From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754556AbbLJPcg (ORCPT ); Thu, 10 Dec 2015 10:32:36 -0500 Received: from foss.arm.com ([217.140.101.70]:55794 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753409AbbLJPcf (ORCPT ); Thu, 10 Dec 2015 10:32:35 -0500 Date: Thu, 10 Dec 2015 15:32:23 +0000 From: Mark Rutland To: "Suzuki K. Poulose" Cc: linux-arm-kernel@lists.infradead.org, punit.agrawal@arm.com, arm@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCHv3 3/5] arm-cci: Add routines to enable/disable all counters Message-ID: <20151210153222.GE495@leverpostej> References: <1447783407-18027-1-git-send-email-suzuki.poulose@arm.com> <1447783407-18027-4-git-send-email-suzuki.poulose@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1447783407-18027-4-git-send-email-suzuki.poulose@arm.com> 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 On Tue, Nov 17, 2015 at 06:03:25PM +0000, Suzuki K. Poulose wrote: > Adds helper routines to disable the counter controls for > all the counters on the CCI PMU and restore it back, by > preserving the original state in caller provided mask. > > Cc: Punit Agrawal > Cc: Mark Rutland > Signed-off-by: Suzuki K. Poulose > --- > Changes since V2: > - Rename the functions to pmu_restore_counters, pmu_disable_counters > - Added comment describing why we use a private mask > --- > drivers/bus/arm-cci.c | 38 ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 38 insertions(+) > > diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c > index 48936c8..91a9d5d 100644 > --- a/drivers/bus/arm-cci.c > +++ b/drivers/bus/arm-cci.c > @@ -669,6 +669,44 @@ pmu_get_event(struct cci_pmu *cci_pmu, int idx) > return pmu_read_register(cci_pmu, idx, CCI_PMU_EVT_SEL); > } > > + > +/* > + * For all counters on the CCI-PMU, disable any 'enabled' counters, > + * saving the changed counters in the mask, so that we can restore > + * it later using pmu_restore_counters. The mask is private to the > + * caller. We cannot rely on the used_mask maintained by the CCI_PMU > + * as it only tells us if the counter is assigned to perf_event or not. > + * The state of the perf_event cannot be locked by the PMU layer, hence > + * we check the individual counter status (which can be locked by > + * cci_pm->hw_events->pmu_lock). > + */ > +static void __maybe_unused > +pmu_disable_counters(struct cci_pmu *cci_pmu, unsigned long *mask) > +{ > + int i; > + > + for (i = 0; i < cci_pmu->num_cntrs; i++) { > + if (pmu_counter_is_enabled(cci_pmu, i)) { > + set_bit(i, mask); > + pmu_disable_counter(cci_pmu, i); > + } else > + clear_bit(i, mask); Can we not assume a clean mask to begin with? > + } > +} > + > +/* > + * Restore the status of the counters. Reversal of the pmu_disable_counters(). > + * For each counter set in the mask, enable the counter back. > + */ > +static void __maybe_unused > +pmu_restore_counters(struct cci_pmu *cci_pmu, unsigned long *mask) This would probably be better with s/restore/enable/ for consistency with pmu_disable_counters. Other than that this looks fine to me. Mark. > +{ > + int i; > + > + for_each_set_bit(i, mask, cci_pmu->num_cntrs) > + pmu_enable_counter(cci_pmu, i); > +} > + > /* > * Returns the number of programmable counters actually implemented > * by the cci > -- > 1.7.9.5 >