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");
53 // if_name ignored? forced to be empty?
54 int id
= interfaces
.size();
55 BusPort
*bp
= new BusPort(csprintf("%s-p%d", name(), id
), this, id
);
56 interfaces
.push_back(bp
);
60 /** Get the ranges of anyone other buses that we are connected to. */
64 std::vector
<BusPort
*>::iterator intIter
;
66 for (intIter
= interfaces
.begin(); intIter
!= interfaces
.end(); intIter
++)
67 (*intIter
)->sendStatusChange(Port::RangeChange
);
70 Bus::BusFreeEvent::BusFreeEvent(Bus
*_bus
) : Event(&mainEventQueue
), bus(_bus
)
73 void Bus::BusFreeEvent::process()
78 const char * Bus::BusFreeEvent::description()
80 return "bus became available";
83 void Bus::occupyBus(PacketPtr pkt
)
85 //Bring tickNextIdle up to the present tick
86 //There is some potential ambiguity where a cycle starts, which might make
87 //a difference when devices are acting right around a cycle boundary. Using
88 //a < allows things which happen exactly on a cycle boundary to take up only
89 //the following cycle. Anthing that happens later will have to "wait" for
90 //the end of that cycle, and then start using the bus after that.
91 while (tickNextIdle
< curTick
)
92 tickNextIdle
+= clock
;
94 // The packet will be sent. Figure out how long it occupies the bus, and
95 // how much of that time is for the first "word", aka bus width.
97 // Requests need one cycle to send an address
100 else if (pkt
->isResponse() || pkt
->hasData()) {
101 // If a packet has data, it needs ceil(size/width) cycles to send it
102 // We're using the "adding instead of dividing" trick again here
103 if (pkt
->hasData()) {
104 int dataSize
= pkt
->getSize();
105 for (int transmitted
= 0; transmitted
< dataSize
;
106 transmitted
+= width
) {
110 // If the packet didn't have data, it must have been a response.
111 // Those use the bus for one cycle to send their data.
116 // The first word will be delivered after the current tick, the delivery
117 // of the address if any, and one bus cycle to deliver the data
120 pkt
->isRequest() ? clock
: 0 +
123 //Advance it numCycles bus cycles.
124 //XXX Should this use the repeated addition trick as well?
125 tickNextIdle
+= (numCycles
* clock
);
126 if (!busIdle
.scheduled()) {
127 busIdle
.schedule(tickNextIdle
);
129 busIdle
.reschedule(tickNextIdle
);
131 DPRINTF(Bus
, "The bus is now occupied from tick %d to %d\n",
132 curTick
, tickNextIdle
);
134 // The bus will become idle once the current packet is delivered.
135 pkt
->finishTime
= tickNextIdle
;
138 /** Function called by the port when the bus is receiving a Timing
141 Bus::recvTiming(Packet
*pkt
)
144 DPRINTF(Bus
, "recvTiming: packet src %d dest %d addr 0x%x cmd %s\n",
145 pkt
->getSrc(), pkt
->getDest(), pkt
->getAddr(), pkt
->cmdString());
148 if (pkt
->getSrc() == defaultId
)
149 pktPort
= defaultPort
;
150 else pktPort
= interfaces
[pkt
->getSrc()];
152 // If the bus is busy, or other devices are in line ahead of the current
153 // one, put this device on the retry list.
154 if (tickNextIdle
> curTick
||
155 (retryList
.size() && (!inRetry
|| pktPort
!= retryList
.front()))) {
156 addToRetryList(pktPort
);
160 short dest
= pkt
->getDest();
161 if (dest
== Packet::Broadcast
) {
162 if (timingSnoop(pkt
)) {
163 pkt
->flags
|= SNOOP_COMMIT
;
164 bool success
= timingSnoop(pkt
);
166 if (pkt
->flags
& SATISFIED
) {
167 //Cache-Cache transfer occuring
169 retryList
.front()->onRetryList(false);
170 retryList
.pop_front();
176 port
= findPort(pkt
->getAddr(), pkt
->getSrc());
178 //Snoop didn't succeed
179 DPRINTF(Bus
, "Adding a retry to RETRY list %i\n", pktPort
);
180 addToRetryList(pktPort
);
184 assert(dest
>= 0 && dest
< interfaces
.size());
185 assert(dest
!= pkt
->getSrc()); // catch infinite loops
186 port
= interfaces
[dest
];
191 if (port
->sendTiming(pkt
)) {
192 // Packet was successfully sent. Return true.
193 // Also take care of retries
195 DPRINTF(Bus
, "Remove retry from list %i\n", retryList
.front());
196 retryList
.front()->onRetryList(false);
197 retryList
.pop_front();
203 // Packet not successfully sent. Leave or put it on the retry list.
