[PATCH net-next] net: stmmac: add tc-ets qdisc offload

[PATCH net-next] net: stmmac: add tc-ets qdisc offload

[Lorenzo Bianconi]

Implement offload of the tc-ets qdisc in the stmmac driver. The number
of ETS bands cannot exceed the number of TX queues, and mixing strict
priority bands (zero quanta) with weighted bands is rejected.

When all bands are strict priority, the MTL scheduler is programmed with
SP scheduling; otherwise the requested weights are applied to the TX
queues and the scheduler is switched to DWRR. The TC_ETS_STATS command
is accepted and handled.

Export stmmac_set_tx_queue_weight() so the ETS path can reprogram queue
weights, and wire TC_SETUP_QDISC_ETS into stmmac_setup_tc().

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
---
 drivers/net/ethernet/stmicro/stmmac/hwif.h        |  4 ++
 drivers/net/ethernet/stmicro/stmmac/stmmac.h      |  1 +
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |  4 +-
 drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c   | 69 +++++++++++++++++++++++
 4 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/hwif.h b/drivers/net/ethernet/stmicro/stmmac/hwif.h
index 04dafec021b4..b70883a53b09 100644
--- a/drivers/net/ethernet/stmicro/stmmac/hwif.h
+++ b/drivers/net/ethernet/stmicro/stmmac/hwif.h
@@ -580,6 +580,8 @@ struct stmmac_tc_ops {
 			    struct tc_taprio_qopt_offload *qopt);
 	int (*setup_etf)(struct stmmac_priv *priv,
 			 struct tc_etf_qopt_offload *qopt);
+	int (*setup_ets)(struct stmmac_priv *priv,
+			 struct tc_ets_qopt_offload *qopt);
 	int (*query_caps)(struct stmmac_priv *priv,
 			  struct tc_query_caps_base *base);
 	int (*setup_mqprio)(struct stmmac_priv *priv,
@@ -598,6 +600,8 @@ struct stmmac_tc_ops {
 	stmmac_do_callback(__priv, tc, setup_taprio, __args)
 #define stmmac_tc_setup_etf(__priv, __args...) \
 	stmmac_do_callback(__priv, tc, setup_etf, __args)
+#define stmmac_tc_setup_ets(__priv, __args...) \
+	stmmac_do_callback(__priv, tc, setup_ets, __args)
 #define stmmac_tc_query_caps(__priv, __args...) \
 	stmmac_do_callback(__priv, tc, query_caps, __args)
 #define stmmac_tc_setup_mqprio(__priv, __args...) \
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index 8ba8f03e1ce0..8ea6dd0c1697 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -394,6 +394,7 @@ enum stmmac_state {
 
 extern const struct dev_pm_ops stmmac_simple_pm_ops;
 
+void stmmac_set_tx_queue_weight(struct stmmac_priv *priv);
 int stmmac_mdio_unregister(struct net_device *ndev);
 int stmmac_mdio_register(struct net_device *ndev);
 int stmmac_mdio_reset(struct mii_bus *mii);
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 79b71466d5b0..404f4132f223 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -3419,7 +3419,7 @@ static void stmmac_set_rings_length(struct stmmac_priv *priv)
  *  @priv: driver private structure
  *  Description: It is used for setting TX queues weight
  */
-static void stmmac_set_tx_queue_weight(struct stmmac_priv *priv)
+void stmmac_set_tx_queue_weight(struct stmmac_priv *priv)
 {
 	u8 tx_queues_count = priv->plat->tx_queues_to_use;
 	u32 weight;
@@ -6424,6 +6424,8 @@ static int stmmac_setup_tc(struct net_device *ndev, enum tc_setup_type type,
 		return stmmac_tc_setup_taprio(priv, priv, type_data);
 	case TC_SETUP_QDISC_ETF:
 		return stmmac_tc_setup_etf(priv, priv, type_data);
+	case TC_SETUP_QDISC_ETS:
+		return stmmac_tc_setup_ets(priv, priv, type_data);
 	default:
 		return -EOPNOTSUPP;
 	}
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
index 14cabe76e53e..17be37e43bf8 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
@@ -1210,6 +1210,73 @@ static int tc_setup_etf(struct stmmac_priv *priv,
 	return 0;
 }
 
