system/gd/hci/hci_layer.cc - platform/packages/modules/Bluetooth - Git at Google

 /*
  * Copyright 2019 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "hci/hci_layer.h"

 #include "common/bind.h"
 #include "common/callback.h"
 #include "os/alarm.h"
 #include "os/queue.h"
 #include "packet/packet_builder.h"

 namespace bluetooth {
 namespace hci {
 using bluetooth::common::Bind;
 using bluetooth::common::BindOn;
 using bluetooth::common::BindOnce;
 using bluetooth::common::Callback;
 using bluetooth::common::Closure;
 using bluetooth::common::OnceCallback;
 using bluetooth::common::OnceClosure;
 using bluetooth::hci::CommandCompleteView;
 using bluetooth::hci::CommandPacketBuilder;
 using bluetooth::hci::CommandStatusView;
 using bluetooth::hci::EventPacketView;
 using bluetooth::hci::LeMetaEventView;
 using bluetooth::os::Handler;
 using common::BidiQueue;
 using common::BidiQueueEnd;
 using hci::OpCode;
 using hci::ResetCompleteView;
 using os::Alarm;
 using os::Handler;

 static void fail_if_reset_complete_not_success(CommandCompleteView complete) {
   auto reset_complete = ResetCompleteView::Create(complete);
   ASSERT(reset_complete.IsValid());
   ASSERT(reset_complete.GetStatus() == ErrorCode::SUCCESS);
 }

 static void on_hci_timeout(OpCode op_code) {
   ASSERT_LOG(false, "Timed out waiting for 0x%02hx (%s)", op_code, OpCodeText(op_code).c_str());
 }

 template <typename T>
 class EventHandler {
  public:
   EventHandler() : callback(), handler(nullptr) {}
   EventHandler(Callback<void(T)> on_event, Handler* on_event_handler)
       : callback(std::move(on_event)), handler(on_event_handler) {}
   Callback<void(T)> callback;
   Handler* handler;

   void Post(T event) {
     if (handler != nullptr) {
       handler->Post(BindOnce(callback, event));
     }
   }
 };

 class CommandQueueEntry {
  public:
   CommandQueueEntry(std::unique_ptr<CommandPacketBuilder> command_packet,
                     OnceCallback<void(CommandCompleteView)> on_complete_function, Handler* handler)
       : command(std::move(command_packet)), waiting_for_status_(false), on_complete(std::move(on_complete_function)),
         caller_handler(handler) {}

   CommandQueueEntry(std::unique_ptr<CommandPacketBuilder> command_packet,
                     OnceCallback<void(CommandStatusView)> on_status_function, Handler* handler)
       : command(std::move(command_packet)), waiting_for_status_(true), on_status(std::move(on_status_function)),
         caller_handler(handler) {}

   std::unique_ptr<CommandPacketBuilder> command;
   bool waiting_for_status_;
   OnceCallback<void(CommandStatusView)> on_status;
   OnceCallback<void(CommandCompleteView)> on_complete;
   Handler* caller_handler;
 };

 template <typename T>
 class CommandInterfaceImpl : public CommandInterface<T> {
  public:
   explicit CommandInterfaceImpl(HciLayer& hci) : hci_(hci) {}
   ~CommandInterfaceImpl() override = default;

   void EnqueueCommand(std::unique_ptr<T> command, common::OnceCallback<void(CommandCompleteView)> on_complete,
                       os::Handler* handler) override {
     hci_.EnqueueCommand(std::move(command), std::move(on_complete), handler);
   }

   void EnqueueCommand(std::unique_ptr<T> command, common::OnceCallback<void(CommandStatusView)> on_status,
                       os::Handler* handler) override {
     hci_.EnqueueCommand(std::move(command), std::move(on_status), handler);
   }
   HciLayer& hci_;
 };

 struct HciLayer::impl {
   impl(HciLayer& module) : hal_(nullptr), module_(module) {}

   void Start(hal::HciHal* hal) {
     hal_ = hal;
     hci_timeout_alarm_ = new Alarm(module_.GetHandler());

     auto queue_end = acl_queue_.GetDownEnd();
     Handler* handler = module_.GetHandler();
     queue_end->RegisterDequeue(handler, BindOn(this, &impl::dequeue_and_send_acl));
     module_.RegisterEventHandler(EventCode::COMMAND_COMPLETE, BindOn(this, &impl::command_complete_callback), handler);
     module_.RegisterEventHandler(EventCode::COMMAND_STATUS, BindOn(this, &impl::command_status_callback), handler);
     module_.RegisterEventHandler(EventCode::LE_META_EVENT, BindOn(this, &impl::le_meta_event_callback), handler);
     // TODO find the right place
     module_.RegisterEventHandler(EventCode::PAGE_SCAN_REPETITION_MODE_CHANGE, BindOn(this, &impl::drop), handler);
     module_.RegisterEventHandler(EventCode::MAX_SLOTS_CHANGE, BindOn(this, &impl::drop), handler);
     module_.RegisterEventHandler(EventCode::VENDOR_SPECIFIC, BindOn(this, &impl::drop), handler);

