[PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral

Geert Uytterhoeven
2017-05-18T12:59:16Z

If an Ethernet PHY is initialized before the interrupt controller it is
connected to, a message like the following is printed:

irq: no irq domain found for /interrupt-controller@e61c0000 !

However, the actual error is ignored, leading to a non-functional (-1)
PHY interrupt later:

Micrel KSZ8041RNLI ee700000.ethernet-ffffffff:01: attached PHY driver [Micrel KSZ8041RNLI] (mii_bus:phy_addr=ee700000.ethernet-ffffffff:01, irq=-1)

Depending on whether the PHY driver will fall back to polling, Ethernet
may or may not work.

To fix this:
1. Switch of_mdiobus_register_phy() from irq_of_parse_and_map() to
of_irq_get().
Unlike the former, the latter returns -EPROBE_DEFER if the
interrupt controller is not yet available, so this condition can be
detected.
Other errors are handled the same as before, i.e. use the passed
mdio->irq[addr] as interrupt.
2. Propagate and handle errors from of_mdiobus_register_phy() and
of_mdiobus_register_device().

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
Seen on r8a7791/koelsch when using the new CPG/MSSR clock driver.
I assume it always happened on RZ/G1 in mainline.
---
drivers/of/of_mdio.c | 39 +++++++++++++++++++++++++++------------
1 file changed, 27 insertions(+), 12 deletions(-)

diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
index 7e4c80f9b6cda0d3..f9ac2893f56184be 100644
--- a/drivers/of/of_mdio.c
+++ b/drivers/of/of_mdio.c
@@ -44,7 +44,7 @@ static int of_get_phy_id(struct device_node *device, u32 *phy_id)
return -EINVAL;
}

-static void of_mdiobus_register_phy(struct mii_bus *mdio,
+static int of_mdiobus_register_phy(struct mii_bus *mdio,
struct device_node *child, u32 addr)
{
struct phy_device *phy;
@@ -60,9 +60,13 @@ static void of_mdiobus_register_phy(struct mii_bus *mdio,
else
phy = get_phy_device(mdio, addr, is_c45);
if (IS_ERR(phy))
- return;
+ return PTR_ERR(phy);

- rc = irq_of_parse_and_map(child, 0);
+ rc = of_irq_get(child, 0);
+ if (rc == -EPROBE_DEFER) {
+ phy_device_free(phy);
+ return rc;
+ }
if (rc > 0) {
phy->irq = rc;
mdio->irq[addr] = rc;
@@ -84,22 +88,23 @@ static void of_mdiobus_register_phy(struct mii_bus *mdio,
if (rc) {
phy_device_free(phy);
of_node_put(child);
- return;
+ return rc;
}

dev_dbg(&mdio->dev, "registered phy %s at address %i\n",
child->name, addr);
+ return 0;
}

-static void of_mdiobus_register_device(struct mii_bus *mdio,
- struct device_node *child, u32 addr)
+static int of_mdiobus_register_device(struct mii_bus *mdio,
+ struct device_node *child, u32 addr)
{
struct mdio_device *mdiodev;
int rc;

mdiodev = mdio_device_create(mdio, addr);
if (IS_ERR(mdiodev))
- return;
+ return PTR_ERR(mdiodev);

/* Associate the OF node with the device structure so it
* can be looked up later.
@@ -112,11 +117,12 @@ static void of_mdiobus_register_device(struct mii_bus *mdio,
if (rc) {
mdio_device_free(mdiodev);
of_node_put(child);
- return;
+ return rc;
}

dev_dbg(&mdio->dev, "registered mdio device %s at address %i\n",
child->name, addr);
+ return 0;
}

int of_mdio_parse_addr(struct device *dev, const struct device_node *np)
@@ -242,9 +248,11 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
}

if (of_mdiobus_child_is_phy(child))
- of_mdiobus_register_phy(mdio, child, addr);
+ rc = of_mdiobus_register_phy(mdio, child, addr);
else
- of_mdiobus_register_device(mdio, child, addr);
+ rc = of_mdiobus_register_device(mdio, child, addr);
+ if (rc)
+ goto unregister;
}

if (!scanphys)
@@ -265,12 +273,19 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
dev_info(&mdio->dev, "scan phy %s at address %i\n",
child->name, addr);

- if (of_mdiobus_child_is_phy(child))
- of_mdiobus_register_phy(mdio, child, addr);
+ if (of_mdiobus_child_is_phy(child)) {
+ rc = of_mdiobus_register_phy(mdio, child, addr);
+ if (rc)
+ goto unregister;
+ }
}
}

return 0;
+
+unregister:
+ mdiobus_unregister(mdio);
+ return rc;
}
EXPORT_SYMBOL(of_mdiobus_register);

--
2.7.4