[PATCH v2 3/3] kselftest: Add new test for detecting unprobed Devicetree devices

From: Nícolas F. R. A. Prado
Date: Thu Aug 17 2023 - 19:37:27 EST


Introduce a new kselftest to detect devices that were declared in the
Devicetree, and are expected to be probed by a driver, but weren't.

The test uses two lists: a list of compatibles that can match a
Devicetree device to a driver, and a list of compatibles that should be
ignored. The first is automatically generated by the
dt-extract-compatibles script, and is run as part of building this test.
The list of compatibles to ignore is a hand-crafted list to capture the
few exceptions of compatibles that are expected to match a driver but
not be bound to it.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx>

---

Changes in v2:
- Switched output to be in KTAP format
- Changed Makefile to make use of the dt-extract-compatibles instead of
the Coccinelle script
- Dropped compatibles from compatible_ignore_list that are now already
filtered out by extraction script
- Added early exit if /proc/device-tree is not present

tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/dt/.gitignore | 1 +
tools/testing/selftests/dt/Makefile | 21 +++++
.../selftests/dt/compatible_ignore_list | 1 +
tools/testing/selftests/dt/ktap_helpers.sh | 57 +++++++++++++
.../selftests/dt/test_unprobed_devices.sh | 79 +++++++++++++++++++
6 files changed, 160 insertions(+)
create mode 100644 tools/testing/selftests/dt/.gitignore
create mode 100644 tools/testing/selftests/dt/Makefile
create mode 100644 tools/testing/selftests/dt/compatible_ignore_list
create mode 100644 tools/testing/selftests/dt/ktap_helpers.sh
create mode 100755 tools/testing/selftests/dt/test_unprobed_devices.sh

