1// SPDX-License-Identifier: GPL-2.0
   2/* Copyright(c) 2013 - 2018 Intel Corporation. */
   3
   4#include <linux/bitfield.h>
   5#include <linux/net/intel/libie/rx.h>
   6#include <linux/prefetch.h>
   7
   8#include "iavf.h"
   9#include "iavf_trace.h"
  10#include "iavf_prototype.h"
  11
  12static __le64 build_ctob(u32 td_cmd, u32 td_offset, unsigned int size,
  13			 u32 td_tag)
  14{
  15	return cpu_to_le64(IAVF_TX_DESC_DTYPE_DATA |
  16			   ((u64)td_cmd  << IAVF_TXD_QW1_CMD_SHIFT) |
  17			   ((u64)td_offset << IAVF_TXD_QW1_OFFSET_SHIFT) |
  18			   ((u64)size  << IAVF_TXD_QW1_TX_BUF_SZ_SHIFT) |
  19			   ((u64)td_tag  << IAVF_TXD_QW1_L2TAG1_SHIFT));
  20}
  21
  22#define IAVF_TXD_CMD (IAVF_TX_DESC_CMD_EOP | IAVF_TX_DESC_CMD_RS)
  23
  24/**
  25 * iavf_unmap_and_free_tx_resource - Release a Tx buffer
  26 * @ring:      the ring that owns the buffer
  27 * @tx_buffer: the buffer to free
  28 **/
  29static void iavf_unmap_and_free_tx_resource(struct iavf_ring *ring,
  30					    struct iavf_tx_buffer *tx_buffer)
  31{
  32	if (tx_buffer->skb) {
  33		if (tx_buffer->tx_flags & IAVF_TX_FLAGS_FD_SB)
  34			kfree(tx_buffer->raw_buf);
  35		else
  36			dev_kfree_skb_any(tx_buffer->skb);
  37		if (dma_unmap_len(tx_buffer, len))
  38			dma_unmap_single(ring->dev,
  39					 dma_unmap_addr(tx_buffer, dma),
  40					 dma_unmap_len(tx_buffer, len),
  41					 DMA_TO_DEVICE);
  42	} else if (dma_unmap_len(tx_buffer, len)) {
  43		dma_unmap_page(ring->dev,
  44			       dma_unmap_addr(tx_buffer, dma),
  45			       dma_unmap_len(tx_buffer, len),
  46			       DMA_TO_DEVICE);
  47	}
  48
  49	tx_buffer->next_to_watch = NULL;
  50	tx_buffer->skb = NULL;
  51	dma_unmap_len_set(tx_buffer, len, 0);
  52	/* tx_buffer must be completely set up in the transmit path */
  53}
  54
  55/**
  56 * iavf_clean_tx_ring - Free any empty Tx buffers
  57 * @tx_ring: ring to be cleaned
  58 **/
  59static void iavf_clean_tx_ring(struct iavf_ring *tx_ring)
  60{
  61	unsigned long bi_size;
  62	u16 i;
  63
  64	/* ring already cleared, nothing to do */
  65	if (!tx_ring->tx_bi)
  66		return;
  67
  68	/* Free all the Tx ring sk_buffs */
  69	for (i = 0; i < tx_ring->count; i++)
  70		iavf_unmap_and_free_tx_resource(tx_ring, &tx_ring->tx_bi[i]);
  71
  72	bi_size = sizeof(struct iavf_tx_buffer) * tx_ring->count;
  73	memset(tx_ring->tx_bi, 0, bi_size);
  74
  75	/* Zero out the descriptor ring */
  76	memset(tx_ring->desc, 0, tx_ring->size);
  77
  78	tx_ring->next_to_use = 0;
  79	tx_ring->next_to_clean = 0;
  80
  81	if (!tx_ring->netdev)
  82		return;
  83
  84	/* cleanup Tx queue statistics */
  85	netdev_tx_reset_queue(txring_txq(tx_ring));
  86}
  87
  88/**
  89 * iavf_free_tx_resources - Free Tx resources per queue
  90 * @tx_ring: Tx descriptor ring for a specific queue
  91 *
  92 * Free all transmit software resources
  93 **/
  94void iavf_free_tx_resources(struct iavf_ring *tx_ring)
  95{
  96	iavf_clean_tx_ring(tx_ring);
  97	kfree(tx_ring->tx_bi);
  98	tx_ring->tx_bi = NULL;
  99
 100	if (tx_ring->desc) {
 101		dma_free_coherent(tx_ring->dev, tx_ring->size,
 102				  tx_ring->desc, tx_ring->dma);
 103		tx_ring->desc = NULL;
 104	}
 105}
 106
 107/**
 108 * iavf_get_tx_pending - how many Tx descriptors not processed
 109 * @ring: the ring of descriptors
 110 * @in_sw: is tx_pending being checked in SW or HW
 111 *
 112 * Since there is no access to the ring head register
 113 * in XL710, we need to use our local copies
 114 **/
 115static u32 iavf_get_tx_pending(struct iavf_ring *ring, bool in_sw)
 116{
 117	u32 head, tail;
 118
 119	/* underlying hardware might not allow access and/or always return
 120	 * 0 for the head/tail registers so just use the cached values
 121	 */
 122	head = ring->next_to_clean;
 123	tail = ring->next_to_use;
 124
 125	if (head != tail)
 126		return (head < tail) ?
 127			tail - head : (tail + ring->count - head);
 128
 129	return 0;
 130}
 131
 132/**
 133 * iavf_force_wb - Issue SW Interrupt so HW does a wb
 134 * @vsi: the VSI we care about
 135 * @q_vector: the vector on which to force writeback
 136 **/
 137static void iavf_force_wb(struct iavf_vsi *vsi, struct iavf_q_vector *q_vector)
 138{
 139	u32 val = IAVF_VFINT_DYN_CTLN1_INTENA_MASK |
 140		  IAVF_VFINT_DYN_CTLN1_ITR_INDX_MASK | /* set noitr */
 141		  IAVF_VFINT_DYN_CTLN1_SWINT_TRIG_MASK |
 142		  IAVF_VFINT_DYN_CTLN1_SW_ITR_INDX_ENA_MASK
 143		  /* allow 00 to be written to the index */;
 144
 145	wr32(&vsi->back->hw,
 146	     IAVF_VFINT_DYN_CTLN1(q_vector->reg_idx),
 147	     val);
 148}
 149
 150/**
 151 * iavf_detect_recover_hung - Function to detect and recover hung_queues
 152 * @vsi:  pointer to vsi struct with tx queues
 153 *
 154 * VSI has netdev and netdev has TX queues. This function is to check each of
 155 * those TX queues if they are hung, trigger recovery by issuing SW interrupt.
 156 **/
 157void iavf_detect_recover_hung(struct iavf_vsi *vsi)
 158{
 159	struct iavf_ring *tx_ring = NULL;
 160	struct net_device *netdev;
 161	unsigned int i;
 162	int packets;
 163
 164	if (!vsi)
 165		return;
 166
 167	if (test_bit(__IAVF_VSI_DOWN, vsi->state))
 168		return;
 169
 170	netdev = vsi->netdev;
 171	if (!netdev)
 172		return;
 173
 174	if (!netif_carrier_ok(netdev))
 175		return;
 176
 177	for (i = 0; i < vsi->back->num_active_queues; i++) {
 178		tx_ring = &vsi->back->tx_rings[i];
 179		if (tx_ring && tx_ring->desc) {
 180			/* If packet counter has not changed the queue is
 181			 * likely stalled, so force an interrupt for this
 182			 * queue.
 183			 *
 184			 * prev_pkt_ctr would be negative if there was no
 185			 * pending work.
 186			 */
 187			packets = tx_ring->stats.packets & INT_MAX;
 188			if (tx_ring->prev_pkt_ctr == packets) {
 189				iavf_force_wb(vsi, tx_ring->q_vector);
 190				continue;
 191			}
 192
 193			/* Memory barrier between read of packet count and call
 194			 * to iavf_get_tx_pending()
 195			 */
 196			smp_rmb();
 197			tx_ring->prev_pkt_ctr =
 198			  iavf_get_tx_pending(tx_ring, true) ? packets : -1;
 199		}
 200	}
 201}
 202
 203#define WB_STRIDE 4
 204
 205/**
 206 * iavf_clean_tx_irq - Reclaim resources after transmit completes
 207 * @vsi: the VSI we care about
 208 * @tx_ring: Tx ring to clean
 209 * @napi_budget: Used to determine if we are in netpoll
 210 *
 211 * Returns true if there's any budget left (e.g. the clean is finished)
 212 **/
 213static bool iavf_clean_tx_irq(struct iavf_vsi *vsi,
 214			      struct iavf_ring *tx_ring, int napi_budget)
 215{
 216	int i = tx_ring->next_to_clean;
 217	struct iavf_tx_buffer *tx_buf;
 218	struct iavf_tx_desc *tx_desc;
 219	unsigned int total_bytes = 0, total_packets = 0;
 220	unsigned int budget = IAVF_DEFAULT_IRQ_WORK;
 221
 222	tx_buf = &tx_ring->tx_bi[i];
 223	tx_desc = IAVF_TX_DESC(tx_ring, i);
 224	i -= tx_ring->count;
 225
 226	do {
 227		struct iavf_tx_desc *eop_desc = tx_buf->next_to_watch;
 228
 229		/* if next_to_watch is not set then there is no work pending */
 230		if (!eop_desc)
 231			break;
 232
 233		/* prevent any other reads prior to eop_desc */
 234		smp_rmb();
 235
 236		iavf_trace(clean_tx_irq, tx_ring, tx_desc, tx_buf);
 237		/* if the descriptor isn't done, no work yet to do */
 238		if (!(eop_desc->cmd_type_offset_bsz &
 239		      cpu_to_le64(IAVF_TX_DESC_DTYPE_DESC_DONE)))
 240			break;
 241
 242		/* clear next_to_watch to prevent false hangs */
 243		tx_buf->next_to_watch = NULL;
 244
 245		/* update the statistics for this packet */
 246		total_bytes += tx_buf->bytecount;
 247		total_packets += tx_buf->gso_segs;
 248
