3.13.11.1 -stable review patch.  If anyone has any objections, please let me 
know.

------------------

From: Mikulas Patocka <mpato...@redhat.com>

commit 6b0df6827bb6fcacb158dff29ad0a62d6418b534 upstream.

The functions for data copying copyarea_foreward_8bpp and
copyarea_backward_8bpp are buggy, they produce screen corruption.

This patch fixes the functions and moves the logic to one function
"copyarea_8bpp". For simplicity, the function only handles copying that
is aligned on 8 pixes. If we copy an unaligned area, generic function
cfb_copyarea is used.

Signed-off-by: Mikulas Patocka <mpato...@redhat.com>
Signed-off-by: Tomi Valkeinen <tomi.valkei...@ti.com>
Signed-off-by: Kamal Mostafa <ka...@canonical.com>
---
 drivers/video/tgafb.c | 264 ++++++++++----------------------------------------
 1 file changed, 51 insertions(+), 213 deletions(-)

diff --git a/drivers/video/tgafb.c b/drivers/video/tgafb.c
index 6386233..412f4c1 100644
--- a/drivers/video/tgafb.c
+++ b/drivers/video/tgafb.c
@@ -1145,222 +1145,57 @@ copyarea_line_32bpp(struct fb_info *info, u32 dy, u32 
sy,
        __raw_writel(TGA_MODE_SBM_24BPP|TGA_MODE_SIMPLE, tga_regs+TGA_MODE_REG);
 }
 
-/* The general case of forward copy in 8bpp mode.  */
+/* The (almost) general case of backward copy in 8bpp mode.  */
 static inline void
-copyarea_foreward_8bpp(struct fb_info *info, u32 dx, u32 dy, u32 sx, u32 sy,
-                      u32 height, u32 width, u32 line_length)
+copyarea_8bpp(struct fb_info *info, u32 dx, u32 dy, u32 sx, u32 sy,
+             u32 height, u32 width, u32 line_length,
+             const struct fb_copyarea *area)
 {
        struct tga_par *par = (struct tga_par *) info->par;
-       unsigned long i, copied, left;
-       unsigned long dpos, spos, dalign, salign, yincr;
-       u32 smask_first, dmask_first, dmask_last;
-       int pixel_shift, need_prime, need_second;
-       unsigned long n64, n32, xincr_first;
+       unsigned i, yincr;
+       int depos, sepos, backward, last_step, step;
+       u32 mask_last;
+       unsigned n32;
        void __iomem *tga_regs;
        void __iomem *tga_fb;
 
