The sys_copyarea() function performs the same operation as
cfb_copyarea() but using normal memory access instead of I/O
accessors.  Since the introduction of sys_copyarea(), there
have been two fixes to cfb_copyarea():

- 00a9d699 ("framebuffer: fix cfb_copyarea")
- 5b789da8 ("framebuffer: fix screen corruption when copying")

This patch incorporates the fixes into sys_copyarea() as well.

Signed-off-by: Mans Rullgard <m...@mansr.com>
---
 drivers/video/fbdev/core/syscopyarea.c | 137 ++++++++++++++++-----------------
 1 file changed, 65 insertions(+), 72 deletions(-)

diff --git a/drivers/video/fbdev/core/syscopyarea.c 
b/drivers/video/fbdev/core/syscopyarea.c
index 844a32f..67b4d6d 100644
--- a/drivers/video/fbdev/core/syscopyarea.c
+++ b/drivers/video/fbdev/core/syscopyarea.c
@@ -25,8 +25,8 @@
      */
 
 static void
-bitcpy(struct fb_info *p, unsigned long *dst, int dst_idx,
-               const unsigned long *src, int src_idx, int bits, unsigned n)
+bitcpy(struct fb_info *p, unsigned long *dst, unsigned dst_idx,
+       const unsigned long *src, unsigned src_idx, int bits, unsigned n)
 {
        unsigned long first, last;
        int const shift = dst_idx-src_idx;
@@ -86,15 +86,15 @@ bitcpy(struct fb_info *p, unsigned long *dst, int dst_idx,
                                first &= last;
                        if (shift > 0) {
                                /* Single source word */
-                               *dst = comp(*src >> right, *dst, first);
+                               *dst = comp(*src << left, *dst, first);
                        } else if (src_idx+n <= bits) {
                                /* Single source word */
-                               *dst = comp(*src << left, *dst, first);
+                               *dst = comp(*src >> right, *dst, first);
                        } else {
                                /* 2 source words */
                                d0 = *src++;
                                d1 = *src;
-                               *dst = comp(d0 << left | d1 >> right, *dst,
+                               *dst = comp(d0 >> right | d1 << left, *dst,
                                            first);
                        }
                } else {
@@ -109,13 +109,14 @@ bitcpy(struct fb_info *p, unsigned long *dst, int dst_idx,
                        /* Leading bits */
                        if (shift > 0) {
                                /* Single source word */
-                               *dst = comp(d0 >> right, *dst, first);
+                               *dst = comp(d0 << left, *dst, first);
                                dst++;
                                n -= bits - dst_idx;
                        } else {
                                /* 2 source words */
                                d1 = *src++;
-                               *dst = comp(d0 << left | *dst >> right, *dst, 
first);
+                               *dst = comp(d0 >> right | d1 << left, *dst,
+                                           first);
                                d0 = d1;
                                dst++;
                                n -= bits - dst_idx;
@@ -126,36 +127,36 @@ bitcpy(struct fb_info *p, unsigned long *dst, int dst_idx,
                        n /= bits;
                        while (n >= 4) {
                                d1 = *src++;
-                               *dst++ = d0 << left | d1 >> right;
+                               *dst++ = d0 >> right | d1 << left;
                                d0 = d1;
                                d1 = *src++;
-                               *dst++ = d0 << left | d1 >> right;
+                               *dst++ = d0 >> right | d1 << left;
                                d0 = d1;
                                d1 = *src++;
-                               *dst++ = d0 << left | d1 >> right;
+                               *dst++ = d0 >> right | d1 << left;
                                d0 = d1;
                                d1 = *src++;
-                               *dst++ = d0 << left | d1 >> right;
+                               *dst++ = d0 >> right | d1 << left;
                                d0 = d1;
                                n -= 4;
                        }
                        while (n--) {
                                d1 = *src++;
-                               *dst++ = d0 << left | d1 >> right;
+                               *dst++ = d0 >> right | d1 << left;
                                d0 = d1;
                        }
 
