[PATCH net-next v3 0/2] net: dsa: yt921x: Add port TBF support

[PATCH net-next v3 0/2] net: dsa: yt921x: Add port TBF support

[David Yang]

v2: https://lore.kernel.org/r/20260504101258.1608004-1-mmyangfl@gmail.com
  - drop changes on tc_tbf_qopt_offload_replace_params
  - drop excessive checks for tbf setup
  - react to TC_TBF_STATS correctly
v1: https://lore.kernel.org/r/20260502215314.917687-1-mmyangfl@gmail.com
  - remove queue related register definiations
  - add missing extack param during tbf setup
v0: https://lore.kernel.org/r/20260409171209.2575583-1-mmyangfl@gmail.com
  - picked from old series
  - add extack to the offload struct
  - add all params to the offload struct

David Yang (2):
  net/sched: tbf: add extack to offload params
  net: dsa: yt921x: Add port TBF support

 drivers/net/dsa/yt921x.c | 84 ++++++++++++++++++++++++++++++++++++++++
 drivers/net/dsa/yt921x.h | 18 +++++++++
 include/net/pkt_cls.h    |  1 +
 net/sched/sch_tbf.c      |  9 ++++-
 4 files changed, 110 insertions(+), 2 deletions(-)

-- 
2.53.0

[PATCH net-next v3 1/2] net/sched: tbf: add extack to offload params

[David Yang]

Drivers might have error messages to propagate to user space. Propagate
the netlink extack so that they can inform user space in a verbal way of
their limitations.

Signed-off-by: David Yang <mmyangfl@gmail.com>
---
 include/net/pkt_cls.h | 1 +
 net/sched/sch_tbf.c   | 9 +++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index 99ac747b7906..3bd08d7f39c1 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -1046,6 +1046,7 @@ struct tc_tbf_qopt_offload_replace_params {
 };
 
 struct tc_tbf_qopt_offload {
+	struct netlink_ext_ack *extack;
 	enum tc_tbf_command command;
 	u32 handle;
 	u32 parent;
diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index f2340164f579..4576111fe075 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -139,7 +139,8 @@ static u64 psched_ns_t2l(const struct psched_ratecfg *r,
 	return len;
 }
 
-static void tbf_offload_change(struct Qdisc *sch)
+static void tbf_offload_change(struct Qdisc *sch,
+			       struct netlink_ext_ack *extack)
 {
 	struct tbf_sched_data *q = qdisc_priv(sch);
 	struct net_device *dev = qdisc_dev(sch);
@@ -148,6 +149,7 @@ static void tbf_offload_change(struct Qdisc *sch)
 	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
 		return;
 
+	qopt.extack = extack;
 	qopt.command = TC_TBF_REPLACE;
 	qopt.handle = sch->handle;
 	qopt.parent = sch->parent;
@@ -166,6 +168,7 @@ static void tbf_offload_destroy(struct Qdisc *sch)
 	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
 		return;
 
+	qopt.extack = NULL;
 	qopt.command = TC_TBF_DESTROY;
 	qopt.handle = sch->handle;
 	qopt.parent = sch->parent;
@@ -176,6 +179,7 @@ static int tbf_offload_dump(struct Qdisc *sch)
 {
 	struct tc_tbf_qopt_offload qopt;
 
+	qopt.extack = NULL;
 	qopt.command = TC_TBF_STATS;
 	qopt.handle = sch->handle;
 	qopt.parent = sch->parent;
@@ -193,6 +197,7 @@ static void tbf_offload_graft(struct Qdisc *sch, struct Qdisc *new,
 		.parent		= sch->parent,
 		.child_handle	= new->handle,
 		.command	= TC_TBF_GRAFT,
+		.extack		= extack,
 	};
 
 	qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, old,
@@ -477,7 +482,7 @@ static int tbf_change(struct Qdisc *sch, struct nlattr *opt,
 	qdisc_put(old);
 	err = 0;
 
-	tbf_offload_change(sch);
+	tbf_offload_change(sch, extack);
 done:
 	return err;
 }
-- 
2.53.0

Re: [PATCH net-next v3 1/2] net/sched: tbf: add extack to offload params

[Simon Horman]

From: 'Simon Horman' <horms@kernel.org>

This is an AI-generated review of your patch. The human sending this
email has considered the AI review valid, or at least plausible.
Full review at: https://sashiko.dev
---
net/sched: tbf: add extack to offload params

Drivers might have error messages to propagate to user space. Propagate
the netlink extack so that they can inform user space in a verbal way of
their limitations.

> diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
> index f2340164f579a..4576111fe0758 100644
> --- a/net/sched/sch_tbf.c
> +++ b/net/sched/sch_tbf.c
[ ... ]
> @@ -193,6 +197,7 @@ static void tbf_offload_graft(struct Qdisc *sch, struct Qdisc *new,
>  		.parent		= sch->parent,
>  		.child_handle	= new->handle,
>  		.command	= TC_TBF_GRAFT,
> +		.extack		= extack,
>  	};
>  
>  	qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, old,

Will the driver's extack message be overwritten here?

Looking at qdisc_offload_graft_helper() in net/sched/sch_api.c, if the
driver returns an error and any qdisc is offloaded, it calls
NL_SET_ERR_MSG:

net/sched/sch_api.c:qdisc_offload_graft_helper() {
	err = dev->netdev_ops->ndo_setup_tc(dev, type, type_data);
	...
	if (any_qdisc_is_offloaded)
		NL_SET_ERR_MSG(extack, "Offloading graft operation failed.");
}

Does this unconditionally overwrite the specific error message just set
by the driver, defeating the patch's goal for graft operations?

[PATCH net-next v3 2/2] net: dsa: yt921x: Add port TBF support

[David Yang]

React to TC_SETUP_QDISC_TBF and configure the egress shaper as
appropriate with the maximum rate and burst size requested by the user.
Per queue shaper is possible, though not touched in this commit.

Signed-off-by: David Yang <mmyangfl@gmail.com>
---
 drivers/net/dsa/yt921x.c | 84 ++++++++++++++++++++++++++++++++++++++++
 drivers/net/dsa/yt921x.h | 18 +++++++++
 2 files changed, 102 insertions(+)

diff --git a/drivers/net/dsa/yt921x.c b/drivers/net/dsa/yt921x.c
index fd1fdcd5f9a3..e5f547629bfd 100644
--- a/drivers/net/dsa/yt921x.c
+++ b/drivers/net/dsa/yt921x.c
@@ -24,6 +24,7 @@
 #include <net/dsa.h>
 #include <net/dscp.h>
 #include <net/ieee8021q.h>
+#include <net/pkt_cls.h>
 
 #include "yt921x.h"
 
@@ -1272,6 +1273,17 @@ yt921x_marker_tfm_police(struct yt921x_marker *marker,
 				 priv, port, extack);
 }
 
+static int
+yt921x_marker_tfm_shape(struct yt921x_marker *marker, u64 rate, u64 burst,
+			unsigned int flags, struct yt921x_priv *priv, int port,
+			struct netlink_ext_ack *extack)
+{
+	return yt921x_marker_tfm(marker, rate, burst, flags,
+				 priv->port_shape_slot_ns, YT921X_SHAPE_CIR_MAX,
+				 YT921X_SHAPE_CBS_MAX, YT921X_SHAPE_UNIT_MAX,
+				 priv, port, extack);
+}
+
 static int
 yt921x_police_validate(const struct flow_action_police *police,
 		       const struct flow_action *action,
@@ -1378,6 +1390,70 @@ yt921x_dsa_port_policer_add(struct dsa_switch *ds, int port,
 	return res;
 }
 
