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arm-cci: Add routines to save/restore all counters

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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 <punit.agrawal@arm.com>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Suzuki K Poulose 2016-02-23 10:49:50 +00:00 committed by Will Deacon
parent 1ce6311b99
commit cea16f8ba7
1 changed files with 38 additions and 0 deletions
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38
drivers/bus/arm-cci.c
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@ -718,6 +718,44 @@ static void pmu_set_event(struct cci_pmu *cci_pmu, int idx, unsigned long event)
pmu_write_register(cci_pmu, event, 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).
*
* @mask should be initialised to empty by the caller.
*/
static void __maybe_unused
pmu_save_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);
}
}
}
/*
* Restore the status of the counters. Reversal of the pmu_save_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