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/*

 *  This file contains the TTY driver for VGA

 *

 *  COPYRIGHT (c) 1998 by Radstone Technology

 *

 *

 * THIS FILE IS PROVIDED TO YOU, THE USER, "AS IS", WITHOUT WARRANTY OF ANY

 * KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK

 * AS TO THE QUALITY AND PERFORMANCE OF ALL CODE IN THIS FILE IS WITH YOU.

 *

 * You are hereby granted permission to use, copy, modify, and distribute

 * this file, provided that this notice, plus the above copyright notice

 * and disclaimer, appears in all copies. Radstone Technology will provide

 * no support for this code.

 *

 *  This driver uses the termios pseudo driver.

 */

/*-------------------------------------------------------------------------+

| (C) Copyright 1997 -

| - NavIST Group - Real-Time Distributed Systems and Industrial Automation

|

| http://pandora.ist.utl.pt

|

| Instituto Superior Tecnico * Lisboa * PORTUGAL

+--------------------------------------------------------------------------+

| Disclaimer:

|

| This file is provided "AS IS" without warranty of any kind, either

| expressed or implied.

+--------------------------------------------------------------------------+

| This code is based on:

|   outch.c,v 1.4 1995/12/19 20:07:27 joel Exp - go32 BSP

| With the following copyright notice:

| **************************************************************************

| * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994.                      *

| * On-Line Applications Research Corporation (OAR).                       *

| * All rights assigned to U.S. Government, 1994.                          *

| *                                                                        *

| * This material may be reproduced by or for the U.S. Government pursuant *

| * to the copyright license under the clause at DFARS 252.227-7013.  This *

| * notice must appear in all copies of this file and its derivatives.     *

| **************************************************************************

+--------------------------------------------------------------------------*/

#include <bsp.h>

#include <stdlib.h>

#include <string.h>

#include "vga_p.h"

/*-------------------------------------------------------------------------+

| Constants

+--------------------------------------------------------------------------*/

#define DISPLAY_CELL_COUNT (VGA_NUM_ROWS * VGA_NUM_COLS)

                                       /* Number of display cells.            */

#define TABSIZE 4                      /* Number of spaces for TAB (\t) char. */

#define WHITE   0x0007                 /* White on Black background colour.   */

#define BLANK   (WHITE | (' '<<8))     /* Blank character.                    */

/*

 * This is imported from i8042.c to provide flow control

 */

extern volatile boolean bScrollLock;

/*-------------------------------------------------------------------------+

| Global Variables

+--------------------------------------------------------------------------*/

/* Physical address of start of video text memory. */

static unsigned16 *videoRam    = (unsigned16 *)VGA_FB;

/* Pointer for current output position in display. */

static unsigned16 *videoRamPtr = (unsigned16 *)VGA_FB;

static unsigned8  videoRows = VGA_NUM_ROWS; /* Number of rows in display.    */

static unsigned8  videoCols = VGA_NUM_COLS; /* Number of columns in display. */

static unsigned8  cursRow   = 0;       /* Current cursor row.           */

static unsigned8  cursCol   = 0;       /* Current cursor column.        */

/*-------------------------------------------------------------------------+

|         Function: setHardwareCursorPos

|      Description: Set hardware video cursor at given offset into video RAM.

| Global Variables: None.

|        Arguments: videoCursor - Offset into video memory.

|          Returns: Nothing.

+--------------------------------------------------------------------------*/

static inline void

setHardwareCursorPos(unsigned16 videoCursor)

{

        VGA_WRITE_CRTC(0x0e, (videoCursor >> 8) & 0xff);

        VGA_WRITE_CRTC(0x0f, videoCursor & 0xff);

} /* setHardwareCursorPos */

/*-------------------------------------------------------------------------+

|         Function: updateVideoRamPtr

|      Description: Updates value of global variable "videoRamPtr" based on

|                   current window's cursor position.

| Global Variables: videoRamPtr, cursRow, cursCol.

|        Arguments: None.

|          Returns: Nothing.

+--------------------------------------------------------------------------*/

static inline void

updateVideoRamPtr(void)

{

        videoRamPtr = videoRam + cursRow * videoCols + cursCol;

} /* updateVideoRamPtr */

/*-------------------------------------------------------------------------+

|         Function: scrollUp

|      Description: Scrolls display up n lines.

| Global Variables: None.

|        Arguments: lines - number of lines to scroll.

|          Returns: Nothing.

+--------------------------------------------------------------------------*/

static void

scrollUp(unsigned8 lines)

{

        /* Number of blank display cells on bottom of window. */

        unsigned16 blankCount;

       /* Source and destination pointers for memory copy operations. */

        unsigned16 *ptrDst, *ptrSrc;

        if(lines<videoRows)  /* Move window's contents up. */

        {

                /*

                 * Number of non-blank cells on upper part

                 * of display (total - blank).

