dram_ctrl.cc revision 13784:1941dc118243
1/*
2 * Copyright (c) 2010-2018 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) 2013 Amin Farmahini-Farahani
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
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Andreas Hansson
41 *          Ani Udipi
42 *          Neha Agarwal
43 *          Omar Naji
44 *          Wendy Elsasser
45 *          Radhika Jagtap
46 */
47
48#include "mem/dram_ctrl.hh"
49
50#include "base/bitfield.hh"
51#include "base/trace.hh"
52#include "debug/DRAM.hh"
53#include "debug/DRAMPower.hh"
54#include "debug/DRAMState.hh"
55#include "debug/Drain.hh"
56#include "debug/QOS.hh"
57#include "sim/system.hh"
58
59using namespace std;
60using namespace Data;
61
62DRAMCtrl::DRAMCtrl(const DRAMCtrlParams* p) :
63    QoS::MemCtrl(p),
64    port(name() + ".port", *this), isTimingMode(false),
65    retryRdReq(false), retryWrReq(false),
66    nextReqEvent([this]{ processNextReqEvent(); }, name()),
67    respondEvent([this]{ processRespondEvent(); }, name()),
68    deviceSize(p->device_size),
69    deviceBusWidth(p->device_bus_width), burstLength(p->burst_length),
70    deviceRowBufferSize(p->device_rowbuffer_size),
71    devicesPerRank(p->devices_per_rank),
72    burstSize((devicesPerRank * burstLength * deviceBusWidth) / 8),
73    rowBufferSize(devicesPerRank * deviceRowBufferSize),
74    columnsPerRowBuffer(rowBufferSize / burstSize),
75    columnsPerStripe(range.interleaved() ? range.granularity() / burstSize : 1),
76    ranksPerChannel(p->ranks_per_channel),
77    bankGroupsPerRank(p->bank_groups_per_rank),
78    bankGroupArch(p->bank_groups_per_rank > 0),
79    banksPerRank(p->banks_per_rank), channels(p->channels), rowsPerBank(0),
80    readBufferSize(p->read_buffer_size),
81    writeBufferSize(p->write_buffer_size),
82    writeHighThreshold(writeBufferSize * p->write_high_thresh_perc / 100.0),
83    writeLowThreshold(writeBufferSize * p->write_low_thresh_perc / 100.0),
84    minWritesPerSwitch(p->min_writes_per_switch),
85    writesThisTime(0), readsThisTime(0),
86    tCK(p->tCK), tRTW(p->tRTW), tCS(p->tCS), tBURST(p->tBURST),
87    tCCD_L_WR(p->tCCD_L_WR),
88    tCCD_L(p->tCCD_L), tRCD(p->tRCD), tCL(p->tCL), tRP(p->tRP), tRAS(p->tRAS),
89    tWR(p->tWR), tRTP(p->tRTP), tRFC(p->tRFC), tREFI(p->tREFI), tRRD(p->tRRD),
90    tRRD_L(p->tRRD_L), tXAW(p->tXAW), tXP(p->tXP), tXS(p->tXS),
91    activationLimit(p->activation_limit), rankToRankDly(tCS + tBURST),
92    wrToRdDly(tCL + tBURST + p->tWTR), rdToWrDly(tRTW + tBURST),
93    memSchedPolicy(p->mem_sched_policy), addrMapping(p->addr_mapping),
94    pageMgmt(p->page_policy),
95    maxAccessesPerRow(p->max_accesses_per_row),
96    frontendLatency(p->static_frontend_latency),
97    backendLatency(p->static_backend_latency),
98    nextBurstAt(0), prevArrival(0),
99    nextReqTime(0), activeRank(0), timeStampOffset(0),
100    lastStatsResetTick(0)
101{
102    // sanity check the ranks since we rely on bit slicing for the
103    // address decoding
104    fatal_if(!isPowerOf2(ranksPerChannel), "DRAM rank count of %d is not "
105             "allowed, must be a power of two\n", ranksPerChannel);
106
107    fatal_if(!isPowerOf2(burstSize), "DRAM burst size %d is not allowed, "
108             "must be a power of two\n", burstSize);
109    readQueue.resize(p->qos_priorities);
110    writeQueue.resize(p->qos_priorities);
111
112
113    for (int i = 0; i < ranksPerChannel; i++) {
114        Rank* rank = new Rank(*this, p, i);
115        ranks.push_back(rank);
116    }
117
118    // perform a basic check of the write thresholds
119    if (p->write_low_thresh_perc >= p->write_high_thresh_perc)
120        fatal("Write buffer low threshold %d must be smaller than the "
121              "high threshold %d\n", p->write_low_thresh_perc,
122              p->write_high_thresh_perc);
123
124    // determine the rows per bank by looking at the total capacity
125    uint64_t capacity = ULL(1) << ceilLog2(AbstractMemory::size());
126
127    // determine the dram actual capacity from the DRAM config in Mbytes
128    uint64_t deviceCapacity = deviceSize / (1024 * 1024) * devicesPerRank *
129        ranksPerChannel;
130
131    // if actual DRAM size does not match memory capacity in system warn!
132    if (deviceCapacity != capacity / (1024 * 1024))
133        warn("DRAM device capacity (%d Mbytes) does not match the "
134             "address range assigned (%d Mbytes)\n", deviceCapacity,
135             capacity / (1024 * 1024));
136
137    DPRINTF(DRAM, "Memory capacity %lld (%lld) bytes\n", capacity,
138            AbstractMemory::size());
139
140    DPRINTF(DRAM, "Row buffer size %d bytes with %d columns per row buffer\n",
141            rowBufferSize, columnsPerRowBuffer);
142
143    rowsPerBank = capacity / (rowBufferSize * banksPerRank * ranksPerChannel);
144
145    // some basic sanity checks
146    if (tREFI <= tRP || tREFI <= tRFC) {
147        fatal("tREFI (%d) must be larger than tRP (%d) and tRFC (%d)\n",
148              tREFI, tRP, tRFC);
149    }
150
151    // basic bank group architecture checks ->
152    if (bankGroupArch) {
153        // must have at least one bank per bank group
154        if (bankGroupsPerRank > banksPerRank) {
155            fatal("banks per rank (%d) must be equal to or larger than "
156                  "banks groups per rank (%d)\n",
157                  banksPerRank, bankGroupsPerRank);
158        }
159        // must have same number of banks in each bank group
160        if ((banksPerRank % bankGroupsPerRank) != 0) {
161            fatal("Banks per rank (%d) must be evenly divisible by bank groups "
162                  "per rank (%d) for equal banks per bank group\n",
163                  banksPerRank, bankGroupsPerRank);
164        }
165        // tCCD_L should be greater than minimal, back-to-back burst delay
166        if (tCCD_L <= tBURST) {
167            fatal("tCCD_L (%d) should be larger than tBURST (%d) when "
168                  "bank groups per rank (%d) is greater than 1\n",
169                  tCCD_L, tBURST, bankGroupsPerRank);
170        }
171        // tCCD_L_WR should be greater than minimal, back-to-back burst delay
172        if (tCCD_L_WR <= tBURST) {
173            fatal("tCCD_L_WR (%d) should be larger than tBURST (%d) when "
174                  "bank groups per rank (%d) is greater than 1\n",
175                  tCCD_L_WR, tBURST, bankGroupsPerRank);
176        }
177        // tRRD_L is greater than minimal, same bank group ACT-to-ACT delay
178        // some datasheets might specify it equal to tRRD
179        if (tRRD_L < tRRD) {
180            fatal("tRRD_L (%d) should be larger than tRRD (%d) when "
181                  "bank groups per rank (%d) is greater than 1\n",
182                  tRRD_L, tRRD, bankGroupsPerRank);
183        }
184    }
185
186}
187
188void
189DRAMCtrl::init()
190{
191    MemCtrl::init();
192
193   if (!port.isConnected()) {
194        fatal("DRAMCtrl %s is unconnected!\n", name());
195    } else {
196        port.sendRangeChange();
197    }
198
199    // a bit of sanity checks on the interleaving, save it for here to
200    // ensure that the system pointer is initialised
201    if (range.interleaved()) {
202        if (channels != range.stripes())
203            fatal("%s has %d interleaved address stripes but %d channel(s)\n",
204                  name(), range.stripes(), channels);
205
206        if (addrMapping == Enums::RoRaBaChCo) {
207            if (rowBufferSize != range.granularity()) {
208                fatal("Channel interleaving of %s doesn't match RoRaBaChCo "
209                      "address map\n", name());
210            }
211        } else if (addrMapping == Enums::RoRaBaCoCh ||
212                   addrMapping == Enums::RoCoRaBaCh) {
213            // for the interleavings with channel bits in the bottom,
214            // if the system uses a channel striping granularity that
215            // is larger than the DRAM burst size, then map the
216            // sequential accesses within a stripe to a number of
217            // columns in the DRAM, effectively placing some of the
218            // lower-order column bits as the least-significant bits
219            // of the address (above the ones denoting the burst size)
220            assert(columnsPerStripe >= 1);
221
222            // channel striping has to be done at a granularity that
223            // is equal or larger to a cache line
224            if (system()->cacheLineSize() > range.granularity()) {
225                fatal("Channel interleaving of %s must be at least as large "
226                      "as the cache line size\n", name());
227            }
228
229            // ...and equal or smaller than the row-buffer size
230            if (rowBufferSize < range.granularity()) {
231                fatal("Channel interleaving of %s must be at most as large "
232                      "as the row-buffer size\n", name());
233            }
234            // this is essentially the check above, so just to be sure
235            assert(columnsPerStripe <= columnsPerRowBuffer);
236        }
237    }
238}
239
240void
241DRAMCtrl::startup()
242{
243    // remember the memory system mode of operation
244    isTimingMode = system()->isTimingMode();
245
246    if (isTimingMode) {
247        // timestamp offset should be in clock cycles for DRAMPower
248        timeStampOffset = divCeil(curTick(), tCK);
249
250        // update the start tick for the precharge accounting to the
251        // current tick
252        for (auto r : ranks) {
253            r->startup(curTick() + tREFI - tRP);
254        }
255
256        // shift the bus busy time sufficiently far ahead that we never
257        // have to worry about negative values when computing the time for
258        // the next request, this will add an insignificant bubble at the
259        // start of simulation
260        nextBurstAt = curTick() + tRP + tRCD;
261    }
262}
263
264Tick
265DRAMCtrl::recvAtomic(PacketPtr pkt)
266{
267    DPRINTF(DRAM, "recvAtomic: %s 0x%x\n", pkt->cmdString(), pkt->getAddr());
268
269    panic_if(pkt->cacheResponding(), "Should not see packets where cache "
270             "is responding");
271
272    // do the actual memory access and turn the packet into a response
273    access(pkt);
274
275    Tick latency = 0;
276    if (pkt->hasData()) {
277        // this value is not supposed to be accurate, just enough to
278        // keep things going, mimic a closed page
279        latency = tRP + tRCD + tCL;
280    }
281    return latency;
282}
283
284bool
285DRAMCtrl::readQueueFull(unsigned int neededEntries) const
286{
287    DPRINTF(DRAM, "Read queue limit %d, current size %d, entries needed %d\n",
288            readBufferSize, totalReadQueueSize + respQueue.size(),
289            neededEntries);
290
291    auto rdsize_new = totalReadQueueSize + respQueue.size() + neededEntries;
292    return rdsize_new > readBufferSize;
293}
294
295bool
296DRAMCtrl::writeQueueFull(unsigned int neededEntries) const
297{
298    DPRINTF(DRAM, "Write queue limit %d, current size %d, entries needed %d\n",
299            writeBufferSize, totalWriteQueueSize, neededEntries);
300
301    auto wrsize_new = (totalWriteQueueSize + neededEntries);
302    return  wrsize_new > writeBufferSize;
303}
304
305DRAMCtrl::DRAMPacket*
306DRAMCtrl::decodeAddr(PacketPtr pkt, Addr dramPktAddr, unsigned size,
307                       bool isRead)
308{
309    // decode the address based on the address mapping scheme, with
310    // Ro, Ra, Co, Ba and Ch denoting row, rank, column, bank and
311    // channel, respectively
312    uint8_t rank;
313    uint8_t bank;
314    // use a 64-bit unsigned during the computations as the row is
315    // always the top bits, and check before creating the DRAMPacket
316    uint64_t row;
317
318    // truncate the address to a DRAM burst, which makes it unique to
319    // a specific column, row, bank, rank and channel
320    Addr addr = dramPktAddr / burstSize;
321
322    // we have removed the lowest order address bits that denote the
323    // position within the column
324    if (addrMapping == Enums::RoRaBaChCo) {
325        // the lowest order bits denote the column to ensure that
326        // sequential cache lines occupy the same row
327        addr = addr / columnsPerRowBuffer;
328
329        // take out the channel part of the address
330        addr = addr / channels;
331
332        // after the channel bits, get the bank bits to interleave
333        // over the banks
334        bank = addr % banksPerRank;
335        addr = addr / banksPerRank;
336
337        // after the bank, we get the rank bits which thus interleaves
338        // over the ranks
339        rank = addr % ranksPerChannel;
340        addr = addr / ranksPerChannel;
341
342        // lastly, get the row bits, no need to remove them from addr
343        row = addr % rowsPerBank;
344    } else if (addrMapping == Enums::RoRaBaCoCh) {
345        // take out the lower-order column bits
346        addr = addr / columnsPerStripe;
347
348        // take out the channel part of the address
349        addr = addr / channels;
350
351        // next, the higher-order column bites
352        addr = addr / (columnsPerRowBuffer / columnsPerStripe);
353
354        // after the column bits, we get the bank bits to interleave
355        // over the banks
356        bank = addr % banksPerRank;
357        addr = addr / banksPerRank;
358
359        // after the bank, we get the rank bits which thus interleaves
360        // over the ranks
361        rank = addr % ranksPerChannel;
362        addr = addr / ranksPerChannel;
363
364        // lastly, get the row bits, no need to remove them from addr
365        row = addr % rowsPerBank;
366    } else if (addrMapping == Enums::RoCoRaBaCh) {
367        // optimise for closed page mode and utilise maximum
368        // parallelism of the DRAM (at the cost of power)
369
370        // take out the lower-order column bits
371        addr = addr / columnsPerStripe;
372
373        // take out the channel part of the address, not that this has
374        // to match with how accesses are interleaved between the
375        // controllers in the address mapping
376        addr = addr / channels;
377
378        // start with the bank bits, as this provides the maximum
379        // opportunity for parallelism between requests
380        bank = addr % banksPerRank;
381        addr = addr / banksPerRank;
382
383        // next get the rank bits
384        rank = addr % ranksPerChannel;
385        addr = addr / ranksPerChannel;
386
387        // next, the higher-order column bites
388        addr = addr / (columnsPerRowBuffer / columnsPerStripe);
389
390        // lastly, get the row bits, no need to remove them from addr
391        row = addr % rowsPerBank;
392    } else
393        panic("Unknown address mapping policy chosen!");
394
395    assert(rank < ranksPerChannel);
396    assert(bank < banksPerRank);
397    assert(row < rowsPerBank);
398    assert(row < Bank::NO_ROW);
399
400    DPRINTF(DRAM, "Address: %lld Rank %d Bank %d Row %d\n",
401            dramPktAddr, rank, bank, row);
402
403    // create the corresponding DRAM packet with the entry time and
404    // ready time set to the current tick, the latter will be updated
405    // later
406    uint16_t bank_id = banksPerRank * rank + bank;
407    return new DRAMPacket(pkt, isRead, rank, bank, row, bank_id, dramPktAddr,
408                          size, ranks[rank]->banks[bank], *ranks[rank]);
409}
410
411void
412DRAMCtrl::addToReadQueue(PacketPtr pkt, unsigned int pktCount)
413{
414    // only add to the read queue here. whenever the request is
415    // eventually done, set the readyTime, and call schedule()
416    assert(!pkt->isWrite());
417
418    assert(pktCount != 0);
419
420    // if the request size is larger than burst size, the pkt is split into
421    // multiple DRAM packets
422    // Note if the pkt starting address is not aligened to burst size, the
423    // address of first DRAM packet is kept unaliged. Subsequent DRAM packets
424    // are aligned to burst size boundaries. This is to ensure we accurately
425    // check read packets against packets in write queue.
