linux/drivers/net/ethernet/intel/ice/ice_txrx_lib.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2019, Intel Corporation. */

#include <linux/filter.h>

#include "ice_txrx_lib.h"
#include "ice_eswitch.h"
#include "ice_lib.h"

/**
 * ice_release_rx_desc - Store the new tail and head values
 * @rx_ring: ring to bump
 * @val: new head index
 */
void ice_release_rx_desc(struct ice_rx_ring *rx_ring, u16 val)
{
	u16 prev_ntu = rx_ring->next_to_use & ~0x7;

	rx_ring->next_to_use = val;

	/* update next to alloc since we have filled the ring */
	rx_ring->next_to_alloc = val;

	/* QRX_TAIL will be updated with any tail value, but hardware ignores
	 * the lower 3 bits. This makes it so we only bump tail on meaningful
	 * boundaries. Also, this allows us to bump tail on intervals of 8 up to
	 * the budget depending on the current traffic load.
	 */
	val &= ~0x7;
	if (prev_ntu != val) {
		/* Force memory writes to complete before letting h/w
		 * know there are new descriptors to fetch. (Only
		 * applicable for weak-ordered memory model archs,
		 * such as IA-64).
		 */
		wmb();
		writel(val, rx_ring->tail);
	}
}

/**
 * ice_ptype_to_htype - get a hash type
 * @ptype: the ptype value from the descriptor
 *
 * Returns appropriate hash type (such as PKT_HASH_TYPE_L2/L3/L4) to be used by
 * skb_set_hash based on PTYPE as parsed by HW Rx pipeline and is part of
 * Rx desc.
 */
static enum pkt_hash_types ice_ptype_to_htype(u16 ptype)
{
	struct ice_rx_ptype_decoded decoded = ice_decode_rx_desc_ptype(ptype);

	if (!decoded.known)
		return PKT_HASH_TYPE_NONE;
	if (decoded.payload_layer == ICE_RX_PTYPE_PAYLOAD_LAYER_PAY4)
		return PKT_HASH_TYPE_L4;
	if (decoded.payload_layer == ICE_RX_PTYPE_PAYLOAD_LAYER_PAY3)
		return PKT_HASH_TYPE_L3;
	if (decoded.outer_ip == ICE_RX_PTYPE_OUTER_L2)
		return PKT_HASH_TYPE_L2;

	return PKT_HASH_TYPE_NONE;
}

/**
 * ice_rx_hash - set the hash value in the skb
 * @rx_ring: descriptor ring
 * @rx_desc: specific descriptor
 * @skb: pointer to current skb
 * @rx_ptype: the ptype value from the descriptor
 */
static void
ice_rx_hash(struct ice_rx_ring *rx_ring, union ice_32b_rx_flex_desc *rx_desc,
	    struct sk_buff *skb, u16 rx_ptype)
{
	struct ice_32b_rx_flex_desc_nic *nic_mdid;
	u32 hash;

	if (!(rx_ring->netdev->features & NETIF_F_RXHASH))
		return;

	if (rx_desc->wb.rxdid != ICE_RXDID_FLEX_NIC)
		return;

	nic_mdid = (struct ice_32b_rx_flex_desc_nic *)rx_desc;
	hash = le32_to_cpu(nic_mdid->rss_hash);
	skb_set_hash(skb, hash, ice_ptype_to_htype(rx_ptype));
}

/**
 * ice_rx_csum - Indicate in skb if checksum is good
 * @ring: the ring we care about
 * @skb: skb currently being received and modified
 * @rx_desc: the receive descriptor
 * @ptype: the packet type decoded by hardware
 *
 * skb->protocol must be set before this function is called
 */
static void
ice_rx_csum(struct ice_rx_ring *ring, struct sk_buff *skb,
	    union ice_32b_rx_flex_desc *rx_desc, u16 ptype)
{
	struct ice_rx_ptype_decoded decoded;
	u16 rx_status0, rx_status1;
	bool ipv4, ipv6;

	rx_status0 = le16_to_cpu(rx_desc->wb.status_error0);
	rx_status1 = le16_to_cpu(rx_desc->wb.status_error1);

	decoded = ice_decode_rx_desc_ptype(ptype);

	/* Start with CHECKSUM_NONE and by default csum_level = 0 */
	skb->ip_summed = CHECKSUM_NONE;
	skb_checksum_none_assert(skb);

	/* check if Rx checksum is enabled */
	if (!(ring->netdev->features & NETIF_F_RXCSUM))
		return;

	/* check if HW has decoded the packet and checksum */
	if (!(rx_status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_L3L4P_S)))
		return;

	if (!(decoded.known && decoded.outer_ip))
		return;

	ipv4 = (decoded.outer_ip == ICE_RX_PTYPE_OUTER_IP) &&
	       (decoded.outer_ip_ver == ICE_RX_PTYPE_OUTER_IPV4);
	ipv6 = (decoded.outer_ip == ICE_RX_PTYPE_OUTER_IP) &&
	       (decoded.outer_ip_ver == ICE_RX_PTYPE_OUTER_IPV6);

	if (ipv4 && (rx_status0 & (BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_IPE_S) |
				   BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_EIPE_S))))
		goto checksum_fail;

	if (ipv6 && (rx_status0 & (BIT(ICE_RX_FLEX_DESC_STATUS0_IPV6EXADD_S))))
		goto checksum_fail;

