[PATCH net-next v11 09/12] net: phylink: add .pcs_link_down PCS OP

[Christian Marangi <ansuelsmth@gmail.com>]

Permit for PCS driver to define specific operation to tear down the link
between the MAC and the PCS.

This might be needed for some PCS that reset counter or require special
reset to correctly work if the link needs to be restored later.

On phylink_link_down() call, the additional phylink_pcs_link_down() will
be called after .mac_link_down to tear down the link.

PCS driver will need to define .pcs_link_down to make use of this.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 drivers/net/phy/phylink.c |  9 +++++++++
 include/linux/phylink.h   | 12 ++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 69d4f6675db0..2e8d11573e3a 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -982,6 +982,12 @@ static void phylink_pcs_link_up(struct phylink_pcs *pcs, unsigned int neg_mode,
 		pcs->ops->pcs_link_up(pcs, neg_mode, interface, speed, duplex);
 }
 
+static void phylink_pcs_link_down(struct phylink_pcs *pcs)
+{
+	if (pcs && pcs->ops->pcs_link_down)
+		pcs->ops->pcs_link_down(pcs);
+}
+
 static void phylink_pcs_disable_eee(struct phylink_pcs *pcs)
 {
 	if (pcs && pcs->ops->pcs_disable_eee)
@@ -1683,6 +1689,9 @@ static void phylink_link_down(struct phylink *pl)
 
 	pl->mac_ops->mac_link_down(pl->config, pl->act_link_an_mode,
 				   pl->cur_interface);
+
+	phylink_pcs_link_down(pl->pcs);
+
 	phylink_info(pl, "Link is Down\n");
 }
 
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index ca9dfc142388..ea554c0d41f8 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -528,6 +528,7 @@ struct phylink_pcs {
  * @pcs_an_restart: restart 802.3z BaseX autonegotiation.
  * @pcs_link_up: program the PCS for the resolved link configuration
  *               (where necessary).
+ * @pcs_link_down: tear down link between MAC and PCS.
  * @pcs_disable_eee: optional notification to PCS that EEE has been disabled
  *		     at the MAC.
  * @pcs_enable_eee: optional notification to PCS that EEE will be enabled at
@@ -555,6 +556,7 @@ struct phylink_pcs_ops {
 	void (*pcs_an_restart)(struct phylink_pcs *pcs);
 	void (*pcs_link_up)(struct phylink_pcs *pcs, unsigned int neg_mode,
 			    phy_interface_t interface, int speed, int duplex);
+	void (*pcs_link_down)(struct phylink_pcs *pcs);
 	void (*pcs_disable_eee)(struct phylink_pcs *pcs);
 	void (*pcs_enable_eee)(struct phylink_pcs *pcs);
 	int (*pcs_pre_init)(struct phylink_pcs *pcs);
@@ -690,6 +692,16 @@ void pcs_an_restart(struct phylink_pcs *pcs);
 void pcs_link_up(struct phylink_pcs *pcs, unsigned int neg_mode,
 		 phy_interface_t interface, int speed, int duplex);
 
+/**
+ * pcs_link_down() - tear down link between MAC and PCS
+ * @pcs: a pointer to a &struct phylink_pcs.
+ *
+ * This call will be made just after mac_link_down() to inform the PCS the
+ * link has gone down. PCS should be configured to stop processing packets
+ * for transmission and reception.
+ */
+void pcs_link_down(struct phylink_pcs *pcs);
+
 /**
  * pcs_disable_eee() - Disable EEE at the PCS
  * @pcs: a pointer to a &struct phylink_pcs
-- 
2.53.0