Merge branch 'add-tc-taprio-support-for-queuemaxsdu'

Vladimir Oltean says:

====================
Add tc-taprio support for queueMaxSDU

The tc-taprio offload mode supported by the Felix DSA driver has
limitations surrounding its guard bands.

The initial discussion was at:
https://lore.kernel.org/netdev/c7618025da6723418c56a54fe4683bd7@walle.cc/

with the latest status being that we now have a vsc9959_tas_guard_bands_update()
method which makes a best-guess attempt at how much useful space to
reserve for packet scheduling in a taprio interval, and how much to
reserve for guard bands.

IEEE 802.1Q actually does offer a tunable variable (queueMaxSDU) which
can determine the max MTU supported per traffic class. In turn we can
determine the size we need for the guard bands, depending on the
queueMaxSDU. This way we can make the guard band of small taprio
intervals smaller than one full MTU worth of transmission time, if we
know that said traffic class will transport only smaller packets.

As discussed with Gerhard Engleder, the queueMaxSDU may also be useful
in limiting the latency on an endpoint, if some of the TX queues are
outside of the control of the Linux driver.
https://patchwork.kernel.org/project/netdevbpf/patch/20220914153303.1792444-11-vladimir.oltean@nxp.com/

Allow input of queueMaxSDU through netlink into tc-taprio, offload it to
the hardware I have access to (LS1028A), and (implicitly) deny
non-default values to everyone else. Kurt Kanzenbach has also kindly
tested and shared a patch to offload this to hellcreek.

v3 at:
https://patchwork.kernel.org/project/netdevbpf/cover/20220927234746.1823648-1-vladimir.oltean@nxp.com/
v2 at:
https://patchwork.kernel.org/project/netdevbpf/list/?series=679954&state=*
v1 at:
https://patchwork.kernel.org/project/netdevbpf/cover/20220914153303.1792444-1-vladimir.oltean@nxp.com/
====================

Link: https://lore.kernel.org/r/20220928095204.2093716-1-vladimir.oltean@nxp.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/hirschmann/hellcreek.c

@@ -128,6 +128,16 @@ static void hellcreek_select_prio(struct hellcreek *hellcreek, int prio)
 	hellcreek_write(hellcreek, val, HR_PSEL);
 }
 
+static void hellcreek_select_port_prio(struct hellcreek *hellcreek, int port,
+				       int prio)
+{
+	u16 val = port << HR_PSEL_PTWSEL_SHIFT;
+
+	val |= prio << HR_PSEL_PRTCWSEL_SHIFT;
+
+	hellcreek_write(hellcreek, val, HR_PSEL);
+}
+
 static void hellcreek_select_counter(struct hellcreek *hellcreek, int counter)
 {
 	u16 val = counter << HR_CSEL_SHIFT;
@@ -1537,6 +1547,45 @@ hellcreek_port_prechangeupper(struct dsa_switch *ds, int port,
 	return ret;
 }
 
+static void hellcreek_setup_maxsdu(struct hellcreek *hellcreek, int port,
+				   const struct tc_taprio_qopt_offload *schedule)
+{
+	int tc;
+
+	for (tc = 0; tc < 8; ++tc) {
+		u32 max_sdu = schedule->max_sdu[tc] + VLAN_ETH_HLEN - ETH_FCS_LEN;
+		u16 val;
+
+		if (!schedule->max_sdu[tc])
+			continue;
+
+		dev_dbg(hellcreek->dev, "Configure max-sdu %u for tc %d on port %d\n",
+			max_sdu, tc, port);
+
+		hellcreek_select_port_prio(hellcreek, port, tc);
+
+		val = (max_sdu & HR_PTPRTCCFG_MAXSDU_MASK) << HR_PTPRTCCFG_MAXSDU_SHIFT;
+
+		hellcreek_write(hellcreek, val, HR_PTPRTCCFG);
+	}
+}
+
+static void hellcreek_reset_maxsdu(struct hellcreek *hellcreek, int port)
+{
+	int tc;
+
+	for (tc = 0; tc < 8; ++tc) {
+		u16 val;
+
+		hellcreek_select_port_prio(hellcreek, port, tc);
+
+		val = (HELLCREEK_DEFAULT_MAX_SDU & HR_PTPRTCCFG_MAXSDU_MASK)
+			<< HR_PTPRTCCFG_MAXSDU_SHIFT;
+
+		hellcreek_write(hellcreek, val, HR_PTPRTCCFG);
+	}
+}
+
 static void hellcreek_setup_gcl(struct hellcreek *hellcreek, int port,
 				const struct tc_taprio_qopt_offload *schedule)
 {
@@ -1720,7 +1769,10 @@ static int hellcreek_port_set_schedule(struct dsa_switch *ds, int port,
 	}
 	hellcreek_port->current_schedule = taprio_offload_get(taprio);
 
-	/* Then select port */
+	/* Configure max sdu */
+	hellcreek_setup_maxsdu(hellcreek, port, hellcreek_port->current_schedule);
+
+	/* Select tdg */
 	hellcreek_select_tgd(hellcreek, port);
 
 	/* Enable gating and keep defaults */
@@ -1772,7 +1824,10 @@ static int hellcreek_port_del_schedule(struct dsa_switch *ds, int port)
 		hellcreek_port->current_schedule = NULL;
 	}
 
-	/* Then select port */
+	/* Reset max sdu */
+	hellcreek_reset_maxsdu(hellcreek, port);
+
+	/* Select tgd */
 	hellcreek_select_tgd(hellcreek, port);
 
 	/* Disable gating and return to regular switching flow */
@@ -1809,22 +1864,43 @@ static bool hellcreek_validate_schedule(struct hellcreek *hellcreek,
 	return true;
 }
 
+static int hellcreek_tc_query_caps(struct tc_query_caps_base *base)
+{
+	switch (base->type) {
+	case TC_SETUP_QDISC_TAPRIO: {
+		struct tc_taprio_caps *caps = base->caps;
+
+		caps->supports_queue_max_sdu = true;
+
+		return 0;
+	}
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
 static int hellcreek_port_setup_tc(struct dsa_switch *ds, int port,
 				   enum tc_setup_type type, void *type_data)
 {
-	struct tc_taprio_qopt_offload *taprio = type_data;
 	struct hellcreek *hellcreek = ds->priv;
 
-	if (type != TC_SETUP_QDISC_TAPRIO)
-		return -EOPNOTSUPP;
+	switch (type) {
+	case TC_QUERY_CAPS:
+		return hellcreek_tc_query_caps(type_data);
+	case TC_SETUP_QDISC_TAPRIO: {
+		struct tc_taprio_qopt_offload *taprio = type_data;
 
