drm/format-helper: Store RGB565 in little-endian order

Fix to-RGB565 conversion helpers to store the result in little-
endian byte order. Update test cases as well.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: José Expósito <jose.exposito89@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230102112927.26565-5-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index b98bd7c..f3f3b38 100644 (file)
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -322,7 +322,7 @@ EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb332);
 
 static void drm_fb_xrgb8888_to_rgb565_line(void *dbuf, const void *sbuf, unsigned int pixels)
 {
-       u16 *dbuf16 = dbuf;
+       __le16 *dbuf16 = dbuf;
        const __le32 *sbuf32 = sbuf;
        unsigned int x;
        u16 val16;
@@ -333,14 +333,15 @@ static void drm_fb_xrgb8888_to_rgb565_line(void *dbuf, const void *sbuf, unsigne
                val16 = ((pix & 0x00F80000) >> 8) |
                        ((pix & 0x0000FC00) >> 5) |
                        ((pix & 0x000000F8) >> 3);
-               dbuf16[x] = val16;
+               dbuf16[x] = cpu_to_le16(val16);
        }
 }
 
+/* TODO: implement this helper as conversion to RGB565|BIG_ENDIAN */
 static void drm_fb_xrgb8888_to_rgb565_swab_line(void *dbuf, const void *sbuf,
                                                unsigned int pixels)
 {
-       u16 *dbuf16 = dbuf;
+       __le16 *dbuf16 = dbuf;
        const __le32 *sbuf32 = sbuf;
        unsigned int x;
        u16 val16;
@@ -351,7 +352,7 @@ static void drm_fb_xrgb8888_to_rgb565_swab_line(void *dbuf, const void *sbuf,
                val16 = ((pix & 0x00F80000) >> 8) |
                        ((pix & 0x0000FC00) >> 5) |
                        ((pix & 0x000000F8) >> 3);
-               dbuf16[x] = swab16(val16);
+               dbuf16[x] = cpu_to_le16(swab16(val16));
        }
 }
 

diff --git a/drivers/gpu/drm/tests/drm_format_helper_test.c b/drivers/gpu/drm/tests/drm_format_helper_test.c
index e7c49e6..04fe373 100644 (file)
--- a/drivers/gpu/drm/tests/drm_format_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_format_helper_test.c
@@ -264,6 +264,21 @@ static size_t conversion_buf_size(u32 dst_format, unsigned int dst_pitch,
        return dst_pitch * drm_rect_height(clip);
 }
 
+static u16 *le16buf_to_cpu(struct kunit *test, const __le16 *buf, size_t buf_size)
+{
+       u16 *dst = NULL;
+       int n;
+
+       dst = kunit_kzalloc(test, sizeof(*dst) * buf_size, GFP_KERNEL);
+       if (!dst)
+               return NULL;
+
+       for (n = 0; n < buf_size; n++)
+               dst[n] = le16_to_cpu(buf[n]);
+
+       return dst;
+}
+
 static u32 *le32buf_to_cpu(struct kunit *test, const u32 *buf, size_t buf_size)
 {
        u32 *dst = NULL;
@@ -368,7 +383,7 @@ static void drm_test_fb_xrgb8888_to_rgb565(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 *buf = NULL;
+       u16 *buf = NULL;
        __le32 *xrgb8888 = NULL;
        struct iosys_map dst, src;
 
@@ -390,9 +405,12 @@ static void drm_test_fb_xrgb8888_to_rgb565(struct kunit *test)
        iosys_map_set_vaddr(&src, xrgb8888);
 
        drm_fb_xrgb8888_to_rgb565(&dst, &result->dst_pitch, &src, &fb, &params->clip, false);
+       buf = le16buf_to_cpu(test, (__force const __le16 *)buf, dst_size / sizeof(__le16));
        KUNIT_EXPECT_EQ(test, memcmp(buf, result->expected, dst_size), 0);
 
+       buf = dst.vaddr; /* restore original value of buf */
        drm_fb_xrgb8888_to_rgb565(&dst, &result->dst_pitch, &src, &fb, &params->clip, true);
+       buf = le16buf_to_cpu(test, (__force const __le16 *)buf, dst_size / sizeof(__le16));
        KUNIT_EXPECT_EQ(test, memcmp(buf, result->expected_swab, dst_size), 0);
 }