[PATCH 08/13] drm/xe/tests: Add GuC KLV helpers basic tests

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

We will be making more extensive use of GuC KLV helpers. Add simple
tests to ensure the helpers are working as expected.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
---
 .../drm/xe/tests/xe_guc_klv_helpers_kunit.c   | 99 +++++++++++++++++++
 drivers/gpu/drm/xe/xe_guc_klv_helpers.c       |  4 +
 2 files changed, 103 insertions(+)
 create mode 100644 drivers/gpu/drm/xe/tests/xe_guc_klv_helpers_kunit.c

diff --git a/drivers/gpu/drm/xe/tests/xe_guc_klv_helpers_kunit.c b/drivers/gpu/drm/xe/tests/xe_guc_klv_helpers_kunit.c
new file mode 100644
index 000000000000..f87189ef13d5
--- /dev/null
+++ b/drivers/gpu/drm/xe/tests/xe_guc_klv_helpers_kunit.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0 AND MIT
+/*
+ * Copyright © 2026 Intel Corporation
+ */
+
+#include <kunit/test.h>
+#include <kunit/test-bug.h>
+
+#define TEST_KEY	(GUC_KLV_RESERVED_RANGE_START + 0x3de)
+#define TEST_PAD	0xdeadbeef
+
+static void test_count(struct kunit *test)
+{
+	u32 value = 0x12345678;
+	u16 key = TEST_KEY;
+	u32 klvs[] = {
+		PREP_GUC_KLV(key + 0, 0),
+		PREP_GUC_KLV(key + 1, 1), value,
+		PREP_GUC_KLV(key + 2, 2), value, value,
+		PREP_GUC_KLV(key + 3, 0),
+		0, /* padding */
+	};
+
+	KUNIT_EXPECT_EQ(test, 0, xe_guc_klv_count(klvs, 0));
+	KUNIT_EXPECT_EQ(test, 1, xe_guc_klv_count(klvs, 1));
+	KUNIT_EXPECT_GT(test, 0, xe_guc_klv_count(klvs, 2));
+	KUNIT_EXPECT_EQ(test, 2, xe_guc_klv_count(klvs, 3));
+	KUNIT_EXPECT_GT(test, 0, xe_guc_klv_count(klvs, 4));
+	KUNIT_EXPECT_GT(test, 0, xe_guc_klv_count(klvs, 5));
+	KUNIT_EXPECT_EQ(test, 3, xe_guc_klv_count(klvs, 6));
+	KUNIT_EXPECT_EQ(test, 4, xe_guc_klv_count(klvs, 7));
+
+	/* 0 is treated as reserved KLV { KEY=0, LEN=0 } */
+	KUNIT_EXPECT_EQ(test, 5, xe_guc_klv_count(klvs, 8));
+}
+
+static void test_encode_u32(struct kunit *test)
+{
+	u32 *fail = ERR_PTR(-ENOMEM);
+	u32 value = 0x12345678;
+	u16 key = TEST_KEY;
+	u32 klvs[16];
+
+	memset32(klvs, TEST_PAD, ARRAY_SIZE(klvs));
+
+	KUNIT_EXPECT_PTR_EQ(test, ERR_PTR(-ENOSPC), xe_guc_klv_encode_u32(klvs, 0, key, value));
+	KUNIT_EXPECT_PTR_EQ(test, ERR_PTR(-ENOSPC), xe_guc_klv_encode_u32(klvs, 1, key, value));
+
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, xe_guc_klv_encode_u32(klvs, 2, key, value));
+	KUNIT_EXPECT_EQ(test, klvs[0], PREP_GUC_KLV(key, 1));
+	KUNIT_EXPECT_EQ(test, klvs[1], value);
+	KUNIT_EXPECT_EQ(test, klvs[2], TEST_PAD);
+	KUNIT_EXPECT_PTR_EQ(test, &klvs[2], xe_guc_klv_encode_u32(klvs, 2, key, value));
+	KUNIT_EXPECT_PTR_EQ(test,
+			    xe_guc_klv_encode_u32(klvs, 2, key, value),
+			    xe_guc_klv_encode_u32(klvs, ARRAY_SIZE(klvs), key, value));
+
+	KUNIT_ASSERT_PTR_EQ(test, fail, xe_guc_klv_encode_u32(fail, ARRAY_SIZE(klvs), key, value));
+}
+
+static void test_encode_u64(struct kunit *test)
+{
+	u64 value = 0x123456789abcdef0;
+	u32 *fail = ERR_PTR(-ENOMEM);
+	u16 key = TEST_KEY;
+	u32 klvs[16];
+
+	memset32(klvs, TEST_PAD, ARRAY_SIZE(klvs));
+
+	KUNIT_EXPECT_PTR_EQ(test, ERR_PTR(-ENOSPC), xe_guc_klv_encode_u64(klvs, 0, key, value));
+	KUNIT_EXPECT_PTR_EQ(test, ERR_PTR(-ENOSPC), xe_guc_klv_encode_u64(klvs, 1, key, value));
+	KUNIT_EXPECT_PTR_EQ(test, ERR_PTR(-ENOSPC), xe_guc_klv_encode_u64(klvs, 2, key, value));
+
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, xe_guc_klv_encode_u64(klvs, 3, key, value));
+	KUNIT_EXPECT_EQ(test, klvs[0], PREP_GUC_KLV(key, 2));
+	KUNIT_EXPECT_EQ(test, klvs[1], lower_32_bits(value));
+	KUNIT_EXPECT_EQ(test, klvs[2], upper_32_bits(value));
+	KUNIT_EXPECT_EQ(test, klvs[3], TEST_PAD);
+	KUNIT_EXPECT_PTR_EQ(test, &klvs[3], xe_guc_klv_encode_u64(klvs, 3, key, value));
+	KUNIT_EXPECT_PTR_EQ(test,
+			    xe_guc_klv_encode_u64(klvs, 3, key, value),
+			    xe_guc_klv_encode_u64(klvs, ARRAY_SIZE(klvs), key, value));
+
+	KUNIT_ASSERT_PTR_EQ(test, fail, xe_guc_klv_encode_u64(fail, ARRAY_SIZE(klvs), key, value));
+}
+
+static struct kunit_case guc_klv_helpers_test_cases[] = {
+	KUNIT_CASE(test_count),
+	KUNIT_CASE(test_encode_u32),
+	KUNIT_CASE(test_encode_u64),
+	{}
+};
+
+static struct kunit_suite guc_klv_helpers_suite = {
+	.name = "guc_klv_helpers",
+	.test_cases = guc_klv_helpers_test_cases,
+};
+
+kunit_test_suite(guc_klv_helpers_suite);
diff --git a/drivers/gpu/drm/xe/xe_guc_klv_helpers.c b/drivers/gpu/drm/xe/xe_guc_klv_helpers.c
index 3f5c88e2c949..96f5cd2ab4f3 100644
--- a/drivers/gpu/drm/xe/xe_guc_klv_helpers.c
+++ b/drivers/gpu/drm/xe/xe_guc_klv_helpers.c
@@ -362,3 +362,7 @@ int xe_guc_klv_parser(const u32 *klvs, u32 num_dwords, void *obj,
 
 	return total;
 }
+
+#if IS_BUILTIN(CONFIG_DRM_XE_KUNIT_TEST)
+#include "tests/xe_guc_klv_helpers_kunit.c"
+#endif
-- 
2.47.1