     module_.EnqueueCommand(ResetBuilder::Create(), BindOnce(&fail_if_reset_complete_not_success), handler);
   }

   void drop(EventPacketView) {}

   void dequeue_and_send_acl() {
     auto packet = acl_queue_.GetDownEnd()->TryDequeue();
     std::vector<uint8_t> bytes;
     BitInserter bi(bytes);
     packet->Serialize(bi);
     hal_->sendAclData(bytes);
   }

   void Stop() {
     acl_queue_.GetDownEnd()->UnregisterDequeue();
     incoming_acl_packet_buffer_.Clear();
     delete hci_timeout_alarm_;
     command_queue_.clear();
     hal_ = nullptr;
   }

   void send_sco(std::unique_ptr<hci::BasePacketBuilder> packet) {
     std::vector<uint8_t> bytes;
     BitInserter bi(bytes);
     packet->Serialize(bi);
     hal_->sendScoData(bytes);
   }

   void command_status_callback(EventPacketView event) {
     CommandStatusView status_view = CommandStatusView::Create(event);
     ASSERT(status_view.IsValid());
     command_credits_ = status_view.GetNumHciCommandPackets();
     OpCode op_code = status_view.GetCommandOpCode();
     if (op_code == OpCode::NONE) {
       send_next_command();
       return;
     }
     ASSERT_LOG(!command_queue_.empty(), "Unexpected status event with OpCode 0x%02hx (%s)", op_code,
                OpCodeText(op_code).c_str());
     ASSERT_LOG(waiting_command_ == op_code, "Waiting for 0x%02hx (%s), got 0x%02hx (%s)", waiting_command_,
                OpCodeText(waiting_command_).c_str(), op_code, OpCodeText(op_code).c_str());
     ASSERT_LOG(command_queue_.front().waiting_for_status_,
                "Waiting for command complete 0x%02hx (%s), got command status for 0x%02hx (%s)", waiting_command_,
                OpCodeText(waiting_command_).c_str(), op_code, OpCodeText(op_code).c_str());
     auto caller_handler = command_queue_.front().caller_handler;
     caller_handler->Post(BindOnce(std::move(command_queue_.front().on_status), std::move(status_view)));
     command_queue_.pop_front();
     waiting_command_ = OpCode::NONE;
     hci_timeout_alarm_->Cancel();
     send_next_command();
   }

   void command_complete_callback(EventPacketView event) {
     CommandCompleteView complete_view = CommandCompleteView::Create(event);
     ASSERT(complete_view.IsValid());
     command_credits_ = complete_view.GetNumHciCommandPackets();
     OpCode op_code = complete_view.GetCommandOpCode();
     if (op_code == OpCode::NONE) {
       send_next_command();
       return;
     }
     ASSERT_LOG(command_queue_.size() > 0, "Unexpected command complete with OpCode 0x%02hx (%s)", op_code,
                OpCodeText(op_code).c_str());
     ASSERT_LOG(waiting_command_ == op_code, "Waiting for 0x%02hx (%s), got 0x%02hx (%s)", waiting_command_,
                OpCodeText(waiting_command_).c_str(), op_code, OpCodeText(op_code).c_str());
     ASSERT_LOG(!command_queue_.front().waiting_for_status_,
                "Waiting for command status 0x%02hx (%s), got command complete for 0x%02hx (%s)", waiting_command_,
                OpCodeText(waiting_command_).c_str(), op_code, OpCodeText(op_code).c_str());
     auto caller_handler = command_queue_.front().caller_handler;
     caller_handler->Post(BindOnce(std::move(command_queue_.front().on_complete), complete_view));
     command_queue_.pop_front();
     waiting_command_ = OpCode::NONE;
     hci_timeout_alarm_->Cancel();
     send_next_command();
   }

   void le_meta_event_callback(EventPacketView event) {
     LeMetaEventView meta_event_view = LeMetaEventView::Create(event);
     ASSERT(meta_event_view.IsValid());
     SubeventCode subevent_code = meta_event_view.GetSubeventCode();
     ASSERT_LOG(subevent_handlers_.find(subevent_code) != subevent_handlers_.end(),
                "Unhandled le event of type 0x%02hhx (%s)", subevent_code, SubeventCodeText(subevent_code).c_str());
     subevent_handlers_[subevent_code].Post(meta_event_view);
   }

   void hci_event_received_handler(EventPacketView event) {
     EventCode event_code = event.GetEventCode();
     if (event_handlers_.find(event_code) == event_handlers_.end()) {
       LOG_DEBUG("Dropping unregistered event of type 0x%02hhx (%s)", event_code, EventCodeText(event_code).c_str());
       return;
     }
     event_handlers_[event_code].Post(event);
   }

