/*
   * linux/drivers/video/arcfb.c -- FB driver for Arc monochrome LCD board
   *
   * Copyright (C) 2005, Jaya Kumar <jayalk@intworks.biz>

   *
   * 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.
   *
   * Layout is based on skeletonfb.c by James Simmons and Geert Uytterhoeven.
   *
   * This driver was written to be used with the Arc LCD board. Arc uses a
   * set of KS108 chips that control individual 64x64 LCD matrices. The board
   * can be paneled in a variety of setups such as 2x1=128x64, 4x4=256x256 and
   * so on. The interface between the board and the host is TTL based GPIO. The
   * GPIO requirements are 8 writable data lines and 4+n lines for control. On a
   * GPIO-less system, the board can be tested by connecting the respective sigs
   * up to a parallel port connector. The driver requires the IO addresses for
   * data and control GPIO at load time. It is unable to probe for the
   * existence of the LCD so it must be told at load time whether it should
   * be enabled or not.
   *
   * Todo:
   * - testing with 4x4
   * - testing with interrupt hw
   *
   * General notes:
   * - User must set tuhold. It's in microseconds. According to the 108 spec,
   *   the hold time is supposed to be at least 1 microsecond.
   * - User must set num_cols=x num_rows=y, eg: x=2 means 128
   * - User must set arcfb_enable=1 to enable it
   * - User must set dio_addr=0xIOADDR cio_addr=0xIOADDR
   *
   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/errno.h>
  #include <linux/string.h>
  #include <linux/mm.h>

  #include <linux/vmalloc.h>
  #include <linux/delay.h>
  #include <linux/interrupt.h>
  #include <linux/fb.h>
  #include <linux/init.h>
  #include <linux/arcfb.h>

  #include <linux/platform_device.h>

  #include <linux/uaccess.h>

  
  #define floor8(a) (a&(~0x07))
  #define floorXres(a,xres) (a&(~(xres - 1)))
  #define iceil8(a) (((int)((a+7)/8))*8)
  #define ceil64(a) (a|0x3F)
  #define ceilXres(a,xres) (a|(xres - 1))
  
  /* ks108 chipset specific defines and code */
  
  #define KS_SET_DPY_START_LINE 	0xC0
  #define KS_SET_PAGE_NUM 	0xB8
  #define KS_SET_X 		0x40
  #define KS_CEHI 		0x01
  #define KS_CELO 		0x00
  #define KS_SEL_CMD 		0x08
  #define KS_SEL_DATA 		0x00
  #define KS_DPY_ON 		0x3F
  #define KS_DPY_OFF 		0x3E
  #define KS_INTACK 		0x40
  #define KS_CLRINT		0x02
  
  struct arcfb_par {
  	unsigned long dio_addr;
  	unsigned long cio_addr;
  	unsigned long c2io_addr;
  	atomic_t ref_count;
  	unsigned char cslut[9];
  	struct fb_info *info;
  	unsigned int irq;
  	spinlock_t lock;
  };

  static struct fb_fix_screeninfo arcfb_fix __devinitdata = {

  	.id =		"arcfb",
  	.type =		FB_TYPE_PACKED_PIXELS,
  	.visual =	FB_VISUAL_MONO01,
  	.xpanstep =	0,
  	.ypanstep =	1,
  	.ywrapstep =	0,
  	.accel =	FB_ACCEL_NONE,
  };

  static struct fb_var_screeninfo arcfb_var __devinitdata = {

  	.xres		= 128,
  	.yres		= 64,
  	.xres_virtual	= 128,
  	.yres_virtual	= 64,
  	.bits_per_pixel	= 1,
  	.nonstd		= 1,
  };
  
  static unsigned long num_cols;
  static unsigned long num_rows;
  static unsigned long dio_addr;
  static unsigned long cio_addr;
  static unsigned long c2io_addr;
  static unsigned long splashval;
  static unsigned long tuhold;
  static unsigned int nosplash;
  static unsigned int arcfb_enable;
  static unsigned int irq;
  
  static DECLARE_WAIT_QUEUE_HEAD(arcfb_waitq);
  
  static void ks108_writeb_ctl(struct arcfb_par *par,
  				unsigned int chipindex, unsigned char value)
  {
  	unsigned char chipselval = par->cslut[chipindex];
  
  	outb(chipselval|KS_CEHI|KS_SEL_CMD, par->cio_addr);
  	outb(value, par->dio_addr);
  	udelay(tuhold);
  	outb(chipselval|KS_CELO|KS_SEL_CMD, par->cio_addr);
  }
  
