diff mbox series

[net,2/2] net: stmmac: fix taprio configuration when base_time is in the past

Message ID 20210112172457.20539-2-yannick.vignon@oss.nxp.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [net,1/2] net: stmmac: fix taprio schedule configuration | expand

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netdev/cc_maintainers warning 3 maintainers not CCed: linux-stm32@st-md-mailman.stormreply.com mcoquelin.stm32@gmail.com linux-arm-kernel@lists.infradead.org
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Commit Message

Yannick Vignon Jan. 12, 2021, 5:24 p.m. UTC 
From: Yannick Vignon <yannick.vignon@nxp.com>

The Synopsys TSN MAC supports Qbv base times in the past, but only up to a
certain limit. As a result, a taprio qdisc configuration with a small
base time (for example when treating the base time as a simple phase
offset) is not applied by the hardware and silently ignored.

This was observed on an NXP i.MX8MPlus device, but likely affects all
TSN-variants of the MAC.

Fix the issue by making sure the base time is in the future, pushing it by
an integer amount of cycle times if needed. (a similar check is already
done in several other taprio implementations, see for example
drivers/net/ethernet/intel/igc/igc_tsn.c#L116 or
drivers/net/dsa/sja1105/sja1105_ptp.h#L39).

Signed-off-by: Yannick Vignon <yannick.vignon@nxp.com>
---
 .../net/ethernet/stmicro/stmmac/stmmac_tc.c   | 20 +++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
index f5bed4d26e80..f3543ec8ef10 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
@@ -599,8 +599,9 @@  static int tc_setup_taprio(struct stmmac_priv *priv,
 {
 	u32 size, wid = priv->dma_cap.estwid, dep = priv->dma_cap.estdep;
 	struct plat_stmmacenet_data *plat = priv->plat;
-	struct timespec64 time;
+	struct timespec64 time, current_time;
 	bool fpe = false;
+	ktime_t current_time_ns;
 	int i, ret = 0;
 	u64 ctr;
 
@@ -694,7 +695,22 @@  static int tc_setup_taprio(struct stmmac_priv *priv,
 	}
 
 	/* Adjust for real system time */
-	time = ktime_to_timespec64(qopt->base_time);
+	priv->ptp_clock_ops.gettime64(&priv->ptp_clock_ops, &current_time);
+	current_time_ns = timespec64_to_ktime(current_time);
+	if (ktime_after(qopt->base_time, current_time_ns)) {
+		time = ktime_to_timespec64(qopt->base_time);
+	} else {
+		s64 n;
+		ktime_t base_time;
+
+		n = div64_s64(ktime_sub_ns(current_time_ns, qopt->base_time),
+			      qopt->cycle_time);
+		base_time = ktime_add_ns(qopt->base_time,
+					 (n + 1) * qopt->cycle_time);
+
+		time = ktime_to_timespec64(base_time);
+	}
+
 	priv->plat->est->btr[0] = (u32)time.tv_nsec;
 	priv->plat->est->btr[1] = (u32)time.tv_sec;