1/*
2 * Copyright (c) 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: Steve Reinhardt
41 */
42
43#ifndef __CPU_SIMPLE_TIMING_HH__
44#define __CPU_SIMPLE_TIMING_HH__
45
46#include "cpu/simple/base.hh"
47#include "cpu/translation.hh"
48#include "params/TimingSimpleCPU.hh"
49
50class TimingSimpleCPU : public BaseSimpleCPU
51{
52 public:
53
54 TimingSimpleCPU(TimingSimpleCPUParams * params);
55 virtual ~TimingSimpleCPU();
56
57 virtual void init();
58
59 private:
60
61 /*
62 * If an access needs to be broken into fragments, currently at most two,
63 * the the following two classes are used as the sender state of the
64 * packets so the CPU can keep track of everything. In the main packet
65 * sender state, there's an array with a spot for each fragment. If a
66 * fragment has already been accepted by the CPU, aka isn't waiting for
67 * a retry, it's pointer is NULL. After each fragment has successfully
68 * been processed, the "outstanding" counter is decremented. Once the
69 * count is zero, the entire larger access is complete.
70 */
71 class SplitMainSenderState : public Packet::SenderState
72 {
73 public:
74 int outstanding;
75 PacketPtr fragments[2];
76
77 int
78 getPendingFragment()
79 {
80 if (fragments[0]) {
81 return 0;
82 } else if (fragments[1]) {
83 return 1;
84 } else {
85 return -1;
86 }
87 }
88 };
89
90 class SplitFragmentSenderState : public Packet::SenderState
91 {
92 public:
93 SplitFragmentSenderState(PacketPtr _bigPkt, int _index) :
94 bigPkt(_bigPkt), index(_index)
95 {}
96 PacketPtr bigPkt;
97 int index;
98
99 void
100 clearFromParent()
101 {
102 SplitMainSenderState * main_send_state =
103 dynamic_cast<SplitMainSenderState *>(bigPkt->senderState);
104 main_send_state->fragments[index] = NULL;
105 }
106 };
107
108 class FetchTranslation : public BaseTLB::Translation
109 {
110 protected:
111 TimingSimpleCPU *cpu;
112
113 public:
114 FetchTranslation(TimingSimpleCPU *_cpu)
115 : cpu(_cpu)
116 {}
117
118 void
119 markDelayed()
120 {
121 assert(cpu->_status == BaseSimpleCPU::Running);
122 cpu->_status = ITBWaitResponse;
123 }
124
125 void
126 finish(Fault fault, RequestPtr req, ThreadContext *tc,
127 BaseTLB::Mode mode)
128 {
129 cpu->sendFetch(fault, req, tc);
130 }
131 };
132 FetchTranslation fetchTranslation;
133
134 void sendData(RequestPtr req, uint8_t *data, uint64_t *res, bool read);
135 void sendSplitData(RequestPtr req1, RequestPtr req2, RequestPtr req,
136 uint8_t *data, bool read);
137
138 void translationFault(Fault fault);
139
140 void buildPacket(PacketPtr &pkt, RequestPtr req, bool read);
141 void buildSplitPacket(PacketPtr &pkt1, PacketPtr &pkt2,
142 RequestPtr req1, RequestPtr req2, RequestPtr req,
143 uint8_t *data, bool read);
144
145 bool handleReadPacket(PacketPtr pkt);
146 // This function always implicitly uses dcache_pkt.
147 bool handleWritePacket();
148
149 /**
150 * A TimingCPUPort overrides the default behaviour of the
151 * recvTiming and recvRetry and implements events for the
152 * scheduling of handling of incoming packets in the following
153 * cycle.
154 */
155 class TimingCPUPort : public CpuPort
156 {
157 public:
158
159 TimingCPUPort(const std::string& _name, TimingSimpleCPU* _cpu)
160 : CpuPort(_name, _cpu), cpu(_cpu), retryEvent(this)
161 { }
162
163 protected:
164
165 /**
166 * Snooping a coherence request, do nothing.
