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ps2-kbtest/kernel.c

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//#define PORT_DEBUG
/* Based on Bare Bones tutorial on OSDev wiki */
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
/* Check if the compiler thinks you are targeting the wrong operating system. */
#if defined(__linux__)
#error "You are not using a cross-compiler, you will most certainly run into trouble"
#endif
/* This tutorial will only work for the 32-bit ix86 targets. */
#if !defined(__i386__)
#error "This tutorial needs to be compiled with a ix86-elf compiler"
#endif
/* Hardware text mode color constants. */
enum vga_color {
VGA_COLOR_BLACK = 0,
VGA_COLOR_BLUE = 1,
VGA_COLOR_GREEN = 2,
VGA_COLOR_CYAN = 3,
VGA_COLOR_RED = 4,
VGA_COLOR_MAGENTA = 5,
VGA_COLOR_BROWN = 6,
VGA_COLOR_LIGHT_GREY = 7,
VGA_COLOR_DARK_GREY = 8,
VGA_COLOR_LIGHT_BLUE = 9,
VGA_COLOR_LIGHT_GREEN = 10,
VGA_COLOR_LIGHT_CYAN = 11,
VGA_COLOR_LIGHT_RED = 12,
VGA_COLOR_LIGHT_MAGENTA = 13,
VGA_COLOR_LIGHT_BROWN = 14,
VGA_COLOR_WHITE = 15,
};
static inline uint8_t vga_entry_color(enum vga_color fg, enum vga_color bg)
{
return fg | bg << 4;
}
static inline uint16_t vga_entry(unsigned char uc, uint8_t color)
{
return (uint16_t) uc | (uint16_t) color << 8;
}
size_t strlen(const char* str)
{
size_t len = 0;
while (str[len])
len++;
return len;
}
static const size_t VGA_WIDTH = 80;
static const size_t VGA_HEIGHT = 25;
size_t terminal_row;
size_t terminal_column;
uint8_t terminal_color;
uint16_t* terminal_buffer;
void terminal_initialize(void)
{
terminal_row = 0;
terminal_column = 0;
terminal_color = vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
terminal_buffer = (uint16_t*) 0xB8000;
for (size_t y = 0; y < VGA_HEIGHT; y++) {
for (size_t x = 0; x < VGA_WIDTH; x++) {
const size_t index = y * VGA_WIDTH + x;
terminal_buffer[index] = vga_entry(' ', terminal_color);
}
}
}
void terminal_setcolor(uint8_t color)
{
terminal_color = color;
}
void terminal_putentryat(char c, uint8_t color, size_t x, size_t y)
{
const size_t index = y * VGA_WIDTH + x;
terminal_buffer[index] = vga_entry(c, color);
}
void terminal_putchar(char c)
{
if (c == '\n') {
terminal_row++;
terminal_column = 0;
return;
}
terminal_putentryat(c, terminal_color, terminal_column, terminal_row);
if (++terminal_column == VGA_WIDTH) {
terminal_column = 0;
if (++terminal_row == VGA_HEIGHT)
terminal_row = 0;
}
}
void terminal_write(const char* data, size_t size)
{
for (size_t i = 0; i < size; i++)
terminal_putchar(data[i]);
}
void terminal_writestring(const char* data)
{
terminal_write(data, strlen(data));
}
const char hex[] = "0123456789abcdef";
void terminal_writehex(uint8_t byte) {
terminal_putchar(hex[byte >> 4]);
terminal_putchar(hex[byte & 0xf]);
}
// (out|in)port from sortix, Copyright (c) 2014, 2015 Jonas 'Sortie' Termansen.
void outport8(uint16_t port, uint8_t value)
{
#ifdef PORT_DEBUG
terminal_writestring("<out ");
terminal_writehex(port >> 8);
terminal_writehex(port);
terminal_writestring(" ");
terminal_writehex(value);
terminal_writestring(">");
#endif
asm volatile ("outb %1, %0" : : "dN" (port), "a" (value));
}
uint8_t inport8(uint16_t port)
{
uint8_t result;
asm volatile("inb %1, %0" : "=a" (result) : "dN" (port));
#ifdef PORT_DEBUG
terminal_writestring("<in ");
terminal_writehex(port >> 8);
terminal_writehex(port);
terminal_writestring(" ");
terminal_writehex(result);
terminal_writestring(">");
#endif
return result;
}
void command_8042(uint8_t command) {
outport8(0x64, command);
}
uint8_t status_8042(void) {
return inport8(0x64);
}
uint8_t read_8042(void) {
return inport8(0x60);
}
void write_8042(uint8_t data) {
outport8(0x60, data);
}
bool translation_initially;
bool dual_channel;
uint8_t read_config_8042(void) {
command_8042(0x20);
return read_8042();
}
void write_config_8042(uint8_t config) {
command_8042(0x60);
write_8042(config);
}
void flush_buffer() {
while (status_8042() & (1<<0))
(void) read_8042();
}
void init_8042(void) {
// Disable devices
command_8042(0xad);
command_8042(0xa7);
// Flush output buffer
flush_buffer();
// Read configuration
uint8_t config = read_config_8042();
translation_initially = config & (1<<6);
dual_channel = config & (1<<5);
// Disable IRQ
config &= ~(1<<0);
config &= ~(1<<1);
command_8042(0x60);
write_8042(config);
// Self test
terminal_writestring("8042 self-test... ");
command_8042(0xaa);
while (!(status_8042() & (1<<0)));
if (read_8042() != 0x55)
terminal_writestring("failed\n");
else
terminal_writestring("ok\n");
// Some controllers need this
command_8042(0x60);
write_8042(config);
// Determine number of channels
if (dual_channel) {
command_8042(0xa8);
