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[PATCH v5 07/11] arm-cci: Add routines to save/restore all counters

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  [PATCH v5 07/11] arm-cci: Add routines to save/restore all counters "Suzuki K. Poulose" <suzuki.poulose@arm.com> - 2016-01-04 13:00 +0100
    Re: [PATCH v5 07/11] arm-cci: Add routines to save/restore all  counters "Suzuki K. Poulose" <Suzuki.Poulose@arm.com> - 2016-01-11 12:00 +0100
    Re: [PATCH v5 07/11] arm-cci: Add routines to save/restore all  counters Mark Rutland <mark.rutland@arm.com> - 2016-01-11 12:00 +0100

#1300674 — [PATCH v5 07/11] arm-cci: Add routines to save/restore all counters

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>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
---
 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 a3938ef..2f1fcf0 100644
--- a/drivers/bus/arm-cci.c
+++ b/drivers/bus/arm-cci.c
@@ -672,6 +672,44 @@ static void pmu_set_event(struct cci_pmu *cci_pmu, int idx, unsigned long event)
 }
 
 /*
+ * 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 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_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

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#1306062 — Re: [PATCH v5 07/11] arm-cci: Add routines to save/restore all counters

On 11/01/16 10:50, Mark Rutland wrote:
> On Mon, Jan 04, 2016 at 11:54:46AM +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 <punit.agrawal@arm.com>
>> Cc: Mark Rutland <mark.rutland@arm.com>
>> Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
>> ---
>>   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 a3938ef..2f1fcf0 100644
>> --- a/drivers/bus/arm-cci.c
>> +++ b/drivers/bus/arm-cci.c
>> @@ -672,6 +672,44 @@ static void pmu_set_event(struct cci_pmu *cci_pmu, int idx, unsigned long event)
>>   }
>>
>>   /*
>> + * 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 by the caller.
>
> We should probably state "initialised to zero", or "empty".

Yep, will fix it.

>> +/*
>> + * Restore the status of the counters. Reversal of the pmu_disable_counters().
>> + * For each counter set in the mask, enable the counter back.
>> + */
>
> Shouldn't that say pmu_save_counters?

Yea, missed it in rebase.

> With that:
>
> Acked-by: Mark Rutland <mark.rutland@arm.com>
>

Thanks
Suzuki

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#1306067 — Re: [PATCH v5 07/11] arm-cci: Add routines to save/restore all counters

On Mon, Jan 04, 2016 at 11:54:46AM +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 <punit.agrawal@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
> ---
>  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 a3938ef..2f1fcf0 100644
> --- a/drivers/bus/arm-cci.c
> +++ b/drivers/bus/arm-cci.c
> @@ -672,6 +672,44 @@ static void pmu_set_event(struct cci_pmu *cci_pmu, int idx, unsigned long event)
>  }
>  
>  /*
> + * 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 by the caller.

We should probably state "initialised to zero", or "empty".

> + */
> +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_disable_counters().
> + * For each counter set in the mask, enable the counter back.
> + */

Shouldn't that say pmu_save_counters?

With that:

Acked-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> +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
> 

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