drm/vkms: Create KUnit tests for YUV conversions

Create KUnit tests to test the conversion between YUV and RGB. Test each
conversion and range combination with some common colors.

The code used to compute the expected result can be found in comment.

[Louis Chauvet:
- fix minor formating issues (whitespace, double line)
- change expected alpha from 0x0000 to 0xffff
- adapt to the new get_conversion_matrix usage
- apply the changes from Arthur
- move struct pixel_yuv_u8 to the test itself]

Signed-off-by: Arthur Grillo <arthurgrillo@riseup.net>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20250415-yuv-v18-6-f2918f71ec4b@bootlin.com
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>

diff --git a/drivers/gpu/drm/vkms/tests/Makefile b/drivers/gpu/drm/vkms/tests/Makefile
index 9ded37b67a464f2d1a8433245c1ba5cc07e5534f..0ee077942ae2696b7fd7843d74c3ee0f9e65bc3c 100644 (file)
--- a/drivers/gpu/drm/vkms/tests/Makefile
+++ b/drivers/gpu/drm/vkms/tests/Makefile
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
 obj-$(CONFIG_DRM_VKMS_KUNIT_TEST) += vkms_config_test.o
+obj-$(CONFIG_DRM_VKMS_KUNIT_TESTS) += vkms_format_test.o