426    Addr addr = pkt->getAddr();
427    unsigned pktsServicedByWrQ = 0;
428    BurstHelper* burst_helper = NULL;
429    for (int cnt = 0; cnt < pktCount; ++cnt) {
430        unsigned size = std::min((addr | (burstSize - 1)) + 1,
431                        pkt->getAddr() + pkt->getSize()) - addr;
432        readPktSize[ceilLog2(size)]++;
433        readBursts++;
434        masterReadAccesses[pkt->masterId()]++;
435
436        // First check write buffer to see if the data is already at
437        // the controller
438        bool foundInWrQ = false;
439        Addr burst_addr = burstAlign(addr);
440        // if the burst address is not present then there is no need
441        // looking any further
442        if (isInWriteQueue.find(burst_addr) != isInWriteQueue.end()) {
443            for (const auto& vec : writeQueue) {
444                for (const auto& p : vec) {
445                    // check if the read is subsumed in the write queue
446                    // packet we are looking at
447                    if (p->addr <= addr &&
448                       ((addr + size) <= (p->addr + p->size))) {
449
450                        foundInWrQ = true;
451                        servicedByWrQ++;
452                        pktsServicedByWrQ++;
453                        DPRINTF(DRAM,
454                                "Read to addr %lld with size %d serviced by "
455                                "write queue\n",
456                                addr, size);
457                        bytesReadWrQ += burstSize;
458                        break;
459                    }
460                }
461            }
462        }
463
464        // If not found in the write q, make a DRAM packet and
465        // push it onto the read queue
466        if (!foundInWrQ) {
467
468            // Make the burst helper for split packets
469            if (pktCount > 1 && burst_helper == NULL) {
470                DPRINTF(DRAM, "Read to addr %lld translates to %d "
471                        "dram requests\n", pkt->getAddr(), pktCount);
472                burst_helper = new BurstHelper(pktCount);
473            }
474
475            DRAMPacket* dram_pkt = decodeAddr(pkt, addr, size, true);
476            dram_pkt->burstHelper = burst_helper;
477
478            assert(!readQueueFull(1));
479            rdQLenPdf[totalReadQueueSize + respQueue.size()]++;
480
481            DPRINTF(DRAM, "Adding to read queue\n");
482
483            readQueue[dram_pkt->qosValue()].push_back(dram_pkt);
484
485            ++dram_pkt->rankRef.readEntries;
486
487            // log packet
488            logRequest(MemCtrl::READ, pkt->masterId(), pkt->qosValue(),
489                       dram_pkt->addr, 1);
490
491            // Update stats
492            avgRdQLen = totalReadQueueSize + respQueue.size();
493        }
494
495        // Starting address of next dram pkt (aligend to burstSize boundary)
496        addr = (addr | (burstSize - 1)) + 1;
497    }
498
499    // If all packets are serviced by write queue, we send the repsonse back
500    if (pktsServicedByWrQ == pktCount) {
501        accessAndRespond(pkt, frontendLatency);
502        return;
503    }
504
505    // Update how many split packets are serviced by write queue
506    if (burst_helper != NULL)
507        burst_helper->burstsServiced = pktsServicedByWrQ;
508
509    // If we are not already scheduled to get a request out of the
510    // queue, do so now
511    if (!nextReqEvent.scheduled()) {
512        DPRINTF(DRAM, "Request scheduled immediately\n");
513        schedule(nextReqEvent, curTick());
514    }
515}
516
517void
518DRAMCtrl::addToWriteQueue(PacketPtr pkt, unsigned int pktCount)
519{
520    // only add to the write queue here. whenever the request is
521    // eventually done, set the readyTime, and call schedule()
522    assert(pkt->isWrite());
523
524    // if the request size is larger than burst size, the pkt is split into
525    // multiple DRAM packets
526    Addr addr = pkt->getAddr();
527    for (int cnt = 0; cnt < pktCount; ++cnt) {
528        unsigned size = std::min((addr | (burstSize - 1)) + 1,
529                        pkt->getAddr() + pkt->getSize()) - addr;
530        writePktSize[ceilLog2(size)]++;
531        writeBursts++;
532        masterWriteAccesses[pkt->masterId()]++;
533
534        // see if we can merge with an existing item in the write
535        // queue and keep track of whether we have merged or not
536        bool merged = isInWriteQueue.find(burstAlign(addr)) !=
537            isInWriteQueue.end();
538
539        // if the item was not merged we need to create a new write
540        // and enqueue it
541        if (!merged) {
542            DRAMPacket* dram_pkt = decodeAddr(pkt, addr, size, false);
543
544            assert(totalWriteQueueSize < writeBufferSize);
545            wrQLenPdf[totalWriteQueueSize]++;
546
547            DPRINTF(DRAM, "Adding to write queue\n");
548
549            writeQueue[dram_pkt->qosValue()].push_back(dram_pkt);
550            isInWriteQueue.insert(burstAlign(addr));
551
552            // log packet
553            logRequest(MemCtrl::WRITE, pkt->masterId(), pkt->qosValue(),
554                       dram_pkt->addr, 1);
555
556            assert(totalWriteQueueSize == isInWriteQueue.size());
557
558            // Update stats
559            avgWrQLen = totalWriteQueueSize;
560
561            // increment write entries of the rank
562            ++dram_pkt->rankRef.writeEntries;
563        } else {
564            DPRINTF(DRAM, "Merging write burst with existing queue entry\n");
565
566            // keep track of the fact that this burst effectively
567            // disappeared as it was merged with an existing one
568            mergedWrBursts++;
569        }
570
571        // Starting address of next dram pkt (aligend to burstSize boundary)
572        addr = (addr | (burstSize - 1)) + 1;
573    }
574
575    // we do not wait for the writes to be send to the actual memory,
576    // but instead take responsibility for the consistency here and
577    // snoop the write queue for any upcoming reads
578    // @todo, if a pkt size is larger than burst size, we might need a
579    // different front end latency
580    accessAndRespond(pkt, frontendLatency);
581
582    // If we are not already scheduled to get a request out of the
583    // queue, do so now
584    if (!nextReqEvent.scheduled()) {
585        DPRINTF(DRAM, "Request scheduled immediately\n");
586        schedule(nextReqEvent, curTick());
587    }
588}
589
590void
591DRAMCtrl::printQs() const
592{
593#if TRACING_ON
594    DPRINTF(DRAM, "===READ QUEUE===\n\n");
595    for (const auto& queue : readQueue) {
596        for (const auto& packet : queue) {
597            DPRINTF(DRAM, "Read %lu\n", packet->addr);
598        }
599    }
600
601    DPRINTF(DRAM, "\n===RESP QUEUE===\n\n");
602    for (const auto& packet : respQueue) {
603        DPRINTF(DRAM, "Response %lu\n", packet->addr);
604    }
605
606    DPRINTF(DRAM, "\n===WRITE QUEUE===\n\n");
607    for (const auto& queue : writeQueue) {
608        for (const auto& packet : queue) {
609            DPRINTF(DRAM, "Write %lu\n", packet->addr);
610        }
611    }
612#endif // TRACING_ON
613}
614
615bool
616DRAMCtrl::recvTimingReq(PacketPtr pkt)
617{
618    // This is where we enter from the outside world
619    DPRINTF(DRAM, "recvTimingReq: request %s addr %lld size %d\n",
620            pkt->cmdString(), pkt->getAddr(), pkt->getSize());
621
622    panic_if(pkt->cacheResponding(), "Should not see packets where cache "
623             "is responding");
624
625    panic_if(!(pkt->isRead() || pkt->isWrite()),
626             "Should only see read and writes at memory controller\n");
627
628    // Calc avg gap between requests
629    if (prevArrival != 0) {
630        totGap += curTick() - prevArrival;
631    }
632    prevArrival = curTick();
633
634
635    // Find out how many dram packets a pkt translates to
636    // If the burst size is equal or larger than the pkt size, then a pkt
637    // translates to only one dram packet. Otherwise, a pkt translates to
638    // multiple dram packets
639    unsigned size = pkt->getSize();
640    unsigned offset = pkt->getAddr() & (burstSize - 1);
641    unsigned int dram_pkt_count = divCeil(offset + size, burstSize);
642
643    // run the QoS scheduler and assign a QoS priority value to the packet
644    qosSchedule( { &readQueue, &writeQueue }, burstSize, pkt);
645
646    // check local buffers and do not accept if full
647    if (pkt->isRead()) {
648        assert(size != 0);
649        if (readQueueFull(dram_pkt_count)) {
650            DPRINTF(DRAM, "Read queue full, not accepting\n");
651            // remember that we have to retry this port
652            retryRdReq = true;
653            numRdRetry++;
654            return false;
655        } else {
656            addToReadQueue(pkt, dram_pkt_count);
657            readReqs++;
658            bytesReadSys += size;
659        }
660    } else {
661        assert(pkt->isWrite());
662        assert(size != 0);
663        if (writeQueueFull(dram_pkt_count)) {
664            DPRINTF(DRAM, "Write queue full, not accepting\n");
665            // remember that we have to retry this port
666            retryWrReq = true;
667            numWrRetry++;
668            return false;
669        } else {
670            addToWriteQueue(pkt, dram_pkt_count);
671            writeReqs++;
672            bytesWrittenSys += size;
673        }
674    }
675
676    return true;
677}
678
679void
680DRAMCtrl::processRespondEvent()
681{
682    DPRINTF(DRAM,
683            "processRespondEvent(): Some req has reached its readyTime\n");
684
685    DRAMPacket* dram_pkt = respQueue.front();
686
687    // if a read has reached its ready-time, decrement the number of reads
688    // At this point the packet has been handled and there is a possibility
689    // to switch to low-power mode if no other packet is available
690    --dram_pkt->rankRef.readEntries;
691    DPRINTF(DRAM, "number of read entries for rank %d is %d\n",
692            dram_pkt->rank, dram_pkt->rankRef.readEntries);
693
694    // counter should at least indicate one outstanding request
695    // for this read
696    assert(dram_pkt->rankRef.outstandingEvents > 0);
697    // read response received, decrement count
698    --dram_pkt->rankRef.outstandingEvents;
699
700    // at this moment should not have transitioned to a low-power state
701    assert((dram_pkt->rankRef.pwrState != PWR_SREF) &&
702           (dram_pkt->rankRef.pwrState != PWR_PRE_PDN) &&
703           (dram_pkt->rankRef.pwrState != PWR_ACT_PDN));
704
705    // track if this is the last packet before idling
706    // and that there are no outstanding commands to this rank
707    if (dram_pkt->rankRef.isQueueEmpty() &&
708        dram_pkt->rankRef.outstandingEvents == 0) {
709        // verify that there are no events scheduled
710        assert(!dram_pkt->rankRef.activateEvent.scheduled());
711        assert(!dram_pkt->rankRef.prechargeEvent.scheduled());
712
713        // if coming from active state, schedule power event to
714        // active power-down else go to precharge power-down
715        DPRINTF(DRAMState, "Rank %d sleep at tick %d; current power state is "
716                "%d\n", dram_pkt->rank, curTick(), dram_pkt->rankRef.pwrState);
717
718        // default to ACT power-down unless already in IDLE state
719        // could be in IDLE if PRE issued before data returned
720        PowerState next_pwr_state = PWR_ACT_PDN;
721        if (dram_pkt->rankRef.pwrState == PWR_IDLE) {
722            next_pwr_state = PWR_PRE_PDN;
723        }
724
725        dram_pkt->rankRef.powerDownSleep(next_pwr_state, curTick());
726    }
727
728    if (dram_pkt->burstHelper) {
729        // it is a split packet
730        dram_pkt->burstHelper->burstsServiced++;
731        if (dram_pkt->burstHelper->burstsServiced ==
732            dram_pkt->burstHelper->burstCount) {
733            // we have now serviced all children packets of a system packet
734            // so we can now respond to the requester
735            // @todo we probably want to have a different front end and back
736            // end latency for split packets
737            accessAndRespond(dram_pkt->pkt, frontendLatency + backendLatency);
738            delete dram_pkt->burstHelper;
739            dram_pkt->burstHelper = NULL;
740        }
741    } else {
742        // it is not a split packet
743        accessAndRespond(dram_pkt->pkt, frontendLatency + backendLatency);
744    }
745
746    delete respQueue.front();
747    respQueue.pop_front();
748
749    if (!respQueue.empty()) {
750        assert(respQueue.front()->readyTime >= curTick());
751        assert(!respondEvent.scheduled());
752        schedule(respondEvent, respQueue.front()->readyTime);
753    } else {
754        // if there is nothing left in any queue, signal a drain
755        if (drainState() == DrainState::Draining &&
756            !totalWriteQueueSize && !totalReadQueueSize && allRanksDrained()) {
757
758            DPRINTF(Drain, "DRAM controller done draining\n");
759            signalDrainDone();
760        }
761    }
762
763    // We have made a location in the queue available at this point,
764    // so if there is a read that was forced to wait, retry now
765    if (retryRdReq) {
766        retryRdReq = false;
767        port.sendRetryReq();
768    }
769}
770
771DRAMCtrl::DRAMPacketQueue::iterator
772DRAMCtrl::chooseNext(DRAMPacketQueue& queue, Tick extra_col_delay)
773{
774    // This method does the arbitration between requests.
