/*
 *  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,__FUNCTION__,## 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");