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From: Saravana Kannan <saravanak@google.com>
To: Andrew Lunn <andrew@lunn.ch>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>,
	Marc Zyngier <maz@kernel.org>,
	Neil Armstrong <narmstrong@baylibre.com>,
	Kevin Hilman <khilman@baylibre.com>,
	kernel-team@android.com, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v1 3/3] net: mdio-mux: Handle -EPROBE_DEFER correctly
Date: Wed,  4 Aug 2021 14:43:32 -0700	[thread overview]
Message-ID: <20210804214333.927985-4-saravanak@google.com> (raw)
In-Reply-To: <20210804214333.927985-1-saravanak@google.com>

When registering mdiobus children, if we get an -EPROBE_DEFER, we shouldn't
ignore it and continue registering the rest of the mdiobus children. This
would permanently prevent the deferring child mdiobus from working instead
of reattempting it in the future. So, if a child mdiobus needs to be
reattempted in the future, defer the entire mdio-mux initialization.

This fixes the issue where PHYs sitting under the mdio-mux aren't
initialized correctly if the PHY's interrupt controller is not yet ready
when the mdio-mux is being probed. Additional context in the link below.

Link: https://lore.kernel.org/lkml/CAGETcx95kHrv8wA-O+-JtfH7H9biJEGJtijuPVN0V5dUKUAB3A@mail.gmail.com/#t
Signed-off-by: Saravana Kannan <saravanak@google.com>
---
 drivers/net/mdio/mdio-mux.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/mdio/mdio-mux.c b/drivers/net/mdio/mdio-mux.c
index 13035e2685c4..ebd001f0eece 100644
--- a/drivers/net/mdio/mdio-mux.c
+++ b/drivers/net/mdio/mdio-mux.c
@@ -175,11 +175,15 @@ int mdio_mux_init(struct device *dev,
 		cb->mii_bus->write = mdio_mux_write;
 		r = of_mdiobus_register(cb->mii_bus, child_bus_node);
 		if (r) {
+			mdiobus_free(cb->mii_bus);
+			if (r == -EPROBE_DEFER) {
+				ret_val = r;
+				goto err_loop;
+			}
+			devm_kfree(dev, cb);
 			dev_err(dev,
 				"Error: Failed to register MDIO bus for child %pOF\n",
 				child_bus_node);
-			mdiobus_free(cb->mii_bus);
-			devm_kfree(dev, cb);
 		} else {
 			cb->next = pb->children;
 			pb->children = cb;
-- 
2.32.0.554.ge1b32706d8-goog


  parent reply	other threads:[~2021-08-04 21:43 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-04 21:43 [PATCH v1 0/3] Clean up and fix error handling in mdio_mux_init() Saravana Kannan
2021-08-04 21:43 ` [PATCH v1 1/3] net: mdio-mux: Delete unnecessary devm_kfree Saravana Kannan
2021-08-07 14:23   ` Andrew Lunn
2021-08-04 21:43 ` [PATCH v1 2/3] net: mdio-mux: Don't ignore memory allocation errors Saravana Kannan
2021-08-07 15:46   ` Andrew Lunn
2021-08-04 21:43 ` Saravana Kannan [this message]
2021-08-07 15:49   ` [PATCH v1 3/3] net: mdio-mux: Handle -EPROBE_DEFER correctly Andrew Lunn
2021-08-05  9:02 ` [PATCH v1 0/3] Clean up and fix error handling in mdio_mux_init() Marc Zyngier
2021-08-05 18:36   ` Kevin Hilman
2021-08-05 18:37     ` Kevin Hilman
2021-08-05 18:47       ` Saravana Kannan
2021-08-05 10:31 ` David Miller

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