Date: Tue, 12 Sep 2023 19:17:09 +0300
From: Vladimir Oltean <olteanv@...il.com>
To: Pawel Dembicki <paweldembicki@...il.com>
Cc: netdev@...r.kernel.org, Dan Carpenter <dan.carpenter@...aro.org>,
	Simon Horman <simon.horman@...igine.com>,
	Andrew Lunn <andrew@...n.ch>,
	Florian Fainelli <f.fainelli@...il.com>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Russell King <linux@...linux.org.uk>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next v3 5/8] net: dsa: vsc73xx: Add vlan filtering

On Tue, Sep 12, 2023 at 02:21:59PM +0200, Pawel Dembicki wrote:
> This patch implements VLAN filtering for the vsc73xx driver.
> 
> After starting VLAN filtering, the switch is reconfigured from QinQ to
> a simple VLAN aware mode. This is required because VSC73XX chips do not
> support inner VLAN tag filtering.
> 
> Signed-off-by: Pawel Dembicki <paweldembicki@...il.com>
> ---
> v3:
>   - reworked all vlan commits
>   - added storage variables for pvid and untagged vlans
>   - move length extender settings to port setup
>   - remove vlan table cleaning in wrong places
>   - note: dev_warn was keept because function 'vsc73xx_vlan_set_untagged'
>     and 'vsc73xx_vlan_set_pvid' are used later in tag implementation
> v2:
>   - no changes done
> 
>  drivers/net/dsa/vitesse-vsc73xx-core.c | 425 ++++++++++++++++++++++++-
>  drivers/net/dsa/vitesse-vsc73xx.h      |   2 +
>  2 files changed, 425 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/dsa/vitesse-vsc73xx-core.c b/drivers/net/dsa/vitesse-vsc73xx-core.c
> index 541fbc195df1..d9a6eac1fcce 100644
> --- a/drivers/net/dsa/vitesse-vsc73xx-core.c
> +++ b/drivers/net/dsa/vitesse-vsc73xx-core.c
> @@ -21,14 +21,18 @@
>  #include <linux/of_mdio.h>
>  #include <linux/bitops.h>
>  #include <linux/if_bridge.h>
> +#include <linux/if_vlan.h>
>  #include <linux/etherdevice.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/gpio/driver.h>
> +#include <linux/dsa/8021q.h>
>  #include <linux/random.h>
>  #include <net/dsa.h>
>  
>  #include "vitesse-vsc73xx.h"
>  
> +#define VSC73XX_IS_CONFIGURED	0x1
> +
>  #define VSC73XX_BLOCK_MAC	0x1 /* Subblocks 0-4, 6 (CPU port) */
>  #define VSC73XX_BLOCK_ANALYZER	0x2 /* Only subblock 0 */
>  #define VSC73XX_BLOCK_MII	0x3 /* Subblocks 0 and 1 */
> @@ -61,6 +65,8 @@
>  #define VSC73XX_CAT_DROP	0x6e
>  #define VSC73XX_CAT_PR_MISC_L2	0x6f
>  #define VSC73XX_CAT_PR_USR_PRIO	0x75
> +#define VSC73XX_CAT_VLAN_MISC	0x79
> +#define VSC73XX_CAT_PORT_VLAN	0x7a
>  #define VSC73XX_Q_MISC_CONF	0xdf
>  