+static int tc_setup_sp_sched(struct stmmac_priv *priv)
+{
+	struct plat_stmmacenet_data *pdata = priv->plat;
+	int i;
+
+	for (i = 0; i < pdata->tx_queues_to_use; i++)
+		pdata->tx_queues_cfg[i].weight = 0;
+	stmmac_set_tx_queue_weight(priv);
+
+	pdata->tx_sched_algorithm = MTL_TX_ALGORITHM_SP;
+	stmmac_prog_mtl_tx_algorithms(priv, priv->hw,
+				      pdata->tx_sched_algorithm);
+
+	return 0;
+}
+
+static int tc_setup_ets_sched(struct stmmac_priv *priv,
+			      struct tc_ets_qopt_offload *qopt)
+{
+	struct tc_ets_qopt_offload_replace_params *p = &qopt->replace_params;
+	struct plat_stmmacenet_data *pdata = priv->plat;
+	int i, nstrict = 0;
+
+	if (p->bands > priv->plat->tx_queues_to_use)
+		return -EOPNOTSUPP;
+
+	for (i = 0; i < p->bands; i++) {
+		if (!p->quanta[i])
+			nstrict++;
+	}
+
+	if (p->bands && nstrict)
+		return -EOPNOTSUPP;
+
+	if (nstrict) {
+		tc_setup_sp_sched(priv);
+	} else {
+		for (i = 0; i < pdata->tx_queues_to_use; i++) {
+			if (i < p->bands)
+				pdata->tx_queues_cfg[i].weight = p->weights[i];
+			else
+				pdata->tx_queues_cfg[i].weight = 0;
+		}
+		stmmac_set_tx_queue_weight(priv);
+		pdata->tx_sched_algorithm = MTL_TX_ALGORITHM_DWRR;
+		stmmac_prog_mtl_tx_algorithms(priv, priv->hw,
+					      pdata->tx_sched_algorithm);
+	}
+
+	return 0;
+}
+
+static int tc_setup_ets(struct stmmac_priv *priv,
+			struct tc_ets_qopt_offload *qopt)
+{
+	switch (qopt->command) {
+	case TC_ETS_REPLACE:
+		return tc_setup_ets_sched(priv, qopt);
+	case TC_ETS_DESTROY:
+		return tc_setup_sp_sched(priv);
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
 static int tc_query_caps(struct stmmac_priv *priv,
 			 struct tc_query_caps_base *base)
 {
@@ -1308,6 +1375,7 @@ const struct stmmac_tc_ops dwmac4_tc_ops = {
 	.setup_cls = tc_setup_cls,
 	.setup_taprio = tc_setup_taprio_without_fpe,
 	.setup_etf = tc_setup_etf,
+	.setup_ets = tc_setup_ets,
 	.query_caps = tc_query_caps,
 	.setup_mqprio = tc_setup_mqprio_unimplemented,
 };
@@ -1319,6 +1387,7 @@ const struct stmmac_tc_ops dwmac510_tc_ops = {
 	.setup_cls = tc_setup_cls,
 	.setup_taprio = tc_setup_taprio,
 	.setup_etf = tc_setup_etf,
+	.setup_ets = tc_setup_ets,
 	.query_caps = tc_query_caps,
 	.setup_mqprio = tc_setup_dwmac510_mqprio,
 };

---
base-commit: 828c4a5a9518117f9f7bdc445a7eeca85fc91bf8
change-id: 20260804-stmmac-ets-offload-cc936c99fdb1

Best regards,
-- 
Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>

Re: [PATCH net-next] net: stmmac: add tc-ets qdisc offload

[Maxime Chevallier]

Hi Lorenzo,

On 8/4/26 20:17, Lorenzo Bianconi wrote:
> Implement offload of the tc-ets qdisc in the stmmac driver. The number
> of ETS bands cannot exceed the number of TX queues, and mixing strict
> priority bands (zero quanta) with weighted bands is rejected.
> 
> When all bands are strict priority, the MTL scheduler is programmed with
> SP scheduling; otherwise the requested weights are applied to the TX
> queues and the scheduler is switched to DWRR. The TC_ETS_STATS command
> is accepted and handled.
> 
> Export stmmac_set_tx_queue_weight() so the ETS path can reprogram queue
> weights, and wire TC_SETUP_QDISC_ETS into stmmac_setup_tc().
> 
> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>

From my very small understanding of ETS, this looks good to me.

Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>

Maxime

Re: [PATCH net-next] net: stmmac: add tc-ets qdisc offload

[Davide Caratti]

On Tue, Aug 04, 2026 at 08:17:35PM +0200, Lorenzo Bianconi wrote:

[...]
 
> When all bands are strict priority, the MTL scheduler is programmed with
> SP scheduling; otherwise the requested weights are applied to the TX
> queues and the scheduler is switched to DWRR. The TC_ETS_STATS command
> is accepted and handled.
> 
> Export stmmac_set_tx_queue_weight() so the ETS path can reprogram queue
> weights, and wire TC_SETUP_QDISC_ETS into stmmac_setup_tc().
> 
> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>

hello Lorenzo, thanks for your patch!