  static void ks108_writeb_mainctl(struct arcfb_par *par, unsigned char value)
  {
  
  	outb(value, par->cio_addr);
  	udelay(tuhold);
  }
  
  static unsigned char ks108_readb_ctl2(struct arcfb_par *par)
  {
  	return inb(par->c2io_addr);
  }
  
  static void ks108_writeb_data(struct arcfb_par *par,
  				unsigned int chipindex, unsigned char value)
  {
  	unsigned char chipselval = par->cslut[chipindex];
  
  	outb(chipselval|KS_CEHI|KS_SEL_DATA, par->cio_addr);
  	outb(value, par->dio_addr);
  	udelay(tuhold);
  	outb(chipselval|KS_CELO|KS_SEL_DATA, par->cio_addr);
  }
  
  static void ks108_set_start_line(struct arcfb_par *par,
  				unsigned int chipindex, unsigned char y)
  {
  	ks108_writeb_ctl(par, chipindex, KS_SET_DPY_START_LINE|y);
  }
  
  static void ks108_set_yaddr(struct arcfb_par *par,
  				unsigned int chipindex, unsigned char y)
  {
  	ks108_writeb_ctl(par, chipindex, KS_SET_PAGE_NUM|y);
  }
  
  static void ks108_set_xaddr(struct arcfb_par *par,
  				unsigned int chipindex, unsigned char x)
  {
  	ks108_writeb_ctl(par, chipindex, KS_SET_X|x);
  }
  
  static void ks108_clear_lcd(struct arcfb_par *par, unsigned int chipindex)
  {
  	int i,j;
  
  	for (i = 0; i <= 8; i++) {
  		ks108_set_yaddr(par, chipindex, i);
  		ks108_set_xaddr(par, chipindex, 0);
  		for (j = 0; j < 64; j++) {
  			ks108_writeb_data(par, chipindex,
  				(unsigned char) splashval);
  		}
  	}
  }
  
  /* main arcfb functions */
  
  static int arcfb_open(struct fb_info *info, int user)
  {
  	struct arcfb_par *par = info->par;
  
  	atomic_inc(&par->ref_count);
  	return 0;
  }
  
  static int arcfb_release(struct fb_info *info, int user)
  {
  	struct arcfb_par *par = info->par;
  	int count = atomic_read(&par->ref_count);
  
  	if (!count)
  		return -EINVAL;
  	atomic_dec(&par->ref_count);
  	return 0;
  }
  
  static int arcfb_pan_display(struct fb_var_screeninfo *var,
  				struct fb_info *info)
  {
  	int i;
  	struct arcfb_par *par = info->par;
  
  	if ((var->vmode & FB_VMODE_YWRAP) && (var->yoffset < 64)
  		&& (info->var.yres <= 64)) {
  		for (i = 0; i < num_cols; i++) {
  			ks108_set_start_line(par, i, var->yoffset);
  		}
  		info->var.yoffset = var->yoffset;
  		return 0;
  	}
  
  	return -EINVAL;
  }

  static irqreturn_t arcfb_interrupt(int vec, void *dev_instance)

  {
  	struct fb_info *info = dev_instance;
  	unsigned char ctl2status;
  	struct arcfb_par *par = info->par;
  
  	ctl2status = ks108_readb_ctl2(par);
  
  	if (!(ctl2status & KS_INTACK)) /* not arc generated interrupt */
  		return IRQ_NONE;
  
  	ks108_writeb_mainctl(par, KS_CLRINT);
  
  	spin_lock(&par->lock);
          if (waitqueue_active(&arcfb_waitq)) {
                  wake_up(&arcfb_waitq);
          }
  	spin_unlock(&par->lock);
  
  	return IRQ_HANDLED;
  }
  
  /*
   * here we handle a specific page on the lcd. the complexity comes from
   * the fact that the fb is laidout in 8xX vertical columns. we extract
   * each write of 8 vertical pixels. then we shift out as we move along
   * X. That's what rightshift does. bitmask selects the desired input bit.
   */
  static void arcfb_lcd_update_page(struct arcfb_par *par, unsigned int upper,
  		unsigned int left, unsigned int right, unsigned int distance)
  {
  	unsigned char *src;
  	unsigned int xindex, yindex, chipindex, linesize;

  	int i;

  	unsigned char val;
  	unsigned char bitmask, rightshift;
  
  	xindex = left >> 6;
  	yindex = upper >> 6;
  	chipindex = (xindex + (yindex*num_cols));
  
  	ks108_set_yaddr(par, chipindex, upper/8);
  
