1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
|
/*
* Copyright (c) 2011-2012 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Copyright (c) 2006 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Ali Saidi
* Andreas Hansson
* William Wang
*/
/**
* @file
* Definition of a bus object.
*/
#include "base/misc.hh"
#include "base/trace.hh"
#include "debug/Bus.hh"
#include "debug/BusAddrRanges.hh"
#include "mem/bus.hh"
Bus::Bus(const BusParams *p)
: MemObject(p), clock(p->clock),
headerCycles(p->header_cycles), width(p->width), tickNextIdle(0),
drainEvent(NULL), busIdleEvent(this), inRetry(false),
defaultPortID(InvalidPortID),
useDefaultRange(p->use_default_range),
defaultBlockSize(p->block_size),
cachedBlockSize(0), cachedBlockSizeValid(false)
{
//width, clock period, and header cycles must be positive
if (width <= 0)
fatal("Bus width must be positive\n");
if (clock <= 0)
fatal("Bus clock period must be positive\n");
if (headerCycles <= 0)
fatal("Number of header cycles must be positive\n");
// create the ports based on the size of the master and slave
// vector ports, and the presence of the default port, the ports
// are enumerated starting from zero
for (int i = 0; i < p->port_master_connection_count; ++i) {
std::string portName = csprintf("%s-p%d", name(), i);
MasterPort* bp = new BusMasterPort(portName, this, i);
masterPorts.push_back(bp);
}
// see if we have a default slave device connected and if so add
// our corresponding master port
if (p->port_default_connection_count) {
defaultPortID = masterPorts.size();
std::string portName = csprintf("%s-default", name());
MasterPort* bp = new BusMasterPort(portName, this, defaultPortID);
masterPorts.push_back(bp);
}
// create the slave ports, once again starting at zero
for (int i = 0; i < p->port_slave_connection_count; ++i) {
std::string portName = csprintf("%s-p%d", name(), i);
SlavePort* bp = new BusSlavePort(portName, this, i);
slavePorts.push_back(bp);
}
clearPortCache();
}
MasterPort &
Bus::getMasterPort(const std::string &if_name, int idx)
{
if (if_name == "master" && idx < masterPorts.size()) {
// the master port index translates directly to the vector position
return *masterPorts[idx];
} else if (if_name == "default") {
return *masterPorts[defaultPortID];
} else {
return MemObject::getMasterPort(if_name, idx);
}
}
SlavePort &
Bus::getSlavePort(const std::string &if_name, int idx)
{
if (if_name == "slave" && idx < slavePorts.size()) {
// the slave port index translates directly to the vector position
return *slavePorts[idx];
} else {
return MemObject::getSlavePort(if_name, idx);
}
}
void
Bus::init()
{
// iterate over our slave ports and determine which of our
// neighbouring master ports are snooping and add them as snoopers
for (SlavePortConstIter p = slavePorts.begin(); p != slavePorts.end();
++p) {
if ((*p)->getMasterPort().isSnooping()) {
DPRINTF(BusAddrRanges, "Adding snooping neighbour %s\n",
(*p)->getMasterPort().name());
snoopPorts.push_back(*p);
}
}
}
Tick
Bus::calcPacketTiming(PacketPtr pkt)
{
// determine the current time rounded to the closest following
// clock edge
Tick now = curTick();
if (now % clock != 0) {
now = ((now / clock) + 1) * clock;
}
Tick headerTime = now + headerCycles * clock;
// The packet will be sent. Figure out how long it occupies the bus, and
// how much of that time is for the first "word", aka bus width.
