noncoherent_xbar.hh revision 10888:85a001f2193b 
1/*
2 * Copyright (c) 2011-2015 ARM Limited
3 * All rights reserved
4 *
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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 *
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18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
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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
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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
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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 QueuedSlavePort
88    {
89      private:
90
91        /** A reference to the crossbar to which this port belongs. */
92        NoncoherentXBar &xbar;
93
94        /** A normal packet queue used to store responses. */
95        RespPacketQueue queue;
96
97      public:
98
99        NoncoherentXBarSlavePort(const std::string &_name,
100                                NoncoherentXBar &_xbar, PortID _id)
101            : QueuedSlavePort(_name, &_xbar, queue, _id), xbar(_xbar),
102              queue(_xbar, *this)
103        { }
104
105      protected:
106
107        /**
108         * When receiving a timing request, pass it to the crossbar.
109         */
110        virtual bool recvTimingReq(PacketPtr pkt)
111        { return xbar.recvTimingReq(pkt, id); }
112
113        /**
114         * When receiving an atomic request, pass it to the crossbar.
115         */
116        virtual Tick recvAtomic(PacketPtr pkt)
117        { return xbar.recvAtomic(pkt, id); }
118
119        /**
120         * When receiving a functional request, pass it to the crossbar.
121         */
122        virtual void recvFunctional(PacketPtr pkt)
123        { xbar.recvFunctional(pkt, id); }
124
125        /**
126         * Return the union of all adress ranges seen by this crossbar.
127         */
128        virtual AddrRangeList getAddrRanges() const
129        { return xbar.getAddrRanges(); }
130
131    };
132
133    /**
134     * Declaration of the crossbar master port type, one will be
135     * instantiated for each of the slave ports connecting to the
136     * crossbar.
137     */
138    class NoncoherentXBarMasterPort : public MasterPort
139    {
140      private:
141
142        /** A reference to the crossbar to which this port belongs. */
143        NoncoherentXBar &xbar;
144
145      public:
146
147        NoncoherentXBarMasterPort(const std::string &_name,
148                                 NoncoherentXBar &_xbar, PortID _id)
149            : MasterPort(_name, &_xbar, _id), xbar(_xbar)
150        { }
151
152      protected:
153
154        /**
155         * When receiving a timing response, pass it to the crossbar.
156         */
157        virtual bool recvTimingResp(PacketPtr pkt)
158        { return xbar.recvTimingResp(pkt, id); }
159
160        /** When reciving a range change from the peer port (at id),
161            pass it to the crossbar. */
162        virtual void recvRangeChange()
163        { xbar.recvRangeChange(id); }
164
165        /** When reciving a retry from the peer port (at id),
166            pass it to the crossbar. */
167        virtual void recvReqRetry()
168        { xbar.recvReqRetry(id); }
169
170    };
171
172    /** Function called by the port when the crossbar is recieving a Timing
173      request packet.*/
174    virtual bool recvTimingReq(PacketPtr pkt, PortID slave_port_id);
175
176    /** Function called by the port when the crossbar is recieving a Timing
177      response packet.*/
178    virtual bool recvTimingResp(PacketPtr pkt, PortID master_port_id);
179
180    /** Timing function called by port when it is once again able to process
181     * requests. */
182    void recvReqRetry(PortID master_port_id);
183
184    /** Function called by the port when the crossbar is recieving a Atomic
185      transaction.*/
186    Tick recvAtomic(PacketPtr pkt, PortID slave_port_id);
187
188    /** Function called by the port when the crossbar is recieving a Functional
189        transaction.*/
190    void recvFunctional(PacketPtr pkt, PortID slave_port_id);
191
192  public:
193
194    NoncoherentXBar(const NoncoherentXBarParams *p);
195
196    virtual ~NoncoherentXBar();
197
198    unsigned int drain(DrainManager *dm);
199
200    /**
201     * stats
202     */
203    virtual void regStats();
204    Stats::Scalar totPktSize;
205};
206
207#endif //__MEM_NONCOHERENT_XBAR_HH__
208