+static int
+yt921x_dsa_port_setup_tc_tbf_port(struct dsa_switch *ds, int port,
+				  const struct tc_tbf_qopt_offload *qopt)
+{
+	struct yt921x_priv *priv = to_yt921x_priv(ds);
+	struct netlink_ext_ack *extack = qopt->extack;
+	u32 ctrls[2];
+	int res;
+
+	if (qopt->parent != TC_H_ROOT)
+		return -EOPNOTSUPP;
+
+	switch (qopt->command) {
+	case TC_TBF_STATS:
+		return 0;
+	case TC_TBF_DESTROY:
+		ctrls[0] = 0;
+		ctrls[1] = 0;
+		break;
+	case TC_TBF_REPLACE: {
+		const struct tc_tbf_qopt_offload_replace_params *p;
+		struct yt921x_marker marker;
+
+		p = &qopt->replace_params;
+
+		res = yt921x_marker_tfm_shape(&marker, p->rate.rate_bytes_ps,
+					      p->max_size,
+					      YT921X_MARKER_SINGLE_BUCKET,
+					      priv, port, extack);
+		if (res)
+			return res;
+
+		ctrls[0] = YT921X_PORT_SHAPE_CTRLa_CIR(marker.cir) |
+			   YT921X_PORT_SHAPE_CTRLa_CBS(marker.cbs);
+		ctrls[1] = YT921X_PORT_SHAPE_CTRLb_UNIT(marker.unit) |
+			   YT921X_PORT_SHAPE_CTRLb_EN;
+		break;
+	}
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	mutex_lock(&priv->reg_lock);
+	res = yt921x_reg64_write(priv, YT921X_PORTn_SHAPE_CTRL(port), ctrls);
+	mutex_unlock(&priv->reg_lock);
+
+	return res;
+}
+
+static int
+yt921x_dsa_port_setup_tc(struct dsa_switch *ds, int port,
+			 enum tc_setup_type type, void *type_data)
+{
+	switch (type) {
+	case TC_SETUP_QDISC_TBF: {
+		const struct tc_tbf_qopt_offload *qopt = type_data;
+
+		return yt921x_dsa_port_setup_tc_tbf_port(ds, port, qopt);
+	}
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
 static int
 yt921x_mirror_del(struct yt921x_priv *priv, int port, bool ingress)
 {
@@ -3524,6 +3600,13 @@ static int yt921x_chip_setup_tc(struct yt921x_priv *priv)
 		return res;
 	priv->meter_slot_ns = ctrl * op_ns;
 
+	ctrl = max(priv->port_shape_slot_ns / op_ns,
+		   YT921X_PORT_SHAPE_SLOT_MIN);
+	res = yt921x_reg_write(priv, YT921X_PORT_SHAPE_SLOT, ctrl);
+	if (res)
+		return res;
+	priv->port_shape_slot_ns = ctrl * op_ns;
+
 	return 0;
 }
 
@@ -3680,6 +3763,7 @@ static const struct dsa_switch_ops yt921x_dsa_switch_ops = {
 	/* rate */
 	.port_policer_del	= yt921x_dsa_port_policer_del,
 	.port_policer_add	= yt921x_dsa_port_policer_add,
+	.port_setup_tc		= yt921x_dsa_port_setup_tc,
 	/* hsr */
 	.port_hsr_leave		= dsa_port_simple_hsr_leave,
 	.port_hsr_join		= dsa_port_simple_hsr_join,
diff --git a/drivers/net/dsa/yt921x.h b/drivers/net/dsa/yt921x.h
index 546b12a8994a..70fa780c337f 100644
--- a/drivers/net/dsa/yt921x.h
+++ b/drivers/net/dsa/yt921x.h
@@ -531,6 +531,19 @@ enum yt921x_app_selector {
 #define  YT921X_MIRROR_PORT_M			GENMASK(3, 0)
 #define   YT921X_MIRROR_PORT(x)				FIELD_PREP(YT921X_MIRROR_PORT_M, (x))
 
+#define YT921X_PORT_SHAPE_SLOT		0x34000c
+#define  YT921X_PORT_SHAPE_SLOT_SLOT_M		GENMASK(11, 0)
+#define YT921X_PORTn_SHAPE_CTRL(port)	(0x354000 + 8 * (port))
+#define  YT921X_PORT_SHAPE_CTRLb_EN		BIT(4)
+#define  YT921X_PORT_SHAPE_CTRLb_PKT_MODE	BIT(3)	/* 0: byte rate mode */
+#define  YT921X_PORT_SHAPE_CTRLb_UNIT_M		GENMASK(2, 0)
+#define   YT921X_PORT_SHAPE_CTRLb_UNIT(x)		FIELD_PREP(YT921X_PORT_SHAPE_CTRLb_UNIT_M, (x))
+#define  YT921X_PORT_SHAPE_CTRLa_CBS_M		GENMASK(31, 18)
+#define   YT921X_PORT_SHAPE_CTRLa_CBS(x)		FIELD_PREP(YT921X_PORT_SHAPE_CTRLa_CBS_M, (x))
+#define  YT921X_PORT_SHAPE_CTRLa_CIR_M		GENMASK(17, 0)
+#define   YT921X_PORT_SHAPE_CTRLa_CIR(x)		FIELD_PREP(YT921X_PORT_SHAPE_CTRLa_CIR_M, (x))
+#define YT921X_PORTn_SHAPE_STAT(port)	(0x356000 + 4 * (port))
+
 #define YT921X_EDATA_EXTMODE	0xfb
 #define YT921X_EDATA_LEN	0x100
 