-	if (!hellcreek_validate_schedule(hellcreek, taprio))
-		return -EOPNOTSUPP;
+		if (!hellcreek_validate_schedule(hellcreek, taprio))
+			return -EOPNOTSUPP;
 
-	if (taprio->enable)
-		return hellcreek_port_set_schedule(ds, port, taprio);
+		if (taprio->enable)
+			return hellcreek_port_set_schedule(ds, port, taprio);
 
-	return hellcreek_port_del_schedule(ds, port);
+		return hellcreek_port_del_schedule(ds, port);
+	}
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
 static const struct dsa_switch_ops hellcreek_ds_ops = {

drivers/net/dsa/hirschmann/hellcreek.h

@@ -37,6 +37,7 @@
 #define HELLCREEK_VLAN_UNTAGGED_MEMBER	0x1
 #define HELLCREEK_VLAN_TAGGED_MEMBER	0x3
 #define HELLCREEK_NUM_EGRESS_QUEUES	8
+#define HELLCREEK_DEFAULT_MAX_SDU	1536
 
 /* Register definitions */
 #define HR_MODID_C			(0 * 2)
@@ -72,6 +73,12 @@
 #define HR_PRTCCFG_PCP_TC_MAP_SHIFT	0
 #define HR_PRTCCFG_PCP_TC_MAP_MASK	GENMASK(2, 0)
 
+#define HR_PTPRTCCFG			(0xa9 * 2)
+#define HR_PTPRTCCFG_SET_QTRACK		BIT(15)
+#define HR_PTPRTCCFG_REJECT		BIT(14)
+#define HR_PTPRTCCFG_MAXSDU_SHIFT	0
+#define HR_PTPRTCCFG_MAXSDU_MASK	GENMASK(10, 0)
+
 #define HR_CSEL				(0x8d * 2)
 #define HR_CSEL_SHIFT			0
 #define HR_CSEL_MASK			GENMASK(7, 0)

drivers/net/dsa/ocelot/felix_vsc9959.c

@@ -1194,6 +1194,14 @@ static u32 vsc9959_port_qmaxsdu_get(struct ocelot *ocelot, int port, int tc)
 	}
 }
 
+static u32 vsc9959_tas_tc_max_sdu(struct tc_taprio_qopt_offload *taprio, int tc)
+{
+	if (!taprio || !taprio->max_sdu[tc])
+		return 0;
+
+	return taprio->max_sdu[tc] + ETH_HLEN + 2 * VLAN_HLEN + ETH_FCS_LEN;
+}
+
 /* Update QSYS_PORT_MAX_SDU to make sure the static guard bands added by the
  * switch (see the ALWAYS_GUARD_BAND_SCH_Q comment) are correct at all MTU
  * values (the default value is 1518). Also, for traffic class windows smaller
@@ -1203,6 +1211,7 @@ static u32 vsc9959_port_qmaxsdu_get(struct ocelot *ocelot, int port, int tc)
 static void vsc9959_tas_guard_bands_update(struct ocelot *ocelot, int port)
 {
 	struct ocelot_port *ocelot_port = ocelot->ports[port];
+	struct tc_taprio_qopt_offload *taprio;
 	u64 min_gate_len[OCELOT_NUM_TC];
 	int speed, picos_per_byte;
 	u64 needed_bit_time_ps;
@@ -1212,6 +1221,8 @@ static void vsc9959_tas_guard_bands_update(struct ocelot *ocelot, int port)
 
 	lockdep_assert_held(&ocelot->tas_lock);
 
+	taprio = ocelot_port->taprio;
+
 	val = ocelot_read_rix(ocelot, QSYS_TAG_CONFIG, port);
 	tas_speed = QSYS_TAG_CONFIG_LINK_SPEED_X(val);
 
@@ -1248,11 +1259,12 @@ static void vsc9959_tas_guard_bands_update(struct ocelot *ocelot, int port)
 		"port %d: max frame size %d needs %llu ps at speed %d\n",
 		port, maxlen, needed_bit_time_ps, speed);
 
-	vsc9959_tas_min_gate_lengths(ocelot_port->taprio, min_gate_len);
+	vsc9959_tas_min_gate_lengths(taprio, min_gate_len);
 
 	mutex_lock(&ocelot->fwd_domain_lock);
 
 	for (tc = 0; tc < OCELOT_NUM_TC; tc++) {
+		u32 requested_max_sdu = vsc9959_tas_tc_max_sdu(taprio, tc);
 		u64 remaining_gate_len_ps;
 		u32 max_sdu;
 
@@ -1263,7 +1275,7 @@ static void vsc9959_tas_guard_bands_update(struct ocelot *ocelot, int port)
 			/* Setting QMAXSDU_CFG to 0 disables oversized frame
 			 * dropping.
 			 */
-			max_sdu = 0;
+			max_sdu = requested_max_sdu;
 			dev_dbg(ocelot->dev,
 				"port %d tc %d min gate len %llu"
 				", sending all frames\n",
@@ -1294,6 +1306,10 @@ static void vsc9959_tas_guard_bands_update(struct ocelot *ocelot, int port)
 			 */
 			if (max_sdu > 20)
 				max_sdu -= 20;
+
+			if (requested_max_sdu && requested_max_sdu < max_sdu)
+				max_sdu = requested_max_sdu;
+
 			dev_info(ocelot->dev,
 				 "port %d tc %d min gate length %llu"
 				 " ns not enough for max frame size %d at %d"
@@ -1583,6 +1599,21 @@ static int vsc9959_qos_port_cbs_set(struct dsa_switch *ds, int port,
 	return 0;
 }
 
