[PATCH net] ixgbe: fix probing of multi-port devices with one MDIO

[PATCH net] ixgbe: fix probing of multi-port devices with one MDIO

[Jakub Kicinski]

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>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c | 23 ++++++++++++--------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c
index f77fa3e4fdd1..fc389eecdd2b 100644
--- 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(struct ixgbe_hw *hw)
  **/
 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 *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));
-- 
2.26.2

Re: [PATCH net] ixgbe: fix probing of multi-port devices with one MDIO

[Ian Kumlien]

On Sat, Oct 17, 2020 at 1:20 AM Jakub Kicinski <kuba@kernel.org> wrote:
>
> 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.

Nice, that fixes it!

You can add a:
Tested-by: Ian Kumlien <ian.kumlien@gmail.com>

;)

> Fixes: 09ef193fef7e ("net: ethernet: ixgbe: check the return value of ixgbe_mii_bus_init()")
> Reported-by: Ian Kumlien <ian.kumlien@gmail.com>
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c | 23 ++++++++++++--------
>  1 file changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c
> index f77fa3e4fdd1..fc389eecdd2b 100644
> --- 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(struct ixgbe_hw *hw)
>   **/
>  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 *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));
> --
> 2.26.2
>

Re: [PATCH net] ixgbe: fix probing of multi-port devices with one MDIO

[Jakub Kicinski]

On Sat, 17 Oct 2020 01:50:59 +0200 Ian Kumlien wrote:
> On Sat, Oct 17, 2020 at 1:20 AM Jakub Kicinski <kuba@kernel.org> wrote:
> > 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.  
> 
> Nice, that fixes it!
> 
> You can add a:
> Tested-by: Ian Kumlien <ian.kumlien@gmail.com>

Will do, thanks!

Tony, should I apply directly to net?

Re: [PATCH net] ixgbe: fix probing of multi-port devices with one MDIO

[Jesse Brandeburg]

Jakub Kicinski wrote:

> On Sat, 17 Oct 2020 01:50:59 +0200 Ian Kumlien wrote:
> > On Sat, Oct 17, 2020 at 1:20 AM Jakub Kicinski <kuba@kernel.org> wrote:
> > > 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.  
> > 
> > Nice, that fixes it!
> > 
> > You can add a:
> > Tested-by: Ian Kumlien <ian.kumlien@gmail.com>
> 
> Will do, thanks!
> 
> Tony, should I apply directly to net?

Thank you Kuba!

Seems like a pretty straight forward bug-fix. I recommend
you apply it directly.

Acked-by: Jesse Brandeburg <jesse.brandeburg@intel.com>

Re: [PATCH net] ixgbe: fix probing of multi-port devices with one MDIO

[Jakub Kicinski]

On Fri, 16 Oct 2020 17:48:07 -0700 Jesse Brandeburg wrote:
> Jakub Kicinski wrote:
> 
> > On Sat, 17 Oct 2020 01:50:59 +0200 Ian Kumlien wrote:  
> > > On Sat, Oct 17, 2020 at 1:20 AM Jakub Kicinski <kuba@kernel.org> wrote:  
> > > > 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.    
> > > 
> > > Nice, that fixes it!
> > > 
> > > You can add a:
> > > Tested-by: Ian Kumlien <ian.kumlien@gmail.com>  
> > 
> > Will do, thanks!
> > 
> > Tony, should I apply directly to net?  
> 
> Thank you Kuba!
> 
> Seems like a pretty straight forward bug-fix. I recommend
> you apply it directly.

Done.

> Acked-by: Jesse Brandeburg <jesse.brandeburg@intel.com>

Thank you!