Kernel: Create support for PCI ECAM

The new PCI subsystem is initialized during runtime.
PCI::Initializer is supposed to be called during early boot, to
perform a few tests, and initialize the proper configuration space
access mechanism. Kernel boot parameters can be specified by a user to
determine what tests will occur, to aid debugging on problematic
machines.
After that, PCI::Initializer should be dismissed.

PCI::IOAccess is a class that is derived from PCI::Access
class and implements PCI configuration space access mechanism via x86
IO ports.
PCI::MMIOAccess is a class that is derived from PCI::Access
and implements PCI configurtaion space access mechanism via memory
access.

The new PCI subsystem also supports determination of IO/MMIO space
needed by a device by checking a given BAR.
In addition, Every device or component that use the PCI subsystem has
changed to match the last changes.

18 files changed, 873 insertions, 12 deletions

diff --git a/Kernel/Devices/BXVGADevice.cpp b/Kernel/Devices/BXVGADevice.cpp
index a45305f1d6..5da0b771f7 100644
--- a/Kernel/Devices/BXVGADevice.cpp
+++ b/Kernel/Devices/BXVGADevice.cpp
@@ -1,6 +1,6 @@
 #include <Kernel/Devices/BXVGADevice.h>
 #include <Kernel/IO.h>
-#include <Kernel/PCI.h>
+#include <Kernel/PCI/Access.h>
 #include <Kernel/Process.h>
 #include <Kernel/VM/AnonymousVMObject.h>
 #include <Kernel/VM/MemoryManager.h>
diff --git a/Kernel/Devices/PATAChannel.h b/Kernel/Devices/PATAChannel.h
index da1cb95421..6db5953b44 100644
--- a/Kernel/Devices/PATAChannel.h
+++ b/Kernel/Devices/PATAChannel.h
@@ -14,7 +14,7 @@
 #include <AK/RefPtr.h>
 #include <Kernel/IRQHandler.h>
 #include <Kernel/Lock.h>
-#include <Kernel/PCI.h>
+#include <Kernel/PCI/Access.h>
 #include <Kernel/VM/PhysicalAddress.h>
 #include <Kernel/VM/PhysicalPage.h>
 #include <Kernel/WaitQueue.h>
diff --git a/Kernel/FileSystem/ProcFS.cpp b/Kernel/FileSystem/ProcFS.cpp
index 0c97e47611..b75db41862 100644
--- a/Kernel/FileSystem/ProcFS.cpp
+++ b/Kernel/FileSystem/ProcFS.cpp
@@ -22,7 +22,7 @@
 #include <Kernel/Net/Routing.h>
 #include <Kernel/Net/TCPSocket.h>
 #include <Kernel/Net/UDPSocket.h>
-#include <Kernel/PCI.h>
+#include <Kernel/PCI/Access.h>
 #include <Kernel/Profiling.h>
 #include <Kernel/VM/MemoryManager.h>
 #include <Kernel/VM/PurgeableVMObject.h>
@@ -289,6 +289,7 @@ Optional<KBuffer> procfs$pci(InodeIdentifier)
     JsonArraySerializer array { builder };
     PCI::enumerate_all([&array](PCI::Address address, PCI::ID id) {
         auto obj = array.add_object();
+        obj.add("seg", address.seg());
         obj.add("bus", address.bus());
         obj.add("slot", address.slot());
         obj.add("function", address.function());
diff --git a/Kernel/Makefile b/Kernel/Makefile
index 1473108265..53fedf078f 100644
--- a/Kernel/Makefile
+++ b/Kernel/Makefile
@@ -71,7 +71,10 @@ OBJS = \
     Net/Socket.o \
     Net/TCPSocket.o \
     Net/UDPSocket.o \
-    PCI.o \
+    PCI/Access.o \
+    PCI/IOAccess.o \
+    PCI/MMIOAccess.o \
+    PCI/Initializer.o \
     Process.o \
     ProcessTracer.o \
     Profiling.o \
@@ -97,6 +100,10 @@ OBJS = \
     VM/RangeAllocator.o \
     VM/Region.o \
     VM/VMObject.o \
+    ACPI/ACPIParser.o \
+    ACPI/ACPIStaticParser.o \
+    ACPI/ACPIDynamicParser.o \
+    ACPI/DMIDecoder.o \
     WaitQueue.o \
     init.o \
     kprintf.o
diff --git a/Kernel/Net/E1000NetworkAdapter.cpp b/Kernel/Net/E1000NetworkAdapter.cpp
index ff9ee3f538..d35cec36ce 100644
--- a/Kernel/Net/E1000NetworkAdapter.cpp
+++ b/Kernel/Net/E1000NetworkAdapter.cpp
@@ -1,6 +1,5 @@
 #include <Kernel/IO.h>
 #include <Kernel/Net/E1000NetworkAdapter.h>
-#include <Kernel/PCI.h>
 #include <Kernel/Thread.h>
 
 #define REG_CTRL 0x0000
@@ -119,6 +118,7 @@ E1000NetworkAdapter::E1000NetworkAdapter(PCI::Address pci_address, u8 irq)
     enable_bus_mastering(m_pci_address);
 
     m_mmio_base = PhysicalAddress(PCI::get_BAR0(m_pci_address));
+    u32 mmio_base_size = PCI::get_BAR_Space_Size(pci_address, 0);
     MM.map_for_kernel(VirtualAddress(m_mmio_base.get()), m_mmio_base);
     MM.map_for_kernel(VirtualAddress(m_mmio_base.offset(4096).get()), m_mmio_base.offset(4096));
     MM.map_for_kernel(VirtualAddress(m_mmio_base.offset(8192).get()), m_mmio_base.offset(8192));
@@ -129,6 +129,7 @@ E1000NetworkAdapter::E1000NetworkAdapter(PCI::Address pci_address, u8 irq)
     m_interrupt_line = PCI::get_interrupt_line(m_pci_address);
     kprintf("E1000: IO port base: %w\n", m_io_base);
     kprintf("E1000: MMIO base: P%x\n", m_mmio_base);
+    kprintf("E1000: MMIO base size: %u bytes\n", mmio_base_size);
     kprintf("E1000: Interrupt line: %u\n", m_interrupt_line);
     detect_eeprom();
     kprintf("E1000: Has EEPROM? %u\n", m_has_eeprom);
diff --git a/Kernel/Net/E1000NetworkAdapter.h b/Kernel/Net/E1000NetworkAdapter.h
index a437feda26..b1c99e5774 100644
--- a/Kernel/Net/E1000NetworkAdapter.h
+++ b/Kernel/Net/E1000NetworkAdapter.h
@@ -3,7 +3,7 @@
 #include <AK/OwnPtr.h>
 #include <Kernel/IRQHandler.h>
 #include <Kernel/Net/NetworkAdapter.h>
-#include <Kernel/PCI.h>
+#include <Kernel/PCI/Access.h>
 
