From: Rohan G Thomas <rohan.g.thomas@altera.com>

Drop those frames causing HLBS error to avoid HLBS interrupt
flooding and netdev watchdog timeouts due to blocked packets.
Also add HLBS frame drops to taprio stats.

Signed-off-by: Rohan G Thomas <rohan.g.thomas@altera.com>
Reviewed-by: Matthew Gerlach <matthew.gerlach@altera.com>
---
 drivers/net/ethernet/stmicro/stmmac/common.h     | 1 +
 drivers/net/ethernet/stmicro/stmmac/stmmac_est.c | 7 ++++++-
 drivers/net/ethernet/stmicro/stmmac/stmmac_est.h | 1 +
 drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c  | 7 +++++--
 4 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
index eaa1f2e1c5a53b297b014a8218bf8f3db5beb4de..8f34c9ad457f07553206841223fd38e55208d5ab 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 ac6f2e3a3fcd2f9ae21913845282ff015cd2f7ec..385431a3336b731547df49621098586b741cae85 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 +109,11 @@ 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);
 
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_est.h b/drivers/net/ethernet/stmicro/stmmac/stmmac_est.h
index d247fa383a6e44a5a8371dd491eab5b1c99cd1f2..f70221c9c84afe6bce62782c7847a8005e469dd7 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 694d6ee1438197bd4434af6e9b78f022e94ff98f..97e89a604abd7a01bb8e904c38f10716e0a911c1 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
@@ -1080,6 +1080,7 @@ static int tc_taprio_configure(struct stmmac_priv *priv,
 		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;

---
base-commit: 1f24a240974589ce42f70502ccb3ff3f5189d69a
change-id: 20250911-hlbs_2-5fdd5e483f02

Best regards,
-- 
Rohan G Thomas <rohan.g.thomas@altera.com>

On Thu, Sep 11, 2025 at 04:38:16PM +0800, Rohan G Thomas via B4 Relay wrote:
> @@ -109,6 +109,11 @@ 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]++;
> +		}

There's no need for the parens around the for loop.

I'm afraid I can't provide much more of a review as I don't have the
documentation for GMAC4 or XGMAC.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!

Hi Russell,

Thanks for reviewing the patch.

On 9/11/2025 6:21 PM, Russell King (Oracle) wrote:
> On Thu, Sep 11, 2025 at 04:38:16PM +0800, Rohan G Thomas via B4 Relay wrote:
>> @@ -109,6 +109,11 @@ 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]++;
>> +		}
> 
> There's no need for the parens around the for loop.

Sure, will fix this in the next version.

> 
> I'm afraid I can't provide much more of a review as I don't have the
> documentation for GMAC4 or XGMAC.

Understood, thanks for taking a look regardless.

> 
Best Regards,
Rohan