fbdev: Support for byte-reversed framebuffer formats

Allow generic frame-buffer code to correctly write texts and blit images for
1, 2 and 4 bit per pixel frame-buffer organizations when pixels in bytes are
organized to in opposite order than bytes in long type.

Overhead should be reasonable.  If option is not selected, than compiler
should eliminate completely all overhead.

The feature is disabled at compile time if CONFIG_FB_CFB_REV_PIXELS_IN_BYTE is
not set.

[adaplas]
Convert helper functions to macros if feature is not enabled.

Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 8 deletions

diff --git a/drivers/video/cfbfillrect.c b/drivers/video/cfbfillrect.c
index 71623b4f8ca2..23d70a12e4da 100644
--- a/drivers/video/cfbfillrect.c
+++ b/drivers/video/cfbfillrect.c
@@ -36,15 +36,16 @@
      */
 
 static void
-bitfill_aligned(unsigned long __iomem *dst, int dst_idx, unsigned long pat, unsigned n, int bits)
+bitfill_aligned(unsigned long __iomem *dst, int dst_idx, unsigned long pat,
+                unsigned n, int bits, u32 bswapmask)
 {
         unsigned long first, last;
 
         if (!n)
                 return;
 
-        first = FB_SHIFT_HIGH(~0UL, dst_idx);
-        last = ~(FB_SHIFT_HIGH(~0UL, (dst_idx+n) % bits));
+        first = fb_shifted_pixels_mask_long(dst_idx, bswapmask);
+        last = ~fb_shifted_pixels_mask_long((dst_idx+n) % bits, bswapmask);
 
         if (dst_idx+n <= bits) {
                 // Single word
@@ -146,7 +147,8 @@ bitfill_unaligned(unsigned long __iomem *dst, int dst_idx, unsigned long pat,
      *  Aligned pattern invert using 32/64-bit memory accesses
      */
 static void
-bitfill_aligned_rev(unsigned long __iomem *dst, int dst_idx, unsigned long pat, unsigned n, int bits)
+bitfill_aligned_rev(unsigned long __iomem *dst, int dst_idx, unsigned long pat,
+                unsigned n, int bits, u32 bswapmask)
 {
         unsigned long val = pat, dat;
         unsigned long first, last;
@@ -154,8 +156,8 @@ bitfill_aligned_rev(unsigned long __iomem *dst, int dst_idx, unsigned long pat,
         if (!n)
                 return;
 
-        first = FB_SHIFT_HIGH(~0UL, dst_idx);
-        last = ~(FB_SHIFT_HIGH(~0UL, (dst_idx+n) % bits));
+        first = fb_shifted_pixels_mask_long(dst_idx, bswapmask);
+        last = ~fb_shifted_pixels_mask_long((dst_idx+n) % bits, bswapmask);
 
         if (dst_idx+n <= bits) {
                 // Single word
@@ -303,8 +305,10 @@ void cfb_fillrect(struct fb_info *p, const struct fb_fillrect *rect)
         if (p->fbops->fb_sync)
                 p->fbops->fb_sync(p);
         if (!left) {
+                u32 bswapmask = fb_compute_bswapmask(p);
                 void (*fill_op32)(unsigned long __iomem *dst, int dst_idx,
-                                  unsigned long pat, unsigned n, int bits) = NULL;
+                                  unsigned long pat, unsigned n, int bits,
+                                  u32 bswapmask) = NULL;
 
                 switch (rect->rop) {
                 case ROP_XOR:
@@ -321,7 +325,7 @@ void cfb_fillrect(struct fb_info *p, const struct fb_fillrect *rect)
                 while (height--) {
                         dst += dst_idx >> (ffs(bits) - 1);
                         dst_idx &= (bits - 1);
-                        fill_op32(dst, dst_idx, pat, width*bpp, bits);
+                        fill_op32(dst, dst_idx, pat, width*bpp, bits, bswapmask);
                         dst_idx += p->fix.line_length*8;
                 }
         } else {