gem5/util/tlm/sc_master_port.cc
Christian Menard 78e4967b6a misc: Clean up and complete the gem5<->SystemC-TLM bridge [9/10]
The current TLM bridge only provides a Slave Port that allows the gem5
world to send request to the SystemC world. This patch series refractors
and cleans up the existing code, and adds a Master Port that allows the
SystemC world to send requests to the gem5 world.

This patch:
  * Pay for the header delay that the gem5 XBar annotates to packets.

Reviewed at http://reviews.gem5.org/r/3798/

Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
2017-02-09 19:15:48 -05:00

427 lines
12 KiB
C++

/*
* Copyright (c) 2016, Dresden University of Technology (TU Dresden)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER
* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Christian Menard
*/
#include <sstream>
#include "master_transactor.hh"
#include "params/ExternalMaster.hh"
#include "sc_ext.hh"
#include "sc_master_port.hh"
#include "sim/system.hh"
namespace Gem5SystemC
{
PacketPtr
SCMasterPort::generatePacket(tlm::tlm_generic_payload& trans)
{
Request::Flags flags;
auto req = new Request(trans.get_address(), trans.get_data_length(), flags,
owner.masterId);
MemCmd cmd;
switch (trans.get_command()) {
case tlm::TLM_READ_COMMAND:
cmd = MemCmd::ReadReq;
break;
case tlm::TLM_WRITE_COMMAND:
cmd = MemCmd::WriteReq;
break;
default:
SC_REPORT_FATAL("SCMasterPort",
"received transaction with unsupported command");
}
/*
* Allocate a new Packet. The packet will be deleted when it returns from
* the gem5 world as a response.
*/
auto pkt = new Packet(req, cmd);
pkt->dataStatic(trans.get_data_ptr());
return pkt;
}
void
SCMasterPort::destroyPacket(PacketPtr pkt)
{
delete pkt;
}
SCMasterPort::SCMasterPort(const std::string& name_,
const std::string& systemc_name,
ExternalMaster& owner_,
Gem5SimControl& simControl)
: ExternalMaster::Port(name_, owner_),
peq(this, &SCMasterPort::peq_cb),
waitForRetry(false),
pendingRequest(nullptr),
pendingPacket(nullptr),
needToSendRetry(false),
responseInProgress(false),
transactor(nullptr),
simControl(simControl)
{
system =
dynamic_cast<const ExternalMasterParams*>(owner_.params())->system;
}
void
SCMasterPort::bindToTransactor(Gem5MasterTransactor* transactor)
{
sc_assert(this->transactor == nullptr);
this->transactor = transactor;
/*
* Register the TLM non-blocking interface when using gem5 Timing mode and
* the TLM blocking interface when using the gem5 Atomic mode.
* Then the magic (TM) in simple_target_socket automatically transforms
* non-blocking in blocking transactions and vice versa.
*
* NOTE: The mode may change during execution.
*/
if (system->isTimingMode()) {
SC_REPORT_INFO("SCMasterPort", "register non-blocking interface");
transactor->socket.register_nb_transport_fw(this,
&SCMasterPort::nb_transport_fw);
} else if (system->isAtomicMode()) {
SC_REPORT_INFO("SCMasterPort", "register blocking interface");
transactor->socket.register_b_transport(this,
&SCMasterPort::b_transport);
} else {
panic("gem5 operates neither in Timing nor in Atomic mode");
}
transactor->socket.register_transport_dbg(this,
&SCMasterPort::transport_dbg);
}
void
SCMasterPort::checkTransaction(tlm::tlm_generic_payload& trans)
{
if (trans.is_response_error()) {
std::stringstream ss;
ss << "Transaction returned with error, response status = "
<< trans.get_response_string();
SC_REPORT_ERROR("TLM-2", ss.str().c_str());
}
}
tlm::tlm_sync_enum
SCMasterPort::nb_transport_fw(tlm::tlm_generic_payload& trans,
tlm::tlm_phase& phase, sc_core::sc_time& delay)
{
uint64_t adr = trans.get_address();
unsigned len = trans.get_data_length();
unsigned char* byteEnable = trans.get_byte_enable_ptr();
unsigned width = trans.get_streaming_width();
// check the transaction attributes for unsupported features ...
if (byteEnable != 0) {
trans.set_response_status(tlm::TLM_BYTE_ENABLE_ERROR_RESPONSE);
return tlm::TLM_COMPLETED;
}
if (width < len) { // is this a burst request?
trans.set_response_status(tlm::TLM_BURST_ERROR_RESPONSE);
return tlm::TLM_COMPLETED;
}
// ... and queue the valid transaction
trans.acquire();
peq.notify(trans, phase, delay);
return tlm::TLM_ACCEPTED;
}
void
SCMasterPort::peq_cb(tlm::tlm_generic_payload& trans,
const tlm::tlm_phase& phase)
{
// catch up with SystemC time
simControl.catchup();
assert(curTick() == sc_core::sc_time_stamp().value());
switch (phase) {
case tlm::BEGIN_REQ:
handleBeginReq(trans);
break;
case tlm::END_RESP:
handleEndResp(trans);
break;
default:
panic("unimplemented phase in callback");
}
// the functions called above may have scheduled gem5 events
// -> notify the event loop handler
simControl.notify();
}
void
SCMasterPort::handleBeginReq(tlm::tlm_generic_payload& trans)
{
sc_assert(!waitForRetry);
sc_assert(pendingRequest == nullptr);
sc_assert(pendingPacket == nullptr);
trans.acquire();
PacketPtr pkt = nullptr;
Gem5Extension* extension = nullptr;
trans.get_extension(extension);
// If there is an extension, this transaction was initiated by the gem5
