[PATCH net-next] net: stmmac: fix EEE supportable interfaces

[Russell King (Oracle)]

According to the dwmac v3.74a databook, only MII, GMII and RGMII dwmac
interface modes are supported for EEE. Restrict EEE to these modes, or
the modules supported by a PCS other than the GMAC's integrated PCS.

Signed-off-by: Russell King (Oracle) <rmk+kernel at armlinux.org.uk>
---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c  | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 82375d34ad57..89ded359a9fe 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1374,9 +1374,21 @@ static int stmmac_phylink_setup(struct stmmac_priv *priv)
 				 pcs->supported_interfaces);
 
 	if (priv->dma_cap.eee) {
-		/* Assume all supported interfaces also support LPI */
-		memcpy(config->lpi_interfaces, config->supported_interfaces,
-		       sizeof(config->lpi_interfaces));
+		/* The GMAC 3.74a databook states that EEE is only supported
+		 * in MII, GMII, and RGMII interfaces.
+		 */
+		__set_bit(PHY_INTERFACE_MODE_MII, config->lpi_interfaces);
+		__set_bit(PHY_INTERFACE_MODE_GMII, config->lpi_interfaces);
+		phy_interface_set_rgmii(config->lpi_interfaces);
+
+		/* If we have a non-integrated PCS, assume that it is connected
+		 * to the GMAC using GMII or another EEE compatible interface,
+		 * and thus all PCS-supported interfaces support LPI.
+		 */
+		if (pcs)
+			phy_interface_or(config->lpi_interfaces,
+					 config->lpi_interfaces,
+					 pcs->supported_interfaces);
 
 		/* All full duplex speeds above 100Mbps are supported */
 		config->lpi_capabilities = ~(MAC_1000FD - 1) | MAC_100FD;
-- 
2.47.3