noncoherent_xbar.hh revision 10713 
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) 2002-2005 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: Ron Dreslinski
41 *          Ali Saidi
42 *          Andreas Hansson
43 *          William Wang
44 */
45
46/**
47 * @file
48 * Declaration of a non-coherent crossbar.
49 */
50
51#ifndef __MEM_NONCOHERENT_XBAR_HH__
52#define __MEM_NONCOHERENT_XBAR_HH__
53
54#include "mem/xbar.hh"
55#include "params/NoncoherentXBar.hh"
56
57/**
58 * A non-coherent crossbar connects a number of non-snooping masters
59 * and slaves, and routes the request and response packets based on
60 * the address. The request packets issued by the master connected to
61 * a non-coherent crossbar could still snoop in caches attached to a
62 * coherent crossbar, as is the case with the I/O bus and memory bus
63 * in most system configurations. No snoops will, however, reach any
64 * master on the non-coherent crossbar itself.
65 *
66 * The non-coherent crossbar can be used as a template for modelling
67 * PCIe, and non-coherent AMBA and OCP buses, and is typically used
68 * for the I/O buses.
69 */
70class NoncoherentXBar : public BaseXBar
71{
72
73  protected:
74
75    /**
76     * Declare the layers of this crossbar, one vector for requests
77     * and one for responses.
78     */
79    std::vector<ReqLayer*> reqLayers;
80    std::vector<RespLayer*> respLayers;
81
82    /**
83     * Declaration of the non-coherent crossbar slave port type, one
84     * will be instantiated for each of the master ports connecting to
85     * the crossbar.
86     */
87    class NoncoherentXBarSlavePort : public SlavePort
88    {
89      private:
90
91        /** A reference to the crossbar to which this port belongs. */
92        NoncoherentXBar &xbar;
93
94      public:
95
96        NoncoherentXBarSlavePort(const std::string &_name,
97                                NoncoherentXBar &_xbar, PortID _id)
98            : SlavePort(_name, &_xbar, _id), xbar(_xbar)
99        { }
100
101      protected:
102
103        /**
104         * When receiving a timing request, pass it to the crossbar.
105         */
106        virtual bool recvTimingReq(PacketPtr pkt)
107        { return xbar.recvTimingReq(pkt, id); }
108
109        /**
110         * When receiving an atomic request, pass it to the crossbar.
111         */
112        virtual Tick recvAtomic(PacketPtr pkt)
113        { return xbar.recvAtomic(pkt, id); }
114
115        /**
116         * When receiving a functional request, pass it to the crossbar.
117         */
118        virtual void recvFunctional(PacketPtr pkt)
119        { xbar.recvFunctional(pkt, id); }
120
121        /**
122         * When receiving a retry, pass it to the crossbar.
123         */
124        virtual void recvRespRetry()
125        { panic("Crossbar slave ports should never retry.\n"); }
126
127        /**
128         * Return the union of all adress ranges seen by this crossbar.
129         */
130        virtual AddrRangeList getAddrRanges() const
131        { return xbar.getAddrRanges(); }
132
133    };
134
135    /**
136     * Declaration of the crossbar master port type, one will be
137     * instantiated for each of the slave ports connecting to the
138     * crossbar.
139     */
140    class NoncoherentXBarMasterPort : public MasterPort
141    {
142      private:
143
144        /** A reference to the crossbar to which this port belongs. */
145        NoncoherentXBar &xbar;
146
147      public:
148
149        NoncoherentXBarMasterPort(const std::string &_name,
150                                 NoncoherentXBar &_xbar, PortID _id)
151            : MasterPort(_name, &_xbar, _id), xbar(_xbar)
152        { }
153
154      protected:
155
156        /**
157         * When receiving a timing response, pass it to the crossbar.
158         */
159        virtual bool recvTimingResp(PacketPtr pkt)
160        { return xbar.recvTimingResp(pkt, id); }
161
162        /** When reciving a range change from the peer port (at id),
163            pass it to the crossbar. */
164        virtual void recvRangeChange()
165        { xbar.recvRangeChange(id); }
166
167        /** When reciving a retry from the peer port (at id),
168            pass it to the crossbar. */
169        virtual void recvReqRetry()
170        { xbar.recvReqRetry(id); }
171
172    };
173
174    /** Function called by the port when the crossbar is recieving a Timing
175      request packet.*/
176    virtual bool recvTimingReq(PacketPtr pkt, PortID slave_port_id);
177
178    /** Function called by the port when the crossbar is recieving a Timing
179      response packet.*/
180    virtual bool recvTimingResp(PacketPtr pkt, PortID master_port_id);
181
182    /** Timing function called by port when it is once again able to process
183     * requests. */
184    void recvReqRetry(PortID master_port_id);
185
186    /** Function called by the port when the crossbar is recieving a Atomic
187      transaction.*/
188    Tick recvAtomic(PacketPtr pkt, PortID slave_port_id);
189
190    /** Function called by the port when the crossbar is recieving a Functional
191        transaction.*/
192    void recvFunctional(PacketPtr pkt, PortID slave_port_id);
193
194  public:
195
196    NoncoherentXBar(const NoncoherentXBarParams *p);
197
198    virtual ~NoncoherentXBar();
199
200    unsigned int drain(DrainManager *dm);
201
202    /**
203     * stats
204     */
205    virtual void regStats();
206    Stats::Scalar totPktSize;
207};
208
209#endif //__MEM_NONCOHERENT_XBAR_HH__
210