Re: [PATCH net-next v2] net: dsa: qca8k: Add 802.1q VLAN support

Vladimir Oltean
2020-07-28T16:35:28Z

Hi Jonathan,

On Sun, Jul 26, 2020 at 03:56:11PM +0100, Jonathan McDowell wrote:
> This adds full 802.1q VLAN support to the qca8k, allowing the use of
> vlan_filtering and more complicated bridging setups than allowed by
> basic port VLAN support.
>
> Tested with a number of untagged ports with separate VLANs and then a
> trunk port with all the VLANs tagged on it.
>
> v2:
> - Return sensible errnos on failure rather than -1 (rmk)
> - Style cleanups based on Florian's feedback
> - Silently allow VLAN 0 as device correctly treats this as no tag
>
> Signed-off-by: Jonathan McDowell <noodles@earth.li>
> ---

This generally looks ok. The integration with the APIs is fine.
Some comments below.

> drivers/net/dsa/qca8k.c | 191 ++++++++++++++++++++++++++++++++++++++--
> drivers/net/dsa/qca8k.h | 28 ++++++
> 2 files changed, 214 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
> index a5566de82853..1cc61bc8929f 100644
> --- a/drivers/net/dsa/qca8k.c
> +++ b/drivers/net/dsa/qca8k.c
> @@ -408,6 +408,111 @@ qca8k_fdb_flush(struct qca8k_priv *priv)
> mutex_unlock(&priv->reg_mutex);
> }
>
> +static int
> +qca8k_vlan_access(struct qca8k_priv *priv, enum qca8k_vlan_cmd cmd, u16 vid)
> +{
> + u32 reg;
> +
> + /* Set the command and VLAN index */
> + reg = QCA8K_VTU_FUNC1_BUSY;
> + reg |= cmd;
> + reg |= vid << QCA8K_VTU_FUNC1_VID_S;
> +
> + /* Write the function register triggering the table access */
> + qca8k_write(priv, QCA8K_REG_VTU_FUNC1, reg);
> +
> + /* wait for completion */
> + if (qca8k_busy_wait(priv, QCA8K_REG_VTU_FUNC1, QCA8K_VTU_FUNC1_BUSY))
> + return -ETIMEDOUT;
> +
> + /* Check for table full violation when adding an entry */
> + if (cmd == QCA8K_VLAN_LOAD) {
> + reg = qca8k_read(priv, QCA8K_REG_VTU_FUNC1);
> + if (reg & QCA8K_VTU_FUNC1_FULL)
> + return -ENOMEM;
> + }
> +
> + return 0;
> +}
> +
> +static int
> +qca8k_vlan_add(struct qca8k_priv *priv, u8 port, u16 vid, bool tagged)

It is customary to keep referring to this bool as 'untagged' for
consistency with many other parts of the kernel.

> +{
> + u32 reg;
> + int ret;
> +
> + /* We do the right thing with VLAN 0 and treat it as untagged */

...while also preserving the tag on egress.

> + if (vid == 0)
> + return 0;
> +
> + mutex_lock(&priv->reg_mutex);

Unrelated, but what's the purpose of this mutex?

> + ret = qca8k_vlan_access(priv, QCA8K_VLAN_READ, vid);
> + if (ret < 0)
> + goto out;
> +
> + reg = qca8k_read(priv, QCA8K_REG_VTU_FUNC0);
> + reg |= QCA8K_VTU_FUNC0_VALID | QCA8K_VTU_FUNC0_IVL_EN;
> + reg &= ~(3 << QCA8K_VTU_FUNC0_EG_MODE_S(port));
> + if (tagged)
> + reg |= QCA8K_VTU_FUNC0_EG_MODE_TAG <<
> + QCA8K_VTU_FUNC0_EG_MODE_S(port);
> + else
> + reg |= QCA8K_VTU_FUNC0_EG_MODE_UNTAG <<
> + QCA8K_VTU_FUNC0_EG_MODE_S(port);
> +

Not thrilled about the "3 <<" thing, maybe a definition like the one
below would look better:

#define QCA8K_VTU_FUNC_REG0_EG_VLAN_MODE_MASK(port) \
GENMASK(5 + (port) * 2, 4 + (port) * 2)

...

int eg_vlan_mode = QCA8K_VTU_FUNC_REG0_EG_MODE_TAG;

reg &= ~QCA8K_VTU_FUNC_REG0_EG_VLAN_MODE_MASK(port);
if (tagged)
eg_vlan_mode = QCA8K_VTU_FUNC_REG0_EG_MODE_UNTAG;
reg |= QCA8K_VTU_FUNC_REG0_EG_MODE(eg_vlan_mode, port);

Your call if you want to change this, though.

