Re: [PATCH v1 3/3] PM / AVS: rockchip-cpu-avs: add driver handling Rockchip cpu avs

[Finley Xiao]

å 2016/8/23 17:03, Heiko StÃbner åé:
> Hi Finley,
>
> Am Dienstag, 23. August 2016, 12:10:27 schrieb Finley Xiao:
> > å 2016/8/19 21:36, Rob Herring åé:
> > > On Tue, Aug 16, 2016 at 10:38:59AM +0800, Finlye Xiao wrote:
> > > > From: Finley Xiao <finley.xiao@xxxxxxxxxxxxxx>
> > > >
> > > > This patch supports adjusting opp's voltage according to leakage
> > > >
> > > > Signed-off-by: Finley Xiao <finley.xiao@xxxxxxxxxxxxxx>
> > > > ---
> > > >
> > > >    .../devicetree/bindings/power/rockchip-cpu-avs.txt |  37 +++
> > > >    drivers/power/avs/Kconfig                          |   8 +
> > > >    drivers/power/avs/Makefile                         |   1 +
> > > >    drivers/power/avs/rockchip-cpu-avs.c               | 314
> > > >    +++++++++++++++++++++ 4 files changed, 360 insertions(+)
> > > >    create mode 100644
> > > >    Documentation/devicetree/bindings/power/rockchip-cpu-avs.txt create
> > > >    mode 100644 drivers/power/avs/rockchip-cpu-avs.c
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/power/rockchip-cpu-avs.txt
> > > > b/Documentation/devicetree/bindings/power/rockchip-cpu-avs.txt new file
> > > > mode 100644
> > > > index 0000000..90f6b08
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/power/rockchip-cpu-avs.txt
> > > > @@ -0,0 +1,37 @@
> > > > +Rockchip cpu avs device tree bindings
> > > > +-------------------------------------
> > > > +
> > > > +Under the same frequency, the operating voltage tends to decrease with
> > > > +increasing leakage. so it is necessary to adjust opp's voltage according
> > > > +to leakage for power.
> > > > +
> > > > +
> > > > +Required properties:
> > > > +- compatible: Should be one of the following.
> > > > +  - "rockchip,rk3399-cpu-avs" - for RK3399 SoCs.
> > > > +- leakage-volt-<name>: Named leakage-volt property. At runtime, the
> > > > +  platform can find a cpu's cluster_id according to it's cpu_id and
> > > > match
> > > > +  leakage-volt-<name> property. The property is an array of 3-tuples
> > > > +  items, and each item consists of leakage and voltage like
> > > > +  <min-leakage-mA max-leakage-mA vol-uV>.
> > > > +	min-leakage: minimum leakage in mA.
> > > > +	max-leakage: maximum leakage in mA.
> > > > +	vol: voltage in microvolt.
> > > How do you determine these values? When do they vary?
> > How do you determine these values?
> >
> > run antutu-benchmark
> > leakage     freq 	min_volt
> > 30mA 	    1608MHz 	1025mV
> > 40mA 	    1608MHz 	1000mV
> > 50mA 	    1608MHz 	975mV
> >
> >   From the table, we see the min_volt decrease with increasing leakage.
> > So we can set the default opp-microvolt 1025mV for 1608MHz,
> > and add an leakage_volt_cluster0 property as follows.
> > leakage_volt_cluster0 = <
> > 		/*  min(mA)   max(mA)    volt(uV)*/
> > 		    0         40        0
> > 		    41        50        (-25000)
> > 		    51        254       (-50000)
> >
> > > ;
> > If the leakage is between 41mA and 50mAïthe opp-microvolt will subtract
> > 25mVã If the leakage is between 41mA and 50mAïthe opp-microvolt will
> > subtract 50mVã
> >
> > When do they vary?
> >
> >   From the code,
> > cpufreq_online
> > --cpufreq_driver->init(policy);  /* add new opp table */
> > --blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
> > CPUFREQ_START, policy);
> > --cpufreq_init_policy
> > ----cpufreq_set_policy
> > --------__cpufreq_governor(policy, CPUFREQ_GOV_START);
> >
> > The cpu's opp table is added in the init function(cpufreq_init)ïand I will
> > register a cpufreq notifier, once the first cpu of cluster is onlined,
> > my notifer will be called, and if the event is CPUFREQ_STARTïit will modify
> > the opp-microvolt according to leakage_volt_cluster0.
> I think what Rob was asking with "when do they vary" is, are these leakage
> values the same for each and every rk3399 soc or are they determined
> separately for each board-type using the rk3399.

Oh, sorry, I misunderstood.
They are the same for every rk3399 soc.

>

--
Finley