octeontx2-af: Exact match scan from kex profile

CN10KB silicon supports exact match table. Scanning KEX
profile should check for exact match feature is enabled
and then set profile masks properly.

These kex profile masks are required to configure NPC
MCAM drop rules. If there is a miss in exact match table,
these drop rules will drop those packets.
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -208,6 +208,7 @@ enum key_fields {
 	NPC_ERRLEV,
 	NPC_ERRCODE,
 	NPC_LXMB,
+	NPC_EXACT_RESULT,
 	NPC_LA,
 	NPC_LB,
 	NPC_LC,

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

@@ -229,6 +229,25 @@ static bool npc_check_field(struct rvu *rvu, int blkaddr, enum key_fields type,
 	return true;
 }
 
+static void npc_scan_exact_result(struct npc_mcam *mcam, u8 bit_number,
+				  u8 key_nibble, u8 intf)
+{
+	u8 offset = (key_nibble * 4) % 64; /* offset within key word */
+	u8 kwi = (key_nibble * 4) / 64; /* which word in key */
+	u8 nr_bits = 4; /* bits in a nibble */
+	u8 type;
+
+	switch (bit_number) {
+	case 40 ... 43:
+		type = NPC_EXACT_RESULT;
+		break;
+
+	default:
+		return;
+	}
+	npc_set_kw_masks(mcam, type, nr_bits, kwi, offset, intf);
+}
+
 static void npc_scan_parse_result(struct npc_mcam *mcam, u8 bit_number,
 				  u8 key_nibble, u8 intf)
 {
@@ -511,8 +530,8 @@ static int npc_scan_kex(struct rvu *rvu, int blkaddr, u8 intf)
 {
 	struct npc_mcam *mcam = &rvu->hw->mcam;
 	u8 lid, lt, ld, bitnr;
+	u64 cfg, masked_cfg;
 	u8 key_nibble = 0;
-	u64 cfg;
 
 	/* Scan and note how parse result is going to be in key.
 	 * A bit set in PARSE_NIBBLE_ENA corresponds to a nibble from
@@ -520,12 +539,24 @@ static int npc_scan_kex(struct rvu *rvu, int blkaddr, u8 intf)
 	 * will be concatenated in key.
 	 */
 	cfg = rvu_read64(rvu, blkaddr, NPC_AF_INTFX_KEX_CFG(intf));
-	cfg &= NPC_PARSE_NIBBLE;
-	for_each_set_bit(bitnr, (unsigned long *)&cfg, 31) {
+	masked_cfg = cfg & NPC_PARSE_NIBBLE;
+	for_each_set_bit(bitnr, (unsigned long *)&masked_cfg, 31) {
 		npc_scan_parse_result(mcam, bitnr, key_nibble, intf);
 		key_nibble++;
 	}
 
+	/* Ignore exact match bits for mcam entries except the first rule
+	 * which is drop on hit. This first rule is configured explitcitly by
+	 * exact match code.
+	 */
+	masked_cfg = cfg & NPC_EXACT_NIBBLE;
+	bitnr = NPC_EXACT_NIBBLE_START;
+	for_each_set_bit_from(bitnr, (unsigned long *)&masked_cfg,
+			      NPC_EXACT_NIBBLE_START) {
+		npc_scan_exact_result(mcam, bitnr, key_nibble, intf);
+		key_nibble++;
+	}
+
 	/* Scan and note how layer data is going to be in key */
 	for (lid = 0; lid < NPC_MAX_LID; lid++) {
 		for (lt = 0; lt < NPC_MAX_LT; lt++) {