From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751440AbbATFpK (ORCPT ); Tue, 20 Jan 2015 00:45:10 -0500 Received: from ozlabs.org ([103.22.144.67]:44834 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750704AbbATFpJ (ORCPT ); Tue, 20 Jan 2015 00:45:09 -0500 In-Reply-To: <20150119113251.23984.16931.stgit@preeti.in.ibm.com> To: Preeti U Murthy , rafael.j.wysocki@intel.com From: Michael Ellerman Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: cpuidle/powernv: Read target_residency value of idle states from DT if available Message-Id: <20150120054506.F13591402E0@ozlabs.org> Date: Tue, 20 Jan 2015 16:45:06 +1100 (AEDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2015-19-01 at 11:32:51 UTC, Preeti U Murthy wrote: > The device tree now exposes the residency values for different idle states. Read > these values instead of calculating residency from the latency values. The values > exposed in the DT are validated for optimal power efficiency. However to maintain > compatibility with the older firmware code which does not expose residency > values, use default values as a fallback mechanism. While at it, clump > the common parts of device tree parsing into one chunk. > > Signed-off-by: Preeti U Murthy > --- > > drivers/cpuidle/cpuidle-powernv.c | 39 ++++++++++++++++++++++++------------- > 1 file changed, 25 insertions(+), 14 deletions(-) > > diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c > index 2726663..9e732e1 100644 > --- a/drivers/cpuidle/cpuidle-powernv.c > +++ b/drivers/cpuidle/cpuidle-powernv.c > @@ -162,7 +162,8 @@ static int powernv_add_idle_states(void) > int dt_idle_states; > const __be32 *idle_state_flags; > const __be32 *idle_state_latency; > - u32 len_flags, flags, latency_ns; > + const __be32 *idle_state_residency; > + u32 len_flags, flags, latency_ns, residency_ns; > int i; > > /* Currently we have snooze statically defined */ > @@ -186,14 +187,21 @@ static int powernv_add_idle_states(void) > return nr_idle_states; > } > > + idle_state_residency = of_get_property(power_mgt, > + "ibm,cpu-idle-state-residency-ns", NULL); > + if (!idle_state_residency) { > + pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-residency-ns\n"); > + pr_warn("Falling back to default values\n"); > + } This would be better done with something like: rc = of_read_property_u32(power_mgt, "ibm,cpu-idle-state-residency-ns", &residency_ns); if (!rc) { pr_info("cpuidle-powernv: missing ibm,cpu-idle-state-residency-ns\n"); residency_ns = 300000; } cheers