noncoherent_xbar.cc revision 10694:1a6785e37d81 
1/*
2 * Copyright (c) 2011-2014 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 non-coherent crossbar object.
48 */
49
50#include "base/misc.hh"
51#include "base/trace.hh"
52#include "debug/NoncoherentXBar.hh"
53#include "debug/XBar.hh"
54#include "mem/noncoherent_xbar.hh"
55
56NoncoherentXBar::NoncoherentXBar(const NoncoherentXBarParams *p)
57    : BaseXBar(p)
58{
59    // create the ports based on the size of the master and slave
60    // vector ports, and the presence of the default port, the ports
61    // are enumerated starting from zero
62    for (int i = 0; i < p->port_master_connection_count; ++i) {
63        std::string portName = csprintf("%s.master[%d]", name(), i);
64        MasterPort* bp = new NoncoherentXBarMasterPort(portName, *this, i);
65        masterPorts.push_back(bp);
66        reqLayers.push_back(new ReqLayer(*bp, *this,
67                                         csprintf(".reqLayer%d", i)));
68    }
69
70    // see if we have a default slave device connected and if so add
71    // our corresponding master port
72    if (p->port_default_connection_count) {
73        defaultPortID = masterPorts.size();
74        std::string portName = name() + ".default";
75        MasterPort* bp = new NoncoherentXBarMasterPort(portName, *this,
76                                                      defaultPortID);
77        masterPorts.push_back(bp);
78        reqLayers.push_back(new ReqLayer(*bp, *this, csprintf(".reqLayer%d",
79                                                              defaultPortID)));
80    }
81
82    // create the slave ports, once again starting at zero
83    for (int i = 0; i < p->port_slave_connection_count; ++i) {
84        std::string portName = csprintf("%s.slave[%d]", name(), i);
85        SlavePort* bp = new NoncoherentXBarSlavePort(portName, *this, i);
86        slavePorts.push_back(bp);
87        respLayers.push_back(new RespLayer(*bp, *this,
88                                           csprintf(".respLayer%d", i)));
89    }
90
91    clearPortCache();
92}
93
94NoncoherentXBar::~NoncoherentXBar()
95{
96    for (auto l: reqLayers)
97        delete l;
98    for (auto l: respLayers)
99        delete l;
100}
101
102bool
103NoncoherentXBar::recvTimingReq(PacketPtr pkt, PortID slave_port_id)
104{
105    // determine the source port based on the id
106    SlavePort *src_port = slavePorts[slave_port_id];
107
108    // we should never see express snoops on a non-coherent crossbar
109    assert(!pkt->isExpressSnoop());
110
111    // determine the destination based on the address
112    PortID master_port_id = findPort(pkt->getAddr());
113
114    // test if the layer should be considered occupied for the current
115    // port
116    if (!reqLayers[master_port_id]->tryTiming(src_port)) {
117        DPRINTF(NoncoherentXBar, "recvTimingReq: src %s %s 0x%x BUSY\n",
118                src_port->name(), pkt->cmdString(), pkt->getAddr());
119        return false;
120    }
121
122    DPRINTF(NoncoherentXBar, "recvTimingReq: src %s %s 0x%x\n",
123            src_port->name(), pkt->cmdString(), pkt->getAddr());
124
125    // store size and command as they might be modified when
126    // forwarding the packet
127    unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0;
128    unsigned int pkt_cmd = pkt->cmdToIndex();
129
130    calcPacketTiming(pkt);
131    Tick packetFinishTime = curTick() + pkt->payloadDelay;
132
133    // before forwarding the packet (and possibly altering it),
134    // remember if we are expecting a response
135    const bool expect_response = pkt->needsResponse() &&
136        !pkt->memInhibitAsserted();
137
138    // since it is a normal request, attempt to send the packet
139    bool success = masterPorts[master_port_id]->sendTimingReq(pkt);
140
141    if (!success)  {
142        // inhibited packets should never be forced to retry
143        assert(!pkt->memInhibitAsserted());
144
145        DPRINTF(NoncoherentXBar, "recvTimingReq: src %s %s 0x%x RETRY\n",
146                src_port->name(), pkt->cmdString(), pkt->getAddr());
147
148        // undo the calculation so we can check for 0 again
149        pkt->headerDelay = pkt->payloadDelay = 0;
150
151        // occupy until the header is sent
152        reqLayers[master_port_id]->failedTiming(src_port,
153                                                clockEdge(headerCycles));
154
155        return false;
156    }
157
158    // remember where to route the response to
159    if (expect_response) {
160        assert(routeTo.find(pkt->req) == routeTo.end());
161        routeTo[pkt->req] = slave_port_id;
162    }
163
164    reqLayers[master_port_id]->succeededTiming(packetFinishTime);
165
166    // stats updates
167    pktCount[slave_port_id][master_port_id]++;
168    pktSize[slave_port_id][master_port_id] += pkt_size;
