1/*
2 * Copyright (c) 2011-2012 ARM Limited
3 * All rights reserved
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder. You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2002-2005 The Regents of The University of Michigan
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Ron Dreslinski
41 * Andreas Hansson
42 * William Wang
43 */
44
45/**
46 * @file
47 * Port Object Declaration.
48 */
49
50#ifndef __MEM_PORT_HH__
51#define __MEM_PORT_HH__
52
53#include <list>
54
55#include "base/range.hh"
56#include "mem/packet.hh"
57
58/**
59 * This typedef is used to clean up getAddrRanges(). It's declared
60 * outside the Port object since it's also used by some mem objects.
61 * Eventually we should move this typedef to wherever Addr is
62 * defined.
63 */
64
65typedef std::list<Range<Addr> > AddrRangeList;
66typedef std::list<Range<Addr> >::iterator AddrRangeIter;
67
68class MemObject;
69
70/**
71 * Ports are used to interface memory objects to each other. A port is
72 * either a master or a slave and the connected peer is always of the
73 * opposite role.
74 *
75 * Each port has a name and an owner, and enables three basic types of
76 * accesses to the peer port: functional, atomic and timing.
77 */
78class Port
79{
80
81 private:
82
83 /** Descriptive name (for DPRINTF output) */
84 std::string portName;
85
86 protected:
87
88 /**
89 * A numeric identifier to distinguish ports in a vector, and set
90 * to InvalidPortID in case this port is not part of a vector.
91 */
92 const PortID id;
93
94 /** A pointer to the peer port. */
95 Port* peer;
96
97 /** A reference to the MemObject that owns this port. */
98 MemObject& owner;
99
100 /**
101 * Abstract base class for ports
102 *
103 * @param _name Port name including the owners name
104 * @param _owner The MemObject that is the structural owner of this port
105 * @param _id A port identifier for vector ports
106 */
107 Port(const std::string& _name, MemObject& _owner, PortID _id);
108
109 /**
110 * Virtual destructor due to inheritance.
111 */
112 virtual ~Port();
113
114 public:
115
116 /** Return port name (for DPRINTF). */
117 const std::string name() const { return portName; }
118
119 /** Get the port id. */
120 PortID getId() const { return id; }
121
122 protected:
123
124 /**
125 * Called by a peer port if sendTimingReq, sendTimingResp or
126 * sendTimingSnoopResp was unsuccesful, and had to wait.
127 */
128 virtual void recvRetry() = 0;
129
130 public:
131
132 /**
133 * Send a retry to a peer port that previously attempted a
134 * sendTimingReq, sendTimingResp or sendTimingSnoopResp which was
135 * unsuccessful.
136 */
137 void sendRetry() { return peer->recvRetry(); }
138
139};
140
141/** Forward declaration */
142class SlavePort;
143
144/**
145 * A MasterPort is a specialisation of a port. In addition to the
146 * basic functionality of sending packets to its slave peer, it also
147 * has functions specific to a master, e.g. to receive range changes
148 * or determine if the port is snooping or not.
149 */
150class MasterPort : public Port
151{
152
153 friend class SlavePort;
154
155 private:
156
157 SlavePort* _slavePort;
158
159 public:
160
161 MasterPort(const std::string& name, MemObject* owner,
162 PortID id = InvalidPortID);
163 virtual ~MasterPort();
164
165 void bind(SlavePort& slave_port);
166 SlavePort& getSlavePort() const;
167 bool isConnected() const;
168
169 /**
170 * Send an atomic request packet, where the data is moved and the
171 * state is updated in zero time, without interleaving with other
172 * memory accesses.
173 *
174 * @param pkt Packet to send.
175 *
176 * @return Estimated latency of access.
177 */
178 Tick sendAtomic(PacketPtr pkt);
179
180 /**
181 * Send a functional request packet, where the data is instantly
182 * updated everywhere in the memory system, without affecting the
183 * current state of any block or moving the block.
184 *
185 * @param pkt Packet to send.
186 */
187 void sendFunctional(PacketPtr pkt);
188
189 /**
190 * Attempt to send a timing request to the slave port by calling
191 * its corresponding receive function. If the send does not
192 * succeed, as indicated by the return value, then the sender must
193 * wait for a recvRetry at which point it can re-issue a
194 * sendTimingReq.
195 *
196 * @param pkt Packet to send.
197 *
198 * @return If the send was succesful or not.
199 */
200 bool sendTimingReq(PacketPtr pkt);
201
202 /**
203 * Attempt to send a timing snoop response packet to the slave
204 * port by calling its corresponding receive function. If the send
205 * does not succeed, as indicated by the return value, then the
206 * sender must wait for a recvRetry at which point it can re-issue
207 * a sendTimingSnoopResp.
208 *
209 * @param pkt Packet to send.
210 */
211 bool sendTimingSnoopResp(PacketPtr pkt);
212
213 /**
214 * Determine if this master port is snooping or not. The default
215 * implementation returns false and thus tells the neighbour we
216 * are not snooping. Any master port that wants to receive snoop
217 * requests (e.g. a cache connected to a bus) has to override this
218 * function.
219 *
220 * @return true if the port should be considered a snooper
221 */
222 virtual bool isSnooping() const { return false; }
223
224 /**
225 * Called by a peer port in order to determine the block size of
226 * the owner of this port.
