arm-cci: Add helper to enable PMU without synchornising counters

On CCI-500 writing to a counter requires turning the PMU on. So,
synchronising the counter state should not be performed for such special cases,
while turning the PMU on. This patch adds a helper, __cci_pmu_enable_nosync(),
without flushing the counter states.

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>

diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
index 7ce7da0..bcc4c59 100644 (file)
--- a/drivers/bus/arm-cci.c
+++ b/drivers/bus/arm-cci.c
@@ -640,17 +640,22 @@ void cci_pmu_sync_counters(struct cci_pmu *cci_pmu)
 }
 
 /* Should be called with cci_pmu->hw_events->pmu_lock held */
-static void __cci_pmu_enable(struct cci_pmu *cci_pmu)
+static void __cci_pmu_enable_nosync(struct cci_pmu *cci_pmu)
 {
        u32 val;
 
-       cci_pmu_sync_counters(cci_pmu);
-
        /* Enable all the PMU counters. */
        val = readl_relaxed(cci_ctrl_base + CCI_PMCR) | CCI_PMCR_CEN;
        writel(val, cci_ctrl_base + CCI_PMCR);
 }
 
+/* Should be called with cci_pmu->hw_events->pmu_lock held */
+static void __cci_pmu_enable_sync(struct cci_pmu *cci_pmu)
+{
+       cci_pmu_sync_counters(cci_pmu);
+       __cci_pmu_enable_nosync(cci_pmu);
+}
+
 /* Should be called with cci_pmu->hw_events->pmu_lock held */
 static void __cci_pmu_disable(void)
 {
@@ -960,7 +965,7 @@ static irqreturn_t pmu_handle_irq(int irq_num, void *dev)
        }
 
        /* Enable the PMU and sync possibly overflowed counters */
-       __cci_pmu_enable(cci_pmu);
+       __cci_pmu_enable_sync(cci_pmu);
        raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
 
        return IRQ_RETVAL(handled);
@@ -1004,7 +1009,7 @@ static void cci_pmu_enable(struct pmu *pmu)
                return;
 
        raw_spin_lock_irqsave(&hw_events->pmu_lock, flags);
-       __cci_pmu_enable(cci_pmu);
+       __cci_pmu_enable_sync(cci_pmu);
        raw_spin_unlock_irqrestore(&hw_events->pmu_lock, flags);
 
 }