Hi Adam, On 12/09/2019 23:19, Adam Ford wrote: > On Thu, Sep 12, 2019 at 4:12 PM Daniel Lezcano > <daniel.lezcano@xxxxxxxxxx> wrote: >> >> On 12/09/2019 20:30, Adam Ford wrote: >>> The thermal sensor in the omap3 family isn't accurate, but it's >>> better than nothing. The various OPP's enabled for the omap3630 >>> support up to OPP1G, however the datasheet for the DM3730 states >>> that OPP130 and OPP1G are not available above TJ of 90C. >>> >>> This patch configures the thermal throttling to limit the >>> operating points of the omap3630 to Only OPP50 and OPP100 if >>> the thermal sensor reads a value above 90C. Oh, that's a very interesting use case. AFAICT the thermal framework is not designed to deal with this situation. I agree this setup may work (even if I'm not convinced about the stability of the whole). May be Viresh can help for the cpufreq side? >> Out of curiosity, what are the OPP50 and OPP100 mentioned above? and >> what does mean "OPP130 and OPP1G are not available above TJ of 90C"? >> > OPP130 is the 800 MHz and OPP1G is 1GHz operating point. > The 90C is the max junction temperature. When the temperature exceeds > 90C, the processor is not designed to operate at 800+ MHz. The > statement itself is a direct quote from the public datasheet for the > dm3730, Table 4-19. > The datasheet is: http://www.ti.com/lit/ds/symlink/dm3730.pdf It is ambiguous how it is stated: "OPP130 and OPP1G are not available above TJ of 90C" that can be interpreted the OPP is disabled by the hardware, no? > The operating points were updated in [1], but they haven't yet been > fully applied yet, but during the discussion, the question came about > regarding how to limit the speed at high temp, so that's why this > patch was done. > > [1] - https://patchwork.kernel.org/patch/11141643/ I see, you switched to opp-v2. Thanks for the detailed answer. >> I don't see the connection between these OPP names and the definition in >> the DT. >> >>> Signed-off-by: Adam Ford <aford173@xxxxxxxxx> >>> >>> diff --git a/arch/arm/boot/dts/omap36xx.dtsi b/arch/arm/boot/dts/omap36xx.dtsi >>> index 4bb4f534afe2..58b9d347019f 100644 >>> --- a/arch/arm/boot/dts/omap36xx.dtsi >>> +++ b/arch/arm/boot/dts/omap36xx.dtsi >>> @@ -25,6 +25,7 @@ >>> >>> vbb-supply = <&abb_mpu_iva>; >>> clock-latency = <300000>; /* From omap-cpufreq driver */ >>> + #cooling-cells = <2>; >>> }; >>> }; >>> >>> @@ -195,6 +196,31 @@ >>> }; >>> }; >>> >>> +&cpu_thermal { >>> + cpu_trips: trips { >>> + /* OPP130 and OPP1G are not available above TJ of 90C. */ >>> + cpu_alert0: cpu_alert { >>> + temperature = <90000>; /* millicelsius */ >>> + hysteresis = <2000>; /* millicelsius */ >>> + type = "passive"; >>> + }; >>> + >>> + cpu_crit: cpu_crit { >>> + temperature = <125000>; /* millicelsius */ >>> + hysteresis = <2000>; /* millicelsius */ >>> + type = "critical"; >>> + }; >>> + }; >>> + >>> + cpu_cooling_maps: cooling-maps { >>> + map0 { >>> + trip = <&cpu_alert0>; >>> + /* Only allow OPP50 and OPP100 */ >>> + cooling-device = <&cpu 0 1>; >>> + }; >>> + }; >>> +}; >>> + >>> /* OMAP3630 needs dss_96m_fck for VENC */ >>> &venc { >>> clocks = <&dss_tv_fck>, <&dss_96m_fck>; >>> >> >> >> -- >> <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs >> >> Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | >> <http://twitter.com/#!/linaroorg> Twitter | >> <http://www.linaro.org/linaro-blog/> Blog >> -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