 class E1000NetworkAdapter final : public NetworkAdapter
     , public IRQHandler {
diff --git a/Kernel/Net/RTL8139NetworkAdapter.cpp b/Kernel/Net/RTL8139NetworkAdapter.cpp
index 5ab7282430..5b29750d59 100644
--- a/Kernel/Net/RTL8139NetworkAdapter.cpp
+++ b/Kernel/Net/RTL8139NetworkAdapter.cpp
@@ -1,6 +1,5 @@
 #include <Kernel/IO.h>
 #include <Kernel/Net/RTL8139NetworkAdapter.h>
-#include <Kernel/PCI.h>
 
 //#define RTL8139_DEBUG
 
diff --git a/Kernel/Net/RTL8139NetworkAdapter.h b/Kernel/Net/RTL8139NetworkAdapter.h
index 7724f18289..77071db4b9 100644
--- a/Kernel/Net/RTL8139NetworkAdapter.h
+++ b/Kernel/Net/RTL8139NetworkAdapter.h
@@ -3,7 +3,7 @@
 #include <AK/OwnPtr.h>
 #include <Kernel/IRQHandler.h>
 #include <Kernel/Net/NetworkAdapter.h>
-#include <Kernel/PCI.h>
+#include <Kernel/PCI/Access.h>
 
