net: add helpers to resolve negotiated flow control

Add a couple of helpers to resolve negotiated flow control. Two helpers
are provided:

- linkmode_resolve_pause() which takes the link partner and local
  advertisements, and decodes whether we should enable TX or RX pause
  at the MAC. This is useful outside of phylib, e.g. in phylink.
- phy_get_pause(), which returns the TX/RX enablement status for the
  current negotiation results of the PHY.

This allows us to centralise the flow control resolution, rather than
spreading it around.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 26 insertions, 0 deletions

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 28e3c5c0e3c3..651eff5127df 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -2414,6 +2414,32 @@ bool phy_validate_pause(struct phy_device *phydev,
 }
 EXPORT_SYMBOL(phy_validate_pause);
 
+/**
+ * phy_get_pause - resolve negotiated pause modes
+ * @phydev: phy_device struct
+ * @tx_pause: pointer to bool to indicate whether transmit pause should be
+ * enabled.
+ * @rx_pause: pointer to bool to indicate whether receive pause should be
+ * enabled.
+ *
+ * Resolve and return the flow control modes according to the negotiation
+ * result. This includes checking that we are operating in full duplex mode.
+ * See linkmode_resolve_pause() for further details.
+ */
+void phy_get_pause(struct phy_device *phydev, bool *tx_pause, bool *rx_pause)
+{
+	if (phydev->duplex != DUPLEX_FULL) {
+		*tx_pause = false;
+		*rx_pause = false;
+		return;
+	}
+
+	return linkmode_resolve_pause(phydev->advertising,
+				      phydev->lp_advertising,
+				      tx_pause, rx_pause);
+}
+EXPORT_SYMBOL(phy_get_pause);
+
 static bool phy_drv_supports_irq(struct phy_driver *phydrv)
 {
 	return phydrv->config_intr && phydrv->ack_interrupt;