Kernel: Move all Graphics-related code into Devices/GPU directory

Like the HID, Audio and Storage subsystem, the Graphics subsystem (which
handles GPUs technically) exposes unix device files (typically in /dev).
To ensure consistency across the repository, move all related files to a
new directory under Kernel/Devices called "GPU".

Also remove the redundant "GPU" word from the VirtIO driver directory,
and the word "Graphics" from GraphicsManagement.{h,cpp} filenames.

Kernel/Devices/GPU/VirtIO/DisplayConnector.h

@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2021, Sahan Fernando <sahan.h.fernando@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/BinaryBufferWriter.h>
+#include <AK/DistinctNumeric.h>
+#include <Kernel/Devices/CharacterDevice.h>
+#include <Kernel/Devices/GPU/Console/Console.h>
+#include <Kernel/Devices/GPU/DisplayConnector.h>
+#include <Kernel/Devices/GPU/VirtIO/GraphicsAdapter.h>
+#include <Kernel/Devices/GPU/VirtIO/Protocol.h>
+#include <Kernel/Memory/Region.h>
+#include <LibEDID/EDID.h>
+
+namespace Kernel::Graphics::VirtIOGPU {
+
+class Console;
+
+}
+
+namespace Kernel {
+
+class VirtIOGraphicsAdapter;
+class VirtIODisplayConnector final : public DisplayConnector {
+    friend class Graphics::VirtIOGPU::Console;
+    friend class DeviceManagement;
+
+public:
+    static NonnullLockRefPtr<VirtIODisplayConnector> must_create(VirtIOGraphicsAdapter& graphics_adapter, Graphics::VirtIOGPU::ScanoutID scanout_id);
+
+    void set_edid_bytes(Badge<VirtIOGraphicsAdapter>, Array<u8, 128> const& edid_bytes);
+    void set_safe_mode_setting_after_initialization(Badge<VirtIOGraphicsAdapter>);
+    Graphics::VirtIOGPU::ScanoutID scanout_id() const { return m_scanout_id; }
+    Graphics::VirtIOGPU::Protocol::DisplayInfoResponse::Display display_information(Badge<VirtIOGraphicsAdapter>) const;
+
+    void initialize_console(Badge<VirtIOGraphicsAdapter>);
+
+private:
+    virtual bool mutable_mode_setting_capable() const override { return true; }
+    virtual bool double_framebuffering_capable() const override { return false; }
+    virtual bool partial_flush_support() const override { return true; }
+    virtual ErrorOr<void> set_mode_setting(ModeSetting const&) override;
+    virtual ErrorOr<void> set_safe_mode_setting() override;
+    virtual ErrorOr<void> set_y_offset(size_t y) override;
+    virtual ErrorOr<void> unblank() override;
+
+    // Note: VirtIO hardware requires a constant refresh to keep the screen in sync to the user.
+    virtual bool flush_support() const override { return true; }
+    // Note: Paravirtualized hardware doesn't require a defined refresh rate for modesetting.
+    virtual bool refresh_rate_support() const override { return false; }
+
+    virtual ErrorOr<void> flush_first_surface() override;
+    virtual ErrorOr<void> flush_rectangle(size_t buffer_index, FBRect const& rect) override;
+
+    virtual void enable_console() override;
+    virtual void disable_console() override;
+
+    static bool is_valid_buffer_index(size_t buffer_index)
+    {
+        return buffer_index == 0 || buffer_index == 1;
+    }
+
+private:
+    VirtIODisplayConnector(VirtIOGraphicsAdapter& graphics_adapter, Graphics::VirtIOGPU::ScanoutID scanout_id);
+
+    ErrorOr<void> flush_displayed_image(Graphics::VirtIOGPU::Protocol::Rect const& dirty_rect, bool main_buffer);
+    void set_dirty_displayed_rect(Graphics::VirtIOGPU::Protocol::Rect const& dirty_rect, bool main_buffer);
+
+    void clear_to_black();
+
+    // Member data
+    // Context used for kernel operations (e.g. flushing resources to scanout)
+    Graphics::VirtIOGPU::ContextID m_kernel_context_id;
+
+    NonnullLockRefPtr<VirtIOGraphicsAdapter> m_graphics_adapter;
+    LockRefPtr<Graphics::VirtIOGPU::Console> m_console;
+    Graphics::VirtIOGPU::Protocol::DisplayInfoResponse::Display m_display_info {};
+    Graphics::VirtIOGPU::ScanoutID m_scanout_id;
+
+    constexpr static size_t NUM_TRANSFER_REGION_PAGES = 256;
+};
+
+}