Re: [PATCH net-next 1/5 v2] net: dsa: rtl8366rb: support bridge offloading

[Vladimir Oltean <olteanv@gmail.com>]

On Mon, Aug 30, 2021 at 11:48:55PM +0200, Linus Walleij wrote:
> From: DENG Qingfang <dqfext@gmail.com>
> 
> Use port isolation registers to configure bridge offloading.
> 
> Tested on the D-Link DIR-685, switching between ports and
> sniffing ports to make sure no packets leak.
> 
> Cc: Vladimir Oltean <olteanv@gmail.com>
> Cc: Alvin Šipraga <alsi@bang-olufsen.dk>
> Cc: Mauri Sandberg <sandberg@mailfence.com>
> Signed-off-by: DENG Qingfang <dqfext@gmail.com>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> ChangeLog v1->v2:
> - introduce RTL8366RB_PORT_ISO_PORTS() to shift the port
>   mask into place so we are not confused by the enable
>   bit.
> - Use this with dsa_user_ports() to isolate the CPU port
>   from itself.
> ---
>  drivers/net/dsa/rtl8366rb.c | 87 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 87 insertions(+)
> 
> diff --git a/drivers/net/dsa/rtl8366rb.c b/drivers/net/dsa/rtl8366rb.c
> index a89093bc6c6a..50ee7cd62484 100644
> --- a/drivers/net/dsa/rtl8366rb.c
> +++ b/drivers/net/dsa/rtl8366rb.c
> @@ -300,6 +300,13 @@
>  #define RTL8366RB_INTERRUPT_STATUS_REG	0x0442
>  #define RTL8366RB_NUM_INTERRUPT		14 /* 0..13 */
>  
> +/* Port isolation registers */
> +#define RTL8366RB_PORT_ISO_BASE		0x0F08
> +#define RTL8366RB_PORT_ISO(pnum)	(RTL8366RB_PORT_ISO_BASE + (pnum))
> +#define RTL8366RB_PORT_ISO_EN		BIT(0)
> +#define RTL8366RB_PORT_ISO_PORTS_MASK	GENMASK(7, 1)
> +#define RTL8366RB_PORT_ISO_PORTS(pmask)	(pmask << 1)

Would be nice to enclose pmask between a set of parentheses.

> +
>  /* bits 0..5 enable force when cleared */
>  #define RTL8366RB_MAC_FORCE_CTRL_REG	0x0F11
>  
> @@ -835,6 +842,22 @@ static int rtl8366rb_setup(struct dsa_switch *ds)
>  	if (ret)
>  		return ret;
>  
> +	/* Isolate all user ports so only the CPU port can access them */
> +	for (i = 0; i < RTL8366RB_PORT_NUM_CPU; i++) {
> +		ret = regmap_write(smi->map, RTL8366RB_PORT_ISO(i),
> +				   RTL8366RB_PORT_ISO_EN |
> +				   RTL8366RB_PORT_ISO_PORTS(BIT(RTL8366RB_PORT_NUM_CPU)));
> +		if (ret)
> +			return ret;
> +	}
> +	/* CPU port can access all ports */
> +	dev_info(smi->dev, "DSA user port mask: %08x\n", dsa_user_ports(ds));
> +	ret = regmap_write(smi->map, RTL8366RB_PORT_ISO(RTL8366RB_PORT_NUM_CPU),
> +			   RTL8366RB_PORT_ISO_PORTS(dsa_user_ports(ds))|

For beauty you can add the missing space here between ) and |.

> +			   RTL8366RB_PORT_ISO_EN);
> +	if (ret)
> +		return ret;
> +
>  	/* Set up the "green ethernet" feature */
>  	ret = rtl8366rb_jam_table(rtl8366rb_green_jam,
>  				  ARRAY_SIZE(rtl8366rb_green_jam), smi, false);
> @@ -1127,6 +1150,68 @@ rtl8366rb_port_disable(struct dsa_switch *ds, int port)
>  	rb8366rb_set_port_led(smi, port, false);
>  }
>  
> +static int
> +rtl8366rb_port_bridge_join(struct dsa_switch *ds, int port,
> +			   struct net_device *bridge)
> +{
> +	struct realtek_smi *smi = ds->priv;
> +	unsigned int port_bitmap = 0;
> +	int ret, i;
> +
> +	/* Loop over all other ports than this one */
> +	for (i = 0; i < RTL8366RB_PORT_NUM_CPU; i++) {
> +		/* Handled last */
> +		if (i == port)
> +			continue;
> +		/* Not on this bridge */
> +		if (dsa_to_port(ds, i)->bridge_dev != bridge)
> +			continue;
> +		/* Join this port to each other port on the bridge */
> +		ret = regmap_update_bits(smi->map, RTL8366RB_PORT_ISO(i),
> +					 RTL8366RB_PORT_ISO_PORTS(BIT(port)),
> +					 RTL8366RB_PORT_ISO_PORTS(BIT(port)));
> +		if (ret)
> +			return ret;
> +
> +		port_bitmap |= BIT(i);
> +	}
> +
> +	/* Set the bits for the ports we can access */
> +	return regmap_update_bits(smi->map, RTL8366RB_PORT_ISO(port),
> +				  RTL8366RB_PORT_ISO_PORTS_MASK,
> +				  RTL8366RB_PORT_ISO_PORTS(port_bitmap));
> +}
> +
> +static void
> +rtl8366rb_port_bridge_leave(struct dsa_switch *ds, int port,
> +			    struct net_device *bridge)
> +{
> +	struct realtek_smi *smi = ds->priv;
> +	unsigned int port_bitmap = 0;
> +	int ret, i;
> +
> +	/* Loop over all other ports than this one */
> +	for (i = 0; i < RTL8366RB_PORT_NUM_CPU; i++) {
> +		/* Handled last */
> +		if (i == port)
> +			continue;
> +		/* Not on this bridge */
> +		if (dsa_to_port(ds, i)->bridge_dev != bridge)
> +			continue;
> +		/* Remove this port from any other port on the bridge */
> +		ret = regmap_update_bits(smi->map, RTL8366RB_PORT_ISO(i),
> +					 RTL8366RB_PORT_ISO_PORTS(BIT(port)), 0);
> +		if (ret)
> +			return;

I don't think it is beneficial here to catch the error and return early?
We don't even have a print, it is a rather silent failure. I think if a
function that returns void fails, we should limp on and finish...
unbridging... the... port...

> +
> +		port_bitmap |= BIT(i);
> +	}
> +
> +	/* Clear the bits for the ports we can access */
> +	regmap_update_bits(smi->map, RTL8366RB_PORT_ISO(port),
> +			   RTL8366RB_PORT_ISO_PORTS(port_bitmap), 0);
> +}
> +
>  static int rtl8366rb_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
>  {
>  	struct realtek_smi *smi = ds->priv;
> @@ -1510,6 +1595,8 @@ static const struct dsa_switch_ops rtl8366rb_switch_ops = {
>  	.get_strings = rtl8366_get_strings,
>  	.get_ethtool_stats = rtl8366_get_ethtool_stats,
>  	.get_sset_count = rtl8366_get_sset_count,
> +	.port_bridge_join = rtl8366rb_port_bridge_join,
> +	.port_bridge_leave = rtl8366rb_port_bridge_leave,
>  	.port_vlan_filtering = rtl8366_vlan_filtering,
>  	.port_vlan_add = rtl8366_vlan_add,
>  	.port_vlan_del = rtl8366_vlan_del,
> -- 
> 2.31.1
>