1/*
2 * Copyright (c) 2013-2015 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

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169std::pair<SnoopFilter::SnoopList, Cycles>
170SnoopFilter::lookupSnoop(const Packet* cpkt)
171{
172 DPRINTF(SnoopFilter, "%s: packet addr 0x%x cmd %s\n",
173 __func__, cpkt->getAddr(), cpkt->cmdString());
174
175 assert(cpkt->isRequest());
176
177 Addr line_addr = cpkt->getBlockAddr(linesize);
178 auto sf_it = cachedLocations.find(line_addr);
179 bool is_hit = (sf_it != cachedLocations.end());
180
181 panic_if(!is_hit && (cachedLocations.size() >= maxEntryCount),
182 "snoop filter exceeded capacity of %d cache blocks\n",
183 maxEntryCount);
184
185 // If the snoop filter has no entry, simply return a NULL
186 // portlist, there is no point creating an entry only to remove it
187 // later
188 if (!is_hit)
189 return snoopDown(lookupLatency);
190
191 SnoopItem& sf_item = sf_it->second;
192
193 DPRINTF(SnoopFilter, "%s: old SF value %x.%x\n",
194 __func__, sf_item.requested, sf_item.holder);
195
196 SnoopMask interested = (sf_item.holder | sf_item.requested);
197
198 totSnoops++;
199 // Single bit set -> value is a power of two
200 if (isPow2(interested))
201 hitSingleSnoops++;
202 else
203 hitMultiSnoops++;
204
205 // ReadEx and Writes require both invalidation and exlusivity, while reads
206 // require neither. Writebacks on the other hand require exclusivity but
207 // not the invalidation. Previously Writebacks did not generate upward
208 // snoops so this was never an aissue. Now that Writebacks generate snoops
209 // we need to special case for Writebacks.
210 assert(cpkt->cmd == MemCmd::Writeback || cpkt->req->isUncacheable() ||
211 (cpkt->isInvalidate() == cpkt->needsExclusive()));
212 if (cpkt->isInvalidate() && !sf_item.requested) {

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281void
282SnoopFilter::updateSnoopForward(const Packet* cpkt,
283 const SlavePort& rsp_port, const MasterPort& req_port)
284{
285 DPRINTF(SnoopFilter, "%s: packet rsp %s req %s addr 0x%x cmd %s\n",
286 __func__, rsp_port.name(), req_port.name(), cpkt->getAddr(),
287 cpkt->cmdString());
288
289 assert(cpkt->isResponse());
290 assert(cpkt->memInhibitAsserted());
291
292 Addr line_addr = cpkt->getBlockAddr(linesize);
293 auto sf_it = cachedLocations.find(line_addr);
294 bool is_hit = sf_it != cachedLocations.end();
295
296 // Nothing to do if it is not a hit
297 if (!is_hit)
298 return;
299
300 SnoopItem& sf_item = sf_it->second;
301
302 DPRINTF(SnoopFilter, "%s: old SF value %x.%x\n",
303 __func__, sf_item.requested, sf_item.holder);
304
305 // Remote (to this snoop filter) snoops update the filter
306 // already when they arrive from below, because we may not see
307 // any response.
308 if (cpkt->needsExclusive()) {
309 // If the request to this snoop response hit an in-flight
310 // transaction,
311 // the holder was not reset -> no assertion & do that here, now!
312 //assert(sf_item.holder == 0);
313 sf_item.holder = 0;
314 }
315 DPRINTF(SnoopFilter, "%s: new SF value %x.%x\n",
316 __func__, sf_item.requested, sf_item.holder);
317 eraseIfNullEntry(sf_it);
318
319}
320
321void
322SnoopFilter::updateResponse(const Packet* cpkt, const SlavePort& slave_port)
323{
324 DPRINTF(SnoopFilter, "%s: packet src %s addr 0x%x cmd %s\n",
325 __func__, slave_port.name(), cpkt->getAddr(), cpkt->cmdString());
326

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