drm/format-helper: Add KUnit tests for drm_fb_xrgb8888_to_gray8()

Extend the existing test cases to test the conversion from XRGB8888 to
grayscale.
Tested-by: Maíra Canal <mairacanal@riseup.net>
Reviewed-by: David Gow <davidgow@google.com>
Acked-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220926080837.65734-4-jose.exposito89@gmail.com

drivers/gpu/drm/tests/drm_format_helper_test.c

@@ -16,6 +16,11 @@
 
 #define TEST_BUF_SIZE 50
 
+struct convert_to_gray8_result {
+	unsigned int dst_pitch;
+	const u8 expected[TEST_BUF_SIZE];
+};
+
 struct convert_to_rgb332_result {
 	unsigned int dst_pitch;
 	const u8 expected[TEST_BUF_SIZE];
@@ -42,6 +47,7 @@ struct convert_xrgb8888_case {
 	unsigned int pitch;
 	struct drm_rect clip;
 	const u32 xrgb8888[TEST_BUF_SIZE];
+	struct convert_to_gray8_result gray8_result;
 	struct convert_to_rgb332_result rgb332_result;
 	struct convert_to_rgb565_result rgb565_result;
 	struct convert_to_rgb888_result rgb888_result;
@@ -54,6 +60,10 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
 		.pitch = 1 * 4,
 		.clip = DRM_RECT_INIT(0, 0, 1, 1),
 		.xrgb8888 = { 0x01FF0000 },
+		.gray8_result = {
+			.dst_pitch = 0,
+			.expected = { 0x4C },
+		},
 		.rgb332_result = {
 			.dst_pitch = 0,
 			.expected = { 0xE0 },
@@ -80,6 +90,10 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
 			0x00000000, 0x00000000,
 			0x00000000, 0x10FF0000,
 		},
+		.gray8_result = {
+			.dst_pitch = 0,
+			.expected = { 0x4C },
+		},
 		.rgb332_result = {
 			.dst_pitch = 0,
 			.expected = { 0xE0 },
@@ -113,6 +127,15 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
 			0x00000000, 0x550000FF, 0x66FF00FF, 0x00000000,
 			0x00000000, 0x77FFFF00, 0x8800FFFF, 0x00000000,
 		},
+		.gray8_result = {
+			.dst_pitch = 0,
+			.expected = {
+				0xFF, 0x00,
+				0x4C, 0x99,
+				0x19, 0x66,
+				0xE5, 0xB2,
+			},
+		},
 		.rgb332_result = {
 			.dst_pitch = 0,
 			.expected = {
@@ -166,6 +189,14 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
 			0xD16C7073, 0xA20E449C, 0xB2114D05,
 			0xC2A80303, 0xD26C7073, 0xA30E449C,
 		},
+		.gray8_result = {
+			.dst_pitch = 5,
+			.expected = {
+				0x3C, 0x33, 0x34, 0x00, 0x00,
+				0x6F, 0x3C, 0x33, 0x00, 0x00,
+				0x34, 0x6F, 0x3C, 0x00, 0x00,
+			},
+		},
 		.rgb332_result = {
 			.dst_pitch = 5,
 			.expected = {
@@ -257,6 +288,36 @@ static void convert_xrgb8888_case_desc(struct convert_xrgb8888_case *t,
 KUNIT_ARRAY_PARAM(convert_xrgb8888, convert_xrgb8888_cases,
 		  convert_xrgb8888_case_desc);
 
+static void drm_test_fb_xrgb8888_to_gray8(struct kunit *test)
+{
+	const struct convert_xrgb8888_case *params = test->param_value;
+	const struct convert_to_gray8_result *result = &params->gray8_result;
+	size_t dst_size;
+	__u8 *buf = NULL;
+	__u32 *xrgb8888 = NULL;
+	struct iosys_map dst, src;
+
+	struct drm_framebuffer fb = {
+		.format = drm_format_info(DRM_FORMAT_XRGB8888),
+		.pitches = { params->pitch, 0, 0 },
+	};
+
+	dst_size = conversion_buf_size(DRM_FORMAT_R8, result->dst_pitch,
+				       &params->clip);
+	KUNIT_ASSERT_GT(test, dst_size, 0);
+
+	buf = kunit_kzalloc(test, dst_size, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buf);
+	iosys_map_set_vaddr(&dst, buf);
+
+	xrgb8888 = le32buf_to_cpu(test, params->xrgb8888, TEST_BUF_SIZE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, xrgb8888);
+	iosys_map_set_vaddr(&src, xrgb8888);
+
+	drm_fb_xrgb8888_to_gray8(&dst, &result->dst_pitch, &src, &fb, &params->clip);
+	KUNIT_EXPECT_EQ(test, memcmp(buf, result->expected, dst_size), 0);
+}
+
 static void drm_test_fb_xrgb8888_to_rgb332(struct kunit *test)
 {
 	const struct convert_xrgb8888_case *params = test->param_value;
@@ -382,6 +443,7 @@ static void drm_test_fb_xrgb8888_to_xrgb2101010(struct kunit *test)
 }
 
 static struct kunit_case drm_format_helper_test_cases[] = {
+	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_gray8, convert_xrgb8888_gen_params),
 	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_rgb332, convert_xrgb8888_gen_params),
 	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_rgb565, convert_xrgb8888_gen_params),
 	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_rgb888, convert_xrgb8888_gen_params),