/*
   *  Generic 1-bit or 8-bit source to 1-32 bit destination expansion
   *  for frame buffer located in system RAM with packed pixels of any depth.
   *
   *  Based almost entirely on cfbimgblt.c
   *
   *      Copyright (C)  April 2007 Antonino Daplas <adaplas@pol.net>
   *
   *  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.
   */
  #include <linux/module.h>
  #include <linux/string.h>
  #include <linux/fb.h>
  #include <asm/types.h>
  
  #define DEBUG
  
  #ifdef DEBUG
  #define DPRINTK(fmt, args...) printk(KERN_DEBUG "%s: " fmt,__func__,## args)
  #else
  #define DPRINTK(fmt, args...)
  #endif
  
  static const u32 cfb_tab8_be[] = {
      0x00000000,0x000000ff,0x0000ff00,0x0000ffff,
      0x00ff0000,0x00ff00ff,0x00ffff00,0x00ffffff,
      0xff000000,0xff0000ff,0xff00ff00,0xff00ffff,
      0xffff0000,0xffff00ff,0xffffff00,0xffffffff
  };
  
  static const u32 cfb_tab8_le[] = {
      0x00000000,0xff000000,0x00ff0000,0xffff0000,
      0x0000ff00,0xff00ff00,0x00ffff00,0xffffff00,
      0x000000ff,0xff0000ff,0x00ff00ff,0xffff00ff,
      0x0000ffff,0xff00ffff,0x00ffffff,0xffffffff
  };
  
  static const u32 cfb_tab16_be[] = {
      0x00000000, 0x0000ffff, 0xffff0000, 0xffffffff
  };
  
  static const u32 cfb_tab16_le[] = {
      0x00000000, 0xffff0000, 0x0000ffff, 0xffffffff
  };
  
  static const u32 cfb_tab32[] = {
  	0x00000000, 0xffffffff
  };
  
  static void color_imageblit(const struct fb_image *image, struct fb_info *p,
  			    void *dst1, u32 start_index, u32 pitch_index)
  {
  	/* Draw the penguin */
  	u32 *dst, *dst2;
  	u32 color = 0, val, shift;
  	int i, n, bpp = p->var.bits_per_pixel;
  	u32 null_bits = 32 - bpp;
  	u32 *palette = (u32 *) p->pseudo_palette;
  	const u8 *src = image->data;
  
  	dst2 = dst1;
  	for (i = image->height; i--; ) {
  		n = image->width;
  		dst = dst1;
  		shift = 0;
  		val = 0;
  
  		if (start_index) {
  			u32 start_mask = ~(FB_SHIFT_HIGH(p, ~(u32)0,
  							 start_index));
  			val = *dst & start_mask;
  			shift = start_index;
  		}
  		while (n--) {
  			if (p->fix.visual == FB_VISUAL_TRUECOLOR ||
  			    p->fix.visual == FB_VISUAL_DIRECTCOLOR )
  				color = palette[*src];
  			else
  				color = *src;
  			color <<= FB_LEFT_POS(p, bpp);
  			val |= FB_SHIFT_HIGH(p, color, shift);
  			if (shift >= null_bits) {
  				*dst++ = val;
  
  				val = (shift == null_bits) ? 0 :
  					FB_SHIFT_LOW(p, color, 32 - shift);
  			}
  			shift += bpp;
  			shift &= (32 - 1);
  			src++;
  		}
  		if (shift) {
  			u32 end_mask = FB_SHIFT_HIGH(p, ~(u32)0, shift);
  
  			*dst &= end_mask;
  			*dst |= val;
  		}
  		dst1 += p->fix.line_length;
  		if (pitch_index) {
  			dst2 += p->fix.line_length;
  			dst1 = (u8 *)((long)dst2 & ~(sizeof(u32) - 1));
  
  			start_index += pitch_index;
  			start_index &= 32 - 1;
  		}
  	}
  }
  
  static void slow_imageblit(const struct fb_image *image, struct fb_info *p,
  				  void *dst1, u32 fgcolor, u32 bgcolor,
  				  u32 start_index, u32 pitch_index)
  {
  	u32 shift, color = 0, bpp = p->var.bits_per_pixel;
  	u32 *dst, *dst2;
  	u32 val, pitch = p->fix.line_length;
  	u32 null_bits = 32 - bpp;
  	u32 spitch = (image->width+7)/8;
  	const u8 *src = image->data, *s;
  	u32 i, j, l;
  
  	dst2 = dst1;
  	fgcolor <<= FB_LEFT_POS(p, bpp);
  	bgcolor <<= FB_LEFT_POS(p, bpp);
  
  	for (i = image->height; i--; ) {
  		shift = val = 0;
  		l = 8;
  		j = image->width;
  		dst = dst1;
  		s = src;
  
  		/* write leading bits */
  		if (start_index) {
  			u32 start_mask = ~(FB_SHIFT_HIGH(p, ~(u32)0,
  							 start_index));
  			val = *dst & start_mask;
  			shift = start_index;
  		}
  
  		while (j--) {
  			l--;
  			color = (*s & (1 << l)) ? fgcolor : bgcolor;
  			val |= FB_SHIFT_HIGH(p, color, shift);
  
