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     };
 111
 112     void setName(const std::string &name)
 113     { portName = name; }
 114
 115     /** Function to set the pointer for the peer port.
 116         @todo should be called by the configuration stuff (python).
 117     */
 118     void setPeer(Port *port);
 119
 120     /** Function to set the pointer for the peer port.
 121         @todo should be called by the configuration stuff (python).
 122     */
 123     Port *getPeer() { return peer; }
 124
 125   protected:
 126
 127     /** These functions are protected because they should only be
 128      * called by a peer port, never directly by any outside object. */
 129
 130     /** Called to recive a timing call from the peer port. */
 131     virtual bool recvTiming(PacketPtr pkt) = 0;
 132
 133     /** Called to recive a atomic call from the peer port. */
 134     virtual Tick recvAtomic(PacketPtr pkt) = 0;
 135
 136     /** Called to recive a functional call from the peer port. */
 137     virtual void recvFunctional(PacketPtr pkt) = 0;
 138
 139     /** Called to recieve a status change from the peer port. */
 140     virtual void recvStatusChange(Status status) = 0;
 141
 142     /** Called by a peer port if the send was unsuccesful, and had to
 143         wait.  This shouldn't be valid for response paths (IO Devices).
 144         so it is set to panic if it isn't already defined.
 145     */
 146     virtual void recvRetry() { panic("??"); }
 147
 148     /** Called by a peer port in order to determine the block size of the
 149         device connected to this port.  It sometimes doesn't make sense for
 150         this function to be called, a DMA interface doesn't really have a
 151         block size, so it is defaulted to a panic.
 152     */
 153     virtual int deviceBlockSize() { panic("??"); }
 154
 155     /** The peer port is requesting us to reply with a list of the ranges we
 156         are responsible for.
 157         @param resp is a list of ranges responded to
 158         @param snoop is a list of ranges snooped
 159     */
 160     virtual void getDeviceAddressRanges(AddrRangeList &resp,
 161             AddrRangeList &snoop)
 162     { panic("??"); }
 163
 164   public:
 165
 166     /** Function called by associated memory device (cache, memory, iodevice)
 167         in order to send a timing request to the port.  Simply calls the peer
 168         port receive function.
 169         @return This function returns if the send was succesful in it's
 170         recieve. If it was a failure, then the port will wait for a recvRetry
 171         at which point it can possibly issue a successful sendTiming.  This is used in
 172         case a cache has a higher priority request come in while waiting for
 173         the bus to arbitrate.
 174     */
 175     bool sendTiming(PacketPtr pkt) { return peer->recvTiming(pkt); }
 176
 177     /** Function called by the associated device to send an atomic
 178      *   access, an access in which the data is moved and the state is
 179      *   updated in one cycle, without interleaving with other memory
 180      *   accesses.  Returns estimated latency of access.
 181      */
 182     Tick sendAtomic(PacketPtr pkt)
 183         { return peer->recvAtomic(pkt); }
 184
 185     /** Function called by the associated device to send a functional access,
 186         an access in which the data is instantly updated everywhere in the
 187         memory system, without affecting the current state of any block or
 188         moving the block.
 189     */
 190     void sendFunctional(PacketPtr pkt)
 191         { return peer->recvFunctional(pkt); }
 192
 193     /** Called by the associated device to send a status change to the device
 194         connected to the peer interface.
 195     */
 196     void sendStatusChange(Status status) {peer->recvStatusChange(status); }
 197
 198     /** When a timing access doesn't return a success, some time later the
 199         Retry will be sent.
 200     */
 201     void sendRetry() { return peer->recvRetry(); }
 202
 203     /** Called by the associated device if it wishes to find out the blocksize
 204         of the device on attached to the peer port.
 205     */
 206     int peerBlockSize() { return peer->deviceBlockSize(); }
 207
 208     /** Called by the associated device if it wishes to find out the address
 209         ranges connected to the peer ports devices.
 210     */
 211     void getPeerAddressRanges(AddrRangeList &resp, AddrRangeList &snoop)
 212     { peer->getDeviceAddressRanges(resp, snoop); }
 213
 214     /** This function is a wrapper around sendFunctional()
 215         that breaks a larger, arbitrarily aligned access into
 216         appropriate chunks.  The default implementation can use
 217         getBlockSize() to determine the block size and go from there.
 218     */
 219     virtual void readBlob(Addr addr, uint8_t *p, int size);
 220
 221     /** This function is a wrapper around sendFunctional()
 222         that breaks a larger, arbitrarily aligned access into
 223         appropriate chunks.  The default implementation can use
 224         getBlockSize() to determine the block size and go from there.
 225     */
 226     virtual void writeBlob(Addr addr, uint8_t *p, int size);
 227
 228     /** Fill size bytes starting at addr with byte value val.  This
 229         should not need to be virtual, since it can be implemented in
 230         terms of writeBlob().  However, it shouldn't be
 231         performance-critical either, so it could be if we wanted to.
 232     */
 233     virtual void memsetBlob(Addr addr, uint8_t val, int size);
 234
 235   private:
 236
 237     /** Internal helper function for read/writeBlob().
 238      */
 239     void blobHelper(Addr addr, uint8_t *p, int size, Packet::Command cmd);
 240 };
 241
 242 /** A simple functional port that is only meant for one way communication to
 243  * physical memory. It is only meant to be used to load data into memory before
 244  * the simulation begins.
 245  */
 246
 247 class FunctionalPort : public Port
 248 {
 249   public:
 250     FunctionalPort(const std::string &_name)
 251         : Port(_name)
 252     {}
 253
 254   protected:
 255     virtual bool recvTiming(PacketPtr pkt) { panic("FuncPort is UniDir"); }
 256     virtual Tick recvAtomic(PacketPtr pkt) { panic("FuncPort is UniDir"); }
 257     virtual void recvFunctional(PacketPtr pkt) { panic("FuncPort is UniDir"); }
 258     virtual void recvStatusChange(Status status) {}
 259
 260   public:
 261     /** a write function that also does an endian conversion. */
 262     template <typename T>
 263     inline void writeHtoG(Addr addr, T d);
 264
 265     /** a read function that also does an endian conversion. */
 266     template <typename T>
 267     inline T readGtoH(Addr addr);
 268
 269     template <typename T>
 270     inline void write(Addr addr, T d)
 271     {
 272         writeBlob(addr, (uint8_t*)&d, sizeof(T));
 273     }
 274
 275     template <typename T>
 276     inline T read(Addr addr)
 277     {
 278         T d;
 279         readBlob(addr, (uint8_t*)&d, sizeof(T));
 280         return d;
 281     }
 282 };
 283
 284 #endif //__MEM_PORT_HH__