2 * Copyright (c) 2006 The Regents of The University of Michigan
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
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9 * redistributions in binary form must reproduce the above copyright
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13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
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
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24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 * Definition of a bus object.
39 #include "base/misc.hh"
40 #include "base/trace.hh"
44 Bus::getPort(const std::string
&if_name
, int idx
)
46 if (if_name
== "default") {
47 if (defaultPort
== NULL
) {
48 defaultPort
= new BusPort(csprintf("%s-default",name()), this,
50 cachedBlockSizeValid
= false;
53 fatal("Default port already set\n");
56 if (if_name
== "functional") {
59 funcPort
= new BusPort(csprintf("%s-p%d-func", name(), id
), this, id
);
61 interfaces
[id
] = funcPort
;
66 // if_name ignored? forced to be empty?
68 assert(maxId
< std::numeric_limits
<typeof(maxId
)>::max());
69 BusPort
*bp
= new BusPort(csprintf("%s-p%d", name(), id
), this, id
);
71 cachedBlockSizeValid
= false;
76 Bus::deletePort(Port
*p
)
79 BusPort
*bp
= dynamic_cast<BusPort
*>(p
);
81 panic("Couldn't convert Port* to BusPort*\n");
82 // If this is our one functional port
85 interfaces
.erase(bp
->getId());
91 /** Get the ranges of anyone other buses that we are connected to. */
95 m5::hash_map
<short,BusPort
*>::iterator intIter
;
97 for (intIter
= interfaces
.begin(); intIter
!= interfaces
.end(); intIter
++)
98 intIter
->second
->sendStatusChange(Port::RangeChange
);
101 Bus::BusFreeEvent::BusFreeEvent(Bus
*_bus
) : Event(&mainEventQueue
), bus(_bus
)
104 void Bus::BusFreeEvent::process()
109 const char * Bus::BusFreeEvent::description() const
111 return "bus became available";
114 Tick
Bus::calcPacketTiming(PacketPtr pkt
)
116 // Bring tickNextIdle up to the present tick.
117 // There is some potential ambiguity where a cycle starts, which
118 // might make a difference when devices are acting right around a
119 // cycle boundary. Using a < allows things which happen exactly on
120 // a cycle boundary to take up only the following cycle. Anything
121 // that happens later will have to "wait" for the end of that
122 // cycle, and then start using the bus after that.
123 if (tickNextIdle
< curTick
) {
124 tickNextIdle
= curTick
;
125 if (tickNextIdle
% clock
!= 0)
126 tickNextIdle
= curTick
- (curTick
% clock
) + clock
;
129 Tick headerTime
= tickNextIdle
+ headerCycles
* clock
;
131 // The packet will be sent. Figure out how long it occupies the bus, and
132 // how much of that time is for the first "word", aka bus width.
134 if (pkt
->hasData()) {
135 // If a packet has data, it needs ceil(size/width) cycles to send it
136 int dataSize
= pkt
->getSize();
137 numCycles
+= dataSize
/width
;
138 if (dataSize
% width
)
142 // The first word will be delivered after the current tick, the delivery
143 // of the address if any, and one bus cycle to deliver the data
144 pkt
->firstWordTime
= headerTime
+ clock
;
146 pkt
->finishTime
= headerTime
+ numCycles
* clock
;
151 void Bus::occupyBus(Tick until
)
154 // shortcut for express snoop packets
158 tickNextIdle
= until
;
160 if (!busIdle
.scheduled()) {
161 busIdle
.schedule(tickNextIdle
);
163 busIdle
.reschedule(tickNextIdle
);
165 DPRINTF(Bus
, "The bus is now occupied from tick %d to %d\n",
166 curTick
, tickNextIdle
);
169 /** Function called by the port when the bus is receiving a Timing
172 Bus::recvTiming(PacketPtr pkt
)
174 short src
= pkt
->getSrc();
177 if (src
== defaultId
)
178 src_port
= defaultPort
;
180 src_port
= checkBusCache(src
);
181 if (src_port
== NULL
) {
182 src_port
= interfaces
[src
];
183 updateBusCache(src
, src_port
);
187 // If the bus is busy, or other devices are in line ahead of the current
188 // one, put this device on the retry list.
