2 * Copyright (c) 2006 The Regents of The University of Michigan
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33 * Definition of a bus object.
37 #include "base/misc.hh"
38 #include "base/trace.hh"
40 #include "sim/builder.hh"
43 Bus::getPort(const std::string
&if_name
, int idx
)
45 if (if_name
== "default") {
46 if (defaultPort
== NULL
) {
47 defaultPort
= new BusPort(csprintf("%s-default",name()), this,
51 fatal("Default port already set\n");
54 // if_name ignored? forced to be empty?
55 int id
= interfaces
.size();
56 BusPort
*bp
= new BusPort(csprintf("%s-p%d", name(), id
), this, id
);
57 interfaces
.push_back(bp
);
61 /** Get the ranges of anyone other buses that we are connected to. */
65 std::vector
<BusPort
*>::iterator intIter
;
67 for (intIter
= interfaces
.begin(); intIter
!= interfaces
.end(); intIter
++)
68 (*intIter
)->sendStatusChange(Port::RangeChange
);
71 Bus::BusFreeEvent::BusFreeEvent(Bus
*_bus
) : Event(&mainEventQueue
), bus(_bus
)
74 void Bus::BusFreeEvent::process()
79 const char * Bus::BusFreeEvent::description()
81 return "bus became available";
84 void Bus::occupyBus(PacketPtr pkt
)
86 //Bring tickNextIdle up to the present tick
87 //There is some potential ambiguity where a cycle starts, which might make
88 //a difference when devices are acting right around a cycle boundary. Using
89 //a < allows things which happen exactly on a cycle boundary to take up only
90 //the following cycle. Anthing that happens later will have to "wait" for
91 //the end of that cycle, and then start using the bus after that.
92 while (tickNextIdle
< curTick
)
93 tickNextIdle
+= clock
;
95 // The packet will be sent. Figure out how long it occupies the bus, and
96 // how much of that time is for the first "word", aka bus width.
98 // Requests need one cycle to send an address
101 else if (pkt
->isResponse() || pkt
->hasData()) {
102 // If a packet has data, it needs ceil(size/width) cycles to send it
103 // We're using the "adding instead of dividing" trick again here
104 if (pkt
->hasData()) {
105 int dataSize
= pkt
->getSize();
106 for (int transmitted
= 0; transmitted
< dataSize
;
107 transmitted
+= width
) {
111 // If the packet didn't have data, it must have been a response.
112 // Those use the bus for one cycle to send their data.
117 // The first word will be delivered after the current tick, the delivery
118 // of the address if any, and one bus cycle to deliver the data
121 pkt
->isRequest() ? clock
: 0 +
124 //Advance it numCycles bus cycles.
125 //XXX Should this use the repeated addition trick as well?
126 tickNextIdle
+= (numCycles
* clock
);
127 if (!busIdle
.scheduled()) {
128 busIdle
.schedule(tickNextIdle
);
130 busIdle
.reschedule(tickNextIdle
);
132 DPRINTF(Bus
, "The bus is now occupied from tick %d to %d\n",
133 curTick
, tickNextIdle
);
135 // The bus will become idle once the current packet is delivered.
136 pkt
->finishTime
= tickNextIdle
;
139 /** Function called by the port when the bus is receiving a Timing
142 Bus::recvTiming(PacketPtr pkt
)
145 DPRINTF(Bus
, "recvTiming: packet src %d dest %d addr 0x%x cmd %s\n",
146 pkt
->getSrc(), pkt
->getDest(), pkt
->getAddr(), pkt
->cmdString());
149 if (pkt
->getSrc() == defaultId
)
150 pktPort
= defaultPort
;
151 else pktPort
= interfaces
[pkt
->getSrc()];
153 // If the bus is busy, or other devices are in line ahead of the current
154 // one, put this device on the retry list.
155 if (tickNextIdle
> curTick
||
156 (retryList
.size() && (!inRetry
|| pktPort
!= retryList
.front()))) {
157 addToRetryList(pktPort
);
161 short dest
= pkt
->getDest();
163 // Make sure to clear the snoop commit flag so it doesn't think an
164 // access has been handled twice.