                        /* Trailing bits */
-                       if (last) {
-                               if (m <= right) {
+                       if (m) {
+                               if (m <= bits - right) {
                                        /* Single source word */
-                                       *dst = comp(d0 << left, *dst, last);
+                                       d0 >>= right;
                                } else {
                                        /* 2 source words */
                                        d1 = *src;
-                                       *dst = comp(d0 << left | d1 >> right,
-                                                   *dst, last);
+                                       d0 = d0 >> right | d1 << left;
                                }
+                               *dst = comp(d0, *dst, last);
                        }
                }
        }
@@ -166,40 +167,35 @@ bitcpy(struct fb_info *p, unsigned long *dst, int dst_idx,
      */
 
 static void
-bitcpy_rev(struct fb_info *p, unsigned long *dst, int dst_idx,
-               const unsigned long *src, int src_idx, int bits, unsigned n)
+bitcpy_rev(struct fb_info *p, unsigned long *dst, unsigned dst_idx,
+          const unsigned long *src, unsigned src_idx, unsigned bits,
+          unsigned n)
 {
        unsigned long first, last;
        int shift;
 
-       dst += (n-1)/bits;
-       src += (n-1)/bits;
-       if ((n-1) % bits) {
-               dst_idx += (n-1) % bits;
-               dst += dst_idx >> (ffs(bits) - 1);
-               dst_idx &= bits - 1;
-               src_idx += (n-1) % bits;
-               src += src_idx >> (ffs(bits) - 1);
-               src_idx &= bits - 1;
-       }
+       dst += (dst_idx + n - 1) / bits;
+       src += (src_idx + n - 1) / bits;
+       dst_idx = (dst_idx + n - 1) % bits;
+       src_idx = (src_idx + n - 1) % bits;
 
        shift = dst_idx-src_idx;
 
-       first = FB_SHIFT_LOW(p, ~0UL, bits - 1 - dst_idx);
-       last = ~(FB_SHIFT_LOW(p, ~0UL, bits - 1 - ((dst_idx-n) % bits)));
+       first = ~FB_SHIFT_LOW(p, ~0UL, (dst_idx + 1) % bits);
+       last = FB_SHIFT_LOW(p, ~0UL, (bits + dst_idx + 1 - n) % bits);
 
        if (!shift) {
                /* Same alignment for source and dest */
                if ((unsigned long)dst_idx+1 >= n) {
                        /* Single word */
-                       if (last)
-                               first &= last;
-                       *dst = comp(*src, *dst, first);
+                       if (first)
+                               last &= first;
+                       *dst = comp(*src, *dst, last);
                } else {
                        /* Multiple destination words */
 
                        /* Leading bits */
-                       if (first != ~0UL) {
+                       if (first) {
                                *dst = comp(*src, *dst, first);
                                dst--;
                                src--;
@@ -222,29 +218,29 @@ bitcpy_rev(struct fb_info *p, unsigned long *dst, int 
dst_idx,
                        while (n--)
                                *dst-- = *src--;
                        /* Trailing bits */
-                       if (last)
+                       if (last != -1UL)
                                *dst = comp(*src, *dst, last);
                }
        } else {
                /* Different alignment for source and dest */
 
-               int const left = -shift & (bits-1);
-               int const right = shift & (bits-1);
+               int const left = shift & (bits-1);
+               int const right = -shift & (bits-1);
 
                if ((unsigned long)dst_idx+1 >= n) {
                        /* Single destination word */
-                       if (last)
-                               first &= last;
+                       if (first)
+                               last &= first;
                        if (shift < 0) {
                                /* Single source word */
-                               *dst = comp(*src << left, *dst, first);
+                               *dst = comp(*src >> right, *dst, last);
                        } else if (1+(unsigned long)src_idx >= n) {
                                /* Single source word */
-                               *dst = comp(*src >> right, *dst, first);
+                               *dst = comp(*src << left, *dst, last);
                        } else {
                                /* 2 source words */
-                               *dst = comp(*src >> right | *(src-1) << left,
-                                           *dst, first);
+                               *dst = comp(*src << left | *(src-1) >> right,
+                                           *dst, last);
                        }
                } else {
                        /* Multiple destination words */
@@ -261,14 +257,18 @@ bitcpy_rev(struct fb_info *p, unsigned long *dst, int 
dst_idx,
                        /* Leading bits */
                        if (shift < 0) {
                                /* Single source word */
-                               *dst = comp(d0 << left, *dst, first);
+                               d1 = d0;
+                               d0 >>= right;
                        } else {
                                /* 2 source words */
                                d1 = *src--;
-                               *dst = comp(d0 >> right | d1 << left, *dst,
-                                           first);
-                               d0 = d1;
+                               d0 = d0 << left | d1 >> right;
                        }
+                       if (!first)
+                               *dst = d0;
+                       else
+                               *dst = comp(d0, *dst, first);
+                       d0 = d1;
                        dst--;
                        n -= dst_idx+1;
 
