1/*
2 * Copyright (c) 2011-2015, 2017 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 * Ali Saidi
42 * Andreas Hansson
43 * William Wang
44 */
45
46/**
47 * @file
48 * Declaration of a coherent crossbar.
49 */
50
51#ifndef __MEM_COHERENT_XBAR_HH__
52#define __MEM_COHERENT_XBAR_HH__
53
| 1/*
2 * Copyright (c) 2011-2015, 2017 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 * Ali Saidi
42 * Andreas Hansson
43 * William Wang
44 */
45
46/**
47 * @file
48 * Declaration of a coherent crossbar.
49 */
50
51#ifndef __MEM_COHERENT_XBAR_HH__
52#define __MEM_COHERENT_XBAR_HH__
53
|
| 54#include <unordered_map>
|
54#include <unordered_set>
55
56#include "mem/snoop_filter.hh"
57#include "mem/xbar.hh"
58#include "params/CoherentXBar.hh"
59
60/**
61 * A coherent crossbar connects a number of (potentially) snooping
62 * masters and slaves, and routes the request and response packets
63 * based on the address, and also forwards all requests to the
64 * snoopers and deals with the snoop responses.
65 *
66 * The coherent crossbar can be used as a template for modelling QPI,
67 * HyperTransport, ACE and coherent OCP buses, and is typically used
68 * for the L1-to-L2 buses and as the main system interconnect. @sa
69 * \ref gem5MemorySystem "gem5 Memory System"
70 */
71class CoherentXBar : public BaseXBar
72{
73
74 protected:
75
76 /**
77 * Declare the layers of this crossbar, one vector for requests,
78 * one for responses, and one for snoop responses
79 */
80 std::vector<ReqLayer*> reqLayers;
81 std::vector<RespLayer*> respLayers;
82 std::vector<SnoopRespLayer*> snoopLayers;
83
84 /**
85 * Declaration of the coherent crossbar slave port type, one will
86 * be instantiated for each of the master ports connecting to the
87 * crossbar.
88 */
89 class CoherentXBarSlavePort : public QueuedSlavePort
90 {
91
92 private:
93
94 /** A reference to the crossbar to which this port belongs. */
95 CoherentXBar &xbar;
96
97 /** A normal packet queue used to store responses. */
98 RespPacketQueue queue;
99
100 public:
101
102 CoherentXBarSlavePort(const std::string &_name,
103 CoherentXBar &_xbar, PortID _id)
104 : QueuedSlavePort(_name, &_xbar, queue, _id), xbar(_xbar),
105 queue(_xbar, *this)
106 { }
107
108 protected:
109
110 /**
111 * When receiving a timing request, pass it to the crossbar.
112 */
113 virtual bool recvTimingReq(PacketPtr pkt)
114 { return xbar.recvTimingReq(pkt, id); }
115
116 /**
117 * When receiving a timing snoop response, pass it to the crossbar.
118 */
119 virtual bool recvTimingSnoopResp(PacketPtr pkt)
120 { return xbar.recvTimingSnoopResp(pkt, id); }
121
122 /**
123 * When receiving an atomic request, pass it to the crossbar.
124 */
125 virtual Tick recvAtomic(PacketPtr pkt)
126 { return xbar.recvAtomic(pkt, id); }
127
128 /**
129 * When receiving a functional request, pass it to the crossbar.
130 */
131 virtual void recvFunctional(PacketPtr pkt)
132 { xbar.recvFunctional(pkt, id); }
133
134 /**
135 * Return the union of all adress ranges seen by this crossbar.
136 */
137 virtual AddrRangeList getAddrRanges() const
138 { return xbar.getAddrRanges(); }
139
140 };
141
142 /**
143 * Declaration of the coherent crossbar master port type, one will be
144 * instantiated for each of the slave interfaces connecting to the
145 * crossbar.
