Re: [RFC PATCH net-next v3 06/20] net: dsa: qca8k: handle error with qca8k_write operation

On Wed, May 05, 2021 at 02:41:24AM +0200, Andrew Lunn wrote:

quoted

-static void
+static int
 qca8k_write(struct qca8k_priv *priv, u32 reg, u32 val)
 {
+	struct mii_bus *bus = priv->bus;
 	u16 r1, r2, page;
 	int ret;
 
 	qca8k_split_addr(reg, &r1, &r2, &page);
 
-	mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED);
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
 
 	ret = qca8k_set_page(priv->bus, page);
 	if (ret < 0)

@@ -183,6 +184,7 @@ qca8k_write(struct qca8k_priv *priv, u32 reg, u32 val)
 
 exit:
 	mutex_unlock(&priv->bus->mdio_lock);
+	return ret;
 }

Same comment as read. Maybe put this and the other similar change into one patch.

quoted

@@ -636,7 +660,9 @@ qca8k_mdio_read(struct qca8k_priv *priv, int port, u32 regnum)
 	      QCA8K_MDIO_MASTER_READ | QCA8K_MDIO_MASTER_PHY_ADDR(phy) |
 	      QCA8K_MDIO_MASTER_REG_ADDR(regnum);
 
-	qca8k_write(priv, QCA8K_MDIO_MASTER_CTRL, val);
+	ret = qca8k_write(priv, QCA8K_MDIO_MASTER_CTRL, val);
+	if (ret)
+		return ret;
 
 	if (qca8k_busy_wait(priv, QCA8K_MDIO_MASTER_CTRL,
 			    QCA8K_MDIO_MASTER_BUSY))

@@ -767,12 +793,18 @@ qca8k_setup(struct dsa_switch *ds)
 		      QCA8K_GLOBAL_FW_CTRL0_CPU_PORT_EN);
 
 	/* Enable MIB counters */
-	qca8k_mib_init(priv);
+	ret = qca8k_mib_init(priv);
+	if (ret)
+		pr_warn("mib init failed");

Please use dev_warn().

quoted

 
 	/* Enable QCA header mode on the cpu port */
-	qca8k_write(priv, QCA8K_REG_PORT_HDR_CTRL(QCA8K_CPU_PORT),
-		    QCA8K_PORT_HDR_CTRL_ALL << QCA8K_PORT_HDR_CTRL_TX_S |
-		    QCA8K_PORT_HDR_CTRL_ALL << QCA8K_PORT_HDR_CTRL_RX_S);
+	ret = qca8k_write(priv, QCA8K_REG_PORT_HDR_CTRL(QCA8K_CPU_PORT),
+			  QCA8K_PORT_HDR_CTRL_ALL << QCA8K_PORT_HDR_CTRL_TX_S |
+			  QCA8K_PORT_HDR_CTRL_ALL << QCA8K_PORT_HDR_CTRL_RX_S);
+	if (ret) {
+		pr_err("failed enabling QCA header mode");

dev_err()

In general, always use dev_err(), dev_warn(), dev_info() etc, so we
know which device returned an error.

I notice that in the driver we use pr function so I assumed this was the
correct way to report errors with a dsa driver. Will change that.

     Andrew