diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/dev/arm/RealView.py | 31 | ||||
| -rw-r--r-- | src/mem/Bridge.py | 16 | ||||
| -rw-r--r-- | src/mem/bridge.cc | 381 | ||||
| -rw-r--r-- | src/mem/bridge.hh | 324 |
4 files changed, 551 insertions, 201 deletions
diff --git a/src/dev/arm/RealView.py b/src/dev/arm/RealView.py index 96f3c8a61..cd7744362 100644 --- a/src/dev/arm/RealView.py +++ b/src/dev/arm/RealView.py @@ -1,4 +1,4 @@ -# Copyright (c) 2009 ARM Limited +# Copyright (c) 2009-2011 ARM Limited # All rights reserved. # # The license below extends only to copyright in the software and shall @@ -177,12 +177,18 @@ class RealViewPBX(RealView): rtc_fake = AmbaFake(pio_addr=0x10017000, amba_id=0x41031) - # Attach I/O devices that are on chip - def attachOnChipIO(self, bus): + # Attach I/O devices that are on chip and also set the appropriate + # ranges for the bridge + def attachOnChipIO(self, bus, bridge): self.gic.pio = bus.port self.l2x0_fake.pio = bus.port self.a9scu.pio = bus.port self.local_cpu_timer.pio = bus.port + # Bridge ranges based on excluding what is part of on-chip I/O + # (gic, l2x0, a9scu, local_cpu_timer) + bridge.ranges = [AddrRange(self.realview_io.pio_addr, + self.a9scu.pio_addr - 1), + AddrRange(self.flash_fake.pio_addr, Addr.max)] # Attach I/O devices to specified bus object. Can't do this # earlier, since the bus object itself is typically defined at the @@ -248,10 +254,16 @@ class RealViewEB(RealView): - # Attach I/O devices that are on chip - def attachOnChipIO(self, bus): + # Attach I/O devices that are on chip and also set the appropriate + # ranges for the bridge + def attachOnChipIO(self, bus, bridge): self.gic.pio = bus.port self.l2x0_fake.pio = bus.port + # Bridge ranges based on excluding what is part of on-chip I/O + # (gic, l2x0) + bridge.ranges = [AddrRange(self.realview_io.pio_addr, + self.gic.cpu_addr - 1), + AddrRange(self.flash_fake.pio_addr, Addr.max)] # Attach I/O devices to specified bus object. Can't do this # earlier, since the bus object itself is typically defined at the @@ -329,10 +341,15 @@ class VExpress_ELT(RealView): usb_fake = IsaFake(pio_addr=0xFB000000, pio_size=0x1ffff) - # Attach I/O devices that are on chip - def attachOnChipIO(self, bus): + # Attach I/O devices that are on chip and also set the appropriate + # ranges for the bridge + def attachOnChipIO(self, bus, bridge): self.gic.pio = bus.port self.a9scu.pio = bus.port + # Bridge ranges based on excluding what is part of on-chip I/O + # (gic, a9scu) + bridge.ranges = [AddrRange(self.pci_cfg_base, self.a9scu.pio_addr - 1), + AddrRange(self.local_cpu_timer.pio_addr, Addr.max)] # Attach I/O devices to specified bus object. Can't do this # earlier, since the bus object itself is typically defined at the diff --git a/src/mem/Bridge.py b/src/mem/Bridge.py index b48e1684d..38b344613 100644 --- a/src/mem/Bridge.py +++ b/src/mem/Bridge.py @@ -31,16 +31,12 @@ from MemObject import MemObject class Bridge(MemObject): type = 'Bridge' - side_a = Port('Side A port') - side_b = Port('Side B port') - req_size_a = Param.Int(16, "The number of requests to buffer") - req_size_b = Param.Int(16, "The number of requests to buffer") - resp_size_a = Param.Int(16, "The number of requests to buffer") - resp_size_b = Param.Int(16, "The number of requests to buffer") + slave = Port('Slave port') + master = Port('Master port') + req_size = Param.Int(16, "The number of requests to buffer") + resp_size = Param.Int(16, "The number of requests to buffer") delay = Param.Latency('0ns', "The latency of this bridge") nack_delay = Param.Latency('0ns', "The latency of this bridge") write_ack = Param.Bool(False, "Should this bridge ack writes") - filter_ranges_a = VectorParam.AddrRange([], - "What addresses shouldn't be passed through the side of the bridge") - filter_ranges_b = VectorParam.AddrRange([], - "What addresses shouldn't be passed through the side of the bridge") + ranges = VectorParam.AddrRange([AllMemory], + "Address ranges to pass