[v3,0/2] thermal: mediatek: Add cpu power cooling model

Commit Message

Dawei Chien Nov. 5, 2015, 11:09 a.m. UTC

On Mon, 2015-11-02 at 17:40 +0530, Viresh Kumar wrote:
> On 02-11-15, 18:46, dawei chien wrote:
> > On Wed, 2015-10-28 at 21:14 +0530, Viresh Kumar wrote:
> > > Sorry for being extremely late in reviewing this stuff. You are
> > > already on v3 and I haven't reviewed it once. Mostly due to bad timing
> > > of my holidays and other work pressure.
> > 
> > You're welcome, truly thank you for your kindly reviewing
> 
> Thanks for understanding.
> 
> > > Now, there are few things that I feel are not properly addressed here,
> > > and I may be wrong:
> > > - Where are the bindings for static-power-points and
> > >   dynamic-power-coefficient. Sorry I failed to see them in this or
> > >   other series you mentioned.
> > 
> > Please refer to following document (2-1,2-2) for dynamic-power &
> > static-power in detail. Besides, do I need to add another document for
> > our own MT8173 IC.
> > http://lxr.free-electrons.com/source/Documentation/thermal/cpu-cooling-api.txt
> 
> That's about the power-API, but I am talking about the Device Tree
> bindings here. So, when you add any new DT bindings (Or a new property
> in device tree blobs), you need to add its documentation in
> Documentation/devicetree/bindings/... and get it approved by DT
> maintainers as well. You perhaps missed that completely, otherwise you
> would have been told really early that the new bindings aren't going
> to help.

Thank you for your kindly explaining, now I could understand what I
miss, I will send device tree binding on next version such like
following description.

> > >   voltage/power ? And not reuse and extend the opp-v2 stuff which is
> > >   already mainlined now.
> > 
> > We could reuse opp-v2 for static power points after OPPV2 back port to
> > our currently branch.
> 
> Your current branch doesn't matter to us. All that matters here is
> mainline, that's where you are adding code to. And you must test your
> stuff on the latest upstream branch only, not on some old kernel
> release. You can include other dependency patches though, that are
> required to make it work and mention them in cover-letter.

Thank you for your kindly explaining, Now I know I should develop and
test on mainline branch since this is where I try to add code.

However, please understanding currently mt8173_cpufreq.c is not ready
for OPPV2 in mainline as far, that's the reason why currently I can't
reuse OPPV2 and extend for static power table. My propose is for adding
CPU cooling device for our own product.

Actually, I would like to remove static power table on next patch since
static power is optional and dynamic power is much more than static
power.

> > However, as far as I know, there is no "power" in opp.c (suck like
> 
> s/suck/such ?
> 
> > opp-hz) as far, so I need to add something in opp.c for my purpose, suck
> > like add power in _opp_add_static_v2, and add something for return
> > "power", right? I may be wrong, please kindly give me your suggestion,
> > thank you.
> 
> You first need to propose a change in DT bindings for OPPs:
> Documentation/devicetree/bindings/opp/opp.txt
> 
> And then we can change the code properly.
> 
> > Actually, I am considering to remove the part of static power point
> > since it is optional for Power Model. Could you agree with this?
> 
> If its not important for your platform, then I don't have any issues
> with that..
> 


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Comments

Viresh Kumar Nov. 6, 2015, 3:20 a.m. UTC | #1

On 05-11-15, 19:09, dawei chien wrote:
> Thank you for your kindly explaining, now I could understand what I
> miss, I will send device tree binding on next version such like
> following description.
> 
> --- a/Documentation/devicetree/bindings/clock/mt8173-cpu-dvfs.txt
> +++ b/Documentation/devicetree/bindings/clock/mt8173-cpu-dvfs.txt
> @@ -10,6 +10,17 @@ Required properties:
>         Please refer to
> Documentation/devicetree/bindings/clk/clock-bindings.txt for
>         generic clock consumer properties.
>  - proc-supply: Regulator for Vproc of CPU cluster.
> +- dynamic-power-coefficient:
> +       Usage: optional
> +       Value type: <prop-encoded-array>
> +       Definition: A u32 value that represents an indicative
> +       running time dynamic power coefficient in
> +       fundamental units of mW/MHz/uVolt^2.
> +       The dynamic energy consumption of the CPU
> +       is proportional to the square of the
> +       Voltage (V) and the clock frequency (f).
> +       Pdyn = dynamic-power-coefficient * V^2 * f
> +       where voltage is in uV, frequency is in MHz.

