net: mvpp2: cls: Use a dedicated lu_type for the RSS lookup

When performing a TCAM lookup in the C2 engine, it's possible that
multiple entries match the packet. To make sure the correct entry match
when performing a lookup, the Flow Table can set a lookup type, which
will be used in the TCAM lookup, thus preventing such false-positives.

We need to make sure the RSS match doesn't interfere with other
classification lookups, hence we use a dedicated lookup_type for it.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mvpp2/mvpp2_cls.c

@@ -596,7 +596,7 @@ static void mvpp2_cls_flow_init(struct mvpp2 *priv,
 
 	mvpp2_cls_flow_eng_set(&fe, MVPP22_CLS_ENGINE_C2);
 	mvpp2_cls_flow_port_id_sel(&fe, true);
-	mvpp2_cls_flow_lu_type_set(&fe, MVPP22_FLOW_ETHERNET);
+	mvpp2_cls_flow_lu_type_set(&fe, MVPP22_CLS_LU_TYPE_ALL);
 
 	/* Add all ports */
 	for (i = 0; i < MVPP2_MAX_PORTS; i++)
@@ -861,7 +861,7 @@ static void mvpp2_port_c2_cls_init(struct mvpp2_port *port)
 
 	/* Match on Lookup Type */
 	c2.tcam[4] |= MVPP22_CLS_C2_TCAM_EN(MVPP22_CLS_C2_LU_TYPE(MVPP2_CLS_LU_TYPE_MASK));
-	c2.tcam[4] |= MVPP22_CLS_C2_LU_TYPE(MVPP22_FLOW_ETHERNET);
+	c2.tcam[4] |= MVPP22_CLS_C2_LU_TYPE(MVPP22_CLS_LU_TYPE_ALL);
 
 	/* Update RSS status after matching this entry */
 	c2.act = MVPP22_CLS_C2_ACT_RSS_EN(MVPP22_C2_UPD_LOCK);

drivers/net/ethernet/marvell/mvpp2/mvpp2_cls.h

@@ -180,6 +180,11 @@ enum mvpp2_prs_flow {
 /* LU Type defined for all engines, and specified in the flow table */
 #define MVPP2_CLS_LU_TYPE_MASK			0x3f
 
+enum mvpp2_cls_lu_type {
+	/* rule->loc is used as a lu-type for the entries 0 - 62. */
+	MVPP22_CLS_LU_TYPE_ALL = 63,
+};
+
 #define MVPP2_N_FLOWS		(MVPP2_FL_LAST - MVPP2_FL_START)
 
 struct mvpp2_cls_flow {