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// Copyright 2019 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.
#pragma once
#include <ddk/device.h>
#include <fbl/array.h>
#include <fbl/auto_lock.h>
#include <fbl/mutex.h>
#include <fbl/ref_counted.h>
#include <fbl/string.h>
#include <fuchsia/device/c/fidl.h>
#include <fuchsia/device/manager/c/fidl.h>
#include <lib/async/cpp/task.h>
#include <lib/async/cpp/wait.h>
#include <lib/zx/channel.h>
#include <lib/zx/event.h>
#include <variant>
#include "composite-device.h"
#include "metadata.h"
#include "../shared/async-loop-ref-counted-rpc-handler.h"
namespace devmgr {
class Coordinator;
class Devhost;
struct Devnode;
class SuspendContext;
class SuspendTask;
// clang-format off
// This device is never destroyed
#define DEV_CTX_IMMORTAL 0x01
// This device requires that children are created in a
// new devhost attached to a proxy device
// This device may be bound multiple times
#define DEV_CTX_MULTI_BIND 0x04
// This device is bound and not eligible for binding
// again until unbound. Not allowed on MULTI_BIND ctx.
#define DEV_CTX_BOUND 0x08
// Device has been remove()'d
#define DEV_CTX_DEAD 0x10
// Device is a proxy -- its "parent" is the device it's
// a proxy to.
#define DEV_CTX_PROXY 0x40
// Device is not visible in devfs or bindable.
// Devices may be created in this state, but may not
// return to this state once made visible.
#define DEV_CTX_INVISIBLE 0x80
// Signals used on the test event
// clang-format on
struct Device : public fbl::RefCounted<Device>, public AsyncLoopRefCountedRpcHandler<Device> {
// Node for entry in device child list
struct Node {
static fbl::DoublyLinkedListNodeState<Device*>& node_state(Device& obj) {
return obj.node_;
struct DevhostNode {
static fbl::DoublyLinkedListNodeState<Device*>& node_state(Device& obj) {
return obj.devhost_node_;
struct AllDevicesNode {
static fbl::DoublyLinkedListNodeState<Device*>& node_state(Device& obj) {
return obj.all_devices_node_;
// This iterator provides access to a list of devices that does not provide
// mechanisms for mutating that list. With this, a user can get mutable
// access to a device in the list. This is achieved by making the linked
// list iterator opaque. It is not safe to modify the underlying list while
// this iterator is in use.
template <typename IterType, typename DeviceType>
class ChildListIterator {
ChildListIterator() : state_(Done{}) {}
explicit ChildListIterator(DeviceType* device)
: state_(device->children_.begin()), device_(device) {
ChildListIterator operator++(int) {
auto other = *this;
return other;
bool operator==(const ChildListIterator& other) const { return state_ == other.state_; }
bool operator!=(const ChildListIterator& other) const { return !(state_ == other.state_); }
// The iterator implementation for the child list. This is the source of truth
// for what devices are children of the device.
ChildListIterator& operator++() {
std::visit([this](auto&& arg) {
using T = std::decay_t<decltype(arg)>;
if constexpr (std::is_same_v<T, IterType>) {
} else if constexpr (std::is_same_v<T, Composite>) {
state_ = Done{};
} else if constexpr (std::is_same_v<T, Done>) {
state_ = Done{};
}, state_);
return *this;
DeviceType& operator*() const {
return std::visit([this](auto&& arg) -> DeviceType& {
using T = std::decay_t<decltype(arg)>;
if constexpr (std::is_same_v<T, IterType>) {
return *arg;
} else if constexpr (std::is_same_v<T, Composite>) {
return *device_->parent_->component()->composite()->device();
} else {
}, state_);
// Advance the iterator to the next valid state or reach the done state.
// This is used to handle advancement between the different state variants.
void SkipInvalidStates() {
bool more = true;
while (more) {
more = std::visit([this](auto&& arg) {
using T = std::decay_t<decltype(arg)>;
if constexpr (std::is_same_v<T, IterType>) {
// Check if there are any more children in the list. If
// there are, we're in a valid state and can stop.
// Otherwise, advance to the next variant and check if
// it's a valid state.
if (arg != device_->children_.end()) {
return false;
state_ = Composite{};
return true;
} else if constexpr (std::is_same_v<T, Composite>) {
// Check if this device is an internal component device
// that bound to a composite component. If it is, and
// the composite has been constructed, the iterator
// should yield the composite.
