Re: [PATCH net-next 2/3] net: stmmac: xgmac: Add C45 PHY support in the MDIO callbacks

Add the support for C45 PHYs in the MDIO callbacks for XGMAC. This was
tested using Synopsys DesignWare XPCS.

Signed-off-by: Jose Abreu <Jose.Abreu@synopsys.com>

---
Cc: Giuseppe Cavallaro <redacted>
Cc: Alexandre Torgue <redacted>
Cc: Jose Abreu <redacted>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: netdev@vger.kernel.org
Cc: linux-stm32@st-md-mailman.stormreply.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c | 47 +++++++++++++++++++++--
 1 file changed, 43 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
index 40c42637ad75..143bffd28acf 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c

@@ -41,6 +41,29 @@
 #define MII_XGMAC_BUSY			BIT(22)
 #define MII_XGMAC_MAX_C22ADDR		3
 #define MII_XGMAC_C22P_MASK		GENMASK(MII_XGMAC_MAX_C22ADDR, 0)
+#define MII_XGMAC_PA_SHIFT		16
+#define MII_XGMAC_DA_SHIFT		21
+
+static int stmmac_xgmac2_c45_format(struct stmmac_priv *priv, int phyaddr,
+				    int phyreg, u32 *hw_addr)
+{
+	unsigned int mii_data = priv->hw->mii.data;
+	u32 tmp;
+
+	/* Wait until any existing MII operation is complete */
+	if (readl_poll_timeout(priv->ioaddr + mii_data, tmp,
+			       !(tmp & MII_XGMAC_BUSY), 100, 10000))
+		return -EBUSY;