From: David Thompson <davthompson@nvidia.com>
Date: Fri, 2 Sep 2022 16:42:47 +0000 (-0400)
Subject: mlxbf_gige: clear MDIO gateway lock after read
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=030e0688b6b2732b31d3b918f2cc0c17f959d615;p=linux.git

mlxbf_gige: clear MDIO gateway lock after read

[ 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>
---

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 f979ba7e5effc..caa4380ada138 100644
--- a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_mdio.c
+++ b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_mdio.c
@@ -178,6 +178,9 @@ 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;
 }
 
@@ -201,6 +204,9 @@ static int mlxbf_gige_mdio_write(struct mii_bus *bus, int phy_add,
 	ret = readl_poll_timeout_atomic(priv->mdio_io + MLXBF_GIGE_MDIO_GW_OFFSET,
 					temp, !(temp & MLXBF_GIGE_MDIO_GW_BUSY_MASK), 100, 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;
 }