net: stmmac: rearrange RX and TX desc init into per-queue basis

Below functions are made to be per-queue in preparation of XDP ZC:

 __init_dma_rx_desc_rings(struct stmmac_priv *priv, u32 queue, gfp_t flags)
 __init_dma_tx_desc_rings(struct stmmac_priv *priv, u32 queue)

The original functions below are stay maintained for all queue usage:

 init_dma_rx_desc_rings(struct net_device *dev, gfp_t flags)
 init_dma_tx_desc_rings(struct net_device *dev)
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -1575,27 +1575,18 @@ static void stmmac_reinit_rx_buffers(struct stmmac_priv *priv)
 }
 
 /**
- * init_dma_rx_desc_rings - init the RX descriptor rings
- * @dev: net device structure
+ * __init_dma_rx_desc_rings - init the RX descriptor ring (per queue)
+ * @priv: driver private structure
+ * @queue: RX queue index
  * @flags: gfp flag.
  * Description: this function initializes the DMA RX descriptors
  * and allocates the socket buffers. It supports the chained and ring
  * modes.
  */
-static int init_dma_rx_desc_rings(struct net_device *dev, gfp_t flags)
+static int __init_dma_rx_desc_rings(struct stmmac_priv *priv, u32 queue, gfp_t flags)
 {
-	struct stmmac_priv *priv = netdev_priv(dev);
-	u32 rx_count = priv->plat->rx_queues_to_use;
-	int ret = -ENOMEM;
-	int queue;
-
-	/* RX INITIALIZATION */
-	netif_dbg(priv, probe, priv->dev,
-		  "SKB addresses:\nskb\t\tskb data\tdma data\n");
-
-	for (queue = 0; queue < rx_count; queue++) {
 	struct stmmac_rx_queue *rx_q = &priv->rx_queue[queue];
-
+	int ret;
 
 	netif_dbg(priv, probe, priv->dev,
 		  "(%s) dma_rx_phy=0x%08x\n", __func__,
@@ -1613,7 +1604,7 @@ static int init_dma_rx_desc_rings(struct net_device *dev, gfp_t flags)
 
 	ret = stmmac_alloc_rx_buffers(priv, queue, flags);
 	if (ret < 0)
-			goto err_init_rx_buffers;
+		return -ENOMEM;
 
 	rx_q->cur_rx = 0;
 	rx_q->dirty_rx = 0;
@@ -1629,6 +1620,25 @@ static int init_dma_rx_desc_rings(struct net_device *dev, gfp_t flags)
 					 rx_q->dma_rx_phy,
 					 priv->dma_rx_size, 0);
 	}
+
+	return 0;
+}
+
+static int init_dma_rx_desc_rings(struct net_device *dev, gfp_t flags)
+{
+	struct stmmac_priv *priv = netdev_priv(dev);
+	u32 rx_count = priv->plat->rx_queues_to_use;
+	u32 queue;
+	int ret;
+
+	/* RX INITIALIZATION */
+	netif_dbg(priv, probe, priv->dev,
+		  "SKB addresses:\nskb\t\tskb data\tdma data\n");
+
+	for (queue = 0; queue < rx_count; queue++) {
+		ret = __init_dma_rx_desc_rings(priv, queue, flags);
+		if (ret)
+			goto err_init_rx_buffers;
 	}
 
 	return 0;
@@ -1647,21 +1657,17 @@ static int init_dma_rx_desc_rings(struct net_device *dev, gfp_t flags)
 }
 
 /**
- * init_dma_tx_desc_rings - init the TX descriptor rings
- * @dev: net device structure.
+ * __init_dma_tx_desc_rings - init the TX descriptor ring (per queue)
+ * @priv: driver private structure
+ * @queue : TX queue index
  * Description: this function initializes the DMA TX descriptors
  * and allocates the socket buffers. It supports the chained and ring
  * modes.
  */
-static int init_dma_tx_desc_rings(struct net_device *dev)
+static int __init_dma_tx_desc_rings(struct stmmac_priv *priv, u32 queue)
 {
-	struct stmmac_priv *priv = netdev_priv(dev);
-	u32 tx_queue_cnt = priv->plat->tx_queues_to_use;
-	u32 queue;
-	int i;
-
-	for (queue = 0; queue < tx_queue_cnt; queue++) {
 	struct stmmac_tx_queue *tx_q = &priv->tx_queue[queue];
+	int i;
 
 	netif_dbg(priv, probe, priv->dev,
 		  "(%s) dma_tx_phy=0x%08x\n", __func__,
@@ -1681,6 +1687,7 @@ static int init_dma_tx_desc_rings(struct net_device *dev)
 
 	for (i = 0; i < priv->dma_tx_size; i++) {
 		struct dma_desc *p;
+
 		if (priv->extend_desc)
 			p = &((tx_q->dma_etx + i)->basic);
 		else if (tx_q->tbs & STMMAC_TBS_AVAIL)
@@ -1702,7 +1709,20 @@ static int init_dma_tx_desc_rings(struct net_device *dev)
 	tx_q->mss = 0;
 
 	netdev_tx_reset_queue(netdev_get_tx_queue(priv->dev, queue));
-	}
+
+	return 0;
+}
+
+static int init_dma_tx_desc_rings(struct net_device *dev)
+{
+	struct stmmac_priv *priv = netdev_priv(dev);
+	u32 tx_queue_cnt;
+	u32 queue;
+
+	tx_queue_cnt = priv->plat->tx_queues_to_use;
+
+	for (queue = 0; queue < tx_queue_cnt; queue++)
+		__init_dma_tx_desc_rings(priv, queue);
 
 	return 0;
 }