[PATCH 07/70] drm/amd/display: add fused IO KUnit coverage

[Wayne Lin <Wayne.Lin@amd.com>]

From: Alex Hung <alex.hung@amd.com>

[WHAT]
Add KUnit coverage for the DMUB fused IO helpers: the
dm_dmub_aux_fused_io_callback() NULL-argument guard and the
abort_fused_io() no-DMUB-service path.

Assisted-by: Copilot:Claude-Opus-4.8 GPT-5.5
Reviewed-by: Bhawanpreet Lakha <bhawanpreet.lakha@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Wayne Lin <wayne.lin@amd.com>
---
 .../amd/display/amdgpu_dm/amdgpu_dm_dmub.c    |  3 +-
 .../amd/display/amdgpu_dm/amdgpu_dm_dmub.h    |  8 +++
 .../amdgpu_dm/tests/amdgpu_dm_dmub_test.c     | 52 +++++++++++++++++++
 3 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_dmub.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_dmub.c
index d2148b62073d..b6f09a687969 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_dmub.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_dmub.c
@@ -831,7 +831,7 @@ int amdgpu_dm_process_dmub_aux_transfer_sync(
 	return ret;
 }
 
-static void abort_fused_io(
+STATIC_IFN_KUNIT void abort_fused_io(
 		struct dc_context *ctx,
 		const struct dmub_cmd_fused_request *request
 )
@@ -845,6 +845,7 @@ static void abort_fused_io(
 	io->request = *request;
 	dm_execute_dmub_cmd(ctx, &command, DM_DMUB_WAIT_TYPE_NO_WAIT);
 }
+EXPORT_IF_KUNIT(abort_fused_io);
 
 static bool execute_fused_io(
 		struct amdgpu_device *dev,
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_dmub.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_dmub.h
index a4a03e40ec37..ba50e1af80c1 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_dmub.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_dmub.h
@@ -65,4 +65,12 @@ int dm_init_microcode(struct amdgpu_device *adev);
 #define FIRMWARE_RAVEN_DMCU		"amdgpu/raven_dmcu.bin"
 #define FIRMWARE_NAVI12_DMCU		"amdgpu/navi12_dmcu.bin"
 
+#if IS_ENABLED(CONFIG_DRM_AMD_DC_KUNIT_TEST)
+struct dc_context;
+struct dmub_cmd_fused_request;
+
+void abort_fused_io(struct dc_context *ctx,
+		    const struct dmub_cmd_fused_request *request);
+#endif
+
 #endif /* AMDGPU_DM_AMDGPU_DM_DMUB_H_ */
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_dmub_test.c b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_dmub_test.c
index bae34436c89e..c3bd93b15d0a 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_dmub_test.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_dmub_test.c
@@ -396,6 +396,22 @@ static void dm_test_dmub_aux_fused_io_callback_max_ddc_line(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, reply_ddc_line, notify_ddc_line);
 }
 
+/**
+ * dm_test_dmub_aux_fused_io_callback_null_args - Test the NULL-argument guard
+ * @test: The KUnit test context
+ *
+ * Passing a NULL device triggers the defensive guard (an ASSERT that maps to
+ * WARN_ON_ONCE in this build) and returns early without dereferencing the
+ * arguments. The call must not crash.
+ */
+static void dm_test_dmub_aux_fused_io_callback_null_args(struct kunit *test)
+{
+	struct dmub_notification notify = {};
+
+	/* Must not crash; guard hits ASSERT (WARN_ON_ONCE) and returns. */
+	dm_dmub_aux_fused_io_callback(NULL, &notify);
+}
+
 /* Tests for dm_get_default_ips_mode() */
 
 /**
@@ -916,6 +932,39 @@ static void dm_test_init_microcode_unsupported_asic(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, dm_init_microcode(adev), 0);
 }
 
+/* Tests for abort_fused_io() */
+
+/**
+ * dm_test_abort_fused_io_no_dmub_srv - Test fused IO abort is a safe no-op without DMUB service
+ * @test: The KUnit test context
+ *
+ * abort_fused_io() builds an abort command and submits it via
+ * dm_execute_dmub_cmd(); with no DC DMUB service the submission fails
+ * silently and the call must not crash.
+ */
+static void dm_test_abort_fused_io_no_dmub_srv(struct kunit *test)
+{
+	struct amdgpu_device *adev;
+	struct dc_context *ctx;
+	struct dmub_cmd_fused_request *req;
+
+	adev = kunit_kzalloc(test, sizeof(*adev), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, adev);
+
+	ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx);
+
+	req = kunit_kzalloc(test, sizeof(*req), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, req);
+
+	spin_lock_init(&adev->dm.dmub_lock);
+	ctx->driver_context = adev;
+	ctx->dmub_srv = NULL;
+
+	/* Must not crash. */
+	abort_fused_io(ctx, req);
+}
+
 static struct kunit_case amdgpu_dm_dmub_tests[] = {
 	/* dm_register_dmub_notify_callback() */
 	KUNIT_CASE(dm_test_register_dmub_notify_callback_null_callback),
@@ -930,6 +979,7 @@ static struct kunit_case amdgpu_dm_dmub_tests[] = {
 	/* dm_dmub_aux_fused_io_callback() */
 	KUNIT_CASE(dm_test_dmub_aux_fused_io_callback_copies_reply_and_completes),
 	KUNIT_CASE(dm_test_dmub_aux_fused_io_callback_max_ddc_line),
+	KUNIT_CASE(dm_test_dmub_aux_fused_io_callback_null_args),
 	/* dm_get_default_ips_mode() */
 	KUNIT_CASE(dm_test_get_default_ips_mode_dcn35),
 	KUNIT_CASE(dm_test_get_default_ips_mode_dcn351),
@@ -959,6 +1009,8 @@ static struct kunit_case amdgpu_dm_dmub_tests[] = {
 	KUNIT_CASE(dm_test_dmub_sw_init_unsupported_asic),
 	/* dm_init_microcode() */
 	KUNIT_CASE(dm_test_init_microcode_unsupported_asic),
+	/* abort_fused_io() */
+	KUNIT_CASE(dm_test_abort_fused_io_no_dmub_srv),
 	{}
 };
 
-- 
2.43.0