// world and we can pipe through the original packet. Otherwise, we
// generate a new packet based on the transaction.
if (extension != nullptr) {
extension->setPipeThrough();
pkt = extension->getPacket();
} else {
pkt = generatePacket(trans);
}
auto tlmSenderState = new TlmSenderState(trans);
pkt->pushSenderState(tlmSenderState);
if (sendTimingReq(pkt)) { // port is free -> send END_REQ immediately
sendEndReq(trans);
trans.release();
} else { // port is blocked -> wait for retry before sending END_REQ
waitForRetry = true;
pendingRequest = &trans;
pendingPacket = pkt;
}
}
void
SCMasterPort::handleEndResp(tlm::tlm_generic_payload& trans)
{
sc_assert(responseInProgress);
responseInProgress = false;
checkTransaction(trans);
if (needToSendRetry) {
sendRetryResp();
needToSendRetry = false;
}
}
void
SCMasterPort::sendEndReq(tlm::tlm_generic_payload& trans)
{
tlm::tlm_phase phase = tlm::END_REQ;
auto delay = sc_core::SC_ZERO_TIME;
auto status = transactor->socket->nb_transport_bw(trans, phase, delay);
panic_if(status != tlm::TLM_ACCEPTED,
"Unexpected status after sending END_REQ");
}
void
SCMasterPort::b_transport(tlm::tlm_generic_payload& trans,
sc_core::sc_time& t)
{
Gem5Extension* extension = nullptr;
trans.get_extension(extension);
PacketPtr pkt = nullptr;
// If there is an extension, this transaction was initiated by the gem5
// world and we can pipe through the original packet.
if (extension != nullptr) {
extension->setPipeThrough();
pkt = extension->getPacket();
} else {
pkt = generatePacket(trans);
}
Tick ticks = sendAtomic(pkt);
// send an atomic request to gem5
panic_if(pkt->needsResponse() && !pkt->isResponse(),
"Packet sending failed!\n");
// one tick is a pico second
auto delay =
sc_core::sc_time((double)(ticks / SimClock::Int::ps), sc_core::SC_PS);
// update time
t += delay;
if (extension != nullptr)
destroyPacket(pkt);
trans.set_response_status(tlm::TLM_OK_RESPONSE);
}
unsigned int
SCMasterPort::transport_dbg(tlm::tlm_generic_payload& trans)
{
Gem5Extension* extension = nullptr;
trans.get_extension(extension);
// If there is an extension, this transaction was initiated by the gem5
// world and we can pipe through the original packet.
if (extension != nullptr) {
extension->setPipeThrough();
sendFunctional(extension->getPacket());
} else {
auto pkt = generatePacket(trans);
sendFunctional(pkt);
destroyPacket(pkt);
}
return trans.get_data_length();
}
bool
SCMasterPort::get_direct_mem_ptr(tlm::tlm_generic_payload& trans,
tlm::tlm_dmi& dmi_data)
{
return false;
}
bool
SCMasterPort::recvTimingResp(PacketPtr pkt)
{
// exclusion rule
// We need to Wait for END_RESP before sending next BEGIN_RESP
if (responseInProgress) {
sc_assert(!needToSendRetry);
needToSendRetry = true;
return false;
}
sc_assert(pkt->isResponse());
/*
* Pay for annotated transport delays.
*
* See recvTimingReq in sc_slave_port.cc for a detailed description.
*/
auto delay = sc_core::sc_time::from_value(pkt->payloadDelay);
// reset the delays
pkt->payloadDelay = 0;
pkt->headerDelay = 0;
auto tlmSenderState = dynamic_cast<TlmSenderState*>(pkt->popSenderState());
sc_assert(tlmSenderState != nullptr);
auto& trans = tlmSenderState->trans;
Gem5Extension* extension = nullptr;
trans.get_extension(extension);
// clean up
delete tlmSenderState;
// If there is an extension the packet was piped through and we must not
// delete it. The packet travels back with the transaction.
if (extension == nullptr)
destroyPacket(pkt);
else
sc_assert(extension->isPipeThrough());
sendBeginResp(trans, delay);
trans.release();
return true;
}
void
SCMasterPort::sendBeginResp(tlm::tlm_generic_payload& trans,
sc_core::sc_time& delay)
{
tlm::tlm_phase phase = tlm::BEGIN_RESP;
trans.set_response_status(tlm::TLM_OK_RESPONSE);
auto status = transactor->socket->nb_transport_bw(trans, phase, delay);
if (status == tlm::TLM_COMPLETED ||
status == tlm::TLM_UPDATED && phase == tlm::END_RESP) {
// transaction completed -> no need to wait for tlm::END_RESP
responseInProgress = false;
} else if (status == tlm::TLM_ACCEPTED) {
// we need to wait for tlm::END_RESP
responseInProgress = true;
} else {
panic("Unexpected status after sending BEGIN_RESP");
}
}
void
SCMasterPort::recvReqRetry()
{
sc_assert(waitForRetry);
sc_assert(pendingRequest != nullptr);
sc_assert(pendingPacket != nullptr);
if (sendTimingReq(pendingPacket)) {
waitForRetry = false;
pendingPacket = nullptr;
auto& trans = *pendingRequest;
sendEndReq(trans);
trans.release();
pendingRequest = nullptr;
}
}
void
SCMasterPort::recvRangeChange()
{
SC_REPORT_WARNING("SCMasterPort",
"received address range change but ignored it");
}
ExternalMaster::Port*
SCMasterPortHandler::getExternalPort(const std::string &name,
ExternalMaster &owner,
const std::string &port_data)
{
// Create and register a new SystemC master port
auto* port = new SCMasterPort(name, port_data, owner, control);
control.registerMasterPort(port_data, port);
return port;
}
} // namespace Gem5SystemC