src/mem/noncoherent_xbar.hh

   1 /*
   2  * Copyright (c) 2011-2015 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
   7  * property including but not limited to intellectual property relating
   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Copyright (c) 2002-2005 The Regents of The University of Michigan
  15  * All rights reserved.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions are
  19  * met: redistributions of source code must retain the above copyright
  20  * notice, this list of conditions and the following disclaimer;
  21  * redistributions in binary form must reproduce the above copyright
  22  * notice, this list of conditions and the following disclaimer in the
  23  * documentation and/or other materials provided with the distribution;
  24  * neither the name of the copyright holders nor the names of its
  25  * contributors may be used to endorse or promote products derived from
  26  * this software without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  29  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  30  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  31  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  32  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  33  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  34  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  35  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  36  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  37  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  38  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  39  *
  40  * Authors: Ron Dreslinski
  41  *          Ali Saidi
  42  *          Andreas Hansson
  43  *          William Wang
  44  */
  45
  46 /**
  47  * @file
  48  * Declaration of a non-coherent crossbar.
  49  */
  50
  51 #ifndef __MEM_NONCOHERENT_XBAR_HH__
  52 #define __MEM_NONCOHERENT_XBAR_HH__
  53
  54 #include "mem/xbar.hh"
  55 #include "params/NoncoherentXBar.hh"
  56
  57 /**
  58  * A non-coherent crossbar connects a number of non-snooping masters
  59  * and slaves, and routes the request and response packets based on
  60  * the address. The request packets issued by the master connected to
  61  * a non-coherent crossbar could still snoop in caches attached to a
  62  * coherent crossbar, as is the case with the I/O bus and memory bus
  63  * in most system configurations. No snoops will, however, reach any
  64  * master on the non-coherent crossbar itself.
  65  *
  66  * The non-coherent crossbar can be used as a template for modelling
  67  * PCIe, and non-coherent AMBA and OCP buses, and is typically used
  68  * for the I/O buses.
  69  */
  70 class NoncoherentXBar : public BaseXBar
  71 {
  72
  73   protected:
  74
  75     /**
  76      * Declare the layers of this crossbar, one vector for requests
  77      * and one for responses.
  78      */
  79     std::vector<ReqLayer*> reqLayers;
  80     std::vector<RespLayer*> respLayers;
  81
  82     /**
  83      * Declaration of the non-coherent crossbar slave port type, one
  84      * will be instantiated for each of the master ports connecting to
  85      * the crossbar.
  86      */
  87     class NoncoherentXBarSlavePort : public QueuedSlavePort
  88     {
  89       private:
  90
  91         /** A reference to the crossbar to which this port belongs. */
  92         NoncoherentXBar &xbar;
  93
  94         /** A normal packet queue used to store responses. */
  95         RespPacketQueue queue;
  96
  97       public:
  98
  99         NoncoherentXBarSlavePort(const std::string &_name,
 100                                 NoncoherentXBar &_xbar, PortID _id)
 101             : QueuedSlavePort(_name, &_xbar, queue, _id), xbar(_xbar),
 102               queue(_xbar, *this)
 103         { }
 104
 105       protected:
 106
 107         /**
 108          * When receiving a timing request, pass it to the crossbar.
 109          */
 110         virtual bool recvTimingReq(PacketPtr pkt)
 111         { return xbar.recvTimingReq(pkt, id); }
 112
 113         /**
 114          * When receiving an atomic request, pass it to the crossbar.
 115          */
 116         virtual Tick recvAtomic(PacketPtr pkt)
 117         { return xbar.recvAtomic(pkt, id); }
 118
 119         /**
 120          * When receiving a functional request, pass it to the crossbar.
 121          */
 122         virtual void recvFunctional(PacketPtr pkt)
 123         { xbar.recvFunctional(pkt, id); }
 124
 125         /**
 126          * Return the union of all adress ranges seen by this crossbar.
 127          */
 128         virtual AddrRangeList getAddrRanges() const
 129         { return xbar.getAddrRanges(); }
 130
 131     };
 132
 133     /**
 134      * Declaration of the crossbar master port type, one will be
 135      * instantiated for each of the slave ports connecting to the
 136      * crossbar.
 137      */
 138     class NoncoherentXBarMasterPort : public MasterPort
 139     {
 140       private:
 141
 142         /** A reference to the crossbar to which this port belongs. */
 143         NoncoherentXBar &xbar;
 144
 145       public:
 146
 147         NoncoherentXBarMasterPort(const std::string &_name,
 148                                  NoncoherentXBar &_xbar, PortID _id)
 149             : MasterPort(_name, &_xbar, _id), xbar(_xbar)
 150         { }
 151
 152       protected:
 153
 154         /**
 155          * When receiving a timing response, pass it to the crossbar.
 156          */
 157         virtual bool recvTimingResp(PacketPtr pkt)
 158         { return xbar.recvTimingResp(pkt, id); }
 159
 160         /** When reciving a range change from the peer port (at id),
 161             pass it to the crossbar. */
 162         virtual void recvRangeChange()
 163         { xbar.recvRangeChange(id); }
 164
 165         /** When reciving a retry from the peer port (at id),
 166             pass it to the crossbar. */
 167         virtual void recvReqRetry()
 168         { xbar.recvReqRetry(id); }
 169
 170     };
 171
 172     /** Function called by the port when the crossbar is recieving a Timing
 173       request packet.*/
 174     virtual bool recvTimingReq(PacketPtr pkt, PortID slave_port_id);
 175
 176     /** Function called by the port when the crossbar is recieving a Timing
 177       response packet.*/
 178     virtual bool recvTimingResp(PacketPtr pkt, PortID master_port_id);
 179
 180     /** Timing function called by port when it is once again able to process
 181      * requests. */
 182     void recvReqRetry(PortID master_port_id);
 183
 184     /** Function called by the port when the crossbar is recieving a Atomic
 185       transaction.*/
 186     Tick recvAtomic(PacketPtr pkt, PortID slave_port_id);
 187
 188     /** Function called by the port when the crossbar is recieving a Functional
 189         transaction.*/
 190     void recvFunctional(PacketPtr pkt, PortID slave_port_id);
 191
 192   public:
 193
 194     NoncoherentXBar(const NoncoherentXBarParams *p);
 195
 196     virtual ~NoncoherentXBar();
 197
 198     /**
 199      * stats
 200      */
 201     virtual void regStats();
 202     Stats::Scalar totPktSize;
 203 };
 204
 205 #endif //__MEM_NONCOHERENT_XBAR_HH__