 #define RTL8139_TX_BUFFER_COUNT 4
 
diff --git a/Kernel/PCI/Access.cpp b/Kernel/PCI/Access.cpp
new file mode 100644
index 0000000000..6e342027f8
--- /dev/null
+++ b/Kernel/PCI/Access.cpp
@@ -0,0 +1,142 @@
+#include <Kernel/PCI/Access.h>
+#include <Kernel/PCI/IOAccess.h>
+
+static PCI::Access* s_access;
+
+PCI::Access& PCI::Access::the()
+{
+    if (s_access == nullptr) {
+        ASSERT_NOT_REACHED(); // We failed to initialize the PCI subsystem, so stop here!
+    }
+    return *s_access;
+}
+
+bool PCI::Access::is_initialized()
+{
+    return (s_access != nullptr);
+}
+
+PCI::Access::Access()
+{
+    s_access = this;
+}
+
+void PCI::Access::enumerate_functions(int type, u8 bus, u8 slot, u8 function, Function<void(Address, ID)>& callback)
+{
+    Address address(0, bus, slot, function);
+    if (type == -1 || type == read_type(address))
+        callback(address, { read16_field(address, PCI_VENDOR_ID), read16_field(address, PCI_DEVICE_ID) });
+    if (read_type(address) == PCI_TYPE_BRIDGE) {
+        u8 secondary_bus = read8_field(address, PCI_SECONDARY_BUS);
+#ifdef PCI_DEBUG
+        kprintf("PCI: Found secondary bus: %u\n", secondary_bus);
+#endif
+        ASSERT(secondary_bus != bus);
+        enumerate_bus(type, secondary_bus, callback);
+    }
+}
+
+void PCI::Access::enumerate_slot(int type, u8 bus, u8 slot, Function<void(Address, ID)>& callback)
+{
+    Address address(0, bus, slot, 0);
+    if (read16_field(address, PCI_VENDOR_ID) == PCI_NONE)
+        return;
+    enumerate_functions(type, bus, slot, 0, callback);
+    if (!(read8_field(address, PCI_HEADER_TYPE) & 0x80))
+        return;
+    for (u8 function = 1; function < 8; ++function) {
+        Address address(0, bus, slot, function);
+        if (read16_field(address, PCI_VENDOR_ID) != PCI_NONE)
+            enumerate_functions(type, bus, slot, function, callback);
+    }
+}
+
+void PCI::Access::enumerate_bus(int type, u8 bus, Function<void(Address, ID)>& callback)
+{
+    for (u8 slot = 0; slot < 32; ++slot)
+        enumerate_slot(type, bus, slot, callback);
+}
+
+void PCI::Access::enable_bus_mastering(Address address)
+{
+    auto value = read16_field(address, PCI_COMMAND);
+    value |= (1 << 2);
+    value |= (1 << 0);
+    write16_field(address, PCI_COMMAND, value);
+}
+
+void PCI::Access::disable_bus_mastering(Address address)
+{
+    auto value = read16_field(address, PCI_COMMAND);
+    value &= ~(1 << 2);
+    value |= (1 << 0);
+    write16_field(address, PCI_COMMAND, value);
+}
+
+namespace PCI {
+void enumerate_all(Function<void(Address, ID)> callback)
+{
+    PCI::Access::the().enumerate_all(callback);
+}
+
+u8 get_interrupt_line(Address address)
+{
+    return PCI::Access::the().get_interrupt_line(address);
+}
+u32 get_BAR0(Address address)
+{
+    return PCI::Access::the().get_BAR0(address);
+}
+u32 get_BAR1(Address address)
+{
+    return PCI::Access::the().get_BAR1(address);
+}
+u32 get_BAR2(Address address)
+{
+    return PCI::Access::the().get_BAR2(address);
+}
+u32 get_BAR3(Address address)
+{
+    return PCI::Access::the().get_BAR3(address);
+}
+u32 get_BAR4(Address address)
+{
+    return PCI::Access::the().get_BAR4(address);
+}
+u32 get_BAR5(Address address)
+{
+    return PCI::Access::the().get_BAR5(address);
+}
+u8 get_revision_id(Address address)
+{
+    return PCI::Access::the().get_revision_id(address);
+}
+u8 get_subclass(Address address)
+{
+    return PCI::Access::the().get_subclass(address);
+}
+u8 get_class(Address address)
+{
+    return PCI::Access::the().get_class(address);
+}
+u16 get_subsystem_id(Address address)
+{
+    return PCI::Access::the().get_subsystem_id(address);
+}
+u16 get_subsystem_vendor_id(Address address)
+{
+    return PCI::Access::the().get_subsystem_vendor_id(address);
+}
+void enable_bus_mastering(Address address)
+{
+    PCI::Access::the().enable_bus_mastering(address);
+}
+void disable_bus_mastering(Address address)
+{
+    PCI::Access::the().disable_bus_mastering(address);
+}
+u32 get_BAR_Space_Size(Address address, u8 bar_number)
+{
+    return PCI::Access::the().get_BAR_Space_Size(address, bar_number);
+}
+}
diff --git a/Kernel/PCI/Access.h b/Kernel/PCI/Access.h
new file mode 100644
index 0000000000..d2f7cdc053
--- /dev/null
+++ b/Kernel/PCI/Access.h
@@ -0,0 +1,62 @@
+#pragma once
+
+#include <AK/String.h>
+#include <Kernel/PCI/Definitions.h>
+
+class PCI::Access {
+public:
+    virtual void enumerate_all(Function<void(Address, ID)>&) = 0;
+    virtual u8 get_interrupt_line(Address address) { return read8_field(address, PCI_INTERRUPT_LINE); }
+    virtual u32 get_BAR0(Address address) { return read32_field(address, PCI_BAR0); }
+    virtual u32 get_BAR1(Address address) { return read32_field(address, PCI_BAR1); }
+    virtual u32 get_BAR2(Address address) { return read32_field(address, PCI_BAR2); }
+    virtual u32 get_BAR3(Address address) { return read32_field(address, PCI_BAR3); }
+    virtual u32 get_BAR4(Address address) { return read32_field(address, PCI_BAR4); }
+    virtual u32 get_BAR5(Address address) { return read32_field(address, PCI_BAR5); }
+
+    virtual u32 get_BAR_Space_Size(Address address, u8 bar_number)
+    {
+        // See PCI Spec 2.3, Page 222
+        ASSERT(bar_number < 6);
+        u8 field = (PCI_BAR0 + (bar_number << 2));
+        u32 bar_reserved = read32_field(address, field);
+        write32_field(address, field, 0xFFFFFFFF);
+        u32 space_size = read32_field(address, field);
+        write32_field(address, field, bar_reserved);
+        space_size &= 0xfffffff0;
+        space_size = (~space_size) + 1;
+        return space_size;
+    }
+
+    virtual u8 get_revision_id(Address address) { return read8_field(address, PCI_REVISION_ID); }
+    virtual u8 get_subclass(Address address) { return read8_field(address, PCI_SUBCLASS); }
+    virtual u8 get_class(Address address) { return read8_field(address, PCI_CLASS); }
+    virtual u16 get_subsystem_id(Address address) { return read16_field(address, PCI_SUBSYSTEM_ID); }
