235 lines
6.1 KiB
C++
235 lines
6.1 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2012.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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Sortix. If not, see <http://www.gnu.org/licenses/>.
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vga.cpp
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A Video Graphics Array driver.
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*******************************************************************************/
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#include <sortix/kernel/platform.h>
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#include <errno.h>
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#include <string.h>
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#include "fs/util.h"
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#include "fs/devfs.h"
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#include "vga.h"
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#include "scheduler.h"
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#include "syscall.h"
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#include "process.h"
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#include "serialterminal.h"
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#define TEST_VGAFONT 0
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namespace Sortix {
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namespace VGA {
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uint8_t* const VGA = (uint8_t* const) 0xB8000;
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const unsigned WIDTH = 80;
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const unsigned HEIGHT = 25;
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const size_t VGA_SIZE = sizeof(uint16_t) * WIDTH * HEIGHT;
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size_t vgafontsize;
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uint8_t* vgafont;
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static void WriteIndex(uint16_t port, uint8_t index, uint8_t value)
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{
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CPU::OutPortB(port, index);
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CPU::OutPortB(port+1, value);
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}
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static uint8_t ReadIndex(uint16_t port, uint8_t index)
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{
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CPU::OutPortB(port, index);
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return CPU::InPortB(port+1);
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}
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static uint8_t ReplaceIndex(uint16_t port, uint8_t index, uint8_t value)
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{
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uint8_t ret = ReadIndex(port, index);
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WriteIndex(port, index, value);
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return ret;
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}
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static void FetchVGAFont(uint8_t* font)
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{
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// TODO: I just got these magic constants off the net.
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// Select plane 2 for reading.
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uint8_t old_03ce_04 = ReplaceIndex(0x03CE, 0x04, 0x02);
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// Clear even/odd mode.
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uint8_t old_03ce_05 = ReplaceIndex(0x03CE, 0x05, 0x04);
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// Map VGA Memory to 0xA0000 (Select 0xA0000-0xAFFFF).
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uint8_t old_03ce_06 = ReplaceIndex(0x03CE, 0x06, 0x04);
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// Set bitplane 2.
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uint8_t old_03c4_02 = ReplaceIndex(0x03C4, 0x02, 0x04);
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// Clear even/odd mode (the other way, don't ask why).
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uint8_t old_03c4_04 = ReplaceIndex(0x03C4, 0x04, 0x07);
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// The font data is now at 0xA0000, so fetch it. Note that there is
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// reserved room for a 8x32 resolution but we are using 8x16.
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const uint8_t* data = (const uint8_t*) 0xA0000UL;
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for ( size_t i = 0; i < VGA_FONT_NUMCHARS; i++ )
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{
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const uint8_t* src = data + (32*8)/8 * i;
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uint8_t* dest = font + VGA_FONT_CHARSIZE * i;
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memcpy(dest, src, VGA_FONT_CHARSIZE);
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}
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// Restore the VGA state.
