> This patch removes a mt76_wr_copy call from the beacon path to hw.
> The skb which is used in this place gets therefore build with txwi
> inside its data. For mt76 usb drivers, this saves one synchronuous
> copy call over usb, which lets the beacon work complete faster.
>
> In mmio case, there is not enough headroom to put the txwi into the
> skb, it is therefore using an additional mt76_wr_copy, which is fast
> over mmio. Thanks Stanislaw for pointing this out.
>
> Signed-off-by: Markus Theil <markus.theil@xxxxxxxxxxxxx>
> ---
> .../wireless/mediatek/mt76/mt76x02_beacon.c | 20 +++++++++++++++----
> 1 file changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c b/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
> index 1c4bdf88f712..68a4f512319e 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
> @@ -26,15 +26,27 @@ static int
> mt76x02_write_beacon(struct mt76x02_dev *dev, int offset, struct sk_buff *skb)
> {
> int beacon_len = dev->beacon_ops->slot_size;
> - struct mt76x02_txwi txwi;
>
> if (WARN_ON_ONCE(beacon_len < skb->len + sizeof(struct mt76x02_txwi)))
> return -ENOSPC;
>
> - mt76x02_mac_write_txwi(dev, &txwi, skb, NULL, NULL, skb->len);
> + /* USB devices already reserve enough skb headroom for txwi's. This
> + * helps to save slow copies over USB.
> + */
> + if (mt76_is_usb(&dev->mt76)) {
> + struct mt76x02_txwi *txwi;
> +
> + mt76_insert_hdr_pad(skb);
Do we really need mt76_insert_hdr_pad? I think beacon header should be 4B
aligned.
Regards,
Lorenzo
> + txwi = (struct mt76x02_txwi *)(skb->data - sizeof(*txwi));
> + mt76x02_mac_write_txwi(dev, txwi, skb, NULL, NULL, skb->len);
> + skb_push(skb, sizeof(*txwi));
> + } else {
> + struct mt76x02_txwi txwi;
>
> - mt76_wr_copy(dev, offset, &txwi, sizeof(txwi));
> - offset += sizeof(txwi);
> + mt76x02_mac_write_txwi(dev, &txwi, skb, NULL, NULL, skb->len);
> + mt76_wr_copy(dev, offset, &txwi, sizeof(txwi));
> + offset += sizeof(txwi);
> + }
>
> mt76_wr_copy(dev, offset, skb->data, skb->len);
> return 0;
> --
> 2.24.0
>
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