dual_channel = !(read_config_8042() & (1<<5));
if (dual_channel)
command_8042(0xa7);
}
if (dual_channel)
terminal_writestring("Dual-channel ps/2 controller\n");
else
terminal_writestring("Single-channel ps/2 controller\n");
// Test channels
terminal_writestring("Testing channel 1... ");
command_8042(0xab);
if (read_8042() != 0)
terminal_writestring("failed\n");
else
terminal_writestring("ok\n");
if (dual_channel) {
terminal_writestring("Testing channel 2... ");
command_8042(0xa9);
if (read_8042() != 0)
terminal_writestring("failed\n");
else
terminal_writestring("ok\n");
}
// Enable devices
command_8042(0xae);
if (dual_channel)
command_8042(0xa8);
}
void enable_translation(void) {
uint8_t config = read_config_8042();
config |= 1<<6;
write_config_8042(config);
}
void disable_translation(void) {
uint8_t config = read_config_8042();
config &= ~(1<<6);
write_config_8042(config);
}
uint8_t read_keyboard(void) {
while (!(status_8042() & (1<<0)));
return read_8042();
}
void enable_scanning(void) {
flush_buffer();
write_8042(0xf4);
if (read_keyboard() != 0xfa)
terminal_writestring("Enabling scanning failed\n");
}
void disable_scanning(void) {
flush_buffer();
write_8042(0xf5);
if (read_keyboard() != 0xfa)
terminal_writestring("Disabling scanning failed\n");
}
void set_scancode_set(uint8_t set) {
flush_buffer();
write_8042(0xf0);
write_8042(set);
if (read_keyboard() != 0xfa)
terminal_writestring("Setting scancode set failed\n");
flush_buffer();
}
uint8_t get_scancode_set(void) {
flush_buffer();
write_8042(0xf0);
write_8042(0);
if (read_keyboard() != 0xfa)
terminal_writestring("Getting scancode set failed\n");
uint8_t set;
while ((set = read_keyboard()) == 0xfa);
return set;
}
#define KEY_A_SET1 0x1e
#define KEY_A_SET2 0x1c
#define KEY_A_MISINTERPRET 0x03
void print_key(uint8_t code) {
switch (code) {
case KEY_A_SET1: terminal_writestring("Set 1 A"); break;
case KEY_A_SET2: terminal_writestring("Set 2 A"); break;
case KEY_A_MISINTERPRET: terminal_writestring("Set 1 A misinterpreted as set 2 2"); break;
default:
terminal_writestring("Unknown byte ");
terminal_writehex(code);
break;
}
}
void key_prompt(uint8_t expect) {
enable_scanning();
terminal_writestring("Press A... ");
flush_buffer();
uint8_t code = read_keyboard();
if ( code == expect )
terminal_setcolor(vga_entry_color(VGA_COLOR_GREEN, VGA_COLOR_BLACK));
else
terminal_setcolor(vga_entry_color(VGA_COLOR_RED, VGA_COLOR_BLACK));
print_key(code);
if ( code == expect )
terminal_writestring("\n");
else
terminal_writestring("(!)\n");
terminal_setcolor(vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK));
read_keyboard(); // Key up
disable_scanning();
}
void kernel_main(void)
{
/* Initialize terminal interface */
terminal_initialize();
init_8042();
terminal_writestring("Assuming keyboard is channel 1\n");
terminal_setcolor(vga_entry_color(VGA_COLOR_BROWN, VGA_COLOR_BLACK));
terminal_writestring("\nNOTE: ");
terminal_setcolor(vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK));
terminal_writestring("If getting scancode set seems to hang, tap the 'A' key.\n");
terminal_writestring("\nTranslation initially ");
if (translation_initially)
terminal_writestring("on, scancode set initially set to... ");
else
terminal_writestring("off, scancode set initially set to... ");
terminal_writehex(get_scancode_set());
terminal_writestring("\n");
key_prompt(translation_initially ? KEY_A_SET1 : KEY_A_SET2);
disable_translation();
terminal_writestring("\nTranslation off, scancode set initially set to... ");
uint8_t initial_scancode = get_scancode_set();
terminal_writehex(initial_scancode);
terminal_writestring("\n");
key_prompt(initial_scancode == 1 ? KEY_A_SET1 : KEY_A_SET2);
terminal_writestring("Translation off, trying set 1... ");
set_scancode_set(1);
terminal_writestring("scancode set set to... ");
terminal_writehex(get_scancode_set());
terminal_writestring("\n");
key_prompt(KEY_A_SET1);
terminal_writestring("Translation off, trying set 2... ");
set_scancode_set(2);
terminal_writestring("scancode set set to... ");
terminal_writehex(get_scancode_set());
terminal_writestring("\n");
key_prompt(KEY_A_SET2);
enable_translation();
terminal_writestring("\nTranslation on, trying set 1... ");
set_scancode_set(1);
terminal_writestring("scancode set set to... ");
terminal_writehex(get_scancode_set());
terminal_writestring("\n");
key_prompt(KEY_A_MISINTERPRET);
terminal_writestring("Translation on, trying set 2... ");
set_scancode_set(2);
terminal_writestring("scancode set set to... ");
terminal_writehex(get_scancode_set());
terminal_writestring("\n");
key_prompt(KEY_A_SET1);
terminal_writestring("\nHanging\n");
}
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