HW/ProcessorInterface: Add support for all known registers

These changes originate from testing the behaviour of the PI registers
in Linux on my Wii.

I started by testing the masks, writing 0xFFFF_FFFF to the registers on
the Wii, and then got told about their value on a GameCube, and then
figured out most of the registers through a discussion with Extrems.

3 files changed, 62 insertions, 7 deletions

diff --git a/Source/Core/Core/HW/ProcessorInterface.cpp b/Source/Core/Core/HW/ProcessorInterface.cpp
index 7b999ac0de..10cca6c1c5 100644
--- a/Source/Core/Core/HW/ProcessorInterface.cpp
+++ b/Source/Core/Core/HW/ProcessorInterface.cpp
@@ -41,20 +41,27 @@ void ProcessorInterfaceManager::DoState(PointerWrap& p)
   p.Do(m_fifo_cpu_base);
   p.Do(m_fifo_cpu_end);
   p.Do(m_fifo_cpu_write_pointer);
+  p.Do(m_error_cause);
+  p.Do(m_error_address);
   p.Do(m_reset_code);
+  p.Do(m_unknown);
+  p.Do(m_flipper_bus_strength);
 }
 
 void ProcessorInterfaceManager::Init()
 {
   m_interrupt_mask = 0;
-  m_interrupt_cause = 0;
+  m_interrupt_cause = INT_CAUSE_RST_BUTTON | INT_CAUSE_VI;
 
   m_fifo_cpu_base = 0;
   m_fifo_cpu_end = 0;
   m_fifo_cpu_write_pointer = 0;
 
+  m_error_cause = 0;
+  m_error_address = 0;
   m_reset_code = 0;  // Cold reset
-  m_interrupt_cause = INT_CAUSE_RST_BUTTON | INT_CAUSE_VI;
+  m_unknown = 0x000001FF;
+  m_flipper_bus_strength = 0x02492492;
 
   auto& core_timing = m_system.GetCoreTiming();
   m_event_type_toggle_reset_button =
@@ -82,13 +89,25 @@ void ProcessorInterfaceManager::RegisterMMIO(MMIO::Mapping* mmio, u32 base)
                  }));
 
   mmio->Register(base | PI_FIFO_BASE, MMIO::DirectRead<u32>(&m_fifo_cpu_base),
-                 MMIO::DirectWrite<u32>(&m_fifo_cpu_base, 0xFFFFFFE0));
+                 MMIO::ComplexWrite<u32>([](Core::System& system, u32, u32 val) {
+                   u32 mask = CommandProcessor::GetPhysicalAddressMask(system.IsWii()) & 0xFFFFFFE0;
+                   auto& processor_interface = system.GetProcessorInterface();
+                   processor_interface.m_fifo_cpu_base = val & mask;
+                 }));
 
   mmio->Register(base | PI_FIFO_END, MMIO::DirectRead<u32>(&m_fifo_cpu_end),
-                 MMIO::DirectWrite<u32>(&m_fifo_cpu_end, 0xFFFFFFE0));
+                 MMIO::ComplexWrite<u32>([](Core::System& system, u32, u32 val) {
+                   u32 mask = CommandProcessor::GetPhysicalAddressMask(system.IsWii()) & 0xFFFFFFE0;
+                   auto& processor_interface = system.GetProcessorInterface();
+                   processor_interface.m_fifo_cpu_end = val & mask;
+                 }));
 
   mmio->Register(base | PI_FIFO_WPTR, MMIO::DirectRead<u32>(&m_fifo_cpu_write_pointer),
-                 MMIO::DirectWrite<u32>(&m_fifo_cpu_write_pointer, 0xFFFFFFE0));
+                 MMIO::ComplexWrite<u32>([](Core::System& system, u32, u32 val) {
+                   u32 mask = CommandProcessor::GetPhysicalAddressMask(system.IsWii()) & 0xFFFFFFE0;
+                   auto& processor_interface = system.GetProcessorInterface();
+                   processor_interface.m_fifo_cpu_write_pointer = val & mask;
+                 }));
 
   mmio->Register(base | PI_FIFO_RESET, MMIO::InvalidRead<u32>(),
                  MMIO::ComplexWrite<u32>([](Core::System& system, u32, u32 val) {
@@ -116,6 +135,13 @@ void ProcessorInterfaceManager::RegisterMMIO(MMIO::Mapping* mmio, u32 base)
                    }
                  }));
 
