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 class MemObject;
  62
  63 /**
  64  * Ports are used to interface memory objects to
  65  * each other.  They will always come in pairs, and we refer to the other
  66  * port object as the peer.  These are used to make the design more
  67  * modular so that a specific interface between every type of objcet doesn't
  68  * have to be created.
  69  *
  70  * Recv accesor functions are being called from the peer interface.
  71  * Send accessor functions are being called from the device the port is
  72  * associated with, and it will call the peer recv. accessor function.
  73  */
  74 class Port
  75 {
  76   private:
  77
  78     /** Descriptive name (for DPRINTF output) */
  79     mutable std::string portName;
  80
  81     /** A pointer to the peer port.  Ports always come in pairs, that way they
  82         can use a standardized interface to communicate between different
  83         memory objects. */
  84     Port *peer;
  85
  86     /** A pointer to the MemObject that owns this port. This may not be set. */
  87     MemObject *owner;
  88
  89   public:
  90
  91     Port()
  92         : peer(NULL), owner(NULL)
  93     { }
  94
  95     /**
  96      * Constructor.
  97      *
  98      * @param _name Port name for DPRINTF output.  Should include name
  99      * of memory system object to which the port belongs.
 100      * @param _owner Pointer to the MemObject that owns this port.
 101      * Will not necessarily be set.
 102      */
 103     Port(const std::string &_name, MemObject *_owner = NULL)
 104         : portName(_name), peer(NULL), owner(_owner)
 105     { }
 106
 107     /** Return port name (for DPRINTF). */
 108     const std::string &name() const { return portName; }
 109
 110     virtual ~Port() {};
 111
 112     // mey be better to use subclasses & RTTI?
 113     /** Holds the ports status.  Currently just that a range recomputation needs
 114      * to be done. */
 115     enum Status {
 116         RangeChange
 117     };
 118
 119     void setName(const std::string &name)
 120     { portName = name; }
 121
 122     /** Function to set the pointer for the peer port. */
 123     virtual void setPeer(Port *port);
 124
 125     /** Function to get the pointer to the peer port. */
 126     Port *getPeer() { return peer; }
 127
 128     /** Function to set the owner of this port. */
 129     void setOwner(MemObject *_owner) { owner = _owner; }
 130
 131     /** Function to return the owner of this port. */
 132     MemObject *getOwner() { return owner; }
 133
 134     /** Inform the peer port to delete itself and notify it's owner about it's
 135      * demise. */
 136     void removeConn();
 137
 138
 139   protected:
 140
 141     /** These functions are protected because they should only be
 142      * called by a peer port, never directly by any outside object. */
 143
 144     /** Called to recive a timing call from the peer port. */
 145     virtual bool recvTiming(PacketPtr pkt) = 0;
 146
 147     /** Called to recive a atomic call from the peer port. */
 148     virtual Tick recvAtomic(PacketPtr pkt) = 0;
 149
 150     /** Called to recive a functional call from the peer port. */
 151     virtual void recvFunctional(PacketPtr pkt) = 0;
 152
 153     /** Called to recieve a status change from the peer port. */
 154     virtual void recvStatusChange(Status status) = 0;
 155
 156     /** Called by a peer port if the send was unsuccesful, and had to
 157         wait.  This shouldn't be valid for response paths (IO Devices).
 158         so it is set to panic if it isn't already defined.
 159     */
 160     virtual void recvRetry() { panic("??"); }
 161
 162     /** Called by a peer port in order to determine the block size of the
 163         device connected to this port.  It sometimes doesn't make sense for
 164         this function to be called, a DMA interface doesn't really have a
 165         block size, so it is defaulted to a panic.
 166     */
 167     virtual int deviceBlockSize() { panic("??"); M5_DUMMY_RETURN }
 168
 169     /** The peer port is requesting us to reply with a list of the ranges we
 170         are responsible for.
 171         @param resp is a list of ranges responded to
 172         @param snoop is a list of ranges snooped
 173     */
 174     virtual void getDeviceAddressRanges(AddrRangeList &resp,
 175             AddrRangeList &snoop)
 176     { panic("??"); }
 177
 178   public:
 179
 180     /** Function called by associated memory device (cache, memory, iodevice)
 181         in order to send a timing request to the port.  Simply calls the peer
 182         port receive function.
 183         @return This function returns if the send was succesful in it's
 184         recieve. If it was a failure, then the port will wait for a recvRetry
 185         at which point it can possibly issue a successful sendTiming.  This is used in
 186         case a cache has a higher priority request come in while waiting for
 187         the bus to arbitrate.