+static int vsc9959_qos_query_caps(struct tc_query_caps_base *base)
+{
+	switch (base->type) {
+	case TC_SETUP_QDISC_TAPRIO: {
+		struct tc_taprio_caps *caps = base->caps;
+
+		caps->supports_queue_max_sdu = true;
+
+		return 0;
+	}
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
 static int vsc9959_port_setup_tc(struct dsa_switch *ds, int port,
 				 enum tc_setup_type type,
 				 void *type_data)
@@ -1590,6 +1621,8 @@ static int vsc9959_port_setup_tc(struct dsa_switch *ds, int port,
 	struct ocelot *ocelot = ds->priv;
 
 	switch (type) {
+	case TC_QUERY_CAPS:
+		return vsc9959_qos_query_caps(type_data);
 	case TC_SETUP_QDISC_TAPRIO:
 		return vsc9959_qos_port_tas_set(ocelot, port, type_data);
 	case TC_SETUP_QDISC_CBS:

drivers/net/ethernet/freescale/enetc/enetc.c

@@ -2116,13 +2116,14 @@ static void enetc_setup_rxbdr(struct enetc_hw *hw, struct enetc_bdr *rx_ring)
 
 static void enetc_setup_bdrs(struct enetc_ndev_priv *priv)
 {
+	struct enetc_hw *hw = &priv->si->hw;
 	int i;
 
 	for (i = 0; i < priv->num_tx_rings; i++)
-		enetc_setup_txbdr(&priv->si->hw, priv->tx_ring[i]);
+		enetc_setup_txbdr(hw, priv->tx_ring[i]);
 
 	for (i = 0; i < priv->num_rx_rings; i++)
-		enetc_setup_rxbdr(&priv->si->hw, priv->rx_ring[i]);
+		enetc_setup_rxbdr(hw, priv->rx_ring[i]);
 }
 
 static void enetc_clear_rxbdr(struct enetc_hw *hw, struct enetc_bdr *rx_ring)
@@ -2155,13 +2156,14 @@ static void enetc_clear_txbdr(struct enetc_hw *hw, struct enetc_bdr *tx_ring)
 
 static void enetc_clear_bdrs(struct enetc_ndev_priv *priv)
 {
+	struct enetc_hw *hw = &priv->si->hw;
 	int i;
 
 	for (i = 0; i < priv->num_tx_rings; i++)
-		enetc_clear_txbdr(&priv->si->hw, priv->tx_ring[i]);
+		enetc_clear_txbdr(hw, priv->tx_ring[i]);
 
 	for (i = 0; i < priv->num_rx_rings; i++)
-		enetc_clear_rxbdr(&priv->si->hw, priv->rx_ring[i]);
+		enetc_clear_rxbdr(hw, priv->rx_ring[i]);
 
 	udelay(1);
 }
@@ -2169,13 +2171,13 @@ static void enetc_clear_bdrs(struct enetc_ndev_priv *priv)
 static int enetc_setup_irqs(struct enetc_ndev_priv *priv)
 {
 	struct pci_dev *pdev = priv->si->pdev;
+	struct enetc_hw *hw = &priv->si->hw;
 	int i, j, err;
 
 	for (i = 0; i < priv->bdr_int_num; i++) {
 		int irq = pci_irq_vector(pdev, ENETC_BDR_INT_BASE_IDX + i);
 		struct enetc_int_vector *v = priv->int_vector[i];
 		int entry = ENETC_BDR_INT_BASE_IDX + i;
-		struct enetc_hw *hw = &priv->si->hw;
 
 		snprintf(v->name, sizeof(v->name), "%s-rxtx%d",
 			 priv->ndev->name, i);
@@ -2263,13 +2265,14 @@ static void enetc_setup_interrupts(struct enetc_ndev_priv *priv)
 
 static void enetc_clear_interrupts(struct enetc_ndev_priv *priv)
 {
+	struct enetc_hw *hw = &priv->si->hw;
 	int i;
 
 	for (i = 0; i < priv->num_tx_rings; i++)
-		enetc_txbdr_wr(&priv->si->hw, i, ENETC_TBIER, 0);
+		enetc_txbdr_wr(hw, i, ENETC_TBIER, 0);
 
 	for (i = 0; i < priv->num_rx_rings; i++)
-		enetc_rxbdr_wr(&priv->si->hw, i, ENETC_RBIER, 0);
+		enetc_rxbdr_wr(hw, i, ENETC_RBIER, 0);
 }
 
 static int enetc_phylink_connect(struct net_device *ndev)
@@ -2436,6 +2439,7 @@ int enetc_setup_tc_mqprio(struct net_device *ndev, void *type_data)
 {
 	struct enetc_ndev_priv *priv = netdev_priv(ndev);
 	struct tc_mqprio_qopt *mqprio = type_data;
+	struct enetc_hw *hw = &priv->si->hw;
 	struct enetc_bdr *tx_ring;
 	int num_stack_tx_queues;
 	u8 num_tc;
@@ -2452,7 +2456,7 @@ int enetc_setup_tc_mqprio(struct net_device *ndev, void *type_data)
 		/* Reset all ring priorities to 0 */
 		for (i = 0; i < priv->num_tx_rings; i++) {
 			tx_ring = priv->tx_ring[i];
-			enetc_set_bdr_prio(&priv->si->hw, tx_ring->index, 0);
+			enetc_set_bdr_prio(hw, tx_ring->index, 0);
 		}
 
 		return 0;
@@ -2471,7 +2475,7 @@ int enetc_setup_tc_mqprio(struct net_device *ndev, void *type_data)
 	 */
 	for (i = 0; i < num_tc; i++) {
 		tx_ring = priv->tx_ring[i];
-		enetc_set_bdr_prio(&priv->si->hw, tx_ring->index, i);
+		enetc_set_bdr_prio(hw, tx_ring->index, i);
 	}
 
 	/* Reset the number of netdev queues based on the TC count */
@@ -2584,19 +2588,21 @@ static int enetc_set_rss(struct net_device *ndev, int en)
 static void enetc_enable_rxvlan(struct net_device *ndev, bool en)
 {
 	struct enetc_ndev_priv *priv = netdev_priv(ndev);
+	struct enetc_hw *hw = &priv->si->hw;
 	int i;
 
 	for (i = 0; i < priv->num_rx_rings; i++)
-		enetc_bdr_enable_rxvlan(&priv->si->hw, i, en);
+		enetc_bdr_enable_rxvlan(hw, i, en);
 }
 
 static void enetc_enable_txvlan(struct net_device *ndev, bool en)
 {
 	struct enetc_ndev_priv *priv = netdev_priv(ndev);
+	struct enetc_hw *hw = &priv->si->hw;
 	int i;
 
 	for (i = 0; i < priv->num_tx_rings; i++)
-		enetc_bdr_enable_txvlan(&priv->si->hw, i, en);
+		enetc_bdr_enable_txvlan(hw, i, en);
 }
 
 void enetc_set_features(struct net_device *ndev, netdev_features_t features)

drivers/net/ethernet/freescale/enetc/enetc.h

@@ -453,7 +453,11 @@ static inline void enetc_cbd_free_data_mem(struct enetc_si *si, int size,
 			  data, *dma);
 }
 
