1 files changed, 925 insertions, 0 deletions

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
new file mode 100644
index 000000000000..ab6663d94f42
--- /dev/null
+++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
@@ -0,0 +1,925 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2017 - 2019 Pensando Systems, Inc */
+
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/if_vlan.h>
+#include <net/ip6_checksum.h>
+
+#include "ionic.h"
+#include "ionic_lif.h"
+#include "ionic_txrx.h"
+
+static void ionic_rx_clean(struct ionic_queue *q, struct ionic_desc_info *desc_info,
+			   struct ionic_cq_info *cq_info, void *cb_arg);
+
+static inline void ionic_txq_post(struct ionic_queue *q, bool ring_dbell,
+				  ionic_desc_cb cb_func, void *cb_arg)
+{
+	DEBUG_STATS_TXQ_POST(q_to_qcq(q), q->head->desc, ring_dbell);
+
+	ionic_q_post(q, ring_dbell, cb_func, cb_arg);
+}
+
+static inline void ionic_rxq_post(struct ionic_queue *q, bool ring_dbell,
+				  ionic_desc_cb cb_func, void *cb_arg)
+{
+	ionic_q_post(q, ring_dbell, cb_func, cb_arg);
+
+	DEBUG_STATS_RX_BUFF_CNT(q_to_qcq(q));
+}
+
+static inline struct netdev_queue *q_to_ndq(struct ionic_queue *q)
+{
+	return netdev_get_tx_queue(q->lif->netdev, q->index);
+}
+
+static void ionic_rx_recycle(struct ionic_queue *q, struct ionic_desc_info *desc_info,
+			     struct sk_buff *skb)
+{
+	struct ionic_rxq_desc *old = desc_info->desc;
+	struct ionic_rxq_desc *new = q->head->desc;
+
+	new->addr = old->addr;
+	new->len = old->len;
+
+	ionic_rxq_post(q, true, ionic_rx_clean, skb);
+}
+
+static bool ionic_rx_copybreak(struct ionic_queue *q, struct ionic_desc_info *desc_info,
+			       struct ionic_cq_info *cq_info, struct sk_buff **skb)
+{
+	struct ionic_rxq_comp *comp = cq_info->cq_desc;
+	struct ionic_rxq_desc *desc = desc_info->desc;
+	struct net_device *netdev = q->lif->netdev;
+	struct device *dev = q->lif->ionic->dev;
+	struct sk_buff *new_skb;
+	u16 clen, dlen;
+
+	clen = le16_to_cpu(comp->len);
+	dlen = le16_to_cpu(desc->len);
+	if (clen > q->lif->rx_copybreak) {
+		dma_unmap_single(dev, (dma_addr_t)le64_to_cpu(desc->addr),
+				 dlen, DMA_FROM_DEVICE);
+		return false;
+	}
+
+	new_skb = netdev_alloc_skb_ip_align(netdev, clen);
+	if (!new_skb) {
+		dma_unmap_single(dev, (dma_addr_t)le64_to_cpu(desc->addr),
+				 dlen, DMA_FROM_DEVICE);
+		return false;
+	}
+
+	dma_sync_single_for_cpu(dev, (dma_addr_t)le64_to_cpu(desc->addr),
+				clen, DMA_FROM_DEVICE);
+
+	memcpy(new_skb->data, (*skb)->data, clen);
+
+	ionic_rx_recycle(q, desc_info, *skb);
+	*skb = new_skb;
+
+	return true;
+}
+
+static void ionic_rx_clean(struct ionic_queue *q, struct ionic_desc_info *desc_info,
+			   struct ionic_cq_info *cq_info, void *cb_arg)
+{
+	struct ionic_rxq_comp *comp = cq_info->cq_desc;
+	struct ionic_qcq *qcq = q_to_qcq(q);
+	struct sk_buff *skb = cb_arg;
+	struct ionic_rx_stats *stats;
+	struct net_device *netdev;
+
+	stats = q_to_rx_stats(q);
+	netdev = q->lif->netdev;
+
+	if (comp->status) {
+		ionic_rx_recycle(q, desc_info, skb);
+		return;
+	}
+
+	if (unlikely(test_bit(IONIC_LIF_QUEUE_RESET, q->lif->state))) {
+		/* no packet processing while resetting */
+		ionic_rx_recycle(q, desc_info, skb);
+		return;
+	}
+
+	stats->pkts++;
+	stats->bytes += le16_to_cpu(comp->len);
