1/*
2 * Copyright (c) 2012, 2015, 2017 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) 2006 The Regents of The University of Michigan
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
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: Ali Saidi
41 * Nathan Binkert
42 * Andreas Hansson
43 * Andreas Sandberg
44 */
45
46#include "dev/dma_device.hh"
47
48#include <utility>
49
50#include "base/chunk_generator.hh"
51#include "debug/DMA.hh"
52#include "debug/Drain.hh"
53#include "mem/port_proxy.hh"
54#include "sim/system.hh"
55
56DmaPort::DmaPort(MemObject *dev, System *s)
57 : MasterPort(dev->name() + ".dma", dev),
58 device(dev), sys(s), masterId(s->getMasterId(dev)),
59 sendEvent([this]{ sendDma(); }, dev->name()),
60 pendingCount(0), inRetry(false)
61{ }
62
63void
64DmaPort::handleResp(PacketPtr pkt, Tick delay)
65{
66 // should always see a response with a sender state
67 assert(pkt->isResponse());
68
69 // get the DMA sender state
70 DmaReqState *state = dynamic_cast<DmaReqState*>(pkt->senderState);
71 assert(state);
72
73 DPRINTF(DMA, "Received response %s for addr: %#x size: %d nb: %d," \
74 " tot: %d sched %d\n",
75 pkt->cmdString(), pkt->getAddr(), pkt->req->getSize(),
76 state->numBytes, state->totBytes,
77 state->completionEvent ?
78 state->completionEvent->scheduled() : 0);
79
80 assert(pendingCount != 0);
81 pendingCount--;
82
83 // update the number of bytes received based on the request rather
84 // than the packet as the latter could be rounded up to line sizes
85 state->numBytes += pkt->req->getSize();
86 assert(state->totBytes >= state->numBytes);
87
88 // if we have reached the total number of bytes for this DMA
89 // request, then signal the completion and delete the sate
90 if (state->totBytes == state->numBytes) {
91 if (state->completionEvent) {
92 delay += state->delay;
93 device->schedule(state->completionEvent, curTick() + delay);
94 }
95 delete state;
96 }
97
98 // delete the packet
99 delete pkt;
100
101 // we might be drained at this point, if so signal the drain event
102 if (pendingCount == 0)
103 signalDrainDone();
104}
105
106bool
107DmaPort::recvTimingResp(PacketPtr pkt)
108{
109 // We shouldn't ever get a cacheable block in Modified state
110 assert(pkt->req->isUncacheable() ||
111 !(pkt->cacheResponding() && !pkt->hasSharers()));
112
113 handleResp(pkt);
114
115 return true;
116}
117
118DmaDevice::DmaDevice(const Params *p)
119 : PioDevice(p), dmaPort(this, sys)
120{ }
121
122void
123DmaDevice::init()
124{
125 if (!dmaPort.isConnected())
126 panic("DMA port of %s not connected to anything!", name());
127 PioDevice::init();
128}
129
130DrainState
131DmaPort::drain()
132{
133 if (pendingCount == 0) {
134 return DrainState::Drained;
135 } else {
136 DPRINTF(Drain, "DmaPort not drained\n");
137 return DrainState::Draining;
138 }
139}
140
141void
142DmaPort::recvReqRetry()
143{
144 assert(transmitList.size());
145 trySendTimingReq();
146}
147
148RequestPtr
149DmaPort::dmaAction(Packet::Command cmd, Addr addr, int size, Event *event,
150 uint8_t *data, Tick delay, Request::Flags flag)
151{
152 // one DMA request sender state for every action, that is then
153 // split into many requests and packets based on the block size,
154 // i.e. cache line size
155 DmaReqState *reqState = new DmaReqState(event, size, delay);
156
157 // (functionality added for Table Walker statistics)
158 // We're only interested in this when there will only be one request.
159 // For simplicity, we return the last request, which would also be
160 // the only request in that case.
