[PATCH V2 1/3] lib: sbi_pmu: ensure update hpm counter before starting counting

[Inochi Amaoto]

When detecting features of PMU, the hpm counter may be written to some
value, this will cause some unexpected behavior in some cases. So ensure
the hpm counter is updated before starting the counter and the related
interrupt.

Signed-off-by: Haijiao Liu <haijiao.liu at sophgo.com>
Co-authored-by: Inochi Amaoto <inochiama at outlook.com>
Signed-off-by: Inochi Amaoto <inochiama at outlook.com>
---
 lib/sbi/sbi_pmu.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/lib/sbi/sbi_pmu.c b/lib/sbi/sbi_pmu.c
index adb9f18..2904903 100644
--- a/lib/sbi/sbi_pmu.c
+++ b/lib/sbi/sbi_pmu.c
@@ -353,8 +353,11 @@ static int pmu_ctr_start_hw(uint32_t cidx, uint64_t ival, bool ival_update)
 	if (cidx >= num_hw_ctrs || cidx == 1)
 		return SBI_EINVAL;

-	if (sbi_hart_priv_version(scratch) < SBI_HART_PRIV_VER_1_11)
-		goto skip_inhibit_update;
+	if (sbi_hart_priv_version(scratch) < SBI_HART_PRIV_VER_1_11) {
+		if (ival_update)
+			pmu_ctr_write_hw(cidx, ival);
+		return 0;
+	}

 	/*
 	 * Some of the hardware may not support mcountinhibit but perf stat
@@ -368,14 +371,13 @@ static int pmu_ctr_start_hw(uint32_t cidx, uint64_t ival, bool ival_update)

 	if (sbi_hart_has_extension(scratch, SBI_HART_EXT_SSCOFPMF))
 		pmu_ctr_enable_irq_hw(cidx);
+	if (ival_update)
+		pmu_ctr_write_hw(cidx, ival);
 	if (pmu_dev && pmu_dev->hw_counter_enable_irq)
 		pmu_dev->hw_counter_enable_irq(cidx);
+
 	csr_write(CSR_MCOUNTINHIBIT, mctr_inhbt);

-skip_inhibit_update:
-	if (ival_update)
-		pmu_ctr_write_hw(cidx, ival);
-
 	return 0;
 }

--
2.41.0