zircon/system/core/devmgr/devhost/zx-device.h

// Copyright 2016 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 <atomic>
#include <ddk/device.h>
#include <fbl/intrusive_double_list.h>
#include <fbl/intrusive_wavl_tree.h>
#include <fbl/mutex.h>
#include <fbl/recycler.h>
#include <fbl/ref_counted_upgradeable.h>
#include <fbl/ref_ptr.h>
#include <fbl/vector.h>
#include <fs/handler.h>
#include <lib/zx/channel.h>
#include <lib/zx/eventpair.h>
#include <zircon/compiler.h>
#include <zircon/thread_annotations.h>

namespace devmgr {

class CompositeDevice;
class DeviceControllerConnection;
struct ProxyIostate;

} // namespace devmgr

#define DEV_MAGIC 'MDEV'

// This needs to be a struct, not a class, to match the public definition
struct zx_device : fbl::RefCountedUpgradeable<zx_device>, fbl::Recyclable<zx_device> {
    ~zx_device() = default;

    zx_device(const zx_device&) = delete;
    zx_device& operator=(const zx_device&) = delete;

    static zx_status_t Create(fbl::RefPtr<zx_device>* out_dev);

    zx_status_t OpenOp(zx_device_t** dev_out, uint32_t flags) {
        return Dispatch(ops->open, ZX_OK, dev_out, flags);
    }

    zx_status_t CloseOp(uint32_t flags) {
        return Dispatch(ops->close, ZX_OK, flags);
    }

    void UnbindOp() {
        Dispatch(ops->unbind);
    }

    void ReleaseOp() {
        Dispatch(ops->release);
    }

    zx_status_t SuspendOp(uint32_t flags) {
        return Dispatch(ops->suspend, ZX_ERR_NOT_SUPPORTED, flags);
    }

    zx_status_t ResumeOp(uint32_t flags) {
        return Dispatch(ops->resume, ZX_ERR_NOT_SUPPORTED, flags);
    }

    zx_status_t ReadOp(void* buf, size_t count, zx_off_t off, size_t* actual) {
        return Dispatch(ops->read, ZX_ERR_NOT_SUPPORTED, buf, count, off, actual);
    }

    zx_status_t WriteOp(const void* buf, size_t count, zx_off_t off, size_t* actual) {
        return Dispatch(ops->write, ZX_ERR_NOT_SUPPORTED, buf, count, off, actual);
    }

    zx_off_t GetSizeOp() {
        return Dispatch(ops->get_size, 0lu);
    }

    zx_status_t IoctlOp(uint32_t op, const void* in_buf, size_t in_len, void* out_buf,
                        size_t out_len, size_t* out_actual) {
        return Dispatch(ops->ioctl, ZX_ERR_NOT_SUPPORTED, op, in_buf, in_len, out_buf, out_len, out_actual);
    }

    zx_status_t MessageOp(fidl_msg_t* msg, fidl_txn_t* txn) {
      return Dispatch(ops->message, ZX_ERR_NOT_SUPPORTED, msg, txn);
    }

    void PushBindConn(const fs::FidlConnection& conn);
    bool PopBindConn(fs::FidlConnection* conn);

    // Check if this devhost has a device with the given ID, and if so returns a
    // reference to it.
    static fbl::RefPtr<zx_device> GetDeviceFromLocalId(uint64_t local_id);

    uint64_t local_id() const { return local_id_; }
    void set_local_id(uint64_t id);

    uintptr_t magic = DEV_MAGIC;

    const zx_protocol_device_t* ops = nullptr;

    // reserved for driver use; will not be touched by devmgr
    void* ctx = nullptr;

    uint32_t flags = 0;

    zx::eventpair event;
    zx::eventpair local_event;
    // The RPC channel is owned by |conn|
    zx::unowned_channel rpc;

    // most devices implement a single
    // protocol beyond the base device protocol
    uint32_t protocol_id = 0;
    void* protocol_ops = nullptr;

    // driver that has published this device
    zx_driver_t* driver = nullptr;

    // parent in the device tree
    fbl::RefPtr<zx_device_t> parent;

    // for the parent's device_list
    fbl::DoublyLinkedListNodeState<zx_device*> node;
    struct Node {
        static fbl::DoublyLinkedListNodeState<zx_device*>& node_state(zx_device& obj) {
            return obj.node;
        }
    };

    // list of this device's children in the device tree
    fbl::DoublyLinkedList<zx_device*, Node> children;

