[net-next RFC PATCH] net: phylink: add .pcs_link_down PCS OP

[Christian Marangi <ansuelsmth@gmail.com>]

Permit for PCS driver to define specific operation to torn 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 before .mac_link_down to torn 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>
---
 drivers/net/phy/phylink.c | 8 ++++++++
 include/linux/phylink.h   | 2 ++
 2 files changed, 10 insertions(+)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index c7f867b361dd..6605ee3670fb 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -927,6 +927,12 @@ 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)
@@ -1566,6 +1572,8 @@ static void phylink_link_down(struct phylink *pl)
 
 	phylink_deactivate_lpi(pl);
 
+	phylink_pcs_link_down(pl->pcs);
+
 	pl->mac_ops->mac_link_down(pl->config, pl->act_link_an_mode,
 				   pl->cur_interface);
 	phylink_info(pl, "Link is Down\n");
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index 30659b615fca..73172c398dd6 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -484,6 +484,7 @@ 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: torn 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
@@ -511,6 +512,7 @@ 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);
-- 
2.50.0