[RFC PATCH v2 17/17] drm/vkms: Add kunit tests for linear and sRGB LUTs

[Harry Wentland <harry.wentland@amd.com>]

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Pekka Paalanen <pekka.paalanen@collabora.com>
Cc: Simon Ser <contact@emersion.fr>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Melissa Wen <mwen@igalia.com>
Cc: Jonas Ådahl <jadahl@redhat.com>
Cc: Sebastian Wick <sebastian.wick@redhat.com>
Cc: Shashank Sharma <shashank.sharma@amd.com>
Cc: Alexander Goins <agoins@nvidia.com>
Cc: Joshua Ashton <joshua@froggi.es>
Cc: Michel Dänzer <mdaenzer@redhat.com>
Cc: Aleix Pol <aleixpol@kde.org>
Cc: Xaver Hugl <xaver.hugl@gmail.com>
Cc: Victoria Brekenfeld <victoria@system76.com>
Cc: Sima <daniel@ffwll.ch>
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Naseer Ahmed <quic_naseer@quicinc.com>
Cc: Christopher Braga <quic_cbraga@quicinc.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Arthur Grillo <arthurgrillo@riseup.net>
Cc: Hector Martin <marcan@marcan.st>
Cc: Liviu Dudau <Liviu.Dudau@arm.com>
Cc: Sasha McIntosh <sashamcintosh@google.com>
---
 drivers/gpu/drm/vkms/tests/vkms_color_tests.c | 38 ++++++++++++++++++-
 drivers/gpu/drm/vkms/vkms_composer.c          | 13 +------
 drivers/gpu/drm/vkms/vkms_composer.h          | 14 +++++++
 3 files changed, 52 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/vkms/tests/vkms_color_tests.c b/drivers/gpu/drm/vkms/tests/vkms_color_tests.c
index 843b2e1d607e..14decb5d1b64 100644
--- a/drivers/gpu/drm/vkms/tests/vkms_color_tests.c
+++ b/drivers/gpu/drm/vkms/tests/vkms_color_tests.c
@@ -5,6 +5,7 @@
 #include <drm/drm_fixed.h>
 
 #include "../vkms_composer.h"
+#include "../vkms_luts.h"
 
 #define TEST_LUT_SIZE 16
 
@@ -33,7 +34,6 @@ const struct vkms_color_lut test_linear_lut = {
 	.channel_value2index_ratio = 0xf000fll
 };
 
-
 static void vkms_color_test_get_lut_index(struct kunit *test)
 {
 	int i;
@@ -42,6 +42,19 @@ static void vkms_color_test_get_lut_index(struct kunit *test)
 
 	for (i = 0; i < TEST_LUT_SIZE; i++)
 		KUNIT_EXPECT_EQ(test, drm_fixp2int_ceil(get_lut_index(&test_linear_lut, test_linear_array[i].red)), i);
+
+	KUNIT_EXPECT_EQ(test, drm_fixp2int(get_lut_index(&srgb_eotf, 0x0)), 0x0);
+	KUNIT_EXPECT_EQ(test, drm_fixp2int_ceil(get_lut_index(&srgb_eotf, 0x0)), 0x0);
+	KUNIT_EXPECT_EQ(test, drm_fixp2int_ceil(get_lut_index(&srgb_eotf, 0x101)), 0x1);
+	KUNIT_EXPECT_EQ(test, drm_fixp2int_ceil(get_lut_index(&srgb_eotf, 0x202)), 0x2);
+
+	KUNIT_EXPECT_EQ(test, drm_fixp2int(get_lut_index(&srgb_inv_eotf, 0x0)), 0x0);
+	KUNIT_EXPECT_EQ(test, drm_fixp2int_ceil(get_lut_index(&srgb_inv_eotf, 0x0)), 0x0);
+	KUNIT_EXPECT_EQ(test, drm_fixp2int_ceil(get_lut_index(&srgb_inv_eotf, 0x101)), 0x1);
+	KUNIT_EXPECT_EQ(test, drm_fixp2int_ceil(get_lut_index(&srgb_inv_eotf, 0x202)), 0x2);
+
+	KUNIT_EXPECT_EQ(test, drm_fixp2int_ceil(get_lut_index(&srgb_eotf, 0xfefe)), 0xfe);
+	KUNIT_EXPECT_EQ(test, drm_fixp2int_ceil(get_lut_index(&srgb_eotf, 0xffff)), 0xff);
 }
 
 static void vkms_color_test_lerp(struct kunit *test)
@@ -49,9 +62,32 @@ static void vkms_color_test_lerp(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, lerp_u16(0x0, 0x10, 0x80000000), 0x8);
 }
 
