On Tue, Mar 01, 2022 at 11:03:21AM +0100, Tobias Waldekranz wrote:
> 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 <[email protected]>
> ---
>  drivers/net/dsa/mv88e6xxx/chip.c | 178 +++++++++++++++++++++++++++++++
>  drivers/net/dsa/mv88e6xxx/chip.h |  13 +++
>  2 files changed, 191 insertions(+)
> 
> diff --git a/drivers/net/dsa/mv88e6xxx/chip.c 
> b/drivers/net/dsa/mv88e6xxx/chip.c
> index c14a62aa6a6c..4fb4ec1dff79 100644
> --- a/drivers/net/dsa/mv88e6xxx/chip.c
> +++ b/drivers/net/dsa/mv88e6xxx/chip.c
> @@ -1818,6 +1818,137 @@ 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);

It is interesting what to do if this fails. Possibly not this, because
the entry remains in hardware but not in software.

> +                             list_del(&mst->node);
> +                             kfree(mst);
> +                     }
> +
> +                     return err;
> +             }
> +     }
> +
> +     return -ENOENT;
> +}
> +
> +static int mv88e6xxx_sid_get(struct mv88e6xxx_chip *chip, struct net_device 
> *br,
> +                          u16 msti, u8 *sid)
> +{
> +     struct mv88e6xxx_mst *mst;
> +     int err, i;
> +
> +     if (!br)
> +             return 0;

Is this condition possible?

> +
> +     if (!mv88e6xxx_has_stu(chip))
> +             return -EOPNOTSUPP;
> +
> +     list_for_each_entry(mst, &chip->msts, node) {
> +             if (mst->br == br && mst->msti == msti) {
> +                     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;

This leaks the new SID.

> +
> +     INIT_LIST_HEAD(&mst->node);
> +     refcount_set(&mst->refcnt, 1);
> +     mst->br = br;
> +     mst->msti = msti;
> +     mst->stu.valid = true;
> +     mst->stu.sid = *sid;
> +
> +     /* The bridge starts out all ports in the disabled state. But
> +      * a STU state of disabled means to go by the port-global
> +      * state. So we set all user port's initial state to blocking,
> +      * to match the bridge's behavior.
> +      */
> +     for (i = 0; i < mv88e6xxx_num_ports(chip); i++)
> +             mst->stu.state[i] = dsa_is_user_port(chip->ds, i) ?
> +                     MV88E6XXX_PORT_CTL0_STATE_BLOCKING :
> +                     MV88E6XXX_PORT_CTL0_STATE_DISABLED;
> +
> +     list_add_tail(&mst->node, &chip->msts);
> +     return mv88e6xxx_stu_loadpurge(chip, &mst->stu);

And this doesn't behave too well on failure (the MSTID exists in
software but not in hardware).

> +}
> +
> +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:
> +     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->msti == st->msti) {
> +                     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)
>  {
> @@ -2437,6 +2568,12 @@ static int mv88e6xxx_port_vlan_leave(struct 
> mv88e6xxx_chip *chip,
>       if (err)
>               return err;
>  
> +     if (!vlan.valid && vlan.sid) {
> +             err = mv88e6xxx_sid_put(chip, vlan.sid);
> +             if (err)
> +                     return err;
> +     }
> +
>       return mv88e6xxx_g1_atu_remove(chip, vlan.fid, port, false);
>  }
>  
> @@ -2482,6 +2619,44 @@ static int mv88e6xxx_port_vlan_del(struct dsa_switch 
> *ds, int port,
>       return err;
>  }
>  
> +static int mv88e6xxx_vlan_msti_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->msti, &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);

Maybe you could move mv88e6xxx_sid_put() after this succeeds?

> +
> +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,
>                                 struct dsa_db db)
> @@ -6008,6 +6183,7 @@ 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;
>  }
> @@ -6540,10 +6716,12 @@ 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_msti_set          = mv88e6xxx_vlan_msti_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..6a0b66354e1d 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 msti;
> +
> +     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
> 

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