}
/**
- * t4_eth_xmit - add a packet to an Ethernet Tx queue
+ * cxgb4_eth_xmit - add a packet to an Ethernet Tx queue
* @skb: the packet
* @dev: the egress net device
*
* Add a packet to an SGE Ethernet Tx queue. Runs with softirqs disabled.
*/
-netdev_tx_t t4_eth_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t cxgb4_eth_xmit(struct sk_buff *skb, struct net_device *dev)
{
u32 wr_mid, ctrl0, op;
u64 cntrl, *end, *sgl;
return NETDEV_TX_OK;
}
+/* Constants ... */
+enum {
+ /* Egress Queue sizes, producer and consumer indices are all in units
+ * of Egress Context Units bytes. Note that as far as the hardware is
+ * concerned, the free list is an Egress Queue (the host produces free
+ * buffers which the hardware consumes) and free list entries are
+ * 64-bit PCI DMA addresses.
+ */
+ EQ_UNIT = SGE_EQ_IDXSIZE,
+ FL_PER_EQ_UNIT = EQ_UNIT / sizeof(__be64),
+ TXD_PER_EQ_UNIT = EQ_UNIT / sizeof(__be64),
+
+ T4VF_ETHTXQ_MAX_HDR = (sizeof(struct fw_eth_tx_pkt_vm_wr) +
+ sizeof(struct cpl_tx_pkt_lso_core) +
+ sizeof(struct cpl_tx_pkt_core)) / sizeof(__be64),
+};
+
+/**
+ * t4vf_is_eth_imm - can an Ethernet packet be sent as immediate data?
+ * @skb: the packet
+ *
+ * Returns whether an Ethernet packet is small enough to fit completely as
+ * immediate data.
+ */
+static inline int t4vf_is_eth_imm(const struct sk_buff *skb)
+{
+ /* The VF Driver uses the FW_ETH_TX_PKT_VM_WR firmware Work Request
+ * which does not accommodate immediate data. We could dike out all
+ * of the support code for immediate data but that would tie our hands
+ * too much if we ever want to enhace the firmware. It would also
+ * create more differences between the PF and VF Drivers.
+ */
+ return false;
+}
+
+/**
+ * t4vf_calc_tx_flits - calculate the number of flits for a packet TX WR
+ * @skb: the packet
+ *
+ * Returns the number of flits needed for a TX Work Request for the
+ * given Ethernet packet, including the needed WR and CPL headers.
+ */
+static inline unsigned int t4vf_calc_tx_flits(const struct sk_buff *skb)
+{
+ unsigned int flits;
+
+ /* If the skb is small enough, we can pump it out as a work request
+ * with only immediate data. In that case we just have to have the
+ * TX Packet header plus the skb data in the Work Request.
+ */
+ if (t4vf_is_eth_imm(skb))
+ return DIV_ROUND_UP(skb->len + sizeof(struct cpl_tx_pkt),
+ sizeof(__be64));
+
+ /* Otherwise, we're going to have to construct a Scatter gather list
+ * of the skb body and fragments. We also include the flits necessary
+ * for the TX Packet Work Request and CPL. We always have a firmware
+ * Write Header (incorporated as part of the cpl_tx_pkt_lso and
+ * cpl_tx_pkt structures), followed by either a TX Packet Write CPL
+ * message or, if we're doing a Large Send Offload, an LSO CPL message
+ * with an embedded TX Packet Write CPL message.
+ */
+ flits = sgl_len(skb_shinfo(skb)->nr_frags + 1);
+ if (skb_shinfo(skb)->gso_size)
+ flits += (sizeof(struct fw_eth_tx_pkt_vm_wr) +
+ sizeof(struct cpl_tx_pkt_lso_core) +
+ sizeof(struct cpl_tx_pkt_core)) / sizeof(__be64);
+ else
+ flits += (sizeof(struct fw_eth_tx_pkt_vm_wr) +
+ sizeof(struct cpl_tx_pkt_core)) / sizeof(__be64);
+ return flits;
+}
+
+/**
+ * cxgb4_vf_eth_xmit - add a packet to an Ethernet TX queue
+ * @skb: the packet
+ * @dev: the egress net device
+ *
+ * Add a packet to an SGE Ethernet TX queue. Runs with softirqs disabled.
