On 14-08-15, 18:56, Javi Merino wrote:
> The OPP library is now used for power models to calculate the power
> that a device would consume at a specific OPP. To do that, we use a
> simple power model which takes frequency and voltage as inputs. We get
> the voltage and frequency from the OPP library.
>
> The devfreq cooling device for the thermal framework controls temperature
> by disabling OPPs. The power model needs to calculate the power that
> would be consumed if we reenabled the OPP. dev_pm_opp_get_voltage()
> doesn't work for disabled OPPs.
>
> Add a dev_pm_opp_get_voltage_always() that works both for enabled and
> disabled OPPs to be used by the power model. The documentation for this
> function clearly states that you should use dev_pm_opp_get_voltage()
> instead unless you know what you're doing.
>
> Cc: "Rafael J. Wysocki" <r...@rjwysocki.net>
> Cc: Viresh Kumar <viresh.ku...@linaro.org>
> Signed-off-by: Javi Merino <javi.mer...@arm.com>
> ---
> drivers/base/power/opp.c | 37 +++++++++++++++++++++++++++++++++++++
> include/linux/pm_opp.h | 7 +++++++
> 2 files changed, 44 insertions(+)
>
> diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
> index 677fb2843553..b1a4216c7ec3 100644
> --- a/drivers/base/power/opp.c
> +++ b/drivers/base/power/opp.c
> @@ -182,6 +182,43 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp
> *opp)
> EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage);
>
> /**
> + * dev_pm_opp_get_voltage_always() - Gets the voltage corresponding to an opp
> + * @opp: opp for which voltage has to be returned for
> + *
> + * This function is similar to dev_pm_opp_get_voltage() except that it
> + * works for disabled opps as well. In most cases, you want to
> + * operate only on available opps so you should use
> + * dev_pm_opp_get_voltage() instead.
> + *
> + * Return: voltage in micro volt corresponding to the opp, else
> + * return 0
> + *
> + * Locking: This function must be called under rcu_read_lock(). opp is a rcu
> + * protected pointer. This means that opp which could have been fetched by
> + * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
> + * under RCU lock. The pointer returned by the opp_find_freq family must be
> + * used in the same section as the usage of this function with the pointer
> + * prior to unlocking with rcu_read_unlock() to maintain the integrity of the
> + * pointer.
> + */
> +unsigned long dev_pm_opp_get_voltage_always(struct dev_pm_opp *opp)
> +{
> + struct dev_pm_opp *tmp_opp;
> + unsigned long v = 0;
> +
> + opp_rcu_lockdep_assert();
> +
> + tmp_opp = rcu_dereference(opp);
> + if (unlikely(IS_ERR_OR_NULL(tmp_opp)))
> + pr_err("%s: Invalid parameters\n", __func__);
> + else
> + v = tmp_opp->u_volt;
> +
> + return v;
> +}
> +EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage_always);
I will rather update dev_pm_opp_get_voltage() and remove the
'available' check. There is no need for that.
--
viresh
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
