bios_console.c

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/*
 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

FILE_LICENCE ( GPL2_OR_LATER );

#include <assert.h>
#include <realmode.h>
#include <console.h>
#include <gpxe/ansiesc.h>

#define ATTR_BOLD               0x08

#define ATTR_FCOL_MASK          0x07
#define ATTR_FCOL_BLACK         0x00
#define ATTR_FCOL_BLUE          0x01
#define ATTR_FCOL_GREEN         0x02
#define ATTR_FCOL_CYAN          0x03
#define ATTR_FCOL_RED           0x04
#define ATTR_FCOL_MAGENTA       0x05
#define ATTR_FCOL_YELLOW        0x06
#define ATTR_FCOL_WHITE         0x07

#define ATTR_BCOL_MASK          0x70
#define ATTR_BCOL_BLACK         0x00
#define ATTR_BCOL_BLUE          0x10
#define ATTR_BCOL_GREEN         0x20
#define ATTR_BCOL_CYAN          0x30
#define ATTR_BCOL_RED           0x40
#define ATTR_BCOL_MAGENTA       0x50
#define ATTR_BCOL_YELLOW        0x60
#define ATTR_BCOL_WHITE         0x70

#define ATTR_DEFAULT            ATTR_FCOL_WHITE

/** Current character attribute */
static unsigned int bios_attr = ATTR_DEFAULT;

/**
 * Handle ANSI CUP (cursor position)
 *
 * @v count             Parameter count
 * @v params[0]         Row (1 is top)
 * @v params[1]         Column (1 is left)
 */
static void bios_handle_cup ( unsigned int count __unused, int params[] ) {
        int cx = ( params[1] - 1 );
        int cy = ( params[0] - 1 );

        if ( cx < 0 )
                cx = 0;
        if ( cy < 0 )
                cy = 0;

        __asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
                                           "int $0x10\n\t"
                                           "cli\n\t" )
                               : : "a" ( 0x0200 ), "b" ( 1 ),
                                   "d" ( ( cy << 8 ) | cx ) );
}

/**
 * Handle ANSI ED (erase in page)
 *
 * @v count             Parameter count
 * @v params[0]         Region to erase
 */
static void bios_handle_ed ( unsigned int count __unused,
                             int params[] __unused ) {
        /* We assume that we always clear the whole screen */
        assert ( params[0] == ANSIESC_ED_ALL );

        __asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
                                           "int $0x10\n\t"
                                           "cli\n\t" )
                               : : "a" ( 0x0600 ), "b" ( bios_attr << 8 ),
                                   "c" ( 0 ), "d" ( 0xffff ) );
}

/**
 * Handle ANSI SGR (set graphics rendition)
 *
 * @v count             Parameter count
 * @v params            List of graphic rendition aspects
 */
static void bios_handle_sgr ( unsigned int count, int params[] ) {
        static const uint8_t bios_attr_fcols[10] = {
                ATTR_FCOL_BLACK, ATTR_FCOL_RED, ATTR_FCOL_GREEN,
                ATTR_FCOL_YELLOW, ATTR_FCOL_BLUE, ATTR_FCOL_MAGENTA,
                ATTR_FCOL_CYAN, ATTR_FCOL_WHITE,
                ATTR_FCOL_WHITE, ATTR_FCOL_WHITE /* defaults */
        };
        static const uint8_t bios_attr_bcols[10] = {
                ATTR_BCOL_BLACK, ATTR_BCOL_RED, ATTR_BCOL_GREEN,
                ATTR_BCOL_YELLOW, ATTR_BCOL_BLUE, ATTR_BCOL_MAGENTA,
                ATTR_BCOL_CYAN, ATTR_BCOL_WHITE,
                ATTR_BCOL_BLACK, ATTR_BCOL_BLACK /* defaults */
        };
        unsigned int i;
        int aspect;

        for ( i = 0 ; i < count ; i++ ) {
                aspect = params[i];
                if ( aspect == 0 ) {
                        bios_attr = ATTR_DEFAULT;
                } else if ( aspect == 1 ) {
                        bios_attr |= ATTR_BOLD;
                } else if ( aspect == 22 ) {
                        bios_attr &= ~ATTR_BOLD;
                } else if ( ( aspect >= 30 ) && ( aspect <= 39 ) ) {
                        bios_attr &= ~ATTR_FCOL_MASK;
                        bios_attr |= bios_attr_fcols[ aspect - 30 ];
                } else if ( ( aspect >= 40 ) && ( aspect <= 49 ) ) {
                        bios_attr &= ~ATTR_BCOL_MASK;
                        bios_attr |= bios_attr_bcols[ aspect - 40 ];
                }
        }
}

/** BIOS console ANSI escape sequence handlers */
static struct ansiesc_handler bios_ansiesc_handlers[] = {
        { ANSIESC_CUP, bios_handle_cup },
        { ANSIESC_ED, bios_handle_ed },
        { ANSIESC_SGR, bios_handle_sgr },
        { 0, NULL }
};

/** BIOS console ANSI escape sequence context */
static struct ansiesc_context bios_ansiesc_ctx = {
        .handlers = bios_ansiesc_handlers,
};