189 if (!pkt
->isExpressSnoop() &&
190 (tickNextIdle
> curTick
||
191 (retryList
.size() && (!inRetry
|| src_port
!= retryList
.front()))))
193 addToRetryList(src_port
);
194 DPRINTF(Bus
, "recvTiming: src %d dst %d %s 0x%x BUSY\n",
195 src
, pkt
->getDest(), pkt
->cmdString(), pkt
->getAddr());
199 DPRINTF(Bus
, "recvTiming: src %d dst %d %s 0x%x\n",
200 src
, pkt
->getDest(), pkt
->cmdString(), pkt
->getAddr());
202 Tick headerFinishTime
= pkt
->isExpressSnoop() ? 0 : calcPacketTiming(pkt
);
203 Tick packetFinishTime
= pkt
->isExpressSnoop() ? 0 : pkt
->finishTime
;
205 short dest
= pkt
->getDest();
209 if (dest
== Packet::Broadcast
) {
210 dest_port_id
= findPort(pkt
->getAddr());
211 dest_port
= (dest_port_id
== defaultId
) ?
212 defaultPort
: interfaces
[dest_port_id
];
213 SnoopIter s_end
= snoopPorts
.end();
214 for (SnoopIter s_iter
= snoopPorts
.begin(); s_iter
!= s_end
; s_iter
++) {
215 BusPort
*p
= *s_iter
;
216 if (p
!= dest_port
&& p
!= src_port
) {
217 // cache is not allowed to refuse snoop
218 bool success M5_VAR_USED
= p
->sendTiming(pkt
);
223 assert(dest
>= 0 && dest
< maxId
);
224 assert(dest
!= src
); // catch infinite loops
226 if (dest_port_id
== defaultId
)
227 dest_port
= defaultPort
;
229 dest_port
= checkBusCache(dest
);
230 if (dest_port
== NULL
) {
231 dest_port
= interfaces
[dest_port_id
];
232 // updateBusCache(dest_port_id, dest_port);
235 dest_port
= (dest_port_id
== defaultId
) ?
236 defaultPort
: interfaces
[dest_port_id
];
239 if (dest_port_id
== src
) {
240 // Must be forwarded snoop up from below...
241 assert(dest
== Packet::Broadcast
);
242 assert(src
!= defaultId
); // catch infinite loops
244 // send to actual target
245 if (!dest_port
->sendTiming(pkt
)) {
246 // Packet not successfully sent. Leave or put it on the retry list.
247 // illegal to block responses... can lead to deadlock
248 assert(!pkt
->isResponse());
249 DPRINTF(Bus
, "recvTiming: src %d dst %d %s 0x%x TGT RETRY\n",
250 src
, pkt
->getDest(), pkt
->cmdString(), pkt
->getAddr());
251 addToRetryList(src_port
);
252 occupyBus(headerFinishTime
);
255 // send OK, fall through... pkt may have been deleted by
256 // target at this point, so it should *not* be referenced
257 // again. We'll set it to NULL here just to be safe.
261 occupyBus(packetFinishTime
);
263 // Packet was successfully sent.
264 // Also take care of retries
266 DPRINTF(Bus
, "Remove retry from list %d\n", src
);
267 retryList
.front()->onRetryList(false);
268 retryList
.pop_front();
275 Bus::recvRetry(int id
)
277 // If there's anything waiting, and the bus isn't busy...
278 if (retryList
.size() && curTick
>= tickNextIdle
) {
279 //retryingPort = retryList.front();
281 DPRINTF(Bus
, "Sending a retry to %s\n", retryList
.front()->getPeer()->name());
282 retryList
.front()->sendRetry();
283 // If inRetry is still true, sendTiming wasn't called
286 retryList
.front()->onRetryList(false);
287 retryList
.pop_front();
290 //Bring tickNextIdle up to the present
291 while (tickNextIdle
< curTick
)
292 tickNextIdle
+= clock
;
294 //Burn a cycle for the missed grant.
