energy_ctrl.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 *          Stephan Diestelhorst
40 */
41
42#include "debug/EnergyCtrl.hh"
43#include "dev/arm/energy_ctrl.hh"
44#include "mem/packet.hh"
45#include "mem/packet_access.hh"
46#include "params/EnergyCtrl.hh"
47#include "sim/dvfs_handler.hh"
48
49EnergyCtrl::EnergyCtrl(const Params *p)
50    : BasicPioDevice(p, PIO_NUM_FIELDS * 4),        // each field is 32 bit
51      dvfsHandler(p->dvfs_handler),
52      domainID(0),
53      domainIDIndexToRead(0),
54      perfLevelAck(0),
55      perfLevelToRead(0),
56      updateAckEvent(this)
57{
58    fatal_if(!p->dvfs_handler, "EnergyCtrl: Needs a DVFSHandler for a "
59             "functioning system.\n");
60}
61
62Tick
63EnergyCtrl::read(PacketPtr pkt)
64{
65    assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
66    assert(pkt->getSize() == 4);
67
68    Addr daddr = pkt->getAddr() - pioAddr;
69    assert((daddr & 3) == 0);
70    Registers reg = Registers(daddr / 4);
71
72    if (!dvfsHandler->isEnabled()) {
73        // NB: Zero is a good response if the handler is disabled
74        pkt->set<uint32_t>(0);
75        warn_once("EnergyCtrl: Disabled handler, ignoring read from reg %i\n",
76                  reg);
77        DPRINTF(EnergyCtrl, "dvfs handler disabled, return 0 for read from "\
78                "reg %i\n", reg);
79        pkt->makeAtomicResponse();
80        return pioDelay;
81    }
82
83    uint32_t result = 0;
84    Tick period;
85    double voltage;
86
87    switch(reg) {
88      case DVFS_HANDLER_STATUS:
89        result = 1;
90        DPRINTF(EnergyCtrl, "dvfs handler enabled\n");
91        break;
92      case DVFS_NUM_DOMAINS:
93        result = dvfsHandler->numDomains();
94        DPRINTF(EnergyCtrl, "reading number of domains %d\n", result);
95        break;
96      case DVFS_DOMAINID_AT_INDEX:
97        result = dvfsHandler->domainID(domainIDIndexToRead);
98        DPRINTF(EnergyCtrl, "reading domain id at index %d as %d\n",
99                domainIDIndexToRead, result);
100        break;
101      case DVFS_HANDLER_TRANS_LATENCY:
102        // Return transition latency in nanoseconds
103        result = dvfsHandler->transLatency() / SimClock::Int::ns;
104        DPRINTF(EnergyCtrl, "reading dvfs handler trans latency %d ns\n",
105                result);
106        break;
107      case DOMAIN_ID:
108        result = domainID;
109        DPRINTF(EnergyCtrl, "reading domain id:%d\n", result);
110        break;
111      case PERF_LEVEL:
112        result = dvfsHandler->perfLevel(domainID);
113        DPRINTF(EnergyCtrl, "reading domain %d perf level: %d\n",
114                domainID, result);
115        break;
116      case PERF_LEVEL_ACK:
117        result = perfLevelAck;
118        DPRINTF(EnergyCtrl, "reading ack:%d\n", result);
119        // Signal is set for a single read only
120        if (result == 1)
121            perfLevelAck = 0;
122        break;
123      case NUM_OF_PERF_LEVELS:
124        result = dvfsHandler->numPerfLevels(domainID);
125        DPRINTF(EnergyCtrl, "reading num of perf level:%d\n", result);
126        break;
127      case FREQ_AT_PERF_LEVEL:
128        period = dvfsHandler->clkPeriodAtPerfLevel(domainID, perfLevelToRead);
129        result = ticksTokHz(period);
130        DPRINTF(EnergyCtrl, "reading freq %d KHz at perf level: %d\n",
131                result, perfLevelToRead);
132        break;
133      case VOLT_AT_PERF_LEVEL:
134        voltage = dvfsHandler->voltageAtPerfLevel(domainID, perfLevelToRead);
135        result = toMicroVolt(voltage);
136        DPRINTF(EnergyCtrl, "reading voltage %d u-volt at perf level: %d\n",
137                result, perfLevelToRead);
138        break;
139      default:
140        panic("Tried to read EnergyCtrl at offset %#x / reg %i\n", daddr,
141              reg);
142    }