167 */
168 virtual void recvTimingSnoopReq(PacketPtr pkt) { }
169
170 TimingSimpleCPU* cpu;
171
172 struct TickEvent : public Event
173 {
174 PacketPtr pkt;
175 TimingSimpleCPU *cpu;
176
177 TickEvent(TimingSimpleCPU *_cpu) : pkt(NULL), cpu(_cpu) {}
178 const char *description() const { return "Timing CPU tick"; }
179 void schedule(PacketPtr _pkt, Tick t);
180 };
181
182 EventWrapper<MasterPort, &MasterPort::sendRetry> retryEvent;
183 };
184
185 class IcachePort : public TimingCPUPort
186 {
187 public:
188
189 IcachePort(TimingSimpleCPU *_cpu)
190 : TimingCPUPort(_cpu->name() + ".icache_port", _cpu),
191 tickEvent(_cpu)
192 { }
193
194 protected:
195
196 virtual bool recvTimingResp(PacketPtr pkt);
197
198 virtual void recvRetry();
199
200 struct ITickEvent : public TickEvent
201 {
202
203 ITickEvent(TimingSimpleCPU *_cpu)
204 : TickEvent(_cpu) {}
205 void process();
206 const char *description() const { return "Timing CPU icache tick"; }
207 };
208
209 ITickEvent tickEvent;
210
211 };
212
213 class DcachePort : public TimingCPUPort
214 {
215 public:
216
217 DcachePort(TimingSimpleCPU *_cpu)
218 : TimingCPUPort(_cpu->name() + ".dcache_port", _cpu),
219 tickEvent(_cpu)
220 { }
221
222 protected:
223
224 virtual bool recvTimingResp(PacketPtr pkt);
225
226 virtual void recvRetry();
227
228 struct DTickEvent : public TickEvent
229 {
230 DTickEvent(TimingSimpleCPU *_cpu)
231 : TickEvent(_cpu) {}
232 void process();
233 const char *description() const { return "Timing CPU dcache tick"; }
234 };
235
236 DTickEvent tickEvent;
237
238 };
239
240 IcachePort icachePort;
241 DcachePort dcachePort;
242
243 PacketPtr ifetch_pkt;
244 PacketPtr dcache_pkt;
245
246 Tick previousCycle;
247
248 protected:
249
250 /** Return a reference to the data port. */
251 virtual CpuPort &getDataPort() { return dcachePort; }
252
253 /** Return a reference to the instruction port. */
254 virtual CpuPort &getInstPort() { return icachePort; }
255
256 public:
257
258 unsigned int drain(DrainManager *drain_manager);
259 void drainResume();
260
261 void switchOut();
262 void takeOverFrom(BaseCPU *oldCPU);
263
264 virtual void activateContext(ThreadID thread_num, Cycles delay);
265 virtual void suspendContext(ThreadID thread_num);
266
267 Fault readMem(Addr addr, uint8_t *data, unsigned size, unsigned flags);
268
269 Fault writeMem(uint8_t *data, unsigned size,
270 Addr addr, unsigned flags, uint64_t *res);
271
272 void fetch();
273 void sendFetch(Fault fault, RequestPtr req, ThreadContext *tc);
274 void completeIfetch(PacketPtr );
275 void completeDataAccess(PacketPtr pkt);
276 void advanceInst(Fault fault);
277
278 /** This function is used by the page table walker to determine if it could
279 * translate the a pending request or if the underlying request has been
280 * squashed. This always returns false for the simple timing CPU as it never
281 * executes any instructions speculatively.
282 * @ return Is the current instruction squashed?
283 */
284 bool isSquashed() const { return false; }
285
286 /**
287 * Print state of address in memory system via PrintReq (for
288 * debugging).
289 */
290 void printAddr(Addr a);
291
292 /**
293 * Finish a DTB translation.
294 * @param state The DTB translation state.
295 */
296 void finishTranslation(WholeTranslationState *state);
297
298 private:
299
300 typedef EventWrapper<TimingSimpleCPU, &TimingSimpleCPU::fetch> FetchEvent;
301 FetchEvent fetchEvent;
302
303 struct IprEvent : Event {
304 Packet *pkt;
305 TimingSimpleCPU *cpu;
306 IprEvent(Packet *_pkt, TimingSimpleCPU *_cpu, Tick t);
307 virtual void process();
308 virtual const char *description() const;
309 };
310
311 /**
312 * Check if a system is in a drained state.
313 *
314 * We need to drain if:
315 * <ul>
316 * <li>We are in the middle of a microcode sequence as some CPUs
317 * (e.g., HW accelerated CPUs) can't be started in the middle
318 * of a gem5 microcode sequence.
319 *
320 * <li>Stay at PC is true.
321 * </ul>
322 */
323 bool isDrained() {
324 return microPC() == 0 &&
325 !stayAtPC;
326 }
327
328 /**
329 * Try to complete a drain request.
330 *
331 * @returns true if the CPU is drained, false otherwise.
332 */
333 bool tryCompleteDrain();
334
335 /**
336 * Drain manager to use when signaling drain completion
337 *
338 * This pointer is non-NULL when draining and NULL otherwise.
339 */
340 DrainManager *drainManager;
341};
342
343#endif // __CPU_SIMPLE_TIMING_HH__