From: Robin Murphy robin.murphy@arm.com
[ Upstream commit 71746c995cac92fcf6a65661b51211cf2009d7f0 ]
It turns out that my naive DTC reset logic fails to work as intended, since, after checking with the hardware designers, the PMU actually needs to be fully enabled in order to correctly clear any pending overflows. Therefore, invert the sequence to start with turning on both enables so that we can reliably get the DTCs into a known state, then moving to our normal counters-stopped state from there. Since all the DTM counters have already been unpaired during the initial discovery pass, we just need to additionally reset the cycle counters to ensure that no other unexpected overflows occur during this period.
Fixes: 0ba64770a2f2 ("perf: Add Arm CMN-600 PMU driver") Reported-by: Geoff Blake blakgeof@amazon.com Signed-off-by: Robin Murphy robin.murphy@arm.com Link: https://lore.kernel.org/r/0ea4559261ea394f827c9aee5168c77a60aaee03.168494638... Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/perf/arm-cmn.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c index ff86075edca48..90008e24d1cc7 100644 --- a/drivers/perf/arm-cmn.c +++ b/drivers/perf/arm-cmn.c @@ -1898,9 +1898,10 @@ static int arm_cmn_init_dtc(struct arm_cmn *cmn, struct arm_cmn_node *dn, int id if (dtc->irq < 0) return dtc->irq;
- writel_relaxed(0, dtc->base + CMN_DT_PMCR); + writel_relaxed(CMN_DT_DTC_CTL_DT_EN, dtc->base + CMN_DT_DTC_CTL); + writel_relaxed(CMN_DT_PMCR_PMU_EN | CMN_DT_PMCR_OVFL_INTR_EN, dtc->base + CMN_DT_PMCR); + writeq_relaxed(0, dtc->base + CMN_DT_PMCCNTR); writel_relaxed(0x1ff, dtc->base + CMN_DT_PMOVSR_CLR); - writel_relaxed(CMN_DT_PMCR_OVFL_INTR_EN, dtc->base + CMN_DT_PMCR);
return 0; } @@ -1960,7 +1961,7 @@ static int arm_cmn_init_dtcs(struct arm_cmn *cmn) dn->type = CMN_TYPE_CCLA; }
- writel_relaxed(CMN_DT_DTC_CTL_DT_EN, cmn->dtc[0].base + CMN_DT_DTC_CTL); + arm_cmn_set_state(cmn, CMN_STATE_DISABLED);
return 0; }