src/mem/port.hh

   1 /*
   2  * Copyright (c) 2002-2005 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * Authors: Ron Dreslinski
  29  */
  30
  31 /**
  32  * @file
  33  * Port Object Declaration. Ports are used to interface memory objects to
  34  * each other.  They will always come in pairs, and we refer to the other
  35  * port object as the peer.  These are used to make the design more
  36  * modular so that a specific interface between every type of objcet doesn't
  37  * have to be created.
  38  */
  39
  40 #ifndef __MEM_PORT_HH__
  41 #define __MEM_PORT_HH__
  42
  43 #include <list>
  44 #include <inttypes.h>
  45
  46 #include "base/misc.hh"
  47 #include "base/range.hh"
  48 #include "mem/packet.hh"
  49 #include "mem/request.hh"
  50
  51 /** This typedef is used to clean up the parameter list of
  52  * getDeviceAddressRanges() and getPeerAddressRanges().  It's declared
  53  * outside the Port object since it's also used by some mem objects.
  54  * Eventually we should move this typedef to wherever Addr is
  55  * defined.
  56  */
  57
  58 typedef std::list<Range<Addr> > AddrRangeList;
  59 typedef std::list<Range<Addr> >::iterator AddrRangeIter;
  60
  61 /**
  62  * Ports are used to interface memory objects to
  63  * each other.  They will always come in pairs, and we refer to the other
  64  * port object as the peer.  These are used to make the design more
  65  * modular so that a specific interface between every type of objcet doesn't
  66  * have to be created.
  67  *
  68  * Recv accesor functions are being called from the peer interface.
  69  * Send accessor functions are being called from the device the port is
  70  * associated with, and it will call the peer recv. accessor function.
  71  */
  72 class Port
  73 {
  74   private:
  75
  76     /** Descriptive name (for DPRINTF output) */
  77     mutable std::string portName;
  78
  79     /** A pointer to the peer port.  Ports always come in pairs, that way they
  80         can use a standardized interface to communicate between different
  81         memory objects. */
  82     Port *peer;
  83
  84   public:
  85
  86     Port()
  87         : peer(NULL)
  88     { }
  89
  90     /**
  91      * Constructor.
  92      *
  93      * @param _name Port name for DPRINTF output.  Should include name
  94      * of memory system object to which the port belongs.
  95      */
  96     Port(const std::string &_name)
  97         : portName(_name), peer(NULL)
  98     { }
  99
 100     /** Return port name (for DPRINTF). */
 101     const std::string &name() const { return portName; }
 102
 103     virtual ~Port() {};
 104
 105     // mey be better to use subclasses & RTTI?
 106     /** Holds the ports status.  Currently just that a range recomputation needs
 107      * to be done. */
 108     enum Status {
 109         RangeChange,
 110         SnoopSquash
 111     };
 112
 113     void setName(const std::string &name)
 114     { portName = name; }
 115
 116     /** Function to set the pointer for the peer port.
 117         @todo should be called by the configuration stuff (python).
 118     */
 119     void setPeer(Port *port);
 120
 121     /** Function to set the pointer for the peer port.
 122         @todo should be called by the configuration stuff (python).
 123     */
 124     Port *getPeer() { return peer; }
 125
 126   protected:
 127
 128     /** These functions are protected because they should only be
 129      * called by a peer port, never directly by any outside object. */
 130
 131     /** Called to recive a timing call from the peer port. */
 132     virtual bool recvTiming(Packet *pkt) = 0;
 133
 134     /** Called to recive a atomic call from the peer port. */
 135     virtual Tick recvAtomic(Packet *pkt) = 0;
 136
 137     /** Called to recive a functional call from the peer port. */
 138     virtual void recvFunctional(Packet *pkt) = 0;
 139
 140     /** Called to recieve a status change from the peer port. */
 141     virtual void recvStatusChange(Status status) = 0;
 142
 143     /** Called by a peer port if the send was unsuccesful, and had to
 144         wait.  This shouldn't be valid for response paths (IO Devices).
 145         so it is set to panic if it isn't already defined.
 146     */
 147     virtual void recvRetry() { panic("??"); }
 148
 149     /** Called by a peer port in order to determine the block size of the
 150         device connected to this port.  It sometimes doesn't make sense for
 151         this function to be called, a DMA interface doesn't really have a
 152         block size, so it is defaulted to a panic.
 153     */
 154     virtual int deviceBlockSize() { panic("??"); }
 155
 156     /** The peer port is requesting us to reply with a list of the ranges we
 157         are responsible for.
