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From:   Tobias Waldekranz <tobias@waldekranz.com>
To:     davem@davemloft.net, kuba@kernel.org
Cc:     Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        Jiri Pirko <jiri@resnulli.us>,
        Ivan Vecera <ivecera@redhat.com>,
        Roopa Prabhu <roopa@nvidia.com>,
        Nikolay Aleksandrov <nikolay@nvidia.com>,
        Russell King <linux@armlinux.org.uk>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, bridge@lists.linux-foundation.org
Subject: [RFC net-next 9/9] net: dsa: mv88e6xxx: MST Offloading
Date:   Wed, 16 Feb 2022 14:29:34 +0100
Message-Id: <20220216132934.1775649-10-tobias@waldekranz.com>
In-Reply-To: <20220216132934.1775649-1-tobias@waldekranz.com>
References: <20220216132934.1775649-1-tobias@waldekranz.com>
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Allocate a SID in the STU for each MSTID in use by a bridge and handle
the mapping of MSTIDs to VLANs using the SID field of each VTU entry.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 169 +++++++++++++++++++++++++++++++
 drivers/net/dsa/mv88e6xxx/chip.h |  13 +++
 2 files changed, 182 insertions(+)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 39cf1bae161e..7d9ef041252d 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1817,6 +1817,128 @@ static int mv88e6xxx_stu_setup(struct mv88e6xxx_chip *chip)
 	return mv88e6xxx_stu_loadpurge(chip, &stu);
 }
 
+static int mv88e6xxx_sid_new(struct mv88e6xxx_chip *chip, u8 *sid)
+{
+	DECLARE_BITMAP(busy, MV88E6XXX_N_SID) = { 0 };
+	struct mv88e6xxx_mst *mst;
+
+	set_bit(0, busy);
+
+	list_for_each_entry(mst, &chip->msts, node) {
+		set_bit(mst->stu.sid, busy);
+	}
+
+	*sid = find_first_zero_bit(busy, MV88E6XXX_N_SID);
+
+	return (*sid >= mv88e6xxx_max_sid(chip)) ? -ENOSPC : 0;
+}
+
+static int mv88e6xxx_sid_put(struct mv88e6xxx_chip *chip, u8 sid)
+{
+	struct mv88e6xxx_mst *mst, *tmp;
+	int err = 0;
+
+	list_for_each_entry_safe(mst, tmp, &chip->msts, node) {
+		if (mst->stu.sid == sid) {
+			if (refcount_dec_and_test(&mst->refcnt)) {
+				mst->stu.valid = false;
+				err = mv88e6xxx_stu_loadpurge(chip, &mst->stu);
+				list_del(&mst->node);
+				kfree(mst);
+			}
+
+			return err;
+		}
+	}
+
+	return -ENOENT;
+}
+
+static int mv88e6xxx_sid_get(struct mv88e6xxx_chip *chip, struct net_device *br,
+			     u16 mstid, u8 *sid)
+{
+	struct mv88e6xxx_mst *mst;
+	int err;
+
+	if (!br)
+		return 0;
+
+	if (!mv88e6xxx_has_stu(chip))
+		return -EOPNOTSUPP;
+
+	list_for_each_entry(mst, &chip->msts, node) {
+		if (mst->br == br && mst->mstid == mstid) {
+			refcount_inc(&mst->refcnt);
+			*sid = mst->stu.sid;
+			return 0;
+		}
+	}
+
+	err = mv88e6xxx_sid_new(chip, sid);
+	if (err)
+		return err;
+
+	mst = kzalloc(sizeof(*mst), GFP_KERNEL);
+	if (!mst)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&mst->node);
+	refcount_set(&mst->refcnt, 1);
+	mst->br = br;
+	mst->mstid = mstid;
+	mst->stu.valid = true;
+	mst->stu.sid = *sid;
+	list_add_tail(&mst->node, &chip->msts);
+	return mv88e6xxx_stu_loadpurge(chip, &mst->stu);
+}
+
+static int mv88e6xxx_port_mst_state_set(struct dsa_switch *ds, int port,
+					const struct switchdev_mst_state *st)
+{
+	struct dsa_port *dp = dsa_to_port(ds, port);
+	struct mv88e6xxx_chip *chip = ds->priv;
+	struct mv88e6xxx_mst *mst;
+	u8 state;
+	int err;
+
+	if (!mv88e6xxx_has_stu(chip))
+		return -EOPNOTSUPP;
+
+	switch (st->state) {
+	case BR_STATE_DISABLED:
+		state = MV88E6XXX_PORT_CTL0_STATE_DISABLED;
+		break;
+	case BR_STATE_BLOCKING:
+	case BR_STATE_LISTENING:
+		state = MV88E6XXX_PORT_CTL0_STATE_BLOCKING;
+		break;
+	case BR_STATE_LEARNING:
+		state = MV88E6XXX_PORT_CTL0_STATE_LEARNING;
+		break;
+	case BR_STATE_FORWARDING:
+		state = MV88E6XXX_PORT_CTL0_STATE_FORWARDING;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	list_for_each_entry(mst, &chip->msts, node) {
+		if (mst->br == dsa_port_bridge_dev_get(dp) &&
+		    mst->mstid == st->mstid) {
+			if (mst->stu.state[port] == state)
+				return 0;
+
+			mst->stu.state[port] = state;
+			mv88e6xxx_reg_lock(chip);
+			err = mv88e6xxx_stu_loadpurge(chip, &mst->stu);
+			mv88e6xxx_reg_unlock(chip);
+			return err;
+		}
+	}
+
+	return -ENOENT;
+}
+
 static int mv88e6xxx_port_check_hw_vlan(struct dsa_switch *ds, int port,
 					u16 vid)
 {
@@ -2436,6 +2558,12 @@ static int mv88e6xxx_port_vlan_leave(struct mv88e6xxx_chip *chip,
 	if (err)
 		return err;
 