295 tickNextIdle
+= clock
;
297 busIdle
.reschedule(tickNextIdle
, true);
300 //If we weren't able to drain before, we might be able to now.
301 if (drainEvent
&& retryList
.size() == 0 && curTick
>= tickNextIdle
) {
302 drainEvent
->process();
303 // Clear the drain event once we're done with it.
309 Bus::findPort(Addr addr
)
311 /* An interval tree would be a better way to do this. --ali. */
314 dest_id
= checkPortCache(addr
);
316 PortIter i
= portMap
.find(RangeSize(addr
,1));
317 if (i
!= portMap
.end()) {
319 updatePortCache(dest_id
, i
->first
.start
, i
->first
.end
);
323 // Check if this matches the default range
325 AddrRangeIter a_end
= defaultRange
.end();
326 for (AddrRangeIter i
= defaultRange
.begin(); i
!= a_end
; i
++) {
328 DPRINTF(Bus
, " found addr %#llx on default\n", addr
);
334 panic("Unable to find destination for addr (user set default "
335 "responder): %#llx", addr
);
337 DPRINTF(Bus
, "Unable to find destination for addr: %#llx, will use "
338 "default port", addr
);
348 /** Function called by the port when the bus is receiving a Atomic
351 Bus::recvAtomic(PacketPtr pkt
)
353 DPRINTF(Bus
, "recvAtomic: packet src %d dest %d addr 0x%x cmd %s\n",
354 pkt
->getSrc(), pkt
->getDest(), pkt
->getAddr(), pkt
->cmdString());
355 assert(pkt
->getDest() == Packet::Broadcast
);
356 assert(pkt
->isRequest());
358 // Variables for recording original command and snoop response (if
359 // any)... if a snooper respondes, we will need to restore
360 // original command so that additional snoops can take place
362 MemCmd orig_cmd
= pkt
->cmd
;
363 MemCmd snoop_response_cmd
= MemCmd::InvalidCmd
;
364 Tick snoop_response_latency
= 0;
365 int orig_src
= pkt
->getSrc();
367 int target_port_id
= findPort(pkt
->getAddr());
368 BusPort
*target_port
;
369 if (target_port_id
== defaultId
)
370 target_port
= defaultPort
;
372 target_port
= checkBusCache(target_port_id
);
373 if (target_port
== NULL
) {
374 target_port
= interfaces
[target_port_id
];
375 updateBusCache(target_port_id
, target_port
);
379 SnoopIter s_end
= snoopPorts
.end();
380 for (SnoopIter s_iter
= snoopPorts
.begin(); s_iter
!= s_end
; s_iter
++) {
381 BusPort
*p
= *s_iter
;
382 // same port should not have both target addresses and snooping
383 assert(p
!= target_port
);
384 if (p
->getId() != pkt
->getSrc()) {
385 Tick latency
= p
->sendAtomic(pkt
);
386 if (pkt
->isResponse()) {
387 // response from snoop agent
388 assert(pkt
->cmd
!= orig_cmd
);
389 assert(pkt
->memInhibitAsserted());
390 // should only happen once
391 assert(snoop_response_cmd
== MemCmd::InvalidCmd
);
392 // save response state
393 snoop_response_cmd
= pkt
->cmd
;
394 snoop_response_latency
= latency
;
395 // restore original packet state for remaining snoopers
397 pkt
->setSrc(orig_src
);
398 pkt
->setDest(Packet::Broadcast
);
403 Tick response_latency
= 0;
405 // we can get requests sent up from the memory side of the bus for
406 // snooping... don't send them back down!
