Kernel: Add basic PCI enumeration

kernel/Makefile

@@ -45,6 +45,7 @@ kernel/Input.o					\
 kernel/InterruptController.o	\
 kernel/kernel.o					\
 kernel/kmalloc.o				\
+kernel/PCI.o					\
 kernel/PIC.o					\
 kernel/PIT.o					\
 kernel/RTC.o					\

kernel/include/kernel/PCI.h

@@ -0,0 +1,42 @@
+#pragma once
+
+#include <BAN/Vector.h>
+
+namespace Kernel
+{
+
+	class PCIDevice
+	{
+	public:
+		const uint8_t bus;
+		const uint8_t dev;
+		const uint8_t func;
+
+		const uint8_t class_code;
+		const uint8_t subclass;
+
+		uint32_t read_dword(uint8_t) const;
+		uint16_t read_word(uint8_t) const;
+		uint8_t  read_byte(uint8_t) const;
+	};
+
+	class PCI
+	{
+	public:
+		static bool initialize();
+		static PCI& get();
+		
+		const BAN::Vector<PCIDevice>& devices() const { return m_devices; }
+
+	private:
+		PCI() = default;
+		void check_function(uint8_t bus, uint8_t dev, uint8_t func);
+		void check_device(uint8_t bus, uint8_t dev);
+		void check_bus(uint8_t bus);
+		void check_all_buses();
+
+	private:
+		BAN::Vector<PCIDevice> m_devices;
+	};
+
+}

kernel/kernel/PCI.cpp

@@ -0,0 +1,118 @@
+#include <kernel/Debug.h>
+#include <kernel/IO.h>
+#include <kernel/PCI.h>
+
+#define INVALID 0xFFFF
+#define MULTI_FUNCTION 0x80
+
+#define CONFIG_ADDRESS 0xCF8
+#define CONFIG_DATA 0xCFC
+
+namespace Kernel
+{
+
+	PCI* s_instance = nullptr;
+
+	bool PCI::initialize()
+	{
+		ASSERT(s_instance == nullptr);
+		s_instance = new PCI();
+		ASSERT(s_instance);
+		s_instance->check_all_buses();
+		return !s_instance->m_devices.empty();
+	}
+
+	PCI& PCI::get()
+	{
+		ASSERT(s_instance);
+		return *s_instance;
+	}
+
+	static uint32_t read_config_dword(uint8_t bus, uint8_t dev, uint8_t func, uint8_t offset)
+	{
+		uint32_t config_addr = 0x80000000 | ((uint32_t)bus << 16) | ((uint32_t)dev << 11) | ((uint32_t)func << 8) | offset;
+		IO::outl(CONFIG_ADDRESS, config_addr);
+		return IO::inl(CONFIG_DATA);
+	}
+
+	static uint16_t get_vendor_id(uint8_t bus, uint8_t dev, uint8_t func)
+	{
+		uint32_t dword = read_config_dword(bus, dev, func, 0x00);
+		return dword & 0xFFFF;
+	}
+
+	static uint8_t get_header_type(uint8_t bus, uint8_t dev, uint8_t func)
+	{
+		uint32_t dword = read_config_dword(bus, dev, func, 0x0C);
+		return (dword >> 16) & 0xFF;
+	}
+
+	void PCI::check_function(uint8_t bus, uint8_t dev, uint8_t func)
+	{
+		uint32_t type = read_config_dword(bus, dev, func, 0x08);
+		PCIDevice device {
+			bus,
+			dev,
+			func,
+			(uint8_t)(type >> 24),
+			(uint8_t)(type >> 16),
+		};
+		MUST(m_devices.push_back(BAN::move(device)));
+	}
+
+	void PCI::check_device(uint8_t bus, uint8_t dev)
+	{
+		if (get_vendor_id(bus, dev, 0) == INVALID)
+			return;
+		if (get_header_type(bus, dev, 0) & MULTI_FUNCTION)
+		{
+			for (uint8_t func = 0; func < 8; func++)
+				if (get_vendor_id(bus, dev, func) != INVALID)
+					check_function(bus, dev, func);
+		}
+		else
+		{
+			check_function(bus, dev, 0);
+		}
+	}
+
+	void PCI::check_bus(uint8_t bus)
+	{
+		for (uint8_t dev = 0; dev < 32; dev++)
+			check_device(bus, dev);
+	}
+
+	void PCI::check_all_buses()
+	{
+		if (get_header_type(0, 0, 0) & MULTI_FUNCTION)
+		{
+			for (int func = 0; func < 8; func++)
+				if (get_vendor_id(0, 0, func) != INVALID)
+					check_bus(func);
+		}
+		else
+		{
+			check_bus(0);
+		}
+	}
+
+	uint32_t PCIDevice::read_dword(uint8_t offset) const
+	{
+		ASSERT((offset & 0x03) == 0);
+		return read_config_dword(bus, dev, func, offset);
+	}
+
+	uint16_t PCIDevice::read_word(uint8_t offset) const
+	{
+		ASSERT((offset & 0x01) == 0);
+		uint32_t dword = read_config_dword(bus, dev, func, offset & 0xFC);
+		return (uint16_t)(dword >> (offset & 0x03));
+	}
+
+	uint8_t PCIDevice::read_byte(uint8_t offset) const
+	{
+		uint32_t dword = read_config_dword(bus, dev, func, offset & 0xFC);
+		return (uint8_t)(dword >> (offset & 0x03));
+	}
+
+}