161 RequestPtr req = NULL;
162
163 DPRINTF(DMA, "Starting DMA for addr: %#x size: %d sched: %d\n", addr, size,
164 event ? event->scheduled() : -1);
165 for (ChunkGenerator gen(addr, size, sys->cacheLineSize());
166 !gen.done(); gen.next()) {
167
168 req = std::make_shared<Request>(
169 gen.addr(), gen.size(), flag, masterId);
170
171 req->taskId(ContextSwitchTaskId::DMA);
172 PacketPtr pkt = new Packet(req, cmd);
173
174 // Increment the data pointer on a write
175 if (data)
176 pkt->dataStatic(data + gen.complete());
177
178 pkt->senderState = reqState;
179
180 DPRINTF(DMA, "--Queuing DMA for addr: %#x size: %d\n", gen.addr(),
181 gen.size());
182 queueDma(pkt);
183 }
184
185 // in zero time also initiate the sending of the packets we have
186 // just created, for atomic this involves actually completing all
187 // the requests
188 sendDma();
189
190 return req;
191}
192
193void
194DmaPort::queueDma(PacketPtr pkt)
195{
196 transmitList.push_back(pkt);
197
198 // remember that we have another packet pending, this will only be
199 // decremented once a response comes back
200 pendingCount++;
201}
202
203void
204DmaPort::trySendTimingReq()
205{
206 // send the first packet on the transmit list and schedule the
207 // following send if it is successful
208 PacketPtr pkt = transmitList.front();
209
210 DPRINTF(DMA, "Trying to send %s addr %#x\n", pkt->cmdString(),
211 pkt->getAddr());
212
213 inRetry = !sendTimingReq(pkt);
214 if (!inRetry) {
215 transmitList.pop_front();
216 DPRINTF(DMA, "-- Done\n");
217 // if there is more to do, then do so
218 if (!transmitList.empty())
219 // this should ultimately wait for as many cycles as the
220 // device needs to send the packet, but currently the port
221 // does not have any known width so simply wait a single
222 // cycle
223 device->schedule(sendEvent, device->clockEdge(Cycles(1)));
224 } else {
225 DPRINTF(DMA, "-- Failed, waiting for retry\n");
226 }
227
228 DPRINTF(DMA, "TransmitList: %d, inRetry: %d\n",
229 transmitList.size(), inRetry);
230}
231
232void
233DmaPort::sendDma()
234{
235 // some kind of selcetion between access methods
236 // more work is going to have to be done to make
237 // switching actually work
238 assert(transmitList.size());
239
240 if (sys->isTimingMode()) {
241 // if we are either waiting for a retry or are still waiting
242 // after sending the last packet, then do not proceed
243 if (inRetry || sendEvent.scheduled()) {
244 DPRINTF(DMA, "Can't send immediately, waiting to send\n");
245 return;
246 }
247
248 trySendTimingReq();
249 } else if (sys->isAtomicMode()) {
250 // send everything there is to send in zero time
251 while (!transmitList.empty()) {
252 PacketPtr pkt = transmitList.front();
253 transmitList.pop_front();
254
255 DPRINTF(DMA, "Sending DMA for addr: %#x size: %d\n",
256 pkt->req->getPaddr(), pkt->req->getSize());
257 Tick lat = sendAtomic(pkt);
258
259 handleResp(pkt, lat);
260 }
261 } else
262 panic("Unknown memory mode.");
263}
264
265Port &
266DmaDevice::getPort(const std::string &if_name, PortID idx)
267{
268 if (if_name == "dma") {
269 return dmaPort;
270 }
271 return PioDevice::getPort(if_name, idx);
272}
273
274
275
276
277
278DmaReadFifo::DmaReadFifo(DmaPort &_port, size_t size,
279 unsigned max_req_size,
280 unsigned max_pending,
281 Request::Flags flags)
282 : maxReqSize(max_req_size), fifoSize(size),
283 reqFlags(flags), port(_port),
284 buffer(size),
285 nextAddr(0), endAddr(0)
286{
287 freeRequests.resize(max_pending);
288 for (auto &e : freeRequests)
289 e.reset(new DmaDoneEvent(this, max_req_size));
290
291}
292
293DmaReadFifo::~DmaReadFifo()
294{
295 for (auto &p : pendingRequests) {
296 DmaDoneEvent *e(p.release());
297
298 if (e->done()) {
299 delete e;
300 } else {
301 // We can't kill in-flight DMAs, so we'll just transfer
302 // ownership to the event queue so that they get freed
303 // when they are done.
304 e->kill();
305 }
306 }
307}
308
309void
310DmaReadFifo::serialize(CheckpointOut &cp) const
311{
312 assert(pendingRequests.empty());
313
314 SERIALIZE_CONTAINER(buffer);
315 SERIALIZE_SCALAR(endAddr);
316 SERIALIZE_SCALAR(nextAddr);
317}
318
319void
320DmaReadFifo::unserialize(CheckpointIn &cp)
321{
322 UNSERIALIZE_CONTAINER(buffer);
323 UNSERIALIZE_SCALAR(endAddr);
324 UNSERIALIZE_SCALAR(nextAddr);
325}
326
327bool
328DmaReadFifo::tryGet(uint8_t *dst, size_t len)
329{
330 if (buffer.size() >= len) {
331 buffer.read(dst, len);
332 resumeFill();
333 return true;
334 } else {
335 return false;
336 }
337}
338
339void
340DmaReadFifo::get(uint8_t *dst, size_t len)
341{
342 const bool success(tryGet(dst, len));
343 panic_if(!success, "Buffer underrun in DmaReadFifo::get()\n");
344}
345
346void
347DmaReadFifo::startFill(Addr start, size_t size)
348{
349 assert(atEndOfBlock());
350
351 nextAddr = start;
352 endAddr = start + size;
353 resumeFill();
354}
355
356void
357DmaReadFifo::stopFill()
358{
359 // Prevent new DMA requests by setting the next address to the end
360 // address. Pending requests will still complete.
