From 068368d0bedc34f561ab0c9dd614c02b346d1d4e Mon Sep 17 00:00:00 2001
From: Vegard Storheil Eriksen <zyp@jvnv.net>
Date: Wed, 20 Jan 2010 22:18:02 +0100
Subject: Added IRQ-support and timer interrupt.

---
 kernel/SConscript |  2 +-
 kernel/idt.c      | 19 +++++++++++++++++++
 kernel/irq.c      | 42 ++++++++++++++++++++++++++++++++++++++++++
 kernel/irq.h      |  9 +++++++++
 kernel/main.c     |  6 ++++++
 5 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100644 kernel/irq.c
 create mode 100644 kernel/irq.h

diff --git a/kernel/SConscript b/kernel/SConscript
index 8b0ad5c..76d3aa6 100644
--- a/kernel/SConscript
+++ b/kernel/SConscript
@@ -27,4 +27,4 @@ kernel_bld = Builder(
 
 env.Append(BUILDERS = {'Kernel' : kernel_bld})
 
-kernel = env.Kernel('kernel', ['kernel.ld', 'entry.c', 'main.c', 'printf.c', 'gdt.c', 'idt.c', 'panic.c'])
+kernel = env.Kernel('kernel', ['kernel.ld', 'entry.c', 'main.c', 'printf.c', 'gdt.c', 'idt.c', 'irq.c', 'panic.c'])
diff --git a/kernel/idt.c b/kernel/idt.c
index 5633c61..66e1fb8 100644
--- a/kernel/idt.c
+++ b/kernel/idt.c
@@ -73,6 +73,22 @@ isr_panic(29);
 isr_panic(30);
 isr_panic(31);
 
+#include "irq.h"
+
+void tick() {
+	*(uint16_t*)(0xb8890) += 1;
+	irq_reset();
+}
+
+
+asm(
+	".globl isr_32\n"
+	"isr_32:\n"
+	"pusha\n"
+	"call tick\n"
+	"popa\n"
+	"iret\n"
+);
 
 void idt_init() {
 	idt_set_gate(0, (uint32_t)isr_0, 0x08, 0x8e00);
@@ -108,6 +124,9 @@ void idt_init() {
 	idt_set_gate(30, (uint32_t)isr_30, 0x08, 0x8e00);
 	idt_set_gate(31, (uint32_t)isr_31, 0x08, 0x8e00);
 	
+	void isr_32();
+	idt_set_gate(32, (uint32_t)isr_32, 0x08, 0x8e00);
+	
 	asm volatile(
 		"lidt (%0)\n"
 		: : "r" (&idtr)
diff --git a/kernel/irq.c b/kernel/irq.c
new file mode 100644
index 0000000..6034735
--- /dev/null
+++ b/kernel/irq.c
@@ -0,0 +1,42 @@
+#include "irq.h"
+#include "portio.h"
+
+void irq_init() {
+	// ICW1
+	outb(0x20, 0x11);
+	outb(0xa0, 0x11);
+	
+	// ICW2 - Offset.
+	outb(0x21, 0x20);
+	outb(0xa1, 0x28);
+	
+	// ICW3
+	outb(0x21, 0x04);
+	outb(0xa1, 0x02);
+	
+	// ICW4
+	outb(0x21, 0x01);
+	outb(0xa1, 0x01);
+	
+	// OCW1 - Mask.
+	outb(0x21, 0xfe);
+	outb(0xa1, 0xff);
+	
+	// Initialize timer.
+	// TODO: Move this elsewhere.
+	outb(0x43, 0x36);
+	outb(0x40, 0x00);
+	outb(0x40, 0x00);
+}
+
+void irq_reset() {
+	// OCW2
+	outb(0x20, 0x20);
+}
+
+void irq_reset_slave() {
+	// OCW2
+	outb(0xa0, 0x20);
+	
+	irq_reset();
+}
diff --git a/kernel/irq.h b/kernel/irq.h
new file mode 100644
index 0000000..2a5682a
--- /dev/null
+++ b/kernel/irq.h
@@ -0,0 +1,9 @@
+#ifndef IRQ_H
+#define IRQ_H
+
+void irq_init();
+
+void irq_reset();
+void irq_reset_slave();
+
+#endif
diff --git a/kernel/main.c b/kernel/main.c
index 55476ce..74ba441 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -1,6 +1,7 @@
 #include "printf.h"
 #include "gdt.h"
 #include "idt.h"
+#include "irq.h"
 
 void main() {
 	printf("main()\n");
@@ -11,6 +12,11 @@ void main() {
 	idt_init();
 	printf("IDT set.\n");
 	
+	irq_init();
+	printf("IRQs set.\n");
+	
+	asm volatile("sti");
+	
 	printf("Halting.\n");
 	
 	asm volatile(
-- 
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