/*
 * drivers/video/asiliantfb.c
 *  frame buffer driver for Asiliant 69000 chip
 *  Copyright (C) 2001-2003 Saito.K & Jeanne
 *
 *  from driver/video/chipsfb.c and,
 *
 *  drivers/video/asiliantfb.c -- frame buffer device for
 *  Asiliant 69030 chip (formerly Intel, formerly Chips & Technologies)
 *  Author: apc@agelectronics.co.uk
 *  Copyright (C) 2000 AG Electronics
 *  Note: the data sheets don't seem to be available from Asiliant.
 *  They are available by searching developer.intel.com, but are not otherwise
 *  linked to.
 *
 *  This driver should be portable with minimal effort to the 69000 display
 *  chip, and to the twin-display mode of the 69030.
 *  Contains code from Thomas Hhenleitner <th@visuelle-maschinen.de> (thanks)
 *
 *  Derived from the CT65550 driver chipsfb.c:
 *  Copyright (C) 1998 Paul Mackerras
 *  ...which was derived from the Powermac "chips" driver:
 *  Copyright (C) 1997 Fabio Riccardi.
 *  And from the frame buffer device for Open Firmware-initialized devices:
 *  Copyright (C) 1997 Geert Uytterhoeven.
 *
 *  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.
 */

#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/pci.h>
#include <asm/io.h>

/* Built in clock of the 69030 */
static const unsigned Fref = 14318180;

#define mmio_base (p->screen_base + 0x400000)

#define mm_write_ind(num, val, ap, dp)	do { \
	writeb((num), mmio_base + (ap)); writeb((val), mmio_base + (dp)); \
} while (0)

static void mm_write_xr(struct fb_info *p, u8 reg, u8 data)
{
	mm_write_ind(reg, data, 0x7ac, 0x7ad);
}
#define write_xr(num, val)	mm_write_xr(p, num, val)

static void mm_write_fr(struct fb_info *p, u8 reg, u8 data)
{
	mm_write_ind(reg, data, 0x7a0, 0x7a1);
}
#define write_fr(num, val)	mm_write_fr(p, num, val)

static void mm_write_cr(struct fb_info *p, u8 reg, u8 data)
{
	mm_write_ind(reg, data, 0x7a8, 0x7a9);
}
#define write_cr(num, val)	mm_write_cr(p, num, val)

static void mm_write_gr(struct fb_info *p, u8 reg, u8 data)
{
	mm_write_ind(reg, data, 0x79c, 0x79d);
}
#define write_gr(num, val)	mm_write_gr(p, num, val)

static void mm_write_sr(struct fb_info *p, u8 reg, u8 data)
{
	mm_write_ind(reg, data, 0x788, 0x789);
}
#define write_sr(num, val)	mm_write_sr(p, num, val)

static void mm_write_ar(struct fb_info *p, u8 reg, u8 data)
{
	readb(mmio_base + 0x7b4);
	mm_write_ind(reg, data, 0x780, 0x780);
}
#define write_ar(num, val)	mm_write_ar(p, num, val)

static int asiliantfb_pci_init(struct pci_dev *dp, const struct pci_device_id *);
static int asiliantfb_check_var(struct fb_var_screeninfo *var,
				struct fb_info *info);
static int asiliantfb_set_par(struct fb_info *info);
static int asiliantfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
				u_int transp, struct fb_info *info);

static struct fb_ops asiliantfb_ops = {
	.owner		= THIS_MODULE,
	.fb_check_var	= asiliantfb_check_var,
	.fb_set_par	= asiliantfb_set_par,
	.fb_setcolreg	= asiliantfb_setcolreg,
	.fb_fillrect	= cfb_fillrect,
	.fb_copyarea	= cfb_copyarea,
	.fb_imageblit	= cfb_imageblit,
};

/* Calculate the ratios for the dot clocks without using a single long long
 * value */
static void asiliant_calc_dclk2(u32 *ppixclock, u8 *dclk2_m, u8 *dclk2_n, u8 *dclk2_div)
{
	unsigned pixclock = *ppixclock;
	unsigned Ftarget = 1000000 * (1000000 / pixclock);
	unsigned n;
	unsigned best_error = 0xffffffff;
	unsigned best_m = 0xffffffff,
	         best_n = 0xffffffff;
	unsigned ratio;
	unsigned remainder;
	unsigned char divisor = 0;

	/* Calculate the frequency required. This is hard enough. */
	ratio = 1000000 / pixclock;
	remainder = 1000000 % pixclock;
	Ftarget = 1000000 * ratio + (1000000 * remainder) / pixclock;

	while (Ftarget < 100000000) {
		divisor += 0x10;
		Ftarget <<= 1;
	}

	ratio = Ftarget / Fref;
	remainder = Ftarget % Fref;

