diff --git a/include/net/dsa.h b/include/net/dsa.h
index b52e9b057be407478c95823562548b9deef0d60b..507082959aa4f055cecc0636f2a30c641d90a820 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -149,6 +149,11 @@ struct dsa_switch_tree {
/* Tagging protocol operations */
const struct dsa_device_ops *tag_ops;
+ /* Default tagging protocol preferred by the switches in this
+ * tree.
+ */
+ enum dsa_tag_protocol default_proto;
+
/*
* Configuration data for the platform device that owns
* this dsa switch tree instance.
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index d7c22e3a1fbfc6708523cc54997790a1700a56ef..b71e87909f0e3987281ddfe5305b0a72fb71cdaf 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -668,6 +668,30 @@ static const struct devlink_ops dsa_devlink_ops = {
.sb_occ_tc_port_bind_get = dsa_devlink_sb_occ_tc_port_bind_get,
};
+static int dsa_switch_setup_tag_protocol(struct dsa_switch *ds)
+{
+ const struct dsa_device_ops *tag_ops = ds->dst->tag_ops;
+ struct dsa_switch_tree *dst = ds->dst;
+ int port, err;
+
+ if (tag_ops->proto == dst->default_proto)
+ return 0;
+
+ for (port = 0; port < ds->num_ports; port++) {
+ if (!dsa_is_cpu_port(ds, port))
+ continue;
+
+ err = ds->ops->change_tag_protocol(ds, port, tag_ops->proto);
+ if (err) {
+ dev_err(ds->dev, "Unable to use tag protocol \"%s\": %pe\n",
+ tag_ops->name, ERR_PTR(err));
+ return err;
+ }
+ }
+
+ return 0;
+}
+
static int dsa_switch_setup(struct dsa_switch *ds)
{
struct dsa_devlink_priv *dl_priv;
@@ -718,6 +742,10 @@ static int dsa_switch_setup(struct dsa_switch *ds)
if (err < 0)
goto unregister_notifier;
+ err = dsa_switch_setup_tag_protocol(ds);
+ if (err)
+ goto teardown;
+
devlink_params_publish(ds->devlink);
if (!ds->slave_mii_bus && ds->ops->phy_read) {
@@ -1068,34 +1096,60 @@ static enum dsa_tag_protocol dsa_get_tag_protocol(struct dsa_port *dp,
return ds->ops->get_tag_protocol(ds, dp->index, tag_protocol);
}
-static int dsa_port_parse_cpu(struct dsa_port *dp, struct net_device *master)
+static int dsa_port_parse_cpu(struct dsa_port *dp, struct net_device *master,
+ const char *user_protocol)
{
struct dsa_switch *ds = dp->ds;
struct dsa_switch_tree *dst = ds->dst;
const struct dsa_device_ops *tag_ops;
- enum dsa_tag_protocol tag_protocol;
+ enum dsa_tag_protocol default_proto;
+
+ /* Find out which protocol the switch would prefer. */
+ default_proto = dsa_get_tag_protocol(dp, master);
+ if (dst->default_proto) {
+ if (dst->default_proto != default_proto) {
+ dev_err(ds->dev,
+ "A DSA switch tree can have only one tagging protocol\n");
+ return -EINVAL;
+ }
+ } else {
+ dst->default_proto = default_proto;
+ }
+
+ /* See if the user wants to override that preference. */
+ if (user_protocol) {
+ if (!ds->ops->change_tag_protocol) {
+ dev_err(ds->dev, "Tag protocol cannot be modified\n");
+ return -EINVAL;
+ }
+
+ tag_ops = dsa_find_tagger_by_name(user_protocol);
+ } else {
+ tag_ops = dsa_tag_driver_get(default_proto);
+ }
+
+ if (IS_ERR(tag_ops)) {
+ if (PTR_ERR(tag_ops) == -ENOPROTOOPT)
+ return -EPROBE_DEFER;
+
+ dev_warn(ds->dev, "No tagger for this switch\n");
+ return PTR_ERR(tag_ops);
+ }
- tag_protocol = dsa_get_tag_protocol(dp, master);
if (dst->tag_ops) {
- if (dst->tag_ops->proto != tag_protocol) {
+ if (dst->tag_ops != tag_ops) {
dev_err(ds->dev,
"A DSA switch tree can have only one tagging protocol\n");
+
+ dsa_tag_driver_put(tag_ops);
return -EINVAL;
}
+
/* In the case of multiple CPU ports per switch, the tagging
- * protocol is still reference-counted only per switch tree, so
- * nothing to do here.
+ * protocol is still reference-counted only per switch tree.
*/
+ dsa_tag_driver_put(tag_ops);
} else {
- tag_ops = dsa_tag_driver_get(tag_protocol);
- if (IS_ERR(tag_ops)) {
- if (PTR_ERR(tag_ops) == -ENOPROTOOPT)
- return -EPROBE_DEFER;
- dev_warn(ds->dev, "No tagger for this switch\n");
- dp->master = NULL;
- return PTR_ERR(tag_ops);
- }
-
dst->tag_ops = tag_ops;
}
@@ -1104,6 +1158,19 @@ static int dsa_port_parse_cpu(struct dsa_port *dp, struct net_device *master)
dsa_port_set_tag_protocol(dp, dst->tag_ops);
dp->dst = dst;
+ /* At this point, the tree may be configured to use a different
+ * tagger than the one chosen by the switch driver during
+ * .setup, in the case when a user selects a custom protocol
+ * through the DT.
+ *
+ * This is resolved by syncing the driver with the tree in
+ * dsa_switch_setup_tag_protocol once .setup has run and the
+ * driver is ready to accept calls to .change_tag_protocol. If
+ * the driver does not support the custom protocol at that
+ * point, the tree is wholly rejected, thereby ensuring that the
+ * tree and driver are always in agreement on the protocol to
+ * use.
+ */
return 0;
}
@@ -1117,12 +1184,14 @@ static int dsa_port_parse_of(struct dsa_port *dp, struct device_node *dn)
if (ethernet) {
struct net_device *master;
+ const char *user_protocol;
master = of_find_net_device_by_node(ethernet);
if (!master)
return -EPROBE_DEFER;
- return dsa_port_parse_cpu(dp, master);
+ user_protocol = of_get_property(dn, "dsa-tag-protocol", NULL);
+ return dsa_port_parse_cpu(dp, master, user_protocol);
}
if (link)
@@ -1234,7 +1303,7 @@ static int dsa_port_parse(struct dsa_port *dp, const char *name,
dev_put(master);
- return dsa_port_parse_cpu(dp, master);
+ return dsa_port_parse_cpu(dp, master, NULL);
}
if (!strcmp(name, "dsa"))