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WriteIndex(0x03C4, 0x02, old_03c4_02);
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WriteIndex(0x03C4, 0x04, old_03c4_04);
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WriteIndex(0x03CE, 0x05, old_03ce_05);
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WriteIndex(0x03CE, 0x06, old_03ce_06);
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WriteIndex(0x03CE, 0x04, old_03ce_04);
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}
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#if TEST_VGAFONT
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static void PrintFontChar(const uint8_t* font, unsigned char c)
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{
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const uint8_t* glyph = font + VGA_FONT_CHARSIZE * (size_t) c;
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for ( size_t y = 0; y < VGA_FONT_HEIGHT; y++ )
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{
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for ( size_t x = 0; x < VGA_FONT_WIDTH; x++ )
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{
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size_t bitindex = y * VGA_FONT_WIDTH + x;
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uint8_t bitmap = glyph[bitindex/8UL];
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uint8_t bitmod = bitindex % 8UL;
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uint8_t bitmask = 1U << bitmod;
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const char* toprint = (bitmap & bitmask) ? "X" : " ";
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Log::Print(toprint);
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}
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Log::Print("\n");
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}
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}
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#endif
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const uint8_t* GetFont()
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{
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return vgafont;
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}
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void Init()
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{
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vgafontsize = VGA_FONT_NUMCHARS * VGA_FONT_CHARSIZE;
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if ( !(vgafont = new uint8_t[vgafontsize]) )
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Panic("Unable to allocate vga font buffer");
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FetchVGAFont(vgafont);
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#if TEST_VGAFONT
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PrintFontChar(vgafont, 'A');
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PrintFontChar(vgafont, 'S');
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#endif
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DevMemoryBuffer* vgamembuf = new DevMemoryBuffer(vgafont, vgafontsize,
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false, false);
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if ( !vgamembuf )
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Panic("Unable to allocate vga font filesystem object");
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if ( !DeviceFS::RegisterDevice("vgafont", vgamembuf) )
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Panic("Unable to register vga font filesystem object");
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}
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// Changes the position of the hardware cursor.
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void SetCursor(unsigned x, unsigned y)
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{
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unsigned value = x + y * WIDTH;
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// This sends a command to indicies 14 and 15 in the
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// CRT Control Register of the VGA controller. These
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// are the high and low bytes of the index that show
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// where the hardware cursor is to be 'blinking'.
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CPU::OutPortB(0x3D4, 14);
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CPU::OutPortB(0x3D5, (value >> 8) & 0xFF);
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CPU::OutPortB(0x3D4, 15);
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CPU::OutPortB(0x3D5, (value >> 0) & 0xFF);
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}
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} // namespace VGA
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DevVGA::DevVGA()
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{
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offset = 0;
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}
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DevVGA::~DevVGA()
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{
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#ifdef PLATFORM_SERIAL
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// TODO: HACK: This is a hack that is unrelated to this file.
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// This is a hack to make the cursor a proper color after the vga buffer
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// has been radically modified. The best solution would be for the VGA
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// to ANSI Escape Codes converter to keep track of colors and restoring
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// them, but this will do for now.
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Log::PrintF("\e[m");
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#endif
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}
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ssize_t DevVGA::Read(uint8_t* dest, size_t count)
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{
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if ( VGA::VGA_SIZE - offset < count ) { count = VGA::VGA_SIZE - offset; }
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memcpy(dest, VGA::VGA + offset, count);
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offset += count;
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return count;
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}
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ssize_t DevVGA::Write(const uint8_t* src, size_t count)
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{
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if ( offset == VGA::VGA_SIZE && count ) { errno = ENOSPC; return -1; }
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if ( VGA::VGA_SIZE - offset < count ) { count = VGA::VGA_SIZE - offset; }
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memcpy(VGA::VGA + offset, src, count);
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offset = (offset + count) % VGA::VGA_SIZE;
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VGA::SetCursor(VGA::WIDTH, VGA::HEIGHT-1);
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#ifdef PLATFORM_SERIAL
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SerialTerminal::OnVGAModified();
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#endif
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return count;
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}
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bool DevVGA::IsReadable()
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{
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return true;
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}
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bool DevVGA::IsWritable()
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{
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return true;
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}
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size_t DevVGA::BlockSize()
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{
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return 1;
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}
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uintmax_t DevVGA::Size()
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{
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return VGA::VGA_SIZE;
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}
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uintmax_t DevVGA::Position()
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{
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return offset;
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}
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bool DevVGA::Seek(uintmax_t position)
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{
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if ( VGA::VGA_SIZE < position ) { errno = EINVAL; return false; }
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offset = position;
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return true;
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}
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bool DevVGA::Resize(uintmax_t size)
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{
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if ( size == VGA::VGA_SIZE ) { return false; }
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errno = ENOSPC;
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return false;
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}
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} // namespace Sortix
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