	/* check for L4 errors and handle packets that were not able to be
	 * checksummed due to arrival speed
	 */
	if (rx_status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_L4E_S))
		goto checksum_fail;

	/* check for outer UDP checksum error in tunneled packets */
	if ((rx_status1 & BIT(ICE_RX_FLEX_DESC_STATUS1_NAT_S)) &&
	    (rx_status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_EUDPE_S)))
		goto checksum_fail;

	/* If there is an outer header present that might contain a checksum
	 * we need to bump the checksum level by 1 to reflect the fact that
	 * we are indicating we validated the inner checksum.
	 */
	if (decoded.tunnel_type >= ICE_RX_PTYPE_TUNNEL_IP_GRENAT)
		skb->csum_level = 1;

	/* Only report checksum unnecessary for TCP, UDP, or SCTP */
	switch (decoded.inner_prot) {
	case ICE_RX_PTYPE_INNER_PROT_TCP:
	case ICE_RX_PTYPE_INNER_PROT_UDP:
	case ICE_RX_PTYPE_INNER_PROT_SCTP:
		skb->ip_summed = CHECKSUM_UNNECESSARY;
		break;
	default:
		break;
	}
	return;

checksum_fail:
	ring->vsi->back->hw_csum_rx_error++;
}

/**
 * ice_process_skb_fields - Populate skb header fields from Rx descriptor
 * @rx_ring: Rx descriptor ring packet is being transacted on
 * @rx_desc: pointer to the EOP Rx descriptor
 * @skb: pointer to current skb being populated
 * @ptype: the packet type decoded by hardware
 *
 * This function checks the ring, descriptor, and packet information in
 * order to populate the hash, checksum, VLAN, protocol, and
 * other fields within the skb.
 */
void
ice_process_skb_fields(struct ice_rx_ring *rx_ring,
		       union ice_32b_rx_flex_desc *rx_desc,
		       struct sk_buff *skb, u16 ptype)
{
	ice_rx_hash(rx_ring, rx_desc, skb, ptype);

	/* modifies the skb - consumes the enet header */
	skb->protocol = eth_type_trans(skb, rx_ring->netdev);

	ice_rx_csum(rx_ring, skb, rx_desc, ptype);

	if (rx_ring->ptp_rx)
		ice_ptp_rx_hwtstamp(rx_ring, rx_desc, skb);
}

/**
 * ice_receive_skb - Send a completed packet up the stack
 * @rx_ring: Rx ring in play
 * @skb: packet to send up
 * @vlan_tag: VLAN tag for packet
 *
 * This function sends the completed packet (via. skb) up the stack using
 * gro receive functions (with/without VLAN tag)
 */
void
ice_receive_skb(struct ice_rx_ring *rx_ring, struct sk_buff *skb, u16 vlan_tag)
{
	netdev_features_t features = rx_ring->netdev->features;
	bool non_zero_vlan = !!(vlan_tag & VLAN_VID_MASK);

	if ((features & NETIF_F_HW_VLAN_CTAG_RX) && non_zero_vlan)
		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vlan_tag);
	else if ((features & NETIF_F_HW_VLAN_STAG_RX) && non_zero_vlan)
		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021AD), vlan_tag);

	napi_gro_receive(&rx_ring->q_vector->napi, skb);
}

/**
 * ice_clean_xdp_irq - Reclaim resources after transmit completes on XDP ring
 * @xdp_ring: XDP ring to clean
 */
static void ice_clean_xdp_irq(struct ice_tx_ring *xdp_ring)
{
	unsigned int total_bytes = 0, total_pkts = 0;
	u16 tx_thresh = ICE_RING_QUARTER(xdp_ring);
	u16 ntc = xdp_ring->next_to_clean;
	struct ice_tx_desc *next_dd_desc;
	u16 next_dd = xdp_ring->next_dd;
	struct ice_tx_buf *tx_buf;
	int i;

	next_dd_desc = ICE_TX_DESC(xdp_ring, next_dd);
	if (!(next_dd_desc->cmd_type_offset_bsz &
	    cpu_to_le64(ICE_TX_DESC_DTYPE_DESC_DONE)))
		return;

	for (i = 0; i < tx_thresh; i++) {
		tx_buf = &xdp_ring->tx_buf[ntc];

		total_bytes += tx_buf->bytecount;
		/* normally tx_buf->gso_segs was taken but at this point
		 * it's always 1 for us
		 */
		total_pkts++;

