| Message ID | 20210415092610.953134-5-tobias@waldekranz.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: dsa: Allow default tag protocol to be overridden from DT | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for net-next |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | success | CCed 7 of 7 maintainers |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 7 this patch: 7 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 154 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 7 this patch: 7 |
| netdev/header_inline | success | Link |
On Thu, Apr 15, 2021 at 11:26:09AM +0200, Tobias Waldekranz wrote: > Some combinations of tag protocols and Ethernet controllers are > incompatible, and it is hard for the driver to keep track of these. > > Therefore, allow the device tree author (typically the board vendor) > to inform the driver of this fact by selecting an alternate protocol > that is known to work. > > Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com> > --- > include/net/dsa.h | 5 +++ > net/dsa/dsa2.c | 95 ++++++++++++++++++++++++++++++++++++++--------- > 2 files changed, 83 insertions(+), 17 deletions(-) > > diff --git a/include/net/dsa.h b/include/net/dsa.h > index 1259b0f40684..2b25fe1ad5b7 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 d7c22e3a1fbf..80dbf8b6bf8f 100644 > --- a/net/dsa/dsa2.c > +++ b/net/dsa/dsa2.c > @@ -668,6 +668,35 @@ 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; > + > + if (!ds->ops->change_tag_protocol) { > + dev_err(ds->dev, "Tag protocol cannot be modified\n"); > + return -EINVAL; > + } We validated this already here: if (ds->ops->change_tag_protocol) { tag_ops = dsa_find_tagger_by_name(user_protocol); } else { dev_err(ds->dev, "Tag protocol cannot be modified\n"); return -EINVAL; } > + > + 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, "Tag protocol \"%s\" is not supported\n", > + tag_ops->name); Maybe instead of saying "is not supported", you can say "Changing the tag protocol to \"%s\" returned %pe", tag_ops->name, ERR_PTR(err) which is a bit more informative. > + return err; > + } > + } > + > + return 0; > +} > + > static int dsa_switch_setup(struct dsa_switch *ds) > { > struct dsa_devlink_priv *dl_priv; > @@ -718,6 +747,10 @@ 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 +1101,60 @@ 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) { > + tag_ops = dsa_find_tagger_by_name(user_protocol); > + } else { > + dev_err(ds->dev, "Tag protocol cannot be modified\n"); > + return -EINVAL; > + } Your choice, but how about: 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; So at the end of dsa_port_parse_cpu, we have a dst->tag_ops which is temporarily out of sync with the driver. We call dsa_port_set_tag_protocol() with the new tagging protocol _before_ we call ds->ops->change_tag_protocol. But as opposed to dsa_switch_change_tag_proto(), if ds->ops->change_tag_protocol fails from the probe path, we treat it as a catastrophic error. So at the end there is no risk of having anything out of sync I believe. Maybe you should write this down in a comment? The logic is pretty convoluted and hard to follow. > } > > @@ -1117,12 +1176,14 @@ 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 +1295,7 @@ 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")) > -- > 2.25.1 >
diff --git a/include/net/dsa.h b/include/net/dsa.h index 1259b0f40684..2b25fe1ad5b7 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 d7c22e3a1fbf..80dbf8b6bf8f 100644 --- a/net/dsa/dsa2.c +++ b/net/dsa/dsa2.c @@ -668,6 +668,35 @@ 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; + + if (!ds->ops->change_tag_protocol) { + dev_err(ds->dev, "Tag protocol cannot be modified\n"); + return -EINVAL; + } + + 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, "Tag protocol \"%s\" is not supported\n", + tag_ops->name); + return err; + } + } + + return 0; +} + static int dsa_switch_setup(struct dsa_switch *ds) { struct dsa_devlink_priv *dl_priv; @@ -718,6 +747,10 @@ 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 +1101,60 @@ 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) { + tag_ops = dsa_find_tagger_by_name(user_protocol); + } else { + dev_err(ds->dev, "Tag protocol cannot be modified\n"); + return -EINVAL; + } + } 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; } @@ -1117,12 +1176,14 @@ 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 +1295,7 @@ 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"))
Some combinations of tag protocols and Ethernet controllers are incompatible, and it is hard for the driver to keep track of these. Therefore, allow the device tree author (typically the board vendor) to inform the driver of this fact by selecting an alternate protocol that is known to work. Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com> --- include/net/dsa.h | 5 +++ net/dsa/dsa2.c | 95 ++++++++++++++++++++++++++++++++++++++--------- 2 files changed, 83 insertions(+), 17 deletions(-)