From 9b52ae58e84c213f879c9fd1c7702f9bd51c498f Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Wed, 7 Dec 2022 23:13:51 -0500
Subject: [PATCH] Get local APIC timer ready to run

---
 src/hulk/apic.d | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/src/hulk/apic.d b/src/hulk/apic.d
index 1fb61df..3050f77 100644
--- a/src/hulk/apic.d
+++ b/src/hulk/apic.d
@@ -9,6 +9,8 @@ import hulk.acpi;
 
 struct apic
 {
+    private enum uint PERIODIC_MODE = 0x2_0000u;
+
     static struct ApicRegister
     {
         public uint value;
@@ -49,10 +51,11 @@ struct apic
         ApicRegister divide_configuration;
     }
 
+    private static __gshared ApicRegisters * apic_registers;
+
     public static void initialize()
     {
-        ApicRegisters * apic_registers =
-            cast(ApicRegisters *)acpi.apic_address;
+        apic_registers = cast(ApicRegisters *)acpi.apic_address;
         hurl.map(cast(ulong)apic_registers, cast(ulong)apic_registers,
                 PT_WRITABLE | PT_WRITE_THROUGH | PT_DISABLE_CACHE | PT_NO_EXECUTE);
         klog.writefln("LAPIC ID: 0x%08x", apic_registers.lapic_id.value);
@@ -60,8 +63,19 @@ struct apic
         /* Enable local APIC to receive interrupts and set spurious interrupt
          * vector to 0xFF. */
         apic_registers.spurious_interrupt_vector.value = 0x1FFu;
-        apic_registers.lvt_timer.value = 0x70u;
+        apic_registers.lvt_timer.value = 0x70u | PERIODIC_MODE;
         apic_registers.lvt_lint[0].value = 0x71u;
         apic_registers.lvt_lint[1].value = 0x72u;
+        apic_registers.divide_configuration.value = 3u;
+    }
+
+    private static void eoi()
+    {
+        apic_registers.eoi.value = 0u;
+    }
+
+    public static void isr()
+    {
+        eoi();
     }
 }