Kernel: Move x86-specific HID code to the Arch/x86 directory

The i8042 controller with its attached devices, the PS2 keyboard and
mouse, rely on x86-specific IO instructions to work. Therefore, move
them to the Arch/x86 directory to make it easier to omit the handling
code of these devices.

Kernel/Arch/x86/ISABus/HID/PS2MouseDevice.h

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/CircularQueue.h>
+#include <Kernel/API/MousePacket.h>
+#include <Kernel/Arch/x86/ISABus/I8042Controller.h>
+#include <Kernel/Devices/HID/MouseDevice.h>
+#include <Kernel/Interrupts/IRQHandler.h>
+#include <Kernel/Random.h>
+
+namespace Kernel {
+class PS2MouseDevice : public IRQHandler
+    , public MouseDevice
+    , public I8042Device {
+    friend class DeviceManagement;
+
+public:
+    static ErrorOr<NonnullLockRefPtr<PS2MouseDevice>> try_to_initialize(I8042Controller const&);
+    ErrorOr<void> initialize();
+
+    virtual ~PS2MouseDevice() override;
+
+    virtual StringView purpose() const override { return class_name(); }
+
+    // ^I8042Device
+    virtual void irq_handle_byte_read(u8 byte) override;
+    virtual void enable_interrupts() override
+    {
+        enable_irq();
+    }
+
+protected:
+    explicit PS2MouseDevice(I8042Controller const&);
+
+    // ^IRQHandler
+    virtual bool handle_irq(RegisterState const&) override;
+
+    struct RawPacket {
+        union {
+            u32 dword;
+            u8 bytes[4];
+        };
+    };
+
+    ErrorOr<u8> read_from_device();
+    ErrorOr<u8> send_command(u8 command);
+    ErrorOr<u8> send_command(u8 command, u8 data);
+    MousePacket parse_data_packet(RawPacket const&);
+    ErrorOr<void> set_sample_rate(u8);
+    ErrorOr<u8> get_device_id();
+
+    u8 m_data_state { 0 };
+    RawPacket m_data;
+    bool m_has_wheel { false };
+    bool m_has_five_buttons { false };
+};
+
+}