>  /* MAC_CFG register bits */
> @@ -121,6 +127,17 @@
>  #define VSC73XX_ADVPORTM_IO_LOOPBACK	BIT(1)
>  #define VSC73XX_ADVPORTM_HOST_LOOPBACK	BIT(0)
>  
> +/*  TXUPDCFG transmit modify setup bits */
> +#define VSC73XX_TXUPDCFG_DSCP_REWR_MODE	GENMASK(20, 19)
> +#define VSC73XX_TXUPDCFG_DSCP_REWR_ENA	BIT(18)
> +#define VSC73XX_TXUPDCFG_TX_INT_TO_USRPRIO_ENA	BIT(17)
> +#define VSC73XX_TXUPDCFG_TX_UNTAGGED_VID	GENMASK(15, 4)
> +#define VSC73XX_TXUPDCFG_TX_UNTAGGED_VID_ENA	BIT(3)
> +#define VSC73XX_TXUPDCFG_TX_UPDATE_CRC_CPU_ENA	BIT(1)
> +#define VSC73XX_TXUPDCFG_TX_INSERT_TAG	BIT(0)
> +
> +#define VSC73XX_TXUPDCFG_TX_UNTAGGED_VID_SHIFT 4
> +
>  /* CAT_DROP categorizer frame dropping register bits */
>  #define VSC73XX_CAT_DROP_DROP_MC_SMAC_ENA	BIT(6)
>  #define VSC73XX_CAT_DROP_FWD_CTRL_ENA		BIT(4)
> @@ -134,6 +151,15 @@
>  #define VSC73XX_Q_MISC_CONF_EARLY_TX_512	(1 << 1)
>  #define VSC73XX_Q_MISC_CONF_MAC_PAUSE_MODE	BIT(0)
>  
> +/* CAT_VLAN_MISC categorizer VLAN miscellaneous bits*/
> +#define VSC73XX_CAT_VLAN_MISC_VLAN_TCI_IGNORE_ENA BIT(8)
> +#define VSC73XX_CAT_VLAN_MISC_VLAN_KEEP_TAG_ENA BIT(7)
> +
> +/* CAT_PORT_VLAN categorizer port VLAN*/
> +#define VSC73XX_CAT_PORT_VLAN_VLAN_CFI BIT(15)
> +#define VSC73XX_CAT_PORT_VLAN_VLAN_USR_PRIO GENMASK(14, 12)
> +#define VSC73XX_CAT_PORT_VLAN_VLAN_VID GENMASK(11, 0)
> +
>  /* Frame analyzer block 2 registers */
>  #define VSC73XX_STORMLIMIT	0x02
>  #define VSC73XX_ADVLEARN	0x03
> @@ -188,7 +214,8 @@
>  #define VSC73XX_VLANACCESS_VLAN_MIRROR		BIT(29)
>  #define VSC73XX_VLANACCESS_VLAN_SRC_CHECK	BIT(28)
>  #define VSC73XX_VLANACCESS_VLAN_PORT_MASK	GENMASK(9, 2)
> -#define VSC73XX_VLANACCESS_VLAN_TBL_CMD_MASK	GENMASK(2, 0)
> +#define VSC73XX_VLANACCESS_VLAN_PORT_MASK_SHIFT	2
> +#define VSC73XX_VLANACCESS_VLAN_TBL_CMD_MASK	GENMASK(1, 0)
>  #define VSC73XX_VLANACCESS_VLAN_TBL_CMD_IDLE	0
>  #define VSC73XX_VLANACCESS_VLAN_TBL_CMD_READ_ENTRY	1
>  #define VSC73XX_VLANACCESS_VLAN_TBL_CMD_WRITE_ENTRY	2
> @@ -343,6 +370,11 @@ static const struct vsc73xx_counter vsc73xx_tx_counters[] = {
>  	{ 29, "TxQoSClass3" }, /* non-standard counter */
>  };
>  
> +enum vsc73xx_port_vlan_conf {
> +	VSC73XX_VLAN_FILTER,
> +	VSC73XX_VLAN_IGNORE,
> +};
> +
>  int vsc73xx_is_addr_valid(u8 block, u8 subblock)
>  {
>  	switch (block) {
> @@ -563,7 +595,7 @@ static enum dsa_tag_protocol vsc73xx_get_tag_protocol(struct dsa_switch *ds,
>  static int vsc73xx_setup(struct dsa_switch *ds)
>  {
>  	struct vsc73xx *vsc = ds->priv;
> -	int i;
> +	int i, ret;