int numCycles = 0;
if (pkt->hasData()) {
// If a packet has data, it needs ceil(size/width) cycles to send it
int dataSize = pkt->getSize();
numCycles += dataSize/width;
if (dataSize % width)
numCycles++;
}
// The first word will be delivered after the current tick, the delivery
// of the address if any, and one bus cycle to deliver the data
pkt->firstWordTime = headerTime + clock;
pkt->finishTime = headerTime + numCycles * clock;
return headerTime;
}
void Bus::occupyBus(Tick until)
{
if (until == 0) {
// shortcut for express snoop packets
return;
}
tickNextIdle = until;
reschedule(busIdleEvent, tickNextIdle, true);
DPRINTF(Bus, "The bus is now occupied from tick %d to %d\n",
curTick(), tickNextIdle);
}
bool
Bus::isOccupied(Port* port)
{
// first we see if the next idle tick is in the future, next the
// bus is considered occupied if there are ports on the retry list
// and we are not in a retry with the current port
if (tickNextIdle > curTick() ||
(!retryList.empty() && !(inRetry && port == retryList.front()))) {
addToRetryList(port);
return true;
}
return false;
}
bool
Bus::recvTimingReq(PacketPtr pkt, PortID slave_port_id)
{
// determine the source port based on the id
SlavePort *src_port = slavePorts[slave_port_id];
// test if the bus should be considered occupied for the current
// port, and exclude express snoops from the check
if (!pkt->isExpressSnoop() && isOccupied(src_port)) {
DPRINTF(Bus, "recvTimingReq: src %s %s 0x%x BUSY\n",
src_port->name(), pkt->cmdString(), pkt->getAddr());
return false;
}
DPRINTF(Bus, "recvTimingReq: src %s %s 0x%x\n",
src_port->name(), pkt->cmdString(), pkt->getAddr());
// set the source port for routing of the response
pkt->setSrc(slave_port_id);
Tick headerFinishTime = pkt->isExpressSnoop() ? 0 : calcPacketTiming(pkt);
Tick packetFinishTime = pkt->isExpressSnoop() ? 0 : pkt->finishTime;
// uncacheable requests need never be snooped
if (!pkt->req->isUncacheable()) {
// the packet is a memory-mapped request and should be
// broadcasted to our snoopers but the source
forwardTiming(pkt, slave_port_id);
}
// remember if we add an outstanding req so we can undo it if
// necessary, if the packet needs a response, we should add it
// as outstanding and express snoops never fail so there is
// not need to worry about them
bool add_outstanding = !pkt->isExpressSnoop() && pkt->needsResponse();
// keep track that we have an outstanding request packet
// matching this request, this is used by the coherency
// mechanism in determining what to do with snoop responses
// (in recvTimingSnoop)
if (add_outstanding) {
// we should never have an exsiting request outstanding
assert(outstandingReq.find(pkt->req) == outstandingReq.end());
outstandingReq.insert(pkt->req);
}
// since it is a normal request, determine the destination
// based on the address and attempt to send the packet
bool success = masterPorts[findPort(pkt->getAddr())]->sendTimingReq(pkt);
if (!success) {
// inhibited packets should never be forced to retry
assert(!pkt->memInhibitAsserted());
// if it was added as outstanding and the send failed, then
// erase it again
if (add_outstanding)
outstandingReq.erase(pkt->req);
DPRINTF(Bus, "recvTimingReq: src %s %s 0x%x RETRY\n",
src_port->name(), pkt->cmdString(), pkt->getAddr());
addToRetryList(src_port);
occupyBus(headerFinishTime);
return false;
}
succeededTiming(packetFinishTime);
return true;
}
bool
Bus::recvTimingResp(PacketPtr pkt, PortID master_port_id)
{
// determine the source port based on the id
MasterPort *src_port = masterPorts[master_port_id];
// test if the bus should be considered occupied for the current
// port
if (isOccupied(src_port)) {
DPRINTF(Bus, "recvTimingResp: src %s %s 0x%x BUSY\n",
src_port->name(), pkt->cmdString(), pkt->getAddr());
return false;
}
DPRINTF(Bus, "recvTimingResp: src %s %s 0x%x\n",
src_port->name(), pkt->cmdString(), pkt->getAddr());
calcPacketTiming(pkt);
Tick packetFinishTime = pkt->finishTime;
// the packet is a normal response to a request that we should
// have seen passing through the bus
assert(outstandingReq.find(pkt->req) != outstandingReq.end());
// remove it as outstanding
outstandingReq.erase(pkt->req);
// send the packet to the destination through one of our slave
// ports, as determined by the destination field
bool success M5_VAR_USED = slavePorts[pkt->getDest()]->sendTimingResp(pkt);
// currently it is illegal to block responses... can lead to
