/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (c) 2011 by Amaury Pouly
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/
#include <sys/types.h> /* off_t */
#include <string.h>
#include "cpu.h"
#include "system.h"
#include "backlight-target.h"
#include "lcd.h"
#include "lcdif-imx233.h"
#include "clkctrl-imx233.h"
#include "pinctrl-imx233.h"
#include "logf.h"

#ifdef HAVE_LCD_ENABLE
static bool lcd_on;
#endif

static void setup_lcdif(void)
{
    imx233_lcdif_init();
    imx233_lcdif_set_lcd_databus_width(18);
    imx233_lcdif_set_word_length(18);
    imx233_lcdif_set_timings(2, 2, 3, 3);
    imx233_lcdif_enable_underflow_recover(true);
    imx233_lcdif_enable(true);
    imx233_lcdif_setup_system_pins(18);
    imx233_lcdif_enable_bus_master(true);
}

static inline uint32_t encode_16_to_18(uint32_t a)
{
    return ((a & 0xff) << 1) | (((a >> 8) & 0xff) << 10);
}

static inline uint32_t decode_18_to_16(uint32_t a)
{
    return ((a >> 1) & 0xff) | ((a >> 2) & 0xff00);
}

static void setup_lcdif_clock(void)
{
    /* the LCD seems to work at 24Mhz, so use the xtal clock with no divider */
    imx233_clkctrl_enable(CLK_PIX, false);
    imx233_clkctrl_set_div(CLK_PIX, 1);
    imx233_clkctrl_set_bypass(CLK_PIX, true); /* use XTAL */
    imx233_clkctrl_enable(CLK_PIX, true);
}

static void lcd_write_reg(uint32_t reg, uint32_t data)
{
    uint32_t old_reg = reg;
    /* get back to 18-bit word length */
    imx233_lcdif_set_word_length(18);
    reg = encode_16_to_18(reg);
    data = encode_16_to_18(data);
    
    imx233_lcdif_pio_send(false, 1, &reg);
    if(old_reg != 0 && old_reg != 0x202)
        imx233_lcdif_pio_send(true, 1, &data);
}

#define REG_MDELAY  0xffffffff
struct lcd_sequence_entry_t
{
    uint32_t reg, data;
};

static void lcd_send_sequence(struct lcd_sequence_entry_t *seq, unsigned count)
{
    for(;count-- > 0; seq++)
    {
        if(seq->reg == REG_MDELAY)
            mdelay(seq->data);
        else
            lcd_write_reg(seq->reg, seq->data);
    }
}

#define _begin_seq() static struct lcd_sequence_entry_t __seq[] = {
#define _mdelay(a) {REG_MDELAY, a},
#define _lcd_write_reg(a, b) {a, b},
#define _end_seq() }; lcd_send_sequence(__seq, sizeof(__seq) / sizeof(__seq[0]));

static void lcd_init_seq(void)
{
    _begin_seq()
    _lcd_write_reg(0, 0)
    _lcd_write_reg(0, 0)
    _lcd_write_reg(0, 0)
    _lcd_write_reg(0, 0)
    _mdelay(100)
    _lcd_write_reg(8, 0x808)
    _lcd_write_reg(0x10, 0x10)
    _lcd_write_reg(0x400, 0x6200)
    _lcd_write_reg(0x300, 0xc0a)
    _lcd_write_reg(0x301, 0x4c11)
    _lcd_write_reg(0x302, 0x906)
    _lcd_write_reg(0x303, 0x1417)
    _lcd_write_reg(0x304, 0x3333)
    _lcd_write_reg(0x305, 0x150d)
    _lcd_write_reg(0x306, 0x740a)
    _lcd_write_reg(0x307, 0x100c)
    _lcd_write_reg(0x308, 0x60c)
    _lcd_write_reg(0x309, 0)
    _lcd_write_reg(0x100, 0x730)
    _lcd_write_reg(0x101, 0x237)
    _lcd_write_reg(0x103, 0x2b00)
    _lcd_write_reg(0x280, 0x4000)
    _lcd_write_reg(0x102, 0x81b0)
    _mdelay(400)
    _lcd_write_reg(1, 0x100)
    _lcd_write_reg(2, 0x100)
    _lcd_write_reg(3, 0x5028)
    _lcd_write_reg(9, 1)
    _lcd_write_reg(0xc, 0)
    _lcd_write_reg(0x11, 0x202)
    _lcd_write_reg(0x12, 0x101)
    _lcd_write_reg(0x13, 1)
    _lcd_write_reg(0x90, 0x8000)
    _lcd_write_reg(0x210, 0)
    _lcd_write_reg(0x211, 0xef)
    _lcd_write_reg(0x212, 0)
    _lcd_write_reg(0x213, 0x18f)
    _lcd_write_reg(0x200, 0)
    _lcd_write_reg(0x201, 0)
    _lcd_write_reg(0x401, 1)
    _lcd_write_reg(0x404, 0)
    _mdelay(400)
    _lcd_write_reg(7, 0x100)
    _mdelay(400)
    _lcd_write_reg(3, 0x1030)
    _end_seq()
}

void lcd_init_device(void)
{
    setup_lcdif();
    setup_lcdif_clock();

