Re: [PATCH net-next v3 1/2] net: dsa: mt7530: factor out bridge join/leave logic

[Wojciech Drewek <wojciech.drewek@intel.com>]

On 18.06.2024 09:17, Matthias Schiffer wrote:
> As preparation for implementing bridge port isolation, move the logic to
> add and remove bits in the port matrix into a new helper
> mt7530_update_port_member(), which is called from
> mt7530_port_bridge_join() and mt7530_port_bridge_leave().
> 
> Another part of the preparation is using dsa_port_offloads_bridge_dev()
> instead of dsa_port_offloads_bridge() to check for bridge membership, as
> we don't have a struct dsa_bridge in mt7530_port_bridge_flags().
> 
> The port matrix setting is slightly streamlined, now always first setting
> the mt7530_port's pm field and then writing the port matrix from that
> field into the hardware register, instead of duplicating the bit
> manipulation for both the struct field and the register.
> 
> mt7530_port_bridge_join() was previously using |= to update the port
> matrix with the port bitmap, which was unnecessary, as pm would only
> have the CPU port set before joining a bridge; a simple assignment can
> be used for both joining and leaving (and will also work when individual
> bits are added/removed in port_bitmap with regard to the previous port
> matrix, which is what happens with port isolation).
> 
> No functional change intended.
> 
> Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
> ---