775
776    DRAMCtrl::DRAMPacketQueue::iterator ret = queue.end();
777
778    if (!queue.empty()) {
779        if (queue.size() == 1) {
780            // available rank corresponds to state refresh idle
781            DRAMPacket* dram_pkt = *(queue.begin());
782            if (ranks[dram_pkt->rank]->inRefIdleState()) {
783                ret = queue.begin();
784                DPRINTF(DRAM, "Single request, going to a free rank\n");
785            } else {
786                DPRINTF(DRAM, "Single request, going to a busy rank\n");
787            }
788        } else if (memSchedPolicy == Enums::fcfs) {
789            // check if there is a packet going to a free rank
790            for (auto i = queue.begin(); i != queue.end(); ++i) {
791                DRAMPacket* dram_pkt = *i;
792                if (ranks[dram_pkt->rank]->inRefIdleState()) {
793                    ret = i;
794                    break;
795                }
796            }
797        } else if (memSchedPolicy == Enums::frfcfs) {
798            ret = chooseNextFRFCFS(queue, extra_col_delay);
799        } else {
800            panic("No scheduling policy chosen\n");
801        }
802    }
803    return ret;
804}
805
806DRAMCtrl::DRAMPacketQueue::iterator
807DRAMCtrl::chooseNextFRFCFS(DRAMPacketQueue& queue, Tick extra_col_delay)
808{
809    // Only determine this if needed
810    vector<uint32_t> earliest_banks(ranksPerChannel, 0);
811
812    // Has minBankPrep been called to populate earliest_banks?
813    bool filled_earliest_banks = false;
814    // can the PRE/ACT sequence be done without impacting utlization?
815    bool hidden_bank_prep = false;
816
817    // search for seamless row hits first, if no seamless row hit is
818    // found then determine if there are other packets that can be issued
819    // without incurring additional bus delay due to bank timing
820    // Will select closed rows first to enable more open row possibilies
821    // in future selections
822    bool found_hidden_bank = false;
823
824    // remember if we found a row hit, not seamless, but bank prepped
825    // and ready
826    bool found_prepped_pkt = false;
827
828    // if we have no row hit, prepped or not, and no seamless packet,
829    // just go for the earliest possible
830    bool found_earliest_pkt = false;
831
832    auto selected_pkt_it = queue.end();
833
834    // time we need to issue a column command to be seamless
835    const Tick min_col_at = std::max(nextBurstAt + extra_col_delay, curTick());
836
837    for (auto i = queue.begin(); i != queue.end() ; ++i) {
838        DRAMPacket* dram_pkt = *i;
839        const Bank& bank = dram_pkt->bankRef;
840        const Tick col_allowed_at = dram_pkt->isRead() ? bank.rdAllowedAt :
841                                                         bank.wrAllowedAt;
842
843        DPRINTF(DRAM, "%s checking packet in bank %d\n",
844                __func__, dram_pkt->bankRef.bank);
845
846        // check if rank is not doing a refresh and thus is available, if not,
847        // jump to the next packet
848        if (dram_pkt->rankRef.inRefIdleState()) {
849
850            DPRINTF(DRAM,
851                    "%s bank %d - Rank %d available\n", __func__,
852                    dram_pkt->bankRef.bank, dram_pkt->rankRef.rank);
853
854            // check if it is a row hit
855            if (bank.openRow == dram_pkt->row) {
856                // no additional rank-to-rank or same bank-group
857                // delays, or we switched read/write and might as well
858                // go for the row hit
859                if (col_allowed_at <= min_col_at) {
860                    // FCFS within the hits, giving priority to
861                    // commands that can issue seamlessly, without
862                    // additional delay, such as same rank accesses
863                    // and/or different bank-group accesses
864                    DPRINTF(DRAM, "%s Seamless row buffer hit\n", __func__);
865                    selected_pkt_it = i;
866                    // no need to look through the remaining queue entries
867                    break;
868                } else if (!found_hidden_bank && !found_prepped_pkt) {
869                    // if we did not find a packet to a closed row that can
870                    // issue the bank commands without incurring delay, and
871                    // did not yet find a packet to a prepped row, remember
872                    // the current one
873                    selected_pkt_it = i;
874                    found_prepped_pkt = true;
875                    DPRINTF(DRAM, "%s Prepped row buffer hit\n", __func__);
876                }
877            } else if (!found_earliest_pkt) {
878                // if we have not initialised the bank status, do it
879                // now, and only once per scheduling decisions
880                if (!filled_earliest_banks) {
881                    // determine entries with earliest bank delay
882                    std::tie(earliest_banks, hidden_bank_prep) =
883                        minBankPrep(queue, min_col_at);
884                    filled_earliest_banks = true;
885                }
886
887                // bank is amongst first available banks
888                // minBankPrep will give priority to packets that can
889                // issue seamlessly
890                if (bits(earliest_banks[dram_pkt->rank],
891                         dram_pkt->bank, dram_pkt->bank)) {
892                    found_earliest_pkt = true;
893                    found_hidden_bank = hidden_bank_prep;
894
895                    // give priority to packets that can issue
896                    // bank commands 'behind the scenes'
897                    // any additional delay if any will be due to
898                    // col-to-col command requirements
899                    if (hidden_bank_prep || !found_prepped_pkt)
900                        selected_pkt_it = i;
901                }
902            }
903        } else {
904            DPRINTF(DRAM, "%s bank %d - Rank %d not available\n", __func__,
905                    dram_pkt->bankRef.bank, dram_pkt->rankRef.rank);
906        }
907    }
908
909    if (selected_pkt_it == queue.end()) {
910        DPRINTF(DRAM, "%s no available ranks found\n", __func__);
911    }
912
913    return selected_pkt_it;
914}
915
916void
917DRAMCtrl::accessAndRespond(PacketPtr pkt, Tick static_latency)
918{
919    DPRINTF(DRAM, "Responding to Address %lld.. ",pkt->getAddr());
920
921    bool needsResponse = pkt->needsResponse();
922    // do the actual memory access which also turns the packet into a
923    // response
924    access(pkt);
925
926    // turn packet around to go back to requester if response expected
927    if (needsResponse) {
928        // access already turned the packet into a response
929        assert(pkt->isResponse());
930        // response_time consumes the static latency and is charged also
931        // with headerDelay that takes into account the delay provided by
932        // the xbar and also the payloadDelay that takes into account the
933        // number of data beats.
934        Tick response_time = curTick() + static_latency + pkt->headerDelay +
935                             pkt->payloadDelay;
936        // Here we reset the timing of the packet before sending it out.
937        pkt->headerDelay = pkt->payloadDelay = 0;
938
939        // queue the packet in the response queue to be sent out after
940        // the static latency has passed
941        port.schedTimingResp(pkt, response_time);
942    } else {
943        // @todo the packet is going to be deleted, and the DRAMPacket
944        // is still having a pointer to it
945        pendingDelete.reset(pkt);
946    }
947
948    DPRINTF(DRAM, "Done\n");
949
950    return;
951}
952
953void
954DRAMCtrl::activateBank(Rank& rank_ref, Bank& bank_ref,
955                       Tick act_tick, uint32_t row)
956{
957    assert(rank_ref.actTicks.size() == activationLimit);
958
959    DPRINTF(DRAM, "Activate at tick %d\n", act_tick);
960
961    // update the open row
962    assert(bank_ref.openRow == Bank::NO_ROW);
963    bank_ref.openRow = row;
964
965    // start counting anew, this covers both the case when we
966    // auto-precharged, and when this access is forced to
967    // precharge
968    bank_ref.bytesAccessed = 0;
969    bank_ref.rowAccesses = 0;
970
971    ++rank_ref.numBanksActive;
972    assert(rank_ref.numBanksActive <= banksPerRank);
973
974    DPRINTF(DRAM, "Activate bank %d, rank %d at tick %lld, now got %d active\n",
975            bank_ref.bank, rank_ref.rank, act_tick,
976            ranks[rank_ref.rank]->numBanksActive);
977
978    rank_ref.cmdList.push_back(Command(MemCommand::ACT, bank_ref.bank,
979                               act_tick));
980
981    DPRINTF(DRAMPower, "%llu,ACT,%d,%d\n", divCeil(act_tick, tCK) -
982            timeStampOffset, bank_ref.bank, rank_ref.rank);
983
984    // The next access has to respect tRAS for this bank
985    bank_ref.preAllowedAt = act_tick + tRAS;
986
987    // Respect the row-to-column command delay for both read and write cmds
988    bank_ref.rdAllowedAt = std::max(act_tick + tRCD, bank_ref.rdAllowedAt);
989    bank_ref.wrAllowedAt = std::max(act_tick + tRCD, bank_ref.wrAllowedAt);
990
991    // start by enforcing tRRD
992    for (int i = 0; i < banksPerRank; i++) {
993        // next activate to any bank in this rank must not happen
994        // before tRRD
995        if (bankGroupArch && (bank_ref.bankgr == rank_ref.banks[i].bankgr)) {
996            // bank group architecture requires longer delays between
997            // ACT commands within the same bank group.  Use tRRD_L
998            // in this case
999            rank_ref.banks[i].actAllowedAt = std::max(act_tick + tRRD_L,
1000                                             rank_ref.banks[i].actAllowedAt);
1001        } else {
1002            // use shorter tRRD value when either
1003            // 1) bank group architecture is not supportted
1004            // 2) bank is in a different bank group
1005            rank_ref.banks[i].actAllowedAt = std::max(act_tick + tRRD,
1006                                             rank_ref.banks[i].actAllowedAt);
1007        }
1008    }
1009
1010    // next, we deal with tXAW, if the activation limit is disabled
1011    // then we directly schedule an activate power event
1012    if (!rank_ref.actTicks.empty()) {
1013        // sanity check
1014        if (rank_ref.actTicks.back() &&
1015           (act_tick - rank_ref.actTicks.back()) < tXAW) {
1016            panic("Got %d activates in window %d (%llu - %llu) which "
1017                  "is smaller than %llu\n", activationLimit, act_tick -
1018                  rank_ref.actTicks.back(), act_tick,
1019                  rank_ref.actTicks.back(), tXAW);
1020        }
1021
1022        // shift the times used for the book keeping, the last element
1023        // (highest index) is the oldest one and hence the lowest value
1024        rank_ref.actTicks.pop_back();
1025
1026        // record an new activation (in the future)
1027        rank_ref.actTicks.push_front(act_tick);
1028
1029        // cannot activate more than X times in time window tXAW, push the
1030        // next one (the X + 1'st activate) to be tXAW away from the
1031        // oldest in our window of X
1032        if (rank_ref.actTicks.back() &&
1033           (act_tick - rank_ref.actTicks.back()) < tXAW) {
1034            DPRINTF(DRAM, "Enforcing tXAW with X = %d, next activate "
1035                    "no earlier than %llu\n", activationLimit,
1036                    rank_ref.actTicks.back() + tXAW);
1037            for (int j = 0; j < banksPerRank; j++)
1038                // next activate must not happen before end of window
1039                rank_ref.banks[j].actAllowedAt =
1040                    std::max(rank_ref.actTicks.back() + tXAW,
1041                             rank_ref.banks[j].actAllowedAt);
1042        }
1043    }
1044
1045    // at the point when this activate takes place, make sure we
1046    // transition to the active power state
1047    if (!rank_ref.activateEvent.scheduled())
1048        schedule(rank_ref.activateEvent, act_tick);
1049    else if (rank_ref.activateEvent.when() > act_tick)
1050        // move it sooner in time
1051        reschedule(rank_ref.activateEvent, act_tick);
1052}
1053
1054void
1055DRAMCtrl::prechargeBank(Rank& rank_ref, Bank& bank, Tick pre_at, bool trace)
1056{
1057    // make sure the bank has an open row
1058    assert(bank.openRow != Bank::NO_ROW);
1059
1060    // sample the bytes per activate here since we are closing
1061    // the page
1062    bytesPerActivate.sample(bank.bytesAccessed);
1063
1064    bank.openRow = Bank::NO_ROW;
1065
1066    // no precharge allowed before this one
1067    bank.preAllowedAt = pre_at;
1068
1069    Tick pre_done_at = pre_at + tRP;
1070
1071    bank.actAllowedAt = std::max(bank.actAllowedAt, pre_done_at);
1072
1073    assert(rank_ref.numBanksActive != 0);
1074    --rank_ref.numBanksActive;
1075
1076    DPRINTF(DRAM, "Precharging bank %d, rank %d at tick %lld, now got "
1077            "%d active\n", bank.bank, rank_ref.rank, pre_at,
1078            rank_ref.numBanksActive);
1079
1080    if (trace) {
1081
1082        rank_ref.cmdList.push_back(Command(MemCommand::PRE, bank.bank,
1083                                   pre_at));
1084        DPRINTF(DRAMPower, "%llu,PRE,%d,%d\n", divCeil(pre_at, tCK) -
1085                timeStampOffset, bank.bank, rank_ref.rank);
1086    }
1087    // if we look at the current number of active banks we might be
1088    // tempted to think the DRAM is now idle, however this can be
1089    // undone by an activate that is scheduled to happen before we
1090    // would have reached the idle state, so schedule an event and
1091    // rather check once we actually make it to the point in time when
1092    // the (last) precharge takes place
1093    if (!rank_ref.prechargeEvent.scheduled()) {
1094        schedule(rank_ref.prechargeEvent, pre_done_at);
1095        // New event, increment count
1096        ++rank_ref.outstandingEvents;
1097    } else if (rank_ref.prechargeEvent.when() < pre_done_at) {
1098        reschedule(rank_ref.prechargeEvent, pre_done_at);
1099    }
1100}
1101
1102void
1103DRAMCtrl::doDRAMAccess(DRAMPacket* dram_pkt)
1104{
1105    DPRINTF(DRAM, "Timing access to addr %lld, rank/bank/row %d %d %d\n",
1106            dram_pkt->addr, dram_pkt->rank, dram_pkt->bank, dram_pkt->row);
1107
1108    // get the rank
1109    Rank& rank = dram_pkt->rankRef;
1110
1111    // are we in or transitioning to a low-power state and have not scheduled
1112    // a power-up event?
1113    // if so, wake up from power down to issue RD/WR burst
1114    if (rank.inLowPowerState) {
1115        assert(rank.pwrState != PWR_SREF);
1116        rank.scheduleWakeUpEvent(tXP);
1117    }
1118
1119    // get the bank
1120    Bank& bank = dram_pkt->bankRef;
1121
1122    // for the state we need to track if it is a row hit or not
1123    bool row_hit = true;
1124
1125    // Determine the access latency and update the bank state
1126    if (bank.openRow == dram_pkt->row) {
1127        // nothing to do
1128    } else {
1129        row_hit = false;
1130
1131        // If there is a page open, precharge it.
