net: dsa: tag_ocelot: create separate tagger for Seville

The ocelot tagger is a hot mess currently, it relies on memory
initialized by the attached driver for basic frame transmission.
This is against all that DSA tagging protocols stand for, which is that
the transmission and reception of a DSA-tagged frame, the data path,
should be independent from the switch control path, because the tag
protocol is in principle hot-pluggable and reusable across switches
(even if in practice it wasn't until very recently). But if another
driver like dsa_loop wants to make use of tag_ocelot, it couldn't.

This was done to have common code between Felix and Ocelot, which have
one bit difference in the frame header format. Quoting from commit
67c2404922c2 ("net: dsa: felix: create a template for the DSA tags on
xmit"):

    Other alternatives have been analyzed, such as:
    - Create a separate tag_seville.c: too much code duplication for just 1
      bit field difference.
    - Create a separate DSA_TAG_PROTO_SEVILLE under tag_ocelot.c, just like
      tag_brcm.c, which would have a separate .xmit function. Again, too
      much code duplication for just 1 bit field difference.
    - Allocate the template from the init function of the tag_ocelot.c
      module, instead of from the driver: couldn't figure out a method of
      accessing the correct port template corresponding to the correct
      tagger in the .xmit function.

The really interesting part is that Seville should have had its own
tagging protocol defined - it is not compatible on the wire with Ocelot,
even for that single bit. In principle, a packet generated by
DSA_TAG_PROTO_OCELOT when booted on NXP LS1028A would look in a certain
way, but when booted on NXP T1040 it would look differently. The reverse
is also true: a packet generated by a Seville switch would be
interpreted incorrectly by Wireshark if it was told it was generated by
an Ocelot switch.

Actually things are a bit more nuanced. If we concentrate only on the
DSA tag, what I said above is true, but Ocelot/Seville also support an
optional DSA tag prefix, which can be short or long, and it is possible
to distinguish the two taggers based on an integer constant put in that
prefix. Nonetheless, creating a separate tagger is still justified,
since the tag prefix is optional, and without it, there is again no way
to distinguish.

Claiming backwards binary compatibility is a bit more tough, since I've
already changed the format of tag_ocelot once, in commit 5124197ce58b
("net: dsa: tag_ocelot: use a short prefix on both ingress and egress").
Therefore I am not very concerned with treating this as a bugfix and
backporting it to stable kernels (which would be another mess due to the
fact that there would be lots of conflicts with the other DSA_TAG_PROTO*
definitions). It's just simpler to say that the string values of the
taggers have ABI value starting with kernel 5.12, which will be when the
changing of tag protocol via /sys/class/net/<dsa-master>/dsa/tagging
goes live.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c
index 60e0d354adea95d2c40181ce8fe5a36597af3a6f..7e1f6350139bd24eabc11f44f4ed9c49f4aacac5 100644 (file)
--- a/drivers/net/dsa/ocelot/felix.c
+++ b/drivers/net/dsa/ocelot/felix.c
@@ -431,6 +431,7 @@ static int felix_set_tag_protocol(struct dsa_switch *ds, int cpu,
        int err;
 
        switch (proto) {
+       case DSA_TAG_PROTO_SEVILLE:
        case DSA_TAG_PROTO_OCELOT:
                err = felix_setup_tag_npi(ds, cpu);
                break;
@@ -448,6 +449,7 @@ static void felix_del_tag_protocol(struct dsa_switch *ds, int cpu,
                                   enum dsa_tag_protocol proto)
 {
        switch (proto) {
+       case DSA_TAG_PROTO_SEVILLE:
        case DSA_TAG_PROTO_OCELOT:
                felix_teardown_tag_npi(ds, cpu);
                break;
@@ -471,7 +473,8 @@ static int felix_change_tag_protocol(struct dsa_switch *ds, int cpu,
        enum dsa_tag_protocol old_proto = felix->tag_proto;
        int err;
 
-       if (proto != DSA_TAG_PROTO_OCELOT &&
+       if (proto != DSA_TAG_PROTO_SEVILLE &&
+           proto != DSA_TAG_PROTO_OCELOT &&
            proto != DSA_TAG_PROTO_OCELOT_8021Q)
                return -EPROTONOSUPPORT;
 
