xbar.cc revision 2665 
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/**
32 * @file Definition of a bus object.
33 */
34
35
36#include "base/trace.hh"
37#include "mem/bus.hh"
38#include "sim/builder.hh"
39
40Port *
41Bus::getPort(const std::string &if_name)
42{
43    // if_name ignored?  forced to be empty?
44    int id = interfaces.size();
45    BusPort *bp = new BusPort(csprintf("%s-p%d", name(), id), this, id);
46    interfaces.push_back(bp);
47    return bp;
48}
49
50/** Get the ranges of anyone that we are connected to. */
51void
52Bus::init()
53{
54    std::vector<Port*>::iterator intIter;
55    for (intIter = interfaces.begin(); intIter != interfaces.end(); intIter++)
56        (*intIter)->sendStatusChange(Port::RangeChange);
57}
58
59
60/** Function called by the port when the bus is receiving a Timing
61 * transaction.*/
62bool
63Bus::recvTiming(Packet *pkt)
64{
65    Port *port;
66    DPRINTF(Bus, "recvTiming: packet src %d dest %d addr 0x%x cmd %s\n",
67            pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
68
69    short dest = pkt->getDest();
70    if (dest == Packet::Broadcast) {
71        port = findPort(pkt->getAddr(), pkt->getSrc());
72    } else {
73        assert(dest >= 0 && dest < interfaces.size());
74        assert(dest != pkt->getSrc()); // catch infinite loops
75        port = interfaces[dest];
76    }
77    if (port->sendTiming(pkt))  {
78        // packet was successfully sent, just return true.
79        return true;
80    }
81
82    // packet not successfully sent
83    retryList.push_back(interfaces[pkt->getSrc()]);
84    return false;
85}
86
87void
88Bus::recvRetry(int id)
89{
90    // Go through all the elements on the list calling sendRetry on each
91    // This is not very efficient at all but it works. Ultimately we should end
92    // up with something that is more intelligent.
93    int initialSize = retryList.size();
94    int i;
95    Port *p;
96
97    for (i = 0; i < initialSize; i++) {
98        assert(retryList.size() > 0);
99        p = retryList.front();
100        retryList.pop_front();
101        p->sendRetry();
102    }
103}
104
105
106Port *
107Bus::findPort(Addr addr, int id)
108{
109    /* An interval tree would be a better way to do this. --ali. */
110    int dest_id = -1;
111    int i = 0;
112    bool found = false;
113
114    while (i < portList.size() && !found)
115    {
116        if (portList[i].range == addr) {
117            dest_id = portList[i].portId;
118            found = true;
119            DPRINTF(Bus, "  found addr 0x%llx on device %d\n", addr, dest_id);
120        }
121        i++;
122    }
123    if (dest_id == -1)
124        panic("Unable to find destination for addr: %llx", addr);
125
126    // we shouldn't be sending this back to where it came from
127    assert(dest_id != id);
128
129    return interfaces[dest_id];
130}
131
132/** Function called by the port when the bus is receiving a Atomic
133 * transaction.*/
134Tick
135Bus::recvAtomic(Packet *pkt)
136{
137    DPRINTF(Bus, "recvAtomic: packet src %d dest %d addr 0x%x cmd %s\n",
138            pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
139    assert(pkt->getDest() == Packet::Broadcast);
140    return findPort(pkt->getAddr(), pkt->getSrc())->sendAtomic(pkt);
141}
142
143/** Function called by the port when the bus is receiving a Functional
144 * transaction.*/
145void
146Bus::recvFunctional(Packet *pkt)
147{
148    DPRINTF(Bus, "recvFunctional: packet src %d dest %d addr 0x%x cmd %s\n",
149            pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
150    assert(pkt->getDest() == Packet::Broadcast);
151    findPort(pkt->getAddr(), pkt->getSrc())->sendFunctional(pkt);
152}
153
154/** Function called by the port when the bus is receiving a status change.*/
155void
156Bus::recvStatusChange(Port::Status status, int id)
157{
158    assert(status == Port::RangeChange &&
159           "The other statuses need to be implemented.");
160
161    DPRINTF(BusAddrRanges, "received RangeChange from device id %d\n", id);
162
163    assert(id < interfaces.size() && id >= 0);
164    int x;
165    Port *port = interfaces[id];
166    AddrRangeList ranges;
167    AddrRangeList snoops;
168    AddrRangeIter iter;
169    std::vector<DevMap>::iterator portIter;
170
171    // Clean out any previously existent ids
172    for (portIter = portList.begin(); portIter != portList.end(); ) {
173        if (portIter->portId == id)
174            portIter = portList.erase(portIter);
175        else
176            portIter++;
177    }
178
179    port->getPeerAddressRanges(ranges, snoops);
180
181    // not dealing with snooping yet either
182    assert(snoops.size() == 0);
183    for(iter = ranges.begin(); iter != ranges.end(); iter++) {
184        DevMap dm;
185        dm.portId = id;
186        dm.range = *iter;
187
188        DPRINTF(BusAddrRanges, "Adding range %llx - %llx for id %d\n",
189                dm.range.start, dm.range.end, id);
190        portList.push_back(dm);
191    }
192    DPRINTF(MMU, "port list has %d entries\n", portList.size());
193
194    // tell all our peers that our address range has changed.
195    // Don't tell the device that caused this change, it already knows
196    for (x = 0; x < interfaces.size(); x++)
197        if (x != id)
198            interfaces[x]->sendStatusChange(Port::RangeChange);
199}
200
201void
202Bus::addressRanges(AddrRangeList &resp, AddrRangeList &snoop, int id)
203{
204    std::vector<DevMap>::iterator portIter;
205
206    resp.clear();
207    snoop.clear();
208
209    DPRINTF(BusAddrRanges, "received address range request, returning:\n");
210    for (portIter = portList.begin(); portIter != portList.end(); portIter++) {
211        if (portIter->portId != id) {
212            resp.push_back(portIter->range);
213            DPRINTF(BusAddrRanges, "  -- %#llX : %#llX\n",
214                    portIter->range.start, portIter->range.end);
215        }
216    }
217}
218
219BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bus)
220
221    Param<int> bus_id;
222
223END_DECLARE_SIM_OBJECT_PARAMS(Bus)
224
225BEGIN_INIT_SIM_OBJECT_PARAMS(Bus)
226    INIT_PARAM(bus_id, "a globally unique bus id")
227END_INIT_SIM_OBJECT_PARAMS(Bus)
228
229CREATE_SIM_OBJECT(Bus)
230{
231    return new Bus(getInstanceName(), bus_id);
232}
233
234REGISTER_SIM_OBJECT("Bus", Bus)
235