/*
   *  Cobalt/SEAD3 LCD frame buffer driver.
   *
   *  Copyright (C) 2008  Yoichi Yuasa <yuasa@linux-mips.org>
   *  Copyright (C) 2012  MIPS Technologies, Inc.
   *
   *  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.
   *
   *  You should have received a copy of the GNU General Public License
   *  along with this program; if not, write to the Free Software
   *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  #include <linux/delay.h>
  #include <linux/fb.h>
  #include <linux/init.h>
  #include <linux/io.h>
  #include <linux/ioport.h>
  #include <linux/uaccess.h>
  #include <linux/platform_device.h>
  #include <linux/module.h>
  
  /*
   * Cursor position address
   * \X  0    1    2  ...  14   15
   * Y+----+----+----+---+----+----+
   * 0|0x00|0x01|0x02|...|0x0e|0x0f|
   *  +----+----+----+---+----+----+
   * 1|0x40|0x41|0x42|...|0x4e|0x4f|
   *  +----+----+----+---+----+----+
   */
  #define LCD_DATA_REG_OFFSET	0x10
  #define LCD_XRES_MAX		16
  #define LCD_YRES_MAX		2
  #define LCD_CHARS_MAX		32
  
  #define LCD_CLEAR		0x01
  #define LCD_CURSOR_MOVE_HOME	0x02
  #define LCD_RESET		0x06
  #define LCD_OFF			0x08
  #define LCD_CURSOR_OFF		0x0c
  #define LCD_CURSOR_BLINK_OFF	0x0e
  #define LCD_CURSOR_ON		0x0f
  #define LCD_ON			LCD_CURSOR_ON
  #define LCD_CURSOR_MOVE_LEFT	0x10
  #define LCD_CURSOR_MOVE_RIGHT	0x14
  #define LCD_DISPLAY_LEFT	0x18
  #define LCD_DISPLAY_RIGHT	0x1c
  #define LCD_PRERESET		0x3f	/* execute 4 times continuously */
  #define LCD_BUSY		0x80
  
  #define LCD_GRAPHIC_MODE	0x40
  #define LCD_TEXT_MODE		0x80
  #define LCD_CUR_POS_MASK	0x7f
  
  #define LCD_CUR_POS(x)		((x) & LCD_CUR_POS_MASK)
  #define LCD_TEXT_POS(x)		((x) | LCD_TEXT_MODE)
  
  #ifdef CONFIG_MIPS_COBALT
  static inline void lcd_write_control(struct fb_info *info, u8 control)
  {
  	writel((u32)control << 24, info->screen_base);
  }
  
  static inline u8 lcd_read_control(struct fb_info *info)
  {
  	return readl(info->screen_base) >> 24;
  }
  
  static inline void lcd_write_data(struct fb_info *info, u8 data)
  {
  	writel((u32)data << 24, info->screen_base + LCD_DATA_REG_OFFSET);
  }
  
  static inline u8 lcd_read_data(struct fb_info *info)
  {
  	return readl(info->screen_base + LCD_DATA_REG_OFFSET) >> 24;
  }
  #else
  
  #define LCD_CTL			0x00
  #define LCD_DATA		0x08
  #define CPLD_STATUS		0x10
  #define CPLD_DATA		0x18
  
  static inline void cpld_wait(struct fb_info *info)
  {
  	do {
  	} while (readl(info->screen_base + CPLD_STATUS) & 1);
  }
  
  static inline void lcd_write_control(struct fb_info *info, u8 control)
  {
  	cpld_wait(info);
  	writel(control, info->screen_base + LCD_CTL);
  }
  
  static inline u8 lcd_read_control(struct fb_info *info)
  {
  	cpld_wait(info);
  	readl(info->screen_base + LCD_CTL);
  	cpld_wait(info);
  	return readl(info->screen_base + CPLD_DATA) & 0xff;
  }
  
  static inline void lcd_write_data(struct fb_info *info, u8 data)
  {
  	cpld_wait(info);
  	writel(data, info->screen_base + LCD_DATA);
  }
  