> + qca8k_write(priv, QCA8K_REG_VTU_FUNC0, reg);
> + ret = qca8k_vlan_access(priv, QCA8K_VLAN_LOAD, vid);
> +
> +out:
> + mutex_unlock(&priv->reg_mutex);
> +
> + return ret;
> +}
> +
> +static int
> +qca8k_vlan_del(struct qca8k_priv *priv, u8 port, u16 vid)
> +{
> + u32 reg;
> + u32 mask;
> + int ret;
> + int i;
> + bool del;

How about:

u32 reg, mask;
int ret, i;
bool del;

> +
> + mutex_lock(&priv->reg_mutex);
> + ret = qca8k_vlan_access(priv, QCA8K_VLAN_READ, vid);
> + if (ret < 0)
> + goto out;
> +
> + reg = qca8k_read(priv, QCA8K_REG_VTU_FUNC0);
> + reg &= ~(3 << QCA8K_VTU_FUNC0_EG_MODE_S(port));
> + reg |= QCA8K_VTU_FUNC0_EG_MODE_NOT <<
> + QCA8K_VTU_FUNC0_EG_MODE_S(port);
> +
> + /* Check if we're the last member to be removed */
> + del = true;
> + for (i = 0; i < QCA8K_NUM_PORTS; i++) {
> + mask = QCA8K_VTU_FUNC0_EG_MODE_NOT;
> + mask <<= QCA8K_VTU_FUNC0_EG_MODE_S(i);
> +
> + if ((reg & mask) != mask) {
> + del = false;
> + break;
> + }
> + }
> +
> + if (del) {
> + ret = qca8k_vlan_access(priv, QCA8K_VLAN_PURGE, vid);
> + } else {
> + qca8k_write(priv, QCA8K_REG_VTU_FUNC0, reg);
> + ret = qca8k_vlan_access(priv, QCA8K_VLAN_LOAD, vid);
> + }
> +
> +out:
> + mutex_unlock(&priv->reg_mutex);
> +
> + return ret;
> +}
> +
> static void
> qca8k_mib_init(struct qca8k_priv *priv)
> {
> @@ -663,10 +768,11 @@ qca8k_setup(struct dsa_switch *ds)
> * default egress vid
> */
> qca8k_rmw(priv, QCA8K_EGRESS_VLAN(i),
> - 0xffff << shift, 1 << shift);
> + 0xffff << shift,
> + QCA8K_PORT_VID_DEF << shift);

This has telltale signs of copy-pasted code. ROUTER_DEFAULT_VID is a
12-bit register, so 0xffff is probably not the right mask. But, it is
true that the upper 4 bits are reserved, so it isn't quite a bug to
zero them out, just something that sticks out as not correct.

> qca8k_write(priv, QCA8K_REG_PORT_VLAN_CTRL0(i),
> - QCA8K_PORT_VLAN_CVID(1) |
> - QCA8K_PORT_VLAN_SVID(1));
> + QCA8K_PORT_VLAN_CVID(QCA8K_PORT_VID_DEF) |
> + QCA8K_PORT_VLAN_SVID(QCA8K_PORT_VID_DEF));
> }
> }
>
> @@ -1133,7 +1239,7 @@ qca8k_port_fdb_insert(struct qca8k_priv *priv, const u8 *addr,
> {
> /* Set the vid to the port vlan id if no vid is set */
> if (!vid)
> - vid = 1;
> + vid = QCA8K_PORT_VID_DEF;
>
> return qca8k_fdb_add(priv, addr, port_mask, vid,
> QCA8K_ATU_STATUS_STATIC);
> @@ -1157,7 +1263,7 @@ qca8k_port_fdb_del(struct dsa_switch *ds, int port,
> u16 port_mask = BIT(port);
>
> if (!vid)
> - vid = 1;
> + vid = QCA8K_PORT_VID_DEF;

Maybe you could split out this s/1/QCA8K_PORT_VID_DEF/g patch into a
separate one? For the purpose of the introduction of VLAN callbacks,
it's just noise.