/**
 * Print a character to BIOS console
 *
 * @v character         Character to be printed
 */
static void bios_putchar ( int character ) {
        int discard_a, discard_b, discard_c;

        /* Intercept ANSI escape sequences */
        character = ansiesc_process ( &bios_ansiesc_ctx, character );
        if ( character < 0 )
                return;

        /* Print character with attribute */
        __asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
                                           /* Skip non-printable characters */
                                           "cmpb $0x20, %%al\n\t"
                                           "jb 1f\n\t"
                                           /* Set attribute */
                                           "movw $0x0001, %%cx\n\t"
                                           "movb $0x09, %%ah\n\t"
                                           "int $0x10\n\t"
                                           "\n1:\n\t"
                                           /* Print character */
                                           "xorw %%bx, %%bx\n\t"
                                           "movb $0x0e, %%ah\n\t"
                                           "int $0x10\n\t"
                                           "cli\n\t" )
                               : "=a" ( discard_a ), "=b" ( discard_b ),
                                 "=c" ( discard_c )
                               : "a" ( character ), "b" ( bios_attr )
                               : "ebp" );
}

/**
 * Pointer to current ANSI output sequence
 *
 * While we are in the middle of returning an ANSI sequence for a
 * special key, this will point to the next character to return.  When
 * not in the middle of such a sequence, this will point to a NUL
 * (note: not "will be NULL").
 */
static const char *ansi_input = "";

/**
 * Lowest BIOS scancode of interest
 *
 * Most of the BIOS key scancodes that we are interested in are in a
 * dense range, so subtracting a constant and treating them as offsets
 * into an array works efficiently.
 */
#define BIOS_KEY_MIN 0x42

/** Offset into list of interesting BIOS scancodes */
#define BIOS_KEY(scancode) ( (scancode) - BIOS_KEY_MIN )

/** Mapping from BIOS scan codes to ANSI escape sequences */
static const char *ansi_sequences[] = {
        [ BIOS_KEY ( 0x42 ) ] = "[19~", /* F8 (required for PXE) */
        [ BIOS_KEY ( 0x47 ) ] = "[H",   /* Home */
        [ BIOS_KEY ( 0x48 ) ] = "[A",   /* Up arrow */
        [ BIOS_KEY ( 0x4b ) ] = "[D",   /* Left arrow */
        [ BIOS_KEY ( 0x4d ) ] = "[C",   /* Right arrow */
        [ BIOS_KEY ( 0x4f ) ] = "[F",   /* End */
        [ BIOS_KEY ( 0x50 ) ] = "[B",   /* Down arrow */
        [ BIOS_KEY ( 0x53 ) ] = "[3~",  /* Delete */
};

/**
 * Get ANSI escape sequence corresponding to BIOS scancode
 *
 * @v scancode          BIOS scancode
 * @ret ansi_seq        ANSI escape sequence, if any, otherwise NULL
 */
static const char * scancode_to_ansi_seq ( unsigned int scancode ) {
        unsigned int bios_key = BIOS_KEY ( scancode );
        
        if ( bios_key < ( sizeof ( ansi_sequences ) /
                          sizeof ( ansi_sequences[0] ) ) ) {
                return ansi_sequences[bios_key];
        }
        DBG ( "Unrecognised BIOS scancode %02x\n", scancode );
        return NULL;
}

/**
 * Get character from BIOS console
 *
 * @ret character       Character read from console
 */
static int bios_getchar ( void ) {
        uint16_t keypress;
        unsigned int character;
        const char *ansi_seq;

        /* If we are mid-sequence, pass out the next byte */
        if ( ( character = *ansi_input ) ) {
                ansi_input++;
                return character;
        }

        /* Read character from real BIOS console */
        __asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
                                           "int $0x16\n\t"
                                           "cli\n\t" )
                               : "=a" ( keypress ) : "a" ( 0x1000 ) );
        character = ( keypress & 0xff );

        /* If it's a normal character, just return it */
        if ( character && ( character < 0x80 ) )
                return character;

        /* Otherwise, check for a special key that we know about */
        if ( ( ansi_seq = scancode_to_ansi_seq ( keypress >> 8 ) ) ) {
                /* Start of escape sequence: return ESC (0x1b) */
                ansi_input = ansi_seq;
                return 0x1b;
        }

        return 0;
}

/**
 * Check for character ready to read from BIOS console
 *
 * @ret True            Character available to read
 * @ret False           No character available to read
 */
static int bios_iskey ( void ) {
        unsigned int discard_a;
        unsigned int flags;

        /* If we are mid-sequence, we are always ready */
        if ( *ansi_input )
                return 1;

        /* Otherwise check the real BIOS console */
        __asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
                                           "int $0x16\n\t"
                                           "pushfw\n\t"
                                           "popw %w0\n\t"
                                           "cli\n\t" )
                               : "=r" ( flags ), "=a" ( discard_a )
                               : "a" ( 0x0100 ) );
        return ( ! ( flags & ZF ) );
}

struct console_driver bios_console __console_driver = {
        .putchar = bios_putchar,
        .getchar = bios_getchar,
        .iskey = bios_iskey,
};