From f58d15a197f839ec45f02bbd41bf8b55298ec621 Mon Sep 17 00:00:00 2001
From: Mathieu Strypsteen <mathieu@strypsteen.me>
Date: Wed, 30 Oct 2024 18:15:18 +0100
Subject: [PATCH] Add early_sleep

---
 kernel/src/sys/hpet.rs                | 37 ++++++++++++++++++++++++---
 kernel/src/sys/madt.rs                |  6 +++--
 lib/acpica                            |  2 +-
 lib/kernel-common/src/instructions.rs | 10 ++++++++
 4 files changed, 49 insertions(+), 6 deletions(-)

diff --git a/kernel/src/sys/hpet.rs b/kernel/src/sys/hpet.rs
index d597a68..2858d76 100644
--- a/kernel/src/sys/hpet.rs
+++ b/kernel/src/sys/hpet.rs
@@ -1,8 +1,11 @@
 use core::{
     ptr::null_mut,
-    sync::atomic::{AtomicPtr, AtomicU64, Ordering},
+    sync::atomic::{AtomicBool, AtomicPtr, AtomicU64, Ordering},
 };
 
+use kernel_common::instructions::pause;
+use log::warn;
+
 use crate::{
     cpu::paging::map_physical,
     sys::{
@@ -20,11 +23,38 @@ const REGISTER_TIMER0_CONFIG: usize = 0x20;
 const REGISTER_TIMER0_COMPARATOR: usize = 0x21;
 const CONFIG_ENABLE: u64 = 1;
 const CONFIG_LEGACY_REPLACEMENT: u64 = 2;
+const TIMER_CONFIG_ENABLE: u64 = 4;
 
 static ADDRESS: AtomicPtr<u64> = AtomicPtr::new(null_mut());
 static PERIOD: AtomicU64 = AtomicU64::new(0);
+static EARLY_SLEEP: AtomicBool = AtomicBool::new(false);
 
-fn handler() {}
+fn handler() {
+    if EARLY_SLEEP.load(Ordering::Relaxed) {
+        let address = ADDRESS.load(Ordering::Relaxed);
+        unsafe {
+            let current_config = address.add(REGISTER_TIMER0_CONFIG).read_volatile();
+            address.add(REGISTER_TIMER0_CONFIG).write_volatile(current_config & !TIMER_CONFIG_ENABLE);
+        }
+        EARLY_SLEEP.store(false, Ordering::Relaxed);
+        return;
+    }
+    warn!("Spurious HPET interrupt");
+}
+pub fn early_sleep(ms: usize) {
+    EARLY_SLEEP.store(true, Ordering::Relaxed);
+    unsafe {
+        let address = ADDRESS.load(Ordering::Relaxed);
+        let period = PERIOD.load(Ordering::Relaxed);
+        let current_counter = address.add(REGISTER_COUNTER).read_volatile();
+        address.add(REGISTER_TIMER0_COMPARATOR).write_volatile(current_counter + u64::pow(10, 12) / period * ms as u64);
+        let current_config = address.add(REGISTER_TIMER0_CONFIG).read_volatile();
+        address.add(REGISTER_TIMER0_CONFIG).write_volatile(current_config | TIMER_CONFIG_ENABLE);
+    }
+    while EARLY_SLEEP.load(Ordering::Relaxed) {
+        pause();
+    }
+}
 pub fn setup_hpet() {
     let signature = b"HPET" as *const u8;
     let address;
@@ -42,7 +72,8 @@ pub fn setup_hpet() {
     }
     PERIOD.store(period, Ordering::Relaxed);
     unsafe {
-        address.add(REGISTER_CONFIG).write_volatile(CONFIG_ENABLE | CONFIG_LEGACY_REPLACEMENT);
+        let current_config = address.add(REGISTER_CONFIG).read_volatile();
+        address.add(REGISTER_CONFIG).write_volatile(current_config | CONFIG_ENABLE | CONFIG_LEGACY_REPLACEMENT);
     }
     register_isa_irq_handler(0, handler);
 }
diff --git a/kernel/src/sys/madt.rs b/kernel/src/sys/madt.rs
index b28f1f2..200a7df 100644
--- a/kernel/src/sys/madt.rs
+++ b/kernel/src/sys/madt.rs
@@ -1,4 +1,6 @@
-use core::{arch::asm, mem::size_of};
+use core::mem::size_of;
+
+use kernel_common::instructions::sti;
 
 use crate::sys::acpica_osl::AE_OK;
 
@@ -67,6 +69,6 @@ pub fn parse_madt() {
         subtable_address_i += subtable_header.Length as u64;
     }
     unsafe {
-        asm!("sti");
+        sti();
     }
 }
diff --git a/lib/acpica b/lib/acpica
index 1d9c129..993a257 160000
--- a/lib/acpica
+++ b/lib/acpica
@@ -1 +1 @@
-Subproject commit 1d9c129746c737b68e642f9f29a894e2700fbf46
+Subproject commit 993a25704ac18784b44c1af75cb54abec5141981
diff --git a/lib/kernel-common/src/instructions.rs b/lib/kernel-common/src/instructions.rs
index 28d4d8f..309c42b 100644
--- a/lib/kernel-common/src/instructions.rs
+++ b/lib/kernel-common/src/instructions.rs
@@ -1,10 +1,20 @@
 use core::arch::asm;
 
+pub fn pause() {
+    unsafe {
+        asm!("pause");
+    }
+}
 pub fn cli() {
     unsafe {
         asm!("cli");
     }
 }
+pub unsafe fn sti() {
+    unsafe {
+        asm!("sti");
+    }
+}
 pub fn hlt() {
     unsafe {
         asm!("hlt");