From a19ae009f9f571d25a90aca5cc5e05d3c76e1aed Mon Sep 17 00:00:00 2001
From: Danny Holman <dholman@gymli.org>
Date: Fri, 16 Feb 2024 13:29:51 -0600
Subject: arch: i386: add basic keyboard driver

Add a basic driver for the PS/2 keyboard. This driver just prints
whatever it receives back out to the framebuffer.

Signed-off-by: Danny Holman <dholman@gymli.org>
---
 arch/i386/kernel/keyboard.c | 142 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 arch/i386/kernel/keyboard.c

(limited to 'arch/i386/kernel/keyboard.c')

diff --git a/arch/i386/kernel/keyboard.c b/arch/i386/kernel/keyboard.c
new file mode 100644
index 0000000..4e4bc9b
--- /dev/null
+++ b/arch/i386/kernel/keyboard.c
@@ -0,0 +1,142 @@
+#include <kernel/keyboard.h>
+#include <kernel/framebuffer.h>
+#include <kernel/pic.h>
+
+#define C(k)            (k - '@')
+
+static uint8_t keymap_modifiers[256] = {
+        [0x1D] KB_CTL,
+        [0x2A] KB_SHIFT,
+        [0x36] KB_SHIFT,
+        [0x38] KB_ALT,
+        [0x9D] KB_CTL,
+        [0xB8] KB_ALT
+};
+
+static uint8_t keymap_toggles[256] = {
+        [0x3A] KB_CPSLK,
+        [0x45] KB_NUMLK,
+        [0x46] KB_SCLLK
+};
+
+static uint8_t keymap_normal[256] = {
+        0, 0x1B, '1', '2', '3', '4', '5', '6',
+        '7', '8', '9', '0', '-', '=', '\b', '\t',
+        'q', 'w', 'e', 'r', 't', 'y', 'u', 'i',
+        'o', 'p', '[', ']', '\n', 0, 'a', 's',
+        'd', 'f', 'g', 'h', 'j', 'k', 'l', ';',
+        '\'', '`', 0, '\\', 'z', 'x', 'c', 'v',
+        'b', 'n', 'm', ',', '.', '/', 0, '*',
+        0, ' ', 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, '7',
+        '8', '9', '-', '4', '5', '6', '+', '1',
+        '2', '3', '0', '.', 0, 0, 0, 0,
+        [0x9C] '\n',
+        [0xB5] '/',
+        [0xC8] KB_UP,
+        [0xD0] KB_DOWN,
+        [0xC9] KB_PGUP,
+        [0xD1] KB_PGDN,
+        [0xCB] KB_LEFT,
+        [0xCD] KB_RGHT,
+        [0x97] KB_HOME,
+        [0xCF] KB_END,
+        [0xD2] KB_INS,
+        [0xD3] KB_DEL
+};
+
+static uint8_t keymap_shifted[256] = {
+        0, 0x33, '!', '@', '#', '$', '%', '^',
+        '&', '*', '(', ')', '_', '+', '\b', '\t',
+        'Q', 'W', 'E', 'R', 'T', 'Y', 'U', 'I',
+        'O', 'P', '{', '}', '\n', 0, 'A', 'S',
+        'D', 'F', 'G', 'H', 'J', 'K', 'L', ':',
+        '"', '~', 0, '|', 'Z', 'X', 'C', 'V',
+        'B', 'N', 'M', '<', '>', '?', 0, '*',
+        0, ' ', 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, '7',
+        '8', '9', '-', '4', '5', '6', '+', '1',
+        '2', '3', '0', '.', 0, 0, 0, 0,
+        [0x9C] '\n',
+        [0xB5] '/',
+        [0xC8] KB_UP,
+        [0xD0] KB_DOWN,
+        [0xC9] KB_PGUP,
+        [0xD1] KB_PGDN,
+        [0xCB] KB_LEFT,
+        [0xCD] KB_RGHT,
+        [0x97] KB_HOME,
+        [0xCF] KB_END,
+        [0xD2] KB_INS,
+        [0xD3] KB_DEL
+};
+
+static uint8_t keymap_control[256] = {
+        0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0,
+        C('Q'), C('W'), C('E'), C('R'), C('T'), C('Y'), C('U'), C('I'),
+        C('O'), C('P'), 0, 0, '\r', 0, C('A'), C('S'),
+        C('D'), C('F'), C('G'), C('H'), C('J'), C('K'), C('L'), 0,
+        0, 0, 0, C('\\'), C('Z'), C('X'), C('C'), C('V'),
+        C('B'), C('N'), C('M'), 0, 0, C('/'), 0, 0,
+        [0x9C] '\r',
+        [0xB5] C('/'),
+        [0xC8] KB_UP,
+        [0xD0] KB_DOWN,
+        [0xC9] KB_PGUP,
+        [0xD1] KB_PGDN,
+        [0xCB] KB_LEFT,
+        [0xCD] KB_RGHT,
+        [0x97] KB_HOME,
+        [0xCF] KB_END,
+        [0xD2] KB_INS,
+        [0xD3] KB_DEL
+};
+
+static uint8_t* keymaps[4] = {
+        keymap_normal,
+        keymap_shifted,
+        keymap_control,
+        keymap_control,
+};
+
+char keyboard_getchar(void) {
+        static int shift = 0;
+        uint8_t st = inb(KB_STAT);
+        if ((st & KB_DIB) == 0)
+                return -1;
+
+        uint8_t data = inb(KB_DATA);
+
+        if (data == 0xE0) {
+                shift |= KB_E0ESC;
+                return -1;
+        } else if (data & 0x80) {
+                if (!(shift & KB_E0ESC))
+                        data &= 0x7F;
+                shift &= ~(keymap_modifiers[data] | KB_E0ESC);
+                return -1;
+        } else if (shift & KB_E0ESC) {
+                data |= 0x80;
+                shift &= ~KB_E0ESC;
+        }
+
+        shift |= keymap_modifiers[data];
+        shift ^= keymap_toggles[data];
+        char c = keymaps[shift & (KB_CTL | KB_SHIFT)][data];
+        if (shift & KB_CPSLK) {
+                if ('a' <= c && c <= 'z')
+                        c += 'A' - 'a';
+                else if ('A' <= c && c <= 'Z')
+                        c += 'a' - 'A';
+        }
+        return c;
+}
+
+void keyboard_handler(struct isr_frame *frame) {
+        char c = keyboard_getchar();
+        // TODO: actually put this in a buffer
+        if (c != -1)
+                fb_putchar(c);
+        return;
+}
-- 
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