/* Copyright (c) 2012 - 2021 Advanced Micro Devices, Inc.

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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 THE SOFTWARE. */

#include "commandqueue.hpp"
#include "thread/monitor.hpp"
#include "device/device.hpp"
#include "platform/context.hpp"

/*!
 * \file commandQueue.cpp
 * \brief  Definitions for HostQueue object.
 *
 * \author Laurent Morichetti
 * \date   October 2008
 */

namespace amd {

HostQueue::HostQueue(Context& context, Device& device, cl_command_queue_properties properties,
                     uint queueRTCUs, Priority priority, const std::vector<uint32_t>& cuMask)
    : CommandQueue(context, device, properties, device.info().queueProperties_, queueRTCUs,
                   priority, cuMask),
      lastEnqueueCommand_(nullptr),
      head_(nullptr),
      tail_(nullptr),
      isActive_(false) {
  if (AMD_DIRECT_DISPATCH) {
    // Initialize the queue
    thread_.Init(this);
  } else {
    if (thread_.state() >= Thread::INITIALIZED) {
      ScopedLock sl(queueLock_);
      thread_.start(this);
      queueLock_.wait();
    }
  }
}

bool HostQueue::terminate() {
  if (AMD_DIRECT_DISPATCH) {
    Command* marker = new Marker(*this, true);
    if (marker != nullptr) {
      marker->enqueue();
      marker->awaitCompletion();
      marker->release();
    }
    thread_.acceptingCommands_ = false;
    thread_.Release();
  } else {
    if (Os::isThreadAlive(thread_)) {
      Command* marker = nullptr;

      // Send a finish if the queue is still accepting commands.
      {
        ScopedLock sl(queueLock_);
        if (thread_.acceptingCommands_) {
          marker = new Marker(*this, false);
          if (marker != nullptr) {
            append(*marker);
            queueLock_.notify();
          }
        }
      }
      if (marker != nullptr) {
        marker->awaitCompletion();
        marker->release();
      }

      // Wake-up the command loop, so it can exit
      {
        ScopedLock sl(queueLock_);
        thread_.acceptingCommands_ = false;
        queueLock_.notify();
      }

      // FIXME_lmoriche: fix termination handshake
      while (thread_.state() < Thread::FINISHED) {
        Os::yield();
      }
    }
  }

  if (Agent::shouldPostCommandQueueEvents()) {
    Agent::postCommandQueueFree(as_cl(this->asCommandQueue()));
  }

  return true;
}

void HostQueue::finish() {
  Command* command = nullptr;
  if (IS_HIP) {
    command = getLastQueuedCommand(true);
    // Check if the queue has nothing to process and return
    if (AMD_DIRECT_DISPATCH &&  command == nullptr) {
      return;
    }
  }
  if (nullptr == command) {
    // Send a finish to make sure we finished all commands
    command = new Marker(*this, false);
    if (command == NULL) {
      return;
    }
    ClPrint(LOG_DEBUG, LOG_CMD, "marker is queued");
    command->enqueue();
  }
  // Check HW status of the ROCcrl event. Note: not all ROCclr modes support HW status
  static constexpr bool kWaitCompletion = true;
  if (!device().IsHwEventReady(command->event(), kWaitCompletion)) {
    ClPrint(LOG_DEBUG, LOG_CMD, "HW Event not ready, awaiting completion instead");
    command->awaitCompletion();
  }
  command->release();
  if (IS_HIP) {
    ScopedLock sl(vdev()->execution());
    ScopedLock l(lastCmdLock_);
    if (lastEnqueueCommand_ != nullptr) {
      lastEnqueueCommand_->release();
      lastEnqueueCommand_ = nullptr;
    }
  }
  ClPrint(LOG_DEBUG, LOG_CMD, "All commands finished");
}

void HostQueue::loop(device::VirtualDevice* virtualDevice) {
  // Notify the caller that the queue is ready to accept commands.
  {
    ScopedLock sl(queueLock_);
    thread_.acceptingCommands_ = true;
    queueLock_.notify();
  }
  // Create a command batch with all the commands present in the queue.
  Command* head = NULL;
  Command* tail = NULL;
  while (true) {
    // Get one command from the queue
    Command* command = queue_.dequeue();
    if (command == NULL) {
      ScopedLock sl(queueLock_);
      while ((command = queue_.dequeue()) == NULL) {
        if (!thread_.acceptingCommands_) {
          return;
        }
        queueLock_.wait();
      }
    }

    command->retain();