143    pkt->set<uint32_t>(result);
144    pkt->makeAtomicResponse();
145    return pioDelay;
146}
147
148Tick
149EnergyCtrl::write(PacketPtr pkt)
150{
151    assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
152    assert(pkt->getSize() == 4);
153
154    uint32_t data;
155    data = pkt->get<uint32_t>();
156
157    Addr daddr = pkt->getAddr() - pioAddr;
158    assert((daddr & 3) == 0);
159    Registers reg = Registers(daddr / 4);
160
161    if (!dvfsHandler->isEnabled()) {
162        // Ignore writes to a disabled controller
163        warn_once("EnergyCtrl: Disabled handler, ignoring write %u to "\
164                  "reg %i\n", data, reg);
165        DPRINTF(EnergyCtrl, "dvfs handler disabled, ignoring write %u to "\
166                "reg %i\n", data, reg);
167        pkt->makeAtomicResponse();
168        return pioDelay;
169    }
170
171    switch(reg) {
172      case DVFS_DOMAINID_AT_INDEX:
173        domainIDIndexToRead = data;
174        DPRINTF(EnergyCtrl, "writing domain id index:%d\n",
175                domainIDIndexToRead);
176        break;
177      case DOMAIN_ID:
178        // Extra check to ensure that a valid domain ID is being queried
179        if (dvfsHandler->validDomainID(data)) {
180            domainID = data;
181            DPRINTF(EnergyCtrl, "writing domain id:%d\n", domainID);
182        } else {
183           DPRINTF(EnergyCtrl, "invalid domain id:%d\n", domainID);
184        }
185        break;
186      case PERF_LEVEL:
187        if (dvfsHandler->perfLevel(domainID, data)) {
188            if (updateAckEvent.scheduled()) {
189                // The OS driver is trying to change the perf level while
190                // another change is in flight.  This is fine, but only a
191                // single acknowledgment will be sent.
192                DPRINTF(EnergyCtrl, "descheduling previous pending ack "\
193                        "event\n");
194                deschedule(updateAckEvent);
195            }
196            schedule(updateAckEvent, curTick() + dvfsHandler->transLatency());
197            DPRINTF(EnergyCtrl, "writing domain %d perf level: %d\n",
198                    domainID, data);
199        } else {
200            DPRINTF(EnergyCtrl, "invalid / ineffective perf level:%d for "\
201                    "domain:%d\n", data, domainID);
202        }
203        break;
204      case PERF_LEVEL_TO_READ:
205        perfLevelToRead = data;
206        DPRINTF(EnergyCtrl, "writing perf level to read opp at: %d\n",
207                data);
208        break;
209      default:
210        panic("Tried to write EnergyCtrl at offset %#x\n", daddr);
211        break;
212    }
213
214    pkt->makeAtomicResponse();
215    return pioDelay;
216}
217
218void
219EnergyCtrl::serialize(CheckpointOut &cp) const
220{
221    SERIALIZE_SCALAR(domainID);
222    SERIALIZE_SCALAR(domainIDIndexToRead);
223    SERIALIZE_SCALAR(perfLevelToRead);
224    SERIALIZE_SCALAR(perfLevelAck);
225
226    Tick next_event = updateAckEvent.scheduled() ? updateAckEvent.when() : 0;
227    SERIALIZE_SCALAR(next_event);
228}
229
230void
231EnergyCtrl::unserialize(CheckpointIn &cp)
232{
233    UNSERIALIZE_SCALAR(domainID);
234    UNSERIALIZE_SCALAR(domainIDIndexToRead);
235    UNSERIALIZE_SCALAR(perfLevelToRead);
236    UNSERIALIZE_SCALAR(perfLevelAck);
237    Tick next_event = 0;
238    UNSERIALIZE_SCALAR(next_event);
239
240    // restore scheduled events
241    if (next_event != 0) {
242        schedule(updateAckEvent, next_event);
243    }
244}
245
246EnergyCtrl * EnergyCtrlParams::create()
247{
248    return new EnergyCtrl(this);
249}
250
251void
252EnergyCtrl::startup()
253{
254    if (!dvfsHandler->isEnabled()) {
255        warn("Existing EnergyCtrl, but no enabled DVFSHandler found.\n");
256    }
257}
258
259void
260EnergyCtrl::init()
261{
262    BasicPioDevice::init();
263}
264