This thing really needs a rework...

src/core/vixen/hw/ata/ata_channel.cpp

@@ -194,11 +194,15 @@ void ATAChannel::WriteCommand(uint8_t value) {
     auto dev = m_devs[devIndex];
 
     // Check that there is no command in progress
+    // Use double-checked locking to avoid locking when there is no command (the common case)
     if (m_currentCommand != nullptr) {
-        log_warning("ATAChannel::WriteCommand:  Trying to run command while another command is in progress\n", value);
-        m_regs.status |= StError;
-        SetInterrupt(true);
-        return;
+        std::lock_guard<std::mutex> lk(m_commandMutex);
+        if (m_currentCommand != nullptr) {
+            log_warning("ATAChannel::WriteCommand:  Trying to run command while another command is in progress\n", value);
+            m_regs.status |= StError;
+            SetInterrupt(true);
+            return;
+        }
     }
 
     // Check that the command has a factory associated with it
@@ -209,7 +213,7 @@ void ATAChannel::WriteCommand(uint8_t value) {
         return;
     }
 
-    //log_spew("ATAChannel::WriteCommand:  Processing command 0x%x for channel %d, device %d\n", cmd, m_channel, devIndex);
+    log_spew("ATAChannel::WriteCommand:  Processing command 0x%x for channel %d, device %d\n", cmd, m_channel, devIndex);
 
     // Instantiate the command
     auto factory = kCmdFactories.at(cmd);
@@ -238,9 +242,13 @@ DMATransferResult ATAChannel::ReadDMA(uint8_t *dstBuffer, uint32_t readLen) {
     }
 
     // Read data for the command and clear it if finished
+    std::lock_guard<std::mutex> lk(m_commandMutex);
     m_currentCommand->ReadData(dstBuffer, readLen);
     if (m_currentCommand->IsFinished()) {
         log_spew("ATAChannel::ReadDMA:  Finished processing command for channel %d\n", m_channel);
+        if (m_currentCommand == nullptr) {
+            log_spew("This thing broke :(\n", m_channel);
+        }
         delete m_currentCommand;
         m_currentCommand = nullptr;
         return DMATransferEnd;
@@ -258,9 +266,13 @@ DMATransferResult ATAChannel::WriteDMA(uint8_t *srcBuffer, uint32_t writeLen) {
     }
 
     // Write data for the command and clear it if finished
+    std::lock_guard<std::mutex> lk(m_commandMutex);
     m_currentCommand->WriteData(srcBuffer, writeLen);
     if (m_currentCommand->IsFinished()) {
         log_spew("ATAChannel::WriteDMA:  Finished processing command for channel %d\n", m_channel);
+        if (m_currentCommand == nullptr) {
+            log_spew("This thing broke :(\n", m_channel);
+        }
         delete m_currentCommand;
         m_currentCommand = nullptr;
         return DMATransferEnd;
@@ -271,7 +283,7 @@ DMATransferResult ATAChannel::WriteDMA(uint8_t *srcBuffer, uint32_t writeLen) {
 
 void ATAChannel::SetInterrupt(bool asserted) {
     if (asserted != m_interrupt && m_regs.AreInterruptsEnabled()) {
-        log_spew("ATAChannel::SetInterrupt:  %s interrupt for channel %d\n", (asserted ? "asserting" : "negating"), m_channel);
+        //log_spew("ATAChannel::SetInterrupt:  %s interrupt for channel %d\n", (asserted ? "asserting" : "negating"), m_channel);
         m_interrupt = asserted;
         for (auto it = m_intrHooks.begin(); it != m_intrHooks.end(); it++) {
             (*it)->OnChange(asserted);

src/core/vixen/hw/ata/ata_channel.h

@@ -13,6 +13,8 @@
 
 #include <cstdint>
 
+#include <mutex>
+
 #include "vixen/cpu.h"
 #include "../basic/irq.h"
 #include "../basic/interrupt.h"
@@ -103,7 +105,9 @@ class ATAChannel {
     // ----- State ------------------------------------------------------------
 
     bool m_interrupt = false;  // [5.2.9] INTRQ (Device Interrupt)
+
     cmd::IATACommand *m_currentCommand;
+    std::mutex m_commandMutex;
 
