noncoherent_xbar.hh revision 9083 
1/*
2 * Copyright (c) 2011-2012 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 bus.
49 */
50
51#ifndef __MEM_NONCOHERENT_BUS_HH__
52#define __MEM_NONCOHERENT_BUS_HH__
53
54#include "mem/bus.hh"
55#include "params/NoncoherentBus.hh"
56
57/**
58 * A non-coherent bus connects a number of non-snooping masters and
59 * slaves, and routes the request and response packets based on the
60 * address. The request packets issued by the master connected to a
61 * non-coherent bus could still snoop in caches attached to a coherent
62 * bus, as is the case with the I/O bus and memory bus in most system
63 * configurations. No snoops will, however, reach any master on the
64 * non-coherent bus itself.
65 *
66 * The non-coherent bus can be used as a template for modelling PCI,
67 * PCIe, and non-coherent AMBA and OCP buses, and is typically used
68 * for the I/O buses.
69 */
70class NoncoherentBus : public BaseBus
71{
72
73  protected:
74
75    /**
76     * Declaration of the non-coherent bus slave port type, one will
77     * be instantiated for each of the master ports connecting to the
78     * bus.
79     */
80    class NoncoherentBusSlavePort : public SlavePort
81    {
82      private:
83
84        /** A reference to the bus to which this port belongs. */
85        NoncoherentBus &bus;
86
87      public:
88
89        NoncoherentBusSlavePort(const std::string &_name,
90                                NoncoherentBus &_bus, PortID _id)
91            : SlavePort(_name, &_bus, _id), bus(_bus)
92        { }
93
94      protected:
95
96        /**
97         * When receiving a timing request, pass it to the bus.
98         */
99        virtual bool recvTimingReq(PacketPtr pkt)
100        { return bus.recvTimingReq(pkt, id); }
101
102        /**
103         * When receiving an atomic request, pass it to the bus.
104         */
105        virtual Tick recvAtomic(PacketPtr pkt)
106        { return bus.recvAtomic(pkt, id); }
107
108        /**
109         * When receiving a functional request, pass it to the bus.
110         */
111        virtual void recvFunctional(PacketPtr pkt)
112        { bus.recvFunctional(pkt, id); }
113
114        /**
115         * When receiving a retry, pass it to the bus.
116         */
117        virtual void recvRetry()
118        { panic("Bus slave ports always succeed and should never retry.\n"); }
119
120        /**
121         * Return the union of all adress ranges seen by this bus.
122         */
123        virtual AddrRangeList getAddrRanges()
124        { return bus.getAddrRanges(); }
125
126        /**
127         * Get the maximum block size as seen by the bus.
128         */
129        virtual unsigned deviceBlockSize() const
130        { return bus.findBlockSize(); }
131
132    };
133
134    /**
135     * Declaration of the bus master port type, one will be
136     * instantiated for each of the slave ports connecting to the
137     * bus.
138     */
139    class NoncoherentBusMasterPort : public MasterPort
140    {
141      private:
142
143        /** A reference to the bus to which this port belongs. */
144        NoncoherentBus &bus;
145
146      public:
147
148        NoncoherentBusMasterPort(const std::string &_name,
149                                 NoncoherentBus &_bus, PortID _id)
150            : MasterPort(_name, &_bus, _id), bus(_bus)
151        { }
152
153      protected:
154
155        /**
156         * When receiving a timing response, pass it to the bus.
157         */
158        virtual bool recvTimingResp(PacketPtr pkt)
159        { return bus.recvTimingResp(pkt, id); }
160
161        /** When reciving a range change from the peer port (at id),
162            pass it to the bus. */
163        virtual void recvRangeChange()
164        { bus.recvRangeChange(id); }
165
166        /** When reciving a retry from the peer port (at id),
167            pass it to the bus. */
168        virtual void recvRetry()
169        { bus.recvRetry(); }
170
171        /**
172         * Get the maximum block size as seen by the bus.
173         */
174        virtual unsigned deviceBlockSize() const
175        { return bus.findBlockSize(); }
176
177    };
178
179    /** Function called by the port when the bus is recieving a Timing
180      request packet.*/
181    virtual bool recvTimingReq(PacketPtr pkt, PortID slave_port_id);
182
183    /** Function called by the port when the bus is recieving a Timing
184      response packet.*/
185    virtual bool recvTimingResp(PacketPtr pkt, PortID master_port_id);
186
187    /** Function called by the port when the bus is recieving a Atomic
188      transaction.*/
189    Tick recvAtomic(PacketPtr pkt, PortID slave_port_id);
190
191    /** Function called by the port when the bus is recieving a Functional
192        transaction.*/
193    void recvFunctional(PacketPtr pkt, PortID slave_port_id);
194
195  public:
196
197    NoncoherentBus(const NoncoherentBusParams *p);
198
199};
200
201#endif //__MEM_NONCOHERENT_BUS_HH__
202