+ */
+static netdev_tx_t cxgb4_vf_eth_xmit(struct sk_buff *skb,
+ struct net_device *dev)
+{
+ dma_addr_t addr[MAX_SKB_FRAGS + 1];
+ const struct skb_shared_info *ssi;
+ struct fw_eth_tx_pkt_vm_wr *wr;
+ int qidx, credits, max_pkt_len;
+ struct cpl_tx_pkt_core *cpl;
+ const struct port_info *pi;
+ unsigned int flits, ndesc;
+ struct sge_eth_txq *txq;
+ struct adapter *adapter;
+ u64 cntrl, *end;
+ u32 wr_mid;
+ const size_t fw_hdr_copy_len = sizeof(wr->ethmacdst) +
+ sizeof(wr->ethmacsrc) +
+ sizeof(wr->ethtype) +
+ sizeof(wr->vlantci);
+
+ /* The chip minimum packet length is 10 octets but the firmware
+ * command that we are using requires that we copy the Ethernet header
+ * (including the VLAN tag) into the header so we reject anything
+ * smaller than that ...
+ */
+ if (unlikely(skb->len < fw_hdr_copy_len))
+ goto out_free;
+
+ /* Discard the packet if the length is greater than mtu */
+ max_pkt_len = ETH_HLEN + dev->mtu;
+ if (skb_vlan_tag_present(skb))
+ max_pkt_len += VLAN_HLEN;
+ if (!skb_shinfo(skb)->gso_size && (unlikely(skb->len > max_pkt_len)))
+ goto out_free;
+
+ /* Figure out which TX Queue we're going to use. */
+ pi = netdev_priv(dev);
+ adapter = pi->adapter;
+ qidx = skb_get_queue_mapping(skb);
+ WARN_ON(qidx >= pi->nqsets);
+ txq = &adapter->sge.ethtxq[pi->first_qset + qidx];
+
+ /* Take this opportunity to reclaim any TX Descriptors whose DMA
+ * transfers have completed.
+ */
+ cxgb4_reclaim_completed_tx(adapter, &txq->q, true);
+
+ /* Calculate the number of flits and TX Descriptors we're going to
+ * need along with how many TX Descriptors will be left over after
+ * we inject our Work Request.
+ */
+ flits = t4vf_calc_tx_flits(skb);
+ ndesc = flits_to_desc(flits);
+ credits = txq_avail(&txq->q) - ndesc;
+
+ if (unlikely(credits < 0)) {
+ /* Not enough room for this packet's Work Request. Stop the
+ * TX Queue and return a "busy" condition. The queue will get
+ * started later on when the firmware informs us that space
+ * has opened up.
+ */
+ eth_txq_stop(txq);
+ dev_err(adapter->pdev_dev,
+ "%s: TX ring %u full while queue awake!\n",
+ dev->name, qidx);
+ return NETDEV_TX_BUSY;
+ }
+
+ if (!t4vf_is_eth_imm(skb) &&
+ unlikely(cxgb4_map_skb(adapter->pdev_dev, skb, addr) < 0)) {
+ /* We need to map the skb into PCI DMA space (because it can't
+ * be in-lined directly into the Work Request) and the mapping
+ * operation failed. Record the error and drop the packet.
+ */
+ txq->mapping_err++;
+ goto out_free;
+ }
+
+ wr_mid = FW_WR_LEN16_V(DIV_ROUND_UP(flits, 2));
+ if (unlikely(credits < ETHTXQ_STOP_THRES)) {
+ /* After we're done injecting the Work Request for this
+ * packet, we'll be below our "stop threshold" so stop the TX
+ * Queue now and schedule a request for an SGE Egress Queue
+ * Update message. The queue will get started later on when
+ * the firmware processes this Work Request and sends us an
+ * Egress Queue Status Update message indicating that space
+ * has opened up.
+ */
+ eth_txq_stop(txq);
+ wr_mid |= FW_WR_EQUEQ_F | FW_WR_EQUIQ_F;
+ }
+
+ /* Start filling in our Work Request. Note that we do _not_ handle
+ * the WR Header wrapping around the TX Descriptor Ring. If our
+ * maximum header size ever exceeds one TX Descriptor, we'll need to
+ * do something else here.
