/*
 * 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/aperture.h>
#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 const struct fb_ops asiliantfb_ops = {
        .owner          = THIS_MODULE,
        FB_DEFAULT_IOMEM_OPS,
        .fb_check_var   = asiliantfb_check_var,
        .fb_set_par     = asiliantfb_set_par,
        .fb_setcolreg   = asiliantfb_setcolreg,
};

/* 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;
        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;

        if (!var->pixclock)
                return -EINVAL;

        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 const 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 const 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;

        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;

        err = aperture_remove_conflicting_pci_devices(dp, "asiliantfb");
        if (err)
                return 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 const 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_modesetting_disabled("asiliantfb"))
                return -ENODEV;

        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");