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/*
* Copyright (c) 2012, 2015, 2017, 2019 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
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* modified or unmodified, in source code or in binary form.
*
* Copyright (c) 2006 The Regents of The University of Michigan
* All rights reserved.
*
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* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
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*
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*/
#include "dev/dma_device.hh"
#include <utility>
#include "base/chunk_generator.hh"
#include "debug/DMA.hh"
#include "debug/Drain.hh"
#include "mem/port_proxy.hh"
#include "sim/clocked_object.hh"
#include "sim/system.hh"
DmaPort::DmaPort(ClockedObject *dev, System *s,
uint32_t sid, uint32_t ssid)
: MasterPort(dev->name() + ".dma", dev),
device(dev), sys(s), masterId(s->getMasterId(dev)),
sendEvent([this]{ sendDma(); }, dev->name()),
pendingCount(0), inRetry(false),
defaultSid(sid),
defaultSSid(ssid)
{ }
void
DmaPort::handleResp(PacketPtr pkt, Tick delay)
{
// should always see a response with a sender state
assert(pkt->isResponse());
// get the DMA sender state
DmaReqState *state = dynamic_cast<DmaReqState*>(pkt->senderState);
assert(state);
DPRINTF(DMA, "Received response %s for addr: %#x size: %d nb: %d," \
" tot: %d sched %d\n",
pkt->cmdString(), pkt->getAddr(), pkt->req->getSize(),
state->numBytes, state->totBytes,
state->completionEvent ?
state->completionEvent->scheduled() : 0);
assert(pendingCount != 0);
pendingCount--;
// update the number of bytes received based on the request rather
// than the packet as the latter could be rounded up to line sizes
state->numBytes += pkt->req->getSize();
assert(state->totBytes >= state->numBytes);
// if we have reached the total number of bytes for this DMA
// request, then signal the completion and delete the sate
if (state->totBytes == state->numBytes) {
if (state->completionEvent) {
delay += state->delay;
device->schedule(state->completionEvent, curTick() + delay);
}
delete state;
}
// delete the packet
delete pkt;
// we might be drained at this point, if so signal the drain event
if (pendingCount == 0)
signalDrainDone();
}
bool
DmaPort::recvTimingResp(PacketPtr pkt)
{
// We shouldn't ever get a cacheable block in Modified state
assert(pkt->req->isUncacheable() ||
!(pkt->cacheResponding() && !pkt->hasSharers()));
handleResp(pkt);
return true;
}
DmaDevice::DmaDevice(const Params *p)
: PioDevice(p), dmaPort(this, sys, p->sid, p->ssid)
{ }
void
DmaDevice::init()
{
if (!dmaPort.isConnected())
panic("DMA port of %s not connected to anything!", name());
PioDevice::init();
}
DrainState
DmaPort::drain()
{
if (pendingCount == 0) {
return DrainState::Drained;
} else {
DPRINTF(Drain, "DmaPort not drained\n");
return DrainState::Draining;
}
}
void
DmaPort::recvReqRetry()
{
assert(transmitList.size());
trySendTimingReq();
}
RequestPtr
DmaPort::dmaAction(Packet::Command cmd, Addr addr, int size, Event *event,
uint8_t *data, uint32_t sid, uint32_t ssid, Tick delay,
Request::Flags flag)
{
// one DMA request sender state for every action, that is then
// split into many requests and packets based on the block size,
// i.e. cache line size
DmaReqState *reqState = new DmaReqState(event, size, delay);
// (functionality added for Table Walker statistics)
// We're only interested in this when there will only be one request.
// For simplicity, we return the last request, which would also be
// the only request in that case.
