Merge branch 'net-stmmac-drop-frames-causing-hlbs-error'

Rohan G Thomas says:

====================
net: stmmac: Drop frames causing HLBS error

This patchset consists of following patchset to avoid netdev watchdog
reset due to Head-of-Line Blocking due to EST scheduling error.
 1. Drop those frames causing HLBS error
 2. Add HLBS frame drops to taprio stats

v2: https://lore.kernel.org/r/20250915-hlbs_2-v2-1-27266b2afdd9@altera.com
====================

Link: https://patch.msgid.link/20250925-hlbs_2-v3-0-3b39472776c2@altera.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

4 files changed, 13 insertions, 5 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
index eaa1f2e1c5a5..8f34c9ad457f 100644
--- a/drivers/net/ethernet/stmicro/stmmac/common.h
+++ b/drivers/net/ethernet/stmicro/stmmac/common.h
@@ -228,6 +228,7 @@ struct stmmac_extra_stats {
 	unsigned long mtl_est_btrlm;
 	unsigned long max_sdu_txq_drop[MTL_MAX_TX_QUEUES];
 	unsigned long mtl_est_txq_hlbf[MTL_MAX_TX_QUEUES];
+	unsigned long mtl_est_txq_hlbs[MTL_MAX_TX_QUEUES];
 	/* per queue statistics */
 	struct stmmac_txq_stats txq_stats[MTL_MAX_TX_QUEUES];
 	struct stmmac_rxq_stats rxq_stats[MTL_MAX_RX_QUEUES];
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_est.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_est.c
index ac6f2e3a3fcd..4b513d27a988 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_est.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_est.c
@@ -63,7 +63,7 @@ static int est_configure(struct stmmac_priv *priv, struct stmmac_est *cfg,
 			 EST_GMAC5_PTOV_SHIFT;
 	}
 	if (cfg->enable)
-		ctrl |= EST_EEST | EST_SSWL;
+		ctrl |= EST_EEST | EST_SSWL | EST_DFBS;
 	else
 		ctrl &= ~EST_EEST;
 
@@ -109,6 +109,10 @@ static void est_irq_status(struct stmmac_priv *priv, struct net_device *dev,
 
 		x->mtl_est_hlbs++;
 
+		for (i = 0; i < txqcnt; i++)
+			if (value & BIT(i))
+				x->mtl_est_txq_hlbs[i]++;
+
 		/* Clear Interrupt */
 		writel(value, est_addr + EST_SCH_ERR);
 
@@ -131,10 +135,9 @@ static void est_irq_status(struct stmmac_priv *priv, struct net_device *dev,
 
 		x->mtl_est_hlbf++;
 
-		for (i = 0; i < txqcnt; i++) {
+		for (i = 0; i < txqcnt; i++)
 			if (feqn & BIT(i))
 				x->mtl_est_txq_hlbf[i]++;
-		}
 
 		/* Clear Interrupt */
 		writel(feqn, est_addr + EST_FRM_SZ_ERR);
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_est.h b/drivers/net/ethernet/stmicro/stmmac/stmmac_est.h
index d247fa383a6e..f70221c9c84a 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_est.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_est.h
@@ -16,6 +16,7 @@
 #define EST_XGMAC_PTOV_MUL		9
 #define EST_SSWL			BIT(1)
 #define EST_EEST			BIT(0)
+#define EST_DFBS			BIT(5)
 
 #define EST_STATUS			0x00000008
 #define EST_GMAC5_BTRL			GENMASK(11, 8)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
index 694d6ee14381..97e89a604abd 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
@@ -1080,6 +1080,7 @@ disable:
 		for (i = 0; i < priv->plat->tx_queues_to_use; i++) {
 			priv->xstats.max_sdu_txq_drop[i] = 0;
 			priv->xstats.mtl_est_txq_hlbf[i] = 0;
+			priv->xstats.mtl_est_txq_hlbs[i] = 0;
 		}
 		mutex_unlock(&priv->est_lock);
 	}
@@ -1097,7 +1098,8 @@ static void tc_taprio_stats(struct stmmac_priv *priv,
 
 	for (i = 0; i < priv->plat->tx_queues_to_use; i++)
 		window_drops += priv->xstats.max_sdu_txq_drop[i] +
-				priv->xstats.mtl_est_txq_hlbf[i];
+				priv->xstats.mtl_est_txq_hlbf[i] +
+				priv->xstats.mtl_est_txq_hlbs[i];
 	qopt->stats.window_drops = window_drops;
 
 	/* Transmission overrun doesn't happen for stmmac, hence always 0 */
@@ -1111,7 +1113,8 @@ static void tc_taprio_queue_stats(struct stmmac_priv *priv,
 	int queue = qopt->queue_stats.queue;
 
 	q_stats->stats.window_drops = priv->xstats.max_sdu_txq_drop[queue] +
-				      priv->xstats.mtl_est_txq_hlbf[queue];
+				      priv->xstats.mtl_est_txq_hlbf[queue] +
+				      priv->xstats.mtl_est_txq_hlbs[queue];
 
 	/* Transmission overrun doesn't happen for stmmac, hence always 0 */
 	q_stats->stats.tx_overruns = 0;