407 if (target_port_id
!= pkt
->getSrc()) {
408 response_latency
= target_port
->sendAtomic(pkt
);
411 // if we got a response from a snooper, restore it here
412 if (snoop_response_cmd
!= MemCmd::InvalidCmd
) {
413 // no one else should have responded
414 assert(!pkt
->isResponse());
415 assert(pkt
->cmd
== orig_cmd
);
416 pkt
->cmd
= snoop_response_cmd
;
417 response_latency
= snoop_response_latency
;
420 // why do we have this packet field and the return value both???
421 pkt
->finishTime
= curTick
+ response_latency
;
422 return response_latency
;
425 /** Function called by the port when the bus is receiving a Functional
428 Bus::recvFunctional(PacketPtr pkt
)
430 if (!pkt
->isPrint()) {
431 // don't do DPRINTFs on PrintReq as it clutters up the output
433 "recvFunctional: packet src %d dest %d addr 0x%x cmd %s\n",
434 pkt
->getSrc(), pkt
->getDest(), pkt
->getAddr(),
437 assert(pkt
->getDest() == Packet::Broadcast
);
439 int port_id
= findPort(pkt
->getAddr());
440 Port
*port
= (port_id
== defaultId
) ? defaultPort
: interfaces
[port_id
];
441 // The packet may be changed by another bus on snoops, restore the
443 int src_id
= pkt
->getSrc();
445 assert(pkt
->isRequest()); // hasn't already been satisfied
447 SnoopIter s_end
= snoopPorts
.end();
448 for (SnoopIter s_iter
= snoopPorts
.begin(); s_iter
!= s_end
; s_iter
++) {
449 BusPort
*p
= *s_iter
;
450 if (p
!= port
&& p
->getId() != src_id
) {
451 p
->sendFunctional(pkt
);
453 if (pkt
->isResponse()) {
459 // If the snooping hasn't found what we were looking for, keep going.
460 if (!pkt
->isResponse() && port_id
!= pkt
->getSrc()) {
461 port
->sendFunctional(pkt
);
465 /** Function called by the port when the bus is receiving a status change.*/
467 Bus::recvStatusChange(Port::Status status
, int id
)
469 AddrRangeList ranges
;
473 if (inRecvStatusChange
.count(id
))
475 inRecvStatusChange
.insert(id
);
477 assert(status
== Port::RangeChange
&&
478 "The other statuses need to be implemented.");
480 DPRINTF(BusAddrRanges
, "received RangeChange from device id %d\n", id
);
483 if (id
== defaultId
) {
484 defaultRange
.clear();
485 // Only try to update these ranges if the user set a default responder.
487 defaultPort
->getPeerAddressRanges(ranges
, snoops
);
488 assert(snoops
== false);
489 for(iter
= ranges
.begin(); iter
!= ranges
.end(); iter
++) {
490 defaultRange
.push_back(*iter
);
491 DPRINTF(BusAddrRanges
, "Adding range %#llx - %#llx for default range\n",
492 iter
->start
, iter
->end
);
497 assert((id
< maxId
&& id
>= 0) || id
== defaultId
);
498 BusPort
*port
= interfaces
[id
];
500 // Clean out any previously existent ids
501 for (PortIter portIter
= portMap
.begin();
502 portIter
!= portMap
.end(); ) {
503 if (portIter
->second
== id
)
504 portMap
.erase(portIter
++);
509 for (SnoopIter s_iter
= snoopPorts
.begin();
510 s_iter
!= snoopPorts
.end(); ) {
511 if ((*s_iter
)->getId() == id
)
512 s_iter
= snoopPorts
.erase(s_iter
);
517 port
->getPeerAddressRanges(ranges
, snoops
);
520 DPRINTF(BusAddrRanges
, "Adding id %d to snoop list\n", id
);
521 snoopPorts
.push_back(port
);
524 for (iter
= ranges
.begin(); iter
!= ranges
.end(); iter
++) {
525 DPRINTF(BusAddrRanges
, "Adding range %#llx - %#llx for id %d\n",
526 iter
->start
, iter
->end
, id
);
527 if (portMap
.insert(*iter
, id
) == portMap
.end())
528 panic("Two devices with same range\n");
532 DPRINTF(MMU
, "port list has %d entries\n", portMap
.size());
534 // tell all our peers that our address range has changed.
