[PATCH net-next 01/12] net: dsa: qca8k: Move register access completion into DSA core

From: Luke Howard <hidden>
Date: 2026-07-03 07:30:39
Also in: lkml
Subsystem: networking drivers, networking [dsa], networking [general], the rest · Maintainers: Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Vladimir Oltean, Linus Torvalds

From: Andrew Lunn <andrew@lunn.ch>

When performing operations on a remote switch using Ethernet frames, a
completion is used between the sender of the request and the code
which receives the reply.

Move this completion into the DSA core, simplifying the driver.  The
initialisation and reinitialisation of the completion is now performed
in the core. Also, the conversion of milliseconds to jiffies is also
in the core.

The MIB access via left untouched because it is not a simple
request/reply protocol.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
---
 drivers/net/dsa/qca/qca8k-8xxx.c | 43 +++++++++++++++-------------------------
 drivers/net/dsa/qca/qca8k.h      |  4 ++--
 include/net/dsa.h                | 12 +++++++++++
 net/dsa/dsa.c                    | 22 ++++++++++++++++++++
 4 files changed, 52 insertions(+), 29 deletions(-)

diff --git a/drivers/net/dsa/qca/qca8k-8xxx.c b/drivers/net/dsa/qca/qca8k-8xxx.c
index 4c928983b8623..fe6fb69b6f92f 100644
--- a/drivers/net/dsa/qca/qca8k-8xxx.c
+++ b/drivers/net/dsa/qca/qca8k-8xxx.c

@@ -212,7 +212,7 @@ static void qca8k_rw_reg_ack_handler(struct dsa_switch *ds, struct sk_buff *skb)
 		}
 	}
 
-	complete(&mgmt_eth_data->rw_done);
+	dsa_inband_complete(&mgmt_eth_data->inband);
 }
 
 static struct sk_buff *qca8k_alloc_mdio_header(enum mdio_cmd cmd, u32 reg, u32 *val,

@@ -332,8 +332,6 @@ static int qca8k_read_eth(struct qca8k_priv *priv, u32 reg, u32 *val, int len)
 
 	skb->dev = priv->mgmt_conduit;
 
-	reinit_completion(&mgmt_eth_data->rw_done);
-
 	/* Increment seq_num and set it in the mdio pkt */
 	mgmt_eth_data->seq++;
 	qca8k_mdio_header_fill_seq_num(skb, mgmt_eth_data->seq);

@@ -341,8 +339,8 @@ static int qca8k_read_eth(struct qca8k_priv *priv, u32 reg, u32 *val, int len)
 
 	dev_queue_xmit(skb);
 
-	ret = wait_for_completion_timeout(&mgmt_eth_data->rw_done,
-					  QCA8K_ETHERNET_TIMEOUT);
+	ret = dsa_inband_wait_for_completion(&mgmt_eth_data->inband,
+					     QCA8K_ETHERNET_TIMEOUT);
 
 	*val = mgmt_eth_data->data[0];
 	if (len > QCA_HDR_MGMT_DATA1_LEN)

@@ -384,8 +382,6 @@ static int qca8k_write_eth(struct qca8k_priv *priv, u32 reg, u32 *val, int len)
 
 	skb->dev = priv->mgmt_conduit;
 
-	reinit_completion(&mgmt_eth_data->rw_done);
-
 	/* Increment seq_num and set it in the mdio pkt */
 	mgmt_eth_data->seq++;
 	qca8k_mdio_header_fill_seq_num(skb, mgmt_eth_data->seq);

@@ -393,8 +389,8 @@ static int qca8k_write_eth(struct qca8k_priv *priv, u32 reg, u32 *val, int len)
 
 	dev_queue_xmit(skb);
 
-	ret = wait_for_completion_timeout(&mgmt_eth_data->rw_done,
-					  QCA8K_ETHERNET_TIMEOUT);
+	ret = dsa_inband_wait_for_completion(&mgmt_eth_data->inband,
+					     QCA8K_ETHERNET_TIMEOUT);
 
 	ack = mgmt_eth_data->ack;

