/*
   *  Generic function for frame buffer with packed pixels of any depth.
   *
   *      Copyright (C)  1999-2005 James Simmons <jsimmons@www.infradead.org>
   *
   *  This file is subject to the terms and conditions of the GNU General Public
   *  License.  See the file COPYING in the main directory of this archive for
   *  more details.
   *
   * NOTES:
   *
   *  This is for cfb packed pixels. Iplan and such are incorporated in the
   *  drivers that need them.
   *
   *  FIXME
   *
   *  Also need to add code to deal with cards endians that are different than
   *  the native cpu endians. I also need to deal with MSB position in the word.
   *
   *  The two functions or copying forward and backward could be split up like
   *  the ones for filling, i.e. in aligned and unaligned versions. This would
   *  help moving some redundant computations and branches out of the loop, too.
   */

  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/string.h>
  #include <linux/fb.h>

  #include <asm/types.h>
  #include <asm/io.h>

  #include "fb_draw.h"

  
  #if BITS_PER_LONG == 32
  #  define FB_WRITEL fb_writel
  #  define FB_READL  fb_readl
  #else
  #  define FB_WRITEL fb_writeq
  #  define FB_READL  fb_readq
  #endif
  
      /*

       *  Generic bitwise copy algorithm
       */
  
  static void

  bitcpy(struct fb_info *p, unsigned long __iomem *dst, int dst_idx,
  		const unsigned long __iomem *src, 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_shifted_pixels_mask_long(p, dst_idx, bswapmask);
  	last = ~fb_shifted_pixels_mask_long(p, (dst_idx+n) % bits, bswapmask);

  
  	if (!shift) {
  		// Same alignment for source and dest
  
  		if (dst_idx+n <= bits) {
  			// Single word
  			if (last)
  				first &= last;
  			FB_WRITEL( comp( FB_READL(src), FB_READL(dst), first), dst);
  		} else {
  			// Multiple destination words
  
  			// Leading bits
  			if (first != ~0UL) {
  				FB_WRITEL( comp( FB_READL(src), FB_READL(dst), first), dst);
  				dst++;
  				src++;
  				n -= bits - dst_idx;
  			}
  
  			// Main chunk
  			n /= bits;
  			while (n >= 8) {
  				FB_WRITEL(FB_READL(src++), dst++);
  				FB_WRITEL(FB_READL(src++), dst++);
  				FB_WRITEL(FB_READL(src++), dst++);
  				FB_WRITEL(FB_READL(src++), dst++);
  				FB_WRITEL(FB_READL(src++), dst++);
  				FB_WRITEL(FB_READL(src++), dst++);
  				FB_WRITEL(FB_READL(src++), dst++);
  				FB_WRITEL(FB_READL(src++), dst++);
  				n -= 8;
  			}
  			while (n--)
  				FB_WRITEL(FB_READL(src++), dst++);
  
  			// Trailing bits
  			if (last)
  				FB_WRITEL( comp( FB_READL(src), FB_READL(dst), last), dst);
  		}
  	} else {

  		/* Different alignment for source and dest */

  		unsigned long d0, d1;
  		int m;

  
  		right = shift & (bits - 1);
  		left = -shift & (bits - 1);

  		bswapmask &= shift;

  
  		if (dst_idx+n <= bits) {
  			// Single destination word
  			if (last)
  				first &= last;

  			d0 = FB_READL(src);
  			d0 = fb_rev_pixels_in_long(d0, bswapmask);

  			if (shift > 0) {
  				// Single source word

  				d0 >>= right;

  			} else if (src_idx+n <= bits) {
  				// Single source word

  				d0 <<= left;

  			} else {
  				// 2 source words

  				d1 = FB_READL(src + 1);
  				d1 = fb_rev_pixels_in_long(d1, bswapmask);
  				d0 = d0<<left | d1>>right;

  			}

  			d0 = fb_rev_pixels_in_long(d0, bswapmask);
  			FB_WRITEL(comp(d0, FB_READL(dst), first), dst);

  		} else {
  			// Multiple destination words
  			/** We must always remember the last value read, because in case
  			SRC and DST overlap bitwise (e.g. when moving just one pixel in
  			1bpp), we always collect one full long for DST and that might
  			overlap with the current long from SRC. We store this value in
  			'd0'. */
  			d0 = FB_READL(src++);

  			d0 = fb_rev_pixels_in_long(d0, bswapmask);

