drivers/net/ethernet/netronome/nfp/nfdk/rings.c

Source file repositories/reference/linux-study-clean/drivers/net/ethernet/netronome/nfp/nfdk/rings.c

File Facts

System
Linux kernel
Corpus path
drivers/net/ethernet/netronome/nfp/nfdk/rings.c
Extension
.c
Size
5303 bytes
Lines
198
Domain
Driver Families
Bucket
drivers/net
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (!skb) {
			n_descs = D_BLOCK_CPL(tx_ring->rd_p);
			goto next;
		}

		nr_frags = skb_shinfo(skb)->nr_frags;
		txbuf++;

		/* Unmap head */
		size = skb_headlen(skb);
		dma_unmap_single(dev, txbuf->dma_addr, size, DMA_TO_DEVICE);
		n_descs += nfp_nfdk_headlen_to_segs(size);
		txbuf++;

		frag = skb_shinfo(skb)->frags;
		fend = frag + nr_frags;
		for (; frag < fend; frag++) {
			size = skb_frag_size(frag);
			dma_unmap_page(dev, txbuf->dma_addr,
				       skb_frag_size(frag), DMA_TO_DEVICE);
			n_descs += DIV_ROUND_UP(size,
						NFDK_TX_MAX_DATA_PER_DESC);
			txbuf++;
		}

		if (skb_is_gso(skb))
			n_descs++;

		dev_kfree_skb_any(skb);
next:
		tx_ring->rd_p += n_descs;
	}

	memset(tx_ring->txds, 0, tx_ring->size);
	tx_ring->data_pending = 0;
	tx_ring->wr_p = 0;
	tx_ring->rd_p = 0;
	tx_ring->qcp_rd_p = 0;
	tx_ring->wr_ptr_add = 0;

	if (tx_ring->is_xdp || !dp->netdev)
		return;

	nd_q = netdev_get_tx_queue(dp->netdev, tx_ring->idx);
	netdev_tx_reset_queue(nd_q);
}

static void nfp_nfdk_tx_ring_free(struct nfp_net_tx_ring *tx_ring)
{
	struct nfp_net_r_vector *r_vec = tx_ring->r_vec;
	struct nfp_net_dp *dp = &r_vec->nfp_net->dp;

	kvfree(tx_ring->ktxbufs);

	if (tx_ring->ktxds)
		dma_free_coherent(dp->dev, tx_ring->size,
				  tx_ring->ktxds, tx_ring->dma);

	tx_ring->cnt = 0;
	tx_ring->txbufs = NULL;
	tx_ring->txds = NULL;
	tx_ring->dma = 0;
	tx_ring->size = 0;
}

static int
nfp_nfdk_tx_ring_alloc(struct nfp_net_dp *dp, struct nfp_net_tx_ring *tx_ring)
{
	struct nfp_net_r_vector *r_vec = tx_ring->r_vec;

	tx_ring->cnt = dp->txd_cnt * NFDK_TX_DESC_PER_SIMPLE_PKT;
	tx_ring->size = array_size(tx_ring->cnt, sizeof(*tx_ring->ktxds));
	tx_ring->ktxds = dma_alloc_coherent(dp->dev, tx_ring->size,
					    &tx_ring->dma,
					    GFP_KERNEL | __GFP_NOWARN);
	if (!tx_ring->ktxds) {
		netdev_warn(dp->netdev, "failed to allocate TX descriptor ring memory, requested descriptor count: %d, consider lowering descriptor count\n",
			    tx_ring->cnt);
		goto err_alloc;
	}

	tx_ring->ktxbufs = kvzalloc_objs(*tx_ring->ktxbufs, tx_ring->cnt);
	if (!tx_ring->ktxbufs)
		goto err_alloc;

	if (!tx_ring->is_xdp && dp->netdev)
		netif_set_xps_queue(dp->netdev, &r_vec->affinity_mask,
				    tx_ring->idx);

	return 0;

Annotation

Implementation Notes