// deadlock
assert(success);
succeededTiming(packetFinishTime);
return true;
}
void
Bus::recvTimingSnoopReq(PacketPtr pkt, PortID master_port_id)
{
DPRINTF(Bus, "recvTimingSnoopReq: src %s %s 0x%x\n",
masterPorts[master_port_id]->name(), pkt->cmdString(),
pkt->getAddr());
// we should only see express snoops from caches
assert(pkt->isExpressSnoop());
// set the source port for routing of the response
pkt->setSrc(master_port_id);
// forward to all snoopers
forwardTiming(pkt, InvalidPortID);
// a snoop request came from a connected slave device (one of
// our master ports), and if it is not coming from the slave
// device responsible for the address range something is
// wrong, hence there is nothing further to do as the packet
// would be going back to where it came from
assert(master_port_id == findPort(pkt->getAddr()));
// this is an express snoop and is never forced to retry
assert(!inRetry);
}
bool
Bus::recvTimingSnoopResp(PacketPtr pkt, PortID slave_port_id)
{
// determine the source port based on the id
SlavePort* src_port = slavePorts[slave_port_id];
// test if the bus should be considered occupied for the current
// port
if (isOccupied(src_port)) {
DPRINTF(Bus, "recvTimingSnoopResp: src %s %s 0x%x BUSY\n",
src_port->name(), pkt->cmdString(), pkt->getAddr());
return false;
}
DPRINTF(Bus, "recvTimingSnoop: src %s %s 0x%x\n",
src_port->name(), pkt->cmdString(), pkt->getAddr());
// get the destination from the packet
PortID dest = pkt->getDest();
// responses are never express snoops
assert(!pkt->isExpressSnoop());
calcPacketTiming(pkt);
Tick packetFinishTime = pkt->finishTime;
// determine if the response is from a snoop request we
// created as the result of a normal request (in which case it
// should be in the outstandingReq), or if we merely forwarded
// someone else's snoop request
if (outstandingReq.find(pkt->req) == outstandingReq.end()) {
// this is a snoop response to a snoop request we
// forwarded, e.g. coming from the L1 and going to the L2
// this should be forwarded as a snoop response
bool success M5_VAR_USED = masterPorts[dest]->sendTimingSnoopResp(pkt);
assert(success);
} else {
// we got a snoop response on one of our slave ports,
// i.e. from a coherent master connected to the bus, and
// since we created the snoop request as part of
// recvTiming, this should now be a normal response again
outstandingReq.erase(pkt->req);
// this is a snoop response from a coherent master, with a
// destination field set on its way through the bus as
// request, hence it should never go back to where the
// snoop response came from, but instead to where the
// original request came from
assert(slave_port_id != dest);
// as a normal response, it should go back to a master
// through one of our slave ports
bool success M5_VAR_USED = slavePorts[dest]->sendTimingResp(pkt);
// currently it is illegal to block responses... can lead
// to deadlock
assert(success);
}
succeededTiming(packetFinishTime);
return true;
}
void
Bus::succeededTiming(Tick busy_time)
{
// occupy the bus accordingly
occupyBus(busy_time);
// if a retrying port succeeded, also take it off the retry list
if (inRetry) {
DPRINTF(Bus, "Remove retry from list %s\n",
retryList.front()->name());
retryList.pop_front();
inRetry = false;
}
}
void
Bus::forwardTiming(PacketPtr pkt, PortID exclude_slave_port_id)
{
for (SlavePortIter s = snoopPorts.begin(); s != snoopPorts.end(); ++s) {
SlavePort *p = *s;
// we could have gotten this request from a snooping master
// (corresponding to our own slave port that is also in
// snoopPorts) and should not send it back to where it came
// from
if (exclude_slave_port_id == InvalidPortID ||
p->getId() != exclude_slave_port_id) {
// cache is not allowed to refuse snoop
p->sendTimingSnoopReq(pkt);
}
}
}
void
Bus::releaseBus()
{
// releasing the bus means we should now be idle
assert(curTick() >= tickNextIdle);
// bus is now idle, so if someone is waiting we can retry
if (!retryList.empty()) {
// note that we block (return false on recvTiming) both
// because the bus is busy and because the destination is
// busy, and in the latter case the bus may be released before
// we see a retry from the destination
retryWaiting();
}
//If we weren't able to drain before, we might be able to now.
if (drainEvent && retryList.empty() && curTick() >= tickNextIdle) {
drainEvent->process();
// Clear the drain event once we're done with it.