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 42806add0114..e8823097698c 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -18,6 +18,7 @@ TARGETS += drivers/dma-buf
TARGETS += drivers/s390x/uvdevice
TARGETS += drivers/net/bonding
TARGETS += drivers/net/team
+TARGETS += dt
TARGETS += efivarfs
TARGETS += exec
TARGETS += fchmodat2
diff --git a/tools/testing/selftests/dt/.gitignore b/tools/testing/selftests/dt/.gitignore
new file mode 100644
index 000000000000..f6476c9f2884
--- /dev/null
+++ b/tools/testing/selftests/dt/.gitignore
@@ -0,0 +1 @@
+compatible_list
diff --git a/tools/testing/selftests/dt/Makefile b/tools/testing/selftests/dt/Makefile
new file mode 100644
index 000000000000..62dc00ee4978
--- /dev/null
+++ b/tools/testing/selftests/dt/Makefile
@@ -0,0 +1,21 @@
+PY3 = $(shell which python3 2>/dev/null)
+
+ifneq ($(PY3),)
+
+TEST_PROGS := test_unprobed_devices.sh
+TEST_GEN_FILES := compatible_list
+TEST_FILES := compatible_ignore_list ktap_helpers.sh
+
+include ../lib.mk
+
+$(OUTPUT)/compatible_list:
+ $(top_srcdir)/scripts/dtc/dt-extract-compatibles -d $(top_srcdir) > $@
+
+else
+
+all: no_py3_warning
+
+no_py3_warning:
+ @echo "Missing python3. This test will be skipped."
+
+endif
diff --git a/tools/testing/selftests/dt/compatible_ignore_list b/tools/testing/selftests/dt/compatible_ignore_list
new file mode 100644
index 000000000000..1323903feca9
--- /dev/null
+++ b/tools/testing/selftests/dt/compatible_ignore_list
@@ -0,0 +1 @@
+simple-mfd
diff --git a/tools/testing/selftests/dt/ktap_helpers.sh b/tools/testing/selftests/dt/ktap_helpers.sh
new file mode 100644
index 000000000000..27e89a31e602
--- /dev/null
+++ b/tools/testing/selftests/dt/ktap_helpers.sh
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (c) 2023 Collabora Ltd
+#
+# Helpers for outputting in KTAP format
+#
+KTAP_TESTNO=1
+
+ktap_print_header() {
+ echo "TAP version 13"
+}
+
+ktap_set_plan() {
+ num_tests="$1"
+
+ echo "1..$num_tests"
+}
+
+ktap_skip_all() {
+ echo -n "1..0 # SKIP "
+ echo $@
+}
+
+__ktap_test() {
+ result="$1"
+ description="$2"
+ directive="$3" # optional
+
+ local directive_str=
+ [[ ! -z "$directive" ]] && directive_str="# $directive"
+
+ echo $result $KTAP_TESTNO $description $directive_str
+
+ KTAP_TESTNO=$((KTAP_TESTNO+1))
+}
+
+ktap_test_pass() {
+ description="$1"
+
+ result="ok"
+ __ktap_test "$result" "$description"
+}
+
+ktap_test_skip() {
+ description="$1"
+
+ result="ok"
+ directive="SKIP"
+ __ktap_test "$result" "$description" "$directive"
+}
+
+ktap_test_fail() {
+ description="$1"
+
+ result="not ok"
+ __ktap_test "$result" "$description"
+}
diff --git a/tools/testing/selftests/dt/test_unprobed_devices.sh b/tools/testing/selftests/dt/test_unprobed_devices.sh
new file mode 100755
index 000000000000..b523767cdbfb
--- /dev/null
+++ b/tools/testing/selftests/dt/test_unprobed_devices.sh
@@ -0,0 +1,79 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (c) 2023 Collabora Ltd
+#
+# Based on Frank Rowand's dt_stat script.
+#
+# This script tests for devices that were declared on the Devicetree and are
+# expected to bind to a driver, but didn't.
+#
+# To achieve this, two lists are used:
+# * a list of the compatibles that can be matched by a Devicetree node
+# * a list of compatibles that should be ignored
+#
+
+DIR="$(dirname $(readlink -f "$0"))"
+
+source "${DIR}"/ktap_helpers.sh
+
+PDT=/proc/device-tree/
+COMPAT_LIST="${DIR}"/compatible_list
+IGNORE_LIST="${DIR}"/compatible_ignore_list
+
+KSFT_PASS=0
+KSFT_FAIL=1
+KSFT_SKIP=4
+
+ktap_print_header
+
+if [[ ! -d "${PDT}" ]]; then
+ ktap_skip_all "${PDT} doesn't exist."
+ exit "${KSFT_SKIP}"
+fi
+
+nodes_compatible=$(
+ for node_compat in $(find ${PDT} -name compatible); do
+ node=$(dirname "${node_compat}")
+ # Check if node is available
+ [[ -e "${node}"/status && $(tr -d '\000' < "${node}"/status) != "okay" ]] && continue
+ echo "${node}" | sed -e 's|\/proc\/device-tree||'
+ done | sort
+ )
+
+nodes_dev_bound=$(
+ IFS=$'\n'
+ for uevent in $(find /sys/devices -name uevent); do
+ if [[ -d "$(dirname "${uevent}")"/driver ]]; then
+ grep '^OF_FULLNAME=' "${uevent}" | sed -e 's|OF_FULLNAME=||'
+ fi
+ done
+ )
+
+num_tests=$(echo ${nodes_compatible} | wc -w)
+ktap_set_plan "${num_tests}"
+
+retval="${KSFT_PASS}"
+for node in ${nodes_compatible}; do
+ if ! echo "${nodes_dev_bound}" | grep -E -q "(^| )${node}( |\$)"; then
+ compatibles=$(tr '\000' '\n' < "${PDT}"/"${node}"/compatible)
+
+ for compatible in ${compatibles}; do
+ if grep -x -q "${compatible}" "${IGNORE_LIST}"; then
+ continue
+ fi
+
+ if grep -x -q "${compatible}" "${COMPAT_LIST}"; then
+ ktap_test_fail "${node}"
+ retval="${KSFT_FAIL}"
+ continue 2
+ fi
+ done
+ ktap_test_skip "${node}"
+ else
+ ktap_test_pass "${node}"
+ fi
+
+done
+
+exit "${retval}"
--
2.41.0