146 */
147 class CoherentXBarMasterPort : public MasterPort
148 {
149 private:
150 /** A reference to the crossbar to which this port belongs. */
151 CoherentXBar &xbar;
152
153 public:
154
155 CoherentXBarMasterPort(const std::string &_name,
156 CoherentXBar &_xbar, PortID _id)
157 : MasterPort(_name, &_xbar, _id), xbar(_xbar)
158 { }
159
160 protected:
161
162 /**
163 * Determine if this port should be considered a snooper. For
164 * a coherent crossbar master port this is always true.
165 *
166 * @return a boolean that is true if this port is snooping
167 */
168 virtual bool isSnooping() const
169 { return true; }
170
171 /**
172 * When receiving a timing response, pass it to the crossbar.
173 */
174 virtual bool recvTimingResp(PacketPtr pkt)
175 { return xbar.recvTimingResp(pkt, id); }
176
177 /**
178 * When receiving a timing snoop request, pass it to the crossbar.
179 */
180 virtual void recvTimingSnoopReq(PacketPtr pkt)
181 { return xbar.recvTimingSnoopReq(pkt, id); }
182
183 /**
184 * When receiving an atomic snoop request, pass it to the crossbar.
185 */
186 virtual Tick recvAtomicSnoop(PacketPtr pkt)
187 { return xbar.recvAtomicSnoop(pkt, id); }
188
189 /**
190 * When receiving a functional snoop request, pass it to the crossbar.
191 */
192 virtual void recvFunctionalSnoop(PacketPtr pkt)
193 { xbar.recvFunctionalSnoop(pkt, id); }
194
195 /** When reciving a range change from the peer port (at id),
196 pass it to the crossbar. */
197 virtual void recvRangeChange()
198 { xbar.recvRangeChange(id); }
199
200 /** When reciving a retry from the peer port (at id),
201 pass it to the crossbar. */
202 virtual void recvReqRetry()
203 { xbar.recvReqRetry(id); }
204
205 };
206
207 /**
208 * Internal class to bridge between an incoming snoop response
209 * from a slave port and forwarding it through an outgoing slave
210 * port. It is effectively a dangling master port.
211 */
212 class SnoopRespPort : public MasterPort
213 {
214
215 private:
216
217 /** The port which we mirror internally. */
218 QueuedSlavePort& slavePort;
219
220 public:
221
222 /**
223 * Create a snoop response port that mirrors a given slave port.
224 */
225 SnoopRespPort(QueuedSlavePort& slave_port, CoherentXBar& _xbar) :
226 MasterPort(slave_port.name() + ".snoopRespPort", &_xbar),
227 slavePort(slave_port) { }
228
229 /**
230 * Override the sending of retries and pass them on through
231 * the mirrored slave port.
232 */
233 void sendRetryResp() {
234 // forward it as a snoop response retry
235 slavePort.sendRetrySnoopResp();
236 }
237
238 /**
239 * Provided as necessary.
240 */
241 void recvReqRetry() { panic("SnoopRespPort should never see retry\n"); }
242
243 /**
244 * Provided as necessary.
245 */
246 bool recvTimingResp(PacketPtr pkt)
247 {
248 panic("SnoopRespPort should never see timing response\n");
249 return false;
250 }
251
252 };
253
254 std::vector<SnoopRespPort*> snoopRespPorts;
255
256 std::vector<QueuedSlavePort*> snoopPorts;
257
258 /**
259 * Store the outstanding requests that we are expecting snoop
260 * responses from so we can determine which snoop responses we
261 * generated and which ones were merely forwarded.
262 */
263 std::unordered_set<RequestPtr> outstandingSnoop;
264
265 /**
| 55#include <unordered_set>
56
57#include "mem/snoop_filter.hh"
58#include "mem/xbar.hh"
59#include "params/CoherentXBar.hh"
60
61/**
62 * A coherent crossbar connects a number of (potentially) snooping
63 * masters and slaves, and routes the request and response packets
64 * based on the address, and also forwards all requests to the
65 * snoopers and deals with the snoop responses.