   void handle_enqueue_command_with_complete(std::unique_ptr<CommandPacketBuilder> command,
                                             OnceCallback<void(CommandCompleteView)> on_complete, os::Handler* handler) {
     command_queue_.emplace_back(std::move(command), std::move(on_complete), handler);

     send_next_command();
   }

   void handle_enqueue_command_with_status(std::unique_ptr<CommandPacketBuilder> command,
                                           OnceCallback<void(CommandStatusView)> on_status, os::Handler* handler) {
     command_queue_.emplace_back(std::move(command), std::move(on_status), handler);

     send_next_command();
   }

   void send_next_command() {
     if (command_credits_ == 0) {
       return;
     }
     if (waiting_command_ != OpCode::NONE) {
       return;
     }
     if (command_queue_.size() == 0) {
       return;
     }
     std::shared_ptr<std::vector<uint8_t>> bytes = std::make_shared<std::vector<uint8_t>>();
     BitInserter bi(*bytes);
     command_queue_.front().command->Serialize(bi);
     hal_->sendHciCommand(*bytes);
     auto cmd_view = CommandPacketView::Create(bytes);
     ASSERT(cmd_view.IsValid());
     OpCode op_code = cmd_view.GetOpCode();
     waiting_command_ = op_code;
     command_credits_ = 0;  // Only allow one outstanding command
     hci_timeout_alarm_->Schedule(BindOnce(&on_hci_timeout, op_code), kHciTimeoutMs);
   }

   void handle_register_event_handler(EventCode event_code, Callback<void(EventPacketView)> event_handler,
                                      os::Handler* handler) {
     ASSERT_LOG(event_handlers_.count(event_code) == 0, "Can not register a second handler for event_code %02hhx (%s)",
                event_code, EventCodeText(event_code).c_str());
     event_handlers_[event_code] = EventHandler<EventPacketView>(event_handler, handler);
   }

   void handle_unregister_event_handler(EventCode event_code) {
     event_handlers_[event_code] = EventHandler<EventPacketView>();
   }

   void handle_register_le_event_handler(SubeventCode subevent_code, Callback<void(LeMetaEventView)> subevent_handler,
                                         os::Handler* handler) {
     ASSERT_LOG(subevent_handlers_.count(subevent_code) == 0,
                "Can not register a second handler for subevent_code %02hhx (%s)", subevent_code,
                SubeventCodeText(subevent_code).c_str());
     subevent_handlers_[subevent_code] = EventHandler<LeMetaEventView>(subevent_handler, handler);
   }

   void handle_unregister_le_event_handler(SubeventCode subevent_code) {
     subevent_handlers_[subevent_code] = EventHandler<LeMetaEventView>();
   }

   // The HAL
   hal::HciHal* hal_;

   // A reference to the HciLayer module
   HciLayer& module_;

   // Interfaces
   CommandInterfaceImpl<ConnectionManagementCommandBuilder> acl_connection_manager_interface_{module_};
   CommandInterfaceImpl<LeConnectionManagementCommandBuilder> le_acl_connection_manager_interface_{module_};
   CommandInterfaceImpl<SecurityCommandBuilder> security_interface{module_};
   CommandInterfaceImpl<LeSecurityCommandBuilder> le_security_interface{module_};
   CommandInterfaceImpl<LeAdvertisingCommandBuilder> le_advertising_interface{module_};
   CommandInterfaceImpl<LeScanningCommandBuilder> le_scanning_interface{module_};

   // Command Handling
   std::list<CommandQueueEntry> command_queue_;

   std::map<EventCode, EventHandler<EventPacketView>> event_handlers_;
   std::map<SubeventCode, EventHandler<LeMetaEventView>> subevent_handlers_;
   OpCode waiting_command_{OpCode::NONE};
   uint8_t command_credits_{1};  // Send reset first
   Alarm* hci_timeout_alarm_{nullptr};

   // Acl packets
   BidiQueue<AclPacketView, AclPacketBuilder> acl_queue_{3 /* TODO: Set queue depth */};
   os::EnqueueBuffer<AclPacketView> incoming_acl_packet_buffer_{acl_queue_.GetDownEnd()};
 };

 // All functions here are running on the HAL thread
 struct HciLayer::hal_callbacks : public hal::HciHalCallbacks {
   hal_callbacks(HciLayer& module) : module_(module) {}

   void hciEventReceived(hal::HciPacket event_bytes) override {
     auto packet = packet::PacketView<packet::kLittleEndian>(std::make_shared<std::vector<uint8_t>>(event_bytes));
     EventPacketView event = EventPacketView::Create(packet);
     ASSERT(event.IsValid());
     module_.CallOn(module_.impl_, &impl::hci_event_received_handler, std::move(event));
   }

   void aclDataReceived(hal::HciPacket data_bytes) override {
     auto packet =
         packet::PacketView<packet::kLittleEndian>(std::make_shared<std::vector<uint8_t>>(std::move(data_bytes)));
     AclPacketView acl = AclPacketView::Create(packet);
     module_.impl_->incoming_acl_packet_buffer_.Enqueue(std::make_unique<AclPacketView>(acl), module_.GetHandler());
   }

   void scoDataReceived(hal::HciPacket data_bytes) override {
     // Not implemented yet
   }