 188     */
 189     bool sendTiming(PacketPtr pkt) { return peer->recvTiming(pkt); }
 190
 191     /** Function called by the associated device to send an atomic
 192      *   access, an access in which the data is moved and the state is
 193      *   updated in one cycle, without interleaving with other memory
 194      *   accesses.  Returns estimated latency of access.
 195      */
 196     Tick sendAtomic(PacketPtr pkt)
 197         { return peer->recvAtomic(pkt); }
 198
 199     /** Function called by the associated device to send a functional access,
 200         an access in which the data is instantly updated everywhere in the
 201         memory system, without affecting the current state of any block or
 202         moving the block.
 203     */
 204     void sendFunctional(PacketPtr pkt)
 205         { return peer->recvFunctional(pkt); }
 206
 207     /** Called by the associated device to send a status change to the device
 208         connected to the peer interface.
 209     */
 210     void sendStatusChange(Status status) {peer->recvStatusChange(status); }
 211
 212     /** When a timing access doesn't return a success, some time later the
 213         Retry will be sent.
 214     */
 215     void sendRetry() { return peer->recvRetry(); }
 216
 217     /** Called by the associated device if it wishes to find out the blocksize
 218         of the device on attached to the peer port.
 219     */
 220     int peerBlockSize() { return peer->deviceBlockSize(); }
 221
 222     /** Called by the associated device if it wishes to find out the address
 223         ranges connected to the peer ports devices.
 224     */
 225     void getPeerAddressRanges(AddrRangeList &resp, AddrRangeList &snoop)
 226     { peer->getDeviceAddressRanges(resp, snoop); }
 227
 228     /** This function is a wrapper around sendFunctional()
 229         that breaks a larger, arbitrarily aligned access into
 230         appropriate chunks.  The default implementation can use
 231         getBlockSize() to determine the block size and go from there.
 232     */
 233     virtual void readBlob(Addr addr, uint8_t *p, int size);
 234
 235     /** This function is a wrapper around sendFunctional()
 236         that breaks a larger, arbitrarily aligned access into
 237         appropriate chunks.  The default implementation can use
 238         getBlockSize() to determine the block size and go from there.
 239     */
 240     virtual void writeBlob(Addr addr, uint8_t *p, int size);
 241
 242     /** Fill size bytes starting at addr with byte value val.  This
 243         should not need to be virtual, since it can be implemented in
 244         terms of writeBlob().  However, it shouldn't be
 245         performance-critical either, so it could be if we wanted to.
 246     */
 247     virtual void memsetBlob(Addr addr, uint8_t val, int size);
 248
 249   private:
 250
 251     /** Internal helper function for read/writeBlob().
 252      */
 253     void blobHelper(Addr addr, uint8_t *p, int size, MemCmd cmd);
 254 };
 255
 256 /** A simple functional port that is only meant for one way communication to
 257  * physical memory. It is only meant to be used to load data into memory before
 258  * the simulation begins.
 259  */
 260
 261 class FunctionalPort : public Port
 262 {
 263   public:
 264     FunctionalPort(const std::string &_name, MemObject *_owner = NULL)
 265         : Port(_name, _owner)
 266     {}
 267
 268   protected:
 269     virtual bool recvTiming(PacketPtr pkt) { panic("FuncPort is UniDir");
 270         M5_DUMMY_RETURN }
 271     virtual Tick recvAtomic(PacketPtr pkt) { panic("FuncPort is UniDir");
 272         M5_DUMMY_RETURN }
 273     virtual void recvFunctional(PacketPtr pkt) { panic("FuncPort is UniDir"); }
 274     virtual void recvStatusChange(Status status) {}
 275
 276   public:
 277     /** a write function that also does an endian conversion. */
 278     template <typename T>
 279     inline void writeHtoG(Addr addr, T d);
 280
 281     /** a read function that also does an endian conversion. */
 282     template <typename T>
 283     inline T readGtoH(Addr addr);
 284
 285     template <typename T>
 286     inline void write(Addr addr, T d)
 287     {
 288         writeBlob(addr, (uint8_t*)&d, sizeof(T));
 289     }
 290
 291     template <typename T>
 292     inline T read(Addr addr)
 293     {
 294         T d;
 295         readBlob(addr, (uint8_t*)&d, sizeof(T));
 296         return d;
 297     }
 298 };
 299
 300 #endif //__MEM_PORT_HH__