through the bridge") diff --git a/src/mem/bridge.cc b/src/mem/bridge.cc index 71cbcb76c..b48662118 100644 --- a/src/mem/bridge.cc +++ b/src/mem/bridge.cc @@ -1,5 +1,16 @@ - /* + * Copyright (c) 2011 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 + * unmodified and in its entirety in all distributions of the software, + * modified or unmodified, in source code or in binary form. + * * Copyright (c) 2006 The Regents of The University of Michigan * All rights reserved. * @@ -28,54 +39,63 @@ * * Authors: Ali Saidi * Steve Reinhardt + * Andreas Hansson */ /** * @file - * Definition of a simple bus bridge without buffering. + * Implementation of a memory-mapped bus bridge that connects a master + * and a slave through a request and response queue. */ -#include <algorithm> - -#include "base/range_ops.hh" #include "base/trace.hh" #include "debug/BusBridge.hh" #include "mem/bridge.hh" #include "params/Bridge.hh" -Bridge::BridgePort::BridgePort(const std::string &_name, - Bridge *_bridge, BridgePort *_otherPort, - int _delay, int _nack_delay, int _req_limit, - int _resp_limit, - std::vector<Range<Addr> > filter_ranges) - : Port(_name, _bridge), bridge(_bridge), otherPort(_otherPort), - delay(_delay), nackDelay(_nack_delay), filterRanges(filter_ranges), - outstandingResponses(0), queuedRequests(0), inRetry(false), - reqQueueLimit(_req_limit), respQueueLimit(_resp_limit), sendEvent(this) +Bridge::BridgeSlavePort::BridgeSlavePort(const std::string &_name, + Bridge* _bridge, + BridgeMasterPort* _masterPort, + int _delay, int _nack_delay, + int _resp_limit, + std::vector<Range<Addr> > _ranges) + : Port(_name, _bridge), bridge(_bridge), masterPort(_masterPort), + delay(_delay), nackDelay(_nack_delay), + ranges(_ranges.begin(), _ranges.end()), + outstandingResponses(0), inRetry(false), + respQueueLimit(_resp_limit), sendEvent(this) +{ +} + +Bridge::BridgeMasterPort::BridgeMasterPort(const std::string &_name, + Bridge* _bridge, + BridgeSlavePort* _slavePort, + int _delay, int _req_limit) + : Port(_name, _bridge), bridge(_bridge), slavePort(_slavePort), + delay(_delay), inRetry(false), reqQueueLimit(_req_limit), sendEvent(this) { } Bridge::Bridge(Params *p) : MemObject(p), - portA(p->name + "-portA", this, &portB, p->delay, p->nack_delay, - p->req_size_a, p->resp_size_a, p->filter_ranges_a), - portB(p->name + "-portB", this, &portA, p->delay, p->nack_delay, - p->req_size_b, p->resp_size_b, p->filter_ranges_b), + slavePort(p->name + "-slave", this, &masterPort, p->delay, + p->nack_delay, p->resp_size, p->ranges), + masterPort(p->name + "-master", this, &slavePort, p->delay, p->req_size), ackWrites(p->write_ack), _params(p) { if (ackWrites) panic("No support for acknowledging writes\n"); } -Port * +Port* Bridge::getPort(const std::string &if_name, int idx) { - BridgePort *port; + Port* port; - if (if_name == "side_a") - port = &portA; - else if (if_name == "side_b") - port = &portB; + if (if_name == "slave") + port = &slavePort; + else if (if_name == "master") + port = &masterPort; else return NULL; @@ -89,106 +109,133 @@ Bridge::getPort(const std::string &if_name, int idx) void Bridge::init() { - // Make sure that both sides are connected to. - if (!portA.isConnected() || !portB.isConnected()) + // make sure both sides are connected and have the same block size + if (!slavePort.isConnected() || !masterPort.isConnected()) fatal("Both ports of bus bridge are not connected to a bus.\n"); - if (portA.peerBlockSize() != portB.peerBlockSize()) - fatal("port A size %d, port B size %d \n " \ + if (slavePort.peerBlockSize() != masterPort.peerBlockSize()) + fatal("Slave port size %d, master port size %d \n " \ "Busses don't have the same block size... Not supported.