  	linesize = par->info->var.xres/8;

  	src = (unsigned char __force *) par->info->screen_base + (left/8) +
  		(upper * linesize);

  	ks108_set_xaddr(par, chipindex, left);
  
  	bitmask=1;
  	rightshift=0;
  	while (left <= right) {
  		val = 0;
  		for (i = 0; i < 8; i++) {
  			if ( i > rightshift) {
  				val |= (*(src + (i*linesize)) & bitmask)
  						<< (i - rightshift);
  			} else {
  				val |= (*(src + (i*linesize)) & bitmask)
  						 >> (rightshift - i);
  			}
  		}
  		ks108_writeb_data(par, chipindex, val);
  		left++;

  		if (bitmask == 0x80) {
  			bitmask = 1;
  			src++;
  			rightshift=0;
  		} else {
  			bitmask <<= 1;
  			rightshift++;
  		}
  	}
  }
  
  /*
   * here we handle the entire vertical page of the update. we write across
   * lcd chips. update_page uses the upper/left values to decide which
   * chip to select for the right. upper is needed for setting the page
   * desired for the write.
   */
  static void arcfb_lcd_update_vert(struct arcfb_par *par, unsigned int top,
  		unsigned int bottom, unsigned int left, unsigned int right)
  {
  	unsigned int distance, upper, lower;
  
  	distance = (bottom - top) + 1;
  	upper = top;
  	lower = top + 7;
  
  	while (distance > 0) {
  		distance -= 8;
  		arcfb_lcd_update_page(par, upper, left, right, 8);
  		upper = lower + 1;
  		lower = upper + 7;
  	}
  }
  
  /*
   * here we handle horizontal blocks for the update. update_vert will
   * handle spaning multiple pages. we break out each horizontal
   * block in to individual blocks no taller than 64 pixels.
   */
  static void arcfb_lcd_update_horiz(struct arcfb_par *par, unsigned int left,
  			unsigned int right, unsigned int top, unsigned int h)
  {
  	unsigned int distance, upper, lower;
  
  	distance = h;
  	upper = floor8(top);
  	lower = min(upper + distance - 1, ceil64(upper));
  
  	while (distance > 0) {
  		distance -= ((lower - upper) + 1 );
  		arcfb_lcd_update_vert(par, upper, lower, left, right);
  		upper = lower + 1;
  		lower = min(upper + distance - 1, ceil64(upper));
  	}
  }
  
  /*
   * here we start the process of spliting out the fb update into
   * individual blocks of pixels. we end up spliting into 64x64 blocks
   * and finally down to 64x8 pages.
   */
  static void arcfb_lcd_update(struct arcfb_par *par, unsigned int dx,
  			unsigned int dy, unsigned int w, unsigned int h)
  {
  	unsigned int left, right, distance, y;
  
  	/* align the request first */
  	y = floor8(dy);
  	h += dy - y;
  	h = iceil8(h);
  
  	distance = w;
  	left = dx;
  	right = min(left + w - 1, ceil64(left));
  
  	while (distance > 0) {
  		arcfb_lcd_update_horiz(par, left, right, y, h);
  		distance -= ((right - left) + 1);
  		left = right + 1;
  		right = min(left + distance - 1, ceil64(left));
  	}
  }

  static void arcfb_fillrect(struct fb_info *info,
  			   const struct fb_fillrect *rect)

  {
  	struct arcfb_par *par = info->par;

  	sys_fillrect(info, rect);

  
  	/* update the physical lcd */
  	arcfb_lcd_update(par, rect->dx, rect->dy, rect->width, rect->height);
  }

  static void arcfb_copyarea(struct fb_info *info,
  			   const struct fb_copyarea *area)

  {
  	struct arcfb_par *par = info->par;

  	sys_copyarea(info, area);

  
  	/* update the physical lcd */
  	arcfb_lcd_update(par, area->dx, area->dy, area->width, area->height);
  }

  static void arcfb_imageblit(struct fb_info *info, const struct fb_image *image)

  {
  	struct arcfb_par *par = info->par;

  	sys_imageblit(info, image);

  
  	/* update the physical lcd */
  	arcfb_lcd_update(par, image->dx, image->dy, image->width,
  				image->height);
  }

  static int arcfb_ioctl(struct fb_info *info,
  			  unsigned int cmd, unsigned long arg)

  {
  	void __user *argp = (void __user *)arg;
  	struct arcfb_par *par = info->par;
  	unsigned long flags;
  
  	switch (cmd) {
  		case FBIO_WAITEVENT:
  		{
  			DEFINE_WAIT(wait);
  			/* illegal to wait on arc if no irq will occur */
  			if (!par->irq)
  				return -EINVAL;
  