165 if (dest
== Packet::Broadcast
) {
166 port
= findPort(pkt
->getAddr(), pkt
->getSrc());
167 pkt
->flags
&= ~SNOOP_COMMIT
;
168 if (timingSnoop(pkt
, port
? port
: interfaces
[pkt
->getSrc()])) {
171 pkt
->flags
|= SNOOP_COMMIT
;
172 success
= timingSnoop(pkt
, port
? port
: interfaces
[pkt
->getSrc()]);
175 if (pkt
->flags
& SATISFIED
) {
176 //Cache-Cache transfer occuring
178 retryList
.front()->onRetryList(false);
179 retryList
.pop_front();
186 //Snoop didn't succeed
187 DPRINTF(Bus
, "Adding a retry to RETRY list %i\n", pktPort
);
188 addToRetryList(pktPort
);
192 assert(dest
>= 0 && dest
< interfaces
.size());
193 assert(dest
!= pkt
->getSrc()); // catch infinite loops
194 port
= interfaces
[dest
];
200 if (port
->sendTiming(pkt
)) {
201 // Packet was successfully sent. Return true.
202 // Also take care of retries
204 DPRINTF(Bus
, "Remove retry from list %i\n", retryList
.front());
205 retryList
.front()->onRetryList(false);
206 retryList
.pop_front();
212 // Packet not successfully sent. Leave or put it on the retry list.
213 DPRINTF(Bus
, "Adding a retry to RETRY list %i\n", pktPort
);
214 addToRetryList(pktPort
);
218 //Forwarding up from responder, just return true;
224 Bus::recvRetry(int id
)
226 DPRINTF(Bus
, "Received a retry\n");
227 // If there's anything waiting, and the bus isn't busy...
228 if (retryList
.size() && curTick
>= tickNextIdle
) {
229 //retryingPort = retryList.front();
231 DPRINTF(Bus
, "Sending a retry\n");
232 retryList
.front()->sendRetry();
233 // If inRetry is still true, sendTiming wasn't called
236 retryList
.front()->onRetryList(false);
237 retryList
.pop_front();
240 //Bring tickNextIdle up to the present
241 while (tickNextIdle
< curTick
)
242 tickNextIdle
+= clock
;
244 //Burn a cycle for the missed grant.
245 tickNextIdle
+= clock
;
247 if (!busIdle
.scheduled()) {
248 busIdle
.schedule(tickNextIdle
);
250 busIdle
.reschedule(tickNextIdle
);
254 //If we weren't able to drain before, we might be able to now.
255 if (drainEvent
&& retryList
.size() == 0 && curTick
>= tickNextIdle
) {
256 drainEvent
->process();
257 // Clear the drain event once we're done with it.
263 Bus::findPort(Addr addr
, int id
)
265 /* An interval tree would be a better way to do this. --ali. */
268 range_map
<Addr
,int>::iterator i
;
270 i
= portMap
.find(RangeSize(addr
,1));
271 if (i
!= portMap
.end())
274 // Check if this matches the default range
276 for (iter
= defaultRange
.begin(); iter
!= defaultRange
.end(); iter
++) {
278 DPRINTF(Bus
, " found addr %#llx on default\n", addr
);
284 panic("Unable to find destination for addr (user set default "
285 "responder): %#llx", addr
);
287 DPRINTF(Bus
, "Unable to find destination for addr: %#llx, will use "
288 "default port", addr
);
295 // we shouldn't be sending this back to where it came from
296 // do the snoop access and then we should terminate
297 // the cyclical call.
301 return interfaces
[dest_id
];
305 Bus::findSnoopPorts(Addr addr
, int id
)
309 std::vector
<int> ports
;
311 while (i
< portSnoopList
.size())
313 if (portSnoopList
[i
].range
== addr
&& portSnoopList
[i
].portId
!= id
) {
314 //Careful to not overlap ranges
315 //or snoop will be called more than once on the port
317 //@todo Fix this hack because ranges are overlapping
318 //need to make sure we dont't create overlapping ranges
319 bool hack_overlap
= false;
320 int size
= ports
.size();
321 for (int j
=0; j
< size
; j
++) {
322 if (ports
[j
] == portSnoopList
[i
].portId
)
327 ports
.push_back(portSnoopList
[i
].portId
);
328 // DPRINTF(Bus, " found snoop addr %#llx on device%d\n", addr,
329 // portSnoopList[i].portId);
337 Bus::atomicSnoop(PacketPtr pkt
, Port
*responder
)
339 std::vector
<int> ports
= findSnoopPorts(pkt
->getAddr(), pkt
->getSrc());
340 Tick response_time
= 0;
342 while (!ports
.empty())
344 if (interfaces
[ports
.back()] != responder
) {
345 Tick response
= interfaces
[ports
.back()]->sendAtomic(pkt
);
347 assert(!response_time
); //Multiple responders
348 response_time
= response
;
353 return response_time
;
357 Bus::functionalSnoop(PacketPtr pkt
, Port
*responder
)