+ */
+ WARN_ON(DIV_ROUND_UP(T4VF_ETHTXQ_MAX_HDR, TXD_PER_EQ_UNIT) > 1);
+ wr = (void *)&txq->q.desc[txq->q.pidx];
+ wr->equiq_to_len16 = cpu_to_be32(wr_mid);
+ wr->r3[0] = cpu_to_be32(0);
+ wr->r3[1] = cpu_to_be32(0);
+ skb_copy_from_linear_data(skb, (void *)wr->ethmacdst, fw_hdr_copy_len);
+ end = (u64 *)wr + flits;
+
+ /* If this is a Large Send Offload packet we'll put in an LSO CPL
+ * message with an encapsulated TX Packet CPL message. Otherwise we
+ * just use a TX Packet CPL message.
+ */
+ ssi = skb_shinfo(skb);
+ if (ssi->gso_size) {
+ struct cpl_tx_pkt_lso_core *lso = (void *)(wr + 1);
+ bool v6 = (ssi->gso_type & SKB_GSO_TCPV6) != 0;
+ int l3hdr_len = skb_network_header_len(skb);
+ int eth_xtra_len = skb_network_offset(skb) - ETH_HLEN;
+
+ wr->op_immdlen =
+ cpu_to_be32(FW_WR_OP_V(FW_ETH_TX_PKT_VM_WR) |
+ FW_WR_IMMDLEN_V(sizeof(*lso) +
+ sizeof(*cpl)));
+ /* Fill in the LSO CPL message. */
+ lso->lso_ctrl =
+ cpu_to_be32(LSO_OPCODE_V(CPL_TX_PKT_LSO) |
+ LSO_FIRST_SLICE_F |
+ LSO_LAST_SLICE_F |
+ LSO_IPV6_V(v6) |
+ LSO_ETHHDR_LEN_V(eth_xtra_len / 4) |
+ LSO_IPHDR_LEN_V(l3hdr_len / 4) |
+ LSO_TCPHDR_LEN_V(tcp_hdr(skb)->doff));
+ lso->ipid_ofst = cpu_to_be16(0);
+ lso->mss = cpu_to_be16(ssi->gso_size);
+ lso->seqno_offset = cpu_to_be32(0);
+ if (is_t4(adapter->params.chip))
+ lso->len = cpu_to_be32(skb->len);
+ else
+ lso->len = cpu_to_be32(LSO_T5_XFER_SIZE_V(skb->len));
+
+ /* Set up TX Packet CPL pointer, control word and perform
+ * accounting.
+ */
+ cpl = (void *)(lso + 1);
+
+ if (CHELSIO_CHIP_VERSION(adapter->params.chip) <= CHELSIO_T5)
+ cntrl = TXPKT_ETHHDR_LEN_V(eth_xtra_len);
+ else
+ cntrl = T6_TXPKT_ETHHDR_LEN_V(eth_xtra_len);
+
+ cntrl |= TXPKT_CSUM_TYPE_V(v6 ?
+ TX_CSUM_TCPIP6 : TX_CSUM_TCPIP) |
+ TXPKT_IPHDR_LEN_V(l3hdr_len);
+ txq->tso++;
+ txq->tx_cso += ssi->gso_segs;
+ } else {
+ int len;
+
+ len = (t4vf_is_eth_imm(skb)
+ ? skb->len + sizeof(*cpl)
+ : sizeof(*cpl));
+ wr->op_immdlen =
+ cpu_to_be32(FW_WR_OP_V(FW_ETH_TX_PKT_VM_WR) |
+ FW_WR_IMMDLEN_V(len));
+
+ /* Set up TX Packet CPL pointer, control word and perform
+ * accounting.
+ */
+ cpl = (void *)(wr + 1);
+ if (skb->ip_summed == CHECKSUM_PARTIAL) {
+ cntrl = hwcsum(adapter->params.chip, skb) |
+ TXPKT_IPCSUM_DIS_F;
+ txq->tx_cso++;
+ } else {
+ cntrl = TXPKT_L4CSUM_DIS_F | TXPKT_IPCSUM_DIS_F;
+ }
+ }
+
+ /* If there's a VLAN tag present, add that to the list of things to
+ * do in this Work Request.
+ */
+ if (skb_vlan_tag_present(skb)) {
+ txq->vlan_ins++;
+ cntrl |= TXPKT_VLAN_VLD_F | TXPKT_VLAN_V(skb_vlan_tag_get(skb));
+ }
+
+ /* Fill in the TX Packet CPL message header. */
+ cpl->ctrl0 = cpu_to_be32(TXPKT_OPCODE_V(CPL_TX_PKT_XT) |
+ TXPKT_INTF_V(pi->port_id) |
+ TXPKT_PF_V(0));
+ cpl->pack = cpu_to_be16(0);
+ cpl->len = cpu_to_be16(skb->len);
+ cpl->ctrl1 = cpu_to_be64(cntrl);
+
+ /* Fill in the body of the TX Packet CPL message with either in-lined
+ * data or a Scatter/Gather List.
