net: phylink: use legacy_pre_march2020

Use the legacy flag to indicate whether we should operate in legacy
mode. This allows us to stop using the presence of a PCS as an
indicator to the age of the phylink user, and make PCS presence
optional.

Legacy mode involves:
1) calling mac_config() whenever the link comes up
2) calling mac_config() whenever the inband advertisement changes,
   possibly followed by a call to mac_an_restart()
3) making use of mac_an_restart()
4) making use of mac_pcs_get_state()

All the above functionality was moved to a seperate "PCS" block of
operations in March 2020.

Update the documents to indicate that the differences that this flag
makes.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 8e3861f09b4f09e2da832c9c41ddcfbbc4bc7eb3..e47f2baf4b076cac00e4bfd89077bc0cca47f906 100644 (file)
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -742,7 +742,7 @@ static void phylink_mac_pcs_an_restart(struct phylink *pl)
            phylink_autoneg_inband(pl->cur_link_an_mode)) {
                if (pl->pcs_ops)
                        pl->pcs_ops->pcs_an_restart(pl->pcs);
-               else
+               else if (pl->config->legacy_pre_march2020)
                        pl->mac_ops->mac_an_restart(pl->config);
        }
 }
@@ -803,7 +803,7 @@ static int phylink_change_inband_advert(struct phylink *pl)
        if (test_bit(PHYLINK_DISABLE_STOPPED, &pl->phylink_disable_state))
                return 0;
 
-       if (!pl->pcs_ops) {
+       if (!pl->pcs_ops && pl->config->legacy_pre_march2020) {
                /* Legacy method */
                phylink_mac_config(pl, &pl->link_config);
                phylink_mac_pcs_an_restart(pl);
@@ -854,7 +854,8 @@ static void phylink_mac_pcs_get_state(struct phylink *pl,
 
        if (pl->pcs_ops)
                pl->pcs_ops->pcs_get_state(pl->pcs, state);
-       else if (pl->mac_ops->mac_pcs_get_state)
+       else if (pl->mac_ops->mac_pcs_get_state &&
+                pl->config->legacy_pre_march2020)
                pl->mac_ops->mac_pcs_get_state(pl->config, state);
        else
                state->link = 0;
@@ -1048,12 +1049,11 @@ static void phylink_resolve(struct work_struct *w)
                        }
                        phylink_major_config(pl, false, &link_state);
                        pl->link_config.interface = link_state.interface;
-               } else if (!pl->pcs_ops) {
+               } else if (!pl->pcs_ops && pl->config->legacy_pre_march2020) {
                        /* The interface remains unchanged, only the speed,
                         * duplex or pause settings have changed. Call the
                         * old mac_config() method to configure the MAC/PCS
-                        * only if we do not have a PCS installed (an
-                        * unconverted user.)
+                        * only if we do not have a legacy MAC driver.
                         */
                        phylink_mac_config(pl, &link_state);
                }

diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index d005b8e360480f6a362f8933ce65f036ffc56513..a2f266cc34429c2e1513671fa51fe6edad008241 100644 (file)
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -190,6 +190,10 @@ void validate(struct phylink_config *config, unsigned long *supported,
  * negotiation completion state in @state->an_complete, and link up state
  * in @state->link. If possible, @state->lp_advertising should also be
  * populated.
+ *
+ * Note: This is a legacy method. This function will not be called unless
+ * legacy_pre_march2020 is set in &struct phylink_config and there is no
+ * PCS attached.
  */
 void mac_pcs_get_state(struct phylink_config *config,
                       struct phylink_link_state *state);
@@ -230,6 +234,15 @@ int mac_prepare(struct phylink_config *config, unsigned int mode,
  * guaranteed to be correct, and so any mac_config() implementation must
  * never reference these fields.
  *
+ * Note: For legacy March 2020 drivers (drivers with legacy_pre_march2020 set
+ * in their &phylnk_config and which don't have a PCS), this function will be
+ * called on each link up event, and to also change the in-band advert. For
+ * non-legacy drivers, it will only be called to reconfigure the MAC for a
+ * "major" change in e.g. interface mode. It will not be called for changes
+ * in speed, duplex or pause modes or to change the in-band advertisement.
+ * In any case, it is strongly preferred that speed, duplex and pause settings
+ * are handled in the mac_link_up() method and not in this method.
+ *
  * (this requires a rewrite - please refer to mac_link_up() for situations
  *  where the PCS and MAC are not tightly integrated.)
  *
@@ -314,6 +327,10 @@ int mac_finish(struct phylink_config *config, unsigned int mode,
 /**
  * mac_an_restart() - restart 802.3z BaseX autonegotiation
  * @config: a pointer to a &struct phylink_config.
+ *
+ * Note: This is a legacy method. This function will not be called unless
+ * legacy_pre_march2020 is set in &struct phylink_config and there is no
+ * PCS attached.
  */
 void mac_an_restart(struct phylink_config *config);