   HciLayer& module_;
 };

 HciLayer::HciLayer() : impl_(new impl(*this)), hal_callbacks_(new hal_callbacks(*this)) {}

 HciLayer::~HciLayer() {
   delete impl_;
   delete hal_callbacks_;
 }

 void HciLayer::EnqueueCommand(std::unique_ptr<CommandPacketBuilder> command,
                               common::OnceCallback<void(CommandCompleteView)> on_complete, os::Handler* handler) {
   CallOn(impl_, &impl::handle_enqueue_command_with_complete, std::move(command), std::move(on_complete),
          common::Unretained(handler));
 }

 void HciLayer::EnqueueCommand(std::unique_ptr<CommandPacketBuilder> command,
                               common::OnceCallback<void(CommandStatusView)> on_status, os::Handler* handler) {
   CallOn(impl_, &impl::handle_enqueue_command_with_status, std::move(command), std::move(on_status),
          common::Unretained(handler));
 }

 common::BidiQueueEnd<AclPacketBuilder, AclPacketView>* HciLayer::GetAclQueueEnd() {
   return impl_->acl_queue_.GetUpEnd();
 }

 void HciLayer::RegisterEventHandler(EventCode event_code, common::Callback<void(EventPacketView)> event_handler,
                                     os::Handler* handler) {
   CallOn(impl_, &impl::handle_register_event_handler, event_code, event_handler, common::Unretained(handler));
 }

 void HciLayer::UnregisterEventHandler(EventCode event_code) {
   CallOn(impl_, &impl::handle_unregister_event_handler, event_code);
 }

 void HciLayer::RegisterLeEventHandler(SubeventCode subevent_code, common::Callback<void(LeMetaEventView)> event_handler,
                                       os::Handler* handler) {
   CallOn(impl_, &impl::handle_register_le_event_handler, subevent_code, event_handler, common::Unretained(handler));
 }

 void HciLayer::UnregisterLeEventHandler(SubeventCode subevent_code) {
   CallOn(impl_, &impl::handle_unregister_le_event_handler, subevent_code);
 }

 AclConnectionInterface* HciLayer::GetAclConnectionInterface(common::Callback<void(EventPacketView)> event_handler,
                                                             common::Callback<void(uint16_t, ErrorCode)> on_disconnect,
                                                             os::Handler* handler) {
   for (const auto event : AclConnectionEvents) {
     RegisterEventHandler(event, event_handler, handler);
   }
   return &impl_->acl_connection_manager_interface_;
 }

 LeAclConnectionInterface* HciLayer::GetLeAclConnectionInterface(
     common::Callback<void(LeMetaEventView)> event_handler, common::Callback<void(uint16_t, ErrorCode)> on_disconnect,
     os::Handler* handler) {
   for (const auto event : LeConnectionManagementEvents) {
     RegisterLeEventHandler(event, event_handler, handler);
   }
   return &impl_->le_acl_connection_manager_interface_;
 }

 SecurityInterface* HciLayer::GetSecurityInterface(common::Callback<void(EventPacketView)> event_handler,
                                                   os::Handler* handler) {
   for (const auto event : SecurityEvents) {
     RegisterEventHandler(event, event_handler, handler);
   }
   return &impl_->security_interface;
 }

 LeSecurityInterface* HciLayer::GetLeSecurityInterface(common::Callback<void(LeMetaEventView)> event_handler,
                                                       os::Handler* handler) {
   for (const auto subevent : LeSecurityEvents) {
     RegisterLeEventHandler(subevent, event_handler, handler);
   }
   return &impl_->le_security_interface;
 }

 LeAdvertisingInterface* HciLayer::GetLeAdvertisingInterface(common::Callback<void(LeMetaEventView)> event_handler,
                                                             os::Handler* handler) {
   for (const auto subevent : LeAdvertisingEvents) {
     RegisterLeEventHandler(subevent, event_handler, handler);
   }
   return &impl_->le_advertising_interface;
 }

 LeScanningInterface* HciLayer::GetLeScanningInterface(common::Callback<void(LeMetaEventView)> event_handler,
                                                       os::Handler* handler) {
   for (const auto subevent : LeScanningEvents) {
     RegisterLeEventHandler(subevent, event_handler, handler);
   }
   return &impl_->le_scanning_interface;
 }

 const ModuleFactory HciLayer::Factory = ModuleFactory([]() { return new HciLayer(); });

 void HciLayer::ListDependencies(ModuleList* list) {
   list->add<hal::HciHal>();
 }

 void HciLayer::Start() {
   auto hal = GetDependency<hal::HciHal>();
   impl_->Start(hal);
   hal->registerIncomingPacketCallback(hal_callbacks_);
 }

 void HciLayer::Stop() {
   auto hal = GetDependency<hal::HciHal>();
   hal->unregisterIncomingPacketCallback();
   impl_->Stop();
 }

