[PATCH 5.9 055/757] ixgbe: fix probing of multi-port devices with one MDIO

Greg Kroah-Hartman
2020-10-27T15:33:13Z

From: Jakub Kicinski <kuba@kernel.org>

[ Upstream commit bd7f14df9492e7d3772812a215fca66e6737e598 ]

Ian reports that after upgrade from v5.8.14 to v5.9 only one
of his 4 ixgbe netdevs appear in the system.

Quoting the comment on ixgbe_x550em_a_has_mii():
* Returns true if hw points to lowest numbered PCI B:D.F x550_em_a device in
* the SoC. There are up to 4 MACs sharing a single MDIO bus on the x550em_a,
* but we only want to register one MDIO bus.

This matches the symptoms, since the return value from
ixgbe_mii_bus_init() is no longer ignored we need to handle
the higher ports of x550em without an error.

Fixes: 09ef193fef7e ("net: ethernet: ixgbe: check the return value of ixgbe_mii_bus_init()")
Reported-by: Ian Kumlien <ian.kumlien@gmail.com>
Tested-by: Ian Kumlien <ian.kumlien@gmail.com>
Acked-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Link: https://lore.kernel.org/r/20201016232006.3352947-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)

--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c
@@ -901,15 +901,13 @@ static bool ixgbe_x550em_a_has_mii(struc
**/
s32 ixgbe_mii_bus_init(struct ixgbe_hw *hw)
{
+ s32 (*write)(struct mii_bus *bus, int addr, int regnum, u16 val);
+ s32 (*read)(struct mii_bus *bus, int addr, int regnum);
struct ixgbe_adapter *adapter = hw->back;
struct pci_dev *pdev = adapter->pdev;
struct device *dev = &adapter->netdev->dev;
struct mii_bus *bus;

- bus = devm_mdiobus_alloc(dev);
- if (!bus)
- return -ENOMEM;
-
switch (hw->device_id) {
/* C3000 SoCs */
case IXGBE_DEV_ID_X550EM_A_KR:
@@ -922,16 +920,23 @@ s32 ixgbe_mii_bus_init(struct ixgbe_hw *
case IXGBE_DEV_ID_X550EM_A_1G_T:
case IXGBE_DEV_ID_X550EM_A_1G_T_L:
if (!ixgbe_x550em_a_has_mii(hw))
- return -ENODEV;
- bus->read = &ixgbe_x550em_a_mii_bus_read;
- bus->write = &ixgbe_x550em_a_mii_bus_write;
+ return 0;
+ read = &ixgbe_x550em_a_mii_bus_read;
+ write = &ixgbe_x550em_a_mii_bus_write;
break;
default:
- bus->read = &ixgbe_mii_bus_read;
- bus->write = &ixgbe_mii_bus_write;
+ read = &ixgbe_mii_bus_read;
+ write = &ixgbe_mii_bus_write;
break;
}

+ bus = devm_mdiobus_alloc(dev);
+ if (!bus)
+ return -ENOMEM;
+
+ bus->read = read;
+ bus->write = write;
+
/* Use the position of the device in the PCI hierarchy as the id */
snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mdio-%s", ixgbe_driver_name,
pci_name(pdev));