+  // TODO: Use the ErrorCause enum instead.
+  mmio->Register(base | PI_ERROR_CAUSE, MMIO::DirectRead<u32>(&m_error_cause),
+                 MMIO::DirectWrite<u32>(&m_error_cause, 0x00000007));
+
+  mmio->Register(base | PI_ERROR_ADDRESS, MMIO::DirectRead<u32>(&m_error_address),
+                 MMIO::InvalidWrite<u32>());
+
   mmio->Register(base | PI_RESET_CODE, MMIO::ComplexRead<u32>([](Core::System& system, u32) {
                    auto& processor_interface = system.GetProcessorInterface();
                    DEBUG_LOG_FMT(PROCESSORINTERFACE, "Read PI_RESET_CODE: {:08x}",
@@ -133,9 +159,15 @@ void ProcessorInterfaceManager::RegisterMMIO(MMIO::Mapping* mmio, u32 base)
                    }
                  }));
 
+  mmio->Register(base | PI_UNKNOWN, MMIO::DirectRead<u32>(&m_unknown),
+                 MMIO::DirectWrite<u32>(&m_unknown, 0x000003FF));
+
   mmio->Register(base | PI_FLIPPER_REV, MMIO::Constant<u32>(FLIPPER_REV_C),
                  MMIO::InvalidWrite<u32>());
 
+  mmio->Register(base | PI_FLIPPER_BUS_STRENGTH, MMIO::DirectRead<u32>(&m_flipper_bus_strength),
+                 MMIO::DirectWrite<u32>(&m_flipper_bus_strength, 0x07FFFFFF));
+
   // 16 bit reads are based on 32 bit reads.
   for (u32 i = 0; i < 0x1000; i += 4)
   {
diff --git a/Source/Core/Core/HW/ProcessorInterface.h b/Source/Core/Core/HW/ProcessorInterface.h
index 6387634843..4934147609 100644
--- a/Source/Core/Core/HW/ProcessorInterface.h
+++ b/Source/Core/Core/HW/ProcessorInterface.h
@@ -55,9 +55,27 @@ enum
   PI_FIFO_END = 0x10,
   PI_FIFO_WPTR = 0x14,
   PI_FIFO_RESET = 0x18,  // Used by GXAbortFrame
+  PI_ERROR_CAUSE = 0x1C,
+  PI_ERROR_ADDRESS = 0x20,
   PI_RESET_CODE = 0x24,
+  PI_UNKNOWN = 0x28,
   PI_FLIPPER_REV = 0x2C,
-  PI_FLIPPER_UNK = 0x30  // BS1 writes 0x0245248A to it - prolly some bootstrap thing
+  PI_FLIPPER_BUS_STRENGTH = 0x30  // BS1 writes 0x0245248A to it - controls the strength of the
+                                  // signal on the bus.  0 means the bus is dead and Flipper will
+                                  // not respond any longer, increasing it from the default value
+                                  // can reduce the noise in the Game Boy Player.
+};
+
+enum ErrorCause : u32
+{
+  NoError = 0,
+  MisalignedAddress = 1,
+  IncorrectTransferType = 2,
+  UnsupportedTransferSize = 3,
+  AddressOutOfRange = 4,
+  WriteToROM = 5,
+  ReadFromGXFIFO = 6,
+  Reserved = 7,
 };
 
 class ProcessorInterfaceManager
@@ -92,6 +110,11 @@ public:
   u32 m_fifo_cpu_end = 0;
   u32 m_fifo_cpu_write_pointer = 0;
 
+  u32 m_error_cause = 0;
+  u32 m_error_address = 0;
+  u32 m_unknown = 0x000001FF;
+  u32 m_flipper_bus_strength = 0x02492492;
+
 private:
   // Let the PPC know that an external exception is set/cleared
   void UpdateException();
diff --git a/Source/Core/Core/State.cpp b/Source/Core/Core/State.cpp
index 040c60f6ab..345e1537e5 100644
--- a/Source/Core/Core/State.cpp
+++ b/Source/Core/Core/State.cpp
@@ -96,7 +96,7 @@ struct CompressAndDumpStateArgs
 static Common::WorkQueueThreadSP<CompressAndDumpStateArgs> s_compress_and_dump_thread;
 
 // Don't forget to increase this after doing changes on the savestate system
-constexpr u32 STATE_VERSION = 191;  // Last changed in PR 14668
+constexpr u32 STATE_VERSION = 192;  // Last changed in PR 14646
 
 // Increase this if the StateExtendedHeader definition changes
 constexpr u32 EXTENDED_HEADER_VERSION = 1;  // Last changed in PR 12217