1132        if (bank.openRow != Bank::NO_ROW) {
1133            prechargeBank(rank, bank, std::max(bank.preAllowedAt, curTick()));
1134        }
1135
1136        // next we need to account for the delay in activating the
1137        // page
1138        Tick act_tick = std::max(bank.actAllowedAt, curTick());
1139
1140        // Record the activation and deal with all the global timing
1141        // constraints caused be a new activation (tRRD and tXAW)
1142        activateBank(rank, bank, act_tick, dram_pkt->row);
1143    }
1144
1145    // respect any constraints on the command (e.g. tRCD or tCCD)
1146    const Tick col_allowed_at = dram_pkt->isRead() ?
1147                                          bank.rdAllowedAt : bank.wrAllowedAt;
1148
1149    // we need to wait until the bus is available before we can issue
1150    // the command; need minimum of tBURST between commands
1151    Tick cmd_at = std::max({col_allowed_at, nextBurstAt, curTick()});
1152
1153    // update the packet ready time
1154    dram_pkt->readyTime = cmd_at + tCL + tBURST;
1155
1156    // update the time for the next read/write burst for each
1157    // bank (add a max with tCCD/tCCD_L/tCCD_L_WR here)
1158    Tick dly_to_rd_cmd;
1159    Tick dly_to_wr_cmd;
1160    for (int j = 0; j < ranksPerChannel; j++) {
1161        for (int i = 0; i < banksPerRank; i++) {
1162            // next burst to same bank group in this rank must not happen
1163            // before tCCD_L.  Different bank group timing requirement is
1164            // tBURST; Add tCS for different ranks
1165            if (dram_pkt->rank == j) {
1166                if (bankGroupArch &&
1167                   (bank.bankgr == ranks[j]->banks[i].bankgr)) {
1168                    // bank group architecture requires longer delays between
1169                    // RD/WR burst commands to the same bank group.
1170                    // tCCD_L is default requirement for same BG timing
1171                    // tCCD_L_WR is required for write-to-write
1172                    // Need to also take bus turnaround delays into account
1173                    dly_to_rd_cmd = dram_pkt->isRead() ?
1174                                    tCCD_L : std::max(tCCD_L, wrToRdDly);
1175                    dly_to_wr_cmd = dram_pkt->isRead() ?
1176                                    std::max(tCCD_L, rdToWrDly) : tCCD_L_WR;
1177                } else {
1178                    // tBURST is default requirement for diff BG timing
1179                    // Need to also take bus turnaround delays into account
1180                    dly_to_rd_cmd = dram_pkt->isRead() ? tBURST : wrToRdDly;
1181                    dly_to_wr_cmd = dram_pkt->isRead() ? rdToWrDly : tBURST;
1182                }
1183            } else {
1184                // different rank is by default in a different bank group and
1185                // doesn't require longer tCCD or additional RTW, WTR delays
1186                // Need to account for rank-to-rank switching with tCS
1187                dly_to_wr_cmd = rankToRankDly;
1188                dly_to_rd_cmd = rankToRankDly;
1189            }
1190            ranks[j]->banks[i].rdAllowedAt = std::max(cmd_at + dly_to_rd_cmd,
1191                                             ranks[j]->banks[i].rdAllowedAt);
1192            ranks[j]->banks[i].wrAllowedAt = std::max(cmd_at + dly_to_wr_cmd,
1193                                             ranks[j]->banks[i].wrAllowedAt);
1194        }
1195    }
1196
1197    // Save rank of current access
1198    activeRank = dram_pkt->rank;
1199
1200    // If this is a write, we also need to respect the write recovery
1201    // time before a precharge, in the case of a read, respect the
1202    // read to precharge constraint
1203    bank.preAllowedAt = std::max(bank.preAllowedAt,
1204                                 dram_pkt->isRead() ? cmd_at + tRTP :
1205                                 dram_pkt->readyTime + tWR);
1206
1207    // increment the bytes accessed and the accesses per row
1208    bank.bytesAccessed += burstSize;
1209    ++bank.rowAccesses;
1210
1211    // if we reached the max, then issue with an auto-precharge
1212    bool auto_precharge = pageMgmt == Enums::close ||
1213        bank.rowAccesses == maxAccessesPerRow;
1214
1215    // if we did not hit the limit, we might still want to
1216    // auto-precharge
1217    if (!auto_precharge &&
1218        (pageMgmt == Enums::open_adaptive ||
1219         pageMgmt == Enums::close_adaptive)) {
1220        // a twist on the open and close page policies:
1221        // 1) open_adaptive page policy does not blindly keep the
1222        // page open, but close it if there are no row hits, and there
1223        // are bank conflicts in the queue
1224        // 2) close_adaptive page policy does not blindly close the
1225        // page, but closes it only if there are no row hits in the queue.
1226        // In this case, only force an auto precharge when there
1227        // are no same page hits in the queue
1228        bool got_more_hits = false;
1229        bool got_bank_conflict = false;
1230
1231        // either look at the read queue or write queue
1232        const std::vector<DRAMPacketQueue>& queue =
1233                dram_pkt->isRead() ? readQueue : writeQueue;
1234
1235        for (uint8_t i = 0; i < numPriorities(); ++i) {
1236            auto p = queue[i].begin();
1237            // keep on looking until we find a hit or reach the end of the queue
1238            // 1) if a hit is found, then both open and close adaptive policies keep
1239            // the page open
1240            // 2) if no hit is found, got_bank_conflict is set to true if a bank
1241            // conflict request is waiting in the queue
1242            // 3) make sure we are not considering the packet that we are
1243            // currently dealing with
1244            while (!got_more_hits && p != queue[i].end()) {
1245                if (dram_pkt != (*p)) {
1246                    bool same_rank_bank = (dram_pkt->rank == (*p)->rank) &&
1247                                          (dram_pkt->bank == (*p)->bank);
1248
1249                    bool same_row = dram_pkt->row == (*p)->row;
1250                    got_more_hits |= same_rank_bank && same_row;
1251                    got_bank_conflict |= same_rank_bank && !same_row;
1252                }
1253                ++p;
1254            }
1255
1256            if (got_more_hits)
1257                break;
1258        }
1259
1260        // auto pre-charge when either
1261        // 1) open_adaptive policy, we have not got any more hits, and
1262        //    have a bank conflict
1263        // 2) close_adaptive policy and we have not got any more hits
1264        auto_precharge = !got_more_hits &&
1265            (got_bank_conflict || pageMgmt == Enums::close_adaptive);
1266    }
1267
1268    // DRAMPower trace command to be written
1269    std::string mem_cmd = dram_pkt->isRead() ? "RD" : "WR";
1270
1271    // MemCommand required for DRAMPower library
1272    MemCommand::cmds command = (mem_cmd == "RD") ? MemCommand::RD :
1273                                                   MemCommand::WR;
1274
1275    // Update bus state to reflect when previous command was issued
1276    nextBurstAt = cmd_at + tBURST;
1277
1278    DPRINTF(DRAM, "Access to %lld, ready at %lld next burst at %lld.\n",
1279            dram_pkt->addr, dram_pkt->readyTime, nextBurstAt);
1280
1281    dram_pkt->rankRef.cmdList.push_back(Command(command, dram_pkt->bank,
1282                                        cmd_at));
1283
1284    DPRINTF(DRAMPower, "%llu,%s,%d,%d\n", divCeil(cmd_at, tCK) -
1285            timeStampOffset, mem_cmd, dram_pkt->bank, dram_pkt->rank);
1286
1287    // if this access should use auto-precharge, then we are
1288    // closing the row after the read/write burst
1289    if (auto_precharge) {
1290        // if auto-precharge push a PRE command at the correct tick to the
1291        // list used by DRAMPower library to calculate power
1292        prechargeBank(rank, bank, std::max(curTick(), bank.preAllowedAt));
1293
1294        DPRINTF(DRAM, "Auto-precharged bank: %d\n", dram_pkt->bankId);
1295    }
1296
1297    // Update the minimum timing between the requests, this is a
1298    // conservative estimate of when we have to schedule the next
1299    // request to not introduce any unecessary bubbles. In most cases
1300    // we will wake up sooner than we have to.
1301    nextReqTime = nextBurstAt - (tRP + tRCD);
1302
1303    // Update the stats and schedule the next request
1304    if (dram_pkt->isRead()) {
1305        ++readsThisTime;
1306        if (row_hit)
1307            readRowHits++;
1308        bytesReadDRAM += burstSize;
1309        perBankRdBursts[dram_pkt->bankId]++;
1310
1311        // Update latency stats
1312        totMemAccLat += dram_pkt->readyTime - dram_pkt->entryTime;
1313        masterReadTotalLat[dram_pkt->masterId()] +=
1314            dram_pkt->readyTime - dram_pkt->entryTime;
1315
1316        totBusLat += tBURST;
1317        totQLat += cmd_at - dram_pkt->entryTime;
1318        masterReadBytes[dram_pkt->masterId()] += dram_pkt->size;
1319    } else {
1320        ++writesThisTime;
1321        if (row_hit)
1322            writeRowHits++;
1323        bytesWritten += burstSize;
1324        perBankWrBursts[dram_pkt->bankId]++;
1325        masterWriteBytes[dram_pkt->masterId()] += dram_pkt->size;
1326        masterWriteTotalLat[dram_pkt->masterId()] +=
1327            dram_pkt->readyTime - dram_pkt->entryTime;
1328    }
1329}
1330
1331void
1332DRAMCtrl::processNextReqEvent()
1333{
1334    // transition is handled by QoS algorithm if enabled
1335    if (turnPolicy) {
1336        // select bus state - only done if QoS algorithms are in use
1337        busStateNext = selectNextBusState();
1338    }
1339
1340    // detect bus state change
1341    bool switched_cmd_type = (busState != busStateNext);
1342    // record stats
1343    recordTurnaroundStats();
1344
1345    DPRINTF(DRAM, "QoS Turnarounds selected state %s %s\n",
1346            (busState==MemCtrl::READ)?"READ":"WRITE",
1347            switched_cmd_type?"[turnaround triggered]":"");
1348
1349    if (switched_cmd_type) {
1350        if (busState == READ) {
1351            DPRINTF(DRAM,
1352                    "Switching to writes after %d reads with %d reads "
1353                    "waiting\n", readsThisTime, totalReadQueueSize);
1354            rdPerTurnAround.sample(readsThisTime);
1355            readsThisTime = 0;
1356        } else {
1357            DPRINTF(DRAM,
1358                    "Switching to reads after %d writes with %d writes "
1359                    "waiting\n", writesThisTime, totalWriteQueueSize);
1360            wrPerTurnAround.sample(writesThisTime);
1361            writesThisTime = 0;
1362        }
1363    }
1364
1365    // updates current state
1366    busState = busStateNext;
1367
1368    // check ranks for refresh/wakeup - uses busStateNext, so done after turnaround
1369    // decisions
1370    int busyRanks = 0;
1371    for (auto r : ranks) {
1372        if (!r->inRefIdleState()) {
1373            if (r->pwrState != PWR_SREF) {
1374                // rank is busy refreshing
1375                DPRINTF(DRAMState, "Rank %d is not available\n", r->rank);
1376                busyRanks++;
1377
1378                // let the rank know that if it was waiting to drain, it
1379                // is now done and ready to proceed
1380                r->checkDrainDone();
1381            }
1382
1383            // check if we were in self-refresh and haven't started
1384            // to transition out
1385            if ((r->pwrState == PWR_SREF) && r->inLowPowerState) {
1386                DPRINTF(DRAMState, "Rank %d is in self-refresh\n", r->rank);
1387                // if we have commands queued to this rank and we don't have
1388                // a minimum number of active commands enqueued,
1389                // exit self-refresh
1390                if (r->forceSelfRefreshExit()) {
1391                    DPRINTF(DRAMState, "rank %d was in self refresh and"
1392                           " should wake up\n", r->rank);
1393                    //wake up from self-refresh
1394                    r->scheduleWakeUpEvent(tXS);
1395                    // things are brought back into action once a refresh is
1396                    // performed after self-refresh
1397                    // continue with selection for other ranks
1398                }
1399            }
1400        }
1401    }
1402
1403    if (busyRanks == ranksPerChannel) {
1404        // if all ranks are refreshing wait for them to finish
1405        // and stall this state machine without taking any further
1406        // action, and do not schedule a new nextReqEvent
1407        return;
1408    }
1409
1410    // when we get here it is either a read or a write
1411    if (busState == READ) {
1412
1413        // track if we should switch or not
1414        bool switch_to_writes = false;
1415
1416        if (totalReadQueueSize == 0) {
1417            // In the case there is no read request to go next,
1418            // trigger writes if we have passed the low threshold (or
1419            // if we are draining)
1420            if (!(totalWriteQueueSize == 0) &&
1421                (drainState() == DrainState::Draining ||
1422                 totalWriteQueueSize > writeLowThreshold)) {
1423
1424                DPRINTF(DRAM, "Switching to writes due to read queue empty\n");
1425                switch_to_writes = true;
1426            } else {
1427                // check if we are drained
1428                // not done draining until in PWR_IDLE state
1429                // ensuring all banks are closed and
1430                // have exited low power states
1431                if (drainState() == DrainState::Draining &&
1432                    respQueue.empty() && allRanksDrained()) {
1433
1434                    DPRINTF(Drain, "DRAM controller done draining\n");
1435                    signalDrainDone();
1436                }
1437
1438                // nothing to do, not even any point in scheduling an
1439                // event for the next request
1440                return;
1441            }
1442        } else {
1443
1444            bool read_found = false;
1445            DRAMPacketQueue::iterator to_read;
1446            uint8_t prio = numPriorities();
1447
1448            for (auto queue = readQueue.rbegin();
1449                 queue != readQueue.rend(); ++queue) {
1450
1451                prio--;
1452
1453                DPRINTF(QOS,
1454                        "DRAM controller checking READ queue [%d] priority [%d elements]\n",
1455                        prio, queue->size());
1456
1457                // Figure out which read request goes next
1458                // If we are changing command type, incorporate the minimum
1459                // bus turnaround delay which will be tCS (different rank) case
1460                to_read = chooseNext((*queue), switched_cmd_type ? tCS : 0);
1461
1462                if (to_read != queue->end()) {
1463                    // candidate read found
1464                    read_found = true;
1465                    break;
1466                }
1467            }
1468
1469            // if no read to an available rank is found then return
1470            // at this point. There could be writes to the available ranks
1471            // which are above the required threshold. However, to
1472            // avoid adding more complexity to the code, return and wait
1473            // for a refresh event to kick things into action again.
