Kernel: Implement basic AC97 driver

kernel/include/kernel/Audio/Controller.h

@@ -0,0 +1,48 @@
+#pragma once
+
+#include <kernel/Device/Device.h>
+#include <kernel/PCI.h>
+
+namespace Kernel
+{
+
+	class AudioController : public CharacterDevice
+	{
+	public:
+		static BAN::ErrorOr<BAN::RefPtr<AudioController>> create(PCI::Device& pci_device);
+
+		dev_t rdev() const override { return m_rdev; }
+		BAN::StringView name() const override { return m_name; }
+
+	protected:
+		AudioController();
+
+		virtual void handle_new_data() = 0;
+
+		virtual uint32_t get_channels() const = 0;
+		virtual uint32_t get_sample_rate() const = 0;
+
+		bool can_read_impl() const override { return false; }
+		bool can_write_impl() const override { SpinLockGuard _(m_spinlock); return m_sample_data_size < m_sample_data_capacity; }
+		bool has_error_impl() const override { return false; }
+		bool has_hungup_impl() const override { return false; }
+
+		BAN::ErrorOr<size_t> write_impl(off_t, BAN::ConstByteSpan) override;
+
+		BAN::ErrorOr<long> ioctl_impl(int cmd, void* arg) override;
+
+	protected:
+		ThreadBlocker m_sample_data_blocker;
+		mutable SpinLock m_spinlock;
+
+		static constexpr size_t m_sample_data_capacity = 1 << 20;
+		uint8_t m_sample_data[m_sample_data_capacity];
+		size_t m_sample_data_head { 0 };
+		size_t m_sample_data_size { 0 };
+
+	private:
+		const dev_t m_rdev;
+		char m_name[10] {};
+	};
+
+}