Re: [PATCH net-next v4 1/6] net: enetc: Add pseudo-MAC support for ENETCv4 Ports via a fixed-link node

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential
issue to consider:
- [Medium] net: enetc: enetc_phylink_match_pseudo_mac_speed() returns
  >10G fixed-link
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commit 15e36db0338302292004a6cbf3727d8f9d63565f
Author: Claudiu Manoil <claudiu.manoil@nxp.com>

net: enetc: Add pseudo-MAC support for ENETCv4 Ports via a fixed-link node

This commit adds pseudo-MAC support for ENETCv4 ports lacking static DT
nodes by synthesizing a fixed-link DT subnode at probe time with the speed
derived from PCR[PSPEED].

> diff --git a/drivers/net/ethernet/freescale/enetc/enetc_pf_common.c b/drivers/net/ethernet/freescale/enetc/enetc_pf_common.c
> index 8facc8bf8693a..b032b586f07b4 100644
> --- a/drivers/net/ethernet/freescale/enetc/enetc_pf_common.c
> +++ b/drivers/net/ethernet/freescale/enetc/enetc_pf_common.c
> @@ -436,6 +436,43 @@ void enetc_mdiobus_destroy(struct enetc_pf *pf)
>  }
>  EXPORT_SYMBOL_GPL(enetc_mdiobus_destroy);
>  
> +static struct {
> +	unsigned long mac_cap;
> +	int speed; /* descending order sorted  */
> +} enetc_phylink_pseudo_mac_caps[] = {
> +	{ MAC_25000FD,  SPEED_25000 },
> +	{ MAC_20000FD,  SPEED_20000 },
> +	{ MAC_10000FD,  SPEED_10000 },
> +	{ MAC_5000FD,   SPEED_5000  },
> +	{ MAC_2500FD,   SPEED_2500  },
> +	{ MAC_1000FD,   SPEED_1000  },
> +	{ MAC_100FD,    SPEED_100   },
> +	{ MAC_10FD,     SPEED_10    },
> +};
> +
> +static unsigned long enetc_phylink_get_pseudo_mac_caps(void)
> +{
> +	unsigned long mac_caps = 0;
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(enetc_phylink_pseudo_mac_caps); i++)
> +		mac_caps |= enetc_phylink_pseudo_mac_caps[i].mac_cap;
> +
> +	return mac_caps;
> +}
> +
> +int enetc_phylink_match_pseudo_mac_speed(int speed)
> +{
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(enetc_phylink_pseudo_mac_caps); i++)
> +		if (enetc_phylink_pseudo_mac_caps[i].speed <= speed)
> +			return enetc_phylink_pseudo_mac_caps[i].speed;
> +
> +	return SPEED_UNKNOWN;
> +}
> +EXPORT_SYMBOL_GPL(enetc_phylink_match_pseudo_mac_speed);

[Severity: Medium]
Can phylink_parse_fixedlink() handle SPEED_20000 or SPEED_25000 when
enetc4_add_ppm_fixed_link() writes the result of
enetc_phylink_match_pseudo_mac_speed() into the fixed-link DT node?

When PCR[PSPEED] is configured for 20 Gbps or 25 Gbps at boot,
enetc_phylink_match_pseudo_mac_speed() returns 20000 or 25000, but
phylink_fill_fixedlink_supported() only populates linkmodes up to
10000baseT_Full:

drivers/net/phy/phylink.c:phylink_fill_fixedlink_supported() {
    ...
	linkmode_set_bit(ETHTOOL_LINK_MODE_2500baseT_Full_BIT, supported);
	linkmode_set_bit(ETHTOOL_LINK_MODE_5000baseT_Full_BIT, supported);
	linkmode_set_bit(ETHTOOL_LINK_MODE_10000baseT_Full_BIT, supported);
}

As a result, phy_caps_lookup() in phylink_parse_fixedlink() returns NULL,
triggering a phylink warning ("fixed link full duplex 20000Mbps not
recognised") and leaving pl->supported, pl->link_config.advertising, and
pl->link_config.lp_advertising with no speed linkmode bits set.

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Sashiko AI review · https://sashiko.dev/#/patchset/cover.1794581338.git.claudiu.manoil@nxp.com?part=1