359 std::vector
<int> ports
= findSnoopPorts(pkt
->getAddr(), pkt
->getSrc());
361 //The packet may be changed by another bus on snoops, restore the id after each
362 int id
= pkt
->getSrc();
363 while (!ports
.empty() && pkt
->result
!= Packet::Success
)
365 if (interfaces
[ports
.back()] != responder
)
366 interfaces
[ports
.back()]->sendFunctional(pkt
);
373 Bus::timingSnoop(PacketPtr pkt
, Port
* responder
)
375 std::vector
<int> ports
= findSnoopPorts(pkt
->getAddr(), pkt
->getSrc());
378 while (!ports
.empty() && success
)
380 if (interfaces
[ports
.back()] != responder
) //Don't call if responder also, once will do
381 success
= interfaces
[ports
.back()]->sendTiming(pkt
);
389 /** Function called by the port when the bus is receiving a Atomic
392 Bus::recvAtomic(PacketPtr pkt
)
394 DPRINTF(Bus
, "recvAtomic: packet src %d dest %d addr 0x%x cmd %s\n",
395 pkt
->getSrc(), pkt
->getDest(), pkt
->getAddr(), pkt
->cmdString());
396 assert(pkt
->getDest() == Packet::Broadcast
);
397 pkt
->flags
|= SNOOP_COMMIT
;
399 // Assume one bus cycle in order to get through. This may have
400 // some clock skew issues yet again...
401 pkt
->finishTime
= curTick
+ clock
;
403 Port
*port
= findPort(pkt
->getAddr(), pkt
->getSrc());
404 Tick snoopTime
= atomicSnoop(pkt
, port
? port
: interfaces
[pkt
->getSrc()]);
407 return snoopTime
; //Snoop satisfies it
409 return port
->sendAtomic(pkt
);
414 /** Function called by the port when the bus is receiving a Functional
417 Bus::recvFunctional(PacketPtr pkt
)
419 DPRINTF(Bus
, "recvFunctional: packet src %d dest %d addr 0x%x cmd %s\n",
420 pkt
->getSrc(), pkt
->getDest(), pkt
->getAddr(), pkt
->cmdString());
421 assert(pkt
->getDest() == Packet::Broadcast
);
422 pkt
->flags
|= SNOOP_COMMIT
;
424 Port
* port
= findPort(pkt
->getAddr(), pkt
->getSrc());
425 functionalSnoop(pkt
, port
? port
: interfaces
[pkt
->getSrc()]);
427 // If the snooping found what we were looking for, we're done.
428 if (pkt
->result
!= Packet::Success
&& port
) {
429 port
->sendFunctional(pkt
);
433 /** Function called by the port when the bus is receiving a status change.*/
435 Bus::recvStatusChange(Port::Status status
, int id
)
437 AddrRangeList ranges
;
438 AddrRangeList snoops
;
442 assert(status
== Port::RangeChange
&&
443 "The other statuses need to be implemented.");
445 DPRINTF(BusAddrRanges
, "received RangeChange from device id %d\n", id
);
447 if (id
== defaultId
) {
448 defaultRange
.clear();
449 // Only try to update these ranges if the user set a default responder.
451 defaultPort
->getPeerAddressRanges(ranges
, snoops
);
452 assert(snoops
.size() == 0);
453 for(iter
= ranges
.begin(); iter
!= ranges
.end(); iter
++) {
454 defaultRange
.push_back(*iter
);
455 DPRINTF(BusAddrRanges
, "Adding range %#llx - %#llx for default range\n",
456 iter
->start
, iter
->end
);
461 assert((id
< interfaces
.size() && id
>= 0) || id
== defaultId
);
462 Port
*port
= interfaces
[id
];
463 range_map
<Addr
,int>::iterator portIter
;
464 std::vector
<DevMap
>::iterator snoopIter
;
466 // Clean out any previously existent ids
467 for (portIter
= portMap
.begin(); portIter
!= portMap
.end(); ) {
468 if (portIter
->second
== id
)
469 portMap
.erase(portIter
++);
474 for (snoopIter
= portSnoopList
.begin(); snoopIter
!= portSnoopList
.end(); ) {
475 if (snoopIter
->portId
== id
)
476 snoopIter
= portSnoopList
.erase(snoopIter
);
481 port
->getPeerAddressRanges(ranges
, snoops
);
483 for(iter
= snoops
.begin(); iter
!= snoops
.end(); iter
++) {
488 //@todo, make sure we don't overlap ranges
489 DPRINTF(BusAddrRanges
, "Adding snoop range %#llx - %#llx for id %d\n",
490 dm
.range
.start
, dm
.range
.end
, id
);
491 portSnoopList
.push_back(dm
);
494 for(iter
= ranges
.begin(); iter
!= ranges
.end(); iter
++) {
495 DPRINTF(BusAddrRanges
, "Adding range %#llx - %#llx for id %d\n",
496 iter
->start
, iter
->end
, id
);
497 if (portMap
.insert(*iter
, id
) == portMap
.end())
498 panic("Two devices with same range\n");
502 DPRINTF(MMU
, "port list has %d entries\n", portMap
.size());
504 // tell all our peers that our address range has changed.
