[PATCH 4.4 46/53] net/fsl: treat fsl,erratum-a011043

Greg Kroah-Hartman
2020-02-03T16:22:27Z

From: Madalin Bucur <madalin.bucur@oss.nxp.com>

[ Upstream commit 1d3ca681b9d9575ccf696ebc2840a1ebb1fd4074 ]

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@oss.nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 7b8fe866f6038..a15b4a97c172d 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);
@@ -277,6 +279,9 @@ static int xgmac_mdio_probe(struct platform_device *pdev)
else
priv->is_little_endian = false;

+ 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");
--
2.20.1