../drivers/net/dsa/vitesse-vsc73xx-core.c:598:9: warning: unused variable 'ret' [-Wunused-variable]
        int i, ret;
               ^

>  
>  	dev_info(vsc->dev, "set up the switch\n");
>  
> @@ -623,6 +655,9 @@ static int vsc73xx_setup(struct dsa_switch *ds)
>  	vsc73xx_write(vsc, VSC73XX_BLOCK_SYSTEM, 0, VSC73XX_GMIIDELAY,
>  		      VSC73XX_GMIIDELAY_GMII0_GTXDELAY_2_0_NS |
>  		      VSC73XX_GMIIDELAY_GMII0_RXDELAY_2_0_NS);
> +	/* Ingess VLAN reception mask (table 145) */
> +	vsc73xx_write(vsc, VSC73XX_BLOCK_ANALYZER, 0, VSC73XX_VLANMASK,
> +		      0x5f);
>  	/* IP multicast flood mask (table 144) */
>  	vsc73xx_write(vsc, VSC73XX_BLOCK_ANALYZER, 0, VSC73XX_IFLODMSK,
>  		      0xff);
> @@ -1031,8 +1066,387 @@ static int vsc73xx_get_max_mtu(struct dsa_switch *ds, int port)
>  	return 9600 - ETH_HLEN - ETH_FCS_LEN;
>  }
>  
> +static int vsc73xx_wait_for_vlan_table_cmd(struct vsc73xx *vsc)
> +{
> +	int ret, err;
> +	u32 val;
> +
> +	ret = read_poll_timeout(vsc73xx_read, err,
> +				err < 0 || ((val & VSC73XX_VLANACCESS_VLAN_TBL_CMD_MASK) ==
> +					    VSC73XX_VLANACCESS_VLAN_TBL_CMD_IDLE),
> +				1000, 10000, false, vsc, VSC73XX_BLOCK_ANALYZER,
> +				0, VSC73XX_VLANACCESS, &val);
> +	if (ret)
> +		return ret;
> +	return err;
> +}
> +
> +static int
> +vsc73xx_read_vlan_table_entry(struct vsc73xx *vsc, u16 vid, u8 *portmap)
> +{
> +	u32 val;
> +	int ret;
> +
> +	vsc73xx_write(vsc, VSC73XX_BLOCK_ANALYZER, 0, VSC73XX_VLANTIDX, vid);
> +	ret = vsc73xx_wait_for_vlan_table_cmd(vsc);
> +	if (ret)
> +		return ret;
> +	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_ANALYZER, 0, VSC73XX_VLANACCESS,
> +			    VSC73XX_VLANACCESS_VLAN_TBL_CMD_MASK,
> +			    VSC73XX_VLANACCESS_VLAN_TBL_CMD_READ_ENTRY);
> +	ret = vsc73xx_wait_for_vlan_table_cmd(vsc);
> +	if (ret)
> +		return ret;
> +	vsc73xx_read(vsc, VSC73XX_BLOCK_ANALYZER, 0, VSC73XX_VLANACCESS, &val);
> +	*portmap = (val & VSC73XX_VLANACCESS_VLAN_PORT_MASK) >>
> +		   VSC73XX_VLANACCESS_VLAN_PORT_MASK_SHIFT;
> +	return 0;
> +}
> +
> +static int
> +vsc73xx_write_vlan_table_entry(struct vsc73xx *vsc, u16 vid, u8 portmap)
> +{
> +	int ret;
> +
> +	vsc73xx_write(vsc, VSC73XX_BLOCK_ANALYZER, 0, VSC73XX_VLANTIDX, vid);
> +	ret = vsc73xx_wait_for_vlan_table_cmd(vsc);
> +	if (ret)
> +		return ret;
> +
> +	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_ANALYZER, 0, VSC73XX_VLANACCESS,
> +			    VSC73XX_VLANACCESS_VLAN_TBL_CMD_MASK |
> +			    VSC73XX_VLANACCESS_VLAN_SRC_CHECK |
> +			    VSC73XX_VLANACCESS_VLAN_PORT_MASK,
> +			    VSC73XX_VLANACCESS_VLAN_TBL_CMD_WRITE_ENTRY |
> +			    VSC73XX_VLANACCESS_VLAN_SRC_CHECK |
> +			    (portmap <<
> +			     VSC73XX_VLANACCESS_VLAN_PORT_MASK_SHIFT));
> +
> +	return vsc73xx_wait_for_vlan_table_cmd(vsc);
> +}
> +
> +static int
> +vsc73xx_update_vlan_table(struct vsc73xx *vsc, int port, u16 vid, bool set)
> +{
> +	u8 portmap;
> +	int ret;
> +
> +	ret = vsc73xx_read_vlan_table_entry(vsc, vid, &portmap);
> +	if (ret)
> +		return ret;
> +
> +	if (set)
> +		portmap |= BIT(port) | BIT(CPU_PORT);
> +	else
> +		portmap &= ~BIT(port);
> +
> +	if (portmap == BIT(CPU_PORT))
> +		portmap = 0;

Why did you need to do this? To my knowledge, the DSA framework code
will decide when to remove VLANs from the CPU port.

