linux-kernel - [PATCH v6 02/12] arm-cci: Group writes to counter

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Message-Id: <1453720877-24962-3-git-send-email-suzuki.poulose@arm.com>
Date:	Mon, 25 Jan 2016 11:21:07 +0000
From:	"Suzuki K. Poulose" <suzuki.poulose@....com>
To:	linux-arm-kernel@...ts.infradead.org
Cc:	mark.rutland@....com, punit.agrawal@....com, arm@...nel.org,
	linux-kernel@...r.kernel.org,
	"Suzuki K. Poulose" <suzuki.poulose@....com>
Subject: [PATCH v6 02/12] arm-cci: Group writes to counter

Add a helper to group the writes to PMU counter, this will be
used to delay setting the event period to pmu::pmu_enable()

Cc: Mark Rutland <mark.rutland@....com>
Cc: Punit Agrawal <punit.agrawal@....com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@....com>
---
Changes since V5:
  - Use the prev_count from event->hw for the counter value, than
    using a single value for all the counters.
---
 drivers/bus/arm-cci.c |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
index ee47e6b..936fa9b 100644
--- a/drivers/bus/arm-cci.c
+++ b/drivers/bus/arm-cci.c
@@ -771,6 +771,21 @@ static void pmu_write_counter(struct perf_event *event, u32 value)
 		pmu_write_register(cci_pmu, value, idx, CCI_PMU_CNTR);
 }
 
+static void __maybe_unused
+pmu_write_counters(struct cci_pmu *cci_pmu, unsigned long *mask)
+{
+	int i;
+	struct cci_pmu_hw_events *cci_hw = &cci_pmu->hw_events;
+
+	for_each_set_bit(i, mask, cci_pmu->num_cntrs) {
+		struct perf_event *event = cci_hw->events[i];
+
+		if (WARN_ON(!event))
+			continue;
+		pmu_write_counter(event, (u32)local64_read(&event->hw.prev_count));
+	}
+}
+
 static u64 pmu_event_update(struct perf_event *event)
 {
 	struct hw_perf_event *hwc = &event->hw;
-- 
1.7.9.5