 249		/* free the skb */
 250		napi_consume_skb(tx_buf->skb, napi_budget);
 251
 252		/* unmap skb header data */
 253		dma_unmap_single(tx_ring->dev,
 254				 dma_unmap_addr(tx_buf, dma),
 255				 dma_unmap_len(tx_buf, len),
 256				 DMA_TO_DEVICE);
 257
 258		/* clear tx_buffer data */
 259		tx_buf->skb = NULL;
 260		dma_unmap_len_set(tx_buf, len, 0);
 261
 262		/* unmap remaining buffers */
 263		while (tx_desc != eop_desc) {
 264			iavf_trace(clean_tx_irq_unmap,
 265				   tx_ring, tx_desc, tx_buf);
 266
 267			tx_buf++;
 268			tx_desc++;
 269			i++;
 270			if (unlikely(!i)) {
 271				i -= tx_ring->count;
 272				tx_buf = tx_ring->tx_bi;
 273				tx_desc = IAVF_TX_DESC(tx_ring, 0);
 274			}
 275
 276			/* unmap any remaining paged data */
 277			if (dma_unmap_len(tx_buf, len)) {
 278				dma_unmap_page(tx_ring->dev,
 279					       dma_unmap_addr(tx_buf, dma),
 280					       dma_unmap_len(tx_buf, len),
 281					       DMA_TO_DEVICE);
 282				dma_unmap_len_set(tx_buf, len, 0);
 283			}
 284		}
 285
 286		/* move us one more past the eop_desc for start of next pkt */
 287		tx_buf++;
 288		tx_desc++;
 289		i++;
 290		if (unlikely(!i)) {
 291			i -= tx_ring->count;
 292			tx_buf = tx_ring->tx_bi;
 293			tx_desc = IAVF_TX_DESC(tx_ring, 0);
 294		}
 295
 296		prefetch(tx_desc);
 297
 298		/* update budget accounting */
 299		budget--;
 300	} while (likely(budget));
 301
 302	i += tx_ring->count;
 303	tx_ring->next_to_clean = i;
 304	u64_stats_update_begin(&tx_ring->syncp);
 305	tx_ring->stats.bytes += total_bytes;
 306	tx_ring->stats.packets += total_packets;
 307	u64_stats_update_end(&tx_ring->syncp);
 308	tx_ring->q_vector->tx.total_bytes += total_bytes;
 309	tx_ring->q_vector->tx.total_packets += total_packets;
 310
 311	if (tx_ring->flags & IAVF_TXR_FLAGS_WB_ON_ITR) {
 312		/* check to see if there are < 4 descriptors
 313		 * waiting to be written back, then kick the hardware to force
 314		 * them to be written back in case we stay in NAPI.
 315		 * In this mode on X722 we do not enable Interrupt.
 316		 */
 317		unsigned int j = iavf_get_tx_pending(tx_ring, false);
 318
 319		if (budget &&
 320		    ((j / WB_STRIDE) == 0) && (j > 0) &&
 321		    !test_bit(__IAVF_VSI_DOWN, vsi->state) &&
 322		    (IAVF_DESC_UNUSED(tx_ring) != tx_ring->count))
 323			tx_ring->flags |= IAVF_TXR_FLAGS_ARM_WB;
 324	}
 325
 326	/* notify netdev of completed buffers */
 327	netdev_tx_completed_queue(txring_txq(tx_ring),
 328				  total_packets, total_bytes);
 329
 330#define TX_WAKE_THRESHOLD ((s16)(DESC_NEEDED * 2))
 331	if (unlikely(total_packets && netif_carrier_ok(tx_ring->netdev) &&
 332		     (IAVF_DESC_UNUSED(tx_ring) >= TX_WAKE_THRESHOLD))) {
 333		/* Make sure that anybody stopping the queue after this
 334		 * sees the new next_to_clean.
 335		 */
 336		smp_mb();
 337		if (__netif_subqueue_stopped(tx_ring->netdev,
 338					     tx_ring->queue_index) &&
 339		   !test_bit(__IAVF_VSI_DOWN, vsi->state)) {
 340			netif_wake_subqueue(tx_ring->netdev,
 341					    tx_ring->queue_index);
 342			++tx_ring->tx_stats.restart_queue;
 343		}
 344	}
 345
 346	return !!budget;
 347}
 348
 349/**
 350 * iavf_enable_wb_on_itr - Arm hardware to do a wb, interrupts are not enabled
 351 * @vsi: the VSI we care about
 352 * @q_vector: the vector on which to enable writeback
 353 *
 354 **/
 355static void iavf_enable_wb_on_itr(struct iavf_vsi *vsi,
 356				  struct iavf_q_vector *q_vector)
 357{
 358	u16 flags = q_vector->tx.ring[0].flags;
 359	u32 val;
 360
 361	if (!(flags & IAVF_TXR_FLAGS_WB_ON_ITR))
 362		return;
 363
 364	if (q_vector->arm_wb_state)
 365		return;
 366
 367	val = IAVF_VFINT_DYN_CTLN1_WB_ON_ITR_MASK |
 368	      IAVF_VFINT_DYN_CTLN1_ITR_INDX_MASK; /* set noitr */
 369
 370	wr32(&vsi->back->hw,
 371	     IAVF_VFINT_DYN_CTLN1(q_vector->reg_idx), val);
 372	q_vector->arm_wb_state = true;
 373}
 374
 375static bool iavf_container_is_rx(struct iavf_q_vector *q_vector,
 376				 struct iavf_ring_container *rc)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 377{
 378	return &q_vector->rx == rc;
 379}
 380
 381#define IAVF_AIM_MULTIPLIER_100G	2560
 382#define IAVF_AIM_MULTIPLIER_50G		1280
 383#define IAVF_AIM_MULTIPLIER_40G		1024
 384#define IAVF_AIM_MULTIPLIER_20G		512
 385#define IAVF_AIM_MULTIPLIER_10G		256
 386#define IAVF_AIM_MULTIPLIER_1G		32
 387
 388static unsigned int iavf_mbps_itr_multiplier(u32 speed_mbps)
 389{
 390	switch (speed_mbps) {
 391	case SPEED_100000:
 392		return IAVF_AIM_MULTIPLIER_100G;
 393	case SPEED_50000:
 394		return IAVF_AIM_MULTIPLIER_50G;
 395	case SPEED_40000:
 396		return IAVF_AIM_MULTIPLIER_40G;
 397	case SPEED_25000:
 398	case SPEED_20000:
 399		return IAVF_AIM_MULTIPLIER_20G;
 400	case SPEED_10000:
 401	default:
 402		return IAVF_AIM_MULTIPLIER_10G;
 403	case SPEED_1000:
 404	case SPEED_100:
 405		return IAVF_AIM_MULTIPLIER_1G;
 406	}
 407}
 408
 409static unsigned int
 410iavf_virtchnl_itr_multiplier(enum virtchnl_link_speed speed_virtchnl)
 411{
 412	switch (speed_virtchnl) {
 413	case VIRTCHNL_LINK_SPEED_40GB:
 414		return IAVF_AIM_MULTIPLIER_40G;
 415	case VIRTCHNL_LINK_SPEED_25GB:
 416	case VIRTCHNL_LINK_SPEED_20GB:
 417		return IAVF_AIM_MULTIPLIER_20G;
 418	case VIRTCHNL_LINK_SPEED_10GB:
 419	default:
 420		return IAVF_AIM_MULTIPLIER_10G;
 421	case VIRTCHNL_LINK_SPEED_1GB:
 422	case VIRTCHNL_LINK_SPEED_100MB:
 423		return IAVF_AIM_MULTIPLIER_1G;
 424	}
 425}
 426
 427static unsigned int iavf_itr_divisor(struct iavf_adapter *adapter)
 428{
 429	if (ADV_LINK_SUPPORT(adapter))
 430		return IAVF_ITR_ADAPTIVE_MIN_INC *
 431			iavf_mbps_itr_multiplier(adapter->link_speed_mbps);
 432	else
 433		return IAVF_ITR_ADAPTIVE_MIN_INC *
 434			iavf_virtchnl_itr_multiplier(adapter->link_speed);
 435}
 436
 437/**
 438 * iavf_update_itr - update the dynamic ITR value based on statistics
 439 * @q_vector: structure containing interrupt and ring information
 440 * @rc: structure containing ring performance data
 441 *
 442 * Stores a new ITR value based on packets and byte
 443 * counts during the last interrupt.  The advantage of per interrupt
 444 * computation is faster updates and more accurate ITR for the current
 445 * traffic pattern.  Constants in this function were computed
 446 * based on theoretical maximum wire speed and thresholds were set based
 447 * on testing data as well as attempting to minimize response time
 448 * while increasing bulk throughput.
 449 **/
 450static void iavf_update_itr(struct iavf_q_vector *q_vector,
 451			    struct iavf_ring_container *rc)
 452{
 453	unsigned int avg_wire_size, packets, bytes, itr;
 454	unsigned long next_update = jiffies;
 455
 456	/* If we don't have any rings just leave ourselves set for maximum
 457	 * possible latency so we take ourselves out of the equation.
 458	 */
 459	if (!rc->ring || !ITR_IS_DYNAMIC(rc->ring->itr_setting))
 460		return;
 461
 462	/* For Rx we want to push the delay up and default to low latency.
 463	 * for Tx we want to pull the delay down and default to high latency.
 464	 */
 465	itr = iavf_container_is_rx(q_vector, rc) ?
 466	      IAVF_ITR_ADAPTIVE_MIN_USECS | IAVF_ITR_ADAPTIVE_LATENCY :
 467	      IAVF_ITR_ADAPTIVE_MAX_USECS | IAVF_ITR_ADAPTIVE_LATENCY;
 468
 469	/* If we didn't update within up to 1 - 2 jiffies we can assume
 470	 * that either packets are coming in so slow there hasn't been
 471	 * any work, or that there is so much work that NAPI is dealing
 472	 * with interrupt moderation and we don't need to do anything.
 473	 */
 474	if (time_after(next_update, rc->next_update))
 475		goto clear_counts;
 476
