Implement RTC flag, which is counter-intuitively disc drive related

Source/Core/Core/Boot/Boot_BS2Emu.cpp

@@ -19,6 +19,7 @@
 #include "Core/ConfigManager.h"
 #include "Core/Core.h"
 #include "Core/HLE/HLE.h"
+#include "Core/HW/DVD/DVDInterface.h"
 #include "Core/HW/EXI/EXI_DeviceIPL.h"
 #include "Core/HW/Memmap.h"
 #include "Core/IOS/ES/ES.h"
@@ -390,6 +391,9 @@ bool CBoot::EmulatedBS2_Wii(const DiscIO::VolumeDisc& volume)
     state->discstate = 0x01;
   });
 
+  // The system menu clears the RTC flags
+  ExpansionInterface::g_rtc_flags.m_hex = 0;
+
   // While reading a disc, the system menu reads the first partition table
   // (0x20 bytes from 0x00040020) and stores a pointer to the data partition entry.
   // When launching the disc game, it copies the partition type and offset to 0x3194

Source/Core/Core/HW/DVD/DVDInterface.cpp

@@ -25,6 +25,7 @@
 #include "Core/HW/AudioInterface.h"
 #include "Core/HW/DVD/DVDMath.h"
 #include "Core/HW/DVD/DVDThread.h"
+#include "Core/HW/EXI/EXI_DeviceIPL.h"
 #include "Core/HW/MMIO.h"
 #include "Core/HW/Memmap.h"
 #include "Core/HW/ProcessorInterface.h"
@@ -473,7 +474,9 @@ void Shutdown()
 void SetDisc(std::unique_ptr<DiscIO::VolumeDisc> disc,
              std::optional<std::vector<std::string>> auto_disc_change_paths = {})
 {
-  if (disc)
+  bool had_disc = IsDiscInside();
+  bool has_disc = static_cast<bool>(disc);
+  if (has_disc)
     s_current_partition = disc->GetGamePartition();
 
   if (auto_disc_change_paths)
@@ -485,6 +488,10 @@ void SetDisc(std::unique_ptr<DiscIO::VolumeDisc> disc,
     s_auto_disc_change_index = 0;
   }
 
+  // Assume that inserting a disc requires having an empty disc before
+  if (had_disc != has_disc)
+    ExpansionInterface::g_rtc_flags[ExpansionInterface::RTCFlag::DiscChanged] = true;
+
   DVDThread::SetDisc(std::move(disc));
   SetLidOpen();
 }
@@ -517,9 +524,11 @@ static void InsertDiscCallback(u64 userdata, s64 cyclesLate)
 }
 
 // Must only be called on the CPU thread
-void EjectDisc()
+void EjectDisc(EjectCause cause)
 {
   CoreTiming::ScheduleEvent(0, s_eject_disc);
+  if (cause == EjectCause::User)
+    ExpansionInterface::g_rtc_flags[ExpansionInterface::RTCFlag::EjectButton] = true;
 }
 
 // Must only be called on the CPU thread
@@ -545,7 +554,7 @@ void ChangeDisc(const std::string& new_path)
     return;
   }
 
-  EjectDisc();
+  EjectDisc(EjectCause::User);
 
   s_disc_path_to_insert = new_path;
   CoreTiming::ScheduleEvent(SystemTimers::GetTicksPerSecond(), s_insert_disc);
@@ -1072,7 +1081,7 @@ void ExecuteCommand(u32 command_0, u32 command_1, u32 command_2, u32 output_addr
     }
     else if (force_eject)
     {
-      EjectDiscCallback(0, 0);
+      EjectDisc(EjectCause::Software);
     }
     break;
   }

Source/Core/Core/HW/DVD/DVDInterface.h

@@ -74,6 +74,12 @@ enum class ReplyType : u32
   DTK
 };
 
+enum class EjectCause
+{
+  User,
+  Software,
+};
+
 void Init();
 void Reset();
 void Shutdown();
@@ -84,7 +90,7 @@ void RegisterMMIO(MMIO::Mapping* mmio, u32 base);
 void SetDisc(std::unique_ptr<DiscIO::VolumeDisc> disc,
              std::optional<std::vector<std::string>> auto_disc_change_paths);
 bool IsDiscInside();
-void EjectDisc();                                        // Must only be called on the CPU thread
+void EjectDisc(EjectCause cause);                        // Must only be called on the CPU thread
 void ChangeDisc(const std::vector<std::string>& paths);  // Must only be called on the CPU thread
 void ChangeDisc(const std::string& new_path);            // Must only be called on the CPU thread
 bool AutoChangeDisc();                                   // Must only be called on the CPU thread

Source/Core/Core/HW/EXI/EXI_DeviceIPL.cpp

@@ -3,6 +3,7 @@
 // Refer to the license.txt file included.
 