 }  // namespace hci
 }  // namespace bluetooth
	/*
	* Copyright 2019 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "hci/hci_layer.h"

	#include "common/bind.h"
	#include "common/callback.h"
	#include "os/alarm.h"
	#include "os/queue.h"
	#include "packet/packet_builder.h"

	namespace bluetooth {
	namespace hci {
	using bluetooth::common::Bind;
	using bluetooth::common::BindOn;
	using bluetooth::common::BindOnce;
	using bluetooth::common::Callback;
	using bluetooth::common::Closure;
	using bluetooth::common::OnceCallback;
	using bluetooth::common::OnceClosure;
	using bluetooth::hci::CommandCompleteView;
	using bluetooth::hci::CommandPacketBuilder;
	using bluetooth::hci::CommandStatusView;
	using bluetooth::hci::EventPacketView;
	using bluetooth::hci::LeMetaEventView;
	using bluetooth::os::Handler;
	using common::BidiQueue;
	using common::BidiQueueEnd;
	using hci::OpCode;
	using hci::ResetCompleteView;
	using os::Alarm;
	using os::Handler;

	static void fail_if_reset_complete_not_success(CommandCompleteView complete) {
	auto reset_complete = ResetCompleteView::Create(complete);
	ASSERT(reset_complete.IsValid());
	ASSERT(reset_complete.GetStatus() == ErrorCode::SUCCESS);
	}

	static void on_hci_timeout(OpCode op_code) {
	ASSERT_LOG(false, "Timed out waiting for 0x%02hx (%s)", op_code, OpCodeText(op_code).c_str());
	}

	template <typename T>
	class EventHandler {
	public:
	EventHandler() : callback(), handler(nullptr) {}
	EventHandler(Callback<void(T)> on_event, Handler* on_event_handler)
	: callback(std::move(on_event)), handler(on_event_handler) {}
	Callback<void(T)> callback;
	Handler* handler;

	void Post(T event) {
	if (handler != nullptr) {
	handler->Post(BindOnce(callback, event));
	}
	}
	};

	class CommandQueueEntry {
	public:
	CommandQueueEntry(std::unique_ptr<CommandPacketBuilder> command_packet,
	OnceCallback<void(CommandCompleteView)> on_complete_function, Handler* handler)
	: command(std::move(command_packet)), waiting_for_status_(false), on_complete(std::move(on_complete_function)),
	caller_handler(handler) {}

	CommandQueueEntry(std::unique_ptr<CommandPacketBuilder> command_packet,
	OnceCallback<void(CommandStatusView)> on_status_function, Handler* handler)
	: command(std::move(command_packet)), waiting_for_status_(true), on_status(std::move(on_status_function)),
	caller_handler(handler) {}

	std::unique_ptr<CommandPacketBuilder> command;
	bool waiting_for_status_;
	OnceCallback<void(CommandStatusView)> on_status;
	OnceCallback<void(CommandCompleteView)> on_complete;
	Handler* caller_handler;
	};

	template <typename T>
	class CommandInterfaceImpl : public CommandInterface<T> {
	public:
	explicit CommandInterfaceImpl(HciLayer& hci) : hci_(hci) {}
	~CommandInterfaceImpl() override = default;

	void EnqueueCommand(std::unique_ptr<T> command, common::OnceCallback<void(CommandCompleteView)> on_complete,
	os::Handler* handler) override {
	hci_.EnqueueCommand(std::move(command), std::move(on_complete), handler);
	}

	void EnqueueCommand(std::unique_ptr<T> command, common::OnceCallback<void(CommandStatusView)> on_status,
	os::Handler* handler) override {
	hci_.EnqueueCommand(std::move(command), std::move(on_status), handler);
	}
	HciLayer& hci_;
	};

	struct HciLayer::impl {
	impl(HciLayer& module) : hal_(nullptr), module_(module) {}

	void Start(hal::HciHal* hal) {
	hal_ = hal;
	hci_timeout_alarm_ = new Alarm(module_.GetHandler());

	auto queue_end = acl_queue_.GetDownEnd();
	Handler* handler = module_.GetHandler();
	queue_end->RegisterDequeue(handler, BindOn(this, &impl::dequeue_and_send_acl));
	module_.RegisterEventHandler(EventCode::COMMAND_COMPLETE, BindOn(this, &impl::command_complete_callback), handler);
	module_.RegisterEventHandler(EventCode::COMMAND_STATUS, BindOn(this, &impl::command_status_callback), handler);
	module_.RegisterEventHandler(EventCode::LE_META_EVENT, BindOn(this, &impl::le_meta_event_callback), handler);
	// TODO find the right place
	module_.RegisterEventHandler(EventCode::PAGE_SCAN_REPETITION_MODE_CHANGE, BindOn(this, &impl::drop), handler);
	module_.RegisterEventHandler(EventCode::MAX_SLOTS_CHANGE, BindOn(this, &impl::drop), handler);
	module_.RegisterEventHandler(EventCode::VENDOR_SPECIFIC, BindOn(this, &impl::drop), handler);

