[PATCH net-next 5/7] net: mscc: ocelot: add support for mqprio offload

[Vladimir Oltean]

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@xxxxxxx>
Reviewed-by: Ferenc Fejes <fejes@xxxxxxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
---
Diff vs
https://lore.kernel.org/netdev/20230220122343.1156614-11-vladimir.oltean@xxxxxxx/:
none.

 drivers/net/dsa/ocelot/felix_vsc9959.c |  9 +++++
 drivers/net/ethernet/mscc/ocelot.c     | 50 ++++++++++++++++++++++++++
 include/soc/mscc/ocelot.h              |  4 +++
 3 files changed, 63 insertions(+)

diff --git a/drivers/net/dsa/ocelot/felix_vsc9959.c b/drivers/net/dsa/ocelot/felix_vsc9959.c
index 478893c06f56..66ec2740e3cb 100644
--- a/drivers/net/dsa/ocelot/felix_vsc9959.c
+++ b/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:
diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index 1502bb2c8ea7..8dc5fb1bc61b 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/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];
diff --git a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h
index ee8d43dc5c06..9596c79e9223 100644
--- a/include/soc/mscc/ocelot.h
+++ b/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,
-- 
2.34.1