 477	/* If itr_countdown is set it means we programmed an ITR within
 478	 * the last 4 interrupt cycles. This has a side effect of us
 479	 * potentially firing an early interrupt. In order to work around
 480	 * this we need to throw out any data received for a few
 481	 * interrupts following the update.
 482	 */
 483	if (q_vector->itr_countdown) {
 484		itr = rc->target_itr;
 485		goto clear_counts;
 486	}
 487
 488	packets = rc->total_packets;
 489	bytes = rc->total_bytes;
 490
 491	if (iavf_container_is_rx(q_vector, rc)) {
 492		/* If Rx there are 1 to 4 packets and bytes are less than
 493		 * 9000 assume insufficient data to use bulk rate limiting
 494		 * approach unless Tx is already in bulk rate limiting. We
 495		 * are likely latency driven.
 496		 */
 497		if (packets && packets < 4 && bytes < 9000 &&
 498		    (q_vector->tx.target_itr & IAVF_ITR_ADAPTIVE_LATENCY)) {
 499			itr = IAVF_ITR_ADAPTIVE_LATENCY;
 500			goto adjust_by_size;
 501		}
 502	} else if (packets < 4) {
 503		/* If we have Tx and Rx ITR maxed and Tx ITR is running in
 504		 * bulk mode and we are receiving 4 or fewer packets just
 505		 * reset the ITR_ADAPTIVE_LATENCY bit for latency mode so
 506		 * that the Rx can relax.
 507		 */
 508		if (rc->target_itr == IAVF_ITR_ADAPTIVE_MAX_USECS &&
 509		    (q_vector->rx.target_itr & IAVF_ITR_MASK) ==
 510		     IAVF_ITR_ADAPTIVE_MAX_USECS)
 511			goto clear_counts;
 512	} else if (packets > 32) {
 513		/* If we have processed over 32 packets in a single interrupt
 514		 * for Tx assume we need to switch over to "bulk" mode.
 515		 */
 516		rc->target_itr &= ~IAVF_ITR_ADAPTIVE_LATENCY;
 517	}
 518
 519	/* We have no packets to actually measure against. This means
 520	 * either one of the other queues on this vector is active or
 521	 * we are a Tx queue doing TSO with too high of an interrupt rate.
 522	 *
 523	 * Between 4 and 56 we can assume that our current interrupt delay
 524	 * is only slightly too low. As such we should increase it by a small
 525	 * fixed amount.
 526	 */
 527	if (packets < 56) {
 528		itr = rc->target_itr + IAVF_ITR_ADAPTIVE_MIN_INC;
 529		if ((itr & IAVF_ITR_MASK) > IAVF_ITR_ADAPTIVE_MAX_USECS) {
 530			itr &= IAVF_ITR_ADAPTIVE_LATENCY;
 531			itr += IAVF_ITR_ADAPTIVE_MAX_USECS;
 532		}
 533		goto clear_counts;
 534	}
 535
 536	if (packets <= 256) {
 537		itr = min(q_vector->tx.current_itr, q_vector->rx.current_itr);
 538		itr &= IAVF_ITR_MASK;
 539
 540		/* Between 56 and 112 is our "goldilocks" zone where we are
 541		 * working out "just right". Just report that our current
 542		 * ITR is good for us.
 543		 */
 544		if (packets <= 112)
 545			goto clear_counts;
 546
 547		/* If packet count is 128 or greater we are likely looking
 548		 * at a slight overrun of the delay we want. Try halving
 549		 * our delay to see if that will cut the number of packets
 550		 * in half per interrupt.
 551		 */
 552		itr /= 2;
 553		itr &= IAVF_ITR_MASK;
 554		if (itr < IAVF_ITR_ADAPTIVE_MIN_USECS)
 555			itr = IAVF_ITR_ADAPTIVE_MIN_USECS;
 556
 557		goto clear_counts;
 558	}
 559
 560	/* The paths below assume we are dealing with a bulk ITR since
 561	 * number of packets is greater than 256. We are just going to have
 562	 * to compute a value and try to bring the count under control,
 563	 * though for smaller packet sizes there isn't much we can do as
 564	 * NAPI polling will likely be kicking in sooner rather than later.
 565	 */
 566	itr = IAVF_ITR_ADAPTIVE_BULK;
 567
 568adjust_by_size:
 569	/* If packet counts are 256 or greater we can assume we have a gross
 570	 * overestimation of what the rate should be. Instead of trying to fine
 571	 * tune it just use the formula below to try and dial in an exact value
 572	 * give the current packet size of the frame.
 573	 */
 574	avg_wire_size = bytes / packets;
 575
 576	/* The following is a crude approximation of:
 577	 *  wmem_default / (size + overhead) = desired_pkts_per_int
 578	 *  rate / bits_per_byte / (size + ethernet overhead) = pkt_rate
 579	 *  (desired_pkt_rate / pkt_rate) * usecs_per_sec = ITR value
 580	 *
 581	 * Assuming wmem_default is 212992 and overhead is 640 bytes per
 582	 * packet, (256 skb, 64 headroom, 320 shared info), we can reduce the
 583	 * formula down to
 584	 *
 585	 *  (170 * (size + 24)) / (size + 640) = ITR
 586	 *
 587	 * We first do some math on the packet size and then finally bitshift
 588	 * by 8 after rounding up. We also have to account for PCIe link speed
 589	 * difference as ITR scales based on this.
 590	 */
 591	if (avg_wire_size <= 60) {
 592		/* Start at 250k ints/sec */
 593		avg_wire_size = 4096;
 594	} else if (avg_wire_size <= 380) {
 595		/* 250K ints/sec to 60K ints/sec */
 596		avg_wire_size *= 40;
 597		avg_wire_size += 1696;
 598	} else if (avg_wire_size <= 1084) {
 599		/* 60K ints/sec to 36K ints/sec */
 600		avg_wire_size *= 15;
 601		avg_wire_size += 11452;
 602	} else if (avg_wire_size <= 1980) {
 603		/* 36K ints/sec to 30K ints/sec */
 604		avg_wire_size *= 5;
 605		avg_wire_size += 22420;
 606	} else {
 607		/* plateau at a limit of 30K ints/sec */
 608		avg_wire_size = 32256;
 609	}
 610
 611	/* If we are in low latency mode halve our delay which doubles the
 612	 * rate to somewhere between 100K to 16K ints/sec
 613	 */
 614	if (itr & IAVF_ITR_ADAPTIVE_LATENCY)
 615		avg_wire_size /= 2;
 616
 617	/* Resultant value is 256 times larger than it needs to be. This
 618	 * gives us room to adjust the value as needed to either increase
 619	 * or decrease the value based on link speeds of 10G, 2.5G, 1G, etc.
 620	 *
 621	 * Use addition as we have already recorded the new latency flag
 622	 * for the ITR value.
 623	 */
 624	itr += DIV_ROUND_UP(avg_wire_size,
 625			    iavf_itr_divisor(q_vector->adapter)) *
 626		IAVF_ITR_ADAPTIVE_MIN_INC;
 627
 628	if ((itr & IAVF_ITR_MASK) > IAVF_ITR_ADAPTIVE_MAX_USECS) {
 629		itr &= IAVF_ITR_ADAPTIVE_LATENCY;
 630		itr += IAVF_ITR_ADAPTIVE_MAX_USECS;
 631	}
 632
 633clear_counts:
 634	/* write back value */
 635	rc->target_itr = itr;
 636
 637	/* next update should occur within next jiffy */
 638	rc->next_update = next_update + 1;
 639
 640	rc->total_bytes = 0;
 641	rc->total_packets = 0;
 642}
 643
 644/**
 645 * iavf_setup_tx_descriptors - Allocate the Tx descriptors
 646 * @tx_ring: the tx ring to set up
 647 *
 648 * Return 0 on success, negative on error
 649 **/
 650int iavf_setup_tx_descriptors(struct iavf_ring *tx_ring)
 651{
 652	struct device *dev = tx_ring->dev;
 653	int bi_size;
 654
 655	if (!dev)
 656		return -ENOMEM;
 657
 658	/* warn if we are about to overwrite the pointer */
 659	WARN_ON(tx_ring->tx_bi);
 660	bi_size = sizeof(struct iavf_tx_buffer) * tx_ring->count;
 661	tx_ring->tx_bi = kzalloc(bi_size, GFP_KERNEL);
 662	if (!tx_ring->tx_bi)
 663		goto err;
 664
 665	/* round up to nearest 4K */
 666	tx_ring->size = tx_ring->count * sizeof(struct iavf_tx_desc);
 667	tx_ring->size = ALIGN(tx_ring->size, 4096);
 668	tx_ring->desc = dma_alloc_coherent(dev, tx_ring->size,
 669					   &tx_ring->dma, GFP_KERNEL);
 670	if (!tx_ring->desc) {
 671		dev_info(dev, "Unable to allocate memory for the Tx descriptor ring, size=%d\n",
 672			 tx_ring->size);
 673		goto err;
 674	}
 675
 676	tx_ring->next_to_use = 0;
 677	tx_ring->next_to_clean = 0;
 678	tx_ring->prev_pkt_ctr = -1;
 679	return 0;
 680
 681err:
 682	kfree(tx_ring->tx_bi);
 683	tx_ring->tx_bi = NULL;
 684	return -ENOMEM;
 685}
 686
 687/**
 688 * iavf_clean_rx_ring - Free Rx buffers
 689 * @rx_ring: ring to be cleaned
 690 **/
 691static void iavf_clean_rx_ring(struct iavf_ring *rx_ring)
 692{
 
