net: ocelot: Add PGID_BLACKHOLE

Add a new PGID that is used not to forward frames anywhere. It is used
by MRP to make sure that MRP Test frames will not reach CPU port.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mscc/ocelot.c

@@ -2051,6 +2051,9 @@ int ocelot_init(struct ocelot *ocelot)
 
 		ocelot_write_rix(ocelot, val, ANA_PGID_PGID, i);
 	}
+
+	ocelot_write_rix(ocelot, 0, ANA_PGID_PGID, PGID_BLACKHOLE);
+
 	/* Allow broadcast and unknown L2 multicast to the CPU. */
 	ocelot_rmw_rix(ocelot, ANA_PGID_PGID_PGID(BIT(ocelot->num_phys_ports)),
 		       ANA_PGID_PGID_PGID(BIT(ocelot->num_phys_ports)),

include/soc/mscc/ocelot.h

@@ -51,6 +51,7 @@
  */
 
 /* Reserve some destination PGIDs at the end of the range:
+ * PGID_BLACKHOLE: used for not forwarding the frames
  * PGID_CPU: used for whitelisting certain MAC addresses, such as the addresses
  *           of the switch port net devices, towards the CPU port module.
  * PGID_UC: the flooding destinations for unknown unicast traffic.
@@ -59,6 +60,7 @@
  * PGID_MCIPV6: the flooding destinations for IPv6 multicast traffic.
  * PGID_BC: the flooding destinations for broadcast traffic.
  */
+#define PGID_BLACKHOLE			57
 #define PGID_CPU			58
 #define PGID_UC				59
 #define PGID_MC				60
@@ -73,7 +75,7 @@
 
 #define for_each_nonreserved_multicast_dest_pgid(ocelot, pgid)	\
 	for ((pgid) = (ocelot)->num_phys_ports + 1;		\
-	     (pgid) < PGID_CPU;					\
+	     (pgid) < PGID_BLACKHOLE;				\
 	     (pgid)++)
 
 #define for_each_aggr_pgid(ocelot, pgid)			\