> ---
> +static int tc_setup_ets_sched(struct stmmac_priv *priv,
> +			      struct tc_ets_qopt_offload *qopt)
> +{
> +	struct tc_ets_qopt_offload_replace_params *p = &qopt->replace_params;
> +	struct plat_stmmacenet_data *pdata = priv->plat;
> +	int i, nstrict = 0;
> +
> +	if (p->bands > priv->plat->tx_queues_to_use)
> +		return -EOPNOTSUPP;
> +
> +	for (i = 0; i < p->bands; i++) {
> +		if (!p->quanta[i])
> +			nstrict++;
> +	}
> +
> +	if (p->bands && nstrict)
> +		return -EOPNOTSUPP;
> +
> +	if (nstrict) {
> +		tc_setup_sp_sched(priv);

From what I understood, this will fail configuring the strict priority case (the only one
possible according to the commit message, where all bands have quanta equal to 0). Maybe
the if() statement should be done like:

 if (nstrict && nstrict != p->bands)
	return -EOPNOTSUPP;

WDYT? thank you in advance!

-- 
davide

Re: [PATCH net-next] net: stmmac: add tc-ets qdisc offload

[Davide Caratti]

On Tue, Aug 04, 2026 at 08:17:35PM +0200, Lorenzo Bianconi wrote:

[...]

> When all bands are strict priority, the MTL scheduler is programmed with
> SP scheduling; 

... and I replied too early _ sorry for the noise _ there is another small thing
w.r.t. SP scheduling:

> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
> @@ -1210,6 +1210,73 @@ static int tc_setup_etf(struct stmmac_priv *priv,
>  	return 0;
>  }
>  
> +static int tc_setup_sp_sched(struct stmmac_priv *priv)
> +{
> +	struct plat_stmmacenet_data *pdata = priv->plat;
> +	int i;
> +
> +	for (i = 0; i < pdata->tx_queues_to_use; i++)
> +		pdata->tx_queues_cfg[i].weight = 0;
> +	stmmac_set_tx_queue_weight(priv);
> +
> +	pdata->tx_sched_algorithm = MTL_TX_ALGORITHM_SP;
> +	stmmac_prog_mtl_tx_algorithms(priv, priv->hw,
> +				      pdata->tx_sched_algorithm);
> +
> +	return 0;
> +}

The above function configures the stmmac SP queues to a well-known state where all
queues are SP. However,

[...]

> +
> +static int tc_setup_ets_sched(struct stmmac_priv *priv,
> +			      struct tc_ets_qopt_offload *qopt)
> +{
> +	struct tc_ets_qopt_offload_replace_params *p = &qopt->replace_params;
> +	struct plat_stmmacenet_data *pdata = priv->plat;
> +	int i, nstrict = 0;
> +
> +	if (p->bands > priv->plat->tx_queues_to_use)
> +		return -EOPNOTSUPP;
> +
> +	for (i = 0; i < p->bands; i++) {
> +		if (!p->quanta[i])
> +			nstrict++;
> +	}
> +
> +	if (p->bands && nstrict)
> +		return -EOPNOTSUPP;
> +
> +	if (nstrict) {
> +		tc_setup_sp_sched(priv);

This is not necessarily what the user wants when setting up the ETS qdisc.
The driver should parse 'priomap' (like in [1] or [2]) so that only 'nstrict'
queues are involved, and selected based on the packet priority. Otherwise, the
offloaded ETS is going to behave very differently from its full-software
implementation _ which is something we probably want to avoid.

[1] https://elixir.bootlin.com/linux/v7.1.5/source/drivers/net/ethernet/microchip/lan966x/lan966x_ets.c#L36
[2] https://elixir.bootlin.com/linux/v7.1.5/source/drivers/net/ethernet/airoha/airoha_eth.c#L2281
	
WDYT? Any feedback appreciated!

-- 
davide

Re: [PATCH net-next] net: stmmac: add tc-ets qdisc offload

[Lorenzo Bianconi]

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> On Tue, Aug 04, 2026 at 08:17:35PM +0200, Lorenzo Bianconi wrote:
> 
> [...]
>  
> > When all bands are strict priority, the MTL scheduler is programmed with
> > SP scheduling; otherwise the requested weights are applied to the TX
> > queues and the scheduler is switched to DWRR. The TC_ETS_STATS command
> > is accepted and handled.
> > 
> > Export stmmac_set_tx_queue_weight() so the ETS path can reprogram queue
> > weights, and wire TC_SETUP_QDISC_ETS into stmmac_setup_tc().
> > 
> > Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
> 
> hello Lorenzo, thanks for your patch!

