bridge.cc revision 2632:1bb2f91485ea 
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
9 * notice, this list of conditions and the following disclaimer;
10 * redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution;
13 * neither the name of the copyright holders nor the names of its
14 * contributors may be used to endorse or promote products derived from
15 * this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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
35#include "base/trace.hh"
36#include "mem/bridge.hh"
37#include "sim/builder.hh"
38
39void
40Bridge::init()
41{
42    // Make sure that both sides are connected to.
43    if (sideA == NULL || sideB == NULL)
44        panic("Both ports of bus bridge are not connected to a bus.\n");
45}
46
47
48/** Function called by the port when the bus is recieving a Timing
49 * transaction.*/
50bool
51Bridge::recvTiming(Packet *pkt, Side id)
52{
53    if (blockedA && id == SideA)
54        return false;
55    if (blockedB && id == SideB)
56        return false;
57
58    if (delay) {
59        if (!sendEvent.scheduled())
60            sendEvent.schedule(curTick + delay);
61        if (id == SideA) {
62            inboundA.push_back(std::make_pair<Packet*, Tick>(pkt, curTick));
63            blockCheck(SideA);
64        } else {
65            inboundB.push_back(std::make_pair<Packet*, Tick>(pkt, curTick));
66            blockCheck(SideB);
67        }
68    } else {
69        if (id == SideB) {
70            sideA->sendPkt(pkt);
71            blockCheck(SideB);
72        } else {
73            sideB->sendPkt(pkt);
74            blockCheck(SideA);
75        }
76    }
77    return true;
78
79}
80
81void
82Bridge::blockCheck(Side id)
83{
84    /* Check that we still have buffer space available. */
85    if (id == SideB) {
86        if (sideA->numQueued() + inboundB.size() >= queueSizeA && !blockedB) {
87            sideB->sendStatusChange(Port::Blocked);
88            blockedB = true;
89        } else if (sideA->numQueued() + inboundB.size() < queueSizeA && blockedB) {
90            sideB->sendStatusChange(Port::Unblocked);
91            blockedB = false;
92        }
93    } else {
94        if (sideB->numQueued() + inboundA.size() >= queueSizeB && !blockedA) {
95            sideA->sendStatusChange(Port::Blocked);
96            blockedA = true;
97        } else if (sideB->numQueued() + inboundA.size() < queueSizeB && blockedA) {
98            sideA->sendStatusChange(Port::Unblocked);
99            blockedA = false;
100        }
101    }
102}
103
104void Bridge::timerEvent()
105{
106    Tick t = 0;
107
108    assert(inboundA.size() || inboundB.size());
109    if (inboundA.size()) {
110        while (inboundA.front().second <= curTick + delay){
111            sideB->sendPkt(inboundA.front());
112            inboundA.pop_front();
113        }
114        if (inboundA.size())
115            t = inboundA.front().second + delay;
116    }
117    if (inboundB.size()) {
118        while (inboundB.front().second <= curTick + delay){
119            sideB->sendPkt(inboundA.front());
120            inboundB.pop_front();
121        }
122        if (inboundB.size())
123            if (t == 0)
124               t = inboundB.front().second + delay;
125            else
126               t = std::min(t,inboundB.front().second + delay);
127    } else {
128        panic("timerEvent() called but nothing to do?");
129    }
130
131    if (t != 0)
132        sendEvent.schedule(t);
133}
134
135
136void
137Bridge::BridgePort::sendPkt(Packet *pkt)
138{
139    if (!sendTiming(pkt))
140        outbound.push_back(std::make_pair<Packet*,Tick>(pkt, curTick));
141}
142
143void
144Bridge::BridgePort::sendPkt(std::pair<Packet*, Tick> p)
145{
146    if (!sendTiming(p.first))
147        outbound.push_back(p);
148}
149
150
151Packet *
152Bridge::BridgePort::recvRetry()
153{
154    Packet *pkt;
155    assert(outbound.size() > 0);
156    assert(outbound.front().second >= curTick + bridge->delay);
157    pkt = outbound.front().first;
158    outbound.pop_front();
159    bridge->blockCheck(side);
160    return pkt;
161}
162
163/** Function called by the port when the bus is recieving a Atomic
164 * transaction.*/
165Tick
166Bridge::recvAtomic(Packet *pkt, Side id)
167{
168    pkt->time += delay;
169
170    if (id == SideA)
171        return sideB->sendAtomic(pkt);
172    else
173        return sideA->sendAtomic(pkt);
174}
175
176/** Function called by the port when the bus is recieving a Functional
177 * transaction.*/
178void
179Bridge::recvFunctional(Packet *pkt, Side id)
180{
181    pkt->time += delay;
182    std::list<std::pair<Packet*, Tick> >::iterator i;
183    bool pktContinue = true;
184
185    for(i = inboundA.begin();  i != inboundA.end(); ++i) {
186        if (pkt->intersect(i->first)) {
187            pktContinue &= fixPacket(pkt, i->first);
188        }
189    }
190
191    for(i = inboundB.begin();  i != inboundB.end(); ++i) {
192        if (pkt->intersect(i->first)) {
193            pktContinue &= fixPacket(pkt, i->first);
194        }
195    }
196
197    for(i = sideA->outbound.begin();  i != sideA->outbound.end(); ++i) {
198        if (pkt->intersect(i->first)) {
199            pktContinue &= fixPacket(pkt, i->first);
200        }
201    }
202
203    for(i = sideB->outbound.begin();  i != sideB->outbound.end(); ++i) {
204        if (pkt->intersect(i->first)) {
205            pktContinue &= fixPacket(pkt, i->first);
206        }
207    }
208
209    if (pktContinue) {
210        if (id == SideA)
211            sideB->sendFunctional(pkt);
212        else
213            sideA->sendFunctional(pkt);
214    }
215}
216
217/** Function called by the port when the bus is recieving a status change.*/
218void
219Bridge::recvStatusChange(Port::Status status, Side id)
220{
221    if (status == Port::Blocked || status == Port::Unblocked)
222        return ;
223
224    if (id == SideA)
225        sideB->sendStatusChange(status);
226    else
227        sideA->sendStatusChange(status);
228}
229
230void
231Bridge::addressRanges(AddrRangeList &resp, AddrRangeList &snoop, Side id)
232{
233    if (id == SideA)
234        sideB->getPeerAddressRanges(resp, snoop);
235    else
236        sideA->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;
245
246END_DECLARE_SIM_OBJECT_PARAMS(Bridge)
247
248BEGIN_INIT_SIM_OBJECT_PARAMS(Bridge)
249
250    INIT_PARAM(queue_size_a, "The size of the queue for data coming into side a"),
251    INIT_PARAM(queue_size_b, "The size of the queue for data coming into side b"),
252    INIT_PARAM(delay, "The miminum delay to cross this bridge"),
253    INIT_PARAM(write_ack, "Acknowledge any writes that are received.")
254
255END_INIT_SIM_OBJECT_PARAMS(Bridge)
256
257CREATE_SIM_OBJECT(Bridge)
258{
259    return new Bridge(getInstanceName(), queue_size_a, queue_size_b, delay,
260            write_ack);
261}
262
263REGISTER_SIM_OBJECT("Bridge", Bridge)
264