@@ -1003,7 +1006,6 @@ static int felix_init_structs(struct felix *felix, int num_phys_ports)
        for (port = 0; port < num_phys_ports; port++) {
                struct ocelot_port *ocelot_port;
                struct regmap *target;
-               u8 *template;
 
                ocelot_port = devm_kzalloc(ocelot->dev,
                                           sizeof(struct ocelot_port),
@@ -1029,22 +1031,10 @@ static int felix_init_structs(struct felix *felix, int num_phys_ports)
                        return PTR_ERR(target);
                }
 
-               template = devm_kzalloc(ocelot->dev, OCELOT_TOTAL_TAG_LEN,
-                                       GFP_KERNEL);
-               if (!template) {
-                       dev_err(ocelot->dev,
-                               "Failed to allocate memory for DSA tag\n");
-                       kfree(port_phy_modes);
-                       return -ENOMEM;
-               }
-
                ocelot_port->phy_mode = port_phy_modes[port];
                ocelot_port->ocelot = ocelot;
                ocelot_port->target = target;
-               ocelot_port->xmit_template = template;
                ocelot->ports[port] = ocelot_port;
-
-               felix->info->xmit_template_populate(ocelot, port);
        }
 
        kfree(port_phy_modes);

diff --git a/drivers/net/dsa/ocelot/felix.h b/drivers/net/dsa/ocelot/felix.h
index 9d4459f2fffb84481a662401e69f0ef5c5c5287c..b2ea425c5803b9935c13d85d93fba304edf3b1e4 100644 (file)
--- a/drivers/net/dsa/ocelot/felix.h
+++ b/drivers/net/dsa/ocelot/felix.h
@@ -34,7 +34,6 @@ struct felix_info {
                                 enum tc_setup_type type, void *type_data);
        void    (*port_sched_speed_set)(struct ocelot *ocelot, int port,
                                        u32 speed);
-       void    (*xmit_template_populate)(struct ocelot *ocelot, int port);
 };
 
 extern const struct dsa_switch_ops felix_switch_ops;

diff --git a/drivers/net/dsa/ocelot/felix_vsc9959.c b/drivers/net/dsa/ocelot/felix_vsc9959.c
index cacc6f9c01135cd9763fa2db3e69f6c83935db9a..32b885fcaf900a76d5c62cce532abb3b21ff2d9b 100644 (file)
--- a/drivers/net/dsa/ocelot/felix_vsc9959.c
+++ b/drivers/net/dsa/ocelot/felix_vsc9959.c
@@ -1339,31 +1339,6 @@ static int vsc9959_port_setup_tc(struct dsa_switch *ds, int port,
        }
 }
 
-static void vsc9959_xmit_template_populate(struct ocelot *ocelot, int port)
-{
-       struct ocelot_port *ocelot_port = ocelot->ports[port];
-       u8 *template = ocelot_port->xmit_template;
-       u64 bypass, dest, src;
-       __be32 *prefix;
-       u8 *injection;
-
-       /* Set the source port as the CPU port module and not the
-        * NPI port
-        */
-       src = ocelot->num_phys_ports;
-       dest = BIT(port);
-       bypass = true;
-
-       injection = template + OCELOT_SHORT_PREFIX_LEN;
-       prefix = (__be32 *)template;
-
-       packing(injection, &bypass, 127, 127, OCELOT_TAG_LEN, PACK, 0);
-       packing(injection, &dest,    68,  56, OCELOT_TAG_LEN, PACK, 0);
-       packing(injection, &src,     46,  43, OCELOT_TAG_LEN, PACK, 0);
-
-       *prefix = cpu_to_be32(0x8880000a);
-}
-
 static const struct felix_info felix_info_vsc9959 = {
        .target_io_res          = vsc9959_target_io_res,
        .port_io_res            = vsc9959_port_io_res,
@@ -1386,7 +1361,6 @@ static const struct felix_info felix_info_vsc9959 = {
        .prevalidate_phy_mode   = vsc9959_prevalidate_phy_mode,
        .port_setup_tc          = vsc9959_port_setup_tc,
        .port_sched_speed_set   = vsc9959_sched_speed_set,
-       .xmit_template_populate = vsc9959_xmit_template_populate,
 };
 
 static irqreturn_t felix_irq_handler(int irq, void *data)

diff --git a/drivers/net/dsa/ocelot/seville_vsc9953.c b/drivers/net/dsa/ocelot/seville_vsc9953.c
index d7348ea4831e7720c96214a9f2018f75695e93d2..84f93a874d502a185885733b5ca4aa3c1c2c71ec 100644 (file)
--- a/drivers/net/dsa/ocelot/seville_vsc9953.c
+++ b/drivers/net/dsa/ocelot/seville_vsc9953.c
@@ -1165,31 +1165,6 @@ static void vsc9953_mdio_bus_free(struct ocelot *ocelot)
        mdiobus_unregister(felix->imdio);
 }
 