  static inline u8 lcd_read_data(struct fb_info *info)
  {
  	cpld_wait(info);
  	readl(info->screen_base + LCD_DATA);
  	cpld_wait(info);
  	return readl(info->screen_base + CPLD_DATA) & 0xff;
  }
  #endif
  
  static int lcd_busy_wait(struct fb_info *info)
  {
  	u8 val = 0;
  	int timeout = 10, retval = 0;
  
  	do {
  		val = lcd_read_control(info);
  		val &= LCD_BUSY;
  		if (val != LCD_BUSY)
  			break;
  
  		if (msleep_interruptible(1))
  			return -EINTR;
  
  		timeout--;
  	} while (timeout);
  
  	if (val == LCD_BUSY)
  		retval = -EBUSY;
  
  	return retval;
  }
  
  static void lcd_clear(struct fb_info *info)
  {
  	int i;
  
  	for (i = 0; i < 4; i++) {
  		udelay(150);
  
  		lcd_write_control(info, LCD_PRERESET);
  	}
  
  	udelay(150);
  
  	lcd_write_control(info, LCD_CLEAR);
  
  	udelay(150);
  
  	lcd_write_control(info, LCD_RESET);
  }
  
  static struct fb_fix_screeninfo cobalt_lcdfb_fix = {
  	.id		= "cobalt-lcd",
  	.type		= FB_TYPE_TEXT,
  	.type_aux	= FB_AUX_TEXT_MDA,
  	.visual		= FB_VISUAL_MONO01,
  	.line_length	= LCD_XRES_MAX,
  	.accel		= FB_ACCEL_NONE,
  };
  
  static ssize_t cobalt_lcdfb_read(struct fb_info *info, char __user *buf,
  				 size_t count, loff_t *ppos)
  {
  	char src[LCD_CHARS_MAX];
  	unsigned long pos;
  	int len, retval = 0;
  
  	pos = *ppos;
  	if (pos >= LCD_CHARS_MAX || count == 0)
  		return 0;
  
  	if (count > LCD_CHARS_MAX)
  		count = LCD_CHARS_MAX;
  
  	if (pos + count > LCD_CHARS_MAX)
  		count = LCD_CHARS_MAX - pos;
  
  	for (len = 0; len < count; len++) {
  		retval = lcd_busy_wait(info);
  		if (retval < 0)
  			break;
  
  		lcd_write_control(info, LCD_TEXT_POS(pos));
  
  		retval = lcd_busy_wait(info);
  		if (retval < 0)
  			break;
  
  		src[len] = lcd_read_data(info);
  		if (pos == 0x0f)
  			pos = 0x40;
  		else
  			pos++;
  	}
  
  	if (retval < 0 && signal_pending(current))
  		return -ERESTARTSYS;
  
  	if (copy_to_user(buf, src, len))
  		return -EFAULT;
  
  	*ppos += len;
  
  	return len;
  }
  
  static ssize_t cobalt_lcdfb_write(struct fb_info *info, const char __user *buf,
  				  size_t count, loff_t *ppos)
  {
  	char dst[LCD_CHARS_MAX];
  	unsigned long pos;
  	int len, retval = 0;
  
  	pos = *ppos;
  	if (pos >= LCD_CHARS_MAX || count == 0)
  		return 0;
  
  	if (count > LCD_CHARS_MAX)
  		count = LCD_CHARS_MAX;
  
  	if (pos + count > LCD_CHARS_MAX)
  		count = LCD_CHARS_MAX - pos;
  
  	if (copy_from_user(dst, buf, count))
  		return -EFAULT;
  
  	for (len = 0; len < count; len++) {
  		retval = lcd_busy_wait(info);
  		if (retval < 0)
  			break;
  
  		lcd_write_control(info, LCD_TEXT_POS(pos));
  
  		retval = lcd_busy_wait(info);
  		if (retval < 0)
  			break;
  
  		lcd_write_data(info, dst[len]);
  		if (pos == 0x0f)
  			pos = 0x40;
  		else
  			pos++;
  	}
  
  	if (retval < 0 && signal_pending(current))
  		return -ERESTARTSYS;
  
