tport.cc revision 3353:495bb0a961f2 
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<PacketPtr>::iterator i = transmitList.begin();
37    std::list<PacketPtr>::iterator end = transmitList.end();
38
39    while (i != end) {
40        PacketPtr target = *i;
41        // If the target contains data, and it overlaps the
42        // probed request, need to update data
43        if (target->intersect(pkt))
44            fixPacket(pkt, target);
45
46    }
47
48    //Then just do an atomic access and throw away the returned latency
49    if (pkt->result != Packet::Success)
50        recvAtomic(pkt);
51}
52
53bool
54SimpleTimingPort::recvTiming(PacketPtr pkt)
55{
56    // If the device is only a slave, it should only be sending
57    // responses, which should never get nacked.  There used to be
58    // code to hanldle nacks here, but I'm pretty sure it didn't work
59    // correctly with the drain code, so that would need to be fixed
60    // if we ever added it back.
61    assert(pkt->result != Packet::Nacked);
62    Tick latency = recvAtomic(pkt);
63    // turn packet around to go back to requester if response expected
64    if (pkt->needsResponse()) {
65        pkt->makeTimingResponse();
66        sendTimingLater(pkt, latency);
67    }
68    else {
69        if (pkt->cmd != Packet::UpgradeReq)
70        {
71            delete pkt->req;
72            delete pkt;
73        }
74    }
75    return true;
76}
77
78void
79SimpleTimingPort::recvRetry()
80{
81    assert(outTiming > 0);
82    assert(!transmitList.empty());
83    if (sendTiming(transmitList.front())) {
84        transmitList.pop_front();
85        outTiming--;
86        DPRINTF(Bus, "No Longer waiting on retry\n");
87        if (!transmitList.empty())
88            sendTimingLater(transmitList.front(), 1);
89    }
90
91    if (transmitList.empty() && drainEvent) {
92        drainEvent->process();
93        drainEvent = NULL;
94    }
95}
96
97void
98SimpleTimingPort::SendEvent::process()
99{
100    assert(port->outTiming > 0);
101    if (!port->transmitList.empty() && port->transmitList.front() != packet) {
102        //We are not the head of the list
103        port->transmitList.push_back(packet);
104    } else if (port->sendTiming(packet)) {
105        // send successful
106        if (port->transmitList.size()) {
107            port->transmitList.pop_front();
108            port->outTiming--;
109           if (!port->transmitList.empty())
110                port->sendTimingLater(port->transmitList.front(), 1);
111        }
112        if (port->transmitList.empty() && port->drainEvent) {
113            port->drainEvent->process();
114            port->drainEvent = NULL;
115        }
116    } else {
117        // send unsuccessful (due to flow control).  Will get retry
118        // callback later; save for then if not already
119        DPRINTF(Bus, "Waiting on retry\n");
120        if (!(port->transmitList.front() == packet))
121            port->transmitList.push_back(packet);
122    }
123}
124
125
126unsigned int
127SimpleTimingPort::drain(Event *de)
128{
129    if (outTiming == 0 && transmitList.size() == 0)
130        return 0;
131    drainEvent = de;
132    return 1;
133}
134