diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/perf/hisilicon/hisi_pcie_pmu.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/perf/hisilicon/hisi_pcie_pmu.c b/drivers/perf/hisilicon/hisi_pcie_pmu.c index f06027574a24..fba569a8640c 100644 --- a/drivers/perf/hisilicon/hisi_pcie_pmu.c +++ b/drivers/perf/hisilicon/hisi_pcie_pmu.c @@ -452,10 +452,24 @@ static void hisi_pcie_pmu_set_period(struct perf_event *event) struct hisi_pcie_pmu *pcie_pmu = to_pcie_pmu(event->pmu); struct hw_perf_event *hwc = &event->hw; int idx = hwc->idx; + u64 orig_cnt, cnt; + + orig_cnt = hisi_pcie_pmu_read_counter(event); local64_set(&hwc->prev_count, HISI_PCIE_INIT_VAL); hisi_pcie_pmu_writeq(pcie_pmu, HISI_PCIE_CNT, idx, HISI_PCIE_INIT_VAL); hisi_pcie_pmu_writeq(pcie_pmu, HISI_PCIE_EXT_CNT, idx, HISI_PCIE_INIT_VAL); + + /* + * The counter maybe unwritable if the target event is unsupported. + * Check this by comparing the counts after setting the period. If + * the counts stay unchanged after setting the period then update + * the hwc->prev_count correctly. Otherwise the final counts user + * get maybe totally wrong. + */ + cnt = hisi_pcie_pmu_read_counter(event); + if (orig_cnt == cnt) + local64_set(&hwc->prev_count, cnt); } static void hisi_pcie_pmu_enable_counter(struct hisi_pcie_pmu *pcie_pmu, struct hw_perf_event *hwc) |