selftests: firmware: skip unsupported custom firmware fallback tests

Ignore custom firmware loading and cancellation tests on older
kernel releases, which do not support this feature.

Fixes: 061132d2b9 ("test_firmware: add test custom fallback trigger")
Reviewed-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Luis R. Rodriguez <mcgrof@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/firmware/fw_fallback.sh

@@ -86,6 +86,11 @@ load_fw_cancel()
 
 load_fw_custom()
 {
+	if [ ! -e "$DIR"/trigger_custom_fallback ]; then
+		echo "$0: custom fallback trigger not present, ignoring test" >&2
+		return 1
+	fi
+
 	local name="$1"
 	local file="$2"
 
@@ -108,11 +113,17 @@ load_fw_custom()
 
 	# Wait for request to finish.
 	wait
+	return 0
 }
 
 
 load_fw_custom_cancel()
 {
+	if [ ! -e "$DIR"/trigger_custom_fallback ]; then
+		echo "$0: canceling custom fallback trigger not present, ignoring test" >&2
+		return 1
+	fi
+
 	local name="$1"
 	local file="$2"
 
@@ -133,6 +144,7 @@ load_fw_custom_cancel()
 
 	# Wait for request to finish.
 	wait
+	return 0
 }
 
 load_fw_fallback_with_child()
@@ -227,21 +239,23 @@ else
 	echo "$0: cancelling fallback mechanism works"
 fi
 
-load_fw_custom "$NAME" "$FW"
+if load_fw_custom "$NAME" "$FW" ; then
 	if ! diff -q "$FW" /dev/test_firmware >/dev/null ; then
 		echo "$0: firmware was not loaded" >&2
 		exit 1
 	else
 		echo "$0: custom fallback loading mechanism works"
 	fi
+fi
 
-load_fw_custom_cancel "nope-$NAME" "$FW"
+if load_fw_custom_cancel "nope-$NAME" "$FW" ; then
 	if diff -q "$FW" /dev/test_firmware >/dev/null ; then
 		echo "$0: firmware was expected to be cancelled" >&2
 		exit 1
 	else
 		echo "$0: cancelling custom fallback mechanism works"
 	fi
+fi
 
 set +e
 load_fw_fallback_with_child "nope-signal-$NAME" "$FW"