1/*
2 * Copyright (c) 2013 ARM Limited
3 * Copyright (c) 2013 Cornell University
4 * All rights reserved
5 *
6 * The license below extends only to copyright in the software and shall
7 * not be construed as granting a license to any other intellectual
8 * property including but not limited to intellectual property relating
9 * to a hardware implementation of the functionality of the software
10 * licensed hereunder. You may use the software subject to the license
11 * terms below provided that you ensure that this notice is replicated
12 * unmodified and in its entirety in all distributions of the software,
13 * modified or unmodified, in source code or in binary form.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions are
17 * met: redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer;
19 * redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution;
22 * neither the name of the copyright holders nor the names of its
23 * contributors may be used to endorse or promote products derived from
24 * this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
27 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
28 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
29 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
30 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
31 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
32 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
36 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 *
38 * Authors: Vasileios Spiliopoulos
39 * Akash Bagdia
40 * Christopher Torng
41 */
42
43/**
44 * @file
45 * ClockDomain declarations.
46 */
47
48#ifndef __SIM_CLOCK_DOMAIN_HH__
49#define __SIM_CLOCK_DOMAIN_HH__
50
51#include <algorithm>
52
53#include "base/statistics.hh"
54#include "params/ClockDomain.hh"
55#include "params/DerivedClockDomain.hh"
56#include "params/SrcClockDomain.hh"
57#include "sim/sim_object.hh"
58
59/**
60 * Forward declaration
61 */
62class DerivedClockDomain;
63class VoltageDomain;
64class ClockedObject;
65
66/**
67 * The ClockDomain provides clock to group of clocked objects bundled
68 * under the same clock domain. The clock domains, in turn, are
69 * grouped into voltage domains. The clock domains provide support for
70 * a hierarchial structure with source and derived domains.
71 */
72class ClockDomain : public SimObject
73{
74
75 private:
76
77 /**
78 * Stat to report clock period of clock domain
79 */
80 Stats::Value currentClock;
81
82 protected:
83
84 /**
85 * Pre-computed clock period in ticks. This is populated by the
86 * inheriting classes based on how their period is determined.
87 */
88 Tick _clockPeriod;
89
90 /**
91 * Voltage domain this clock domain belongs to
92 */
93 VoltageDomain *_voltageDomain;
94
95 /**
96 * Pointers to potential derived clock domains so we can propagate
97 * changes.
98 */
99 std::vector<DerivedClockDomain*> children;
100
101 /**
102 * Pointers to members of this clock domain, so that when the clock
103 * period changes, we can update each member's tick.
104 */
105 std::vector<ClockedObject*> members;
106
107 public:
108
109 typedef ClockDomainParams Params;
110 ClockDomain(const Params *p, VoltageDomain *voltage_domain) :
111 SimObject(p),
112 _clockPeriod(0),
113 _voltageDomain(voltage_domain) {}
114
115 void regStats();
116
117 /**
118 * Get the clock period.
119 *
120 * @return Clock period in ticks
121 */
122 inline Tick clockPeriod() const { return _clockPeriod; }
123
124 /**
125 * Register a ClockedObject to this ClockDomain.
126 *
127 * @param ClockedObject to add as a member
128 */
129 void registerWithClockDomain(ClockedObject *c)
130 {
131 assert(c != NULL);
132 assert(std::find(members.begin(), members.end(), c) == members.end());
133 members.push_back(c);
134 }
135
136 /**
137 * Get the voltage domain.
138 *
139 * @return Voltage domain this clock domain belongs to
140 */
141 inline VoltageDomain *voltageDomain() const { return _voltageDomain; }
142
143
144 /**
145 * Get the current voltage this clock domain operates at.
146 *
147 * @return Voltage applied to the clock domain
148 */
149 inline double voltage() const;
150
151 /**
152 * Add a derived domain.
153 *
154 * @param Derived domain to add as a child
155 */
156 void addDerivedDomain(DerivedClockDomain *clock_domain)
157 { children.push_back(clock_domain); }
158
159};
160
161/**
162 * The source clock domains provides the notion of a clock domain that is
163 * connected to a tunable clock source. It maintains the clock period and
164 * provides methods for setting/getting the clock.
165 */
166class SrcClockDomain : public ClockDomain
167{
168
169 public:
170
171 typedef SrcClockDomainParams Params;
172 SrcClockDomain(const Params *p);
173
174 /**
175 * Set new clock value
176 * @param clock The new clock period in ticks
177 */
178 void clockPeriod(Tick clock_period);
179
180 // Explicitly import the otherwise hidden clockPeriod
181 using ClockDomain::clockPeriod;
182};
183
184/**
185 * The derived clock domains provides the notion of a clock domain
186 * that is connected to a parent clock domain that can either be a
187 * source clock domain or a derived clock domain. It maintains the
188 * clock divider and provides methods for getting the clock.
189 */
190class DerivedClockDomain: public ClockDomain
191{
192
193 public:
194
195 typedef DerivedClockDomainParams Params;
196 DerivedClockDomain(const Params *p);
197
198 /**
199 * Called by the parent clock domain to propagate changes. This
200 * also involves propagating the change further to any children of
201 * the derived domain itself.
202 */
203 void updateClockPeriod();
204
205 private:
206
207 /**
208 * Reference to the parent clock domain this clock domain derives
209 * its clock period from
210 */
211 ClockDomain &parent;
212
213 /**
214 * Local clock divider of the domain
215 */
216 const uint64_t clockDivider;
217};
218
219#endif