Re: [RFC PATCH net-next 07/10] net: hibmcge: Implement rx_poll function to receive packets

[Jijie Shao]

on 2024/7/31 21:23, Joe Damato wrote:
> On Wed, Jul 31, 2024 at 05:42:42PM +0800, Jijie Shao wrote:
> > Implement rx_poll function to read the rx descriptor after
> > receiving the rx interrupt. Adjust the skb based on the
> > descriptor to complete the reception of the packet.
> >
> > Signed-off-by: Jijie Shao <shaojijie@xxxxxxxxxx>
> > ---
> >   .../ethernet/hisilicon/hibmcge/hbg_common.h   |   5 +
> >   .../net/ethernet/hisilicon/hibmcge/hbg_hw.c   |  10 ++
> >   .../net/ethernet/hisilicon/hibmcge/hbg_hw.h   |   1 +
> >   .../net/ethernet/hisilicon/hibmcge/hbg_irq.c  |   9 +-
> >   .../net/ethernet/hisilicon/hibmcge/hbg_main.c |   2 +
> >   .../net/ethernet/hisilicon/hibmcge/hbg_reg.h  |   2 +
> >   .../hisilicon/hibmcge/hbg_reg_union.h         |  65 ++++++++
> >   .../net/ethernet/hisilicon/hibmcge/hbg_txrx.c | 157 +++++++++++++++++-
> >   8 files changed, 248 insertions(+), 3 deletions(-)
>   
> > diff --git a/drivers/net/ethernet/hisilicon/hibmcge/hbg_main.c b/drivers/net/ethernet/hisilicon/hibmcge/hbg_main.c
> > index 8efeea9b0c26..bb5f8321da8a 100644
> > --- a/drivers/net/ethernet/hisilicon/hibmcge/hbg_main.c
> > +++ b/drivers/net/ethernet/hisilicon/hibmcge/hbg_main.c
> > @@ -36,6 +36,7 @@ static int hbg_net_open(struct net_device *dev)
> >   		return 0;
> >   
> >   	netif_carrier_off(dev);
> > +	napi_enable(&priv->rx_ring.napi);
> >   	napi_enable(&priv->tx_ring.napi);
> >   	hbg_enable_intr(priv, true);
> >   	hbg_hw_mac_enable(priv, HBG_STATUS_ENABLE);
> In the future, it might be good to consider using:
>     - netif_napi_set_irq
>     - netif_queue_set_napi
>   
> to link NAPIs with IRQs and queues.
Sounds good, but I can't find these two functions in 6.4 kernel?

> > +static int hbg_rx_fill_buffers(struct hbg_priv *priv)
> > +{
> > +	struct hbg_ring *ring = &priv->rx_ring;
> > +	int ret;
> > +
> > +	while (!(hbg_fifo_is_full(priv, ring->dir) ||
> > +		 hbg_queue_is_full(ring->ntc, ring->ntu, ring))) {
> > +		ret = hbg_rx_fill_one_buffer(priv);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static bool hbg_sync_data_from_hw(struct hbg_priv *priv,
> > +				  struct hbg_buffer *buffer)
> > +{
> > +	struct hbg_rx_desc *rx_desc;
> > +
> > +	/* make sure HW write desc complete */
> > +	dma_rmb();
> > +
> > +	dma_sync_single_for_cpu(&priv->pdev->dev, buffer->skb_dma,
> > +				buffer->skb_len, DMA_FROM_DEVICE);
> > +
> > +	rx_desc = (struct hbg_rx_desc *)buffer->skb->data;
> > +	return rx_desc->len != 0;
> > +}
> Have you looked into using the page pool to simplify some of the
> logic above?

Thanks, but I probably won't use it at the moment.

> > +static int hbg_napi_rx_poll(struct napi_struct *napi, int budget)
> > +{
> > +	struct hbg_ring *ring = container_of(napi, struct hbg_ring, napi);
> > +	struct hbg_priv *priv = ring->priv;
> > +	struct hbg_rx_desc *rx_desc;
> > +	struct hbg_buffer *buffer;
> > +	u32 packet_done = 0;
> > +
> > +	if (unlikely(!hbg_nic_is_open(priv))) {
> > +		napi_complete(napi);
> > +		return 0;
> > +	}
> > +
> > +	while (packet_done < budget) {
> > +		if (unlikely(hbg_queue_is_empty(ring->ntc, ring->ntu)))
> > +			break;
> > +
> > +		buffer = &ring->queue[ring->ntc];
> > +		if (unlikely(!buffer->skb))
> > +			goto next_buffer;
> > +
> > +		if (unlikely(!hbg_sync_data_from_hw(priv, buffer)))
> > +			break;
> > +
> > +		hbg_dma_unmap(buffer);
> > +
> > +		rx_desc = (struct hbg_rx_desc *)buffer->skb->data;
> > +		skb_reserve(buffer->skb, HBG_PACKET_HEAD_SIZE + NET_IP_ALIGN);
> > +		skb_put(buffer->skb, rx_desc->len);
> > +		buffer->skb->protocol = eth_type_trans(buffer->skb, priv->netdev);
> > +
> > +		priv->netdev->stats.rx_bytes += rx_desc->len;
> > +		priv->netdev->stats.rx_packets++;
> > +		netif_receive_skb(buffer->skb);
> Any reason why not napi_gro_receive ?

Is it OK if the MAC does not support gro?

> > +		buffer->skb = NULL;
> > +		hbg_rx_fill_one_buffer(priv);
> > +
> > +next_buffer:
> > +		hbg_queue_move_next(ntc, ring);
> > +		packet_done++;
> > +	}
> > +
> > +	hbg_rx_fill_buffers(priv);
> > +	if (packet_done >= budget)
> > +		return packet_done;
> > +
> > +	napi_complete(napi);
> Maybe:
>
>     if (napi_complete_done(napi))
>       hbg_irq_enable(priv, HBG_IRQ_RX, true);

okay, I will fix it in v2

Thanks again,

Jijie Shao