  			/* wait until the Arc has generated an interrupt
  			 * which will wake us up */
  			spin_lock_irqsave(&par->lock, flags);
  			prepare_to_wait(&arcfb_waitq, &wait,
  					TASK_INTERRUPTIBLE);
  			spin_unlock_irqrestore(&par->lock, flags);
  			schedule();
  			finish_wait(&arcfb_waitq, &wait);
  		}
  		case FBIO_GETCONTROL2:
  		{
  			unsigned char ctl2;
  
  			ctl2 = ks108_readb_ctl2(info->par);
  			if (copy_to_user(argp, &ctl2, sizeof(ctl2)))
  				return -EFAULT;
  			return 0;
  		}
  		default:
  			return -EINVAL;
  	}
  }
  
  /*
   * this is the access path from userspace. they can seek and write to
   * the fb. it's inefficient for them to do anything less than 64*8
   * writes since we update the lcd in each write() anyway.
   */

  static ssize_t arcfb_write(struct fb_info *info, const char __user *buf,
  			   size_t count, loff_t *ppos)

  {
  	/* modded from epson 1355 */

  	unsigned long p;
  	int err=-EINVAL;
  	unsigned int fbmemlength,x,y,w,h, bitppos, startpos, endpos, bitcount;
  	struct arcfb_par *par;
  	unsigned int xres;
  
  	p = *ppos;

  	par = info->par;

  	xres = info->var.xres;
  	fbmemlength = (xres * info->var.yres)/8;
  
  	if (p > fbmemlength)
  		return -ENOSPC;
  
  	err = 0;
  	if ((count + p) > fbmemlength) {
  		count = fbmemlength - p;
  		err = -ENOSPC;
  	}
  
  	if (count) {
  		char *base_addr;

  		base_addr = (char __force *)info->screen_base;

  		count -= copy_from_user(base_addr + p, buf, count);
  		*ppos += count;
  		err = -EFAULT;
  	}
  
  
  	bitppos = p*8;
  	startpos = floorXres(bitppos, xres);
  	endpos = ceilXres((bitppos + (count*8)), xres);
  	bitcount = endpos - startpos;
  
  	x = startpos % xres;
  	y = startpos / xres;
  	w = xres;
  	h = bitcount / xres;
  	arcfb_lcd_update(par, x, y, w, h);
  
  	if (count)
  		return count;
  	return err;
  }

  static struct fb_ops arcfb_ops = {
  	.owner		= THIS_MODULE,
  	.fb_open	= arcfb_open,

  	.fb_read        = fb_sys_read,

  	.fb_write	= arcfb_write,
  	.fb_release	= arcfb_release,
  	.fb_pan_display	= arcfb_pan_display,
  	.fb_fillrect	= arcfb_fillrect,
  	.fb_copyarea	= arcfb_copyarea,
  	.fb_imageblit	= arcfb_imageblit,

  	.fb_ioctl 	= arcfb_ioctl,
  };

  static int __devinit arcfb_probe(struct platform_device *dev)

  {

  	struct fb_info *info;
  	int retval = -ENOMEM;
  	int videomemorysize;
  	unsigned char *videomemory;
  	struct arcfb_par *par;
  	int i;
  
  	videomemorysize = (((64*64)*num_cols)*num_rows)/8;
  
  	/* We need a flat backing store for the Arc's
  	   less-flat actual paged framebuffer */

  	videomemory = vzalloc(videomemorysize);
  	if (!videomemory)

  		return retval;

  	info = framebuffer_alloc(sizeof(struct arcfb_par), &dev->dev);
  	if (!info)
  		goto err;
  
  	info->screen_base = (char __iomem *)videomemory;
  	info->fbops = &arcfb_ops;
  
  	info->var = arcfb_var;
  	info->fix = arcfb_fix;
  	par = info->par;
  	par->info = info;
  
  	if (!dio_addr || !cio_addr || !c2io_addr) {
  		printk(KERN_WARNING "no IO addresses supplied
  ");
  		goto err1;
  	}
  	par->dio_addr = dio_addr;
  	par->cio_addr = cio_addr;
  	par->c2io_addr = c2io_addr;
  	par->cslut[0] = 0x00;
  	par->cslut[1] = 0x06;
  	info->flags = FBINFO_FLAG_DEFAULT;
  	spin_lock_init(&par->lock);
  	retval = register_framebuffer(info);
  	if (retval < 0)
  		goto err1;

  	platform_set_drvdata(dev, info);

  	if (irq) {
  		par->irq = irq;

  		if (request_irq(par->irq, &arcfb_interrupt, IRQF_SHARED,

  				"arcfb", info)) {
  			printk(KERN_INFO
  				"arcfb: Failed req IRQ %d
  ", par->irq);
  			goto err1;
  		}
  	}
  	printk(KERN_INFO
  	       "fb%d: Arc frame buffer device, using %dK of video memory
  ",
  	       info->node, videomemorysize >> 10);
  
