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#include "vga.h"
#include "stdio.h"
#include "kernel.h"
#undef DEBUG
static vga_vtable_t vga_vtable = {
{
vga_activate,
vga_deactivate,
vga_deinit,
vga_print_info
}
};
void vga_init( vga_t *vga, void *context )
{
memset( vga, 0, sizeof( vga_t ) );
port8_init( &vga->misc_port, 0x3C2 );
port8_init( &vga->crtc_index_port, 0x3D4 );
port8_init( &vga->crtc_data_port, 0x3D5 );
port8_init( &vga->sequencer_index_port, 0x3C4 );
port8_init( &vga->sequencer_data_port, 0x3C5 );
port8_init( &vga->graphics_controller_index_port, 0x3CE );
port8_init( &vga->graphics_controller_data_port, 0x3CF );
port8_init( &vga->attribute_controller_index_port, 0x3C0 );
port8_init( &vga->attribute_controller_read_port, 0x3C1 );
port8_init( &vga->attribute_controller_write_port, 0x3C0 );
port8_init( &vga->attribute_controller_reset_port, 0x3DA );
vga->context = context;
vga->base.vtable = &vga_vtable.base;
}
void vga_activate( void *obj )
{
puts( "Activating driver for VGA video card.." );
}
void vga_deactivate( void *obj )
{
puts( "Dectivating driver for VGA video card.." );
}
void vga_deinit( void *obj )
{
// nothing to do
}
void vga_print_info( void *obj )
{
puts( "Generic VGA video driver" );
}
static void write_registers( vga_t *vga, uint8_t *regs )
{
// misc
port8_write( &vga->misc_port, *( regs++ ) );
// seq (5)
for( uint8_t i = 0; i < 5; i++ ) {
port8_write( &vga->sequencer_index_port, i );
port8_write( &vga->sequencer_data_port, *( regs++ ) );
}
// unlock CRTC register (and make sure mode data doesn't lock it again by accident)
port8_write( &vga->crtc_index_port, 0x03 );
port8_write( &vga->crtc_data_port, port8_read( &vga->crtc_data_port ) | 0x80 );
port8_write( &vga->crtc_index_port, 0x11 );
port8_write( &vga->crtc_data_port, port8_read( &vga->crtc_data_port ) & ~0x80 );
regs[0x3] |= 0x80;
regs[0x11] &= ~0x80;
// crtc (25)
for( uint8_t i = 0; i < 25; i++ ) {
port8_write( &vga->crtc_index_port, i );
port8_write( &vga->crtc_data_port, *( regs++ ) );
}
// gc (9)
for( uint8_t i = 0; i < 9; i++ ) {
port8_write( &vga->graphics_controller_index_port, i );
port8_write( &vga->graphics_controller_data_port, *( regs++ ) );
}
// ac (21)
for( uint8_t i = 0; i < 21; i++ ) {
(void)port8_read( &vga->attribute_controller_reset_port );
port8_write( &vga->attribute_controller_index_port, i );
port8_write( &vga->attribute_controller_write_port, *( regs++ ) );
}
// lock 16-color palette and unblank display
(void)port8_read( &vga->attribute_controller_reset_port );
port8_write( &vga->attribute_controller_index_port, 0x20 );
}
vga_mode_t vga_make_mode( const int x, const int y, const int color_depth )
{
vga_mode_t mode;
mode.x = x;
mode.y = y;
mode.color_depth = color_depth;
return mode;
}
static vga_mode_t modes[] = {
{ 320, 200, 8,
// from http://files.osdev.org/mirrors/geezer/osd/graphics/modes.c
{
/* MISC */
0x63,
/* SEQ */
0x03, 0x01, 0x0F, 0x00, 0x0E,
/* CRTC */
0x5F, 0x4F, 0x50, 0x82, 0x54, 0x80, 0xBF, 0x1F,
0x00, 0x41, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x9C, 0x0E, 0x8F, 0x28, 0x40, 0x96, 0xB9, 0xA3,
0xFF,
/* GC */
0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x05, 0x0F,
0xFF,
/* AC */
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
0x41, 0x00, 0x0F, 0x00, 0x00
}
}
};
bool vga_supports_mode( const vga_mode_t mode )
{
for( int i = 0; modes[i].x != 0; i++ ) {
if( mode.x == modes[i].x &&
mode.y == modes[i].y &&
mode.color_depth == modes[i].color_depth ) {
return true;
}
}
return false;
}
static int get_matching_mode_idx( const vga_mode_t mode )
{
for( int i = 0; modes[i].x != 0; i++ ) {
if( mode.x == modes[i].x &&
mode.y == modes[i].y &&
mode.color_depth == modes[i].color_depth ) {
return i;
}
}
return -1;
}
bool vga_set_mode( vga_t *vga, const vga_mode_t mode )
{
// do not allow unknown timings!
if( !vga_supports_mode( mode ) ) {
return false;
}
vga_mode_t matching_mode = modes[get_matching_mode_idx( mode )];
write_registers( vga, matching_mode.regs );
vga->mode = mode;
return true;
}
vga_color_t vga_make_RGB( int R, int G, int B )
{
vga_color_t c;
c.R = R;
c.G = G;
c.B = B;
return c;
}
static uint8_t *get_frame_buffer_segment( vga_t *vga )
{
port8_write( &vga->graphics_controller_index_port, 0x06 );
uint8_t segment_no = ( port8_read( &vga->graphics_controller_data_port ) >> 2 ) & 0x03;
uint8_t *segment;
switch( segment_no ) {
case 0: // A0000h - BFFFFh, 128k
segment = (uint8_t *)0xA0000;
break;
case 1: // A0000h - AFFFFh, 64k
segment = (uint8_t *)0xA0000;
break;
case 2: // B0000h - B7FFFh, 32k
segment = (uint8_t *)0xB0000;
break;
case 3: // B8000h - BFFFFh, 32k
segment = (uint8_t *)0xB8000;
break;
}
#ifdef DEBUG
printf( "segment: %d 0x%X\n", segment_no, segment );
#endif
return segment;
}
static uint8_t get_color_index( const vga_color_t c )
{
// TODO: for now white and black, standard VGA palette entries?
if( c.R == 0x00 && c.G == 0x00 && c.B == 0x00 ) return 0x00;
if( c.R == 0x00 && c.G == 0x00 && c.B == 0xA8 ) return 0x01;
if( c.R == 0xFF && c.G == 0xFF && c.B == 0xFF ) return 0x3F;
return 0x00;
}
static bool params_ok( vga_t *vga, const int x, const int y )
{
if( x < 0 || x > vga->mode.x || y < 0 || y > vga->mode.y ) {
return false;
}
return true;
}
void vga_set_pixel( vga_t *vga, const int x, const int y, const vga_color_t color )
{
if( !params_ok( vga, x, y ) ) {
kernel_panic( "Pixel coordinates are out of bounds: (%d, %d), resolution is only (%d, %d)",
x, y, vga->mode.x, vga->mode.y );
}
uint8_t color_idx = get_color_index( color );
uint8_t *segment = get_frame_buffer_segment( vga );
uint8_t *addr = segment + vga->mode.x * y + x;
// printf( "%d %d 0x%X, 0x%X 0x%X\n", x, y, segment, addr, color_idx );
*addr = color_idx;
}
void vga_draw_rectangle( vga_t *vga, const int x, const int y, const int w, const int h, const vga_color_t color )
{
for( int yy = y; yy < y + h; yy++ ) {
for( int xx = x; xx < x + w; xx++ ) {
vga_set_pixel( vga, xx, yy, color );
}
}
}
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