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author | Akash Bagdia <akash.bagdia@arm.com> | 2014-09-20 17:18:23 -0400 |
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committer | Akash Bagdia <akash.bagdia@arm.com> | 2014-09-20 17:18:23 -0400 |
commit | 04e51e5e3e0d2c8af658e5ae29a240a0aac78f6e (patch) | |
tree | 009e17167757db81dad20a00ea469815ea0867bf /src/dev/arm/energy_ctrl.cc | |
parent | 4422d1322a8ed47bc9d743894ad47d82f33eba7c (diff) | |
download | gem5-04e51e5e3e0d2c8af658e5ae29a240a0aac78f6e.tar.xz |
energy: Memory-mapped Energy Controller component
This patch provides an Energy Controller device that provides software
(driver) access to a DVFS handler. The device is currently residing in
the dev/arm tree, but there is nothing inherently ARM specific in the
behaviour. It is currently only tested and supported for ARM Linux,
hence the location.
Diffstat (limited to 'src/dev/arm/energy_ctrl.cc')
-rw-r--r-- | src/dev/arm/energy_ctrl.cc | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/src/dev/arm/energy_ctrl.cc b/src/dev/arm/energy_ctrl.cc new file mode 100644 index 000000000..cbfa5aa79 --- /dev/null +++ b/src/dev/arm/energy_ctrl.cc @@ -0,0 +1,264 @@ +/* + * Copyright (c) 2012-2014 ARM Limited + * All rights reserved + * + * The license below extends only to copyright in the software and shall + * not be construed as granting a license to any other intellectual + * property including but not limited to intellectual property relating + * to a hardware implementation of the functionality of the software + * licensed hereunder. You may use the software subject to the license + * terms below provided that you ensure that this notice is replicated + * unmodified and in its entirety in all distributions of the software, + * modified or unmodified, in source code or in binary form. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * Authors: Vasileios Spiliopoulos + * Akash Bagdia + * Stephan Diestelhorst + */ + +#include "debug/EnergyCtrl.hh" +#include "dev/arm/energy_ctrl.hh" +#include "mem/packet.hh" +#include "mem/packet_access.hh" +#include "params/EnergyCtrl.hh" +#include "sim/dvfs_handler.hh" + +EnergyCtrl::EnergyCtrl(const Params *p) + : BasicPioDevice(p, PIO_NUM_FIELDS * 4), // each field is 32 bit + dvfsHandler(p->dvfs_handler), + domainID(0), + domainIDIndexToRead(0), + perfLevelAck(0), + perfLevelToRead(0), + updateAckEvent(this) +{ + fatal_if(!p->dvfs_handler, "EnergyCtrl: Needs a DVFSHandler for a " + "functioning system.\n"); +} + +Tick +EnergyCtrl::read(PacketPtr pkt) +{ + assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize); + assert(pkt->getSize() == 4); + pkt->allocate(); + + Addr daddr = pkt->getAddr() - pioAddr; + assert((daddr & 3) == 0); + Registers reg = Registers(daddr / 4); + + if (!dvfsHandler->isEnabled()) { + // NB: Zero is a good response if the handler is disabled + pkt->set<uint32_t>(0); + warn_once("EnergyCtrl: Disabled handler, ignoring read from reg %i\n", + reg); + DPRINTF(EnergyCtrl, "dvfs handler disabled, return 0 for read from "\ + "reg %i\n", reg); + pkt->makeAtomicResponse(); + return pioDelay; + } + + uint32_t result = 0; + Tick period; + double voltage; + + switch(reg) { + case DVFS_HANDLER_STATUS: + result = 1; + DPRINTF(EnergyCtrl, "dvfs handler enabled\n"); + break; + case DVFS_NUM_DOMAINS: + result = dvfsHandler->numDomains(); + DPRINTF(EnergyCtrl, "reading number of domains %d\n", result); + break; + case DVFS_DOMAINID_AT_INDEX: + result = dvfsHandler->domainID(domainIDIndexToRead); + DPRINTF(EnergyCtrl, "reading domain id at index %d as %d\n", + domainIDIndexToRead, result); + break; + case DVFS_HANDLER_TRANS_LATENCY: + // Return transition latency in nanoseconds + result = dvfsHandler->transLatency() / SimClock::Int::ns; + DPRINTF(EnergyCtrl, "reading dvfs handler trans latency %d ns\n", + result); + break; + case DOMAIN_ID: + result = domainID; + DPRINTF(EnergyCtrl, "reading domain id:%d\n", result); + break; + case PERF_LEVEL: + result = dvfsHandler->perfLevel(domainID); + DPRINTF(EnergyCtrl, "reading