ravb: Group descriptor types used in Rx ring

The Rx ring can either be made up of normal or extended descriptors, not
a mix of the two at the same time. Make this explicit by grouping the
two variables in a rx_ring union.

The extension of the storage for more than one queue of normal
descriptors from a single to NUM_RX_QUEUE queues have no practical
effect. But aids in making the code readable as the code that uses it
already piggyback on other members of struct ravb_private that are
arrays of max length NUM_RX_QUEUE, e.g. rx_desc_dma. This will also make
further refactoring easier.

While at it, rename the normal descriptor Rx ring to make it clear it's
not strictly related to the GbEthernet E-MAC IP found in RZ/G2L, normal
descriptors could be used on R-Car SoCs too.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/renesas/ravb.h

@@ -1092,8 +1092,10 @@ struct ravb_private {
 	struct ravb_desc *desc_bat;
 	dma_addr_t rx_desc_dma[NUM_RX_QUEUE];
 	dma_addr_t tx_desc_dma[NUM_TX_QUEUE];
-	struct ravb_rx_desc *gbeth_rx_ring;
-	struct ravb_ex_rx_desc *rx_ring[NUM_RX_QUEUE];
+	union {
+		struct ravb_rx_desc *desc;
+		struct ravb_ex_rx_desc *ex_desc;
+	} rx_ring[NUM_RX_QUEUE];
 	struct ravb_tx_desc *tx_ring[NUM_TX_QUEUE];
 	void *tx_align[NUM_TX_QUEUE];
 	struct sk_buff *rx_1st_skb;

drivers/net/ethernet/renesas/ravb_main.c

@@ -241,11 +241,11 @@ static void ravb_rx_ring_free_gbeth(struct net_device *ndev, int q)
 	unsigned int ring_size;
 	unsigned int i;
 
-	if (!priv->gbeth_rx_ring)
+	if (!priv->rx_ring[q].desc)
 		return;
 
 	for (i = 0; i < priv->num_rx_ring[q]; i++) {
-		struct ravb_rx_desc *desc = &priv->gbeth_rx_ring[i];
+		struct ravb_rx_desc *desc = &priv->rx_ring[q].desc[i];
 
 		if (!dma_mapping_error(ndev->dev.parent,
 				       le32_to_cpu(desc->dptr)))
@@ -255,9 +255,9 @@ static void ravb_rx_ring_free_gbeth(struct net_device *ndev, int q)
 					 DMA_FROM_DEVICE);
 	}
 	ring_size = sizeof(struct ravb_rx_desc) * (priv->num_rx_ring[q] + 1);
-	dma_free_coherent(ndev->dev.parent, ring_size, priv->gbeth_rx_ring,
+	dma_free_coherent(ndev->dev.parent, ring_size, priv->rx_ring[q].desc,
 			  priv->rx_desc_dma[q]);
-	priv->gbeth_rx_ring = NULL;
+	priv->rx_ring[q].desc = NULL;
 }
 
 static void ravb_rx_ring_free_rcar(struct net_device *ndev, int q)
@@ -266,11 +266,11 @@ static void ravb_rx_ring_free_rcar(struct net_device *ndev, int q)
 	unsigned int ring_size;
 	unsigned int i;
 
-	if (!priv->rx_ring[q])
+	if (!priv->rx_ring[q].ex_desc)
 		return;
 
 	for (i = 0; i < priv->num_rx_ring[q]; i++) {
-		struct ravb_ex_rx_desc *desc = &priv->rx_ring[q][i];
+		struct ravb_ex_rx_desc *desc = &priv->rx_ring[q].ex_desc[i];
 
 		if (!dma_mapping_error(ndev->dev.parent,
 				       le32_to_cpu(desc->dptr)))
@@ -281,9 +281,9 @@ static void ravb_rx_ring_free_rcar(struct net_device *ndev, int q)
 	}
 	ring_size = sizeof(struct ravb_ex_rx_desc) *
 		    (priv->num_rx_ring[q] + 1);
-	dma_free_coherent(ndev->dev.parent, ring_size, priv->rx_ring[q],
+	dma_free_coherent(ndev->dev.parent, ring_size, priv->rx_ring[q].ex_desc,
 			  priv->rx_desc_dma[q]);
-	priv->rx_ring[q] = NULL;
+	priv->rx_ring[q].ex_desc = NULL;
 }
 
 /* Free skb's and DMA buffers for Ethernet AVB */
@@ -335,11 +335,11 @@ static void ravb_rx_ring_format_gbeth(struct net_device *ndev, int q)
 	unsigned int i;
 
 	rx_ring_size = sizeof(*rx_desc) * priv->num_rx_ring[q];
-	memset(priv->gbeth_rx_ring, 0, rx_ring_size);
+	memset(priv->rx_ring[q].desc, 0, rx_ring_size);
 	/* Build RX ring buffer */
 	for (i = 0; i < priv->num_rx_ring[q]; i++) {
 		/* RX descriptor */
-		rx_desc = &priv->gbeth_rx_ring[i];
+		rx_desc = &priv->rx_ring[q].desc[i];
 		rx_desc->ds_cc = cpu_to_le16(GBETH_RX_DESC_DATA_SIZE);
 		dma_addr = dma_map_single(ndev->dev.parent, priv->rx_skb[q][i]->data,
 					  GBETH_RX_BUFF_MAX,
@@ -352,7 +352,7 @@ static void ravb_rx_ring_format_gbeth(struct net_device *ndev, int q)
 		rx_desc->dptr = cpu_to_le32(dma_addr);
 		rx_desc->die_dt = DT_FEMPTY;
 	}
-	rx_desc = &priv->gbeth_rx_ring[i];
+	rx_desc = &priv->rx_ring[q].desc[i];
 	rx_desc->dptr = cpu_to_le32((u32)priv->rx_desc_dma[q]);
 	rx_desc->die_dt = DT_LINKFIX; /* type */
 }
@@ -365,11 +365,11 @@ static void ravb_rx_ring_format_rcar(struct net_device *ndev, int q)
 	dma_addr_t dma_addr;
 	unsigned int i;
 
-	memset(priv->rx_ring[q], 0, rx_ring_size);
+	memset(priv->rx_ring[q].ex_desc, 0, rx_ring_size);
 	/* Build RX ring buffer */
 	for (i = 0; i < priv->num_rx_ring[q]; i++) {
 		/* RX descriptor */
-		rx_desc = &priv->rx_ring[q][i];
+		rx_desc = &priv->rx_ring[q].ex_desc[i];
 		rx_desc->ds_cc = cpu_to_le16(RX_BUF_SZ);
 		dma_addr = dma_map_single(ndev->dev.parent, priv->rx_skb[q][i]->data,
 					  RX_BUF_SZ,
@@ -382,7 +382,7 @@ static void ravb_rx_ring_format_rcar(struct net_device *ndev, int q)
 		rx_desc->dptr = cpu_to_le32(dma_addr);
 		rx_desc->die_dt = DT_FEMPTY;
 	}
-	rx_desc = &priv->rx_ring[q][i];
+	rx_desc = &priv->rx_ring[q].ex_desc[i];
 	rx_desc->dptr = cpu_to_le32((u32)priv->rx_desc_dma[q]);
 	rx_desc->die_dt = DT_LINKFIX; /* type */
 }
@@ -437,10 +437,10 @@ static void *ravb_alloc_rx_desc_gbeth(struct net_device *ndev, int q)
 
 	ring_size = sizeof(struct ravb_rx_desc) * (priv->num_rx_ring[q] + 1);
 
