net: introduce a helper to determine whether to use in-band autoneg

Certain serial SERDES protocols like 1000base-x, 2500base-x, SGMII,
USXGMII can operate either in a mode where the PHY (be it on-board or
inside an SFP module) passes the link parameters (speed, duplex, pause)
to the MAC through in-band through control words standardized by IEEE
802.3 clause 37, or in a mode where the MAC must configure (force) its
link parameters based on information obtained out-of-band (MDIO reads,
guesswork etc).

In Linux, the OF node property named "managed" is parsed by the phylink
framework, and the convention is that if a driver uses phylink, then the
presence of this property means that in-band autoneg should be enabled,
otherwise it shouldn't.

To be compatible with the OF node bindings of drivers that use phylink
in Linux, introduce parsing support for this property in U-Boot too.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/core/of_extra.c b/drivers/core/of_extra.c
index 632a1c2..59ce917 100644
--- a/drivers/core/of_extra.c
+++ b/drivers/core/of_extra.c
@@ -155,3 +155,15 @@ bool ofnode_phy_is_fixed_link(ofnode eth_node, ofnode *phy_node)
 
 	return true;
 }
+
+bool ofnode_eth_uses_inband_aneg(ofnode eth_node)
+{
+	bool inband_aneg = false;
+	const char *managed;
+
+	managed = ofnode_read_string(eth_node, "managed");
+	if (managed && !strcmp(managed, "in-band-status"))
+		inband_aneg = true;
+
+	return inband_aneg;
+}