+
+	ionic_rx_copybreak(q, desc_info, cq_info, &skb);
+
+	skb_put(skb, le16_to_cpu(comp->len));
+	skb->protocol = eth_type_trans(skb, netdev);
+
+	skb_record_rx_queue(skb, q->index);
+
+	if (netdev->features & NETIF_F_RXHASH) {
+		switch (comp->pkt_type_color & IONIC_RXQ_COMP_PKT_TYPE_MASK) {
+		case IONIC_PKT_TYPE_IPV4:
+		case IONIC_PKT_TYPE_IPV6:
+			skb_set_hash(skb, le32_to_cpu(comp->rss_hash),
+				     PKT_HASH_TYPE_L3);
+			break;
+		case IONIC_PKT_TYPE_IPV4_TCP:
+		case IONIC_PKT_TYPE_IPV6_TCP:
+		case IONIC_PKT_TYPE_IPV4_UDP:
+		case IONIC_PKT_TYPE_IPV6_UDP:
+			skb_set_hash(skb, le32_to_cpu(comp->rss_hash),
+				     PKT_HASH_TYPE_L4);
+			break;
+		}
+	}
+
+	if (netdev->features & NETIF_F_RXCSUM) {
+		if (comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_CALC) {
+			skb->ip_summed = CHECKSUM_COMPLETE;
+			skb->csum = (__wsum)le16_to_cpu(comp->csum);
+			stats->csum_complete++;
+		}
+	} else {
+		stats->csum_none++;
+	}
+
+	if ((comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_TCP_BAD) ||
+	    (comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_UDP_BAD) ||
+	    (comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_IP_BAD))
+		stats->csum_error++;
+
+	if (netdev->features & NETIF_F_HW_VLAN_CTAG_RX) {
+		if (comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_VLAN)
+			__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
+					       le16_to_cpu(comp->vlan_tci));
+	}
+
+	napi_gro_receive(&qcq->napi, skb);
+}
+
+static bool ionic_rx_service(struct ionic_cq *cq, struct ionic_cq_info *cq_info)
+{
+	struct ionic_rxq_comp *comp = cq_info->cq_desc;
+	struct ionic_queue *q = cq->bound_q;
+	struct ionic_desc_info *desc_info;
+
+	if (!color_match(comp->pkt_type_color, cq->done_color))
+		return false;
+
+	/* check for empty queue */
+	if (q->tail->index == q->head->index)
+		return false;
+
+	desc_info = q->tail;
+	if (desc_info->index != le16_to_cpu(comp->comp_index))
+		return false;
+
+	q->tail = desc_info->next;
+
+	/* clean the related q entry, only one per qc completion */
+	ionic_rx_clean(q, desc_info, cq_info, desc_info->cb_arg);
+
+	desc_info->cb = NULL;
+	desc_info->cb_arg = NULL;
+
+	return true;
+}
+
+static u32 ionic_rx_walk_cq(struct ionic_cq *rxcq, u32 limit)
+{
+	u32 work_done = 0;
+
+	while (ionic_rx_service(rxcq, rxcq->tail)) {
+		if (rxcq->tail->last)
+			rxcq->done_color = !rxcq->done_color;
+		rxcq->tail = rxcq->tail->next;
+		DEBUG_STATS_CQE_CNT(rxcq);
+
+		if (++work_done >= limit)
+			break;
+	}
+
+	return work_done;
+}
+
+void ionic_rx_flush(struct ionic_cq *cq)
+{
+	struct ionic_dev *idev = &cq->lif->ionic->idev;
+	u32 work_done;
+
+	work_done = ionic_rx_walk_cq(cq, cq->num_descs);
+
+	if (work_done)
+		ionic_intr_credits(idev->intr_ctrl, cq->bound_intr->index,
+				   work_done, IONIC_INTR_CRED_RESET_COALESCE);
+}
+
+static struct sk_buff *ionic_rx_skb_alloc(struct ionic_queue *q, unsigned int len,
+					  dma_addr_t *dma_addr)
+{
+	struct ionic_lif *lif = q->lif;
+	struct ionic_rx_stats *stats;
+	struct net_device *netdev;
+	struct sk_buff *skb;
+	struct device *dev;
+
+	netdev = lif->netdev;
+	dev = lif->ionic->dev;
+	stats = q_to_rx_stats(q);
+	skb = netdev_alloc_skb_ip_align(netdev, len);
+	if (!skb) {