@@ -594,8 +590,6 @@ qca8k_phy_eth_busy_wait(struct qca8k_mgmt_eth_data *mgmt_eth_data,
 	if (!skb)
 		return -ENOMEM;
 
-	reinit_completion(&mgmt_eth_data->rw_done);
-
 	/* Increment seq_num and set it in the copy pkt */
 	mgmt_eth_data->seq++;
 	qca8k_mdio_header_fill_seq_num(skb, mgmt_eth_data->seq);

@@ -603,8 +597,8 @@ qca8k_phy_eth_busy_wait(struct qca8k_mgmt_eth_data *mgmt_eth_data,
 
 	dev_queue_xmit(skb);
 
-	ret = wait_for_completion_timeout(&mgmt_eth_data->rw_done,
-					  QCA8K_ETHERNET_TIMEOUT);
+	ret = dsa_inband_wait_for_completion(&mgmt_eth_data->inband,
+					     QCA8K_ETHERNET_TIMEOUT);
 
 	ack = mgmt_eth_data->ack;

@@ -696,8 +690,6 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
 	clear_skb->dev = mgmt_conduit;
 	write_skb->dev = mgmt_conduit;
 
-	reinit_completion(&mgmt_eth_data->rw_done);
-
 	/* Increment seq_num and set it in the write pkt */
 	mgmt_eth_data->seq++;
 	qca8k_mdio_header_fill_seq_num(write_skb, mgmt_eth_data->seq);

@@ -705,8 +697,8 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
 
 	dev_queue_xmit(write_skb);
 
-	ret = wait_for_completion_timeout(&mgmt_eth_data->rw_done,
-					  QCA8K_ETHERNET_TIMEOUT);
+	ret = dsa_inband_wait_for_completion(&mgmt_eth_data->inband,
+					     QCA8K_ETHERNET_TIMEOUT);
 
 	ack = mgmt_eth_data->ack;

@@ -733,8 +725,6 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
 	}
 
 	if (read) {
-		reinit_completion(&mgmt_eth_data->rw_done);
-
 		/* Increment seq_num and set it in the read pkt */
 		mgmt_eth_data->seq++;
 		qca8k_mdio_header_fill_seq_num(read_skb, mgmt_eth_data->seq);

@@ -742,8 +732,8 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
 
 		dev_queue_xmit(read_skb);
 
-		ret = wait_for_completion_timeout(&mgmt_eth_data->rw_done,
-						  QCA8K_ETHERNET_TIMEOUT);
+		ret = dsa_inband_wait_for_completion(&mgmt_eth_data->inband,
+						     QCA8K_ETHERNET_TIMEOUT);
 
 		ack = mgmt_eth_data->ack;

@@ -762,8 +752,6 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
 		kfree_skb(read_skb);
 	}
 exit:
-	reinit_completion(&mgmt_eth_data->rw_done);
-
 	/* Increment seq_num and set it in the clear pkt */
 	mgmt_eth_data->seq++;
 	qca8k_mdio_header_fill_seq_num(clear_skb, mgmt_eth_data->seq);

@@ -771,8 +759,8 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
 
 	dev_queue_xmit(clear_skb);
 
-	wait_for_completion_timeout(&mgmt_eth_data->rw_done,
-				    QCA8K_ETHERNET_TIMEOUT);
+	dsa_inband_wait_for_completion(&mgmt_eth_data->inband,
+				       QCA8K_ETHERNET_TIMEOUT);
 
 	mutex_unlock(&mgmt_eth_data->mutex);
 	mutex_unlock(&priv->bus->mdio_lock);

@@ -1728,7 +1716,8 @@ qca8k_get_ethtool_stats_eth(struct dsa_switch *ds, int port, u64 *data)
 	if (ret)
 		goto exit;
 
-	ret = wait_for_completion_timeout(&mib_eth_data->rw_done, QCA8K_ETHERNET_TIMEOUT);
+	ret = wait_for_completion_timeout(&mib_eth_data->rw_done,
+					  msecs_to_jiffies(QCA8K_ETHERNET_TIMEOUT));
 
 exit:
 	mutex_unlock(&mib_eth_data->mutex);

