netdev - [PATCH net 3/3] net/fsl: treat fsl,erratum-a011043

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Message-Id: <1579699229-5948-4-git-send-email-madalin.bucur@oss.nxp.com>
Date:   Wed, 22 Jan 2020 15:20:29 +0200
From:   Madalin Bucur <madalin.bucur@....nxp.com>
To:     davem@...emloft.net, netdev@...r.kernel.org
Cc:     robh+dt@...nel.org, mark.rutland@....com,
        devicetree@...r.kernel.org,
        Madalin Bucur <madalin.bucur@....nxp.com>
Subject: [PATCH net 3/3] net/fsl: treat fsl,erratum-a011043

When fsl,erratum-a011043 is set, adjust for erratum A011043:
MDIO reads to internal PCS registers may result in having
the MDIO_CFG[MDIO_RD_ER] bit set, even when there is no
error and read data (MDIO_DATA[MDIO_DATA]) is correct.
Software may get false read error when reading internal
PCS registers through MDIO. As a workaround, all internal
MDIO accesses should ignore the MDIO_CFG[MDIO_RD_ER] bit.

Signed-off-by: Madalin Bucur <madalin.bucur@....nxp.com>
---
 drivers/net/ethernet/freescale/xgmac_mdio.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/xgmac_mdio.c b/drivers/net/ethernet/freescale/xgmac_mdio.c
index e03b30c60dcf..c82c85ef5fb3 100644
--- a/drivers/net/ethernet/freescale/xgmac_mdio.c
+++ b/drivers/net/ethernet/freescale/xgmac_mdio.c
@@ -49,6 +49,7 @@ struct tgec_mdio_controller {
 struct mdio_fsl_priv {
 	struct	tgec_mdio_controller __iomem *mdio_base;
 	bool	is_little_endian;
+	bool	has_a011043;
 };
 
 static u32 xgmac_read32(void __iomem *regs,
@@ -226,7 +227,8 @@ static int xgmac_mdio_read(struct mii_bus *bus, int phy_id, int regnum)
 		return ret;
 
 	/* Return all Fs if nothing was there */
-	if (xgmac_read32(&regs->mdio_stat, endian) & MDIO_STAT_RD_ER) {
+	if ((xgmac_read32(&regs->mdio_stat, endian) & MDIO_STAT_RD_ER) &&
+	    !priv->has_a011043) {
 		dev_err(&bus->dev,
 			"Error while reading PHY%d reg at %d.%hhu\n",
 			phy_id, dev_addr, regnum);
@@ -274,6 +276,9 @@ static int xgmac_mdio_probe(struct platform_device *pdev)
 	priv->is_little_endian = of_property_read_bool(pdev->dev.of_node,
 						       "little-endian");
 
+	priv->has_a011043 = of_property_read_bool(pdev->dev.of_node,
+						  "fsl,erratum-a011043");
+
 	ret = of_mdiobus_register(bus, np);
 	if (ret) {
 		dev_err(&pdev->dev, "cannot register MDIO bus\n");
-- 
2.1.0