204 DPRINTF(Bus
, "Adding a retry to RETRY list %i\n", pktPort
);
205 addToRetryList(pktPort
);
210 Bus::recvRetry(int id
)
212 DPRINTF(Bus
, "Received a retry\n");
213 // If there's anything waiting, and the bus isn't busy...
214 if (retryList
.size() && curTick
>= tickNextIdle
) {
215 //retryingPort = retryList.front();
217 DPRINTF(Bus
, "Sending a retry\n");
218 retryList
.front()->sendRetry();
219 // If inRetry is still true, sendTiming wasn't called
222 retryList
.front()->onRetryList(false);
223 retryList
.pop_front();
226 //Bring tickNextIdle up to the present
227 while (tickNextIdle
< curTick
)
228 tickNextIdle
+= clock
;
230 //Burn a cycle for the missed grant.
231 tickNextIdle
+= clock
;
233 if (!busIdle
.scheduled()) {
234 busIdle
.schedule(tickNextIdle
);
236 busIdle
.reschedule(tickNextIdle
);
243 Bus::findPort(Addr addr
, int id
)
245 /* An interval tree would be a better way to do this. --ali. */
251 while (i
< portList
.size() && !found
)
253 if (portList
[i
].range
== addr
) {
254 dest_id
= portList
[i
].portId
;
256 DPRINTF(Bus
, " found addr %#llx on device %d\n", addr
, dest_id
);
261 // Check if this matches the default range
263 for (iter
= defaultRange
.begin(); iter
!= defaultRange
.end(); iter
++) {
265 DPRINTF(Bus
, " found addr %#llx on default\n", addr
);
269 panic("Unable to find destination for addr: %#llx", addr
);
273 // we shouldn't be sending this back to where it came from
274 assert(dest_id
!= id
);
276 return interfaces
[dest_id
];
280 Bus::findSnoopPorts(Addr addr
, int id
)
284 std::vector
<int> ports
;
286 while (i
< portSnoopList
.size())
288 if (portSnoopList
[i
].range
== addr
&& portSnoopList
[i
].portId
!= id
) {
289 //Careful to not overlap ranges
290 //or snoop will be called more than once on the port
291 ports
.push_back(portSnoopList
[i
].portId
);
292 // DPRINTF(Bus, " found snoop addr %#llx on device%d\n", addr,
293 // portSnoopList[i].portId);
301 Bus::atomicSnoop(Packet
*pkt
)
303 std::vector
<int> ports
= findSnoopPorts(pkt
->getAddr(), pkt
->getSrc());
304 Tick response_time
= 0;
306 while (!ports
.empty())
308 Tick response
= interfaces
[ports
.back()]->sendAtomic(pkt
);
310 assert(!response_time
); //Multiple responders
311 response_time
= response
;
315 return response_time
;
319 Bus::functionalSnoop(Packet
*pkt
)
321 std::vector
<int> ports
= findSnoopPorts(pkt
->getAddr(), pkt
->getSrc());
323 while (!ports
.empty())
325 interfaces
[ports
.back()]->sendFunctional(pkt
);
331 Bus::timingSnoop(Packet
*pkt
)
333 std::vector
<int> ports
= findSnoopPorts(pkt
->getAddr(), pkt
->getSrc());
336 while (!ports
.empty() && success
)
338 success
= interfaces
[ports
.back()]->sendTiming(pkt
);
346 /** Function called by the port when the bus is receiving a Atomic
349 Bus::recvAtomic(Packet
*pkt
)
351 DPRINTF(Bus
, "recvAtomic: packet src %d dest %d addr 0x%x cmd %s\n",
352 pkt
->getSrc(), pkt
->getDest(), pkt
->getAddr(), pkt
->cmdString());
353 assert(pkt
->getDest() == Packet::Broadcast
);
354 Tick snoopTime
= atomicSnoop(pkt
);
356 return snoopTime
; //Snoop satisfies it
358 return findPort(pkt
->getAddr(), pkt
->getSrc())->sendAtomic(pkt
);
361 /** Function called by the port when the bus is receiving a Functional
364 Bus::recvFunctional(Packet
*pkt
)
366 DPRINTF(Bus
, "recvFunctional: packet src %d dest %d addr 0x%x cmd %s\n",
367 pkt
->getSrc(), pkt
->getDest(), pkt
->getAddr(), pkt
->cmdString());
368 assert(pkt
->getDest() == Packet::Broadcast
);
369 functionalSnoop(pkt
);
370 findPort(pkt
->getAddr(), pkt
->getSrc())->sendFunctional(pkt
);
373 /** Function called by the port when the bus is receiving a status change.*/
375 Bus::recvStatusChange(Port::Status status
, int id
)
377 AddrRangeList ranges
;
378 AddrRangeList snoops
;