 
 
 693	/* ring already cleared, nothing to do */
 694	if (!rx_ring->rx_fqes)
 695		return;
 696
 697	if (rx_ring->skb) {
 698		dev_kfree_skb(rx_ring->skb);
 699		rx_ring->skb = NULL;
 700	}
 701
 702	/* Free all the Rx ring buffers */
 703	for (u32 i = rx_ring->next_to_clean; i != rx_ring->next_to_use; ) {
 704		const struct libeth_fqe *rx_fqes = &rx_ring->rx_fqes[i];
 705
 706		page_pool_put_full_page(rx_ring->pp, rx_fqes->page, false);
 
 707
 708		if (unlikely(++i == rx_ring->count))
 709			i = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 710	}
 711
 
 
 
 
 
 
 
 712	rx_ring->next_to_clean = 0;
 713	rx_ring->next_to_use = 0;
 714}
 715
 716/**
 717 * iavf_free_rx_resources - Free Rx resources
 718 * @rx_ring: ring to clean the resources from
 719 *
 720 * Free all receive software resources
 721 **/
 722void iavf_free_rx_resources(struct iavf_ring *rx_ring)
 723{
 724	struct libeth_fq fq = {
 725		.fqes	= rx_ring->rx_fqes,
 726		.pp	= rx_ring->pp,
 727	};
 728
 729	iavf_clean_rx_ring(rx_ring);
 
 
 730
 731	if (rx_ring->desc) {
 732		dma_free_coherent(rx_ring->pp->p.dev, rx_ring->size,
 733				  rx_ring->desc, rx_ring->dma);
 734		rx_ring->desc = NULL;
 735	}
 736
 737	libeth_rx_fq_destroy(&fq);
 738	rx_ring->rx_fqes = NULL;
 739	rx_ring->pp = NULL;
 740}
 741
 742/**
 743 * iavf_setup_rx_descriptors - Allocate Rx descriptors
 744 * @rx_ring: Rx descriptor ring (for a specific queue) to setup
 745 *
 746 * Returns 0 on success, negative on failure
 747 **/
 748int iavf_setup_rx_descriptors(struct iavf_ring *rx_ring)
 749{
 750	struct libeth_fq fq = {
 751		.count		= rx_ring->count,
 752		.buf_len	= LIBIE_MAX_RX_BUF_LEN,
 753		.nid		= NUMA_NO_NODE,
 754	};
 755	int ret;
 756
 757	ret = libeth_rx_fq_create(&fq, &rx_ring->q_vector->napi);
 758	if (ret)
 759		return ret;
 760
 761	rx_ring->pp = fq.pp;
 762	rx_ring->rx_fqes = fq.fqes;
 763	rx_ring->truesize = fq.truesize;
 764	rx_ring->rx_buf_len = fq.buf_len;
 765
 766	u64_stats_init(&rx_ring->syncp);
 767
 768	/* Round up to nearest 4K */
 769	rx_ring->size = rx_ring->count * sizeof(union iavf_32byte_rx_desc);
 770	rx_ring->size = ALIGN(rx_ring->size, 4096);
 771	rx_ring->desc = dma_alloc_coherent(fq.pp->p.dev, rx_ring->size,
 772					   &rx_ring->dma, GFP_KERNEL);
 773
 774	if (!rx_ring->desc) {
 775		dev_info(fq.pp->p.dev, "Unable to allocate memory for the Rx descriptor ring, size=%d\n",
 776			 rx_ring->size);
 777		goto err;
 778	}
 779
 
 780	rx_ring->next_to_clean = 0;
 781	rx_ring->next_to_use = 0;
 782
 783	return 0;
 784
 785err:
 786	libeth_rx_fq_destroy(&fq);
 787	rx_ring->rx_fqes = NULL;
 788	rx_ring->pp = NULL;
 789
 790	return -ENOMEM;
 791}
 792
 793/**
 794 * iavf_release_rx_desc - Store the new tail and head values
 795 * @rx_ring: ring to bump
 796 * @val: new head index
 797 **/
 798static void iavf_release_rx_desc(struct iavf_ring *rx_ring, u32 val)
 799{
 800	rx_ring->next_to_use = val;
 801
 
 
 
 802	/* Force memory writes to complete before letting h/w
 803	 * know there are new descriptors to fetch.  (Only
 804	 * applicable for weak-ordered memory model archs,
 805	 * such as IA-64).
 806	 */
 807	wmb();
 808	writel(val, rx_ring->tail);
 809}
 810
 811/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 812 * iavf_receive_skb - Send a completed packet up the stack
 813 * @rx_ring:  rx ring in play
 814 * @skb: packet to send up
 815 * @vlan_tag: vlan tag for packet
 816 **/
 817static void iavf_receive_skb(struct iavf_ring *rx_ring,
 818			     struct sk_buff *skb, u16 vlan_tag)
 819{
 820	struct iavf_q_vector *q_vector = rx_ring->q_vector;
 821
 822	if ((rx_ring->netdev->features & NETIF_F_HW_VLAN_CTAG_RX) &&
 823	    (vlan_tag & VLAN_VID_MASK))
 824		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vlan_tag);
 825	else if ((rx_ring->netdev->features & NETIF_F_HW_VLAN_STAG_RX) &&
 826		 vlan_tag & VLAN_VID_MASK)
 827		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021AD), vlan_tag);
 828
 829	napi_gro_receive(&q_vector->napi, skb);
 830}
 831
 832/**
 833 * iavf_alloc_rx_buffers - Replace used receive buffers
 834 * @rx_ring: ring to place buffers on
 835 * @cleaned_count: number of buffers to replace
 836 *
 837 * Returns false if all allocations were successful, true if any fail
 838 **/
 839bool iavf_alloc_rx_buffers(struct iavf_ring *rx_ring, u16 cleaned_count)
 840{
 841	const struct libeth_fq_fp fq = {
 842		.pp		= rx_ring->pp,
 843		.fqes		= rx_ring->rx_fqes,
 844		.truesize	= rx_ring->truesize,
 845		.count		= rx_ring->count,
 846	};
 847	u16 ntu = rx_ring->next_to_use;
 848	union iavf_rx_desc *rx_desc;
 
 849
 850	/* do nothing if no valid netdev defined */
 851	if (!rx_ring->netdev || !cleaned_count)
 852		return false;
 853
 854	rx_desc = IAVF_RX_DESC(rx_ring, ntu);
 
 855
 856	do {
 857		dma_addr_t addr;
 858
 859		addr = libeth_rx_alloc(&fq, ntu);
 860		if (addr == DMA_MAPPING_ERROR)
 861			goto no_buffers;
 862
 
 
 
 
 
 
 863		/* Refresh the desc even if buffer_addrs didn't change
 864		 * because each write-back erases this info.
 865		 */
 866		rx_desc->read.pkt_addr = cpu_to_le64(addr);
 867
 868		rx_desc++;
 
 869		ntu++;
 870		if (unlikely(ntu == rx_ring->count)) {
 871			rx_desc = IAVF_RX_DESC(rx_ring, 0);
 
 872			ntu = 0;
 873		}
 874
 875		/* clear the status bits for the next_to_use descriptor */
 876		rx_desc->wb.qword1.status_error_len = 0;
 877
 878		cleaned_count--;
 879	} while (cleaned_count);
 880
 881	if (rx_ring->next_to_use != ntu)
 882		iavf_release_rx_desc(rx_ring, ntu);
 883
 884	return false;
 885
 886no_buffers:
 887	if (rx_ring->next_to_use != ntu)
 888		iavf_release_rx_desc(rx_ring, ntu);
 889
 890	rx_ring->rx_stats.alloc_page_failed++;
 891
 892	/* make sure to come back via polling to try again after
 893	 * allocation failure
 894	 */
 895	return true;
 896}
 897
 898/**
 899 * iavf_rx_checksum - Indicate in skb if hw indicated a good cksum
 900 * @vsi: the VSI we care about
 901 * @skb: skb currently being received and modified
 902 * @rx_desc: the receive descriptor
 903 **/
 904static void iavf_rx_checksum(struct iavf_vsi *vsi,
 905			     struct sk_buff *skb,
 906			     union iavf_rx_desc *rx_desc)
 907{
 908	struct libeth_rx_pt decoded;
 909	u32 rx_error, rx_status;
 910	bool ipv4, ipv6;
 911	u8 ptype;
 912	u64 qword;
 913
 
 
 
 
 
 
 
 
 914	skb->ip_summed = CHECKSUM_NONE;
 915
 916	qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
 917	ptype = FIELD_GET(IAVF_RXD_QW1_PTYPE_MASK, qword);
 918
 919	decoded = libie_rx_pt_parse(ptype);
 920	if (!libeth_rx_pt_has_checksum(vsi->netdev, decoded))
 921		return;
 922
 923	rx_error = FIELD_GET(IAVF_RXD_QW1_ERROR_MASK, qword);
 924	rx_status = FIELD_GET(IAVF_RXD_QW1_STATUS_MASK, qword);
 925
 926	/* did the hardware decode the packet and checksum? */
 927	if (!(rx_status & BIT(IAVF_RX_DESC_STATUS_L3L4P_SHIFT)))
 928		return;
 929
 930	ipv4 = libeth_rx_pt_get_ip_ver(decoded) == LIBETH_RX_PT_OUTER_IPV4;
 931	ipv6 = libeth_rx_pt_get_ip_ver(decoded) == LIBETH_RX_PT_OUTER_IPV6;
 
