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
  29 /**
  30  * @file
  31  * Port Object Decleration. Ports are used to interface memory objects to
  32  * each other.  They will always come in pairs, and we refer to the other
  33  * port object as the peer.  These are used to make the design more
  34  * modular so that a specific interface between every type of objcet doesn't
  35  * have to be created.
  36  */
  37
  38 #ifndef __MEM_PORT_HH__
  39 #define __MEM_PORT_HH__
  40
  41 #include <list>
  42 #include <inttypes.h>
  43
  44 #include "base/misc.hh"
  45 #include "base/range.hh"
  46 #include "mem/packet.hh"
  47 #include "mem/request.hh"
  48
  49 /** This typedef is used to clean up the parameter list of
  50  * getDeviceAddressRanges() and getPeerAddressRanges().  It's declared
  51  * outside the Port object since it's also used by some mem objects.
  52  * Eventually we should move this typedef to wherever Addr is
  53  * defined.
  54  */
  55
  56 typedef std::list<Range<Addr> > AddrRangeList;
  57 typedef std::list<Range<Addr> >::iterator AddrRangeIter;
  58
  59 /**
  60  * Ports are used to interface memory objects to
  61  * each other.  They will always come in pairs, and we refer to the other
  62  * port object as the peer.  These are used to make the design more
  63  * modular so that a specific interface between every type of objcet doesn't
  64  * have to be created.
  65  *
  66  * Recv accesor functions are being called from the peer interface.
  67  * Send accessor functions are being called from the device the port is
  68  * associated with, and it will call the peer recv. accessor function.
  69  */
  70 class Port
  71 {
  72   public:
  73
  74     virtual ~Port() {};
  75     // mey be better to use subclasses & RTTI?
  76     /** Holds the ports status.  Keeps track if it is blocked, or has
  77         calculated a range change. */
  78     enum Status {
  79         Blocked,
  80         Unblocked,
  81         RangeChange
  82     };
  83
  84   private:
  85
  86     /** A pointer to the peer port.  Ports always come in pairs, that way they
  87         can use a standardized interface to communicate between different
  88         memory objects. */
  89     Port *peer;
  90
  91   public:
  92
  93     /** Function to set the pointer for the peer port.
  94         @todo should be called by the configuration stuff (python).
  95     */
  96     void setPeer(Port *port) { peer = port; }
  97
  98         /** Function to set the pointer for the peer port.
  99         @todo should be called by the configuration stuff (python).
 100     */
 101     Port *getPeer() { return peer; }
 102
 103   protected:
 104
 105     /** These functions are protected because they should only be
 106      * called by a peer port, never directly by any outside object. */
 107
 108     /** Called to recive a timing call from the peer port. */
 109     virtual bool recvTiming(Packet *pkt) = 0;
 110
 111     /** Called to recive a atomic call from the peer port. */
 112     virtual Tick recvAtomic(Packet *pkt) = 0;
 113
 114     /** Called to recive a functional call from the peer port. */
 115     virtual void recvFunctional(Packet *pkt) = 0;
 116
 117     /** Called to recieve a status change from the peer port. */
 118     virtual void recvStatusChange(Status status) = 0;
 119
 120     /** Called by a peer port if the send was unsuccesful, and had to
 121         wait.  This shouldn't be valid for response paths (IO Devices).
 122         so it is set to panic if it isn't already defined.
 123     */
 124     virtual Packet *recvRetry() { panic("??"); }
 125
 126     /** Called by a peer port in order to determine the block size of the
 127         device connected to this port.  It sometimes doesn't make sense for
 128         this function to be called, a DMA interface doesn't really have a
 129         block size, so it is defaulted to a panic.
 130     */
 131     virtual int deviceBlockSize() { panic("??"); }
 132
 133     /** The peer port is requesting us to reply with a list of the ranges we
 134         are responsible for.
 135         @param resp is a list of ranges responded to
 136         @param snoop is a list of ranges snooped
 137     */
 138     virtual void getDeviceAddressRanges(AddrRangeList &resp,
 139             AddrRangeList &snoop)
 140     { panic("??"); }
 141
 142   public:
 143
 144     /** Function called by associated memory device (cache, memory, iodevice)
 145         in order to send a timing request to the port.  Simply calls the peer
 146         port receive function.