                 */

                unsigned16 nonBlankCount;

                blankCount = lines * videoCols;

                nonBlankCount = DISPLAY_CELL_COUNT - blankCount;

                ptrSrc = videoRam + blankCount;

                ptrDst = videoRam;

                while(nonBlankCount--)

                {

                        *ptrDst++ = *ptrSrc++;

                }

        }

        else

        {

                /*

                 * Clear the whole display.

                 */

                blankCount = DISPLAY_CELL_COUNT;

                ptrDst = videoRam;

        }

        /* Fill bottom with blanks. */

        while (blankCount-->0)

        {

                *ptrDst++ = BLANK;

        }

} /* scrollUp */

/*-------------------------------------------------------------------------+

|         Function: printCHAR

|      Description: Print printable character to display.

| Global Variables: videoRamPtr, cursRow, cursCol.

|        Arguments: c - character to write to display.

|          Returns: Nothing.

+--------------------------------------------------------------------------*/

static void

printCHAR(char c)

{

        *videoRamPtr++ = (c<<8) | WHITE;

        cursCol++;

        if(cursCol==videoCols)

        {

                cursCol = 0;

                cursRow++;

                if(cursRow==videoRows)

                {

                        cursRow--;

                        scrollUp(1);

                        videoRamPtr -= videoCols;

                }

        }

} /* printCHAR */

/*-------------------------------------------------------------------------+

|         Function: printBS

|      Description: Print BS (BackSpace - '\b') character to display.

| Global Variables: videoRamPtr, cursRow, cursCol.

|        Arguments: None.

|          Returns: Nothing.

+--------------------------------------------------------------------------*/

static inline void

printBS(void)

{

        /* Move cursor back one cell. */

        if(cursCol>0)

        {

                cursCol--;

        }

        else if(cursRow>0)

        {

                cursRow--;

                cursCol = videoCols - 1;

        }

        else

        {

                return;

        }

        /* Write a whitespace. */

        *(--videoRamPtr) = BLANK;

} /* printBS */

/*-------------------------------------------------------------------------+

|         Function: printHT

|      Description: Print HT (Horizontal Tab - '\t') character to display.

| Global Variables: cursCol.

|        Arguments: None.

|          Returns: Nothing.

+--------------------------------------------------------------------------*/

static inline void

printHT(void)

{

        do

        {

                printCHAR(' ');

        }

        while (cursCol % TABSIZE);

} /* printHT */

/*-------------------------------------------------------------------------+

|         Function: printLF

|      Description: Print LF (Line Feed  - '\n') character to display.

| Global Variables: cursRow.

|        Arguments: None.

|          Returns: Nothing.

+--------------------------------------------------------------------------*/

static inline void

printLF(void)

{

        cursRow++;

        if(cursRow==videoRows)

        {

                cursRow--;

                scrollUp(1);

        }

        updateVideoRamPtr();

} /* printLF */

/*-------------------------------------------------------------------------+

|         Function: printCR

|      Description: Print CR (Carriage Return - '\r') to display.

| Global Variables: cursCol.

|        Arguments: None.

|          Returns: Nothing.

+--------------------------------------------------------------------------*/

static inline void

printCR(void)

{

        cursCol = 0;

        updateVideoRamPtr();

} /* printCR */

/*

 *  Console Device Driver Entry Points

 */

void

vga_write(

        int   minor,

        char cChar)

{

        switch (cChar)

        {

                case '\b':

                        printBS();

                        break;

                case '\t':

                        printHT();

                        break;

                case '\n':

                        printLF();

                        break;

                case '\r':

                        printCR();

                        break;

                default:

                        printCHAR(cChar);

                        break;

        }

        setHardwareCursorPos(videoRamPtr - videoRam);

} /* vga_write */

/*

 *  vga_write_support

 *

 *  Console Termios output entry point.

 *

 */

int vga_write_support(

        int   minor,

        const char *buf,

        int   len

)

{

        int nwrite = 0;

        while(bScrollLock)

        {

                /*

                 * The Scroll lock on the keyboard is active

                 */

                /*

                 * Yield while we wait

                 */

                rtems_task_wake_after(RTEMS_YIELD_PROCESSOR);

        }

        /*

         * Write each byte in the string to the display

         */

        while (nwrite<len)

        {

                /*

                 * transmit character

                 */

                vga_write(minor, *buf++);

                nwrite++;

        }

        /*

         * return the number of bytes written.

         */

        return nwrite;

}

boolean vga_probe(int minor)

{

        unsigned8 ucMiscIn;

        /*

         * Check for presence of VGA adaptor

         */

        inport_byte(0x3cc, ucMiscIn);

        if(ucMiscIn!=0xff)

        {

                /*

                 * VGA device is present

                 */

                return(TRUE);

        }

        return(FALSE);

}

void vga_init(int minor)

{

        scrollUp(videoRows);     /* Clear entire screen         */

        setHardwareCursorPos(0); /* Cursor at upper left corner */

        /*

         * Enable the cursor

         */

        VGA_WRITE_CRTC(0x0a, 0x0e);     /* Crt cursor start */

}