On Sat, 10 Oct 2020 18:41:14 +0300 Ido Schimmel wrote:
> From: Danielle Ratson <[email protected]>
>
> 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.
What's the use for this in practical terms? Isn't the lane count
basically implied by the module that gets plugged in?
> +/* Lanes, 1, 2, 4 or 8. */
> +#define ETHTOOL_LANES_1 1
> +#define ETHTOOL_LANES_2 2
> +#define ETHTOOL_LANES_4 4
> +#define ETHTOOL_LANES_8 8
Not an extremely useful set of defines, not sure Michal would agree.
> +#define ETHTOOL_LANES_UNKNOWN 0
> struct link_mode_info {
> int speed;
> + int lanes;
why signed?
> u8 duplex;
> };
> @@ -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 },
NLA_POLICY_VALIDATE_FN(), not sure why the types for this
validation_type are limited.. Johannes, just an abundance of caution?
> + } else if (!lsettings->autoneg) {
> + /* If autoneg is off and lanes parameter is not passed from
> user,
> + * set the lanes parameter to UNKNOWN.
> + */
> + ksettings->lanes = ETHTOOL_LANES_UNKNOWN;
you assume UNKNOWN is zero by doing !lanes in auto_linkmodes -
that's inconsistent.
> + }
> +
> ret = ethnl_update_bitset(ksettings->link_modes.advertising,
> __ETHTOOL_LINK_MODE_MASK_NBITS,
> tb[ETHTOOL_A_LINKMODES_OURS], link_mode_names,
