From: Intel <intel.com>
Date: Mon, 22 Jul 2013 22:00:00 +0000 (+0200)
Subject: ixgbe: use DD bit to count RX available descriptors
X-Git-Tag: spdx-start~11174
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=90b2eeb80aa537108f4ad7ddbc0fdeeaa9f7ce90;p=dpdk.git

ixgbe: use DD bit to count RX available descriptors

Signed-off-by: Intel
---

diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
index e9eb83b4f7..8e7cb2693a 100644
--- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
+++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
@@ -2271,29 +2271,32 @@ ixgbe_dev_rx_queue_setup(struct rte_eth_dev *dev,
 	return 0;
 }
 
-uint32_t ixgbe_dev_rx_queue_count(struct rte_eth_dev *dev,
-					uint16_t rx_queue_id)
+uint32_t
+ixgbe_dev_rx_queue_count(struct rte_eth_dev *dev, uint16_t rx_queue_id)
 {
+#define IXGBE_RXQ_SCAN_INTERVAL 4
+	volatile union ixgbe_adv_rx_desc *rxdp;
 	struct igb_rx_queue *rxq;
-	uint32_t nb_pkts_available;
-	uint32_t rx_rdh;
-	uint32_t rx_id;
+	uint32_t desc = 0;
 
 	if (rx_queue_id >= dev->data->nb_rx_queues) {
-	    PMD_RX_LOG(DEBUG,"Invalid RX queue_id=%d\n", rx_queue_id);
-	    return 0;
+		PMD_RX_LOG(ERR, "Invalid RX queue id=%d\n", rx_queue_id);
+		return 0;
 	}
 
 	rxq = dev->data->rx_queues[rx_queue_id];
-	rx_id = (uint16_t)((rxq->rx_tail == 0) ?
-		(rxq->nb_rx_desc - 1) : (rxq->rx_tail - 1));
-	rx_rdh = IXGBE_PCI_REG(rxq->rdh_reg_addr);
-	if (rx_rdh > rx_id) 
-	    nb_pkts_available = rx_rdh - rx_id;
-	else 
-	    nb_pkts_available = rx_rdh - rx_id + rxq->nb_rx_desc;
- 
-	return (nb_pkts_available);
+	rxdp = &(rxq->rx_ring[rxq->rx_tail]);
+
+	while ((desc < rxq->nb_rx_desc) &&
+		(rxdp->wb.upper.status_error & IXGBE_RXDADV_STAT_DD)) {
+		desc += IXGBE_RXQ_SCAN_INTERVAL;
+		rxdp += IXGBE_RXQ_SCAN_INTERVAL;
+		if (rxq->rx_tail + desc >= rxq->nb_rx_desc)
+			rxdp = &(rxq->rx_ring[rxq->rx_tail +
+				desc - rxq->nb_rx_desc]);
+	}
+
+	return desc;
 }
 
 void