+void enetc_reset_ptcmsdur(struct enetc_hw *hw);
+void enetc_set_ptcmsdur(struct enetc_hw *hw, u32 *queue_max_sdu);
+
 #ifdef CONFIG_FSL_ENETC_QOS
+int enetc_qos_query_caps(struct net_device *ndev, void *type_data);
 int enetc_setup_tc_taprio(struct net_device *ndev, void *type_data);
 void enetc_sched_speed_set(struct enetc_ndev_priv *priv, int speed);
 int enetc_setup_tc_cbs(struct net_device *ndev, void *type_data);
@@ -467,19 +471,20 @@ int enetc_set_psfp(struct net_device *ndev, bool en);
 
 static inline void enetc_get_max_cap(struct enetc_ndev_priv *priv)
 {
+	struct enetc_hw *hw = &priv->si->hw;
 	u32 reg;
 
-	reg = enetc_port_rd(&priv->si->hw, ENETC_PSIDCAPR);
+	reg = enetc_port_rd(hw, ENETC_PSIDCAPR);
 	priv->psfp_cap.max_streamid = reg & ENETC_PSIDCAPR_MSK;
 	/* Port stream filter capability */
-	reg = enetc_port_rd(&priv->si->hw, ENETC_PSFCAPR);
+	reg = enetc_port_rd(hw, ENETC_PSFCAPR);
 	priv->psfp_cap.max_psfp_filter = reg & ENETC_PSFCAPR_MSK;
 	/* Port stream gate capability */
-	reg = enetc_port_rd(&priv->si->hw, ENETC_PSGCAPR);
+	reg = enetc_port_rd(hw, ENETC_PSGCAPR);
 	priv->psfp_cap.max_psfp_gate = (reg & ENETC_PSGCAPR_SGIT_MSK);
 	priv->psfp_cap.max_psfp_gatelist = (reg & ENETC_PSGCAPR_GCL_MSK) >> 16;
 	/* Port flow meter capability */
-	reg = enetc_port_rd(&priv->si->hw, ENETC_PFMCAPR);
+	reg = enetc_port_rd(hw, ENETC_PFMCAPR);
 	priv->psfp_cap.max_psfp_meter = reg & ENETC_PFMCAPR_MSK;
 }
 
@@ -520,6 +525,7 @@ static inline int enetc_psfp_disable(struct enetc_ndev_priv *priv)
 }
 
 #else
+#define enetc_qos_query_caps(ndev, type_data) -EOPNOTSUPP
 #define enetc_setup_tc_taprio(ndev, type_data) -EOPNOTSUPP
 #define enetc_sched_speed_set(priv, speed) (void)0
 #define enetc_setup_tc_cbs(ndev, type_data) -EOPNOTSUPP

drivers/net/ethernet/freescale/enetc/enetc_hw.h

@@ -945,13 +945,13 @@ static inline u32 enetc_usecs_to_cycles(u32 usecs)
 }
 
 /* port time gating control register */
-#define ENETC_QBV_PTGCR_OFFSET		0x11a00
-#define ENETC_QBV_TGE			BIT(31)
-#define ENETC_QBV_TGPE			BIT(30)
+#define ENETC_PTGCR			0x11a00
+#define ENETC_PTGCR_TGE			BIT(31)
+#define ENETC_PTGCR_TGPE		BIT(30)
 
 /* Port time gating capability register */
-#define ENETC_QBV_PTGCAPR_OFFSET	0x11a08
-#define ENETC_QBV_MAX_GCL_LEN_MASK	GENMASK(15, 0)
+#define ENETC_PTGCAPR			0x11a08
+#define ENETC_PTGCAPR_MAX_GCL_LEN_MASK	GENMASK(15, 0)
 
 /* Port time specific departure */
 #define ENETC_PTCTSDR(n)	(0x1210 + 4 * (n))

drivers/net/ethernet/freescale/enetc/enetc_pf.c

@@ -516,15 +516,34 @@ static void enetc_port_si_configure(struct enetc_si *si)
 	enetc_port_wr(hw, ENETC_PSIVLANFMR, ENETC_PSIVLANFMR_VS);
 }
 
-static void enetc_configure_port_mac(struct enetc_hw *hw)
+void enetc_set_ptcmsdur(struct enetc_hw *hw, u32 *max_sdu)
 {
 	int tc;
 
-	enetc_port_wr(hw, ENETC_PM0_MAXFRM,
-		      ENETC_SET_MAXFRM(ENETC_RX_MAXFRM_SIZE));
+	for (tc = 0; tc < 8; tc++) {
+		u32 val = ENETC_MAC_MAXFRM_SIZE;
+
+		if (max_sdu[tc])
+			val = max_sdu[tc] + VLAN_ETH_HLEN;
+
+		enetc_port_wr(hw, ENETC_PTCMSDUR(tc), val);
+	}
+}
+
+void enetc_reset_ptcmsdur(struct enetc_hw *hw)
+{
+	int tc;
 
 	for (tc = 0; tc < 8; tc++)
 		enetc_port_wr(hw, ENETC_PTCMSDUR(tc), ENETC_MAC_MAXFRM_SIZE);
+}
+
+static void enetc_configure_port_mac(struct enetc_hw *hw)
+{
+	enetc_port_wr(hw, ENETC_PM0_MAXFRM,
+		      ENETC_SET_MAXFRM(ENETC_RX_MAXFRM_SIZE));
+
+	enetc_reset_ptcmsdur(hw);
 
 	enetc_port_wr(hw, ENETC_PM0_CMD_CFG, ENETC_PM0_CMD_PHY_TX_EN |
 		      ENETC_PM0_CMD_TXP	| ENETC_PM0_PROMISC);
@@ -738,6 +757,8 @@ static int enetc_pf_setup_tc(struct net_device *ndev, enum tc_setup_type type,
 			     void *type_data)
 {
 	switch (type) {
+	case TC_QUERY_CAPS:
+		return enetc_qos_query_caps(ndev, type_data);
 	case TC_SETUP_QDISC_MQPRIO:
 		return enetc_setup_tc_mqprio(ndev, type_data);
 	case TC_SETUP_QDISC_TAPRIO:

drivers/net/ethernet/freescale/enetc/enetc_qos.c

@@ -7,18 +7,19 @@
 #include <linux/math64.h>
 #include <linux/refcount.h>
 #include <net/pkt_cls.h>
+#include <net/pkt_sched.h>
 #include <net/tc_act/tc_gate.h>
 
