From 7cc77b10ed5e59db42947128d8715ff415bbe8d7 Mon Sep 17 00:00:00 2001
From: Flyinghead <raphael.jean@gmail.com>
Date: Thu, 7 Dec 2023 16:14:10 +0100
Subject: [PATCH] naomi: schedule end of cart dma

Set to 20 MB/s to fix meltyb satsuki vs kouma hang when starting fight
Issue #1255
---
 core/hw/naomi/naomi.cpp      | 64 +++++++++++++++++++++++++-----------
 core/serialize.h             |  3 +-
 tests/src/serialize_test.cpp |  2 +-
 3 files changed, 47 insertions(+), 22 deletions(-)

diff --git a/core/hw/naomi/naomi.cpp b/core/hw/naomi/naomi.cpp
index e974a8ca97..204ae63822 100644
--- a/core/hw/naomi/naomi.cpp
+++ b/core/hw/naomi/naomi.cpp
@@ -45,6 +45,8 @@ static X76F100SerialFlash romSerialId;
 static u8 midiTxBuf[4];
 static u32 midiTxBufIndex;
 
+static int dmaSchedId = -1;
+
 void NaomiBoardIDWrite(const u16 data)
 {
 	// bit 2: clock
@@ -109,6 +111,33 @@ void WriteMem_naomi(u32 address, u32 data, u32 size)
 		CurrentCartridge->WriteMem(address, data, size);
 }
 
+static int naomiDmaSched(int tag, int sch_cycl, int jitter, void *arg)
+{
+	u32 start = SB_GDSTAR & 0x1FFFFFE0;
+	u32 len = (SB_GDLEN + 31) & ~31;
+	SB_GDLEND = 0;
+	while (len > 0)
+	{
+		u32 block_len = len;
+		void* ptr = CurrentCartridge->GetDmaPtr(block_len);
+		if (block_len == 0)
+		{
+			INFO_LOG(NAOMI, "Aborted DMA transfer. Read past end of cart?");
+			break;
+		}
+		WriteMemBlock_nommu_ptr(start, (u32*)ptr, block_len);
+		CurrentCartridge->AdvancePtr(block_len);
+		len -= block_len;
+		start += block_len;
+		SB_GDLEND += block_len;
+	}
+	SB_GDSTARD = start;
+	SB_GDST = 0;
+	asic_RaiseInterrupt(holly_GDROM_DMA);
+
+	return 0;
+}
+
 //Dma Start
 static void Naomi_DmaStart(u32 addr, u32 data)
 {
@@ -123,29 +152,16 @@ static void Naomi_DmaStart(u32 addr, u32 data)
 	if (multiboard != nullptr && multiboard->dmaStart())
 	{
 	}
-	else if (!m3comm.DmaStart(addr, data) && CurrentCartridge != NULL)
+	else if (!m3comm.DmaStart(addr, data) && CurrentCartridge != nullptr)
 	{
 		DEBUG_LOG(NAOMI, "NAOMI-DMA start addr %08X len %d", SB_GDSTAR, SB_GDLEN);
 		verify(1 == SB_GDDIR);
-		u32 start = SB_GDSTAR & 0x1FFFFFE0;
-		u32 len = (SB_GDLEN + 31) & ~31;
-		SB_GDLEND = 0;
-		while (len > 0)
-		{
-			u32 block_len = len;
-			void* ptr = CurrentCartridge->GetDmaPtr(block_len);
-			if (block_len == 0)
-			{
-				INFO_LOG(NAOMI, "Aborted DMA transfer. Read past end of cart?");
-				break;
-			}
-			WriteMemBlock_nommu_ptr(start, (u32*)ptr, block_len);
-			CurrentCartridge->AdvancePtr(block_len);
-			len -= block_len;
-			start += block_len;
-			SB_GDLEND += block_len;
-		}
-		SB_GDSTARD = start;
+		SB_GDST = 1;
+		// Max G1 bus rate: 50 MHz x 16 bits
+		// SH4_access990312_e.xls: 14.4 MB/s from GD-ROM to system RAM
+		// Here: 20 MB/s
+		sh4_sched_request(dmaSchedId, SB_GDLEN * 10);
+		return;
 	}
 	else
 	{
@@ -180,6 +196,8 @@ void naomi_reg_Init()
 	};
 	romSerialId.setData(romSerialData);
 	mainSerialId.setData(romSerialData);
+	if (dmaSchedId == -1)
+		dmaSchedId = sh4_sched_register(0, naomiDmaSched);
 }
 
 void setGameSerialId(const u8 *data)
@@ -194,6 +212,9 @@ void naomi_reg_Term()
 	multiboard = nullptr;
 	m3comm.closeNetwork();
 	networkOutput.term();
+	if (dmaSchedId != -1)
+		sh4_sched_unregister(dmaSchedId);
+	dmaSchedId = -1;
 }
 
 void naomi_reg_Reset(bool hard)
@@ -345,6 +366,7 @@ void naomi_Serialize(Serializer& ser)
 	ser << midiTxBufIndex;
 	// TODO serialize m3comm?
 	ser << ffbCalibrating;
+	sh4_sched_serialize(ser, dmaSchedId);
 }
 void naomi_Deserialize(Deserializer& deser)
 {
@@ -404,6 +426,8 @@ void naomi_Deserialize(Deserializer& deser)
 		deser >> ffbCalibrating;
 	else
 		ffbCalibrating = false;
+	if (deser.version() >= Deserializer::V45)
+		sh4_sched_deserialize(deser, dmaSchedId);
 }
 
 static void midiSend(u8 b1, u8 b2, u8 b3)
diff --git a/core/serialize.h b/core/serialize.h
index cdde0fd07b..9295f36d1f 100644
--- a/core/serialize.h
+++ b/core/serialize.h
@@ -70,7 +70,8 @@ class SerializeBase
 		V42,
 		V43,
 		V44,
-		Current = V44,
+		V45,
+		Current = V45,
 
 		Next = Current + 1,
 	};
diff --git a/tests/src/serialize_test.cpp b/tests/src/serialize_test.cpp
index 137d0d2ea1..1415b19eb1 100644
--- a/tests/src/serialize_test.cpp
+++ b/tests/src/serialize_test.cpp
@@ -32,7 +32,7 @@ TEST_F(SerializeTest, SizeTest)
 	std::vector<char> data(30000000);
 	Serializer ser(data.data(), data.size());
 	dc_serialize(ser);
-	ASSERT_EQ(28191413u, ser.size());
+	ASSERT_EQ(28191425u, ser.size());
 }