drm/format-helper: Add drm_fb_swab()

This replaces drm_fb_swab16() with drm_fb_swab() supporting 16 and 32-bit.
Also make pixel line caching optional.

v2:
- Bail out on cpp != 2 && 4 (Sam)

Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200509141619.32970-8-noralf@tronnes.org

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index 3b818f2..c043ca3 100644 (file)
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -79,39 +79,60 @@ void drm_fb_memcpy_dstclip(void __iomem *dst, void *vaddr,
 EXPORT_SYMBOL(drm_fb_memcpy_dstclip);
 
 /**
- * drm_fb_swab16 - Swap bytes into clip buffer
- * @dst: RGB565 destination buffer
- * @vaddr: RGB565 source buffer
+ * drm_fb_swab - Swap bytes into clip buffer
+ * @dst: Destination buffer
+ * @src: Source buffer
  * @fb: DRM framebuffer
  * @clip: Clip rectangle area to copy
+ * @cached: Source buffer is mapped cached (eg. not write-combined)
+ *
+ * If @cached is false a temporary buffer is used to cache one pixel line at a
+ * time to speed up slow uncached reads.
+ *
+ * This function does not apply clipping on dst, i.e. the destination
+ * is a small buffer containing the clip rect only.
  */
-void drm_fb_swab16(u16 *dst, void *vaddr, struct drm_framebuffer *fb,
-                  struct drm_rect *clip)
+void drm_fb_swab(void *dst, void *src, struct drm_framebuffer *fb,
+                struct drm_rect *clip, bool cached)
 {
-       size_t len = (clip->x2 - clip->x1) * sizeof(u16);
+       u8 cpp = fb->format->cpp[0];
+       size_t len = drm_rect_width(clip) * cpp;
+       u16 *src16, *dst16 = dst;
+       u32 *src32, *dst32 = dst;
        unsigned int x, y;
-       u16 *src, *buf;
+       void *buf = NULL;
 
-       /*
-        * The cma memory is write-combined so reads are uncached.
-        * Speed up by fetching one line at a time.
-        */
-       buf = kmalloc(len, GFP_KERNEL);
-       if (!buf)
+       if (WARN_ON_ONCE(cpp != 2 && cpp != 4))
                return;
 
+       if (!cached)
+               buf = kmalloc(len, GFP_KERNEL);
+
+       src += clip_offset(clip, fb->pitches[0], cpp);
+
        for (y = clip->y1; y < clip->y2; y++) {
-               src = vaddr + (y * fb->pitches[0]);
-               src += clip->x1;
-               memcpy(buf, src, len);
-               src = buf;
-               for (x = clip->x1; x < clip->x2; x++)
-                       *dst++ = swab16(*src++);
+               if (buf) {
+                       memcpy(buf, src, len);
+                       src16 = buf;
+                       src32 = buf;
+               } else {
+                       src16 = src;
+                       src32 = src;
+               }
+
+               for (x = clip->x1; x < clip->x2; x++) {
+                       if (cpp == 4)
+                               *dst32++ = swab32(*src32++);
+                       else
+                               *dst16++ = swab16(*src16++);
+               }
+
+               src += fb->pitches[0];
        }
 
        kfree(buf);
 }
-EXPORT_SYMBOL(drm_fb_swab16);
+EXPORT_SYMBOL(drm_fb_swab);
 
 static void drm_fb_xrgb8888_to_rgb565_line(u16 *dbuf, u32 *sbuf,
                                           unsigned int pixels,

diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c
index bb27c82..fd8d672 100644 (file)
--- a/drivers/gpu/drm/drm_mipi_dbi.c
+++ b/drivers/gpu/drm/drm_mipi_dbi.c
@@ -217,7 +217,7 @@ int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
        switch (fb->format->format) {
        case DRM_FORMAT_RGB565:
                if (swap)
-                       drm_fb_swab16(dst, src, fb, clip);
+                       drm_fb_swab(dst, src, fb, clip, !import_attach);
                else
                        drm_fb_memcpy(dst, src, fb, clip);
                break;

diff --git a/include/drm/drm_format_helper.h b/include/drm/drm_format_helper.h
index ac220aa..5f9e370 100644 (file)
--- a/include/drm/drm_format_helper.h
+++ b/include/drm/drm_format_helper.h
@@ -14,8 +14,8 @@ void drm_fb_memcpy(void *dst, void *vaddr, struct drm_framebuffer *fb,
 void drm_fb_memcpy_dstclip(void __iomem *dst, void *vaddr,
                           struct drm_framebuffer *fb,
                           struct drm_rect *clip);
-void drm_fb_swab16(u16 *dst, void *vaddr, struct drm_framebuffer *fb,
-                  struct drm_rect *clip);
+void drm_fb_swab(void *dst, void *src, struct drm_framebuffer *fb,
+                struct drm_rect *clip, bool cached);
 void drm_fb_xrgb8888_to_rgb565(void *dst, void *vaddr,
                               struct drm_framebuffer *fb,
                               struct drm_rect *clip, bool swab);