-       yincr = line_length;
-       if (dy > sy) {
-               dy += height - 1;
-               sy += height - 1;
-               yincr = -yincr;
-       }
-
-       /* Compute the offsets and alignments in the frame buffer.
-          More than anything else, these control how we do copies.  */
-       dpos = dy * line_length + dx;
-       spos = sy * line_length + sx;
-       dalign = dpos & 7;
-       salign = spos & 7;
-       dpos &= -8;
-       spos &= -8;
-
-       /* Compute the value for the PIXELSHIFT register.  This controls
-          both non-co-aligned source and destination and copy direction.  */
-       if (dalign >= salign)
-               pixel_shift = dalign - salign;
-       else
-               pixel_shift = 8 - (salign - dalign);
-
-       /* Figure out if we need an additional priming step for the
-          residue register.  */
-       need_prime = (salign > dalign);
-       if (need_prime)
-               dpos -= 8;
-
-       /* Begin by copying the leading unaligned destination.  Copy enough
-          to make the next destination address 32-byte aligned.  */
-       copied = 32 - (dalign + (dpos & 31));
-       if (copied == 32)
-               copied = 0;
-       xincr_first = (copied + 7) & -8;
-       smask_first = dmask_first = (1ul << copied) - 1;
-       smask_first <<= salign;
-       dmask_first <<= dalign + need_prime*8;
-       if (need_prime && copied > 24)
-               copied -= 8;
-       left = width - copied;
-
-       /* Care for small copies.  */
-       if (copied > width) {
-               u32 t;
-               t = (1ul << width) - 1;
-               t <<= dalign + need_prime*8;
-               dmask_first &= t;
-               left = 0;
-       }
-
-       /* Attempt to use 64-byte copies.  This is only possible if the
-          source and destination are co-aligned at 64 bytes.  */
-       n64 = need_second = 0;
-       if ((dpos & 63) == (spos & 63)
-           && (height == 1 || line_length % 64 == 0)) {
-               /* We may need a 32-byte copy to ensure 64 byte alignment.  */
-               need_second = (dpos + xincr_first) & 63;
-               if ((need_second & 32) != need_second)
-                       printk(KERN_ERR "tgafb: need_second wrong\n");
-               if (left >= need_second + 64) {
-                       left -= need_second;
-                       n64 = left / 64;
-                       left %= 64;
-               } else
-                       need_second = 0;
-       }
-
-       /* Copy trailing full 32-byte sections.  This will be the main
-          loop if the 64 byte loop can't be used.  */
-       n32 = left / 32;
-       left %= 32;
-
-       /* Copy the trailing unaligned destination.  */
-       dmask_last = (1ul << left) - 1;
-
-       tga_regs = par->tga_regs_base;
-       tga_fb = par->tga_fb_base;
-
-       /* Set up the MODE and PIXELSHIFT registers.  */
-       __raw_writel(TGA_MODE_SBM_8BPP|TGA_MODE_COPY, tga_regs+TGA_MODE_REG);
-       __raw_writel(pixel_shift, tga_regs+TGA_PIXELSHIFT_REG);
-       wmb();
-
-       for (i = 0; i < height; ++i) {
-               unsigned long j;
-               void __iomem *sfb;
-               void __iomem *dfb;
-
-               sfb = tga_fb + spos;
-               dfb = tga_fb + dpos;
-               if (dmask_first) {
-                       __raw_writel(smask_first, sfb);
-                       wmb();
-                       __raw_writel(dmask_first, dfb);
-                       wmb();
-                       sfb += xincr_first;
-                       dfb += xincr_first;
-               }
-
-               if (need_second) {
-                       __raw_writel(0xffffffff, sfb);
-                       wmb();
-                       __raw_writel(0xffffffff, dfb);
-                       wmb();
-                       sfb += 32;
-                       dfb += 32;
-               }
-
-               if (n64 && (((unsigned long)sfb | (unsigned long)dfb) & 63))
-                       printk(KERN_ERR
-                              "tgafb: misaligned copy64 (s:%p, d:%p)\n",
-                              sfb, dfb);
-
-               for (j = 0; j < n64; ++j) {
-                       __raw_writel(sfb - tga_fb, tga_regs+TGA_COPY64_SRC);
-                       wmb();
-                       __raw_writel(dfb - tga_fb, tga_regs+TGA_COPY64_DST);
-                       wmb();
-                       sfb += 64;
-                       dfb += 64;
-               }
-
-               for (j = 0; j < n32; ++j) {
-                       __raw_writel(0xffffffff, sfb);
-                       wmb();
-                       __raw_writel(0xffffffff, dfb);
-                       wmb();
-                       sfb += 32;
-                       dfb += 32;
-               }
-
-               if (dmask_last) {
-                       __raw_writel(0xffffffff, sfb);
-                       wmb();
-                       __raw_writel(dmask_last, dfb);
-                       wmb();
-               }
-
-               spos += yincr;
-               dpos += yincr;
+       /* Do acceleration only if we are aligned on 8 pixels */
+       if ((dx | sx | width) & 7) {
+               cfb_copyarea(info, area);
+               return;
        }
 
-       /* Reset the MODE register to normal.  */
-       __raw_writel(TGA_MODE_SBM_8BPP|TGA_MODE_SIMPLE, tga_regs+TGA_MODE_REG);
-}
-
-/* The (almost) general case of backward copy in 8bpp mode.  */
-static inline void
-copyarea_backward_8bpp(struct fb_info *info, u32 dx, u32 dy, u32 sx, u32 sy,
-                      u32 height, u32 width, u32 line_length,
-                      const struct fb_copyarea *area)
-{
-       struct tga_par *par = (struct tga_par *) info->par;
-       unsigned long i, left, yincr;
-       unsigned long depos, sepos, dealign, sealign;
-       u32 mask_first, mask_last;
-       unsigned long n32;
-       void __iomem *tga_regs;
-       void __iomem *tga_fb;
-
        yincr = line_length;
        if (dy > sy) {
                dy += height - 1;
                sy += height - 1;
                yincr = -yincr;
        }
+       backward = dy == sy && dx > sx && dx < sx + width;
 
