[SRU][F:linux-bluefield][PATCH v1 1/1] UBUNTU: SAUCE: mlxbf_gige: clear MDIO gateway lock after read

[David Thompson]

BugLink: https://bugs.launchpad.net/bugs/1989495

The MDIO gateway (GW) lock in BlueField-2 GIGE logic is
set after read.  This patch adds logic to make sure the
lock is always cleared at the end of each MDIO transaction.

Reviewed-by: Asmaa Mnebhi <asmaa at nvidia.com>
Signed-off-by: David Thompson <davthompson at nvidia.com>
---
 drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_mdio.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_mdio.c b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_mdio.c
index 6c8a4a529645..b7363c6c3e2d 100644
--- a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_mdio.c
+++ b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_mdio.c
@@ -117,6 +117,9 @@ static int mlxbf_gige_mdio_read(struct mii_bus *bus, int phy_add, int phy_reg)
 	/* Only return ad bits of the gw register */
 	ret &= MLXBF_GIGE_MDIO_GW_AD_MASK;
 
+	/* The MDIO lock is set on read. To release it, clear gw register */
+	writel(0, priv->mdio_io + MLXBF_GIGE_MDIO_GW_OFFSET);
+
 	return ret;
 }
 
@@ -141,6 +144,9 @@ static int mlxbf_gige_mdio_write(struct mii_bus *bus, int phy_add,
 					temp, !(temp & MLXBF_GIGE_MDIO_GW_BUSY_MASK),
 					5, 1000000);
 
+	/* The MDIO lock is set on read. To release it, clear gw register */
+	writel(0, priv->mdio_io + MLXBF_GIGE_MDIO_GW_OFFSET);
+
 	return ret;
 }
 
-- 
2.30.1