+    virtual u16 get_subsystem_vendor_id(Address address) { return read16_field(address, PCI_SUBSYSTEM_VENDOR_ID); }
+    virtual u16 read_type(Address address) { return (read8_field(address, PCI_CLASS) << 8u) | read8_field(address, PCI_SUBCLASS); }
+
+    virtual void enable_bus_mastering(Address) final;
+    virtual void disable_bus_mastering(Address) final;
+
+    virtual void enumerate_bus(int type, u8 bus, Function<void(Address, ID)>&) final;
+    virtual void enumerate_functions(int type, u8 bus, u8 slot, u8 function, Function<void(Address, ID)>& callback) final;
+    virtual void enumerate_slot(int type, u8 bus, u8 slot, Function<void(Address, ID)>& callback) final;
+
+    static Access& the();
+    static bool is_initialized();
+    virtual uint32_t get_segments_count() = 0;
+    virtual uint8_t get_segment_start_bus(u32 segment) = 0;
+    virtual uint8_t get_segment_end_bus(u32 segment) = 0;
+    virtual String get_access_type() = 0;
+
+protected:
+    Access();
+
+    virtual u8 read8_field(Address address, u32 field) = 0;
+    virtual u16 read16_field(Address address, u32 field) = 0;
+    virtual u32 read32_field(Address address, u32 field) = 0;
+
+    virtual void write8_field(Address address, u32 field, u8 value) = 0;
+    virtual void write16_field(Address address, u32 field, u16 value) = 0;
+    virtual void write32_field(Address address, u32 field, u32 value) = 0;
+};
diff --git a/Kernel/PCI/Definitions.h b/Kernel/PCI/Definitions.h
new file mode 100644
index 0000000000..e2954b05ef
--- /dev/null
+++ b/Kernel/PCI/Definitions.h
@@ -0,0 +1,113 @@
+#pragma once
+
+#include <AK/Function.h>
+#include <AK/Types.h>
+
+#define PCI_VENDOR_ID 0x00           // word
+#define PCI_DEVICE_ID 0x02           // word
+#define PCI_COMMAND 0x04             // word
+#define PCI_STATUS 0x06              // word
+#define PCI_REVISION_ID 0x08         // byte
+#define PCI_PROG_IF 0x09             // byte
+#define PCI_SUBCLASS 0x0a            // byte
+#define PCI_CLASS 0x0b               // byte
+#define PCI_CACHE_LINE_SIZE 0x0c     // byte
+#define PCI_LATENCY_TIMER 0x0d       // byte
+#define PCI_HEADER_TYPE 0x0e         // byte
+#define PCI_BIST 0x0f                // byte
+#define PCI_BAR0 0x10                // u32
+#define PCI_BAR1 0x14                // u32
+#define PCI_BAR2 0x18                // u32
+#define PCI_BAR3 0x1C                // u32
+#define PCI_BAR4 0x20                // u32
+#define PCI_BAR5 0x24                // u32
+#define PCI_SUBSYSTEM_ID 0x2C        // u16
+#define PCI_SUBSYSTEM_VENDOR_ID 0x2E // u16
+#define PCI_INTERRUPT_LINE 0x3C      // byte
+#define PCI_SECONDARY_BUS 0x19       // byte
+#define PCI_HEADER_TYPE_DEVICE 0
+#define PCI_HEADER_TYPE_BRIDGE 1
+#define PCI_TYPE_BRIDGE 0x0604
+#define PCI_ADDRESS_PORT 0xCF8
+#define PCI_VALUE_PORT 0xCFC
+#define PCI_NONE 0xFFFF
+#define PCI_MAX_DEVICES_PER_BUS 32
+#define PCI_MAX_BUSES 256
+#define PCI_MAX_FUNCTIONS_PER_DEVICE 8
+
+//#define PCI_DEBUG 1
+
+namespace PCI {
+struct ID {
+    u16 vendor_id { 0 };
+    u16 device_id { 0 };
+
+    bool is_null() const { return !vendor_id && !device_id; }
+
+    bool operator==(const ID& other) const
+    {
+        return vendor_id == other.vendor_id && device_id == other.device_id;
+    }
+};
+
+struct Address {
+    Address() {}
+    Address(u16 seg)
+        : m_seg(seg)
+        , m_bus(0)
+        , m_slot(0)
+        , m_function(0)
+    {
+    }
+    Address(u16 seg, u8 bus, u8 slot, u8 function)
+        : m_seg(seg)
+        , m_bus(bus)
+        , m_slot(slot)
+        , m_function(function)
+    {
+    }
+
+    bool is_null() const { return !m_bus && !m_slot && !m_function; }
+    operator bool() const { return !is_null(); }
+
+    u16 seg() const { return m_seg; }
+    u8 bus() const { return m_bus; }
+    u8 slot() const { return m_slot; }
+    u8 function() const { return m_function; }
+
+    u32 io_address_for_field(u8 field) const
+    {
+        return 0x80000000u | (m_bus << 16u) | (m_slot << 11u) | (m_function << 8u) | (field & 0xfc);
+    }
+
+private:
+    u32 m_seg { 0 };
+    u8 m_bus { 0 };
+    u8 m_slot { 0 };
+    u8 m_function { 0 };
+};
+
+void enumerate_all(Function<void(Address, ID)> callback);
+u8 get_interrupt_line(Address);
+u32 get_BAR0(Address);
+u32 get_BAR1(Address);
+u32 get_BAR2(Address);
+u32 get_BAR3(Address);
+u32 get_BAR4(Address);
+u32 get_BAR5(Address);
+u8 get_revision_id(Address);
+u8 get_subclass(Address);
+u8 get_class(Address);
+u16 get_subsystem_id(Address);
+u16 get_subsystem_vendor_id(Address);
+u32 get_BAR_Space_Size(Address, u8);
+void enable_bus_mastering(Address);
+void disable_bus_mastering(Address);
+
+class Initializer;
+class Access;
+class MMIOAccess;
+class IOAccess;
+class MMIOSegment;
+
+}
diff --git a/Kernel/PCI/IOAccess.cpp b/Kernel/PCI/IOAccess.cpp
new file mode 100644
index 0000000000..20c92bfe00
--- /dev/null
+++ b/Kernel/PCI/IOAccess.cpp
@@ -0,0 +1,63 @@
+#include <Kernel/IO.h>
+#include <Kernel/PCI/IOAccess.h>
+
+void PCI::IOAccess::initialize()
+{
+    if (!PCI::Access::is_initialized())
+        new PCI::IOAccess();
+}
+
+PCI::IOAccess::IOAccess()
+{
+    kprintf("PCI: Using IO Mechanism for PCI Configuartion Space Access\n");
+}
+
+u8 PCI::IOAccess::read8_field(Address address, u32 field)
+{
+    IO::out32(PCI_ADDRESS_PORT, address.io_address_for_field(field));
+    return IO::in8(PCI_VALUE_PORT + (field & 3));
+}
+
+u16 PCI::IOAccess::read16_field(Address address, u32 field)
+{
+    IO::out32(PCI_ADDRESS_PORT, address.io_address_for_field(field));
+    return IO::in16(PCI_VALUE_PORT + (field & 2));
+}
+
+u32 PCI::IOAccess::read32_field(Address address, u32 field)
+{
+    IO::out32(PCI_ADDRESS_PORT, address.io_address_for_field(field));
+    return IO::in32(PCI_VALUE_PORT);
+}
+
+void PCI::IOAccess::write8_field(Address address, u32 field, u8 value)
+{
+    IO::out32(PCI_ADDRESS_PORT, address.io_address_for_field(field));
+    IO::out8(PCI_VALUE_PORT + (field & 3), value);
+}
+void PCI::IOAccess::write16_field(Address address, u32 field, u16 value)
+{
