net: usb: lan78xx: Improve error handling in dataport and multicast writes

Update `lan78xx_dataport_write` and `lan78xx_deferred_multicast_write`
to:
- Handle errors during register read/write operations.
- Exit immediately on errors and log them using `%pe` for clarity.
- Avoid silent failures by propagating error codes properly.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20241204084142.1152696-11-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 2ae9565b5044fcef192cd44c8080dc7d9e4d6da6..d5f6367d37148b0e9597f521a4d927d727902d40 100644 (file)
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -1371,7 +1371,7 @@ static int lan78xx_dataport_wait_not_busy(struct lan78xx_net *dev)
 
                ret = lan78xx_read_reg(dev, DP_SEL, &dp_sel);
                if (unlikely(ret < 0))
-                       return -EIO;
+                       return ret;
 
                if (dp_sel & DP_SEL_DPRDY_)
                        return 0;
@@ -1381,44 +1381,51 @@ static int lan78xx_dataport_wait_not_busy(struct lan78xx_net *dev)
 
        netdev_warn(dev->net, "%s timed out", __func__);
 
-       return -EIO;
+       return -ETIMEDOUT;
 }
 
 static int lan78xx_dataport_write(struct lan78xx_net *dev, u32 ram_select,
                                  u32 addr, u32 length, u32 *buf)
 {
        struct lan78xx_priv *pdata = (struct lan78xx_priv *)(dev->data[0]);
-       u32 dp_sel;
        int i, ret;
 
-       if (usb_autopm_get_interface(dev->intf) < 0)
-               return 0;
+       ret = usb_autopm_get_interface(dev->intf);
+       if (ret < 0)
+               return ret;
 
        mutex_lock(&pdata->dataport_mutex);
 
        ret = lan78xx_dataport_wait_not_busy(dev);
        if (ret < 0)
-               goto done;
+               goto dataport_write;
 
-       ret = lan78xx_read_reg(dev, DP_SEL, &dp_sel);
-
-       dp_sel &= ~DP_SEL_RSEL_MASK_;
-       dp_sel |= ram_select;
-       ret = lan78xx_write_reg(dev, DP_SEL, dp_sel);
+       ret = lan78xx_update_reg(dev, DP_SEL, DP_SEL_RSEL_MASK_, ram_select);
+       if (ret < 0)
+               goto dataport_write;
 
        for (i = 0; i < length; i++) {
                ret = lan78xx_write_reg(dev, DP_ADDR, addr + i);
+               if (ret < 0)
+                       goto dataport_write;
 
                ret = lan78xx_write_reg(dev, DP_DATA, buf[i]);
+               if (ret < 0)
+                       goto dataport_write;
 
                ret = lan78xx_write_reg(dev, DP_CMD, DP_CMD_WRITE_);
+               if (ret < 0)
+                       goto dataport_write;
 
                ret = lan78xx_dataport_wait_not_busy(dev);
                if (ret < 0)
-                       goto done;
+                       goto dataport_write;
        }
 
-done:
+dataport_write:
+       if (ret < 0)
+               netdev_warn(dev->net, "dataport write failed %pe", ERR_PTR(ret));
+
        mutex_unlock(&pdata->dataport_mutex);
        usb_autopm_put_interface(dev->intf);
 
@@ -1454,23 +1461,39 @@ static void lan78xx_deferred_multicast_write(struct work_struct *param)
        struct lan78xx_priv *pdata =
                        container_of(param, struct lan78xx_priv, set_multicast);
        struct lan78xx_net *dev = pdata->dev;
-       int i;
+       int i, ret;
 
        netif_dbg(dev, drv, dev->net, "deferred multicast write 0x%08x\n",
                  pdata->rfe_ctl);
 
-       lan78xx_dataport_write(dev, DP_SEL_RSEL_VLAN_DA_, DP_SEL_VHF_VLAN_LEN,
-                              DP_SEL_VHF_HASH_LEN, pdata->mchash_table);
+       ret = lan78xx_dataport_write(dev, DP_SEL_RSEL_VLAN_DA_,
+                                    DP_SEL_VHF_VLAN_LEN,
+                                    DP_SEL_VHF_HASH_LEN, pdata->mchash_table);
+       if (ret < 0)
+               goto multicast_write_done;
 
        for (i = 1; i < NUM_OF_MAF; i++) {
-               lan78xx_write_reg(dev, MAF_HI(i), 0);
-               lan78xx_write_reg(dev, MAF_LO(i),
-                                 pdata->pfilter_table[i][1]);
-               lan78xx_write_reg(dev, MAF_HI(i),
-                                 pdata->pfilter_table[i][0]);
+               ret = lan78xx_write_reg(dev, MAF_HI(i), 0);
+               if (ret < 0)
+                       goto multicast_write_done;
+
+               ret = lan78xx_write_reg(dev, MAF_LO(i),
+                                       pdata->pfilter_table[i][1]);
+               if (ret < 0)
+                       goto multicast_write_done;
+
+               ret = lan78xx_write_reg(dev, MAF_HI(i),
+                                       pdata->pfilter_table[i][0]);
+               if (ret < 0)
+                       goto multicast_write_done;
        }
 
-       lan78xx_write_reg(dev, RFE_CTL, pdata->rfe_ctl);
+       ret = lan78xx_write_reg(dev, RFE_CTL, pdata->rfe_ctl);
+
+multicast_write_done:
+       if (ret < 0)
+               netdev_warn(dev->net, "multicast write failed %pe", ERR_PTR(ret));
+       return;
 }
 
 static void lan78xx_set_multicast(struct net_device *netdev)