clock_domain.hh revision 9827:f47274776aa0 
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;
59class VoltageDomain;
60
61/**
62 * The ClockDomain provides clock to group of clocked objects bundled
63 * under the same clock domain. The clock domains, in turn, are
64 * grouped into voltage domains. The clock domains provide support for
65 * a hierarchial structure with source and derived domains.
66 */
67class ClockDomain : public SimObject
68{
69
70  protected:
71
72    /**
73     * Pre-computed clock period in ticks. This is populated by the
74     * inheriting classes based on how their period is determined.
75     */
76    Tick _clockPeriod;
77
78    /**
79     * Voltage domain this clock domain belongs to
80     */
81    VoltageDomain *_voltageDomain;
82
83    /**
84     * Pointers to potential derived clock domains so we can propagate
85     * changes.
86     */
87    std::vector<DerivedClockDomain*> children;
88
89  public:
90
91    typedef ClockDomainParams Params;
92    ClockDomain(const Params *p, VoltageDomain *voltage_domain) :
93        SimObject(p),
94        _clockPeriod(0),
95        _voltageDomain(voltage_domain) {}
96
97    /**
98     * Get the clock period.
99     *
100     * @return Clock period in ticks
101     */
102    inline Tick clockPeriod() const { return _clockPeriod; }
103
104    /**
105     * Get the voltage domain.
106     *
107     * @return Voltage domain this clock domain belongs to
108     */
109    inline VoltageDomain *voltageDomain() const { return _voltageDomain; }
110
111
112    /**
113     * Get the current voltage this clock domain operates at.
114     *
115     * @return Voltage applied to the clock domain
116     */
117    inline double voltage() const;
118
119    /**
120     * Add a derived domain.
121     *
122     * @param Derived domain to add as a child
123     */
124    void addDerivedDomain(DerivedClockDomain *clock_domain)
125    { children.push_back(clock_domain); }
126
127};
128
129/**
130 * The source clock domains provides the notion of a clock domain that is
131 * connected to a tunable clock source. It maintains the clock period and
132 * provides methods for setting/getting the clock.
133 */
134class SrcClockDomain : public ClockDomain
135{
136
137  public:
138
139    typedef SrcClockDomainParams Params;
140    SrcClockDomain(const Params *p);
141
142    /**
143     * Set new clock value
144     * @param clock The new clock period in ticks
145     */
146    void clockPeriod(Tick clock_period);
147
148};
149
150/**
151 * The derived clock domains provides the notion of a clock domain
152 * that is connected to a parent clock domain that can either be a
153 * source clock domain or a derived clock domain. It maintains the
154 * clock divider and provides methods for getting the clock.
155 */
156class DerivedClockDomain: public ClockDomain
157{
158
159  public:
160
161    typedef DerivedClockDomainParams Params;
162    DerivedClockDomain(const Params *p);
163
164    /**
165     * Called by the parent clock domain to propagate changes. This
166     * also involves propagating the change further to any children of
167     * the derived domain itself.
168     */
169    void updateClockPeriod();
170
171  private:
172
173    /**
174     * Reference to the parent clock domain this clock domain derives
175     * its clock period from
176     */
177    ClockDomain &parent;
178
179    /**
180     * Local clock divider of the domain
181     */
182    const uint64_t clockDivider;
183};
184
185#endif
186