		page_frag_free(tx_buf->raw_buf);
		dma_unmap_single(xdp_ring->dev, dma_unmap_addr(tx_buf, dma),
				 dma_unmap_len(tx_buf, len), DMA_TO_DEVICE);
		dma_unmap_len_set(tx_buf, len, 0);
		tx_buf->raw_buf = NULL;

		ntc++;
		if (ntc >= xdp_ring->count)
			ntc = 0;
	}

	next_dd_desc->cmd_type_offset_bsz = 0;
	xdp_ring->next_dd = xdp_ring->next_dd + tx_thresh;
	if (xdp_ring->next_dd > xdp_ring->count)
		xdp_ring->next_dd = tx_thresh - 1;
	xdp_ring->next_to_clean = ntc;
	ice_update_tx_ring_stats(xdp_ring, total_pkts, total_bytes);
}

/**
 * ice_xmit_xdp_ring - submit single packet to XDP ring for transmission
 * @data: packet data pointer
 * @size: packet data size
 * @xdp_ring: XDP ring for transmission
 */
int ice_xmit_xdp_ring(void *data, u16 size, struct ice_tx_ring *xdp_ring)
{
	u16 tx_thresh = ICE_RING_QUARTER(xdp_ring);
	u16 i = xdp_ring->next_to_use;
	struct ice_tx_desc *tx_desc;
	struct ice_tx_buf *tx_buf;
	dma_addr_t dma;

	if (ICE_DESC_UNUSED(xdp_ring) < tx_thresh)
		ice_clean_xdp_irq(xdp_ring);

	if (!unlikely(ICE_DESC_UNUSED(xdp_ring))) {
		xdp_ring->tx_stats.tx_busy++;
		return ICE_XDP_CONSUMED;
	}

	dma = dma_map_single(xdp_ring->dev, data, size, DMA_TO_DEVICE);
	if (dma_mapping_error(xdp_ring->dev, dma))
		return ICE_XDP_CONSUMED;

	tx_buf = &xdp_ring->tx_buf[i];
	tx_buf->bytecount = size;
	tx_buf->gso_segs = 1;
	tx_buf->raw_buf = data;

	/* record length, and DMA address */
	dma_unmap_len_set(tx_buf, len, size);
	dma_unmap_addr_set(tx_buf, dma, dma);

	tx_desc = ICE_TX_DESC(xdp_ring, i);
	tx_desc->buf_addr = cpu_to_le64(dma);
	tx_desc->cmd_type_offset_bsz = ice_build_ctob(ICE_TX_DESC_CMD_EOP, 0,
						      size, 0);

	xdp_ring->xdp_tx_active++;
	i++;
	if (i == xdp_ring->count) {
		i = 0;
		tx_desc = ICE_TX_DESC(xdp_ring, xdp_ring->next_rs);
		tx_desc->cmd_type_offset_bsz |=
			cpu_to_le64(ICE_TX_DESC_CMD_RS << ICE_TXD_QW1_CMD_S);
		xdp_ring->next_rs = tx_thresh - 1;
	}
	xdp_ring->next_to_use = i;

	if (i > xdp_ring->next_rs) {
		tx_desc = ICE_TX_DESC(xdp_ring, xdp_ring->next_rs);
		tx_desc->cmd_type_offset_bsz |=
			cpu_to_le64(ICE_TX_DESC_CMD_RS << ICE_TXD_QW1_CMD_S);
		xdp_ring->next_rs += tx_thresh;
	}

	return ICE_XDP_TX;
}

/**
 * ice_xmit_xdp_buff - convert an XDP buffer to an XDP frame and send it
 * @xdp: XDP buffer
 * @xdp_ring: XDP Tx ring
 *
 * Returns negative on failure, 0 on success.
 */
int ice_xmit_xdp_buff(struct xdp_buff *xdp, struct ice_tx_ring *xdp_ring)
{
	struct xdp_frame *xdpf = xdp_convert_buff_to_frame(xdp);

	if (unlikely(!xdpf))
		return ICE_XDP_CONSUMED;

	return ice_xmit_xdp_ring(xdpf->data, xdpf->len, xdp_ring);
}

/**
 * ice_finalize_xdp_rx - Bump XDP Tx tail and/or flush redirect map
 * @xdp_ring: XDP ring
 * @xdp_res: Result of the receive batch
 *
 * This function bumps XDP Tx tail and/or flush redirect map, and
 * should be called when a batch of packets has been processed in the
 * napi loop.
 */
void ice_finalize_xdp_rx(struct ice_tx_ring *xdp_ring, unsigned int xdp_res)
{
	if (xdp_res & ICE_XDP_REDIR)
		xdp_do_flush_map();

	if (xdp_res & ICE_XDP_TX) {
		if (static_branch_unlikely(&ice_xdp_locking_key))
			spin_lock(&xdp_ring->tx_lock);
		ice_xdp_ring_update_tail(xdp_ring);
		if (static_branch_unlikely(&ice_xdp_locking_key))
			spin_unlock(&xdp_ring->tx_lock);
	}
}