port.hh revision 2381 
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    /** Called to recive a timing call from the peer port. */
90    virtual SendResult recvTiming(Packet &pkt) = 0;
91
92    /** Virtual function that can be used to handle scheduling an event
93        to send the recvTiming at a given time.  This is for direct
94        connection without a interconnect.  The bus will override
95        this in it's port class because the bus does the timing.
96        This is used to insert timing when an interconnect doesn't
97        have it's own event queue.
98    */
99    virtual SendResult recvTiming(Packet &pkt, Tick t)
100    {
101        // schedule event to call recvTiming(pkt) @ tick t
102    }
103
104    /** Called to recive a atomic call from the peer port. */
105    virtual SendResult recvAtomic(Packet &pkt) = 0;
106
107    /** Called to recive a functional call from the peer port. */
108    virtual SendResult 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 recvBlockSizeQuery() { 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 recvAddressRangeQuery(std::list<Range<Addr> > &range_list,
136                                       bool &owner) = 0;
137
138  public:
139
140    /** Function called by associated memory device (cache, memory, iodevice)
141        in order to send a timing request to the port.  Simply calls the peer
142        port receive function.
143        @return This function returns if the send was succesful in it's
144        recieve. If it was a failure, then the port will wait for a recvRetry
145        at which point it can issue a successful sendTiming.  This is used in
146        case a cache has a higher priority request come in while waiting for
147        the bus to arbitrate.
148    */
149    SendResult sendTiming(Packet &pkt) { return peer->recvTiming(pkt); }
150
151    /** This function is identical to the sendTiming function, accept it
152        provides a time when the recvTiming should be called.  The
153        peer->recvTimimng will schedule the event, if it's device handles the
154        timing (bus) it will be overloaded by the bus type port to handle it
155        properly.
156    */
157    SendResult sendTiming(Packet &pkt, Tick t) { return peer->recvTiming(pkt, t); }
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    SendResult 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    SendResult 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 sendBlockSizeQuery() { return peer->recvBlockSizeQuery(); }
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 sendAddressRangesQuery(std::list<Range<Addr> > &range_list,
193                                bool &owner)
194    { peer->recvAddressRangesQuery(range_list, owner); }
195
196    // For the read/write blob functional
197    // This should be sufficient for everything except ProxyMemory
198    // which needs to slip a translation step in as well.  (Unless it
199    // does the translation underneath sendFunctional(), in which case
200    // maybe this doesn't need to be virtual at all.)  Do we need
201    // similar wrappers for sendAtomic()?  If not, should we drop the
202    // "Functional" from the names?
203
204    /** This function is a wrapper around sendFunctional()
205        that breaks a larger, arbitrarily aligned access into
206        appropriate chunks.  The default implementation can use
207        getBlockSize() to determine the block size and go from there.
208    */
209    virtual void readBlobFunctional(Addr addr, uint8_t *p, int size);
210
211    /** This function is a wrapper around sendFunctional()
212        that breaks a larger, arbitrarily aligned access into
213        appropriate chunks.  The default implementation can use
214        getBlockSize() to determine the block size and go from there.
215    */
216    virtual void writeBlobFunctional(Addr addr, const uint8_t *p, int size);
217
218    /** Fill size bytes starting at addr with byte value val.  This
219        should not need to be virtual, since it can be implemented in
220        terms of writeBlobFunctional().  However, it shouldn't be
221        performance-critical either, so it could be if we wanted to.
222        Not even sure if this is actually needed anywhere (there's a
223        prot_memset on the old functional memory that's never used),
224        but Nate claims it is.
225    */
226    void memsetBlobFunctional(Addr addr, uint8_t val, int size);
227
228    // I believe these two string functions can be defined once and
229    // for all at the top level by implementing them in terms of
230    // readBlob and writeBlob.
231
232    /** Write null-terminated string 'str' into memory at 'addr'. */
233    void writeStringFunctional(Addr addr, const char *str);
234
235    /** Read null-terminated string from 'addr' into 'str'. */
236    void readStringFunctional(std::string &str, Addr addr);
237};
238
239#endif //__MEM_PORT_HH__
240