+		net_warn_ratelimited("%s: SKB alloc failed on %s!\n",
+				     netdev->name, q->name);
+		stats->alloc_err++;
+		return NULL;
+	}
+
+	*dma_addr = dma_map_single(dev, skb->data, len, DMA_FROM_DEVICE);
+	if (dma_mapping_error(dev, *dma_addr)) {
+		dev_kfree_skb(skb);
+		net_warn_ratelimited("%s: DMA single map failed on %s!\n",
+				     netdev->name, q->name);
+		stats->dma_map_err++;
+		return NULL;
+	}
+
+	return skb;
+}
+
+#define IONIC_RX_RING_DOORBELL_STRIDE		((1 << 2) - 1)
+
+void ionic_rx_fill(struct ionic_queue *q)
+{
+	struct net_device *netdev = q->lif->netdev;
+	struct ionic_rxq_desc *desc;
+	struct sk_buff *skb;
+	dma_addr_t dma_addr;
+	bool ring_doorbell;
+	unsigned int len;
+	unsigned int i;
+
+	len = netdev->mtu + ETH_HLEN;
+
+	for (i = ionic_q_space_avail(q); i; i--) {
+		skb = ionic_rx_skb_alloc(q, len, &dma_addr);
+		if (!skb)
+			return;
+
+		desc = q->head->desc;
+		desc->addr = cpu_to_le64(dma_addr);
+		desc->len = cpu_to_le16(len);
+		desc->opcode = IONIC_RXQ_DESC_OPCODE_SIMPLE;
+
+		ring_doorbell = ((q->head->index + 1) &
+				IONIC_RX_RING_DOORBELL_STRIDE) == 0;
+
+		ionic_rxq_post(q, ring_doorbell, ionic_rx_clean, skb);
+	}
+}
+
+static void ionic_rx_fill_cb(void *arg)
+{
+	ionic_rx_fill(arg);
+}
+
+void ionic_rx_empty(struct ionic_queue *q)
+{
+	struct device *dev = q->lif->ionic->dev;
+	struct ionic_desc_info *cur;
+	struct ionic_rxq_desc *desc;
+
+	for (cur = q->tail; cur != q->head; cur = cur->next) {
+		desc = cur->desc;
+		dma_unmap_single(dev, le64_to_cpu(desc->addr),
+				 le16_to_cpu(desc->len), DMA_FROM_DEVICE);
+		dev_kfree_skb(cur->cb_arg);
+		cur->cb_arg = NULL;
+	}
+}
+
+int ionic_rx_napi(struct napi_struct *napi, int budget)
+{
+	struct ionic_qcq *qcq = napi_to_qcq(napi);
+	struct ionic_cq *rxcq = napi_to_cq(napi);
+	unsigned int qi = rxcq->bound_q->index;
+	struct ionic_dev *idev;
+	struct ionic_lif *lif;
+	struct ionic_cq *txcq;
+	u32 work_done = 0;
+	u32 flags = 0;
+
+	lif = rxcq->bound_q->lif;
+	idev = &lif->ionic->idev;
+	txcq = &lif->txqcqs[qi].qcq->cq;
+
+	ionic_tx_flush(txcq);
+
+	work_done = ionic_rx_walk_cq(rxcq, budget);
+
+	if (work_done)
+		ionic_rx_fill_cb(rxcq->bound_q);
+
+	if (work_done < budget && napi_complete_done(napi, work_done)) {
+		flags |= IONIC_INTR_CRED_UNMASK;
+		DEBUG_STATS_INTR_REARM(rxcq->bound_intr);
+	}
+
+	if (work_done || flags) {
+		flags |= IONIC_INTR_CRED_RESET_COALESCE;
+		ionic_intr_credits(idev->intr_ctrl, rxcq->bound_intr->index,
+				   work_done, flags);
+	}
+
+	DEBUG_STATS_NAPI_POLL(qcq, work_done);
+
+	return work_done;
+}
+
+static dma_addr_t ionic_tx_map_single(struct ionic_queue *q, void *data, size_t len)
+{
+	struct ionic_tx_stats *stats = q_to_tx_stats(q);
+	struct device *dev = q->lif->ionic->dev;
+	dma_addr_t dma_addr;
+
+	dma_addr = dma_map_single(dev, data, len, DMA_TO_DEVICE);
+	if (dma_mapping_error(dev, dma_addr)) {
+		net_warn_ratelimited("%s: DMA single map failed on %s!\n",
+				     q->lif->netdev->name, q->name);
+		stats->dma_map_err++;
+		return 0;
+	}
+	return dma_addr;
+}
+
+static dma_addr_t ionic_tx_map_frag(struct ionic_queue *q, const skb_frag_t *frag,
+				    size_t offset, size_t len)
+{
+	struct ionic_tx_stats *stats = q_to_tx_stats(q);
+	struct device *dev = q->lif->ionic->dev;
