net: microchip: sparx5: Find VCAP lookup from chain id

Add a helper function that finds the lookup index in a VCAP instance from
the chain id.
Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/microchip/vcap/vcap_api.c

@@ -644,6 +644,23 @@ static int vcap_write_rule(struct vcap_rule_internal *ri)
 	return 0;
 }
 
+/* Convert a chain id to a VCAP lookup index */
+int vcap_chain_id_to_lookup(struct vcap_admin *admin, int cur_cid)
+{
+	int lookup_first = admin->vinst * admin->lookups_per_instance;
+	int lookup_last = lookup_first + admin->lookups_per_instance;
+	int cid_next = admin->first_cid + VCAP_CID_LOOKUP_SIZE;
+	int cid = admin->first_cid;
+	int lookup;
+
+	for (lookup = lookup_first; lookup < lookup_last; ++lookup,
+	     cid += VCAP_CID_LOOKUP_SIZE, cid_next += VCAP_CID_LOOKUP_SIZE)
+		if (cur_cid >= cid && cur_cid < cid_next)
+			return lookup;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vcap_chain_id_to_lookup);
+
 /* Lookup a vcap instance using chain id */
 struct vcap_admin *vcap_find_admin(struct vcap_control *vctrl, int cid)
 {

drivers/net/ethernet/microchip/vcap/vcap_api_client.h

@@ -184,6 +184,8 @@ int vcap_rule_add_action_u32(struct vcap_rule *rule,
 			     enum vcap_action_field action, u32 value);
 
 /* VCAP lookup operations */
+/* Convert a chain id to a VCAP lookup index */
+int vcap_chain_id_to_lookup(struct vcap_admin *admin, int cur_cid);
 /* Lookup a vcap instance using chain id */
 struct vcap_admin *vcap_find_admin(struct vcap_control *vctrl, int cid);
 /* Find information on a key field in a rule */