Re: [PATCH net-next 2/2] net: dsa: mv88e6xxx: Only allow LAG offload on supported hardware

[Vladimir Oltean <olteanv@gmail.com>]

On Fri, Jan 15, 2021 at 11:58:34AM +0100, Tobias Waldekranz wrote:
> There are chips that do have Global 2 registers, and therefore trunk
                       ~~
                       do not
> mapping/mask tables are not available. Additionally Global 2 register
> support is build-time optional, so we have to make sure that it is
> compiled in.
> 
> Fixes: 57e661aae6a8 ("net: dsa: mv88e6xxx: Link aggregation support")
> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
> ---
>  drivers/net/dsa/mv88e6xxx/chip.c | 4 ++++
>  drivers/net/dsa/mv88e6xxx/chip.h | 9 +++++++++
>  2 files changed, 13 insertions(+)
> 
> diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
> index dcb1726b68cc..c48d166c2a70 100644
> --- a/drivers/net/dsa/mv88e6xxx/chip.c
> +++ b/drivers/net/dsa/mv88e6xxx/chip.c
> @@ -5385,9 +5385,13 @@ static bool mv88e6xxx_lag_can_offload(struct dsa_switch *ds,
>  				      struct net_device *lag,
>  				      struct netdev_lag_upper_info *info)
>  {
> +	struct mv88e6xxx_chip *chip = ds->priv;
>  	struct dsa_port *dp;
>  	int id, members = 0;
>  
> +	if (!mv88e6xxx_has_lag(chip))
> +		return false;
> +
>  	id = dsa_lag_id(ds->dst, lag);
>  	if (id < 0 || id >= ds->num_lag_ids)
>  		return false;
> diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
> index 3543055bcb51..333b4fab5aa2 100644
> --- a/drivers/net/dsa/mv88e6xxx/chip.h
> +++ b/drivers/net/dsa/mv88e6xxx/chip.h
> @@ -662,6 +662,15 @@ static inline bool mv88e6xxx_has_pvt(struct mv88e6xxx_chip *chip)
>  	return chip->info->pvt;
>  }
>  
> +static inline bool mv88e6xxx_has_lag(struct mv88e6xxx_chip *chip)
> +{
> +#if (defined(CONFIG_NET_DSA_MV88E6XXX_GLOBAL2))
> +	return chip->info->global2_addr != 0;
> +#else
> +	return false;
> +#endif
> +}
> +

Should we also report ds->num_lag_ids = 0 if !mv88e6xxx_has_lag()?

>  static inline unsigned int mv88e6xxx_num_databases(struct mv88e6xxx_chip *chip)
>  {
>  	return chip->info->num_databases;
> -- 
> 2.17.1
>