1/*
2 * Copyright (c) 2013-2014 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 * Stephan Diestelhorst
40 */
41
42/**
43 * @file
44 * DVFSHandler and DomainConfig class declaration used for managing voltage
45 * and frequency scaling of the various DVFS domains in the system (with each
46 * domain having their independent domain configuration information)
47 */
48
49
50#ifndef __SIM_DVFS_HANDLER_HH__
51#define __SIM_DVFS_HANDLER_HH__
52
53#include <vector>
54
55#include "debug/DVFS.hh"
56#include "params/ClockDomain.hh"
57#include "params/DVFSHandler.hh"
58#include "params/VoltageDomain.hh"
59#include "sim/clock_domain.hh"
60#include "sim/eventq.hh"
61#include "sim/sim_object.hh"
62#include "sim/voltage_domain.hh"
63
62
64/**
65 * DVFS Handler class, maintains a list of all the domains it can handle.
66 * Each entry of that list is an object of the DomainConfig class, and the
67 * handler uses the methods provided by that class to get access to the
68 * configuration of each domain. The handler is responsible for setting/getting
69 * clock periods and voltages from clock/voltage domains.
70 * The handler acts the bridge between software configurable information
71 * for each domain as provided to the controller and the hardware
72 * implementation details for those domains.
73 */
74class DVFSHandler : public SimObject
75{
76 public:
77 typedef DVFSHandlerParams Params;
78 DVFSHandler(const Params *p);
79
80 typedef SrcClockDomain::DomainID DomainID;
81 typedef SrcClockDomain::PerfLevel PerfLevel;
82
83 /**
84 * Get the number of domains assigned to this DVFS handler.
85 * @return Number of domains
86 */
87 uint32_t numDomains() const { return domainIDList.size(); }
88
89 /**
90 * Get the n-th domain ID, from the domains managed by this handler.
91 * @return Domain ID
92 */
93 DomainID domainID(uint32_t index) const;
94
95 /**
96 * Check whether a domain ID is known to the handler or not.
97 * @param domain_id Domain ID to check
98 * @return Domain ID known to handler?
99 */
100 bool validDomainID(DomainID domain_id) const;
101
102 /**
103 * Get transition latency to switch between performance levels.
104 * @return Transition latency
105 */
106 Tick transLatency() const { return _transLatency; }
107
108 /**
109 * Set a new performance level for the specified domain. The actual update
110 * will be delayed by transLatency().
111 *
112 * @param domain_id Software visible ID of the domain to be configured
113 * @param perf_level Requested performance level (0 - fast, >0 slower)
114 * @return status whether the setting was successful
115 */
116 bool perfLevel(DomainID domain_id, PerfLevel perf_level);
117
118 /**
119 * Get the current performance level of a domain. While a change request is
120 * in-flight, will return the current (i.e. old, unmodified) value.
121 *
122 * @param domain_id Domain ID to query
123 * @return Current performance level of the specified domain
124 */
125 PerfLevel perfLevel(DomainID domain_id) const {
126 assert(isEnabled());
127 return findDomain(domain_id)->perfLevel();
128 }
129
130 /**
131 * Read the clock period of the specified domain at the specified
132 * performance level.
133 * @param domain_id Domain ID to query
134 * @param perf_level Performance level of interest
135 * @return Clock period in ticks for the requested performance level of
136 * the respective domain
137 */
138 Tick clkPeriodAtPerfLevel(DomainID domain_id, PerfLevel perf_level) const
139 {
140 return findDomain(domain_id)->clkPeriodAtPerfLevel(perf_level);
141 }
142
143 /**
144 * Read the voltage of the specified domain at the specified
145 * performance level.
146 * @param domain_id Domain ID to query
147 * @param perf_level Performance level of interest
148 * @return Voltage for the requested performance level of the respective
149 * domain
150 */
151 double voltageAtPerfLevel(DomainID domain_id, PerfLevel perf_level) const
152 {
153 return findDomain(domain_id)->voltageDomain()->voltage(perf_level);
154 }
155
156 /**
157 * Get the total number of available performance levels.
158 *
159 * @param domain_id Domain ID to query
160 * @return Number of performance levels that where configured for the
161 * respective domain
162 */
163 PerfLevel numPerfLevels(PerfLevel domain_id) const
164 {
165 return findDomain(domain_id)->numPerfLevels();
166 }
167
168 /**
169 * Check enable status of the DVFS handler, when the handler is disabled, no
170 * request should be sent to the handler.
171 * @return True, if the handler is enabled
172 */
173 bool isEnabled() const { return enableHandler; }
174
175 void serialize(std::ostream &os);
176 void unserialize(Checkpoint *cp, const std::string &section);
177
178 private:
179 typedef std::map<DomainID, SrcClockDomain*> Domains;
180 Domains domains;
181
182 /**
183 * List of IDs avaiable in the domain list
184 */
185 std::vector<DomainID> domainIDList;
186
187 /**
188 * Clock domain of the system the handler is instantiated.
189 */
190 SrcClockDomain* sysClkDomain;
191
192 /**
193 * Search for a domain based on the domain ID.
194 *
195 * @param domain_id Domain ID to search for
196 * @return Pointer to the source clock domain with matching ID.
197 */
198 SrcClockDomain *findDomain(DomainID domain_id) const {
199 auto it = domains.find(domain_id);
200 panic_if(it == domains.end(),
201 "DVFS: Could not find a domain for ID %d.\n",domain_id );
202 return domains.find(domain_id)->second;
203 }
204
205 /**
206 * Disabling the DVFS handler ensures that all the DVFS migration requests
207 * are ignored. Domains remain at their default frequency and voltage.
208 */
209 bool enableHandler;
210
211
212 /**
213 * This corresponds to the maximum transition latency associated with the
214 * hardware transitioning from a particular performance level to the other
215 */
216 const Tick _transLatency;
217
218
219
220 /**
221 * Update performance level event, encapsulates all the required information
222 * for a future call to change a domain's performance level.
223 */
224 struct UpdateEvent : public Event {
225 UpdateEvent() : Event(DVFS_Update_Pri), domainIDToSet(0),
226 perfLevelToSet(0) {}
227
228 /**
229 * Static pointer to the single DVFS hander for all the update events
230 */
231 static DVFSHandler *dvfsHandler;
232
233 /**
234 * ID of the domain that will be changed by the in-flight event
235 */
236 DomainID domainIDToSet;
237
238 /**
239 * Target performance level of the in-flight event
240 */
241 PerfLevel perfLevelToSet;
242
243 /**
244 * Updates the performance level by modifying the clock and the voltage
245 * of the associated clocked objects. Gets information from
246 * domainIDToSet and perfLevelToSet for easier calling through an
247 * event.
248 */
249 void updatePerfLevel();
250
251 void process() { updatePerfLevel(); }
252 };
253
254 typedef std::map<DomainID, UpdateEvent> UpdatePerfLevelEvents;
255 /**
256 * Map from domain IDs -> perf level update events, records in-flight change
257 * requests per domain ID.
258 */
259 UpdatePerfLevelEvents updatePerfLevelEvents;
260};
261
262#endif // __SIM_DVFS_HANDLER_HH__