/*
 *      linux/drivers/video/maxinefb.c
 *
 *      DECstation 5000/xx onboard framebuffer support ... derived from:
 *      "HP300 Topcat framebuffer support (derived from macfb of all things)
 *      Phil Blundell <philb@gnu.org> 1998", the original code can be
 *      found in the file hpfb.c in the same directory.
 *
 *      DECstation related code Copyright (C) 1999,2000,2001 by
 *      Michael Engel <engel@unix-ag.org> and
 *      Karsten Merker <merker@linuxtag.org>.
 *      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.
 *
 */

/*
 * Changes:
 * 2001/01/27 removed debugging and testing code, fixed fb_ops
 *            initialization which had caused a crash before,
 *            general cleanup, first official release (KM)
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/fb.h>
#include <video/maxinefb.h>

/* bootinfo.h defines the machine type values, needed when checking */
/* whether are really running on a maxine, KM                       */
#include <asm/bootinfo.h>

static struct fb_info fb_info;

static const struct fb_var_screeninfo maxinefb_defined = {
        .xres =         1024,
        .yres =         768,
        .xres_virtual = 1024,
        .yres_virtual = 768,
        .bits_per_pixel =8,
        .activate =     FB_ACTIVATE_NOW,
        .height =       -1,
        .width =        -1,
        .vmode =        FB_VMODE_NONINTERLACED,
};

static struct fb_fix_screeninfo maxinefb_fix __initdata = {
        .id =           "Maxine",
        .smem_len =     (1024*768),
        .type =         FB_TYPE_PACKED_PIXELS,
        .visual =       FB_VISUAL_PSEUDOCOLOR,
        .line_length =  1024,
};

/* Handle the funny Inmos RamDAC/video controller ... */

void maxinefb_ims332_write_register(int regno, register unsigned int val)
{
        register unsigned char *regs = (char *) MAXINEFB_IMS332_ADDRESS;
        unsigned char *wptr;

        wptr = regs + 0xa0000 + (regno << 4);
        *((volatile unsigned int *) (regs)) = (val >> 8) & 0xff00;
        *((volatile unsigned short *) (wptr)) = val;
}

unsigned int maxinefb_ims332_read_register(int regno)
{
        register unsigned char *regs = (char *) MAXINEFB_IMS332_ADDRESS;
        unsigned char *rptr;
        register unsigned int j, k;

        rptr = regs + 0x80000 + (regno << 4);
        j = *((volatile unsigned short *) rptr);
        k = *((volatile unsigned short *) regs);

        return (j & 0xffff) | ((k & 0xff00) << 8);
}

/* Set the palette */
static int maxinefb_setcolreg(unsigned regno, unsigned red, unsigned green,
                              unsigned blue, unsigned transp, struct fb_info *info)
{
        /* value to be written into the palette reg. */
        unsigned long hw_colorvalue = 0;

        if (regno > 255)
                return 1;

        red   >>= 8;    /* The cmap fields are 16 bits    */
        green >>= 8;    /* wide, but the harware colormap */
        blue  >>= 8;    /* registers are only 8 bits wide */

        hw_colorvalue = (blue << 16) + (green << 8) + (red);

        maxinefb_ims332_write_register(IMS332_REG_COLOR_PALETTE + regno,
                                       hw_colorvalue);
        return 0;
}

static const struct fb_ops maxinefb_ops = {
        .owner          = THIS_MODULE,
        FB_DEFAULT_IOMEM_OPS,
        .fb_setcolreg   = maxinefb_setcolreg,
};

int __init maxinefb_init(void)
{
        unsigned long fboff;
        unsigned long fb_start;
        int i;

        if (fb_get_options("maxinefb", NULL))
                return -ENODEV;

        /* Validate we're on the proper machine type */
        if (mips_machtype != MACH_DS5000_XX) {
                return -EINVAL;
        }

        printk(KERN_INFO "Maxinefb: Personal DECstation detected\n");
        printk(KERN_INFO "Maxinefb: initializing onboard framebuffer\n");

        /* Framebuffer display memory base address */
        fb_start = DS5000_xx_ONBOARD_FBMEM_START;

        /* Clear screen */
        for (fboff = fb_start; fboff < fb_start + 0x1ffff; fboff++)
                *(volatile unsigned char *)fboff = 0x0;

        maxinefb_fix.smem_start = fb_start;

        /* erase hardware cursor */
        for (i = 0; i < 512; i++) {
                maxinefb_ims332_write_register(IMS332_REG_CURSOR_RAM + i,
                                               0);
                /*
                   if (i&0x8 == 0)
                   maxinefb_ims332_write_register (IMS332_REG_CURSOR_RAM + i, 0x0f);
                   else
                   maxinefb_ims332_write_register (IMS332_REG_CURSOR_RAM + i, 0xf0);
                 */
        }

        fb_info.fbops = &maxinefb_ops;
        fb_info.screen_base = (char *)maxinefb_fix.smem_start;
        fb_info.var = maxinefb_defined;
        fb_info.fix = maxinefb_fix;

        fb_alloc_cmap(&fb_info.cmap, 256, 0);

        if (register_framebuffer(&fb_info) < 0)
                return 1;
        return 0;
}

static void __exit maxinefb_exit(void)
{
        unregister_framebuffer(&fb_info);
}

#ifdef MODULE
MODULE_LICENSE("GPL");
#endif
module_init(maxinefb_init);
module_exit(maxinefb_exit);