    // reset device
    imx233_lcdif_reset_lcd(true);
    mdelay(50);
    imx233_lcdif_reset_lcd(false);
    mdelay(10);
    imx233_lcdif_reset_lcd(true);

    lcd_init_seq();
#ifdef HAVE_LCD_ENABLE
    lcd_on = true;
#endif
}

#ifdef HAVE_LCD_ENABLE
bool lcd_active(void)
{
    return lcd_on;
}

static void lcd_enable_seq(bool enable)
{
    if(!enable)
    {
        _begin_seq()
        _end_seq()
    }
    else
    {
        _begin_seq()
        _end_seq()
    }
}

void lcd_enable(bool enable)
{
    if(lcd_on == enable)
        return;

    lcd_on = enable;
    
    lcd_enable_seq(enable);
    if(enable)
        send_event(LCD_EVENT_ACTIVATION, NULL);
}
#endif

void lcd_update(void)
{
    lcd_update_rect(0, 0, LCD_WIDTH, LCD_HEIGHT);
}

void lcd_update_rect(int x, int y, int w, int h)
{
#ifdef HAVE_LCD_ENABLE
    if(!lcd_on)
        return;
#endif
    /* make sure the rectangle is included in the screen */
    x = MIN(x, LCD_WIDTH);
    y = MIN(y, LCD_HEIGHT);
    w = MIN(w, LCD_WIDTH - x);
    h = MIN(h, LCD_HEIGHT - y);
    
    imx233_lcdif_wait_ready();
    lcd_write_reg(0x210, x);
    lcd_write_reg(0x211, x + w - 1);
    lcd_write_reg(0x212, y);
    lcd_write_reg(0x213, y + h - 1);
    lcd_write_reg(0x200, 0);
    lcd_write_reg(0x201, 0);
    lcd_write_reg(0x202, 0);
    imx233_lcdif_wait_ready();
    imx233_lcdif_set_word_length(16);
    imx233_lcdif_set_byte_packing_format(0xf); /* two pixels per 32-bit word */

    /* there are two cases here:
     * - either width = LCD_WIDTH and we can directly memcopy a part of lcd_framebuffer to FRAME
     *   and send it
     * - either width != LCD_WIDTH and we have to build a contiguous copy of the rectangular area
     *   into FRAME before sending it (which is slower and doesn't use the hardware)
     * In all cases, FRAME just acts as a temporary buffer.
     * NOTE It's more interesting to do a copy to FRAME in all cases since in system mode
     * the clock runs at 24MHz which provides barely 10MB/s bandwidth compared to >100MB/s
     * for memcopy operations
     */
    if(w == LCD_WIDTH)
    {
        memcpy((void *)FRAME, FBADDR(x,y), w * h * sizeof(fb_data));
    }
    else
    {
        for(int i = 0; i < h; i++)
            memcpy((fb_data *)FRAME + i * w, FBADDR(x,y + i), w * sizeof(fb_data));
    }
    /* WARNING The LCDIF has a limitation on the vertical count ! In 16-bit packed mode
     * (which we used, ie 16-bit per pixel, 2 pixels per 32-bit words), the v_count
     * field must be a multiple of 2. Furthermore, it seems the lcd controller doesn't
     * really like when both w and h are even, probably because the writes to the GRAM
     * are done on several words and the controller requires dummy writes.
     * The workaround is to always make sure that we send a number of pixels which is
     * a multiple of 4 so that both the lcdif and the controller are happy. If any
     * of w or h is odd, we will send a copy of the first pixels as dummy writes. We will
     * send at most 3 bytes. We then send (w * h + 3) / 4 x 4 bytes.
     */
    if(w % 2 == 1 || h % 2 == 1)
    {
        /* copy three pixel after the last one */
        for(int i = 0; i < 3; i++)
            *((fb_data *)FRAME + w * h + i) = *((fb_data *)FRAME + i);
        /* WARNING we need to update w and h to reflect the pixel count BUT it
         * has no relation to w * h (it can even be 2 * prime). Hopefully, w <= 240 and
         * h <= 320 so w * h <= 76800 and (w * h + 3) / 4 <= 38400 which fits into
         * a 16-bit integer (horizontal count). */
        h = (w * h + 3) / 4;
        w = 4;
    }
    imx233_lcdif_dma_send((void *)FRAME_PHYS_ADDR, w, h);
}