66 *
67 * The coherent crossbar can be used as a template for modelling QPI,
68 * HyperTransport, ACE and coherent OCP buses, and is typically used
69 * for the L1-to-L2 buses and as the main system interconnect. @sa
70 * \ref gem5MemorySystem "gem5 Memory System"
71 */
72class CoherentXBar : public BaseXBar
73{
74
75 protected:
76
77 /**
78 * Declare the layers of this crossbar, one vector for requests,
79 * one for responses, and one for snoop responses
80 */
81 std::vector<ReqLayer*> reqLayers;
82 std::vector<RespLayer*> respLayers;
83 std::vector<SnoopRespLayer*> snoopLayers;
84
85 /**
86 * Declaration of the coherent crossbar slave port type, one will
87 * be instantiated for each of the master ports connecting to the
88 * crossbar.
89 */
90 class CoherentXBarSlavePort : public QueuedSlavePort
91 {
92
93 private:
94
95 /** A reference to the crossbar to which this port belongs. */
96 CoherentXBar &xbar;
97
98 /** A normal packet queue used to store responses. */
99 RespPacketQueue queue;
100
101 public:
102
103 CoherentXBarSlavePort(const std::string &_name,
104 CoherentXBar &_xbar, PortID _id)
105 : QueuedSlavePort(_name, &_xbar, queue, _id), xbar(_xbar),
106 queue(_xbar, *this)
107 { }
108
109 protected:
110
111 /**
112 * When receiving a timing request, pass it to the crossbar.
113 */
114 virtual bool recvTimingReq(PacketPtr pkt)
115 { return xbar.recvTimingReq(pkt, id); }
116
117 /**
118 * When receiving a timing snoop response, pass it to the crossbar.
119 */
120 virtual bool recvTimingSnoopResp(PacketPtr pkt)
121 { return xbar.recvTimingSnoopResp(pkt, id); }
122
123 /**
124 * When receiving an atomic request, pass it to the crossbar.
125 */
126 virtual Tick recvAtomic(PacketPtr pkt)
127 { return xbar.recvAtomic(pkt, id); }
128
129 /**
130 * When receiving a functional request, pass it to the crossbar.
131 */
132 virtual void recvFunctional(PacketPtr pkt)
133 { xbar.recvFunctional(pkt, id); }
134
135 /**
136 * Return the union of all adress ranges seen by this crossbar.
137 */
138 virtual AddrRangeList getAddrRanges() const
139 { return xbar.getAddrRanges(); }
140
141 };
142
143 /**
144 * Declaration of the coherent crossbar master port type, one will be
145 * instantiated for each of the slave interfaces connecting to the
146 * crossbar.
147 */
148 class CoherentXBarMasterPort : public MasterPort
149 {
150 private:
151 /** A reference to the crossbar to which this port belongs. */
152 CoherentXBar &xbar;
153
154 public:
155
156 CoherentXBarMasterPort(const std::string &_name,
157 CoherentXBar &_xbar, PortID _id)
158 : MasterPort(_name, &_xbar, _id), xbar(_xbar)
159 { }
160
161 protected:
162
163 /**
164 * Determine if this port should be considered a snooper. For
165 * a coherent crossbar master port this is always true.
166 *
167 * @return a boolean that is true if this port is snooping
168 */
169 virtual bool isSnooping() const
170 { return true; }
171
172 /**
173 * When receiving a timing response, pass it to the crossbar.
174 */
175 virtual bool recvTimingResp(PacketPtr pkt)
176 { return xbar.recvTimingResp(pkt, id); }
177
178 /**
179 * When receiving a timing snoop request, pass it to the crossbar.
180 */
181 virtual void recvTimingSnoopReq(PacketPtr pkt)
182 { return xbar.recvTimingSnoopReq(pkt, id); }
183
184 /**
185 * When receiving an atomic snoop request, pass it to the crossbar.