>
> return qca8k_fdb_del(priv, addr, port_mask, vid);
> }
> @@ -1186,6 +1292,76 @@ qca8k_port_fdb_dump(struct dsa_switch *ds, int port,
> return 0;
> }
>
> +static int
> +qca8k_port_vlan_filtering(struct dsa_switch *ds, int port, bool vlan_filtering)
> +{
> + struct qca8k_priv *priv = ds->priv;
> +
> + if (vlan_filtering) {
> + qca8k_rmw(priv, QCA8K_PORT_LOOKUP_CTRL(port),
> + QCA8K_PORT_LOOKUP_VLAN_MODE,
> + QCA8K_PORT_LOOKUP_VLAN_MODE_SECURE);
> + } else {
> + qca8k_rmw(priv, QCA8K_PORT_LOOKUP_CTRL(port),
> + QCA8K_PORT_LOOKUP_VLAN_MODE,
> + QCA8K_PORT_LOOKUP_VLAN_MODE_NONE);
> + }
> +
> + return 0;
> +}
> +
> +static int
> +qca8k_port_vlan_prepare(struct dsa_switch *ds, int port,
> + const struct switchdev_obj_port_vlan *vlan)
> +{
> + return 0;
> +}
> +
> +static void
> +qca8k_port_vlan_add(struct dsa_switch *ds, int port,
> + const struct switchdev_obj_port_vlan *vlan)
> +{
> + struct qca8k_priv *priv = ds->priv;

Reverse Christmas notation please.

> + bool untagged = vlan->flags & BRIDGE_VLAN_INFO_UNTAGGED;
> + bool pvid = vlan->flags & BRIDGE_VLAN_INFO_PVID;
> + u16 vid;
> + int ret = 0;

here too.

> +
> + for (vid = vlan->vid_begin; vid <= vlan->vid_end && !ret; ++vid)
> + ret = qca8k_vlan_add(priv, port, vid, !untagged);
> +
> + if (ret)
> + dev_err(priv->dev, "Failed to add VLAN to port %d (%d)", port, ret);
> +

If for some reason there is a temporary failure in qca8k_vlan_add, you'd
be swallowing it instead of printing the error and stopping the
execution.

> + if (pvid) {
> + int shift = 16 * (port % 2);
> +
> + qca8k_rmw(priv, QCA8K_EGRESS_VLAN(port),

What's up with this name? Why not "ROUTER_DEFAULT_VID" which is how the
hardware calls it? I had some trouble finding it.

> + 0xffff << shift,
> + vlan->vid_end << shift);
> + qca8k_write(priv, QCA8K_REG_PORT_VLAN_CTRL0(port),
> + QCA8K_PORT_VLAN_CVID(vlan->vid_end) |
> + QCA8K_PORT_VLAN_SVID(vlan->vid_end));
> + }
> +}
> +
> +static int
> +qca8k_port_vlan_del(struct dsa_switch *ds, int port,
> + const struct switchdev_obj_port_vlan *vlan)
> +{
> + struct qca8k_priv *priv = ds->priv;
> + u16 vid;
> + int ret = 0;

Reverse Christmas notation please.

> +
> + for (vid = vlan->vid_begin; vid <= vlan->vid_end && !ret; ++vid)
> + ret = qca8k_vlan_del(priv, port, vid);
> +
> + if (ret)
> + dev_err(priv->dev, "Failed to delete VLAN from port %d (%d)", port, ret);

Same comment, could you move the "if" inside the "for"?

> +
> + return ret;
> +}
> +
> static enum dsa_tag_protocol
> qca8k_get_tag_protocol(struct dsa_switch *ds, int port,
> enum dsa_tag_protocol mp)
> @@ -1211,6 +1387,10 @@ static const struct dsa_switch_ops qca8k_switch_ops = {
> .port_fdb_add = qca8k_port_fdb_add,
> .port_fdb_del = qca8k_port_fdb_del,
> .port_fdb_dump = qca8k_port_fdb_dump,
> + .port_vlan_filtering = qca8k_port_vlan_filtering,
> + .port_vlan_prepare = qca8k_port_vlan_prepare,
> + .port_vlan_add = qca8k_port_vlan_add,
> + .port_vlan_del = qca8k_port_vlan_del,
> .phylink_validate = qca8k_phylink_validate,
> .phylink_mac_link_state = qca8k_phylink_mac_link_state,
> .phylink_mac_config = qca8k_phylink_mac_config,
> @@ -1261,6 +1441,7 @@ qca8k_sw_probe(struct mdio_device *mdiodev)
>
> priv->ds->dev = &mdiodev->dev;
> priv->ds->num_ports = QCA8K_NUM_PORTS;
> + priv->ds->configure_vlan_while_not_filtering = true;

Nice that you've enabled this. Thanks.