  			/* Did the bitshift spill bits to the next long? */
  			if (shift >= null_bits) {
  				*dst++ = val;
  				val = (shift == null_bits) ? 0 :
  					FB_SHIFT_LOW(p, color, 32 - shift);
  			}
  			shift += bpp;
  			shift &= (32 - 1);
  			if (!l) { l = 8; s++; }
  		}
  
  		/* write trailing bits */
   		if (shift) {
  			u32 end_mask = FB_SHIFT_HIGH(p, ~(u32)0, shift);
  
  			*dst &= end_mask;
  			*dst |= val;
  		}
  
  		dst1 += pitch;
  		src += spitch;
  		if (pitch_index) {
  			dst2 += pitch;
  			dst1 = (u8 *)((long)dst2 & ~(sizeof(u32) - 1));
  			start_index += pitch_index;
  			start_index &= 32 - 1;
  		}
  
  	}
  }
  
  /*
   * fast_imageblit - optimized monochrome color expansion
   *
   * Only if:  bits_per_pixel == 8, 16, or 32
   *           image->width is divisible by pixel/dword (ppw);
   *           fix->line_legth is divisible by 4;
   *           beginning and end of a scanline is dword aligned
   */
  static void fast_imageblit(const struct fb_image *image, struct fb_info *p,
  				  void *dst1, u32 fgcolor, u32 bgcolor)
  {
  	u32 fgx = fgcolor, bgx = bgcolor, bpp = p->var.bits_per_pixel;
  	u32 ppw = 32/bpp, spitch = (image->width + 7)/8;
  	u32 bit_mask, end_mask, eorx, shift;
  	const char *s = image->data, *src;
  	u32 *dst;
  	const u32 *tab = NULL;
  	int i, j, k;
  
  	switch (bpp) {
  	case 8:
  		tab = fb_be_math(p) ? cfb_tab8_be : cfb_tab8_le;
  		break;
  	case 16:
  		tab = fb_be_math(p) ? cfb_tab16_be : cfb_tab16_le;
  		break;
  	case 32:
  	default:
  		tab = cfb_tab32;
  		break;
  	}
  
  	for (i = ppw-1; i--; ) {
  		fgx <<= bpp;
  		bgx <<= bpp;
  		fgx |= fgcolor;
  		bgx |= bgcolor;
  	}
  
  	bit_mask = (1 << ppw) - 1;
  	eorx = fgx ^ bgx;
  	k = image->width/ppw;
  
  	for (i = image->height; i--; ) {
  		dst = dst1;
  		shift = 8;
  		src = s;
  
  		for (j = k; j--; ) {
  			shift -= ppw;
  			end_mask = tab[(*src >> shift) & bit_mask];
  			*dst++ = (end_mask & eorx) ^ bgx;
  			if (!shift) {
  				shift = 8;
  				src++;
  			}
  		}
  		dst1 += p->fix.line_length;
  		s += spitch;
  	}
  }
  
  void sys_imageblit(struct fb_info *p, const struct fb_image *image)
  {
  	u32 fgcolor, bgcolor, start_index, bitstart, pitch_index = 0;
  	u32 bpl = sizeof(u32), bpp = p->var.bits_per_pixel;
  	u32 width = image->width;
  	u32 dx = image->dx, dy = image->dy;
  	void *dst1;
  
  	if (p->state != FBINFO_STATE_RUNNING)
  		return;
  
  	bitstart = (dy * p->fix.line_length * 8) + (dx * bpp);
  	start_index = bitstart & (32 - 1);
  	pitch_index = (p->fix.line_length & (bpl - 1)) * 8;
  
  	bitstart /= 8;
  	bitstart &= ~(bpl - 1);
  	dst1 = (void __force *)p->screen_base + bitstart;
  
  	if (p->fbops->fb_sync)
  		p->fbops->fb_sync(p);
  
  	if (image->depth == 1) {
  		if (p->fix.visual == FB_VISUAL_TRUECOLOR ||
  		    p->fix.visual == FB_VISUAL_DIRECTCOLOR) {
  			fgcolor = ((u32*)(p->pseudo_palette))[image->fg_color];
  			bgcolor = ((u32*)(p->pseudo_palette))[image->bg_color];
  		} else {
  			fgcolor = image->fg_color;
  			bgcolor = image->bg_color;
  		}
  
  		if (32 % bpp == 0 && !start_index && !pitch_index &&
  		    ((width & (32/bpp-1)) == 0) &&
  		    bpp >= 8 && bpp <= 32)
  			fast_imageblit(image, p, dst1, fgcolor, bgcolor);
  		else
  			slow_imageblit(image, p, dst1, fgcolor, bgcolor,
  					start_index, pitch_index);
  	} else
  		color_imageblit(image, p, dst1, start_index, pitch_index);
  }
  
  EXPORT_SYMBOL(sys_imageblit);
  
  MODULE_AUTHOR("Antonino Daplas <adaplas@pol.net>");
  MODULE_DESCRIPTION("1-bit/8-bit to 1-32 bit color expansion (sys-to-sys)");
  MODULE_LICENSE("GPL");