From dcfa93e71f09ca3a6992529790ec8981ce5452f0 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Sat, 13 Jul 2019 20:15:17 +0200
Subject: SB16: Use a snooze alarm to block the current thread while playing.

---
 Kernel/Devices/SB16.cpp | 17 ++++++++++-------
 Kernel/Devices/SB16.h   | 19 +++++++++++++++++++
 2 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/Kernel/Devices/SB16.cpp b/Kernel/Devices/SB16.cpp
index 1e6bc45163..141f01ade3 100644
--- a/Kernel/Devices/SB16.cpp
+++ b/Kernel/Devices/SB16.cpp
@@ -1,5 +1,6 @@
-#include "SB16.h"
-#include "IO.h"
+#include <Kernel/Devices/SB16.h>
+#include <Kernel/IO.h>
+#include <Kernel/Thread.h>
 #include <Kernel/VM/MemoryManager.h>
 
 //#define SB16_DEBUG
@@ -48,6 +49,7 @@ static SB16* s_the;
 SB16::SB16()
     : IRQHandler(5)
     , CharacterDevice(42, 42) // ### ?
+    , m_interrupt_alarm(*this)
 {
     s_the = this;
     initialize();
@@ -141,11 +143,7 @@ void SB16::wait_for_irq()
 #ifdef SB16_DEBUG
     kprintf("SB16: waiting for interrupt...\n");
 #endif
-    // FIXME: Add timeout.
-    while (!m_interrupted) {
-        // FIXME: Put this process into a Blocked state instead, it's stupid to wake up just to check a flag.
-        Scheduler::yield();
-    }
+    current->snooze_until(m_interrupt_alarm);
 #ifdef SB16_DEBUG
     kprintf("SB16: got interrupt!\n");
 #endif
@@ -196,3 +194,8 @@ ssize_t SB16::write(FileDescription&, const u8* data, ssize_t length)
     wait_for_irq();
     return length;
 }
+
+bool SB16InterruptAlarm::is_ringing() const
+{
+    return m_device.got_interrupt({});
+}
diff --git a/Kernel/Devices/SB16.h b/Kernel/Devices/SB16.h
index 20bbb8f6ed..bef47f5f07 100644
--- a/Kernel/Devices/SB16.h
+++ b/Kernel/Devices/SB16.h
@@ -1,11 +1,26 @@
 #pragma once
 
 #include <AK/CircularQueue.h>
+#include <Kernel/Alarm.h>
 #include <Kernel/Devices/CharacterDevice.h>
 #include <Kernel/IRQHandler.h>
 #include <Kernel/VM/PhysicalAddress.h>
 #include <Kernel/VM/PhysicalPage.h>
 
+class SB16;
+
+class SB16InterruptAlarm final : public Alarm {
+public:
+    SB16InterruptAlarm(SB16& device)
+        : m_device(device)
+    {
+    }
+    virtual bool is_ringing() const override;
+
+private:
+    SB16& m_device;
+};
+
 class SB16 final : public IRQHandler
     , public CharacterDevice {
 public:
@@ -20,6 +35,8 @@ public:
     virtual ssize_t write(FileDescription&, const u8*, ssize_t) override;
     virtual bool can_write(FileDescription&) const override { return true; }
 
+    bool got_interrupt(Badge<SB16InterruptAlarm>) const { return m_interrupted; }
+
 private:
     // ^IRQHandler
     virtual void handle_irq() override;
@@ -37,4 +54,6 @@ private:
     RefPtr<PhysicalPage> m_dma_buffer_page;
     bool m_interrupted { false };
     int m_major_version { 0 };
+
+    SB16InterruptAlarm m_interrupt_alarm;
 };
-- 
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