/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * LCD driver for iPod Video
 * 
 * Based on code from the ipodlinux project - http://ipodlinux.org/
 * Adapted for Rockbox in December 2005
 *
 * Original file: linux/arch/armnommu/mach-ipod/fb.c
 *
 * Copyright (c) 2003-2005 Bernard Leach (leachbj@bouncycastle.org)
 *
 * All files in this archive are subject to the GNU General Public License.
 * See the file COPYING in the source tree root for full license agreement.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/
#include "config.h"
#include "cpu.h"
#include "lcd.h"
#include "kernel.h"
#include "system.h"

/*** hardware configuration ***/

void lcd_set_contrast(int val)
{
  /* TODO: Implement lcd_set_contrast() */
  (void)val;
}

void lcd_set_invert_display(bool yesno)
{
  /* TODO: Implement lcd_set_invert_display() */
  (void)yesno;
}

/* turn the display upside down (call lcd_update() afterwards) */
void lcd_set_flip(bool yesno)
{
  /* TODO: Implement lcd_set_flip() */
  (void)yesno;
}

/* LCD init */
void lcd_init_device(void)
{  
    /* iPodLinux doesn't appear have any LCD init code for the Video */
}

/*** update functions ***/

/* Performance function that works with an external buffer
   note that by and bheight are in 4-pixel units! */
void lcd_blit(const fb_data* data, int x, int by, int width,
              int bheight, int stride)
{
    /* TODO: Implement lcd_blit() */
    (void)data;
    (void)x;
    (void)by;
    (void)width;
    (void)bheight;
    (void)stride;
}

static inline void lcd_bcm_write32(unsigned address, unsigned value)
{
    /* write out destination address as two 16bit values */
    outw(address, 0x30010000);
    outw((address >> 16), 0x30010000);

    /* wait for it to be write ready */
    while ((inw(0x30030000) & 0x2) == 0);

    /* write out the value low 16, high 16 */
    outw(value, 0x30000000);
    outw((value >> 16), 0x30000000);
}

static void lcd_bcm_setup_rect(unsigned cmd,
                               unsigned start_horiz, 
                               unsigned start_vert, 
                               unsigned max_horiz,
                               unsigned max_vert, 
                               unsigned count)
{
    lcd_bcm_write32(0x1F8, 0xFFFA0005);
    lcd_bcm_write32(0xE0000, cmd);
    lcd_bcm_write32(0xE0004, start_horiz);
    lcd_bcm_write32(0xE0008, start_vert);
    lcd_bcm_write32(0xE000C, max_horiz);
    lcd_bcm_write32(0xE0010, max_vert);
    lcd_bcm_write32(0xE0014, count);
    lcd_bcm_write32(0xE0018, count);
    lcd_bcm_write32(0xE001C, 0);
}

static unsigned lcd_bcm_read32(unsigned address) {
    while ((inw(0x30020000) & 1) == 0);

    /* write out destination address as two 16bit values */
    outw(address, 0x30020000);
    outw((address >> 16), 0x30020000);

    /* wait for it to be read ready */
    while ((inw(0x30030000) & 0x10) == 0);

    /* read the value */
    return inw(0x30000000) | inw(0x30000000) << 16;
}

static int finishup_needed = 0;

/* Update a fraction of the display. */
void lcd_update_rect(int x, int y, int width, int height) ICODE_ATTR;
void lcd_update_rect(int x, int y, int width, int height)
{
    {
        int endy = x + width;
        /* Ensure x and width are both even - so we can read 32-bit aligned 
           data from lcd_framebuffer */
        x &= ~1;
        width &= ~1;
        if (x + width < endy) {
            width += 2;
        }
    }

    if (finishup_needed) {
        unsigned int data;
        /* Bottom-half of original lcd_bcm_finishup() function */
        do {
            /* This function takes about 14ms to execute - so we yield() */
            yield();
            data = lcd_bcm_read32(0x1F8);
        } while (data == 0xFFFA0005 || data == 0xFFFF);
    }

    lcd_bcm_read32(0x1FC);