 static u16 enetc_get_max_gcl_len(struct enetc_hw *hw)
 {
-	return enetc_rd(hw, ENETC_QBV_PTGCAPR_OFFSET)
-		& ENETC_QBV_MAX_GCL_LEN_MASK;
+	return enetc_rd(hw, ENETC_PTGCAPR) & ENETC_PTGCAPR_MAX_GCL_LEN_MASK;
 }
 
 void enetc_sched_speed_set(struct enetc_ndev_priv *priv, int speed)
 {
+	struct enetc_hw *hw = &priv->si->hw;
 	u32 old_speed = priv->speed;
-	u32 pspeed;
+	u32 pspeed, tmp;
 
 	if (speed == old_speed)
 		return;
@@ -39,16 +40,15 @@ void enetc_sched_speed_set(struct enetc_ndev_priv *priv, int speed)
 	}
 
 	priv->speed = speed;
-	enetc_port_wr(&priv->si->hw, ENETC_PMR,
-		      (enetc_port_rd(&priv->si->hw, ENETC_PMR)
-		      & (~ENETC_PMR_PSPEED_MASK))
-		      | pspeed);
+	tmp = enetc_port_rd(hw, ENETC_PMR);
+	enetc_port_wr(hw, ENETC_PMR, (tmp & ~ENETC_PMR_PSPEED_MASK) | pspeed);
 }
 
 static int enetc_setup_taprio(struct net_device *ndev,
 			      struct tc_taprio_qopt_offload *admin_conf)
 {
 	struct enetc_ndev_priv *priv = netdev_priv(ndev);
+	struct enetc_hw *hw = &priv->si->hw;
 	struct enetc_cbd cbd = {.cmd = 0};
 	struct tgs_gcl_conf *gcl_config;
 	struct tgs_gcl_data *gcl_data;
@@ -61,15 +61,14 @@ static int enetc_setup_taprio(struct net_device *ndev,
 	int err;
 	int i;
 
-	if (admin_conf->num_entries > enetc_get_max_gcl_len(&priv->si->hw))
+	if (admin_conf->num_entries > enetc_get_max_gcl_len(hw))
 		return -EINVAL;
 	gcl_len = admin_conf->num_entries;
 
-	tge = enetc_rd(&priv->si->hw, ENETC_QBV_PTGCR_OFFSET);
+	tge = enetc_rd(hw, ENETC_PTGCR);
 	if (!admin_conf->enable) {
-		enetc_wr(&priv->si->hw,
-			 ENETC_QBV_PTGCR_OFFSET,
-			 tge & (~ENETC_QBV_TGE));
+		enetc_wr(hw, ENETC_PTGCR, tge & ~ENETC_PTGCR_TGE);
+		enetc_reset_ptcmsdur(hw);
 
 		priv->active_offloads &= ~ENETC_F_QBV;
 
@@ -117,27 +116,28 @@ static int enetc_setup_taprio(struct net_device *ndev,
 	cbd.cls = BDCR_CMD_PORT_GCL;
 	cbd.status_flags = 0;
 
-	enetc_wr(&priv->si->hw, ENETC_QBV_PTGCR_OFFSET,
-		 tge | ENETC_QBV_TGE);
+	enetc_wr(hw, ENETC_PTGCR, tge | ENETC_PTGCR_TGE);
 
 	err = enetc_send_cmd(priv->si, &cbd);
 	if (err)
-		enetc_wr(&priv->si->hw,
-			 ENETC_QBV_PTGCR_OFFSET,
-			 tge & (~ENETC_QBV_TGE));
+		enetc_wr(hw, ENETC_PTGCR, tge & ~ENETC_PTGCR_TGE);
 
 	enetc_cbd_free_data_mem(priv->si, data_size, tmp, &dma);
 
-	if (!err)
-		priv->active_offloads |= ENETC_F_QBV;
+	if (err)
+		return err;
 
-	return err;
+	enetc_set_ptcmsdur(hw, admin_conf->max_sdu);
+	priv->active_offloads |= ENETC_F_QBV;
+
+	return 0;
 }
 
 int enetc_setup_tc_taprio(struct net_device *ndev, void *type_data)
 {
 	struct tc_taprio_qopt_offload *taprio = type_data;
 	struct enetc_ndev_priv *priv = netdev_priv(ndev);
+	struct enetc_hw *hw = &priv->si->hw;
 	int err;
 	int i;
 
@@ -147,16 +147,14 @@ int enetc_setup_tc_taprio(struct net_device *ndev, void *type_data)
 			return -EBUSY;
 
 	for (i = 0; i < priv->num_tx_rings; i++)
-		enetc_set_bdr_prio(&priv->si->hw,
-				   priv->tx_ring[i]->index,
+		enetc_set_bdr_prio(hw, priv->tx_ring[i]->index,
 				   taprio->enable ? i : 0);
 
 	err = enetc_setup_taprio(ndev, taprio);
 
 	if (err)
 		for (i = 0; i < priv->num_tx_rings; i++)
-			enetc_set_bdr_prio(&priv->si->hw,
-					   priv->tx_ring[i]->index,
+			enetc_set_bdr_prio(hw, priv->tx_ring[i]->index,
 					   taprio->enable ? 0 : i);
 
 	return err;
@@ -178,7 +176,7 @@ int enetc_setup_tc_cbs(struct net_device *ndev, void *type_data)
 	struct tc_cbs_qopt_offload *cbs = type_data;
 	u32 port_transmit_rate = priv->speed;
 	u8 tc_nums = netdev_get_num_tc(ndev);
-	struct enetc_si *si = priv->si;
+	struct enetc_hw *hw = &priv->si->hw;
 	u32 hi_credit_bit, hi_credit_reg;
 	u32 max_interference_size;
 	u32 port_frame_max_size;
@@ -199,15 +197,15 @@ int enetc_setup_tc_cbs(struct net_device *ndev, void *type_data)
 		 * lower than this TC have been disabled.
 		 */
 		if (tc == prio_top &&
-		    enetc_get_cbs_enable(&si->hw, prio_next)) {
+		    enetc_get_cbs_enable(hw, prio_next)) {
 			dev_err(&ndev->dev,
 				"Disable TC%d before disable TC%d\n",
 				prio_next, tc);
 			return -EINVAL;
 		}
 
