bnxt_en: Workaround Nitro A0 hardware RX bug (part 3).

Allocate napi for special vnic, packets arriving on this
napi will simply be dropped and the buffers will be replenished back
to the HW.
Signed-off-by: Prashant Sreedharan <prashant.sreedharan@broadcom.com>
Signed-off-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -1668,6 +1668,76 @@ static int bnxt_poll_work(struct bnxt *bp, struct bnxt_napi *bnapi, int budget)
 	return rx_pkts;
 }
 
+static int bnxt_poll_nitroa0(struct napi_struct *napi, int budget)
+{
+	struct bnxt_napi *bnapi = container_of(napi, struct bnxt_napi, napi);
+	struct bnxt *bp = bnapi->bp;
+	struct bnxt_cp_ring_info *cpr = &bnapi->cp_ring;
+	struct bnxt_rx_ring_info *rxr = bnapi->rx_ring;
+	struct tx_cmp *txcmp;
+	struct rx_cmp_ext *rxcmp1;
+	u32 cp_cons, tmp_raw_cons;
+	u32 raw_cons = cpr->cp_raw_cons;
+	u32 rx_pkts = 0;
+	bool agg_event = false;
+
+	while (1) {
+		int rc;
+
+		cp_cons = RING_CMP(raw_cons);
+		txcmp = &cpr->cp_desc_ring[CP_RING(cp_cons)][CP_IDX(cp_cons)];
+
+		if (!TX_CMP_VALID(txcmp, raw_cons))
+			break;
+
+		if ((TX_CMP_TYPE(txcmp) & 0x30) == 0x10) {
+			tmp_raw_cons = NEXT_RAW_CMP(raw_cons);
+			cp_cons = RING_CMP(tmp_raw_cons);
+			rxcmp1 = (struct rx_cmp_ext *)
+			  &cpr->cp_desc_ring[CP_RING(cp_cons)][CP_IDX(cp_cons)];
+
+			if (!RX_CMP_VALID(rxcmp1, tmp_raw_cons))
+				break;
+
+			/* force an error to recycle the buffer */
+			rxcmp1->rx_cmp_cfa_code_errors_v2 |=
+				cpu_to_le32(RX_CMPL_ERRORS_CRC_ERROR);
+
+			rc = bnxt_rx_pkt(bp, bnapi, &raw_cons, &agg_event);
+			if (likely(rc == -EIO))
+				rx_pkts++;
+			else if (rc == -EBUSY)	/* partial completion */
+				break;
+		} else if (unlikely(TX_CMP_TYPE(txcmp) ==
+				    CMPL_BASE_TYPE_HWRM_DONE)) {
+			bnxt_hwrm_handler(bp, txcmp);
+		} else {
+			netdev_err(bp->dev,
+				   "Invalid completion received on special ring\n");
+		}
+		raw_cons = NEXT_RAW_CMP(raw_cons);
+
+		if (rx_pkts == budget)
+			break;
+	}
+
+	cpr->cp_raw_cons = raw_cons;
+	BNXT_CP_DB(cpr->cp_doorbell, cpr->cp_raw_cons);
+	writel(DB_KEY_RX | rxr->rx_prod, rxr->rx_doorbell);
+	writel(DB_KEY_RX | rxr->rx_prod, rxr->rx_doorbell);
+
+	if (agg_event) {
+		writel(DB_KEY_RX | rxr->rx_agg_prod, rxr->rx_agg_doorbell);
+		writel(DB_KEY_RX | rxr->rx_agg_prod, rxr->rx_agg_doorbell);
+	}
+
+	if (!bnxt_has_work(bp, cpr) && rx_pkts < budget) {
+		napi_complete(napi);
+		BNXT_CP_DB_REARM(cpr->cp_doorbell, cpr->cp_raw_cons);
+	}
+	return rx_pkts;
+}
+
 static int bnxt_poll(struct napi_struct *napi, int budget)
 {
 	struct bnxt_napi *bnapi = container_of(napi, struct bnxt_napi, napi);
@@ -4758,14 +4828,23 @@ static void bnxt_del_napi(struct bnxt *bp)
 static void bnxt_init_napi(struct bnxt *bp)
 {
 	int i;
+	unsigned int cp_nr_rings = bp->cp_nr_rings;
 	struct bnxt_napi *bnapi;
 
 	if (bp->flags & BNXT_FLAG_USING_MSIX) {
-		for (i = 0; i < bp->cp_nr_rings; i++) {
+		if (BNXT_CHIP_TYPE_NITRO_A0(bp))
+			cp_nr_rings--;
+		for (i = 0; i < cp_nr_rings; i++) {
 			bnapi = bp->bnapi[i];
 			netif_napi_add(bp->dev, &bnapi->napi,
 				       bnxt_poll, 64);
 		}
+		if (BNXT_CHIP_TYPE_NITRO_A0(bp)) {
+			bnapi = bp->bnapi[cp_nr_rings];
+			netif_napi_add(bp->dev, &bnapi->napi,
+				       bnxt_poll_nitroa0, 64);
+			napi_hash_add(&bnapi->napi);
+		}
 	} else {
 		bnapi = bp->bnapi[0];
 		netif_napi_add(bp->dev, &bnapi->napi, bnxt_poll, 64);