Re: [PATCH RFC net-next 12/13] net: phylink: add struct phylink_pcs

[Vladimir Oltean <olteanv@gmail.com>]

Hi Russell,

On Tue, 30 Jun 2020 at 17:29, Russell King <rmk+kernel@armlinux.org.uk> wrote:
>
> Add a way for MAC PCS to have private data while keeping independence
> from struct phylink_config, which is used for the MAC itself. We need
> this independence as we will have stand-alone code for PCS that is
> independent of the MAC.  Introduce struct phylink_pcs, which is
> designed to be embedded in a driver private data structure.
>
> This structure does not include a mdio_device as there are PCS
> implementations such as the Marvell DSA and network drivers where this
> is not necessary.
>
> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
> ---
>  drivers/net/phy/phylink.c | 25 ++++++++++++++++------
>  include/linux/phylink.h   | 45 ++++++++++++++++++++++++++-------------
>  2 files changed, 48 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
> index a31a00fb4974..fbc8591b474b 100644
> --- a/drivers/net/phy/phylink.c
> +++ b/drivers/net/phy/phylink.c
> @@ -43,6 +43,7 @@ struct phylink {
>         const struct phylink_mac_ops *mac_ops;
>         const struct phylink_pcs_ops *pcs_ops;
>         struct phylink_config *config;
> +       struct phylink_pcs *pcs;
>         struct device *dev;
>         unsigned int old_link_state:1;
>
> @@ -427,7 +428,7 @@ static void phylink_mac_pcs_an_restart(struct phylink *pl)
>             phy_interface_mode_is_8023z(pl->link_config.interface) &&
>             phylink_autoneg_inband(pl->cur_link_an_mode)) {
>                 if (pl->pcs_ops)
> -                       pl->pcs_ops->pcs_an_restart(pl->config);
> +                       pl->pcs_ops->pcs_an_restart(pl->pcs);
>                 else
>                         pl->mac_ops->mac_an_restart(pl->config);
>         }
> @@ -453,7 +454,7 @@ static void phylink_change_interface(struct phylink *pl, bool restart,
>         phylink_mac_config(pl, state);
>
>         if (pl->pcs_ops) {
> -               err = pl->pcs_ops->pcs_config(pl->config, pl->cur_link_an_mode,
> +               err = pl->pcs_ops->pcs_config(pl->pcs, pl->cur_link_an_mode,
>                                               state->interface,
>                                               state->advertising,
>                                               !!(pl->link_config.pause &
> @@ -533,7 +534,7 @@ static void phylink_mac_pcs_get_state(struct phylink *pl,
>         state->link = 1;
>
>         if (pl->pcs_ops)
> -               pl->pcs_ops->pcs_get_state(pl->config, state);
> +               pl->pcs_ops->pcs_get_state(pl->pcs, state);
>         else
>                 pl->mac_ops->mac_pcs_get_state(pl->config, state);
>  }
> @@ -604,7 +605,7 @@ static void phylink_link_up(struct phylink *pl,
>         pl->cur_interface = link_state.interface;
>
>         if (pl->pcs_ops && pl->pcs_ops->pcs_link_up)
> -               pl->pcs_ops->pcs_link_up(pl->config, pl->cur_link_an_mode,
> +               pl->pcs_ops->pcs_link_up(pl->pcs, pl->cur_link_an_mode,
>                                          pl->cur_interface,
>                                          link_state.speed, link_state.duplex);
>
> @@ -863,11 +864,19 @@ struct phylink *phylink_create(struct phylink_config *config,
>  }
>  EXPORT_SYMBOL_GPL(phylink_create);
>
> -void phylink_add_pcs(struct phylink *pl, const struct phylink_pcs_ops *ops)
> +/**
> + * phylink_set_pcs() - set the current PCS for phylink to use
> + * @pl: a pointer to a &struct phylink returned from phylink_create()
> + * @pcs: a pointer to the &struct phylink_pcs
> + *
> + * Bind the MAC PCS to phylink.
> + */
> +void phylink_set_pcs(struct phylink *pl, struct phylink_pcs *pcs)
>  {
> -       pl->pcs_ops = ops;
> +       pl->pcs = pcs;
> +       pl->pcs_ops = pcs->ops;
>  }
> -EXPORT_SYMBOL_GPL(phylink_add_pcs);
> +EXPORT_SYMBOL_GPL(phylink_set_pcs);
>
>  /**
>   * phylink_destroy() - cleanup and destroy the phylink instance
> @@ -1212,6 +1221,8 @@ void phylink_start(struct phylink *pl)
>                 break;
>         case MLO_AN_INBAND:
>                 poll |= pl->config->pcs_poll;
> +               if (pl->pcs)
> +                       poll |= pl->pcs->poll;

Do we see a need for yet another way to request phylink to poll the
PCS for link status?

