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>

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index f1cc8996456fe05b888bf5731188e7db494db192..5c1ef09380063c9487881b9feaaa25095211fa04 100644 (file)
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -103,6 +103,15 @@ config FB_CFB_IMAGEBLIT
          blitting. This is used by drivers that don't provide their own
          (accelerated) version.
 
+config FB_CFB_REV_PIXELS_IN_BYTE
+       bool
+       depends on FB
+       default n
+       ---help---
+         Allow generic frame-buffer functions to work on displays with 1, 2
+         and 4 bits per pixel depths which has opposite order of pixels in
+         byte order to bytes in long order.
+
 config FB_SYS_FILLRECT
        tristate
        depends on FB

diff --git a/drivers/video/cfbcopyarea.c b/drivers/video/cfbcopyarea.c
index 032210f45be37a539831030b63d64c1a5d3df61a..1c67885a1f4f2da9eaa8487ab5136182c8a965a4 100644 (file)
--- a/drivers/video/cfbcopyarea.c
+++ b/drivers/video/cfbcopyarea.c
@@ -45,14 +45,14 @@
 
 static void
 bitcpy(unsigned long __iomem *dst, int dst_idx, const unsigned long __iomem *src,
-       int src_idx, int bits, unsigned n)
+       int src_idx, int bits, unsigned n, u32 bswapmask)
 {
        unsigned long first, last;
        int const shift = dst_idx-src_idx;
        int left, right;
 
-       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 (!shift) {
                // Same alignment for source and dest
@@ -185,7 +185,7 @@ bitcpy(unsigned long __iomem *dst, int dst_idx, const unsigned long __iomem *src
 
 static void
 bitcpy_rev(unsigned long __iomem *dst, int dst_idx, const unsigned long __iomem *src,
-               int src_idx, int bits, unsigned n)
+               int src_idx, int bits, unsigned n, u32 bswapmask)
 {
        unsigned long first, last;
        int shift;
@@ -203,8 +203,8 @@ bitcpy_rev(unsigned long __iomem *dst, int dst_idx, const unsigned long __iomem
 
        shift = dst_idx-src_idx;
 
-       first = FB_SHIFT_LOW(~0UL, bits - 1 - dst_idx);
-       last = ~(FB_SHIFT_LOW(~0UL, bits - 1 - ((dst_idx-n) % bits)));
+       first = fb_shifted_pixels_mask_long(bits - 1 - dst_idx, bswapmask);
+       last = ~fb_shifted_pixels_mask_long(bits - 1 - ((dst_idx-n) % bits), bswapmask);
 
        if (!shift) {
                // Same alignment for source and dest
@@ -336,6 +336,7 @@ void cfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
        unsigned long __iomem *dst = NULL, *src = NULL;
        int bits = BITS_PER_LONG, bytes = bits >> 3;
        int dst_idx = 0, src_idx = 0, rev_copy = 0;
+       u32 bswapmask = fb_compute_bswapmask(p);
 
        if (p->state != FBINFO_STATE_RUNNING)
                return;
@@ -368,7 +369,7 @@ void cfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
                        src += src_idx >> (ffs(bits) - 1);
                        src_idx &= (bytes - 1);
                        bitcpy_rev(dst, dst_idx, src, src_idx, bits,
-                               width*p->var.bits_per_pixel);
+                               width*p->var.bits_per_pixel, bswapmask);
                }
        } else {
                while (height--) {
@@ -377,7 +378,7 @@ void cfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
                        src += src_idx >> (ffs(bits) - 1);
                        src_idx &= (bytes - 1);
                        bitcpy(dst, dst_idx, src, src_idx, bits,
-                               width*p->var.bits_per_pixel);
+                               width*p->var.bits_per_pixel, bswapmask);
                        dst_idx += bits_per_line;
                        src_idx += bits_per_line;
                }

diff --git a/drivers/video/cfbfillrect.c b/drivers/video/cfbfillrect.c
index 71623b4f8ca26581dbf4f8258734685fbd55e079..23d70a12e4daa273bbb16280d3c8f26c682901f2 100644 (file)
--- 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 {

diff --git a/drivers/video/cfbimgblt.c b/drivers/video/cfbimgblt.c
index 261004473c8e76b8e446317a7dfec8bbb9342517..f598907b42adfa71adaa5f237e07e7ab8cd1757d 100644 (file)
--- a/drivers/video/cfbimgblt.c
+++ b/drivers/video/cfbimgblt.c
@@ -33,6 +33,7 @@
 #include <linux/string.h>
 #include <linux/fb.h>
 #include <asm/types.h>
+#include "fb_draw.h"
 
