netdev - [PATCH net-next 3/4] net: bcmgenet: reclaim transmitted buffers in NAPI context

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Date:	Fri, 24 Oct 2014 13:02:21 -0700
From:	Florian Fainelli <f.fainelli@...il.com>
To:	netdev@...r.kernel.org
Cc:	davem@...emloft.net, pgynther@...gle.com,
	Florian Fainelli <f.fainelli@...il.com>
Subject: [PATCH net-next 3/4] net: bcmgenet: reclaim transmitted buffers in NAPI context

The GENET driver is currently reclaiming transmitted buffers from hard
interrupt context in bcmgenet_isr0 as well as NAPI context in
bcmgenet_poll, which is not consistent and not ideal. Instead, update
the driver to reclaim transmitted buffers in NAPI context only and
properly switch the TX path to use interrupt mitigation based on NAPI.

Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
---
 drivers/net/ethernet/broadcom/genet/bcmgenet.c | 29 +++++++++-----------------
 1 file changed, 10 insertions(+), 19 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
index 70f2fb366375..d6f4a7ace05e 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
@@ -934,9 +934,6 @@ static unsigned int __bcmgenet_tx_reclaim(struct net_device *dev,
 		last_c_index &= (num_tx_bds - 1);
 	}
 
-	if (ring->free_bds > (MAX_SKB_FRAGS + 1))
-		ring->int_disable(priv, ring);
-
 	if (netif_tx_queue_stopped(txq) && pkts_compl)
 		netif_tx_wake_queue(txq);
 
@@ -1211,10 +1208,8 @@ static netdev_tx_t bcmgenet_xmit(struct sk_buff *skb, struct net_device *dev)
 	bcmgenet_tdma_ring_writel(priv, ring->index,
 				  ring->prod_index, TDMA_PROD_INDEX);
 
-	if (ring->free_bds <= (MAX_SKB_FRAGS + 1)) {
+	if (ring->free_bds <= (MAX_SKB_FRAGS + 1))
 		netif_tx_stop_queue(txq);
-		ring->int_enable(priv, ring);
-	}
 
 out:
 	spin_unlock_irqrestore(&ring->lock, flags);
@@ -1553,9 +1548,9 @@ static int init_umac(struct bcmgenet_priv *priv)
 
 	bcmgenet_intr_disable(priv);
 
-	cpu_mask_clear = UMAC_IRQ_RXDMA_MASK;
+	cpu_mask_clear = UMAC_IRQ_RX_TX_MASK;
 
-	dev_dbg(kdev, "%s:Enabling RXDMA interrupts\n", __func__);
+	dev_dbg(kdev, "%s:Enabling RXDMA & TXDMA interrupts\n", __func__);
 
 	/* Monitor cable plug/unplugged event for internal PHY */
 	if (phy_is_internal(priv->phydev)) {
@@ -1879,10 +1874,10 @@ static int bcmgenet_poll(struct napi_struct *napi, int budget)
 {
 	struct bcmgenet_priv *priv = container_of(napi,
 			struct bcmgenet_priv, napi);
-	unsigned int work_done;
+	unsigned int work_done, tx_work;
 
 	/* tx reclaim */
-	bcmgenet_tx_reclaim(priv->dev, &priv->tx_rings[DESC_INDEX]);
+	tx_work = bcmgenet_tx_reclaim(priv->dev, &priv->tx_rings[DESC_INDEX]);
 
 	work_done = bcmgenet_desc_rx(priv, budget);
 
@@ -1891,9 +1886,9 @@ static int bcmgenet_poll(struct napi_struct *napi, int budget)
 	priv->rx_c_index &= DMA_C_INDEX_MASK;
 	bcmgenet_rdma_ring_writel(priv, DESC_INDEX,
 				  priv->rx_c_index, RDMA_CONS_INDEX);
-	if (work_done < budget) {
+	if (work_done < budget || tx_work == 0) {
 		napi_complete(napi);
-		bcmgenet_intrl2_0_writel(priv, UMAC_IRQ_RXDMA_MASK,
+		bcmgenet_intrl2_0_writel(priv, UMAC_IRQ_RX_TX_MASK,
 					 INTRL2_CPU_MASK_CLEAR);
 	}
 
@@ -1968,22 +1963,18 @@ static irqreturn_t bcmgenet_isr0(int irq, void *dev_id)
 	netif_dbg(priv, intr, priv->dev,
 		  "IRQ=0x%x\n", priv->irq0_stat);
 
-	if (priv->irq0_stat & UMAC_IRQ_RXDMA_MASK) {
+	if (priv->irq0_stat & UMAC_IRQ_RX_TX_MASK) {
 		/* We use NAPI(software interrupt throttling, if
 		 * Rx Descriptor throttling is not used.
 		 * Disable interrupt, will be enabled in the poll method.
 		 */
 		if (likely(napi_schedule_prep(&priv->napi))) {
-			bcmgenet_intrl2_0_writel(priv, UMAC_IRQ_RXDMA_MASK,
+			bcmgenet_intrl2_0_writel(priv, UMAC_IRQ_RX_TX_MASK,
 						 INTRL2_CPU_MASK_SET);
 			__napi_schedule(&priv->napi);
 		}
 	}
-	if (priv->irq0_stat &
-			(UMAC_IRQ_TXDMA_BDONE | UMAC_IRQ_TXDMA_PDONE)) {
-		/* Tx reclaim */
-		bcmgenet_tx_reclaim(priv->dev, &priv->tx_rings[DESC_INDEX]);
-	}
+
 	if (priv->irq0_stat & (UMAC_IRQ_PHY_DET_R |
 				UMAC_IRQ_PHY_DET_F |
 				UMAC_IRQ_LINK_UP |
-- 
1.9.1

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