Kernel: Fix up various PCI-related function signatures

- Make things const when they don't need to be non-const.
- Don't return AK::String when it's always a string literal anyway.
- Remove excessive get_ prefixes per coding style.

Kernel/PCI/Access.h

@@ -41,10 +41,10 @@ public:
 
     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;
+    virtual uint32_t segment_count() const = 0;
+    virtual uint8_t segment_start_bus(u32 segment) const = 0;
+    virtual uint8_t segment_end_bus(u32 segment) const = 0;
+    virtual const char* access_type() const = 0;
 
     virtual void write8_field(Address address, u32 field, u8 value) = 0;
     virtual void write16_field(Address address, u32 field, u16 value) = 0;

Kernel/PCI/IOAccess.h

@@ -28,29 +28,29 @@
 #include <Kernel/PCI/Access.h>
 
 namespace Kernel {
+namespace PCI {
 
-class PCI::IOAccess final : public PCI::Access {
+class 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"; };
-    virtual uint32_t get_segments_count() { return 1; };
-
-    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;
 
 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 enumerate_all(Function<void(Address, ID)>&) override;
+    virtual const char* access_type() const override { return "IO-Access"; };
+    virtual uint32_t segment_count() const override { return 1; };
+    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 u8 read8_field(Address address, u32) override;
+    virtual u16 read16_field(Address address, u32) override;
+    virtual u32 read32_field(Address address, u32) override;
 
-    virtual uint8_t get_segment_start_bus(u32) { return 0x0; };
-    virtual uint8_t get_segment_end_bus(u32) { return 0xFF; };
+    virtual uint8_t segment_start_bus(u32) const override { return 0x0; }
+    virtual uint8_t segment_end_bus(u32) const override { return 0xFF; }
 };
 
 }
+}

Kernel/PCI/MMIOAccess.cpp

@@ -33,16 +33,18 @@ namespace Kernel {
 
 #define PCI_MMIO_CONFIG_SPACE_SIZE 4096
 
-uint32_t PCI::MMIOAccess::get_segments_count()
+uint32_t PCI::MMIOAccess::segment_count() const
 {
     return m_segments.size();
 }
-uint8_t PCI::MMIOAccess::get_segment_start_bus(u32 seg)
+
+uint8_t PCI::MMIOAccess::segment_start_bus(u32 seg) const
 {
     ASSERT(m_segments.contains(seg));
     return m_segments.get(seg).value()->get_start_bus();
 }
-uint8_t PCI::MMIOAccess::get_segment_end_bus(u32 seg)
+
+uint8_t PCI::MMIOAccess::segment_end_bus(u32 seg) const
 {
     ASSERT(m_segments.contains(seg));
     return m_segments.get(seg).value()->get_end_bus();
@@ -213,10 +215,12 @@ PCI::MMIOSegment::MMIOSegment(PhysicalAddress segment_base_addr, u8 start_bus, u
     , 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;

Kernel/PCI/MMIOAccess.h

@@ -42,8 +42,8 @@ public:
     static void initialize(PhysicalAddress mcfg);
     virtual void enumerate_all(Function<void(Address, ID)>&) override final;
 
-    virtual String get_access_type() override final { return "MMIO-Access"; };
-    virtual u32 get_segments_count();
+    virtual const char* access_type() const override { return "MMIO-Access"; };
+    virtual u32 segment_count() const override;
 
     virtual void write8_field(Address address, u32, u8) override final;
     virtual void write16_field(Address address, u32, u16) override final;
@@ -58,8 +58,8 @@ private:
     virtual u32 read32_field(Address address, u32) override final;
 
     void map_device(Address address);
-    virtual u8 get_segment_start_bus(u32);
-    virtual u8 get_segment_end_bus(u32);
+    virtual u8 segment_start_bus(u32) const override;
+    virtual u8 segment_end_bus(u32) const override;
 
     PhysicalAddress m_mcfg;
     HashMap<u16, MMIOSegment*>& m_segments;