[PATCH 49/59] drm/amd/display: Test SW init and fini

[WHAT]
Add KUnit tests for dm_sw_init() on an ASIC without a DMUB, and for the
DMUB bounding box release in dm_sw_fini().

[HOW]
An ASIC without DMUB support makes dm_dmub_sw_init() return early. The
bounding box allocation is left without a buffer object, which
amdgpu_bo_free_kernel() short-circuits.

Assisted-by: Copilot:Claude-Opus-5 GPT-5.6-Sol
Reviewed-by: Bhawanpreet Lakha <[email protected]>
Signed-off-by: Alex Hung <[email protected]>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  3 +-
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h |  1 +
 .../display/amdgpu_dm/tests/amdgpu_dm_test.c  | 51 +++++++++++++++++++
 3 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 128b12a945fc..8b4d01d97ea4 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1079,7 +1079,7 @@ STATIC_IFN_KUNIT int load_dmcu_fw(struct amdgpu_device *adev)
 }
 EXPORT_IF_KUNIT(load_dmcu_fw);
 
-static int dm_sw_init(struct amdgpu_ip_block *ip_block)
+STATIC_IFN_KUNIT int dm_sw_init(struct amdgpu_ip_block *ip_block)
 {
 	struct amdgpu_device *adev = ip_block->adev;
 	int r;
@@ -1100,6 +1100,7 @@ static int dm_sw_init(struct amdgpu_ip_block *ip_block)
 
 	return load_dmcu_fw(adev);
 }
+EXPORT_IF_KUNIT(dm_sw_init);
 
 STATIC_IFN_KUNIT int dm_sw_fini(struct amdgpu_ip_block *ip_block)
 {
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index 858fe967046b..80da5a378d73 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -1254,6 +1254,7 @@ void mmhub_read_system_context(struct amdgpu_device *adev,
 			       struct dc_phy_addr_space_config *pa_config);
 int amdgpu_dm_init_power_module(struct amdgpu_display_manager *dm);
 int load_dmcu_fw(struct amdgpu_device *adev);
+int dm_sw_init(struct amdgpu_ip_block *ip_block);
 #endif
 
 #endif /* __AMDGPU_DM_H__ */
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_test.c b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_test.c
index f0cd2de97faf..8ad6cf0eaa6c 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_test.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_test.c
@@ -3654,6 +3654,54 @@ static void dm_test_load_dmcu_fw_missing_firmware(struct kunit *test)
 	KUNIT_EXPECT_NULL(test, adev->dm.fw_dmcu);
 }
 
+/* Tests for dm_sw_init() and dm_sw_fini() */
+
+/**
+ * dm_test_sw_init_no_dmub - Test software init on an ASIC without a DMUB
+ * @test: The KUnit test context
+ */
+static void dm_test_sw_init_no_dmub(struct kunit *test)
+{
+	struct amdgpu_device *adev = dm_kunit_alloc_adev(test);
+	struct amdgpu_ip_block ip_block = { .adev = adev };
+
+	adev->asic_type = CHIP_BONAIRE;
+
+	KUNIT_EXPECT_EQ(test, dm_sw_init(&ip_block), 0);
+	KUNIT_ASSERT_NOT_NULL(test, adev->dm.cgs_device);
+	KUNIT_EXPECT_TRUE(test, list_empty(&adev->dm.da_list));
+
+	/* amdgpu_cgs_destroy_device() is not exported and is a plain kfree(). */
+	kfree(adev->dm.cgs_device);
+}
+
+/**
+ * dm_test_sw_fini_releases_bounding_box - Test the DMUB bounding box is released
+ * @test: The KUnit test context
+ */
+static void dm_test_sw_fini_releases_bounding_box(struct kunit *test)
+{
+	struct amdgpu_device *adev = dm_kunit_alloc_adev(test);
+	struct amdgpu_ip_block ip_block = { .adev = adev };
+	struct dal_allocation *da;
+	void *bb;
+
+	bb = kunit_kzalloc(test, sizeof(*da), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, bb);
+	/* Freed by dm_sw_fini(), so it must not be KUnit-managed. */
+	da = kzalloc_obj(*da);
+	KUNIT_ASSERT_NOT_NULL(test, da);
+
+	INIT_LIST_HEAD(&adev->dm.da_list);
+	da->cpu_ptr = bb;
+	list_add(&da->list, &adev->dm.da_list);
+	adev->dm.bb_from_dmub = bb;
+
+	KUNIT_EXPECT_EQ(test, dm_sw_fini(&ip_block), 0);
+	KUNIT_EXPECT_NULL(test, adev->dm.bb_from_dmub);
+	KUNIT_EXPECT_TRUE(test, list_empty(&adev->dm.da_list));
+}
+
 static struct kunit_case amdgpu_dm_tests[] = {
 	/* Simple DM callbacks */
 	KUNIT_CASE(dm_test_wait_for_idle),
@@ -3840,6 +3888,9 @@ static struct kunit_case amdgpu_dm_tests[] = {
 	KUNIT_CASE(dm_test_load_dmcu_fw_unsupported),
 	KUNIT_CASE(dm_test_load_dmcu_fw_raven),
 	KUNIT_CASE(dm_test_load_dmcu_fw_missing_firmware),
+	/* dm_sw_init / dm_sw_fini */
+	KUNIT_CASE(dm_test_sw_init_no_dmub),
+	KUNIT_CASE(dm_test_sw_fini_releases_bounding_box),
 	{}
 };
 
-- 
2.43.0