1474            if (!read_found) {
1475                DPRINTF(DRAM, "No Reads Found - exiting\n");
1476                return;
1477            }
1478
1479            auto dram_pkt = *to_read;
1480
1481            assert(dram_pkt->rankRef.inRefIdleState());
1482
1483            doDRAMAccess(dram_pkt);
1484
1485            // Every respQueue which will generate an event, increment count
1486            ++dram_pkt->rankRef.outstandingEvents;
1487            // sanity check
1488            assert(dram_pkt->size <= burstSize);
1489            assert(dram_pkt->readyTime >= curTick());
1490
1491            // log the response
1492            logResponse(MemCtrl::READ, (*to_read)->masterId(),
1493                        dram_pkt->qosValue(), dram_pkt->getAddr(), 1,
1494                        dram_pkt->readyTime - dram_pkt->entryTime);
1495
1496
1497            // Insert into response queue. It will be sent back to the
1498            // requester at its readyTime
1499            if (respQueue.empty()) {
1500                assert(!respondEvent.scheduled());
1501                schedule(respondEvent, dram_pkt->readyTime);
1502            } else {
1503                assert(respQueue.back()->readyTime <= dram_pkt->readyTime);
1504                assert(respondEvent.scheduled());
1505            }
1506
1507            respQueue.push_back(dram_pkt);
1508
1509            // we have so many writes that we have to transition
1510            if (totalWriteQueueSize > writeHighThreshold) {
1511                switch_to_writes = true;
1512            }
1513
1514            // remove the request from the queue - the iterator is no longer valid .
1515            readQueue[dram_pkt->qosValue()].erase(to_read);
1516        }
1517
1518        // switching to writes, either because the read queue is empty
1519        // and the writes have passed the low threshold (or we are
1520        // draining), or because the writes hit the hight threshold
1521        if (switch_to_writes) {
1522            // transition to writing
1523            busStateNext = WRITE;
1524        }
1525    } else {
1526
1527        bool write_found = false;
1528        DRAMPacketQueue::iterator to_write;
1529        uint8_t prio = numPriorities();
1530
1531        for (auto queue = writeQueue.rbegin();
1532             queue != writeQueue.rend(); ++queue) {
1533
1534            prio--;
1535
1536            DPRINTF(QOS,
1537                    "DRAM controller checking WRITE queue [%d] priority [%d elements]\n",
1538                    prio, queue->size());
1539
1540            // If we are changing command type, incorporate the minimum
1541            // bus turnaround delay
1542            to_write = chooseNext((*queue),
1543                                  switched_cmd_type ? std::min(tRTW, tCS) : 0);
1544
1545            if (to_write != queue->end()) {
1546                write_found = true;
1547                break;
1548            }
1549        }
1550
1551        // if there are no writes to a rank that is available to service
1552        // requests (i.e. rank is in refresh idle state) are found then
1553        // return. There could be reads to the available ranks. However, to
1554        // avoid adding more complexity to the code, return at this point and
1555        // wait for a refresh event to kick things into action again.
1556        if (!write_found) {
1557            DPRINTF(DRAM, "No Writes Found - exiting\n");
1558            return;
1559        }
1560
1561        auto dram_pkt = *to_write;
1562
1563        assert(dram_pkt->rankRef.inRefIdleState());
1564        // sanity check
1565        assert(dram_pkt->size <= burstSize);
1566
1567        doDRAMAccess(dram_pkt);
1568
1569        // removed write from queue, decrement count
1570        --dram_pkt->rankRef.writeEntries;
1571
1572        // Schedule write done event to decrement event count
1573        // after the readyTime has been reached
1574        // Only schedule latest write event to minimize events
1575        // required; only need to ensure that final event scheduled covers
1576        // the time that writes are outstanding and bus is active
1577        // to holdoff power-down entry events
1578        if (!dram_pkt->rankRef.writeDoneEvent.scheduled()) {
1579            schedule(dram_pkt->rankRef.writeDoneEvent, dram_pkt->readyTime);
1580            // New event, increment count
1581            ++dram_pkt->rankRef.outstandingEvents;
1582
1583        } else if (dram_pkt->rankRef.writeDoneEvent.when() <
1584                   dram_pkt->readyTime) {
1585
1586            reschedule(dram_pkt->rankRef.writeDoneEvent, dram_pkt->readyTime);
1587        }
1588
1589        isInWriteQueue.erase(burstAlign(dram_pkt->addr));
1590
1591        // log the response
1592        logResponse(MemCtrl::WRITE, dram_pkt->masterId(),
1593                    dram_pkt->qosValue(), dram_pkt->getAddr(), 1,
1594                    dram_pkt->readyTime - dram_pkt->entryTime);
1595
1596
1597        // remove the request from the queue - the iterator is no longer valid
1598        writeQueue[dram_pkt->qosValue()].erase(to_write);
1599
1600        delete dram_pkt;
1601
1602        // If we emptied the write queue, or got sufficiently below the
1603        // threshold (using the minWritesPerSwitch as the hysteresis) and
1604        // are not draining, or we have reads waiting and have done enough
1605        // writes, then switch to reads.
1606        bool below_threshold =
1607            totalWriteQueueSize + minWritesPerSwitch < writeLowThreshold;
1608
1609        if (totalWriteQueueSize == 0 ||
1610            (below_threshold && drainState() != DrainState::Draining) ||
1611            (totalReadQueueSize && writesThisTime >= minWritesPerSwitch)) {
1612
1613            // turn the bus back around for reads again
1614            busStateNext = READ;
1615
1616            // note that the we switch back to reads also in the idle
1617            // case, which eventually will check for any draining and
1618            // also pause any further scheduling if there is really
1619            // nothing to do
1620        }
1621    }
1622    // It is possible that a refresh to another rank kicks things back into
1623    // action before reaching this point.
1624    if (!nextReqEvent.scheduled())
1625        schedule(nextReqEvent, std::max(nextReqTime, curTick()));
1626
1627    // If there is space available and we have writes waiting then let
1628    // them retry. This is done here to ensure that the retry does not
1629    // cause a nextReqEvent to be scheduled before we do so as part of
1630    // the next request processing
1631    if (retryWrReq && totalWriteQueueSize < writeBufferSize) {
1632        retryWrReq = false;
1633        port.sendRetryReq();
1634    }
1635}
1636
1637pair<vector<uint32_t>, bool>
1638DRAMCtrl::minBankPrep(const DRAMPacketQueue& queue,
1639                      Tick min_col_at) const
1640{
1641    Tick min_act_at = MaxTick;
1642    vector<uint32_t> bank_mask(ranksPerChannel, 0);
1643
1644    // latest Tick for which ACT can occur without incurring additoinal
1645    // delay on the data bus
1646    const Tick hidden_act_max = std::max(min_col_at - tRCD, curTick());
1647
1648    // Flag condition when burst can issue back-to-back with previous burst
1649    bool found_seamless_bank = false;
1650
1651    // Flag condition when bank can be opened without incurring additional
1652    // delay on the data bus
1653    bool hidden_bank_prep = false;
1654
1655    // determine if we have queued transactions targetting the
1656    // bank in question
1657    vector<bool> got_waiting(ranksPerChannel * banksPerRank, false);
1658    for (const auto& p : queue) {
1659        if (p->rankRef.inRefIdleState())
1660            got_waiting[p->bankId] = true;
1661    }
1662
1663    // Find command with optimal bank timing
1664    // Will prioritize commands that can issue seamlessly.
1665    for (int i = 0; i < ranksPerChannel; i++) {
1666        for (int j = 0; j < banksPerRank; j++) {
1667            uint16_t bank_id = i * banksPerRank + j;
1668
1669            // if we have waiting requests for the bank, and it is
1670            // amongst the first available, update the mask
1671            if (got_waiting[bank_id]) {
1672                // make sure this rank is not currently refreshing.
1673                assert(ranks[i]->inRefIdleState());
1674                // simplistic approximation of when the bank can issue
1675                // an activate, ignoring any rank-to-rank switching
1676                // cost in this calculation
1677                Tick act_at = ranks[i]->banks[j].openRow == Bank::NO_ROW ?
1678                    std::max(ranks[i]->banks[j].actAllowedAt, curTick()) :
1679                    std::max(ranks[i]->banks[j].preAllowedAt, curTick()) + tRP;
1680
1681                // When is the earliest the R/W burst can issue?
1682                const Tick col_allowed_at = (busState == READ) ?
1683                                              ranks[i]->banks[j].rdAllowedAt :
1684                                              ranks[i]->banks[j].wrAllowedAt;
1685                Tick col_at = std::max(col_allowed_at, act_at + tRCD);
1686
1687                // bank can issue burst back-to-back (seamlessly) with
1688                // previous burst
1689                bool new_seamless_bank = col_at <= min_col_at;
1690
1691                // if we found a new seamless bank or we have no
1692                // seamless banks, and got a bank with an earlier
1693                // activate time, it should be added to the bit mask
1694                if (new_seamless_bank ||
1695                    (!found_seamless_bank && act_at <= min_act_at)) {
1696                    // if we did not have a seamless bank before, and
1697                    // we do now, reset the bank mask, also reset it
1698                    // if we have not yet found a seamless bank and
1699                    // the activate time is smaller than what we have
1700                    // seen so far
1701                    if (!found_seamless_bank &&
1702                        (new_seamless_bank || act_at < min_act_at)) {
1703                        std::fill(bank_mask.begin(), bank_mask.end(), 0);
1704                    }
1705
1706                    found_seamless_bank |= new_seamless_bank;
1707
1708                    // ACT can occur 'behind the scenes'
1709                    hidden_bank_prep = act_at <= hidden_act_max;
1710
1711                    // set the bit corresponding to the available bank
1712                    replaceBits(bank_mask[i], j, j, 1);
1713                    min_act_at = act_at;
1714                }
1715            }
1716        }
1717    }
1718
1719    return make_pair(bank_mask, hidden_bank_prep);
1720}
1721
1722DRAMCtrl::Rank::Rank(DRAMCtrl& _memory, const DRAMCtrlParams* _p, int rank)
1723    : EventManager(&_memory), memory(_memory),
1724      pwrStateTrans(PWR_IDLE), pwrStatePostRefresh(PWR_IDLE),
1725      pwrStateTick(0), refreshDueAt(0), pwrState(PWR_IDLE),
1726      refreshState(REF_IDLE), inLowPowerState(false), rank(rank),
1727      readEntries(0), writeEntries(0), outstandingEvents(0),
1728      wakeUpAllowedAt(0), power(_p, false), banks(_p->banks_per_rank),
1729      numBanksActive(0), actTicks(_p->activation_limit, 0),
1730      writeDoneEvent([this]{ processWriteDoneEvent(); }, name()),
1731      activateEvent([this]{ processActivateEvent(); }, name()),
1732      prechargeEvent([this]{ processPrechargeEvent(); }, name()),
1733      refreshEvent([this]{ processRefreshEvent(); }, name()),
1734      powerEvent([this]{ processPowerEvent(); }, name()),
1735      wakeUpEvent([this]{ processWakeUpEvent(); }, name())
1736{
1737    for (int b = 0; b < _p->banks_per_rank; b++) {
1738        banks[b].bank = b;
1739        // GDDR addressing of banks to BG is linear.
1740        // Here we assume that all DRAM generations address bank groups as
1741        // follows:
1742        if (_p->bank_groups_per_rank > 0) {
1743            // Simply assign lower bits to bank group in order to
1744            // rotate across bank groups as banks are incremented
1745            // e.g. with 4 banks per bank group and 16 banks total:
1746            //    banks 0,4,8,12  are in bank group 0
1747            //    banks 1,5,9,13  are in bank group 1
1748            //    banks 2,6,10,14 are in bank group 2
1749            //    banks 3,7,11,15 are in bank group 3
1750            banks[b].bankgr = b % _p->bank_groups_per_rank;
1751        } else {
1752            // No bank groups; simply assign to bank number
1753            banks[b].bankgr = b;
1754        }
1755    }
1756}
1757
1758void
1759DRAMCtrl::Rank::startup(Tick ref_tick)
1760{
1761    assert(ref_tick > curTick());
1762
1763    pwrStateTick = curTick();
1764
1765    // kick off the refresh, and give ourselves enough time to
1766    // precharge
1767    schedule(refreshEvent, ref_tick);
1768}
1769
1770void
1771DRAMCtrl::Rank::suspend()
1772{
1773    deschedule(refreshEvent);
1774
1775    // Update the stats
1776    updatePowerStats();
1777
1778    // don't automatically transition back to LP state after next REF
1779    pwrStatePostRefresh = PWR_IDLE;
1780}
1781
1782bool
1783DRAMCtrl::Rank::isQueueEmpty() const
1784{
1785    // check commmands in Q based on current bus direction
1786    bool no_queued_cmds = ((memory.busStateNext == READ) && (readEntries == 0))
1787                          || ((memory.busStateNext == WRITE) &&
1788                              (writeEntries == 0));
1789    return no_queued_cmds;
1790}
1791
1792void
1793DRAMCtrl::Rank::checkDrainDone()
1794{
1795    // if this rank was waiting to drain it is now able to proceed to
1796    // precharge
1797    if (refreshState == REF_DRAIN) {
1798        DPRINTF(DRAM, "Refresh drain done, now precharging\n");
1799
1800        refreshState = REF_PD_EXIT;
1801
1802        // hand control back to the refresh event loop
1803        schedule(refreshEvent, curTick());
1804    }
1805}
1806
1807void
1808DRAMCtrl::Rank::flushCmdList()
1809{
1810    // at the moment sort the list of commands and update the counters
1811    // for DRAMPower libray when doing a refresh
1812    sort(cmdList.begin(), cmdList.end(), DRAMCtrl::sortTime);
1813
1814    auto next_iter = cmdList.begin();
1815    // push to commands to DRAMPower
1816    for ( ; next_iter != cmdList.end() ; ++next_iter) {
1817         Command cmd = *next_iter;
1818         if (cmd.timeStamp <= curTick()) {
1819             // Move all commands at or before curTick to DRAMPower
1820             power.powerlib.doCommand(cmd.type, cmd.bank,
1821                                      divCeil(cmd.timeStamp, memory.tCK) -
1822                                      memory.timeStampOffset);
1823         } else {
1824             // done - found all commands at or before curTick()
1825             // next_iter references the 1st command after curTick
1826             break;
1827         }
1828    }
1829    // reset cmdList to only contain commands after curTick
1830    // if there are no commands after curTick, updated cmdList will be empty
1831    // in this case, next_iter is cmdList.end()
1832    cmdList.assign(next_iter, cmdList.end());
1833}
1834
1835void
1836DRAMCtrl::Rank::processActivateEvent()
1837{
1838    // we should transition to the active state as soon as any bank is active
1839    if (pwrState != PWR_ACT)
1840        // note that at this point numBanksActive could be back at
1841        // zero again due to a precharge scheduled in the future
1842        schedulePowerEvent(PWR_ACT, curTick());
1843}
1844
1845void
1846DRAMCtrl::Rank::processPrechargeEvent()
1847{
1848    // counter should at least indicate one outstanding request
1849    // for this precharge
1850    assert(outstandingEvents > 0);
1851    // precharge complete, decrement count
1852    --outstandingEvents;
1853
1854    // if we reached zero, then special conditions apply as we track
1855    // if all banks are precharged for the power models
1856    if (numBanksActive == 0) {
1857        // no reads to this rank in the Q and no pending
1858        // RD/WR or refresh commands
1859        if (isQueueEmpty() && outstandingEvents == 0) {
1860            // should still be in ACT state since bank still open
1861            assert(pwrState == PWR_ACT);
1862
1863            // All banks closed - switch to precharge power down state.
