Kernel/PCI: Split Access::rescan_hardware method

To ensure clarity, this method is essentially splitted to two methods to
be called according to the access type being determined beforehand.

Kernel/Bus/PCI/Access.cpp

@@ -44,7 +44,7 @@ UNMAP_AFTER_INIT bool Access::initialize_for_memory_access(PhysicalAddress mcfg_
  auto* access = new Access(Access::AccessType::Memory);
  if (!access->search_pci_domains_from_acpi_mcfg_table(mcfg_table))
  return false;
- access->rescan_hardware();
+ access->rescan_hardware_with_memory_addressing();
  dbgln_if(PCI_DEBUG, "PCI: MMIO access initialised.");
  return true;
 }
@@ -86,7 +86,7 @@ UNMAP_AFTER_INIT bool Access::initialize_for_io_access()
  return false;
  }
  auto* access = new Access(Access::AccessType::IO);
- access->rescan_hardware();
+ access->rescan_hardware_with_io_addressing();
  dbgln_if(PCI_DEBUG, "PCI: IO access initialised.");
  return true;
 }
@@ -305,37 +305,11 @@ u32 Access::read32_field(Address address, u32 field)
  VERIFY_NOT_REACHED();
 }
 
-UNMAP_AFTER_INIT void Access::rescan_hardware()
+UNMAP_AFTER_INIT void Access::rescan_hardware_with_memory_addressing()
 {
  MutexLocker locker(m_scan_lock);
  VERIFY(m_device_identifiers.is_empty());
- if (m_access_type == AccessType::IO) {
- dbgln_if(PCI_DEBUG, "PCI: IO enumerating hardware");
-
- // First scan bus 0. Find any device on that bus, and if it's a PCI-to-PCI
- // bridge, recursively scan it too.
- m_enumerated_buses.set(0, true);
- enumerate_bus(-1, 0, true);
-
- // Handle Multiple PCI host bridges on slot 0, device 0.
- // If we happen to miss some PCI buses because they are not reachable through
- // recursive PCI-to-PCI bridges starting from bus 0, we might find them here.
- if ((read8_field(Address(), PCI::RegisterOffset::HEADER_TYPE) & 0x80) != 0) {
- for (int bus = 1; bus < 256; ++bus) {
- if (read16_field(Address(0, 0, 0, bus), PCI::RegisterOffset::VENDOR_ID) == PCI::none_value)
- continue;
- if (read16_field(Address(0, 0, 0, bus), PCI::RegisterOffset::CLASS) != 0x6)
- continue;
- if (m_enumerated_buses.get(bus))
- continue;
- enumerate_bus(-1, bus, false);
- m_enumerated_buses.set(bus, true);
- }
- }
- return;
- }
  VERIFY(m_access_type == AccessType::Memory);
-
  for (u32 domain = 0; domain < m_domains.size(); domain++) {
  dbgln_if(PCI_DEBUG, "PCI: Scan memory mapped domain {}", domain);
  // Single PCI host controller.
@@ -353,6 +327,49 @@ UNMAP_AFTER_INIT void Access::rescan_hardware()
  }
 }
 
+UNMAP_AFTER_INIT void Access::rescan_hardware_with_io_addressing()
+{
+ MutexLocker locker(m_scan_lock);
+ VERIFY(m_device_identifiers.is_empty());
+ VERIFY(m_access_type == AccessType::IO);
+ dbgln_if(PCI_DEBUG, "PCI: IO enumerating hardware");
+
+ // First scan bus 0. Find any device on that bus, and if it's a PCI-to-PCI
+ // bridge, recursively scan it too.
+ m_enumerated_buses.set(0, true);
+ enumerate_bus(-1, 0, true);
+
+ // Handle Multiple PCI host bridges on slot 0, device 0.
+ // If we happen to miss some PCI buses because they are not reachable through
+ // recursive PCI-to-PCI bridges starting from bus 0, we might find them here.
+ if ((read8_field(Address(), PCI::RegisterOffset::HEADER_TYPE) & 0x80) != 0) {
+ for (int bus = 1; bus < 256; ++bus) {
+ if (read16_field(Address(0, 0, 0, bus), PCI::RegisterOffset::VENDOR_ID) == PCI::none_value)
+ continue;
+ if (read16_field(Address(0, 0, 0, bus), PCI::RegisterOffset::CLASS) != 0x6)
+ continue;
+ if (m_enumerated_buses.get(bus))
+ continue;
+ enumerate_bus(-1, bus, false);
+ m_enumerated_buses.set(bus, true);
+ }
+ }
+}
+
+UNMAP_AFTER_INIT void Access::rescan_hardware()
+{
+ switch (m_access_type) {
+ case AccessType::IO:
+ rescan_hardware_with_io_addressing();
+ break;
+ case AccessType::Memory:
+ rescan_hardware_with_memory_addressing();
+ break;
+ default:
+ VERIFY_NOT_REACHED();
+ }
+}
+
 UNMAP_AFTER_INIT Optional<u8> Access::get_capabilities_pointer(Address address)
 {
  dbgln_if(PCI_DEBUG, "PCI: Getting capabilities pointer for {}", address);

Kernel/Bus/PCI/Access.h

@@ -27,6 +27,8 @@ class Access {
 
  void fast_enumerate(Function<void(DeviceIdentifier const&)>&) const;
  void rescan_hardware();
+ void rescan_hardware_with_memory_addressing();
+ void rescan_hardware_with_io_addressing();
 
  static Access& the();
  static bool is_initialized();