  	/* this inits the lcd but doesn't clear dirty pixels */
  	for (i = 0; i < num_cols * num_rows; i++) {
  		ks108_writeb_ctl(par, i, KS_DPY_OFF);
  		ks108_set_start_line(par, i, 0);
  		ks108_set_yaddr(par, i, 0);
  		ks108_set_xaddr(par, i, 0);
  		ks108_writeb_ctl(par, i, KS_DPY_ON);
  	}
  
  	/* if we were told to splash the screen, we just clear it */
  	if (!nosplash) {
  		for (i = 0; i < num_cols * num_rows; i++) {
  			printk(KERN_INFO "fb%d: splashing lcd %d
  ",
  				info->node, i);
  			ks108_set_start_line(par, i, 0);
  			ks108_clear_lcd(par, i);
  		}
  	}
  
  	return 0;
  err1:
  	framebuffer_release(info);
  err:
  	vfree(videomemory);
  	return retval;
  }

  static int __devexit arcfb_remove(struct platform_device *dev)

  {

  	struct fb_info *info = platform_get_drvdata(dev);

  
  	if (info) {
  		unregister_framebuffer(info);

  		vfree((void __force *)info->screen_base);

  		framebuffer_release(info);
  	}
  	return 0;
  }

  static struct platform_driver arcfb_driver = {

  	.probe	= arcfb_probe,

  	.remove = __devexit_p(arcfb_remove),

  	.driver	= {
  		.name	= "arcfb",
  	},

  };

  static struct platform_device *arcfb_device;

  
  static int __init arcfb_init(void)
  {
  	int ret;
  
  	if (!arcfb_enable)
  		return -ENXIO;

  	ret = platform_driver_register(&arcfb_driver);

  	if (!ret) {

  		arcfb_device = platform_device_alloc("arcfb", 0);
  		if (arcfb_device) {
  			ret = platform_device_add(arcfb_device);
  		} else {
  			ret = -ENOMEM;
  		}
  		if (ret) {
  			platform_device_put(arcfb_device);

  			platform_driver_unregister(&arcfb_driver);

  		}

  	}
  	return ret;
  
  }
  
  static void __exit arcfb_exit(void)
  {

  	platform_device_unregister(arcfb_device);

  	platform_driver_unregister(&arcfb_driver);

  }
  
  module_param(num_cols, ulong, 0);
  MODULE_PARM_DESC(num_cols, "Num horiz panels, eg: 2 = 128 bit wide");
  module_param(num_rows, ulong, 0);
  MODULE_PARM_DESC(num_rows, "Num vert panels, eg: 1 = 64 bit high");
  module_param(nosplash, uint, 0);
  MODULE_PARM_DESC(nosplash, "Disable doing the splash screen");
  module_param(arcfb_enable, uint, 0);
  MODULE_PARM_DESC(arcfb_enable, "Enable communication with Arc board");
  module_param(dio_addr, ulong, 0);
  MODULE_PARM_DESC(dio_addr, "IO address for data, eg: 0x480");
  module_param(cio_addr, ulong, 0);
  MODULE_PARM_DESC(cio_addr, "IO address for control, eg: 0x400");
  module_param(c2io_addr, ulong, 0);
  MODULE_PARM_DESC(c2io_addr, "IO address for secondary control, eg: 0x408");
  module_param(splashval, ulong, 0);
  MODULE_PARM_DESC(splashval, "Splash pattern: 0xFF is black, 0x00 is green");
  module_param(tuhold, ulong, 0);
  MODULE_PARM_DESC(tuhold, "Time to hold between strobing data to Arc board");
  module_param(irq, uint, 0);
  MODULE_PARM_DESC(irq, "IRQ for the Arc board");
  
  module_init(arcfb_init);
  module_exit(arcfb_exit);
  
  MODULE_DESCRIPTION("fbdev driver for Arc monochrome LCD board");
  MODULE_AUTHOR("Jaya Kumar");
  MODULE_LICENSE("GPL");