octeontx2-af: Add support for dynamic flow cfg to RSS field generation

Introduce state-based algorithm to convert the flow_key value
to RSS algo field used by NIX_AF_RX_FLOW_KEY_ALGX_FIELDX register.

The outer `for loop` goes over _all_ protocol field and the following
variables depict the state machine forward progress logic.

a) keyoff_marker - Enabled when hash byte length needs to be accounted
in field->key_offset update.
b) field_marker - Enabled when a new field needs to be selected.
c) group_member - Enabled when a protocol is part of a group.

This would remove the existing hard coding and enable to add
new protocol support seamlessly.
Signed-off-by: Jerin Jacob <jerinj@marvell.com>
Signed-off-by: Nithin Dabilpuram <ndabilpuram@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/octeontx2/af/mbox.h

@@ -414,6 +414,7 @@ enum nix_af_status {
 	NIX_AF_INVAL_TXSCHQ_CFG     = -412,
 	NIX_AF_SMQ_FLUSH_FAILED     = -413,
 	NIX_AF_ERR_LF_RESET         = -414,
+	NIX_AF_ERR_RSS_NOSPC_FIELD  = -415,
 	NIX_AF_INVAL_NPA_PF_FUNC    = -419,
 	NIX_AF_INVAL_SSO_PF_FUNC    = -420,
 };

drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c

@@ -1650,80 +1650,139 @@ int rvu_mbox_handler_nix_rss_flowkey_cfg(struct rvu *rvu,
 	return 0;
 }
 
-static void set_flowkey_fields(struct nix_rx_flowkey_alg *alg, u32 flow_cfg)
+static int set_flowkey_fields(struct nix_rx_flowkey_alg *alg, u32 flow_cfg)
 {
-	struct nix_rx_flowkey_alg *field = NULL;
-	int idx, key_type;
+	int idx, nr_field, key_off, field_marker, keyoff_marker;
+	int max_key_off, max_bit_pos, group_member;
+	struct nix_rx_flowkey_alg *field;
+	struct nix_rx_flowkey_alg tmp;
+	u32 key_type, valid_key;
 
 	if (!alg)
-		return;
+		return -EINVAL;
 
