On 12/18/19 2:17 PM, Lorenzo Bianconi wrote:
>> 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
Ok, thanks. Then I drop the call.
Markus
>>> 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
>>>>
