voltage_domain.cc revision 11793:ef606668d247 
1/*
2 * Copyright (c) 2012-2014 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#include "sim/voltage_domain.hh"
42
43#include <algorithm>
44
45#include "base/statistics.hh"
46#include "debug/VoltageDomain.hh"
47#include "params/VoltageDomain.hh"
48#include "sim/sim_object.hh"
49
50VoltageDomain::VoltageDomain(const Params *p)
51    : SimObject(p), voltageOpPoints(p->voltage), _perfLevel(0)
52{
53    fatal_if(voltageOpPoints.empty(), "DVFS: Empty set of voltages for "\
54             "voltage domain %s\n", name());
55
56    // Voltages must be sorted in descending order.
57    fatal_if(!std::is_sorted(voltageOpPoints.begin(), voltageOpPoints.end(),
58             std::greater<Voltages::value_type>()), "DVFS: Voltage operation "\
59             "points not in descending order for voltage domain %s\n",
60             name());
61}
62
63void
64VoltageDomain::perfLevel(PerfLevel perf_level)
65{
66    chatty_assert(perf_level < voltageOpPoints.size(),
67                  "DVFS: Requested voltage ID %d is outside the known "\
68                  "range for domain %s.\n", perf_level, name());
69
70    if (perf_level == _perfLevel) {
71        // Silently ignore identical overwrites
72        return;
73    }
74
75    _perfLevel = perf_level;
76
77    DPRINTF(VoltageDomain, "Setting voltage to %.3fV idx: %d for domain %s\n",
78            voltage(), perf_level, name());
79}
80
81bool
82VoltageDomain::sanitiseVoltages()
83{
84    if (numVoltages() == 1)
85        return false;
86
87    // Find the highest requested performance level and update the voltage
88    // domain with it
89    PerfLevel perf_max = (PerfLevel)-1;
90    for (auto dit = srcClockChildren.begin(); dit != srcClockChildren.end(); ++dit) {
91        SrcClockDomain* d = *dit;
92        chatty_assert(d->voltageDomain() == this, "DVFS: Clock domain %s "\
93                      "(id: %d) should not be registered with voltage domain "\
94                      "%s\n", d->name(), d->domainID(), name());
95
96        PerfLevel perf = d->perfLevel();
97
98        DPRINTF(VoltageDomain, "DVFS: Clock domain %s (id: %d) requests perf "\
99                "level %d\n", d->name(), d->domainID(), perf);
100
101        // NOTE: Descending sort of performance levels: 0 - fast, 5 - slow
102        if (perf < perf_max) {
103            DPRINTF(VoltageDomain, "DVFS: Updating max perf level %d -> %d\n",
104                    perf_max, perf);
105            perf_max = perf;
106        }
107    }
108    DPRINTF(VoltageDomain, "DVFS: Setting perf level of voltage domain %s "\
109            "from %d to %d.\n", name(), perfLevel(), perf_max);
110
111    // Set the performance level
112    if (perf_max != perfLevel()) {
113        perfLevel(perf_max);
114        return true;
115    } else {
116        return false;
117    }
118}
119
120void
121VoltageDomain::startup() {
122    bool changed = sanitiseVoltages();
123    if (changed) {
124        warn("DVFS: Perf level for voltage domain %s adapted to "\
125             "requested perf levels from source clock domains.\n", name());
126    }
127}
128
129void
130VoltageDomain::regStats()
131{
132    SimObject::regStats();
133
134    currentVoltage
135        .method(this, &VoltageDomain::voltage)
136        .name(params()->name + ".voltage")
137        .desc("Voltage in Volts")
138        ;
139}
140
141VoltageDomain *
142VoltageDomainParams::create()
143{
144    return new VoltageDomain(this);
145}
146
147void
148VoltageDomain::serialize(CheckpointOut &cp) const
149{
150    SERIALIZE_SCALAR(_perfLevel);
151}
152
153void
154VoltageDomain::unserialize(CheckpointIn &cp)
155{
156    UNSERIALIZE_SCALAR(_perfLevel);
157    perfLevel(_perfLevel);
158}
159