domain %d perf level: %d\n", + domainID, result); + break; + case PERF_LEVEL_ACK: + result = perfLevelAck; + DPRINTF(EnergyCtrl, "reading ack:%d\n", result); + // Signal is set for a single read only + if (result == 1) + perfLevelAck = 0; + break; + case NUM_OF_PERF_LEVELS: + result = dvfsHandler->numPerfLevels(domainID); + DPRINTF(EnergyCtrl, "reading num of perf level:%d\n", result); + break; + case FREQ_AT_PERF_LEVEL: + period = dvfsHandler->clkPeriodAtPerfLevel(domainID, perfLevelToRead); + result = ticksTokHz(period); + DPRINTF(EnergyCtrl, "reading freq %d KHz at perf level: %d\n", + result, perfLevelToRead); + break; + case VOLT_AT_PERF_LEVEL: + voltage = dvfsHandler->voltageAtPerfLevel(domainID, perfLevelToRead); + result = toMicroVolt(voltage); + DPRINTF(EnergyCtrl, "reading voltage %d u-volt at perf level: %d\n", + result, perfLevelToRead); + break; + default: + panic("Tried to read EnergyCtrl at offset %#x / reg %i\n", daddr, + reg); + } + pkt->set<uint32_t>(result); + pkt->makeAtomicResponse(); + return pioDelay; +} + +Tick +EnergyCtrl::write(PacketPtr pkt) +{ + assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize); + assert(pkt->getSize() == 4); + + uint32_t data; + data = pkt->get<uint32_t>(); + + Addr daddr = pkt->getAddr() - pioAddr; + assert((daddr & 3) == 0); + Registers reg = Registers(daddr / 4); + + if (!dvfsHandler->isEnabled()) { + // Ignore writes to a disabled controller + warn_once("EnergyCtrl: Disabled handler, ignoring write %u to "\ + "reg %i\n", data, reg); + DPRINTF(EnergyCtrl, "dvfs handler disabled, ignoring write %u to "\ + "reg %i\n", data, reg); + pkt->makeAtomicResponse(); + return pioDelay; + } + + switch(reg) { + case DVFS_DOMAINID_AT_INDEX: + domainIDIndexToRead = data; + DPRINTF(EnergyCtrl, "writing domain id index:%d\n", + domainIDIndexToRead); + break; + case DOMAIN_ID: + // Extra check to ensure that a valid domain ID is being queried + if (dvfsHandler->validDomainID(data)) { + domainID = data; + DPRINTF(EnergyCtrl, "writing domain id:%d\n", domainID); + } else { + DPRINTF(EnergyCtrl, "invalid domain id:%d\n", domainID); + } + break; + case PERF_LEVEL: + if (dvfsHandler->perfLevel(domainID, data)) { + if (updateAckEvent.scheduled()) { + // The OS driver is trying to change the perf level while + // another change is in flight. This is fine, but only a + // single acknowledgment will be sent. + DPRINTF(EnergyCtrl, "descheduling previous pending ack "\ + "event\n"); + deschedule(updateAckEvent); + } + schedule(updateAckEvent, curTick() + dvfsHandler->transLatency()); + DPRINTF(EnergyCtrl, "writing domain %d perf level: %d\n", + domainID, data); + } else { + DPRINTF(EnergyCtrl, "invalid / ineffective perf level:%d for "\ + "domain:%d\n", data, domainID); + } + break; + case PERF_LEVEL_TO_READ: + perfLevelToRead = data; + DPRINTF(EnergyCtrl, "writing perf level to read opp at: %d\n", + data); + break; + default: + panic("Tried to write EnergyCtrl at offset %#x\n", daddr); + break; + } + + pkt->makeAtomicResponse(); + return pioDelay; +} + +void +EnergyCtrl::serialize(std::ostream &os) +{ + SERIALIZE_SCALAR(domainID); + SERIALIZE_SCALAR(domainIDIndexToRead); + SERIALIZE_SCALAR(perfLevelToRead); + SERIALIZE_SCALAR(perfLevelAck); + + Tick next_event = updateAckEvent.scheduled() ? updateAckEvent.when() : 0; + SERIALIZE_SCALAR(next_event); +} + +void +EnergyCtrl::unserialize(Checkpoint *cp, const std::string §ion) +{ + UNSERIALIZE_SCALAR(domainID); + UNSERIALIZE_SCALAR(domainIDIndexToRead); + UNSERIALIZE_SCALAR(perfLevelToRead); + UNSERIALIZE_SCALAR(perfLevelAck); + Tick next_event = 0; + UNSERIALIZE_SCALAR(next_event); + + // restore scheduled events + if (next_event != 0) { + schedule(updateAckEvent, next_event); + } +} + +EnergyCtrl * EnergyCtrlParams::create() +{ + return new EnergyCtrl(this); +} + +void +EnergyCtrl::startup() +{ + if (!dvfsHandler->isEnabled()) { + warn("Existing EnergyCtrl, but no enabled DVFSHandler found.\n"); + } +} + +void +EnergyCtrl::init() +{ + BasicPioDevice::init(); +} |