1/*
2 * Copyright (c) 2012 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#ifndef __SIM_VOLTAGE_DOMAIN_HH__
42#define __SIM_VOLTAGE_DOMAIN_HH__
43
44#include <vector>
45
46#include "base/statistics.hh"
47#include "params/VoltageDomain.hh"
48#include "sim/clock_domain.hh"
49#include "sim/sim_object.hh"
50
51/**
52 * A VoltageDomain is used to group clock domains that operate under
53 * the same voltage. The class provides methods for setting and
54 * getting the voltage.
55 */
56class VoltageDomain : public SimObject
57{
58  public:
59
60    typedef VoltageDomainParams Params;
61    VoltageDomain(const Params *p);
62
63    typedef SrcClockDomain::PerfLevel PerfLevel;
64
65    /**
66     * Get the current voltage.
67     *
68     * @return Voltage of the domain
69     */
70    double voltage() const { return voltageOpPoints[_perfLevel]; }
71
72    /**
73     * Get the voltage at specified performance level.
74     *
75     * @param perf_level Performance level for which the voltage is requested
76     * @return Voltage of the domain at specified performance level
77     */
78    double voltage(PerfLevel perf_level) const
79    {
80        chatty_assert(perf_level < numVoltages(), "VoltageDomain %s "\
81                      "request for voltage perf level %u is outside "\
82                      "of numVoltages %u", name(), perf_level,
83                      numVoltages());
84        return voltageOpPoints[perf_level];
85    }
86
87    uint32_t numVoltages() const { return (uint32_t)voltageOpPoints.size(); }
88
89    /**
90     * Set the voltage point of the domain.
91     * @param Voltage value to be set
92     */
93    void perfLevel(PerfLevel perf_level);
94
95    /**
96     * Get the voltage point of the domain.
97     * @param Voltage value to be set
98     */
99    PerfLevel perfLevel() const { return _perfLevel; }
100
101    /**
102     * Register a SrcClockDomain with this voltage domain.
103     * @param src_clock_domain The SrcClockDomain to register.
104     */
105    void registerSrcClockDom(SrcClockDomain *src_clock_dom) {
106        assert(src_clock_dom->voltageDomain() == this);
107        srcClockChildren.push_back(src_clock_dom);
108    }
109
110    /**
111     * Startup has all SrcClockDomains registered with this voltage domain, so
112     * try to make sure that all perf level requests from them are met.
113     */
114    void startup() override;
115
116    /**
117     * Recomputes the highest (fastest, i.e., numerically lowest) requested
118     * performance level of all associated clock domains, and updates the
119     * performance level of this voltage domain to match.  This means that for
120     * two connected clock domains, one fast and one slow, the voltage domain
121     * will provide the voltage associated with the fast DVFS operation point.
122     * Must be called whenever a clock domain decides to swtich its performance
123     * level.
124     *
125     * @return True, if the voltage was actually changed.
126     */
127    bool sanitiseVoltages();
128
129    void regStats() override;
130
131    void serialize(CheckpointOut &cp) const override;
132    void unserialize(CheckpointIn &cp) override;
133
134  private:
135    typedef std::vector<double> Voltages;
136    /**
137     * List of possible minimum voltage at each of the frequency operational
138     * points, should be in descending order and same size as freqOpPoints.
139     * An empty list corresponds to default voltage specified for the voltage
140     * domain its clock domain belongs. The same voltage is applied for each
141     * freqOpPoints, overall implying NO DVS
142     */
143    const Voltages voltageOpPoints;
144    PerfLevel _perfLevel;
145
146    /**
147     * Stat for reporting voltage of the domain
148     */
149    Stats::Value currentVoltage;
150
151    /**
152     * List of associated SrcClockDomains that are connected to this voltage
153     * domain.
154     */
155    typedef std::vector<SrcClockDomain *> SrcClockChildren;
156    SrcClockChildren srcClockChildren;
157};
158
159#endif
160