+	dma_addr_t dma_addr;
+
+	dma_addr = skb_frag_dma_map(dev, frag, offset, len, DMA_TO_DEVICE);
+	if (dma_mapping_error(dev, dma_addr)) {
+		net_warn_ratelimited("%s: DMA frag map failed on %s!\n",
+				     q->lif->netdev->name, q->name);
+		stats->dma_map_err++;
+	}
+	return dma_addr;
+}
+
+static void ionic_tx_clean(struct ionic_queue *q, struct ionic_desc_info *desc_info,
+			   struct ionic_cq_info *cq_info, void *cb_arg)
+{
+	struct ionic_txq_sg_desc *sg_desc = desc_info->sg_desc;
+	struct ionic_txq_sg_elem *elem = sg_desc->elems;
+	struct ionic_tx_stats *stats = q_to_tx_stats(q);
+	struct ionic_txq_desc *desc = desc_info->desc;
+	struct device *dev = q->lif->ionic->dev;
+	u8 opcode, flags, nsge;
+	u16 queue_index;
+	unsigned int i;
+	u64 addr;
+
+	decode_txq_desc_cmd(le64_to_cpu(desc->cmd),
+			    &opcode, &flags, &nsge, &addr);
+
+	/* use unmap_single only if either this is not TSO,
+	 * or this is first descriptor of a TSO
+	 */
+	if (opcode != IONIC_TXQ_DESC_OPCODE_TSO ||
+	    flags & IONIC_TXQ_DESC_FLAG_TSO_SOT)
+		dma_unmap_single(dev, (dma_addr_t)addr,
+				 le16_to_cpu(desc->len), DMA_TO_DEVICE);
+	else
+		dma_unmap_page(dev, (dma_addr_t)addr,
+			       le16_to_cpu(desc->len), DMA_TO_DEVICE);
+
+	for (i = 0; i < nsge; i++, elem++)
+		dma_unmap_page(dev, (dma_addr_t)le64_to_cpu(elem->addr),
+			       le16_to_cpu(elem->len), DMA_TO_DEVICE);
+
+	if (cb_arg) {
+		struct sk_buff *skb = cb_arg;
+		u32 len = skb->len;
+
+		queue_index = skb_get_queue_mapping(skb);
+		if (unlikely(__netif_subqueue_stopped(q->lif->netdev,
+						      queue_index))) {
+			netif_wake_subqueue(q->lif->netdev, queue_index);
+			q->wake++;
+		}
+		dev_kfree_skb_any(skb);
+		stats->clean++;
+		netdev_tx_completed_queue(q_to_ndq(q), 1, len);
+	}
+}
+
+void ionic_tx_flush(struct ionic_cq *cq)
+{
+	struct ionic_txq_comp *comp = cq->tail->cq_desc;
+	struct ionic_dev *idev = &cq->lif->ionic->idev;
+	struct ionic_queue *q = cq->bound_q;
+	struct ionic_desc_info *desc_info;
+	unsigned int work_done = 0;
+
+	/* walk the completed cq entries */
+	while (work_done < cq->num_descs &&
+	       color_match(comp->color, cq->done_color)) {
+
+		/* clean the related q entries, there could be
+		 * several q entries completed for each cq completion
+		 */
+		do {
+			desc_info = q->tail;
+			q->tail = desc_info->next;
+			ionic_tx_clean(q, desc_info, cq->tail,
+				       desc_info->cb_arg);
+			desc_info->cb = NULL;
+			desc_info->cb_arg = NULL;
+		} while (desc_info->index != le16_to_cpu(comp->comp_index));
+
+		if (cq->tail->last)
+			cq->done_color = !cq->done_color;
+
+		cq->tail = cq->tail->next;
+		comp = cq->tail->cq_desc;
+		DEBUG_STATS_CQE_CNT(cq);
+
+		work_done++;
+	}
+
+	if (work_done)
+		ionic_intr_credits(idev->intr_ctrl, cq->bound_intr->index,
+				   work_done, 0);
+}
+
+static int ionic_tx_tcp_inner_pseudo_csum(struct sk_buff *skb)
+{
+	int err;
+
+	err = skb_cow_head(skb, 0);
+	if (err)
+		return err;
+
+	if (skb->protocol == cpu_to_be16(ETH_P_IP)) {
+		inner_ip_hdr(skb)->check = 0;
+		inner_tcp_hdr(skb)->check =
+			~csum_tcpudp_magic(inner_ip_hdr(skb)->saddr,
+					   inner_ip_hdr(skb)->daddr,
+					   0, IPPROTO_TCP, 0);
+	} else if (skb->protocol == cpu_to_be16(ETH_P_IPV6)) {
+		inner_tcp_hdr(skb)->check =