    // list node for the defer_device_list
    fbl::DoublyLinkedListNodeState<zx_device*> defer;
    struct DeferNode {
        static fbl::DoublyLinkedListNodeState<zx_device*>& node_state(zx_device& obj) {
            return obj.defer;
        }
    };

    // This is an atomic so that the connection's async loop can inspect this
    // value to determine if an expected shutdown is happening.  See comments in
    // devhost_remove().
    std::atomic<devmgr::DeviceControllerConnection*> conn = nullptr;

    fbl::Mutex proxy_ios_lock;
    devmgr::ProxyIostate* proxy_ios TA_GUARDED(proxy_ios_lock) = nullptr;

    char name[ZX_DEVICE_NAME_MAX + 1] = {};

    // Trait structures for the local ID map
    struct LocalIdNode {
        static fbl::WAVLTreeNodeState<fbl::RefPtr<zx_device>>& node_state(zx_device& obj) {
            return obj.local_id_node_;
        }
    };
    struct LocalIdKeyTraits {
        static uint64_t GetKey(const zx_device& obj) { return obj.local_id_; }
        static bool LessThan(const uint64_t& key1, const uint64_t& key2)  { return key1 <  key2; }
        static bool EqualTo (const uint64_t& key1, const uint64_t& key2)  { return key1 == key2; }
    };

    void set_composite(fbl::RefPtr<devmgr::CompositeDevice> composite);
    fbl::RefPtr<devmgr::CompositeDevice> take_composite();

private:
    zx_device() = default;

    friend class fbl::Recyclable<zx_device_t>;
    void fbl_recycle();

    // Templates that dispatch the protocol operations if they were set.
    // If they were not set, the second paramater is returned to the caller
    // (usually ZX_ERR_NOT_SUPPORTED)
    template <typename RetType, typename... ArgTypes>
    RetType Dispatch(RetType (*op)(void* ctx, ArgTypes...),
                     RetType fallback, ArgTypes... args) {
        return op ? (*op)(ctx, args...) : fallback;
    }

    template <typename... ArgTypes>
    void Dispatch(void (*op)(void* ctx, ArgTypes...), ArgTypes... args) {
        if (op) {
            (*op)(ctx, args...);
        }
    }

    // If this device is a component of a composite, this points to the
    // composite control structure.
    fbl::RefPtr<devmgr::CompositeDevice> composite_;

    fbl::WAVLTreeNodeState<fbl::RefPtr<zx_device>> local_id_node_;

    // Identifier assigned by devmgr that can be used to assemble composite
    // devices.
    uint64_t local_id_ = 0;

    // The connection associated with a fuchsia.device.Controller/Bind.
    fbl::Mutex bind_conn_lock_;
    fbl::Vector<fs::FidlConnection> bind_conn_ TA_GUARDED(bind_conn_lock_);
};

// zx_device_t objects must be created or initialized by the driver manager's
// device_create() function.  Drivers MAY NOT touch any
// fields in the zx_device_t, except for the protocol_id and protocol_ops
// fields which it may fill out after init and before device_add() is called,
// and the ctx field which may be used to store driver-specific data.

// clang-format off

#define DEV_FLAG_DEAD           0x00000001  // being deleted
#define DEV_FLAG_VERY_DEAD      0x00000002  // safe for ref0 and release()
#define DEV_FLAG_UNBINDABLE     0x00000004  // nobody may bind to this device
#define DEV_FLAG_BUSY           0x00000010  // device being created
#define DEV_FLAG_INSTANCE       0x00000020  // this device was created-on-open
#define DEV_FLAG_MULTI_BIND     0x00000080  // this device accepts many children
#define DEV_FLAG_ADDED          0x00000100  // device_add() has been called for this device
#define DEV_FLAG_INVISIBLE      0x00000200  // device not visible via devfs
#define DEV_FLAG_UNBOUND        0x00000400  // informed that it should self-delete asap
#define DEV_FLAG_WANTS_REBIND   0x00000800  // when last child goes, rebind this device

// clang-format on

zx_status_t device_bind(const fbl::RefPtr<zx_device_t>& dev, const char* drv_libname);
zx_status_t device_unbind(const fbl::RefPtr<zx_device_t>& dev);
zx_status_t device_open(const fbl::RefPtr<zx_device_t>& dev, fbl::RefPtr<zx_device_t>* out,
                        uint32_t flags);
// Note that device_close() is intended to consume a reference (logically, the
// one created by device_open).
zx_status_t device_close(fbl::RefPtr<zx_device_t> dev, uint32_t flags);