	module_.EnqueueCommand(ResetBuilder::Create(), BindOnce(&fail_if_reset_complete_not_success), handler);
	}

	void drop(EventPacketView) {}

	void dequeue_and_send_acl() {
	auto packet = acl_queue_.GetDownEnd()->TryDequeue();
	std::vector<uint8_t> bytes;
	BitInserter bi(bytes);
	packet->Serialize(bi);
	hal_->sendAclData(bytes);
	}

	void Stop() {
	acl_queue_.GetDownEnd()->UnregisterDequeue();
	incoming_acl_packet_buffer_.Clear();
	delete hci_timeout_alarm_;
	command_queue_.clear();
	hal_ = nullptr;
	}

	void send_sco(std::unique_ptr<hci::BasePacketBuilder> packet) {
	std::vector<uint8_t> bytes;
	BitInserter bi(bytes);
	packet->Serialize(bi);
	hal_->sendScoData(bytes);
	}

	void command_status_callback(EventPacketView event) {
	CommandStatusView status_view = CommandStatusView::Create(event);
	ASSERT(status_view.IsValid());
	command_credits_ = status_view.GetNumHciCommandPackets();
	OpCode op_code = status_view.GetCommandOpCode();
	if (op_code == OpCode::NONE) {
	send_next_command();
	return;
	}
	ASSERT_LOG(!command_queue_.empty(), "Unexpected status event with OpCode 0x%02hx (%s)", op_code,
	OpCodeText(op_code).c_str());
	ASSERT_LOG(waiting_command_ == op_code, "Waiting for 0x%02hx (%s), got 0x%02hx (%s)", waiting_command_,
	OpCodeText(waiting_command_).c_str(), op_code, OpCodeText(op_code).c_str());
	ASSERT_LOG(command_queue_.front().waiting_for_status_,
	"Waiting for command complete 0x%02hx (%s), got command status for 0x%02hx (%s)", waiting_command_,
	OpCodeText(waiting_command_).c_str(), op_code, OpCodeText(op_code).c_str());
	auto caller_handler = command_queue_.front().caller_handler;
	caller_handler->Post(BindOnce(std::move(command_queue_.front().on_status), std::move(status_view)));
	command_queue_.pop_front();
	waiting_command_ = OpCode::NONE;
	hci_timeout_alarm_->Cancel();
	send_next_command();
	}

	void command_complete_callback(EventPacketView event) {
	CommandCompleteView complete_view = CommandCompleteView::Create(event);
	ASSERT(complete_view.IsValid());
	command_credits_ = complete_view.GetNumHciCommandPackets();
	OpCode op_code = complete_view.GetCommandOpCode();
	if (op_code == OpCode::NONE) {
	send_next_command();
	return;
	}
	ASSERT_LOG(command_queue_.size() > 0, "Unexpected command complete with OpCode 0x%02hx (%s)", op_code,
	OpCodeText(op_code).c_str());
	ASSERT_LOG(waiting_command_ == op_code, "Waiting for 0x%02hx (%s), got 0x%02hx (%s)", waiting_command_,
	OpCodeText(waiting_command_).c_str(), op_code, OpCodeText(op_code).c_str());
	ASSERT_LOG(!command_queue_.front().waiting_for_status_,
	"Waiting for command status 0x%02hx (%s), got command complete for 0x%02hx (%s)", waiting_command_,
	OpCodeText(waiting_command_).c_str(), op_code, OpCodeText(op_code).c_str());
	auto caller_handler = command_queue_.front().caller_handler;
	caller_handler->Post(BindOnce(std::move(command_queue_.front().on_complete), complete_view));
	command_queue_.pop_front();
	waiting_command_ = OpCode::NONE;
	hci_timeout_alarm_->Cancel();
	send_next_command();
	}

	void le_meta_event_callback(EventPacketView event) {
	LeMetaEventView meta_event_view = LeMetaEventView::Create(event);
	ASSERT(meta_event_view.IsValid());
	SubeventCode subevent_code = meta_event_view.GetSubeventCode();
	ASSERT_LOG(subevent_handlers_.find(subevent_code) != subevent_handlers_.end(),
	"Unhandled le event of type 0x%02hhx (%s)", subevent_code, SubeventCodeText(subevent_code).c_str());
	subevent_handlers_[subevent_code].Post(meta_event_view);
	}

	void hci_event_received_handler(EventPacketView event) {
	EventCode event_code = event.GetEventCode();
	if (event_handlers_.find(event_code) == event_handlers_.end()) {
	LOG_DEBUG("Dropping unregistered event of type 0x%02hhx (%s)", event_code, EventCodeText(event_code).c_str());
	return;
	}
	event_handlers_[event_code].Post(event);
	}

	void handle_enqueue_command_with_complete(std::unique_ptr<CommandPacketBuilder> command,
	OnceCallback<void(CommandCompleteView)> on_complete, os::Handler* handler) {
	command_queue_.emplace_back(std::move(command), std::move(on_complete), handler);

