coherent_xbar.cc revision 2657 
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
29/**
30 * @file Definition of a bus object.
31 */
32
33
34#include "base/trace.hh"
35#include "mem/bus.hh"
36#include "sim/builder.hh"
37
38Port *
39Bus::getPort(const std::string &if_name)
40{
41    // if_name ignored?  forced to be empty?
42    int id = interfaces.size();
43    BusPort *bp = new BusPort(csprintf("%s-p%d", name(), id), this, id);
44    interfaces.push_back(bp);
45    return bp;
46}
47
48/** Get the ranges of anyone that we are connected to. */
49void
50Bus::init()
51{
52    std::vector<Port*>::iterator intIter;
53    for (intIter = interfaces.begin(); intIter != interfaces.end(); intIter++)
54        (*intIter)->sendStatusChange(Port::RangeChange);
55}
56
57
58/** Function called by the port when the bus is receiving a Timing
59 * transaction.*/
60bool
61Bus::recvTiming(Packet *pkt)
62{
63    Port *port;
64    DPRINTF(Bus, "recvTiming: packet src %d dest %d addr 0x%x cmd %s\n",
65            pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
66
67    short dest = pkt->getDest();
68    if (dest == Packet::Broadcast) {
69        port = findPort(pkt->getAddr(), pkt->getSrc());
70    } else {
71        assert(dest >= 0 && dest < interfaces.size());
72        assert(dest != pkt->getSrc()); // catch infinite loops
73        port = interfaces[dest];
74    }
75    if (port->sendTiming(pkt))  {
76        // packet was successfully sent, just return true.
77        return true;
78    }
79
80    // packet not successfully sent
81    retryList.push_back(interfaces[pkt->getSrc()]);
82    return false;
83}
84
85void
86Bus::recvRetry(int id)
87{
88    // Go through all the elements on the list calling sendRetry on each
89    // This is not very efficient at all but it works. Ultimately we should end
90    // up with something that is more intelligent.
91    int initialSize = retryList.size();
92    int i;
93    Port *p;
94
95    for (i = 0; i < initialSize; i++) {
96        assert(retryList.size() > 0);
97        p = retryList.front();
98        retryList.pop_front();
99        p->sendRetry();
100    }
101}
102
103
104Port *
105Bus::findPort(Addr addr, int id)
106{
107    /* An interval tree would be a better way to do this. --ali. */
108    int dest_id = -1;
109    int i = 0;
110    bool found = false;
111
112    while (i < portList.size() && !found)
113    {
114        if (portList[i].range == addr) {
115            dest_id = portList[i].portId;
116            found = true;
117            DPRINTF(Bus, "  found addr 0x%llx on device %d\n", addr, dest_id);
118        }
119        i++;
120    }
121    if (dest_id == -1)
122        panic("Unable to find destination for addr: %llx", addr);
123
124    // we shouldn't be sending this back to where it came from
125    assert(dest_id != id);
126
127    return interfaces[dest_id];
128}
129
130/** Function called by the port when the bus is receiving a Atomic
131 * transaction.*/
132Tick
133Bus::recvAtomic(Packet *pkt)
134{
135    DPRINTF(Bus, "recvAtomic: packet src %d dest %d addr 0x%x cmd %s\n",
136            pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
137    assert(pkt->getDest() == Packet::Broadcast);
138    return findPort(pkt->getAddr(), pkt->getSrc())->sendAtomic(pkt);
139}
140
141/** Function called by the port when the bus is receiving a Functional
142 * transaction.*/
143void
144Bus::recvFunctional(Packet *pkt)
145{
146    DPRINTF(Bus, "recvFunctional: packet src %d dest %d addr 0x%x cmd %s\n",
147            pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
148    assert(pkt->getDest() == Packet::Broadcast);
149    findPort(pkt->getAddr(), pkt->getSrc())->sendFunctional(pkt);
150}
151
152/** Function called by the port when the bus is receiving a status change.*/
153void
154Bus::recvStatusChange(Port::Status status, int id)
155{
156    assert(status == Port::RangeChange &&
157           "The other statuses need to be implemented.");
158
159    DPRINTF(BusAddrRanges, "received RangeChange from device id %d\n", id);
160
161    assert(id < interfaces.size() && id >= 0);
162    int x;
163    Port *port = interfaces[id];
164    AddrRangeList ranges;
165    AddrRangeList snoops;
166    AddrRangeIter iter;
167    std::vector<DevMap>::iterator portIter;
168
169    // Clean out any previously existent ids
170    for (portIter = portList.begin(); portIter != portList.end(); ) {
171        if (portIter->portId == id)
172            portIter = portList.erase(portIter);
173        else
174            portIter++;
175    }
176
177    port->getPeerAddressRanges(ranges, snoops);
178
179    // not dealing with snooping yet either
180    assert(snoops.size() == 0);
181    for(iter = ranges.begin(); iter != ranges.end(); iter++) {
182        DevMap dm;
183        dm.portId = id;
184        dm.range = *iter;
185
186        DPRINTF(BusAddrRanges, "Adding range %llx - %llx for id %d\n",
187                dm.range.start, dm.range.end, id);
188        portList.push_back(dm);
189    }
190    DPRINTF(MMU, "port list has %d entries\n", portList.size());
191
192    // tell all our peers that our address range has changed.
193    // Don't tell the device that caused this change, it already knows
194    for (x = 0; x < interfaces.size(); x++)
195        if (x != id)
196            interfaces[x]->sendStatusChange(Port::RangeChange);
197}
198
199void
200Bus::addressRanges(AddrRangeList &resp, AddrRangeList &snoop, int id)
201{
202    std::vector<DevMap>::iterator portIter;
203
204    resp.clear();
205    snoop.clear();
206
207    DPRINTF(BusAddrRanges, "received address range request, returning:\n");
208    for (portIter = portList.begin(); portIter != portList.end(); portIter++) {
209        if (portIter->portId != id) {
210            resp.push_back(portIter->range);
211            DPRINTF(BusAddrRanges, "  -- %#llX : %#llX\n",
212                    portIter->range.start, portIter->range.end);
213        }
214    }
215}
216
217BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bus)
218
219    Param<int> bus_id;
220
221END_DECLARE_SIM_OBJECT_PARAMS(Bus)
222
223BEGIN_INIT_SIM_OBJECT_PARAMS(Bus)
224    INIT_PARAM(bus_id, "a globally unique bus id")
225END_INIT_SIM_OBJECT_PARAMS(Bus)
226
227CREATE_SIM_OBJECT(Bus)
228{
229    return new Bus(getInstanceName(), bus_id);
230}
231
232REGISTER_SIM_OBJECT("Bus", Bus)
233