535 // Don't tell the device that caused this change, it already knows
536 m5::hash_map
<short,BusPort
*>::iterator intIter
;
538 for (intIter
= interfaces
.begin(); intIter
!= interfaces
.end(); intIter
++)
539 if (intIter
->first
!= id
&& intIter
->first
!= funcPortId
)
540 intIter
->second
->sendStatusChange(Port::RangeChange
);
542 if (id
!= defaultId
&& defaultPort
)
543 defaultPort
->sendStatusChange(Port::RangeChange
);
544 inRecvStatusChange
.erase(id
);
548 Bus::addressRanges(AddrRangeList
&resp
, bool &snoop
, int id
)
553 DPRINTF(BusAddrRanges
, "received address range request, returning:\n");
555 for (AddrRangeIter dflt_iter
= defaultRange
.begin();
556 dflt_iter
!= defaultRange
.end(); dflt_iter
++) {
557 resp
.push_back(*dflt_iter
);
558 DPRINTF(BusAddrRanges
, " -- Dflt: %#llx : %#llx\n",dflt_iter
->start
,
561 for (PortIter portIter
= portMap
.begin();
562 portIter
!= portMap
.end(); portIter
++) {
564 for (AddrRangeIter dflt_iter
= defaultRange
.begin();
565 dflt_iter
!= defaultRange
.end(); dflt_iter
++) {
566 if ((portIter
->first
.start
< dflt_iter
->start
&&
567 portIter
->first
.end
>= dflt_iter
->start
) ||
568 (portIter
->first
.start
< dflt_iter
->end
&&
569 portIter
->first
.end
>= dflt_iter
->end
))
570 fatal("Devices can not set ranges that itersect the default set\
571 but are not a subset of the default set.\n");
572 if (portIter
->first
.start
>= dflt_iter
->start
&&
573 portIter
->first
.end
<= dflt_iter
->end
) {
575 DPRINTF(BusAddrRanges
, " -- %#llx : %#llx is a SUBSET\n",
576 portIter
->first
.start
, portIter
->first
.end
);
579 if (portIter
->second
!= id
&& !subset
) {
580 resp
.push_back(portIter
->first
);
581 DPRINTF(BusAddrRanges
, " -- %#llx : %#llx\n",
582 portIter
->first
.start
, portIter
->first
.end
);
586 for (SnoopIter s_iter
= snoopPorts
.begin(); s_iter
!= snoopPorts
.end();
588 if ((*s_iter
)->getId() != id
) {
596 Bus::findBlockSize(int id
)
598 if (cachedBlockSizeValid
)
599 return cachedBlockSize
;
603 PortIter p_end
= portMap
.end();
604 for (PortIter p_iter
= portMap
.begin(); p_iter
!= p_end
; p_iter
++) {
605 int tmp_bs
= interfaces
[p_iter
->second
]->peerBlockSize();
609 SnoopIter s_end
= snoopPorts
.end();
610 for (SnoopIter s_iter
= snoopPorts
.begin(); s_iter
!= s_end
; s_iter
++) {
611 int tmp_bs
= (*s_iter
)->peerBlockSize();
616 max_bs
= defaultBlockSize
;
619 warn_once("Blocksize found to not be 64... hmm... probably not.\n");
620 cachedBlockSize
= max_bs
;
621 cachedBlockSizeValid
= true;
627 Bus::drain(Event
* de
)
629 //We should check that we're not "doing" anything, and that noone is
630 //waiting. We might be idle but have someone waiting if the device we
631 //contacted for a retry didn't actually retry.
632 if (retryList
.size() || (curTick
< tickNextIdle
&& busIdle
.scheduled())) {
642 if (tickNextIdle
< curTick
)
643 tickNextIdle
= (curTick
/ clock
) * clock
+ clock
;
649 return new Bus(this);