> +
> +	return  vsc73xx_write_vlan_table_entry(vsc, vid, portmap);
> +}
> +
> +static void
> +vsc73xx_set_vlan_conf(struct vsc73xx *vsc, int port,
> +		      enum vsc73xx_port_vlan_conf port_vlan_conf)
> +{
> +	if (port_vlan_conf == VSC73XX_VLAN_IGNORE) {
> +		vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
> +				    VSC73XX_CAT_VLAN_MISC,
> +				    VSC73XX_CAT_VLAN_MISC_VLAN_TCI_IGNORE_ENA,
> +				    VSC73XX_CAT_VLAN_MISC_VLAN_TCI_IGNORE_ENA);

IMO this, and all the other places that write the same registers from 2
branches, would look less clutered like this:

	u32 val;

	val = (port_vlan_conf == VSC73XX_VLAN_IGNORE) ?
	      VSC73XX_CAT_VLAN_MISC_VLAN_KEEP_TAG_ENA : 0;

	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_CAT_VLAN_MISC,
			    VSC73XX_CAT_VLAN_MISC_VLAN_KEEP_TAG_ENA, val);

	val = ...

Otherwise, the larger the branches become, the harder it gets to see
what's common and what's different.

> +		vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
> +				    VSC73XX_CAT_VLAN_MISC,
> +				    VSC73XX_CAT_VLAN_MISC_VLAN_KEEP_TAG_ENA,
> +				    VSC73XX_CAT_VLAN_MISC_VLAN_KEEP_TAG_ENA);
> +		vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
> +				    VSC73XX_TXUPDCFG,
> +				    VSC73XX_TXUPDCFG_TX_INSERT_TAG, 0);
> +	} else {
> +		vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
> +				    VSC73XX_CAT_VLAN_MISC,
> +				    VSC73XX_CAT_VLAN_MISC_VLAN_TCI_IGNORE_ENA,
> +				    0);
> +		vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
> +				    VSC73XX_CAT_VLAN_MISC,
> +				    VSC73XX_CAT_VLAN_MISC_VLAN_KEEP_TAG_ENA, 0);
> +		vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
> +				    VSC73XX_TXUPDCFG,
> +				    VSC73XX_TXUPDCFG_TX_INSERT_TAG,
> +				    VSC73XX_TXUPDCFG_TX_INSERT_TAG);
> +	}
> +}
> +
> +static int
> +vsc73xx_vlan_change_untagged(struct vsc73xx *vsc, int port, u16 vid, bool set)
> +{
> +	u32 val = set ? VSC73XX_TXUPDCFG_TX_UNTAGGED_VID_ENA : 0;
> +
> +	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_TXUPDCFG,
> +			    VSC73XX_TXUPDCFG_TX_UNTAGGED_VID_ENA, val);
> +	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_TXUPDCFG,
> +			    VSC73XX_TXUPDCFG_TX_UNTAGGED_VID,
> +			    (vid << VSC73XX_TXUPDCFG_TX_UNTAGGED_VID_SHIFT) &
> +			     VSC73XX_TXUPDCFG_TX_UNTAGGED_VID);
> +	return 0;
> +}
> +
> +static int
> +vsc73xx_vlan_change_pvid(struct vsc73xx *vsc, int port, u16 vid, bool set)

Would it simplify callers to add a "bool operate_on_storage" argument here,
and absorb that logic? The callers could look like this, notice how there is
less code duplication between the "if" and "else" branches.

static int vsc73xx_vlan_set_pvid(struct dsa_switch *ds, int port, u16 vid,
				 bool tag_8021q_vlan)
{
	struct dsa_port *dp = dsa_to_port(ds, port);
	struct vsc73xx *vsc = ds->priv;
	bool operate_on_storage;
	u16 existing_pvid;
	bool had_pvid;

	operate_on_storage = vsc73xx_tag_8021q_active(dp) ^ tag_8021q_vlan;

	had_pvid = vsc73xx_port_get_pvid(vsc, port, &existing_pvid,
					 &operate_on_storage);
	if (had_pvid && existing_pvid != vid) {
		dev_warn(vsc->dev,
			 "Port %d can have only one pvid! Now is: %d.\n",
			 port, existing_pvid);
		return -EOPNOTSUPP;
	}