	/* This expresses the constraint that 150kHz <= Fref/n <= 5Mhz,
	 * together with 3 <= n <= 257. */
	for (n = 3; n <= 257; n++) {
		unsigned m = n * ratio + (n * remainder) / Fref;

		/* 3 <= m <= 257 */
		if (m >= 3 && m <= 257) {
			unsigned new_error = Ftarget * n >= Fref * m ?
					       ((Ftarget * n) - (Fref * m)) : ((Fref * m) - (Ftarget * n));
			if (new_error < best_error) {
				best_n = n;
				best_m = m;
				best_error = new_error;
			}
		}
		/* But if VLD = 4, then 4m <= 1028 */
		else if (m <= 1028) {
			/* remember there are still only 8-bits of precision in m, so
			 * avoid over-optimistic error calculations */
			unsigned new_error = Ftarget * n >= Fref * (m & ~3) ?
					       ((Ftarget * n) - (Fref * (m & ~3))) : ((Fref * (m & ~3)) - (Ftarget * n));
			if (new_error < best_error) {
				best_n = n;
				best_m = m;
				best_error = new_error;
			}
		}
	}
	if (best_m > 257)
		best_m >>= 2;	/* divide m by 4, and leave VCO loop divide at 4 */
	else
		divisor |= 4;	/* or set VCO loop divide to 1 */
	*dclk2_m = best_m - 2;
	*dclk2_n = best_n - 2;
	*dclk2_div = divisor;
	*ppixclock = pixclock;
	return;
}

static void asiliant_set_timing(struct fb_info *p)
{
	unsigned hd = p->var.xres / 8;
	unsigned hs = (p->var.xres + p->var.right_margin) / 8;
       	unsigned he = (p->var.xres + p->var.right_margin + p->var.hsync_len) / 8;
	unsigned ht = (p->var.left_margin + p->var.xres + p->var.right_margin + p->var.hsync_len) / 8;
	unsigned vd = p->var.yres;
	unsigned vs = p->var.yres + p->var.lower_margin;
	unsigned ve = p->var.yres + p->var.lower_margin + p->var.vsync_len;
	unsigned vt = p->var.upper_margin + p->var.yres + p->var.lower_margin + p->var.vsync_len;
	unsigned wd = (p->var.xres_virtual * ((p->var.bits_per_pixel+7)/8)) / 8;

	if ((p->var.xres == 640) && (p->var.yres == 480) && (p->var.pixclock == 39722)) {
	  write_fr(0x01, 0x02);  /* LCD */
	} else {
	  write_fr(0x01, 0x01);  /* CRT */
	}

	write_cr(0x11, (ve - 1) & 0x0f);
	write_cr(0x00, (ht - 5) & 0xff);
	write_cr(0x01, hd - 1);
	write_cr(0x02, hd);
	write_cr(0x03, ((ht - 1) & 0x1f) | 0x80);
	write_cr(0x04, hs);
	write_cr(0x05, (((ht - 1) & 0x20) <<2) | (he & 0x1f));
	write_cr(0x3c, (ht - 1) & 0xc0);
	write_cr(0x06, (vt - 2) & 0xff);
	write_cr(0x30, (vt - 2) >> 8);
	write_cr(0x07, 0x00);
	write_cr(0x08, 0x00);
	write_cr(0x09, 0x00);
	write_cr(0x10, (vs - 1) & 0xff);
	write_cr(0x32, ((vs - 1) >> 8) & 0xf);
	write_cr(0x11, ((ve - 1) & 0x0f) | 0x80);
	write_cr(0x12, (vd - 1) & 0xff);
	write_cr(0x31, ((vd - 1) & 0xf00) >> 8);
	write_cr(0x13, wd & 0xff);
	write_cr(0x41, (wd & 0xf00) >> 8);
	write_cr(0x15, (vs - 1) & 0xff);
	write_cr(0x33, ((vs - 1) >> 8) & 0xf);
	write_cr(0x38, ((ht - 5) & 0x100) >> 8);
	write_cr(0x16, (vt - 1) & 0xff);
	write_cr(0x18, 0x00);

	if (p->var.xres == 640) {
	  writeb(0xc7, mmio_base + 0x784);	/* set misc output reg */
	} else {
	  writeb(0x07, mmio_base + 0x784);	/* set misc output reg */
	}
}

static int asiliantfb_check_var(struct fb_var_screeninfo *var,
			     struct fb_info *p)
{
	unsigned long Ftarget, ratio, remainder;

	ratio = 1000000 / var->pixclock;
	remainder = 1000000 % var->pixclock;
	Ftarget = 1000000 * ratio + (1000000 * remainder) / var->pixclock;

