tport.cc revision 3450 
1/*
2 * Copyright (c) 2006 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Ali Saidi
29 */
30
31#include "mem/tport.hh"
32
33void
34SimpleTimingPort::recvFunctional(PacketPtr pkt)
35{
36    std::list<std::pair<Tick,PacketPtr> >::iterator i = transmitList.begin();
37    std::list<std::pair<Tick,PacketPtr> >::iterator end = transmitList.end();
38    bool done = false;
39
40    while (i != end && !done) {
41        PacketPtr target = i->second;
42        // If the target contains data, and it overlaps the
43        // probed request, need to update data
44        if (target->intersect(pkt))
45            done = fixPacket(pkt, target);
46
47        i++;
48    }
49
50    //Then just do an atomic access and throw away the returned latency
51    if (pkt->result != Packet::Success)
52        recvAtomic(pkt);
53}
54
55bool
56SimpleTimingPort::recvTiming(PacketPtr pkt)
57{
58    // If the device is only a slave, it should only be sending
59    // responses, which should never get nacked.  There used to be
60    // code to hanldle nacks here, but I'm pretty sure it didn't work
61    // correctly with the drain code, so that would need to be fixed
62    // if we ever added it back.
63    assert(pkt->result != Packet::Nacked);
64    Tick latency = recvAtomic(pkt);
65    // turn packet around to go back to requester if response expected
66    if (pkt->needsResponse()) {
67        pkt->makeTimingResponse();
68        sendTiming(pkt, latency);
69    }
70    else {
71        if (pkt->cmd != Packet::UpgradeReq)
72        {
73            delete pkt->req;
74            delete pkt;
75        }
76    }
77    return true;
78}
79
80void
81SimpleTimingPort::recvRetry()
82{
83    assert(!transmitList.empty());
84    if (Port::sendTiming(transmitList.front().second)) {
85        transmitList.pop_front();
86        DPRINTF(Bus, "No Longer waiting on retry\n");
87        if (!transmitList.empty()) {
88            Tick time = transmitList.front().first;
89            sendEvent.schedule(time <= curTick ? curTick+1 : time);
90        }
91    }
92
93    if (transmitList.empty() && drainEvent) {
94        drainEvent->process();
95        drainEvent = NULL;
96    }
97}
98
99void
100SimpleTimingPort::sendTiming(PacketPtr pkt, Tick time)
101{
102    // Nothing is on the list: add it and schedule an event
103    if (transmitList.empty()) {
104        assert(!sendEvent.scheduled());
105        sendEvent.schedule(curTick+time);
106        transmitList.push_back(std::pair<Tick,PacketPtr>(time+curTick,pkt));
107        return;
108    }
109
110    // something is on the list and this belongs at the end
111    if (time+curTick >= transmitList.back().first) {
112        transmitList.push_back(std::pair<Tick,PacketPtr>(time+curTick,pkt));
113        return;
114    }
115    // Something is on the list and this belongs somewhere else
116    std::list<std::pair<Tick,PacketPtr> >::iterator i = transmitList.begin();
117    std::list<std::pair<Tick,PacketPtr> >::iterator end = transmitList.end();
118    bool done = false;
119
120    while (i != end && !done) {
121        if (time+curTick < i->first)
122            transmitList.insert(i,std::pair<Tick,PacketPtr>(time+curTick,pkt));
123        i++;
124    }
125}
126
127void
128SimpleTimingPort::SendEvent::process()
129{
130    assert(port->transmitList.size());
131    assert(port->transmitList.front().first <= curTick);
132    if (port->Port::sendTiming(port->transmitList.front().second)) {
133        //send successful, remove packet
134        port->transmitList.pop_front();
135        if (!port->transmitList.empty()) {
136            Tick time = port->transmitList.front().first;
137            schedule(time <= curTick ? curTick+1 : time);
138        }
139        if (port->transmitList.empty() && port->drainEvent) {
140            port->drainEvent->process();
141            port->drainEvent = NULL;
142        }
143        return;
144    }
145    // send unsuccessful (due to flow control).  Will get retry
146    // callback later; save for then if not already
147    DPRINTF(Bus, "Waiting on retry\n");
148}
149
150
151unsigned int
152SimpleTimingPort::drain(Event *de)
153{
154    if (transmitList.size() == 0)
155        return 0;
156    drainEvent = de;
157    return 1;
158}
159