        /* Compute the offsets and alignments in the frame buffer.
           More than anything else, these control how we do copies.  */
-       depos = dy * line_length + dx + width;
-       sepos = sy * line_length + sx + width;
-       dealign = depos & 7;
-       sealign = sepos & 7;
-
-       /* ??? The documentation appears to be incorrect (or very
-          misleading) wrt how pixel shifting works in backward copy
-          mode, i.e. when PIXELSHIFT is negative.  I give up for now.
-          Do handle the common case of co-aligned backward copies,
-          but frob everything else back on generic code.  */
-       if (dealign != sealign) {
-               cfb_copyarea(info, area);
-               return;
-       }
-
-       /* We begin the copy with the trailing pixels of the
-          unaligned destination.  */
-       mask_first = (1ul << dealign) - 1;
-       left = width - dealign;
-
-       /* Care for small copies.  */
-       if (dealign > width) {
-               mask_first ^= (1ul << (dealign - width)) - 1;
-               left = 0;
-       }
+       depos = dy * line_length + dx;
+       sepos = sy * line_length + sx;
+       if (backward)
+               depos += width, sepos += width;
 
        /* Next copy full words at a time.  */
-       n32 = left / 32;
-       left %= 32;
+       n32 = width / 32;
+       last_step = width % 32;
 
        /* Finally copy the unaligned head of the span.  */
-       mask_last = -1 << (32 - left);
+       mask_last = (1ul << last_step) - 1;
+
+       if (!backward) {
+               step = 32;
+               last_step = 32;
+       } else {
+               step = -32;
+               last_step = -last_step;
+               sepos -= 32;
+               depos -= 32;
+       }
 
        tga_regs = par->tga_regs_base;
        tga_fb = par->tga_fb_base;
@@ -1377,25 +1212,33 @@ copyarea_backward_8bpp(struct fb_info *info, u32 dx, 
u32 dy, u32 sx, u32 sy,
 
                sfb = tga_fb + sepos;
                dfb = tga_fb + depos;
-               if (mask_first) {
-                       __raw_writel(mask_first, sfb);
-                       wmb();
-                       __raw_writel(mask_first, dfb);
-                       wmb();
-               }
 
-               for (j = 0; j < n32; ++j) {
-                       sfb -= 32;
-                       dfb -= 32;
+               for (j = 0; j < n32; j++) {
+                       if (j < 2 && j + 1 < n32 && !backward &&
+                           !(((unsigned long)sfb | (unsigned long)dfb) & 63)) {
+                               do {
+                                       __raw_writel(sfb - tga_fb, 
tga_regs+TGA_COPY64_SRC);
+                                       wmb();
+                                       __raw_writel(dfb - tga_fb, 
tga_regs+TGA_COPY64_DST);
+                                       wmb();
+                                       sfb += 64;
+                                       dfb += 64;
+                                       j += 2;
+                               } while (j + 1 < n32);
+                               j--;
+                               continue;
+                       }
                        __raw_writel(0xffffffff, sfb);
                        wmb();
                        __raw_writel(0xffffffff, dfb);
                        wmb();
+                       sfb += step;
+                       dfb += step;
                }
 
                if (mask_last) {
-                       sfb -= 32;
-                       dfb -= 32;
+                       sfb += last_step - step;
+                       dfb += last_step - step;
                        __raw_writel(mask_last, sfb);
                        wmb();
                        __raw_writel(mask_last, dfb);
@@ -1456,14 +1299,9 @@ tgafb_copyarea(struct fb_info *info, const struct 
fb_copyarea *area)
        else if (bpp == 32)
                cfb_copyarea(info, area);
 
-       /* Detect overlapping source and destination that requires
-          a backward copy.  */
-       else if (dy == sy && dx > sx && dx < sx + width)
-               copyarea_backward_8bpp(info, dx, dy, sx, sy, height,
-                                      width, line_length, area);
        else
-               copyarea_foreward_8bpp(info, dx, dy, sx, sy, height,
-                                      width, line_length);
+               copyarea_8bpp(info, dx, dy, sx, sy, height,
+                             width, line_length, area);
 }
 
 
-- 
1.9.1

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