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

// 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 "zx-device.h"

#include <fbl/auto_call.h>
#include <fbl/auto_lock.h>
#include <fbl/mutex.h>
#include "composite-device.h"
#include "devhost.h"

zx_status_t zx_device::Create(fbl::RefPtr<zx_device>* out_dev) {
    *out_dev = fbl::AdoptRef(new zx_device());
    return ZX_OK;
}

void zx_device::PushBindConn(const fs::FidlConnection& conn) {
    fbl::AutoLock<fbl::Mutex> lock(&bind_conn_lock_);
    bind_conn_.push_back(conn);
}

bool zx_device::PopBindConn(fs::FidlConnection* conn) {
    fbl::AutoLock<fbl::Mutex> lock(&bind_conn_lock_);
    if (bind_conn_.is_empty()) {
        return false;
    }
    *conn = bind_conn_[0];
    bind_conn_.erase(0);
    return true;
}

// We must disable thread-safety analysis due to not being able to statically
// guarantee the lock holding invariant.  Instead, we acquire the lock if
// it's not already being held by the current thread.
void zx_device::fbl_recycle() TA_NO_THREAD_SAFETY_ANALYSIS {
    bool acq_lock = !devmgr::DM_LOCK_HELD();
    if (acq_lock) {
        devmgr::DM_LOCK();
    }
    auto unlock = fbl::MakeAutoCall([acq_lock]() TA_NO_THREAD_SAFETY_ANALYSIS {
        if (acq_lock) {
            devmgr::DM_UNLOCK();
        }
    });

    if (this->flags & DEV_FLAG_INSTANCE) {
        // these don't get removed, so mark dead state here
        this->flags |= DEV_FLAG_DEAD | DEV_FLAG_VERY_DEAD;
    }
    if (this->flags & DEV_FLAG_BUSY) {
        // this can happen if creation fails
        // the caller to device_add() will free it
        printf("device: %p(%s): ref=0, busy, not releasing\n", this, this->name);
        return;
    }
#if TRACE_ADD_REMOVE
    printf("device: %p(%s): ref=0. releasing.\n", this, this->name);
#endif

    if (!(this->flags & DEV_FLAG_VERY_DEAD)) {
        printf("device: %p(%s): only mostly dead (this is bad)\n", this, this->name);
    }
    if (!this->children.is_empty()) {
        printf("device: %p(%s): still has children! not good.\n", this, this->name);
    }

    composite_.reset();
    this->event.reset();
    this->local_event.reset();

    // Put on the defered work list for finalization
    devmgr::defer_device_list.push_back(this);

    // Immediately finalize if there's not an active enumerator
    if (devmgr::devhost_enumerators == 0) {
        devmgr::devhost_finalize();
    }
}

static fbl::Mutex local_id_map_lock_;
static fbl::WAVLTree<uint64_t, fbl::RefPtr<zx_device>, zx_device::LocalIdKeyTraits,
        zx_device::LocalIdNode> local_id_map_ TA_GUARDED(local_id_map_lock_);

void zx_device::set_local_id(uint64_t id) {
    // If this is the last reference, we want it to go away outside of the lock
    fbl::RefPtr<zx_device> old_entry;

    fbl::AutoLock guard(&local_id_map_lock_);
    if (local_id_ != 0) {
        old_entry = local_id_map_.erase(*this);
        ZX_ASSERT(old_entry.get() == this);
    }

    local_id_ = id;
    if (id != 0) {
        local_id_map_.insert(fbl::WrapRefPtr(this));
    }
}

fbl::RefPtr<zx_device> zx_device::GetDeviceFromLocalId(uint64_t local_id) {
    fbl::AutoLock guard(&local_id_map_lock_);
    auto itr = local_id_map_.find(local_id);
    if (itr == local_id_map_.end()) {
        return nullptr;
    }
    return fbl::WrapRefPtr(&*itr);
}

fbl::RefPtr<devmgr::CompositeDevice> zx_device::take_composite() {
    return std::move(composite_);
}

void zx_device::set_composite(fbl::RefPtr<devmgr::CompositeDevice> composite) {
    composite_ = std::move(composite);
}