361 nextAddr = endAddr;
362
363 // Flag in-flight accesses as canceled. This prevents their data
364 // from being written to the FIFO.
365 for (auto &p : pendingRequests)
366 p->cancel();
367}
368
369void
370DmaReadFifo::resumeFill()
371{
372 // Don't try to fetch more data if we are draining. This ensures
373 // that the DMA engine settles down before we checkpoint it.
374 if (drainState() == DrainState::Draining)
375 return;
376
377 const bool old_eob(atEndOfBlock());
378
379 if (port.sys->bypassCaches())
380 resumeFillFunctional();
381 else
382 resumeFillTiming();
383
384 if (!old_eob && atEndOfBlock())
385 onEndOfBlock();
386}
387
388void
389DmaReadFifo::resumeFillFunctional()
390{
391 const size_t fifo_space = buffer.capacity() - buffer.size();
392 const size_t kvm_watermark = port.sys->cacheLineSize();
393 if (fifo_space >= kvm_watermark || buffer.capacity() < kvm_watermark) {
394 const size_t block_remaining = endAddr - nextAddr;
395 const size_t xfer_size = std::min(fifo_space, block_remaining);
396 std::vector<uint8_t> tmp_buffer(xfer_size);
397
398 assert(pendingRequests.empty());
399 DPRINTF(DMA, "KVM Bypassing startAddr=%#x xfer_size=%#x " \
400 "fifo_space=%#x block_remaining=%#x\n",
401 nextAddr, xfer_size, fifo_space, block_remaining);
402
403 port.sys->physProxy.readBlob(nextAddr, tmp_buffer.data(), xfer_size);
404 buffer.write(tmp_buffer.begin(), xfer_size);
405 nextAddr += xfer_size;
406 }
407}
408
409void
410DmaReadFifo::resumeFillTiming()
411{
412 size_t size_pending(0);
413 for (auto &e : pendingRequests)
414 size_pending += e->requestSize();
415
416 while (!freeRequests.empty() && !atEndOfBlock()) {
417 const size_t req_size(std::min(maxReqSize, endAddr - nextAddr));
418 if (buffer.size() + size_pending + req_size > fifoSize)
419 break;
420
421 DmaDoneEventUPtr event(std::move(freeRequests.front()));
422 freeRequests.pop_front();
423 assert(event);
424
425 event->reset(req_size);
426 port.dmaAction(MemCmd::ReadReq, nextAddr, req_size, event.get(),
427 event->data(), 0, reqFlags);
428 nextAddr += req_size;
429 size_pending += req_size;
430
431 pendingRequests.emplace_back(std::move(event));
432 }
433}
434
435void
436DmaReadFifo::dmaDone()
437{
438 const bool old_active(isActive());
439
440 handlePending();
441 resumeFill();
442
443 if (old_active && !isActive())
444 onIdle();
445}
446
447void
448DmaReadFifo::handlePending()
449{
450 while (!pendingRequests.empty() && pendingRequests.front()->done()) {
451 // Get the first finished pending request
452 DmaDoneEventUPtr event(std::move(pendingRequests.front()));
453 pendingRequests.pop_front();
454
455 if (!event->canceled())
456 buffer.write(event->data(), event->requestSize());
457
458 // Move the event to the list of free requests
459 freeRequests.emplace_back(std::move(event));
460 }
461
462 if (pendingRequests.empty())
463 signalDrainDone();
464}
465
466DrainState
467DmaReadFifo::drain()
468{
469 return pendingRequests.empty() ? DrainState::Drained : DrainState::Draining;
470}
471
472
473DmaReadFifo::DmaDoneEvent::DmaDoneEvent(DmaReadFifo *_parent,
474 size_t max_size)
475 : parent(_parent), _done(false), _canceled(false), _data(max_size, 0)
476{
477}
478
479void
480DmaReadFifo::DmaDoneEvent::kill()
481{
482 parent = nullptr;
483 setFlags(AutoDelete);
484}
485
486void
487DmaReadFifo::DmaDoneEvent::cancel()
488{
489 _canceled = true;
490}
491
492void
493DmaReadFifo::DmaDoneEvent::reset(size_t size)
494{
495 assert(size <= _data.size());
496 _done = false;
497 _canceled = false;
498 _requestSize = size;
499}
500
501void
502DmaReadFifo::DmaDoneEvent::process()
503{
504 if (!parent)
505 return;
506
507 assert(!_done);
508 _done = true;
509 parent->dmaDone();
510}