Add support for reading keyboard

kernel/include/kernel/hw/keyboard.h

@@ -0,0 +1,67 @@
+#ifndef KEYBOARD_H
+#define KEYBOARD_H
+
+#include <stdint.h>
+
+constexpr unsigned short kb_ps2_data_port = 0x60;
+constexpr unsigned short kb_ps2_status_port = 0x64;
+constexpr unsigned short kb_ps2_cmd_port = 0x64;
+
+constexpr unsigned char kb_ps2_cmd_get_ccb = 0x20;
+constexpr unsigned char kb_ps2_cmd_set_ccb = 0x60;
+constexpr unsigned char kb_ps2_disable_port_2 = 0xA7;
+constexpr unsigned char kb_ps2_enable_port_2 = 0xA8;
+constexpr unsigned char kb_ps2_test_port_2 = 0xA9;
+constexpr unsigned char kb_ps2_test_controller = 0xAA;
+constexpr unsigned char kb_ps2_test_port_1 = 0xAB;
+constexpr unsigned char kb_ps2_disable_port_1 = 0xAD;
+constexpr unsigned char kb_ps2_enable_port_1 = 0xAE;
+constexpr unsigned char kb_ps2_read_controller_ip = 0xC0;
+constexpr unsigned char kb_ps2_read_controller_op = 0xD0;
+constexpr unsigned char kb_ps2_write_controller_op = 0xD0;
+constexpr unsigned char kb_ps2_reset = 0xFF;
+
+typedef union {
+	uint8_t raw;
+	struct {
+		uint8_t irq1_enable : 1;
+		uint8_t irq12_enable : 1;
+		uint8_t system_flag : 1;
+		uint8_t reserved1 : 1;
+		uint8_t port_1_clock_disable : 1;
+		uint8_t port_2_clock_disable : 1;
+		uint8_t port_1_tl_enable : 1;
+		uint8_t reserved2 : 1;
+	} __attribute__ ((packed));
+} kb_ps2_cfg_byte_t;
+
+typedef union {
+	uint8_t raw;
+	struct {
+		uint8_t system_reset : 1;
+		uint8_t a20_gate : 1;
+		uint8_t port_2_clock : 1;
+		uint8_t port_2_data : 1;
+		uint8_t op_buffer_is_port_1 : 1;
+		uint8_t op_buffer_is_port_2 : 1;
+		uint8_t port_1_clock : 1;
+		uint8_t port_1_data : 1;
+	} __attribute__ ((packed));
+} kb_ps2_controller_output_port_t;
+
+typedef union {
+	uint8_t raw;
+	struct {
+		uint8_t out_buffer_full : 1;
+		uint8_t in_buffer_full : 1;
+		uint8_t system_flag : 1;
+		uint8_t is_controller_command : 1;
+		uint8_t reserved : 2;
+		uint8_t is_timeout_error : 1;
+		uint8_t is_parity_error : 1;
+	} __attribute__ ((packed));
+} kb_ps2_status_register_t;
+
+void init_kb (void);
+
+#endif

kernel/src/kernel/entry.c

@@ -9,6 +9,7 @@
 #include <kernel/graphics.h>
 #include <kernel/handlers.h>
 #include <kernel/hardfonts/classic.h>
+#include <kernel/hw/keyboard.h>
 #include <kernel/hw/pic.h>
 #include <kernel/hw/timer.h>
 #include <kernel/idt.h>
@@ -104,6 +105,7 @@ static void print_info (void) {
 __attribute__ ((noreturn)) void _start_stage2 (void) {
 	init_graphics (framebuffer);
 	init_console (framebuffer->width, framebuffer->height, 40, 40, 1, 1, 2);
+	init_kb ();
 
 	for (int i = 0; i < 3; i++) // open stdin, stdout and stderr
 		do_syscall (SYSCALL_SYS_OPEN, (uint64_t)"/dev/tty1", 0, 0);

kernel/src/kernel/hw/keyboard.c

@@ -0,0 +1,89 @@
+#include <kernel/hw/keyboard.h>
+#include <kernel/hw/pic.h>
+#include <kernel/idt.h>
+#include <kernel/io.h>
+#include <utils/charqueue.h>
+
+static bool		  is_kb_setup = false;
+static charqueue* kb_keypress_charqueue;
+
+static inline kb_ps2_status_register_t kb_read_status_register (void) {
+	return (kb_ps2_status_register_t){.raw = inb (kb_ps2_status_port)};
+}
+
+static inline unsigned char kb_send_command (unsigned char command, bool will_return) {
+	while (kb_read_status_register ().in_buffer_full)
+		;
+	outb (kb_ps2_cmd_port, command);
+	if (!will_return) return 0;
+	while (!(kb_read_status_register ().out_buffer_full))
+		;
+	return inb (kb_ps2_data_port);
+}
+
+static inline void kb_send_data (unsigned char data) {
+	while (kb_read_status_register ().in_buffer_full)
+		;
+	outb (kb_ps2_data_port, data);
+}
+
+static inline unsigned char kb_read_data (void) {
+	while (!(kb_read_status_register ().out_buffer_full))
+		;
+	return inb (kb_ps2_data_port);
+}
+
+static inline kb_ps2_cfg_byte_t kb_read_cfg_byte (void) {
+	return (kb_ps2_cfg_byte_t){.raw = kb_send_command (kb_ps2_cmd_get_ccb, true)};
+}
+
+static inline void kb_write_cfg_byte (kb_ps2_cfg_byte_t cfg_byte) {
+	kb_send_command (kb_ps2_cmd_set_ccb, false);
+	kb_send_data (cfg_byte.raw);
+}
+
+static inline bool kb_reset (void) {
+	kb_send_data (kb_ps2_reset);
+	if (kb_read_data () != 0xFA) return false;
+	if (kb_read_data () != 0XAA) return false;
+	return true;
+}
+
+static registers_t* kb_handler (registers_t* registers) {
+	unsigned char scancode = kb_read_data ();
+	pic_send_eoi (1);
+	push_charqueue (kb_keypress_charqueue, scancode);
+	return registers;
+}
+
+void init_kb (void) {
+	kb_keypress_charqueue = create_charqueue ();
+
+	// TODO: actually verify the PS2 controller exists
+
+	kb_send_command (kb_ps2_disable_port_1, false);
+	kb_send_command (kb_ps2_disable_port_2, false);
+
+	while (kb_read_status_register ().out_buffer_full)
+		inb (kb_ps2_data_port);
+
+	kb_ps2_cfg_byte_t cfg_byte = kb_read_cfg_byte ();
+	cfg_byte.irq1_enable = cfg_byte.irq12_enable = 0;
+	cfg_byte.port_1_tl_enable = 0;
+	cfg_byte.port_1_clock_disable = 0;
+	kb_write_cfg_byte (cfg_byte);
+
+	if (kb_send_command (kb_ps2_test_controller, true) != 0x55) return;
+
+	kb_write_cfg_byte (cfg_byte);
+	kb_send_command (kb_ps2_enable_port_1, false);
+
+	cfg_byte.irq1_enable = 1;
+	kb_write_cfg_byte (cfg_byte);
+	is_kb_setup = kb_reset ();
+
+	if (kb_keypress_charqueue != nullptr) {
+		idt_register_handler (0x21, kb_handler);
+		pic_clr_mask (1);
+	}
+}