[PATCH net-next v1 5/5] net: lan743x: add byte queue limits support

[Chris Babroski <cbabroski@nvidia.com>]

Report the bytes queued to and completed by each TX ring to BQL.

Besides limiting how much data sits in the TX ring, this lets the stack
stop a queue once the bytes in flight exceed the BQL limit. Without it,
a queue is only stopped when its 128 entry ring is full, and the TX
watchdog only looks at stopped queues. With light traffic it can take
tens of seconds after a TX hang to fill the ring, before the watchdog
timeout even starts counting.

lan743x_tx_close() frees pending descriptors without completing them,
so reset the BQL state there.

Assisted-by: LLM
Signed-off-by: Chris Babroski <cbabroski@nvidia.com>
---
 drivers/net/ethernet/microchip/lan743x_main.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c
index 2545a846478d..7739fa49fc44 100644
--- a/drivers/net/ethernet/microchip/lan743x_main.c
+++ b/drivers/net/ethernet/microchip/lan743x_main.c
@@ -1708,10 +1708,23 @@ static int lan743x_tx_next_index(struct lan743x_tx *tx, int index)
 
 static void lan743x_tx_release_completed_descriptors(struct lan743x_tx *tx)
 {
+	struct lan743x_tx_buffer_info *buffer_info;
+	unsigned int bytes = 0;
+	unsigned int pkts = 0;
+
 	while (le32_to_cpu(*tx->head_cpu_ptr) != (tx->last_head)) {
+		buffer_info = &tx->buffer_info[tx->last_head];
+		if (buffer_info->skb) {
+			bytes += buffer_info->skb->len;
+			pkts++;
+		}
 		lan743x_tx_release_desc(tx, tx->last_head, false);
 		tx->last_head = lan743x_tx_next_index(tx, tx->last_head);
 	}
+
+	netdev_tx_completed_queue(netdev_get_tx_queue(tx->adapter->netdev,
+						      tx->channel_number),
+				  pkts, bytes);
 }
 
 static void lan743x_tx_release_all_descriptors(struct lan743x_tx *tx)
@@ -2003,6 +2016,10 @@ static void lan743x_tx_frame_end(struct lan743x_tx *tx,
 	if (ignore_sync)
 		buffer_info->flags |= TX_BUFFER_INFO_FLAG_IGNORE_SYNC;
 
+	netdev_tx_sent_queue(netdev_get_tx_queue(adapter->netdev,
+						 tx->channel_number),
+			     skb->len);
+
 	tx_descriptor = &tx->ring_cpu_ptr[tx->frame_tail];
 	tx_descriptor->data0 = cpu_to_le32(tx->frame_data0);
 	tx->frame_tail = lan743x_tx_next_index(tx, tx->frame_tail);
@@ -2276,6 +2293,8 @@ static void lan743x_tx_close(struct lan743x_tx *tx)
 				 0, 1000, 20000, 100);
 
 	lan743x_tx_release_all_descriptors(tx);
+	netdev_tx_reset_queue(netdev_get_tx_queue(adapter->netdev,
+						  tx->channel_number));
 
 	tx->rqd_descriptors = 0;
 
-- 
2.34.1