LibUSBBluetoothAdapter: Add SendBlockingCommand function.

Source/Core/Core/IOS/USB/Bluetooth/LibUSBBluetoothAdapter.cpp

@@ -14,6 +14,7 @@
 #include <fmt/format.h>
 #include <libusb.h>
 
+#include "Common/BitUtils.h"
 #include "Common/MsgHandler.h"
 
 #include "Core/Config/MainSettings.h"
@@ -62,6 +63,11 @@ bool LibUSBBluetoothAdapter::IsWiiBTModule() const
   return m_is_wii_bt_module;
 }
 
+bool LibUSBBluetoothAdapter::AreCommandsPendingResponse() const
+{
+  return !m_pending_hci_transfers.empty() || !m_unacknowledged_commands.empty();
+}
+
 bool LibUSBBluetoothAdapter::HasConfiguredBluetoothDevice()
 {
   const int configured_vid = Config::Get(Config::MAIN_BLUETOOTH_PASSTHROUGH_VID);
@@ -159,7 +165,7 @@ LibUSBBluetoothAdapter::~LibUSBBluetoothAdapter()
     return;
 
   // Wait for completion (or time out) of all HCI commands.
-  while (!m_pending_hci_transfers.empty() && !m_unacknowledged_commands.empty())
+  while (AreCommandsPendingResponse())
   {
     (void)ReceiveHCIEvent();
     Common::YieldCPU();
@@ -394,6 +400,50 @@ void LibUSBBluetoothAdapter::SendControlTransfer(std::span<const u8> data)
   ScheduleControlTransfer(REQUEST_TYPE, 0, 0, 0, data, Clock::now());
 }
 
+bool LibUSBBluetoothAdapter::SendBlockingCommand(std::span<const u8> data, std::span<u8> response)
+{
+  SendControlTransfer(data);
+
+  const hci_cmd_hdr_t cmd = Common::BitCastPtr<hci_cmd_hdr_t>(data.data());
+
+  while (AreCommandsPendingResponse())
+  {
+    const auto event = ReceiveHCIEvent();
+
+    if (event.empty())
+    {
+      Common::YieldCPU();
+      continue;
+    }
+
+    if (event[0] != HCI_EVENT_COMMAND_COMPL)
+      continue;
+
+    if (event.size() < sizeof(hci_event_hdr_t) + sizeof(hci_command_compl_ep))
+    {
+      ERROR_LOG_FMT(IOS_WIIMOTE, "Undersized hci_command_compl_ep");
+      continue;
+    }
+
+    const hci_command_compl_ep compl_event =
+        Common::BitCastPtr<hci_command_compl_ep>(event.data() + sizeof(hci_event_hdr_t));
+    if (compl_event.opcode != cmd.opcode)
+      continue;
+
+    if (event.size() < sizeof(hci_event_hdr_t) + sizeof(hci_command_compl_ep) + response.size())
+    {
+      ERROR_LOG_FMT(IOS_WIIMOTE, "Undersized command result");
+      break;
+    }
+
+    std::copy_n(event.data() + sizeof(hci_event_hdr_t) + sizeof(hci_command_compl_ep),
+                response.size(), response.data());
+    return true;
+  }
+
+  return false;
+}
+
 void LibUSBBluetoothAdapter::StartInputTransfers()
 {
   constexpr auto callback = LibUSBMemFunCallback<&LibUSBBluetoothAdapter::HandleInputTransfer>();

Source/Core/Core/IOS/USB/Bluetooth/LibUSBBluetoothAdapter.h

@@ -53,6 +53,11 @@ public:
   // Schedule a transfer to be submitted as soon as possible.
   void SendControlTransfer(std::span<const u8> data);
 
+  // Blocks and eats events until a command complete event of the correct opcode is received.
+  // Returns true on success or false on error or timeout.
+  // The written response does not include the event header or command complete data.
+  bool SendBlockingCommand(std::span<const u8> data, std::span<u8> response);
+
   bool IsWiiBTModule() const;
 
 private:
@@ -122,6 +127,7 @@ private:
   std::deque<OutstandingCommand> m_unacknowledged_commands;
 
   bool IsControllerReadyForCommand() const;
+  bool AreCommandsPendingResponse() const;
 
   // Give the transfer to the worker and track the command appropriately.
   // This should only be used when IsControllerReadyForCommand is true.