+    IO::out32(PCI_ADDRESS_PORT, address.io_address_for_field(field));
+    IO::out16(PCI_VALUE_PORT + (field & 2), value);
+}
+void PCI::IOAccess::write32_field(Address address, u32 field, u32 value)
+{
+    IO::out32(PCI_ADDRESS_PORT, address.io_address_for_field(field));
+    IO::out32(PCI_VALUE_PORT, value);
+}
+
+void PCI::IOAccess::enumerate_all(Function<void(Address, ID)>& callback)
+{
+    // Single PCI host controller.
+    if ((read8_field(Address(), PCI_HEADER_TYPE) & 0x80) == 0) {
+        enumerate_bus(-1, 0, callback);
+        return;
+    }
+
+    // Multiple PCI host controllers.
+    for (u8 function = 0; function < 8; ++function) {
+        if (read16_field(Address(0, 0, 0, function), PCI_VENDOR_ID) == PCI_NONE)
+            break;
+        enumerate_bus(-1, function, callback);
+    }
+}
diff --git a/Kernel/PCI/IOAccess.h b/Kernel/PCI/IOAccess.h
new file mode 100644
index 0000000000..d132a6fe40
--- /dev/null
+++ b/Kernel/PCI/IOAccess.h
@@ -0,0 +1,25 @@
+#pragma once
+#include <Kernel/PCI/Access.h>
+
+class PCI::IOAccess final : public PCI::Access {
+public:
+    static void initialize();
+    virtual void enumerate_all(Function<void(Address, ID)>&) override final;
+
+    virtual String get_access_type() override final { return "IO-Access"; };
+
+protected:
+    IOAccess();
+
+private:
+    virtual u8 read8_field(Address address, u32) override final;
+    virtual u16 read16_field(Address address, u32) override final;
+    virtual u32 read32_field(Address address, u32) override final;
+    virtual void write8_field(Address address, u32, u8) override final;
+    virtual void write16_field(Address address, u32, u16) override final;
+    virtual void write32_field(Address address, u32, u32) override final;
+
+    virtual uint32_t get_segments_count() { return 1; };
+    virtual uint8_t get_segment_start_bus(u32) { return 0x0; };
+    virtual uint8_t get_segment_end_bus(u32) { return 0xFF; };
+};
\ No newline at end of file
diff --git a/Kernel/PCI/Initializer.cpp b/Kernel/PCI/Initializer.cpp
new file mode 100644
index 0000000000..40020f64cb
--- /dev/null
+++ b/Kernel/PCI/Initializer.cpp
@@ -0,0 +1,126 @@
+#include <Kernel/ACPI/ACPIParser.h>
+#include <Kernel/ACPI/DMIDecoder.h>
+#include <Kernel/IO.h>
+#include <Kernel/KParams.h>
+#include <Kernel/PCI/IOAccess.h>
+#include <Kernel/PCI/Initializer.h>
+#include <Kernel/PCI/MMIOAccess.h>
+
+static PCI::Initializer* s_pci_initializer;
+
+PCI::Initializer& PCI::Initializer::the()
+{
+    if (s_pci_initializer == nullptr) {
+        s_pci_initializer = new PCI::Initializer();
+    }
+    return *s_pci_initializer;
+}
+void PCI::Initializer::initialize_pci_mmio_access(ACPI_RAW::MCFG& mcfg)
+{
+    PCI::MMIOAccess::initialize(mcfg);
+}
+void PCI::Initializer::initialize_pci_io_access()
+{
+    PCI::IOAccess::initialize();
+}
+void PCI::Initializer::test_and_initialize(bool disable_pci_mmio, bool pci_force_probing)
+{
+    if (disable_pci_mmio) {
+        if (test_pci_io(pci_force_probing)) {
+            initialize_pci_io_access();
+        } else {
+            kprintf("No PCI Bus Access Method Detected, Halt!\n");
+            ASSERT_NOT_REACHED(); // NO PCI Access ?!
+        }
+        return;
+    }
+    if (test_acpi()) {
+        if (test_pci_mmio()) {
+            initialize_pci_mmio_access_after_test();
+        } else {
+            if (test_pci_io(pci_force_probing)) {
+                initialize_pci_io_access();
+            } else {
+                kprintf("No PCI Bus Access Method Detected, Halt!\n");
+                ASSERT_NOT_REACHED(); // NO PCI Access ?!
+            }
+        }
+    } else {
+        if (test_pci_io(pci_force_probing)) {
+            initialize_pci_io_access();
+        } else {
+            kprintf("No PCI Bus Access Method Detected, Halt!\n");
+            ASSERT_NOT_REACHED(); // NO PCI Access ?!
+        }
+    }
+}
+PCI::Initializer::Initializer()
+{
+}
+bool PCI::Initializer::test_acpi()
+{
+    if ((KParams::the().has("noacpi")) || !ACPIParser::the().is_operable())
+        return false;
+    else
+        return true;
+}
+
+bool PCI::Initializer::test_pci_io(bool pci_force_probing)
+{
+    kprintf("Testing PCI via SMBIOS...\n");
+
+    if (!pci_force_probing) {
+        if (DMIDecoder::the().is_reliable()) {
+            if ((DMIDecoder::the().get_bios_characteristics() & (1 << 3)) != 0) {
+                kprintf("DMIDecoder: Warning, BIOS characteristics are not supported, skipping\n");
+            } else if ((DMIDecoder::the().get_bios_characteristics() & (u32)SMBIOS::BIOSCharacteristics::PCI_support) != 0) {
+                kprintf("PCI *should* be supported according to SMBIOS...\n");
+                return true;
+            } else {
+                kprintf("SMBIOS does not list PCI as supported, Falling back to manual probing!\n");
+            }
+        } else {
+            kprintf("DMI is classified as unreliable, ignore it!\n");
+        }
+    } else {
+        kprintf("Requested to force PCI probing...\n");
+    }
+
+    kprintf("Testing PCI via manual probing... ");
+
+    u32 tmp = 0x80000000;
+    IO::out32(PCI_ADDRESS_PORT, tmp);
+    tmp = IO::in32(PCI_ADDRESS_PORT);
+    if (tmp == 0x80000000) {
+        kprintf("PCI IO Supported!\n");
+        return true;
+    }
+
+    kprintf("PCI IO Not Supported!\n");
+    return false;
+}
+
+bool PCI::Initializer::test_pci_mmio()
+{
+    if (ACPIParser::the().find_table("MCFG") != nullptr)
+        return true;
+    else
+        return false;
+}
+
+void PCI::Initializer::initialize_pci_mmio_access_after_test()
+{
+    initialize_pci_mmio_access(*(ACPI_RAW::MCFG*)(ACPIParser::the().find_table("MCFG")));
+}
+
+void PCI::Initializer::dismiss()
+{
+    if (s_pci_initializer == nullptr)
+        return;
+    kprintf("PCI Subsystem Initializer dismissed.\n");
+    s_pci_initializer->~Initializer();
+}
+
+PCI::Initializer::~Initializer()
+{
+}
\ No newline at end of file
diff --git a/Kernel/PCI/Initializer.h b/Kernel/PCI/Initializer.h
new file mode 100644
index 0000000000..875ba2afa6
--- /dev/null