Hi Davide,

> 
> > ---
> > +static int tc_setup_ets_sched(struct stmmac_priv *priv,
> > +			      struct tc_ets_qopt_offload *qopt)
> > +{
> > +	struct tc_ets_qopt_offload_replace_params *p = &qopt->replace_params;
> > +	struct plat_stmmacenet_data *pdata = priv->plat;
> > +	int i, nstrict = 0;
> > +
> > +	if (p->bands > priv->plat->tx_queues_to_use)
> > +		return -EOPNOTSUPP;
> > +
> > +	for (i = 0; i < p->bands; i++) {
> > +		if (!p->quanta[i])
> > +			nstrict++;
> > +	}
> > +
> > +	if (p->bands && nstrict)
> > +		return -EOPNOTSUPP;
> > +
> > +	if (nstrict) {
> > +		tc_setup_sp_sched(priv);
> 
> From what I understood, this will fail configuring the strict priority case (the only one
> possible according to the commit message, where all bands have quanta equal to 0). Maybe
> the if() statement should be done like:
> 
>  if (nstrict && nstrict != p->bands)
> 	return -EOPNOTSUPP;
> 
> WDYT? thank you in advance!

ack, I agree. I will fix it in v2.

Regards,
Lorenzo

> 
> -- 
> davide
> 

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Re: [PATCH net-next] net: stmmac: add tc-ets qdisc offload

[Lorenzo Bianconi]

[-- Attachment #1: Type: text/plain, Size: 2815 bytes --]

> On Tue, Aug 04, 2026 at 08:17:35PM +0200, Lorenzo Bianconi wrote:
> 
> [...]
> 
> > When all bands are strict priority, the MTL scheduler is programmed with
> > SP scheduling; 
> 
> ... and I replied too early _ sorry for the noise _ there is another small thing

thx for the review :)

> w.r.t. SP scheduling:
> 
> > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
> > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
> > @@ -1210,6 +1210,73 @@ static int tc_setup_etf(struct stmmac_priv *priv,
> >  	return 0;
> >  }
> >  
> > +static int tc_setup_sp_sched(struct stmmac_priv *priv)
> > +{
> > +	struct plat_stmmacenet_data *pdata = priv->plat;
> > +	int i;
> > +
> > +	for (i = 0; i < pdata->tx_queues_to_use; i++)
> > +		pdata->tx_queues_cfg[i].weight = 0;
> > +	stmmac_set_tx_queue_weight(priv);
> > +
> > +	pdata->tx_sched_algorithm = MTL_TX_ALGORITHM_SP;
> > +	stmmac_prog_mtl_tx_algorithms(priv, priv->hw,
> > +				      pdata->tx_sched_algorithm);
> > +
> > +	return 0;
> > +}
> 
> The above function configures the stmmac SP queues to a well-known state where all
> queues are SP. However,
> 
> [...]
> 
> > +
> > +static int tc_setup_ets_sched(struct stmmac_priv *priv,
> > +			      struct tc_ets_qopt_offload *qopt)
> > +{
> > +	struct tc_ets_qopt_offload_replace_params *p = &qopt->replace_params;
> > +	struct plat_stmmacenet_data *pdata = priv->plat;
> > +	int i, nstrict = 0;
> > +
> > +	if (p->bands > priv->plat->tx_queues_to_use)
> > +		return -EOPNOTSUPP;
> > +
> > +	for (i = 0; i < p->bands; i++) {
> > +		if (!p->quanta[i])
> > +			nstrict++;
> > +	}
> > +
> > +	if (p->bands && nstrict)
> > +		return -EOPNOTSUPP;
> > +
> > +	if (nstrict) {
> > +		tc_setup_sp_sched(priv);
> 
> This is not necessarily what the user wants when setting up the ETS qdisc.
> The driver should parse 'priomap' (like in [1] or [2]) so that only 'nstrict'
> queues are involved, and selected based on the packet priority. Otherwise, the
> offloaded ETS is going to behave very differently from its full-software
> implementation _ which is something we probably want to avoid.
> 
> [1] https://elixir.bootlin.com/linux/v7.1.5/source/drivers/net/ethernet/microchip/lan966x/lan966x_ets.c#L36
> [2] https://elixir.bootlin.com/linux/v7.1.5/source/drivers/net/ethernet/airoha/airoha_eth.c#L2281
> 	
> WDYT? Any feedback appreciated!

ack, I agree. Since the hw assigns increasing priority to the sp queues (prio_n+1 > prio_n),
we should check the priomap according to the following code:

	if (nstrict) {
		if (nstrict != p->bands)
			return -EINVAL;

		for (i = 0; i < p->bands; i++) {
			if (p->priomap[p->bands - i - 1] != i)
				return -EINVAL;
		}
		...
	}

Agree?

Regard,
Lorenzo

> 
> -- 
> davide
> 

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