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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) 2006 The Regents of The University of Michigan
+ * 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,
+ * 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.
+ *
+ * Authors: Ali Saidi
+ * Steve Reinhardt
+ * Andreas Hansson
+ * Erfan Azarkhish
+ */
+
+/**
+ * @file
+ * Declaration of the SerialLink Class, modeling Hybrid-Memory-Cube's serial
+ * interface.
+ */
+
+#ifndef __MEM_SERIAL_LINK_HH__
+#define __MEM_SERIAL_LINK_HH__
+
+#include <deque>
+
+#include "base/types.hh"
+#include "mem/mem_object.hh"
+#include "params/SerialLink.hh"
+
+/**
+ * SerialLink is a simple variation of the Bridge class, with the ability to
+ * account for the latency of packet serialization. We assume that the
+ * serializer component at the transmitter side does not need to receive the
+ * whole packet to start the serialization. But the deserializer waits for the
+ * complete packet to check its integrity first.
+ */
+class SerialLink : public MemObject
+{
+ protected:
+
+ /**
+ * A deferred packet stores a packet along with its scheduled
+ * transmission time
+ */
+ class DeferredPacket
+ {
+
+ public:
+
+ const Tick tick;
+ const PacketPtr pkt;
+
+ DeferredPacket(PacketPtr _pkt, Tick _tick) : tick(_tick), pkt(_pkt)
+ { }
+ };
+
+ // Forward declaration to allow the slave port to have a pointer
+ class SerialLinkMasterPort;
+
+ /**
+ * The port on the side that receives requests and sends
+ * responses. The slave port has a set of address ranges that it
+ * is responsible for. The slave port also has a buffer for the
+ * responses not yet sent.
+ */
+ class SerialLinkSlavePort : public SlavePort
+ {
+
+ private:
+
+ /** The serial_link to which this port belongs. */
+ SerialLink& serial_link;
+
+ /**
+ * Master port on the other side of the serial_link.
+ */
+ SerialLinkMasterPort& masterPort;
+
+ /** Minimum request delay though this serial_link. */
+ const Cycles delay;
+
+ /** Address ranges to pass through the serial_link */
+ const AddrRangeList ranges;
+
+ /**
+ * Response packet queue. Response packets are held in this
+ * queue for a specified delay to model the processing delay
+ * of the serial_link. We use a deque as we need to iterate over
+ * the items for functional accesses.
+ */
+ std::deque<DeferredPacket> transmitList;
+
+ /** Counter to track the outstanding responses. */
+ unsigned int outstandingResponses;
+
+ /** If we should send a retry when space becomes available. */
+ bool retryReq;
+
+ /** Max queue size for reserved responses. */
+ unsigned int respQueueLimit;
+
+ /**
+ * Is this side blocked from accepting new response packets.
+ *
+ * @return true if the reserved space has reached the set limit
+ */
+ bool respQueueFull() const;
+
+ /**
+ * Handle send event, scheduled when the packet at the head of
+ * the response queue is ready to transmit (for timing
+ * accesses only).
+ */
+ void trySendTiming();
+
+ /** Send event for the response queue. */
+ EventWrapper<SerialLinkSlavePort,
+ &SerialLinkSlavePort::trySendTiming> sendEvent;
+
+ public:
+
+ /**
+ * Constructor for the SerialLinkSlavePort.
+ *
+ * @param _name the port name including the owner
+ * @param _serial_link the structural owner
+ * @param _masterPort the master port on the other side of the
+ * serial_link
+ * @param _delay the delay in cycles from receiving to sending
+ * @param _resp_limit the size of the response queue
+ * @param _ranges a number of address ranges to forward
+ */
+ SerialLinkSlavePort(const std::string& _name, SerialLink&
+ _serial_link, SerialLinkMasterPort& _masterPort,
+ Cycles _delay, int _resp_limit, const
+ std::vector<AddrRange>& _ranges);
+
+ /**
+ * Queue a response packet to be sent out later and also schedule
+ * a send if necessary.
+ *
+ * @param pkt a response to send out after a delay
+ * @param when tick when response packet should be sent
+ */
+ void schedTimingResp(PacketPtr pkt, Tick when);
+
+ /**
+ * Retry any stalled request that we have failed to accept at
+ * an earlier point in time. This call will do nothing if no
+ * request is waiting.
