/*
 *  Generic BitBLT function for frame buffer with packed pixels of any depth.
 *
 *      Copyright (C)  June 1999 James Simmons
 *
 *  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 function copys a image from system memory to video memory. The
 *  image can be a bitmap where each 0 represents the background color and
 *  each 1 represents the foreground color. Great for font handling. It can
 *  also be a color image. This is determined by image_depth. The color image
 *  must be laid out exactly in the same format as the framebuffer. Yes I know
 *  their are cards with hardware that coverts images of various depths to the
 *  framebuffer depth. But not every card has this. All images must be rounded
 *  up to the nearest byte. For example a bitmap 12 bits wide must be two 
 *  bytes width. 
 *
 *  Tony: 
 *  Incorporate mask tables similar to fbcon-cfb*.c in 2.4 API.  This speeds 
 *  up the code significantly.
 *  
 *  Code for depths not multiples of BITS_PER_LONG is still kludgy, which is
 *  still processed a bit at a time.   
 *
 *  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.
 */
#include <linux/module.h>
#include <linux/string.h>
#include <linux/fb.h>
#include <asm/types.h>
#include "fb_draw.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
};

#define FB_WRITEL fb_writel
#define FB_READL  fb_readl

static inline void color_imageblit(const struct fb_image *image, 
                                   struct fb_info *p, u8 __iomem *dst1, 
                                   u32 start_index,
                                   u32 pitch_index)
{
        /* Draw the penguin */
        u32 __iomem *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;
        u32 bswapmask = fb_compute_bswapmask(p);

        dst2 = (u32 __iomem *) dst1;
        for (i = image->height; i--; ) {
                n = image->width;
                dst = (u32 __iomem *) dst1;
                shift = 0;
                val = 0;
                
                if (start_index) {
                        u32 start_mask = ~fb_shifted_pixels_mask_u32(p,
                                                start_index, bswapmask);
                        val = FB_READL(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 ^ bswapmask);
                        if (shift >= null_bits) {
                                FB_WRITEL(val, dst++);
        
                                val = (shift == null_bits) ? 0 : 
                                        FB_SHIFT_LOW(p, color, 32 - shift);
                        }
                        shift += bpp;
                        shift &= (32 - 1);
                        src++;
                }
                if (shift) {
                        u32 end_mask = fb_shifted_pixels_mask_u32(p, shift,
                                                bswapmask);

                        FB_WRITEL((FB_READL(dst) & end_mask) | val, dst);
                }
                dst1 += p->fix.line_length;
                if (pitch_index) {
                        dst2 += p->fix.line_length;
                        dst1 = (u8 __iomem *)((long __force)dst2 & ~(sizeof(u32) - 1));

                        start_index += pitch_index;
                        start_index &= 32 - 1;
                }
        }
}

static inline void slow_imageblit(const struct fb_image *image, struct fb_info *p, 
                                  u8 __iomem *dst1, u32 fgcolor,
                                  u32 bgcolor, 
                                  u32 start_index,
                                  u32 pitch_index)
{
        u32 shift, color = 0, bpp = p->var.bits_per_pixel;
        u32 __iomem *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;
        u32 bswapmask = fb_compute_bswapmask(p);

        dst2 = (u32 __iomem *) 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 = (u32 __iomem *) dst1;
                s = src;

                /* write leading bits */
                if (start_index) {
                        u32 start_mask = ~fb_shifted_pixels_mask_u32(p,
                                                start_index, bswapmask);
                        val = FB_READL(dst) & start_mask;
                        shift = start_index;
                }

                while (j--) {
                        l--;
                        color = (*s & (1 << l)) ? fgcolor : bgcolor;
                        val |= FB_SHIFT_HIGH(p, color, shift ^ bswapmask);
                        
                        /* Did the bitshift spill bits to the next long? */
                        if (shift >= null_bits) {
                                FB_WRITEL(val, dst++);
                                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_shifted_pixels_mask_u32(p, shift,
                                                bswapmask);

                        FB_WRITEL((FB_READL(dst) & end_mask) | val, dst);
                }
                
                dst1 += pitch;
                src += spitch;  
                if (pitch_index) {
                        dst2 += pitch;
                        dst1 = (u8 __iomem *)((long __force)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 inline void fast_imageblit(const struct fb_image *image, struct fb_info *p, 
                                  u8 __iomem *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 __iomem *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 = (u32 __iomem *) dst1, shift = 8; src = s;
                
                for (j = k; j--; ) {
                        shift -= ppw;
                        end_mask = tab[(*src >> shift) & bit_mask];
                        FB_WRITEL((end_mask & eorx)^bgx, dst++);
                        if (!shift) { shift = 8; src++; }               
                }
                dst1 += p->fix.line_length;
                s += spitch;
        }
}       
        
void cfb_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;
        u8 __iomem *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 = 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(cfb_imageblit);

MODULE_AUTHOR("James Simmons <jsimmons@users.sf.net>");
MODULE_DESCRIPTION("Generic software accelerated imaging drawing");
MODULE_LICENSE("GPL");