On Wed, 6 Jan 2021 15:06:16 +0200 Danielle Ratson wrote:
> From: Danielle Ratson <daniel...@nvidia.com>
>
> Currently, when auto negotiation is on, the user can advertise all the
> linkmodes which correspond to a specific speed, but does not have a
> similar selector for the number of lanes. This is significant when a
> specific speed can be achieved using different number of lanes. For
> example, 2x50 or 4x25.
>
> Add 'ETHTOOL_A_LINKMODES_LANES' attribute and expand 'struct
> ethtool_link_settings' with lanes field in order to implement a new
> lanes-selector that will enable the user to advertise a specific number
> of lanes as well.
>
> When auto negotiation is off, lanes parameter can be forced only if the
> driver supports it. Add a capability bit in 'struct ethtool_ops' that
> allows ethtool know if the driver can handle the lanes parameter when
> auto negotiation is off, so if it does not, an error message will be
> returned when trying to set lanes.
> @@ -420,6 +423,7 @@ struct ethtool_pause_stats {
> * of the generic netdev features interface.
> */
> struct ethtool_ops {
> + u32 capabilities;
An appropriately named bitfield seems better. Alternatively maybe let
the driver specify which lane counts it can accept?
And please remember to add the kdoc.
> u32 supported_coalesce_params;
> void (*get_drvinfo)(struct net_device *, struct ethtool_drvinfo *);
> int (*get_regs_len)(struct net_device *);
> @@ -274,16 +277,17 @@ const struct nla_policy ethnl_linkmodes_set_policy[] = {
> [ETHTOOL_A_LINKMODES_SPEED] = { .type = NLA_U32 },
> [ETHTOOL_A_LINKMODES_DUPLEX] = { .type = NLA_U8 },
> [ETHTOOL_A_LINKMODES_MASTER_SLAVE_CFG] = { .type = NLA_U8 },
> + [ETHTOOL_A_LINKMODES_LANES] = { .type = NLA_U32 },
Please set the min and max for the policy, so userspace can at least
see that part.
> +static bool ethnl_validate_lanes_cfg(u32 cfg)
> +{
> + switch (cfg) {
> + case 1:
> + case 2:
> + case 4:
> + case 8:
> + return true;
And with the policy checking min and max this can be turned into
a simple is_power_of_2() call.
> + }
> +
> + return false;
> +}