\n", - portA.peerBlockSize(), portB.peerBlockSize()); + slavePort.peerBlockSize(), masterPort.peerBlockSize()); + + // notify the master side of our address ranges + slavePort.sendRangeChange(); } bool -Bridge::BridgePort::respQueueFull() +Bridge::BridgeSlavePort::respQueueFull() { - assert(outstandingResponses >= 0 && outstandingResponses <= respQueueLimit); - return outstandingResponses >= respQueueLimit; + return outstandingResponses == respQueueLimit; } bool -Bridge::BridgePort::reqQueueFull() +Bridge::BridgeMasterPort::reqQueueFull() { - assert(queuedRequests >= 0 && queuedRequests <= reqQueueLimit); - return queuedRequests >= reqQueueLimit; + return requestQueue.size() == reqQueueLimit; } -/** Function called by the port when the bus is receiving a Timing - * transaction.*/ bool -Bridge::BridgePort::recvTiming(PacketPtr pkt) +Bridge::BridgeMasterPort::recvTiming(PacketPtr pkt) { + // should only see responses on the master side + assert(pkt->isResponse()); + + // all checks are done when the request is accepted on the slave + // side, so we are guaranteed to have space for the response + DPRINTF(BusBridge, "recvTiming: src %d dest %d addr 0x%x\n", - pkt->getSrc(), pkt->getDest(), pkt->getAddr()); + pkt->getSrc(), pkt->getDest(), pkt->getAddr()); + + DPRINTF(BusBridge, "Request queue size: %d\n", requestQueue.size()); - DPRINTF(BusBridge, "Local queue size: %d outreq: %d outresp: %d\n", - sendQueue.size(), queuedRequests, outstandingResponses); - DPRINTF(BusBridge, "Remote queue size: %d outreq: %d outresp: %d\n", - otherPort->sendQueue.size(), otherPort->queuedRequests, - otherPort->outstandingResponses); + slavePort->queueForSendTiming(pkt); + + return true; +} - if (pkt->isRequest() && otherPort->reqQueueFull()) { - DPRINTF(BusBridge, "Remote queue full, nacking\n"); +bool +Bridge::BridgeSlavePort::recvTiming(PacketPtr pkt) +{ + // should only see requests on the slave side + assert(pkt->isRequest()); + + DPRINTF(BusBridge, "recvTiming: src %d dest %d addr 0x%x\n", + pkt->getSrc(), pkt->getDest(), pkt->getAddr()); + + DPRINTF(BusBridge, "Response queue size: %d outresp: %d\n", + responseQueue.size(), outstandingResponses); + + if (masterPort->reqQueueFull()) { + DPRINTF(BusBridge, "Request queue full, nacking\n"); nackRequest(pkt); return true; } if (pkt->needsResponse()) { if (respQueueFull()) { - DPRINTF(BusBridge, "Local queue full, no space for response, nacking\n"); - DPRINTF(BusBridge, "queue size: %d outreq: %d outstanding resp: %d\n", - sendQueue.size(), queuedRequests, outstandingResponses); + DPRINTF(BusBridge, + "Response queue full, no space for response, nacking\n"); + DPRINTF(BusBridge, + "queue size: %d outstanding resp: %d\n", + responseQueue.size(), outstandingResponses); nackRequest(pkt); return true; } else { DPRINTF(BusBridge, "Request Needs response, reserving space\n"); + assert(outstandingResponses != respQueueLimit); ++outstandingResponses; } } - otherPort->queueForSendTiming(pkt); + masterPort->queueForSendTiming(pkt); return true; } void -Bridge::BridgePort::nackRequest(PacketPtr pkt) +Bridge::BridgeSlavePort::nackRequest(PacketPtr pkt) { // Nack the packet pkt->makeTimingResponse(); pkt->setNacked(); - //put it on the list to send + // The Nack packets are stored in the response queue just like any + // other response, but they do not occupy any space as this is + // tracked by the outstandingResponses, this guarantees space for + // the Nack packets, but implicitly means we have an (unrealistic) + // unbounded Nack queue. + + // put it on the list to send Tick readyTime = curTick() + nackDelay; PacketBuffer *buf = new PacketBuffer(pkt, readyTime, true); // nothing on the list, add it and we're done - if (sendQueue.empty()) { + if (responseQueue.empty()) { assert(!sendEvent.scheduled()); bridge->schedule(sendEvent, readyTime); - sendQueue.push_back(buf); + responseQueue.push_back(buf); return; } assert(sendEvent.scheduled() || inRetry); // does it go at the end? - if (readyTime >= sendQueue.back()->ready) { - sendQueue.push_back(buf); + if (readyTime >= responseQueue.back()->ready) { + responseQueue.push_back(buf); return; } // ok, somewhere in the middle, fun - std::list<PacketBuffer*>::iterator i = sendQueue.begin(); - std::list<PacketBuffer*>::iterator end = sendQueue.end(); - std::list<PacketBuffer*>::iterator begin = sendQueue.begin(); + std::list<PacketBuffer*>::iterator i = responseQueue.begin(); + std::list<PacketBuffer*>::iterator end = responseQueue.end(); + std::list<PacketBuffer*>::iterator begin = responseQueue.begin(); bool done = false; while (i != end && !done) { if (readyTime < (*i)->ready) { if (i == begin) bridge->reschedule(sendEvent, readyTime); - sendQueue.insert(i,buf); + responseQueue.insert(i,buf); done = true; } i++; @@ -196,51 +243,60 @@ Bridge::BridgePort::nackRequest(PacketPtr pkt) assert(done); } - void -Bridge::BridgePort::queueForSendTiming(PacketPtr pkt) +Bridge::BridgeMasterPort::queueForSendTiming(PacketPtr pkt) { - if (pkt->isResponse()) { - // This is a response for a request we forwarded earlier. The - // corresponding PacketBuffer should be stored in the packet's - // senderState field. - - PacketBuffer *buf = dynamic_cast<PacketBuffer*>(pkt->senderState); - assert(buf != NULL); - // set up new packet dest & senderState based on values saved - // from original request - buf->fixResponse(pkt); - - DPRINTF(BusBridge, "response, new dest %d\n", pkt->getDest()); - delete buf; + Tick readyTime = curTick() + delay; + PacketBuffer *buf = new PacketBuffer(pkt, readyTime); + + // If we're about to put this packet at the head of the queue, we + // need to schedule an event to do the transmit. Otherwise there + // should already be an event scheduled for sending the head + // packet. + if (requestQueue.empty()) { + bridge->schedule(sendEvent, readyTime); } + assert(requestQueue.size() != reqQueueLimit); - if (pkt->isRequest()) { - ++queuedRequests; - } + requestQueue.push_back(buf); +} +void +Bridge::BridgeSlavePort::queueForSendTiming(PacketPtr pkt) +{ + // This is a response for a request we forwarded earlier. The + // corresponding PacketBuffer should be stored in the packet's + // senderState field. + PacketBuffer *buf = dynamic_cast<PacketBuffer*>(pkt->senderState); + assert(buf != NULL); + // set up new packet dest & senderState based on values saved + // from original request + buf->fixResponse(pkt); + + DPRINTF(BusBridge, "response, new dest %d\n", pkt->getDest()); + delete buf; Tick readyTime = curTick() + delay; - PacketBuffer *buf = new PacketBuffer(pkt, readyTime); + buf = new PacketBuffer(pkt, readyTime); // If we're about to put this packet at the head of the queue, we // need to schedule an event to do the transmit. Otherwise there // should already be an event scheduled for sending the head // packet. - if (sendQueue.empty()) { + if (responseQueue.empty()) { bridge->schedule(sendEvent, readyTime); } - sendQueue.push_back(buf); + responseQueue.push_back(buf); } void -Bridge::BridgePort::trySend() +Bridge::BridgeMasterPort::trySend() { - assert(!sendQueue.empty()); + assert(!requestQueue.empty()); - PacketBuffer *buf = sendQueue.front(); + PacketBuffer *buf = requestQueue.front(); assert(buf->ready <= curTick()); @@ -249,107 +305,194 @@ Bridge::BridgePort::trySend() DPRINTF(BusBridge, "trySend: origSrc %d dest %d addr 0x%x\n", buf->origSrc, pkt->getDest(), pkt->getAddr()); - bool wasReq = pkt->isRequest(); - bool was_nacked_here = buf->nackedHere; - // If the send was successful, make sure sender state was set to NULL // otherwise we could get a NACK back of a packet that didn't expect a // response and we would try to use freed memory. Packet::SenderState *old_sender_state = pkt->senderState; - if (pkt->isRequest() && !buf->expectResponse) + if (!buf->expectResponse) pkt->senderState = NULL; if (sendTiming(pkt)) { // send successful - sendQueue.pop_front(); - buf->pkt = NULL; // we no longer own packet, so it's not safe to look at it + requestQueue.pop_front(); + // we no longer own packet, so it's not safe to look at it + buf->pkt = NULL; - if (buf->expectResponse) { - // Must wait for response - DPRINTF(BusBridge, " successful: awaiting response (%d)\n", - outstandingResponses); - } else { + if (!buf->expectResponse) { // no response expected... deallocate