-	priv->gbeth_rx_ring = dma_alloc_coherent(ndev->dev.parent, ring_size,
-						 &priv->rx_desc_dma[q],
-						 GFP_KERNEL);
-	return priv->gbeth_rx_ring;
+	priv->rx_ring[q].desc = dma_alloc_coherent(ndev->dev.parent, ring_size,
+						   &priv->rx_desc_dma[q],
+						   GFP_KERNEL);
+	return priv->rx_ring[q].desc;
 }
 
 static void *ravb_alloc_rx_desc_rcar(struct net_device *ndev, int q)
@@ -450,10 +450,11 @@ static void *ravb_alloc_rx_desc_rcar(struct net_device *ndev, int q)
 
 	ring_size = sizeof(struct ravb_ex_rx_desc) * (priv->num_rx_ring[q] + 1);
 
-	priv->rx_ring[q] = dma_alloc_coherent(ndev->dev.parent, ring_size,
-					      &priv->rx_desc_dma[q],
-					      GFP_KERNEL);
-	return priv->rx_ring[q];
+	priv->rx_ring[q].ex_desc = dma_alloc_coherent(ndev->dev.parent,
+						      ring_size,
+						      &priv->rx_desc_dma[q],
+						      GFP_KERNEL);
+	return priv->rx_ring[q].ex_desc;
 }
 
 /* Init skb and descriptor buffer for Ethernet AVB */
@@ -830,7 +831,7 @@ static bool ravb_rx_gbeth(struct net_device *ndev, int *quota, int q)
 	limit = priv->dirty_rx[q] + priv->num_rx_ring[q] - priv->cur_rx[q];
 	stats = &priv->stats[q];
 
-	desc = &priv->gbeth_rx_ring[entry];
+	desc = &priv->rx_ring[q].desc[entry];
 	for (i = 0; i < limit && rx_packets < *quota && desc->die_dt != DT_FEMPTY; i++) {
 		/* Descriptor type must be checked before all other reads */
 		dma_rmb();
@@ -901,13 +902,13 @@ static bool ravb_rx_gbeth(struct net_device *ndev, int *quota, int q)
 		}
 
 		entry = (++priv->cur_rx[q]) % priv->num_rx_ring[q];
-		desc = &priv->gbeth_rx_ring[entry];
+		desc = &priv->rx_ring[q].desc[entry];
 	}
 
 	/* Refill the RX ring buffers. */
 	for (; priv->cur_rx[q] - priv->dirty_rx[q] > 0; priv->dirty_rx[q]++) {
 		entry = priv->dirty_rx[q] % priv->num_rx_ring[q];
-		desc = &priv->gbeth_rx_ring[entry];
+		desc = &priv->rx_ring[q].desc[entry];
 		desc->ds_cc = cpu_to_le16(GBETH_RX_DESC_DATA_SIZE);
 
 		if (!priv->rx_skb[q][entry]) {
@@ -957,7 +958,7 @@ static bool ravb_rx_rcar(struct net_device *ndev, int *quota, int q)
 
 	boguscnt = min(boguscnt, *quota);
 	limit = boguscnt;
-	desc = &priv->rx_ring[q][entry];
+	desc = &priv->rx_ring[q].ex_desc[entry];
 	while (desc->die_dt != DT_FEMPTY) {
 		/* Descriptor type must be checked before all other reads */
 		dma_rmb();
@@ -1017,13 +1018,13 @@ static bool ravb_rx_rcar(struct net_device *ndev, int *quota, int q)
 		}
 
 		entry = (++priv->cur_rx[q]) % priv->num_rx_ring[q];
-		desc = &priv->rx_ring[q][entry];
+		desc = &priv->rx_ring[q].ex_desc[entry];
 	}
 
 	/* Refill the RX ring buffers. */
 	for (; priv->cur_rx[q] - priv->dirty_rx[q] > 0; priv->dirty_rx[q]++) {
 		entry = priv->dirty_rx[q] % priv->num_rx_ring[q];
-		desc = &priv->rx_ring[q][entry];
+		desc = &priv->rx_ring[q].ex_desc[entry];
 		desc->ds_cc = cpu_to_le16(RX_BUF_SZ);
 
 		if (!priv->rx_skb[q][entry]) {