     // ----- Interrupt handling -----------------------------------------------
 

src/core/vixen/hw/ata/cmds/proto_packet.cpp

@@ -109,6 +109,7 @@ void PacketProtocolCommand::ReadData(uint8_t *value, uint32_t size) {
     }
 
     // Copy from buffer to value
+    // TODO: handle partial transfers
     memcpy(value, m_packetDataBuffer + m_packetDataPos, size);
     m_packetDataPos += size;
 
@@ -148,6 +149,7 @@ void PacketProtocolCommand::WriteData(uint8_t *value, uint32_t size) {
     }
     else {
         // Writing the data requested by the Packet command
+        // TODO: handle partial transfers
         memcpy(m_packetDataBuffer + m_packetDataPos, value, size);
         m_packetDataPos += size;
 
@@ -379,6 +381,7 @@ void PacketProtocolCommand::HandleProtocolTail(bool hasError) {
     m_regs.status |= StReady;
     m_regs.status &= ~StBusy;
     m_interrupt.Assert();
+    log_spew("PacketProtocolCommand::HandleProtocolTail:  Packet command finished\n");
     Finish();
 }
 

src/core/vixen/hw/ata/drvs/drv_vdvd_base.cpp

@@ -166,7 +166,7 @@ bool BaseDVDDriveATADeviceDriver::ValidateCommand(PacketInformation& packetInfo)
         packetInfo.transferSize = (uint32_t)B2L16(packetInfo.cdb.read10.length) * kDVDSectorSize;
         return true;
     case OpReadDVDStructure:
-        packetInfo.transferSize = B2L16(packetInfo.cdb.readDVDStructure.length);
+        packetInfo.transferSize = kDVDSectorSize;
         return true;
     default:
         return true;

src/core/vixen/hw/ata/drvs/drv_vdvd_image.cpp

@@ -199,7 +199,7 @@ bool ImageDVDDriveATADeviceDriver::ProcessATAPIPacketDataRead(PacketInformation&
     case OpReadDVDStructure:
     {
         ReadDVDStructureData *dvdData = reinterpret_cast<ReadDVDStructureData *>(packetDataBuffer);
-        memset(dvdData, 0, sizeof(ReadDVDStructureData));
+        memset(dvdData, 0, kDVDSectorSize);
         switch (packetInfo.cdb.readDVDStructure.format) {
         case DVDFmtPhysical:
             L2B16(dvdData->dataLength, (uint16_t)sizeof(ReadDVDStructureData::physicalFormatInformation));
@@ -218,7 +218,7 @@ bool ImageDVDDriveATADeviceDriver::ProcessATAPIPacketDataRead(PacketInformation&
             L2B24(dvdData->physicalFormatInformation.layer0EndingSector, 0);
             dvdData->physicalFormatInformation.burstCuttingArea = 0;
 
-            *packetDataSize = sizeof(ReadDVDStructureData);
+            *packetDataSize = kDVDSectorSize;
             return true;
         default:
             log_debug("ImageDVDDriveATADeviceDriver::ProcessATAPIPacketDataRead:  Unimplemented format 0x%x for READ DVD STRUCTURE\n", packetInfo.cdb.readDVDStructure.format);

src/core/vixen/hw/pci/bmide_channel.h

@@ -76,7 +76,7 @@ class BMIDEChannel {
         void OnChange(bool asserted) override {
             if (asserted) {
                 m_channel.m_status |= StInterrupt;
-                log_spew("BM IDE channel %d:  Interrupt asserted\n", m_channel.m_channel);
+                //log_spew("BM IDE channel %d:  Interrupt asserted\n", m_channel.m_channel);
             }
         }