186 */
187 virtual Tick recvAtomicSnoop(PacketPtr pkt)
188 { return xbar.recvAtomicSnoop(pkt, id); }
189
190 /**
191 * When receiving a functional snoop request, pass it to the crossbar.
192 */
193 virtual void recvFunctionalSnoop(PacketPtr pkt)
194 { xbar.recvFunctionalSnoop(pkt, id); }
195
196 /** When reciving a range change from the peer port (at id),
197 pass it to the crossbar. */
198 virtual void recvRangeChange()
199 { xbar.recvRangeChange(id); }
200
201 /** When reciving a retry from the peer port (at id),
202 pass it to the crossbar. */
203 virtual void recvReqRetry()
204 { xbar.recvReqRetry(id); }
205
206 };
207
208 /**
209 * Internal class to bridge between an incoming snoop response
210 * from a slave port and forwarding it through an outgoing slave
211 * port. It is effectively a dangling master port.
212 */
213 class SnoopRespPort : public MasterPort
214 {
215
216 private:
217
218 /** The port which we mirror internally. */
219 QueuedSlavePort& slavePort;
220
221 public:
222
223 /**
224 * Create a snoop response port that mirrors a given slave port.
225 */
226 SnoopRespPort(QueuedSlavePort& slave_port, CoherentXBar& _xbar) :
227 MasterPort(slave_port.name() + ".snoopRespPort", &_xbar),
228 slavePort(slave_port) { }
229
230 /**
231 * Override the sending of retries and pass them on through
232 * the mirrored slave port.
233 */
234 void sendRetryResp() {
235 // forward it as a snoop response retry
236 slavePort.sendRetrySnoopResp();
237 }
238
239 /**
240 * Provided as necessary.
241 */
242 void recvReqRetry() { panic("SnoopRespPort should never see retry\n"); }
243
244 /**
245 * Provided as necessary.
246 */
247 bool recvTimingResp(PacketPtr pkt)
248 {
249 panic("SnoopRespPort should never see timing response\n");
250 return false;
251 }
252
253 };
254
255 std::vector<SnoopRespPort*> snoopRespPorts;
256
257 std::vector<QueuedSlavePort*> snoopPorts;
258
259 /**
260 * Store the outstanding requests that we are expecting snoop
261 * responses from so we can determine which snoop responses we
262 * generated and which ones were merely forwarded.
263 */
264 std::unordered_set<RequestPtr> outstandingSnoop;
265
266 /**
|
| 267 * Store the outstanding cache maintenance that we are expecting
268 * snoop responses from so we can determine when we received all
269 * snoop responses and if any of the agents satisfied the request.
270 */
271 std::unordered_map<PacketId, PacketPtr> outstandingCMO;
272
273 /**
|
266 * Keep a pointer to the system to be allow to querying memory system
267 * properties.
268 */
269 System *system;
270
271 /** A snoop filter that tracks cache line residency and can restrict the
272 * broadcast needed for probes. NULL denotes an absent filter. */
273 SnoopFilter *snoopFilter;
274
275 /** Cycles of snoop response latency.*/
276 const Cycles snoopResponseLatency;
277
278 /** Is this crossbar the point of coherency? **/
279 const bool pointOfCoherency;
280
281 /** Is this crossbar the point of unification? **/
282 const bool pointOfUnification;
283
284 /**
285 * Upstream caches need this packet until true is returned, so
286 * hold it for deletion until a subsequent call
287 */
288 std::unique_ptr<Packet> pendingDelete;
289
290 /** Function called by the port when the crossbar is recieving a Timing
291 request packet.*/
292 bool recvTimingReq(PacketPtr pkt, PortID slave_port_id);
293
294 /** Function called by the port when the crossbar is recieving a Timing
295 response packet.*/
296 bool recvTimingResp(PacketPtr pkt, PortID master_port_id);
297
298 /** Function called by the port when the crossbar is recieving a timing
299 snoop request.*/
300 void recvTimingSnoopReq(PacketPtr pkt, PortID master_port_id);
301
302 /** Function called by the port when the crossbar is recieving a timing
303 snoop response.*/
304 bool recvTimingSnoopResp(PacketPtr pkt, PortID slave_port_id);
305
306 /** Timing function called by port when it is once again able to process
307 * requests. */
308 void recvReqRetry(PortID master_port_id);
309
310 /**
311 * Forward a timing packet to our snoopers, potentially excluding
312 * one of the connected coherent masters to avoid sending a packet
313 * back to where it came from.