CompositeDeviceComponent* component = nullptr;
if (device_->parent_) {
component = device_->parent_->component();
if (component != nullptr && component->composite()->device() != nullptr) {
return false;
state_ = Done{};
return false;
} else if constexpr (std::is_same_v<T, Done>) {
return false;
}, state_);
struct Composite {
bool operator==(Composite) const { return true; }
struct Done {
bool operator==(Done) const { return true; }
std::variant<IterType, Composite, Done> state_;
DeviceType* device_;
// This class exists to allow consumers of the Device class to write
// for (auto& child : dev->children())
// and get mutable access to the children without getting mutable access to
// the list.
template <typename DeviceType, typename IterType>
class ChildListIteratorFactory {
explicit ChildListIteratorFactory(DeviceType* device) : device_(device) {}
IterType begin() const { return IterType(device_); }
IterType end() const { return IterType(); }
bool is_empty() const { return begin() == end(); }
DeviceType* device_;
Device(Coordinator* coord, fbl::String name, fbl::String libname, fbl::String args,
fbl::RefPtr<Device> parent, uint32_t protocol_id, zx::channel client_remote);
// Create a new device with the given parameters. This sets up its
// relationship with its parent and devhost and adds its RPC channel to the
// coordinator's async loop. This does not add the device to the
// coordinator's devices_ list, or trigger publishing
static zx_status_t Create(Coordinator* coordinator, const fbl::RefPtr<Device>& parent,
fbl::String name, fbl::String driver_path, fbl::String args,
uint32_t protocol_id, fbl::Array<zx_device_prop_t> props,
zx::channel rpc, bool invisible, zx::channel client_remote,
fbl::RefPtr<Device>* device);
static zx_status_t CreateComposite(Coordinator* coordinator, Devhost* devhost,
const CompositeDevice& composite, zx::channel rpc,
fbl::RefPtr<Device>* device);
zx_status_t CreateProxy();
static void HandleRpc(fbl::RefPtr<Device>&& dev, async_dispatcher_t* dispatcher,
async::WaitBase* wait, zx_status_t status,
const zx_packet_signal_t* signal);
// We do not want to expose the list itself for mutation, even if the
// children are allowed to be mutated. We manage this by making the
// iterator opaque.
using NonConstChildListIterator =
ChildListIterator<fbl::DoublyLinkedList<Device*, Node>::iterator, Device>;
using ConstChildListIterator =
ChildListIterator<fbl::DoublyLinkedList<Device*, Node>::const_iterator, const Device>;
using NonConstChildListIteratorFactory =
ChildListIteratorFactory<Device, NonConstChildListIterator>;
using ConstChildListIteratorFactory =
ChildListIteratorFactory<const Device, ConstChildListIterator>;
NonConstChildListIteratorFactory children() {
return NonConstChildListIteratorFactory(this);
ConstChildListIteratorFactory children() const {
return ConstChildListIteratorFactory(this);
// Signal that this device is ready for bind to happen. This should happen
// either immediately after the device is created, if it's created visible,
// or after it becomes visible.
zx_status_t SignalReadyForBind(zx::duration delay = zx::sec(0));
using SuspendCompletion = fit::function<void(zx_status_t)>;
// Issue a Suspend request to this device. When the response comes in, the
// given completion will be invoked.
zx_status_t SendSuspend(uint32_t flags, SuspendCompletion completion);
// Break the relationship between this device object and its parent
void DetachFromParent();
// Sets the properties of this device. Returns an error if the properties
// array contains more than one property from the BIND_TOPO_* range.
zx_status_t SetProps(fbl::Array<const zx_device_prop_t> props);
const fbl::Array<const zx_device_prop_t>& props() const { return props_; }
const zx_device_prop_t* topo_prop() const { return topo_prop_; }
const fbl::RefPtr<Device>& parent() { return parent_; }
fbl::RefPtr<const Device> parent() const { return parent_; }
const fbl::RefPtr<Device>& proxy() { return proxy_; }
fbl::RefPtr<const Device> proxy() const { return proxy_; }
uint32_t protocol_id() const { return protocol_id_; }
bool is_bindable() const {
// If the device was bound as a component of a composite, this returns the
// component's description.
CompositeDeviceComponent* component() const {
auto val = std::get_if<CompositeDeviceComponent*>(&composite_);
return val ? *val : nullptr;
void set_component(CompositeDeviceComponent* component) {
composite_ = component;
// If the device was created as a composite, this returns its description.