packet buffer now. DPRINTF(BusBridge, " successful: no response expected\n"); delete buf; } - if (wasReq) - --queuedRequests; - else if (!was_nacked_here) + // If there are more packets to send, schedule event to try again. + if (!requestQueue.empty()) { + buf = requestQueue.front(); + DPRINTF(BusBridge, "Scheduling next send\n"); + bridge->schedule(sendEvent, std::max(buf->ready, curTick() + 1)); + } + } else { + DPRINTF(BusBridge, " unsuccessful\n"); + pkt->senderState = old_sender_state; + inRetry = true; + } + + DPRINTF(BusBridge, "trySend: request queue size: %d\n", + requestQueue.size()); +} + +void +Bridge::BridgeSlavePort::trySend() +{ + assert(!responseQueue.empty()); + + PacketBuffer *buf = responseQueue.front(); + + assert(buf->ready <= curTick()); + + PacketPtr pkt = buf->pkt; + + DPRINTF(BusBridge, "trySend: origSrc %d dest %d addr 0x%x\n", + buf->origSrc, pkt->getDest(), pkt->getAddr()); + + bool was_nacked_here = buf->nackedHere; + + // no need to worry about the sender state since we are not + // modifying it + + if (sendTiming(pkt)) { + DPRINTF(BusBridge, " successful\n"); + // send successful + responseQueue.pop_front(); + // this is a response... deallocate packet buffer now. + delete buf; + + if (!was_nacked_here) { + assert(outstandingResponses != 0); --outstandingResponses; + } // If there are more packets to send, schedule event to try again. - if (!sendQueue.empty()) { - buf = sendQueue.front(); + if (!responseQueue.empty()) { + buf = responseQueue.front(); DPRINTF(BusBridge, "Scheduling next send\n"); bridge->schedule(sendEvent, std::max(buf->ready, curTick() + 1)); } } else { DPRINTF(BusBridge, " unsuccessful\n"); - pkt->senderState = old_sender_state; inRetry = true; } - DPRINTF(BusBridge, "trySend: queue size: %d outreq: %d outstanding resp: %d\n", - sendQueue.size(), queuedRequests, outstandingResponses); + DPRINTF(BusBridge, "trySend: queue size: %d outstanding resp: %d\n", + responseQueue.size(), outstandingResponses); } +void +Bridge::BridgeMasterPort::recvRetry() +{ + inRetry = false; + Tick nextReady = requestQueue.front()->ready; + if (nextReady <= curTick()) + trySend(); + else + bridge->schedule(sendEvent, nextReady); +} void -Bridge::BridgePort::recvRetry() +Bridge::BridgeSlavePort::recvRetry() { inRetry = false; - Tick nextReady = sendQueue.front()->ready; + Tick nextReady = responseQueue.front()->ready; if (nextReady <= curTick()) trySend(); else bridge->schedule(sendEvent, nextReady); } -/** Function called by the port when the bus is receiving a Atomic - * transaction.*/ Tick -Bridge::BridgePort::recvAtomic(PacketPtr pkt) +Bridge::BridgeMasterPort::recvAtomic(PacketPtr pkt) { - return delay + otherPort->sendAtomic(pkt); + // master port should never receive any atomic access (panic only + // works once the other side, i.e. the busses, respects this) + // + //panic("Master port on %s got a recvAtomic\n", bridge->name()); + return 0; +} + +Tick +Bridge::BridgeSlavePort::recvAtomic(PacketPtr pkt) +{ + return delay + masterPort->sendAtomic(pkt); } -/** Function called by the port when the bus is receiving a Functional - * transaction.*/ void -Bridge::BridgePort::recvFunctional(PacketPtr pkt) +Bridge::BridgeMasterPort::recvFunctional(PacketPtr pkt) +{ + // master port should never receive any functional access (panic + // only works once the other side, i.e. the busses, respect this) + + // panic("Master port on %s got a recvFunctional\n", bridge->name()); +} + +void +Bridge::BridgeSlavePort::recvFunctional(PacketPtr pkt) { std::list<PacketBuffer*>::iterator i; pkt->pushLabel(name()); - for (i = sendQueue.begin(); i != sendQueue.end(); ++i) { + // check the response queue + for (i = responseQueue.begin(); i != responseQueue.end(); ++i) { if (pkt->checkFunctional((*i)->pkt)) { pkt->makeResponse(); return; } } + // also check the master port's request queue + if (masterPort->checkFunctional(pkt)) { + return; + } + pkt->popLabel(); // fall through if pkt still not satisfied - otherPort->sendFunctional(pkt); + masterPort->sendFunctional(pkt); +} + +bool +Bridge::BridgeMasterPort::checkFunctional(PacketPtr pkt) +{ + bool found = false; + std::list<PacketBuffer*>::iterator i = requestQueue.begin(); + + while(i != requestQueue.end() && !found) { + if (pkt->checkFunctional((*i)->pkt)) { + pkt->makeResponse(); + found = true; + } + ++i; + } + + return found; } /** Function called by the port when the bridge is receiving a range change.