sortix-mirror/kernel/vga.cpp

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/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2011, 2012.
This file is part of Sortix.
Sortix 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 3 of the License, or (at your option) any later
version.
Sortix 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
Sortix. If not, see <http://www.gnu.org/licenses/>.
vga.cpp
A Video Graphics Array driver.
*******************************************************************************/
#include <sortix/kernel/descriptor.h>
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#include <sortix/kernel/inode.h>
#include <sortix/kernel/interlock.h>
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#include <sortix/kernel/ioctx.h>
#include <sortix/kernel/kernel.h>
#include <sortix/kernel/kthread.h>
#include <sortix/kernel/process.h>
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#include <sortix/kernel/refcount.h>
#include <sortix/kernel/scheduler.h>
#include <sortix/kernel/syscall.h>
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#include <errno.h>
#include <string.h>
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#include "fs/util.h"
#include "vga.h"
#define TEST_VGAFONT 0
namespace Sortix {
namespace VGA {
uint8_t* const VGA = (uint8_t* const) 0xB8000;
const unsigned WIDTH = 80;
const unsigned HEIGHT = 25;
const size_t VGA_SIZE = sizeof(uint16_t) * WIDTH * HEIGHT;
size_t vgafontsize;
uint8_t* vgafont;
static void WriteIndex(uint16_t port, uint8_t index, uint8_t value)
{
CPU::OutPortB(port, index);
CPU::OutPortB(port+1, value);
}
static uint8_t ReadIndex(uint16_t port, uint8_t index)
{
CPU::OutPortB(port, index);
return CPU::InPortB(port+1);
}
static uint8_t ReplaceIndex(uint16_t port, uint8_t index, uint8_t value)
{
uint8_t ret = ReadIndex(port, index);
WriteIndex(port, index, value);
return ret;
}
static void FetchVGAFont(uint8_t* font)
{
// TODO: I just got these magic constants off the net.
// Select plane 2 for reading.
uint8_t old_03ce_04 = ReplaceIndex(0x03CE, 0x04, 0x02);
// Clear even/odd mode.
uint8_t old_03ce_05 = ReplaceIndex(0x03CE, 0x05, 0x04);
// Map VGA Memory to 0xA0000 (Select 0xA0000-0xAFFFF).
uint8_t old_03ce_06 = ReplaceIndex(0x03CE, 0x06, 0x04);
// Set bitplane 2.
uint8_t old_03c4_02 = ReplaceIndex(0x03C4, 0x02, 0x04);
// Clear even/odd mode (the other way, don't ask why).
uint8_t old_03c4_04 = ReplaceIndex(0x03C4, 0x04, 0x07);
// The font data is now at 0xA0000, so fetch it. Note that there is
// reserved room for a 8x32 resolution but we are using 8x16.
const uint8_t* data = (const uint8_t*) 0xA0000UL;
for ( size_t i = 0; i < VGA_FONT_NUMCHARS; i++ )
{
const uint8_t* src = data + (32*8)/8 * i;
uint8_t* dest = font + VGA_FONT_CHARSIZE * i;
memcpy(dest, src, VGA_FONT_CHARSIZE);
}
// Restore the VGA state.
WriteIndex(0x03C4, 0x02, old_03c4_02);
WriteIndex(0x03C4, 0x04, old_03c4_04);
WriteIndex(0x03CE, 0x05, old_03ce_05);
WriteIndex(0x03CE, 0x06, old_03ce_06);
WriteIndex(0x03CE, 0x04, old_03ce_04);
}
#if TEST_VGAFONT
static void PrintFontChar(const uint8_t* font, unsigned char c)
{
const uint8_t* glyph = font + VGA_FONT_CHARSIZE * (size_t) c;
for ( size_t y = 0; y < VGA_FONT_HEIGHT; y++ )
{
for ( size_t x = 0; x < VGA_FONT_WIDTH; x++ )
{
size_t bitindex = y * VGA_FONT_WIDTH + x;
uint8_t bitmap = glyph[bitindex/8UL];
uint8_t bitmod = bitindex % 8UL;
uint8_t bitmask = 1U << bitmod;
const char* toprint = (bitmap & bitmask) ? "X" : " ";
Log::Print(toprint);
}
Log::Print("\n");
}
}
#endif
const uint8_t* GetFont()
{
return vgafont;
}
void Init(const char* devpath, Ref<Descriptor> slashdev)
{
vgafontsize = VGA_FONT_NUMCHARS * VGA_FONT_CHARSIZE;
if ( !(vgafont = new uint8_t[vgafontsize]) )
Panic("Unable to allocate vga font buffer");
FetchVGAFont(vgafont);
#if TEST_VGAFONT
PrintFontChar(vgafont, 'A');
PrintFontChar(vgafont, 'S');
#endif
ioctx_t ctx; SetupKernelIOCtx(&ctx);
// Setup the vgafont device.
Ref<Inode> vgafontnode(new UtilMemoryBuffer(slashdev->dev, (ino_t) 0, 0, 0,
0660, vgafont, vgafontsize,
false, false));
if ( !vgafontnode )
PanicF("Unable to allocate %s/vgafont inode.", devpath);
if ( LinkInodeInDir(&ctx, slashdev, "vgafont", vgafontnode) != 0 )
PanicF("Unable to link %s/vgafont to vga font.", devpath);
// Setup the vga device.
Ref<Inode> vganode(new UtilMemoryBuffer(slashdev->dev, (ino_t) 0, 0, 0,
0660, VGA, VGA_SIZE, true, false));
if ( !vganode )
PanicF("Unable to allocate %s/vga inode.", devpath);
if ( LinkInodeInDir(&ctx, slashdev, "vga", vganode) != 0 )
PanicF("Unable to link %s/vga to vga.", devpath);
}
// Changes the position of the hardware cursor.
void SetCursor(unsigned x, unsigned y)
{
unsigned value = x + y * WIDTH;
// This sends a command to indicies 14 and 15 in the
// CRT Control Register of the VGA controller. These
// are the high and low bytes of the index that show
// where the hardware cursor is to be 'blinking'.
CPU::OutPortB(0x3D4, 14);
CPU::OutPortB(0x3D5, (value >> 8) & 0xFF);
CPU::OutPortB(0x3D4, 15);
CPU::OutPortB(0x3D5, (value >> 0) & 0xFF);
}
} // namespace VGA
} // namespace Sortix