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/*
* Copyright (c) 2011-2013 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.
*
* Copyright (c) 2015 The University of Bologna
* All rights reserved.
*
* 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,
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @file
* HMCController declaration
*/
#ifndef __MEM_HMC_CONTROLLER_HH__
#define __MEM_HMC_CONTROLLER_HH__
#include "mem/noncoherent_xbar.hh"
#include "mem/port.hh"
#include "params/HMCController.hh"
/**
* HMC Controller, in general, is responsible for translating the host
* protocol (AXI for example) to serial links protocol. Plus, it should have
* large internal buffers to hide the access latency of the cube. It is also
* inferred from the standard [1] and the literature [2] that serial links
* share the same address range and packets can travel over any of them, so a
* load distribution mechanism is required.
* This model simply queues the incoming transactions (using a Bridge) and
* schedules them to the serial links using a simple round robin mechanism to
* balance the load among them. More advanced global scheduling policies and
* reordering and steering of transactions can be added to this model if
* required [3].
* [1] http://www.hybridmemorycube.org/specification-download/
* [2] Low-Power Hybrid Memory Cubes With Link Power Manageme and Two-Level
* Prefetching (J. Ahn et. al)
* [3] The Open-Silicon HMC Controller IP
* http://www.open-silicon.com/open-silicon-ips/hmc/
*/
class HMCController : public NoncoherentXBar
{
public:
HMCController(const HMCControllerParams &p);
private:
// Receive range change only on one of the ports (because they all have
// the same range)
virtual void recvRangeChange(PortID mem_side_port_id);
// Receive a request and distribute it among response ports
// Simply forwards the packet to the next serial link based on a
// Round-robin counter
virtual bool recvTimingReq(PacketPtr pkt, PortID cpu_side_port_id);
int numMemSidePorts;
// The round-robin counter
int rr_counter;
/**
* Function for rotating the round robin counter
* @return the next value of the counter
*/
int rotate_counter();
};
#endif //__MEM_HMC_CONTROLLER_HH__