/*
 * Copyright (C) 2010 Juergen Beisert
 * Copyright (C) 2011 Alexey Galakhov
 *
 * This driver is based on a patch found in the web:
 * (C) Copyright 2006 by OpenMoko, Inc.
 * Author: Harald Welte <laforge at openmoko.org>
 *
 * 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 program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 *
 */

#include <common.h>
#include <init.h>
#include <fb.h>
#include <driver.h>
#include <malloc.h>
#include <errno.h>
#include <io.h>
#include <mach/s3c-generic.h>
#include <mach/s3c24xx-fb.h>

#define LCDCON1 0x00
# define PNRMODE(x) (((x) & 3) << 5)
# define BPPMODE(x) (((x) & 0xf) << 1)
# define SET_CLKVAL(x) (((x) & 0x3ff) << 8)
# define GET_CLKVAL(x) (((x) >> 8) & 0x3ff)
# define ENVID (1 << 0)

#define LCDCON2 0x04
# define SET_VBPD(x) (((x) & 0xff) << 24)
# define SET_LINEVAL(x) (((x) & 0x3ff) << 14)
# define SET_VFPD(x) (((x) & 0xff) << 6)
# define SET_VSPW(x) ((x) & 0x3f)

#define LCDCON3 0x08
# define SET_HBPD(x) (((x) & 0x7f) << 19)
# define SET_HOZVAL(x) (((x) & 0x7ff) << 8)
# define SET_HFPD(x) ((x) & 0xff)

#define LCDCON4 0x0c
# define SET_HSPW(x) ((x) & 0xff)

#define LCDCON5 0x10
# define BPP24BL (1 << 12)
# define FRM565 (1 << 11)
# define INV_CLK (1 << 10)
# define INV_HS (1 << 9)
# define INV_VS (1 << 8)
# define INV_DTA (1 << 7)
# define INV_DE (1 << 6)
# define INV_PWREN (1 << 5)
# define INV_LEND (1 << 4)
# define ENA_PWREN (1 << 3)
# define ENA_LEND (1 << 2)
# define BSWP (1 << 1)
# define HWSWP (1 << 0)

#define LCDSADDR1 0x14
# define SET_LCDBANK(x) (((x) & 0x1ff) << 21)
# define GET_LCDBANK(x) (((x) >> 21) & 0x1ff)
# define SET_LCDBASEU(x) ((x) & 0x1fffff)
# define GET_LCDBASEU(x) ((x) & 0x1fffff)

#define LCDSADDR2 0x18
# define SET_LCDBASEL(x) ((x) & 0x1fffff)
# define GET_LCDBASEL(x) ((x) & 0x1fffff)

#define LCDSADDR3 0x1c
# define SET_OFFSIZE(x) (((x) & 0x7ff) << 11)
# define GET_OFFSIZE(x) (((x) >> 11) & 0x7ff)
# define SET_PAGE_WIDTH(x) ((x) & 0x3ff)
# define GET_PAGE_WIDTH(x) ((x) & 0x3ff)

#define RED_LUT 0x20
#define GREEN_LUT 0x24
#define BLUE_LUT 0x28

#define DITHMODE 0x4c

#define TPAL 0x50

#define LCDINTPND 0x54
#define LCDSRCPND 0x58
#define LCDINTMSK 0x5c
# define FIWSEL (1 << 2)
# define INT_FrSyn (1 << 1)
# define INT_FiCnt (1 << 0)

#define TCONSEL 0x60

#define RED 0
#define GREEN 1
#define BLUE 2
#define TRANSP 3

struct s3cfb_info {
	void __iomem *base;
	unsigned memory_size;
	struct fb_info info;
	struct device_d *hw_dev;
	int passive_display;
	void (*enable)(int enable);
};

/* the RGB565 true colour mode */
static const struct fb_bitfield def_rgb565[] = {
	[RED] = {
		.offset = 11,
		.length = 5,
	},
	[GREEN] = {
		.offset = 5,
		.length = 6,
	},
	[BLUE] = {
		.offset = 0,
		.length = 5,
	},
	[TRANSP] = {	/* no support for transparency */
		.length = 0,
	}
};

/* the RGB888 true colour mode */
static const struct fb_bitfield def_rgb888[] = {
	[RED] = {
		.offset = 16,
		.length = 8,
	},
	[GREEN] = {
		.offset = 8,
		.length = 8,
	},
	[BLUE] = {
		.offset = 0,
		.length = 8,
	},
	[TRANSP] = {	/* no support for transparency */
		.length = 0,
	}
};