diff --git a/drivers/gpu/drm/vkms/tests/vkms_format_test.c b/drivers/gpu/drm/vkms/tests/vkms_format_test.c
new file mode 100644 (file)
index 0000000..2e1daef
--- /dev/null
+++ b/drivers/gpu/drm/vkms/tests/vkms_format_test.c
@@ -0,0 +1,280 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <kunit/test.h>
+
+#include <drm/drm_fixed.h>
+#include <drm/drm_fourcc.h>
+
+#include "../../drm_crtc_internal.h"
+
+#include "../vkms_formats.h"
+
+#define TEST_BUFF_SIZE 50
+
+MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
+
+/**
+ * struct pixel_yuv_u8 - Internal representation of a pixel color.
+ * @y: Luma value, stored in 8 bits, without padding, using
+ *     machine endianness
+ * @u: Blue difference chroma value, stored in 8 bits, without padding, using
+ *     machine endianness
+ * @v: Red difference chroma value, stored in 8 bits, without padding, using
+ *     machine endianness
+ */
+struct pixel_yuv_u8 {
+       u8 y, u, v;
+};
+
+/*
+ * struct yuv_u8_to_argb_u16_case - Reference values to test the color
+ * conversions in VKMS between YUV to ARGB
+ *
+ * @encoding: Encoding used to convert RGB to YUV
+ * @range: Range used to convert RGB to YUV
+ * @n_colors: Count of test colors in this case
+ * @format_pair.name: Name used for this color conversion, used to
+ *                    clarify the test results
+ * @format_pair.rgb: RGB color tested
+ * @format_pair.yuv: Same color as @format_pair.rgb, but converted to
+ *                   YUV using @encoding and @range.
+ */
+struct yuv_u8_to_argb_u16_case {
+       enum drm_color_encoding encoding;
+       enum drm_color_range range;
+       size_t n_colors;
+       struct format_pair {
+               char *name;
+               struct pixel_yuv_u8 yuv;
+               struct pixel_argb_u16 argb;
+       } colors[TEST_BUFF_SIZE];
+};
+
+/*
+ * The YUV color representation were acquired via the colour python framework.
+ * Below are the function calls used for generating each case.
+ *
+ * For more information got to the docs:
+ * https://colour.readthedocs.io/en/master/generated/colour.RGB_to_YCbCr.html
+ */
+static struct yuv_u8_to_argb_u16_case yuv_u8_to_argb_u16_cases[] = {
+       /*
+        * colour.RGB_to_YCbCr(<rgb color in 16 bit form>,
+        *                     K=colour.WEIGHTS_YCBCR["ITU-R BT.601"],
+        *                     in_bits = 16,
+        *                     in_legal = False,
+        *                     in_int = True,
+        *                     out_bits = 8,
+        *                     out_legal = False,
+        *                     out_int = True)
+        *
+        * Tests cases for color conversion generated by converting RGB
+        * values to YUV BT601 full range using the ITU-R BT.601 weights.
+        */
+       {
+               .encoding = DRM_COLOR_YCBCR_BT601,
+               .range = DRM_COLOR_YCBCR_FULL_RANGE,
+               .n_colors = 6,
+               .colors = {
+                       { "white", { 0xff, 0x80, 0x80 }, { 0xffff, 0xffff, 0xffff, 0xffff }},
+                       { "gray",  { 0x80, 0x80, 0x80 }, { 0xffff, 0x8080, 0x8080, 0x8080 }},
+                       { "black", { 0x00, 0x80, 0x80 }, { 0xffff, 0x0000, 0x0000, 0x0000 }},
+                       { "red",   { 0x4c, 0x55, 0xff }, { 0xffff, 0xffff, 0x0000, 0x0000 }},
+                       { "green", { 0x96, 0x2c, 0x15 }, { 0xffff, 0x0000, 0xffff, 0x0000 }},
+                       { "blue",  { 0x1d, 0xff, 0x6b }, { 0xffff, 0x0000, 0x0000, 0xffff }},
+               },
+       },
+       /*
+        * colour.RGB_to_YCbCr(<rgb color in 16 bit form>,
+        *                     K=colour.WEIGHTS_YCBCR["ITU-R BT.601"],
+        *                     in_bits = 16,
+        *                     in_legal = False,
+        *                     in_int = True,
+        *                     out_bits = 8,
+        *                     out_legal = True,
+        *                     out_int = True)
+        * Tests cases for color conversion generated by converting RGB
+        * values to YUV BT601 limited range using the ITU-R BT.601 weights.
+        */
+       {
+               .encoding = DRM_COLOR_YCBCR_BT601,
+               .range = DRM_COLOR_YCBCR_LIMITED_RANGE,
+               .n_colors = 6,
+               .colors = {
+                       { "white", { 0xeb, 0x80, 0x80 }, { 0xffff, 0xffff, 0xffff, 0xffff }},
+                       { "gray",  { 0x7e, 0x80, 0x80 }, { 0xffff, 0x8080, 0x8080, 0x8080 }},
+                       { "black", { 0x10, 0x80, 0x80 }, { 0xffff, 0x0000, 0x0000, 0x0000 }},
+                       { "red",   { 0x51, 0x5a, 0xf0 }, { 0xffff, 0xffff, 0x0000, 0x0000 }},
+                       { "green", { 0x91, 0x36, 0x22 }, { 0xffff, 0x0000, 0xffff, 0x0000 }},
+                       { "blue",  { 0x29, 0xf0, 0x6e }, { 0xffff, 0x0000, 0x0000, 0xffff }},
+               },
+       },
+       /*
+        * colour.RGB_to_YCbCr(<rgb color in 16 bit form>,
+        *                     K=colour.WEIGHTS_YCBCR["ITU-R BT.709"],
+        *                     in_bits = 16,
+        *                     in_legal = False,
+        *                     in_int = True,
+        *                     out_bits = 8,
+        *                     out_legal = False,
+        *                     out_int = True)
+        * Tests cases for color conversion generated by converting RGB
+        * values to YUV BT709 full range using the ITU-R BT.709 weights.
+        */
+       {
+               .encoding = DRM_COLOR_YCBCR_BT709,
+               .range = DRM_COLOR_YCBCR_FULL_RANGE,
+               .n_colors = 6,
+               .colors = {
+                       { "white", { 0xff, 0x80, 0x80 }, { 0xffff, 0xffff, 0xffff, 0xffff }},
+                       { "gray",  { 0x80, 0x80, 0x80 }, { 0xffff, 0x8080, 0x8080, 0x8080 }},
+                       { "black", { 0x00, 0x80, 0x80 }, { 0xffff, 0x0000, 0x0000, 0x0000 }},
+                       { "red",   { 0x36, 0x63, 0xff }, { 0xffff, 0xffff, 0x0000, 0x0000 }},
+                       { "green", { 0xb6, 0x1e, 0x0c }, { 0xffff, 0x0000, 0xffff, 0x0000 }},
+                       { "blue",  { 0x12, 0xff, 0x74 }, { 0xffff, 0x0000, 0x0000, 0xffff }},
+               },
+       },
+       /*
+        * colour.RGB_to_YCbCr(<rgb color in 16 bit form>,
+        *                     K=colour.WEIGHTS_YCBCR["ITU-R BT.709"],
+        *                     in_bits = 16,
+        *                     int_legal = False,
+        *                     in_int = True,
+        *                     out_bits = 8,
+        *                     out_legal = True,
+        *                     out_int = True)
+        * Tests cases for color conversion generated by converting RGB
