1 2/* 3 * Copyright (c) 2006 The Regents of The University of Michigan 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions are 8 * met: redistributions of source code must retain the above copyright --- 17 unchanged lines hidden (view full) --- 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30/** 31 * @file Definition of a simple bus bridge without buffering. 32 */ 33 |
34#include <algorithm> |
35 36#include "base/trace.hh" 37#include "mem/bridge.hh" 38#include "sim/builder.hh" 39 |
40Bridge::BridgePort::BridgePort(const std::string &_name, 41 Bridge *_bridge, BridgePort *_otherPort, 42 int _delay, int _queueLimit) 43 : Port(_name), bridge(_bridge), otherPort(_otherPort), 44 delay(_delay), outstandingResponses(0), 45 queueLimit(_queueLimit), sendEvent(this) 46{ 47} 48 49Bridge::Bridge(const std::string &n, int qsa, int qsb, 50 Tick _delay, int write_ack) 51 : MemObject(n), 52 portA(n + "-portA", this, &portB, _delay, qsa), 53 portB(n + "-portB", this, &portA, _delay, qsa), 54 ackWrites(write_ack) 55{ 56} 57 58Port * 59Bridge::getPort(const std::string &if_name) 60{ 61 BridgePort *port; 62 63 if (if_name == "side_a") 64 port = &portA; 65 else if (if_name == "side_b") 66 port = &portB; 67 else 68 return NULL; 69 70 if (port->getPeer() != NULL) 71 panic("bridge side %s already connected to.", if_name); 72 return port; 73} 74 75 |
76void 77Bridge::init() 78{ 79 // Make sure that both sides are connected to. |
80 if (portA.getPeer() == NULL || portB.getPeer() == NULL) |
81 panic("Both ports of bus bridge are not connected to a bus.\n"); 82} 83 84 |
85/** Function called by the port when the bus is receiving a Timing |
86 * transaction.*/ 87bool |
88Bridge::BridgePort::recvTiming(Packet *pkt) |
89{ |
90 DPRINTF(BusBridge, "recvTiming: src %d dest %d addr 0x%x\n", 91 pkt->getSrc(), pkt->getDest(), pkt->getAddr()); |
92 |
93 if (pkt->isResponse()) { 94 // This is a response for a request we forwarded earlier. The 95 // corresponding PacketBuffer should be stored in the packet's 96 // senderState field. 97 PacketBuffer *buf = dynamic_cast<PacketBuffer*>(pkt->senderState); 98 assert(buf != NULL); 99 // set up new packet dest & senderState based on values saved 100 // from original request 101 buf->fixResponse(pkt); 102 DPRINTF(BusBridge, " is response, new dest %d\n", pkt->getDest()); 103 delete buf; |
104 } |
105 |
106 return otherPort->queueForSendTiming(pkt); |
107} 108 |
109 |
110bool 111Bridge::BridgePort::queueForSendTiming(Packet *pkt) |
112{ |
113 if (queueFull()) 114 return false; |
115 |
116 Tick readyTime = curTick + delay; 117 PacketBuffer *buf = new PacketBuffer(pkt, readyTime); 118 119 // If we're about to put this packet at the head of the queue, we 120 // need to schedule an event to do the transmit. Otherwise there 121 // should already be an event scheduled for sending the head 122 // packet. 123 if (sendQueue.empty()) { 124 sendEvent.schedule(readyTime); |
125 } |
126 |
127 sendQueue.push_back(buf); 128 129 // Did we just become blocked? If yes, let other side know. 130 if (queueFull()) 131 otherPort->sendStatusChange(Port::Blocked); 132 133 return true; |
134} 135 136 137void |
138Bridge::BridgePort::finishSend(PacketBuffer *buf) |
139{ |
140 if (buf->expectResponse) { 141 // Must wait for response. We just need to count outstanding 142 // responses (in case we want to cap them); PacketBuffer 143 // pointer will be recovered on response. 144 ++outstandingResponses; 145 DPRINTF(BusBridge, " successful: awaiting response (%d)\n", 146 outstandingResponses); 147 } else { 148 // no response expected... deallocate packet buffer now. 149 DPRINTF(BusBridge, " successful: no response expected\n"); 150 delete buf; 151 } 152 153 // If there are more packets to send, schedule event to try again. 154 if (!sendQueue.empty()) { 155 buf = sendQueue.front(); 156 sendEvent.schedule(std::max(buf->ready, curTick + 1)); 157 } |
158} 159 |
160 |
161void |
162Bridge::BridgePort::trySend() |
163{ |
164 assert(!sendQueue.empty()); 165 166 PacketBuffer *buf = sendQueue.front(); 167 168 assert(buf->ready <= curTick); 169 170 Packet *pkt = buf->pkt; 171 172 DPRINTF(BusBridge, "trySend: origSrc %d dest %d addr 0x%x\n", 173 buf->origSrc, pkt->getDest(), pkt->getAddr()); 174 175 if (sendTiming(pkt)) { 176 // send successful 177 sendQueue.pop_front(); 178 buf->pkt = NULL; // we no longer own packet, so it's not safe to look at it 179 finishSend(buf); 180 } else { 181 DPRINTF(BusBridge, " unsuccessful\n"); 182 } |
183} 184 185 186Packet * 187Bridge::BridgePort::recvRetry() 188{ |
189 PacketBuffer *buf = sendQueue.front(); 190 Packet *pkt = buf->pkt; 191 finishSend(buf); |
192 return pkt; 193} 194 |
195/** Function called by the port when the bus is receiving a Atomic |
196 * transaction.*/ 197Tick |
198Bridge::BridgePort::recvAtomic(Packet *pkt) |
199{ |
200 return otherPort->sendAtomic(pkt) + delay; |
201} 202 |
203/** Function called by the port when the bus is receiving a Functional |
204 * transaction.*/ 205void |
206Bridge::BridgePort::recvFunctional(Packet *pkt) |
207{ |
208 std::list<PacketBuffer*>::iterator i; |
209 bool pktContinue = true; 210 |
211 for (i = sendQueue.begin(); i != sendQueue.end(); ++i) { 212 if (pkt->intersect((*i)->pkt)) { 213 pktContinue &= fixPacket(pkt, (*i)->pkt); |
214 } 215 } 216 |
217 if (pktContinue) { |
218 otherPort->sendFunctional(pkt); |
219 } 220} 221 |
222/** Function called by the port when the bus is receiving a status change.*/ |
223void |
224Bridge::BridgePort::recvStatusChange(Port::Status status) |
225{ 226 if (status == Port::Blocked || status == Port::Unblocked) |
227 return; |
228 |
229 otherPort->sendStatusChange(status); |
230} 231 232void |
233Bridge::BridgePort::getDeviceAddressRanges(AddrRangeList &resp, 234 AddrRangeList &snoop) |
235{ |
236 otherPort->getPeerAddressRanges(resp, snoop); |
237} 238 239BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bridge) 240 241 Param<int> queue_size_a; 242 Param<int> queue_size_b; 243 Param<Tick> delay; 244 Param<bool> write_ack; --- 19 unchanged lines hidden --- |