	return vsc73xx_vlan_change_pvid(vsc, port, vid, true, operate_on_storage);
}

> +{
> +	u32 val = set ? 0 : VSC73XX_CAT_DROP_UNTAGGED_ENA;
> +
> +	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_CAT_DROP,
> +			    VSC73XX_CAT_DROP_UNTAGGED_ENA, val);
> +
> +	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_CAT_PORT_VLAN,
> +			    VSC73XX_CAT_PORT_VLAN_VLAN_VID,
> +			    vid & VSC73XX_CAT_PORT_VLAN_VLAN_VID);
> +	return 0;
> +}
> +
> +static int vsc73xx_vlan_port_is_pvid(struct vsc73xx *vsc, int port, u16 *vid)

I believe it would look better if this would return bool, and if it had
a shorter name (vsc73xx_port_get_pvid).

> +{
> +	u32 val;
> +
> +	vsc73xx_read(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_CAT_DROP, &val);
> +	if (val & VSC73XX_CAT_DROP_UNTAGGED_ENA)
> +		return 0;
> +
> +	vsc73xx_read(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_CAT_PORT_VLAN, &val);
> +	*vid = val & VSC73XX_CAT_PORT_VLAN_VLAN_VID;
> +
> +	return VSC73XX_IS_CONFIGURED;
> +}
> +
> +static int vsc73xx_vlan_port_is_untagged(struct vsc73xx *vsc, int port, u16 *vid)
> +{
> +	u32 val;
> +
> +	vsc73xx_read(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_TXUPDCFG, &val);
> +	if (!(val & VSC73XX_TXUPDCFG_TX_UNTAGGED_VID_ENA))
> +		return 0;
> +
> +	vsc73xx_read(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_TXUPDCFG,
> +		     &val);

Don't need to read the same register twice.

> +	*vid = (val & VSC73XX_TXUPDCFG_TX_UNTAGGED_VID) >>
> +		VSC73XX_TXUPDCFG_TX_UNTAGGED_VID_SHIFT;
> +
> +	return VSC73XX_IS_CONFIGURED;
> +}
> +
> +static int vsc73xx_vlan_set_untagged(struct dsa_switch *ds, int port, u16 vid,
> +				     bool port_vlan)
> +{
> +	struct vsc73xx *vsc = ds->priv;
> +	u16 vlan_no = 0;
> +
> +	if (dsa_port_is_vlan_filtering(dsa_to_port(ds, port)) ^ port_vlan) {

I think it would be valuable for readability to create a helper function named:

static bool vsc73xx_tag_8021q_active(struct dsa_port *dp)
{
	return !dsa_port_is_vlan_filtering(dp);
}

and then, to rename "port_vlan" to "!tag_8021q_vlan". It would make it
clearer as to what the checks are about.

	if (vsc73xx_tag_8021q_active(dp) ^ tag_8021q_vlan) {
		// update cached storage
	} else {
		// update hardware
	}

> +		if (vsc->untagged_storage[port] < VLAN_N_VID &&
> +		    !vid_is_dsa_8021q(vsc->untagged_storage[port]) &&
> +		    !vid_is_dsa_8021q(vid) &&

The problem here which led to these vid_is_dsa_8021q() checks is that
dsa_switch_tag_8021q_vlan_add() sets all flags on user ports to
BRIDGE_VLAN_INFO_UNTAGGED | BRIDGE_VLAN_INFO_PVID, and you can't offload
those, correct? But when the port is VSC73XX_VLAN_IGNORE mode (and
tag_8021q is active), VSC73XX_TXUPDCFG_TX_INSERT_TAG is 0, and thus,
*all* VLANs are egress-untagged VLANs, correct?

If that is the case, why do you call vsc73xx_vlan_set_untagged() in the
first place, for tag_8021q VLANs, if you don't rely on the port's native
VLAN for egress untagging?

