src/mem/external_slave.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
   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  * 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
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 /**
  39  * @file
  40  *
  41  * ExternalSlave is a memory object representing a binding from
  42  * a gem5 master to a slave 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 SlavePort which can be bound.
  52  *
  53  * The external port must provide a gem5 SlavePort interface (with the
  54  * exception of getAddrRanges which is provided by the ExternalSlave
  55  * object).
  56  */
  57
  58 #ifndef __MEM_EXTERNAL_SLAVE_HH__
  59 #define __MEM_EXTERNAL_SLAVE_HH__
  60
  61 #include "mem/port.hh"
  62 #include "params/ExternalSlave.hh"
  63 #include "sim/sim_object.hh"
  64
  65 class ExternalSlave : public SimObject
  66 {
  67   public:
  68     /** Derive from this class to create an external port interface */
  69     class ExternalPort : public SlavePort
  70     {
  71       protected:
  72         ExternalSlave &owner;
  73
  74       public:
  75         ExternalPort(const std::string &name_,
  76             ExternalSlave &owner_) :
  77             SlavePort(name_, &owner_), owner(owner_)
  78         { }
  79
  80         ~ExternalPort() { }
  81
  82         /** Any or all of recv... can be overloaded to provide the port's
  83          *  functionality */
  84
  85         AddrRangeList getAddrRanges() const;
  86     };
  87
  88     /* Handlers are specific to *types* of port not specific port
  89      * instantiations.  A handler will typically build a bridge to the
  90      * external port from gem5 and provide gem5 with a SlavePort that can be
  91      * bound to for each call to Handler::getExternalPort.*/
  92     class Handler
  93     {
  94       public:
  95         /** Create or find an external port which can be bound.  Returns
  96          *  NULL on failure */
  97         virtual ExternalPort *getExternalPort(
  98             const std::string &name, ExternalSlave &owner,
  99             const std::string &port_data) = 0;
 100     };
 101
 102   protected:
 103     /** The peer port for the gem5 port "port" */
 104     ExternalPort *externalPort;
 105
 106     /** Name of the bound port.  This will be name() + ".port" */
 107     std::string portName;
 108
 109     /** Key to select a port handler */
 110     std::string portType;
 111
 112     /** Handler-specific port configuration */
 113     std::string portData;
 114
 115     /** The Range of addresses supported by the devices on the external
 116      *  side of this port */
 117     AddrRangeList addrRanges;
 118
 119     /** Registered handlers.  Handlers are chosen using the port_type
 120      *  parameter on ExternalSlaves.  port_types form a global namespace
 121      *  across the simulation and so handlers are registered into a global
 122      *  structure */
 123     static std::map<std::string, Handler *> portHandlers;
 124
 125   public:
 126     ExternalSlave(ExternalSlaveParams *params);
 127
 128     /** Port interface.  Responds only to port "port" */
 129     Port &getPort(const std::string &if_name,
 130                   PortID idx=InvalidPortID) override;
 131
 132     /** Register a handler which can provide ports with port_type ==
 133      *  handler_name */
 134     static void registerHandler(const std::string &handler_name,
 135         Handler *handler);
 136
 137     void init() override;
 138 };
 139
 140
 141 #endif //__MEM_EXTERNAL_SLAVE_HH__