@@ -2105,7 +2094,7 @@ qca8k_sw_probe(struct mdio_device *mdiodev)
 		return -ENOMEM;
 
 	mutex_init(&priv->mgmt_eth_data.mutex);
-	init_completion(&priv->mgmt_eth_data.rw_done);
+	dsa_inband_init(&priv->mgmt_eth_data.inband);
 
 	mutex_init(&priv->mib_eth_data.mutex);
 	init_completion(&priv->mib_eth_data.rw_done);

diff --git a/drivers/net/dsa/qca/qca8k.h b/drivers/net/dsa/qca/qca8k.h
index 9563388930325..938f2c9ff0cac 100644
--- a/drivers/net/dsa/qca/qca8k.h
+++ b/drivers/net/dsa/qca/qca8k.h

@@ -16,7 +16,7 @@
 
 #define QCA8K_ETHERNET_MDIO_PRIORITY			7
 #define QCA8K_ETHERNET_PHY_PRIORITY			6
-#define QCA8K_ETHERNET_TIMEOUT				msecs_to_jiffies(5)
+#define QCA8K_ETHERNET_TIMEOUT				5
 
 #define QCA8K_NUM_PORTS					7
 #define QCA8K_NUM_CPU_PORTS				2

@@ -392,7 +392,7 @@ enum {
 };
 
 struct qca8k_mgmt_eth_data {
-	struct completion rw_done;
+	struct dsa_inband inband;
 	struct mutex mutex; /* Enforce one mdio read/write at time */
 	bool ack;
 	u32 seq;

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 8c16ef23cc102..9b0c109b3058a 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h

@@ -7,6 +7,7 @@
 #ifndef __LINUX_NET_DSA_H
 #define __LINUX_NET_DSA_H
 
+#include <linux/completion.h>
 #include <linux/if.h>
 #include <linux/if_ether.h>
 #include <linux/list.h>

@@ -1347,6 +1348,17 @@ int dsa_port_simple_hsr_join(struct dsa_switch *ds, int port,
 int dsa_port_simple_hsr_leave(struct dsa_switch *ds, int port,
 			      struct net_device *hsr);
 
+/* Perform operations on a switch by sending it request in Ethernet
+ * frames and expecting a response in a frame.
+ */
+struct dsa_inband {
+	struct completion completion;
+};
+
+void dsa_inband_init(struct dsa_inband *inband);
+void dsa_inband_complete(struct dsa_inband *inband);
+int dsa_inband_wait_for_completion(struct dsa_inband *inband, int timeout_ms);
+
 /* Keep inline for faster access in hot path */
 static inline bool netdev_uses_dsa(const struct net_device *dev)
 {

diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index 9cb732f6b1e3e..dc4e5cdb2f5b2 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c

@@ -1834,6 +1834,28 @@ int dsa_port_simple_hsr_leave(struct dsa_switch *ds, int port,
 }
 EXPORT_SYMBOL_GPL(dsa_port_simple_hsr_leave);
 
+void dsa_inband_init(struct dsa_inband *inband)
+{
+	init_completion(&inband->completion);
+}
+EXPORT_SYMBOL_GPL(dsa_inband_init);
+
+void dsa_inband_complete(struct dsa_inband *inband)
+{
+	complete(&inband->completion);
+}
+EXPORT_SYMBOL_GPL(dsa_inband_complete);
+
+int dsa_inband_wait_for_completion(struct dsa_inband *inband, int timeout_ms)
+{
+	unsigned long jiffies = msecs_to_jiffies(timeout_ms);
+
+	reinit_completion(&inband->completion);
+
+	return wait_for_completion_timeout(&inband->completion, jiffies);
+}
+EXPORT_SYMBOL_GPL(dsa_inband_wait_for_completion);
+
 static const struct dsa_stubs __dsa_stubs = {
 	.conduit_hwtstamp_validate = __dsa_conduit_hwtstamp_validate,
 };

-- 
2.43.0

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