_DEVPCI);
 
@@ -212,6 +218,8 @@ list_devs(int verbose)
 			       p->pc_revid, p->pc_hdr);
 			if (verbose)
 				list_verbose(p);
+			if (caps)
+				list_caps(fd, p);
 		}
 	} while (pc.status == PCI_GETCONF_MORE_DEVS);
 
@@ -223,11 +231,11 @@ list_verbose(struct pci_conf *p)
 {
 	struct pci_vendor_info	*vi;
 	struct pci_device_info	*di;
-	char *dp;
+	const char *dp;
 
 	TAILQ_FOREACH(vi, &pci_vendors, link) {
 		if (vi->id == p->pc_vendor) {
-			printf("    vendor   = '%s'\n", vi->desc);
+			printf("    vendor     = '%s'\n", vi->desc);
 			break;
 		}
 	}
@@ -236,15 +244,15 @@ list_verbose(struct pci_conf *p)
 	} else {
 		TAILQ_FOREACH(di, &vi->devs, link) {
 			if (di->id == p->pc_device) {
-				printf("    device   = '%s'\n", di->desc);
+				printf("    device     = '%s'\n", di->desc);
 				break;
 			}
 		}
 	}
 	if ((dp = guess_class(p)) != NULL)
-		printf("    class    = %s\n", dp);
+		printf("    class      = %s\n", dp);
 	if ((dp = guess_subclass(p)) != NULL)
-		printf("    subclass = %s\n", dp);
+		printf("    subclass   = %s\n", dp);
 }
 
 /*
@@ -254,7 +262,7 @@ static struct
 {
 	int	class;
 	int	subclass;
-	char	*desc;
+	const char *desc;
 } pci_nomatch_tab[] = {
 	{PCIC_OLD,		-1,			"old"},
 	{PCIC_OLD,		PCIS_OLD_NONVGA,	"non-VGA display device"},
@@ -337,7 +345,7 @@ static struct
 	{0, 0,		NULL}
 };
 
-static char *
+static const char *
 guess_class(struct pci_conf *p)
 {
 	int	i;
@@ -349,7 +357,7 @@ guess_class(struct pci_conf *p)
 	return(NULL);
 }
 
-static char *
+static const char *
 guess_subclass(struct pci_conf *p)
 {
 	int	i;
@@ -365,7 +373,7 @@ guess_subclass(struct pci_conf *p)
 static int
 load_vendors(void)
 {
-	char *dbf;
+	const char *dbf;
 	FILE *db;
 	struct pci_vendor_info *cv;
 	struct pci_device_info *cd;
@@ -458,6 +466,20 @@ load_vendors(void)
 	return(error);
 }
 
+uint32_t
+read_config(int fd, struct pcisel *sel, long reg, int width)
+{
+	struct pci_io pi;
+
+	pi.pi_sel = *sel;
+	pi.pi_reg = reg;
+	pi.pi_width = width;
+
+	if (ioctl(fd, PCIOCREAD, &pi) < 0)
+		err(1, "ioctl(PCIOCREAD)");
+
+	return (pi.pi_data);
+}
 
 static struct pcisel
 getsel(const char *str)
@@ -496,16 +518,8 @@ getsel(const char *str)
 static void
 readone(int fd, struct pcisel *sel, long reg, int width)
 {
-	struct pci_io pi;
-
-	pi.pi_sel = *sel;
-	pi.pi_reg = reg;
-	pi.pi_width = width;
-
-	if (ioctl(fd, PCIOCREAD, &pi) < 0)
-		err(1, "ioctl(PCIOCREAD)");
 
-	printf("%0*x", width*2, pi.pi_data);
+	printf("%0*x", width*2, read_config(fd, sel, reg, width));
 }
 
 static void
@@ -559,7 +573,7 @@ writeit(const char *name, const char *reg, const char *data, int width)
 }
 
 static void
-chkattached (const char *name, int width)
+chkattached(const char *name, int width)
 {
 	int fd;
 	struct pci_io pi;
diff --git a/usr.sbin/pciconf/pciconf.h b/usr.sbin/pciconf/pciconf.h
new file mode 100644
index 0000000..81d94f5
--- /dev/null
+++ b/usr.sbin/pciconf/pciconf.h
@@ -0,0 +1,38 @@
+/*-
+ * Copyright (c) 2007 John Baldwin <jhb@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef __PCICONF_H__
+#define	__PCICONF_H__
+
+void	list_caps(int fd, struct pci_conf *p);
+uint32_t read_config(int fd, struct pcisel *sel, long reg, int width);
+
+#endif