clock_domain.hh revision 9793 
1/*
2 * Copyright (c) 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 * 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: Vasileios Spiliopoulos
38 *          Akash Bagdia
39 */
40
41/**
42 * @file
43 * ClockDomain declarations.
44 */
45
46#ifndef __SIM_CLOCK_DOMAIN_HH__
47#define __SIM_CLOCK_DOMAIN_HH__
48
49#include "base/statistics.hh"
50#include "params/ClockDomain.hh"
51#include "params/DerivedClockDomain.hh"
52#include "params/SrcClockDomain.hh"
53#include "sim/sim_object.hh"
54
55/**
56 * Forward declaration
57 */
58class DerivedClockDomain;
59
60/**
61 * The ClockDomain provides clock to group of clocked objects bundled
62 * under the same clock domain. The clock domains provide support for
63 * a hierarchial structure with source and derived domains.
64 */
65class ClockDomain : public SimObject
66{
67
68  protected:
69
70    /**
71     * Pre-computed clock period in ticks. This is populated by the
72     * inheriting classes based on how their period is determined.
73     */
74    Tick _clockPeriod;
75
76    /**
77     * Pointers to potential derived clock domains so we can propagate
78     * changes.
79     */
80    std::vector<DerivedClockDomain*> children;
81
82  public:
83
84    typedef ClockDomainParams Params;
85    ClockDomain(const Params *p) : SimObject(p), _clockPeriod(0) {}
86
87    /**
88     * Get the clock period.
89     *
90     * @return Clock period in ticks
91     */
92    inline Tick clockPeriod() const { return _clockPeriod; }
93
94    /**
95     * Add a derived domain.
96     *
97     * @param Derived domain to add as a child
98     */
99    void addDerivedDomain(DerivedClockDomain *clock_domain)
100    { children.push_back(clock_domain); }
101
102};
103
104/**
105 * The source clock domains provides the notion of a clock domain that is
106 * connected to a tunable clock source. It maintains the clock period and
107 * provides methods for setting/getting the clock.
108 */
109class SrcClockDomain : public ClockDomain
110{
111
112  public:
113
114    typedef SrcClockDomainParams Params;
115    SrcClockDomain(const Params *p);
116
117    /**
118     * Set new clock value
119     * @param clock The new clock period in ticks
120     */
121    void clockPeriod(Tick clock_period);
122
123};
124
125/**
126 * The derived clock domains provides the notion of a clock domain
127 * that is connected to a parent clock domain that can either be a
128 * source clock domain or a derived clock domain. It maintains the
129 * clock divider and provides methods for getting the clock.
130 */
131class DerivedClockDomain: public ClockDomain
132{
133
134  public:
135
136    typedef DerivedClockDomainParams Params;
137    DerivedClockDomain(const Params *p);
138
139    /**
140     * Called by the parent clock domain to propagate changes. This
141     * also involves propagating the change further to any children of
142     * the derived domain itself.
143     */
144    void updateClockPeriod();
145
146  private:
147
148    /**
149     * Reference to the parent clock domain this clock domain derives
150     * its clock period from
151     */
152    ClockDomain &parent;
153
154    /**
155     * Local clock divider of the domain
156     */
157    const uint64_t clockDivider;
158};
159
160#endif
161