Nice cleanup :)
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>

> 
> v2: no changes
> v3: addressed overlooked review comments:
> - Ran clang-format on the patch
> - Restored code comment
> - Extended commit message
> 
> Thanks for the clang-format pointer - last time I tried that on kernel
> code (years ago), it was rather underwhelming, but it seems it has
> improved a lot.
> 
>  drivers/net/dsa/mt7530.c | 105 ++++++++++++++++++---------------------
>  1 file changed, 48 insertions(+), 57 deletions(-)
> 
> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> index 598434d8d6e4..9ce27ce07d77 100644
> --- a/drivers/net/dsa/mt7530.c
> +++ b/drivers/net/dsa/mt7530.c
> @@ -1302,6 +1302,52 @@ mt7530_stp_state_set(struct dsa_switch *ds, int port, u8 state)
>  		   FID_PST(FID_BRIDGED, stp_state));
>  }
>  
> +static void mt7530_update_port_member(struct mt7530_priv *priv, int port,
> +				      const struct net_device *bridge_dev,
> +				      bool join) __must_hold(&priv->reg_mutex)
> +{
> +	struct dsa_port *dp = dsa_to_port(priv->ds, port), *other_dp;
> +	struct mt7530_port *p = &priv->ports[port], *other_p;
> +	struct dsa_port *cpu_dp = dp->cpu_dp;
> +	u32 port_bitmap = BIT(cpu_dp->index);
> +	int other_port;
> +
> +	dsa_switch_for_each_user_port(other_dp, priv->ds) {
> +		other_port = other_dp->index;
> +		other_p = &priv->ports[other_port];
> +
> +		if (dp == other_dp)
> +			continue;
> +
> +		/* Add/remove this port to/from the port matrix of the other
> +		 * ports in the same bridge. If the port is disabled, port
> +		 * matrix is kept and not being setup until the port becomes
> +		 * enabled.
> +		 */
> +		if (!dsa_port_offloads_bridge_dev(other_dp, bridge_dev))
> +			continue;
> +
> +		if (join) {
> +			other_p->pm |= PCR_MATRIX(BIT(port));
> +			port_bitmap |= BIT(other_port);
> +		} else {
> +			other_p->pm &= ~PCR_MATRIX(BIT(port));
> +		}
> +
> +		if (other_p->enable)
> +			mt7530_rmw(priv, MT7530_PCR_P(other_port),
> +				   PCR_MATRIX_MASK, other_p->pm);
> +	}
> +
> +	/* Add/remove the all other ports to this port matrix. For !join
> +	 * (leaving the bridge), only the CPU port will remain in the port matrix
> +	 * of this port.
> +	 */
> +	p->pm = PCR_MATRIX(port_bitmap);
> +	if (priv->ports[port].enable)
> +		mt7530_rmw(priv, MT7530_PCR_P(port), PCR_MATRIX_MASK, p->pm);
> +}
> +
>  static int
>  mt7530_port_pre_bridge_flags(struct dsa_switch *ds, int port,
>  			     struct switchdev_brport_flags flags,
> @@ -1345,39 +1391,11 @@ mt7530_port_bridge_join(struct dsa_switch *ds, int port,
>  			struct dsa_bridge bridge, bool *tx_fwd_offload,
>  			struct netlink_ext_ack *extack)
>  {
> -	struct dsa_port *dp = dsa_to_port(ds, port), *other_dp;
> -	struct dsa_port *cpu_dp = dp->cpu_dp;
> -	u32 port_bitmap = BIT(cpu_dp->index);
>  	struct mt7530_priv *priv = ds->priv;
>  
>  	mutex_lock(&priv->reg_mutex);
>  
> -	dsa_switch_for_each_user_port(other_dp, ds) {
> -		int other_port = other_dp->index;
> -
> -		if (dp == other_dp)
> -			continue;
> -
> -		/* Add this port to the port matrix of the other ports in the
> -		 * same bridge. If the port is disabled, port matrix is kept
> -		 * and not being setup until the port becomes enabled.
> -		 */
> -		if (!dsa_port_offloads_bridge(other_dp, &bridge))
> -			continue;
> -
> -		if (priv->ports[other_port].enable)
> -			mt7530_set(priv, MT7530_PCR_P(other_port),
> -				   PCR_MATRIX(BIT(port)));
> -		priv->ports[other_port].pm |= PCR_MATRIX(BIT(port));
> -
> -		port_bitmap |= BIT(other_port);
> -	}
> -
> -	/* Add the all other ports to this port matrix. */
> -	if (priv->ports[port].enable)
> -		mt7530_rmw(priv, MT7530_PCR_P(port),
> -			   PCR_MATRIX_MASK, PCR_MATRIX(port_bitmap));
> -	priv->ports[port].pm |= PCR_MATRIX(port_bitmap);
> +	mt7530_update_port_member(priv, port, bridge.dev, true);
>  
>  	/* Set to fallback mode for independent VLAN learning */
>  	mt7530_rmw(priv, MT7530_PCR_P(port), PCR_PORT_VLAN_MASK,
> @@ -1478,38 +1496,11 @@ static void
>  mt7530_port_bridge_leave(struct dsa_switch *ds, int port,
>  			 struct dsa_bridge bridge)
>  {
> -	struct dsa_port *dp = dsa_to_port(ds, port), *other_dp;
> -	struct dsa_port *cpu_dp = dp->cpu_dp;
>  	struct mt7530_priv *priv = ds->priv;
>  
>  	mutex_lock(&priv->reg_mutex);
>  
> -	dsa_switch_for_each_user_port(other_dp, ds) {
> -		int other_port = other_dp->index;
> -
> -		if (dp == other_dp)
> -			continue;
> -
> -		/* Remove this port from the port matrix of the other ports
> -		 * in the same bridge. If the port is disabled, port matrix
> -		 * is kept and not being setup until the port becomes enabled.
> -		 */
> -		if (!dsa_port_offloads_bridge(other_dp, &bridge))
> -			continue;
> -
> -		if (priv->ports[other_port].enable)
> -			mt7530_clear(priv, MT7530_PCR_P(other_port),
> -				     PCR_MATRIX(BIT(port)));
> -		priv->ports[other_port].pm &= ~PCR_MATRIX(BIT(port));
> -	}
> -
> -	/* Set the cpu port to be the only one in the port matrix of
> -	 * this port.
> -	 */
> -	if (priv->ports[port].enable)
> -		mt7530_rmw(priv, MT7530_PCR_P(port), PCR_MATRIX_MASK,
> -			   PCR_MATRIX(BIT(cpu_dp->index)));
> -	priv->ports[port].pm = PCR_MATRIX(BIT(cpu_dp->index));
> +	mt7530_update_port_member(priv, port, bridge.dev, false);
>  
>  	/* When a port is removed from the bridge, the port would be set up
>  	 * back to the default as is at initial boot which is a VLAN-unaware