-	/* FIELD0: IPv4
-	 * FIELD1: IPv6
-	 * FIELD2: TCP/UDP/SCTP/ALL
-	 * FIELD3: Unused
-	 * FIELD4: Unused
-	 *
-	 * Each of the 32 possible flow key algorithm definitions should
+#define FIELDS_PER_ALG  5
+#define MAX_KEY_OFF	40
+	/* Clear all fields */
+	memset(alg, 0, sizeof(uint64_t) * FIELDS_PER_ALG);
+
+	/* Each of the 32 possible flow key algorithm definitions should
 	 * fall into above incremental config (except ALG0). Otherwise a
 	 * single NPC MCAM entry is not sufficient for supporting RSS.
 	 *
 	 * If a different definition or combination needed then NPC MCAM
 	 * has to be programmed to filter such pkts and it's action should
 	 * point to this definition to calculate flowtag or hash.
+	 *
+	 * The `for loop` goes over _all_ protocol field and the following
+	 * variables depicts the state machine forward progress logic.
+	 *
+	 * keyoff_marker - Enabled when hash byte length needs to be accounted
+	 * in field->key_offset update.
+	 * field_marker - Enabled when a new field needs to be selected.
+	 * group_member - Enabled when protocol is part of a group.
 	 */
-	for (idx = 0; idx < 32; idx++) {
-		key_type = flow_cfg & BIT_ULL(idx);
-		if (!key_type)
-			continue;
+
+	keyoff_marker = 0; max_key_off = 0; group_member = 0;
+	nr_field = 0; key_off = 0; field_marker = 1;
+	field = &tmp; max_bit_pos = fls(flow_cfg);
+	for (idx = 0;
+	     idx < max_bit_pos && nr_field < FIELDS_PER_ALG &&
+	     key_off < MAX_KEY_OFF; idx++) {
+		key_type = BIT(idx);
+		valid_key = flow_cfg & key_type;
+		/* Found a field marker, reset the field values */
+		if (field_marker)
+			memset(&tmp, 0, sizeof(tmp));
+
 		switch (key_type) {
 		case NIX_FLOW_KEY_TYPE_PORT:
-			field = &alg[0];
 			field->sel_chan = true;
 			/* This should be set to 1, when SEL_CHAN is set */
 			field->bytesm1 = 1;
+			field_marker = true;
+			keyoff_marker = true;
 			break;
 		case NIX_FLOW_KEY_TYPE_IPV4:
-			field = &alg[0];
 			field->lid = NPC_LID_LC;
 			field->ltype_match = NPC_LT_LC_IP;
 			field->hdr_offset = 12; /* SIP offset */
 			field->bytesm1 = 7; /* SIP + DIP, 8 bytes */
 			field->ltype_mask = 0xF; /* Match only IPv4 */
+			field_marker = true;
+			keyoff_marker = false;
 			break;
 		case NIX_FLOW_KEY_TYPE_IPV6:
-			field = &alg[1];
 			field->lid = NPC_LID_LC;
 			field->ltype_match = NPC_LT_LC_IP6;
 			field->hdr_offset = 8; /* SIP offset */
 			field->bytesm1 = 31; /* SIP + DIP, 32 bytes */
 			field->ltype_mask = 0xF; /* Match only IPv6 */
+			field_marker = true;
+			keyoff_marker = true;
 			break;
 		case NIX_FLOW_KEY_TYPE_TCP:
 		case NIX_FLOW_KEY_TYPE_UDP:
 		case NIX_FLOW_KEY_TYPE_SCTP:
-			field = &alg[2];
 			field->lid = NPC_LID_LD;
 			field->bytesm1 = 3; /* Sport + Dport, 4 bytes */
-			if (key_type == NIX_FLOW_KEY_TYPE_TCP)
+			if (key_type == NIX_FLOW_KEY_TYPE_TCP && valid_key) {
 				field->ltype_match |= NPC_LT_LD_TCP;
-			else if (key_type == NIX_FLOW_KEY_TYPE_UDP)
+				group_member = true;
+			} else if (key_type == NIX_FLOW_KEY_TYPE_UDP &&
+				   valid_key) {
 				field->ltype_match |= NPC_LT_LD_UDP;
-			else if (key_type == NIX_FLOW_KEY_TYPE_SCTP)
+				group_member = true;
+			} else if (key_type == NIX_FLOW_KEY_TYPE_SCTP &&
+				   valid_key) {
 				field->ltype_match |= NPC_LT_LD_SCTP;
-			field->key_offset = 32; /* After IPv4/v6 SIP, DIP */
+				group_member = true;
+			}
 			field->ltype_mask = ~field->ltype_match;
+			if (key_type == NIX_FLOW_KEY_TYPE_SCTP) {
+				/* Handle the case where any of the group item
+				 * is enabled in the group but not the final one
+				 */
+				if (group_member) {
+					valid_key = true;
+					group_member = false;
+				}
+				field_marker = true;
+				keyoff_marker = true;
+			} else {
+				field_marker = false;
+				keyoff_marker = false;
+			}
 			break;
 		}
-		if (field)
 		field->ena = 1;
-		field = NULL;
+
+		/* Found a valid flow key type */
+		if (valid_key) {
+			field->key_offset = key_off;
+			memcpy(&alg[nr_field], field, sizeof(*field));
+			max_key_off = max(max_key_off, field->bytesm1 + 1);
+
+			/* Found a field marker, get the next field */
+			if (field_marker)
+				nr_field++;
 		}
+
+		/* Found a keyoff marker, update the new key_off */
+		if (keyoff_marker) {
+			key_off += max_key_off;
+			max_key_off = 0;
+		}
+	}
+	/* Processed all the flow key types */
+	if (idx == max_bit_pos && key_off <= MAX_KEY_OFF)
+		return 0;
+	else
+		return NIX_AF_ERR_RSS_NOSPC_FIELD;
 }
 
 static void nix_rx_flowkey_alg_cfg(struct rvu *rvu, int blkaddr)
 {
-#define FIELDS_PER_ALG	5
 	u64 field[NIX_FLOW_KEY_ALG_MAX][FIELDS_PER_ALG];
 	u32 flowkey_cfg, minkey_cfg;
 	int alg, fid;