@@ -556,6 +569,10 @@ enum yt921x_fdb_entry_status {
 #define YT921X_METER_UNIT_MAX	((1 << 3) - 1)
 #define YT921X_METER_CIR_MAX	((1 << 18) - 1)
 #define YT921X_METER_CBS_MAX	((1 << 16) - 1)
+#define YT921X_PORT_SHAPE_SLOT_MIN	80
+#define YT921X_SHAPE_UNIT_MAX	((1 << 3) - 1)
+#define YT921X_SHAPE_CIR_MAX	((1 << 18) - 1)
+#define YT921X_SHAPE_CBS_MAX	((1 << 14) - 1)
 
 #define YT921X_LAG_NUM		2
 #define YT921X_LAG_PORT_NUM	4
@@ -652,6 +669,7 @@ struct yt921x_priv {
 
 	const struct yt921x_info *info;
 	unsigned int meter_slot_ns;
+	unsigned int port_shape_slot_ns;
 	/* cache of dsa_cpu_ports(ds) */
 	u16 cpu_ports_mask;
 	unsigned char cycle_ns;
-- 
2.53.0

Re: [PATCH net-next v3 2/2] net: dsa: yt921x: Add port TBF support

[Paolo Abeni]

On 5/8/26 8:57 AM, David Yang wrote:
> @@ -1378,6 +1390,70 @@ yt921x_dsa_port_policer_add(struct dsa_switch *ds, int port,
>  	return res;
>  }
>  
> +static int
> +yt921x_dsa_port_setup_tc_tbf_port(struct dsa_switch *ds, int port,
> +				  const struct tc_tbf_qopt_offload *qopt)
> +{
> +	struct yt921x_priv *priv = to_yt921x_priv(ds);
> +	struct netlink_ext_ack *extack = qopt->extack;
> +	u32 ctrls[2];
> +	int res;
> +
> +	if (qopt->parent != TC_H_ROOT)
> +		return -EOPNOTSUPP;
> +
> +	switch (qopt->command) {
> +	case TC_TBF_STATS:
> +		return 0;

The above makes the stats actually not supported; it should return
-NOPNOTSUPP.

/P

Re: [PATCH net-next v3 2/2] net: dsa: yt921x: Add port TBF support

[Simon Horman]

From: 'Simon Horman' <horms@kernel.org>

This is an AI-generated review of your patch. The human sending this
email has considered the AI review valid, or at least plausible.
Full review at: https://sashiko.dev
---
net: dsa: yt921x: Add port TBF support

This commit adds support for configuring the egress shaper via the
TC_SETUP_QDISC_TBF offload in the yt921x driver.

> diff --git a/drivers/net/dsa/yt921x.c b/drivers/net/dsa/yt921x.c
> index 42dca9617fb17..c5af64ea0c326 100644
> --- a/drivers/net/dsa/yt921x.c
> +++ b/drivers/net/dsa/yt921x.c
[ ... ]
> +static int
> +yt921x_dsa_port_setup_tc_tbf_port(struct dsa_switch *ds, int port,
> +				  const struct tc_tbf_qopt_offload *qopt)
> +{
> +	struct yt921x_priv *priv = to_yt921x_priv(ds);
> +	struct netlink_ext_ack *extack = qopt->extack;
> +	u32 ctrls[2];
> +	int res;
> +
> +	if (qopt->parent != TC_H_ROOT)
> +		return -EOPNOTSUPP;
> +
> +	switch (qopt->command) {
> +	case TC_TBF_STATS:
> +		return 0;

Is it intended to return 0 here without populating the hardware statistics?

When the driver handles this command by returning 0 without modifying
qopt->stats, it incorrectly signals to the TC core that hardware statistics
were successfully fetched. As a result, the subsystem will report
unmodified (typically zeroed) statistics, which hides any packets shaped
or dropped by the hardware.

Should this read the hardware statistic registers (like the newly defined
YT921X_PORTn_SHAPE_STAT) to update qopt->stats, or alternatively return
-EOPNOTSUPP to indicate a lack of support?