Re: [PATCH net 2/2] net: phylink: use USXGMII control-word format to parse Q-USGMII word

[Russell King (Oracle)]

On Thu, Jun 08, 2023 at 06:34:15PM +0200, Maxime Chevallier wrote:
> diff --git a/include/uapi/linux/mdio.h b/include/uapi/linux/mdio.h
> index 256b463e47a6..1d20a9082507 100644
> --- a/include/uapi/linux/mdio.h
> +++ b/include/uapi/linux/mdio.h
> @@ -444,4 +444,7 @@ static inline __u16 mdio_phy_id_c45(int prtad, int devad)
>  #define MDIO_USXGMII_5000FULL		0x1a00	/* 5000Mbps full-duplex */
>  #define MDIO_USXGMII_LINK		0x8000	/* PHY link with copper-side partner */
>  
> +/* Usgmii control word is based on Usxgmii, masking away 2.5, 5 and 10Gbps */
> +#define MDIO_USGMII_SPD_MASK		0x0600

This isn't correct:

11:9	Speed: Bit 11, 10, 9:
	1 1 1 to 011 = Reserved
	0 1 0 = 1000 Mbps: 1000BASE-TX, 1000BASE-X
	0 0 1 = 100 Mbps: 100BASE-TX, 100BASE-FX
	0 0 0 = 10 Mbps: 10BASET, 10BASE2, 10BASE5

If we only look at bits 10 and 9, then we're interpreting the reserved
combinations as valid as well.

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