1864            DPRINTF(DRAMState, "Rank %d sleep at tick %d\n",
1865                    rank, curTick());
1866            powerDownSleep(PWR_PRE_PDN, curTick());
1867        } else {
1868            // we should transition to the idle state when the last bank
1869            // is precharged
1870            schedulePowerEvent(PWR_IDLE, curTick());
1871        }
1872    }
1873}
1874
1875void
1876DRAMCtrl::Rank::processWriteDoneEvent()
1877{
1878    // counter should at least indicate one outstanding request
1879    // for this write
1880    assert(outstandingEvents > 0);
1881    // Write transfer on bus has completed
1882    // decrement per rank counter
1883    --outstandingEvents;
1884}
1885
1886void
1887DRAMCtrl::Rank::processRefreshEvent()
1888{
1889    // when first preparing the refresh, remember when it was due
1890    if ((refreshState == REF_IDLE) || (refreshState == REF_SREF_EXIT)) {
1891        // remember when the refresh is due
1892        refreshDueAt = curTick();
1893
1894        // proceed to drain
1895        refreshState = REF_DRAIN;
1896
1897        // make nonzero while refresh is pending to ensure
1898        // power down and self-refresh are not entered
1899        ++outstandingEvents;
1900
1901        DPRINTF(DRAM, "Refresh due\n");
1902    }
1903
1904    // let any scheduled read or write to the same rank go ahead,
1905    // after which it will
1906    // hand control back to this event loop
1907    if (refreshState == REF_DRAIN) {
1908        // if a request is at the moment being handled and this request is
1909        // accessing the current rank then wait for it to finish
1910        if ((rank == memory.activeRank)
1911            && (memory.nextReqEvent.scheduled())) {
1912            // hand control over to the request loop until it is
1913            // evaluated next
1914            DPRINTF(DRAM, "Refresh awaiting draining\n");
1915
1916            return;
1917        } else {
1918            refreshState = REF_PD_EXIT;
1919        }
1920    }
1921
1922    // at this point, ensure that rank is not in a power-down state
1923    if (refreshState == REF_PD_EXIT) {
1924        // if rank was sleeping and we have't started exit process,
1925        // wake-up for refresh
1926        if (inLowPowerState) {
1927            DPRINTF(DRAM, "Wake Up for refresh\n");
1928            // save state and return after refresh completes
1929            scheduleWakeUpEvent(memory.tXP);
1930            return;
1931        } else {
1932            refreshState = REF_PRE;
1933        }
1934    }
1935
1936    // at this point, ensure that all banks are precharged
1937    if (refreshState == REF_PRE) {
1938        // precharge any active bank
1939        if (numBanksActive != 0) {
1940            // at the moment, we use a precharge all even if there is
1941            // only a single bank open
1942            DPRINTF(DRAM, "Precharging all\n");
1943
1944            // first determine when we can precharge
1945            Tick pre_at = curTick();
1946
1947            for (auto &b : banks) {
1948                // respect both causality and any existing bank
1949                // constraints, some banks could already have a
1950                // (auto) precharge scheduled
1951                pre_at = std::max(b.preAllowedAt, pre_at);
1952            }
1953
1954            // make sure all banks per rank are precharged, and for those that
1955            // already are, update their availability
1956            Tick act_allowed_at = pre_at + memory.tRP;
1957
1958            for (auto &b : banks) {
1959                if (b.openRow != Bank::NO_ROW) {
1960                    memory.prechargeBank(*this, b, pre_at, false);
1961                } else {
1962                    b.actAllowedAt = std::max(b.actAllowedAt, act_allowed_at);
1963                    b.preAllowedAt = std::max(b.preAllowedAt, pre_at);
1964                }
1965            }
1966
1967            // precharge all banks in rank
1968            cmdList.push_back(Command(MemCommand::PREA, 0, pre_at));
1969
1970            DPRINTF(DRAMPower, "%llu,PREA,0,%d\n",
1971                    divCeil(pre_at, memory.tCK) -
1972                            memory.timeStampOffset, rank);
1973        } else if ((pwrState == PWR_IDLE) && (outstandingEvents == 1))  {
1974            // Banks are closed, have transitioned to IDLE state, and
1975            // no outstanding ACT,RD/WR,Auto-PRE sequence scheduled
1976            DPRINTF(DRAM, "All banks already precharged, starting refresh\n");
1977
1978            // go ahead and kick the power state machine into gear since
1979            // we are already idle
1980            schedulePowerEvent(PWR_REF, curTick());
1981        } else {
1982            // banks state is closed but haven't transitioned pwrState to IDLE
1983            // or have outstanding ACT,RD/WR,Auto-PRE sequence scheduled
1984            // should have outstanding precharge event in this case
1985            assert(prechargeEvent.scheduled());
1986            // will start refresh when pwrState transitions to IDLE
1987        }
1988
1989        assert(numBanksActive == 0);
1990
1991        // wait for all banks to be precharged, at which point the
1992        // power state machine will transition to the idle state, and
1993        // automatically move to a refresh, at that point it will also
1994        // call this method to get the refresh event loop going again
1995        return;
1996    }
1997
1998    // last but not least we perform the actual refresh
1999    if (refreshState == REF_START) {
2000        // should never get here with any banks active
2001        assert(numBanksActive == 0);
2002        assert(pwrState == PWR_REF);
2003
2004        Tick ref_done_at = curTick() + memory.tRFC;
2005
2006        for (auto &b : banks) {
2007            b.actAllowedAt = ref_done_at;
2008        }
2009
2010        // at the moment this affects all ranks
2011        cmdList.push_back(Command(MemCommand::REF, 0, curTick()));
2012
2013        // Update the stats
2014        updatePowerStats();
2015
2016        DPRINTF(DRAMPower, "%llu,REF,0,%d\n", divCeil(curTick(), memory.tCK) -
2017                memory.timeStampOffset, rank);
2018
2019        // Update for next refresh
2020        refreshDueAt += memory.tREFI;
2021
2022        // make sure we did not wait so long that we cannot make up
2023        // for it
2024        if (refreshDueAt < ref_done_at) {
2025            fatal("Refresh was delayed so long we cannot catch up\n");
2026        }
2027
2028        // Run the refresh and schedule event to transition power states
2029        // when refresh completes
2030        refreshState = REF_RUN;
2031        schedule(refreshEvent, ref_done_at);
2032        return;
2033    }
2034
2035    if (refreshState == REF_RUN) {
2036        // should never get here with any banks active
2037        assert(numBanksActive == 0);
2038        assert(pwrState == PWR_REF);
2039
2040        assert(!powerEvent.scheduled());
2041
2042        if ((memory.drainState() == DrainState::Draining) ||
2043            (memory.drainState() == DrainState::Drained)) {
2044            // if draining, do not re-enter low-power mode.
2045            // simply go to IDLE and wait
2046            schedulePowerEvent(PWR_IDLE, curTick());
2047        } else {
2048            // At the moment, we sleep when the refresh ends and wait to be
2049            // woken up again if previously in a low-power state.
2050            if (pwrStatePostRefresh != PWR_IDLE) {
2051                // power State should be power Refresh
2052                assert(pwrState == PWR_REF);
2053                DPRINTF(DRAMState, "Rank %d sleeping after refresh and was in "
2054                        "power state %d before refreshing\n", rank,
2055                        pwrStatePostRefresh);
2056                powerDownSleep(pwrState, curTick());
2057
2058            // Force PRE power-down if there are no outstanding commands
2059            // in Q after refresh.
2060            } else if (isQueueEmpty()) {
2061                // still have refresh event outstanding but there should
2062                // be no other events outstanding
2063                assert(outstandingEvents == 1);
2064                DPRINTF(DRAMState, "Rank %d sleeping after refresh but was NOT"
2065                        " in a low power state before refreshing\n", rank);
2066                powerDownSleep(PWR_PRE_PDN, curTick());
2067
2068            } else {
2069                // move to the idle power state once the refresh is done, this
2070                // will also move the refresh state machine to the refresh
2071                // idle state
2072                schedulePowerEvent(PWR_IDLE, curTick());
2073            }
2074        }
2075
2076        // At this point, we have completed the current refresh.
2077        // In the SREF bypass case, we do not get to this state in the
2078        // refresh STM and therefore can always schedule next event.
2079        // Compensate for the delay in actually performing the refresh
2080        // when scheduling the next one
2081        schedule(refreshEvent, refreshDueAt - memory.tRP);
2082
2083        DPRINTF(DRAMState, "Refresh done at %llu and next refresh"
2084                " at %llu\n", curTick(), refreshDueAt);
2085    }
2086}
2087
2088void
2089DRAMCtrl::Rank::schedulePowerEvent(PowerState pwr_state, Tick tick)
2090{
2091    // respect causality
2092    assert(tick >= curTick());
2093
2094    if (!powerEvent.scheduled()) {
2095        DPRINTF(DRAMState, "Scheduling power event at %llu to state %d\n",
2096                tick, pwr_state);
2097
2098        // insert the new transition
2099        pwrStateTrans = pwr_state;
2100
2101        schedule(powerEvent, tick);
2102    } else {
2103        panic("Scheduled power event at %llu to state %d, "
2104              "with scheduled event at %llu to %d\n", tick, pwr_state,
2105              powerEvent.when(), pwrStateTrans);
2106    }
2107}
2108
2109void
2110DRAMCtrl::Rank::powerDownSleep(PowerState pwr_state, Tick tick)
2111{
2112    // if low power state is active low, schedule to active low power state.
2113    // in reality tCKE is needed to enter active low power. This is neglected
2114    // here and could be added in the future.
2115    if (pwr_state == PWR_ACT_PDN) {
2116        schedulePowerEvent(pwr_state, tick);
2117        // push command to DRAMPower
2118        cmdList.push_back(Command(MemCommand::PDN_F_ACT, 0, tick));
2119        DPRINTF(DRAMPower, "%llu,PDN_F_ACT,0,%d\n", divCeil(tick,
2120                memory.tCK) - memory.timeStampOffset, rank);
2121    } else if (pwr_state == PWR_PRE_PDN) {
2122        // if low power state is precharge low, schedule to precharge low
2123        // power state. In reality tCKE is needed to enter active low power.
2124        // This is neglected here.
2125        schedulePowerEvent(pwr_state, tick);
2126        //push Command to DRAMPower
2127        cmdList.push_back(Command(MemCommand::PDN_F_PRE, 0, tick));
2128        DPRINTF(DRAMPower, "%llu,PDN_F_PRE,0,%d\n", divCeil(tick,
2129                memory.tCK) - memory.timeStampOffset, rank);
2130    } else if (pwr_state == PWR_REF) {
2131        // if a refresh just occurred
2132        // transition to PRE_PDN now that all banks are closed
2133        // precharge power down requires tCKE to enter. For simplicity
2134        // this is not considered.
2135        schedulePowerEvent(PWR_PRE_PDN, tick);
2136        //push Command to DRAMPower
2137        cmdList.push_back(Command(MemCommand::PDN_F_PRE, 0, tick));
2138        DPRINTF(DRAMPower, "%llu,PDN_F_PRE,0,%d\n", divCeil(tick,
2139                memory.tCK) - memory.timeStampOffset, rank);
2140    } else if (pwr_state == PWR_SREF) {
2141        // should only enter SREF after PRE-PD wakeup to do a refresh
2142        assert(pwrStatePostRefresh == PWR_PRE_PDN);
2143        // self refresh requires time tCKESR to enter. For simplicity,
2144        // this is not considered.