+        * values to YUV BT709 limited range using the ITU-R BT.709 weights.
+        */
+       {
+               .encoding = DRM_COLOR_YCBCR_BT709,
+               .range = DRM_COLOR_YCBCR_LIMITED_RANGE,
+               .n_colors = 6,
+               .colors = {
+                       { "white", { 0xeb, 0x80, 0x80 }, { 0xffff, 0xffff, 0xffff, 0xffff }},
+                       { "gray",  { 0x7e, 0x80, 0x80 }, { 0xffff, 0x8080, 0x8080, 0x8080 }},
+                       { "black", { 0x10, 0x80, 0x80 }, { 0xffff, 0x0000, 0x0000, 0x0000 }},
+                       { "red",   { 0x3f, 0x66, 0xf0 }, { 0xffff, 0xffff, 0x0000, 0x0000 }},
+                       { "green", { 0xad, 0x2a, 0x1a }, { 0xffff, 0x0000, 0xffff, 0x0000 }},
+                       { "blue",  { 0x20, 0xf0, 0x76 }, { 0xffff, 0x0000, 0x0000, 0xffff }},
+               },
+       },
+       /*
+        * colour.RGB_to_YCbCr(<rgb color in 16 bit form>,
+        *                     K=colour.WEIGHTS_YCBCR["ITU-R BT.2020"],
+        *                     in_bits = 16,
+        *                     in_legal = False,
+        *                     in_int = True,
+        *                     out_bits = 8,
+        *                     out_legal = False,
+        *                     out_int = True)
+        * Tests cases for color conversion generated by converting RGB
+        * values to YUV BT2020 full range using the ITU-R BT.2020 weights.
+        */
+       {
+               .encoding = DRM_COLOR_YCBCR_BT2020,
+               .range = DRM_COLOR_YCBCR_FULL_RANGE,
+               .n_colors = 6,
+               .colors = {
+                       { "white", { 0xff, 0x80, 0x80 }, { 0xffff, 0xffff, 0xffff, 0xffff }},
+                       { "gray",  { 0x80, 0x80, 0x80 }, { 0xffff, 0x8080, 0x8080, 0x8080 }},
+                       { "black", { 0x00, 0x80, 0x80 }, { 0xffff, 0x0000, 0x0000, 0x0000 }},
+                       { "red",   { 0x43, 0x5c, 0xff }, { 0xffff, 0xffff, 0x0000, 0x0000 }},
+                       { "green", { 0xad, 0x24, 0x0b }, { 0xffff, 0x0000, 0xffff, 0x0000 }},
+                       { "blue",  { 0x0f, 0xff, 0x76 }, { 0xffff, 0x0000, 0x0000, 0xffff }},
+               },
+       },
+       /*
+        * colour.RGB_to_YCbCr(<rgb color in 16 bit form>,
+        *                     K=colour.WEIGHTS_YCBCR["ITU-R BT.2020"],
+        *                     in_bits = 16,
+        *                     in_legal = False,
+        *                     in_int = True,
+        *                     out_bits = 8,
+        *                     out_legal = True,
+        *                     out_int = True)
+        * Tests cases for color conversion generated by converting RGB
+        * values to YUV BT2020 limited range using the ITU-R BT.2020 weights.
+        */
+       {
+               .encoding = DRM_COLOR_YCBCR_BT2020,
+               .range = DRM_COLOR_YCBCR_LIMITED_RANGE,
+               .n_colors = 6,
+               .colors = {
+                       { "white", { 0xeb, 0x80, 0x80 }, { 0xffff, 0xffff, 0xffff, 0xffff }},
+                       { "gray",  { 0x7e, 0x80, 0x80 }, { 0xffff, 0x8080, 0x8080, 0x8080 }},
+                       { "black", { 0x10, 0x80, 0x80 }, { 0xffff, 0x0000, 0x0000, 0x0000 }},
+                       { "red",   { 0x4a, 0x61, 0xf0 }, { 0xffff, 0xffff, 0x0000, 0x0000 }},
+                       { "green", { 0xa4, 0x2f, 0x19 }, { 0xffff, 0x0000, 0xffff, 0x0000 }},
+                       { "blue",  { 0x1d, 0xf0, 0x77 }, { 0xffff, 0x0000, 0x0000, 0xffff }},
+               },
+       },
+};
+
+/*
+ * vkms_format_test_yuv_u8_to_argb_u16 - Testing the conversion between YUV
+ * colors to ARGB colors in VKMS
+ *
+ * This test will use the functions get_conversion_matrix_to_argb_u16 and
+ * argb_u16_from_yuv888 to convert YUV colors (stored in
+ * yuv_u8_to_argb_u16_cases) into ARGB colors.
+ *
+ * The conversion between YUV and RGB is not totally reversible, so there may be
+ * some difference between the expected value and the result.
+ * In addition, there may be some rounding error as the input color is 8 bits
+ * and output color is 16 bits.
+ */
+static void vkms_format_test_yuv_u8_to_argb_u16(struct kunit *test)
+{
+       const struct yuv_u8_to_argb_u16_case *param = test->param_value;
+       struct pixel_argb_u16 argb;
+
+       for (size_t i = 0; i < param->n_colors; i++) {
+               const struct format_pair *color = &param->colors[i];
+               struct conversion_matrix matrix;
+
+               get_conversion_matrix_to_argb_u16
+                       (DRM_FORMAT_NV12, param->encoding, param->range, &matrix);
+
+               argb = argb_u16_from_yuv888(color->yuv.y, color->yuv.u, color->yuv.v, &matrix);
+
+               KUNIT_EXPECT_LE_MSG(test, abs_diff(argb.a, color->argb.a), 0x1ff,
+                                   "On the A channel of the color %s expected 0x%04x, got 0x%04x",
+                                   color->name, color->argb.a, argb.a);
+               KUNIT_EXPECT_LE_MSG(test, abs_diff(argb.r, color->argb.r), 0x1ff,
+                                   "On the R channel of the color %s expected 0x%04x, got 0x%04x",
+                                   color->name, color->argb.r, argb.r);
+               KUNIT_EXPECT_LE_MSG(test, abs_diff(argb.g, color->argb.g), 0x1ff,
+                                   "On the G channel of the color %s expected 0x%04x, got 0x%04x",
+                                   color->name, color->argb.g, argb.g);
+               KUNIT_EXPECT_LE_MSG(test, abs_diff(argb.b, color->argb.b), 0x1ff,
+                                   "On the B channel of the color %s expected 0x%04x, got 0x%04x",
+                                   color->name, color->argb.b, argb.b);
+       }
+}
+
+static void vkms_format_test_yuv_u8_to_argb_u16_case_desc(struct yuv_u8_to_argb_u16_case *t,
+                                                         char *desc)
+{
+       snprintf(desc, KUNIT_PARAM_DESC_SIZE, "%s - %s",
+                drm_get_color_encoding_name(t->encoding), drm_get_color_range_name(t->range));
+}
+
+KUNIT_ARRAY_PARAM(yuv_u8_to_argb_u16, yuv_u8_to_argb_u16_cases,
+                 vkms_format_test_yuv_u8_to_argb_u16_case_desc
+);
+
+static struct kunit_case vkms_format_test_cases[] = {
+       KUNIT_CASE_PARAM(vkms_format_test_yuv_u8_to_argb_u16, yuv_u8_to_argb_u16_gen_params),
+       {}
+};
+
+static struct kunit_suite vkms_format_test_suite = {
+       .name = "vkms-format",
+       .test_cases = vkms_format_test_cases,
+};
+
+kunit_test_suite(vkms_format_test_suite);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Kunit test for vkms format conversion");

diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
index 8f7a5d54a076913879f03aa289ef9129acf2f7fa..9972780f3fa975ad8f5bcb71fa5c616071a8cf08 100644 (file)
--- a/drivers/gpu/drm/vkms/vkms_formats.c
+++ b/drivers/gpu/drm/vkms/vkms_formats.c
@@ -7,6 +7,8 @@
 #include <drm/drm_rect.h>
 #include <drm/drm_fixed.h>
 
+#include <kunit/visibility.h>
+
 #include "vkms_formats.h"
 
 /**
@@ -247,8 +249,8 @@ static struct pixel_argb_u16 argb_u16_from_RGB565(const __le16 *pixel)
        return out_pixel;
 }
 
-static struct pixel_argb_u16 argb_u16_from_yuv888(u8 y, u8 channel_1, u8 channel_2,
-                                                 const struct conversion_matrix *matrix)
+VISIBLE_IF_KUNIT struct pixel_argb_u16 argb_u16_from_yuv888(u8 y, u8 channel_1, u8 channel_2,
+                                                           const struct conversion_matrix *matrix)
 {
        u16 r, g, b;
        s64 fp_y, fp_channel_1, fp_channel_2;
@@ -278,6 +280,7 @@ static struct pixel_argb_u16 argb_u16_from_yuv888(u8 y, u8 channel_1, u8 channel
 
        return argb_u16_from_u16161616(0xffff, r, g, b);
 }
+EXPORT_SYMBOL_IF_KUNIT(argb_u16_from_yuv888);
 
 /*
  * The following functions are read_line function for each pixel format supported by VKMS.

diff --git a/drivers/gpu/drm/vkms/vkms_formats.h b/drivers/gpu/drm/vkms/vkms_formats.h
index d583855cb32027d16b73d2a5b5a0644b13191d08..b4fe62ab9c65d465925d29911f26612193a80799 100644 (file)
--- a/drivers/gpu/drm/vkms/vkms_formats.h
+++ b/drivers/gpu/drm/vkms/vkms_formats.h
@@ -13,4 +13,9 @@ void get_conversion_matrix_to_argb_u16(u32 format, enum drm_color_encoding encod
                                       enum drm_color_range range,
                                       struct conversion_matrix *matrix);
 
+#if IS_ENABLED(CONFIG_KUNIT)
+struct pixel_argb_u16 argb_u16_from_yuv888(u8 y, u8 channel_1, u8 channel_2,
+                                          const struct conversion_matrix *matrix);
+#endif
+
 #endif /* _VKMS_FORMATS_H_ */