>                 break;
>         }
>         if (poll)
> diff --git a/include/linux/phylink.h b/include/linux/phylink.h
> index 2f1315f32113..057f78263a46 100644
> --- a/include/linux/phylink.h
> +++ b/include/linux/phylink.h
> @@ -321,6 +321,21 @@ void mac_link_up(struct phylink_config *config, struct phy_device *phy,
>                  int speed, int duplex, bool tx_pause, bool rx_pause);
>  #endif
>
> +struct phylink_pcs_ops;
> +
> +/**
> + * struct phylink_pcs - PHYLINK PCS instance
> + * @ops: a pointer to the &struct phylink_pcs_ops structure
> + * @poll: poll the PCS for link changes
> + *
> + * This structure is designed to be embedded within the PCS private data,
> + * and will be passed between phylink and the PCS.
> + */
> +struct phylink_pcs {
> +       const struct phylink_pcs_ops *ops;
> +       bool poll;
> +};
> +
>  /**
>   * struct phylink_pcs_ops - MAC PCS operations structure.
>   * @pcs_get_state: read the current MAC PCS link state from the hardware.
> @@ -330,21 +345,21 @@ void mac_link_up(struct phylink_config *config, struct phy_device *phy,
>   *               (where necessary).
>   */
>  struct phylink_pcs_ops {
> -       void (*pcs_get_state)(struct phylink_config *config,
> +       void (*pcs_get_state)(struct phylink_pcs *pcs,
>                               struct phylink_link_state *state);
> -       int (*pcs_config)(struct phylink_config *config, unsigned int mode,
> +       int (*pcs_config)(struct phylink_pcs *pcs, unsigned int mode,
>                           phy_interface_t interface,
>                           const unsigned long *advertising,
>                           bool permit_pause_to_mac);
> -       void (*pcs_an_restart)(struct phylink_config *config);
> -       void (*pcs_link_up)(struct phylink_config *config, unsigned int mode,
> +       void (*pcs_an_restart)(struct phylink_pcs *pcs);
> +       void (*pcs_link_up)(struct phylink_pcs *pcs, unsigned int mode,
>                             phy_interface_t interface, int speed, int duplex);
>  };
>
>  #if 0 /* For kernel-doc purposes only. */
>  /**
>   * pcs_get_state() - Read the current inband link state from the hardware
> - * @config: a pointer to a &struct phylink_config.
> + * @pcs: a pointer to a &struct phylink_pcs.
>   * @state: a pointer to a &struct phylink_link_state.
>   *
>   * Read the current inband link state from the MAC PCS, reporting the
> @@ -357,12 +372,12 @@ struct phylink_pcs_ops {
>   * When present, this overrides mac_pcs_get_state() in &struct
>   * phylink_mac_ops.
>   */
> -void pcs_get_state(struct phylink_config *config,
> +void pcs_get_state(struct phylink_pcs *pcs,
>                    struct phylink_link_state *state);
>
>  /**
>   * pcs_config() - Configure the PCS mode and advertisement
> - * @config: a pointer to a &struct phylink_config.
> + * @pcs: a pointer to a &struct phylink_pcs.
>   * @mode: one of %MLO_AN_FIXED, %MLO_AN_PHY, %MLO_AN_INBAND.
>   * @interface: interface mode to be used
>   * @advertising: adertisement ethtool link mode mask
> @@ -382,21 +397,21 @@ void pcs_get_state(struct phylink_config *config,
>   *
>   * For most 10GBASE-R, there is no advertisement.
>   */
> -int (*pcs_config)(struct phylink_config *config, unsigned int mode,
> -                 phy_interface_t interface, const unsigned long *advertising);
> +int pcs_config(struct phylink_pcs *pcs, unsigned int mode,
> +              phy_interface_t interface, const unsigned long *advertising);
>
>  /**
>   * pcs_an_restart() - restart 802.3z BaseX autonegotiation
> - * @config: a pointer to a &struct phylink_config.
> + * @pcs: a pointer to a &struct phylink_pcs.
>   *
>   * When PCS ops are present, this overrides mac_an_restart() in &struct
>   * phylink_mac_ops.
>   */
> -void (*pcs_an_restart)(struct phylink_config *config);
> +void pcs_an_restart(struct phylink_pcs *pcs);
>
>  /**
>   * pcs_link_up() - program the PCS for the resolved link configuration
> - * @config: a pointer to a &struct phylink_config.
> + * @pcs: a pointer to a &struct phylink_pcs.
>   * @mode: link autonegotiation mode
>   * @interface: link &typedef phy_interface_t mode
>   * @speed: link speed
> @@ -407,14 +422,14 @@ void (*pcs_an_restart)(struct phylink_config *config);
>   * mode without in-band AN needs to be manually configured for the link
>   * and duplex setting. Otherwise, this should be a no-op.
>   */
> -void (*pcs_link_up)(struct phylink_config *config, unsigned int mode,
> -                   phy_interface_t interface, int speed, int duplex);
> +void pcs_link_up(struct phylink_pcs *pcs, unsigned int mode,
> +                phy_interface_t interface, int speed, int duplex);
>  #endif
>
>  struct phylink *phylink_create(struct phylink_config *, struct fwnode_handle *,
>                                phy_interface_t iface,
>                                const struct phylink_mac_ops *mac_ops);
> -void phylink_add_pcs(struct phylink *, const struct phylink_pcs_ops *ops);
> +void phylink_set_pcs(struct phylink *, struct phylink_pcs *pcs);
>  void phylink_destroy(struct phylink *);
>
>  int phylink_connect_phy(struct phylink *, struct phy_device *);
> --
> 2.20.1
>

Thank you,
-Vladimir