> +		    vsc->untagged_storage[port] != vid) {
> +			dev_warn(vsc->dev,
> +				 "Port %d can have only one untagged vid! Now is: %d.\n",
> +				 port, vsc->untagged_storage[port]);
> +			return -EOPNOTSUPP;
> +		}
> +		vsc->untagged_storage[port] = vid;
> +	} else {
> +		if (vsc73xx_vlan_port_is_untagged(vsc, port, &vlan_no) == VSC73XX_IS_CONFIGURED &&
> +		    !vid_is_dsa_8021q(vlan_no) && !vid_is_dsa_8021q(vid) && vlan_no != vid) {
> +			dev_warn(vsc->dev,
> +				 "Port %d can have only one untagged vid! Now is: %d.\n",
> +				 port, vlan_no);
> +			return -EOPNOTSUPP;
> +		}
> +		return vsc73xx_vlan_change_untagged(vsc, port, vid, 1);
> +	}
> +
> +	return 0;
> +}
> +
> +static int vsc73xx_vlan_set_pvid(struct dsa_switch *ds, int port, u16 vid,
> +				 bool port_vlan)
> +{
> +	struct dsa_port *dsa_port = dsa_to_port(ds, port);
> +	struct vsc73xx *vsc = ds->priv;
> +	u16 vlan_no;
> +
> +	if (!dsa_port)
> +		return -EINVAL;

Why is this check here?

> +
> +	if (dsa_port_is_vlan_filtering(dsa_port) ^ port_vlan) {
> +		if (vsc->pvid_storage[port] < VLAN_N_VID &&
> +		    !vid_is_dsa_8021q(vsc->pvid_storage[port]) &&
> +		    !vid_is_dsa_8021q(vid) && vsc->pvid_storage[port] != vid) {

What are the vid_is_dsa_8021q() checks for?

> +			dev_warn(vsc->dev,
> +				 "Port %d can have only one pvid! Now is: %d.\n",
> +				 port, vsc->pvid_storage[port]);
> +			return -EOPNOTSUPP;
> +		}
> +		vsc->pvid_storage[port] = vid;
> +	} else {
> +		if (vsc73xx_vlan_port_is_pvid(vsc, port, &vlan_no) == VSC73XX_IS_CONFIGURED &&
> +		    !vid_is_dsa_8021q(vlan_no) && !vid_is_dsa_8021q(vid) &&
> +		    vlan_no != vid) {
> +			dev_warn(vsc->dev,
> +				 "Port %d can have only one pvid! Now is: %d.\n",
> +				 port, vlan_no);
> +			return -EOPNOTSUPP;
> +		}
> +		return vsc73xx_vlan_change_pvid(vsc, port, vid, 1);
> +	}
> +
> +	return 0;
> +}
> +
> +static int
> +vsc73xx_port_vlan_filtering(struct dsa_switch *ds, int port,
> +			    bool vlan_filtering, struct netlink_ext_ack *extack)

A comment would be good which states that the flipping between the
hardware and the storage values relies on the fact that vsc73xx_port_vlan_filtering()
only gets called on actual changes to vlan_filtering, and thus, to
vsc73xx_tag_8021q_active(). So, we know for sure that what is in storage
needs to go to hardware, and what is in hardware needs to go to storage.

It's an interesting implementation for sure.

> +{
> +	struct vsc73xx *vsc = ds->priv;
> +	bool store_untagged  = false;
> +	bool store_pvid  = false;

nit: replace the 2 spaces before the "=" with a single one.