Please check with Punit if he is planning to add the same..

> Thank you for your kindly explaining, Now I know I should develop and
> test on mainline branch since this is where I try to add code.
> 
> However, please understanding currently mt8173_cpufreq.c is not ready
> for OPPV2 in mainline as far, that's the reason why currently I can't
> reuse OPPV2 and extend for static power table. My propose is for adding
> CPU cooling device for our own product.

Firstly, we don't care. You are pushing something to mainline, you
have to get it tested someway on mainline.

Secondly, there are *almost* no changes required to the mtk cpufreq
driver for OPPV2. Just update your DT in a similar way it is done for
one of the exynos platforms and it should just work fine.

Dawei Chien Nov. 11, 2015, noon UTC | #2

On Fri, 2015-11-06 at 08:50 +0530, Viresh Kumar wrote:
> On 05-11-15, 19:09, dawei chien wrote:
> > Thank you for your kindly explaining, now I could understand what I
> > miss, I will send device tree binding on next version such like
> > following description.
> > 
> > --- a/Documentation/devicetree/bindings/clock/mt8173-cpu-dvfs.txt
> > +++ b/Documentation/devicetree/bindings/clock/mt8173-cpu-dvfs.txt
> > @@ -10,6 +10,17 @@ Required properties:
> >         Please refer to
> > Documentation/devicetree/bindings/clk/clock-bindings.txt for
> >         generic clock consumer properties.
> >  - proc-supply: Regulator for Vproc of CPU cluster.
> > +- dynamic-power-coefficient:
> > +       Usage: optional
> > +       Value type: <prop-encoded-array>
> > +       Definition: A u32 value that represents an indicative
> > +       running time dynamic power coefficient in
> > +       fundamental units of mW/MHz/uVolt^2.
> > +       The dynamic energy consumption of the CPU
> > +       is proportional to the square of the
> > +       Voltage (V) and the clock frequency (f).
> > +       Pdyn = dynamic-power-coefficient * V^2 * f
> > +       where voltage is in uV, frequency is in MHz.
> 
> Please check with Punit if he is planning to add the same.
Punit just sent the patch for this binding[1] yesterday, so I will re-send next version once his patch has been reviewed.
> > Thank you for your kindly explaining, Now I know I should develop and
> > test on mainline branch since this is where I try to add code.
> > 
> > However, please understanding currently mt8173_cpufreq.c is not ready
> > for OPPV2 in mainline as far, that's the reason why currently I can't
> > reuse OPPV2 and extend for static power table. My propose is for adding
> > CPU cooling device for our own product.
> 
> Firstly, we don't care. You are pushing something to mainline, you
> have to get it tested someway on mainline.
> 
> Secondly, there are *almost* no changes required to the mtk cpufreq
> driver for OPPV2. Just update your DT in a similar way it is done for
> one of the exynos platforms and it should just work fine.
> 
In our platform, thermal throttling is good enough with dynamic power
only, so my plan is to send dynamic power model first in next version.

Regarding static power model, we will continue discussing with ARM to
find a better solution.

Thanks.

[1] https://lkml.org/lkml/2015/11/9/542

BR,
Dawei


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Patch

--- a/Documentation/devicetree/bindings/clock/mt8173-cpu-dvfs.txt
+++ b/Documentation/devicetree/bindings/clock/mt8173-cpu-dvfs.txt
@@ -10,6 +10,17 @@  Required properties:
        Please refer to
Documentation/devicetree/bindings/clk/clock-bindings.txt for
        generic clock consumer properties.
 - proc-supply: Regulator for Vproc of CPU cluster.
+- dynamic-power-coefficient:
+       Usage: optional
+       Value type: <prop-encoded-array>
+       Definition: A u32 value that represents an indicative
+       running time dynamic power coefficient in
+       fundamental units of mW/MHz/uVolt^2.
+       The dynamic energy consumption of the CPU
+       is proportional to the square of the
+       Voltage (V) and the clock frequency (f).
+       Pdyn = dynamic-power-coefficient * V^2 * f
+       where voltage is in uV, frequency is in MHz.

> > > - Even then, why should we be adding another table into DT for