[RFC net-next PATCH 02/13] net: phylink: Support setting PCS link change callbacks

[Sean Anderson <sean.anderson@linux.dev>]

Support changing the link change callback, similar to how PHYs do it.
This will allow the PCS wrapper to forward link changes to the wrapped
PCS.

Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
---

 drivers/net/phy/phylink.c | 24 +++++++-----------------
 include/linux/phylink.h   | 27 ++++++++++++++++++++++-----
 2 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 69ca765485db..76ce96315c0c 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -1205,6 +1205,8 @@ static void phylink_pcs_neg_mode(struct phylink *pl, struct phylink_pcs *pcs,
 	pl->act_link_an_mode = mode;
 }
 
+static void pcs_change_callback(void *priv, bool up);
+
 static void phylink_major_config(struct phylink *pl, bool restart,
 				  const struct phylink_link_state *state)
 {
@@ -1260,10 +1262,10 @@ static void phylink_major_config(struct phylink *pl, bool restart,
 		phylink_pcs_disable(pl->pcs);
 
 		if (pl->pcs)
-			pl->pcs->phylink = NULL;
-
-		pcs->phylink = pl;
+			pl->pcs->link_change_priv = NULL;
 
+		pcs->link_change = pcs_change_callback;
+		pcs->link_change_priv = pl;
 		pl->pcs = pcs;
 	}
 
@@ -2333,25 +2335,13 @@ void phylink_mac_change(struct phylink *pl, bool up)
 }
 EXPORT_SYMBOL_GPL(phylink_mac_change);
 
-/**
- * phylink_pcs_change() - notify phylink of a change to PCS link state
- * @pcs: pointer to &struct phylink_pcs
- * @up: indicates whether the link is currently up.
- *
- * The PCS driver should call this when the state of its link changes
- * (e.g. link failure, new negotiation results, etc.) Note: it should
- * not determine "up" by reading the BMSR. If in doubt about the link
- * state at interrupt time, then pass true if pcs_get_state() returns
- * the latched link-down state, otherwise pass false.
- */
-void phylink_pcs_change(struct phylink_pcs *pcs, bool up)
+static void pcs_change_callback(void *priv, bool up)
 {
-	struct phylink *pl = pcs->phylink;
+	struct phylink *pl = priv;
 
 	if (pl)
 		phylink_link_changed(pl, up, "pcs");
 }
-EXPORT_SYMBOL_GPL(phylink_pcs_change);
 
 static irqreturn_t phylink_link_handler(int irq, void *data)
 {
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index 1f5773ab5660..a16282ae746d 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -441,7 +441,8 @@ struct phylink_pcs_ops;
  * @supported_interfaces: describing which PHY_INTERFACE_MODE_xxx
  *                        are supported by this PCS.
  * @ops: a pointer to the &struct phylink_pcs_ops structure
- * @phylink: pointer to &struct phylink_config
+ * @link_change: callback for when the link changes
+ * @link_change_priv: first argument to @link_change
  * @poll: poll the PCS for link changes
  * @rxc_always_on: The MAC driver requires the reference clock
  *                 to always be on. Standalone PCS drivers which
@@ -451,13 +452,14 @@ struct phylink_pcs_ops;
  * This structure is designed to be embedded within the PCS private data,
  * and will be passed between phylink and the PCS.
  *
- * The @phylink member is private to phylink and must not be touched by
- * the PCS driver.
+ * @link_change, @link_change_priv, and @rxc_always_on will be filled in by
+ * phylink.
  */
 struct phylink_pcs {
 	DECLARE_PHY_INTERFACE_MASK(supported_interfaces);
 	const struct phylink_pcs_ops *ops;
-	struct phylink *phylink;
+	void (*link_change)(void *priv, bool up);
+	void *link_change_priv;
 	bool poll;
 	bool rxc_always_on;
 };
@@ -699,7 +701,22 @@ int phylink_set_fixed_link(struct phylink *,
 			   const struct phylink_link_state *);
 
 void phylink_mac_change(struct phylink *, bool up);
-void phylink_pcs_change(struct phylink_pcs *, bool up);
+/**
+ * phylink_pcs_change() - notify phylink of a change to PCS link state
+ * @pcs: pointer to &struct phylink_pcs
+ * @up: indicates whether the link is currently up.
+ *
+ * The PCS driver should call this when the state of its link changes
+ * (e.g. link failure, new negotiation results, etc.) Note: it should
+ * not determine "up" by reading the BMSR. If in doubt about the link
+ * state at interrupt time, then pass true if pcs_get_state() returns
+ * the latched link-down state, otherwise pass false.
+ */
+static inline void phylink_pcs_change(struct phylink_pcs *pcs, bool up)
+{
+	if (pcs->link_change)
+		pcs->link_change(pcs->link_change_priv, up);
+}
 
 int phylink_pcs_pre_init(struct phylink *pl, struct phylink_pcs *pcs);
 
-- 
2.35.1.1320.gc452695387.dirty