/*      $NetBSD: vga.c,v 1.6 2009/03/18 10:22:34 cegger Exp $   */

/*-
 * Copyright (C) 1995-1997 Gary Thomas (gdt@linuxppc.org)
 * All rights reserved.
 *
 * VGA 'glass TTY' emulator
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Gary Thomas.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifdef CONS_VGA
#include <lib/libsa/stand.h>
#include <lib/libkern/libkern.h>
#include "boot.h"

#define COL             80
#define ROW             25
#define CHR             2
#define MONO_BASE       0x3B4
#define MONO_BUF        0xB0000
#define CGA_BASE        0x3D4
#define CGA_BUF         0xB8000

u_char background = 0;  /* Black */
u_char foreground = 7;  /* White */

u_int addr_6845;
u_short *Crtat;
int lastpos;
int scroll;

/*
 * The current state of virtual displays
 */
struct screen {
        u_short *cp;            /* the current character address */
        enum state {
                NORMAL,                 /* no pending escape */
                ESC,                    /* saw ESC */
                EBRAC,                  /* saw ESC[ */
                EBRACEQ                 /* saw ESC[= */
        } state;                /* command parser state */
        int     cx;             /* the first escape seq argument */
        int     cy;             /* the second escap seq argument */
        int     *accp;          /* pointer to the current processed argument */
        int     row;            /* current column */
        int     so;             /* standout mode */
        u_short color;          /* normal character color */
        u_short color_so;       /* standout color */
        u_short save_color;     /* saved normal color */
        u_short save_color_so;  /* saved standout color */
} screen;

/*
 * Color and attributes for normal, standout and kernel output
 * are stored in the least-significant byte of a u_short
 * so they don't have to be shifted for use.
 * This is all byte-order dependent.
 */
#define CATTR(x) (x)            /* store color/attributes un-shifted */
#define ATTR_ADDR(which) (((u_char *)&(which))+1) /* address of attributes */

u_short pccolor;                /* color/attributes for tty output */
u_short pccolor_so;             /* color/attributes, standout mode */

static void cursor(void);
static void initscreen(void);
void fillw(u_short, u_short *, int);
void video_on(void);
void video_off(void);

/*
 * cursor() sets an offset (0-1999) into the 80x25 text area   
 */
static void
cursor(void)
{
        int pos = screen.cp - Crtat;

        if (lastpos != pos) {
                outb(addr_6845, 14);
                outb(addr_6845+1, pos >> 8);
                outb(addr_6845, 15);
                outb(addr_6845+1, pos);
                lastpos = pos;
        }
}

static void
initscreen(void)
{
        struct screen *d = &screen;

        pccolor = CATTR((background<<4)|foreground);
        pccolor_so = CATTR((foreground<<4)|background);
        d->color = pccolor;
        d->save_color = pccolor;
        d->color_so = pccolor_so;
        d->save_color_so = pccolor_so;
}


#define wrtchar(c, d) { \
        *(d->cp) = c; \
        d->cp++; \
        d->row++; \
}

void
fillw(u_short val, u_short *buf, int num)
{
        /* Need to byte swap value */
        u_short tmp;

        tmp = val;
        while (num-- > 0)
                *buf++ = tmp;
}

/*
 * vga_putc (nee sput) has support for emulation of the 'ibmpc' termcap entry.
 * This is a bare-bones implementation of a bare-bones entry
 * One modification: Change li#24 to li#25 to reflect 25 lines
 * "ca" is the color/attributes value (left-shifted by 8)
 * or 0 if the current regular color for that screen is to be used.
 */
void 
vga_putc(int c)
{
        struct screen *d = &screen;
        u_short *base;
        int i, j;
        u_short *pp;

        base = Crtat;

        switch (d->state) {
        case NORMAL:
                switch (c) {
                case 0x0:               /* Ignore pad characters */
                        return;

                case 0x1B:
                        d->state = ESC;
                        break;

                case '\t':
                        do {
                                wrtchar(d->color | ' ', d);
                        } while (d->row % 8);
                        break;

                case '\b':  /* non-destructive backspace */
                        if (d->cp > base) {
                                d->cp--;
                                d->row--;
                                if (d->row < 0)
                                        d->row += COL;  /* prev column */
                        }
                        break;

                case '\n':
                        d->cp += COL;
                case '\r':
                        d->cp -= d->row;
                        d->row = 0;
                        break;

                case '\007':
                        break;

                default:
                        if (d->so) {
                                wrtchar(d->color_so|(c<<8), d); 
                        } else {
                                wrtchar(d->color | (c<<8), d); 
                        }
                        if (d->row >= COL)
                                d->row = 0;
                        break;
                }
                break;

        case EBRAC:
                /*
                 * In this state, the action at the end of the switch
                 * on the character type is to go to NORMAL state,
                 * and intermediate states do a return rather than break.
                 */
                switch (c) {
                case 'm':
                        d->so = d->cx;
                        break;

                case 'A': /* back one row */
                        if (d->cp >= base + COL)
                                d->cp -= COL;
                        break;

                case 'B': /* down one row */
                        d->cp += COL;
                        break;

                case 'C': /* right cursor */
                        d->cp++;
                        d->row++;
                        break;

                case 'D': /* left cursor */
                        if (d->cp > base) {
                                d->cp--;
                                d->row--;
                                if (d->row < 0)
                                        d->row += COL;  /* prev column ??? */
                        }
                        break;