drainEvent = NULL;
}
}
void
Bus::retryWaiting()
{
// this should never be called with an empty retry list
assert(!retryList.empty());
// send a retry to the port at the head of the retry list
inRetry = true;
// note that we might have blocked on the receiving port being
// busy (rather than the bus itself) and now call retry before the
// destination called retry on the bus
retryList.front()->sendRetry();
// If inRetry is still true, sendTiming wasn't called in zero time
// (e.g. the cache does this)
if (inRetry) {
retryList.pop_front();
inRetry = false;
//Bring tickNextIdle up to the present
while (tickNextIdle < curTick())
tickNextIdle += clock;
//Burn a cycle for the missed grant.
tickNextIdle += clock;
reschedule(busIdleEvent, tickNextIdle, true);
}
}
void
Bus::recvRetry()
{
// we got a retry from a peer that we tried to send something to
// and failed, but we sent it on the account of someone else, and
// that source port should be on our retry list, however if the
// bus is released before this happens and the retry (from the bus
// point of view) is successful then this no longer holds and we
// could in fact have an empty retry list
if (retryList.empty())
return;
// if the bus isn't busy
if (curTick() >= tickNextIdle) {
// note that we do not care who told us to retry at the moment, we
// merely let the first one on the retry list go
retryWaiting();
}
}
PortID
Bus::findPort(Addr addr)
{
/* An interval tree would be a better way to do this. --ali. */
PortID dest_id = checkPortCache(addr);
if (dest_id != InvalidPortID)
return dest_id;
// Check normal port ranges
PortIter i = portMap.find(RangeSize(addr,1));
if (i != portMap.end()) {
dest_id = i->second;
updatePortCache(dest_id, i->first.start, i->first.end);
return dest_id;
}
// Check if this matches the default range
if (useDefaultRange) {
AddrRangeIter a_end = defaultRange.end();
for (AddrRangeIter i = defaultRange.begin(); i != a_end; i++) {
if (*i == addr) {
DPRINTF(Bus, " found addr %#llx on default\n", addr);
return defaultPortID;
}
}
} else if (defaultPortID != InvalidPortID) {
DPRINTF(Bus, "Unable to find destination for addr %#llx, "
"will use default port\n", addr);
return defaultPortID;
}
// we should use the range for the default port and it did not
// match, or the default port is not set
fatal("Unable to find destination for addr %#llx on bus %s\n", addr,
name());
}
Tick
Bus::recvAtomic(PacketPtr pkt, PortID slave_port_id)
{
DPRINTF(Bus, "recvAtomic: packet src %s addr 0x%x cmd %s\n",
slavePorts[slave_port_id]->name(), pkt->getAddr(),
pkt->cmdString());
MemCmd snoop_response_cmd = MemCmd::InvalidCmd;
Tick snoop_response_latency = 0;
// uncacheable requests need never be snooped
if (!pkt->req->isUncacheable()) {
// forward to all snoopers but the source
std::pair<MemCmd, Tick> snoop_result =
forwardAtomic(pkt, slave_port_id);
snoop_response_cmd = snoop_result.first;
snoop_response_latency = snoop_result.second;
}
// even if we had a snoop response, we must continue and also
// perform the actual request at the destination
PortID dest_id = findPort(pkt->getAddr());
// forward the request to the appropriate destination
Tick response_latency = masterPorts[dest_id]->sendAtomic(pkt);
// if we got a response from a snooper, restore it here
if (snoop_response_cmd != MemCmd::InvalidCmd) {
// no one else should have responded
assert(!pkt->isResponse());
pkt->cmd = snoop_response_cmd;
response_latency = snoop_response_latency;
}
pkt->finishTime = curTick() + response_latency;
return response_latency;
}
Tick
Bus::recvAtomicSnoop(PacketPtr pkt, PortID master_port_id)
{
DPRINTF(Bus, "recvAtomicSnoop: packet src %s addr 0x%x cmd %s\n",
masterPorts[master_port_id]->name(), pkt->getAddr(),
pkt->cmdString());
// forward to all snoopers
std::pair<MemCmd, Tick> snoop_result =
