voltage_domain.cc revision 10905:a6ca6831e775 
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 <algorithm>
42
43#include "base/statistics.hh"
44#include "debug/VoltageDomain.hh"
45#include "params/VoltageDomain.hh"
46#include "sim/sim_object.hh"
47#include "sim/voltage_domain.hh"
48
49VoltageDomain::VoltageDomain(const Params *p)
50    : SimObject(p), voltageOpPoints(p->voltage), _perfLevel(0)
51{
52    fatal_if(voltageOpPoints.empty(), "DVFS: Empty set of voltages for "\
53             "voltage domain %s\n", name());
54
55    // Voltages must be sorted in descending order.
56    fatal_if(!std::is_sorted(voltageOpPoints.begin(), voltageOpPoints.end(),
57             std::greater<Voltages::value_type>()), "DVFS: Voltage operation "\
58             "points not in descending order for voltage domain %s\n",
59             name());
60}
61
62void
63VoltageDomain::perfLevel(PerfLevel perf_level)
64{
65    chatty_assert(perf_level < voltageOpPoints.size(),
66                  "DVFS: Requested voltage ID %d is outside the known "\
67                  "range for domain %s.\n", perf_level, name());
68
69    if (perf_level == _perfLevel) {
70        // Silently ignore identical overwrites
71        return;
72    }
73
74    _perfLevel = perf_level;
75
76    DPRINTF(VoltageDomain, "Setting voltage to %.3fV idx: %d for domain %s\n",
77            voltage(), perf_level, name());
78}
79
80bool
81VoltageDomain::sanitiseVoltages()
82{
83    if (numVoltages() == 1)
84        return false;
85
86    // Find the highest requested performance level and update the voltage
87    // domain with it
88    PerfLevel perf_max = (PerfLevel)-1;
89    for (auto dit = srcClockChildren.begin(); dit != srcClockChildren.end(); ++dit) {
90        SrcClockDomain* d = *dit;
91        chatty_assert(d->voltageDomain() == this, "DVFS: Clock domain %s "\
92                      "(id: %d) should not be registered with voltage domain "\
93                      "%s\n", d->name(), d->domainID(), name());
94
95        PerfLevel perf = d->perfLevel();
96
97        DPRINTF(VoltageDomain, "DVFS: Clock domain %s (id: %d) requests perf "\
98                "level %d\n", d->name(), d->domainID(), perf);
99
100        // NOTE: Descending sort of performance levels: 0 - fast, 5 - slow
101        if (perf < perf_max) {
102            DPRINTF(VoltageDomain, "DVFS: Updating max perf level %d -> %d\n",
103                    perf_max, perf);
104            perf_max = perf;
105        }
106    }
107    DPRINTF(VoltageDomain, "DVFS: Setting perf level of voltage domain %s "\
108            "from %d to %d.\n", name(), perfLevel(), perf_max);
109
110    // Set the performance level
111    if (perf_max != perfLevel()) {
112        perfLevel(perf_max);
113        return true;
114    } else {
115        return false;
116    }
117}
118
119void
120VoltageDomain::startup() {
121    bool changed = sanitiseVoltages();
122    if (changed) {
123        warn("DVFS: Perf level for voltage domain %s adapted to "\
124             "requested perf levels from source clock domains.\n", name());
125    }
126}
127
128void
129VoltageDomain::regStats()
130{
131    currentVoltage
132        .method(this, &VoltageDomain::voltage)
133        .name(params()->name + ".voltage")
134        .desc("Voltage in Volts")
135        ;
136}
137
138VoltageDomain *
139VoltageDomainParams::create()
140{
141    return new VoltageDomain(this);
142}
143
144void
145VoltageDomain::serialize(CheckpointOut &cp) const
146{
147    SERIALIZE_SCALAR(_perfLevel);
148}
149
150void
151VoltageDomain::unserialize(CheckpointIn &cp)
152{
153    UNSERIALIZE_SCALAR(_perfLevel);
154    perfLevel(_perfLevel);
155}
156