@@ -277,36 +277,36 @@ bitcpy_rev(struct fb_info *p, unsigned long *dst, int 
dst_idx,
                        n /= bits;
                        while (n >= 4) {
                                d1 = *src--;
-                               *dst-- = d0 >> right | d1 << left;
+                               *dst-- = d0 << left | d1 >> right;
                                d0 = d1;
                                d1 = *src--;
-                               *dst-- = d0 >> right | d1 << left;
+                               *dst-- = d0 << left | d1 >> right;
                                d0 = d1;
                                d1 = *src--;
-                               *dst-- = d0 >> right | d1 << left;
+                               *dst-- = d0 << left | d1 >> right;
                                d0 = d1;
                                d1 = *src--;
-                               *dst-- = d0 >> right | d1 << left;
+                               *dst-- = d0 << left | d1 >> right;
                                d0 = d1;
                                n -= 4;
                        }
                        while (n--) {
                                d1 = *src--;
-                               *dst-- = d0 >> right | d1 << left;
+                               *dst-- = d0 << left | d1 >> right;
                                d0 = d1;
                        }
 
                        /* Trailing bits */
-                       if (last) {
-                               if (m <= left) {
+                       if (m) {
+                               if (m <= bits - left) {
                                        /* Single source word */
-                                       *dst = comp(d0 >> right, *dst, last);
+                                       d0 <<= left;
                                } else {
                                        /* 2 source words */
                                        d1 = *src;
-                                       *dst = comp(d0 >> right | d1 << left,
-                                                   *dst, last);
+                                       d0 = d0 << left | d1 >> right;
                                }
+                               *dst = comp(d0, *dst, last);
                        }
                }
        }
@@ -317,9 +317,9 @@ void sys_copyarea(struct fb_info *p, const struct 
fb_copyarea *area)
        u32 dx = area->dx, dy = area->dy, sx = area->sx, sy = area->sy;
        u32 height = area->height, width = area->width;
        unsigned long const bits_per_line = p->fix.line_length*8u;
-       unsigned long *dst = NULL, *src = NULL;
+       unsigned long *base = NULL;
        int bits = BITS_PER_LONG, bytes = bits >> 3;
-       int dst_idx = 0, src_idx = 0, rev_copy = 0;
+       unsigned dst_idx = 0, src_idx = 0, rev_copy = 0;
 
        if (p->state != FBINFO_STATE_RUNNING)
                return;
@@ -334,8 +334,7 @@ void sys_copyarea(struct fb_info *p, const struct 
fb_copyarea *area)
 
        /* split the base of the framebuffer into a long-aligned address and
           the index of the first bit */
-       dst = src = (unsigned long *)((unsigned long)p->screen_base &
-                                     ~(bytes-1));
+       base = (unsigned long *)((unsigned long)p->screen_base & ~(bytes-1));
        dst_idx = src_idx = 8*((unsigned long)p->screen_base & (bytes-1));
        /* add offset of source and target area */
        dst_idx += dy*bits_per_line + dx*p->var.bits_per_pixel;
@@ -348,20 +347,14 @@ void sys_copyarea(struct fb_info *p, const struct 
fb_copyarea *area)
                while (height--) {
                        dst_idx -= bits_per_line;
                        src_idx -= bits_per_line;
-                       dst += dst_idx >> (ffs(bits) - 1);
-                       dst_idx &= (bytes - 1);
-                       src += src_idx >> (ffs(bits) - 1);
-                       src_idx &= (bytes - 1);
-                       bitcpy_rev(p, dst, dst_idx, src, src_idx, bits,
+                       bitcpy_rev(p, base + (dst_idx / bits), dst_idx % bits,
+                               base + (src_idx / bits), src_idx % bits, bits,
                                width*p->var.bits_per_pixel);
                }
        } else {
                while (height--) {
-                       dst += dst_idx >> (ffs(bits) - 1);
-                       dst_idx &= (bytes - 1);
-                       src += src_idx >> (ffs(bits) - 1);
-                       src_idx &= (bytes - 1);
-                       bitcpy(p, dst, dst_idx, src, src_idx, bits,
+                       bitcpy(p, base + (dst_idx / bits), dst_idx % bits,
+                               base + (src_idx / bits), src_idx % bits, bits,
                                width*p->var.bits_per_pixel);
                        dst_idx += bits_per_line;
                        src_idx += bits_per_line;
-- 
2.0.5

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