/**
 * @param fb_info Framebuffer information
 */
static void s3cfb_enable_controller(struct fb_info *fb_info)
{
	struct s3cfb_info *fbi = fb_info->priv;
	uint32_t con1;

	con1 = readl(fbi->base + LCDCON1);

	con1 |= ENVID;

	writel(con1, fbi->base + LCDCON1);

	if (fbi->enable)
		fbi->enable(1);
}

/**
 * @param fb_info Framebuffer information
 */
static void s3cfb_disable_controller(struct fb_info *fb_info)
{
	struct s3cfb_info *fbi = fb_info->priv;
	uint32_t con1;

	if (fbi->enable)
		fbi->enable(0);

	con1 = readl(fbi->base + LCDCON1);

	con1 &= ~ENVID;

	writel(con1, fbi->base + LCDCON1);
}

/**
 * Prepare the video hardware for a specified video mode
 * @param fb_info Framebuffer information
 * @return 0 on success
 */
static int s3cfb_activate_var(struct fb_info *fb_info)
{
	struct s3cfb_info *fbi = fb_info->priv;
	struct fb_videomode *mode = fb_info->mode;
	unsigned size, hclk, div;
	uint32_t con1, con2, con3, con4, con5 = 0;

	if (fbi->passive_display != 0) {
		dev_err(fbi->hw_dev, "Passive displays are currently not supported\n");
		return -EINVAL;
	}

	/*
	 * we need at least this amount of memory for the framebuffer
	 */
	size = mode->xres * mode->yres * (fb_info->bits_per_pixel >> 3);
	if (fbi->memory_size != size || fb_info->screen_base == NULL) {
		if (fb_info->screen_base)
			free(fb_info->screen_base);
		fbi->memory_size = 0;
		fb_info->screen_base = malloc(size);
		if (! fb_info->screen_base)
			return -ENOMEM;
		memset(fb_info->screen_base, 0, size);
		fbi->memory_size = size;
	}

	/* ensure video output is _off_ */
	writel(0x00000000, fbi->base + LCDCON1);

	hclk = s3c_get_hclk() / 1000U;	/* hclk in kHz */
	div = hclk / PICOS2KHZ(mode->pixclock);
	if (div < 3)
		div  = 3;
	/* pixel clock is: (hclk) / ((div + 1) * 2) */
	div += 1;
	div >>= 1;
	div -= 1;

	con1 = PNRMODE(3) | SET_CLKVAL(div);	/* PNRMODE=3 is TFT */

	switch (fb_info->bits_per_pixel) {
	case 16:
		con1 |= BPPMODE(12);
		con5 |= FRM565;
		con5 |= HWSWP;
		fb_info->red = def_rgb565[RED];
		fb_info->green = def_rgb565[GREEN];
		fb_info->blue = def_rgb565[BLUE];
		fb_info->transp =  def_rgb565[TRANSP];
		break;
	case 24:
		con1 |= BPPMODE(13);
		/* con5 |= BPP24BL;	*/ /* FIXME maybe needed, check alignment */
		fb_info->red = def_rgb888[RED];
		fb_info->green = def_rgb888[GREEN];
		fb_info->blue = def_rgb888[BLUE];
		fb_info->transp =  def_rgb888[TRANSP];
		break;
	default:
		dev_err(fbi->hw_dev, "Invalid bits per pixel value: %u\n", fb_info->bits_per_pixel);
		return -EINVAL;
	}

	/* 'normal' in register description means positive logic */
	if (!(mode->sync & FB_SYNC_HOR_HIGH_ACT))
		con5 |= INV_HS;
	if (!(mode->sync & FB_SYNC_VERT_HIGH_ACT))
		con5 |= INV_VS;
	if (!(mode->sync & FB_SYNC_DE_HIGH_ACT))
		con5 |= INV_DE;
	if (mode->sync & FB_SYNC_CLK_INVERT)
		con5 |= INV_CLK;	/* display should latch at the rising edge */
	if (mode->sync & FB_SYNC_DATA_INVERT)
		con5 |= INV_DTA;
	if (mode->sync & FB_SYNC_INVERT_PWREN)
		con5 |= INV_PWREN;
	if (mode->sync & FB_SYNC_INVERT_LEND)
		con5 |= INV_LEND;
	if (mode->sync & FB_SYNC_USE_PWREN)
		con5 |= ENA_PWREN;	/* FIXME should this be done conditionally/later? */
	if (mode->sync & FB_SYNC_USE_LEND)
		con5 |= ENA_LEND;
	if (mode->sync & FB_SYNC_SWAP_BYTES)
		con5 ^= BSWP;
	if (mode->sync & FB_SYNC_SWAP_HW)
		con5 ^= HWSWP;

	/* vertical timing */
	con2 = SET_VBPD(mode->upper_margin - 1) |
		SET_LINEVAL(mode->yres - 1) |
		SET_VFPD(mode->lower_margin - 1) |
		SET_VSPW(mode->vsync_len - 1);

	/* horizontal timing */
	con3 = SET_HBPD(mode->left_margin - 1) |
		SET_HOZVAL(mode->xres - 1) |
		SET_HFPD(mode->right_margin - 1);
	con4 = SET_HSPW(mode->hsync_len - 1);

