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

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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;

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