From 38d1712e31e60de9f2afe85873b2174e002e3e99 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sat, 26 Mar 2022 21:06:07 +0100
Subject: kernel: IRQs; PS/2 keyboard support

---
 src/kernel/arch/i386/interrupts/irq.c | 41 +++++++++++++++++++++++++++++++++++
 src/kernel/arch/i386/interrupts/irq.h |  8 +++++++
 src/kernel/arch/i386/interrupts/isr.c |  8 +++++++
 3 files changed, 57 insertions(+)
 create mode 100644 src/kernel/arch/i386/interrupts/irq.c
 create mode 100644 src/kernel/arch/i386/interrupts/irq.h

(limited to 'src/kernel/arch/i386/interrupts')

diff --git a/src/kernel/arch/i386/interrupts/irq.c b/src/kernel/arch/i386/interrupts/irq.c
new file mode 100644
index 0000000..cb33bc8
--- /dev/null
+++ b/src/kernel/arch/i386/interrupts/irq.c
@@ -0,0 +1,41 @@
+#include <kernel/arch/i386/interrupts/irq.h>
+#include <kernel/arch/i386/port_io.h>
+#include <stdint.h>
+
+static const int PIC1 = 0x20;
+static const int PIC2 = 0xA0;
+
+static void irq_unmask(uint8_t line) {
+	uint16_t pic = line < 8 ? PIC1 : PIC2;
+	line &= 7;
+
+	port_out8(pic+1, port_in8(pic+1) & ~(1 << line));
+}
+
+void irq_init(void) {
+	port_out8(PIC1, 0x11);  /* start init sequence */
+	port_out8(PIC2, 0x11);
+
+	port_out8(PIC1+1, 0x20);   /* interrupt offsets */
+	port_out8(PIC2+1, 0x30);
+
+	port_out8(PIC1+1, 0x4);   /* just look at the osdev wiki lol */
+	port_out8(PIC2+1, 0x2);
+
+	port_out8(PIC1+1, 0x1);   /* 8086 mode */
+	port_out8(PIC2+1, 0x1);
+
+	port_out8(PIC1+1, 0xfd); /* mask */
+	port_out8(PIC2+1, 0xff);
+}
+
+void irq_eoi(uint8_t line) {
+	port_out8(PIC1, 0x20);
+	if (line >= 8)
+		port_out8(PIC2, 0x20);
+}
+
+void irq_interrupt_flag(bool flag) {
+	if (flag)	asm("sti" : : : "memory");
+	else		asm("cli" : : : "memory");
+}
diff --git a/src/kernel/arch/i386/interrupts/irq.h b/src/kernel/arch/i386/interrupts/irq.h
new file mode 100644
index 0000000..73d4af2
--- /dev/null
+++ b/src/kernel/arch/i386/interrupts/irq.h
@@ -0,0 +1,8 @@
+#pragma once
+#include <stdbool.h>
+#include <stdint.h>
+
+void irq_init(void);
+void irq_eoi(uint8_t line);
+
+void irq_interrupt_flag(bool flag);
diff --git a/src/kernel/arch/i386/interrupts/isr.c b/src/kernel/arch/i386/interrupts/isr.c
index 9d8bb6c..1448f44 100644
--- a/src/kernel/arch/i386/interrupts/isr.c
+++ b/src/kernel/arch/i386/interrupts/isr.c
@@ -1,4 +1,7 @@
+#include <kernel/arch/i386/interrupts/irq.h>
 #include <kernel/arch/i386/interrupts/isr.h>
+#include <kernel/arch/i386/port_io.h>
+#include <kernel/arch/i386/tty/keyboard.h>
 #include <kernel/arch/io.h>
 #include <kernel/panic.h>
 #include <kernel/proc.h>
@@ -16,6 +19,11 @@ void isr_stage3(int interrupt) {
 			isr_test_interrupt_called = true;
 			return;
 
+		case 0x21:; // keyboard irq
+			keyboard_recv(port_in8(0x60));
+			irq_eoi(1);
+			return;
+
 		default:
 			// TODO check if the exception was in the kernel
 			process_kill(process_current, interrupt);
-- 
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