1/*
2 * Copyright (c) 2011-2013 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) 2006 The Regents of The University of Michigan
15 * Copyright (c) 2015 The University of Bologna
16 * All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions are
20 * met: redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer;
22 * redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution;
25 * neither the name of the copyright holders nor the names of its
26 * contributors may be used to endorse or promote products derived from
27 * this software without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Authors: Ali Saidi
42 * Steve Reinhardt
43 * Andreas Hansson
44 * Erfan Azarkhish
45 */
46
47/**
48 * @file
49 * Declaration of the SerialLink Class, modeling Hybrid-Memory-Cube's serial
50 * interface.
51 */
52
53#ifndef __MEM_SERIAL_LINK_HH__
54#define __MEM_SERIAL_LINK_HH__
55
56#include <deque>
57
58#include "base/types.hh"
59#include "mem/mem_object.hh"
59#include "mem/port.hh"
60#include "params/SerialLink.hh"
61#include "sim/clocked_object.hh"
62
63/**
64 * SerialLink is a simple variation of the Bridge class, with the ability to
65 * account for the latency of packet serialization. We assume that the
66 * serializer component at the transmitter side does not need to receive the
67 * whole packet to start the serialization. But the deserializer waits for the
68 * complete packet to check its integrity first.
69 */
69class SerialLink : public MemObject
70class SerialLink : public ClockedObject
71{
72 protected:
73
74 /**
75 * A deferred packet stores a packet along with its scheduled
76 * transmission time
77 */
78 class DeferredPacket
79 {
80
81 public:
82
83 const Tick tick;
84 const PacketPtr pkt;
85
86 DeferredPacket(PacketPtr _pkt, Tick _tick) : tick(_tick), pkt(_pkt)
87 { }
88 };
89
90 // Forward declaration to allow the slave port to have a pointer
91 class SerialLinkMasterPort;
92
93 /**
94 * The port on the side that receives requests and sends
95 * responses. The slave port has a set of address ranges that it
96 * is responsible for. The slave port also has a buffer for the
97 * responses not yet sent.
98 */
99 class SerialLinkSlavePort : public SlavePort
100 {
101
102 private:
103
104 /** The serial_link to which this port belongs. */
105 SerialLink& serial_link;
106
107 /**
108 * Master port on the other side of the serial_link.
109 */
110 SerialLinkMasterPort& masterPort;
111
112 /** Minimum request delay though this serial_link. */
113 const Cycles delay;
114
115 /** Address ranges to pass through the serial_link */
116 const AddrRangeList ranges;
117
118 /**
119 * Response packet queue. Response packets are held in this
120 * queue for a specified delay to model the processing delay
121 * of the serial_link. We use a deque as we need to iterate over
122 * the items for functional accesses.
123 */
124 std::deque<DeferredPacket> transmitList;
125
126 /** Counter to track the outstanding responses. */
127 unsigned int outstandingResponses;
128
129 /** If we should send a retry when space becomes available. */
130 bool retryReq;
131
132 /** Max queue size for reserved responses. */
133 unsigned int respQueueLimit;
134
135 /**
136 * Is this side blocked from accepting new response packets.
137 *
138 * @return true if the reserved space has reached the set limit
139 */
140 bool respQueueFull() const;
141
142 /**
143 * Handle send event, scheduled when the packet at the head of
144 * the response queue is ready to transmit (for timing
145 * accesses only).
146 */
147 void trySendTiming();
148
149 /** Send event for the response queue. */
150 EventFunctionWrapper sendEvent;
151
152 public:
153
154 /**
155 * Constructor for the SerialLinkSlavePort.
156 *
157 * @param _name the port name including the owner
158 * @param _serial_link the structural owner
159 * @param _masterPort the master port on the other side of the
160 * serial_link
161 * @param _delay the delay in cycles from receiving to sending
162 * @param _resp_limit the size of the response queue
163 * @param _ranges a number of address ranges to forward
164 */
165 SerialLinkSlavePort(const std::string& _name, SerialLink&
166 _serial_link, SerialLinkMasterPort& _masterPort,
167 Cycles _delay, int _resp_limit, const
168 std::vector<AddrRange>& _ranges);
169
170 /**
171 * Queue a response packet to be sent out later and also schedule
172 * a send if necessary.
