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Message-ID: <9hhh9p3caxm.fsf@e105922-lin.cambridge.arm.com>
Date: Fri, 17 Jul 2015 11:53:25 +0100
From: Punit Agrawal <punit.agrawal@....com>
To: Chanwoo Choi <cw00.choi@...sung.com>
Cc: edubezval@...il.com, rui.zhang@...el.com, myungjoo.ham@...sung.com,
kyungmin.park@...sung.com, ulf.hansson@...aro.org,
khilman@...aro.org, robh+dt@...nel.org, pawel.moll@....com,
mark.rutland@....com, ijc+devicetree@...lion.org.uk,
inki.dae@...sung.com, l.majewski@...sung.com,
kgene.kim@...sung.com, linux-pm@...r.kernel.org,
linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [RFC PATCH 0/2] thermal: Add generic devfreq cooling device
Hi Chanwoo,
Chanwoo Choi <cw00.choi@...sung.com> writes:
> This patchset introduce the generic devfreq cooling device for generic thermal
> framework. The devfreq devices are used ad cooling device to reduce the
> overheating temperature. This patch is based on drivers/thermal/cpu_cooling.c.
> The devfreq cooling device can change the ragne of the frequency table of
> devfreq device according to cooling level in device tree file.
>
Have you had a look at the devfreq cooling patches from Javi[0][1]? How
is the current patchset different?
At first glance, it seems that you are not implementing the extensions
that allow devfreq cooling devices to be used with power_allocator
thermal governor that got merged in v4.2-rc1.
Thanks,
Punit
[0] http://article.gmane.org/gmane.linux.power-management.general/61936
[1] http://article.gmane.org/gmane.linux.power-management.general/62417
> To verify the devfreq cooling device driver, I testd it with following platform:
>
> For example,
> - The Mali GPU of Exynos5433 SoC uses the devfreq framework to support the DVFS
> feature and Exynos5433 contains the G3D (GPU) thermal sensor. Following example
> explain the correlation between mali dt node and thermal sensor/zone.
> : thermal sensor : G3D sensor of Samsung Exynos5433 [1][2]
> : devfreq cooling device : Mali GPU [3]
>
> According to the temperature of g3d thermal sensor inclued in Exynos5433,
> devfreq cooling device can change the maximum frequency of Mali GPU.
>
> 1. In Exynos5433-based board dts file, Mali GPU dt node uses the devfreq
> framework to suppot the DVFS feature. Following dt node includes the
> both 'cooling-cells' and 'operating-points' which means the supported
> frequency entries:
>
> mali: mali@...C0000 {
> compatible = "arm,mali-midgard";
> reg = <0x14AC0000 0x5000>;
> interrupts = <0 282 0>, <0 283 0>, <0 281 0>;
> interrupt-names = "JOB", "MMU", "GPU";
> clocks = <&cmu_g3d CLK_ACLK_G3D>;
> clock-names = "clk_mali";
> power-domains = <&pd_g3d>;
> status = "disabled";
>
> #cooling-cells = <2>;
>
> operating-points = <
> 700000 1150000
> 600000 1150000
> 550000 1125000
> 500000 1075000
> 420000 1025000
> 350000 1025000
> 266000 1000000
> 160000 1000000
> >;
> };
>
> 2. In exynos5433.dtsi, G3D thermal sensor measure the temperature of Mali GPU:
>
> tmu_g3d: tmu@...70000 {
> compatible = "samsung,exynos5433-tmu";
> reg = <0x10070000 0x200>;
> interrupts = <0 99 0>;
> clocks = <&cmu_peris CLK_PCLK_TMU1_APBIF>,
> <&cmu_peris CLK_SCLK_TMU1>;
> clock-names = "tmu_apbif", "tmu_sclk";
> #include "exynos5433-tmu-sensor-conf.dtsi"
> status = "disabled";
> };
>
> 3. In exynos5433-tmu.dtsi, thermal-zones includes both trip points and
> cooling-maps of g3d thermal sensor. Following cooling-maps show the match
> between each trip point and each cooling device (devfreq device of mali):
>
> thermal-zones {
> /* ...... */
> g3d_thermal: g3d-thermal {
> thermal-sensors = <&tmu_g3d>;
> polling-delay-passive = <0>;
> polling-delay = <0>;
> trips {
> g3d_alert_0: g3d-alert-0 {
> temperature = <30000>; /* millicelsius */
> hysteresis = <10000>; /* millicelsius */
> type = "active";
> };
> g3d_alert_1: g3d-alert-1 {
> temperature = <40000>; /* millicelsius */
> hysteresis = <10000>; /* millicelsius */
> type = "active";
> };
>
> /* ...... */
> };
>
> cooling-maps {
> map0 {
> /* Set maximum frequency as 550MHz */
> trip = <&g3d_alert_0>;
> cooling-device = <&mali 2 2>;
> };
> map1 {
> /* Set maximum frequency as 420MHz */
> trip = <&g3d_alert_1>;
> cooling-device = <&mali 4 4>;
> };
>
> /* ...... */
> };
> };
>
> ......
> };
>
> [1] https://git.kernel.org/cgit/linux/kernel/git/kgene/linux-samsung.git/commit/?h=v4.3-next/dt64-samsung&id=ac008f6b537703bb9a6fcc3882ca4af3331aa24f
> [2] https://git.kernel.org/cgit/linux/kernel/git/kgene/linux-samsung.git/commit/?h=v4.3-next/dt64-samsung&id=bcddc3a84e49ca1c646cf2081687a544a15f9218
> [3] malideveloper.arm.com/downloads/drivers/TX041/r5p0-06rel0/TX041-SW-99002-r5p0-06rel0.tgz
>
> Chanwoo Choi (2):
> PM: devfreq: Add the prototype of update_devfreq() to export
> thermal: devfreq_cooling: Add generic devfreq cooling device implementaion
>
> .../devicetree/bindings/thermal/thermal.txt | 8 +-
> drivers/devfreq/devfreq.c | 22 +-
> drivers/thermal/Kconfig | 11 +
> drivers/thermal/Makefile | 3 +
> drivers/thermal/devfreq-cooling.c | 309 +++++++++++++++++++++
> include/linux/devfreq-cooling.h | 80 ++++++
> include/linux/devfreq.h | 7 +
> 7 files changed, 425 insertions(+), 15 deletions(-)
> create mode 100644 drivers/thermal/devfreq-cooling.c
> create mode 100644 include/linux/devfreq-cooling.h
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