From 7dcd88ccf634b8636c055314e426805750b53556 Mon Sep 17 00:00:00 2001
From: 82marbag <69267416+82marbag@users.noreply.github.com>
Date: Fri, 23 Oct 2020 07:00:38 -0400
Subject: [PATCH] drivers: PIT delivered with APIC

PIT interrupt routed to cpus using IOAPIC IRQ delivery

Signed-off-by: Daniele Ahmed <ahmeddan amazon c;om>
---
 common/setup.c        |  2 +-
 drivers/pit.c         | 11 ++++++++---
 include/drivers/pit.h |  2 +-
 3 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/common/setup.c b/common/setup.c
index f436f9e7..88dddc80 100644
--- a/common/setup.c
+++ b/common/setup.c
@@ -228,7 +228,7 @@ void __noreturn __text_init kernel_start(uint32_t multiboot_magic,
     uart_input_init(0);
 
     /* Initialize Programmable Interrupt Timer */
-    init_pit();
+    init_pit(0);
 
     /* Jump from .text.init section to .text */
     asm volatile("push %0; ret" ::"r"(&kernel_main));
diff --git a/drivers/pit.c b/drivers/pit.c
index bedef063..ef63cb6e 100644
--- a/drivers/pit.c
+++ b/drivers/pit.c
@@ -22,23 +22,28 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
+#include <apic.h>
 #include <atomic.h>
 #include <drivers/pic.h>
 #include <drivers/pit.h>
+#include <ioapic.h>
 #include <lib.h>
 #include <time.h>
 
 static volatile uint64_t ticks = 0;
 
-void init_pit(void) {
+void init_pit(uint8_t dst_cpus) {
     outb(PIT_COMMAND_PORT,
          PIT_CHANNEL_0 & PIT_ACCESS_MODE_LH & PIT_OP_MODE_RATE & PIT_BCD_MODE);
     outb(PIT_DATA_PORT_CH0, PIT_FREQUENCY & 0xFF);          /* send low byte */
     outb(PIT_DATA_PORT_CH0, (PIT_FREQUENCY & 0xFF00) >> 8); /* send high byte */
-    pic_enable_irq(PIC1_DEVICE_SEL, PIT_IRQ);
+    configure_isa_irq(PIT_IRQ, PIT_IRQ0_OFFSET, IOAPIC_DEST_MODE_PHYSICAL, dst_cpus);
 }
 
-void pit_interrupt_handler(void) { ++ticks; }
+void pit_interrupt_handler(void) {
+    ++ticks;
+    apic_EOI();
+}
 
 void pit_sleep(uint64_t ms) {
     uint64_t end = ticks + ms;
diff --git a/include/drivers/pit.h b/include/drivers/pit.h
index a66dd688..a3a8310c 100644
--- a/include/drivers/pit.h
+++ b/include/drivers/pit.h
@@ -56,7 +56,7 @@ typedef enum pit_operational_mode pit_operational_mode_t;
 
 #define PIT_BCD_MODE (~(1 << 0))
 
-extern void init_pit(void);
+extern void init_pit(uint8_t dst_cpus);
 extern void pit_interrupt_handler(void);
 extern void pit_sleep(uint64_t ms);