net: macb: move ring size computation to functions

The tx/rx ring size calculation is somewhat complex and partially hidden
behind a macro. Move that out of the {RX,TX}_RING_BYTES() macros and
macb_{alloc,free}_consistent() functions into neat separate functions.

In macb_free_consistent(), we drop the size variable and directly call
the size helpers in the arguments list. In macb_alloc_consistent(), we
keep the size variable that is used by netdev_dbg() calls.

Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250923-macb-fixes-v6-3-772d655cdeb6@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: tleb

drivers/net/ethernet/cadence/macb_main.c

@@ -51,14 +51,10 @@ struct sifive_fu540_macb_mgmt {
 #define DEFAULT_RX_RING_SIZE	512 /* must be power of 2 */
 #define MIN_RX_RING_SIZE	64
 #define MAX_RX_RING_SIZE	8192
-#define RX_RING_BYTES(bp)	(macb_dma_desc_get_size(bp)	\
-				 * (bp)->rx_ring_size)
 
 #define DEFAULT_TX_RING_SIZE	512 /* must be power of 2 */
 #define MIN_TX_RING_SIZE	64
 #define MAX_TX_RING_SIZE	4096
-#define TX_RING_BYTES(bp)	(macb_dma_desc_get_size(bp)	\
-				 * (bp)->tx_ring_size)
 
 /* level of occupied TX descriptors under which we wake up TX process */
 #define MACB_TX_WAKEUP_THRESH(bp)	(3 * (bp)->tx_ring_size / 4)
@@ -2470,11 +2466,20 @@ static void macb_free_rx_buffers(struct macb *bp)
 	}
 }
 
+static unsigned int macb_tx_ring_size_per_queue(struct macb *bp)
+{
+	return macb_dma_desc_get_size(bp) * bp->tx_ring_size + bp->tx_bd_rd_prefetch;
+}
+
+static unsigned int macb_rx_ring_size_per_queue(struct macb *bp)
+{
+	return macb_dma_desc_get_size(bp) * bp->rx_ring_size + bp->rx_bd_rd_prefetch;
+}
+
 static void macb_free_consistent(struct macb *bp)
 {
 	struct macb_queue *queue;
 	unsigned int q;
-	int size;
 
 	if (bp->rx_ring_tieoff) {
 		dma_free_coherent(&bp->pdev->dev, macb_dma_desc_get_size(bp),
@@ -2488,14 +2493,14 @@ static void macb_free_consistent(struct macb *bp)
 		kfree(queue->tx_skb);
 		queue->tx_skb = NULL;
 		if (queue->tx_ring) {
-			size = TX_RING_BYTES(bp) + bp->tx_bd_rd_prefetch;
-			dma_free_coherent(&bp->pdev->dev, size,
+			dma_free_coherent(&bp->pdev->dev,
+					  macb_tx_ring_size_per_queue(bp),
 					  queue->tx_ring, queue->tx_ring_dma);
 			queue->tx_ring = NULL;
 		}
 		if (queue->rx_ring) {
-			size = RX_RING_BYTES(bp) + bp->rx_bd_rd_prefetch;
-			dma_free_coherent(&bp->pdev->dev, size,
+			dma_free_coherent(&bp->pdev->dev,
+					  macb_rx_ring_size_per_queue(bp),
 					  queue->rx_ring, queue->rx_ring_dma);
 			queue->rx_ring = NULL;
 		}
@@ -2546,7 +2551,7 @@ static int macb_alloc_consistent(struct macb *bp)
 	int size;
 
 	for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) {
-		size = TX_RING_BYTES(bp) + bp->tx_bd_rd_prefetch;
+		size = macb_tx_ring_size_per_queue(bp);
 		queue->tx_ring = dma_alloc_coherent(&bp->pdev->dev, size,
 						    &queue->tx_ring_dma,
 						    GFP_KERNEL);
@@ -2564,7 +2569,7 @@ static int macb_alloc_consistent(struct macb *bp)
 		if (!queue->tx_skb)
 			goto out_err;
 
-		size = RX_RING_BYTES(bp) + bp->rx_bd_rd_prefetch;
+		size = macb_rx_ring_size_per_queue(bp);
 		queue->rx_ring = dma_alloc_coherent(&bp->pdev->dev, size,
 						    &queue->rx_ring_dma,
 						    GFP_KERNEL);