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Date:   Fri, 26 Jul 2019 07:29:54 -0400
From:   Brian Masney <masneyb@onstation.org>
To:     Amit Kucheria <amit.kucheria@linaro.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Eduardo Valentin <edubezval@gmail.com>,
        Andy Gross <andy.gross@linaro.org>,
        Andy Gross <agross@kernel.org>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Rob Herring <robh+dt@kernel.org>,
        Zhang Rui <rui.zhang@intel.com>,
        Marc Gonzalez <marc.w.gonzalez@free.fr>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        Linux PM list <linux-pm@vger.kernel.org>
Subject: Re: [PATCH 00/15] thermal: qcom: tsens: Add interrupt support
Message-ID: <20190726112954.GA3984@onstation.org>
References: <cover.1564091601.git.amit.kucheria@linaro.org>
 <20190726103605.GB3327@onstation.org>
 <CAHLCerOs3cMQrWrYk7F_bnxr_nxJ-nsRL8oOGALU63ySqmLaig@mail.gmail.com>
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Hi Amit,

On Fri, Jul 26, 2019 at 04:40:16PM +0530, Amit Kucheria wrote:
> > The device tree nodes appear in sysfs:
> >
> > / # ls -1 /sys/class/thermal/
> > cooling_device0
> > cooling_device1
> > thermal_zone0
> > thermal_zone1
> > thermal_zone2
> > thermal_zone3
> > thermal_zone4
> > thermal_zone5
> > thermal_zone6
> > thermal_zone7
> > thermal_zone8
> > thermal_zone9
> 
> Looks good. What are the contents of the files inside the two
> cooling_device directories? The output of the following command would
> be nice:
> 
> $ grep "" cooling_device?/*

/sys/class/thermal # grep "" cooling_device?/*
cooling_device0/cur_state:100000
cooling_device0/max_state:2500000
cooling_device0/type:smbb-usbin
cooling_device1/cur_state:500000
cooling_device1/max_state:2500000
cooling_device1/type:smbb-dcin

> > The various temperatures were in the upper 40s and I threw some work at
> > all four CPU cores to warm up the phone and watched the various
> > temperatures rise:
> >
> > / # for i in $(seq 0 9) ; do
> > > TYPE=$(cat /sys/class/thermal/thermal_zone$i/type)
> > > TEMP=$(cat /sys/class/thermal/thermal_zone$i/temp)
> > > echo "$TYPE = $TEMP"
> > > done
> > cpu-thermal0 = 66000
> > cpu-thermal1 = 66000
> > cpu-thermal2 = 66000
> > cpu-thermal3 = 66000
> > q6-dsp-thermal = 60000
> > modemtx-thermal = 57000
> > video-thermal = 61000
> > wlan-thermal = 65000
> > gpu-thermal-top = 61000
> > gpu-thermal-bottom = 59000
> >
> > To test the interrupt support, I lowered all of the temperature trips to
> > 51C but I'm not sure where to read that notification. I assume one of
> > the cooling devices or a governor should be started? Sorry but I haven't
> > done any work in the thermal subsystem yet and I'm short on time this
> > morning to investigate right now.
> 
> For now, just checking if the tsens interrupt in /proc/interrupts
> fires should be fine. I have another patch to add some information to
> debugs that I'll send at some point.

An interrupt fires as each thermal zone exceeds the trip temperature and
an interrupt fires again when it goes below that temperature.
Here's my new test script:

for i in $(seq 0 9) ; do
	TYPE=$(cat /sys/class/thermal/thermal_zone$i/type)
	TEMP=$(cat /sys/class/thermal/thermal_zone$i/temp)
	TRIP=$(cat /sys/class/thermal/thermal_zone$i/trip_point_0_temp)
	echo "$TYPE = $TEMP. trip = $TRIP"
done

# Warm the phone up

/sys/class/thermal # /temp.sh 
cpu-thermal0 = 57000. trip = 51000
cpu-thermal1 = 56000. trip = 51000
cpu-thermal2 = 57000. trip = 51000
cpu-thermal3 = 56000. trip = 51000
q6-dsp-thermal = 51000. trip = 51000
modemtx-thermal = 49000. trip = 51000
video-thermal = 53000. trip = 51000
wlan-thermal = 55000. trip = 51000
gpu-thermal-top = 53000. trip = 51000
gpu-thermal-bottom = 52000. trip = 51000

/sys/class/thermal # grep tsens /proc/interrupts 
 27:          8          0          0          0     GIC-0 216 Level     tsens

# Let the phone cool off

/sys/class/thermal # /temp.sh 
cpu-thermal0 = 48000. trip = 51000
cpu-thermal1 = 48000. trip = 51000
cpu-thermal2 = 49000. trip = 51000
cpu-thermal3 = 48000. trip = 51000
q6-dsp-thermal = 47000. trip = 51000
modemtx-thermal = 45000. trip = 51000
video-thermal = 48000. trip = 51000
wlan-thermal = 48000. trip = 51000
gpu-thermal-top = 48000. trip = 51000
gpu-thermal-bottom = 47000. trip = 51000

/sys/class/thermal # grep tsens /proc/interrupts 
 27:         19          0          0          0     GIC-0 216 Level     tsens

> How well does cpufreq work on 8974? I haven't looked at it yet but
> we'll need it for thermal throttling.

I'm not sure how to tell if the frequency is dynamically changed during
runtime on arm. x86-64 shows this information in /proc/cpuinfo. Here's
the /proc/cpuinfo on the Nexus 5:

/sys/class/thermal # cat /proc/cpuinfo 
processor       : 0
model name      : ARMv7 Processor rev 0 (v7l)
BogoMIPS        : 38.40
Features        : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 evtstrm 
CPU implementer : 0x51
CPU architecture: 7
CPU variant     : 0x2
CPU part        : 0x06f
CPU revision    : 0

# 3 more CPUs like 0....

Hardware        : Generic DT based system
Revision        : 0000
Serial          : 0000000000000000

Brian