314 *
315 * @param pkt Packet to forward
316 * @param exclude_slave_port_id Id of slave port to exclude
317 */
318 void forwardTiming(PacketPtr pkt, PortID exclude_slave_port_id) {
319 forwardTiming(pkt, exclude_slave_port_id, snoopPorts);
320 }
321
322 /**
323 * Forward a timing packet to a selected list of snoopers, potentially
324 * excluding one of the connected coherent masters to avoid sending a packet
325 * back to where it came from.
326 *
327 * @param pkt Packet to forward
328 * @param exclude_slave_port_id Id of slave port to exclude
329 * @param dests Vector of destination ports for the forwarded pkt
330 */
331 void forwardTiming(PacketPtr pkt, PortID exclude_slave_port_id,
332 const std::vector<QueuedSlavePort*>& dests);
333
334 /** Function called by the port when the crossbar is recieving a Atomic
335 transaction.*/
336 Tick recvAtomic(PacketPtr pkt, PortID slave_port_id);
337
338 /** Function called by the port when the crossbar is recieving an
339 atomic snoop transaction.*/
340 Tick recvAtomicSnoop(PacketPtr pkt, PortID master_port_id);
341
342 /**
343 * Forward an atomic packet to our snoopers, potentially excluding
344 * one of the connected coherent masters to avoid sending a packet
345 * back to where it came from.
346 *
347 * @param pkt Packet to forward
348 * @param exclude_slave_port_id Id of slave port to exclude
349 *
350 * @return a pair containing the snoop response and snoop latency
351 */
352 std::pair<MemCmd, Tick> forwardAtomic(PacketPtr pkt,
353 PortID exclude_slave_port_id)
354 {
355 return forwardAtomic(pkt, exclude_slave_port_id, InvalidPortID,
356 snoopPorts);
357 }
358
359 /**
360 * Forward an atomic packet to a selected list of snoopers, potentially
361 * excluding one of the connected coherent masters to avoid sending a packet
362 * back to where it came from.
363 *
364 * @param pkt Packet to forward
365 * @param exclude_slave_port_id Id of slave port to exclude
366 * @param source_master_port_id Id of the master port for snoops from below
367 * @param dests Vector of destination ports for the forwarded pkt
368 *
369 * @return a pair containing the snoop response and snoop latency
370 */
371 std::pair<MemCmd, Tick> forwardAtomic(PacketPtr pkt,
372 PortID exclude_slave_port_id,
373 PortID source_master_port_id,
374 const std::vector<QueuedSlavePort*>&
375 dests);
376
377 /** Function called by the port when the crossbar is recieving a Functional
378 transaction.*/
379 void recvFunctional(PacketPtr pkt, PortID slave_port_id);
380
381 /** Function called by the port when the crossbar is recieving a functional
382 snoop transaction.*/
383 void recvFunctionalSnoop(PacketPtr pkt, PortID master_port_id);
384
385 /**
386 * Forward a functional packet to our snoopers, potentially
387 * excluding one of the connected coherent masters to avoid
388 * sending a packet back to where it came from.
