From 1592bb3c795141872467a97e04ef36e531079444 Mon Sep 17 00:00:00 2001
From: jhibbits <jhibbits@FreeBSD.org>
Date: Sun, 28 Aug 2016 21:31:21 +0000
Subject: [PATCH] Check all compatible strings on uart devices in powerpc

Summary:
Some device trees put "fsl,ns16650" first in the compatible list.  This causes
the probe code to choke, even though the device is compatible with ns16650, and
has it listed later in the tree.

Reviewed by:	nwhitehorn
MFC after:	1 week
Differential Revision: https://reviews.freebsd.org/D7676
---
 sys/dev/ofw/ofw_bus_subr.c      | 28 +++++++++++++++++++++++++---
 sys/dev/ofw/ofw_bus_subr.h      |  1 +
 sys/dev/uart/uart_cpu_powerpc.c |  8 ++++----
 3 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/sys/dev/ofw/ofw_bus_subr.c b/sys/dev/ofw/ofw_bus_subr.c
index d6a04d8f65e6..1c80106ceb61 100644
--- a/sys/dev/ofw/ofw_bus_subr.c
+++ b/sys/dev/ofw/ofw_bus_subr.c
@@ -45,6 +45,8 @@ __FBSDID("$FreeBSD$");
 
 #include "ofw_bus_if.h"
 
+#define	OFW_COMPAT_LEN	255
+
 int
 ofw_bus_gen_setup_devinfo(struct ofw_bus_devinfo *obd, phandle_t node)
 {
@@ -178,7 +180,8 @@ ofw_bus_status_okay(device_t dev)
 }
 
 static int
-ofw_bus_node_is_compatible(const char *compat, int len, const char *onecompat)
+ofw_bus_node_is_compatible_int(const char *compat, int len,
+    const char *onecompat)
 {
 	int onelen, l, ret;
 
@@ -202,6 +205,25 @@ ofw_bus_node_is_compatible(const char *compat, int len, const char *onecompat)
 	return (ret);
 }
 
+int
+ofw_bus_node_is_compatible(phandle_t node, const char *compatstr)
+{
+	char compat[OFW_COMPAT_LEN];
+	int len, rv;
+
+	if ((len = OF_getproplen(node, "compatible")) <= 0)
+		return (0);
+
+	bzero(compat, OFW_COMPAT_LEN);
+
+	if (OF_getprop(node, "compatible", compat, OFW_COMPAT_LEN) < 0)
+		return (0);
+
+	rv = ofw_bus_node_is_compatible_int(compat, len, compatstr);
+
+	return (rv);
+}
+
 int
 ofw_bus_is_compatible(device_t dev, const char *onecompat)
 {
@@ -219,7 +241,7 @@ ofw_bus_is_compatible(device_t dev, const char *onecompat)
 	if ((len = OF_getproplen(node, "compatible")) <= 0)
 		return (0);
 
-	return (ofw_bus_node_is_compatible(compat, len, onecompat));
+	return (ofw_bus_node_is_compatible_int(compat, len, onecompat));
 }
 
 int
@@ -689,7 +711,7 @@ ofw_bus_find_compatible(phandle_t node, const char *onecompat)
 	for (child = OF_child(node); child != 0; child = OF_peer(child)) {
 		len = OF_getprop_alloc(child, "compatible", 1, &compat);
 		if (len >= 0) {
-			ret = ofw_bus_node_is_compatible(compat, len,
+			ret = ofw_bus_node_is_compatible_int(compat, len,
 			    onecompat);
 			free(compat, M_OFWPROP);
 			if (ret != 0)
diff --git a/sys/dev/ofw/ofw_bus_subr.h b/sys/dev/ofw/ofw_bus_subr.h
index 146009cac91b..6532a1661991 100644
--- a/sys/dev/ofw/ofw_bus_subr.h
+++ b/sys/dev/ofw/ofw_bus_subr.h
@@ -107,6 +107,7 @@ phandle_t ofw_bus_find_iparent(phandle_t);
 /* Helper routine for checking compat prop */
 int ofw_bus_is_compatible(device_t, const char *);
 int ofw_bus_is_compatible_strict(device_t, const char *);
+int ofw_bus_node_is_compatible(phandle_t, const char *);
 
 /* 
  * Helper routine to search a list of compat properties.  The table is
diff --git a/sys/dev/uart/uart_cpu_powerpc.c b/sys/dev/uart/uart_cpu_powerpc.c
index 8d9840577eb9..d3155b08c54f 100644
--- a/sys/dev/uart/uart_cpu_powerpc.c
+++ b/sys/dev/uart/uart_cpu_powerpc.c
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 #include <machine/bus.h>
 #include <machine/ofw_machdep.h>
 
+#include <dev/ofw/ofw_bus_subr.h>
 #include <dev/ofw/openfirm.h>
 #include <dev/uart/uart.h>
 #include <dev/uart/uart_cpu.h>
@@ -163,14 +164,13 @@ uart_cpu_getdev(int devtype, struct uart_devinfo *di)
 		return (ENXIO);
 	if (strcmp(buf, "serial") != 0)
 		return (ENXIO);
-	if (OF_getprop(input, "compatible", buf, sizeof(buf)) == -1)
-		return (ENXIO);
 
-	if (strncmp(buf, "chrp,es", 7) == 0) {
+	if (ofw_bus_node_is_compatible(input, "chrp,es")) {
 		class = &uart_z8530_class;
 		di->bas.regshft = 4;
 		di->bas.chan = 1;
-	} else if (strcmp(buf,"ns16550") == 0 || strcmp(buf,"ns8250") == 0) {
+	} else if (ofw_bus_node_is_compatible(input,"ns16550") ||
+	    ofw_bus_node_is_compatible(input,"ns8250")) {
 		class = &uart_ns8250_class;
 		di->bas.regshft = 0;
 		di->bas.chan = 0;