-static void vsc9953_xmit_template_populate(struct ocelot *ocelot, int port)
-{
-       struct ocelot_port *ocelot_port = ocelot->ports[port];
-       u8 *template = ocelot_port->xmit_template;
-       u64 bypass, dest, src;
-       __be32 *prefix;
-       u8 *injection;
-
-       /* Set the source port as the CPU port module and not the
-        * NPI port
-        */
-       src = ocelot->num_phys_ports;
-       dest = BIT(port);
-       bypass = true;
-
-       injection = template + OCELOT_SHORT_PREFIX_LEN;
-       prefix = (__be32 *)template;
-
-       packing(injection, &bypass, 127, 127, OCELOT_TAG_LEN, PACK, 0);
-       packing(injection, &dest,    67,  57, OCELOT_TAG_LEN, PACK, 0);
-       packing(injection, &src,     46,  43, OCELOT_TAG_LEN, PACK, 0);
-
-       *prefix = cpu_to_be32(0x88800005);
-}
-
 static const struct felix_info seville_info_vsc9953 = {
        .target_io_res          = vsc9953_target_io_res,
        .port_io_res            = vsc9953_port_io_res,
@@ -1206,7 +1181,6 @@ static const struct felix_info seville_info_vsc9953 = {
        .mdio_bus_free          = vsc9953_mdio_bus_free,
        .phylink_validate       = vsc9953_phylink_validate,
        .prevalidate_phy_mode   = vsc9953_prevalidate_phy_mode,
-       .xmit_template_populate = vsc9953_xmit_template_populate,
 };
 
 static int seville_probe(struct platform_device *pdev)
@@ -1246,7 +1220,7 @@ static int seville_probe(struct platform_device *pdev)
        ds->ops = &felix_switch_ops;
        ds->priv = ocelot;
        felix->ds = ds;
-       felix->tag_proto = DSA_TAG_PROTO_OCELOT;
+       felix->tag_proto = DSA_TAG_PROTO_SEVILLE;
 
        err = dsa_register_switch(ds);
        if (err) {

diff --git a/include/linux/dsa/ocelot.h b/include/linux/dsa/ocelot.h
index 763dbbfaff7a9c60c2192fa8218ce05d7630aa22..c6bc45ae5e03a4116c49ee22d91081288257111f 100644 (file)
--- a/include/linux/dsa/ocelot.h
+++ b/include/linux/dsa/ocelot.h
@@ -195,6 +195,16 @@ static inline void ocelot_ifh_set_qos_class(void *injection, u64 qos_class)
        packing(injection, &qos_class, 19, 17, OCELOT_TAG_LEN, PACK, 0);
 }
 
+static inline void seville_ifh_set_dest(void *injection, u64 dest)
+{
+       packing(injection, &dest, 67, 57, OCELOT_TAG_LEN, PACK, 0);
+}
+
+static inline void ocelot_ifh_set_src(void *injection, u64 src)
+{
+       packing(injection, &src, 46, 43, OCELOT_TAG_LEN, PACK, 0);
+}
+
 static inline void ocelot_ifh_set_tag_type(void *injection, u64 tag_type)
 {
        packing(injection, &tag_type, 16, 16, OCELOT_TAG_LEN, PACK, 0);

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 74457aaffec776de364cca6f3cc285ebbd2bc35d..b095ef114fe8702cfcc2ce9417e83c9fd1bc66d0 100644 (file)
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -48,6 +48,7 @@ struct phylink_link_state;
 #define DSA_TAG_PROTO_HELLCREEK_VALUE          18
 #define DSA_TAG_PROTO_XRS700X_VALUE            19
 #define DSA_TAG_PROTO_OCELOT_8021Q_VALUE       20
+#define DSA_TAG_PROTO_SEVILLE_VALUE            21
 
 enum dsa_tag_protocol {
        DSA_TAG_PROTO_NONE              = DSA_TAG_PROTO_NONE_VALUE,
@@ -71,6 +72,7 @@ enum dsa_tag_protocol {
        DSA_TAG_PROTO_HELLCREEK         = DSA_TAG_PROTO_HELLCREEK_VALUE,
        DSA_TAG_PROTO_XRS700X           = DSA_TAG_PROTO_XRS700X_VALUE,
        DSA_TAG_PROTO_OCELOT_8021Q      = DSA_TAG_PROTO_OCELOT_8021Q_VALUE,
+       DSA_TAG_PROTO_SEVILLE           = DSA_TAG_PROTO_SEVILLE_VALUE,
 };
 