	/* basic timing setup */
	writel(con1, fbi->base + LCDCON1);
	dev_dbg(fbi->hw_dev, "writing %08X into %p (con1)\n", con1, fbi->base + LCDCON1);
	writel(con2, fbi->base + LCDCON2);
	dev_dbg(fbi->hw_dev, "writing %08X into %p (con2)\n", con2, fbi->base + LCDCON2);
	writel(con3, fbi->base + LCDCON3);
	dev_dbg(fbi->hw_dev, "writing %08X into %p (con3)\n", con3, fbi->base + LCDCON3);
	writel(con4, fbi->base + LCDCON4);
	dev_dbg(fbi->hw_dev, "writing %08X into %p (con4)\n", con4, fbi->base + LCDCON4);
	writel(con5, fbi->base + LCDCON5);
	dev_dbg(fbi->hw_dev, "writing %08X into %p (con5)\n", con5, fbi->base + LCDCON5);

	dev_dbg(fbi->hw_dev, "setting up the fb baseadress to %p\n", fb_info->screen_base);

	/* framebuffer memory setup */
	writel((unsigned)fb_info->screen_base >> 1, fbi->base + LCDSADDR1);
	size = mode->xres * (fb_info->bits_per_pixel >> 3) * (mode->yres);
	writel(SET_LCDBASEL(((unsigned)fb_info->screen_base + size) >> 1), fbi->base + LCDSADDR2);
	writel(SET_OFFSIZE(0) |
		SET_PAGE_WIDTH((mode->xres * fb_info->bits_per_pixel) >> 4),
		fbi->base + LCDSADDR3);
	writel(FIWSEL | INT_FrSyn | INT_FiCnt, fbi->base + LCDINTMSK);

	return 0;
}

/**
 * Print some information about the current hardware state
 * @param hw_dev S3C video device
 */
static void s3cfb_info(struct device_d *hw_dev)
{
	uint32_t con1, addr1, addr2, addr3;
	struct s3cfb_info *fbi = hw_dev->priv;

	con1 = readl(fbi->base + LCDCON1);
	addr1 = readl(fbi->base + LCDSADDR1);
	addr2 = readl(fbi->base + LCDSADDR2);
	addr3 = readl(fbi->base + LCDSADDR3);

	printf(" Video hardware info:\n");
	printf("  Video clock is running at %u Hz\n", s3c_get_hclk() / ((GET_CLKVAL(con1) + 1) * 2));
	printf("  Video memory bank starts at 0x%08X\n", GET_LCDBANK(addr1) << 22);
	printf("  Video memory bank offset: 0x%08X\n", GET_LCDBASEU(addr1));
	printf("  Video memory end: 0x%08X\n", GET_LCDBASEU(addr2));
	printf("  Virtual screen offset size: %u half words\n", GET_OFFSIZE(addr3));
	printf("  Virtual screen page width: %u half words\n", GET_PAGE_WIDTH(addr3));
}

/*
 * There is only one video hardware instance available.
 * It makes no sense to dynamically allocate this data
 */
static struct fb_ops s3cfb_ops = {
	.fb_activate_var = s3cfb_activate_var,
	.fb_enable = s3cfb_enable_controller,
	.fb_disable = s3cfb_disable_controller,
};

static struct s3cfb_info fbi = {
	.info = {
		.fbops = &s3cfb_ops,
	},
};

static int s3cfb_probe(struct device_d *hw_dev)
{
	struct s3c_fb_platform_data *pdata = hw_dev->platform_data;
	int ret;

	if (! pdata)
		return -ENODEV;

	fbi.base = dev_request_mem_region(hw_dev, 0);
	writel(0, fbi.base + LCDCON1);
	writel(0, fbi.base + LCDCON5); /* FIXME not 0 for some displays */

	/* just init */
	fbi.info.priv = &fbi;

	/* add runtime hardware info */
	fbi.hw_dev = hw_dev;
	hw_dev->priv = &fbi;

	/* add runtime video info */
	fbi.info.modes.modes = pdata->mode_list;
	fbi.info.modes.num_modes = pdata->mode_cnt;
	fbi.info.mode = &fbi.info.modes.modes[0];
	fbi.info.xres = fbi.info.mode->xres;
	fbi.info.yres = fbi.info.mode->yres;
	if (pdata->bits_per_pixel)
		fbi.info.bits_per_pixel = pdata->bits_per_pixel;
	else
		fbi.info.bits_per_pixel = 16;
	fbi.passive_display = pdata->passive_display;
	fbi.enable = pdata->enable;

	if (IS_ENABLED(CONFIG_DRIVER_VIDEO_S3C_VERBOSE))
		hw_dev->info = s3cfb_info;

	ret = register_framebuffer(&fbi.info);
	if (ret != 0) {
		dev_err(hw_dev, "Failed to register framebuffer\n");
		return -EINVAL;
	}

	return 0;
}

static struct driver_d s3cfb_driver = {
	.name	= "s3c_fb",
	.probe	= s3cfb_probe,
};
device_platform_driver(s3cfb_driver);

/**
 * The S3C244x LCD controller supports passive (CSTN/STN) and active (TFT) LC displays
 *
 * The driver itself currently supports only active TFT LC displays in the follwing manner:
 *
 *  * True colours
 *    - 16 bpp
 *    - 24 bpp (untested)
 */
