Add LAPIC timer

build.sh

@@ -2,9 +2,12 @@
 set -euo pipefail
 rm -rf img
 mkdir -p img/boot/efi/boot
-cd lib/acpica-build && make -j4 && cd ../..
+cd lib/acpica-build
-cd kernel && cargo build --release && cd ..
+cd ../../kernel
-cd loader && cargo build --release && cd ..
+cargo build --release
+cd ../loader
+cargo build --release
+cd ..
 cp target/x86_64-unknown-uefi/release/loader.efi img/boot/efi/boot/bootx64.efi
 cd img
 dd if=/dev/zero of=boot.img bs=1M count=16 status=none

kernel/src/main.rs

@@ -21,7 +21,7 @@ use kernel_common::{
     paging::{KERNEL_HEAP_INITIAL_SIZE, KERNEL_HEAP_START},
 };
 use log::{error, info};
-use sys::{acpica::AcpiInitializeTables, acpica_osl::AE_OK, hpet::setup_hpet, madt::parse_madt, pic::disable_pic};
+use sys::{acpica::AcpiInitializeTables, acpica_osl::AE_OK, hpet::setup_hpet, lapic::setup_lapic_timer, madt::parse_madt, pic::disable_pic};
 
 mod cpu;
 mod misc;
@@ -57,6 +57,7 @@ extern "C" fn main(temp_loader_struct: *const LoaderStruct) -> ! {
     }
     parse_madt();
     setup_hpet();
+    setup_lapic_timer();
     loop {
         hlt();
     }

kernel/src/sys/lapic.rs

@@ -1,16 +1,23 @@
 use core::{
     ptr::null_mut,
-    sync::atomic::{AtomicPtr, AtomicU8, Ordering},
+    sync::atomic::{AtomicPtr, AtomicU8, AtomicUsize, Ordering},
 };
 
 use crate::cpu::paging::map_physical;
 
+use super::hpet::early_sleep;
+
 const REGISTER_ID: usize = 8;
 const REGISTER_EOI: usize = 0x2c;
 const REGISTER_SPURIOUS_INT: usize = 0x3c;
+const REGISTER_TIMER_LVT: usize = 0xc8;
+const REGISTER_TIMER_INITIAL_COUNT: usize = 0xe0;
+const REGISTER_TIMER_CURRENT_COUNT: usize = 0xe4;
+const REGISTER_TIMER_DIVIDE: usize = 0xf8;
 
 static ADDRESS: AtomicPtr<u32> = AtomicPtr::new(null_mut());
 pub static BSP_LAPIC_ID: AtomicU8 = AtomicU8::new(0);
+static TICKS_PER_MS: AtomicUsize = AtomicUsize::new(0);
 
 pub fn send_eoi() {
     let address = ADDRESS.load(Ordering::Relaxed);
@@ -27,3 +34,25 @@ pub fn setup_lapic(phys: u64) {
     }
     send_eoi();
 }
+fn calibrate_timer() {
+    let address = ADDRESS.load(Ordering::Relaxed);
+    unsafe {
+        address.add(REGISTER_TIMER_INITIAL_COUNT).write_volatile(0xffffffff);
+    }
+    early_sleep(10);
+    let ticks_in_10ms = 0xffffffff - unsafe { address.add(REGISTER_TIMER_CURRENT_COUNT).read_volatile() };
+    TICKS_PER_MS.store(ticks_in_10ms as usize / 10, Ordering::Relaxed);
+    unsafe {
+        address.add(REGISTER_TIMER_INITIAL_COUNT).write_volatile(0);
+    }
+}
+pub fn setup_lapic_timer() {
+    let address = ADDRESS.load(Ordering::Relaxed);
+    unsafe {
+        address.add(REGISTER_TIMER_DIVIDE).write_volatile(3);
+    }
+    calibrate_timer();
+    unsafe {
+        address.add(REGISTER_TIMER_LVT).write_volatile(254);
+    }
+}

kernel/src/sys/madt.rs

@@ -10,17 +10,16 @@ use super::{
     lapic::setup_lapic,
 };
 
-fn process_subtables(subtable_address: u64, end_address: u64, target_type: u8, handler: &mut dyn FnMut(u64)) {
+fn process_subtables(subtable_address: u64, end_address: u64, subtable_type: u8, handler: &mut dyn FnMut(u64)) {
     let mut subtable_address_i = subtable_address;
     while subtable_address_i < end_address {
         let subtable_header = unsafe { &*(subtable_address_i as *const acpi_subtable_header) };
-        if subtable_header.Type == target_type {
+        if subtable_header.Type == subtable_type {
             handler(subtable_address_i);
         }
         subtable_address_i += subtable_header.Length as u64;
     }
 }
-
 pub fn parse_madt() {
     let madt: &acpi_table_madt;
     let signature = b"APIC" as *const u8;