 147         @return This function returns if the send was succesful in it's
 148         recieve. If it was a failure, then the port will wait for a recvRetry
 149         at which point it can issue a successful sendTiming.  This is used in
 150         case a cache has a higher priority request come in while waiting for
 151         the bus to arbitrate.
 152     */
 153     bool sendTiming(Packet *pkt) { return peer->recvTiming(pkt); }
 154
 155     /** Function called by the associated device to send an atomic access,
 156         an access in which the data is moved and the state is updated in one
 157         cycle, without interleaving with other memory accesses.
 158     */
 159     Tick sendAtomic(Packet *pkt)
 160         { return peer->recvAtomic(pkt); }
 161
 162     /** Function called by the associated device to send a functional access,
 163         an access in which the data is instantly updated everywhere in the
 164         memory system, without affecting the current state of any block or
 165         moving the block.
 166     */
 167     void sendFunctional(Packet *pkt)
 168         { return peer->recvFunctional(pkt); }
 169
 170     /** Called by the associated device to send a status change to the device
 171         connected to the peer interface.
 172     */
 173     void sendStatusChange(Status status) {peer->recvStatusChange(status); }
 174
 175     /** When a timing access doesn't return a success, some time later the
 176         Retry will be sent.
 177     */
 178     Packet *sendRetry() { return peer->recvRetry(); }
 179
 180     /** Called by the associated device if it wishes to find out the blocksize
 181         of the device on attached to the peer port.
 182     */
 183     int peerBlockSize() { return peer->deviceBlockSize(); }
 184
 185     /** Called by the associated device if it wishes to find out the address
 186         ranges connected to the peer ports devices.
 187     */
 188     void getPeerAddressRanges(AddrRangeList &resp, AddrRangeList &snoop)
 189     { peer->getDeviceAddressRanges(resp, snoop); }
 190
 191     /** This function is a wrapper around sendFunctional()
 192         that breaks a larger, arbitrarily aligned access into
 193         appropriate chunks.  The default implementation can use
 194         getBlockSize() to determine the block size and go from there.
 195     */
 196     virtual void readBlob(Addr addr, uint8_t *p, int size);
 197
 198     /** This function is a wrapper around sendFunctional()
 199         that breaks a larger, arbitrarily aligned access into
 200         appropriate chunks.  The default implementation can use
 201         getBlockSize() to determine the block size and go from there.
 202     */
 203     virtual void writeBlob(Addr addr, uint8_t *p, int size);
 204
 205     /** Fill size bytes starting at addr with byte value val.  This
 206         should not need to be virtual, since it can be implemented in
 207         terms of writeBlob().  However, it shouldn't be
 208         performance-critical either, so it could be if we wanted to.
 209     */
 210     virtual void memsetBlob(Addr addr, uint8_t val, int size);
 211
 212   private:
 213
 214     /** Internal helper function for read/writeBlob().
 215      */
 216     void blobHelper(Addr addr, uint8_t *p, int size, Command cmd);
 217 };
 218
 219 /** A simple functional port that is only meant for one way communication to
 220  * physical memory. It is only meant to be used to load data into memory before
 221  * the simulation begins.
 222  */
 223
 224 class FunctionalPort : public Port
 225 {
 226   public:
 227     virtual bool recvTiming(Packet *pkt) { panic("FuncPort is UniDir"); }
 228     virtual Tick recvAtomic(Packet *pkt) { panic("FuncPort is UniDir"); }
 229     virtual void recvFunctional(Packet *pkt) { panic("FuncPort is UniDir"); }
 230     virtual void recvStatusChange(Status status) {}
 231
 232     template <typename T>
 233     inline void write(Addr addr, T d)
 234     {
 235         writeBlob(addr, (uint8_t*)&d, sizeof(T));
 236     }
 237
 238     template <typename T>
 239     inline T read(Addr addr)
 240     {
 241         T d;
 242         readBlob(addr, (uint8_t*)&d, sizeof(T));
 243         return d;
 244     }
 245 };
 246
 247 #endif //__MEM_PORT_HH__