 #include "Core/HW/EXI/EXI_DeviceIPL.h"
+#include "Core/HW/DVD/DVDInterface.h"
 
 #include <cstring>
 #include <string>
@@ -43,6 +44,8 @@ static const char iplverPAL[0x100] = "(C) 1999-2001 Nintendo.  All rights reserv
 static const char iplverNTSC[0x100] = "(C) 1999-2001 Nintendo.  All rights reserved."
                                       "(C) 1999 ArtX Inc.  All rights reserved.";
 
+Common::Flags<RTCFlag> g_rtc_flags;
+
 // bootrom descrambler reversed by segher
 // Copyright 2008 Segher Boessenkool <segher@kernel.crashing.org>
 void CEXIIPL::Descrambler(u8* data, u32 size)
@@ -149,6 +152,7 @@ CEXIIPL::~CEXIIPL()
 void CEXIIPL::DoState(PointerWrap& p)
 {
   p.Do(g_SRAM.rtc);
+  p.Do(g_rtc_flags);
   p.Do(m_command);
   p.Do(m_command_bytes_received);
   p.Do(m_cursor);
@@ -361,10 +365,12 @@ void CEXIIPL::TransferByte(u8& data)
         break;
       }
     }
-    else if (IN_RANGE(WII_RTC))
+    else if (IN_RANGE(WII_RTC) && DEV_ADDR(WII_RTC) == 0x20)
     {
-      // Wii only RTC flags... afaik only the Wii Menu initializes it
-      // Seems to be 4bytes at dev_addr 0x20
+      if (m_command.is_write())
+        g_rtc_flags.m_hex = data;
+      else
+        data = g_rtc_flags.m_hex;
     }
     else if (IN_RANGE(EUART))
     {

Source/Core/Core/HW/EXI/EXI_DeviceIPL.h

@@ -7,6 +7,7 @@
 #include <array>
 #include <string>
 
+#include "Common/BitUtils.h"
 #include "Core/HW/EXI/EXI_Device.h"
 
 class PointerWrap;
@@ -78,4 +79,17 @@ private:
 
   static std::string FindIPLDump(const std::string& path_prefix);
 };
+
+// Used to indicate disc changes on the Wii, as insane as that sounds.
+// However, the name is definitely RTCFlag, as the code that gets it is __OSGetRTCFlags and
+// __OSClearRTCFlags in OSRtc.o (based on symbols from Kirby's Dream Collection)
+// This may simply be a single byte that gets repeated 4 times by some EXI quirk,
+// as reading it gives the value repeated 4 times but code only checks the first bit.
+enum class RTCFlag : u32
+{
+  EjectButton = 0x01010101,
+  DiscChanged = 0x02020202,
+};
+
+extern Common::Flags<RTCFlag> g_rtc_flags;
 }  // namespace ExpansionInterface

Source/Core/Core/HW/WII_IPC.cpp

@@ -194,7 +194,7 @@ void RegisterMMIO(MMIO::Mapping* mmio, u32 base)
                    if (g_gpio_out[GPIO::DO_EJECT])
                    {
                      INFO_LOG(WII_IPC, "Ejecting disc due to GPIO write");
-                     DVDInterface::EjectDisc();
+                     DVDInterface::EjectDisc(DVDInterface::EjectCause::Software);
                    }
                    // SENSOR_BAR is checked by WiimoteEmu::CameraLogic
                    // TODO: AVE, SLOT_LED

Source/Core/DolphinQt/MainWindow.cpp

@@ -686,7 +686,7 @@ void MainWindow::ChangeDisc()
 
 void MainWindow::EjectDisc()
 {
-  Core::RunAsCPUThread(DVDInterface::EjectDisc);
+  Core::RunAsCPUThread([] { DVDInterface::EjectDisc(DVDInterface::EjectCause::User); });
 }
 
 void MainWindow::Open()