 158         @param resp is a list of ranges responded to
 159         @param snoop is a list of ranges snooped
 160     */
 161     virtual void getDeviceAddressRanges(AddrRangeList &resp,
 162             AddrRangeList &snoop)
 163     { panic("??"); }
 164
 165   public:
 166
 167     /** Function called by associated memory device (cache, memory, iodevice)
 168         in order to send a timing request to the port.  Simply calls the peer
 169         port receive function.
 170         @return This function returns if the send was succesful in it's
 171         recieve. If it was a failure, then the port will wait for a recvRetry
 172         at which point it can possibly issue a successful sendTiming.  This is used in
 173         case a cache has a higher priority request come in while waiting for
 174         the bus to arbitrate.
 175     */
 176     bool sendTiming(Packet *pkt) { return peer->recvTiming(pkt); }
 177
 178     /** Function called by the associated device to send an atomic
 179      *   access, an access in which the data is moved and the state is
 180      *   updated in one cycle, without interleaving with other memory
 181      *   accesses.  Returns estimated latency of access.
 182      */
 183     Tick sendAtomic(Packet *pkt)
 184         { return peer->recvAtomic(pkt); }
 185
 186     /** Function called by the associated device to send a functional access,
 187         an access in which the data is instantly updated everywhere in the
 188         memory system, without affecting the current state of any block or
 189         moving the block.
 190     */
 191     void sendFunctional(Packet *pkt)
 192         { return peer->recvFunctional(pkt); }
 193
 194     /** Called by the associated device to send a status change to the device
 195         connected to the peer interface.
 196     */
 197     void sendStatusChange(Status status) {peer->recvStatusChange(status); }
 198
 199     /** When a timing access doesn't return a success, some time later the
 200         Retry will be sent.
 201     */
 202     void sendRetry() { return peer->recvRetry(); }
 203
 204     /** Called by the associated device if it wishes to find out the blocksize
 205         of the device on attached to the peer port.
 206     */
 207     int peerBlockSize() { return peer->deviceBlockSize(); }
 208
 209     /** Called by the associated device if it wishes to find out the address
 210         ranges connected to the peer ports devices.
 211     */
 212     void getPeerAddressRanges(AddrRangeList &resp, AddrRangeList &snoop)
 213     { peer->getDeviceAddressRanges(resp, snoop); }
 214
 215     /** This function is a wrapper around sendFunctional()
 216         that breaks a larger, arbitrarily aligned access into
 217         appropriate chunks.  The default implementation can use
 218         getBlockSize() to determine the block size and go from there.
 219     */
 220     virtual void readBlob(Addr addr, uint8_t *p, int size);
 221
 222     /** This function is a wrapper around sendFunctional()
 223         that breaks a larger, arbitrarily aligned access into
 224         appropriate chunks.  The default implementation can use
 225         getBlockSize() to determine the block size and go from there.
 226     */
 227     virtual void writeBlob(Addr addr, uint8_t *p, int size);
 228
 229     /** Fill size bytes starting at addr with byte value val.  This
 230         should not need to be virtual, since it can be implemented in
 231         terms of writeBlob().  However, it shouldn't be
 232         performance-critical either, so it could be if we wanted to.
 233     */
 234     virtual void memsetBlob(Addr addr, uint8_t val, int size);
 235
 236   private:
 237
 238     /** Internal helper function for read/writeBlob().
 239      */
 240     void blobHelper(Addr addr, uint8_t *p, int size, Packet::Command cmd);
 241 };
 242
 243 /** A simple functional port that is only meant for one way communication to
 244  * physical memory. It is only meant to be used to load data into memory before
 245  * the simulation begins.
 246  */
 247
 248 class FunctionalPort : public Port
 249 {
 250   public:
 251     FunctionalPort(const std::string &_name)
 252         : Port(_name)
 253     {}
 254
 255   protected:
 256     virtual bool recvTiming(Packet *pkt) { panic("FuncPort is UniDir"); }
 257     virtual Tick recvAtomic(Packet *pkt) { panic("FuncPort is UniDir"); }
 258     virtual void recvFunctional(Packet *pkt) { panic("FuncPort is UniDir"); }
 259     virtual void recvStatusChange(Status status) {}
 260
 261   public:
 262     /** a write function that also does an endian conversion. */
 263     template <typename T>
 264     inline void writeHtoG(Addr addr, T d);
 265
 266     /** a read function that also does an endian conversion. */
 267     template <typename T>
 268     inline T readGtoH(Addr addr);
 269
 270     template <typename T>
 271     inline void write(Addr addr, T d)
 272     {
 273         writeBlob(addr, (uint8_t*)&d, sizeof(T));
 274     }
 275
 276     template <typename T>
 277     inline T read(Addr addr)
 278     {
 279         T d;
 280         readBlob(addr, (uint8_t*)&d, sizeof(T));
 281         return d;
 282     }
 283 };
 284
 285 #endif //__MEM_PORT_HH__