+ */
+ if (t4vf_is_eth_imm(skb)) {
+ /* In-line the packet's data and free the skb since we don't
+ * need it any longer.
+ */
+ cxgb4_inline_tx_skb(skb, &txq->q, cpl + 1);
+ dev_consume_skb_any(skb);
+ } else {
+ /* Write the skb's Scatter/Gather list into the TX Packet CPL
+ * message and retain a pointer to the skb so we can free it
+ * later when its DMA completes. (We store the skb pointer
+ * in the Software Descriptor corresponding to the last TX
+ * Descriptor used by the Work Request.)
+ *
+ * The retained skb will be freed when the corresponding TX
+ * Descriptors are reclaimed after their DMAs complete.
+ * However, this could take quite a while since, in general,
+ * the hardware is set up to be lazy about sending DMA
+ * completion notifications to us and we mostly perform TX
+ * reclaims in the transmit routine.
+ *
+ * This is good for performamce but means that we rely on new
+ * TX packets arriving to run the destructors of completed
+ * packets, which open up space in their sockets' send queues.
+ * Sometimes we do not get such new packets causing TX to
+ * stall. A single UDP transmitter is a good example of this
+ * situation. We have a clean up timer that periodically
+ * reclaims completed packets but it doesn't run often enough
+ * (nor do we want it to) to prevent lengthy stalls. A
+ * solution to this problem is to run the destructor early,
+ * after the packet is queued but before it's DMAd. A con is
+ * that we lie to socket memory accounting, but the amount of
+ * extra memory is reasonable (limited by the number of TX
+ * descriptors), the packets do actually get freed quickly by
+ * new packets almost always, and for protocols like TCP that
+ * wait for acks to really free up the data the extra memory
+ * is even less. On the positive side we run the destructors
+ * on the sending CPU rather than on a potentially different
+ * completing CPU, usually a good thing.
+ *
+ * Run the destructor before telling the DMA engine about the
+ * packet to make sure it doesn't complete and get freed
+ * prematurely.
+ */
+ struct ulptx_sgl *sgl = (struct ulptx_sgl *)(cpl + 1);
+ struct sge_txq *tq = &txq->q;
+ int last_desc;
+
+ /* If the Work Request header was an exact multiple of our TX
+ * Descriptor length, then it's possible that the starting SGL
+ * pointer lines up exactly with the end of our TX Descriptor
+ * ring. If that's the case, wrap around to the beginning
+ * here ...
+ */
+ if (unlikely((void *)sgl == (void *)tq->stat)) {
+ sgl = (void *)tq->desc;
+ end = (void *)((void *)tq->desc +
+ ((void *)end - (void *)tq->stat));
+ }
+
+ cxgb4_write_sgl(skb, tq, sgl, end, 0, addr);
+ skb_orphan(skb);
+
+ last_desc = tq->pidx + ndesc - 1;
+ if (last_desc >= tq->size)
+ last_desc -= tq->size;
+ tq->sdesc[last_desc].skb = skb;
+ tq->sdesc[last_desc].sgl = sgl;
+ }
+
+ /* Advance our internal TX Queue state, tell the hardware about
+ * the new TX descriptors and return success.
+ */
+ txq_advance(&txq->q, ndesc);
+
+ cxgb4_ring_tx_db(adapter, &txq->q, ndesc);
+ return NETDEV_TX_OK;
+
+out_free:
+ /* An error of some sort happened. Free the TX skb and tell the
+ * OS that we've "dealt" with the packet ...
+ */
+ dev_kfree_skb_any(skb);
+ return NETDEV_TX_OK;
+}
+
+netdev_tx_t t4_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+ struct port_info *pi = netdev_priv(dev);
+
+ if (unlikely(pi->eth_flags & PRIV_FLAG_PORT_TX_VM))
+ return cxgb4_vf_eth_xmit(skb, dev);
+
+ return cxgb4_eth_xmit(skb, dev);
+}
+
/**
* reclaim_completed_tx_imm - reclaim completed control-queue Tx descs
* @q: the SGE control Tx queue
projects / linux.git / commitdiff