drm/format-helper: Add KUnit tests for drm_fb_xrgb8888_to_rgb565()

Extend the existing test cases to test the conversion from XRGB8888 to
RGB565.

The documentation and the color picker available on [1] are useful
resources to understand this patch and validate the values returned by
the conversion function.

Tested-by: Tales L. Aparecida <tales.aparecida@gmail.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Link: http://www.barth-dev.de/online/rgb565-color-picker/
Link: https://patchwork.freedesktop.org/patch/msgid/20220726230916.390575-5-jose.exposito89@gmail.com

diff --git a/drivers/gpu/drm/tests/drm_format_helper_test.c b/drivers/gpu/drm/tests/drm_format_helper_test.c
index bbe9e9f..26ecf3b 100644 (file)
--- a/drivers/gpu/drm/tests/drm_format_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_format_helper_test.c
@@ -21,12 +21,19 @@ struct convert_to_rgb332_result {
        const u8 expected[TEST_BUF_SIZE];
 };
 
+struct convert_to_rgb565_result {
+       unsigned int dst_pitch;
+       const u16 expected[TEST_BUF_SIZE];
+       const u16 expected_swab[TEST_BUF_SIZE];
+};
+
 struct convert_xrgb8888_case {
        const char *name;
        unsigned int pitch;
        struct drm_rect clip;
        const u32 xrgb8888[TEST_BUF_SIZE];
        struct convert_to_rgb332_result rgb332_result;
+       struct convert_to_rgb565_result rgb565_result;
 };
 
 static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
@@ -39,6 +46,11 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
                        .dst_pitch = 0,
                        .expected = { 0xE0 },
                },
+               .rgb565_result = {
+                       .dst_pitch = 0,
+                       .expected = { 0xF800 },
+                       .expected_swab = { 0x00F8 },
+               },
        },
        {
                .name = "single_pixel_clip_rectangle",
@@ -52,6 +64,11 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
                        .dst_pitch = 0,
                        .expected = { 0xE0 },
                },
+               .rgb565_result = {
+                       .dst_pitch = 0,
+                       .expected = { 0xF800 },
+                       .expected_swab = { 0x00F8 },
+               },
        },
        {
                /* Well known colors: White, black, red, green, blue, magenta,
@@ -77,6 +94,21 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
                                0xFC, 0x1F,
                        },
                },
+               .rgb565_result = {
+                       .dst_pitch = 0,
+                       .expected = {
+                               0xFFFF, 0x0000,
+                               0xF800, 0x07E0,
+                               0x001F, 0xF81F,
+                               0xFFE0, 0x07FF,
+                       },
+                       .expected_swab = {
+                               0xFFFF, 0x0000,
+                               0x00F8, 0xE007,
+                               0x1F00, 0x1FF8,
+                               0xE0FF, 0xFF07,
+                       },
+               },
        },
        {
                /* Randomly picked colors. Full buffer within the clip area. */
@@ -96,6 +128,19 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
                                0xA0, 0x6D, 0x0A, 0x00, 0x00,
                        },
                },
+               .rgb565_result = {
+                       .dst_pitch = 10,
+                       .expected = {
+                               0x0A33, 0x1260, 0xA800, 0x0000, 0x0000,
+                               0x6B8E, 0x0A33, 0x1260, 0x0000, 0x0000,
+                               0xA800, 0x6B8E, 0x0A33, 0x0000, 0x0000,
+                       },
+                       .expected_swab = {
+                               0x330A, 0x6012, 0x00A8, 0x0000, 0x0000,
+                               0x8E6B, 0x330A, 0x6012, 0x0000, 0x0000,
+                               0x00A8, 0x8E6B, 0x330A, 0x0000, 0x0000,
+                       },
+               },
        },
 };
 
@@ -175,8 +220,41 @@ static void xrgb8888_to_rgb332_test(struct kunit *test)
        KUNIT_EXPECT_EQ(test, memcmp(dst, result->expected, dst_size), 0);
 }
 
+static void xrgb8888_to_rgb565_test(struct kunit *test)
+{
+       const struct convert_xrgb8888_case *params = test->param_value;
+       const struct convert_to_rgb565_result *result = &params->rgb565_result;
+       size_t dst_size;
+       __u16 *dst = NULL;
+       __u32 *src = NULL;
+
+       struct drm_framebuffer fb = {
+               .format = drm_format_info(DRM_FORMAT_XRGB8888),
+               .pitches = { params->pitch, 0, 0 },
+       };
+
+       dst_size = conversion_buf_size(DRM_FORMAT_RGB565, result->dst_pitch,
+                                      &params->clip);
+       KUNIT_ASSERT_GT(test, dst_size, 0);
+
+       dst = kunit_kzalloc(test, dst_size, GFP_KERNEL);
+       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dst);
+
+       src = le32buf_to_cpu(test, params->xrgb8888, TEST_BUF_SIZE);
+       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, src);
+
+       drm_fb_xrgb8888_to_rgb565(dst, result->dst_pitch, src, &fb,
+                                 &params->clip, false);
+       KUNIT_EXPECT_EQ(test, memcmp(dst, result->expected, dst_size), 0);
+
+       drm_fb_xrgb8888_to_rgb565(dst, result->dst_pitch, src, &fb,
+                                 &params->clip, true);
+       KUNIT_EXPECT_EQ(test, memcmp(dst, result->expected_swab, dst_size), 0);
+}
+
 static struct kunit_case drm_format_helper_test_cases[] = {
        KUNIT_CASE_PARAM(xrgb8888_to_rgb332_test, convert_xrgb8888_gen_params),
+       KUNIT_CASE_PARAM(xrgb8888_to_rgb565_test, convert_xrgb8888_gen_params),
        {}
 };