                case 'J': /* Clear to end of display */
                        fillw(d->color|(' '<<8), d->cp, base + COL * ROW - d->cp);
                        break;

                case 'K': /* Clear to EOL */
                        fillw(d->color|(' '<<8), d->cp, COL - (d->cp - base) % COL);
                        break;

                case 'H': /* Cursor move */
                        if (d->cx > ROW)
                                d->cx = ROW;
                        if (d->cy > COL)
                                d->cy = COL;
                        if (d->cx == 0 || d->cy == 0) {
                                d->cp = base;
                                d->row = 0;
                        } else {
                                d->cp = base + (d->cx - 1) * COL + d->cy - 1;
                                d->row = d->cy - 1;
                        }
                        break;

                case '_': /* set cursor */
                        if (d->cx)
                                d->cx = 1;              /* block */
                        else
                                d->cx = 12;     /* underline */
                        outb(addr_6845, 10);
                        outb(addr_6845+1, d->cx);
                        outb(addr_6845, 11);
                        outb(addr_6845+1, 13);
                        break;

                case ';': /* Switch params in cursor def */
                        d->accp = &d->cy;
                        return;

                case '=': /* ESC[= color change */
                        d->state = EBRACEQ;
                        return;

                case 'L':       /* Insert line */
                        i = (d->cp - base) / COL;
                        /* avoid deficiency of bcopy implementation */
                        /* XXX: comment and hack relevant? */
                        pp = base + COL * (ROW-2);
                        for (j = ROW - 1 - i; j--; pp -= COL)
                                memmove(pp + COL, pp, COL * CHR);
                        fillw(d->color|(' '<<8), base + i * COL, COL);
                        break;

                case 'M':       /* Delete line */
                        i = (d->cp - base) / COL;
                        pp = base + i * COL;
                        memmove(pp, pp + COL, (ROW-1 - i)*COL*CHR);
                        fillw(d->color|(' '<<8), base + COL * (ROW - 1), COL);
                        break;

                default: /* Only numbers valid here */
                        if ((c >= '0') && (c <= '9')) {
                                *(d->accp) *= 10;
                                *(d->accp) += c - '0';
                                return;
                        } else
                                break;
                }
                d->state = NORMAL;
                break;

        case EBRACEQ: {
                /*
                 * In this state, the action at the end of the switch
                 * on the character type is to go to NORMAL state,
                 * and intermediate states do a return rather than break.
                 */
                u_char *colp;

                /*
                 * Set foreground/background color
                 * for normal mode, standout mode
                 * or kernel output.
                 * Based on code from kentp@svmp03.
                 */
                switch (c) {
                case 'F':
                        colp = ATTR_ADDR(d->color);
        do_fg:
                        *colp = (*colp & 0xf0) | (d->cx);
                        break;

                case 'G':
                        colp = ATTR_ADDR(d->color);
        do_bg:
                        *colp = (*colp & 0xf) | (d->cx << 4);
                        break;

                case 'H':
                        colp = ATTR_ADDR(d->color_so);
                        goto do_fg;

                case 'I':
                        colp = ATTR_ADDR(d->color_so);
                        goto do_bg;

                case 'S':
                        d->save_color = d->color;
                        d->save_color_so = d->color_so;
                        break;

                case 'R':
                        d->color = d->save_color;
                        d->color_so = d->save_color_so;
                        break;

                default: /* Only numbers valid here */
                        if ((c >= '0') && (c <= '9')) {
                                d->cx *= 10;
                                d->cx += c - '0';
                                return;
                        } else
                                break;
                }
                d->state = NORMAL;
            }
            break;

        case ESC:
                switch (c) {
                case 'c':       /* Clear screen & home */
                        fillw(d->color|(' '<<8), base, COL * ROW);
                        d->cp = base;
                        d->row = 0;
                        d->state = NORMAL;
                        break;
                case '[':       /* Start ESC [ sequence */
                        d->state = EBRAC;
                        d->cx = 0;
                        d->cy = 0;
                        d->accp = &d->cx;
                        break;
                default: /* Invalid, clear state */
                        d->state = NORMAL;
                        break;
                }
                break;
        }
        if (d->cp >= base + (COL * ROW)) { /* scroll check */
                memmove(base, base + COL, COL * (ROW - 1) * CHR);
                fillw(d->color|(' '<<8), base + COL * (ROW - 1), COL);
                d->cp -= COL;
        }       
        cursor();
}

void
vga_puts(char *s)
{
        char c;
        while ((c = *s++)) {
                vga_putc(c);
        }
}

void
video_on(void)
{

        /* Enable video */
        outb(0x3C4, 0x01);
        outb(0x3C5, inb(0x3C5) & ~0x20);
}

void
video_off(void)
{

        /* Disable video */
        outb(0x3C4, 0x01);
        outb(0x3C5, inb(0x3C5) | 0x20);
}

void
vga_init(u_char *ISA_mem)
{
        struct screen *d = &screen;

        memset(d, 0, sizeof (screen));
        video_on();

        d->cp = Crtat = (u_short *)&ISA_mem[0x0B8000];
        addr_6845 = CGA_BASE;
        initscreen();
        fillw(pccolor|(' '<<8), d->cp, COL * ROW);
}
#endif /* CONS_VGA */