	send_next_command();
	}

	void handle_enqueue_command_with_status(std::unique_ptr<CommandPacketBuilder> command,
	OnceCallback<void(CommandStatusView)> on_status, os::Handler* handler) {
	command_queue_.emplace_back(std::move(command), std::move(on_status), handler);

	send_next_command();
	}

	void send_next_command() {
	if (command_credits_ == 0) {
	return;
	}
	if (waiting_command_ != OpCode::NONE) {
	return;
	}
	if (command_queue_.size() == 0) {
	return;
	}
	std::shared_ptr<std::vector<uint8_t>> bytes = std::make_shared<std::vector<uint8_t>>();
	BitInserter bi(*bytes);
	command_queue_.front().command->Serialize(bi);
	hal_->sendHciCommand(*bytes);
	auto cmd_view = CommandPacketView::Create(bytes);
	ASSERT(cmd_view.IsValid());
	OpCode op_code = cmd_view.GetOpCode();
	waiting_command_ = op_code;
	command_credits_ = 0; // Only allow one outstanding command
	hci_timeout_alarm_->Schedule(BindOnce(&on_hci_timeout, op_code), kHciTimeoutMs);
	}

	void handle_register_event_handler(EventCode event_code, Callback<void(EventPacketView)> event_handler,
	os::Handler* handler) {
	ASSERT_LOG(event_handlers_.count(event_code) == 0, "Can not register a second handler for event_code %02hhx (%s)",
	event_code, EventCodeText(event_code).c_str());
	event_handlers_[event_code] = EventHandler<EventPacketView>(event_handler, handler);
	}

	void handle_unregister_event_handler(EventCode event_code) {
	event_handlers_[event_code] = EventHandler<EventPacketView>();
	}

	void handle_register_le_event_handler(SubeventCode subevent_code, Callback<void(LeMetaEventView)> subevent_handler,
	os::Handler* handler) {
	ASSERT_LOG(subevent_handlers_.count(subevent_code) == 0,
	"Can not register a second handler for subevent_code %02hhx (%s)", subevent_code,
	SubeventCodeText(subevent_code).c_str());
	subevent_handlers_[subevent_code] = EventHandler<LeMetaEventView>(subevent_handler, handler);
	}

	void handle_unregister_le_event_handler(SubeventCode subevent_code) {
	subevent_handlers_[subevent_code] = EventHandler<LeMetaEventView>();
	}

	// The HAL
	hal::HciHal* hal_;

	// A reference to the HciLayer module
	HciLayer& module_;

	// Interfaces
	CommandInterfaceImpl<ConnectionManagementCommandBuilder> acl_connection_manager_interface_{module_};
	CommandInterfaceImpl<LeConnectionManagementCommandBuilder> le_acl_connection_manager_interface_{module_};
	CommandInterfaceImpl<SecurityCommandBuilder> security_interface{module_};
	CommandInterfaceImpl<LeSecurityCommandBuilder> le_security_interface{module_};
	CommandInterfaceImpl<LeAdvertisingCommandBuilder> le_advertising_interface{module_};
	CommandInterfaceImpl<LeScanningCommandBuilder> le_scanning_interface{module_};

	// Command Handling
	std::list<CommandQueueEntry> command_queue_;

	std::map<EventCode, EventHandler<EventPacketView>> event_handlers_;
	std::map<SubeventCode, EventHandler<LeMetaEventView>> subevent_handlers_;
	OpCode waiting_command_{OpCode::NONE};
	uint8_t command_credits_{1}; // Send reset first
	Alarm* hci_timeout_alarm_{nullptr};

	// Acl packets
	BidiQueue<AclPacketView, AclPacketBuilder> acl_queue_{3 /* TODO: Set queue depth */};
	os::EnqueueBuffer<AclPacketView> incoming_acl_packet_buffer_{acl_queue_.GetDownEnd()};
	};

	// All functions here are running on the HAL thread
	struct HciLayer::hal_callbacks : public hal::HciHalCallbacks {
	hal_callbacks(HciLayer& module) : module_(module) {}

	void hciEventReceived(hal::HciPacket event_bytes) override {
	auto packet = packet::PacketView<packet::kLittleEndian>(std::make_shared<std::vector<uint8_t>>(event_bytes));
	EventPacketView event = EventPacketView::Create(packet);
	ASSERT(event.IsValid());
	module_.CallOn(module_.impl_, &impl::hci_event_received_handler, std::move(event));
	}

	void aclDataReceived(hal::HciPacket data_bytes) override {
	auto packet =
	packet::PacketView<packet::kLittleEndian>(std::make_shared<std::vector<uint8_t>>(std::move(data_bytes)));
	AclPacketView acl = AclPacketView::Create(packet);
	module_.impl_->incoming_acl_packet_buffer_.Enqueue(std::make_unique<AclPacketView>(acl), module_.GetHandler());
	}

	void scoDataReceived(hal::HciPacket data_bytes) override {
	// Not implemented yet
	}