    // Process the command's event wait list.
    const Command::EventWaitList& events = command->eventWaitList();
    bool dependencyFailed = false;

    for (const auto& it : events) {
      // Only wait if the command is enqueued into another queue.
      if (it->command().queue() != this) {
        // Runtime has to flush the current batch only if the dependent wait is blocking
        if (it->command().status() != CL_COMPLETE) {
          virtualDevice->flush(head, true);
          tail = head = NULL;
          dependencyFailed |= !it->awaitCompletion();
        }
      }
    }

    // Insert the command to the linked list.
    if (NULL == head) {  // if the list is empty
      head = tail = command;
    } else {
      tail->setNext(command);
      tail = command;
    }

    if (dependencyFailed) {
      command->setStatus(CL_EXEC_STATUS_ERROR_FOR_EVENTS_IN_WAIT_LIST);
      continue;
    }

    ClPrint(LOG_DEBUG, LOG_CMD, "command (%s) is submitted: %p", getOclCommandKindString(command->type()), command);

    command->setStatus(CL_SUBMITTED);

    // Submit to the device queue.
    command->submit(*virtualDevice);

    // if this is a user invisible marker command, then flush
    if (0 == command->type()) {
      virtualDevice->flush(head);
      tail = head = NULL;
    }
  }  // while (true) {
}

void HostQueue::append(Command& command) {
  // We retain the command here. It will be released when its status
  // changes to CL_COMPLETE
  if ((command.getWaitBits() & 0x1) != 0) {
    finish();
  }
  command.retain();
  command.setStatus(CL_QUEUED);
  queue_.enqueue(&command);
  if (!IS_HIP) {
    return;
  }

  // Set last submitted command
  Command* prevLastEnqueueCommand;
  command.retain();
  {
    // lastCmdLock_ ensures that lastEnqueueCommand() can retain the command before it is swapped
    // out. We want to keep this critical section as short as possible, so the command should be
    // released outside this section.
    ScopedLock l(lastCmdLock_);

    prevLastEnqueueCommand = lastEnqueueCommand_;
    lastEnqueueCommand_ = &command;
  }

  if (prevLastEnqueueCommand != nullptr) {
    prevLastEnqueueCommand->release();
  }
}

bool HostQueue::isEmpty() {
  // Get a snapshot of queue size
  return queue_.empty();
}

Command* HostQueue::getLastQueuedCommand(bool retain) {
  if (AMD_DIRECT_DISPATCH) {
    // The batch update must be lock protected to avoid a race condition
    // when multiple threads submit/flush/update the batch at the same time
    ScopedLock sl(vdev()->execution());
    // Since the lastCmdLock_ is acquired, it is safe to read and retain the lastEnqueueCommand.
    // It is guaranteed that the pointer will not change.
    if (retain && lastEnqueueCommand_ != nullptr) {
      lastEnqueueCommand_->retain();
    }
    return lastEnqueueCommand_;
  } else {
    // Get last submitted command
    ScopedLock l(lastCmdLock_);

    // Since the lastCmdLock_ is acquired, it is safe to read and retain the lastEnqueueCommand.
    // It is guaranteed that the pointer will not change.
    if (retain && lastEnqueueCommand_ != nullptr) {
      lastEnqueueCommand_->retain();
    }
    return lastEnqueueCommand_;
  }
}

DeviceQueue::~DeviceQueue() {
  delete virtualDevice_;
  ScopedLock lock(context().lock());
  context().removeDeviceQueue(device(), this);
}

bool DeviceQueue::create() {
  const bool defaultDeviceQueue = properties().test(CL_QUEUE_ON_DEVICE_DEFAULT);
  bool result = false;

  virtualDevice_ = device().createVirtualDevice(this);
  if (virtualDevice_ != NULL) {
    result = true;
    context().addDeviceQueue(device(), this, defaultDeviceQueue);
  }

  return result;
}

}  // namespace amd