On Mon, Nov 02, 2020 at 03:58:21PM +0800, DENG Qingfang wrote:
> MT7530/7531 has a global RX packet length register, which can be used
> to set MTU.
>
> Supported packet length values are 1522 (1518 if untagged), 1536, 1552,
> and multiple of 1024 (from 2048 to 15360).
>
> Signed-off-by: DENG Qingfang <dqf...@gmail.com>
> ---
> v1 -> v2:
> Avoid duplication of mt7530_rmw()
> Fix code wrapping
> ---
> drivers/net/dsa/mt7530.c | 49 ++++++++++++++++++++++++++++++++++++++++
> drivers/net/dsa/mt7530.h | 12 ++++++++++
> 2 files changed, 61 insertions(+)
>
> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> index de7692b763d8..ca39f81de75a 100644
> --- a/drivers/net/dsa/mt7530.c
> +++ b/drivers/net/dsa/mt7530.c
> @@ -1021,6 +1021,53 @@ mt7530_port_disable(struct dsa_switch *ds, int port)
> mutex_unlock(&priv->reg_mutex);
> }
>
> +static int
> +mt7530_port_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
> +{
> + struct mt7530_priv *priv = ds->priv;
> + struct mii_bus *bus = priv->bus;
> + int length;
> + u32 val;
> +
> + /* When a new MTU is set, DSA always set the CPU port's MTU to the
> + * largest MTU of the slave ports. Because the switch only has a global
> + * RX length register, only allowing CPU port here is enough.
> + */
> + if (!dsa_is_cpu_port(ds, port))
> + return 0;
> +
> + mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
> +
> + val = mt7530_mii_read(priv, MT7530_GMACCR);
> + val &= ~MAX_RX_PKT_LEN_MASK;
> +
> + /* RX length also includes Ethernet header, MTK tag, and FCS length */
> + length = new_mtu + ETH_HLEN + MTK_HDR_LEN + ETH_FCS_LEN;
> + if (length <= 1522)
> + val |= MAX_RX_PKT_LEN_1522;
Could you please fix the checkpatch warnings here?
> + else if (length <= 1536)
> + val |= MAX_RX_PKT_LEN_1536;
> + else if (length <= 1552)
> + val |= MAX_RX_PKT_LEN_1552;
> + else {
> + val &= ~MAX_RX_JUMBO_MASK;
> + val |= MAX_RX_JUMBO(DIV_ROUND_UP(length, 1024));
> + val |= MAX_RX_PKT_LEN_JUMBO;
> + }
> +
> + mt7530_mii_write(priv, MT7530_GMACCR, val);
> +
> + mutex_unlock(&bus->mdio_lock);
> +
> + return 0;
> +}
> +