173 *
174 * @param pkt a response to send out after a delay
175 * @param when tick when response packet should be sent
176 */
177 void schedTimingResp(PacketPtr pkt, Tick when);
178
179 /**
180 * Retry any stalled request that we have failed to accept at
181 * an earlier point in time. This call will do nothing if no
182 * request is waiting.
183 */
184 void retryStalledReq();
185
186 protected:
187
188 /** When receiving a timing request from the peer port,
189 pass it to the serial_link. */
190 bool recvTimingReq(PacketPtr pkt);
191
192 /** When receiving a retry request from the peer port,
193 pass it to the serial_link. */
194 void recvRespRetry();
195
196 /** When receiving a Atomic requestfrom the peer port,
197 pass it to the serial_link. */
198 Tick recvAtomic(PacketPtr pkt);
199
200 /** When receiving a Functional request from the peer port,
201 pass it to the serial_link. */
202 void recvFunctional(PacketPtr pkt);
203
204 /** When receiving a address range request the peer port,
205 pass it to the serial_link. */
206 AddrRangeList getAddrRanges() const;
207 };
208
209
210 /**
211 * Port on the side that forwards requests and receives
212 * responses. The master port has a buffer for the requests not
213 * yet sent.
214 */
215 class SerialLinkMasterPort : public MasterPort
216 {
217
218 private:
219
220 /** The serial_link to which this port belongs. */
221 SerialLink& serial_link;
222
223 /**
224 * The slave port on the other side of the serial_link.
225 */
226 SerialLinkSlavePort& slavePort;
227
228 /** Minimum delay though this serial_link. */
229 const Cycles delay;
230
231 /**
232 * Request packet queue. Request packets are held in this
233 * queue for a specified delay to model the processing delay
234 * of the serial_link. We use a deque as we need to iterate over
235 * the items for functional accesses.
236 */
237 std::deque<DeferredPacket> transmitList;
238
239 /** Max queue size for request packets */
240 const unsigned int reqQueueLimit;
241
242 /**
243 * Handle send event, scheduled when the packet at the head of
244 * the outbound queue is ready to transmit (for timing
245 * accesses only).
246 */
247 void trySendTiming();
248
249 /** Send event for the request queue. */
250 EventFunctionWrapper sendEvent;
251
252 public:
253
254 /**
255 * Constructor for the SerialLinkMasterPort.
256 *
257 * @param _name the port name including the owner
258 * @param _serial_link the structural owner
259 * @param _slavePort the slave port on the other side of the
260 * serial_link
261 * @param _delay the delay in cycles from receiving to sending
262 * @param _req_limit the size of the request queue
263 */
264 SerialLinkMasterPort(const std::string& _name, SerialLink&
265 _serial_link, SerialLinkSlavePort& _slavePort, Cycles
266 _delay, int _req_limit);
267
268 /**
269 * Is this side blocked from accepting new request packets.
270 *
271 * @return true if the occupied space has reached the set limit
272 */
273 bool reqQueueFull() const;
274
275 /**
276 * Queue a request packet to be sent out later and also schedule
277 * a send if necessary.
278 *
279 * @param pkt a request to send out after a delay
280 * @param when tick when response packet should be sent
281 */
282 void schedTimingReq(PacketPtr pkt, Tick when);
283
284 /**
285 * Check a functional request against the packets in our
286 * request queue.
287 *
288 * @param pkt packet to check against
289 *
290 * @return true if we find a match
291 */
292 bool trySatisfyFunctional(PacketPtr pkt);
293
294 protected:
295
296 /** When receiving a timing request from the peer port,
297 pass it to the serial_link. */
298 bool recvTimingResp(PacketPtr pkt);
299
300 /** When receiving a retry request from the peer port,
301 pass it to the serial_link. */
302 void recvReqRetry();
303 };
304
305 /** Slave port of the serial_link. */
306 SerialLinkSlavePort slavePort;
307
308 /** Master port of the serial_link. */
309 SerialLinkMasterPort masterPort;
310
311 /** Number of parallel lanes in this serial link */
312 unsigned num_lanes;
313
314 /** Speed of each link (Gb/s) in this serial link */
315 uint64_t link_speed;
316
317 public:
318
319 Port &getPort(const std::string &if_name,
320 PortID idx=InvalidPortID);
321
322 virtual void init();
323
324 typedef SerialLinkParams Params;
325
326 SerialLink(SerialLinkParams *p);
327};
328
329#endif //__MEM_SERIAL_LINK_HH__