Re: [PATCH] net: macb: Fix regression breaking non-MDIO fixed-link PHYs

Hello Ahmed, Uwe,

On Tue, Aug 14, 2018 at 05:58:12PM +0200, Uwe Kleine-König wrote:

Hello Ahmad,


On Tue, Aug 14, 2018 at 04:12:40PM +0200, Ahmad Fatoum wrote:

quoted

The referenced commit broke initializing macb on the EVB-KSZ9477 eval board.
There, of_mdiobus_register was called even for the fixed-link representing
the SPI-connected switch PHY, with the result that the driver attempts to
enumerate PHYs on a non-existent MDIO bus:

	libphy: MACB_mii_bus: probed
	mdio_bus f0028000.ethernet-ffffffff: fixed-link has invalid PHY address
	mdio_bus f0028000.ethernet-ffffffff: scan phy fixed-link at address 0
        [snip]
	mdio_bus f0028000.ethernet-ffffffff: scan phy fixed-link at address 31
	macb f0028000.ethernet: broken fixed-link specification

Cc: <redacted>
Fixes: 739de9a1563a ("net: macb: Reorganize macb_mii bringup")

I added the people involved in 739de9a1563a to Cc. Maybe they want to
comment. So not stripping the remaining part of the original mail.

Best regards
Uwe

You should probably prod Andrew Lunn, he suggested that I move the fixed
link code from macb_mii_init() to _probe(). Here, you're at least partially
directly undoing that.

(ref: https://www.mail-archive.com/netdev@vger.kernel.org/msg221018.html)

quoted

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/net/ethernet/cadence/macb_main.c | 26 +++++++++++++++---------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index a6c911bb5ce2..d202a03c42ed 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c

@@ -481,11 +481,6 @@ static int macb_mii_probe(struct net_device *dev)
 
 	if (np) {
 		if (of_phy_is_fixed_link(np)) {
-			if (of_phy_register_fixed_link(np) < 0) {
-				dev_err(&bp->pdev->dev,
-					"broken fixed-link specification\n");
-				return -ENODEV;
-			}
 			bp->phy_node = of_node_get(np);
 		} else {
 			bp->phy_node = of_parse_phandle(np, "phy-handle", 0);

@@ -568,7 +563,7 @@ static int macb_mii_init(struct macb *bp)
 {
 	struct macb_platform_data *pdata;
 	struct device_node *np;
-	int err;
+	int err = -ENXIO;
 
 	/* Enable management port */
 	macb_writel(bp, NCR, MACB_BIT(MPE));

@@ -591,10 +586,21 @@ static int macb_mii_init(struct macb *bp)
 	dev_set_drvdata(&bp->dev->dev, bp->mii_bus);
 
 	np = bp->pdev->dev.of_node;
-	if (pdata)
-		bp->mii_bus->phy_mask = pdata->phy_mask;
+	if (np && of_phy_is_fixed_link(np)) {
+		if (of_phy_register_fixed_link(np) < 0) {
+			dev_err(&bp->pdev->dev,
+					"broken fixed-link specification\n");
+			goto err_out_free_mdiobus;
+		}
+
+		err = mdiobus_register(bp->mii_bus);
+	} else {
+		if (pdata)
+			bp->mii_bus->phy_mask = pdata->phy_mask;
+
+		err = of_mdiobus_register(bp->mii_bus, np);
+	}
 
-	err = of_mdiobus_register(bp->mii_bus, np);
 	if (err)
 		goto err_out_free_mdiobus;
 

@@ -606,9 +612,9 @@ static int macb_mii_init(struct macb *bp)
 
 err_out_unregister_bus:
 	mdiobus_unregister(bp->mii_bus);
+err_out_free_mdiobus:
 	if (np && of_phy_is_fixed_link(np))
 		of_phy_deregister_fixed_link(np);
-err_out_free_mdiobus:
 	of_node_put(bp->phy_node);
 	mdiobus_free(bp->mii_bus);
 err_out:

-- 
2.18.0

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://urldefense.proofpoint.com/v2/url?u=http-3A__www.pengutronix.de_&d=DwIDAw&c=I_0YwoKy7z5LMTVdyO6YCiE2uzI1jjZZuIPelcSjixA&r=8iZb7YNOSMVIG_mTIHDL03ZcObgQI_gGlWrSewdGETA&m=IQAK1YsKs7Z2bvZxuajiSXw3asFiEztQKYkvy-LpBn8&s=XKrOhFxQshoEcDxMZVSATnJW2cbaD16mQofKdEbJVW0&e=  |

-- 
Brad Mouring
Senior Software Engineer
National Instruments
512-683-6610 / bmouring@ni.com