net: bcmgenet: bcmgenet_init_tx_ring() cleanup

1. Simplify function description
2. Rename function parameter write_ptr to start_ptr to better indicate use
3. Remove unnecessary local variable first_bd
4. Remove out-of-place comment "Unclassified traffic goes to ring 16"
5. Fix TDMA_WRITE_PTR register init
Signed-off-by: NPetri Gynther <pgynther@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/genet/bcmgenet.c

@@ -1680,17 +1680,14 @@ static int init_umac(struct bcmgenet_priv *priv)
 	return 0;
 }
 
-/* Initialize all house-keeping variables for a TX ring, along
- * with corresponding hardware registers
- */
+/* Initialize a Tx ring along with corresponding hardware registers */
 static void bcmgenet_init_tx_ring(struct bcmgenet_priv *priv,
 				  unsigned int index, unsigned int size,
-				  unsigned int write_ptr, unsigned int end_ptr)
+				  unsigned int start_ptr, unsigned int end_ptr)
 {
 	struct bcmgenet_tx_ring *ring = &priv->tx_rings[index];
 	u32 words_per_bd = WORDS_PER_BD(priv);
 	u32 flow_period_val = 0;
-	unsigned int first_bd;
 
 	spin_lock_init(&ring->lock);
 	ring->index = index;
@@ -1703,12 +1700,12 @@ static void bcmgenet_init_tx_ring(struct bcmgenet_priv *priv,
 		ring->int_enable = bcmgenet_tx_ring_int_enable;
 		ring->int_disable = bcmgenet_tx_ring_int_disable;
 	}
-	ring->cbs = priv->tx_cbs + write_ptr;
+	ring->cbs = priv->tx_cbs + start_ptr;
 	ring->size = size;
 	ring->c_index = 0;
 	ring->free_bds = size;
-	ring->write_ptr = write_ptr;
-	ring->cb_ptr = write_ptr;
+	ring->write_ptr = start_ptr;
+	ring->cb_ptr = start_ptr;
 	ring->end_ptr = end_ptr - 1;
 	ring->prod_index = 0;
 
@@ -1722,19 +1719,16 @@ static void bcmgenet_init_tx_ring(struct bcmgenet_priv *priv,
 	/* Disable rate control for now */
 	bcmgenet_tdma_ring_writel(priv, index, flow_period_val,
 				  TDMA_FLOW_PERIOD);
-	/* Unclassified traffic goes to ring 16 */
 	bcmgenet_tdma_ring_writel(priv, index,
 				  ((size << DMA_RING_SIZE_SHIFT) |
 				   RX_BUF_LENGTH), DMA_RING_BUF_SIZE);
 
-	first_bd = write_ptr;
-
 	/* Set start and end address, read and write pointers */
-	bcmgenet_tdma_ring_writel(priv, index, first_bd * words_per_bd,
+	bcmgenet_tdma_ring_writel(priv, index, start_ptr * words_per_bd,
 				  DMA_START_ADDR);
-	bcmgenet_tdma_ring_writel(priv, index, first_bd * words_per_bd,
+	bcmgenet_tdma_ring_writel(priv, index, start_ptr * words_per_bd,
 				  TDMA_READ_PTR);
-	bcmgenet_tdma_ring_writel(priv, index, first_bd,
+	bcmgenet_tdma_ring_writel(priv, index, start_ptr * words_per_bd,
 				  TDMA_WRITE_PTR);
 	bcmgenet_tdma_ring_writel(priv, index, end_ptr * words_per_bd - 1,
 				  DMA_END_ADDR);