-		enetc_port_wr(&si->hw, ENETC_PTCCBSR1(tc), 0);
-		enetc_port_wr(&si->hw, ENETC_PTCCBSR0(tc), 0);
+		enetc_port_wr(hw, ENETC_PTCCBSR1(tc), 0);
+		enetc_port_wr(hw, ENETC_PTCCBSR0(tc), 0);
 
 		return 0;
 	}
@@ -224,13 +222,13 @@ int enetc_setup_tc_cbs(struct net_device *ndev, void *type_data)
 	 * higher than this TC have been enabled.
 	 */
 	if (tc == prio_next) {
-		if (!enetc_get_cbs_enable(&si->hw, prio_top)) {
+		if (!enetc_get_cbs_enable(hw, prio_top)) {
 			dev_err(&ndev->dev,
 				"Enable TC%d first before enable TC%d\n",
 				prio_top, prio_next);
 			return -EINVAL;
 		}
-		bw_sum += enetc_get_cbs_bw(&si->hw, prio_top);
+		bw_sum += enetc_get_cbs_bw(hw, prio_top);
 	}
 
 	if (bw_sum + bw >= 100) {
@@ -239,7 +237,7 @@ int enetc_setup_tc_cbs(struct net_device *ndev, void *type_data)
 		return -EINVAL;
 	}
 
-	enetc_port_rd(&si->hw, ENETC_PTCMSDUR(tc));
+	enetc_port_rd(hw, ENETC_PTCMSDUR(tc));
 
 	/* For top prio TC, the max_interfrence_size is maxSizedFrame.
 	 *
@@ -259,8 +257,8 @@ int enetc_setup_tc_cbs(struct net_device *ndev, void *type_data)
 		u32 m0, ma, r0, ra;
 
 		m0 = port_frame_max_size * 8;
-		ma = enetc_port_rd(&si->hw, ENETC_PTCMSDUR(prio_top)) * 8;
-		ra = enetc_get_cbs_bw(&si->hw, prio_top) *
+		ma = enetc_port_rd(hw, ENETC_PTCMSDUR(prio_top)) * 8;
+		ra = enetc_get_cbs_bw(hw, prio_top) *
 			port_transmit_rate * 10000ULL;
 		r0 = port_transmit_rate * 1000000ULL;
 		max_interference_size = m0 + ma +
@@ -280,10 +278,10 @@ int enetc_setup_tc_cbs(struct net_device *ndev, void *type_data)
 	hi_credit_reg = (u32)div_u64((ENETC_CLK * 100ULL) * hi_credit_bit,
 				     port_transmit_rate * 1000000ULL);
 
-	enetc_port_wr(&si->hw, ENETC_PTCCBSR1(tc), hi_credit_reg);
+	enetc_port_wr(hw, ENETC_PTCCBSR1(tc), hi_credit_reg);
 
 	/* Set bw register and enable this traffic class */
-	enetc_port_wr(&si->hw, ENETC_PTCCBSR0(tc), bw | ENETC_CBSE);
+	enetc_port_wr(hw, ENETC_PTCCBSR0(tc), bw | ENETC_CBSE);
 
 	return 0;
 }
@@ -293,6 +291,7 @@ int enetc_setup_tc_txtime(struct net_device *ndev, void *type_data)
 	struct enetc_ndev_priv *priv = netdev_priv(ndev);
 	struct tc_etf_qopt_offload *qopt = type_data;
 	u8 tc_nums = netdev_get_num_tc(ndev);
+	struct enetc_hw *hw = &priv->si->hw;
 	int tc;
 
 	if (!tc_nums)
@@ -304,12 +303,11 @@ int enetc_setup_tc_txtime(struct net_device *ndev, void *type_data)
 		return -EINVAL;
 
 	/* TSD and Qbv are mutually exclusive in hardware */
-	if (enetc_rd(&priv->si->hw, ENETC_QBV_PTGCR_OFFSET) & ENETC_QBV_TGE)
+	if (enetc_rd(hw, ENETC_PTGCR) & ENETC_PTGCR_TGE)
 		return -EBUSY;
 
 	priv->tx_ring[tc]->tsd_enable = qopt->enable;
-	enetc_port_wr(&priv->si->hw, ENETC_PTCTSDR(tc),
-		      qopt->enable ? ENETC_TSDE : 0);
+	enetc_port_wr(hw, ENETC_PTCTSDR(tc), qopt->enable ? ENETC_TSDE : 0);
 
 	return 0;
 }
@@ -1601,3 +1599,23 @@ int enetc_setup_tc_psfp(struct net_device *ndev, void *type_data)
 
 	return 0;
 }
+
+int enetc_qos_query_caps(struct net_device *ndev, void *type_data)
+{
+	struct enetc_ndev_priv *priv = netdev_priv(ndev);
+	struct tc_query_caps_base *base = type_data;
+	struct enetc_si *si = priv->si;
+
+	switch (base->type) {
+	case TC_SETUP_QDISC_TAPRIO: {
+		struct tc_taprio_caps *caps = base->caps;
+
+		if (si->hw_features & ENETC_SI_F_QBV)
+			caps->supports_queue_max_sdu = true;
+
+		return 0;
+	}
+	default:
+		return -EOPNOTSUPP;
+	}
+}

include/linux/netdevice.h

@@ -940,6 +940,7 @@ struct net_device_path_ctx {
 };
 
 enum tc_setup_type {
+	TC_QUERY_CAPS,
 	TC_SETUP_QDISC_MQPRIO,
 	TC_SETUP_CLSU32,
 	TC_SETUP_CLSFLOWER,

include/net/pkt_sched.h

@@ -141,6 +141,11 @@ static inline struct net *qdisc_net(struct Qdisc *q)
 	return dev_net(q->dev_queue->dev);
 }
 
+struct tc_query_caps_base {
+	enum tc_setup_type type;
+	void *caps;
+};
+
 struct tc_cbs_qopt_offload {
 	u8 enable;
 	s32 queue;
@@ -155,6 +160,10 @@ struct tc_etf_qopt_offload {
 	s32 queue;
 };
 
+struct tc_taprio_caps {
+	bool supports_queue_max_sdu:1;
+};
+
 struct tc_taprio_sched_entry {
 	u8 command; /* TC_TAPRIO_CMD_* */
 