	/* First check the constraint that the maximum post-VCO divisor is 32,
	 * and the maximum Fvco is 220MHz */
	if (Ftarget > 220000000 || Ftarget < 3125000) {
		printk(KERN_ERR "asiliantfb dotclock must be between 3.125 and 220MHz\n");
		return -ENXIO;
	}
	var->xres_virtual = var->xres;
	var->yres_virtual = var->yres;

	if (var->bits_per_pixel == 24) {
		var->red.offset = 16;
		var->green.offset = 8;
		var->blue.offset = 0;
		var->red.length = var->blue.length = var->green.length = 8;
	} else if (var->bits_per_pixel == 16) {
		switch (var->red.offset) {
			case 11:
				var->green.length = 6;
				break;
			case 10:
				var->green.length = 5;
				break;
			default:
				return -EINVAL;
		}
		var->green.offset = 5;
		var->blue.offset = 0;
		var->red.length = var->blue.length = 5;
	} else if (var->bits_per_pixel == 8) {
		var->red.offset = var->green.offset = var->blue.offset = 0;
		var->red.length = var->green.length = var->blue.length = 8;
	}
	return 0;
}

static int asiliantfb_set_par(struct fb_info *p)
{
	u8 dclk2_m;		/* Holds m-2 value for register */
	u8 dclk2_n;		/* Holds n-2 value for register */
	u8 dclk2_div;		/* Holds divisor bitmask */

	/* Set pixclock */
	asiliant_calc_dclk2(&p->var.pixclock, &dclk2_m, &dclk2_n, &dclk2_div);

	/* Set color depth */
	if (p->var.bits_per_pixel == 24) {
		write_xr(0x81, 0x16);	/* 24 bit packed color mode */
		write_xr(0x82, 0x00);	/* Disable palettes */
		write_xr(0x20, 0x20);	/* 24 bit blitter mode */
	} else if (p->var.bits_per_pixel == 16) {
		if (p->var.red.offset == 11)
			write_xr(0x81, 0x15);	/* 16 bit color mode */
		else
			write_xr(0x81, 0x14);	/* 15 bit color mode */
		write_xr(0x82, 0x00);	/* Disable palettes */
		write_xr(0x20, 0x10);	/* 16 bit blitter mode */
	} else if (p->var.bits_per_pixel == 8) {
		write_xr(0x0a, 0x02);	/* Linear */
		write_xr(0x81, 0x12);	/* 8 bit color mode */
		write_xr(0x82, 0x00);	/* Graphics gamma enable */
		write_xr(0x20, 0x00);	/* 8 bit blitter mode */
	}
	p->fix.line_length = p->var.xres * (p->var.bits_per_pixel >> 3);
	p->fix.visual = (p->var.bits_per_pixel == 8) ? FB_VISUAL_PSEUDOCOLOR : FB_VISUAL_TRUECOLOR;
	write_xr(0xc4, dclk2_m);
	write_xr(0xc5, dclk2_n);
	write_xr(0xc7, dclk2_div);
	/* Set up the CR registers */
	asiliant_set_timing(p);
	return 0;
}

static int asiliantfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
			     u_int transp, struct fb_info *p)
{
	if (regno > 255)
		return 1;
	red >>= 8;
	green >>= 8;
	blue >>= 8;

        /* Set hardware palete */
	writeb(regno, mmio_base + 0x790);
	udelay(1);
	writeb(red, mmio_base + 0x791);
	writeb(green, mmio_base + 0x791);
	writeb(blue, mmio_base + 0x791);

	if (regno < 16) {
		switch(p->var.red.offset) {
		case 10: /* RGB 555 */
			((u32 *)(p->pseudo_palette))[regno] =
				((red & 0xf8) << 7) |
				((green & 0xf8) << 2) |
				((blue & 0xf8) >> 3);
			break;
		case 11: /* RGB 565 */
			((u32 *)(p->pseudo_palette))[regno] =
				((red & 0xf8) << 8) |
				((green & 0xfc) << 3) |
				((blue & 0xf8) >> 3);
			break;
		case 16: /* RGB 888 */
			((u32 *)(p->pseudo_palette))[regno] =
				(red << 16)  |
				(green << 8) |
				(blue);
			break;
		}
	}

	return 0;
}

struct chips_init_reg {
	unsigned char addr;
	unsigned char data;
};

