2 * Copyright (c) 2011-2012 ARM Limited
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.
14 * Copyright (c) 2002-2005 The Regents of The University of Michigan
15 * All rights reserved.
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.
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.
40 * Authors: Ron Dreslinski
48 * Declaration of a coherent bus.
51 #ifndef __MEM_COHERENT_BUS_HH__
52 #define __MEM_COHERENT_BUS_HH__
55 #include "params/CoherentBus.hh"
58 * A coherent bus connects a number of (potentially) snooping masters
59 * and slaves, and routes the request and response packets based on
60 * the address, and also forwards all requests to the snoopers and
61 * deals with the snoop responses.
63 * The coherent bus can be used as a template for modelling QPI,
64 * HyperTransport, ACE and coherent OCP buses, and is typically used
65 * for the L1-to-L2 buses and as the main system interconnect.
67 class CoherentBus : public BaseBus
73 * Declare the three layers of this bus, one for requests, one
74 * for responses, and one for snoop responses
76 Layer<SlavePort> reqLayer;
77 Layer<MasterPort> respLayer;
78 Layer<SlavePort> snoopRespLayer;
81 * Declaration of the coherent bus slave port type, one will be
82 * instantiated for each of the master ports connecting to the
85 class CoherentBusSlavePort : public SlavePort
90 /** A reference to the bus to which this port belongs. */
95 CoherentBusSlavePort(const std::string &_name,
96 CoherentBus &_bus, PortID _id)
97 : SlavePort(_name, &_bus, _id), bus(_bus)
103 * When receiving a timing request, pass it to the bus.
105 virtual bool recvTimingReq(PacketPtr pkt)
106 { return bus.recvTimingReq(pkt, id); }
109 * When receiving a timing snoop response, pass it to the bus.
111 virtual bool recvTimingSnoopResp(PacketPtr pkt)
112 { return bus.recvTimingSnoopResp(pkt, id); }
115 * When receiving an atomic request, pass it to the bus.
117 virtual Tick recvAtomic(PacketPtr pkt)
118 { return bus.recvAtomic(pkt, id); }
121 * When receiving a functional request, pass it to the bus.
123 virtual void recvFunctional(PacketPtr pkt)
124 { bus.recvFunctional(pkt, id); }
127 * When receiving a retry, pass it to the bus.
129 virtual void recvRetry()
130 { panic("Bus slave ports always succeed and should never retry.\n"); }
133 * Return the union of all adress ranges seen by this bus.
135 virtual AddrRangeList getAddrRanges() const
136 { return bus.getAddrRanges(); }
139 * Get the maximum block size as seen by the bus.
141 virtual unsigned deviceBlockSize() const
142 { return bus.findBlockSize(); }
147 * Declaration of the coherent bus master port type, one will be
148 * instantiated for each of the slave interfaces connecting to the
151 class CoherentBusMasterPort : public MasterPort
154 /** A reference to the bus to which this port belongs. */
159 CoherentBusMasterPort(const std::string &_name,
160 CoherentBus &_bus, PortID _id)
161 : MasterPort(_name, &_bus, _id), bus(_bus)
167 * Determine if this port should be considered a snooper. For
168 * a coherent bus master port this is always true.
170 * @return a boolean that is true if this port is snooping
172 virtual bool isSnooping() const
176 * When receiving a timing response, pass it to the bus.
178 virtual bool recvTimingResp(PacketPtr pkt)
179 { return bus.recvTimingResp(pkt, id); }
182 * When receiving a timing snoop request, pass it to the bus.
184 virtual void recvTimingSnoopReq(PacketPtr pkt)
185 { return bus.recvTimingSnoopReq(pkt, id); }
188 * When receiving an atomic snoop request, pass it to the bus.
190 virtual Tick recvAtomicSnoop(PacketPtr pkt)
191 { return bus.recvAtomicSnoop(pkt, id); }
194 * When receiving a functional snoop request, pass it to the bus.
196 virtual void recvFunctionalSnoop(PacketPtr pkt)
197 { bus.recvFunctionalSnoop(pkt, id); }
199 /** When reciving a range change from the peer port (at id),
200 pass it to the bus. */
201 virtual void recvRangeChange()
202 { bus.recvRangeChange(id); }
204 /** When reciving a retry from the peer port (at id),
205 pass it to the bus. */
206 virtual void recvRetry()
209 // Ask the bus to ask everyone on the bus what their block size is and
210 // take the max of it. This might need to be changed a bit if we ever
211 // support multiple block sizes.
212 virtual unsigned deviceBlockSize() const
213 { return bus.findBlockSize(); }
217 std::vector<SlavePort*> snoopPorts;
220 * Store the outstanding requests so we can determine which ones
221 * we generated and which ones were merely forwarded. This is used
222 * in the coherent bus when coherency responses come back.
224 std::set<RequestPtr> outstandingReq;
226 /** Function called by the port when the bus is recieving a Timing
228 virtual bool recvTimingReq(PacketPtr pkt, PortID slave_port_id);
230 /** Function called by the port when the bus is recieving a Timing
232 virtual bool recvTimingResp(PacketPtr pkt, PortID master_port_id);
234 /** Function called by the port when the bus is recieving a timing
236 virtual void recvTimingSnoopReq(PacketPtr pkt, PortID master_port_id);
238 /** Function called by the port when the bus is recieving a timing
240 virtual bool recvTimingSnoopResp(PacketPtr pkt, PortID slave_port_id);
242 /** Timing function called by port when it is once again able to process
247 * Forward a timing packet to our snoopers, potentially excluding
248 * one of the connected coherent masters to avoid sending a packet
249 * back to where it came from.
251 * @param pkt Packet to forward
252 * @param exclude_slave_port_id Id of slave port to exclude
254 void forwardTiming(PacketPtr pkt, PortID exclude_slave_port_id);
256 /** Function called by the port when the bus is recieving a Atomic
258 Tick recvAtomic(PacketPtr pkt, PortID slave_port_id);
260 /** Function called by the port when the bus is recieving an
261 atomic snoop transaction.*/
262 Tick recvAtomicSnoop(PacketPtr pkt, PortID master_port_id);
265 * Forward an atomic packet to our snoopers, potentially excluding
266 * one of the connected coherent masters to avoid sending a packet
267 * back to where it came from.
269 * @param pkt Packet to forward
270 * @param exclude_slave_port_id Id of slave port to exclude
272 * @return a pair containing the snoop response and snoop latency
274 std::pair<MemCmd, Tick> forwardAtomic(PacketPtr pkt,
275 PortID exclude_slave_port_id);
277 /** Function called by the port when the bus is recieving a Functional
279 void recvFunctional(PacketPtr pkt, PortID slave_port_id);
281 /** Function called by the port when the bus is recieving a functional
283 void recvFunctionalSnoop(PacketPtr pkt, PortID master_port_id);
286 * Forward a functional packet to our snoopers, potentially
287 * excluding one of the connected coherent masters to avoid
288 * sending a packet back to where it came from.
290 * @param pkt Packet to forward
291 * @param exclude_slave_port_id Id of slave port to exclude
293 void forwardFunctional(PacketPtr pkt, PortID exclude_slave_port_id);
299 CoherentBus(const CoherentBusParams *p);
301 unsigned int drain(Event *de);
304 #endif //__MEM_COHERENT_BUS_HH__