@@ -168,6 +177,7 @@ struct tc_taprio_qopt_offload {
 	ktime_t base_time;
 	u64 cycle_time;
 	u64 cycle_time_extension;
+	u32 max_sdu[TC_MAX_QUEUE];
 
 	size_t num_entries;
 	struct tc_taprio_sched_entry entries[];

include/net/sch_generic.h

@@ -677,6 +677,9 @@ qdisc_offload_graft_helper(struct net_device *dev, struct Qdisc *sch,
 {
 }
 #endif
+void qdisc_offload_query_caps(struct net_device *dev,
+			      enum tc_setup_type type,
+			      void *caps, size_t caps_len);
 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 			  const struct Qdisc_ops *ops,
 			  struct netlink_ext_ack *extack);

include/uapi/linux/pkt_sched.h

@@ -1232,6 +1232,16 @@ enum {
 #define TCA_TAPRIO_ATTR_FLAG_TXTIME_ASSIST	_BITUL(0)
 #define TCA_TAPRIO_ATTR_FLAG_FULL_OFFLOAD	_BITUL(1)
 
+enum {
+	TCA_TAPRIO_TC_ENTRY_UNSPEC,
+	TCA_TAPRIO_TC_ENTRY_INDEX,		/* u32 */
+	TCA_TAPRIO_TC_ENTRY_MAX_SDU,		/* u32 */
+
+	/* add new constants above here */
+	__TCA_TAPRIO_TC_ENTRY_CNT,
+	TCA_TAPRIO_TC_ENTRY_MAX = (__TCA_TAPRIO_TC_ENTRY_CNT - 1)
+};
+
 enum {
 	TCA_TAPRIO_ATTR_UNSPEC,
 	TCA_TAPRIO_ATTR_PRIOMAP, /* struct tc_mqprio_qopt */
@@ -1245,6 +1255,7 @@ enum {
 	TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME_EXTENSION, /* s64 */
 	TCA_TAPRIO_ATTR_FLAGS, /* u32 */
 	TCA_TAPRIO_ATTR_TXTIME_DELAY, /* u32 */
+	TCA_TAPRIO_ATTR_TC_ENTRY, /* nest */
 	__TCA_TAPRIO_ATTR_MAX,
 };
 

net/sched/sch_api.c

@@ -868,6 +868,23 @@ void qdisc_offload_graft_helper(struct net_device *dev, struct Qdisc *sch,
 }
 EXPORT_SYMBOL(qdisc_offload_graft_helper);
 
+void qdisc_offload_query_caps(struct net_device *dev,
+			      enum tc_setup_type type,
+			      void *caps, size_t caps_len)
+{
+	const struct net_device_ops *ops = dev->netdev_ops;
+	struct tc_query_caps_base base = {
+		.type = type,
+		.caps = caps,
+	};
+
+	memset(caps, 0, caps_len);
+
+	if (ops->ndo_setup_tc)
+		ops->ndo_setup_tc(dev, TC_QUERY_CAPS, &base);
+}
+EXPORT_SYMBOL(qdisc_offload_query_caps);
+
 static void qdisc_offload_graft_root(struct net_device *dev,
 				     struct Qdisc *new, struct Qdisc *old,
 				     struct netlink_ext_ack *extack)

net/sched/sch_taprio.c

@@ -78,6 +78,8 @@ struct taprio_sched {
 	struct sched_gate_list __rcu *admin_sched;
 	struct hrtimer advance_timer;
 	struct list_head taprio_list;
+	u32 max_frm_len[TC_MAX_QUEUE]; /* for the fast path */
+	u32 max_sdu[TC_MAX_QUEUE]; /* for dump and offloading */
 	u32 txtime_delay;
 };
 
@@ -415,6 +417,9 @@ static int taprio_enqueue_one(struct sk_buff *skb, struct Qdisc *sch,
 			      struct Qdisc *child, struct sk_buff **to_free)
 {
 	struct taprio_sched *q = qdisc_priv(sch);
+	struct net_device *dev = qdisc_dev(sch);
+	int prio = skb->priority;
+	u8 tc;
 
 	/* sk_flags are only safe to use on full sockets. */
 	if (skb->sk && sk_fullsock(skb->sk) && sock_flag(skb->sk, SOCK_TXTIME)) {
@@ -426,6 +431,11 @@ static int taprio_enqueue_one(struct sk_buff *skb, struct Qdisc *sch,
 			return qdisc_drop(skb, sch, to_free);
 	}
 
+	/* Devices with full offload are expected to honor this in hardware */
+	tc = netdev_get_prio_tc_map(dev, prio);
+	if (skb->len > q->max_frm_len[tc])
+		return qdisc_drop(skb, sch, to_free);
+
 	qdisc_qstats_backlog_inc(sch, skb);
 	sch->q.qlen++;
 
@@ -754,6 +764,11 @@ static const struct nla_policy entry_policy[TCA_TAPRIO_SCHED_ENTRY_MAX + 1] = {
 	[TCA_TAPRIO_SCHED_ENTRY_INTERVAL]  = { .type = NLA_U32 },
 };
 
+static const struct nla_policy taprio_tc_policy[TCA_TAPRIO_TC_ENTRY_MAX + 1] = {
+	[TCA_TAPRIO_TC_ENTRY_INDEX]	   = { .type = NLA_U32 },
+	[TCA_TAPRIO_TC_ENTRY_MAX_SDU]	   = { .type = NLA_U32 },
+};
+
 static const struct nla_policy taprio_policy[TCA_TAPRIO_ATTR_MAX + 1] = {
 	[TCA_TAPRIO_ATTR_PRIOMAP]	       = {
 		.len = sizeof(struct tc_mqprio_qopt)
@@ -766,6 +781,7 @@ static const struct nla_policy taprio_policy[TCA_TAPRIO_ATTR_MAX + 1] = {
 	[TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME_EXTENSION] = { .type = NLA_S64 },
 	[TCA_TAPRIO_ATTR_FLAGS]                      = { .type = NLA_U32 },
 	[TCA_TAPRIO_ATTR_TXTIME_DELAY]		     = { .type = NLA_U32 },
+	[TCA_TAPRIO_ATTR_TC_ENTRY]		     = { .type = NLA_NESTED },
 };
 
 static int fill_sched_entry(struct taprio_sched *q, struct nlattr **tb,
@@ -1216,7 +1232,8 @@ static int taprio_enable_offload(struct net_device *dev,
 {
 	const struct net_device_ops *ops = dev->netdev_ops;
 	struct tc_taprio_qopt_offload *offload;
-	int err = 0;
+	struct tc_taprio_caps caps;
+	int tc, err = 0;
 
 	if (!ops->ndo_setup_tc) {
 		NL_SET_ERR_MSG(extack,
@@ -1224,6 +1241,19 @@ static int taprio_enable_offload(struct net_device *dev,
 		return -EOPNOTSUPP;
 	}
 