static struct chips_init_reg chips_init_sr[] =
{
	{0x00, 0x03},		/* Reset register */
	{0x01, 0x01},		/* Clocking mode */
	{0x02, 0x0f},		/* Plane mask */
	{0x04, 0x0e}		/* Memory mode */
};

static struct chips_init_reg chips_init_gr[] =
{
        {0x03, 0x00},		/* Data rotate */
	{0x05, 0x00},		/* Graphics mode */
	{0x06, 0x01},		/* Miscellaneous */
	{0x08, 0x00}		/* Bit mask */
};

static struct chips_init_reg chips_init_ar[] =
{
	{0x10, 0x01},		/* Mode control */
	{0x11, 0x00},		/* Overscan */
	{0x12, 0x0f},		/* Memory plane enable */
	{0x13, 0x00}		/* Horizontal pixel panning */
};

static struct chips_init_reg chips_init_cr[] =
{
	{0x0c, 0x00},		/* Start address high */
	{0x0d, 0x00},		/* Start address low */
	{0x40, 0x00},		/* Extended Start Address */
	{0x41, 0x00},		/* Extended Start Address */
	{0x14, 0x00},		/* Underline location */
	{0x17, 0xe3},		/* CRT mode control */
	{0x70, 0x00}		/* Interlace control */
};


static struct chips_init_reg chips_init_fr[] =
{
	{0x01, 0x02},
	{0x03, 0x08},
	{0x08, 0xcc},
	{0x0a, 0x08},
	{0x18, 0x00},
	{0x1e, 0x80},
	{0x40, 0x83},
	{0x41, 0x00},
	{0x48, 0x13},
	{0x4d, 0x60},
	{0x4e, 0x0f},

	{0x0b, 0x01},

	{0x21, 0x51},
	{0x22, 0x1d},
	{0x23, 0x5f},
	{0x20, 0x4f},
	{0x34, 0x00},
	{0x24, 0x51},
	{0x25, 0x00},
	{0x27, 0x0b},
	{0x26, 0x00},
	{0x37, 0x80},
	{0x33, 0x0b},
	{0x35, 0x11},
	{0x36, 0x02},
	{0x31, 0xea},
	{0x32, 0x0c},
	{0x30, 0xdf},
	{0x10, 0x0c},
	{0x11, 0xe0},
	{0x12, 0x50},
	{0x13, 0x00},
	{0x16, 0x03},
	{0x17, 0xbd},
	{0x1a, 0x00},
};


static struct chips_init_reg chips_init_xr[] =
{
	{0xce, 0x00},		/* set default memory clock */
	{0xcc, 200 },	        /* MCLK ratio M */
	{0xcd, 18  },	        /* MCLK ratio N */
	{0xce, 0x90},		/* MCLK divisor = 2 */

	{0xc4, 209 },
	{0xc5, 118 },
	{0xc7, 32  },
	{0xcf, 0x06},
	{0x09, 0x01},		/* IO Control - CRT controller extensions */
	{0x0a, 0x02},		/* Frame buffer mapping */
	{0x0b, 0x01},		/* PCI burst write */
	{0x40, 0x03},		/* Memory access control */
	{0x80, 0x82},		/* Pixel pipeline configuration 0 */
	{0x81, 0x12},		/* Pixel pipeline configuration 1 */
	{0x82, 0x08},		/* Pixel pipeline configuration 2 */

	{0xd0, 0x0f},
	{0xd1, 0x01},
};

static void chips_hw_init(struct fb_info *p)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(chips_init_xr); ++i)
		write_xr(chips_init_xr[i].addr, chips_init_xr[i].data);
	write_xr(0x81, 0x12);
	write_xr(0x82, 0x08);
	write_xr(0x20, 0x00);
	for (i = 0; i < ARRAY_SIZE(chips_init_sr); ++i)
		write_sr(chips_init_sr[i].addr, chips_init_sr[i].data);
	for (i = 0; i < ARRAY_SIZE(chips_init_gr); ++i)
		write_gr(chips_init_gr[i].addr, chips_init_gr[i].data);
	for (i = 0; i < ARRAY_SIZE(chips_init_ar); ++i)
		write_ar(chips_init_ar[i].addr, chips_init_ar[i].data);
	/* Enable video output in attribute index register */
	writeb(0x20, mmio_base + 0x780);
	for (i = 0; i < ARRAY_SIZE(chips_init_cr); ++i)
		write_cr(chips_init_cr[i].addr, chips_init_cr[i].data);
	for (i = 0; i < ARRAY_SIZE(chips_init_fr); ++i)
		write_fr(chips_init_fr[i].addr, chips_init_fr[i].data);
}