  	*ppos += len;
  
  	return len;
  }
  
  static int cobalt_lcdfb_blank(int blank_mode, struct fb_info *info)
  {
  	int retval;
  
  	retval = lcd_busy_wait(info);
  	if (retval < 0)
  		return retval;
  
  	switch (blank_mode) {
  	case FB_BLANK_UNBLANK:
  		lcd_write_control(info, LCD_ON);
  		break;
  	default:
  		lcd_write_control(info, LCD_OFF);
  		break;
  	}
  
  	return 0;
  }
  
  static int cobalt_lcdfb_cursor(struct fb_info *info, struct fb_cursor *cursor)
  {
  	u32 x, y;
  	int retval;
  
  	switch (cursor->set) {
  	case FB_CUR_SETPOS:
  		x = cursor->image.dx;
  		y = cursor->image.dy;
  		if (x >= LCD_XRES_MAX || y >= LCD_YRES_MAX)
  			return -EINVAL;
  
  		retval = lcd_busy_wait(info);
  		if (retval < 0)
  			return retval;
  
  		lcd_write_control(info,
  				  LCD_TEXT_POS(info->fix.line_length * y + x));
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	retval = lcd_busy_wait(info);
  	if (retval < 0)
  		return retval;
  
  	if (cursor->enable)
  		lcd_write_control(info, LCD_CURSOR_ON);
  	else
  		lcd_write_control(info, LCD_CURSOR_OFF);
  
  	return 0;
  }
  
  static struct fb_ops cobalt_lcd_fbops = {
  	.owner		= THIS_MODULE,
  	.fb_read	= cobalt_lcdfb_read,
  	.fb_write	= cobalt_lcdfb_write,
  	.fb_blank	= cobalt_lcdfb_blank,
  	.fb_cursor	= cobalt_lcdfb_cursor,
  };
  
  static int cobalt_lcdfb_probe(struct platform_device *dev)
  {
  	struct fb_info *info;
  	struct resource *res;
  	int retval;
  
  	info = framebuffer_alloc(0, &dev->dev);
  	if (!info)
  		return -ENOMEM;
  
  	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
  	if (!res) {
  		framebuffer_release(info);
  		return -EBUSY;
  	}
  
  	info->screen_size = resource_size(res);
  	info->screen_base = devm_ioremap(&dev->dev, res->start,
  					 info->screen_size);
  	info->fbops = &cobalt_lcd_fbops;
  	info->fix = cobalt_lcdfb_fix;
  	info->fix.smem_start = res->start;
  	info->fix.smem_len = info->screen_size;
  	info->pseudo_palette = NULL;
  	info->par = NULL;
  	info->flags = FBINFO_DEFAULT;
  
  	retval = register_framebuffer(info);
  	if (retval < 0) {
  		framebuffer_release(info);
  		return retval;
  	}
  
  	platform_set_drvdata(dev, info);
  
  	lcd_clear(info);
  
  	fb_info(info, "Cobalt server LCD frame buffer device
  ");
  
  	return 0;
  }
  
  static int cobalt_lcdfb_remove(struct platform_device *dev)
  {
  	struct fb_info *info;
  
  	info = platform_get_drvdata(dev);
  	if (info) {
  		unregister_framebuffer(info);
  		framebuffer_release(info);
  	}
  
  	return 0;
  }
  
  static struct platform_driver cobalt_lcdfb_driver = {
  	.probe	= cobalt_lcdfb_probe,
  	.remove	= cobalt_lcdfb_remove,
  	.driver	= {
  		.name	= "cobalt-lcd",
  		.owner	= THIS_MODULE,
  	},
  };
  module_platform_driver(cobalt_lcdfb_driver);
  
  MODULE_LICENSE("GPL v2");
  MODULE_AUTHOR("Yoichi Yuasa");
  MODULE_DESCRIPTION("Cobalt server LCD frame buffer driver");