Re: [PATCH net-next v7 08/10] net: dsa: realtek: rtl8365mb: re-latch the family D SerDes

[Alvin Šipraga]

On Mon, Nov 02, 2026 at 03:43:45PM +0100, Mieczyslaw Nalewaj wrote:
> The family D receiver latches on the DISABLE -> HSGMII edge in SDS_MISC
> rather than on the value, and it will not latch until the MAC at the
> other end of the trunk has brought its own half of the link up. If it
> does not latch, the trunk reports 2.5Gbps/Full on both sides but moves
> no frames: the CPU MAC transmits, the switch CPU port counts no octets,
> and there are no CRC, alignment or FIFO errors.

[...]

>  
>  #define pcs_to_rtl8365mb(_pcs) container_of((_pcs), struct rtl8365mb, pcs)
> @@ -1357,43 +1404,53 @@ static int rtl8365mb_ext_config_rgmii(struct realtek_priv *priv, int port,
>  static int rtl8365mb_sds_write(struct realtek_priv *priv, u8 index,
>  			       u16 addr, u16 data)
>  {
> +	struct rtl8365mb *mb = priv->chip_data;
>  	int ret;
>  
> +	mutex_lock(&mb->sds_lock);

OK, I don't think I can give a particularly good review of this patch
since I didn't follow the previous work for SerDes support... But at
least, can you use guard(mutex)() here? ;-) And elsewhere it might
apply.

> +
>  	ret = regmap_write(priv->map, RTL8365MB_SDS_INDACS_DATA_REG, data);
>  	if (ret)
> -		return ret;
> +		goto out_unlock;
>  
>  	ret = regmap_write(priv->map, RTL8365MB_SDS_INDACS_ADR_REG, addr);
>  	if (ret)
> -		return ret;
> +		goto out_unlock;
>  
>  	/* The SerDes indirect access engine completes the command within the
>  	 * register write transaction, so there is no need to wait or poll for
>  	 * completion before the next access, matching the vendor driver.
>  	 */
> -	return regmap_write(priv->map, RTL8365MB_SDS_INDACS_CMD_REG,
> -			    RTL8365MB_SDS_INDACS_CMD_RUN_MASK |
> -			    RTL8365MB_SDS_INDACS_CMD_WR_MASK |
> -			    FIELD_PREP(RTL8365MB_SDS_INDACS_CMD_INDEX_MASK,
> -				       index));
> +	ret = regmap_write(priv->map, RTL8365MB_SDS_INDACS_CMD_REG,
> +			   RTL8365MB_SDS_INDACS_CMD_RUN_MASK |
> +			   RTL8365MB_SDS_INDACS_CMD_WR_MASK |
> +			   FIELD_PREP(RTL8365MB_SDS_INDACS_CMD_INDEX_MASK,
> +				      index));
> +
> +out_unlock:
> +	mutex_unlock(&mb->sds_lock);
> +	return ret;
>  }
>  
>  static int rtl8365mb_sds_read(struct realtek_priv *priv, u8 index,
>  			      u16 addr, u16 *data)
>  {
> +	struct rtl8365mb *mb = priv->chip_data;
>  	u32 val;
>  	int ret;
>  
> +	mutex_lock(&mb->sds_lock);

Like here, etc.

Kind regards,
Alvin