 
 
 
 
 
 932
 933	if (ipv4 &&
 934	    (rx_error & (BIT(IAVF_RX_DESC_ERROR_IPE_SHIFT) |
 935			 BIT(IAVF_RX_DESC_ERROR_EIPE_SHIFT))))
 936		goto checksum_fail;
 937
 938	/* likely incorrect csum if alternate IP extension headers found */
 939	if (ipv6 &&
 940	    rx_status & BIT(IAVF_RX_DESC_STATUS_IPV6EXADD_SHIFT))
 941		/* don't increment checksum err here, non-fatal err */
 942		return;
 943
 944	/* there was some L4 error, count error and punt packet to the stack */
 945	if (rx_error & BIT(IAVF_RX_DESC_ERROR_L4E_SHIFT))
 946		goto checksum_fail;
 947
 948	/* handle packets that were not able to be checksummed due
 949	 * to arrival speed, in this case the stack can compute
 950	 * the csum.
 951	 */
 952	if (rx_error & BIT(IAVF_RX_DESC_ERROR_PPRS_SHIFT))
 953		return;
 954
 955	skb->ip_summed = CHECKSUM_UNNECESSARY;
 
 
 
 
 
 
 
 
 
 
 956	return;
 957
 958checksum_fail:
 959	vsi->back->hw_csum_rx_error++;
 960}
 961
 962/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 963 * iavf_rx_hash - set the hash value in the skb
 964 * @ring: descriptor ring
 965 * @rx_desc: specific descriptor
 966 * @skb: skb currently being received and modified
 967 * @rx_ptype: Rx packet type
 968 **/
 969static void iavf_rx_hash(struct iavf_ring *ring,
 970			 union iavf_rx_desc *rx_desc,
 971			 struct sk_buff *skb,
 972			 u8 rx_ptype)
 973{
 974	struct libeth_rx_pt decoded;
 975	u32 hash;
 976	const __le64 rss_mask =
 977		cpu_to_le64((u64)IAVF_RX_DESC_FLTSTAT_RSS_HASH <<
 978			    IAVF_RX_DESC_STATUS_FLTSTAT_SHIFT);
 979
 980	decoded = libie_rx_pt_parse(rx_ptype);
 981	if (!libeth_rx_pt_has_hash(ring->netdev, decoded))
 982		return;
 983
 984	if ((rx_desc->wb.qword1.status_error_len & rss_mask) == rss_mask) {
 985		hash = le32_to_cpu(rx_desc->wb.qword0.hi_dword.rss);
 986		libeth_rx_pt_set_hash(skb, hash, decoded);
 987	}
 988}
 989
 990/**
 991 * iavf_process_skb_fields - Populate skb header fields from Rx descriptor
 992 * @rx_ring: rx descriptor ring packet is being transacted on
 993 * @rx_desc: pointer to the EOP Rx descriptor
 994 * @skb: pointer to current skb being populated
 995 * @rx_ptype: the packet type decoded by hardware
 996 *
 997 * This function checks the ring, descriptor, and packet information in
 998 * order to populate the hash, checksum, VLAN, protocol, and
 999 * other fields within the skb.
1000 **/
1001static void
1002iavf_process_skb_fields(struct iavf_ring *rx_ring,
1003			union iavf_rx_desc *rx_desc, struct sk_buff *skb,
1004			u8 rx_ptype)
1005{
1006	iavf_rx_hash(rx_ring, rx_desc, skb, rx_ptype);
1007
1008	iavf_rx_checksum(rx_ring->vsi, skb, rx_desc);
1009
1010	skb_record_rx_queue(skb, rx_ring->queue_index);
1011
1012	/* modifies the skb - consumes the enet header */
1013	skb->protocol = eth_type_trans(skb, rx_ring->netdev);
1014}
1015
1016/**
1017 * iavf_cleanup_headers - Correct empty headers
1018 * @rx_ring: rx descriptor ring packet is being transacted on
1019 * @skb: pointer to current skb being fixed
1020 *
1021 * Also address the case where we are pulling data in on pages only
1022 * and as such no data is present in the skb header.
1023 *
1024 * In addition if skb is not at least 60 bytes we need to pad it so that
1025 * it is large enough to qualify as a valid Ethernet frame.
1026 *
1027 * Returns true if an error was encountered and skb was freed.
1028 **/
1029static bool iavf_cleanup_headers(struct iavf_ring *rx_ring, struct sk_buff *skb)
1030{
1031	/* if eth_skb_pad returns an error the skb was freed */
1032	if (eth_skb_pad(skb))
1033		return true;
1034
1035	return false;
1036}
1037
1038/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1039 * iavf_add_rx_frag - Add contents of Rx buffer to sk_buff
1040 * @skb: sk_buff to place the data into
1041 * @rx_buffer: buffer containing page to add
 
1042 * @size: packet length from rx_desc
1043 *
1044 * This function will add the data contained in rx_buffer->page to the skb.
1045 * It will just attach the page as a frag to the skb.
1046 *
1047 * The function will then update the page offset.
1048 **/
1049static void iavf_add_rx_frag(struct sk_buff *skb,
1050			     const struct libeth_fqe *rx_buffer,
 
1051			     unsigned int size)
1052{
1053	u32 hr = rx_buffer->page->pp->p.offset;
 
 
 
 
 
 
 
1054
1055	skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buffer->page,
1056			rx_buffer->offset + hr, size, rx_buffer->truesize);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1057}
1058
1059/**
1060 * iavf_build_skb - Build skb around an existing buffer
 
1061 * @rx_buffer: Rx buffer to pull data from
1062 * @size: size of buffer to add to skb
1063 *
1064 * This function builds an skb around an existing Rx buffer, taking care
1065 * to set up the skb correctly and avoid any memcpy overhead.
1066 */
1067static struct sk_buff *iavf_build_skb(const struct libeth_fqe *rx_buffer,
 
1068				      unsigned int size)
1069{
1070	u32 hr = rx_buffer->page->pp->p.offset;
1071	struct sk_buff *skb;
1072	void *va;
 
 
 
 
 
 
 
1073
 
 
1074	/* prefetch first cache line of first page */
1075	va = page_address(rx_buffer->page) + rx_buffer->offset;
1076	net_prefetch(va + hr);
1077
1078	/* build an skb around the page buffer */
1079	skb = napi_build_skb(va, rx_buffer->truesize);
1080	if (unlikely(!skb))
1081		return NULL;
1082
1083	skb_mark_for_recycle(skb);
1084
1085	/* update pointers within the skb to store the data */
1086	skb_reserve(skb, hr);
1087	__skb_put(skb, size);
1088
 
 
 
 
 
 
 
1089	return skb;
1090}
1091
1092/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1093 * iavf_is_non_eop - process handling of non-EOP buffers
1094 * @rx_ring: Rx ring being processed
1095 * @rx_desc: Rx descriptor for current buffer
1096 * @skb: Current socket buffer containing buffer in progress
1097 *
1098 * This function updates next to clean.  If the buffer is an EOP buffer
1099 * this function exits returning false, otherwise it will place the
1100 * sk_buff in the next buffer to be chained and return true indicating
1101 * that this is in fact a non-EOP buffer.
1102 **/
1103static bool iavf_is_non_eop(struct iavf_ring *rx_ring,
1104			    union iavf_rx_desc *rx_desc,
1105			    struct sk_buff *skb)
1106{
1107	u32 ntc = rx_ring->next_to_clean + 1;
1108
1109	/* fetch, update, and store next to clean */
1110	ntc = (ntc < rx_ring->count) ? ntc : 0;
1111	rx_ring->next_to_clean = ntc;
1112
1113	prefetch(IAVF_RX_DESC(rx_ring, ntc));
1114
1115	/* if we are the last buffer then there is nothing else to do */
1116#define IAVF_RXD_EOF BIT(IAVF_RX_DESC_STATUS_EOF_SHIFT)
1117	if (likely(iavf_test_staterr(rx_desc, IAVF_RXD_EOF)))
1118		return false;
1119
1120	rx_ring->rx_stats.non_eop_descs++;
1121
1122	return true;
1123}
1124
1125/**
1126 * iavf_clean_rx_irq - Clean completed descriptors from Rx ring - bounce buf
1127 * @rx_ring: rx descriptor ring to transact packets on
1128 * @budget: Total limit on number of packets to process
1129 *
1130 * This function provides a "bounce buffer" approach to Rx interrupt
1131 * processing.  The advantage to this is that on systems that have
1132 * expensive overhead for IOMMU access this provides a means of avoiding
1133 * it by maintaining the mapping of the page to the system.
1134 *
1135 * Returns amount of work completed
1136 **/
1137static int iavf_clean_rx_irq(struct iavf_ring *rx_ring, int budget)
1138{
1139	unsigned int total_rx_bytes = 0, total_rx_packets = 0;
1140	struct sk_buff *skb = rx_ring->skb;
1141	u16 cleaned_count = IAVF_DESC_UNUSED(rx_ring);
1142	bool failure = false;
1143
1144	while (likely(total_rx_packets < (unsigned int)budget)) {
1145		struct libeth_fqe *rx_buffer;
1146		union iavf_rx_desc *rx_desc;
1147		unsigned int size;
1148		u16 vlan_tag = 0;
1149		u8 rx_ptype;
1150		u64 qword;
1151
1152		/* return some buffers to hardware, one at a time is too slow */
1153		if (cleaned_count >= IAVF_RX_BUFFER_WRITE) {
1154			failure = failure ||
1155				  iavf_alloc_rx_buffers(rx_ring, cleaned_count);
1156			cleaned_count = 0;
1157		}
1158
1159		rx_desc = IAVF_RX_DESC(rx_ring, rx_ring->next_to_clean);
1160
1161		/* status_error_len will always be zero for unused descriptors
1162		 * because it's cleared in cleanup, and overlaps with hdr_addr
1163		 * which is always zero because packet split isn't used, if the
1164		 * hardware wrote DD then the length will be non-zero
1165		 */
1166		qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
1167
1168		/* This memory barrier is needed to keep us from reading
1169		 * any other fields out of the rx_desc until we have
1170		 * verified the descriptor has been written back.
1171		 */
1172		dma_rmb();
1173#define IAVF_RXD_DD BIT(IAVF_RX_DESC_STATUS_DD_SHIFT)
1174		if (!iavf_test_staterr(rx_desc, IAVF_RXD_DD))
1175			break;
1176
1177		size = FIELD_GET(IAVF_RXD_QW1_LENGTH_PBUF_MASK, qword);
 