forwardAtomic(pkt, InvalidPortID);
MemCmd snoop_response_cmd = snoop_result.first;
Tick snoop_response_latency = snoop_result.second;
if (snoop_response_cmd != MemCmd::InvalidCmd)
pkt->cmd = snoop_response_cmd;
pkt->finishTime = curTick() + snoop_response_latency;
return snoop_response_latency;
}
std::pair<MemCmd, Tick>
Bus::forwardAtomic(PacketPtr pkt, PortID exclude_slave_port_id)
{
// the packet may be changed on snoops, record the original
// command to enable us to restore it between snoops so that
// additional snoops can take place properly
MemCmd orig_cmd = pkt->cmd;
MemCmd snoop_response_cmd = MemCmd::InvalidCmd;
Tick snoop_response_latency = 0;
for (SlavePortIter s = snoopPorts.begin(); s != snoopPorts.end(); ++s) {
SlavePort *p = *s;
// we could have gotten this request from a snooping master
// (corresponding to our own slave port that is also in
// snoopPorts) and should not send it back to where it came
// from
if (exclude_slave_port_id == InvalidPortID ||
p->getId() != exclude_slave_port_id) {
Tick latency = p->sendAtomicSnoop(pkt);
// in contrast to a functional access, we have to keep on
// going as all snoopers must be updated even if we get a
// response
if (pkt->isResponse()) {
// response from snoop agent
assert(pkt->cmd != orig_cmd);
assert(pkt->memInhibitAsserted());
// should only happen once
assert(snoop_response_cmd == MemCmd::InvalidCmd);
// save response state
snoop_response_cmd = pkt->cmd;
snoop_response_latency = latency;
// restore original packet state for remaining snoopers
pkt->cmd = orig_cmd;
}
}
}
// the packet is restored as part of the loop and any potential
// snoop response is part of the returned pair
return std::make_pair(snoop_response_cmd, snoop_response_latency);
}
void
Bus::recvFunctional(PacketPtr pkt, PortID slave_port_id)
{
if (!pkt->isPrint()) {
// don't do DPRINTFs on PrintReq as it clutters up the output
DPRINTF(Bus,
"recvFunctional: packet src %s addr 0x%x cmd %s\n",
slavePorts[slave_port_id]->name(), pkt->getAddr(),
pkt->cmdString());
}
// uncacheable requests need never be snooped
if (!pkt->req->isUncacheable()) {
// forward to all snoopers but the source
forwardFunctional(pkt, slave_port_id);
}
// there is no need to continue if the snooping has found what we
// were looking for and the packet is already a response
if (!pkt->isResponse()) {
PortID dest_id = findPort(pkt->getAddr());
masterPorts[dest_id]->sendFunctional(pkt);
}
}
void
Bus::recvFunctionalSnoop(PacketPtr pkt, PortID master_port_id)
{
if (!pkt->isPrint()) {
// don't do DPRINTFs on PrintReq as it clutters up the output
DPRINTF(Bus,
"recvFunctionalSnoop: packet src %s addr 0x%x cmd %s\n",
masterPorts[master_port_id]->name(), pkt->getAddr(),
pkt->cmdString());
}
// forward to all snoopers
forwardFunctional(pkt, InvalidPortID);
}
void
Bus::forwardFunctional(PacketPtr pkt, PortID exclude_slave_port_id)
{
for (SlavePortIter s = snoopPorts.begin(); s != snoopPorts.end(); ++s) {
SlavePort *p = *s;
// we could have gotten this request from a snooping master
// (corresponding to our own slave port that is also in
// snoopPorts) and should not send it back to where it came
// from
if (exclude_slave_port_id == InvalidPortID ||
p->getId() != exclude_slave_port_id)
p->sendFunctionalSnoop(pkt);
// if we get a response we are done
if (pkt->isResponse()) {
break;
}
}
}
/** Function called by the port when the bus is receiving a range change.*/
void
Bus::recvRangeChange(PortID master_port_id)
{
AddrRangeList ranges;
AddrRangeIter iter;
if (inRecvRangeChange.count(master_port_id))
return;
inRecvRangeChange.insert(master_port_id);
DPRINTF(BusAddrRanges, "received RangeChange from device id %d\n",
master_port_id);
clearPortCache();
if (master_port_id == defaultPortID) {
defaultRange.clear();
// Only try to update these ranges if the user set a default responder.