227 */
228 virtual unsigned deviceBlockSize() const { return 0; }
229
230 /** Called by the associated device if it wishes to find out the blocksize
231 of the device on attached to the peer port.
232 */
233 unsigned peerBlockSize() const;
234
235 /** Inject a PrintReq for the given address to print the state of
236 * that address throughout the memory system. For debugging.
237 */
238 void printAddr(Addr a);
239
240 protected:
241
242 /**
243 * Receive an atomic snoop request packet from the slave port.
244 */
245 virtual Tick recvAtomicSnoop(PacketPtr pkt)
246 {
247 panic("%s was not expecting an atomic snoop request\n", name());
248 return 0;
249 }
250
251 /**
252 * Receive a functional snoop request packet from the slave port.
253 */
254 virtual void recvFunctionalSnoop(PacketPtr pkt)
255 {
256 panic("%s was not expecting a functional snoop request\n", name());
257 }
258
259 /**
260 * Receive a timing response from the slave port.
261 */
262 virtual bool recvTimingResp(PacketPtr pkt) = 0;
263
264 /**
265 * Receive a timing snoop request from the slave port.
266 */
267 virtual void recvTimingSnoopReq(PacketPtr pkt)
268 {
269 panic("%s was not expecting a timing snoop request\n", name());
270 }
271
272 /**
273 * Called to receive an address range change from the peer slave
274 * port. the default implementation ignored the change and does
275 * nothing. Override this function in a derived class if the owner
276 * needs to be aware of he laesddress ranges, e.g. in an
277 * interconnect component like a bus.
278 */
279 virtual void recvRangeChange() { }
280};
281
282/**
283 * A SlavePort is a specialisation of a port. In addition to the
284 * basic functionality of sending packets to its master peer, it also
285 * has functions specific to a slave, e.g. to send range changes
286 * and get the address ranges that the port responds to.
287 */
288class SlavePort : public Port
289{
290
291 friend class MasterPort;
292
293 private:
294
295 MasterPort* _masterPort;
296
297 public:
298
299 SlavePort(const std::string& name, MemObject* owner,
300 PortID id = InvalidPortID);
301 virtual ~SlavePort();
302
303 void bind(MasterPort& master_port);
304 MasterPort& getMasterPort() const;
305 bool isConnected() const;
306
307 /**
308 * Send an atomic snoop request packet, where the data is moved
309 * and the state is updated in zero time, without interleaving
310 * with other memory accesses.
311 *
312 * @param pkt Snoop packet to send.
313 *
314 * @return Estimated latency of access.
315 */
316 Tick sendAtomicSnoop(PacketPtr pkt);
317
318 /**
319 * Send a functional snoop request packet, where the data is
320 * instantly updated everywhere in the memory system, without
321 * affecting the current state of any block or moving the block.
322 *
323 * @param pkt Snoop packet to send.
324 */
325 void sendFunctionalSnoop(PacketPtr pkt);
326
327 /**
328 * Attempt to send a timing response to the master port by calling
329 * its corresponding receive function. If the send does not
330 * succeed, as indicated by the return value, then the sender must
331 * wait for a recvRetry at which point it can re-issue a
332 * sendTimingResp.
333 *
334 * @param pkt Packet to send.
335 *
336 * @return If the send was succesful or not.
337 */
338 bool sendTimingResp(PacketPtr pkt);
339
340 /**
341 * Attempt to send a timing snoop request packet to the master port
342 * by calling its corresponding receive function. Snoop requests
343 * always succeed and hence no return value is needed.
344 *
345 * @param pkt Packet to send.
346 */
347 void sendTimingSnoopReq(PacketPtr pkt);
348
349 /**
350 * Called by a peer port in order to determine the block size of
351 * the owner of this port.
352 */
353 virtual unsigned deviceBlockSize() const { return 0; }
354
355 /** Called by the associated device if it wishes to find out the blocksize
356 of the device on attached to the peer port.
357 */
358 unsigned peerBlockSize() const;
359
360 /**
361 * Called by the owner to send a range change
362 */
363 void sendRangeChange() const { _masterPort->recvRangeChange(); }
364
365 /**
366 * Get a list of the non-overlapping address ranges the owner is
367 * responsible for. All slave ports must override this function
368 * and return a populated list with at least one item.
369 *
370 * @return a list of ranges responded to
371 */
372 virtual AddrRangeList getAddrRanges() = 0;
373
374 protected:
375
376 /**
377 * Receive an atomic request packet from the master port.
378 */
379 virtual Tick recvAtomic(PacketPtr pkt) = 0;
380
381 /**
382 * Receive a functional request packet from the master port.
383 */
384 virtual void recvFunctional(PacketPtr pkt) = 0;
385
386 /**
387 * Receive a timing request from the master port.
388 */
389 virtual bool recvTimingReq(PacketPtr pkt) = 0;
390
391 /**
392 * Receive a timing snoop response from the master port.
393 */
394 virtual bool recvTimingSnoopResp(PacketPtr pkt)
395 {
396 panic("%s was not expecting a timing snoop response\n", name());
397 }
398
399};
400
401#endif //__MEM_PORT_HH__