2145        schedulePowerEvent(PWR_SREF, tick);
2146        // push Command to DRAMPower
2147        cmdList.push_back(Command(MemCommand::SREN, 0, tick));
2148        DPRINTF(DRAMPower, "%llu,SREN,0,%d\n", divCeil(tick,
2149                memory.tCK) - memory.timeStampOffset, rank);
2150    }
2151    // Ensure that we don't power-down and back up in same tick
2152    // Once we commit to PD entry, do it and wait for at least 1tCK
2153    // This could be replaced with tCKE if/when that is added to the model
2154    wakeUpAllowedAt = tick + memory.tCK;
2155
2156    // Transitioning to a low power state, set flag
2157    inLowPowerState = true;
2158}
2159
2160void
2161DRAMCtrl::Rank::scheduleWakeUpEvent(Tick exit_delay)
2162{
2163    Tick wake_up_tick = std::max(curTick(), wakeUpAllowedAt);
2164
2165    DPRINTF(DRAMState, "Scheduling wake-up for rank %d at tick %d\n",
2166            rank, wake_up_tick);
2167
2168    // if waking for refresh, hold previous state
2169    // else reset state back to IDLE
2170    if (refreshState == REF_PD_EXIT) {
2171        pwrStatePostRefresh = pwrState;
2172    } else {
2173        // don't automatically transition back to LP state after next REF
2174        pwrStatePostRefresh = PWR_IDLE;
2175    }
2176
2177    // schedule wake-up with event to ensure entry has completed before
2178    // we try to wake-up
2179    schedule(wakeUpEvent, wake_up_tick);
2180
2181    for (auto &b : banks) {
2182        // respect both causality and any existing bank
2183        // constraints, some banks could already have a
2184        // (auto) precharge scheduled
2185        b.wrAllowedAt = std::max(wake_up_tick + exit_delay, b.wrAllowedAt);
2186        b.rdAllowedAt = std::max(wake_up_tick + exit_delay, b.rdAllowedAt);
2187        b.preAllowedAt = std::max(wake_up_tick + exit_delay, b.preAllowedAt);
2188        b.actAllowedAt = std::max(wake_up_tick + exit_delay, b.actAllowedAt);
2189    }
2190    // Transitioning out of low power state, clear flag
2191    inLowPowerState = false;
2192
2193    // push to DRAMPower
2194    // use pwrStateTrans for cases where we have a power event scheduled
2195    // to enter low power that has not yet been processed
2196    if (pwrStateTrans == PWR_ACT_PDN) {
2197        cmdList.push_back(Command(MemCommand::PUP_ACT, 0, wake_up_tick));
2198        DPRINTF(DRAMPower, "%llu,PUP_ACT,0,%d\n", divCeil(wake_up_tick,
2199                memory.tCK) - memory.timeStampOffset, rank);
2200
2201    } else if (pwrStateTrans == PWR_PRE_PDN) {
2202        cmdList.push_back(Command(MemCommand::PUP_PRE, 0, wake_up_tick));
2203        DPRINTF(DRAMPower, "%llu,PUP_PRE,0,%d\n", divCeil(wake_up_tick,
2204                memory.tCK) - memory.timeStampOffset, rank);
2205    } else if (pwrStateTrans == PWR_SREF) {
2206        cmdList.push_back(Command(MemCommand::SREX, 0, wake_up_tick));
2207        DPRINTF(DRAMPower, "%llu,SREX,0,%d\n", divCeil(wake_up_tick,
2208                memory.tCK) - memory.timeStampOffset, rank);
2209    }
2210}
2211
2212void
2213DRAMCtrl::Rank::processWakeUpEvent()
2214{
2215    // Should be in a power-down or self-refresh state
2216    assert((pwrState == PWR_ACT_PDN) || (pwrState == PWR_PRE_PDN) ||
2217           (pwrState == PWR_SREF));
2218
2219    // Check current state to determine transition state
2220    if (pwrState == PWR_ACT_PDN) {
2221        // banks still open, transition to PWR_ACT
2222        schedulePowerEvent(PWR_ACT, curTick());
2223    } else {
2224        // transitioning from a precharge power-down or self-refresh state
2225        // banks are closed - transition to PWR_IDLE
2226        schedulePowerEvent(PWR_IDLE, curTick());
2227    }
2228}
2229
2230void
2231DRAMCtrl::Rank::processPowerEvent()
2232{
2233    assert(curTick() >= pwrStateTick);
2234    // remember where we were, and for how long
2235    Tick duration = curTick() - pwrStateTick;
2236    PowerState prev_state = pwrState;
2237
2238    // update the accounting
2239    pwrStateTime[prev_state] += duration;
2240
2241    // track to total idle time
2242    if ((prev_state == PWR_PRE_PDN) || (prev_state == PWR_ACT_PDN) ||
2243        (prev_state == PWR_SREF)) {
2244        totalIdleTime += duration;
2245    }
2246
2247    pwrState = pwrStateTrans;
2248    pwrStateTick = curTick();
2249
2250    // if rank was refreshing, make sure to start scheduling requests again
2251    if (prev_state == PWR_REF) {
2252        // bus IDLED prior to REF
2253        // counter should be one for refresh command only
2254        assert(outstandingEvents == 1);
2255        // REF complete, decrement count and go back to IDLE
2256        --outstandingEvents;
2257        refreshState = REF_IDLE;
2258
2259        DPRINTF(DRAMState, "Was refreshing for %llu ticks\n", duration);
2260        // if moving back to power-down after refresh
2261        if (pwrState != PWR_IDLE) {
2262            assert(pwrState == PWR_PRE_PDN);
2263            DPRINTF(DRAMState, "Switching to power down state after refreshing"
2264                    " rank %d at %llu tick\n", rank, curTick());
2265        }
2266
2267        // completed refresh event, ensure next request is scheduled
2268        if (!memory.nextReqEvent.scheduled()) {
2269            DPRINTF(DRAM, "Scheduling next request after refreshing"
2270                           " rank %d\n", rank);
2271            schedule(memory.nextReqEvent, curTick());
2272        }
2273    }
2274
2275    if ((pwrState == PWR_ACT) && (refreshState == REF_PD_EXIT)) {
2276        // have exited ACT PD
2277        assert(prev_state == PWR_ACT_PDN);
2278
2279        // go back to REF event and close banks
2280        refreshState = REF_PRE;
2281        schedule(refreshEvent, curTick());
2282    } else if (pwrState == PWR_IDLE) {
2283        DPRINTF(DRAMState, "All banks precharged\n");
2284        if (prev_state == PWR_SREF) {
2285            // set refresh state to REF_SREF_EXIT, ensuring inRefIdleState
2286            // continues to return false during tXS after SREF exit
2287            // Schedule a refresh which kicks things back into action
2288            // when it finishes
2289            refreshState = REF_SREF_EXIT;
2290            schedule(refreshEvent, curTick() + memory.tXS);
2291        } else {
2292            // if we have a pending refresh, and are now moving to
2293            // the idle state, directly transition to, or schedule refresh
2294            if ((refreshState == REF_PRE) || (refreshState == REF_PD_EXIT)) {
2295                // ensure refresh is restarted only after final PRE command.
2296                // do not restart refresh if controller is in an intermediate
2297                // state, after PRE_PDN exit, when banks are IDLE but an
2298                // ACT is scheduled.
2299                if (!activateEvent.scheduled()) {
2300                    // there should be nothing waiting at this point
2301                    assert(!powerEvent.scheduled());
2302                    if (refreshState == REF_PD_EXIT) {
2303                        // exiting PRE PD, will be in IDLE until tXP expires
2304                        // and then should transition to PWR_REF state
2305                        assert(prev_state == PWR_PRE_PDN);
2306                        schedulePowerEvent(PWR_REF, curTick() + memory.tXP);
2307                    } else if (refreshState == REF_PRE) {
2308                        // can directly move to PWR_REF state and proceed below
2309                        pwrState = PWR_REF;
2310                    }
2311                } else {
2312                    // must have PRE scheduled to transition back to IDLE
2313                    // and re-kick off refresh
2314                    assert(prechargeEvent.scheduled());
2315                }
2316            }
2317        }
2318    }
2319
2320    // transition to the refresh state and re-start refresh process
2321    // refresh state machine will schedule the next power state transition
2322    if (pwrState == PWR_REF) {
2323        // completed final PRE for refresh or exiting power-down
2324        assert(refreshState == REF_PRE || refreshState == REF_PD_EXIT);
2325
2326        // exited PRE PD for refresh, with no pending commands
2327        // bypass auto-refresh and go straight to SREF, where memory
2328        // will issue refresh immediately upon entry
2329        if (pwrStatePostRefresh == PWR_PRE_PDN && isQueueEmpty() &&
2330           (memory.drainState() != DrainState::Draining) &&
2331           (memory.drainState() != DrainState::Drained)) {
2332            DPRINTF(DRAMState, "Rank %d bypassing refresh and transitioning "
2333                    "to self refresh at %11u tick\n", rank, curTick());
2334            powerDownSleep(PWR_SREF, curTick());
2335
2336            // Since refresh was bypassed, remove event by decrementing count
2337            assert(outstandingEvents == 1);
2338            --outstandingEvents;
2339
2340            // reset state back to IDLE temporarily until SREF is entered
2341            pwrState = PWR_IDLE;
2342
2343        // Not bypassing refresh for SREF entry
2344        } else {
2345            DPRINTF(DRAMState, "Refreshing\n");
2346
2347            // there should be nothing waiting at this point
2348            assert(!powerEvent.scheduled());
2349
2350            // kick the refresh event loop into action again, and that
2351            // in turn will schedule a transition to the idle power
2352            // state once the refresh is done
2353            schedule(refreshEvent, curTick());
2354
2355            // Banks transitioned to IDLE, start REF
2356            refreshState = REF_START;
2357        }
2358    }
2359
2360}
2361
2362void
2363DRAMCtrl::Rank::updatePowerStats()
2364{
2365    // All commands up to refresh have completed
2366    // flush cmdList to DRAMPower
2367    flushCmdList();
2368
2369    // Call the function that calculates window energy at intermediate update
2370    // events like at refresh, stats dump as well as at simulation exit.
2371    // Window starts at the last time the calcWindowEnergy function was called
2372    // and is upto current time.
2373    power.powerlib.calcWindowEnergy(divCeil(curTick(), memory.tCK) -
2374                                    memory.timeStampOffset);
2375
2376    // Get the energy from DRAMPower
2377    Data::MemoryPowerModel::Energy energy = power.powerlib.getEnergy();
2378
2379    // The energy components inside the power lib are calculated over
2380    // the window so accumulate into the corresponding gem5 stat
2381    actEnergy += energy.act_energy * memory.devicesPerRank;
2382    preEnergy += energy.pre_energy * memory.devicesPerRank;
2383    readEnergy += energy.read_energy * memory.devicesPerRank;
2384    writeEnergy += energy.write_energy * memory.devicesPerRank;
2385    refreshEnergy += energy.ref_energy * memory.devicesPerRank;
2386    actBackEnergy += energy.act_stdby_energy * memory.devicesPerRank;
2387    preBackEnergy += energy.pre_stdby_energy * memory.devicesPerRank;
2388    actPowerDownEnergy += energy.f_act_pd_energy * memory.devicesPerRank;
2389    prePowerDownEnergy += energy.f_pre_pd_energy * memory.devicesPerRank;
2390    selfRefreshEnergy += energy.sref_energy * memory.devicesPerRank;
2391
2392    // Accumulate window energy into the total energy.
2393    totalEnergy += energy.window_energy * memory.devicesPerRank;
2394    // Average power must not be accumulated but calculated over the time
2395    // since last stats reset. SimClock::Frequency is tick period not tick
2396    // frequency.
2397    //              energy (pJ)     1e-9
2398    // power (mW) = ----------- * ----------
2399    //              time (tick)   tick_frequency
2400    averagePower = (totalEnergy.value() /
2401                    (curTick() - memory.lastStatsResetTick)) *
2402                    (SimClock::Frequency / 1000000000.0);
2403}
2404
2405void
2406DRAMCtrl::Rank::computeStats()
2407{
2408    DPRINTF(DRAM,"Computing stats due to a dump callback\n");
2409
2410    // Update the stats
2411    updatePowerStats();
2412
2413    // final update of power state times
2414    pwrStateTime[pwrState] += (curTick() - pwrStateTick);
2415    pwrStateTick = curTick();
2416
2417}
2418
2419void
2420DRAMCtrl::Rank::resetStats() {
2421    // The only way to clear the counters in DRAMPower is to call
2422    // calcWindowEnergy function as that then calls clearCounters. The
2423    // clearCounters method itself is private.
2424    power.powerlib.calcWindowEnergy(divCeil(curTick(), memory.tCK) -
2425                                    memory.timeStampOffset);
2426
2427}
2428
2429void
2430DRAMCtrl::Rank::regStats()
2431{
2432    pwrStateTime
2433        .init(6)
2434        .name(name() + ".memoryStateTime")
2435        .desc("Time in different power states");
2436    pwrStateTime.subname(0, "IDLE");
2437    pwrStateTime.subname(1, "REF");
2438    pwrStateTime.subname(2, "SREF");
2439    pwrStateTime.subname(3, "PRE_PDN");
2440    pwrStateTime.subname(4, "ACT");
2441    pwrStateTime.subname(5, "ACT_PDN");
2442
2443    actEnergy
2444        .name(name() + ".actEnergy")
2445        .desc("Energy for activate commands per rank (pJ)");
2446
2447    preEnergy
2448        .name(name() + ".preEnergy")
2449        .desc("Energy for precharge commands per rank (pJ)");
2450
2451    readEnergy
2452        .name(name() + ".readEnergy")
2453        .desc("Energy for read commands per rank (pJ)");
2454
2455    writeEnergy
2456        .name(name() + ".writeEnergy")
2457        .desc("Energy for write commands per rank (pJ)");
2458
2459    refreshEnergy
2460        .name(name() + ".refreshEnergy")
2461        .desc("Energy for refresh commands per rank (pJ)");
2462
2463    actBackEnergy
2464        .name(name() + ".actBackEnergy")
2465        .desc("Energy for active background per rank (pJ)");
2466
2467    preBackEnergy
2468        .name(name() + ".preBackEnergy")
2469        .desc("Energy for precharge background per rank (pJ)");
2470
2471    actPowerDownEnergy
2472        .name(name() + ".actPowerDownEnergy")
2473        .desc("Energy for active power-down per rank (pJ)");
2474
2475    prePowerDownEnergy
2476        .name(name() + ".prePowerDownEnergy")
2477        .desc("Energy for precharge power-down per rank (pJ)");
2478
2479    selfRefreshEnergy
2480        .name(name() + ".selfRefreshEnergy")
2481        .desc("Energy for self refresh per rank (pJ)");
2482
2483    totalEnergy
2484        .name(name() + ".totalEnergy")
2485        .desc("Total energy per rank (pJ)");
2486
2487    averagePower
2488        .name(name() + ".averagePower")
2489        .desc("Core power per rank (mW)");
2490
2491    totalIdleTime
2492        .name(name() + ".totalIdleTime")
2493        .desc("Total Idle time Per DRAM Rank");
2494
2495    Stats::registerDumpCallback(new RankDumpCallback(this));
2496    Stats::registerResetCallback(new RankResetCallback(this));
2497}
2498void
2499DRAMCtrl::regStats()
2500{
2501    using namespace Stats;
2502
2503    MemCtrl::regStats();
2504
2505    for (auto r : ranks) {
2506        r->regStats();
2507    }
2508
2509    registerResetCallback(new MemResetCallback(this));
2510
2511    readReqs
2512        .name(name() + ".readReqs")
