[PATCH net-next 11/14] net: phylink: in-band pause mode advertisement update for PCS

[Russell King <rmk+kernel@armlinux.org.uk>]

Re-code the pause in-band advertisement update in light of the addition
of PCS support, so that we perform the minimum required; only the PCS
configuration function needs to be called in this case, followed by the
request to trigger a restart of negotiation if the programmed
advertisement changed.

We need to change the pcs_config() signature to pass whether resolved
pause should be passed to the MAC for setups such as mvneta and mvpp2
where doing so overrides the MAC manual flow controls.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 drivers/net/phy/phylink.c | 55 ++++++++++++++++++++++++++++++++++++---
 include/linux/phylink.h   |  7 +++--
 2 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 452d509803ca..84a426401102 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -441,7 +441,9 @@ static void phylink_pcs_config(struct phylink *pl, bool force_restart,
 	if (pl->pcs_ops && pl->pcs_ops->pcs_config(pl->config,
 						   pl->cur_link_an_mode,
 						   state->interface,
-						   state->advertising))
+						   state->advertising,
+						   !!(pl->link_config.pause &
+						      MLO_PAUSE_AN)))
 		restart = true;
 
 	phylink_mac_config(pl, state);
@@ -450,6 +452,49 @@ static void phylink_pcs_config(struct phylink *pl, bool force_restart,
 		phylink_mac_pcs_an_restart(pl);
 }
 
+/*
+ * Reconfigure for a change of inband advertisement.
+ * If we have a separate PCS, we only need to call its pcs_config() method,
+ * and then restart AN if it indicates something changed. Otherwise, we do
+ * the full MAC reconfiguration.
+ */
+static int phylink_change_inband_advert(struct phylink *pl)
+{
+	int ret;
+
+	if (test_bit(PHYLINK_DISABLE_STOPPED, &pl->phylink_disable_state))
+		return 0;
+
+	if (!pl->pcs_ops) {
+		/* Legacy method */
+		phylink_mac_config(pl, &pl->link_config);
+		phylink_mac_pcs_an_restart(pl);
+		return 0;
+	}
+
+	phylink_dbg(pl, "%s: mode=%s/%s adv=%*pb pause=%02x\n", __func__,
+		    phylink_an_mode_str(pl->cur_link_an_mode),
+		    phy_modes(pl->link_config.interface),
+		    __ETHTOOL_LINK_MODE_MASK_NBITS, pl->link_config.advertising,
+		    pl->link_config.pause);
+
+	/* Modern PCS-based method; update the advert at the PCS, and
+	 * restart negotiation if the pcs_config() helper indicates that
+	 * the programmed advertisement has changed.
+	 */
+	ret = pl->pcs_ops->pcs_config(pl->config, pl->cur_link_an_mode,
+				      pl->link_config.interface,
+				      pl->link_config.advertising,
+				      !!(pl->link_config.pause & MLO_PAUSE_AN));
+	if (ret < 0)
+		return ret;
+
+	if (ret > 0)
+		phylink_mac_pcs_an_restart(pl);
+
+	return 0;
+}
+
 static void phylink_mac_pcs_get_state(struct phylink *pl,
 				      struct phylink_link_state *state)
 {
@@ -1524,9 +1569,11 @@ int phylink_ethtool_set_pauseparam(struct phylink *pl,
 
 	config->pause = pause_state;
 
-	if (!pl->phydev && !test_bit(PHYLINK_DISABLE_STOPPED,
-				     &pl->phylink_disable_state))
-		phylink_pcs_config(pl, true, &pl->link_config);
+	/* Update our in-band advertisement, triggering a renegotiation if
+	 * the advertisement changed.
+	 */
+	if (!pl->phydev)
+		phylink_change_inband_advert(pl);
 
 	mutex_unlock(&pl->state_mutex);
 
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index b32b8b45421b..d9913d8e6b91 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -286,7 +286,8 @@ struct phylink_pcs_ops {
 			      struct phylink_link_state *state);
 	int (*pcs_config)(struct phylink_config *config, unsigned int mode,
 			  phy_interface_t interface,
-			  const unsigned long *advertising);
+			  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,
 			    phy_interface_t interface, int speed, int duplex);
@@ -317,9 +318,11 @@ void pcs_get_state(struct phylink_config *config,
  * @mode: one of %MLO_AN_FIXED, %MLO_AN_PHY, %MLO_AN_INBAND.
  * @interface: interface mode to be used
  * @advertising: adertisement ethtool link mode mask
+ * @permit_pause_to_mac: permit forwarding pause resolution to MAC
  *
  * Configure the PCS for the operating mode, the interface mode, and set
- * the advertisement mask.
+ * the advertisement mask. @permit_pause_to_mac indicates whether the
+ * hardware may forward the pause mode resolution to the MAC.
  *
  * When operating in %MLO_AN_INBAND, inband should always be enabled,
  * otherwise inband should be disabled.
-- 
2.20.1