tport.cc revision 3403:92c08efc9d53 
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    }
48
49    //Then just do an atomic access and throw away the returned latency
50    if (pkt->result != Packet::Success)
51        recvAtomic(pkt);
52}
53
54bool
55SimpleTimingPort::recvTiming(PacketPtr pkt)
56{
57    // If the device is only a slave, it should only be sending
58    // responses, which should never get nacked.  There used to be
59    // code to hanldle nacks here, but I'm pretty sure it didn't work
60    // correctly with the drain code, so that would need to be fixed
61    // if we ever added it back.
62    assert(pkt->result != Packet::Nacked);
63    Tick latency = recvAtomic(pkt);
64    // turn packet around to go back to requester if response expected
65    if (pkt->needsResponse()) {
66        pkt->makeTimingResponse();
67        sendTiming(pkt, latency);
68    }
69    else {
70        if (pkt->cmd != Packet::UpgradeReq)
71        {
72            delete pkt->req;
73            delete pkt;
74        }
75    }
76    return true;
77}
78
79void
80SimpleTimingPort::recvRetry()
81{
82    assert(!transmitList.empty());
83    if (Port::sendTiming(transmitList.front().second)) {
84        transmitList.pop_front();
85        DPRINTF(Bus, "No Longer waiting on retry\n");
86        if (!transmitList.empty()) {
87            Tick time = transmitList.front().first;
88            sendEvent.schedule(time <= curTick ? curTick+1 : time);
89        }
90    }
91
92    if (transmitList.empty() && drainEvent) {
93        drainEvent->process();
94        drainEvent = NULL;
95    }
96}
97
98void
99SimpleTimingPort::sendTiming(PacketPtr pkt, Tick time)
100{
101    if (transmitList.empty()) {
102        assert(!sendEvent.scheduled());
103        sendEvent.schedule(curTick+time);
104    }
105    transmitList.push_back(std::pair<Tick,PacketPtr>(time+curTick,pkt));
106}
107
108void
109SimpleTimingPort::SendEvent::process()
110{
111    assert(port->transmitList.size());
112    assert(port->transmitList.front().first <= curTick);
113    if (port->Port::sendTiming(port->transmitList.front().second)) {
114        //send successful, remove packet
115        port->transmitList.pop_front();
116        if (!port->transmitList.empty()) {
117            Tick time = port->transmitList.front().first;
118            schedule(time <= curTick ? curTick+1 : time);
119        }
120        if (port->transmitList.empty() && port->drainEvent) {
121            port->drainEvent->process();
122            port->drainEvent = NULL;
123        }
124        return;
125    }
126    // send unsuccessful (due to flow control).  Will get retry
127    // callback later; save for then if not already
128    DPRINTF(Bus, "Waiting on retry\n");
129}
130
131
132unsigned int
133SimpleTimingPort::drain(Event *de)
134{
135    if (transmitList.size() == 0)
136        return 0;
137    drainEvent = de;
138    return 1;
139}
140