*/ void -Bridge::BridgePort::recvRangeChange() +Bridge::BridgeMasterPort::recvRangeChange() +{ + // no need to forward as the bridge has a fixed set of ranges +} + +void +Bridge::BridgeSlavePort::recvRangeChange() { - otherPort->sendRangeChange(); + // is a slave port so do nothing } AddrRangeList -Bridge::BridgePort::getAddrRanges() +Bridge::BridgeSlavePort::getAddrRanges() { - AddrRangeList ranges = otherPort->getPeer()->getAddrRanges(); - FilterRangeList(filterRanges, ranges); return ranges; } diff --git a/src/mem/bridge.hh b/src/mem/bridge.hh index a3fa1f8f6..d389c0a5e 100644 --- a/src/mem/bridge.hh +++ b/src/mem/bridge.hh @@ -1,4 +1,16 @@ /* + * Copyright (c) 2011 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 + * unmodified and in its entirety in all distributions of the software, + * modified or unmodified, in source code or in binary form. + * * Copyright (c) 2006 The Regents of The University of Michigan * All rights reserved. * @@ -27,11 +39,13 @@ * * Authors: Ali Saidi * Steve Reinhardt + * Andreas Hansson */ /** * @file - * Declaration of a simple bus bridge object with no buffering + * Declaration of a memory-mapped bus bridge that connects a master + * and a slave through a request and response queue. */ #ifndef __MEM_BRIDGE_HH__ @@ -49,90 +63,232 @@ #include "params/Bridge.hh" #include "sim/eventq.hh" +/** + * A bridge is used to interface two different busses (or in general a + * memory-mapped master and slave), with buffering for requests and + * responses. The bridge has a fixed delay for packets passing through + * it and responds to a fixed set of address ranges. + * + * The bridge comprises a slave port and a master port, that buffer + * outgoing responses and requests respectively. Buffer space is + * reserved when a request arrives, also reserving response space + * before forwarding the request. An incoming request is always + * accepted (recvTiming returns true), but is potentially NACKed if + * there is no request space or response space. + */ class Bridge : public MemObject { protected: - /** Declaration of the buses port type, one will be instantiated for each - of the interfaces connecting to the bus. */ - class BridgePort : public Port + + /** + * A packet buffer stores packets along with their sender state + * and scheduled time for transmission. + */ + class PacketBuffer : public Packet::SenderState, public FastAlloc { + + public: + Tick ready; + PacketPtr pkt; + bool nackedHere; + Packet::SenderState *origSenderState; + short origSrc; + bool expectResponse; + + PacketBuffer(PacketPtr _pkt, Tick t, bool nack = false) + : ready(t), pkt(_pkt), nackedHere(nack), + origSenderState(_pkt->senderState), + origSrc(nack ? _pkt->getDest() : _pkt->getSrc() ), + expectResponse(_pkt->needsResponse() && !nack) + + { + if (!pkt->isResponse() && !nack) + pkt->senderState = this; + } + + void fixResponse(PacketPtr pkt) + { + assert(pkt->senderState == this); + pkt->setDest(origSrc); + pkt->senderState = origSenderState; + } + }; + + // Forward declaration to allow the slave port to have a pointer + class BridgeMasterPort; + + /** + * The port on the side that receives requests and sends + * responses. The slave port has a set of address ranges that it + * is responsible for. The slave port also has a buffer for the + * responses not yet sent. + */ + class BridgeSlavePort : public Port { + + private: + /** A pointer to the bridge to which this port belongs. */ Bridge *bridge; /** - * Pointer to the port on the other side of the bridge + * Pointer to the master port