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 <[email protected]> Cc: Mark Rutland <[email protected]> Signed-off-by: Suzuki K. Poulose <[email protected]> --- 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); + } +} + +/* + * 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) +{ + 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