 struct packet_type;

diff --git a/net/dsa/tag_ocelot.c b/net/dsa/tag_ocelot.c
index fe00519229d7b484e0b8929bdeee70ea7ec3cac2..a7dd61c8e005137dcb2e921fb140202291b7dc7d 100644 (file)
--- a/net/dsa/tag_ocelot.c
+++ b/net/dsa/tag_ocelot.c
@@ -24,33 +24,52 @@ static void ocelot_xmit_ptp(struct dsa_port *dp, void *injection,
        ocelot_ifh_set_rew_op(injection, rew_op);
 }
 
-static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
-                                  struct net_device *netdev)
+static void ocelot_xmit_common(struct sk_buff *skb, struct net_device *netdev,
+                              __be32 ifh_prefix, void **ifh)
 {
        struct dsa_port *dp = dsa_slave_to_port(netdev);
        struct sk_buff *clone = DSA_SKB_CB(skb)->clone;
        struct dsa_switch *ds = dp->ds;
-       struct ocelot *ocelot = ds->priv;
-       struct ocelot_port *ocelot_port;
-       u8 *prefix, *injection;
-
-       ocelot_port = ocelot->ports[dp->index];
+       void *injection;
+       __be32 *prefix;
 
        injection = skb_push(skb, OCELOT_TAG_LEN);
-
        prefix = skb_push(skb, OCELOT_SHORT_PREFIX_LEN);
 
-       memcpy(prefix, ocelot_port->xmit_template, OCELOT_TOTAL_TAG_LEN);
-
-       /* Fix up the fields which are not statically determined
-        * in the template
-        */
+       *prefix = ifh_prefix;
+       memset(injection, 0, OCELOT_TAG_LEN);
+       ocelot_ifh_set_bypass(injection, 1);
+       ocelot_ifh_set_src(injection, ds->num_ports);
        ocelot_ifh_set_qos_class(injection, skb->priority);
 
        /* TX timestamping was requested */
        if (clone)
                ocelot_xmit_ptp(dp, injection, clone);
 
+       *ifh = injection;
+}
+
+static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
+                                  struct net_device *netdev)
+{
+       struct dsa_port *dp = dsa_slave_to_port(netdev);
+       void *injection;
+
+       ocelot_xmit_common(skb, netdev, cpu_to_be32(0x8880000a), &injection);
+       ocelot_ifh_set_dest(injection, BIT(dp->index));
+
+       return skb;
+}
+
+static struct sk_buff *seville_xmit(struct sk_buff *skb,
+                                   struct net_device *netdev)
+{
+       struct dsa_port *dp = dsa_slave_to_port(netdev);
+       void *injection;
+
+       ocelot_xmit_common(skb, netdev, cpu_to_be32(0x88800005), &injection);
+       seville_ifh_set_dest(injection, BIT(dp->index));
+
        return skb;
 }
 
@@ -147,7 +166,26 @@ static const struct dsa_device_ops ocelot_netdev_ops = {
        .promisc_on_master      = true,
 };
 
-MODULE_LICENSE("GPL v2");
+DSA_TAG_DRIVER(ocelot_netdev_ops);
 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_OCELOT);
 
-module_dsa_tag_driver(ocelot_netdev_ops);
+static const struct dsa_device_ops seville_netdev_ops = {
+       .name                   = "seville",
+       .proto                  = DSA_TAG_PROTO_SEVILLE,
+       .xmit                   = seville_xmit,
+       .rcv                    = ocelot_rcv,
+       .overhead               = OCELOT_TOTAL_TAG_LEN,
+       .promisc_on_master      = true,
+};
+
+DSA_TAG_DRIVER(seville_netdev_ops);
+MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_SEVILLE);
+
+static struct dsa_tag_driver *ocelot_tag_driver_array[] = {
+       &DSA_TAG_DRIVER_NAME(ocelot_netdev_ops),
+       &DSA_TAG_DRIVER_NAME(seville_netdev_ops),
+};
+
+module_dsa_tag_drivers(ocelot_tag_driver_array);
+
+MODULE_LICENSE("GPL v2");