src/connectivity/bluetooth/core/bt-host/host_device.cc

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "host_device.h"

#include <zircon/status.h>

#include "host.h"
#include "src/connectivity/bluetooth/core/bt-host/common/log.h"
#include "src/connectivity/bluetooth/core/bt-host/hci/device_wrapper.h"

namespace bthost {

HostDevice::HostDevice(zx_device_t* device)
    : dev_(nullptr), parent_(device), loop_(&kAsyncLoopConfigNoAttachToThread) {
  ZX_DEBUG_ASSERT(parent_);

  dev_proto_.version = DEVICE_OPS_VERSION;
  dev_proto_.unbind = &HostDevice::DdkUnbind;
  dev_proto_.release = &HostDevice::DdkRelease;
  dev_proto_.message = &HostDevice::DdkMessage;
}

zx_status_t HostDevice::Bind() {
  bt_log(TRACE, "bt-host", "bind");

  std::lock_guard<std::mutex> lock(mtx_);

  bt_hci_protocol_t hci_proto;
  zx_status_t status =
      device_get_protocol(parent_, ZX_PROTOCOL_BT_HCI, &hci_proto);
  if (status != ZX_OK) {
    bt_log(ERROR, "bt-host", "failed to obtain bt-hci protocol ops: %s",
           zx_status_get_string(status));
    return status;
  }

  if (!hci_proto.ops) {
    bt_log(ERROR, "bt-host", "bt-hci device ops required!");
    return ZX_ERR_NOT_SUPPORTED;
  }

  if (!hci_proto.ops->open_command_channel) {
    bt_log(ERROR, "bt-host", "bt-hci op required: open_command_channel");
    return ZX_ERR_NOT_SUPPORTED;
  }

  if (!hci_proto.ops->open_acl_data_channel) {
    bt_log(ERROR, "bt-host", "bt-hci op required: open_acl_data_channel");
    return ZX_ERR_NOT_SUPPORTED;
  }

  if (!hci_proto.ops->open_snoop_channel) {
    bt_log(ERROR, "bt-host", "bt-hci op required: open_snoop_channel");
    return ZX_ERR_NOT_SUPPORTED;
  }

  // We are required to publish a device before returning from Bind but we
  // haven't fully initialized the adapter yet. We create the bt-host device as
  // invisible until initialization completes on the host thread. We also
  // disallow other drivers from directly binding to it.
  device_add_args_t args = {
      .version = DEVICE_ADD_ARGS_VERSION,
      .name = "bt_host",
      .ctx = this,
      .ops = &dev_proto_,
      .proto_id = ZX_PROTOCOL_BT_HOST,
      .flags = DEVICE_ADD_NON_BINDABLE | DEVICE_ADD_INVISIBLE,
  };

  status = device_add(parent_, &args, &dev_);
  if (status != ZX_OK) {
    bt_log(ERROR, "bt-host", "Failed to publish device: %s",
           zx_status_get_string(status));
    return status;
  }

  loop_.StartThread("bt-host (gap)");

  // Send the bootstrap message to Host. The Host object can only be accessed on
  // the Host thread.
  async::PostTask(loop_.dispatcher(), [hci_proto, this] {
    bt_log(SPEW, "bt-host", "host thread start");

    std::lock_guard<std::mutex> lock(mtx_);
    host_ = fxl::MakeRefCounted<Host>(hci_proto);
    host_->Initialize([host = host_, this](bool success) {
      {
        std::lock_guard<std::mutex> lock(mtx_);

        // Abort if CleanUp has been called.
        if (!host_)
          return;

        if (success) {
          bt_log(TRACE, "bt-host", "adapter initialized; make device visible");
          host_->gatt_host()->SetRemoteServiceWatcher(
              fit::bind_member(this, &HostDevice::OnRemoteGattServiceAdded));
          device_make_visible(dev_);
          return;
        }

        bt_log(ERROR, "bt-host", "failed to initialize adapter");
        CleanUp();
      }

      host->ShutDown();
      loop_.Shutdown();
    });
  });

  return ZX_OK;
}

void HostDevice::Unbind() {
  bt_log(TRACE, "bt-host", "unbind");

  std::lock_guard<std::mutex> lock(mtx_);

  if (!host_)
    return;

  // Do this immediately to stop receiving new service callbacks.
  host_->gatt_host()->SetRemoteServiceWatcher({});

  async::PostTask(loop_.dispatcher(), [this, host = host_] {
    host->ShutDown();
    loop_.Quit();
  });

  // Make sure that the ShutDown task runs before this returns.
  loop_.JoinThreads();

  CleanUp();
}

void HostDevice::Release() {
  bt_log(TRACE, "bt-host", "release");
  delete this;
}

zx_status_t HostDevice::OpenHostChannel(zx::channel channel) {
  ZX_DEBUG_ASSERT(channel);
  std::lock_guard<std::mutex> lock(mtx_);

  // It's possible that this is being processed whilst the device is unbinding,
  // in which case |host_| can be null
  if (!host_) {
    bt_log(ERROR, "bt-host", "Cannot open channel, host is unbound");
    return ZX_ERR_BAD_STATE;
  }

  // Tell Host to start processing messages on this handle.
  ZX_DEBUG_ASSERT(host_);
  async::PostTask(loop_.dispatcher(),
                  [host = host_, chan = std::move(channel)]() mutable {
                    host->BindHostInterface(std::move(chan));
                  });

  return ZX_OK;
}

void HostDevice::OnRemoteGattServiceAdded(
    bt::gatt::PeerId peer_id, fbl::RefPtr<bt::gatt::RemoteService> service) {
  auto gatt_device =
      std::make_unique<GattRemoteServiceDevice>(dev_, peer_id, service);
  auto gatt_device_ptr = gatt_device.get();

  zx_status_t status = gatt_device->Bind();
  if (status != ZX_OK)
    return;

  gatt_devices_[gatt_device_ptr] = std::move(gatt_device);

  service->AddRemovedHandler(
      [this, gatt_device_ptr] { gatt_devices_.erase(gatt_device_ptr); });
}

void HostDevice::CleanUp() {
  host_ = nullptr;

  // Removing the devices explicitly instead of letting unbind handle it for us.
  gatt_devices_.clear();
  device_remove(dev_);

  dev_ = nullptr;
}

}  // namespace bthost