Commit e6a53218 authored by Sean Anderson's avatar Sean Anderson Committed by Jakub Kicinski
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net: cadence: macb: Implement BQL 



Implement byte queue limits to allow queuing disciplines to account for
packets enqueued in the ring buffer but not yet transmitted. There are a
separate set of transmit functions for AT91 that I haven't touched since
I don't have hardware to test on.

Signed-off-by: default avatarSean Anderson <sean.anderson@linux.dev>
Link: https://patch.msgid.link/20250220164257.96859-1-sean.anderson@linux.dev


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 3e401818

drivers/net/ethernet/cadence/macb_main.c

+18 −2
Original line number Diff line number Diff line
@@ -1079,15 +1079,18 @@ static void macb_tx_error_task(struct work_struct *work) 
						      tx_error_task);

	bool			halt_timeout = false;

	struct macb		*bp = queue->bp;

	u32			queue_index;

	u32			packets = 0;

	u32			bytes = 0;

	struct macb_tx_skb	*tx_skb;

	struct macb_dma_desc	*desc;

	struct sk_buff		*skb;

	unsigned int		tail;

	unsigned long		flags;



	queue_index = queue - bp->queues;

	netdev_vdbg(bp->dev, "macb_tx_error_task: q = %u, t = %u, h = %u\n",

		    (unsigned int)(queue - bp->queues),

		    queue->tx_tail, queue->tx_head);

		    queue_index, queue->tx_tail, queue->tx_head);



	/* Prevent the queue NAPI TX poll from running, as it calls

	 * macb_tx_complete(), which in turn may call netif_wake_subqueue().
@@ -1140,8 +1143,10 @@ static void macb_tx_error_task(struct work_struct *work) 
					    skb->data);

				bp->dev->stats.tx_packets++;

				queue->stats.tx_packets++;

				packets++;

				bp->dev->stats.tx_bytes += skb->len;

				queue->stats.tx_bytes += skb->len;

				bytes += skb->len;

			}

		} else {

			/* "Buffers exhausted mid-frame" errors may only happen
@@ -1158,6 +1163,9 @@ static void macb_tx_error_task(struct work_struct *work) 
		macb_tx_unmap(bp, tx_skb, 0);

	}



	netdev_tx_completed_queue(netdev_get_tx_queue(bp->dev, queue_index),

				  packets, bytes);



	/* Set end of TX queue */

	desc = macb_tx_desc(queue, 0);

	macb_set_addr(bp, desc, 0);
@@ -1228,6 +1236,7 @@ static int macb_tx_complete(struct macb_queue *queue, int budget) 
	unsigned int tail;

	unsigned int head;

	int packets = 0;

	u32 bytes = 0;



	spin_lock(&queue->tx_ptr_lock);

	head = queue->tx_head;
@@ -1269,6 +1278,7 @@ static int macb_tx_complete(struct macb_queue *queue, int budget) 
				bp->dev->stats.tx_bytes += skb->len;

				queue->stats.tx_bytes += skb->len;

				packets++;

				bytes += skb->len;

			}



			/* Now we can safely release resources */
@@ -1283,6 +1293,9 @@ static int macb_tx_complete(struct macb_queue *queue, int budget) 
		}

	}



	netdev_tx_completed_queue(netdev_get_tx_queue(bp->dev, queue_index),

				  packets, bytes);



	queue->tx_tail = tail;

	if (__netif_subqueue_stopped(bp->dev, queue_index) &&

	    CIRC_CNT(queue->tx_head, queue->tx_tail,
@@ -2384,6 +2397,8 @@ static netdev_tx_t macb_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	/* Make newly initialized descriptor visible to hardware */

	wmb();

	skb_tx_timestamp(skb);

	netdev_tx_sent_queue(netdev_get_tx_queue(bp->dev, queue_index),

			     skb->len);



	spin_lock_irq(&bp->lock);

	macb_writel(bp, NCR, macb_readl(bp, NCR) | MACB_BIT(TSTART));
@@ -3019,6 +3034,7 @@ static int macb_close(struct net_device *dev) 
	for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) {

		napi_disable(&queue->napi_rx);

		napi_disable(&queue->napi_tx);

		netdev_tx_reset_queue(netdev_get_tx_queue(dev, q));

	}



	phylink_stop(bp->phylink);