+static void vkms_color_test_linear(struct kunit *test)
+{
+	for (int i = 0; i < LUT_SIZE; i++) {
+		int linear = apply_lut_to_channel_value(&linear_eotf, i * 0x101, LUT_RED);
+		KUNIT_EXPECT_EQ(test, DIV_ROUND_CLOSEST(linear, 0x101), i);
+	}
+}
+
+static void vkms_color_srgb_inv_srgb(struct kunit *test)
+{
+	u16 srgb, final;
+
+	for (int i = 0; i < LUT_SIZE; i++) {
+		srgb = apply_lut_to_channel_value(&srgb_eotf, i * 0x101, LUT_RED);
+		final = apply_lut_to_channel_value(&srgb_inv_eotf, srgb, LUT_RED);
+
+		KUNIT_EXPECT_GE(test, final / 0x101, i-1);
+		KUNIT_EXPECT_LE(test, final / 0x101, i+1);
+	}
+}
+
 static struct kunit_case vkms_color_test_cases[] = {
 	KUNIT_CASE(vkms_color_test_get_lut_index),
 	KUNIT_CASE(vkms_color_test_lerp),
+	KUNIT_CASE(vkms_color_test_linear),
+	KUNIT_CASE(vkms_color_srgb_inv_srgb),
 	{}
 };
 
diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
index 73b7d5e94021..24c984f2876f 100644
--- a/drivers/gpu/drm/vkms/vkms_composer.c
+++ b/drivers/gpu/drm/vkms/vkms_composer.c
@@ -110,18 +110,7 @@ s64 get_lut_index(const struct vkms_color_lut *lut, u16 channel_value)
 	return drm_fixp_mul(color_channel_fp, lut->channel_value2index_ratio);
 }
 
-/*
- * This enum is related to the positions of the variables inside
- * `struct drm_color_lut`, so the order of both needs to be the same.
- */
-enum lut_channel {
-	LUT_RED = 0,
-	LUT_GREEN,
-	LUT_BLUE,
-	LUT_RESERVED
-};
-
-static u16 apply_lut_to_channel_value(const struct vkms_color_lut *lut, u16 channel_value,
+u16 apply_lut_to_channel_value(const struct vkms_color_lut *lut, u16 channel_value,
 				      enum lut_channel channel)
 {
 	s64 lut_index = get_lut_index(lut, channel_value);
diff --git a/drivers/gpu/drm/vkms/vkms_composer.h b/drivers/gpu/drm/vkms/vkms_composer.h
index 11c5de9cc961..d92497c555eb 100644
--- a/drivers/gpu/drm/vkms/vkms_composer.h
+++ b/drivers/gpu/drm/vkms/vkms_composer.h
@@ -8,4 +8,18 @@
 s64 get_lut_index(const struct vkms_color_lut *lut, u16 channel_value);
 u16 lerp_u16(u16 a, u16 b, s64 t);
 
+/*
+ * This enum is related to the positions of the variables inside
+ * `struct drm_color_lut`, so the order of both needs to be the same.
+ */
+enum lut_channel {
+	LUT_RED = 0,
+	LUT_GREEN,
+	LUT_BLUE,
+	LUT_RESERVED
+};
+
+u16 apply_lut_to_channel_value(const struct vkms_color_lut *lut, u16 channel_value,
+			       enum lut_channel channel);
+
 #endif /* _VKMS_COMPOSER_H_ */
\ No newline at end of file
-- 
2.42.0