+	qdisc_offload_query_caps(dev, TC_SETUP_QDISC_TAPRIO,
+				 &caps, sizeof(caps));
+
+	if (!caps.supports_queue_max_sdu) {
+		for (tc = 0; tc < TC_MAX_QUEUE; tc++) {
+			if (q->max_sdu[tc]) {
+				NL_SET_ERR_MSG_MOD(extack,
+						   "Device does not handle queueMaxSDU");
+				return -EOPNOTSUPP;
+			}
+		}
+	}
+
 	offload = taprio_offload_alloc(sched->num_entries);
 	if (!offload) {
 		NL_SET_ERR_MSG(extack,
@@ -1233,6 +1263,9 @@ static int taprio_enable_offload(struct net_device *dev,
 	offload->enable = 1;
 	taprio_sched_to_offload(dev, sched, offload);
 
+	for (tc = 0; tc < TC_MAX_QUEUE; tc++)
+		offload->max_sdu[tc] = q->max_sdu[tc];
+
 	err = ops->ndo_setup_tc(dev, TC_SETUP_QDISC_TAPRIO, offload);
 	if (err < 0) {
 		NL_SET_ERR_MSG(extack,
@@ -1367,6 +1400,89 @@ static int taprio_parse_clockid(struct Qdisc *sch, struct nlattr **tb,
 	return err;
 }
 
+static int taprio_parse_tc_entry(struct Qdisc *sch,
+				 struct nlattr *opt,
+				 u32 max_sdu[TC_QOPT_MAX_QUEUE],
+				 unsigned long *seen_tcs,
+				 struct netlink_ext_ack *extack)
+{
+	struct nlattr *tb[TCA_TAPRIO_TC_ENTRY_MAX + 1] = { };
+	struct net_device *dev = qdisc_dev(sch);
+	u32 val = 0;
+	int err, tc;
+
+	err = nla_parse_nested(tb, TCA_TAPRIO_TC_ENTRY_MAX, opt,
+			       taprio_tc_policy, extack);
+	if (err < 0)
+		return err;
+
+	if (!tb[TCA_TAPRIO_TC_ENTRY_INDEX]) {
+		NL_SET_ERR_MSG_MOD(extack, "TC entry index missing");
+		return -EINVAL;
+	}
+
+	tc = nla_get_u32(tb[TCA_TAPRIO_TC_ENTRY_INDEX]);
+	if (tc >= TC_QOPT_MAX_QUEUE) {
+		NL_SET_ERR_MSG_MOD(extack, "TC entry index out of range");
+		return -ERANGE;
+	}
+
+	if (*seen_tcs & BIT(tc)) {
+		NL_SET_ERR_MSG_MOD(extack, "Duplicate TC entry");
+		return -EINVAL;
+	}
+
+	*seen_tcs |= BIT(tc);
+
+	if (tb[TCA_TAPRIO_TC_ENTRY_MAX_SDU])
+		val = nla_get_u32(tb[TCA_TAPRIO_TC_ENTRY_MAX_SDU]);
+
+	if (val > dev->max_mtu) {
+		NL_SET_ERR_MSG_MOD(extack, "TC max SDU exceeds device max MTU");
+		return -ERANGE;
+	}
+
+	max_sdu[tc] = val;
+
+	return 0;
+}
+
+static int taprio_parse_tc_entries(struct Qdisc *sch,
+				   struct nlattr *opt,
+				   struct netlink_ext_ack *extack)
+{
+	struct taprio_sched *q = qdisc_priv(sch);
+	struct net_device *dev = qdisc_dev(sch);
+	u32 max_sdu[TC_QOPT_MAX_QUEUE];
+	unsigned long seen_tcs = 0;
+	struct nlattr *n;
+	int tc, rem;
+	int err = 0;
+
+	for (tc = 0; tc < TC_QOPT_MAX_QUEUE; tc++)
+		max_sdu[tc] = q->max_sdu[tc];
+
+	nla_for_each_nested(n, opt, rem) {
+		if (nla_type(n) != TCA_TAPRIO_ATTR_TC_ENTRY)
+			continue;
+
+		err = taprio_parse_tc_entry(sch, n, max_sdu, &seen_tcs, extack);
+		if (err)
+			goto out;
+	}
+
+	for (tc = 0; tc < TC_QOPT_MAX_QUEUE; tc++) {
+		q->max_sdu[tc] = max_sdu[tc];
+		if (max_sdu[tc])
+			q->max_frm_len[tc] = max_sdu[tc] + dev->hard_header_len;
+		else
+			q->max_frm_len[tc] = U32_MAX; /* never oversized */
+	}
+
+out:
+	return err;
+}
+
 static int taprio_mqprio_cmp(const struct net_device *dev,
 			     const struct tc_mqprio_qopt *mqprio)
 {
@@ -1445,6 +1561,10 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt,
 	if (err < 0)
 		return err;
 
+	err = taprio_parse_tc_entries(sch, opt, extack);
+	if (err)
+		return err;
+
 	new_admin = kzalloc(sizeof(*new_admin), GFP_KERNEL);
 	if (!new_admin) {
 		NL_SET_ERR_MSG(extack, "Not enough memory for a new schedule");
@@ -1825,6 +1945,33 @@ static int dump_schedule(struct sk_buff *msg,
 	return -1;
 }
 
+static int taprio_dump_tc_entries(struct taprio_sched *q, struct sk_buff *skb)
+{
+	struct nlattr *n;
+	int tc;
+
+	for (tc = 0; tc < TC_MAX_QUEUE; tc++) {
+		n = nla_nest_start(skb, TCA_TAPRIO_ATTR_TC_ENTRY);
+		if (!n)
+			return -EMSGSIZE;
+
+		if (nla_put_u32(skb, TCA_TAPRIO_TC_ENTRY_INDEX, tc))
+			goto nla_put_failure;
+
+		if (nla_put_u32(skb, TCA_TAPRIO_TC_ENTRY_MAX_SDU,
+				q->max_sdu[tc]))
+			goto nla_put_failure;
+
+		nla_nest_end(skb, n);
+	}
+
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(skb, n);
+	return -EMSGSIZE;
+}
+
 static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
 	struct taprio_sched *q = qdisc_priv(sch);
@@ -1863,6 +2010,9 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb)
 	    nla_put_u32(skb, TCA_TAPRIO_ATTR_TXTIME_DELAY, q->txtime_delay))
 		goto options_error;
 
+	if (taprio_dump_tc_entries(q, skb))
+		goto options_error;
+
 	if (oper && dump_schedule(skb, oper))
 		goto options_error;