net: mscc: ocelot: add support for mqprio offload

This doesn't apply anything to hardware and in general doesn't do
anything that the software variant doesn't do, except for checking that
there isn't more than 1 TXQ per TC (TXQs for a DSA switch are a dubious
concept anyway). The reason we add this is to be able to parse one more
field added to struct tc_mqprio_qopt_offload, namely preemptible_tcs.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ferenc Fejes <fejes@inf.elte.hu>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/ocelot/felix_vsc9959.c

@@ -1612,6 +1612,13 @@ static int vsc9959_qos_port_cbs_set(struct dsa_switch *ds, int port,
 static int vsc9959_qos_query_caps(struct tc_query_caps_base *base)
 {
 	switch (base->type) {
+	case TC_SETUP_QDISC_MQPRIO: {
+		struct tc_mqprio_caps *caps = base->caps;
+
+		caps->validate_queue_counts = true;
+
+		return 0;
+	}
 	case TC_SETUP_QDISC_TAPRIO: {
 		struct tc_taprio_caps *caps = base->caps;
 
@@ -1635,6 +1642,8 @@ static int vsc9959_port_setup_tc(struct dsa_switch *ds, int port,
 		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_MQPRIO:
+		return ocelot_port_mqprio(ocelot, port, type_data);
 	case TC_SETUP_QDISC_CBS:
 		return vsc9959_qos_port_cbs_set(ds, port, type_data);
 	default:

drivers/net/ethernet/mscc/ocelot.c

@@ -8,6 +8,7 @@
 #include <linux/if_bridge.h>
 #include <linux/iopoll.h>
 #include <linux/phy/phy.h>
+#include <net/pkt_sched.h>
 #include <soc/mscc/ocelot_hsio.h>
 #include <soc/mscc/ocelot_vcap.h>
 #include "ocelot.h"
@@ -2699,6 +2700,55 @@ void ocelot_port_mirror_del(struct ocelot *ocelot, int from, bool ingress)
 }
 EXPORT_SYMBOL_GPL(ocelot_port_mirror_del);
 
+static void ocelot_port_reset_mqprio(struct ocelot *ocelot, int port)
+{
+	struct net_device *dev = ocelot->ops->port_to_netdev(ocelot, port);
+
+	netdev_reset_tc(dev);
+}
+
+int ocelot_port_mqprio(struct ocelot *ocelot, int port,
+		       struct tc_mqprio_qopt_offload *mqprio)
+{
+	struct net_device *dev = ocelot->ops->port_to_netdev(ocelot, port);
+	struct netlink_ext_ack *extack = mqprio->extack;
+	struct tc_mqprio_qopt *qopt = &mqprio->qopt;
+	int num_tc = qopt->num_tc;
+	int tc, err;
+
+	if (!num_tc) {
+		ocelot_port_reset_mqprio(ocelot, port);
+		return 0;
+	}
+
+	err = netdev_set_num_tc(dev, num_tc);
+	if (err)
+		return err;
+
+	for (tc = 0; tc < num_tc; tc++) {
+		if (qopt->count[tc] != 1) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "Only one TXQ per TC supported");
+			return -EINVAL;
+		}
+
+		err = netdev_set_tc_queue(dev, tc, 1, qopt->offset[tc]);
+		if (err)
+			goto err_reset_tc;
+	}
+
+	err = netif_set_real_num_tx_queues(dev, num_tc);
+	if (err)
+		goto err_reset_tc;
+
+	return 0;
+
+err_reset_tc:
+	ocelot_port_reset_mqprio(ocelot, port);
+	return err;
+}
+EXPORT_SYMBOL_GPL(ocelot_port_mqprio);
+
 void ocelot_init_port(struct ocelot *ocelot, int port)
 {
 	struct ocelot_port *ocelot_port = ocelot->ports[port];

include/soc/mscc/ocelot.h

@@ -11,6 +11,8 @@
 #include <linux/regmap.h>
 #include <net/dsa.h>
 
+struct tc_mqprio_qopt_offload;
+
 /* Port Group IDs (PGID) are masks of destination ports.
  *
  * For L2 forwarding, the switch performs 3 lookups in the PGID table for each
@@ -1154,6 +1156,8 @@ int ocelot_port_set_mm(struct ocelot *ocelot, int port,
 		       struct netlink_ext_ack *extack);
 int ocelot_port_get_mm(struct ocelot *ocelot, int port,
 		       struct ethtool_mm_state *state);
+int ocelot_port_mqprio(struct ocelot *ocelot, int port,
+		       struct tc_mqprio_qopt_offload *mqprio);
 
 #if IS_ENABLED(CONFIG_BRIDGE_MRP)
 int ocelot_mrp_add(struct ocelot *ocelot, int port,