RequestPtr req = NULL;
DPRINTF(DMA, "Starting DMA for addr: %#x size: %d sched: %d\n", addr, size,
event ? event->scheduled() : -1);
for (ChunkGenerator gen(addr, size, sys->cacheLineSize());
!gen.done(); gen.next()) {
req = std::make_shared<Request>(
gen.addr(), gen.size(), flag, masterId);
req->setStreamId(sid);
req->setSubStreamId(ssid);
req->taskId(ContextSwitchTaskId::DMA);
PacketPtr pkt = new Packet(req, cmd);
// Increment the data pointer on a write
if (data)
pkt->dataStatic(data + gen.complete());
pkt->senderState = reqState;
DPRINTF(DMA, "--Queuing DMA for addr: %#x size: %d\n", gen.addr(),
gen.size());
queueDma(pkt);
}
// in zero time also initiate the sending of the packets we have
// just created, for atomic this involves actually completing all
// the requests
sendDma();
return req;
}
RequestPtr
DmaPort::dmaAction(Packet::Command cmd, Addr addr, int size, Event *event,
uint8_t *data, Tick delay, Request::Flags flag)
{
return dmaAction(cmd, addr, size, event, data,
defaultSid, defaultSSid, delay, flag);
}
void
DmaPort::queueDma(PacketPtr pkt)
{
transmitList.push_back(pkt);
// remember that we have another packet pending, this will only be
// decremented once a response comes back
pendingCount++;
}
void
DmaPort::trySendTimingReq()
{
// send the first packet on the transmit list and schedule the
// following send if it is successful
PacketPtr pkt = transmitList.front();
DPRINTF(DMA, "Trying to send %s addr %#x\n", pkt->cmdString(),
pkt->getAddr());
inRetry = !sendTimingReq(pkt);
if (!inRetry) {
transmitList.pop_front();
DPRINTF(DMA, "-- Done\n");
// if there is more to do, then do so
if (!transmitList.empty())
// this should ultimately wait for as many cycles as the
// device needs to send the packet, but currently the port
// does not have any known width so simply wait a single
// cycle
device->schedule(sendEvent, device->clockEdge(Cycles(1)));
} else {
DPRINTF(DMA, "-- Failed, waiting for retry\n");
}
DPRINTF(DMA, "TransmitList: %d, inRetry: %d\n",
transmitList.size(), inRetry);
}
void
DmaPort::sendDma()
{
// some kind of selcetion between access methods
// more work is going to have to be done to make
// switching actually work
assert(transmitList.size());
if (sys->isTimingMode()) {
// if we are either waiting for a retry or are still waiting
// after sending the last packet, then do not proceed
if (inRetry || sendEvent.scheduled()) {
DPRINTF(DMA, "Can't send immediately, waiting to send\n");
return;
}
trySendTimingReq();
} else if (sys->isAtomicMode()) {
// send everything there is to send in zero time
while (!transmitList.empty()) {
PacketPtr pkt = transmitList.front();
transmitList.pop_front();
DPRINTF(DMA, "Sending DMA for addr: %#x size: %d\n",
pkt->req->getPaddr(), pkt->req->getSize());
Tick lat = sendAtomic(pkt);
handleResp(pkt, lat);
}
} else
panic("Unknown memory mode.");
}
Port &
DmaDevice::getPort(const std::string &if_name, PortID idx)
{
if (if_name == "dma") {
return dmaPort;
}
return PioDevice::getPort(if_name, idx);
}
DmaReadFifo::DmaReadFifo(DmaPort &_port, size_t size,
unsigned max_req_size,
unsigned max_pending,
Request::Flags flags)
: maxReqSize(max_req_size), fifoSize(size),
reqFlags(flags), port(_port),
buffer(size),
nextAddr(0), endAddr(0)
{
freeRequests.resize(max_pending);
for (auto &e : freeRequests)
e.reset(new DmaDoneEvent(this, max_req_size));
}
DmaReadFifo::~DmaReadFifo()
{
for (auto &p : pendingRequests) {
DmaDoneEvent *e(p.release());
if (e->done()) {
delete e;
} else {
// We can't kill in-flight DMAs, so we'll just transfer
// ownership to the event queue so that they get freed
// when they are done.
e->kill();
}
}
}
void
DmaReadFifo::serialize(CheckpointOut &cp) const
{
assert(pendingRequests.empty());
SERIALIZE_CONTAINER(buffer);
SERIALIZE_SCALAR(endAddr);
SERIALIZE_SCALAR(nextAddr);
}
void
DmaReadFifo::unserialize(CheckpointIn &cp)
{
UNSERIALIZE_CONTAINER(buffer);
UNSERIALIZE_SCALAR(endAddr);
UNSERIALIZE_SCALAR(nextAddr);
}
bool
DmaReadFifo::tryGet(uint8_t *dst, size_t len)
{
if (buffer.size() >= len) {
buffer.read(dst, len);
resumeFill();
return true;
} else {
return false;
}
}
void
DmaReadFifo::get(uint8_t *dst, size_t len)
{
const bool success(tryGet(dst, len));
panic_if(!success, "Buffer underrun in DmaReadFifo::get()\n");
}
void
DmaReadFifo::startFill(Addr start, size_t size)
{
assert(atEndOfBlock());
nextAddr = start;
endAddr = start + size;
resumeFill();
}
void
DmaReadFifo::stopFill()
{
// Prevent new DMA requests by setting the next address to the end
// address. Pending requests will still complete.