> +	u16 vlan_no;
> +
> +	if (vlan_filtering)
> +		vsc73xx_set_vlan_conf(vsc, port, VSC73XX_VLAN_FILTER);
> +	else
> +		vsc73xx_set_vlan_conf(vsc, port, VSC73XX_VLAN_IGNORE);
> +
> +	if (vsc73xx_vlan_port_is_pvid(vsc, port, &vlan_no) == VSC73XX_IS_CONFIGURED)
> +		store_pvid = true;
> +
> +	if (vsc->pvid_storage[port] < VLAN_N_VID)
> +		vsc73xx_vlan_change_pvid(vsc, port, vsc->pvid_storage[port], true);
> +	else
> +		vsc73xx_vlan_change_pvid(vsc, port, 0, false);
> +
> +	vsc->pvid_storage[port] = store_pvid ? vlan_no : VLAN_N_VID;
> +
> +	if (vsc73xx_vlan_port_is_untagged(vsc, port, &vlan_no) == VSC73XX_IS_CONFIGURED)
> +		store_untagged  = true;
> +
> +	if (vsc->untagged_storage[port] < VLAN_N_VID)
> +		vsc73xx_vlan_change_untagged(vsc, port, vsc->untagged_storage[port], true);
> +	else
> +		vsc73xx_vlan_change_untagged(vsc, port, 0, false);
> +
> +	vsc->untagged_storage[port] = store_untagged ? vlan_no : VLAN_N_VID;
> +
> +	return 0;
> +}
> +
> +static int vsc73xx_port_vlan_add(struct dsa_switch *ds, int port,
> +				 const struct switchdev_obj_port_vlan *vlan,
> +				 struct netlink_ext_ack *extack)
> +{
> +	bool untagged = vlan->flags & BRIDGE_VLAN_INFO_UNTAGGED;
> +	bool pvid = vlan->flags & BRIDGE_VLAN_INFO_PVID;
> +	struct vsc73xx *vsc = ds->priv;
> +	u16 vlan_no;
> +	int ret;
> +
> +	/* Be sure to deny alterations to the configuration done by tag_8021q.
> +	 */
> +	if (vid_is_dsa_8021q(vlan->vid)) {
> +		NL_SET_ERR_MSG_MOD(extack,
> +				   "Range 3072-4095 reserved for dsa_8021q operation");
> +		return -EBUSY;
> +	}
> +
> +	if (port != CPU_PORT) {
> +		if (untagged) {
> +			ret = vsc73xx_vlan_set_untagged(ds, port, vlan->vid, true);
> +			if (ret)
> +				return ret;
> +		} else {
> +			if (vsc73xx_vlan_port_is_untagged(vsc, port, &vlan_no)
> +			    == VSC73XX_IS_CONFIGURED &&
> +			    vlan_no == vlan->vid)
> +				vsc73xx_vlan_change_untagged(vsc, port, 0, false);
> +			else if (vsc->untagged_storage[port] == vlan->vid)
> +				vsc->untagged_storage[port] = VLAN_N_VID;
> +		}
> +		if (pvid) {
> +			ret = vsc73xx_vlan_set_pvid(ds, port, vlan->vid, true);
> +			if (ret)
> +				return ret;
> +		} else {
> +			if (vsc73xx_vlan_port_is_pvid(vsc, port, &vlan_no)
> +			    == VSC73XX_IS_CONFIGURED &&
> +			    vlan_no == vlan->vid)
> +				vsc73xx_vlan_change_pvid(vsc, port, 0, false);
> +			else if (vsc->pvid_storage[port] == vlan->vid)
> +				vsc->pvid_storage[port] = VLAN_N_VID;
> +		}
> +	}
> +
> +	return vsc73xx_update_vlan_table(vsc, port, vlan->vid, 1);

last argument is bool, so pass true or false (here and everywhere else)