169    transDist[pkt_cmd]++;
170
171    return true;
172}
173
174bool
175NoncoherentXBar::recvTimingResp(PacketPtr pkt, PortID master_port_id)
176{
177    // determine the source port based on the id
178    MasterPort *src_port = masterPorts[master_port_id];
179
180    // determine the destination
181    const auto route_lookup = routeTo.find(pkt->req);
182    assert(route_lookup != routeTo.end());
183    const PortID slave_port_id = route_lookup->second;
184    assert(slave_port_id != InvalidPortID);
185    assert(slave_port_id < respLayers.size());
186
187    // test if the layer should be considered occupied for the current
188    // port
189    if (!respLayers[slave_port_id]->tryTiming(src_port)) {
190        DPRINTF(NoncoherentXBar, "recvTimingResp: src %s %s 0x%x BUSY\n",
191                src_port->name(), pkt->cmdString(), pkt->getAddr());
192        return false;
193    }
194
195    DPRINTF(NoncoherentXBar, "recvTimingResp: src %s %s 0x%x\n",
196            src_port->name(), pkt->cmdString(), pkt->getAddr());
197
198    // store size and command as they might be modified when
199    // forwarding the packet
200    unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0;
201    unsigned int pkt_cmd = pkt->cmdToIndex();
202
203    calcPacketTiming(pkt);
204    Tick packetFinishTime = curTick() + pkt->payloadDelay;
205
206    // send the packet through the destination slave port
207    bool success M5_VAR_USED = slavePorts[slave_port_id]->sendTimingResp(pkt);
208
209    // currently it is illegal to block responses... can lead to
210    // deadlock
211    assert(success);
212
213    // remove the request from the routing table
214    routeTo.erase(route_lookup);
215
216    respLayers[slave_port_id]->succeededTiming(packetFinishTime);
217
218    // stats updates
219    pktCount[slave_port_id][master_port_id]++;
220    pktSize[slave_port_id][master_port_id] += pkt_size;
221    transDist[pkt_cmd]++;
222
223    return true;
224}
225
226void
227NoncoherentXBar::recvRetry(PortID master_port_id)
228{
229    // responses never block on forwarding them, so the retry will
230    // always be coming from a port to which we tried to forward a
231    // request
232    reqLayers[master_port_id]->recvRetry();
233}
234
235Tick
236NoncoherentXBar::recvAtomic(PacketPtr pkt, PortID slave_port_id)
237{
238    DPRINTF(NoncoherentXBar, "recvAtomic: packet src %s addr 0x%x cmd %s\n",
239            slavePorts[slave_port_id]->name(), pkt->getAddr(),
240            pkt->cmdString());
241
242    unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0;
243    unsigned int pkt_cmd = pkt->cmdToIndex();
244
245    // determine the destination port
246    PortID master_port_id = findPort(pkt->getAddr());
247
248    // stats updates for the request
249    pktCount[slave_port_id][master_port_id]++;
250    pktSize[slave_port_id][master_port_id] += pkt_size;
251    transDist[pkt_cmd]++;
252
253    // forward the request to the appropriate destination
254    Tick response_latency = masterPorts[master_port_id]->sendAtomic(pkt);
255
256    // add the response data
257    if (pkt->isResponse()) {
258        pkt_size = pkt->hasData() ? pkt->getSize() : 0;
259        pkt_cmd = pkt->cmdToIndex();
260
261        // stats updates
262        pktCount[slave_port_id][master_port_id]++;
263        pktSize[slave_port_id][master_port_id] += pkt_size;
264        transDist[pkt_cmd]++;
265    }
266
267    // @todo: Not setting first-word time
268    pkt->payloadDelay = response_latency;
269    return response_latency;
270}
271
272void
273NoncoherentXBar::recvFunctional(PacketPtr pkt, PortID slave_port_id)
274{
275    if (!pkt->isPrint()) {
276        // don't do DPRINTFs on PrintReq as it clutters up the output
277        DPRINTF(NoncoherentXBar,
278                "recvFunctional: packet src %s addr 0x%x cmd %s\n",
279                slavePorts[slave_port_id]->name(), pkt->getAddr(),
280                pkt->cmdString());
281    }
282
283    // determine the destination port
284    PortID dest_id = findPort(pkt->getAddr());
285
286    // forward the request to the appropriate destination
287    masterPorts[dest_id]->sendFunctional(pkt);
288}
289
290unsigned int
291NoncoherentXBar::drain(DrainManager *dm)
292{
293    // sum up the individual layers
294    unsigned int total = 0;
295    for (auto l: reqLayers)
296        total += l->drain(dm);
297    for (auto l: respLayers)
298        total += l->drain(dm);
299    return total;
300}
301
302NoncoherentXBar*
303NoncoherentXBarParams::create()
304{
305    return new NoncoherentXBar(this);
306}
307
308void
309NoncoherentXBar::regStats()
310{
311    // register the stats of the base class and our layers
312    BaseXBar::regStats();
313    for (auto l: reqLayers)
314        l->regStats();
315    for (auto l: respLayers)
316        l->regStats();
317}
318