[PATCH net-next] net: airoha: Implement BQL support

Lorenzo Bianconi
2024-09-30T13:21:05Z

Introduce BQL support in the airoha_eth driver to avoid queuing to much
packets into the device hw queues and keep the latency small.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
drivers/net/ethernet/mediatek/airoha_eth.c | 27 ++++++++++++++++++---------
1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/airoha_eth.c b/drivers/net/ethernet/mediatek/airoha_eth.c
index 930f180688e5..6dfde2828d93 100644
--- a/drivers/net/ethernet/mediatek/airoha_eth.c
+++ b/drivers/net/ethernet/mediatek/airoha_eth.c
@@ -786,6 +786,7 @@ struct airoha_hw_stats {
};

struct airoha_qdma {
+ struct airoha_gdm_port *port;
struct airoha_eth *eth;
void __iomem *regs;

@@ -1658,6 +1659,7 @@ static int airoha_qdma_tx_napi_poll(struct napi_struct *napi, int budget)

while (irq_q->queued > 0 && done < budget) {
u32 qid, last, val = irq_q->q[irq_q->head];
+ u32 bytes = 0, count = 0;
struct airoha_queue *q;

if (val == 0xff)
@@ -1684,7 +1686,6 @@ static int airoha_qdma_tx_napi_poll(struct napi_struct *napi, int budget)
struct airoha_qdma_desc *desc = &q->desc[q->tail];
struct airoha_queue_entry *e = &q->entry[q->tail];
u32 desc_ctrl = le32_to_cpu(desc->ctrl);
- struct sk_buff *skb = e->skb;
u16 index = q->tail;

if (!(desc_ctrl & QDMA_DESC_DONE_MASK) &&
@@ -1700,15 +1701,11 @@ static int airoha_qdma_tx_napi_poll(struct napi_struct *napi, int budget)
WRITE_ONCE(desc->msg0, 0);
WRITE_ONCE(desc->msg1, 0);

- if (skb) {
- struct netdev_queue *txq;
-
- txq = netdev_get_tx_queue(skb->dev, qid);
- if (netif_tx_queue_stopped(txq) &&
- q->ndesc - q->queued >= q->free_thr)
- netif_tx_wake_queue(txq);
+ if (e->skb) {
+ bytes += e->skb->len;
+ count++;

- dev_kfree_skb_any(skb);
+ dev_kfree_skb_any(e->skb);
e->skb = NULL;
}

@@ -1716,6 +1713,16 @@ static int airoha_qdma_tx_napi_poll(struct napi_struct *napi, int budget)
break;
}

+ if (qdma->port) {
+ struct netdev_queue *txq;
+
+ txq = netdev_get_tx_queue(qdma->port->dev, qid);
+ netdev_tx_completed_queue(txq, count, bytes);
+ if (netif_tx_queue_stopped(txq) &&
+ q->ndesc - q->queued >= q->free_thr)
+ netif_tx_wake_queue(txq);
+ }
+
spin_unlock_bh(&q->lock);
}

@@ -2482,6 +2489,7 @@ static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb,
q->head = index;
q->queued += i;

+ netdev_tx_sent_queue(txq, skb->len);
skb_tx_timestamp(skb);
if (q->ndesc - q->queued < q->free_thr)
netif_tx_stop_queue(txq);
@@ -2650,6 +2658,7 @@ static int airoha_alloc_gdm_port(struct airoha_eth *eth, struct device_node *np)
port->dev = dev;
port->id = id;
eth->ports[index] = port;
+ qdma->port = port;

return register_netdev(dev);
}

---
base-commit: c824deb1a89755f70156b5cdaf569fca80698719
change-id: 20240930-en7581-bql-552566f2078e

Best regards,
--
Lorenzo Bianconi <lorenzo@kernel.org>