drm/vkms: Add kunit tests for VKMS LUT handling

Debugging LUT math is much easier when we can unit test
it. Add kunit functionality to VKMS and add tests for
 - get_lut_index
 - lerp_u16

Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Cc: Arthur Grillo <arthurgrillo@riseup.net>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Simon Ser <contact@emersion.fr>
Link: https://patch.msgid.link/20251115000237.3561250-3-alex.hung@amd.com

diff --git a/drivers/gpu/drm/vkms/tests/Makefile b/drivers/gpu/drm/vkms/tests/Makefile
index 5750f0bd9d4018c292903e573c780f58eb2940a3..d4d9ba8d4c54197c771f31f59aa3a4035a911547 100644 (file)
--- a/drivers/gpu/drm/vkms/tests/Makefile
+++ b/drivers/gpu/drm/vkms/tests/Makefile
@@ -2,6 +2,7 @@
 
 vkms-kunit-tests-y := \
        vkms_config_test.o \
-       vkms_format_test.o
+       vkms_format_test.o \
+       vkms_color_test.o
 
 obj-$(CONFIG_DRM_VKMS_KUNIT_TEST) += vkms-kunit-tests.o

diff --git a/drivers/gpu/drm/vkms/tests/vkms_color_test.c b/drivers/gpu/drm/vkms/tests/vkms_color_test.c
new file mode 100644 (file)
index 0000000..bd6e9d0
--- /dev/null
+++ b/drivers/gpu/drm/vkms/tests/vkms_color_test.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <kunit/test.h>
+
+#include <drm/drm_fixed.h>
+#include <drm/drm_mode.h>
+#include "../vkms_composer.h"
+#include "../vkms_drv.h"
+
+#define TEST_LUT_SIZE 16
+
+MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
+
+static struct drm_color_lut test_linear_array[TEST_LUT_SIZE] = {
+       { 0x0, 0x0, 0x0, 0 },
+       { 0x1111, 0x1111, 0x1111, 0 },
+       { 0x2222, 0x2222, 0x2222, 0 },
+       { 0x3333, 0x3333, 0x3333, 0 },
+       { 0x4444, 0x4444, 0x4444, 0 },
+       { 0x5555, 0x5555, 0x5555, 0 },
+       { 0x6666, 0x6666, 0x6666, 0 },
+       { 0x7777, 0x7777, 0x7777, 0 },
+       { 0x8888, 0x8888, 0x8888, 0 },
+       { 0x9999, 0x9999, 0x9999, 0 },
+       { 0xaaaa, 0xaaaa, 0xaaaa, 0 },
+       { 0xbbbb, 0xbbbb, 0xbbbb, 0 },
+       { 0xcccc, 0xcccc, 0xcccc, 0 },
+       { 0xdddd, 0xdddd, 0xdddd, 0 },
+       { 0xeeee, 0xeeee, 0xeeee, 0 },
+       { 0xffff, 0xffff, 0xffff, 0 },
+};
+
+/* lerp test parameters */
+struct vkms_color_test_lerp_params {
+       s64 t;
+       __u16 a;
+       __u16 b;
+       __u16 expected;
+};
+
+/* lerp test cases */
+static const struct vkms_color_test_lerp_params color_test_lerp_cases[] = {
+       /* Half-way round down */
+       { 0x80000000 - 1, 0x0, 0x10, 0x8 },
+       { 0x80000000 - 1, 0x1, 0x10, 0x8 },     /* Odd a */
+       { 0x80000000 - 1, 0x1, 0xf, 0x8 },      /* Odd b */
+       { 0x80000000 - 1, 0x10, 0x10, 0x10 },   /* b = a */
+       { 0x80000000 - 1, 0x10, 0x11, 0x10 },   /* b = a + 1*/
+       /* Half-way round up */
+       { 0x80000000, 0x0, 0x10, 0x8 },
+       { 0x80000000, 0x1, 0x10, 0x9 },         /* Odd a */
+       { 0x80000000, 0x1, 0xf, 0x8 },          /* Odd b */
+       { 0x80000000, 0x10, 0x10, 0x10 },       /* b = a */
+       { 0x80000000, 0x10, 0x11, 0x11 },       /* b = a + 1*/
+       /*  t = 0.0 */
+       { 0x0, 0x0, 0x10, 0x0 },
+       { 0x0, 0x1, 0x10, 0x1 },                /* Odd a */
+       { 0x0, 0x1, 0xf, 0x1 },                 /* Odd b */
+       { 0x0, 0x10, 0x10, 0x10 },              /* b = a */
+       { 0x0, 0x10, 0x11, 0x10 },              /* b = a + 1*/
+       /*  t = 1.0 */
+       { 0x100000000, 0x0, 0x10, 0x10 },
+       { 0x100000000, 0x1, 0x10, 0x10 },       /* Odd a */
+       { 0x100000000, 0x1, 0xf, 0xf },         /* Odd b */
+       { 0x100000000, 0x10, 0x10, 0x10 },      /* b = a */
+       { 0x100000000, 0x10, 0x11, 0x11 },      /* b = a + 1*/
+       /*  t = 0.0 + 1 */
+       { 0x0 + 1, 0x0, 0x10, 0x0 },
+       { 0x0 + 1, 0x1, 0x10, 0x1 },            /* Odd a */
+       { 0x0 + 1, 0x1, 0xf, 0x1 },             /* Odd b */
+       { 0x0 + 1, 0x10, 0x10, 0x10 },          /* b = a */
+       { 0x0 + 1, 0x10, 0x11, 0x10 },          /* b = a + 1*/
+       /*  t = 1.0 - 1 */
+       { 0x100000000 - 1, 0x0, 0x10, 0x10 },
+       { 0x100000000 - 1, 0x1, 0x10, 0x10 },   /* Odd a */
+       { 0x100000000 - 1, 0x1, 0xf, 0xf },     /* Odd b */
+       { 0x100000000 - 1, 0x10, 0x10, 0x10 },  /* b = a */
+       { 0x100000000 - 1, 0x10, 0x11, 0x11 },  /* b = a + 1*/
+       /*  t chosen to verify the flipping point of result a (or b) to a+1 (or b-1) */
+       { 0x80000000 - 1, 0x0, 0x1, 0x0 },
+       { 0x80000000, 0x0, 0x1, 0x1 },
+};
+
+static const struct vkms_color_lut test_linear_lut = {
+       .base = test_linear_array,
+       .lut_length = TEST_LUT_SIZE,
+       .channel_value2index_ratio = 0xf000fll
+};
+
+static void vkms_color_test_get_lut_index(struct kunit *test)
+{
+       s64 lut_index;
+       int i;
+
+       lut_index = get_lut_index(&test_linear_lut, test_linear_array[0].red);
+       KUNIT_EXPECT_EQ(test, drm_fixp2int(lut_index), 0);
+
+       for (i = 0; i < TEST_LUT_SIZE; i++) {
+               lut_index = get_lut_index(&test_linear_lut, test_linear_array[i].red);
+               KUNIT_EXPECT_EQ(test, drm_fixp2int_ceil(lut_index), i);
+       }
+}
+
+static void vkms_color_test_lerp(struct kunit *test)
+{
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(color_test_lerp_cases); i++) {
+               const struct vkms_color_test_lerp_params *params = &color_test_lerp_cases[i];
+
+               KUNIT_EXPECT_EQ(test, lerp_u16(params->a, params->b, params->t), params->expected);
+       }
+}
+
+static struct kunit_case vkms_color_test_cases[] = {
+       KUNIT_CASE(vkms_color_test_get_lut_index),
+       KUNIT_CASE(vkms_color_test_lerp),
+       {}
+};
+
+static struct kunit_suite vkms_color_test_suite = {
+       .name = "vkms-color",
+       .test_cases = vkms_color_test_cases,
+};
+
+kunit_test_suite(vkms_color_test_suite);
+
+MODULE_DESCRIPTION("Kunit test for VKMS LUT handling");
+MODULE_LICENSE("GPL");

diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
index c1ab12a44621020adfb6ee880f833a5c1ba970cb..5127e3be9e1ad467e07c5d7bfea633484cac8c11 100644 (file)
--- a/drivers/gpu/drm/vkms/vkms_composer.c
+++ b/drivers/gpu/drm/vkms/vkms_composer.c
@@ -11,8 +11,9 @@
 #include <drm/drm_print.h>
 #include <drm/drm_vblank.h>
 #include <linux/minmax.h>
+#include <kunit/visibility.h>
 
-#include "vkms_drv.h"
+#include "vkms_composer.h"
 
 static u16 pre_mul_blend_channel(u16 src, u16 dst, u16 alpha)
 {
@@ -61,7 +62,7 @@ static void fill_background(const struct pixel_argb_u16 *background_color,
 }
 
 // lerp(a, b, t) = a + (b - a) * t
-static u16 lerp_u16(u16 a, u16 b, s64 t)
+VISIBLE_IF_KUNIT u16 lerp_u16(u16 a, u16 b, s64 t)
 {
        s64 a_fp = drm_int2fixp(a);
        s64 b_fp = drm_int2fixp(b);
@@ -70,13 +71,15 @@ static u16 lerp_u16(u16 a, u16 b, s64 t)
 
        return drm_fixp2int_round(a_fp + delta);
 }
+EXPORT_SYMBOL_IF_KUNIT(lerp_u16);
 
-static s64 get_lut_index(const struct vkms_color_lut *lut, u16 channel_value)
+VISIBLE_IF_KUNIT s64 get_lut_index(const struct vkms_color_lut *lut, u16 channel_value)
 {
        s64 color_channel_fp = drm_int2fixp(channel_value);
 
        return drm_fixp_mul(color_channel_fp, lut->channel_value2index_ratio);
 }
+EXPORT_SYMBOL_IF_KUNIT(get_lut_index);
 
 /*
  * This enum is related to the positions of the variables inside

diff --git a/drivers/gpu/drm/vkms/vkms_composer.h b/drivers/gpu/drm/vkms/vkms_composer.h
new file mode 100644 (file)
index 0000000..45f5e6a
--- /dev/null
+++ b/drivers/gpu/drm/vkms/vkms_composer.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+
+#ifndef _VKMS_COMPOSER_H_
+#define _VKMS_COMPOSER_H_
+
+#include <kunit/visibility.h>
+#include "vkms_drv.h"
+
+#if IS_ENABLED(CONFIG_KUNIT)
+u16 lerp_u16(u16 a, u16 b, s64 t);
+s64 get_lut_index(const struct vkms_color_lut *lut, u16 channel_value);
+#endif
+
+#endif /* _VKMS_COMPOSER_H_ */