Re: [net-next v2 02/12] net: dsa: add Renesas RZ/N1 switch tag driver

[Florian Fainelli <f.fainelli@gmail.com>]

On 4/29/22 07:34, Clément Léger wrote:
> The switch that is present on the Renesas RZ/N1 SoC uses a specific
> VLAN value followed by 6 bytes which contains forwarding configuration.
> 
> Signed-off-by: Clément Léger <clement.leger@bootlin.com>
> ---

[snip]

> +struct a5psw_tag {
> +	__be16 ctrl_tag;
> +	__be16 ctrl_data;
> +	__be16 ctrl_data2_hi;
> +	__be16 ctrl_data2_lo;
> +} __packed;

The structure should already be naturally aligned.

> +
> +static struct sk_buff *a5psw_tag_xmit(struct sk_buff *skb, struct net_device *dev)
> +{
> +	struct dsa_port *dp = dsa_slave_to_port(dev);
> +	struct a5psw_tag *ptag;
> +	u32 data2_val;
> +
> +	BUILD_BUG_ON(sizeof(*ptag) != A5PSW_TAG_LEN);
> +
> +	/* The Ethernet switch we are interfaced with needs packets to be at
> +	 * least 64 bytes (including FCS) otherwise they will be discarded when
> +	 * they enter the switch port logic. When tagging is enabled, we need
> +	 * to make sure that packets are at least 68 bytes (including FCS and
> +	 * tag).

Did you mean 70 bytes since your tag is 6, and not 4 bytes?
-- 
Florian