on the other side of the bridge * (connected to the other bus). */ - BridgePort *otherPort; + BridgeMasterPort* masterPort; - /** Minimum delay though this bridge. */ + /** Minimum request delay though this bridge. */ Tick delay; - /** Min delay to respond to a nack. */ + /** Min delay to respond with a nack. */ Tick nackDelay; - /** Pass ranges from one side of the bridge to the other? */ - std::vector<Range<Addr> > filterRanges; + /** Address ranges to pass through the bridge */ + AddrRangeList ranges; + + /** + * Response packet queue. Response packets are held in this + * queue for a specified delay to model the processing delay + * of the bridge. + */ + std::list<PacketBuffer*> responseQueue; - class PacketBuffer : public Packet::SenderState, public FastAlloc { + /** Counter to track the outstanding responses. */ + unsigned int outstandingResponses; + + /** If we're waiting for a retry to happen. */ + bool inRetry; + + /** Max queue size for reserved responses. */ + unsigned int respQueueLimit; + + /** + * Is this side blocked from accepting new response packets. + * + * @return true if the reserved space has reached the set limit + */ + bool respQueueFull(); + + /** + * Turn the request packet into a NACK response and put it in + * the response queue and schedule its transmission. + * + * @param pkt the request packet to NACK + */ + void nackRequest(PacketPtr pkt); + + /** + * Handle send event, scheduled when the packet at the head of + * the response queue is ready to transmit (for timing + * accesses only). + */ + void trySend(); + + /** + * Private class for scheduling sending of responses from the + * response queue. + */ + class SendEvent : public Event + { + BridgeSlavePort *port; public: - Tick ready; - PacketPtr pkt; - bool nackedHere; - Packet::SenderState *origSenderState; - short origSrc; - bool expectResponse; - - PacketBuffer(PacketPtr _pkt, Tick t, bool nack = false) - : ready(t), pkt(_pkt), nackedHere(nack), - origSenderState(_pkt->senderState), - origSrc(nack ? _pkt->getDest() : _pkt->getSrc() ), - expectResponse(_pkt->needsResponse() && !nack) - - { - if (!pkt->isResponse() && !nack) - pkt->senderState = this; - } - - void fixResponse(PacketPtr pkt) - { - assert(pkt->senderState == this); - pkt->setDest(origSrc); - pkt->senderState = origSenderState; - } + SendEvent(BridgeSlavePort *p) : port(p) {} + virtual void process() { port->trySend(); } + virtual const char *description() const { return "bridge send"; } }; + /** Send event for the response queue. */ + SendEvent sendEvent; + + public: + /** - * Outbound packet queue. Packets are held in this queue for a - * specified delay to model the processing delay of the - * bridge. + * Constructor for the BridgeSlavePort. + * + * @param _name the port name including the owner + * @param _bridge the structural owner + * @param _masterPort the master port on the other side of the bridge + * @param _delay the delay from seeing a response to sending it + * @param _nack_delay the delay from a NACK to sending the response + * @param _resp_limit the size of the response queue + * @param _ranges a number of address ranges to forward */ - std::list<PacketBuffer*> sendQueue; + BridgeSlavePort(const std::string &_name, Bridge *_bridge, + BridgeMasterPort* _masterPort, int _delay, + int _nack_delay, int _resp_limit, + std::vector<Range<Addr> > _ranges); - int outstandingResponses; - int queuedRequests; + /** + * Queue a response packet to be sent out later and also schedule + * a send if necessary. + * + * @param pkt a response to send out after a delay + */ + void queueForSendTiming(PacketPtr pkt); - /** If we're waiting for a retry to happen.