port.hh revision 2519 
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 <string>
42#include <list>
43#include <inttypes.h>
44
45#include "base/misc.hh"
46#include "base/range.hh"
47#include "mem/packet.hh"
48#include "mem/request.hh"
49
50/** This typedef is used to clean up the parameter list of
51 * getDeviceAddressRanges() and getPeerAddressRanges().  It's declared
52 * outside the Port object since it's also used by some mem objects.
53 * Eventually we should move this typedef to wherever Addr is
54 * defined.
55 */
56
57typedef std::list<Range<Addr> > AddrRangeList;
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 */
70class 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 owner is an output param that, if set, indicates that the
136        port is the owner of the specified ranges (i.e., slave, default
137        responder, etc.).  If 'owner' is false, the interface is
138        interested in the specified ranges for snooping purposes.  If
139        an object wants to own some ranges and snoop on others, it will
140        need to use two different ports.
141    */
142    virtual void getDeviceAddressRanges(AddrRangeList &range_list,
143                                        bool &owner)
144    { panic("??"); }
145
146  public:
147
148    /** Function called by associated memory device (cache, memory, iodevice)
149        in order to send a timing request to the port.  Simply calls the peer
150        port receive function.
151        @return This function returns if the send was succesful in it's
152        recieve. If it was a failure, then the port will wait for a recvRetry
153        at which point it can issue a successful sendTiming.  This is used in
154        case a cache has a higher priority request come in while waiting for
155        the bus to arbitrate.
156    */
157    bool sendTiming(Packet &pkt) { return peer->recvTiming(pkt); }
158
159    /** Function called by the associated device to send an atomic access,
160        an access in which the data is moved and the state is updated in one
161        cycle, without interleaving with other memory accesses.
162    */
163    Tick sendAtomic(Packet &pkt)
164        { return peer->recvAtomic(pkt); }
165
166    /** Function called by the associated device to send a functional access,
167        an access in which the data is instantly updated everywhere in the
168        memory system, without affecting the current state of any block
169        or moving the block.
170    */
171    void sendFunctional(Packet &pkt)
172        { return peer->recvFunctional(pkt); }
173
174    /** Called by the associated device to send a status change to the device
175        connected to the peer interface.
176    */
177    void sendStatusChange(Status status) {peer->recvStatusChange(status); }
178
179    /** When a timing access doesn't return a success, some time later the
180        Retry will be sent.
181    */
182    Packet *sendRetry() { return peer->recvRetry(); }
183
184    /** Called by the associated device if it wishes to find out the blocksize
185        of the device on attached to the peer port.
186    */
187    int peerBlockSize() { return peer->deviceBlockSize(); }
188
189    /** Called by the associated device if it wishes to find out the address
190        ranges connected to the peer ports devices.
191    */
192    void getPeerAddressRanges(AddrRangeList &range_list, bool &owner)
193    { peer->getDeviceAddressRanges(range_list, owner); }
194
195    /** This function is a wrapper around sendFunctional()
196        that breaks a larger, arbitrarily aligned access into
197        appropriate chunks.  The default implementation can use
198        getBlockSize() to determine the block size and go from there.
199    */
200    virtual void readBlob(Addr addr, uint8_t *p, int size);
201
202    /** This function is a wrapper around sendFunctional()
203        that breaks a larger, arbitrarily aligned access into
204        appropriate chunks.  The default implementation can use
205        getBlockSize() to determine the block size and go from there.
206    */
207    virtual void writeBlob(Addr addr, uint8_t *p, int size);
208
209    /** Fill size bytes starting at addr with byte value val.  This
210        should not need to be virtual, since it can be implemented in
211        terms of writeBlob().  However, it shouldn't be
212        performance-critical either, so it could be if we wanted to.
213    */
214    virtual void memsetBlob(Addr addr, uint8_t val, int size);
215
216  private:
217
218    /** Internal helper function for read/writeBlob().
219     */
220    void blobHelper(Addr addr, uint8_t *p, int size, Command cmd);
221};
222
223#endif //__MEM_PORT_HH__
224