+			~csum_ipv6_magic(&inner_ipv6_hdr(skb)->saddr,
+					 &inner_ipv6_hdr(skb)->daddr,
+					 0, IPPROTO_TCP, 0);
+	}
+
+	return 0;
+}
+
+static int ionic_tx_tcp_pseudo_csum(struct sk_buff *skb)
+{
+	int err;
+
+	err = skb_cow_head(skb, 0);
+	if (err)
+		return err;
+
+	if (skb->protocol == cpu_to_be16(ETH_P_IP)) {
+		ip_hdr(skb)->check = 0;
+		tcp_hdr(skb)->check =
+			~csum_tcpudp_magic(ip_hdr(skb)->saddr,
+					   ip_hdr(skb)->daddr,
+					   0, IPPROTO_TCP, 0);
+	} else if (skb->protocol == cpu_to_be16(ETH_P_IPV6)) {
+		tcp_hdr(skb)->check =
+			~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
+					 &ipv6_hdr(skb)->daddr,
+					 0, IPPROTO_TCP, 0);
+	}
+
+	return 0;
+}
+
+static void ionic_tx_tso_post(struct ionic_queue *q, struct ionic_txq_desc *desc,
+			      struct sk_buff *skb,
+			      dma_addr_t addr, u8 nsge, u16 len,
+			      unsigned int hdrlen, unsigned int mss,
+			      bool outer_csum,
+			      u16 vlan_tci, bool has_vlan,
+			      bool start, bool done)
+{
+	u8 flags = 0;
+	u64 cmd;
+
+	flags |= has_vlan ? IONIC_TXQ_DESC_FLAG_VLAN : 0;
+	flags |= outer_csum ? IONIC_TXQ_DESC_FLAG_ENCAP : 0;
+	flags |= start ? IONIC_TXQ_DESC_FLAG_TSO_SOT : 0;
+	flags |= done ? IONIC_TXQ_DESC_FLAG_TSO_EOT : 0;
+
+	cmd = encode_txq_desc_cmd(IONIC_TXQ_DESC_OPCODE_TSO, flags, nsge, addr);
+	desc->cmd = cpu_to_le64(cmd);
+	desc->len = cpu_to_le16(len);
+	desc->vlan_tci = cpu_to_le16(vlan_tci);
+	desc->hdr_len = cpu_to_le16(hdrlen);
+	desc->mss = cpu_to_le16(mss);
+
+	if (done) {
+		skb_tx_timestamp(skb);
+		netdev_tx_sent_queue(q_to_ndq(q), skb->len);
+		ionic_txq_post(q, !netdev_xmit_more(), ionic_tx_clean, skb);
+	} else {
+		ionic_txq_post(q, false, ionic_tx_clean, NULL);
+	}
+}
+
+static struct ionic_txq_desc *ionic_tx_tso_next(struct ionic_queue *q,
+						struct ionic_txq_sg_elem **elem)
+{
+	struct ionic_txq_sg_desc *sg_desc = q->head->sg_desc;
+	struct ionic_txq_desc *desc = q->head->desc;
+
+	*elem = sg_desc->elems;
+	return desc;
+}
+
+static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
+{
+	struct ionic_tx_stats *stats = q_to_tx_stats(q);
+	struct ionic_desc_info *abort = q->head;
+	struct device *dev = q->lif->ionic->dev;
+	struct ionic_desc_info *rewind = abort;
+	struct ionic_txq_sg_elem *elem;
+	struct ionic_txq_desc *desc;
+	unsigned int frag_left = 0;
+	unsigned int offset = 0;
+	unsigned int len_left;
+	dma_addr_t desc_addr;
+	unsigned int hdrlen;
+	unsigned int nfrags;
+	unsigned int seglen;
+	u64 total_bytes = 0;
+	u64 total_pkts = 0;
+	unsigned int left;
+	unsigned int len;
+	unsigned int mss;
+	skb_frag_t *frag;
+	bool start, done;
+	bool outer_csum;
+	bool has_vlan;
+	u16 desc_len;
+	u8 desc_nsge;
+	u16 vlan_tci;
+	bool encap;
+	int err;
+
+	mss = skb_shinfo(skb)->gso_size;
+	nfrags = skb_shinfo(skb)->nr_frags;
+	len_left = skb->len - skb_headlen(skb);
+	outer_csum = (skb_shinfo(skb)->gso_type & SKB_GSO_GRE_CSUM) ||
+		     (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
+	has_vlan = !!skb_vlan_tag_present(skb);
+	vlan_tci = skb_vlan_tag_get(skb);
+	encap = skb->encapsulation;
+
+	/* Preload inner-most TCP csum field with IP pseudo hdr
+	 * calculated with IP length set to zero.  HW will later
+	 * add in length to each TCP segment resulting from the TSO.