    {
        int rect1, rect2, rect3, rect4;
        int count = (width * height) << 1;
        /* calculate the drawing region */
        rect1 = x;                         /* start horiz */
        rect2 = y;                         /* start vert */
        rect3 = (x + width) - 1;           /* max horiz */
        rect4 = (y + height) - 1;          /* max vert */

        /* setup the drawing region */
        lcd_bcm_setup_rect(0x34, rect1, rect2, rect3, rect4, count);
    }

    /* write out destination address as two 16bit values */
    outw((0xE0020 & 0xffff), 0x30010000);
    outw((0xE0020 >> 16), 0x30010000);

    /* wait for it to be write ready */
    while ((inw(0x30030000) & 0x2) == 0);

    {
        unsigned short *src = (unsigned short*)&lcd_framebuffer[y][x];
        unsigned short *end = &src[LCD_WIDTH * height];
        int line_rem = (LCD_WIDTH - width);
        while (src < end) {
            /* Duff's Device to unroll loop */
            register int count = width ;
            register int n=( count + 7 ) / 8;
            switch( count % 8 ) {
                case 0: do{ outw(*(src++), 0x30000000);
                case 7:     outw(*(src++), 0x30000000);
                case 6:     outw(*(src++), 0x30000000);
                case 5:     outw(*(src++), 0x30000000);
                case 4:     outw(*(src++), 0x30000000);
                case 3:     outw(*(src++), 0x30000000);
                case 2:     outw(*(src++), 0x30000000);
                case 1:     outw(*(src++), 0x30000000);
              } while(--n>0);
            }
            src += line_rem;
        }
    }

    /* Top-half of original lcd_bcm_finishup() function */
    outw(0x31, 0x30030000); 

    lcd_bcm_read32(0x1FC);

    finishup_needed = 1;
}

/* Update the display.
   This must be called after all other LCD functions that change the display. */
void lcd_update(void)
{
    lcd_update_rect(0, 0, LCD_WIDTH, LCD_HEIGHT);
}

#define CSUB_X 2
#define CSUB_Y 2

#define RYFAC (31*257)
#define GYFAC (31*257)
#define BYFAC (31*257)
#define RVFAC 11170     /* 31 * 257 *  1.402    */
#define GVFAC (-5690)  /* 31 * 257 * -0.714136 */
#define GUFAC (-2742)   /* 31 * 257 * -0.344136 */
#define BUFAC 14118     /* 31 * 257 *  1.772    */

#define ROUNDOFFS (127*257)
#define ROUNDOFFSG (63*257)

/* Performance function to blit a YUV bitmap directly to the LCD */
void lcd_yuv_blit(unsigned char * const src[3],
                  int src_x, int src_y, int stride,
                  int x, int y, int width, int height)
{
    int ymax;

    width = (width + 1) & ~1;

    if (finishup_needed) {
        unsigned int data;
        /* Bottom-half of original lcd_bcm_finishup() function */
        data = lcd_bcm_read32(0x1F8);
        while (data == 0xFFFA0005 || data == 0xFFFF) {
            /* This loop can wait for up to 14ms - so we yield() */
            yield();
            data = lcd_bcm_read32(0x1F8);
        } 
    }

    lcd_bcm_read32(0x1FC);

    {
        int rect1, rect2, rect3, rect4;
        int count = (width * height) << 1;
        /* calculate the drawing region */
        rect1 = x;                         /* start horiz */
        rect2 = y;                         /* start vert */
        rect3 = (x + width) - 1;           /* max horiz */
        rect4 = (y + height) - 1;          /* max vert */

        /* setup the drawing region */
        lcd_bcm_setup_rect(0x34, rect1, rect2, rect3, rect4, count);
    }

    /* write out destination address as two 16bit values */
    outw((0xE0020 & 0xffff), 0x30010000);
    outw((0xE0020 >> 16), 0x30010000);

