USB: Further Implement USB Structures

These are the actual structures that allow USB to work (i.e the ones
actually defined in the specification). This should provide us enough
of a baseline implementation that we can build on to support
different types of USB device.

Kernel/Devices/USB/USBDevice.h

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2021, Jesse Buhagiar <jooster669@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/OwnPtr.h>
+#include <AK/Types.h>
+#include <Kernel/Devices/USB/USBPipe.h>
+
+namespace Kernel::USB {
+
+//
+// Some nice info from FTDI on device enumeration and how some of this
+// glues together:
+//
+// https://www.ftdichip.com/Support/Documents/TechnicalNotes/TN_113_Simplified%20Description%20of%20USB%20Device%20Enumeration.pdf
+class Device {
+public:
+    enum class PortNumber : u8 {
+        Port1 = 0,
+        Port2
+    };
+
+    enum class DeviceSpeed : u8 {
+        FullSpeed = 0,
+        LowSpeed
+    };
+
+public:
+    static KResultOr<NonnullOwnPtr<Device>> try_create(PortNumber, DeviceSpeed);
+    static Device* get(PortNumber);
+
+    Device(PortNumber, DeviceSpeed, NonnullOwnPtr<Pipe> default_pipe);
+    ~Device();
+
+    KResult enumerate();
+
+    PortNumber port() const { return m_device_port; }
+    DeviceSpeed speed() const { return m_device_speed; }
+
+    u8 address() const { return m_address; }
+
+private:
+private:
+    PortNumber m_device_port;   // What port is this device attached to
+    DeviceSpeed m_device_speed; // What speed is this device running at
+    u8 m_address { 0 };         // USB address assigned to this device
+
+    // Device description
+    u16 m_vendor_id { 0 };  // This device's vendor ID assigned by the USB group
+    u16 m_product_id { 0 }; // This device's product ID assigned by the USB group
+
+    NonnullOwnPtr<Pipe> m_default_pipe; // Default communication pipe (endpoint0) used during enumeration
+};
+}