> On 12/17/19 10:40 AM, Lorenzo Bianconi wrote: > >> 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. mt76_insert_hdr_pad takes into account just 802.11 header length and it is 24 or 28 for mgmt frames. Regards, Lorenzo > > > > Regards, > > Lorenzo > I can leave it out of course, but I don't know, if beacons from > mac80211 are always 4B aligned. > > Regards, > Markus > >> + 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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