    /* wait for it to be write ready */
    while ((inw(0x30030000) & 0x2) == 0);

    ymax = y + height - 1 ;

    const int stride_div_csub_x = stride/CSUB_X;

    for (; y <= ymax ; y++)
    {
        /* upsampling, YUV->RGB conversion and reduction to RGB565 in one go */
        const unsigned char *ysrc = src[0] + stride * src_y + src_x;

        const int uvoffset = stride_div_csub_x * (src_y/CSUB_Y) +
                             (src_x/CSUB_X);

        const unsigned char *usrc = src[1] + uvoffset;
        const unsigned char *vsrc = src[2] + uvoffset;
        const unsigned char *row_end = ysrc + width;

        int y, u, v;
        int red1, green1, blue1;
        int red2, green2, blue2;
        unsigned rbits, gbits, bbits;

        int rc, gc, bc;

        do
        {
            u = *usrc++ - 128;
            v = *vsrc++ - 128;
            rc = RVFAC * v + ROUNDOFFS;
            gc = GVFAC * v + GUFAC * u + ROUNDOFFSG;
            bc = BUFAC * u + ROUNDOFFS;

            /* Pixel 1 */
            y = *ysrc++;

            red1   = RYFAC * y + rc;
            green1 = GYFAC * y + gc;
            blue1  = BYFAC * y + bc;

            /* Pixel 2 */
            y = *ysrc++;
            red2   = RYFAC * y + rc;
            green2 = GYFAC * y + gc;
            blue2  = BYFAC * y + bc;

            /* Since out of bounds errors are relatively rare, we check two
               pixels at once to see if any components are out of bounds, and
               then fix whichever is broken. This works due to high values and
               negative values both becoming larger than the cutoff when
               casted to unsigned.  And ORing them together checks all of them
               simultaneously.  */
            if (((unsigned)(red1 | green1 | blue1 |
                     red2 | green2 | blue2)) > (RYFAC*255+ROUNDOFFS)) {
                if (((unsigned)(red1 | green1 | blue1)) > 
                    (RYFAC*255+ROUNDOFFS)) {
                    if ((unsigned)red1 > (RYFAC*255+ROUNDOFFS))
                    {
                        if (red1 < 0)
                            red1 = 0;
                        else
                            red1 = (RYFAC*255+ROUNDOFFS);
                    }
                    if ((unsigned)green1 > (GYFAC*255+ROUNDOFFSG))
                    {
                        if (green1 < 0)
                            green1 = 0;
                        else
                            green1 = (GYFAC*255+ROUNDOFFSG);
                    }
                    if ((unsigned)blue1 > (BYFAC*255+ROUNDOFFS))
                    {
                        if (blue1 < 0)
                            blue1 = 0;
                        else
                            blue1 = (BYFAC*255+ROUNDOFFS);
                    }
                }

                if (((unsigned)(red2 | green2 | blue2)) > 
                    (RYFAC*255+ROUNDOFFS)) {
                    if ((unsigned)red2 > (RYFAC*255+ROUNDOFFS))
                    {
                        if (red2 < 0)
                            red2 = 0;
                        else
                            red2 = (RYFAC*255+ROUNDOFFS);
                    }
                    if ((unsigned)green2 > (GYFAC*255+ROUNDOFFSG))
                    {
                        if (green2 < 0)
                            green2 = 0;
                        else
                            green2 = (GYFAC*255+ROUNDOFFSG);
                    }
                    if ((unsigned)blue2 > (BYFAC*255+ROUNDOFFS))
                    {
                        if (blue2 < 0)
                            blue2 = 0;
                        else
                            blue2 = (BYFAC*255+ROUNDOFFS);
                    }
                }
            }
                
            rbits = red1 >> 16 ;
            gbits = green1 >> 15 ;
            bbits = blue1 >> 16 ;

            outw((rbits << 11) | (gbits << 5) | bbits, 0x30000000);

            rbits = red2 >> 16 ;
            gbits = green2 >> 15 ;
            bbits = blue2 >> 16 ;
            outw((rbits << 11) | (gbits << 5) | bbits, 0x30000000);
        }
        while (ysrc < row_end);

        src_y++;
    }

    /* Top-half of original lcd_bcm_finishup() function */
    outw(0x31, 0x30030000); 

    lcd_bcm_read32(0x1FC);

    finishup_needed = 1;
}