389 *
390 * @param pkt Packet to forward
391 * @param exclude_slave_port_id Id of slave port to exclude
392 */
393 void forwardFunctional(PacketPtr pkt, PortID exclude_slave_port_id);
394
395 /**
396 * Determine if the crossbar should sink the packet, as opposed to
397 * forwarding it, or responding.
398 */
399 bool sinkPacket(const PacketPtr pkt) const;
400
401 /**
402 * Determine if the crossbar should forward the packet, as opposed to
403 * responding to it.
404 */
405 bool forwardPacket(const PacketPtr pkt);
406
407 /**
408 * Determine if the packet's destination is the memory below
409 *
410 * The memory below is the destination for a cache mainteance
411 * operation to the Point of Coherence/Unification if this is the
412 * Point of Coherence/Unification.
413 *
414 * @param pkt The processed packet
415 *
416 * @return Whether the memory below is the destination for the packet
417 */
418 bool isDestination(const PacketPtr pkt) const
419 {
420 return (pkt->req->isToPOC() && pointOfCoherency) ||
421 (pkt->req->isToPOU() && pointOfUnification);
422 }
423
424 Stats::Scalar snoops;
425 Stats::Scalar snoopTraffic;
426 Stats::Distribution snoopFanout;
427
428 public:
429
430 virtual void init();
431
432 CoherentXBar(const CoherentXBarParams *p);
433
434 virtual ~CoherentXBar();
435
436 virtual void regStats();
437};
438
439#endif //__MEM_COHERENT_XBAR_HH__
| 274 * Keep a pointer to the system to be allow to querying memory system
275 * properties.
276 */
277 System *system;
278
279 /** A snoop filter that tracks cache line residency and can restrict the
280 * broadcast needed for probes. NULL denotes an absent filter. */
281 SnoopFilter *snoopFilter;
282
283 /** Cycles of snoop response latency.*/
284 const Cycles snoopResponseLatency;
285
286 /** Is this crossbar the point of coherency? **/
287 const bool pointOfCoherency;
288
289 /** Is this crossbar the point of unification? **/
290 const bool pointOfUnification;
291
292 /**
293 * Upstream caches need this packet until true is returned, so
294 * hold it for deletion until a subsequent call
295 */
296 std::unique_ptr<Packet> pendingDelete;
297
298 /** Function called by the port when the crossbar is recieving a Timing
299 request packet.*/
300 bool recvTimingReq(PacketPtr pkt, PortID slave_port_id);
301
302 /** Function called by the port when the crossbar is recieving a Timing
303 response packet.*/
304 bool recvTimingResp(PacketPtr pkt, PortID master_port_id);
305
306 /** Function called by the port when the crossbar is recieving a timing
307 snoop request.*/
308 void recvTimingSnoopReq(PacketPtr pkt, PortID master_port_id);
309
310 /** Function called by the port when the crossbar is recieving a timing
311 snoop response.*/
312 bool recvTimingSnoopResp(PacketPtr pkt, PortID slave_port_id);
313
314 /** Timing function called by port when it is once again able to process
315 * requests. */
316 void recvReqRetry(PortID master_port_id);
317
318 /**
319 * Forward a timing packet to our snoopers, potentially excluding
320 * one of the connected coherent masters to avoid sending a packet
321 * back to where it came from.
322 *
323 * @param pkt Packet to forward
324 * @param exclude_slave_port_id Id of slave port to exclude
325 */
326 void forwardTiming(PacketPtr pkt, PortID exclude_slave_port_id) {
327 forwardTiming(pkt, exclude_slave_port_id, snoopPorts);
328 }
329
330 /**
331 * Forward a timing packet to a selected list of snoopers, potentially
332 * excluding one of the connected coherent masters to avoid sending a packet
333 * back to where it came from.