 #define DEBUG
 
@@ -87,6 +88,7 @@ static inline void color_imageblit(const struct fb_image *image,
        u32 null_bits = 32 - bpp;
        u32 *palette = (u32 *) p->pseudo_palette;
        const u8 *src = image->data;
+       u32 bswapmask = fb_compute_bswapmask(p);
 
        dst2 = (u32 __iomem *) dst1;
        for (i = image->height; i--; ) {
@@ -96,7 +98,7 @@ static inline void color_imageblit(const struct fb_image *image,
                val = 0;
                
                if (start_index) {
-                       u32 start_mask = ~(FB_SHIFT_HIGH(~(u32)0, start_index));
+                       u32 start_mask = ~fb_shifted_pixels_mask_u32(start_index, bswapmask);
                        val = FB_READL(dst) & start_mask;
                        shift = start_index;
                }
@@ -107,7 +109,7 @@ static inline void color_imageblit(const struct fb_image *image,
                        else
                                color = *src;
                        color <<= FB_LEFT_POS(bpp);
-                       val |= FB_SHIFT_HIGH(color, shift);
+                       val |= FB_SHIFT_HIGH(color, shift ^ bswapmask);
                        if (shift >= null_bits) {
                                FB_WRITEL(val, dst++);
        
@@ -119,7 +121,7 @@ static inline void color_imageblit(const struct fb_image *image,
                        src++;
                }
                if (shift) {
-                       u32 end_mask = FB_SHIFT_HIGH(~(u32)0, shift);
+                       u32 end_mask = fb_shifted_pixels_mask_u32(shift, bswapmask);
 
                        FB_WRITEL((FB_READL(dst) & end_mask) | val, dst);
                }
@@ -147,7 +149,8 @@ static inline void slow_imageblit(const struct fb_image *image, struct fb_info *
        u32 spitch = (image->width+7)/8;
        const u8 *src = image->data, *s;
        u32 i, j, l;
-       
+       u32 bswapmask = fb_compute_bswapmask(p);
+
        dst2 = (u32 __iomem *) dst1;
        fgcolor <<= FB_LEFT_POS(bpp);
        bgcolor <<= FB_LEFT_POS(bpp);
@@ -161,7 +164,7 @@ static inline void slow_imageblit(const struct fb_image *image, struct fb_info *
 
                /* write leading bits */
                if (start_index) {
-                       u32 start_mask = ~(FB_SHIFT_HIGH(~(u32)0,start_index));
+                       u32 start_mask = ~fb_shifted_pixels_mask_u32(start_index, bswapmask);
                        val = FB_READL(dst) & start_mask;
                        shift = start_index;
                }
@@ -169,7 +172,7 @@ static inline void slow_imageblit(const struct fb_image *image, struct fb_info *
                while (j--) {
                        l--;
                        color = (*s & (1 << l)) ? fgcolor : bgcolor;
-                       val |= FB_SHIFT_HIGH(color, shift);
+                       val |= FB_SHIFT_HIGH(color, shift ^ bswapmask);
                        
                        /* Did the bitshift spill bits to the next long? */
                        if (shift >= null_bits) {
@@ -184,7 +187,7 @@ static inline void slow_imageblit(const struct fb_image *image, struct fb_info *
 
                /* write trailing bits */
                if (shift) {
-                       u32 end_mask = FB_SHIFT_HIGH(~(u32)0, shift);
+                       u32 end_mask = fb_shifted_pixels_mask_u32(shift, bswapmask);
 
