test_firmware: add simple firmware firmware test library

We'll expland on this later, for now just add basic module checker.
While at it, move this all to use /bin/bash as we'll have much more
flexibility with it.
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tools/testing/selftests/firmware/fw_fallback.sh

-#!/bin/sh
+#!/bin/bash
 # SPDX-License-Identifier: GPL-2.0
 # This validates that the kernel will fall back to using the fallback mechanism
 # to load firmware it can't find on disk itself. We must request a firmware
@@ -6,9 +6,10 @@
 # won't find so that we can do the load ourself manually.
 set -e
 
-modprobe test_firmware
+TEST_DIR=$(dirname $0)
+source $TEST_DIR/fw_lib.sh
 
-DIR=/sys/devices/virtual/misc/test_firmware
+check_mods
 
 # CONFIG_FW_LOADER_USER_HELPER has a sysfs class under /sys/class/firmware/
 # These days no one enables CONFIG_FW_LOADER_USER_HELPER so check for that

tools/testing/selftests/firmware/fw_filesystem.sh

-#!/bin/sh
+#!/bin/bash
 # SPDX-License-Identifier: GPL-2.0
 # This validates that the kernel will load firmware out of its list of
 # firmware locations on disk. Since the user helper does similar work,
@@ -6,24 +6,10 @@
 # know so we can be sure we're not accidentally testing the user helper.
 set -e
 
-DIR=/sys/devices/virtual/misc/test_firmware
 TEST_DIR=$(dirname $0)
+source $TEST_DIR/fw_lib.sh
 
-test_modprobe()
-{
-	if [ ! -d $DIR ]; then
-		echo "$0: $DIR not present"
-		echo "You must have the following enabled in your kernel:"
-		cat $TEST_DIR/config
-		exit 1
-	fi
-}
-
-trap "test_modprobe" EXIT
-
-if [ ! -d $DIR ]; then
-	modprobe test_firmware
-fi
+check_mods
 
 # CONFIG_FW_LOADER_USER_HELPER has a sysfs class under /sys/class/firmware/
 # These days most distros enable CONFIG_FW_LOADER_USER_HELPER but disable

tools/testing/selftests/firmware/fw_lib.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# Library of helpers for test scripts.
+set -e
+
+DIR=/sys/devices/virtual/misc/test_firmware
+
+PROC_CONFIG="/proc/config.gz"
+TEST_DIR=$(dirname $0)
+
+print_reqs_exit()
+{
+	echo "You must have the following enabled in your kernel:" >&2
+	cat $TEST_DIR/config >&2
+	exit 1
+}
+
+test_modprobe()
+{
+	if [ ! -d $DIR ]; then
+		print_reqs_exit
+	fi
+}
+
+check_mods()
+{
+	trap "test_modprobe" EXIT
+	if [ ! -d $DIR ]; then
+		modprobe test_firmware
+	fi
+	if [ ! -f $PROC_CONFIG ]; then
+		if modprobe configs 2>/dev/null; then
+			echo "Loaded configs module"
+			if [ ! -f $PROC_CONFIG ]; then
+				echo "You must have the following enabled in your kernel:" >&2
+				cat $TEST_DIR/config >&2
+				echo "Resorting to old heuristics" >&2
+			fi
+		else
+			echo "Failed to load configs module, using old heuristics" >&2
+		fi
+	fi
+}