+	if (!vlan.valid) {
+		err = mv88e6xxx_sid_put(chip, vlan.sid);
+		if (err)
+			return err;
+	}
+
 	return mv88e6xxx_g1_atu_remove(chip, vlan.fid, port, false);
 }
 
@@ -2474,6 +2602,44 @@ static int mv88e6xxx_port_vlan_del(struct dsa_switch *ds, int port,
 	return err;
 }
 
+static int mv88e6xxx_vlan_mstid_set(struct dsa_switch *ds,
+				    const struct switchdev_attr *attr)
+{
+	const struct switchdev_vlan_attr *vattr = &attr->u.vlan_attr;
+	struct mv88e6xxx_chip *chip = ds->priv;
+	struct mv88e6xxx_vtu_entry vlan;
+	u8 new_sid;
+	int err;
+
+	mv88e6xxx_reg_lock(chip);
+
+	err = mv88e6xxx_vtu_get(chip, vattr->vid, &vlan);
+	if (err)
+		goto unlock;
+
+	if (!vlan.valid) {
+		err = -EINVAL;
+		goto unlock;
+	}
+
+	err = mv88e6xxx_sid_get(chip, attr->orig_dev, vattr->mstid, &new_sid);
+	if (err)
+		goto unlock;
+
+	if (vlan.sid) {
+		err = mv88e6xxx_sid_put(chip, vlan.sid);
+		if (err)
+			goto unlock;
+	}
+
+	vlan.sid = new_sid;
+	err = mv88e6xxx_vtu_loadpurge(chip, &vlan);
+
+unlock:
+	mv88e6xxx_reg_unlock(chip);
+	return err;
+}
+
 static int mv88e6xxx_port_fdb_add(struct dsa_switch *ds, int port,
 				  const unsigned char *addr, u16 vid)
 {
@@ -5996,6 +6162,7 @@ static struct mv88e6xxx_chip *mv88e6xxx_alloc_chip(struct device *dev)
 	mutex_init(&chip->reg_lock);
 	INIT_LIST_HEAD(&chip->mdios);
 	idr_init(&chip->policies);
+	INIT_LIST_HEAD(&chip->msts);
 
 	return chip;
 }
@@ -6518,10 +6685,12 @@ static const struct dsa_switch_ops mv88e6xxx_switch_ops = {
 	.port_pre_bridge_flags	= mv88e6xxx_port_pre_bridge_flags,
 	.port_bridge_flags	= mv88e6xxx_port_bridge_flags,
 	.port_stp_state_set	= mv88e6xxx_port_stp_state_set,
+	.port_mst_state_set	= mv88e6xxx_port_mst_state_set,
 	.port_fast_age		= mv88e6xxx_port_fast_age,
 	.port_vlan_filtering	= mv88e6xxx_port_vlan_filtering,
 	.port_vlan_add		= mv88e6xxx_port_vlan_add,
 	.port_vlan_del		= mv88e6xxx_port_vlan_del,
+	.vlan_mstid_set		= mv88e6xxx_vlan_mstid_set,
 	.port_fdb_add           = mv88e6xxx_port_fdb_add,
 	.port_fdb_del           = mv88e6xxx_port_fdb_del,
 	.port_fdb_dump          = mv88e6xxx_port_fdb_dump,
diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index 6d4daa24d3e5..af0f53b65689 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h
@@ -297,6 +297,16 @@ struct mv88e6xxx_region_priv {
 	enum mv88e6xxx_region_id id;
 };
 
+struct mv88e6xxx_mst {
+	struct list_head node;
+
+	refcount_t refcnt;
+	struct net_device *br;
+	u16 mstid;
+
+	struct mv88e6xxx_stu_entry stu;
+};
+
 struct mv88e6xxx_chip {
 	const struct mv88e6xxx_info *info;
 
@@ -397,6 +407,9 @@ struct mv88e6xxx_chip {
 
 	/* devlink regions */
 	struct devlink_region *regions[_MV88E6XXX_REGION_MAX];
+
+	/* Bridge MST to SID mappings */
+	struct list_head msts;
 };
 
 struct mv88e6xxx_bus_ops {
-- 
2.25.1