Re: [PATCH v2 1/2] thermal: mediatek: Add cpu power cooling model.

dawei chien
2015-10-15T11:31:52Z

On Mon, 2015-10-12 at 18:26 +0100, Punit Agrawal wrote:
> Mark Rutland <mark.rutland@arm.com> writes:
>
> > On Wed, Oct 07, 2015 at 08:22:40PM +0800, Dawei Chien wrote:
> >> From: "Dawei.Chien" <dawei.chien@mediatek.com>
> >>
> >> This power model is base on Intelligent Power Allocation (IPA) technical,
> >> requires that the operating-points of the CPUs are registered using the
> >> kernel's opp library and the `cpufreq_frequency_table` is assigned to the
> >> `struct device` of the cpu MT8173.
> >>
> >> Signed-off-by: Dawei.Chien <dawei.chien@mediatek.com>
> >> ---
> >> This patch is base on
> >> https://patchwork.kernel.org/patch/7034601/
> >> ---
> >> drivers/cpufreq/mt8173-cpufreq.c | 97 +++++++++++++++++++++++++++++++++-----
> >> 1 file changed, 86 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/drivers/cpufreq/mt8173-cpufreq.c b/drivers/cpufreq/mt8173-cpufreq.c
> >> index 49caed2..9233ec5 100644
> >> --- a/drivers/cpufreq/mt8173-cpufreq.c
> >> +++ b/drivers/cpufreq/mt8173-cpufreq.c
> >> @@ -28,7 +28,8 @@
> >> #define MAX_VOLT_SHIFT (200000)
> >> #define MAX_VOLT_LIMIT (1150000)
> >> #define VOLT_TOL (10000)
> >> -
> >> +#define CAPACITANCE_CA53 (263)
> >> +#define CAPACITANCE_CA57 (530)
> >> /*
> >> * The struct mtk_cpu_dvfs_info holds necessary information for doing CPU DVFS
> >> * on each CPU power/clock domain of Mediatek SoCs. Each CPU cluster in
> >> @@ -51,6 +52,72 @@ struct mtk_cpu_dvfs_info {
> >> bool need_voltage_tracking;
> >> };
> >>
> >> +struct mtk_cpu_static_power {
> >> + unsigned long voltage;
> >> + unsigned int power;
> >> +};
> >> +
> >> +/* measured by WA program. */
> >> +static const struct mtk_cpu_static_power mtk_ca53_static_power[] = {
> >> + {859000, 43},
> >> + {908000, 52},
> >> + {983000, 86},
> >> + {1009000, 123},
> >> + {1028000, 138},
> >> + {1083000, 172},
> >> + {1109000, 180},
> >> + {1125000, 192},
> >> +};
> >> +
> >> +/* measured by WA program. */
> >> +static const struct mtk_cpu_static_power mtk_ca57_static_power[] = {
> >> + {828000, 72},
> >> + {867000, 90},
> >> + {927000, 156},
> >> + {968000, 181},
> >> + {1007000, 298},
> >> + {1049000, 435},
> >> + {1089000, 533},
> >> + {1125000, 533},
> >> +};
> >
> > This should be described in the DT, rather than necessitating tonnes of
> > these tables in the kernel.
>
> The above table is a simplification that is tying the static power of a
> device to a voltage (indirectly via frequency for ease of indexing
> perhaps).
>
> We should definitely look at describing the static power model in the
> device tree - but it is not entirely clear what is the best model to
> use as basis for the device tree bindings.
>
> Static power consumption depends on a few different parameters (silicon
> process, voltage, temperature, etc.). The relationship between them
> maybe non-linear and not all of these maybe significant for a given
> platform. e.g., for Juno, we are using a regression based on voltage and
> temperature which was deemed close enough (very subjective tbh).
>
> On the other hand, dynamic power consumption is somewhat simpler and I
> have patches[0][1][2] enabling it's description in device tree. Your comments
> there would be very much appreciated.
>
> As for this patch, I hope it can be moved to using the device tree when
> the bindings for static power are agreed upon. Although sub-optimal, I
> can't see any other way forward for now.
>
> [0] http://thread.gmane.org/gmane.linux.kernel/2011466/focus=130373
> [1] http://thread.gmane.org/gmane.linux.kernel/2011466/focus=2011465
> [2] http://article.gmane.org/gmane.linux.drivers.sensors/37859

Hi Mark/Punit,
Thank you for your nice comments. I will resend this patch with device tree for dynamic/static power model,
and refer to Punit's patches, thank you.

> >
> > Mark.
> > --
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