noncoherent_xbar.cc revision 9092 
1/*
2 * Copyright (c) 2011-2012 ARM Limited
3 * All rights reserved
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder.  You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2006 The Regents of The University of Michigan
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Ali Saidi
41 *          Andreas Hansson
42 *          William Wang
43 */
44
45/**
46 * @file
47 * Definition of a bus object.
48 */
49
50#include "base/misc.hh"
51#include "base/trace.hh"
52#include "debug/Bus.hh"
53#include "debug/BusAddrRanges.hh"
54#include "debug/NoncoherentBus.hh"
55#include "mem/noncoherent_bus.hh"
56
57NoncoherentBus::NoncoherentBus(const NoncoherentBusParams *p)
58    : BaseBus(p), layer(*this, ".layer", p->clock)
59{
60    // create the ports based on the size of the master and slave
61    // vector ports, and the presence of the default port, the ports
62    // are enumerated starting from zero
63    for (int i = 0; i < p->port_master_connection_count; ++i) {
64        std::string portName = csprintf("%s-p%d", name(), i);
65        MasterPort* bp = new NoncoherentBusMasterPort(portName, *this, i);
66        masterPorts.push_back(bp);
67    }
68
69    // see if we have a default slave device connected and if so add
70    // our corresponding master port
71    if (p->port_default_connection_count) {
72        defaultPortID = masterPorts.size();
73        std::string portName = csprintf("%s-default", name());
74        MasterPort* bp = new NoncoherentBusMasterPort(portName, *this,
75                                                      defaultPortID);
76        masterPorts.push_back(bp);
77    }
78
79    // create the slave ports, once again starting at zero
80    for (int i = 0; i < p->port_slave_connection_count; ++i) {
81        std::string portName = csprintf("%s-p%d", name(), i);
82        SlavePort* bp = new NoncoherentBusSlavePort(portName, *this, i);
83        slavePorts.push_back(bp);
84    }
85
86    clearPortCache();
87}
88
89bool
90NoncoherentBus::recvTimingReq(PacketPtr pkt, PortID slave_port_id)
91{
92    // determine the source port based on the id
93    SlavePort *src_port = slavePorts[slave_port_id];
94
95    // we should never see express snoops on a non-coherent bus
96    assert(!pkt->isExpressSnoop());
97
98    // test if the bus should be considered occupied for the current
99    // port
100    if (!layer.tryTiming(src_port)) {
101        DPRINTF(NoncoherentBus, "recvTimingReq: src %s %s 0x%x BUSY\n",
102                src_port->name(), pkt->cmdString(), pkt->getAddr());
103        return false;
104    }
105
106    DPRINTF(NoncoherentBus, "recvTimingReq: src %s %s 0x%x\n",
107            src_port->name(), pkt->cmdString(), pkt->getAddr());
108
109    // set the source port for routing of the response
110    pkt->setSrc(slave_port_id);
111
112    Tick headerFinishTime = calcPacketTiming(pkt);
113    Tick packetFinishTime = pkt->finishTime;
114
115    // since it is a normal request, determine the destination
116    // based on the address and attempt to send the packet
117    bool success = masterPorts[findPort(pkt->getAddr())]->sendTimingReq(pkt);
118
119    if (!success)  {
120        // inhibited packets should never be forced to retry
121        assert(!pkt->memInhibitAsserted());
122
123        DPRINTF(NoncoherentBus, "recvTimingReq: src %s %s 0x%x RETRY\n",
124                src_port->name(), pkt->cmdString(), pkt->getAddr());
125
126        layer.failedTiming(src_port, headerFinishTime);
127
128        return false;
129    }
130
131    layer.succeededTiming(packetFinishTime);
132
133    return true;
134}
135
136bool
137NoncoherentBus::recvTimingResp(PacketPtr pkt, PortID master_port_id)
138{
139    // determine the source port based on the id
140    MasterPort *src_port = masterPorts[master_port_id];
141
142    // test if the bus should be considered occupied for the current
143    // port
144    if (!layer.tryTiming(src_port)) {
145        DPRINTF(NoncoherentBus, "recvTimingResp: src %s %s 0x%x BUSY\n",
146                src_port->name(), pkt->cmdString(), pkt->getAddr());
147        return false;
148    }
149
150    DPRINTF(NoncoherentBus, "recvTimingResp: src %s %s 0x%x\n",
151            src_port->name(), pkt->cmdString(), pkt->getAddr());
152
153    calcPacketTiming(pkt);
154    Tick packetFinishTime = pkt->finishTime;
155
156    // send the packet to the destination through one of our slave
157    // ports, as determined by the destination field
158    bool success M5_VAR_USED = slavePorts[pkt->getDest()]->sendTimingResp(pkt);
159
160    // currently it is illegal to block responses... can lead to
161    // deadlock
162    assert(success);
163
164    layer.succeededTiming(packetFinishTime);
165
166    return true;
167}
168
169void
170NoncoherentBus::recvRetry()
171{
172    // only one layer that can deal with it
173    layer.recvRetry();
174}
175
176Tick
177NoncoherentBus::recvAtomic(PacketPtr pkt, PortID slave_port_id)
178{
179    DPRINTF(NoncoherentBus, "recvAtomic: packet src %s addr 0x%x cmd %s\n",
180            slavePorts[slave_port_id]->name(), pkt->getAddr(),
181            pkt->cmdString());
182
183    // determine the destination port
184    PortID dest_id = findPort(pkt->getAddr());
185
186    // forward the request to the appropriate destination
187    Tick response_latency = masterPorts[dest_id]->sendAtomic(pkt);
188
189    pkt->finishTime = curTick() + response_latency;
190    return response_latency;
191}
192
193void
194NoncoherentBus::recvFunctional(PacketPtr pkt, PortID slave_port_id)
195{
196    if (!pkt->isPrint()) {
197        // don't do DPRINTFs on PrintReq as it clutters up the output
198        DPRINTF(NoncoherentBus,
199                "recvFunctional: packet src %s addr 0x%x cmd %s\n",
200                slavePorts[slave_port_id]->name(), pkt->getAddr(),
201                pkt->cmdString());
202    }
203
204    // determine the destination port
205    PortID dest_id = findPort(pkt->getAddr());
206
207    // forward the request to the appropriate destination
208    masterPorts[dest_id]->sendFunctional(pkt);
209}
210
211unsigned int
212NoncoherentBus::drain(Event *de)
213{
214    // only one layer to worry about at the moment
215    return layer.drain(de);
216}
217
218NoncoherentBus*
219NoncoherentBusParams::create()
220{
221    return new NoncoherentBus(this);
222}
223