  			// Leading bits
  			if (shift > 0) {
  				// Single source word

  				d1 = d0;
  				d0 >>= right;

  				dst++;
  				n -= bits - dst_idx;
  			} else {
  				// 2 source words
  				d1 = FB_READL(src++);

  				d1 = fb_rev_pixels_in_long(d1, bswapmask);
  
  				d0 = d0<<left | d1>>right;

  				dst++;
  				n -= bits - dst_idx;
  			}

  			d0 = fb_rev_pixels_in_long(d0, bswapmask);
  			FB_WRITEL(comp(d0, FB_READL(dst), first), dst);
  			d0 = d1;

  
  			// Main chunk
  			m = n % bits;
  			n /= bits;

  			while ((n >= 4) && !bswapmask) {

  				d1 = FB_READL(src++);
  				FB_WRITEL(d0 << left | d1 >> right, dst++);
  				d0 = d1;
  				d1 = FB_READL(src++);
  				FB_WRITEL(d0 << left | d1 >> right, dst++);
  				d0 = d1;
  				d1 = FB_READL(src++);
  				FB_WRITEL(d0 << left | d1 >> right, dst++);
  				d0 = d1;
  				d1 = FB_READL(src++);
  				FB_WRITEL(d0 << left | d1 >> right, dst++);
  				d0 = d1;
  				n -= 4;
  			}
  			while (n--) {
  				d1 = FB_READL(src++);

  				d1 = fb_rev_pixels_in_long(d1, bswapmask);
  				d0 = d0 << left | d1 >> right;
  				d0 = fb_rev_pixels_in_long(d0, bswapmask);
  				FB_WRITEL(d0, dst++);

  				d0 = d1;
  			}
  
  			// Trailing bits
  			if (last) {
  				if (m <= right) {
  					// Single source word

  					d0 <<= left;

  				} else {
  					// 2 source words
  					d1 = FB_READL(src);

  					d1 = fb_rev_pixels_in_long(d1,
  								bswapmask);
  					d0 = d0<<left | d1>>right;

  				}

  				d0 = fb_rev_pixels_in_long(d0, bswapmask);
  				FB_WRITEL(comp(d0, FB_READL(dst), last), dst);

  			}
  		}
  	}
  }
  
      /*
       *  Generic bitwise copy algorithm, operating backward
       */
  
  static void

  bitcpy_rev(struct fb_info *p, unsigned long __iomem *dst, int dst_idx,
  		const unsigned long __iomem *src, int src_idx, int bits,
  		unsigned n, u32 bswapmask)

  {
  	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;
  	}
  
  	shift = dst_idx-src_idx;

  	first = fb_shifted_pixels_mask_long(p, bits - 1 - dst_idx, bswapmask);
  	last = ~fb_shifted_pixels_mask_long(p, bits - 1 - ((dst_idx-n) % bits),
  					    bswapmask);

  
  	if (!shift) {
  		// Same alignment for source and dest
  
  		if ((unsigned long)dst_idx+1 >= n) {
  			// Single word
  			if (last)
  				first &= last;
  			FB_WRITEL( comp( FB_READL(src), FB_READL(dst), first), dst);
  		} else {
  			// Multiple destination words
  
  			// Leading bits
  			if (first != ~0UL) {
  				FB_WRITEL( comp( FB_READL(src), FB_READL(dst), first), dst);
  				dst--;
  				src--;
  				n -= dst_idx+1;
  			}
  
  			// Main chunk
  			n /= bits;
  			while (n >= 8) {
  				FB_WRITEL(FB_READL(src--), dst--);
  				FB_WRITEL(FB_READL(src--), dst--);
  				FB_WRITEL(FB_READL(src--), dst--);
  				FB_WRITEL(FB_READL(src--), dst--);
  				FB_WRITEL(FB_READL(src--), dst--);
  				FB_WRITEL(FB_READL(src--), dst--);
  				FB_WRITEL(FB_READL(src--), dst--);
  				FB_WRITEL(FB_READL(src--), dst--);
  				n -= 8;
  			}
  			while (n--)
  				FB_WRITEL(FB_READL(src--), dst--);
  
  			// Trailing bits
  			if (last)
  				FB_WRITEL( comp( FB_READL(src), FB_READL(dst), last), dst);
  		}
  	} else {
  		// Different alignment for source and dest

  		unsigned long d0, d1;
  		int m;

  
  		int const left = -shift & (bits-1);
  		int const right = shift & (bits-1);

  		bswapmask &= shift;

  
  		if ((unsigned long)dst_idx+1 >= n) {
  			// Single destination word
  			if (last)
  				first &= last;

  			d0 = FB_READL(src);

  			if (shift < 0) {
  				// Single source word

  				d0 <<= left;

