src/mem/qos/turnaround_policy_ideal.hh

/*
 * Copyright (c) 2018 ARM Limited
 * All rights reserved
 *
 * The license below extends only to copyright in the software and shall
 * not be construed as granting a license to any other intellectual
 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
 * licensed hereunder.  You may use the software subject to the license
 * terms below provided that you ensure that this notice is replicated
 * unmodified and in its entirety in all distributions of the software,
 * modified or unmodified, in source code or in binary form.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef __MEM_QOS_TURNAROUND_POLICY_IDEAL_HH_
#define __MEM_QOS_TURNAROUND_POLICY_IDEAL_HH_

#include "base/compiler.hh"
#include "mem/qos/turnaround_policy.hh"

namespace gem5
{

namespace memory
{

namespace qos
{

/**
 * Ideal QoS Bus Turnaround policy
 *
 * Selects bus state based purely on highest QoS priority
 * queue with at least one packet. Tie breaks across read
 * and write queues are resolved by selecting current bus
 * state.
 */
class TurnaroundPolicyIdeal: public TurnaroundPolicy
{
  public:
    TurnaroundPolicyIdeal(const Params &);

    virtual ~TurnaroundPolicyIdeal();

    /**
     * Bus Selection function.
     *
     * @return selected bus state
     */
    virtual MemCtrl::BusState selectBusState() override;
};

} // namespace qos
} // namespace memory
} // namespace gem5

#endif /* __MEM_QOS_TURNAROUND_POLICY_IDEAL_HH_ */