1/*
2 * Copyright (c) 2013-2014 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 *          Stephan Diestelhorst
43 */
44
45#include "sim/clock_domain.hh"
46
47#include <algorithm>
48#include <functional>
49
50#include "base/trace.hh"
51#include "debug/ClockDomain.hh"
52#include "params/ClockDomain.hh"
53#include "params/DerivedClockDomain.hh"
54#include "params/SrcClockDomain.hh"
55#include "sim/clocked_object.hh"
56#include "sim/voltage_domain.hh"
57
58void
59ClockDomain::regStats()
60{
61    SimObject::regStats();
62
63    using namespace Stats;
64
65    // Expose the current clock period as a stat for observability in
66    // the dumps
67    currentClock
68        .scalar(_clockPeriod)
69        .name(params()->name + ".clock")
70        .desc("Clock period in ticks")
71        ;
72}
73
74double
75ClockDomain::voltage() const
76{
77    return _voltageDomain->voltage();
78}
79
80SrcClockDomain::SrcClockDomain(const Params *p) :
81    ClockDomain(p, p->voltage_domain),
82    freqOpPoints(p->clock),
83    _domainID(p->domain_id),
84    _perfLevel(p->init_perf_level)
85{
86    VoltageDomain *vdom = p->voltage_domain;
87
88    fatal_if(freqOpPoints.empty(), "DVFS: Empty set of frequencies for "\
89             "domain %d %s\n", _domainID, name());
90
91    fatal_if(!vdom, "DVFS: Empty voltage domain specified for "\
92             "domain %d %s\n", _domainID, name());
93
94    fatal_if((vdom->numVoltages() > 1) &&
95             (vdom->numVoltages() != freqOpPoints.size()),
96             "DVFS: Number of frequency and voltage scaling points do "\
97             "not match: %d:%d ID: %d %s.\n", vdom->numVoltages(),
98             freqOpPoints.size(), _domainID, name());
99
100    // Frequency (& voltage) points should be declared in descending order,
101    // NOTE: Frequency is inverted to ticks, so checking for ascending ticks
102    fatal_if(!std::is_sorted(freqOpPoints.begin(), freqOpPoints.end()),
103             "DVFS: Frequency operation points not in descending order for "\
104             "domain with ID %d\n", _domainID);
105
106    fatal_if(_perfLevel >= freqOpPoints.size(), "DVFS: Initial DVFS point %d "\
107             "is outside of list for Domain ID: %d\n", _perfLevel, _domainID);
108
109    clockPeriod(freqOpPoints[_perfLevel]);
110
111    vdom->registerSrcClockDom(this);
112}
113
114void
115SrcClockDomain::clockPeriod(Tick clock_period)
116{
117    if (clock_period == 0) {
118        fatal("%s has a clock period of zero\n", name());
119    }
120
121    // Align all members to the current tick
122    for (auto m = members.begin(); m != members.end(); ++m) {
123        (*m)->updateClockPeriod();
124    }
125
126    _clockPeriod = clock_period;
127
128    DPRINTF(ClockDomain,
129            "Setting clock period to %d ticks for source clock %s\n",
130            _clockPeriod, name());
131
132    // inform any derived clocks they need to updated their period
133    for (auto c = children.begin(); c != children.end(); ++c) {
134        (*c)->updateClockPeriod();
135    }
136}
137
138void
139SrcClockDomain::perfLevel(PerfLevel perf_level)
140{
141    assert(validPerfLevel(perf_level));
142
143    if (perf_level == _perfLevel) {
144        // Silently ignore identical overwrites
145        return;
146    }
147
148    DPRINTF(ClockDomain, "DVFS: Switching performance level of domain %s "\
149            "(id: %d) from  %d to %d\n", name(), domainID(), _perfLevel,
150            perf_level);
151
152    _perfLevel = perf_level;
153
154    signalPerfLevelUpdate();
155}
156
157void SrcClockDomain::signalPerfLevelUpdate()
158{
159    // Signal the voltage domain that we have changed our perf level so that the
160    // voltage domain can recompute its performance level
161    voltageDomain()->sanitiseVoltages();
162
163    // Integrated switching of the actual clock value, too
164    clockPeriod(clkPeriodAtPerfLevel());
165}
166
167void
168SrcClockDomain::serialize(CheckpointOut &cp) const
169{
170    SERIALIZE_SCALAR(_perfLevel);
171    ClockDomain::serialize(cp);
172}
173
174void
175SrcClockDomain::unserialize(CheckpointIn &cp)
176{
177    ClockDomain::unserialize(cp);
178    UNSERIALIZE_SCALAR(_perfLevel);
179}
180
181void
182SrcClockDomain::startup()
183{
184    // Perform proper clock update when all related components have been
185    // created (i.e. after unserialization / object creation)
186    signalPerfLevelUpdate();
187}
188
189SrcClockDomain *
190SrcClockDomainParams::create()
191{
192    return new SrcClockDomain(this);
193}
194
195DerivedClockDomain::DerivedClockDomain(const Params *p) :
196    ClockDomain(p, p->clk_domain->voltageDomain()),
197    parent(*p->clk_domain),
198    clockDivider(p->clk_divider)
199{
200    // Ensure that clock divider setting works as frequency divider and never
201    // work as frequency multiplier
202    if (clockDivider < 1) {
203       fatal("Clock divider param cannot be less than 1");
204    }
205
206    // let the parent keep track of this derived domain so that it can
207    // propagate changes
208    parent.addDerivedDomain(this);
209
210    // update our clock period based on the parents clock
211    updateClockPeriod();
212}
213
214void
215DerivedClockDomain::updateClockPeriod()
216{
217    // Align all members to the current tick
218    for (auto m = members.begin(); m != members.end(); ++m) {
219        (*m)->updateClockPeriod();
220    }
221
222    // recalculate the clock period, relying on the fact that changes
223    // propagate downwards in the tree
224    _clockPeriod = parent.clockPeriod() * clockDivider;
225
226    DPRINTF(ClockDomain,
227            "Setting clock period to %d ticks for derived clock %s\n",
228            _clockPeriod, name());
229
230    // inform any derived clocks
231    for (auto c = children.begin(); c != children.end(); ++c) {
232        (*c)->updateClockPeriod();
233    }
234}
235
236DerivedClockDomain *
237DerivedClockDomainParams::create()
238{
239    return new DerivedClockDomain(this);
240}
241