> +}
> +
> +static int vsc73xx_port_vlan_del(struct dsa_switch *ds, int port,
> +				 const struct switchdev_obj_port_vlan *vlan)
> +{
> +	struct vsc73xx *vsc = ds->priv;
> +	u16 vlan_no;
> +	int ret;
> +
> +	ret = vsc73xx_update_vlan_table(vsc, port, vlan->vid, 0);
> +	if (ret)
> +		return ret;
> +
> +	if (vsc73xx_vlan_port_is_untagged(vsc, port, &vlan_no) == VSC73XX_IS_CONFIGURED &&
> +	    vlan_no == vlan->vid)
> +		vsc73xx_vlan_change_untagged(vsc, port, 0, false);
> +	else if (vsc->untagged_storage[port] == vlan->vid)
> +		vsc->untagged_storage[port] = VLAN_N_VID;
> +
> +	if (vsc73xx_vlan_port_is_pvid(vsc, port, &vlan_no) == VSC73XX_IS_CONFIGURED &&
> +	    vlan_no == vlan->vid)
> +		vsc73xx_vlan_change_pvid(vsc, port, 0, false);
> +	else if (vsc->pvid_storage[port] == vlan->vid)
> +		vsc->pvid_storage[port] = VLAN_N_VID;
> +
> +	return 0;
> +}
> +
>  static int vsc73xx_port_setup(struct dsa_switch *ds, int port)
>  {
> +	struct vsc73xx *vsc = ds->priv;
> +	int ret, i;
> +
> +	/* Those bits are responsible for MTU only. Kernel take care about MTU,
> +	 * let's enable +8 bytes frame length unconditionally.
> +	 */
> +	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_MAC_CFG,
> +			    VSC73XX_MAC_CFG_VLAN_AWR | VSC73XX_MAC_CFG_VLAN_DBLAWR,
> +			    VSC73XX_MAC_CFG_VLAN_AWR | VSC73XX_MAC_CFG_VLAN_DBLAWR);
> +
> +	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_CAT_DROP,
> +			    VSC73XX_CAT_DROP_TAGGED_ENA, 0);
> +	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_CAT_DROP,
> +			    VSC73XX_CAT_DROP_UNTAGGED_ENA,
> +			    VSC73XX_CAT_DROP_UNTAGGED_ENA);
> +	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_TXUPDCFG,
> +			    VSC73XX_TXUPDCFG_TX_UNTAGGED_VID_ENA, 0);
> +	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_TXUPDCFG,
> +			    VSC73XX_TXUPDCFG_TX_UNTAGGED_VID, 0);
> +	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_CAT_PORT_VLAN,
> +			    VSC73XX_CAT_PORT_VLAN_VLAN_VID, 0);
> +
> +	if (port == CPU_PORT)
> +		vsc73xx_set_vlan_conf(vsc, port, VSC73XX_VLAN_FILTER);
> +	else
> +		vsc73xx_set_vlan_conf(vsc, port, VSC73XX_VLAN_IGNORE);
> +
> +	for (i = 0; i <= VLAN_N_VID; i++) {

VLAN_N_VID is 4096, so i <= VLAN_N_VID must be a mistake?

> +		ret = vsc73xx_update_vlan_table(vsc, port, i, 0);
> +		if (ret)
> +			return ret;
> +	}

Also, could you write an expedited version of this, which is not called
from ds->ops->port_setup() but from ds->ops->setup()? It is wasteful to
traverse the VLAN table for each port, when we know from the get go that
we need to clear all ports.

> +
>  	/* Configure forward map to CPU <-> port only */
>  	if (port == CPU_PORT)
>  		vsc->forward_map[CPU_PORT] = VSC73XX_SRCMASKS_PORTS_MASK &
> @@ -1041,6 +1455,10 @@ static int vsc73xx_port_setup(struct dsa_switch *ds, int port)
>  		vsc->forward_map[port] = VSC73XX_SRCMASKS_PORTS_MASK &
>  					 BIT(CPU_PORT);
>  
> +	/* Set storage values out of range*/

Nit: Space after "*/" (there are a few other places left which have
this style issue)

> +	vsc->pvid_storage[port] = VLAN_N_VID;
> +	vsc->untagged_storage[port] = VLAN_N_VID;
> +
>  	return 0;
>  }
>  
> @@ -1098,6 +1516,9 @@ static const struct dsa_switch_ops vsc73xx_ds_ops = {
>  	.port_change_mtu = vsc73xx_change_mtu,
>  	.port_max_mtu = vsc73xx_get_max_mtu,
>  	.port_stp_state_set = vsc73xx_port_stp_state_set,
> +	.port_vlan_filtering = vsc73xx_port_vlan_filtering,
> +	.port_vlan_add = vsc73xx_port_vlan_add,
> +	.port_vlan_del = vsc73xx_port_vlan_del,
>  };
>  
>  static int vsc73xx_gpio_get(struct gpio_chip *chip, unsigned int offset)
> diff --git a/drivers/net/dsa/vitesse-vsc73xx.h b/drivers/net/dsa/vitesse-vsc73xx.h
> index 224e284a5573..b7614dd7d0eb 100644
> --- a/drivers/net/dsa/vitesse-vsc73xx.h
> +++ b/drivers/net/dsa/vitesse-vsc73xx.h
> @@ -30,6 +30,8 @@ struct vsc73xx {
>  	const struct vsc73xx_ops	*ops;
>  	void				*priv;
>  	u8				forward_map[VSC73XX_MAX_NUM_PORTS];
> +	u16				pvid_storage[VSC73XX_MAX_NUM_PORTS];
> +	u16				untagged_storage[VSC73XX_MAX_NUM_PORTS];
>  };
>  
>  struct vsc73xx_ops {
> -- 
> 2.34.1
> 

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