1 files changed, 89 insertions, 0 deletions

diff --git a/tools/testing/selftests/firmware/fw_userhelper.sh b/tools/testing/selftests/firmware/fw_userhelper.sh
new file mode 100644
index 000000000000..6efbade12139
--- /dev/null
+++ b/tools/testing/selftests/firmware/fw_userhelper.sh
@@ -0,0 +1,89 @@
+#!/bin/sh
+# This validates that the kernel will fall back to using the user helper
+# to load firmware it can't find on disk itself. We must request a firmware
+# that the kernel won't find, and any installed helper (e.g. udev) also
+# won't find so that we can do the load ourself manually.
+set -e
+
+modprobe test_firmware
+
+DIR=/sys/devices/virtual/misc/test_firmware
+
+OLD_TIMEOUT=$(cat /sys/class/firmware/timeout)
+
+FWPATH=$(mktemp -d)
+FW="$FWPATH/test-firmware.bin"
+
+test_finish()
+{
+        echo "$OLD_TIMEOUT" >/sys/class/firmware/timeout
+        rm -f "$FW"
+        rmdir "$FWPATH"
+}
+
+load_fw()
+{
+        local name="$1"
+        local file="$2"
+
+        # This will block until our load (below) has finished.
+        echo -n "$name" >"$DIR"/trigger_request &
+
+        # Give kernel a chance to react.
+        local timeout=10
+        while [ ! -e "$DIR"/"$name"/loading ]; do
+                sleep 0.1
+                timeout=$(( $timeout - 1 ))
+                if [ "$timeout" -eq 0 ]; then
+                        echo "$0: firmware interface never appeared" >&2
+                        exit 1
+                fi
+        done
+
+        echo 1 >"$DIR"/"$name"/loading
+        cat "$file" >"$DIR"/"$name"/data
+        echo 0 >"$DIR"/"$name"/loading
+
+        # Wait for request to finish.
+        wait
+}
+
+trap "test_finish" EXIT
+
+# This is an unlikely real-world firmware content. :)
+echo "ABCD0123" >"$FW"
+NAME=$(basename "$FW")
+
+# Test failure when doing nothing (timeout works).
+echo 1 >/sys/class/firmware/timeout
+echo -n "$NAME" >"$DIR"/trigger_request
+if diff -q "$FW" /dev/test_firmware >/dev/null ; then
+        echo "$0: firmware was not expected to match" >&2
+        exit 1
+else
+        echo "$0: timeout works"
+fi
+
+# Put timeout high enough for us to do work but not so long that failures
+# slow down this test too much.
+echo 4 >/sys/class/firmware/timeout
+
+# Load this script instead of the desired firmware.
+load_fw "$NAME" "$0"
+if diff -q "$FW" /dev/test_firmware >/dev/null ; then
+        echo "$0: firmware was not expected to match" >&2
+        exit 1
+else
+        echo "$0: firmware comparison works"
+fi
+
+# Do a proper load, which should work correctly.
+load_fw "$NAME" "$FW"
+if ! diff -q "$FW" /dev/test_firmware >/dev/null ; then
+        echo "$0: firmware was not loaded" >&2
+        exit 1
+else
+        echo "$0: user helper firmware loading works"
+fi
+
+exit 0