drm/panic: Compile KUnit tests as module

Fix dependency of the panic-helper KUnit tests on CONFIG_DRM_KUNIT_TEST=y
and make them build as a module. Export the necessary interfaces from the
panic helpers iff the KUnit framework has been enabled.

Select DRM_PANIC_HELPER from DRM_KUNIT_TEST to meet the dependencies of
the panic-helper tests.

It is now possible to run the tests by modprobe-ing drm_panic_helper_test
at runtime.

v5:
- clear test description with drm_panic_helper_clear_description() (Sashiko)
v3:
- clean up after each test case (Sashiko)
v2:
- fix parameter order in decl of drm_panic_helper_draw_screen_qr()
  (Sashiko)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patch.msgid.link/20260911124540.279841-15-tzimmermann@suse.de

2 files changed, 18 insertions, 4 deletions

diff --git a/drivers/gpu/drm/tests/Makefile b/drivers/gpu/drm/tests/Makefile
index e7193b49cf91..42207df1d1c8 100644
--- a/drivers/gpu/drm/tests/Makefile
+++ b/drivers/gpu/drm/tests/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_DRM_KUNIT_TEST) += \
 	drm_managed_test.o \
 	drm_mm_test.o \
 	drm_modes_test.o \
+	drm_panic_helper_test.o \
 	drm_plane_helper_test.o \
 	drm_probe_helper_test.o \
 	drm_rect_test.o \
diff --git a/drivers/gpu/drm/tests/drm_panic_helper_test.c b/drivers/gpu/drm/tests/drm_panic_helper_test.c
index e6befe0f1c83..d0366e10d8c1 100644
--- a/drivers/gpu/drm/tests/drm_panic_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_panic_helper_test.c
@@ -6,13 +6,17 @@
  * KUNIT tests for DRM panic helpers
  */
 
-#include <drm/drm_fourcc.h>
-#include <drm/drm_panic.h>
+#include <linux/highmem.h>
+#include <linux/units.h>
+#include <linux/vmalloc.h>
 
 #include <kunit/test.h>
 
-#include <linux/units.h>
-#include <linux/vmalloc.h>
+#include <drm/drm_fourcc.h>
+#include <drm/drm_panic.h>
+#include <drm/drm_panic_helper.h>
+
+MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
 
 static void drm_panic_check_color_byte(struct kunit *test, u8 b)
 {
@@ -86,6 +90,11 @@ static int drm_test_panic_init(struct kunit *test)
 	return 0;
 }
 
+static void drm_test_panic_exit(struct kunit *test)
+{
+	drm_panic_helper_clear_description();
+}
+
 /*
  * Test drawing the panic screen, using a memory mapped framebuffer
  * Set the whole buffer to 0xa5, and then check that all pixels have been
@@ -229,7 +238,11 @@ static struct kunit_case drm_panic_screen_user_test[] = {
 static struct kunit_suite drm_panic_helper_suite = {
 	.name = "drm_panic_helper",
 	.init = drm_test_panic_init,
+	.exit = drm_test_panic_exit,
 	.test_cases = drm_panic_screen_user_test,
 };
 
 kunit_test_suite(drm_panic_helper_suite);
+
+MODULE_DESCRIPTION("KUnit test suite for DRM panic handling");
+MODULE_LICENSE("GPL");