Kernel: Add very simple BGA driver

Only thing this is currently helpful is qemu when booting with -kernel
flag as that does not provide framebuffer info in multiboot headers

kernel/include/kernel/Device/FramebufferDevice.h

@@ -6,15 +6,22 @@
 namespace Kernel
 {
 
+	class BGAController;
+
 	class FramebufferDevice : public CharacterDevice
 	{
 	public:
+		static BAN::ErrorOr<BAN::RefPtr<FramebufferDevice>> create(paddr_t paddr, uint32_t width, uint32_t height, uint32_t pitch, uint8_t bpp);
+		static BAN::ErrorOr<BAN::RefPtr<FramebufferDevice>> create(BAN::RefPtr<BGAController>);
 		static BAN::ErrorOr<BAN::RefPtr<FramebufferDevice>> create_from_boot_framebuffer();
 		static BAN::RefPtr<FramebufferDevice> boot_framebuffer();
 		~FramebufferDevice();
 
 		uint32_t width() const { return m_width; }
 		uint32_t height() const { return m_height; }
+		uint8_t bpp() const { return m_bpp; }
+
+		BAN::ErrorOr<void> set_bga_controller(BAN::RefPtr<BGAController>);
 
 		uint32_t get_pixel(uint32_t x, uint32_t y) const;
 		void set_pixel(uint32_t x, uint32_t y, uint32_t rgb);
@@ -50,14 +57,16 @@ namespace Kernel
 	private:
 		const BAN::String m_name;
 
-		vaddr_t			m_video_memory_vaddr { 0 };
-		const paddr_t	m_video_memory_paddr;
-		const uint32_t	m_width;
-		const uint32_t	m_height;
-		const uint32_t	m_pitch;
-		const uint8_t	m_bpp;
+		vaddr_t m_video_memory_vaddr { 0 };
+		paddr_t m_video_memory_paddr { 0 };
+
+		uint32_t m_width  { 0 };
+		uint32_t m_height { 0 };
+		uint32_t m_pitch  { 0 };
+		uint8_t  m_bpp    { 0 };
 
 		BAN::UniqPtr<VirtualRange> m_video_buffer;
+		BAN::RefPtr<BGAController> m_bga_controller;
 
 		friend class FramebufferMemoryRegion;
 	};

kernel/include/kernel/Graphics/BGA.h

@@ -0,0 +1,37 @@
+#pragma once
+
+#include <BAN/RefPtr.h>
+#include <kernel/Lock/SpinLock.h>
+#include <kernel/PCI.h>
+
+#include <sys/framebuffer.h>
+
+namespace Kernel
+{
+
+	class BGAController : public BAN::RefCounted<BGAController>
+	{
+	public:
+		static BAN::ErrorOr<BAN::RefPtr<BGAController>> create(PCI::Device&);
+
+		fb_fix_info get_fb_fix_info() const;
+		fb_var_info get_fb_var_info() const;
+		BAN::ErrorOr<void> set_fb_var_info(const fb_var_info&);
+
+	private:
+		BGAController(PCI::Device&);
+		BAN::ErrorOr<void> initialize();
+
+		void write_reg(uint16_t reg, uint16_t value);
+		uint16_t read_reg(uint16_t reg);
+
+	private:
+		mutable RecursiveSpinLock m_lock;
+		PCI::Device& m_pci_device;
+		BAN::UniqPtr<PCI::BarRegion> m_lfb_bar;
+
+		fb_fix_info m_fix_info {};
+		fb_var_info m_var_info {};
+	};
+
+}

kernel/include/kernel/Terminal/TTY.h

@@ -53,6 +53,8 @@ namespace Kernel
 
 		virtual bool master_has_closed() const { return false; }
 
+		virtual bool is_vtty() const { return false; }
+
 	protected:
 		TTY(termios termios, mode_t mode, uid_t uid, gid_t gid);
 

kernel/include/kernel/Terminal/VirtualTTY.h

@@ -21,6 +21,7 @@ namespace Kernel
 
 		void clear() override;
 
+		bool is_vtty() const override { return true; }
 		BAN::ErrorOr<void> set_terminal_driver(BAN::RefPtr<TerminalDriver>);
 
 	protected: