From cb8a12eed029e4aefa62a6c035f6927c84362218 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juhani=20Krekel=C3=A4?= <juhani@krekelä.fi>
Date: Wed, 19 Jan 2022 21:22:12 +0200
Subject: [PATCH] Set up ps/2 controller

---
 kernel.c | 132 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 130 insertions(+), 2 deletions(-)

diff --git a/kernel.c b/kernel.c
index b8afa6f..ab9219a 100644
--- a/kernel.c
+++ b/kernel.c
@@ -87,6 +87,12 @@ void terminal_putentryat(char c, uint8_t color, size_t x, size_t y)
 
 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;
@@ -106,11 +112,133 @@ void terminal_writestring(const char* data)
 	terminal_write(data, strlen(data));
 }
 
+// (out|in)port from sortix, Copyright (c) 2014, 2015 Jonas 'Sortie' Termansen.
+void outport8(uint16_t port, uint8_t value)
+{
+	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));
+	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 single_channel = false;
+
+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 init_8042(void) {
+	// Disable devices
+	command_8042(0xad);
+	command_8042(0xa7);
+
+	// Flush output buffer
+	while (status_8042() & (1<<0))
+		(void) read_8042();
+	
+	// Read configuration
+	uint8_t config = read_config_8042();
+	translation_initially = config & (1<<6);
+	single_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 (!single_channel) {
+		command_8042(0xae);
+		single_channel = read_config_8042() & (1<<5);
+		if (!single_channel)
+			command_8042(0xa7);
+	}
+	if (single_channel)
+		terminal_writestring("Single-channel ps/2 controller\n");
+	else
+		terminal_writestring("Dual-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 (!single_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 (!single_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);
+}
+
 void kernel_main(void)
 {
 	/* Initialize terminal interface */
 	terminal_initialize();
 
-	/* Newline support is left as an exercise. */
-	terminal_writestring("Hello, kernel World!\n");
+	init_8042();
+	if (single_channel)
+
+	terminal_writestring("\nHanging\n");
 }