From acd11787c9a650115efe13076f9d8d24b6332bd5 Mon Sep 17 00:00:00 2001 From: Adrian Herrera Date: Mon, 28 Oct 2019 20:28:51 +0000 Subject: [PATCH] dev-arm: GenericTimer, configurable base and low freqs Architecture states the system counter has a fixed base frequency provided in the first entry of the frequency modes table. Optionally, other lower frequencies may be specified in consecutive entries. This patch adds configurable frequencies to the GenericTimer model. The default base frequency is kept as the one that was previously hardcoded for backwards compatibility. The table is not recommended to be updated once the system is running. Change-Id: Icba0b340a0eb1cbb47dfe7d7e03b547af4570c60 Reviewed-by: Giacomo Travaglini Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22425 Maintainer: Giacomo Travaglini Tested-by: kokoro --- src/dev/arm/RealView.py | 8 ++++++++ src/dev/arm/generic_timer.cc | 23 ++++++++++++++++++----- src/dev/arm/generic_timer.hh | 8 +++++++- 3 files changed, 33 insertions(+), 6 deletions(-) diff --git a/src/dev/arm/RealView.py b/src/dev/arm/RealView.py index 6e8630a96..37cf72ede 100644 --- a/src/dev/arm/RealView.py +++ b/src/dev/arm/RealView.py @@ -404,6 +404,10 @@ class GenericTimer(ClockedObject): int_virt = Param.ArmPPI("Virtual timer interrupt") int_hyp = Param.ArmPPI("Hypervisor timer interrupt") + freqs = VectorParam.UInt32([0x01800000], "Frequencies available for the " + "system counter (in Hz). First element is the base frequency, " + "following are alternative lower ones which must be exact divisors") + def generateDeviceTree(self, state): node = FdtNode("timer") @@ -430,6 +434,10 @@ class GenericTimerMem(PioDevice): int_phys = Param.ArmSPI("Physical Interrupt") int_virt = Param.ArmSPI("Virtual Interrupt") + freqs = VectorParam.UInt32([0x01800000], "Frequencies available for the " + "system counter (in Hz). First element is the base frequency, " + "following are alternative lower ones which must be exact divisors") + class PL031(AmbaIntDevice): type = 'PL031' cxx_header = "dev/arm/rtc_pl031.hh" diff --git a/src/dev/arm/generic_timer.cc b/src/dev/arm/generic_timer.cc index 430b4ebfa..7c1f09add 100644 --- a/src/dev/arm/generic_timer.cc +++ b/src/dev/arm/generic_timer.cc @@ -1,5 +1,5 @@ /* - * Copyright (c) 2013, 2015, 2017-2018 ARM Limited + * Copyright (c) 2013, 2015, 2017-2018, 2019 ARM Limited * All rights reserved. * * The license below extends only to copyright in the software and shall @@ -36,6 +36,7 @@ * * Authors: Giacomo Gabrielli * Andreas Sandberg + * Adrian Herrera */ #include "dev/arm/generic_timer.hh" @@ -47,10 +48,21 @@ #include "params/GenericTimer.hh" #include "params/GenericTimerMem.hh" -SystemCounter::SystemCounter() - : _freq(0), _period(0), _resetTick(0), _regCntkctl(0) +SystemCounter::SystemCounter(std::vector &freqs) + : _freqTable(freqs), + _resetTick(0), + _regCntkctl(0) { - setFreq(0x01800000); + fatal_if(_freqTable.empty(), "SystemCounter::SystemCounter: Base " + "frequency not provided\n"); + // Store the table end marker as a 32-bit zero word + _freqTable.push_back(0); + fatal_if(_freqTable.size() > MAX_FREQ_ENTRIES, + "SystemCounter::SystemCounter: Architecture states a maximum of 1004 " + "frequency table entries, limit surpassed\n"); + // Set the active frequency to be the base + _freq = freqs.front(); + _period = (1.0 / _freq) * SimClock::Frequency; } void @@ -221,6 +233,7 @@ ArchTimer::drainResume() GenericTimer::GenericTimer(GenericTimerParams *p) : ClockedObject(p), + systemCounter(p->freqs), system(*p->system) { fatal_if(!p->system, "No system specified, can't instantiate timer.\n"); @@ -528,7 +541,7 @@ GenericTimerMem::GenericTimerMem(GenericTimerMemParams *p) timerRange(RangeSize(p->base + sys->getPageBytes(), sys->getPageBytes())), addrRanges{ctrlRange, timerRange}, - systemCounter(), + systemCounter(p->freqs), physTimer(csprintf("%s.phys_timer0", name()), *this, systemCounter, p->int_phys->get()), diff --git a/src/dev/arm/generic_timer.hh b/src/dev/arm/generic_timer.hh index 9a7f162e7..5e1965baf 100644 --- a/src/dev/arm/generic_timer.hh +++ b/src/dev/arm/generic_timer.hh @@ -36,6 +36,7 @@ * * Authors: Giacomo Gabrielli * Andreas Sandberg + * Adrian Herrera */ #ifndef __DEV_ARM_GENERIC_TIMER_HH__ @@ -64,6 +65,8 @@ class SystemCounter : public Serializable protected: /// Counter frequency (as specified by CNTFRQ). uint32_t _freq; + /// Frequency modes table with all possible frequencies for the counter + std::vector _freqTable; /// Cached copy of the counter period (inverse of the frequency). Tick _period; /// Tick when the counter was reset. @@ -74,8 +77,11 @@ class SystemCounter : public Serializable /// Hypervisor event stream control register uint32_t _regCnthctl; + /// Maximum architectural number of frequency table entries + static constexpr size_t MAX_FREQ_ENTRIES = 1004; + public: - SystemCounter(); + SystemCounter(std::vector &freqs); /// Returns the current value of the physical counter. uint64_t value() const -- 2.30.2