1/*
2 * Copyright (c) 2013-2014, 2017 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 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions are
16 * met: redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer;
18 * redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution;
21 * neither the name of the copyright holders nor the names of its
22 * contributors may be used to endorse or promote products derived from
23 * this software without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 *
37 * Authors: Andrew Bardsley
38 */
39
40/**
41 * @file
42 *
43 *  Base classes for ClockedObjects which have evaluate functions to
44 *  look like clock ticking operations.  TickedObject attaches gem5's event
45 *  queue to Ticked to apply actual scheduling.
46 */
47
48#ifndef __SIM_TICKED_OBJECT_HH__
49#define __SIM_TICKED_OBJECT_HH__
50
51#include "sim/clocked_object.hh"
52
53class TickedObjectParams;
54
55/** Ticked attaches gem5's event queue/scheduler to evaluate
56 *  calls and provides a start/stop interface to ticking.
57 *
58 *  Ticked is not a ClockedObject but can be attached to one by
59 *  inheritance and by calling regStats, serialize/unserialize */
60class Ticked : public Serializable
61{
62  protected:
63    /** ClockedObject who is responsible for this Ticked's actions/stats */
64    ClockedObject &object;
65
66    /** The wrapper for processClockEvent */
67    EventFunctionWrapper event;
68
69    /** Evaluate and reschedule */
70    void processClockEvent();
71
72    /** Have I been started? and am not stopped */
73    bool running;
74
75    /** Time of last stop event to calculate run time */
76    Cycles lastStopped;
77
78  private:
79    /** Locally allocated stats */
80    Stats::Scalar *numCyclesLocal;
81
82  protected:
83    /** Total number of cycles either ticked or spend stopped */
84    Stats::Scalar &numCycles;
85
86    /** Number of cycles ticked */
87    Stats::Scalar tickCycles;
88
89    /** Number of cycles stopped */
90    Stats::Formula idleCycles;
91
92  public:
93    Ticked(ClockedObject &object_,
94        Stats::Scalar *imported_num_cycles = NULL,
95        Event::Priority priority = Event::CPU_Tick_Pri);
96
97    virtual ~Ticked() { }
98
99    /** Register {num,ticks}Cycles if necessary.  If numCycles is
100     *  imported, be sure to register it *before* calling this regStats */
101    void regStats();
102
103    /** Start ticking */
104    void
105    start()
106    {
107        if (!running) {
108            if (!event.scheduled())
109                object.schedule(event, object.clockEdge(Cycles(1)));
110            running = true;
111            numCycles += cyclesSinceLastStopped();
112            countCycles(cyclesSinceLastStopped());
113        }
114    }
115
116    /** How long have we been stopped for? */
117    Cycles
118    cyclesSinceLastStopped() const
119    {
120        return object.curCycle() - lastStopped;
121    }
122
123    /** Reset stopped time to current time */
124    void
125    resetLastStopped()
126    {
127        lastStopped = object.curCycle();
128    }
129
130    /** Cancel the next tick event and issue no more */
131    void
132    stop()
133    {
134        if (running) {
135            if (event.scheduled())
136                object.deschedule(event);
137            running = false;
138            resetLastStopped();
139        }
140    }
141
142    /** Checkpoint lastStopped */
143    void serialize(CheckpointOut &cp) const override;
144    void unserialize(CheckpointIn &cp) override;
145
146    /** Action to call on the clock tick */
147    virtual void evaluate() = 0;
148
149    /**
150     * Callback to handle cycle statistics and probes.
151     *
152     * This callback is called at the beginning of a new cycle active
153     * cycle and when restarting the ticked object. The delta
154     * parameter indicates the number of cycles elapsed since the
155     * previous call is normally '1' unless the object has been
156     * stopped and restarted.
157     *
158     * @param delta Number of cycles since the previous call.
159     */
160    virtual void countCycles(Cycles delta) {}
161};
162
163/** TickedObject attaches Ticked to ClockedObject and can be used as
164 *  a base class where ticked operation */
165class TickedObject : public ClockedObject, public Ticked
166{
167  public:
168    TickedObject(const TickedObjectParams *params,
169        Event::Priority priority = Event::CPU_Tick_Pri);
170
171    /** Disambiguate to make these functions overload correctly */
172    using ClockedObject::regStats;
173    using ClockedObject::serialize;
174    using ClockedObject::unserialize;
175
176    /** Pass on regStats, serialize etc. onto Ticked */
177    void regStats() override;
178    void serialize(CheckpointOut &cp) const override;
179    void unserialize(CheckpointIn &cp) override;
180};
181
182#endif /* __SIM_TICKED_OBJECT_HH__ */
183