kselftest: Add test to verify probe of devices from discoverable buses

Add a new test to verify that a list of expected devices from
discoverable buses (ie USB, PCI) have been successfully instantiated and
probed by a driver.

The per-platform list of expected devices is selected from the ones
under the boards/ directory based on the DT compatible or the DMI IDs.

Signed-off-by: "Nícolas F. R. A. Prado" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: nfraprado

tools/testing/selftests/Makefile

@@ -13,6 +13,7 @@ TARGETS += core
 TARGETS += cpufreq
 TARGETS += cpu-hotplug
 TARGETS += damon
+TARGETS += devices
 TARGETS += dmabuf-heaps
 TARGETS += drivers/dma-buf
 TARGETS += drivers/s390x/uvdevice

tools/testing/selftests/devices/Makefile

@@ -0,0 +1,4 @@
+TEST_PROGS := test_discoverable_devices.py
+TEST_FILES := boards ksft.py
+
+include ../lib.mk

tools/testing/selftests/devices/ksft.py

@@ -0,0 +1,90 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (c) 2023 Collabora Ltd
+#
+# Kselftest helpers for outputting in KTAP format. Based on kselftest.h.
+#
+
+import sys
+
+ksft_cnt = {"pass": 0, "fail": 0, "skip": 0}
+ksft_num_tests = 0
+ksft_test_number = 1
+
+KSFT_PASS = 0
+KSFT_FAIL = 1
+KSFT_SKIP = 4
+
+
+def print_header():
+    print("TAP version 13")
+
+
+def set_plan(num_tests):
+    global ksft_num_tests
+    ksft_num_tests = num_tests
+    print("1..{}".format(num_tests))
+
+
+def print_cnts():
+    print(
+        f"# Totals: pass:{ksft_cnt['pass']} fail:{ksft_cnt['fail']} xfail:0 xpass:0 skip:{ksft_cnt['skip']} error:0"
+    )
+
+
+def print_msg(msg):
+    print(f"# {msg}")
+
+
+def _test_print(result, description, directive=None):
+    if directive:
+        directive_str = f"# {directive}"
+    else:
+        directive_str = ""
+
+    global ksft_test_number
+    print(f"{result} {ksft_test_number} {description} {directive_str}")
+    ksft_test_number += 1
+
+
+def test_result_pass(description):
+    _test_print("ok", description)
+    ksft_cnt["pass"] += 1
+
+
+def test_result_fail(description):
+    _test_print("not ok", description)
+    ksft_cnt["fail"] += 1
+
+
+def test_result_skip(description):
+    _test_print("ok", description, "SKIP")
+    ksft_cnt["skip"] += 1
+
+
+def test_result(condition, description=""):
+    if condition:
+        test_result_pass(description)
+    else:
+        test_result_fail(description)
+
+
+def finished():
+    if ksft_cnt["pass"] == ksft_num_tests:
+        exit_code = KSFT_PASS
+    else:
+        exit_code = KSFT_FAIL
+
+    print_cnts()
+
+    sys.exit(exit_code)
+
+
+def exit_fail():
+    print_cnts()
+    sys.exit(KSFT_FAIL)
+
+
+def exit_pass():
+    print_cnts()
+    sys.exit(KSFT_PASS)