CompositeDevice* composite() const {
auto val = std::get_if<CompositeDevice*>(&composite_);
return val ? *val : nullptr;
void set_composite(CompositeDevice* composite) {
composite_ = composite;
void disassociate_from_composite() {
composite_ = UnassociatedWithComposite{};
void set_host(Devhost* host);
Devhost* host() const { return host_; }
uint64_t local_id() const { return local_id_; }
const fbl::DoublyLinkedList<fbl::unique_ptr<Metadata>, Metadata::Node>& metadata() const {
return metadata_;
void AddMetadata(fbl::unique_ptr<Metadata> md) {
// Creates a new suspend task if necessary and returns a reference to it.
// If one is already in-progress, a reference to it is returned instead
fbl::RefPtr<SuspendTask> RequestSuspendTask(uint32_t suspend_flags);
// Run the completion for the outstanding suspend, if any. This method is
// only exposed currently because RemoveDevice is on Coordinator instead of
// Device.
void CompleteSuspend(zx_status_t status);
zx_status_t DriverCompatibiltyTest(const char* drivername);
zx::channel take_client_remote() { return std::move(client_remote_); }
const fbl::String& name() const { return name_; }
const fbl::String& libname() const { return libname_; }
const fbl::String& args() const { return args_; }
Coordinator* coordinator;
uint32_t flags = 0;
// The backoff between each driver retry. This grows exponentially.
zx::duration backoff = zx::msec(250);
// The number of retries left for the driver.
uint32_t retries = 4;
Devnode* self = nullptr;
Devnode* link = nullptr;
// TODO(teisenbe): We probably want more states. For example, the DEAD flag
// should probably move in to here.
enum class State {
State state() const { return state_; }
enum class TestStateMachine {
kTestNotStarted = 1,
TestStateMachine test_state() {
fbl::AutoLock<fbl::Mutex> lock(&test_state_lock_);
return test_state_;
void set_test_state(TestStateMachine new_state) {
fbl::AutoLock<fbl::Mutex> lock(&test_state_lock_);
test_state_ = new_state;
zx::event& test_event() { return test_event_; }
const char* test_driver_name() {return test_driver_name_; }
void set_test_driver_name(const char* drivername) {
strncpy(test_driver_name_, drivername, sizeof(test_driver_name_) - 1);
zx_status_t HandleRead();
int RunCompatibilityTests();
const fbl::String name_;
const fbl::String libname_;
const fbl::String args_;
fbl::RefPtr<Device> parent_;
const uint32_t protocol_id_;
fbl::RefPtr<Device> proxy_;
fbl::Array<const zx_device_prop_t> props_;
// If the device has a topological property in |props|, this points to it.
const zx_device_prop_t* topo_prop_ = nullptr;
async::TaskClosure publish_task_;
// listnode for this device in its parent's list-of-children
fbl::DoublyLinkedListNodeState<Device*> node_;
// List of all child devices of this device, except for composite devices.
// Composite devices are excluded because their multiple-parent nature
// precludes using the same intrusive nodes as single-parent devices.
fbl::DoublyLinkedList<Device*, Node> children_;
// Metadata entries associated to this device.
fbl::DoublyLinkedList<fbl::unique_ptr<Metadata>, Metadata::Node> metadata_;
// listnode for this device in the all devices list
fbl::DoublyLinkedListNodeState<Device*> all_devices_node_;
// listnode for this device in its devhost's list-of-devices
fbl::DoublyLinkedListNodeState<Device*> devhost_node_;
// - If this device is part of a composite device, this is inhabited by
// CompositeDeviceComponent* and it points to the component that matched it.
// Note that this is only set on the device that matched the component, not
// the "component device" added by the component driver.
// - If this device is a composite device, this is inhabited by
// CompositeDevice* and it points to the composite that describes it.
// - Otherwise, it is inhabited by UnassociatedWithComposite
struct UnassociatedWithComposite {};
std::variant<UnassociatedWithComposite, CompositeDeviceComponent*, CompositeDevice*>
Devhost* host_ = nullptr;
// The id of this device from the perspective of the devhost. This can be
// used to communicate with the devhost about this device.
uint64_t local_id_ = 0;
// The current state of the device
State state_ = State::kActive;
// If a suspend is in-progress, this task represents it.
fbl::RefPtr<SuspendTask> active_suspend_;
// If a suspend is in-progress, this completion will be invoked when it is
// completed. It will likely mark |active_suspend_| as completed and clear
// it.
SuspendCompletion suspend_completion_;
// For attaching as an open connection to the proxy device,
// or once the device becomes visible.
zx::channel client_remote_;
fbl::Mutex test_state_lock_;
TestStateMachine test_state_ = TestStateMachine::kTestNotStarted;
zx::event test_event_;
char test_driver_name_[fuchsia_device_MAX_DRIVER_NAME_LEN + 1] = {0};
} // namespace devmgr