static struct fb_fix_screeninfo asiliantfb_fix = {
	.id =		"Asiliant 69000",
	.type =		FB_TYPE_PACKED_PIXELS,
	.visual =	FB_VISUAL_PSEUDOCOLOR,
	.accel =	FB_ACCEL_NONE,
	.line_length =	640,
	.smem_len =	0x200000,	/* 2MB */
};

static struct fb_var_screeninfo asiliantfb_var = {
	.xres 		= 640,
	.yres 		= 480,
	.xres_virtual 	= 640,
	.yres_virtual 	= 480,
	.bits_per_pixel = 8,
	.red 		= { .length = 8 },
	.green 		= { .length = 8 },
	.blue 		= { .length = 8 },
	.height 	= -1,
	.width 		= -1,
	.vmode 		= FB_VMODE_NONINTERLACED,
	.pixclock 	= 39722,
	.left_margin 	= 48,
	.right_margin 	= 16,
	.upper_margin 	= 33,
	.lower_margin 	= 10,
	.hsync_len 	= 96,
	.vsync_len 	= 2,
};

static int init_asiliant(struct fb_info *p, unsigned long addr)
{
	int err;

	p->fix			= asiliantfb_fix;
	p->fix.smem_start	= addr;
	p->var			= asiliantfb_var;
	p->fbops		= &asiliantfb_ops;
	p->flags		= FBINFO_DEFAULT;

	err = fb_alloc_cmap(&p->cmap, 256, 0);
	if (err) {
		printk(KERN_ERR "C&T 69000 fb failed to alloc cmap memory\n");
		return err;
	}

	err = register_framebuffer(p);
	if (err < 0) {
		printk(KERN_ERR "C&T 69000 framebuffer failed to register\n");
		fb_dealloc_cmap(&p->cmap);
		return err;
	}

	fb_info(p, "Asiliant 69000 frame buffer (%dK RAM detected)\n",
		p->fix.smem_len / 1024);

	writeb(0xff, mmio_base + 0x78c);
	chips_hw_init(p);
	return 0;
}

static int asiliantfb_pci_init(struct pci_dev *dp,
			       const struct pci_device_id *ent)
{
	unsigned long addr, size;
	struct fb_info *p;
	int err;

	if ((dp->resource[0].flags & IORESOURCE_MEM) == 0)
		return -ENODEV;
	addr = pci_resource_start(dp, 0);
	size = pci_resource_len(dp, 0);
	if (addr == 0)
		return -ENODEV;
	if (!request_mem_region(addr, size, "asiliantfb"))
		return -EBUSY;

	p = framebuffer_alloc(sizeof(u32) * 16, &dp->dev);
	if (!p)	{
		release_mem_region(addr, size);
		return -ENOMEM;
	}
	p->pseudo_palette = p->par;
	p->par = NULL;

	p->screen_base = ioremap(addr, 0x800000);
	if (p->screen_base == NULL) {
		release_mem_region(addr, size);
		framebuffer_release(p);
		return -ENOMEM;
	}

	pci_write_config_dword(dp, 4, 0x02800083);
	writeb(3, p->screen_base + 0x400784);

	err = init_asiliant(p, addr);
	if (err) {
		iounmap(p->screen_base);
		release_mem_region(addr, size);
		framebuffer_release(p);
		return err;
	}

	pci_set_drvdata(dp, p);
	return 0;
}

static void asiliantfb_remove(struct pci_dev *dp)
{
	struct fb_info *p = pci_get_drvdata(dp);

	unregister_framebuffer(p);
	fb_dealloc_cmap(&p->cmap);
	iounmap(p->screen_base);
	release_mem_region(pci_resource_start(dp, 0), pci_resource_len(dp, 0));
	framebuffer_release(p);
}

static struct pci_device_id asiliantfb_pci_tbl[] = {
	{ PCI_VENDOR_ID_CT, PCI_DEVICE_ID_CT_69000, PCI_ANY_ID, PCI_ANY_ID },
	{ 0 }
};

MODULE_DEVICE_TABLE(pci, asiliantfb_pci_tbl);

static struct pci_driver asiliantfb_driver = {
	.name =		"asiliantfb",
	.id_table =	asiliantfb_pci_tbl,
	.probe =	asiliantfb_pci_init,
	.remove =	asiliantfb_remove,
};

static int __init asiliantfb_init(void)
{
	if (fb_get_options("asiliantfb", NULL))
		return -ENODEV;

	return pci_register_driver(&asiliantfb_driver);
}

module_init(asiliantfb_init);

static void __exit asiliantfb_exit(void)
{
	pci_unregister_driver(&asiliantfb_driver);
}

MODULE_LICENSE("GPL");