devinfo: Support PCI DBSF and ACPI handles for -p

When matching on a name of a device, match on ACPI handles and PCI
selectors in addition to device names.  This can be useful for
matching on devices without an attached driver.

For example: devinfo -p pci0:0:31:0

Reviewed by:	imp
Sponsored by:	Chelsio Communications
Differential Revision:	https://reviews.freebsd.org/D55673

2 files changed, 78 insertions, 2 deletions

diff --git a/usr.sbin/devinfo/devinfo.8 b/usr.sbin/devinfo/devinfo.8
index 8bf4f9d10e17..b8acdcf524ee 100644
--- a/usr.sbin/devinfo/devinfo.8
+++ b/usr.sbin/devinfo/devinfo.8
@@ -26,7 +26,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd August 28, 2025
+.Dd March 6, 2026
 .Dt DEVINFO 8
 .Os
 .Sh NAME
@@ -53,6 +53,26 @@ The following options are accepted:
 Display the path of
 .Ar dev
 back to the root of the device tree.
+.Ar dev
+can either be a device name,
+the absolute path of an ACPI handle
+.Po must begin with a
+.Dq \e
+.Pc ,
+or a PCI selector
+.Po
+either
+.Sy pci Ns Fa domain Ns : Ns Fa bus Ns : Ns Fa slot Ns : Ns Fa function
+or
+.Sy pci Ns Fa bus Ns : Ns Fa slot Ns : Ns Fa function
+.Pc .
+.Pp
+If
+.Fl v
+is specified,
+each device is output on a separate line including the device name and
+additional verbose information;
+otherwise, a space-separated list of device names is output.
 .It Fl r
 Causes hardware resource information
 .Pq such as IRQ, I/O ports, I/O memory addresses
diff --git a/usr.sbin/devinfo/devinfo.c b/usr.sbin/devinfo/devinfo.c
index 43d88481d903..bea082ba6285 100644
--- a/usr.sbin/devinfo/devinfo.c
+++ b/usr.sbin/devinfo/devinfo.c
@@ -275,13 +275,69 @@ print_device_path_entry(struct devinfo_dev *dev)
 		printf("\n");
 }
 
+/*
+ * This assumes the string to be compared in *cp is either space or
+ * nul terminated.
+ */
+static bool
+match_value(const char *cp, const char *name)
+{
+	const char *end;
+	size_t len;
+
+	end = strchr(cp, ' ');
+	if (end == NULL)
+		return (strcmp(cp, name) == 0);
+
+	if (end == cp)
+		return (false);
+
+	/* NB: strncmp(3) would return zero if name matches a prefix. */
+	len = end - cp;
+	return (strlen(name) == len && memcmp(name, cp, len) == 0);
+}
+
+static bool
+device_matches_name(struct devinfo_dev *dev, const char *name)
+{
+	const char *cp, *val;
+
+	if (strcmp(dev->dd_name, name) == 0)
+		return (true);
+
+	if (*dev->dd_location) {
+		/* Permit matches on the ACPI handle stored in location. */
+		if (name[0] == '\\' && (cp = strstr(dev->dd_location,
+		    "handle=\\")) != NULL) {
+			if (match_value(cp + strlen("handle="), name))
+				return (true);
+		}
+
+		/* Permit matches on the PCI dbsf stored in location. */
+		if (strncmp(name, "pci", strlen("pci")) == 0 &&
+		    (cp = strstr(dev->dd_location, "dbsf=pci")) != NULL) {
+			cp += strlen("dbsf=pci");
+			val = name + strlen("pci");
+			if (match_value(cp, val))
+				return (true);
+
+			/* Also match on pci<b>:<s>:<f> for domain 0. */
+			if (strncmp(cp, "0:", strlen("0:")) == 0 &&
+			    match_value(cp + strlen("0:"), val))
+				return (true);
+		}
+	}
+
+	return (false);
+}
+
 static int
 print_device_path(struct devinfo_dev *dev, void *xname)
 {
 	const char *name = xname;
 	int rv;
 
-	if (strcmp(dev->dd_name, name) == 0) {
+	if (device_matches_name(dev, name)) {
 		print_device_path_entry(dev);
 		return (1);
 	}