2513        .desc("Number of read requests accepted");
2514
2515    writeReqs
2516        .name(name() + ".writeReqs")
2517        .desc("Number of write requests accepted");
2518
2519    readBursts
2520        .name(name() + ".readBursts")
2521        .desc("Number of DRAM read bursts, "
2522              "including those serviced by the write queue");
2523
2524    writeBursts
2525        .name(name() + ".writeBursts")
2526        .desc("Number of DRAM write bursts, "
2527              "including those merged in the write queue");
2528
2529    servicedByWrQ
2530        .name(name() + ".servicedByWrQ")
2531        .desc("Number of DRAM read bursts serviced by the write queue");
2532
2533    mergedWrBursts
2534        .name(name() + ".mergedWrBursts")
2535        .desc("Number of DRAM write bursts merged with an existing one");
2536
2537    neitherReadNorWrite
2538        .name(name() + ".neitherReadNorWriteReqs")
2539        .desc("Number of requests that are neither read nor write");
2540
2541    perBankRdBursts
2542        .init(banksPerRank * ranksPerChannel)
2543        .name(name() + ".perBankRdBursts")
2544        .desc("Per bank write bursts");
2545
2546    perBankWrBursts
2547        .init(banksPerRank * ranksPerChannel)
2548        .name(name() + ".perBankWrBursts")
2549        .desc("Per bank write bursts");
2550
2551    avgRdQLen
2552        .name(name() + ".avgRdQLen")
2553        .desc("Average read queue length when enqueuing")
2554        .precision(2);
2555
2556    avgWrQLen
2557        .name(name() + ".avgWrQLen")
2558        .desc("Average write queue length when enqueuing")
2559        .precision(2);
2560
2561    totQLat
2562        .name(name() + ".totQLat")
2563        .desc("Total ticks spent queuing");
2564
2565    totBusLat
2566        .name(name() + ".totBusLat")
2567        .desc("Total ticks spent in databus transfers");
2568
2569    totMemAccLat
2570        .name(name() + ".totMemAccLat")
2571        .desc("Total ticks spent from burst creation until serviced "
2572              "by the DRAM");
2573
2574    avgQLat
2575        .name(name() + ".avgQLat")
2576        .desc("Average queueing delay per DRAM burst")
2577        .precision(2);
2578
2579    avgQLat = totQLat / (readBursts - servicedByWrQ);
2580
2581    avgBusLat
2582        .name(name() + ".avgBusLat")
2583        .desc("Average bus latency per DRAM burst")
2584        .precision(2);
2585
2586    avgBusLat = totBusLat / (readBursts - servicedByWrQ);
2587
2588    avgMemAccLat
2589        .name(name() + ".avgMemAccLat")
2590        .desc("Average memory access latency per DRAM burst")
2591        .precision(2);
2592
2593    avgMemAccLat = totMemAccLat / (readBursts - servicedByWrQ);
2594
2595    numRdRetry
2596        .name(name() + ".numRdRetry")
2597        .desc("Number of times read queue was full causing retry");
2598
2599    numWrRetry
2600        .name(name() + ".numWrRetry")
2601        .desc("Number of times write queue was full causing retry");
2602
2603    readRowHits
2604        .name(name() + ".readRowHits")
2605        .desc("Number of row buffer hits during reads");
2606
2607    writeRowHits
2608        .name(name() + ".writeRowHits")
2609        .desc("Number of row buffer hits during writes");
2610
2611    readRowHitRate
2612        .name(name() + ".readRowHitRate")
2613        .desc("Row buffer hit rate for reads")
2614        .precision(2);
2615
2616    readRowHitRate = (readRowHits / (readBursts - servicedByWrQ)) * 100;
2617
2618    writeRowHitRate
2619        .name(name() + ".writeRowHitRate")
2620        .desc("Row buffer hit rate for writes")
2621        .precision(2);
2622
2623    writeRowHitRate = (writeRowHits / (writeBursts - mergedWrBursts)) * 100;
2624
2625    readPktSize
2626        .init(ceilLog2(burstSize) + 1)
2627        .name(name() + ".readPktSize")
2628        .desc("Read request sizes (log2)");
2629
2630     writePktSize
2631        .init(ceilLog2(burstSize) + 1)
2632        .name(name() + ".writePktSize")
2633        .desc("Write request sizes (log2)");
2634
2635     rdQLenPdf
2636        .init(readBufferSize)
2637        .name(name() + ".rdQLenPdf")
2638        .desc("What read queue length does an incoming req see");
2639
2640     wrQLenPdf
2641        .init(writeBufferSize)
2642        .name(name() + ".wrQLenPdf")
2643        .desc("What write queue length does an incoming req see");
2644
2645     bytesPerActivate
2646         .init(maxAccessesPerRow ? maxAccessesPerRow : rowBufferSize)
2647         .name(name() + ".bytesPerActivate")
2648         .desc("Bytes accessed per row activation")
2649         .flags(nozero);
2650
2651     rdPerTurnAround
2652         .init(readBufferSize)
2653         .name(name() + ".rdPerTurnAround")
2654         .desc("Reads before turning the bus around for writes")
2655         .flags(nozero);
2656
2657     wrPerTurnAround
2658         .init(writeBufferSize)
2659         .name(name() + ".wrPerTurnAround")
2660         .desc("Writes before turning the bus around for reads")
2661         .flags(nozero);
2662
2663    bytesReadDRAM
2664        .name(name() + ".bytesReadDRAM")
2665        .desc("Total number of bytes read from DRAM");
2666
2667    bytesReadWrQ
2668        .name(name() + ".bytesReadWrQ")
2669        .desc("Total number of bytes read from write queue");
2670
2671    bytesWritten
2672        .name(name() + ".bytesWritten")
2673        .desc("Total number of bytes written to DRAM");
2674
2675    bytesReadSys
2676        .name(name() + ".bytesReadSys")
2677        .desc("Total read bytes from the system interface side");
2678
2679    bytesWrittenSys
2680        .name(name() + ".bytesWrittenSys")
2681        .desc("Total written bytes from the system interface side");
2682
2683    avgRdBW
2684        .name(name() + ".avgRdBW")
2685        .desc("Average DRAM read bandwidth in MiByte/s")
2686        .precision(2);
2687
2688    avgRdBW = (bytesReadDRAM / 1000000) / simSeconds;
2689
2690    avgWrBW
2691        .name(name() + ".avgWrBW")
2692        .desc("Average achieved write bandwidth in MiByte/s")
2693        .precision(2);
2694
2695    avgWrBW = (bytesWritten / 1000000) / simSeconds;
2696
2697    avgRdBWSys
2698        .name(name() + ".avgRdBWSys")
2699        .desc("Average system read bandwidth in MiByte/s")
2700        .precision(2);
2701
2702    avgRdBWSys = (bytesReadSys / 1000000) / simSeconds;
2703
2704    avgWrBWSys
2705        .name(name() + ".avgWrBWSys")
2706        .desc("Average system write bandwidth in MiByte/s")
2707        .precision(2);
2708
2709    avgWrBWSys = (bytesWrittenSys / 1000000) / simSeconds;
2710
2711    peakBW
2712        .name(name() + ".peakBW")
2713        .desc("Theoretical peak bandwidth in MiByte/s")
2714        .precision(2);
2715
2716    peakBW = (SimClock::Frequency / tBURST) * burstSize / 1000000;
2717
2718    busUtil
2719        .name(name() + ".busUtil")
2720        .desc("Data bus utilization in percentage")
2721        .precision(2);
2722    busUtil = (avgRdBW + avgWrBW) / peakBW * 100;
2723
2724    totGap
2725        .name(name() + ".totGap")
2726        .desc("Total gap between requests");
2727
2728    avgGap
2729        .name(name() + ".avgGap")
2730        .desc("Average gap between requests")
2731        .precision(2);
2732
2733    avgGap = totGap / (readReqs + writeReqs);
2734
2735    // Stats for DRAM Power calculation based on Micron datasheet
2736    busUtilRead
2737        .name(name() + ".busUtilRead")
2738        .desc("Data bus utilization in percentage for reads")
2739        .precision(2);
2740
2741    busUtilRead = avgRdBW / peakBW * 100;
2742
2743    busUtilWrite
2744        .name(name() + ".busUtilWrite")
2745        .desc("Data bus utilization in percentage for writes")
2746        .precision(2);
2747
2748    busUtilWrite = avgWrBW / peakBW * 100;
2749
2750    pageHitRate
2751        .name(name() + ".pageHitRate")
2752        .desc("Row buffer hit rate, read and write combined")
2753        .precision(2);
2754
2755    pageHitRate = (writeRowHits + readRowHits) /
2756        (writeBursts - mergedWrBursts + readBursts - servicedByWrQ) * 100;
2757
2758    // per-master bytes read and written to memory
2759    masterReadBytes
2760        .init(_system->maxMasters())
2761        .name(name() + ".masterReadBytes")
2762        .desc("Per-master bytes read from memory")
2763        .flags(nozero | nonan);
2764
2765    masterWriteBytes
2766        .init(_system->maxMasters())
2767        .name(name() + ".masterWriteBytes")
2768        .desc("Per-master bytes write to memory")
2769        .flags(nozero | nonan);
2770
2771    // per-master bytes read and written to memory rate
2772    masterReadRate.name(name() + ".masterReadRate")
2773        .desc("Per-master bytes read from memory rate (Bytes/sec)")
2774        .flags(nozero | nonan)
2775        .precision(12);
2776
2777    masterReadRate = masterReadBytes/simSeconds;
2778
2779    masterWriteRate
2780        .name(name() + ".masterWriteRate")
2781        .desc("Per-master bytes write to memory rate (Bytes/sec)")
2782        .flags(nozero | nonan)
2783        .precision(12);
2784
2785    masterWriteRate = masterWriteBytes/simSeconds;
2786
2787    masterReadAccesses
2788        .init(_system->maxMasters())
2789        .name(name() + ".masterReadAccesses")
2790        .desc("Per-master read serviced memory accesses")
2791        .flags(nozero);
2792
2793    masterWriteAccesses
2794        .init(_system->maxMasters())
2795        .name(name() + ".masterWriteAccesses")
2796        .desc("Per-master write serviced memory accesses")
2797        .flags(nozero);
2798
2799
2800    masterReadTotalLat
2801        .init(_system->maxMasters())
2802        .name(name() + ".masterReadTotalLat")
2803        .desc("Per-master read total memory access latency")
2804        .flags(nozero | nonan);
2805
2806    masterReadAvgLat.name(name() + ".masterReadAvgLat")
2807        .desc("Per-master read average memory access latency")
2808        .flags(nonan)
2809        .precision(2);
2810
2811    masterReadAvgLat = masterReadTotalLat/masterReadAccesses;
2812
2813    masterWriteTotalLat
2814        .init(_system->maxMasters())
2815        .name(name() + ".masterWriteTotalLat")
2816        .desc("Per-master write total memory access latency")
2817        .flags(nozero | nonan);
2818
2819    masterWriteAvgLat.name(name() + ".masterWriteAvgLat")
2820        .desc("Per-master write average memory access latency")
2821        .flags(nonan)
2822        .precision(2);
2823
2824    masterWriteAvgLat = masterWriteTotalLat/masterWriteAccesses;
2825
2826    for (int i = 0; i < _system->maxMasters(); i++) {
2827        const std::string master = _system->getMasterName(i);
2828        masterReadBytes.subname(i, master);
2829        masterReadRate.subname(i, master);
2830        masterWriteBytes.subname(i, master);
2831        masterWriteRate.subname(i, master);
2832        masterReadAccesses.subname(i, master);
2833        masterWriteAccesses.subname(i, master);
2834        masterReadTotalLat.subname(i, master);
2835        masterReadAvgLat.subname(i, master);
2836        masterWriteTotalLat.subname(i, master);
2837        masterWriteAvgLat.subname(i, master);
2838    }
2839}
2840
2841void
2842DRAMCtrl::recvFunctional(PacketPtr pkt)
2843{
2844    // rely on the abstract memory
2845    functionalAccess(pkt);
2846}
2847
2848Port &
2849DRAMCtrl::getPort(const string &if_name, PortID idx)
2850{
2851    if (if_name != "port") {
2852        return MemObject::getPort(if_name, idx);
2853    } else {
2854        return port;
2855    }
2856}
2857
2858DrainState
2859DRAMCtrl::drain()
2860{
2861    // if there is anything in any of our internal queues, keep track
2862    // of that as well
2863    if (!(!totalWriteQueueSize && !totalReadQueueSize && respQueue.empty() &&
2864          allRanksDrained())) {
2865
2866        DPRINTF(Drain, "DRAM controller not drained, write: %d, read: %d,"
2867                " resp: %d\n", totalWriteQueueSize, totalReadQueueSize,
2868                respQueue.size());
2869
2870        // the only queue that is not drained automatically over time
2871        // is the write queue, thus kick things into action if needed
2872        if (!totalWriteQueueSize && !nextReqEvent.scheduled()) {
2873            schedule(nextReqEvent, curTick());
2874        }
2875
2876        // also need to kick off events to exit self-refresh
2877        for (auto r : ranks) {
2878            // force self-refresh exit, which in turn will issue auto-refresh
2879            if (r->pwrState == PWR_SREF) {
2880                DPRINTF(DRAM,"Rank%d: Forcing self-refresh wakeup in drain\n",
2881                        r->rank);
2882                r->scheduleWakeUpEvent(tXS);
2883            }
2884        }
2885
2886        return DrainState::Draining;
2887    } else {
2888        return DrainState::Drained;
2889    }
2890}
2891
2892bool
2893DRAMCtrl::allRanksDrained() const
2894{
2895    // true until proven false
2896    bool all_ranks_drained = true;
2897    for (auto r : ranks) {
2898        // then verify that the power state is IDLE ensuring all banks are
2899        // closed and rank is not in a low power state. Also verify that rank
2900        // is idle from a refresh point of view.
2901        all_ranks_drained = r->inPwrIdleState() && r->inRefIdleState() &&
2902            all_ranks_drained;
2903    }
2904    return all_ranks_drained;
2905}
2906
2907void
2908DRAMCtrl::drainResume()
2909{
2910    if (!isTimingMode && system()->isTimingMode()) {
2911        // if we switched to timing mode, kick things into action,
2912        // and behave as if we restored from a checkpoint
2913        startup();
2914    } else if (isTimingMode && !system()->isTimingMode()) {
2915        // if we switch from timing mode, stop the refresh events to
2916        // not cause issues with KVM
2917        for (auto r : ranks) {
2918            r->suspend();
2919        }
2920    }
2921
2922    // update the mode
2923    isTimingMode = system()->isTimingMode();
2924}
2925
2926DRAMCtrl::MemoryPort::MemoryPort(const std::string& name, DRAMCtrl& _memory)
2927    : QueuedSlavePort(name, &_memory, queue), queue(_memory, *this, true),
2928      memory(_memory)
2929{ }
2930
2931AddrRangeList
2932DRAMCtrl::MemoryPort::getAddrRanges() const
2933{
2934    AddrRangeList ranges;
2935    ranges.push_back(memory.getAddrRange());
2936    return ranges;
2937}
2938
2939void
2940DRAMCtrl::MemoryPort::recvFunctional(PacketPtr pkt)
2941{
2942    pkt->pushLabel(memory.name());
2943
2944    if (!queue.trySatisfyFunctional(pkt)) {
2945        // Default implementation of SimpleTimingPort::recvFunctional()
2946        // calls recvAtomic() and throws away the latency; we can save a
2947        // little here by just not calculating the latency.
2948        memory.recvFunctional(pkt);
2949    }
2950
2951    pkt->popLabel();
2952}
2953
2954Tick
2955DRAMCtrl::MemoryPort::recvAtomic(PacketPtr pkt)
2956{
2957    return memory.recvAtomic(pkt);
2958}
2959
2960bool
2961DRAMCtrl::MemoryPort::recvTimingReq(PacketPtr pkt)
2962{
2963    // pass it to the memory controller
2964    return memory.recvTimingReq(pkt);
2965}
2966
2967DRAMCtrl*
2968DRAMCtrlParams::create()
2969{
2970    return new DRAMCtrl(this);
2971}
2972