net: phylink: add support for polling MAC PCS

Some MAC PCS blocks are unable to provide interrupts when their status
changes. As we already have support in phylink for polling status, use
this to provide a hook for MACs to enable polling mode.

The patch idea was picked up from Russell King's suggestion on the macb
phylink patch thread here [0] but the implementation was changed.
Instead of introducing a new phylink_start_poll() function, which would
make the implementation cumbersome for common PHYLINK implementations
for multiple types of devices, like DSA, just add a boolean property to
the phylink_config structure, which is just as backwards-compatible.

https://lkml.org/lkml/2019/12/16/603

Suggested-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/networking/sfp-phylink.rst b/Documentation/networking/sfp-phylink.rst
index a5e00a159d214e8d9b81f7ab767a1cc951cd15ef..d753a309f9d120bb58ef5c5e996209278889ec90 100644 (file)
--- a/Documentation/networking/sfp-phylink.rst
+++ b/Documentation/networking/sfp-phylink.rst
@@ -251,7 +251,8 @@ this documentation.
        phylink_mac_change(priv->phylink, link_is_up);
 
     where ``link_is_up`` is true if the link is currently up or false
-    otherwise.
+    otherwise. If a MAC is unable to provide these interrupts, then
+    it should set ``priv->phylink_config.pcs_poll = true;`` in step 9.
 
 11. Verify that the driver does not call::
 

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 88686e0f9ae14d37b1cbe3fa53f3eb562d23011a..af914a8842bd8602e41bb8bcc74117118d91a621 100644 (file)
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -1022,7 +1022,8 @@ void phylink_start(struct phylink *pl)
                if (irq <= 0)
                        mod_timer(&pl->link_poll, jiffies + HZ);
        }
-       if (pl->cfg_link_an_mode == MLO_AN_FIXED && pl->get_fixed_state)
+       if ((pl->cfg_link_an_mode == MLO_AN_FIXED && pl->get_fixed_state) ||
+           pl->config->pcs_poll)
                mod_timer(&pl->link_poll, jiffies + HZ);
        if (pl->phydev)
                phy_start(pl->phydev);

diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index fed5488e3c75857e5b391ab5a87f4b3a8c1bf97c..523209e70947309a167e34d6a76759ff783f7a55 100644 (file)
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -63,10 +63,12 @@ enum phylink_op_type {
  * struct phylink_config - PHYLINK configuration structure
  * @dev: a pointer to a struct device associated with the MAC
  * @type: operation type of PHYLINK instance
+ * @pcs_poll: MAC PCS cannot provide link change interrupt
  */
 struct phylink_config {
        struct device *dev;
        enum phylink_op_type type;
+       bool pcs_poll;
 };
 
 /**