+	 */
+
+	if (encap)
+		err = ionic_tx_tcp_inner_pseudo_csum(skb);
+	else
+		err = ionic_tx_tcp_pseudo_csum(skb);
+	if (err)
+		return err;
+
+	if (encap)
+		hdrlen = skb_inner_transport_header(skb) - skb->data +
+			 inner_tcp_hdrlen(skb);
+	else
+		hdrlen = skb_transport_offset(skb) + tcp_hdrlen(skb);
+
+	seglen = hdrlen + mss;
+	left = skb_headlen(skb);
+
+	desc = ionic_tx_tso_next(q, &elem);
+	start = true;
+
+	/* Chop skb->data up into desc segments */
+
+	while (left > 0) {
+		len = min(seglen, left);
+		frag_left = seglen - len;
+		desc_addr = ionic_tx_map_single(q, skb->data + offset, len);
+		if (dma_mapping_error(dev, desc_addr))
+			goto err_out_abort;
+		desc_len = len;
+		desc_nsge = 0;
+		left -= len;
+		offset += len;
+		if (nfrags > 0 && frag_left > 0)
+			continue;
+		done = (nfrags == 0 && left == 0);
+		ionic_tx_tso_post(q, desc, skb,
+				  desc_addr, desc_nsge, desc_len,
+				  hdrlen, mss,
+				  outer_csum,
+				  vlan_tci, has_vlan,
+				  start, done);
+		total_pkts++;
+		total_bytes += start ? len : len + hdrlen;
+		desc = ionic_tx_tso_next(q, &elem);
+		start = false;
+		seglen = mss;
+	}
+
+	/* Chop skb frags into desc segments */
+
+	for (frag = skb_shinfo(skb)->frags; len_left; frag++) {
+		offset = 0;
+		left = skb_frag_size(frag);
+		len_left -= left;
+		nfrags--;
+		stats->frags++;
+
+		while (left > 0) {
+			if (frag_left > 0) {
+				len = min(frag_left, left);
+				frag_left -= len;
+				elem->addr =
+				    cpu_to_le64(ionic_tx_map_frag(q, frag,
+								  offset, len));
+				if (dma_mapping_error(dev, elem->addr))
+					goto err_out_abort;
+				elem->len = cpu_to_le16(len);
+				elem++;
+				desc_nsge++;
+				left -= len;
+				offset += len;
+				if (nfrags > 0 && frag_left > 0)
+					continue;
+				done = (nfrags == 0 && left == 0);
+				ionic_tx_tso_post(q, desc, skb, desc_addr,
+						  desc_nsge, desc_len,
+						  hdrlen, mss, outer_csum,
+						  vlan_tci, has_vlan,
+						  start, done);
+				total_pkts++;
+				total_bytes += start ? len : len + hdrlen;
+				desc = ionic_tx_tso_next(q, &elem);
+				start = false;
+			} else {
+				len = min(mss, left);
+				frag_left = mss - len;
+				desc_addr = ionic_tx_map_frag(q, frag,
+							      offset, len);
+				if (dma_mapping_error(dev, desc_addr))
+					goto err_out_abort;
+				desc_len = len;
+				desc_nsge = 0;
+				left -= len;
+				offset += len;
+				if (nfrags > 0 && frag_left > 0)
+					continue;
+				done = (nfrags == 0 && left == 0);
+				ionic_tx_tso_post(q, desc, skb, desc_addr,
+						  desc_nsge, desc_len,
+						  hdrlen, mss, outer_csum,
+						  vlan_tci, has_vlan,
+						  start, done);
+				total_pkts++;
+				total_bytes += start ? len : len + hdrlen;
+				desc = ionic_tx_tso_next(q, &elem);
+				start = false;
+			}
+		}
+	}
+
+	stats->pkts += total_pkts;
