Add keyboard support

6 files changed, 178 insertions, 4 deletions

diff --git a/kernel/io/keyboard/keyboard_handler.c b/kernel/io/keyboard/keyboard_handler.c
new file mode 100644
index 0000000..86a50a7
--- /dev/null
+++ b/kernel/io/keyboard/keyboard_handler.c
@@ -0,0 +1,73 @@
+#include "../../interrupt_descriptor_table.h"
+#include "../vga/text_mode_display.h"
+#include "scancode_map.h"
+
+extern void keyboard_handler(void);
+extern char read_port(unsigned short port);
+extern void write_port(unsigned short port, unsigned char data);
+extern void load_idt(unsigned long *idt_ptr);
+
+struct idt_entry keyboard_idt[256];
+
+void init_keyboard_idt()
+{
+  unsigned long keyboard_address;
+  unsigned long idt_address;
+  unsigned long idt_ptr[2];
+
+  // Build IDT entry
+  keyboard_address = (unsigned long) keyboard_handler;
+
+  keyboard_idt[0x21].offset_lowerbits = keyboard_address & 0xffff;
+  keyboard_idt[0x21].selector = 0x08; // Offset by 0x08
+  keyboard_idt[0x21].zero = 0;
+  keyboard_idt[0x21].type_attr = 0x8E; // Interrupt gate addr
+  keyboard_idt[0x21].offset_higherbits = (keyboard_address & 0xffff0000) >> 16;
+
+  idt_address = (unsigned long) keyboard_idt;
+  idt_ptr[0] = (sizeof(struct idt_entry) * 256) + ((idt_address & 0xffff) << 16);
+  idt_ptr[1] = idt_address >> 16;
+
+  // Init PIC 1 @ 0x20
+  write_port(0x20, 0x11);
+  write_port(0x21, 0x20);
+  write_port(0x21, 0x00);
+  write_port(0x21, 0x01);
+  write_port(0x21, 0xff);
+
+  // PIC 2 @ 0xA0
+  write_port(0xA0, 0x11);
+  write_port(0xA1, 0x28);
+  write_port(0xA1, 0x00);
+  write_port(0xA1, 0x01);
+  write_port(0xA1, 0xff);
+
+  load_idt(idt_ptr);
+}
+
+void init_keyboard_handler()
+{
+  init_keyboard_idt();
+
+  write_port(0x21, 0xFD);
+}
+
+int isKeyup(int scancode)
+{
+  return scancode & 0x80;
+}
+
+void handle_keypress() {
+
+  // Ack the interrupt
+  write_port(0x20, 0x20);
+
+  unsigned char scancode = read_port(0x60);
+
+  if(!isKeyup(scancode))
+  {
+    char pressed_key = scancode_map[scancode];
+    vga_print_raw(pressed_key);
+  }
+
+}
diff --git a/kernel/io/keyboard/keyboard_handler.h b/kernel/io/keyboard/keyboard_handler.h
new file mode 100644
index 0000000..f56f4f2
--- /dev/null
+++ b/kernel/io/keyboard/keyboard_handler.h
@@ -0,0 +1 @@
+void init_keyboard_handler();
\ No newline at end of file
diff --git a/kernel/io/keyboard/scancode_map.h b/kernel/io/keyboard/scancode_map.h
new file mode 100644
index 0000000..e48a1f6
--- /dev/null
+++ b/kernel/io/keyboard/scancode_map.h
@@ -0,0 +1,93 @@
+char scancode_map[128] =
+{
+  0xFF, // Keyboard error code
+  0, // Esc
+  '1',
+  '2',
+  '3',
+  '4',
+  '5',
+  '6',
+  '7', 
+  '8',
+  '9',
+  '0', 
+  '-', 
+  '=', 
+  '\b', // Backspace
+  '\t', // Tab
+  'q',
+  'w', 
+  'e', 
+  'r', 
+  't', 
+  'y',
+  'u',
+  'i', 
+  'o',
+  'p',
+  '[',
+  ']', 
+  '\n', // Enter
+  0, // Ctrl
+  'a', 
+  's', 
+  'd', 
+  'f', 
+  'g', 
+  'h', 
+  'j', 
+  'k', 
+  'l', 
+  ';',
+  '\'', 
+  '`',
+  0, // Left Shift
+  '\\',
+  'z',
+  'x',
+  'c', 
+  'v', 
+  'b',
+  'n',
+  'm', 
+  ',',
+  '.',
+  '/', 
+  0, // Right shift 
+  '*',
+  0, // Alt
+  ' ', // Space
+  0, // Caps
+  0, // F1 ...
+  0,
+  0,
+  0, 
+  0, 
+  0, 
+  0, 
+  0, 
+  0,
+  0, // F10
+  0, // Numlock
+  0, // Scroll lock
+  0, // Home
+  0, // Up
+  0, // PgUp
+  '-',
+  0, // Left
+  0, // Numpad 5
+  0, // Right
+  '+',
+  0, // End
+  0, // Down
+  0, // PgDown
+  0, // Ins
+  0, // Del
+  0, // Alt-Sysrq
+  0, // n/a
+  0, // n/a
+  0, // F11
+  0, // F12
+  0, // Others are undefined
+};
\ No newline at end of file
diff --git a/kernel/io/vga/text_mode_diplay.h b/kernel/io/vga/text_mode_diplay.h
deleted file mode 100644
index 9441925..0000000
--- a/kernel/io/vga/text_mode_diplay.h
+++ /dev/null
@@ -1,4 +0,0 @@
-void vga_clear_screen();
-void vga_print(char *msg);
-void vga_print_ln(char *msg);
-void vga_set_text_colour(int foreground, int background);
\ No newline at end of file
diff --git a/kernel/io/vga/text_mode_display.c b/kernel/io/vga/text_mode_display.c
index 4844524..bfee909 100644
--- a/kernel/io/vga/text_mode_display.c
+++ b/kernel/io/vga/text_mode_display.c
@@ -39,4 +39,10 @@ void vga_print_ln(char *msg)
 void vga_set_text_colour(int foreground, int background) 
 {
   char_attribute_byte = (background << 4) | foreground;
+}
+
+void vga_print_raw(unsigned char byte)
+{
+  video_ram[cursor_pos++] = byte;
+  video_ram[cursor_pos++] = char_attribute_byte;
 }
\ No newline at end of file
diff --git a/kernel/io/vga/text_mode_display.h b/kernel/io/vga/text_mode_display.h
new file mode 100644
index 0000000..48bae85
--- /dev/null
+++ b/kernel/io/vga/text_mode_display.h
@@ -0,0 +1,5 @@
+void vga_clear_screen();
+void vga_print(char *msg);
+void vga_print_ln(char *msg);
+void vga_set_text_colour(int foreground, int background);
+void vga_print_raw(unsigned char byte);
\ No newline at end of file