1178
1179		iavf_trace(clean_rx_irq, rx_ring, rx_desc, skb);
1180
1181		rx_buffer = &rx_ring->rx_fqes[rx_ring->next_to_clean];
1182		if (!libeth_rx_sync_for_cpu(rx_buffer, size))
1183			goto skip_data;
1184
1185		/* retrieve a buffer from the ring */
1186		if (skb)
1187			iavf_add_rx_frag(skb, rx_buffer, size);
 
 
1188		else
1189			skb = iavf_build_skb(rx_buffer, size);
1190
1191		/* exit if we failed to retrieve a buffer */
1192		if (!skb) {
1193			rx_ring->rx_stats.alloc_buff_failed++;
 
 
1194			break;
1195		}
1196
1197skip_data:
1198		cleaned_count++;
1199
1200		if (iavf_is_non_eop(rx_ring, rx_desc, skb) || unlikely(!skb))
1201			continue;
1202
1203		/* ERR_MASK will only have valid bits if EOP set, and
1204		 * what we are doing here is actually checking
1205		 * IAVF_RX_DESC_ERROR_RXE_SHIFT, since it is the zeroth bit in
1206		 * the error field
1207		 */
1208		if (unlikely(iavf_test_staterr(rx_desc, BIT(IAVF_RXD_QW1_ERROR_SHIFT)))) {
1209			dev_kfree_skb_any(skb);
1210			skb = NULL;
1211			continue;
1212		}
1213
1214		if (iavf_cleanup_headers(rx_ring, skb)) {
1215			skb = NULL;
1216			continue;
1217		}
1218
1219		/* probably a little skewed due to removing CRC */
1220		total_rx_bytes += skb->len;
1221
1222		qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
1223		rx_ptype = FIELD_GET(IAVF_RXD_QW1_PTYPE_MASK, qword);
 