+++ b/Kernel/PCI/Initializer.h
@@ -0,0 +1,22 @@
+#pragma once
+
+#include <AK/Types.h>
+#include <Kernel/ACPI/Definitions.h>
+#include <Kernel/PCI/Definitions.h>
+
+class PCI::Initializer {
+public:
+    static PCI::Initializer& the();
+    void initialize_pci_mmio_access(ACPI_RAW::MCFG& mcfg);
+    void initialize_pci_io_access();
+    void test_and_initialize(bool disable_pci_mmio, bool pci_force_probing);
+    static void dismiss();
+
+private:
+    ~Initializer();
+    Initializer();
+    bool test_acpi();
+    bool test_pci_io(bool pci_force_probing);
+    bool test_pci_mmio();
+    void initialize_pci_mmio_access_after_test();
+};
\ No newline at end of file
diff --git a/Kernel/PCI/MMIOAccess.cpp b/Kernel/PCI/MMIOAccess.cpp
new file mode 100644
index 0000000000..3b148ae979
--- /dev/null
+++ b/Kernel/PCI/MMIOAccess.cpp
@@ -0,0 +1,215 @@
+#include <AK/Optional.h>
+#include <Kernel/IO.h>
+#include <Kernel/PCI/MMIOAccess.h>
+#include <Kernel/VM/MemoryManager.h>
+
+#define PCI_MMIO_CONFIG_SPACE_SIZE 4096
+
+uint32_t PCI::MMIOAccess::get_segments_count()
+{
+    return m_segments.size();
+}
+uint8_t PCI::MMIOAccess::get_segment_start_bus(u32 seg)
+{
+    ASSERT(m_segments.contains(seg));
+    return m_segments.get(seg).value()->get_start_bus();
+}
+uint8_t PCI::MMIOAccess::get_segment_end_bus(u32 seg)
+{
+    ASSERT(m_segments.contains(seg));
+    return m_segments.get(seg).value()->get_end_bus();
+}
+
+void PCI::MMIOAccess::initialize(ACPI_RAW::MCFG& mcfg)
+{
+    if (!PCI::Access::is_initialized())
+        new PCI::MMIOAccess(mcfg);
+}
+
+PCI::MMIOAccess::MMIOAccess(ACPI_RAW::MCFG& raw_mcfg)
+    : m_mcfg(raw_mcfg)
+    , m_segments(*new HashMap<u16, MMIOSegment*>())
+{
+    kprintf("PCI: Using MMIO Mechanism for PCI Configuartion Space Access\n");
+    m_mmio_segment = MM.allocate_kernel_region(PAGE_ROUND_UP(PCI_MMIO_CONFIG_SPACE_SIZE), "PCI MMIO", Region::Access::Read | Region::Access::Write);
+
+    OwnPtr<Region> checkup_region = MM.allocate_kernel_region((PAGE_SIZE * 2), "PCI MCFG Checkup", Region::Access::Read | Region::Access::Write);
+#ifdef PCI_DEBUG
+    dbgprintf("PCI: Checking MCFG Table length to choose the correct mapping size\n");
+#endif
+    mmap_region(*checkup_region, PhysicalAddress((u32)&raw_mcfg & 0xfffff000));
+    ACPI_RAW::SDTHeader* sdt = (ACPI_RAW::SDTHeader*)(checkup_region->vaddr().get() + ((u32)&raw_mcfg & 0xfff));
+    u32 length = sdt->length;
+    u8 revision = sdt->revision;
+
+    kprintf("PCI: MCFG, length - %u, revision %d\n", length, revision);
+    checkup_region->unmap();
+
+    auto mcfg_region = MM.allocate_kernel_region(PAGE_ROUND_UP(length) + PAGE_SIZE, "PCI Parsing MCFG", Region::Access::Read | Region::Access::Write);
+    mmap_region(*mcfg_region, PhysicalAddress((u32)&raw_mcfg & 0xfffff000));
+
+    ACPI_RAW::MCFG& mcfg = *((ACPI_RAW::MCFG*)(mcfg_region->vaddr().get() + ((u32)&raw_mcfg & 0xfff)));
+#ifdef PCI_DEBUG
+    dbgprintf("PCI: Checking MCFG @ V 0x%x, P 0x%x\n", &mcfg, &raw_mcfg);
+#endif
+
+    for (u32 index = 0; index < ((mcfg.header.length - sizeof(ACPI_RAW::MCFG)) / sizeof(ACPI_RAW::PCI_MMIO_Descriptor)); index++) {
+        u8 start_bus = mcfg.descriptors[index].start_pci_bus;
+        u8 end_bus = mcfg.descriptors[index].end_pci_bus;
+        u32 lower_addr = mcfg.descriptors[index].base_addr;
+
+        m_segments.set(index, new PCI::MMIOSegment(PhysicalAddress(lower_addr), start_bus, end_bus));
+        kprintf("PCI: New PCI segment @ P 0x%x, PCI buses (%d-%d)\n", lower_addr, start_bus, end_bus);
+    }
+    mcfg_region->unmap();
+    kprintf("PCI: MMIO segments - %d\n", m_segments.size());
+    map_device(Address(0, 0, 0, 0));
+}
+
+void PCI::MMIOAccess::map_device(Address address)
+{
+    // FIXME: Map and put some lock!
+#ifdef PCI_DEBUG
+    dbgprintf("PCI: Mapping Device @ pci (%d:%d:%d:%d)\n", address.seg(), address.bus(), address.slot(), address.function());
+#endif
+    ASSERT(m_segments.contains(address.seg()));
+    auto segment = m_segments.get(address.seg());
+    PhysicalAddress segment_lower_addr = segment.value()->get_paddr();
+    PhysicalAddress device_physical_mmio_space = segment_lower_addr.offset(
+        PCI_MMIO_CONFIG_SPACE_SIZE * address.function() + (PCI_MMIO_CONFIG_SPACE_SIZE * PCI_MAX_FUNCTIONS_PER_DEVICE) * address.slot() + (PCI_MMIO_CONFIG_SPACE_SIZE * PCI_MAX_FUNCTIONS_PER_DEVICE * PCI_MAX_DEVICES_PER_BUS) * (address.bus() - segment.value()->get_start_bus()));
+#ifdef PCI_DEBUG
+    dbgprintf("PCI: Mapping (%d:%d:%d:%d), V 0x%x, P 0x%x\n", address.seg(), address.bus(), address.slot(), address.function(), m_mmio_segment->vaddr().get(), device_physical_mmio_space.get());
+#endif
+    MM.map_for_kernel(m_mmio_segment->vaddr(), device_physical_mmio_space, false);
+}
+
+u8 PCI::MMIOAccess::read8_field(Address address, u32 field)
+{
+    ASSERT(field <= 0xfff);
+#ifdef PCI_DEBUG
+    dbgprintf("PCI: Reading field %u, Address(%u:%u:%u:%u)\n", field, address.seg(), address.bus(), address.slot(), address.function());
+#endif
+    map_device(address);
+    return *((u8*)(m_mmio_segment->vaddr().get() + (field & 0xfff)));
+}
+
+u16 PCI::MMIOAccess::read16_field(Address address, u32 field)
+{
+    ASSERT(field < 0xfff);
+#ifdef PCI_DEBUG
+    dbgprintf("PCI: Reading field %u, Address(%u:%u:%u:%u)\n", field, address.seg(), address.bus(), address.slot(), address.function());
+#endif
+    map_device(address);
+    return *((u16*)(m_mmio_segment->vaddr().get() + (field & 0xfff)));
+}
+
+u32 PCI::MMIOAccess::read32_field(Address address, u32 field)
+{
+    ASSERT(field <= 0xffc);
+#ifdef PCI_DEBUG
+    dbgprintf("PCI: Reading field %u, Address(%u:%u:%u:%u)\n", field, address.seg(), address.bus(), address.slot(), address.function());
+#endif
+    map_device(address);
+    return *((u32*)(m_mmio_segment->vaddr().get() + (field & 0xfff)));
+}
+
+void PCI::MMIOAccess::write8_field(Address address, u32 field, u8 value)
+{
+    ASSERT(field <= 0xfff);
+#ifdef PCI_DEBUG
+    dbgprintf("PCI: Write to field %u, Address(%u:%u:%u:%u), value 0x%x\n", field, address.seg(), address.bus(), address.slot(), address.function(), value);
