Rearrange AHCI code, attempt to read WIP

src/kernel/ahci/hba.h

@@ -0,0 +1,31 @@
+#pragma once
+/// \file hba.h
+/// Definition for AHCI host bus adapters
+#include "kutil/vector.h"
+#include "ahci/port.h"
+
+class pci_device;
+
+
+namespace ahci {
+
+enum class hba_cap : uint32_t;
+enum class hba_cap2 : uint32_t;
+struct hba_data;
+
+
+/// An AHCI host bus adapter
+class hba
+{
+public:
+	/// Constructor.
+	/// \arg device  The PCI device for this HBA
+	hba(pci_device *device);
+
+private:
+	pci_device *m_device;
+	hba_data *m_data;
+	kutil::vector<port> m_ports;
+};
+
+} // namespace ahci