1224
1225		/* populate checksum, VLAN, and protocol */
1226		iavf_process_skb_fields(rx_ring, rx_desc, skb, rx_ptype);
1227
1228		if (qword & BIT(IAVF_RX_DESC_STATUS_L2TAG1P_SHIFT) &&
1229		    rx_ring->flags & IAVF_TXRX_FLAGS_VLAN_TAG_LOC_L2TAG1)
1230			vlan_tag = le16_to_cpu(rx_desc->wb.qword0.lo_dword.l2tag1);
1231		if (rx_desc->wb.qword2.ext_status &
1232		    cpu_to_le16(BIT(IAVF_RX_DESC_EXT_STATUS_L2TAG2P_SHIFT)) &&
1233		    rx_ring->flags & IAVF_RXR_FLAGS_VLAN_TAG_LOC_L2TAG2_2)
1234			vlan_tag = le16_to_cpu(rx_desc->wb.qword2.l2tag2_2);
1235
1236		iavf_trace(clean_rx_irq_rx, rx_ring, rx_desc, skb);
1237		iavf_receive_skb(rx_ring, skb, vlan_tag);
1238		skb = NULL;
1239
1240		/* update budget accounting */
1241		total_rx_packets++;
1242	}
1243
1244	rx_ring->skb = skb;
1245
1246	u64_stats_update_begin(&rx_ring->syncp);
1247	rx_ring->stats.packets += total_rx_packets;
1248	rx_ring->stats.bytes += total_rx_bytes;
1249	u64_stats_update_end(&rx_ring->syncp);
1250	rx_ring->q_vector->rx.total_packets += total_rx_packets;
1251	rx_ring->q_vector->rx.total_bytes += total_rx_bytes;
1252
1253	/* guarantee a trip back through this routine if there was a failure */
1254	return failure ? budget : (int)total_rx_packets;
1255}
1256
1257static inline u32 iavf_buildreg_itr(const int type, u16 itr)
1258{
1259	u32 val;
1260
1261	/* We don't bother with setting the CLEARPBA bit as the data sheet
1262	 * points out doing so is "meaningless since it was already
1263	 * auto-cleared". The auto-clearing happens when the interrupt is
1264	 * asserted.
1265	 *
1266	 * Hardware errata 28 for also indicates that writing to a
1267	 * xxINT_DYN_CTLx CSR with INTENA_MSK (bit 31) set to 0 will clear
1268	 * an event in the PBA anyway so we need to rely on the automask
1269	 * to hold pending events for us until the interrupt is re-enabled
1270	 *
1271	 * The itr value is reported in microseconds, and the register
1272	 * value is recorded in 2 microsecond units. For this reason we
1273	 * only need to shift by the interval shift - 1 instead of the
1274	 * full value.
1275	 */
1276	itr &= IAVF_ITR_MASK;
1277
1278	val = IAVF_VFINT_DYN_CTLN1_INTENA_MASK |
1279	      (type << IAVF_VFINT_DYN_CTLN1_ITR_INDX_SHIFT) |
1280	      (itr << (IAVF_VFINT_DYN_CTLN1_INTERVAL_SHIFT - 1));
1281
1282	return val;
1283}
1284
1285/* a small macro to shorten up some long lines */
1286#define INTREG IAVF_VFINT_DYN_CTLN1
1287
1288/* The act of updating the ITR will cause it to immediately trigger. In order
1289 * to prevent this from throwing off adaptive update statistics we defer the
1290 * update so that it can only happen so often. So after either Tx or Rx are
1291 * updated we make the adaptive scheme wait until either the ITR completely
1292 * expires via the next_update expiration or we have been through at least
1293 * 3 interrupts.
1294 */
1295#define ITR_COUNTDOWN_START 3
1296
1297/**
1298 * iavf_update_enable_itr - Update itr and re-enable MSIX interrupt
1299 * @vsi: the VSI we care about
1300 * @q_vector: q_vector for which itr is being updated and interrupt enabled
1301 *
1302 **/
1303static void iavf_update_enable_itr(struct iavf_vsi *vsi,
1304				   struct iavf_q_vector *q_vector)
1305{
1306	struct iavf_hw *hw = &vsi->back->hw;
1307	u32 intval;
1308
1309	/* These will do nothing if dynamic updates are not enabled */
1310	iavf_update_itr(q_vector, &q_vector->tx);
1311	iavf_update_itr(q_vector, &q_vector->rx);
1312
1313	/* This block of logic allows us to get away with only updating
1314	 * one ITR value with each interrupt. The idea is to perform a
1315	 * pseudo-lazy update with the following criteria.
1316	 *
1317	 * 1. Rx is given higher priority than Tx if both are in same state
1318	 * 2. If we must reduce an ITR that is given highest priority.
1319	 * 3. We then give priority to increasing ITR based on amount.
1320	 */
1321	if (q_vector->rx.target_itr < q_vector->rx.current_itr) {
1322		/* Rx ITR needs to be reduced, this is highest priority */
1323		intval = iavf_buildreg_itr(IAVF_RX_ITR,
1324					   q_vector->rx.target_itr);
1325		q_vector->rx.current_itr = q_vector->rx.target_itr;
1326		q_vector->itr_countdown = ITR_COUNTDOWN_START;
1327	} else if ((q_vector->tx.target_itr < q_vector->tx.current_itr) ||
1328		   ((q_vector->rx.target_itr - q_vector->rx.current_itr) <
1329		    (q_vector->tx.target_itr - q_vector->tx.current_itr))) {
1330		/* Tx ITR needs to be reduced, this is second priority
1331		 * Tx ITR needs to be increased more than Rx, fourth priority
1332		 */
1333		intval = iavf_buildreg_itr(IAVF_TX_ITR,
1334					   q_vector->tx.target_itr);
1335		q_vector->tx.current_itr = q_vector->tx.target_itr;
1336		q_vector->itr_countdown = ITR_COUNTDOWN_START;
1337	} else if (q_vector->rx.current_itr != q_vector->rx.target_itr) {
1338		/* Rx ITR needs to be increased, third priority */
1339		intval = iavf_buildreg_itr(IAVF_RX_ITR,
1340					   q_vector->rx.target_itr);
1341		q_vector->rx.current_itr = q_vector->rx.target_itr;
1342		q_vector->itr_countdown = ITR_COUNTDOWN_START;
1343	} else {
1344		/* No ITR update, lowest priority */
1345		intval = iavf_buildreg_itr(IAVF_ITR_NONE, 0);
1346		if (q_vector->itr_countdown)
1347			q_vector->itr_countdown--;
1348	}
1349
1350	if (!test_bit(__IAVF_VSI_DOWN, vsi->state))
1351		wr32(hw, INTREG(q_vector->reg_idx), intval);
1352}
1353
1354/**
1355 * iavf_napi_poll - NAPI polling Rx/Tx cleanup routine
1356 * @napi: napi struct with our devices info in it
1357 * @budget: amount of work driver is allowed to do this pass, in packets
1358 *
1359 * This function will clean all queues associated with a q_vector.
1360 *
1361 * Returns the amount of work done
1362 **/
1363int iavf_napi_poll(struct napi_struct *napi, int budget)
1364{
1365	struct iavf_q_vector *q_vector =
1366			       container_of(napi, struct iavf_q_vector, napi);
1367	struct iavf_vsi *vsi = q_vector->vsi;
1368	struct iavf_ring *ring;
1369	bool clean_complete = true;
1370	bool arm_wb = false;
1371	int budget_per_ring;
1372	int work_done = 0;
1373
1374	if (test_bit(__IAVF_VSI_DOWN, vsi->state)) {
1375		napi_complete(napi);
1376		return 0;
1377	}
1378
1379	/* Since the actual Tx work is minimal, we can give the Tx a larger
1380	 * budget and be more aggressive about cleaning up the Tx descriptors.
1381	 */
1382	iavf_for_each_ring(ring, q_vector->tx) {
1383		if (!iavf_clean_tx_irq(vsi, ring, budget)) {
1384			clean_complete = false;
1385			continue;
1386		}
1387		arm_wb |= !!(ring->flags & IAVF_TXR_FLAGS_ARM_WB);
1388		ring->flags &= ~IAVF_TXR_FLAGS_ARM_WB;
1389	}
1390
1391	/* Handle case where we are called by netpoll with a budget of 0 */
1392	if (budget <= 0)
1393		goto tx_only;
1394
1395	/* We attempt to distribute budget to each Rx queue fairly, but don't
1396	 * allow the budget to go below 1 because that would exit polling early.
1397	 */
1398	budget_per_ring = max(budget/q_vector->num_ringpairs, 1);
1399
1400	iavf_for_each_ring(ring, q_vector->rx) {
1401		int cleaned = iavf_clean_rx_irq(ring, budget_per_ring);
1402
1403		work_done += cleaned;
1404		/* if we clean as many as budgeted, we must not be done */
1405		if (cleaned >= budget_per_ring)
1406			clean_complete = false;
1407	}
1408
1409	/* If work not completed, return budget and polling will return */
1410	if (!clean_complete) {
1411		int cpu_id = smp_processor_id();
1412
1413		/* It is possible that the interrupt affinity has changed but,
1414		 * if the cpu is pegged at 100%, polling will never exit while
1415		 * traffic continues and the interrupt will be stuck on this
1416		 * cpu.  We check to make sure affinity is correct before we
1417		 * continue to poll, otherwise we must stop polling so the
1418		 * interrupt can move to the correct cpu.
1419		 */
1420		if (!cpumask_test_cpu(cpu_id, &q_vector->affinity_mask)) {
1421			/* Tell napi that we are done polling */
1422			napi_complete_done(napi, work_done);
1423
1424			/* Force an interrupt */
1425			iavf_force_wb(vsi, q_vector);
1426
1427			/* Return budget-1 so that polling stops */
1428			return budget - 1;
1429		}
1430tx_only:
1431		if (arm_wb) {
1432			q_vector->tx.ring[0].tx_stats.tx_force_wb++;
1433			iavf_enable_wb_on_itr(vsi, q_vector);
1434		}
1435		return budget;
1436	}
1437
1438	if (vsi->back->flags & IAVF_TXR_FLAGS_WB_ON_ITR)
1439		q_vector->arm_wb_state = false;
1440
1441	/* Exit the polling mode, but don't re-enable interrupts if stack might
1442	 * poll us due to busy-polling
1443	 */
1444	if (likely(napi_complete_done(napi, work_done)))
1445		iavf_update_enable_itr(vsi, q_vector);
1446
1447	return min_t(int, work_done, budget - 1);
1448}
1449
1450/**
1451 * iavf_tx_prepare_vlan_flags - prepare generic TX VLAN tagging flags for HW
1452 * @skb:     send buffer
1453 * @tx_ring: ring to send buffer on
1454 * @flags:   the tx flags to be set
1455 *
1456 * Checks the skb and set up correspondingly several generic transmit flags
1457 * related to VLAN tagging for the HW, such as VLAN, DCB, etc.
1458 *
1459 * Returns error code indicate the frame should be dropped upon error and the
1460 * otherwise  returns 0 to indicate the flags has been set properly.
1461 **/
1462static void iavf_tx_prepare_vlan_flags(struct sk_buff *skb,
1463				       struct iavf_ring *tx_ring, u32 *flags)
1464{
1465	u32  tx_flags = 0;
1466
1467
1468	/* stack will only request hardware VLAN insertion offload for protocols
1469	 * that the driver supports and has enabled
1470	 */
1471	if (!skb_vlan_tag_present(skb))
1472		return;
1473
1474	tx_flags |= skb_vlan_tag_get(skb) << IAVF_TX_FLAGS_VLAN_SHIFT;
1475	if (tx_ring->flags & IAVF_TXR_FLAGS_VLAN_TAG_LOC_L2TAG2) {
1476		tx_flags |= IAVF_TX_FLAGS_HW_OUTER_SINGLE_VLAN;
1477	} else if (tx_ring->flags & IAVF_TXRX_FLAGS_VLAN_TAG_LOC_L2TAG1) {
1478		tx_flags |= IAVF_TX_FLAGS_HW_VLAN;
1479	} else {
1480		dev_dbg(tx_ring->dev, "Unsupported Tx VLAN tag location requested\n");
1481		return;
1482	}
1483
1484	*flags = tx_flags;
1485}
1486
1487/**
1488 * iavf_tso - set up the tso context descriptor
1489 * @first:    pointer to first Tx buffer for xmit
