Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753345AbbHQJG0 (ORCPT ); Mon, 17 Aug 2015 05:06:26 -0400 Received: from fw-tnat.cambridge.arm.com ([217.140.96.140]:55849 "EHLO cam-smtp0.cambridge.arm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753631AbbHQJGY (ORCPT ); Mon, 17 Aug 2015 05:06:24 -0400 Date: Mon, 17 Aug 2015 10:05:48 +0100 From: Javi Merino To: Viresh Kumar Cc: "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "cw00.choi@samsung.com" , "rufus.hamade@imgtec.com" , "Rafael J. Wysocki" Subject: Re: [PATCH v4 2/5] PM / OPP: add a function to get the voltage for disabled OPPs Message-ID: <20150817090548.GA2762@e104805> References: <1439575020-3447-1-git-send-email-javi.merino@arm.com> <1439575020-3447-3-git-send-email-javi.merino@arm.com> <20150815055925.GJ1162@linux> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20150815055925.GJ1162@linux> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3443 Lines: 81 On Sat, Aug 15, 2015 at 06:59:25AM +0100, Viresh Kumar wrote: > 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" > > Cc: Viresh Kumar > > Signed-off-by: Javi Merino > > --- > > 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. Even better, I'll do that for the next version. Cheers, Javi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/