nextAddr = endAddr;
// Flag in-flight accesses as canceled. This prevents their data
// from being written to the FIFO.
for (auto &p : pendingRequests)
p->cancel();
}
void
DmaReadFifo::resumeFill()
{
// Don't try to fetch more data if we are draining. This ensures
// that the DMA engine settles down before we checkpoint it.
if (drainState() == DrainState::Draining)
return;
const bool old_eob(atEndOfBlock());
if (port.sys->bypassCaches())
resumeFillFunctional();
else
resumeFillTiming();
if (!old_eob && atEndOfBlock())
onEndOfBlock();
}
void
DmaReadFifo::resumeFillFunctional()
{
const size_t fifo_space = buffer.capacity() - buffer.size();
const size_t kvm_watermark = port.sys->cacheLineSize();
if (fifo_space >= kvm_watermark || buffer.capacity() < kvm_watermark) {
const size_t block_remaining = endAddr - nextAddr;
const size_t xfer_size = std::min(fifo_space, block_remaining);
std::vector<uint8_t> tmp_buffer(xfer_size);
assert(pendingRequests.empty());
DPRINTF(DMA, "KVM Bypassing startAddr=%#x xfer_size=%#x " \
"fifo_space=%#x block_remaining=%#x\n",
nextAddr, xfer_size, fifo_space, block_remaining);
port.sys->physProxy.readBlob(nextAddr, tmp_buffer.data(), xfer_size);
buffer.write(tmp_buffer.begin(), xfer_size);
nextAddr += xfer_size;
}
}
void
DmaReadFifo::resumeFillTiming()
{
size_t size_pending(0);
for (auto &e : pendingRequests)
size_pending += e->requestSize();
while (!freeRequests.empty() && !atEndOfBlock()) {
const size_t req_size(std::min(maxReqSize, endAddr - nextAddr));
if (buffer.size() + size_pending + req_size > fifoSize)
break;
DmaDoneEventUPtr event(std::move(freeRequests.front()));
freeRequests.pop_front();
assert(event);
event->reset(req_size);
port.dmaAction(MemCmd::ReadReq, nextAddr, req_size, event.get(),
event->data(), 0, reqFlags);
nextAddr += req_size;
size_pending += req_size;
pendingRequests.emplace_back(std::move(event));
}
}
void
DmaReadFifo::dmaDone()
{
const bool old_active(isActive());
handlePending();
resumeFill();
if (old_active && !isActive())
onIdle();
}
void
DmaReadFifo::handlePending()
{
while (!pendingRequests.empty() && pendingRequests.front()->done()) {
// Get the first finished pending request
DmaDoneEventUPtr event(std::move(pendingRequests.front()));
pendingRequests.pop_front();
if (!event->canceled())
buffer.write(event->data(), event->requestSize());
// Move the event to the list of free requests
freeRequests.emplace_back(std::move(event));
}
if (pendingRequests.empty())
signalDrainDone();
}
DrainState
DmaReadFifo::drain()
{
return pendingRequests.empty() ? DrainState::Drained : DrainState::Draining;
}
DmaReadFifo::DmaDoneEvent::DmaDoneEvent(DmaReadFifo *_parent,
size_t max_size)
: parent(_parent), _done(false), _canceled(false), _data(max_size, 0)
{
}
void
DmaReadFifo::DmaDoneEvent::kill()
{
parent = nullptr;
setFlags(AutoDelete);
}
void
DmaReadFifo::DmaDoneEvent::cancel()
{
_canceled = true;
}
void
DmaReadFifo::DmaDoneEvent::reset(size_t size)
{
assert(size <= _data.size());
_done = false;
_canceled = false;
_requestSize = size;
}
void
DmaReadFifo::DmaDoneEvent::process()
{
if (!parent)
return;
assert(!_done);
_done = true;
parent->dmaDone();
}