net: mscc: ocelot: don't hardcode the number of the CPU port

VSC7514 is a 10-port switch with 2 extra "CPU ports" (targets in the
queuing subsystem for terminating traffic locally).

There are 2 issues with hardcoding the CPU port as #10:
- It is not clear which snippets of the code are configuring something
  for one of the CPU ports, and which snippets are just doing something
  related to the number of physical ports.
- Actually any physical port can act as a CPU port connected to an
  external CPU (in addition to the local CPU). This is called NPI mode
  (Node Processor Interface) and is the way that the 6-port VSC9959
  (Felix) switch is integrated inside NXP LS1028A (the "local management
  CPU" functionality is not used there).

This patch makes it clear that the ocelot_bridge_stp_state_set function
operates on the CPU port (by making it an implicit member of the
bridging domain), and at the same time adds logic for the NPI port (aka
a physical port) to play the role of a CPU port (it shouldn't be part of
bridge_fwd_mask, as it's not explicitly enslaved to a bridge).

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

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index bba6d60..3e7a279 100644 (file)
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1383,7 +1383,7 @@ static void ocelot_bridge_stp_state_set(struct ocelot *ocelot, int port,
         * a source for the other ports.
         */
        for (p = 0; p < ocelot->num_phys_ports; p++) {
-               if (ocelot->bridge_fwd_mask & BIT(p)) {
+               if (p == ocelot->cpu || (ocelot->bridge_fwd_mask & BIT(p))) {
                        unsigned long mask = ocelot->bridge_fwd_mask & ~BIT(p);
 
                        for (i = 0; i < ocelot->num_phys_ports; i++) {
@@ -1398,15 +1398,18 @@ static void ocelot_bridge_stp_state_set(struct ocelot *ocelot, int port,
                                }
                        }
 
-                       ocelot_write_rix(ocelot,
-                                        BIT(ocelot->num_phys_ports) | mask,
+                       /* Avoid the NPI port from looping back to itself */
+                       if (p != ocelot->cpu)
+                               mask |= BIT(ocelot->cpu);
+
+                       ocelot_write_rix(ocelot, mask,
                                         ANA_PGID_PGID, PGID_SRC + p);
                } else {
                        /* Only the CPU port, this is compatible with link
                         * aggregation.
                         */
                        ocelot_write_rix(ocelot,
-                                        BIT(ocelot->num_phys_ports),
+                                        BIT(ocelot->cpu),
                                         ANA_PGID_PGID, PGID_SRC + p);
                }
        }