port.hh revision 2407 
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/** 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
56typedef std::list<Range<Addr> > AddrRangeList;
57
58/**
59 * Ports are used to interface memory objects to
60 * each other.  They will always come in pairs, and we refer to the other
61 * port object as the peer.  These are used to make the design more
62 * modular so that a specific interface between every type of objcet doesn't
63 * have to be created.
64 *
65 * Recv accesor functions are being called from the peer interface.
66 * Send accessor functions are being called from the device the port is
67 * associated with, and it will call the peer recv. accessor function.
68 */
69class Port
70{
71  public:
72
73    // mey be better to use subclasses & RTTI?
74    /** Holds the ports status.  Keeps track if it is blocked, or has
75        calculated a range change. */
76    enum Status {
77        Blocked,
78        Unblocked,
79        RangeChange
80    };
81
82  private:
83
84    /** A pointer to the peer port.  Ports always come in pairs, that way they
85        can use a standardized interface to communicate between different
86        memory objects. */
87    Port *peer;
88
89  public:
90
91    /** Function to set the pointer for the peer port.
92        @todo should be called by the configuration stuff (python).
93    */
94    void setPeer(Port *port) { peer = port; }
95
96  protected:
97
98    /** These functions are protected because they should only be
99     * called by a peer port, never directly by any outside object. */
100
101    /** Called to recive a timing call from the peer port. */
102    virtual bool recvTiming(Packet &pkt) = 0;
103
104    /** Called to recive a atomic call from the peer port. */
105    virtual Tick recvAtomic(Packet &pkt) = 0;
106
107    /** Called to recive a functional call from the peer port. */
108    virtual void recvFunctional(Packet &pkt) = 0;
109
110    /** Called to recieve a status change from the peer port. */
111    virtual void recvStatusChange(Status status) = 0;
112
113    /** Called by a peer port if the send was unsuccesful, and had to
114        wait.  This shouldn't be valid for response paths (IO Devices).
115        so it is set to panic if it isn't already defined.
116    */
117    virtual Packet *recvRetry() { panic("??"); }
118
119    /** Called by a peer port in order to determine the block size of the
120        device connected to this port.  It sometimes doesn't make sense for
121        this function to be called, a DMA interface doesn't really have a
122        block size, so it is defaulted to a panic.
123    */
124    virtual int deviceBlockSize() { panic("??"); }
125
126    /** The peer port is requesting us to reply with a list of the ranges we
127        are responsible for.
128        @param owner is an output param that, if set, indicates that the
129        port is the owner of the specified ranges (i.e., slave, default
130        responder, etc.).  If 'owner' is false, the interface is
131        interested in the specified ranges for snooping purposes.  If
132        an object wants to own some ranges and snoop on others, it will
133        need to use two different ports.
134    */
135    virtual void getDeviceAddressRanges(AddrRangeList &range_list,
136                                        bool &owner)
137    { panic("??"); }
138
139  public:
140
141    /** Function called by associated memory device (cache, memory, iodevice)
142        in order to send a timing request to the port.  Simply calls the peer
143        port receive function.
144        @return This function returns if the send was succesful in it's
145        recieve. If it was a failure, then the port will wait for a recvRetry
146        at which point it can issue a successful sendTiming.  This is used in
147        case a cache has a higher priority request come in while waiting for
148        the bus to arbitrate.
149    */
150    bool sendTiming(Packet &pkt) { return peer->recvTiming(pkt); }
151
152    /** Function called by the associated device to send an atomic access,
153        an access in which the data is moved and the state is updated in one
154        cycle, without interleaving with other memory accesses.
155    */
156    Tick sendAtomic(Packet &pkt)
157        { return peer->recvAtomic(pkt); }
158
159    /** Function called by the associated device to send a functional access,
160        an access in which the data is instantly updated everywhere in the
161        memory system, without affecting the current state of any block
162        or moving the block.
163    */
164    void sendFunctional(Packet &pkt)
165        { return peer->recvFunctional(pkt); }
166
167    /** Called by the associated device to send a status change to the device
168        connected to the peer interface.
169    */
170    void sendStatusChange(Status status) {peer->recvStatusChange(status); }
171
172    /** When a timing access doesn't return a success, some time later the
173        Retry will be sent.
174    */
175    Packet *sendRetry() { return peer->recvRetry(); }
176
177    /** Called by the associated device if it wishes to find out the blocksize
178        of the device on attached to the peer port.
179    */
180    int peerBlockSize() { return peer->deviceBlockSize(); }
181
182    /** Called by the associated device if it wishes to find out the address
183        ranges connected to the peer ports devices.
184    */
185    void getPeerAddressRanges(AddrRangeList &range_list, bool &owner)
186    { peer->getDeviceAddressRanges(range_list, owner); }
187
188    // Do we need similar wrappers for sendAtomic()?  If not, should
189    // we drop the "Functional" from the names?
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    void readBlobFunctional(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    void writeBlobFunctional(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 writeBlobFunctional().  However, it shouldn't be
208        performance-critical either, so it could be if we wanted to.
209        Not even sure if this is actually needed anywhere (there's a
210        prot_memset on the old functional memory that's never used),
211        but Nate claims it is.
212    */
213    void memsetBlobFunctional(Addr addr, uint8_t val, int size);
214
215  private:
216
217    /** Internal helper function for read/writeBlob().
218     */
219    void blobHelper(Addr addr, uint8_t *p, int size, Command cmd);
220};
221
222#endif //__MEM_PORT_HH__
223