selftests: add basic netdevsim devlink flash testing

Utilizes the devlink flash code.
Suggested-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/drivers/net/netdevsim/devlink.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+lib_dir=$(dirname $0)/../../../net/forwarding
+
+ALL_TESTS="fw_flash_test"
+NUM_NETIFS=0
+source $lib_dir/lib.sh
+
+BUS_ADDR=10
+PORT_COUNT=4
+DEV_NAME=netdevsim$BUS_ADDR
+SYSFS_NET_DIR=/sys/bus/netdevsim/devices/$DEV_NAME/net/
+DEBUGFS_DIR=/sys/kernel/debug/netdevsim/$DEV_NAME/
+DL_HANDLE=netdevsim/$DEV_NAME
+
+fw_flash_test()
+{
+	RET=0
+
+	devlink dev flash $DL_HANDLE file dummy
+	check_err $? "Failed to flash with status updates on"
+
+	echo "n"> $DEBUGFS_DIR/fw_update_status
+	check_err $? "Failed to disable status updates"
+
+	devlink dev flash $DL_HANDLE file dummy
+	check_err $? "Failed to flash with status updates off"
+
+	log_test "fw flash test"
+}
+
+setup_prepare()
+{
+	modprobe netdevsim
+	echo "$BUS_ADDR $PORT_COUNT" > /sys/bus/netdevsim/new_device
+	while [ ! -d $SYSFS_NET_DIR ] ; do :; done
+}
+
+cleanup()
+{
+	pre_cleanup
+	echo "$BUS_ADDR" > /sys/bus/netdevsim/del_device
+	modprobe -r netdevsim
+}
+
+trap cleanup EXIT
+
+setup_prepare
+
+tests_run
+
+exit $EXIT_STATUS