+	stats->bytes += total_bytes;
+	stats->tso++;
+
+	return 0;
+
+err_out_abort:
+	while (rewind->desc != q->head->desc) {
+		ionic_tx_clean(q, rewind, NULL, NULL);
+		rewind = rewind->next;
+	}
+	q->head = abort;
+
+	return -ENOMEM;
+}
+
+static int ionic_tx_calc_csum(struct ionic_queue *q, struct sk_buff *skb)
+{
+	struct ionic_tx_stats *stats = q_to_tx_stats(q);
+	struct ionic_txq_desc *desc = q->head->desc;
+	struct device *dev = q->lif->ionic->dev;
+	dma_addr_t dma_addr;
+	bool has_vlan;
+	u8 flags = 0;
+	bool encap;
+	u64 cmd;
+
+	has_vlan = !!skb_vlan_tag_present(skb);
+	encap = skb->encapsulation;
+
+	dma_addr = ionic_tx_map_single(q, skb->data, skb_headlen(skb));
+	if (dma_mapping_error(dev, dma_addr))
+		return -ENOMEM;
+
+	flags |= has_vlan ? IONIC_TXQ_DESC_FLAG_VLAN : 0;
+	flags |= encap ? IONIC_TXQ_DESC_FLAG_ENCAP : 0;
+
+	cmd = encode_txq_desc_cmd(IONIC_TXQ_DESC_OPCODE_CSUM_PARTIAL,
+				  flags, skb_shinfo(skb)->nr_frags, dma_addr);
+	desc->cmd = cpu_to_le64(cmd);
+	desc->len = cpu_to_le16(skb_headlen(skb));
+	desc->vlan_tci = cpu_to_le16(skb_vlan_tag_get(skb));
+	desc->csum_start = cpu_to_le16(skb_checksum_start_offset(skb));
+	desc->csum_offset = cpu_to_le16(skb->csum_offset);
+
+	if (skb->csum_not_inet)
+		stats->crc32_csum++;
+	else
+		stats->csum++;
+
+	return 0;
+}
+
+static int ionic_tx_calc_no_csum(struct ionic_queue *q, struct sk_buff *skb)
+{
+	struct ionic_tx_stats *stats = q_to_tx_stats(q);
+	struct ionic_txq_desc *desc = q->head->desc;
+	struct device *dev = q->lif->ionic->dev;
+	dma_addr_t dma_addr;
+	bool has_vlan;
+	u8 flags = 0;
+	bool encap;
+	u64 cmd;
+
+	has_vlan = !!skb_vlan_tag_present(skb);
+	encap = skb->encapsulation;
+
+	dma_addr = ionic_tx_map_single(q, skb->data, skb_headlen(skb));
+	if (dma_mapping_error(dev, dma_addr))
+		return -ENOMEM;
+
+	flags |= has_vlan ? IONIC_TXQ_DESC_FLAG_VLAN : 0;
+	flags |= encap ? IONIC_TXQ_DESC_FLAG_ENCAP : 0;
+
+	cmd = encode_txq_desc_cmd(IONIC_TXQ_DESC_OPCODE_CSUM_NONE,
+				  flags, skb_shinfo(skb)->nr_frags, dma_addr);
+	desc->cmd = cpu_to_le64(cmd);
+	desc->len = cpu_to_le16(skb_headlen(skb));
+	desc->vlan_tci = cpu_to_le16(skb_vlan_tag_get(skb));
+
+	stats->no_csum++;
+
+	return 0;
+}
+
+static int ionic_tx_skb_frags(struct ionic_queue *q, struct sk_buff *skb)
+{
+	struct ionic_txq_sg_desc *sg_desc = q->head->sg_desc;
+	unsigned int len_left = skb->len - skb_headlen(skb);
+	struct ionic_txq_sg_elem *elem = sg_desc->elems;
+	struct ionic_tx_stats *stats = q_to_tx_stats(q);
+	struct device *dev = q->lif->ionic->dev;
+	dma_addr_t dma_addr;
+	skb_frag_t *frag;
+	u16 len;
+
+	for (frag = skb_shinfo(skb)->frags; len_left; frag++, elem++) {
+		len = skb_frag_size(frag);
+		elem->len = cpu_to_le16(len);
+		dma_addr = ionic_tx_map_frag(q, frag, 0, len);
+		if (dma_mapping_error(dev, dma_addr))