*/ - bool inRetry; + protected: - /** Max queue size for outbound packets */ - int reqQueueLimit; + /** When receiving a timing request from the peer port, + pass it to the bridge. */ + virtual bool recvTiming(PacketPtr pkt); - /** Max queue size for reserved responses. */ - int respQueueLimit; + /** When receiving a retry request from the peer port, + pass it to the bridge. */ + virtual void recvRetry(); + + /** When receiving a Atomic requestfrom the peer port, + pass it to the bridge. */ + virtual Tick recvAtomic(PacketPtr pkt); + + /** When receiving a Functional request from the peer port, + pass it to the bridge. */ + virtual void recvFunctional(PacketPtr pkt); /** - * Is this side blocked from accepting outbound packets? + * When receiving a range change on the slave side do nothing. */ - bool respQueueFull(); - bool reqQueueFull(); + virtual void recvRangeChange(); - void queueForSendTiming(PacketPtr pkt); + /** When receiving a address range request the peer port, + pass it to the bridge. */ + virtual AddrRangeList getAddrRanges(); + }; - void finishSend(PacketBuffer *buf); - void nackRequest(PacketPtr pkt); + /** + * Port on the side that forwards requests and receives + * responses. The master port has a buffer for the requests not + * yet sent. + */ + class BridgeMasterPort : public Port + { + + private: + + /** A pointer to the bridge to which this port belongs. */ + Bridge* bridge; + + /** + * Pointer to the slave port on the other side of the bridge + * (connected to the other bus). + */ + BridgeSlavePort* slavePort; + + /** Minimum delay though this bridge. */ + Tick delay; + + /** + * Request packet queue. Request packets are held in this + * queue for a specified delay to model the processing delay + * of the bridge. + */ + std::list<PacketBuffer*> requestQueue; + + /** If we're waiting for a retry to happen. */ + bool inRetry; + + /** Max queue size for request packets */ + unsigned int reqQueueLimit; /** * Handle send event, scheduled when the packet at the head of @@ -141,24 +297,62 @@ class Bridge : public MemObject */ void trySend(); + /** + * Private class for scheduling sending of requests from the + * request queue. + */ class SendEvent : public Event { - BridgePort *port; + BridgeMasterPort *port; public: - SendEvent(BridgePort *p) : port(p) {} + SendEvent(BridgeMasterPort *p) : port(p) {} virtual void process() { port->trySend(); } virtual const char *description() const { return "bridge send"; } }; + /** Send event for the request queue. */ SendEvent sendEvent; public: - /** Constructor for the BusPort.*/ - BridgePort(const std::string &_name, Bridge *_bridge, - BridgePort *_otherPort, int _delay, int _nack_delay, - int _req_limit, int _resp_limit, - std::vector<Range<Addr> > filter_ranges); + + /** + * Constructor for the BridgeMasterPort. + * + * @param _name the port name including the owner + * @param _bridge the structural owner + * @param _slavePort the slave port on the other side of the bridge + * @param _delay the delay from seeing a request to sending it + * @param _req_limit the size of the request queue + */ + BridgeMasterPort(const std::string &_name, Bridge *_bridge, + BridgeSlavePort* _slavePort, int _delay, + int _req_limit); + + /** + * Is this side blocked from accepting new request packets. + * + * @return true if the occupied space has reached the set limit + */ + bool reqQueueFull(); + + /** + * Queue a request packet to be sent out later and also schedule + * a send if necessary. + * + * @param pkt a request to send out after a delay + */ + void queueForSendTiming(PacketPtr pkt); + + /** + * Check a functional request against the packets in our + * request queue. + * + * @param pkt packet to check against + * + * @return true if we find a match + */ + bool checkFunctional(PacketPtr pkt); protected: @@ -182,13 +376,13 @@ class Bridge : public MemObject * When receiving a range change, pass it through the bridge. */ virtual void recvRangeChange(); - - /** When receiving a address range request the peer port, - pass it to the bridge. */ - virtual AddrRangeList getAddrRanges(); }; - BridgePort portA, portB; + /** Slave port of the bridge. */ + BridgeSlavePort slavePort; + + /** Master port of the bridge. */ + BridgeMasterPort masterPort; /** If this bridge should acknowledge writes. */ bool ackWrites; |