	HciLayer& module_;
	};

	HciLayer::HciLayer() : impl_(new impl(this)), hal_callbacks_(new hal_callbacks(this)) {}

	HciLayer::~HciLayer() {
	delete impl_;
	delete hal_callbacks_;
	}

	void HciLayer::EnqueueCommand(std::unique_ptr<CommandPacketBuilder> command,
	common::OnceCallback<void(CommandCompleteView)> on_complete, os::Handler* handler) {
	CallOn(impl_, &impl::handle_enqueue_command_with_complete, std::move(command), std::move(on_complete),
	common::Unretained(handler));
	}

	void HciLayer::EnqueueCommand(std::unique_ptr<CommandPacketBuilder> command,
	common::OnceCallback<void(CommandStatusView)> on_status, os::Handler* handler) {
	CallOn(impl_, &impl::handle_enqueue_command_with_status, std::move(command), std::move(on_status),
	common::Unretained(handler));
	}

	common::BidiQueueEnd<AclPacketBuilder, AclPacketView>* HciLayer::GetAclQueueEnd() {
	return impl_->acl_queue_.GetUpEnd();
	}

	void HciLayer::RegisterEventHandler(EventCode event_code, common::Callback<void(EventPacketView)> event_handler,
	os::Handler* handler) {
	CallOn(impl_, &impl::handle_register_event_handler, event_code, event_handler, common::Unretained(handler));
	}

	void HciLayer::UnregisterEventHandler(EventCode event_code) {
	CallOn(impl_, &impl::handle_unregister_event_handler, event_code);
	}

	void HciLayer::RegisterLeEventHandler(SubeventCode subevent_code, common::Callback<void(LeMetaEventView)> event_handler,
	os::Handler* handler) {
	CallOn(impl_, &impl::handle_register_le_event_handler, subevent_code, event_handler, common::Unretained(handler));
	}

	void HciLayer::UnregisterLeEventHandler(SubeventCode subevent_code) {
	CallOn(impl_, &impl::handle_unregister_le_event_handler, subevent_code);
	}

	AclConnectionInterface* HciLayer::GetAclConnectionInterface(common::Callback<void(EventPacketView)> event_handler,
	common::Callback<void(uint16_t, ErrorCode)> on_disconnect,
	os::Handler* handler) {
	for (const auto event : AclConnectionEvents) {
	RegisterEventHandler(event, event_handler, handler);
	}
	return &impl_->acl_connection_manager_interface_;
	}

	LeAclConnectionInterface* HciLayer::GetLeAclConnectionInterface(
	common::Callback<void(LeMetaEventView)> event_handler, common::Callback<void(uint16_t, ErrorCode)> on_disconnect,
	os::Handler* handler) {
	for (const auto event : LeConnectionManagementEvents) {
	RegisterLeEventHandler(event, event_handler, handler);
	}
	return &impl_->le_acl_connection_manager_interface_;
	}

	SecurityInterface* HciLayer::GetSecurityInterface(common::Callback<void(EventPacketView)> event_handler,
	os::Handler* handler) {
	for (const auto event : SecurityEvents) {
	RegisterEventHandler(event, event_handler, handler);
	}
	return &impl_->security_interface;
	}

	LeSecurityInterface* HciLayer::GetLeSecurityInterface(common::Callback<void(LeMetaEventView)> event_handler,
	os::Handler* handler) {
	for (const auto subevent : LeSecurityEvents) {
	RegisterLeEventHandler(subevent, event_handler, handler);
	}
	return &impl_->le_security_interface;
	}

	LeAdvertisingInterface* HciLayer::GetLeAdvertisingInterface(common::Callback<void(LeMetaEventView)> event_handler,
	os::Handler* handler) {
	for (const auto subevent : LeAdvertisingEvents) {
	RegisterLeEventHandler(subevent, event_handler, handler);
	}
	return &impl_->le_advertising_interface;
	}

	LeScanningInterface* HciLayer::GetLeScanningInterface(common::Callback<void(LeMetaEventView)> event_handler,
	os::Handler* handler) {
	for (const auto subevent : LeScanningEvents) {
	RegisterLeEventHandler(subevent, event_handler, handler);
	}
	return &impl_->le_scanning_interface;
	}

	const ModuleFactory HciLayer::Factory = ModuleFactory([]() { return new HciLayer(); });

	void HciLayer::ListDependencies(ModuleList* list) {
	list->add<hal::HciHal>();
	}

	void HciLayer::Start() {
	auto hal = GetDependency<hal::HciHal>();
	impl_->Start(hal);
	hal->registerIncomingPacketCallback(hal_callbacks_);
	}

	void HciLayer::Stop() {
	auto hal = GetDependency<hal::HciHal>();
	hal->unregisterIncomingPacketCallback();
	impl_->Stop();
	}

	} // namespace hci
	} // namespace bluetooth