334 *
335 * @param pkt Packet to forward
336 * @param exclude_slave_port_id Id of slave port to exclude
337 * @param dests Vector of destination ports for the forwarded pkt
338 */
339 void forwardTiming(PacketPtr pkt, PortID exclude_slave_port_id,
340 const std::vector<QueuedSlavePort*>& dests);
341
342 /** Function called by the port when the crossbar is recieving a Atomic
343 transaction.*/
344 Tick recvAtomic(PacketPtr pkt, PortID slave_port_id);
345
346 /** Function called by the port when the crossbar is recieving an
347 atomic snoop transaction.*/
348 Tick recvAtomicSnoop(PacketPtr pkt, PortID master_port_id);
349
350 /**
351 * Forward an atomic packet to our snoopers, potentially excluding
352 * one of the connected coherent masters to avoid sending a packet
353 * back to where it came from.
354 *
355 * @param pkt Packet to forward
356 * @param exclude_slave_port_id Id of slave port to exclude
357 *
358 * @return a pair containing the snoop response and snoop latency
359 */
360 std::pair<MemCmd, Tick> forwardAtomic(PacketPtr pkt,
361 PortID exclude_slave_port_id)
362 {
363 return forwardAtomic(pkt, exclude_slave_port_id, InvalidPortID,
364 snoopPorts);
365 }
366
367 /**
368 * Forward an atomic packet to a selected list of snoopers, potentially
369 * excluding one of the connected coherent masters to avoid sending a packet
370 * back to where it came from.
371 *
372 * @param pkt Packet to forward
373 * @param exclude_slave_port_id Id of slave port to exclude
374 * @param source_master_port_id Id of the master port for snoops from below
375 * @param dests Vector of destination ports for the forwarded pkt
376 *
377 * @return a pair containing the snoop response and snoop latency
378 */
379 std::pair<MemCmd, Tick> forwardAtomic(PacketPtr pkt,
380 PortID exclude_slave_port_id,
381 PortID source_master_port_id,
382 const std::vector<QueuedSlavePort*>&
383 dests);
384
385 /** Function called by the port when the crossbar is recieving a Functional
386 transaction.*/
387 void recvFunctional(PacketPtr pkt, PortID slave_port_id);
388
389 /** Function called by the port when the crossbar is recieving a functional
390 snoop transaction.*/
391 void recvFunctionalSnoop(PacketPtr pkt, PortID master_port_id);
392
393 /**
394 * Forward a functional packet to our snoopers, potentially
395 * excluding one of the connected coherent masters to avoid
396 * sending a packet back to where it came from.
397 *
398 * @param pkt Packet to forward
399 * @param exclude_slave_port_id Id of slave port to exclude
400 */
401 void forwardFunctional(PacketPtr pkt, PortID exclude_slave_port_id);
402
403 /**
404 * Determine if the crossbar should sink the packet, as opposed to
405 * forwarding it, or responding.
406 */
407 bool sinkPacket(const PacketPtr pkt) const;
408
409 /**
410 * Determine if the crossbar should forward the packet, as opposed to
411 * responding to it.
412 */
413 bool forwardPacket(const PacketPtr pkt);
414
415 /**
416 * Determine if the packet's destination is the memory below
417 *
418 * The memory below is the destination for a cache mainteance
419 * operation to the Point of Coherence/Unification if this is the
420 * Point of Coherence/Unification.
421 *
422 * @param pkt The processed packet
423 *
424 * @return Whether the memory below is the destination for the packet
425 */
426 bool isDestination(const PacketPtr pkt) const
427 {
428 return (pkt->req->isToPOC() && pointOfCoherency) ||
429 (pkt->req->isToPOU() && pointOfUnification);
430 }
431
432 Stats::Scalar snoops;
433 Stats::Scalar snoopTraffic;
434 Stats::Distribution snoopFanout;
435
436 public:
437
438 virtual void init();
439
440 CoherentXBar(const CoherentXBarParams *p);
441
442 virtual ~CoherentXBar();
443
444 virtual void regStats();
445};
446
447#endif //__MEM_COHERENT_XBAR_HH__
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