+#endif
+    map_device(address);
+    *((u8*)(m_mmio_segment->vaddr().get() + (field & 0xfff))) = value;
+}
+void PCI::MMIOAccess::write16_field(Address address, u32 field, u16 value)
+{
+    ASSERT(field < 0xfff);
+#ifdef PCI_DEBUG
+    dbgprintf("PCI: Write to field %u, Address(%u:%u:%u:%u), value 0x%x\n", field, address.seg(), address.bus(), address.slot(), address.function(), value);
+#endif
+    map_device(address);
+    *((u16*)(m_mmio_segment->vaddr().get() + (field & 0xfff))) = value;
+}
+void PCI::MMIOAccess::write32_field(Address address, u32 field, u32 value)
+{
+    ASSERT(field <= 0xffc);
+#ifdef PCI_DEBUG
+    dbgprintf("PCI: Write to field %u, Address(%u:%u:%u:%u), value 0x%x\n", field, address.seg(), address.bus(), address.slot(), address.function(), value);
+#endif
+    map_device(address);
+    *((u32*)(m_mmio_segment->vaddr().get() + (field & 0xfff))) = value;
+}
+
+void PCI::MMIOAccess::enumerate_all(Function<void(Address, ID)>& callback)
+{
+    for (u16 seg = 0; seg < m_segments.size(); seg++) {
+#ifdef PCI_DEBUG
+        dbgprintf("PCI: Enumerating Memory mapped IO segment %u\n", seg);
+#endif
+        // Single PCI host controller.
+        if ((read8_field(Address(seg), PCI_HEADER_TYPE) & 0x80) == 0) {
+            enumerate_bus(-1, 0, callback);
+            return;
+        }
+
+        // Multiple PCI host controllers.
+        for (u8 function = 0; function < 8; ++function) {
+            if (read16_field(Address(seg, 0, 0, function), PCI_VENDOR_ID) == PCI_NONE)
+                break;
+            enumerate_bus(-1, function, callback);
+        }
+    }
+}
+
+void PCI::MMIOAccess::mmap(VirtualAddress vaddr, PhysicalAddress paddr, u32 length)
+{
+    unsigned i = 0;
+    while (length >= PAGE_SIZE) {
+        MM.map_for_kernel(VirtualAddress(vaddr.offset(i * PAGE_SIZE).get()), PhysicalAddress(paddr.offset(i * PAGE_SIZE).get()));
+#ifdef ACPI_DEBUG
+        dbgprintf("PCI: map - V 0x%x -> P 0x%x\n", vaddr.offset(i * PAGE_SIZE).get(), paddr.offset(i * PAGE_SIZE).get());
+#endif
+        length -= PAGE_SIZE;
+        i++;
+    }
+    if (length > 0) {
+        MM.map_for_kernel(vaddr.offset(i * PAGE_SIZE), paddr.offset(i * PAGE_SIZE), true);
+    }
+#ifdef ACPI_DEBUG
+    dbgprintf("PCI: Finished mapping\n");
+#endif
+}
+
+void PCI::MMIOAccess::mmap_region(Region& region, PhysicalAddress paddr)
+{
+#ifdef PCI_DEBUG
+    dbgprintf("PCI: Mapping region, size - %u\n", region.size());
+#endif
+    mmap(region.vaddr(), paddr, region.size());
+}
+
+PCI::MMIOSegment::MMIOSegment(PhysicalAddress segment_base_addr, u8 start_bus, u8 end_bus)
+    : m_base_addr(segment_base_addr)
+    , m_start_bus(start_bus)
+    , m_end_bus(end_bus)
+{
+}
+u8 PCI::MMIOSegment::get_start_bus()
+{
+    return m_start_bus;
+}
+u8 PCI::MMIOSegment::get_end_bus()
+{
+    return m_end_bus;
+}
+
+size_t PCI::MMIOSegment::get_size()
+{
+    return (PCI_MMIO_CONFIG_SPACE_SIZE * PCI_MAX_FUNCTIONS_PER_DEVICE * PCI_MAX_DEVICES_PER_BUS * (get_end_bus() - get_start_bus()));
+}
+
+PhysicalAddress PCI::MMIOSegment::get_paddr()
+{
+    return m_base_addr;
+}
diff --git a/Kernel/PCI/MMIOAccess.h b/Kernel/PCI/MMIOAccess.h
new file mode 100644
index 0000000000..de48563383
--- /dev/null
+++ b/Kernel/PCI/MMIOAccess.h
@@ -0,0 +1,53 @@
+#pragma once
+#include <AK/HashMap.h>
+#include <AK/OwnPtr.h>
+#include <AK/Types.h>
+#include <Kernel/ACPI/Definitions.h>
+#include <Kernel/PCI/Access.h>
+#include <Kernel/VM/PhysicalRegion.h>
+#include <Kernel/VM/Region.h>
+
+class PCI::MMIOAccess final : public PCI::Access {
+public:
+    static void initialize(ACPI_RAW::MCFG&);
+    virtual void enumerate_all(Function<void(Address, ID)>&) override final;
+
+    virtual String get_access_type() override final { return "MMIO-Access"; };
+
+protected:
+    MMIOAccess(ACPI_RAW::MCFG&);
+
+private:
+    virtual u8 read8_field(Address address, u32) override final;
+    virtual u16 read16_field(Address address, u32) override final;
+    virtual u32 read32_field(Address address, u32) override final;
+    virtual void write8_field(Address address, u32, u8) override final;
+    virtual void write16_field(Address address, u32, u16) override final;
+    virtual void write32_field(Address address, u32, u32) override final;
+
+    void map_device(Address address);
+    void mmap(VirtualAddress preferred_vaddr, PhysicalAddress paddr, u32);
+    void mmap_region(Region& region, PhysicalAddress paddr);
+
+    virtual u32 get_segments_count();
+    virtual u8 get_segment_start_bus(u32);
+    virtual u8 get_segment_end_bus(u32);
+
+    ACPI_RAW::MCFG& m_mcfg;
+    HashMap<u16, MMIOSegment*>& m_segments;
+    OwnPtr<Region> m_mmio_segment;
+};
+
+class PCI::MMIOSegment {
+public:
+    MMIOSegment(PhysicalAddress, u8, u8);
+    u8 get_start_bus();
+    u8 get_end_bus();
+    size_t get_size();
+    PhysicalAddress get_paddr();
+
+private:
+    PhysicalAddress m_base_addr;
+    u8 m_start_bus;
+    u8 m_end_bus;
+};
\ No newline at end of file
diff --git a/Kernel/init.cpp b/Kernel/init.cpp
index 01ce09a943..24f1fd0ea8 100644
--- a/Kernel/init.cpp
+++ b/Kernel/init.cpp
@@ -5,6 +5,9 @@
 #include "Scheduler.h"
 #include "kstdio.h"
 #include <AK/Types.h>
+#include <Kernel/ACPI/ACPIDynamicParser.h>
+#include <Kernel/ACPI/ACPIStaticParser.h>
+#include <Kernel/ACPI/DMIDecoder.h>
 #include <Kernel/Arch/i386/APIC.h>
 #include <Kernel/Arch/i386/CPU.h>
 #include <Kernel/Arch/i386/PIC.h>
@@ -39,7 +42,8 @@
 #include <Kernel/Net/LoopbackAdapter.h>
 #include <Kernel/Net/NetworkTask.h>
 #include <Kernel/Net/RTL8139NetworkAdapter.h>
-#include <Kernel/PCI.h>
+#include <Kernel/PCI/Access.h>
+#include <Kernel/PCI/Initializer.h>
 #include <Kernel/TTY/PTYMultiplexer.h>
 #include <Kernel/TTY/VirtualConsole.h>
 #include <Kernel/VM/MemoryManager.h>
@@ -245,6 +249,35 @@ extern "C" [[noreturn]] void init(u32 physical_address_for_kernel_page_tables)
     new KParams(String(reinterpret_cast<const char*>(multiboot_info_ptr->cmdline)));
 