+ */
+ void retryStalledReq();
+
+ protected:
+
+ /** When receiving a timing request from the peer port,
+ pass it to the serial_link. */
+ bool recvTimingReq(PacketPtr pkt);
+
+ /** When receiving a retry request from the peer port,
+ pass it to the serial_link. */
+ void recvRespRetry();
+
+ /** When receiving a Atomic requestfrom the peer port,
+ pass it to the serial_link. */
+ Tick recvAtomic(PacketPtr pkt);
+
+ /** When receiving a Functional request from the peer port,
+ pass it to the serial_link. */
+ void recvFunctional(PacketPtr pkt);
+
+ /** When receiving a address range request the peer port,
+ pass it to the serial_link. */
+ AddrRangeList getAddrRanges() const;
+ };
+
+
+ /**
+ * Port on the side that forwards requests and receives
+ * responses. The master port has a buffer for the requests not
+ * yet sent.
+ */
+ class SerialLinkMasterPort : public MasterPort
+ {
+
+ private:
+
+ /** The serial_link to which this port belongs. */
+ SerialLink& serial_link;
+
+ /**
+ * The slave port on the other side of the serial_link.
+ */
+ SerialLinkSlavePort& slavePort;
+
+ /** Minimum delay though this serial_link. */
+ const Cycles delay;
+
+ /**
+ * Request packet queue. Request packets are held in this
+ * queue for a specified delay to model the processing delay
+ * of the serial_link. We use a deque as we need to iterate over
+ * the items for functional accesses.
+ */
+ std::deque<DeferredPacket> transmitList;
+
+ /** Max queue size for request packets */
+ const unsigned int reqQueueLimit;
+
+ /**
+ * Handle send event, scheduled when the packet at the head of
+ * the outbound queue is ready to transmit (for timing
+ * accesses only).
+ */
+ void trySendTiming();
+
+ /** Send event for the request queue. */
+ EventWrapper<SerialLinkMasterPort,
+ &SerialLinkMasterPort::trySendTiming> sendEvent;
+
+ public:
+
+ /**
+ * Constructor for the SerialLinkMasterPort.
+ *
+ * @param _name the port name including the owner
+ * @param _serial_link the structural owner
+ * @param _slavePort the slave port on the other side of the
+ * serial_link
+ * @param _delay the delay in cycles from receiving to sending
+ * @param _req_limit the size of the request queue
+ */
+ SerialLinkMasterPort(const std::string& _name, SerialLink&
+ _serial_link, SerialLinkSlavePort& _slavePort, Cycles
+ _delay, int _req_limit);
+
+ /**
+ * Is this side blocked from accepting new request packets.
+ *
+ * @return true if the occupied space has reached the set limit
+ */
+ bool reqQueueFull() const;
+
+ /**
+ * Queue a request packet to be sent out later and also schedule
+ * a send if necessary.
+ *
+ * @param pkt a request to send out after a delay
+ * @param when tick when response packet should be sent
+ */
+ void schedTimingReq(PacketPtr pkt, Tick when);
+
+ /**
+ * Check a functional request against the packets in our
+ * request queue.
+ *
+ * @param pkt packet to check against
+ *
+ * @return true if we find a match
+ */
+ bool checkFunctional(PacketPtr pkt);
+
+ protected:
+
+ /** When receiving a timing request from the peer port,
+ pass it to the serial_link. */
+ bool recvTimingResp(PacketPtr pkt);
+
+ /** When receiving a retry request from the peer port,
+ pass it to the serial_link. */
+ void recvReqRetry();
+ };
+
+ /** Slave port of the serial_link. */
+ SerialLinkSlavePort slavePort;
+
+ /** Master port of the serial_link. */
+ SerialLinkMasterPort masterPort;
+
+ /** Number of parallel lanes in this serial link */
+ unsigned num_lanes;
+
+ public:
+
+ virtual BaseMasterPort& getMasterPort(const std::string& if_name,
+ PortID idx = InvalidPortID);
+ virtual BaseSlavePort& getSlavePort(const std::string& if_name,
+ PortID idx = InvalidPortID);
+
+ virtual void init();
+
+ typedef SerialLinkParams Params;
+
+ SerialLink(SerialLinkParams *p);
+};
+
+#endif //__MEM_SERIAL_LINK_HH__