+			return -ENOMEM;
+		elem->addr = cpu_to_le64(dma_addr);
+		len_left -= len;
+		stats->frags++;
+	}
+
+	return 0;
+}
+
+static int ionic_tx(struct ionic_queue *q, struct sk_buff *skb)
+{
+	struct ionic_tx_stats *stats = q_to_tx_stats(q);
+	int err;
+
+	/* set up the initial descriptor */
+	if (skb->ip_summed == CHECKSUM_PARTIAL)
+		err = ionic_tx_calc_csum(q, skb);
+	else
+		err = ionic_tx_calc_no_csum(q, skb);
+	if (err)
+		return err;
+
+	/* add frags */
+	err = ionic_tx_skb_frags(q, skb);
+	if (err)
+		return err;
+
+	skb_tx_timestamp(skb);
+	stats->pkts++;
+	stats->bytes += skb->len;
+
+	netdev_tx_sent_queue(q_to_ndq(q), skb->len);
+	ionic_txq_post(q, !netdev_xmit_more(), ionic_tx_clean, skb);
+
+	return 0;
+}
+
+static int ionic_tx_descs_needed(struct ionic_queue *q, struct sk_buff *skb)
+{
+	struct ionic_tx_stats *stats = q_to_tx_stats(q);
+	int err;
+
+	/* If TSO, need roundup(skb->len/mss) descs */
+	if (skb_is_gso(skb))
+		return (skb->len / skb_shinfo(skb)->gso_size) + 1;
+
+	/* If non-TSO, just need 1 desc and nr_frags sg elems */
+	if (skb_shinfo(skb)->nr_frags <= IONIC_TX_MAX_SG_ELEMS)
+		return 1;
+
+	/* Too many frags, so linearize */
+	err = skb_linearize(skb);
+	if (err)
+		return err;
+
+	stats->linearize++;
+
+	/* Need 1 desc and zero sg elems */
+	return 1;
+}
+
+static int ionic_maybe_stop_tx(struct ionic_queue *q, int ndescs)
+{
+	int stopped = 0;
+
+	if (unlikely(!ionic_q_has_space(q, ndescs))) {
+		netif_stop_subqueue(q->lif->netdev, q->index);
+		q->stop++;
+		stopped = 1;
+
+		/* Might race with ionic_tx_clean, check again */
+		smp_rmb();
+		if (ionic_q_has_space(q, ndescs)) {
+			netif_wake_subqueue(q->lif->netdev, q->index);
+			stopped = 0;
+		}
+	}
+
+	return stopped;
+}
+
+netdev_tx_t ionic_start_xmit(struct sk_buff *skb, struct net_device *netdev)
+{
+	u16 queue_index = skb_get_queue_mapping(skb);
+	struct ionic_lif *lif = netdev_priv(netdev);
+	struct ionic_queue *q;
+	int ndescs;
+	int err;
+
+	if (unlikely(!test_bit(IONIC_LIF_UP, lif->state))) {
+		dev_kfree_skb(skb);
+		return NETDEV_TX_OK;
+	}
+
+	if (unlikely(!lif_to_txqcq(lif, queue_index)))
+		queue_index = 0;
+	q = lif_to_txq(lif, queue_index);
+
+	ndescs = ionic_tx_descs_needed(q, skb);
+	if (ndescs < 0)
+		goto err_out_drop;
+
+	if (unlikely(ionic_maybe_stop_tx(q, ndescs)))
+		return NETDEV_TX_BUSY;
+
+	if (skb_is_gso(skb))
+		err = ionic_tx_tso(q, skb);
+	else
+		err = ionic_tx(q, skb);
+
+	if (err)
+		goto err_out_drop;
+
+	/* Stop the queue if there aren't descriptors for the next packet.
+	 * Since our SG lists per descriptor take care of most of the possible
+	 * fragmentation, we don't need to have many descriptors available.
+	 */
+	ionic_maybe_stop_tx(q, 4);
+
+	return NETDEV_TX_OK;
+
+err_out_drop:
+	q->stop++;
+	q->drop++;
+	dev_kfree_skb(skb);
+	return NETDEV_TX_OK;
+}