     bool text_debug = KParams::the().has("text_debug");
+    bool complete_acpi_disable = KParams::the().has("noacpi");
+    bool dynamic_acpi_disable = KParams::the().has("noacpi_aml");
+    bool pci_mmio_disable = KParams::the().has("nopci_mmio");
+    bool pci_force_probing = KParams::the().has("pci_nodmi");
+    bool dmi_unreliable = KParams::the().has("dmi_unreliable");
+
+    MemoryManager::initialize(physical_address_for_kernel_page_tables);
+
+    if (dmi_unreliable) {
+        DMIDecoder::initialize_untrusted();
+    } else {
+        DMIDecoder::initialize();
+    }
+
+    if (complete_acpi_disable) {
+        ACPIParser::initialize_limited();
+    } else {
+        if (!dynamic_acpi_disable) {
+            ACPIDynamicParser::initialize_without_rsdp();
+        } else {
+            ACPIStaticParser::initialize_without_rsdp();
+        }
+    }
+
+    // Sample test to see if the ACPI parser is working...
+    kprintf("ACPI: HPET table @ P 0x%x\n", ACPIParser::the().find_table("HPET"));
+
+    PCI::Initializer::the().test_and_initialize(pci_mmio_disable, pci_force_probing);
+    PCI::Initializer::the().dismiss();
 
     vfs = new VFS;
     dev_debuglog = new DebugLogDevice;
@@ -298,15 +331,14 @@ extern "C" [[noreturn]] void init(u32 physical_address_for_kernel_page_tables)
     tty1 = new VirtualConsole(1);
     VirtualConsole::switch_to(0);
 
-    MemoryManager::initialize(physical_address_for_kernel_page_tables);
-
     if (APIC::init())
         APIC::enable(0);
 
     PIT::initialize();
 
     PCI::enumerate_all([](const PCI::Address& address, PCI::ID id) {
-        kprintf("PCI device: bus=%d slot=%d function=%d id=%w:%w\n",
+        kprintf("PCI: device @ %w:%b:%b.%d [%w:%w]\n",
+            address.seg(),
             address.bus(),
             address.slot(),
             address.function(),