linux-kernel - [PATCH v6 1/4] perf: arm_cspmu: Split 64-bit write to 32-bit writes

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Date:   Mon, 14 Aug 2023 23:35:23 -0700
From:   Ilkka Koskinen <ilkka@...amperecomputing.com>
To:     Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>,
        Besar Wicaksono <bwicaksono@...dia.com>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Mark Rutland <mark.rutland@....com>,
        Jonathan Corbet <corbet@....net>
Cc:     Ilkka Koskinen <ilkka@...amperecomputing.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-doc@...r.kernel.org
Subject: [PATCH v6 1/4] perf: arm_cspmu: Split 64-bit write to 32-bit writes

Split the 64-bit register accesses if 64-bit access is not supported
by the PMU.

Signed-off-by: Ilkka Koskinen <ilkka@...amperecomputing.com>
Reviewed-by: Besar Wicaksono <bwicaksono@...dia.com>
---
 drivers/perf/arm_cspmu/arm_cspmu.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/perf/arm_cspmu/arm_cspmu.c b/drivers/perf/arm_cspmu/arm_cspmu.c
index 04be94b4aa48..6387cbad7a7d 100644
--- a/drivers/perf/arm_cspmu/arm_cspmu.c
+++ b/drivers/perf/arm_cspmu/arm_cspmu.c
@@ -715,7 +715,10 @@ static void arm_cspmu_write_counter(struct perf_event *event, u64 val)
 	if (use_64b_counter_reg(cspmu)) {
 		offset = counter_offset(sizeof(u64), event->hw.idx);
 
-		writeq(val, cspmu->base1 + offset);
+		if (cspmu->has_atomic_dword)
+			writeq(val, cspmu->base1 + offset);
+		else
+			lo_hi_writeq(val, cspmu->base1 + offset);
 	} else {
 		offset = counter_offset(sizeof(u32), event->hw.idx);
 
-- 
2.41.0