drm/format-helper: Remove optional byte-swap from line convertion

Implement per-pixel byte swapping in a separate conversion helper
for the single function that requires it. Select the correct helper
for each conversion.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220427141409.22842-3-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index f704993..b7daa40 100644 (file)
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -229,8 +229,7 @@ void drm_fb_xrgb8888_to_rgb332(void *dst, unsigned int dst_pitch, const void *sr
 EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb332);
 
 static void drm_fb_xrgb8888_to_rgb565_line(u16 *dbuf, const u32 *sbuf,
-                                          unsigned int pixels,
-                                          bool swab)
+                                          unsigned int pixels)
 {
        unsigned int x;
        u16 val16;
@@ -239,10 +238,21 @@ static void drm_fb_xrgb8888_to_rgb565_line(u16 *dbuf, const u32 *sbuf,
                val16 = ((sbuf[x] & 0x00F80000) >> 8) |
                        ((sbuf[x] & 0x0000FC00) >> 5) |
                        ((sbuf[x] & 0x000000F8) >> 3);
-               if (swab)
-                       dbuf[x] = swab16(val16);
-               else
-                       dbuf[x] = val16;
+               dbuf[x] = val16;
+       }
+}
+
+static void drm_fb_xrgb8888_to_rgb565_swab_line(u16 *dbuf, const u32 *sbuf,
+                                               unsigned int pixels)
+{
+       unsigned int x;
+       u16 val16;
+
+       for (x = 0; x < pixels; x++) {
+               val16 = ((sbuf[x] & 0x00F80000) >> 8) |
+                       ((sbuf[x] & 0x0000FC00) >> 5) |
+                       ((sbuf[x] & 0x000000F8) >> 3);
+               dbuf[x] = swab16(val16);
        }
 }
 
@@ -282,7 +292,10 @@ void drm_fb_xrgb8888_to_rgb565(void *dst, unsigned int dst_pitch, const void *va
        vaddr += clip_offset(clip, fb->pitches[0], sizeof(u32));
        for (y = 0; y < lines; y++) {
                memcpy(sbuf, vaddr, src_len);
-               drm_fb_xrgb8888_to_rgb565_line(dst, sbuf, linepixels, swab);
+               if (swab)
+                       drm_fb_xrgb8888_to_rgb565_swab_line(dst, sbuf, linepixels);
+               else
+                       drm_fb_xrgb8888_to_rgb565_line(dst, sbuf, linepixels);
                vaddr += fb->pitches[0];
                dst += dst_pitch;
        }
@@ -321,7 +334,10 @@ void drm_fb_xrgb8888_to_rgb565_toio(void __iomem *dst, unsigned int dst_pitch,
 
        vaddr += clip_offset(clip, fb->pitches[0], sizeof(u32));
        for (y = 0; y < lines; y++) {
-               drm_fb_xrgb8888_to_rgb565_line(dbuf, vaddr, linepixels, swab);
+               if (swab)
+                       drm_fb_xrgb8888_to_rgb565_swab_line(dbuf, vaddr, linepixels);
+               else
+                       drm_fb_xrgb8888_to_rgb565_line(dbuf, vaddr, linepixels);
                memcpy_toio(dst, dbuf, dst_len);
                vaddr += fb->pitches[0];
                dst += dst_pitch;