> priv->ds->priv = priv;
> priv->ops = qca8k_switch_ops;
> priv->ds->ops = &priv->ops;
> diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
> index 31439396401c..4e96275cbc3e 100644
> --- a/drivers/net/dsa/qca8k.h
> +++ b/drivers/net/dsa/qca8k.h
> @@ -22,6 +22,8 @@
>
> #define QCA8K_CPU_PORT 0
>
> +#define QCA8K_PORT_VID_DEF 1
> +
> /* Global control registers */
> #define QCA8K_REG_MASK_CTRL 0x000
> #define QCA8K_MASK_CTRL_ID_M 0xff
> @@ -126,6 +128,18 @@
> #define QCA8K_ATU_FUNC_FULL BIT(12)
> #define QCA8K_ATU_FUNC_PORT_M 0xf
> #define QCA8K_ATU_FUNC_PORT_S 8
> +#define QCA8K_REG_VTU_FUNC0 0x610
> +#define QCA8K_VTU_FUNC0_VALID BIT(20)
> +#define QCA8K_VTU_FUNC0_IVL_EN BIT(19)
> +#define QCA8K_VTU_FUNC0_EG_MODE_S(_i) (4 + (_i) * 2)
> +#define QCA8K_VTU_FUNC0_EG_MODE_UNMOD 0
> +#define QCA8K_VTU_FUNC0_EG_MODE_UNTAG 1
> +#define QCA8K_VTU_FUNC0_EG_MODE_TAG 2
> +#define QCA8K_VTU_FUNC0_EG_MODE_NOT 3
> +#define QCA8K_REG_VTU_FUNC1 0x614
> +#define QCA8K_VTU_FUNC1_BUSY BIT(31)
> +#define QCA8K_VTU_FUNC1_VID_S 16
> +#define QCA8K_VTU_FUNC1_FULL BIT(4)
> #define QCA8K_REG_GLOBAL_FW_CTRL0 0x620
> #define QCA8K_GLOBAL_FW_CTRL0_CPU_PORT_EN BIT(10)
> #define QCA8K_REG_GLOBAL_FW_CTRL1 0x624
> @@ -135,6 +149,11 @@
> #define QCA8K_GLOBAL_FW_CTRL1_UC_DP_S 0
> #define QCA8K_PORT_LOOKUP_CTRL(_i) (0x660 + (_i) * 0xc)
> #define QCA8K_PORT_LOOKUP_MEMBER GENMASK(6, 0)
> +#define QCA8K_PORT_LOOKUP_VLAN_MODE GENMASK(9, 8)
> +#define QCA8K_PORT_LOOKUP_VLAN_MODE_NONE (0 << 8)
> +#define QCA8K_PORT_LOOKUP_VLAN_MODE_FALLBACK (1 << 8)
> +#define QCA8K_PORT_LOOKUP_VLAN_MODE_CHECK (2 << 8)
> +#define QCA8K_PORT_LOOKUP_VLAN_MODE_SECURE (3 << 8)
> #define QCA8K_PORT_LOOKUP_STATE_MASK GENMASK(18, 16)
> #define QCA8K_PORT_LOOKUP_STATE_DISABLED (0 << 16)
> #define QCA8K_PORT_LOOKUP_STATE_BLOCKING (1 << 16)
> @@ -178,6 +197,15 @@ enum qca8k_fdb_cmd {
> QCA8K_FDB_SEARCH = 7,
> };
>
> +enum qca8k_vlan_cmd {
> + QCA8K_VLAN_FLUSH = 1,
> + QCA8K_VLAN_LOAD = 2,
> + QCA8K_VLAN_PURGE = 3,
> + QCA8K_VLAN_REMOVE_PORT = 4,
> + QCA8K_VLAN_NEXT = 5,
> + QCA8K_VLAN_READ = 6,
> +};
> +
> struct ar8xxx_port_status {
> int enabled;
> };
> --
> 2.20.1

Thanks,
-Vladimir