505 // Don't tell the device that caused this change, it already knows
506 for (x
= 0; x
< interfaces
.size(); x
++)
508 interfaces
[x
]->sendStatusChange(Port::RangeChange
);
510 if (id
!= defaultId
&& defaultPort
)
511 defaultPort
->sendStatusChange(Port::RangeChange
);
515 Bus::addressRanges(AddrRangeList
&resp
, AddrRangeList
&snoop
, int id
)
517 std::vector
<DevMap
>::iterator snoopIter
;
518 range_map
<Addr
,int>::iterator portIter
;
519 AddrRangeIter dflt_iter
;
525 DPRINTF(BusAddrRanges
, "received address range request, returning:\n");
527 for (dflt_iter
= defaultRange
.begin(); dflt_iter
!= defaultRange
.end();
529 resp
.push_back(*dflt_iter
);
530 DPRINTF(BusAddrRanges
, " -- Dflt: %#llx : %#llx\n",dflt_iter
->start
,
533 for (portIter
= portMap
.begin(); portIter
!= portMap
.end(); portIter
++) {
535 for (dflt_iter
= defaultRange
.begin(); dflt_iter
!= defaultRange
.end();
537 if ((portIter
->first
.start
< dflt_iter
->start
&&
538 portIter
->first
.end
>= dflt_iter
->start
) ||
539 (portIter
->first
.start
< dflt_iter
->end
&&
540 portIter
->first
.end
>= dflt_iter
->end
))
541 fatal("Devices can not set ranges that itersect the default set\
542 but are not a subset of the default set.\n");
543 if (portIter
->first
.start
>= dflt_iter
->start
&&
544 portIter
->first
.end
<= dflt_iter
->end
) {
546 DPRINTF(BusAddrRanges
, " -- %#llx : %#llx is a SUBSET\n",
547 portIter
->first
.start
, portIter
->first
.end
);
550 if (portIter
->second
!= id
&& !subset
) {
551 resp
.push_back(portIter
->first
);
552 DPRINTF(BusAddrRanges
, " -- %#llx : %#llx\n",
553 portIter
->first
.start
, portIter
->first
.end
);
557 for (snoopIter
= portSnoopList
.begin();
558 snoopIter
!= portSnoopList
.end(); snoopIter
++)
560 if (snoopIter
->portId
!= id
) {
561 snoop
.push_back(snoopIter
->range
);
562 DPRINTF(BusAddrRanges
, " -- Snoop: %#llx : %#llx\n",
563 snoopIter
->range
.start
, snoopIter
->range
.end
);
564 //@todo We need to properly insert snoop ranges
565 //not overlapping the ranges (multiple)
571 Bus::drain(Event
* de
)
573 //We should check that we're not "doing" anything, and that noone is
574 //waiting. We might be idle but have someone waiting if the device we
575 //contacted for a retry didn't actually retry.
576 if (curTick
>= tickNextIdle
&& retryList
.size() == 0) {
584 BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bus
)
589 Param
<bool> responder_set
;
591 END_DECLARE_SIM_OBJECT_PARAMS(Bus
)
593 BEGIN_INIT_SIM_OBJECT_PARAMS(Bus
)
594 INIT_PARAM(bus_id
, "a globally unique bus id"),
595 INIT_PARAM(clock
, "bus clock speed"),
596 INIT_PARAM(width
, "width of the bus (bits)"),
597 INIT_PARAM(responder_set
, "Is a default responder set by the user")
598 END_INIT_SIM_OBJECT_PARAMS(Bus
)
600 CREATE_SIM_OBJECT(Bus
)
602 return new Bus(getInstanceName(), bus_id
, clock
, width
, responder_set
);
605 REGISTER_SIM_OBJECT("Bus", Bus
)