  			} else if (1+(unsigned long)src_idx >= n) {
  				// Single source word

  				d0 >>= right;

  			} else {
  				// 2 source words

  				d1 = FB_READL(src - 1);
  				d1 = fb_rev_pixels_in_long(d1, bswapmask);
  				d0 = d0>>right | d1<<left;

  			}

  			d0 = fb_rev_pixels_in_long(d0, bswapmask);
  			FB_WRITEL(comp(d0, FB_READL(dst), first), dst);

  		} else {
  			// Multiple destination words
  			/** We must always remember the last value read, because in case
  			SRC and DST overlap bitwise (e.g. when moving just one pixel in
  			1bpp), we always collect one full long for DST and that might
  			overlap with the current long from SRC. We store this value in
  			'd0'. */

  
  			d0 = FB_READL(src--);

  			d0 = fb_rev_pixels_in_long(d0, bswapmask);

  			// Leading bits
  			if (shift < 0) {
  				// Single source word

  				d1 = d0;
  				d0 <<= left;

  			} else {
  				// 2 source words
  				d1 = FB_READL(src--);

  				d1 = fb_rev_pixels_in_long(d1, bswapmask);
  				d0 = d0>>right | d1<<left;

  			}

  			d0 = fb_rev_pixels_in_long(d0, bswapmask);
  			FB_WRITEL(comp(d0, FB_READL(dst), first), dst);
  			d0 = d1;

  			dst--;
  			n -= dst_idx+1;
  
  			// Main chunk
  			m = n % bits;
  			n /= bits;

  			while ((n >= 4) && !bswapmask) {

  				d1 = FB_READL(src--);
  				FB_WRITEL(d0 >> right | d1 << left, dst--);
  				d0 = d1;
  				d1 = FB_READL(src--);
  				FB_WRITEL(d0 >> right | d1 << left, dst--);
  				d0 = d1;
  				d1 = FB_READL(src--);
  				FB_WRITEL(d0 >> right | d1 << left, dst--);
  				d0 = d1;
  				d1 = FB_READL(src--);
  				FB_WRITEL(d0 >> right | d1 << left, dst--);
  				d0 = d1;
  				n -= 4;
  			}
  			while (n--) {
  				d1 = FB_READL(src--);

  				d1 = fb_rev_pixels_in_long(d1, bswapmask);
  				d0 = d0 >> right | d1 << left;
  				d0 = fb_rev_pixels_in_long(d0, bswapmask);
  				FB_WRITEL(d0, dst--);

  				d0 = d1;
  			}
  
  			// Trailing bits
  			if (last) {
  				if (m <= left) {
  					// Single source word

  					d0 >>= right;

  				} else {
  					// 2 source words
  					d1 = FB_READL(src);

  					d1 = fb_rev_pixels_in_long(d1,
  								bswapmask);
  					d0 = d0>>right | d1<<left;

  				}

  				d0 = fb_rev_pixels_in_long(d0, bswapmask);
  				FB_WRITEL(comp(d0, FB_READL(dst), last), dst);

  			}
  		}
  	}
  }
  
  void cfb_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 __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;

  	/* if the beginning of the target area might overlap with the end of
  	the source area, be have to copy the area reverse. */
  	if ((dy == sy && dx > sx) || (dy > sy)) {
  		dy += height;
  		sy += height;
  		rev_copy = 1;
  	}
  
  	// split the base of the framebuffer into a long-aligned address and the
  	// index of the first bit
  	dst = src = (unsigned long __iomem *)((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;
  	src_idx += sy*bits_per_line + sx*p->var.bits_per_pixel;
  
  	if (p->fbops->fb_sync)
  		p->fbops->fb_sync(p);
  
  	if (rev_copy) {
  		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,

  				width*p->var.bits_per_pixel, bswapmask);

  		}
  	} 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,

  				width*p->var.bits_per_pixel, bswapmask);

  			dst_idx += bits_per_line;
  			src_idx += bits_per_line;
  		}
  	}
  }
  
  EXPORT_SYMBOL(cfb_copyarea);
  
  MODULE_AUTHOR("James Simmons <jsimmons@users.sf.net>");
  MODULE_DESCRIPTION("Generic software accelerated copyarea");
  MODULE_LICENSE("GPL");