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authorRobin Murphy <robin.murphy@arm.com>2022-12-05 19:46:13 +0000
committerWill Deacon <will@kernel.org>2023-01-19 18:30:21 +0000
commitbb21ef19a3d8f586a99310116d40622fb5b79942 (patch)
tree60c274adf7220640a62bd13c1d12d66ed8789437 /drivers/perf
parente126f6f42f89baee09e088ab6bc48f83ac3a0eae (diff)
perf/arm-cmn: Reset DTM_PMU_CONFIG at probe
Although we treat the DTM counters as free-running such that we're not too concerned about the initial DTM state, it's possible for a previous user to have left DTM counters enabled and paired with DTC counters. Thus if the first events are scheduled using some, but not all, DTMs, the as-yet-unused ones could end up adding spurious increments to the event counts at the DTC. Make sure we sync our initial DTM_PMU_CONFIG state to all the DTMs at probe time to avoid that possibility. Signed-off-by: Robin Murphy <robin.murphy@arm.com> Link: https://lore.kernel.org/r/ba5f38b3dc733cd06bfb5e659b697e76d18c2183.1670269572.git.robin.murphy@arm.com Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'drivers/perf')
-rw-r--r--drivers/perf/arm-cmn.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
index b80a9b74662b..e220714954b0 100644
--- a/drivers/perf/arm-cmn.c
+++ b/drivers/perf/arm-cmn.c
@@ -1865,6 +1865,7 @@ static void arm_cmn_init_dtm(struct arm_cmn_dtm *dtm, struct arm_cmn_node *xp, i
dtm->base = xp->pmu_base + CMN_DTM_OFFSET(idx);
dtm->pmu_config_low = CMN_DTM_PMU_CONFIG_PMU_EN;
+ writeq_relaxed(dtm->pmu_config_low, dtm->base + CMN_DTM_PMU_CONFIG);
for (i = 0; i < 4; i++) {
dtm->wp_event[i] = -1;
writeq_relaxed(0, dtm->base + CMN_DTM_WPn_MASK(i));