port.hh revision 2406 
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/range.hh"
46#include "mem/packet.hh"
47#include "mem/request.hh"
48
49/**
50 * Ports are used to interface memory objects to
51 * each other.  They will always come in pairs, and we refer to the other
52 * port object as the peer.  These are used to make the design more
53 * modular so that a specific interface between every type of objcet doesn't
54 * have to be created.
55 *
56 * Recv accesor functions are being called from the peer interface.
57 * Send accessor functions are being called from the device the port is
58 * associated with, and it will call the peer recv. accessor function.
59 */
60class Port
61{
62  public:
63
64    // mey be better to use subclasses & RTTI?
65    /** Holds the ports status.  Keeps track if it is blocked, or has
66        calculated a range change. */
67    enum Status {
68        Blocked,
69        Unblocked,
70        RangeChange
71    };
72
73  private:
74
75    /** A pointer to the peer port.  Ports always come in pairs, that way they
76        can use a standardized interface to communicate between different
77        memory objects. */
78    Port *peer;
79
80  public:
81
82    /** Function to set the pointer for the peer port.
83        @todo should be called by the configuration stuff (python).
84    */
85    void setPeer(Port *port) { peer = port; }
86
87  protected:
88
89    /** These functions are protected because they should only be
90     * called by a peer port, never directly by any outside object. */
91
92    /** Called to recive a timing call from the peer port. */
93    virtual bool recvTiming(Packet &pkt) = 0;
94
95    /** Called to recive a atomic call from the peer port. */
96    virtual Tick recvAtomic(Packet &pkt) = 0;
97
98    /** Called to recive a functional call from the peer port. */
99    virtual void recvFunctional(Packet &pkt) = 0;
100
101    /** Called to recieve a status change from the peer port. */
102    virtual void recvStatusChange(Status status) = 0;
103
104    /** Called by a peer port if the send was unsuccesful, and had to
105        wait.  This shouldn't be valid for response paths (IO Devices).
106        so it is set to panic if it isn't already defined.
107    */
108    virtual Packet *recvRetry() { panic("??"); }
109
110    /** Called by a peer port in order to determine the block size of the
111        device connected to this port.  It sometimes doesn't make sense for
112        this function to be called, a DMA interface doesn't really have a
113        block size, so it is defaulted to a panic.
114    */
115    virtual int deviceBlockSize() { panic("??"); }
116
117    /** The peer port is requesting us to reply with a list of the ranges we
118        are responsible for.
119        @param owner is an output param that, if set, indicates that the
120        port is the owner of the specified ranges (i.e., slave, default
121        responder, etc.).  If 'owner' is false, the interface is
122        interested in the specified ranges for snooping purposes.  If
123        an object wants to own some ranges and snoop on others, it will
124        need to use two different ports.
125    */
126    virtual void recvAddressRangesQuery(std::list<Range<Addr> > &range_list,
127                                        bool &owner) { panic("??"); }
128
129  public:
130
131    /** Function called by associated memory device (cache, memory, iodevice)
132        in order to send a timing request to the port.  Simply calls the peer
133        port receive function.
134        @return This function returns if the send was succesful in it's
135        recieve. If it was a failure, then the port will wait for a recvRetry
136        at which point it can issue a successful sendTiming.  This is used in
137        case a cache has a higher priority request come in while waiting for
138        the bus to arbitrate.
139    */
140    bool sendTiming(Packet &pkt) { return peer->recvTiming(pkt); }
141
142    /** Function called by the associated device to send an atomic access,
143        an access in which the data is moved and the state is updated in one
144        cycle, without interleaving with other memory accesses.
145    */
146    Tick sendAtomic(Packet &pkt)
147        { return peer->recvAtomic(pkt); }
148
149    /** Function called by the associated device to send a functional access,
150        an access in which the data is instantly updated everywhere in the
151        memory system, without affecting the current state of any block
152        or moving the block.
153    */
154    void sendFunctional(Packet &pkt)
155        { return peer->recvFunctional(pkt); }
156
157    /** Called by the associated device to send a status change to the device
158        connected to the peer interface.
159    */
160    void sendStatusChange(Status status) {peer->recvStatusChange(status); }
161
162    /** When a timing access doesn't return a success, some time later the
163        Retry will be sent.
164    */
165    Packet *sendRetry() { return peer->recvRetry(); }
166
167    /** Called by the associated device if it wishes to find out the blocksize
168        of the device on attached to the peer port.
169    */
170    int peerBlockSize() { return peer->deviceBlockSize(); }
171
172    /** Called by the associated device if it wishes to find out the address
173        ranges connected to the peer ports devices.
174    */
175    void sendAddressRangesQuery(std::list<Range<Addr> > &range_list,
176                                bool &owner)
177    { peer->recvAddressRangesQuery(range_list, owner); }
178
179    // Do we need similar wrappers for sendAtomic()?  If not, should
180    // we drop the "Functional" from the names?
181
182    /** This function is a wrapper around sendFunctional()
183        that breaks a larger, arbitrarily aligned access into
184        appropriate chunks.  The default implementation can use
185        getBlockSize() to determine the block size and go from there.
186    */
187    void readBlobFunctional(Addr addr, uint8_t *p, int size);
188
189    /** This function is a wrapper around sendFunctional()
190        that breaks a larger, arbitrarily aligned access into
191        appropriate chunks.  The default implementation can use
192        getBlockSize() to determine the block size and go from there.
193    */
194    void writeBlobFunctional(Addr addr, uint8_t *p, int size);
195
196    /** Fill size bytes starting at addr with byte value val.  This
197        should not need to be virtual, since it can be implemented in
198        terms of writeBlobFunctional().  However, it shouldn't be
199        performance-critical either, so it could be if we wanted to.
200        Not even sure if this is actually needed anywhere (there's a
201        prot_memset on the old functional memory that's never used),
202        but Nate claims it is.
203    */
204    void memsetBlobFunctional(Addr addr, uint8_t val, int size);
205
206  private:
207
208    /** Internal helper function for read/writeBlob().
209     */
210    void blobHelper(Addr addr, uint8_t *p, int size, Command cmd);
211};
212
213#endif //__MEM_PORT_HH__
214