382 assert(status
== Port::RangeChange
&&
383 "The other statuses need to be implemented.");
385 DPRINTF(BusAddrRanges
, "received RangeChange from device id %d\n", id
);
387 if (id
== defaultId
) {
388 defaultRange
.clear();
389 defaultPort
->getPeerAddressRanges(ranges
, snoops
);
390 assert(snoops
.size() == 0);
391 for(iter
= ranges
.begin(); iter
!= ranges
.end(); iter
++) {
392 defaultRange
.push_back(*iter
);
393 DPRINTF(BusAddrRanges
, "Adding range %#llx - %#llx for default range\n",
394 iter
->start
, iter
->end
);
398 assert((id
< interfaces
.size() && id
>= 0) || id
== defaultId
);
399 Port
*port
= interfaces
[id
];
400 std::vector
<DevMap
>::iterator portIter
;
401 std::vector
<DevMap
>::iterator snoopIter
;
403 // Clean out any previously existent ids
404 for (portIter
= portList
.begin(); portIter
!= portList
.end(); ) {
405 if (portIter
->portId
== id
)
406 portIter
= portList
.erase(portIter
);
411 for (snoopIter
= portSnoopList
.begin(); snoopIter
!= portSnoopList
.end(); ) {
412 if (snoopIter
->portId
== id
)
413 snoopIter
= portSnoopList
.erase(snoopIter
);
418 port
->getPeerAddressRanges(ranges
, snoops
);
420 for(iter
= snoops
.begin(); iter
!= snoops
.end(); iter
++) {
425 DPRINTF(BusAddrRanges
, "Adding snoop range %#llx - %#llx for id %d\n",
426 dm
.range
.start
, dm
.range
.end
, id
);
427 portSnoopList
.push_back(dm
);
430 for(iter
= ranges
.begin(); iter
!= ranges
.end(); iter
++) {
435 DPRINTF(BusAddrRanges
, "Adding range %#llx - %#llx for id %d\n",
436 dm
.range
.start
, dm
.range
.end
, id
);
437 portList
.push_back(dm
);
440 DPRINTF(MMU
, "port list has %d entries\n", portList
.size());
442 // tell all our peers that our address range has changed.
443 // Don't tell the device that caused this change, it already knows
444 for (x
= 0; x
< interfaces
.size(); x
++)
446 interfaces
[x
]->sendStatusChange(Port::RangeChange
);
448 if (id
!= defaultId
&& defaultPort
)
449 defaultPort
->sendStatusChange(Port::RangeChange
);
453 Bus::addressRanges(AddrRangeList
&resp
, AddrRangeList
&snoop
, int id
)
455 std::vector
<DevMap
>::iterator portIter
;
456 AddrRangeIter dflt_iter
;
462 DPRINTF(BusAddrRanges
, "received address range request, returning:\n");
464 for (dflt_iter
= defaultRange
.begin(); dflt_iter
!= defaultRange
.end();
466 resp
.push_back(*dflt_iter
);
467 DPRINTF(BusAddrRanges
, " -- %#llx : %#llx\n",dflt_iter
->start
,
470 for (portIter
= portList
.begin(); portIter
!= portList
.end(); portIter
++) {
472 for (dflt_iter
= defaultRange
.begin(); dflt_iter
!= defaultRange
.end();
474 if ((portIter
->range
.start
< dflt_iter
->start
&&
475 portIter
->range
.end
>= dflt_iter
->start
) ||
476 (portIter
->range
.start
< dflt_iter
->end
&&
477 portIter
->range
.end
>= dflt_iter
->end
))
478 fatal("Devices can not set ranges that itersect the default set\
479 but are not a subset of the default set.\n");
480 if (portIter
->range
.start
>= dflt_iter
->start
&&
481 portIter
->range
.end
<= dflt_iter
->end
) {
483 DPRINTF(BusAddrRanges
, " -- %#llx : %#llx is a SUBSET\n",
484 portIter
->range
.start
, portIter
->range
.end
);
487 if (portIter
->portId
!= id
&& !subset
) {
488 resp
.push_back(portIter
->range
);
489 DPRINTF(BusAddrRanges
, " -- %#llx : %#llx\n",
490 portIter
->range
.start
, portIter
->range
.end
);
495 BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bus
)
501 END_DECLARE_SIM_OBJECT_PARAMS(Bus
)
503 BEGIN_INIT_SIM_OBJECT_PARAMS(Bus
)
504 INIT_PARAM(bus_id
, "a globally unique bus id"),
505 INIT_PARAM(clock
, "bus clock speed"),
506 INIT_PARAM(width
, "width of the bus (bits)")
507 END_INIT_SIM_OBJECT_PARAMS(Bus
)
509 CREATE_SIM_OBJECT(Bus
)
511 return new Bus(getInstanceName(), bus_id
, clock
, width
);
514 REGISTER_SIM_OBJECT("Bus", Bus
)