src/mem/external_master.hh

   1 /*
   2  * Copyright (c) 2012-2014 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
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   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  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
  16  * met: redistributions of source code must retain the above copyright
  17  * notice, this list of conditions and the following disclaimer;
  18  * redistributions in binary form must reproduce the above copyright
  19  * notice, this list of conditions and the following disclaimer in the
  20  * documentation and/or other materials provided with the distribution;
  21  * neither the name of the copyright holders nor the names of its
  22  * contributors may be used to endorse or promote products derived from
  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 /**
  39  * @file
  40  *
  41  * ExternalMaster is a memory object representing a binding from
  42  * a gem5 slave to a master port in a system external to gem5.
  43  *
  44  * During initialisation, a `handler' for the port type specified in the
  45  * port's port_type parameter is found from the registered port handlers
  46  * provided with registerHandler.  Once a handler is found, it is passed the
  47  * port_data parameter of the port which can be used to identify the external
  48  * port which is to be bound to.  A port handler will usually construct a
  49  * bridge object in the external system to accomodate the port-to-port
  50  * mapping but this bridge is not exposed to gem5 other than be the
  51  * presentation of the RequestPort which can be bound.
  52  *
  53  * The external port must provide a gem5 RequestPort interface.
  54  */
  55
  56 #ifndef __MEM_EXTERNAL_MASTER_HH__
  57 #define __MEM_EXTERNAL_MASTER_HH__
  58
  59 #include "mem/port.hh"
  60 #include "params/ExternalMaster.hh"
  61 #include "sim/sim_object.hh"
  62
  63 class ExternalMaster : public SimObject
  64 {
  65   public:
  66     /** Derive from this class to create an external port interface */
  67     class ExternalPort : public RequestPort
  68     {
  69       protected:
  70         ExternalMaster &owner;
  71
  72       public:
  73         ExternalPort(const std::string &name_,
  74             ExternalMaster &owner_) :
  75             RequestPort(name_, &owner_), owner(owner_)
  76         { }
  77
  78         ~ExternalPort() { }
  79
  80         /** Any or all of recv... can be overloaded to provide the port's
  81          *  functionality */
  82     };
  83
  84     /* Handlers are specific to *types* of port not specific port
  85      * instantiations.  A handler will typically build a bridge to the
  86      * external port from gem5 and provide gem5 with a RequestPort that can be
  87      * bound to for each call to Handler::getExternalPort.*/
  88     class Handler
  89     {
  90       public:
  91         /** Create or find an external port which can be bound.  Returns
  92          *  NULL on failure */
  93         virtual ExternalPort *getExternalPort(
  94             const std::string &name, ExternalMaster &owner,
  95             const std::string &port_data) = 0;
  96     };
  97
  98   protected:
  99     /** The peer port for the gem5 port "port" */
 100     ExternalPort *externalPort;
 101
 102     /** Name of the bound port.  This will be name() + ".port" */
 103     std::string portName;
 104
 105     /** Key to select a port handler */
 106     std::string portType;
 107
 108     /** Handler-specific port configuration */
 109     std::string portData;
 110
 111     /** Registered handlers.  Handlers are chosen using the port_type
 112      *  parameter on ExternalMasters.  port_types form a global namespace
 113      *  across the simulation and so handlers are registered into a global
 114      *  structure */
 115     static std::map<std::string, Handler *> portHandlers;
 116
 117   public:
 118     ExternalMaster(ExternalMasterParams *params);
 119
 120     /** Port interface.  Responds only to port "port" */
 121     Port &getPort(const std::string &if_name,
 122                   PortID idx=InvalidPortID) override;
 123
 124     /** Register a handler which can provide ports with port_type ==
 125      *  handler_name */
 126     static void registerHandler(const std::string &handler_name,
 127         Handler *handler);
 128
 129     void init() override;
 130
 131     const MasterID masterId;
 132 };
 133
 134
 135 #endif //__MEM_EXTERNAL_MASTER_HH__