1/*
2 * Copyright (c) 2013 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
9 * licensed hereunder. You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2005 The Regents of The University of Michigan
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright

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146{
147 DPRINTF(HWPrefetch, "Requesting a hw_pf to issue\n");
148
149 if (pf.empty()) {
150 DPRINTF(HWPrefetch, "No HW_PF found\n");
151 return NULL;
152 }
153
154 PacketPtr pkt = pf.begin()->pkt;
155 while (!pf.empty()) {
156 pkt = pf.begin()->pkt;
157 pf.pop_front();
158
159 Addr blk_addr = pkt->getAddr() & ~(Addr)(blkSize-1);
160
161 if (!inCache(blk_addr) && !inMissQueue(blk_addr))
162 // we found a prefetch, return it
163 break;
164

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175 pfIssued++;
176 assert(pkt != NULL);
177 DPRINTF(HWPrefetch, "returning 0x%x\n", pkt->getAddr());
178 return pkt;
179}
180
181
182Tick
183BasePrefetcher::notify(PacketPtr &pkt, Tick tick)
184{
185 if (!pkt->req->isUncacheable() && !(pkt->req->isInstFetch() && onlyData)) {
186 // Calculate the blk address
187 Addr blk_addr = pkt->getAddr() & ~(Addr)(blkSize-1);
188
189 // Check if miss is in pfq, if so remove it
190 std::list<DeferredPacket>::iterator iter = inPrefetch(blk_addr);
191 if (iter != pf.end()) {
192 DPRINTF(HWPrefetch, "Saw a miss to a queued prefetch addr: "
193 "0x%x, removing it\n", blk_addr);
194 pfRemovedMSHR++;
195 delete iter->pkt->req;
196 delete iter->pkt;
197 iter = pf.erase(iter);
198 if (pf.empty())
199 cache->deassertMemSideBusRequest(BaseCache::Request_PF);
200 }
201
202 // Remove anything in queue with delay older than time
203 // since everything is inserted in time order, start from end
204 // and work until pf.empty() or time is earlier
205 // This is done to emulate Aborting the previous work on a new miss
206 // Needed for serial calculators like GHB
207 if (serialSquash) {
208 iter = pf.end();
209 if (iter != pf.begin())
210 iter--;
211 while (!pf.empty() && iter->tick >= tick) {
212 pfSquashed++;
213 DPRINTF(HWPrefetch, "Squashing old prefetch addr: 0x%x\n",
214 iter->pkt->getAddr());
215 delete iter->pkt->req;
216 delete iter->pkt;
217 iter = pf.erase(iter);
218 if (iter != pf.begin())
219 iter--;
220 }
221 if (pf.empty())
222 cache->deassertMemSideBusRequest(BaseCache::Request_PF);
223 }
224

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248 // create a prefetch memreq
249 Request *prefetchReq = new Request(*addrIter, blkSize, 0, masterId);
250 PacketPtr prefetch =
251 new Packet(prefetchReq, MemCmd::HardPFReq);
252 prefetch->allocate();
253 prefetch->req->setThreadContext(pkt->req->contextId(),
254 pkt->req->threadId());
255
256 // We just remove the head if we are full
257 if (pf.size() == size) {
258 pfRemovedFull++;
259 PacketPtr old_pkt = pf.begin()->pkt;
260 DPRINTF(HWPrefetch, "Prefetch queue full, "
261 "removing oldest 0x%x\n", old_pkt->getAddr());
262 delete old_pkt->req;
263 delete old_pkt;
264 pf.pop_front();
265 }
266
267 pf.push_back(DeferredPacket(tick + clockPeriod() * *delayIter,
268 prefetch));
269 }
270 }
271
272 return pf.empty() ? 0 : pf.front().tick;
273}
274
275std::list<BasePrefetcher::DeferredPacket>::iterator
276BasePrefetcher::inPrefetch(Addr address)
277{
278 // Guaranteed to only be one match, we always check before inserting
279 std::list<DeferredPacket>::iterator iter;
280 for (iter = pf.begin(); iter != pf.end(); iter++) {
281 if ((iter->pkt->getAddr() & ~(Addr)(blkSize-1)) == address) {
282 return iter;
283 }
284 }
285 return pf.end();
286}
287
288bool
289BasePrefetcher::samePage(Addr a, Addr b)
290{
291 return roundDown(a, TheISA::VMPageSize) == roundDown(b, TheISA::VMPageSize);
292}
293
294