Re: [PATCH] net: mv643xx_eth: handle EPROBE_DEFER

[Mauri Sandberg]

Hello Andrew,

On 21.02.22 14:21, Andrew Lunn wrote:
> On Mon, Feb 21, 2022 at 08:24:41AM +0200, Mauri Sandberg wrote:
> > Obtaining MAC address may be deferred in cases when the MAC is stored
> > in NVMEM block and it may now be ready upon the first retrieval attempt
> > returing EPROBE_DEFER. Handle it here and leave logic otherwise as it
> > was.
> >
> > Signed-off-by: Mauri Sandberg <maukka@xxxxxxxxxxxx>
> > ---
> >   drivers/net/ethernet/marvell/mv643xx_eth.c | 5 ++++-
> >   1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/ethernet/marvell/mv643xx_eth.c b/drivers/net/ethernet/marvell/mv643xx_eth.c
> > index 105247582684..0694f53981f2 100644
> > --- a/drivers/net/ethernet/marvell/mv643xx_eth.c
> > +++ b/drivers/net/ethernet/marvell/mv643xx_eth.c
> > @@ -2740,7 +2740,10 @@ static int mv643xx_eth_shared_of_add_port(struct platform_device *pdev,
> >   		return -EINVAL;
> >   	}
> >   
> > -	of_get_mac_address(pnp, ppd.mac_addr);
> > +	ret = of_get_mac_address(pnp, ppd.mac_addr);
> > +
> > +	if (ret == -EPROBE_DEFER)
> > +		return ret;
> Hi Mauri
>
> There appears to be a follow on issue. There can be multiple ports. So
> it could be the first port does not use a MAC address from the NVMEM,
> but the second one does. The first time in
> mv643xx_eth_shared_of_add_port() is successful and a platform device
> is added. The second port can then fail with -EPROBE_DEFER. That
> causes the probe to fail, but the platform device will not be
> removed. The next time the driver is probed, it will add a second
> platform device for the first port, causing bad things to happen.
>
> Please can you add code to remove the platform device when the probe
> fails.

I am looking at the vector 'port_platdev' that holds pointers to already 
initialised ports. There is this mv643xx_eth_shared_of_remove(), which 
probably could be utilised to remove them. Should I remove the platform 
devices only in case of probe defer or always if probe fails?