[PATCH libdrm v2 03/10] util: Fix 16 bpp patterns on big-endian

[Geert Uytterhoeven]

DRM formats are defined to be little-endian, unless the
DRM_FORMAT_BIG_ENDIAN flag is set.  Hence writes of multi-byte pixel
values need to take endianness into account.

Introduce a swap16() helper to byteswap 16-bit values, and a
cpu_to_le16() helper to convert 16-bit values from CPU-endian to
little-endian, and use the latter in the various pattern fill functions
for 16-bit formats.

Signed-off-by: Geert Uytterhoeven <ge...@linux-m68k.org>
---
Works now with both Linux' drm_fb_swab() and my own
drm_fb_rgb565_to_rgb332_line() (the latter uses le16_to_cpu() to read
pixel values from memory).

v2:
  - New.
---
 tests/util/pattern.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/tests/util/pattern.c b/tests/util/pattern.c
index 26e0614bd4faa620..c0bd382fbced90fb 100644
--- a/tests/util/pattern.c
+++ b/tests/util/pattern.c
@@ -61,6 +61,11 @@ struct color_yuv {
          .u = MAKE_YUV_601_U(r, g, b), \
          .v = MAKE_YUV_601_V(r, g, b) }
 
+static inline uint16_t swap16(uint16_t x)
+{
+       return ((x & 0x00ffU) << 8) | ((x & 0xff00U) >> 8);
+}
+
 static inline uint32_t swap32(uint32_t x)
 {
        return ((x & 0x000000ffU) << 24) |
@@ -70,8 +75,10 @@ static inline uint32_t swap32(uint32_t x)
 }
 
 #if defined(__BIG_ENDIAN__) || defined(__ARM_BIG_ENDIAN) || 
defined(__mc68000__) || defined(__MIPSEB__) || defined(__s390__) || 
defined(__sparc__)
+#define cpu_to_le16(x) swap16(x)
 #define cpu_to_le32(x) swap32(x)
 #else
+#define cpu_to_le16(x) (x)
 #define cpu_to_le32(x) (x)
 #endif
 
@@ -410,26 +417,26 @@ static void fill_smpte_rgb16(const struct util_rgb_info 
*rgb, void *mem,
 
        for (y = 0; y < height * 6 / 9; ++y) {
                for (x = 0; x < width; ++x)
-                       ((uint16_t *)mem)[x] = colors_top[x * 7 / width];
+                       ((uint16_t *)mem)[x] = cpu_to_le16(colors_top[x * 7 / 
width]);
                mem += stride;
        }
 
        for (; y < height * 7 / 9; ++y) {
                for (x = 0; x < width; ++x)
-                       ((uint16_t *)mem)[x] = colors_middle[x * 7 / width];
+                       ((uint16_t *)mem)[x] = cpu_to_le16(colors_middle[x * 7 
/ width]);
                mem += stride;
        }
 
        for (; y < height; ++y) {
                for (x = 0; x < width * 5 / 7; ++x)
                        ((uint16_t *)mem)[x] =
-                               colors_bottom[x * 4 / (width * 5 / 7)];
+                               cpu_to_le16(colors_bottom[x * 4 / (width * 5 / 
7)]);
                for (; x < width * 6 / 7; ++x)
                        ((uint16_t *)mem)[x] =
-                               colors_bottom[(x - width * 5 / 7) * 3
-                                             / (width / 7) + 4];
+                               cpu_to_le16(colors_bottom[(x - width * 5 / 7) * 
3
+                                                         / (width / 7) + 4]);
                for (; x < width; ++x)
-                       ((uint16_t *)mem)[x] = colors_bottom[7];
+                       ((uint16_t *)mem)[x] = cpu_to_le16(colors_bottom[7]);
                mem += stride;
        }
 }
@@ -1272,7 +1279,7 @@ static void fill_tiles_rgb16(const struct 
util_format_info *info, void *mem,
                                          (rgb32 >> 8) & 0xff, rgb32 & 0xff,
                                          255);
 
-                       ((uint16_t *)mem)[x] = color;
+                       ((uint16_t *)mem)[x] = cpu_to_le16(color);
                }
                mem += stride;
        }
-- 
2.25.1