                        FB_WRITEL((FB_READL(dst) & end_mask) | val, dst);
                }

diff --git a/drivers/video/fb_draw.h b/drivers/video/fb_draw.h
index c5c45203833b8a17143dd1df49df32008b7ad142..816843f06bb7b19c46b81d38d5c2da2575054d2a 100644 (file)
--- a/drivers/video/fb_draw.h
+++ b/drivers/video/fb_draw.h
@@ -2,6 +2,7 @@
 #define _FB_DRAW_H
 
 #include <asm/types.h>
+#include <linux/fb.h>
 
     /*
      *  Compose two values, using a bitmask as decision value
@@ -69,4 +70,71 @@ pixel_to_pat( u32 bpp, u32 pixel)
     }
 }
 #endif
+
+#ifdef CONFIG_FB_CFB_REV_PIXELS_IN_BYTE
+
+static inline u32 fb_shifted_pixels_mask_u32(u32 index, u32 bswapmask)
+{
+       u32 mask;
+
+       if (!bswapmask) {
+               mask = FB_SHIFT_HIGH(~(u32)0, index);
+       } else {
+               mask = 0xff << FB_LEFT_POS(8);
+               mask = FB_SHIFT_LOW(mask, index & (bswapmask)) & mask;
+               mask = FB_SHIFT_HIGH(mask, index & ~(bswapmask));
+#if defined(__i386__) || defined(__x86_64__)
+               /* Shift argument is limited to 0 - 31 on x86 based CPU's */
+               if(index + bswapmask < 32)
+#endif
+                       mask |= FB_SHIFT_HIGH(~(u32)0,
+                                       (index + bswapmask) & ~(bswapmask));
+       }
+       return mask;
+}
+
+static inline unsigned long fb_shifted_pixels_mask_long(u32 index, u32 bswapmask)
+{
+       unsigned long mask;
+
+       if (!bswapmask) {
+               mask = FB_SHIFT_HIGH(~0UL, index);
+       } else {
+               mask = 0xff << FB_LEFT_POS(8);
+               mask = FB_SHIFT_LOW(mask, index & (bswapmask)) & mask;
+               mask = FB_SHIFT_HIGH(mask, index & ~(bswapmask));
+#if defined(__i386__) || defined(__x86_64__)
+               /* Shift argument is limited to 0 - 31 on x86 based CPU's */
+               if(index + bswapmask < BITS_PER_LONG)
+#endif
+                       mask |= FB_SHIFT_HIGH(~0UL,
+                                       (index + bswapmask) & ~(bswapmask));
+       }
+       return mask;
+}
+
+
+static inline u32 fb_compute_bswapmask(struct fb_info *info)
+{
+       u32 bswapmask = 0;
+       unsigned bpp = info->var.bits_per_pixel;
+
+       if ((bpp < 8) && (info->var.nonstd & FB_NONSTD_REV_PIX_IN_B)) {
+               /*
+                * Reversed order of pixel layout in bytes
+                * works only for 1, 2 and 4 bpp
+                */
+               bswapmask = 7 - bpp + 1;
+       }
+       return bswapmask;
+}
+
+#else /* CONFIG_FB_CFB_REV_PIXELS_IN_BYTE */
+
+#define fb_shifted_pixels_mask_u32(i, b) FB_SHIFT_HIGH(~(u32)0, (i))
+#define fb_shifted_pixels_mask_long(i, b) FB_SHIFT_HIGH(~0UL, (i))
+#define fb_compute_bswapmask(...) 0
+
+#endif  /* CONFIG_FB_CFB_REV_PIXELS_IN_BYTE */
+
 #endif /* FB_DRAW_H */

diff --git a/include/linux/fb.h b/include/linux/fb.h
index cec54106aa8730ea7e82cdbefa0bbfe97f015ffe..b39395caa46037c1e5dfda297e5102e374a08a0c 100644 (file)
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -180,6 +180,7 @@ struct fb_bitfield {
 };
 
 #define FB_NONSTD_HAM          1       /* Hold-And-Modify (HAM)        */
+#define FB_NONSTD_REV_PIX_IN_B 2       /* order of pixels in each byte is reversed */
 
 #define FB_ACTIVATE_NOW                0       /* set values immediately (or vbl)*/
 #define FB_ACTIVATE_NXTOPEN    1       /* activate on next open        */