if (useDefaultRange) {
AddrRangeList ranges =
masterPorts[master_port_id]->getSlavePort().getAddrRanges();
for(iter = ranges.begin(); iter != ranges.end(); iter++) {
defaultRange.push_back(*iter);
DPRINTF(BusAddrRanges, "Adding range %#llx - %#llx for default range\n",
iter->start, iter->end);
}
}
} else {
assert(master_port_id < masterPorts.size() && master_port_id >= 0);
MasterPort *port = masterPorts[master_port_id];
// Clean out any previously existent ids
for (PortIter portIter = portMap.begin();
portIter != portMap.end(); ) {
if (portIter->second == master_port_id)
portMap.erase(portIter++);
else
portIter++;
}
ranges = port->getSlavePort().getAddrRanges();
for (iter = ranges.begin(); iter != ranges.end(); iter++) {
DPRINTF(BusAddrRanges, "Adding range %#llx - %#llx for id %d\n",
iter->start, iter->end, master_port_id);
if (portMap.insert(*iter, master_port_id) == portMap.end()) {
PortID conflict_id = portMap.find(*iter)->second;
fatal("%s has two ports with same range:\n\t%s\n\t%s\n",
name(),
masterPorts[master_port_id]->getSlavePort().name(),
masterPorts[conflict_id]->getSlavePort().name());
}
}
}
DPRINTF(BusAddrRanges, "port list has %d entries\n", portMap.size());
// tell all our neighbouring master ports that our address range
// has changed
for (SlavePortConstIter p = slavePorts.begin(); p != slavePorts.end();
++p)
(*p)->sendRangeChange();
inRecvRangeChange.erase(master_port_id);
}
AddrRangeList
Bus::getAddrRanges()
{
AddrRangeList ranges;
DPRINTF(BusAddrRanges, "received address range request, returning:\n");
for (AddrRangeIter dflt_iter = defaultRange.begin();
dflt_iter != defaultRange.end(); dflt_iter++) {
ranges.push_back(*dflt_iter);
DPRINTF(BusAddrRanges, " -- Dflt: %#llx : %#llx\n",dflt_iter->start,
dflt_iter->end);
}
for (PortIter portIter = portMap.begin();
portIter != portMap.end(); portIter++) {
bool subset = false;
for (AddrRangeIter dflt_iter = defaultRange.begin();
dflt_iter != defaultRange.end(); dflt_iter++) {
if ((portIter->first.start < dflt_iter->start &&
portIter->first.end >= dflt_iter->start) ||
(portIter->first.start < dflt_iter->end &&
portIter->first.end >= dflt_iter->end))
fatal("Devices can not set ranges that itersect the default set\
but are not a subset of the default set.\n");
if (portIter->first.start >= dflt_iter->start &&
portIter->first.end <= dflt_iter->end) {
subset = true;
DPRINTF(BusAddrRanges, " -- %#llx : %#llx is a SUBSET\n",
portIter->first.start, portIter->first.end);
}
}
if (!subset) {
ranges.push_back(portIter->first);
DPRINTF(BusAddrRanges, " -- %#llx : %#llx\n",
portIter->first.start, portIter->first.end);
}
}
return ranges;
}
bool
Bus::isSnooping() const
{
// in essence, answer the question if there are snooping ports
return !snoopPorts.empty();
}
unsigned
Bus::findBlockSize()
{
if (cachedBlockSizeValid)
return cachedBlockSize;
unsigned max_bs = 0;
PortIter p_end = portMap.end();
for (PortIter p_iter = portMap.begin(); p_iter != p_end; p_iter++) {
unsigned tmp_bs = masterPorts[p_iter->second]->peerBlockSize();
if (tmp_bs > max_bs)
max_bs = tmp_bs;
}
for (SlavePortConstIter s = snoopPorts.begin(); s != snoopPorts.end();
++s) {
unsigned tmp_bs = (*s)->peerBlockSize();
if (tmp_bs > max_bs)
max_bs = tmp_bs;
}
if (max_bs == 0)
max_bs = defaultBlockSize;
if (max_bs != 64)
warn_once("Blocksize found to not be 64... hmm... probably not.\n");
cachedBlockSize = max_bs;
cachedBlockSizeValid = true;
return max_bs;
}
unsigned int
Bus::drain(Event * de)
{
//We should check that we're not "doing" anything, and that noone is
//waiting. We might be idle but have someone waiting if the device we
//contacted for a retry didn't actually retry.
if (!retryList.empty() || (curTick() < tickNextIdle &&
busIdleEvent.scheduled())) {
drainEvent = de;
return 1;
}
return 0;
}
void
Bus::startup()
{
if (tickNextIdle < curTick())
tickNextIdle = (curTick() / clock) * clock + clock;
}
Bus *
BusParams::create()
{
return new Bus(this);
}
|