Merge branch 'qca8k-fixes'

Marek Behún says:

====================
net: dsa: qca8k: fix qca8k driver for Turris 1.x

this is v2 of
  https://lore.kernel.org/netdev/20231002104612.21898-1-kabel@kernel.org/

Changes since v1:
- fixed a typo in commit message noticed by Simon Horman
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 2 deletions

diff --git a/drivers/net/dsa/qca/qca8k-8xxx.c b/drivers/net/dsa/qca/qca8k-8xxx.c
index de1dc22cf68317..4ce68e655a632d 100644
--- a/drivers/net/dsa/qca/qca8k-8xxx.c
+++ b/drivers/net/dsa/qca/qca8k-8xxx.c
@@ -505,8 +505,8 @@ qca8k_bulk_read(void *ctx, const void *reg_buf, size_t reg_len,
 		void *val_buf, size_t val_len)
 {
 	int i, count = val_len / sizeof(u32), ret;
-	u32 reg = *(u32 *)reg_buf & U16_MAX;
 	struct qca8k_priv *priv = ctx;
+	u32 reg = *(u16 *)reg_buf;
 
 	if (priv->mgmt_master &&
 	    !qca8k_read_eth(priv, reg, val_buf, val_len))
@@ -527,8 +527,8 @@ qca8k_bulk_gather_write(void *ctx, const void *reg_buf, size_t reg_len,
 			const void *val_buf, size_t val_len)
 {
 	int i, count = val_len / sizeof(u32), ret;
-	u32 reg = *(u32 *)reg_buf & U16_MAX;
 	struct qca8k_priv *priv = ctx;
+	u32 reg = *(u16 *)reg_buf;
 	u32 *val = (u32 *)val_buf;
 
 	if (priv->mgmt_master &&
@@ -666,6 +666,15 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
 		goto err_read_skb;
 	}
 
+	/* It seems that accessing the switch's internal PHYs via management
+	 * packets still uses the MDIO bus within the switch internally, and
+	 * these accesses can conflict with external MDIO accesses to other
+	 * devices on the MDIO bus.
+	 * We therefore need to lock the MDIO bus onto which the switch is
+	 * connected.
+	 */
+	mutex_lock(&priv->bus->mdio_lock);
+
 	/* Actually start the request:
 	 * 1. Send mdio master packet
 	 * 2. Busy Wait for mdio master command
@@ -678,6 +687,7 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
 	mgmt_master = priv->mgmt_master;
 	if (!mgmt_master) {
 		mutex_unlock(&mgmt_eth_data->mutex);
+		mutex_unlock(&priv->bus->mdio_lock);
 		ret = -EINVAL;
 		goto err_mgmt_master;
 	}
@@ -765,6 +775,7 @@ exit:
 				    QCA8K_ETHERNET_TIMEOUT);
 
 	mutex_unlock(&mgmt_eth_data->mutex);
+	mutex_unlock(&priv->bus->mdio_lock);
 
 	return ret;