From f6cdc3005df1942024e5c9ba5418d124788dfa76 Mon Sep 17 00:00:00 2001
From: Julien CLEMENT <julien.clement@epita.fr>
Date: Mon, 26 Jul 2021 14:15:21 +0200
Subject: [PATCH] feat(pit): add pit initialization and handler

Signed-off-by: Julien CLEMENT <julien.clement@epita.fr>
---
 k/events/idt.c     |  4 +---
 k/events/pic/pic.c |  1 +
 k/events/pic/pit.c | 14 ++++++++++++++
 k/events/pic/pit.h | 10 +++++++++-
 4 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/k/events/idt.c b/k/events/idt.c
index 69f2176..179018a 100644
--- a/k/events/idt.c
+++ b/k/events/idt.c
@@ -46,8 +46,6 @@ static struct idt_entry_descriptor idt_entries_descriptors[IDT_NB_ENTRIES] = {
 
 void interrupt_handler(struct isr_param *isr_param)
 {
-    printf("Oh no %d!\r\n", isr_param->int_vector);
-
     switch (isr_param->int_vector)
     {
         case PIT_INT_VECTOR:
@@ -58,7 +56,7 @@ void interrupt_handler(struct isr_param *isr_param)
             break;
     }
 
-    if (isr_param->int_vector > IDT_RESERVED_ENTRIES
+    if (isr_param->int_vector >= IDT_RESERVED_ENTRIES
             && isr_param->int_vector < IDT_RESERVED_ENTRIES + 16)
         acknowledge(isr_param->int_vector);
 }
diff --git a/k/events/pic/pic.c b/k/events/pic/pic.c
index 47ec9cb..1ade6de 100644
--- a/k/events/pic/pic.c
+++ b/k/events/pic/pic.c
@@ -44,6 +44,7 @@ void init_pic(void)
     send_icw4();
     mask_irqs();
     init_keyboard();
+    init_pit();
     asm volatile("sti");
 }
 
diff --git a/k/events/pic/pit.c b/k/events/pic/pit.c
index d0510d1..bc48849 100644
--- a/k/events/pic/pit.c
+++ b/k/events/pic/pit.c
@@ -1,9 +1,23 @@
 #include "pit.h"
+#include "io.h"
+#include "stdio.h"
+
+static unsigned long ticks = 0;
 
 void pit_handler(void)
 {
+    ++ticks;
 }
 
 unsigned long gettick(void)
 {
+    return ticks;
+}
+
+void init_pit(void)
+{
+    outb(PIT_CONTROL_REG, PIT_MODE_2 | PIT_RW_LSB | PIT_RW_MSB);
+
+    outb(PIT_COUNTER_0, PIT_DIVIDER & 0xff);
+    outb(PIT_COUNTER_0, PIT_DIVIDER >> 8);
 }
diff --git a/k/events/pic/pit.h b/k/events/pic/pit.h
index 348d885..200cec1 100644
--- a/k/events/pic/pit.h
+++ b/k/events/pic/pit.h
@@ -4,9 +4,17 @@
 #define PIT_COUNTER_0 0x40
 #define PIT_COUNTER_1 0x41
 #define PIT_COUNTER_2 0x42
-#define PIT_CONTROL_REGISTER 0x43
+#define PIT_CONTROL_REG 0x43
+
+#define PIT_MODE_2 (0x2 << 1)
+
+#define PIT_RW_LSB (0x1 << 4)
+#define PIT_RW_MSB (0x1 << 5)
+
+#define PIT_DIVIDER 11931
 
 void pit_handler(void);
 unsigned long gettick(void);
+void init_pit(void);
 
 #endif /* !PIT_H */