Re: [PATCH net-next 07/15] net: dsa: mt7530: do not run mt7530_setup_port5() if port 5 is disabled

[Arınç ÜNAL]

Hi Simon.

On 21.11.2023 21:53, Simon Horman wrote:
> On Sat, Nov 18, 2023 at 03:31:57PM +0300, Arınç ÜNAL wrote:
> > There's no need to run all the code on mt7530_setup_port5() if port 5 is
> > disabled. The only case for calling mt7530_setup_port5() from
> > mt7530_setup() is when PHY muxing is enabled. That is because port 5 is not
> > defined as a port on the devicetree, therefore, it cannot be controlled by
> > phylink.
> >
> > Because of this, run mt7530_setup_port5() if priv->p5_intf_sel is
> > P5_INTF_SEL_PHY_P0 or P5_INTF_SEL_PHY_P4. Remove the P5_DISABLED case from
> > mt7530_setup_port5().
> >
> > Stop initialising the interface variable as the remaining cases will always
> > call mt7530_setup_port5() with it initialised.
> >
> > Signed-off-by: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>
> > Reviewed-by: Vladimir Oltean <olteanv@xxxxxxxxx>
> > ---
> >   drivers/net/dsa/mt7530.c | 9 +++------
> >   1 file changed, 3 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> > index fc87ec817672..1aab4c3f28b0 100644
> > --- a/drivers/net/dsa/mt7530.c
> > +++ b/drivers/net/dsa/mt7530.c
> > @@ -942,9 +942,6 @@ static void mt7530_setup_port5(struct dsa_switch *ds, phy_interface_t interface)
> >   		/* MT7530_P5_MODE_GMAC: P5 -> External phy or 2nd GMAC */
> >   		val &= ~MHWTRAP_P5_DIS;
> >   		break;
> > -	case P5_DISABLED:
> > -		interface = PHY_INTERFACE_MODE_NA;
> > -		break;
> >   	default:
> >   		dev_err(ds->dev, "Unsupported p5_intf_sel %d\n",
> >   			priv->p5_intf_sel);
> > @@ -2313,8 +2310,6 @@ mt7530_setup(struct dsa_switch *ds)
> >   		 * Set priv->p5_intf_sel to the appropriate value if PHY muxing
> >   		 * is detected.
> >   		 */
> > -		interface = PHY_INTERFACE_MODE_NA;
> > -
> >   		for_each_child_of_node(dn, mac_np) {
> >   			if (!of_device_is_compatible(mac_np,
> >   						     "mediatek,eth-mac"))
> > @@ -2346,7 +2341,9 @@ mt7530_setup(struct dsa_switch *ds)
> >   			break;
> >   		}
> >   
> > -		mt7530_setup_port5(ds, interface);
> > +		if (priv->p5_intf_sel == P5_INTF_SEL_PHY_P0 ||
> > +		    priv->p5_intf_sel == P5_INTF_SEL_PHY_P4)
> > +			mt7530_setup_port5(ds, interface);
>
> Hi Arınç,
>
> It appears that interface is now uninitialised here.
>
> Flagged by Smatch.

I'm not sure why it doesn't catch that for mt7530_setup_port5() to run
here, priv->p5_intf_sel must be either P5_INTF_SEL_PHY_P0 or
P5_INTF_SEL_PHY_P4. And for that to happen, the interface variable will be
initialised.

for_each_child_of_node(dn, mac_np) {
	if (!of_device_is_compatible(mac_np,
				     "mediatek,eth-mac"))
		continue;

	ret = of_property_read_u32(mac_np, "reg", &id);
	if (ret < 0 || id != 1)
		continue;

	phy_node = of_parse_phandle(mac_np, "phy-handle", 0);
	if (!phy_node)
		continue;

	if (phy_node->parent == priv->dev->of_node->parent) {
		ret = of_get_phy_mode(mac_np, &interface);
		if (ret && ret != -ENODEV) {
			of_node_put(mac_np);
			of_node_put(phy_node);
			return ret;
		}
		id = of_mdio_parse_addr(ds->dev, phy_node);
		if (id == 0)
			priv->p5_intf_sel = P5_INTF_SEL_PHY_P0;
		if (id == 4)
			priv->p5_intf_sel = P5_INTF_SEL_PHY_P4;
	}
	of_node_put(mac_np);
	of_node_put(phy_node);
	break;
}

if (priv->p5_intf_sel == P5_INTF_SEL_PHY_P0 ||
    priv->p5_intf_sel == P5_INTF_SEL_PHY_P4)
	mt7530_setup_port5(ds, interface);

Arınç