Kernel/Net: Introduce a new mechanism to initialize a PCI device

Instead of using a clunky if-statement paradigm, we now have all drivers
being declaring two methods for their adapter class - create and probe.
These methods are linked in each PCINetworkDriverInitializer structure,
in a new s_initializers static list of them.
Then, when we probe for a PCI device, we use each probe method and if
there's a match, then the corresponding create method is called. After
the adapter instance is created, we call the virtual initialize method
on it, because many drivers actually require a sort of post-construction
initialization sequence to ensure the network adapter can properly
function.

As a result of this change, it's much more easy to add more drivers and
the initialization code is more readable and it's easier to understand
when and where things could fail in the whole initialization sequence.

2 files changed, 19 insertions, 9 deletions

diff --git a/Kernel/Net/NE2000/NetworkAdapter.cpp b/Kernel/Net/NE2000/NetworkAdapter.cpp
index 3df63f0be9..8d758926a5 100644
--- a/Kernel/Net/NE2000/NetworkAdapter.cpp
+++ b/Kernel/Net/NE2000/NetworkAdapter.cpp
@@ -138,7 +138,7 @@ struct [[gnu::packed]] received_packet_header {
     u16 length;
 };
 
-UNMAP_AFTER_INIT ErrorOr<LockRefPtr<NE2000NetworkAdapter>> NE2000NetworkAdapter::try_to_initialize(PCI::DeviceIdentifier const& pci_device_identifier)
+UNMAP_AFTER_INIT ErrorOr<bool> NE2000NetworkAdapter::probe(PCI::DeviceIdentifier const& pci_device_identifier)
 {
     constexpr auto ne2k_ids = Array {
         PCI::HardwareID { 0x10EC, 0x8029 }, // RealTek RTL-8029(AS)
@@ -155,19 +155,18 @@ UNMAP_AFTER_INIT ErrorOr<LockRefPtr<NE2000NetworkAdapter>> NE2000NetworkAdapter:
         PCI::HardwareID { 0x12c3, 0x5598 }, // Holtek HT80229
         PCI::HardwareID { 0x8c4a, 0x1980 }, // Winbond W89C940 (misprogrammed)
     };
-    if (!ne2k_ids.span().contains_slow(pci_device_identifier.hardware_id()))
-        return nullptr;
+    return ne2k_ids.span().contains_slow(pci_device_identifier.hardware_id());
+}
+
+UNMAP_AFTER_INIT ErrorOr<NonnullLockRefPtr<NetworkAdapter>> NE2000NetworkAdapter::create(PCI::DeviceIdentifier const& pci_device_identifier)
+{
     u8 irq = pci_device_identifier.interrupt_line().value();
     auto interface_name = TRY(NetworkingManagement::generate_interface_name_from_pci_address(pci_device_identifier));
     auto registers_io_window = TRY(IOWindow::create_for_pci_device_bar(pci_device_identifier, PCI::HeaderType0BaseRegister::BAR0));
     return TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) NE2000NetworkAdapter(pci_device_identifier.address(), irq, move(registers_io_window), move(interface_name))));
 }
 
-UNMAP_AFTER_INIT NE2000NetworkAdapter::NE2000NetworkAdapter(PCI::Address address, u8 irq, NonnullOwnPtr<IOWindow> registers_io_window, NonnullOwnPtr<KString> interface_name)
-    : NetworkAdapter(move(interface_name))
-    , PCI::Device(address)
-    , IRQHandler(irq)
-    , m_registers_io_window(move(registers_io_window))
+UNMAP_AFTER_INIT ErrorOr<void> NE2000NetworkAdapter::initialize(Badge<NetworkingManagement>)
 {
     dmesgln_pci(*this, "Found @ {}", pci_address());
 
@@ -181,6 +180,15 @@ UNMAP_AFTER_INIT NE2000NetworkAdapter::NE2000NetworkAdapter(PCI::Address address
     set_mac_address(m_mac_address);
     dmesgln_pci(*this, "MAC address: {}", m_mac_address.to_string());
     enable_irq();
+    return {};
+}
+
+UNMAP_AFTER_INIT NE2000NetworkAdapter::NE2000NetworkAdapter(PCI::Address address, u8 irq, NonnullOwnPtr<IOWindow> registers_io_window, NonnullOwnPtr<KString> interface_name)
+    : NetworkAdapter(move(interface_name))
+    , PCI::Device(address)
+    , IRQHandler(irq)
+    , m_registers_io_window(move(registers_io_window))
+{
 }
 
 UNMAP_AFTER_INIT NE2000NetworkAdapter::~NE2000NetworkAdapter() = default;
diff --git a/Kernel/Net/NE2000/NetworkAdapter.h b/Kernel/Net/NE2000/NetworkAdapter.h
index 33328fa0a2..6b73dcd939 100644
--- a/Kernel/Net/NE2000/NetworkAdapter.h
+++ b/Kernel/Net/NE2000/NetworkAdapter.h
@@ -20,7 +20,9 @@ class NE2000NetworkAdapter final : public NetworkAdapter
     , public PCI::Device
     , public IRQHandler {
 public:
-    static ErrorOr<LockRefPtr<NE2000NetworkAdapter>> try_to_initialize(PCI::DeviceIdentifier const&);
+    static ErrorOr<bool> probe(PCI::DeviceIdentifier const&);
+    static ErrorOr<NonnullLockRefPtr<NetworkAdapter>> create(PCI::DeviceIdentifier const&);
+    virtual ErrorOr<void> initialize(Badge<NetworkingManagement>) override;
 
     virtual ~NE2000NetworkAdapter() override;