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 * Andreas Hansson
41 * Christopher Torng
42 */
43
44#include "debug/ClockDomain.hh"
45#include "params/ClockDomain.hh"
46#include "params/DerivedClockDomain.hh"
47#include "params/SrcClockDomain.hh"
48#include "sim/clock_domain.hh"
49#include "sim/voltage_domain.hh"
50#include "sim/clocked_object.hh"
51
52void
53ClockDomain::regStats()
54{
55 using namespace Stats;
56
57 // Expose the current clock period as a stat for observability in
58 // the dumps
59 currentClock
60 .scalar(_clockPeriod)
61 .name(params()->name + ".clock")
62 .desc("Clock period in ticks")
63 ;
64}
65
66double
67ClockDomain::voltage() const
68{
69 return _voltageDomain->voltage();
70}
71
72SrcClockDomain::SrcClockDomain(const Params *p) :
73 ClockDomain(p, p->voltage_domain)
74{
75 clockPeriod(p->clock);
76}
77
78void
79SrcClockDomain::clockPeriod(Tick clock_period)
80{
81 if (clock_period == 0) {
82 fatal("%s has a clock period of zero\n", name());
83 }
84
85 // Align all members to the current tick
86 for (auto m = members.begin(); m != members.end(); ++m) {
87 (*m)->updateClockPeriod();
88 }
89
90 _clockPeriod = clock_period;
91
92 DPRINTF(ClockDomain,
93 "Setting clock period to %d ticks for source clock %s\n",
94 _clockPeriod, name());
95
96 // inform any derived clocks they need to updated their period
97 for (auto c = children.begin(); c != children.end(); ++c) {
98 (*c)->updateClockPeriod();
99 }
100}
101
102SrcClockDomain *
103SrcClockDomainParams::create()
104{
105 return new SrcClockDomain(this);
106}
107
108DerivedClockDomain::DerivedClockDomain(const Params *p) :
109 ClockDomain(p, p->clk_domain->voltageDomain()),
110 parent(*p->clk_domain),
111 clockDivider(p->clk_divider)
112{
113 // Ensure that clock divider setting works as frequency divider and never
114 // work as frequency multiplier
115 if (clockDivider < 1) {
116 fatal("Clock divider param cannot be less than 1");
117 }
118
119 // let the parent keep track of this derived domain so that it can
120 // propagate changes
121 parent.addDerivedDomain(this);
122
123 // update our clock period based on the parents clock
124 updateClockPeriod();
125}
126
127void
128DerivedClockDomain::updateClockPeriod()
129{
130 // Align all members to the current tick
131 for (auto m = members.begin(); m != members.end(); ++m) {
132 (*m)->updateClockPeriod();
133 }
134
135 // recalculate the clock period, relying on the fact that changes
136 // propagate downwards in the tree
137 _clockPeriod = parent.clockPeriod() * clockDivider;
138
139 DPRINTF(ClockDomain,
140 "Setting clock period to %d ticks for derived clock %s\n",
141 _clockPeriod, name());
142
143 // inform any derived clocks
144 for (auto c = children.begin(); c != children.end(); ++c) {
145 (*c)->updateClockPeriod();
146 }
147}
148
149DerivedClockDomain *
150DerivedClockDomainParams::create()
151{
152 return new DerivedClockDomain(this);
153}