[PATCH 5.19 114/207] mlxbf_gige: clear MDIO gateway lock after read

Greg Kroah-Hartman
2022-09-26T12:03:27Z

From: David Thompson <davthompson@nvidia.com>

[ Upstream commit 182447b12144b7be9b63a273d27c5a11bd54960a ]

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.

Fixes: f92e1869d74e ("Add Mellanox BlueField Gigabit Ethernet driver")
Reviewed-by: Asmaa Mnebhi <asmaa@nvidia.com>
Signed-off-by: David Thompson <davthompson@nvidia.com>
Link: https://lore.kernel.org/r/20220902164247.19862-1-davthompson@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 85155cd9405c..4aeb927c3715 100644
--- a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_mdio.c
+++ b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_mdio.c
@@ -179,6 +179,9 @@ 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;
}

@@ -203,6 +206,9 @@ 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;
}

--
2.35.1