net: dsa: report and change port dscp priority using dcbnl

Similar to the port-based default priority, IEEE 802.1Q-2018 allows the
Application Priority Table to define QoS classes (0 to 7) per IP DSCP
value (0 to 63).

In the absence of an app table entry for a packet with DSCP value X,
QoS classification for that packet falls back to other methods (VLAN PCP
or port-based default). The presence of an app table for DSCP value X
with priority Y makes the hardware classify the packet to QoS class Y.

As opposed to the default-prio where DSA exposes only a "set" in
dsa_switch_ops (because the port-based default is the fallback, it
always exists, either implicitly or explicitly), for DSCP priorities we
expose an "add" and a "del". The addition of a DSCP entry means trusting
that DSCP priority, the deletion means ignoring it.

Drivers that already trust (at least some) DSCP values can describe
their configuration in dsa_switch_ops :: port_get_dscp_prio(), which is
called for each DSCP value from 0 to 63.

Again, there can be more than one dcbnl app table entry for the same
DSCP value, DSA chooses the one with the largest configured priority.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 1220af73151b1a7c40d147e3f61fbfb707c96534..9bfe984fcdbfc5c55efbab5acea006d41c5ebe60 100644 (file)
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -898,6 +898,11 @@ struct dsa_switch_ops {
        int     (*port_get_default_prio)(struct dsa_switch *ds, int port);
        int     (*port_set_default_prio)(struct dsa_switch *ds, int port,
                                         u8 prio);
+       int     (*port_get_dscp_prio)(struct dsa_switch *ds, int port, u8 dscp);
+       int     (*port_add_dscp_prio)(struct dsa_switch *ds, int port, u8 dscp,
+                                     u8 prio);
+       int     (*port_del_dscp_prio)(struct dsa_switch *ds, int port, u8 dscp,
+                                     u8 prio);
 
        /*
         * Suspend and resume

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 97f5da81fe687c4424b3c764e376f2f5a07a6ceb..f9cecda791d559443196c3b49c4ca28f1e0934bf 100644 (file)
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -1880,6 +1880,40 @@ dsa_slave_dcbnl_set_default_prio(struct net_device *dev, struct dcb_app *app)
        return 0;
 }
 
+static int __maybe_unused
+dsa_slave_dcbnl_add_dscp_prio(struct net_device *dev, struct dcb_app *app)
+{
+       struct dsa_port *dp = dsa_slave_to_port(dev);
+       struct dsa_switch *ds = dp->ds;
+       unsigned long mask, new_prio;
+       int err, port = dp->index;
+       u8 dscp = app->protocol;
+
+       if (!ds->ops->port_add_dscp_prio)
+               return -EOPNOTSUPP;
+
+       if (dscp >= 64) {
+               netdev_err(dev, "DSCP APP entry with protocol value %u is invalid\n",
+                          dscp);
+               return -EINVAL;
+       }
+
+       err = dcb_ieee_setapp(dev, app);
+       if (err)
+               return err;
+
+       mask = dcb_ieee_getapp_mask(dev, app);
+       new_prio = __fls(mask);
+
+       err = ds->ops->port_add_dscp_prio(ds, port, dscp, new_prio);
+       if (err) {
+               dcb_ieee_delapp(dev, app);
+               return err;
+       }
+
+       return 0;
+}
+
 static int __maybe_unused dsa_slave_dcbnl_ieee_setapp(struct net_device *dev,
                                                      struct dcb_app *app)
 {
@@ -1892,6 +1926,8 @@ static int __maybe_unused dsa_slave_dcbnl_ieee_setapp(struct net_device *dev,
                        return -EOPNOTSUPP;
                }
                break;
+       case IEEE_8021QAZ_APP_SEL_DSCP:
+               return dsa_slave_dcbnl_add_dscp_prio(dev, app);
        default:
                return -EOPNOTSUPP;
        }
@@ -1924,6 +1960,30 @@ dsa_slave_dcbnl_del_default_prio(struct net_device *dev, struct dcb_app *app)
        return 0;
 }
 
+static int __maybe_unused
+dsa_slave_dcbnl_del_dscp_prio(struct net_device *dev, struct dcb_app *app)
+{
+       struct dsa_port *dp = dsa_slave_to_port(dev);
+       struct dsa_switch *ds = dp->ds;
+       int err, port = dp->index;
+       u8 dscp = app->protocol;
+
+       if (!ds->ops->port_del_dscp_prio)
+               return -EOPNOTSUPP;
+
+       err = dcb_ieee_delapp(dev, app);
+       if (err)
+               return err;
+
+       err = ds->ops->port_del_dscp_prio(ds, port, dscp, app->priority);
+       if (err) {
+               dcb_ieee_setapp(dev, app);
+               return err;
+       }
+
+       return 0;
+}
+
 static int __maybe_unused dsa_slave_dcbnl_ieee_delapp(struct net_device *dev,
                                                      struct dcb_app *app)
 {
@@ -1936,6 +1996,8 @@ static int __maybe_unused dsa_slave_dcbnl_ieee_delapp(struct net_device *dev,
                        return -EOPNOTSUPP;
                }
                break;
+       case IEEE_8021QAZ_APP_SEL_DSCP:
+               return dsa_slave_dcbnl_del_dscp_prio(dev, app);
        default:
                return -EOPNOTSUPP;
        }
@@ -1967,6 +2029,30 @@ static int dsa_slave_dcbnl_init(struct net_device *dev)
                        return err;
        }
 
+       if (ds->ops->port_get_dscp_prio) {
+               int protocol;
+
+               for (protocol = 0; protocol < 64; protocol++) {
+                       struct dcb_app app = {
+                               .selector = IEEE_8021QAZ_APP_SEL_DSCP,
+                               .protocol = protocol,
+                       };
+                       int prio;
+
+                       prio = ds->ops->port_get_dscp_prio(ds, port, protocol);
+                       if (prio == -EOPNOTSUPP)
+                               continue;
+                       if (prio < 0)
+                               return prio;
+
+                       app.priority = prio;
+
+                       err = dcb_ieee_setapp(dev, &app);
+                       if (err)
+                               return err;
+               }
+       }
+
        return 0;
 }