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energy: Memory-mapped Energy Controller component

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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.
This commit is contained in:
Akash Bagdia 2014-09-20 17:18:23 -04:00
parent 4422d1322a
commit 04e51e5e3e
4 changed files with 501 additions and 0 deletions
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47
src/dev/arm/EnergyCtrl.py Normal file
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# 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
from m5.params import *
from m5.SimObject import SimObject
from Device import BasicPioDevice
from m5.proxy import *
class EnergyCtrl(BasicPioDevice):
type = 'EnergyCtrl'
cxx_header = "dev/arm/energy_ctrl.hh"
dvfs_handler = Param.DVFSHandler(Parent.dvfs_handler, "DVFS handler")

3
src/dev/arm/SConscript
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@ -42,6 +42,7 @@ Import('*')
if env['TARGET_ISA'] == 'arm': if env['TARGET_ISA'] == 'arm':
SimObject('Gic.py') SimObject('Gic.py')
SimObject('RealView.py') SimObject('RealView.py')
SimObject('EnergyCtrl.py')
Source('a9scu.cc') Source('a9scu.cc')
Source('amba_device.cc') Source('amba_device.cc')
@ -59,6 +60,7 @@ if env['TARGET_ISA'] == 'arm':
Source('rtc_pl031.cc') Source('rtc_pl031.cc')
Source('timer_cpulocal.cc') Source('timer_cpulocal.cc')
Source('vgic.cc') Source('vgic.cc')
Source('energy_ctrl.cc')
DebugFlag('AMBA') DebugFlag('AMBA')
DebugFlag('HDLcd') DebugFlag('HDLcd')
@ -66,4 +68,5 @@ if env['TARGET_ISA'] == 'arm':
DebugFlag('Pl050') DebugFlag('Pl050')
DebugFlag('GIC') DebugFlag('GIC')
DebugFlag('RVCTRL') DebugFlag('RVCTRL')
DebugFlag('EnergyCtrl')
DebugFlag('VGIC') DebugFlag('VGIC')

264
src/dev/arm/energy_ctrl.cc Normal file
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/*
* 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 &section)
{
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();
}

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src/dev/arm/energy_ctrl.hh Normal file
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/*
* 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
*/
/**
* @file
* The energy controller is a device being used to manage power and energy
* related control operations within the system. It provides the necessary
* software interface to the kernel. The kernel will require gem5 specific
* drivers to access this device.
*
* Tasks handled by the controller are:
* a) Dynamic voltage and frequency scaling control operations
*
* Note that the registers defined do not resemble any specific controller
* device in real hardware. They are currently design to accomodate the gem5
* system requirements.
*/
#ifndef __DEV_ARM_ENERGY_CTRL_HH__
#define __DEV_ARM_ENERGY_CTRL_HH__
#include "dev/io_device.hh"
#include "params/EnergyCtrl.hh"
class DVFSHandler;
class EnergyCtrl : public BasicPioDevice
{
public:
/**
* Discovery flows:
* ----------------
* * get basic DVFS handler information
* read(DVFS_HANDLER_STATUS)
* read(DVFS_HANDLER_TRANS_LATENCY)
*
* * get the number of domain IDs
* read(DVFS_NUM_DOMAINS) -> domains
*
* * query the driver to get the IDs for all i in domains
* write(DVFS_DOMAINID_AT_INDEX <- i)
* read(DOMAIN_ID) -> domainID_i
*
* * for each domainID i get voltage / frequency pairs
* write(DOMAIN_ID <- domainID_i)
* read(NUM_OF_PERF_LEVELS) -> levels_i
* * for each l in levels_i
* write(PERF_LEVEL_TO_READ <- l)
* read(FREQ_AT_PERF_LEVEL) -> freq_l_i
* read(VOLT_AT_PERF_LEVEL) -> volt_l_i
*
*
* Setting a specific performance level (V/F combination)
* ------------------------------------------------------
* * get performance for domain_ID i
* write(DOMAIN_ID <- i)
* read(PERF_LEVEL) -> perf_level_i
*
* * set performance for domain_ID i
* write(DOMAIN_ID <- i)
* write(PERF_LEVEL <- perf_level_i)
* * wait for DVFS transition completion
* while (!read(PERF_LEVEL_ACK));
*/
enum Registers {
DVFS_HANDLER_STATUS = 0,
DVFS_NUM_DOMAINS,
DVFS_DOMAINID_AT_INDEX,
DVFS_HANDLER_TRANS_LATENCY,
DOMAIN_ID,
PERF_LEVEL,
PERF_LEVEL_ACK,
NUM_OF_PERF_LEVELS,
PERF_LEVEL_TO_READ,
FREQ_AT_PERF_LEVEL,
VOLT_AT_PERF_LEVEL,
PIO_NUM_FIELDS
};
typedef EnergyCtrlParams Params;
EnergyCtrl(const Params *p);
/**
* Read command sent to the device
* @param pkt Packet describing this request
* @return number of ticks it took to complete
*/
virtual Tick read(PacketPtr pkt);
/**
* Write command sent to the device
* @param pkt Packet describing this request
* @return number of ticks it took to complete
*/
virtual Tick write(PacketPtr pkt);
void serialize(std::ostream &os);
void unserialize(Checkpoint *cp, const std::string &section);
void startup();
void init();
private:
DVFSHandler *dvfsHandler;
/**
* Cluster ID (DOMAIN_ID) R/W register, programmed to ID of the domain for
* which the set/get performance level command can be issued
*/
uint32_t domainID;
/**
* Index for getting the domain ID from the domain ID list available with
* the DVFS handler
*/
uint32_t domainIDIndexToRead;
/**
* Acknowledgment (PERF_LEVEL_ACK) RO register, software polls this
* register to read back the status of the last programmed change in the
* domain ID and/or the performance level. Valid values are:
* '0' - Ack is not OK yet
* '1' - Ack is OK
* It is a read destructive register with a read of '1' resets the ack to
* '0'.
*/
uint32_t perfLevelAck;
uint32_t perfLevelToRead;
static uint32_t ticksTokHz(Tick period) {
return (uint32_t)(SimClock::Int::ms / period);
}
static uint32_t toMicroVolt(double voltage) {
return (uint32_t)(voltage * 1000000);
}
/**
* Update the acknowledgment that is read back by the software to confirm
* newly requested performance level has been set.
*/
void updatePLAck() {
perfLevelAck = 1;
}
EventWrapper<EnergyCtrl, &EnergyCtrl::updatePLAck> updateAckEvent;
};
#endif //__DEV_ARM_ENERGY_CTRL_HH__