1490 * @hdr_len:  ptr to the size of the packet header
1491 * @cd_type_cmd_tso_mss: Quad Word 1
1492 *
1493 * Returns 0 if no TSO can happen, 1 if tso is going, or error
1494 **/
1495static int iavf_tso(struct iavf_tx_buffer *first, u8 *hdr_len,
1496		    u64 *cd_type_cmd_tso_mss)
1497{
1498	struct sk_buff *skb = first->skb;
1499	u64 cd_cmd, cd_tso_len, cd_mss;
1500	union {
1501		struct iphdr *v4;
1502		struct ipv6hdr *v6;
1503		unsigned char *hdr;
1504	} ip;
1505	union {
1506		struct tcphdr *tcp;
1507		struct udphdr *udp;
1508		unsigned char *hdr;
1509	} l4;
1510	u32 paylen, l4_offset;
1511	u16 gso_segs, gso_size;
1512	int err;
1513
1514	if (skb->ip_summed != CHECKSUM_PARTIAL)
1515		return 0;
1516
1517	if (!skb_is_gso(skb))
1518		return 0;
1519
1520	err = skb_cow_head(skb, 0);
1521	if (err < 0)
1522		return err;
1523
1524	ip.hdr = skb_network_header(skb);
1525	l4.hdr = skb_transport_header(skb);
1526
1527	/* initialize outer IP header fields */
1528	if (ip.v4->version == 4) {
1529		ip.v4->tot_len = 0;
1530		ip.v4->check = 0;
1531	} else {
1532		ip.v6->payload_len = 0;
1533	}
1534
1535	if (skb_shinfo(skb)->gso_type & (SKB_GSO_GRE |
1536					 SKB_GSO_GRE_CSUM |
1537					 SKB_GSO_IPXIP4 |
1538					 SKB_GSO_IPXIP6 |
1539					 SKB_GSO_UDP_TUNNEL |
1540					 SKB_GSO_UDP_TUNNEL_CSUM)) {
1541		if (!(skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL) &&
1542		    (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM)) {
1543			l4.udp->len = 0;
1544
1545			/* determine offset of outer transport header */
1546			l4_offset = l4.hdr - skb->data;
1547
1548			/* remove payload length from outer checksum */
1549			paylen = skb->len - l4_offset;
1550			csum_replace_by_diff(&l4.udp->check,
1551					     (__force __wsum)htonl(paylen));
1552		}
1553
1554		/* reset pointers to inner headers */
1555		ip.hdr = skb_inner_network_header(skb);
1556		l4.hdr = skb_inner_transport_header(skb);
1557
1558		/* initialize inner IP header fields */
1559		if (ip.v4->version == 4) {
1560			ip.v4->tot_len = 0;
1561			ip.v4->check = 0;
1562		} else {
1563			ip.v6->payload_len = 0;
1564		}
1565	}
1566
1567	/* determine offset of inner transport header */
1568	l4_offset = l4.hdr - skb->data;
1569	/* remove payload length from inner checksum */
1570	paylen = skb->len - l4_offset;
1571
1572	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) {
1573		csum_replace_by_diff(&l4.udp->check,
1574				     (__force __wsum)htonl(paylen));
1575		/* compute length of UDP segmentation header */
1576		*hdr_len = (u8)sizeof(l4.udp) + l4_offset;
1577	} else {
1578		csum_replace_by_diff(&l4.tcp->check,
1579				     (__force __wsum)htonl(paylen));
1580		/* compute length of TCP segmentation header */
1581		*hdr_len = (u8)((l4.tcp->doff * 4) + l4_offset);
1582	}
1583
1584	/* pull values out of skb_shinfo */
1585	gso_size = skb_shinfo(skb)->gso_size;
1586	gso_segs = skb_shinfo(skb)->gso_segs;
1587
1588	/* update GSO size and bytecount with header size */
1589	first->gso_segs = gso_segs;
1590	first->bytecount += (first->gso_segs - 1) * *hdr_len;
1591
1592	/* find the field values */
1593	cd_cmd = IAVF_TX_CTX_DESC_TSO;
1594	cd_tso_len = skb->len - *hdr_len;
1595	cd_mss = gso_size;
1596	*cd_type_cmd_tso_mss |= (cd_cmd << IAVF_TXD_CTX_QW1_CMD_SHIFT) |
1597				(cd_tso_len << IAVF_TXD_CTX_QW1_TSO_LEN_SHIFT) |
1598				(cd_mss << IAVF_TXD_CTX_QW1_MSS_SHIFT);
1599	return 1;
1600}
1601
1602/**
1603 * iavf_tx_enable_csum - Enable Tx checksum offloads
1604 * @skb: send buffer
1605 * @tx_flags: pointer to Tx flags currently set
1606 * @td_cmd: Tx descriptor command bits to set
1607 * @td_offset: Tx descriptor header offsets to set
1608 * @tx_ring: Tx descriptor ring
1609 * @cd_tunneling: ptr to context desc bits
1610 **/
1611static int iavf_tx_enable_csum(struct sk_buff *skb, u32 *tx_flags,
1612			       u32 *td_cmd, u32 *td_offset,
1613			       struct iavf_ring *tx_ring,
1614			       u32 *cd_tunneling)
1615{
1616	union {
1617		struct iphdr *v4;
1618		struct ipv6hdr *v6;
1619		unsigned char *hdr;
1620	} ip;
1621	union {
1622		struct tcphdr *tcp;
1623		struct udphdr *udp;
1624		unsigned char *hdr;
1625	} l4;
1626	unsigned char *exthdr;
1627	u32 offset, cmd = 0;
1628	__be16 frag_off;
1629	u8 l4_proto = 0;
1630
1631	if (skb->ip_summed != CHECKSUM_PARTIAL)
1632		return 0;
1633
1634	ip.hdr = skb_network_header(skb);
1635	l4.hdr = skb_transport_header(skb);
1636
1637	/* compute outer L2 header size */
1638	offset = ((ip.hdr - skb->data) / 2) << IAVF_TX_DESC_LENGTH_MACLEN_SHIFT;
1639
1640	if (skb->encapsulation) {
1641		u32 tunnel = 0;
1642		/* define outer network header type */
1643		if (*tx_flags & IAVF_TX_FLAGS_IPV4) {
1644			tunnel |= (*tx_flags & IAVF_TX_FLAGS_TSO) ?
1645				  IAVF_TX_CTX_EXT_IP_IPV4 :
1646				  IAVF_TX_CTX_EXT_IP_IPV4_NO_CSUM;
1647
1648			l4_proto = ip.v4->protocol;
1649		} else if (*tx_flags & IAVF_TX_FLAGS_IPV6) {
1650			tunnel |= IAVF_TX_CTX_EXT_IP_IPV6;
1651
1652			exthdr = ip.hdr + sizeof(*ip.v6);
1653			l4_proto = ip.v6->nexthdr;
1654			if (l4.hdr != exthdr)
1655				ipv6_skip_exthdr(skb, exthdr - skb->data,
1656						 &l4_proto, &frag_off);
1657		}
1658
1659		/* define outer transport */
1660		switch (l4_proto) {
1661		case IPPROTO_UDP:
1662			tunnel |= IAVF_TXD_CTX_UDP_TUNNELING;
1663			*tx_flags |= IAVF_TX_FLAGS_VXLAN_TUNNEL;
1664			break;
1665		case IPPROTO_GRE:
1666			tunnel |= IAVF_TXD_CTX_GRE_TUNNELING;
1667			*tx_flags |= IAVF_TX_FLAGS_VXLAN_TUNNEL;
1668			break;
1669		case IPPROTO_IPIP:
1670		case IPPROTO_IPV6:
1671			*tx_flags |= IAVF_TX_FLAGS_VXLAN_TUNNEL;
1672			l4.hdr = skb_inner_network_header(skb);
1673			break;
1674		default:
1675			if (*tx_flags & IAVF_TX_FLAGS_TSO)
1676				return -1;
1677
1678			skb_checksum_help(skb);
1679			return 0;
1680		}
1681
1682		/* compute outer L3 header size */
1683		tunnel |= ((l4.hdr - ip.hdr) / 4) <<
1684			  IAVF_TXD_CTX_QW0_EXT_IPLEN_SHIFT;
1685
1686		/* switch IP header pointer from outer to inner header */
1687		ip.hdr = skb_inner_network_header(skb);
1688
1689		/* compute tunnel header size */
1690		tunnel |= ((ip.hdr - l4.hdr) / 2) <<
1691			  IAVF_TXD_CTX_QW0_NATLEN_SHIFT;
1692
1693		/* indicate if we need to offload outer UDP header */
1694		if ((*tx_flags & IAVF_TX_FLAGS_TSO) &&
1695		    !(skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL) &&
1696		    (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM))
1697			tunnel |= IAVF_TXD_CTX_QW0_L4T_CS_MASK;
1698
1699		/* record tunnel offload values */
1700		*cd_tunneling |= tunnel;
1701
1702		/* switch L4 header pointer from outer to inner */
1703		l4.hdr = skb_inner_transport_header(skb);
1704		l4_proto = 0;
1705
1706		/* reset type as we transition from outer to inner headers */
1707		*tx_flags &= ~(IAVF_TX_FLAGS_IPV4 | IAVF_TX_FLAGS_IPV6);
1708		if (ip.v4->version == 4)
1709			*tx_flags |= IAVF_TX_FLAGS_IPV4;
1710		if (ip.v6->version == 6)
1711			*tx_flags |= IAVF_TX_FLAGS_IPV6;
1712	}
1713
1714	/* Enable IP checksum offloads */
1715	if (*tx_flags & IAVF_TX_FLAGS_IPV4) {
1716		l4_proto = ip.v4->protocol;
1717		/* the stack computes the IP header already, the only time we
1718		 * need the hardware to recompute it is in the case of TSO.
1719		 */
1720		cmd |= (*tx_flags & IAVF_TX_FLAGS_TSO) ?
1721		       IAVF_TX_DESC_CMD_IIPT_IPV4_CSUM :
1722		       IAVF_TX_DESC_CMD_IIPT_IPV4;
1723	} else if (*tx_flags & IAVF_TX_FLAGS_IPV6) {
1724		cmd |= IAVF_TX_DESC_CMD_IIPT_IPV6;
1725
1726		exthdr = ip.hdr + sizeof(*ip.v6);
1727		l4_proto = ip.v6->nexthdr;
1728		if (l4.hdr != exthdr)
1729			ipv6_skip_exthdr(skb, exthdr - skb->data,
1730					 &l4_proto, &frag_off);
1731	}
1732
1733	/* compute inner L3 header size */
1734	offset |= ((l4.hdr - ip.hdr) / 4) << IAVF_TX_DESC_LENGTH_IPLEN_SHIFT;
1735
1736	/* Enable L4 checksum offloads */
1737	switch (l4_proto) {
1738	case IPPROTO_TCP:
1739		/* enable checksum offloads */
1740		cmd |= IAVF_TX_DESC_CMD_L4T_EOFT_TCP;
1741		offset |= l4.tcp->doff << IAVF_TX_DESC_LENGTH_L4_FC_LEN_SHIFT;
1742		break;
1743	case IPPROTO_SCTP:
1744		/* enable SCTP checksum offload */
1745		cmd |= IAVF_TX_DESC_CMD_L4T_EOFT_SCTP;
1746		offset |= (sizeof(struct sctphdr) >> 2) <<
1747			  IAVF_TX_DESC_LENGTH_L4_FC_LEN_SHIFT;
1748		break;
1749	case IPPROTO_UDP:
1750		/* enable UDP checksum offload */
1751		cmd |= IAVF_TX_DESC_CMD_L4T_EOFT_UDP;
1752		offset |= (sizeof(struct udphdr) >> 2) <<
1753			  IAVF_TX_DESC_LENGTH_L4_FC_LEN_SHIFT;
1754		break;
1755	default:
1756		if (*tx_flags & IAVF_TX_FLAGS_TSO)
1757			return -1;
1758		skb_checksum_help(skb);
1759		return 0;
1760	}
1761
1762	*td_cmd |= cmd;
1763	*td_offset |= offset;
1764
1765	return 1;
1766}
1767
1768/**
1769 * iavf_create_tx_ctx - Build the Tx context descriptor
1770 * @tx_ring:  ring to create the descriptor on
1771 * @cd_type_cmd_tso_mss: Quad Word 1
1772 * @cd_tunneling: Quad Word 0 - bits 0-31
1773 * @cd_l2tag2: Quad Word 0 - bits 32-63
1774 **/
1775static void iavf_create_tx_ctx(struct iavf_ring *tx_ring,
1776			       const u64 cd_type_cmd_tso_mss,
1777			       const u32 cd_tunneling, const u32 cd_l2tag2)
1778{
1779	struct iavf_tx_context_desc *context_desc;
1780	int i = tx_ring->next_to_use;
1781
1782	if ((cd_type_cmd_tso_mss == IAVF_TX_DESC_DTYPE_CONTEXT) &&
1783	    !cd_tunneling && !cd_l2tag2)
1784		return;
1785
1786	/* grab the next descriptor */
1787	context_desc = IAVF_TX_CTXTDESC(tx_ring, i);
1788
1789	i++;
1790	tx_ring->next_to_use = (i < tx_ring->count) ? i : 0;
1791
1792	/* cpu_to_le32 and assign to struct fields */
1793	context_desc->tunneling_params = cpu_to_le32(cd_tunneling);
1794	context_desc->l2tag2 = cpu_to_le16(cd_l2tag2);
1795	context_desc->rsvd = cpu_to_le16(0);
1796	context_desc->type_cmd_tso_mss = cpu_to_le64(cd_type_cmd_tso_mss);
1797}
1798
1799/**
1800 * __iavf_chk_linearize - Check if there are more than 8 buffers per packet
1801 * @skb:      send buffer
1802 *
1803 * Note: Our HW can't DMA more than 8 buffers to build a packet on the wire
1804 * and so we need to figure out the cases where we need to linearize the skb.
1805 *
1806 * For TSO we need to count the TSO header and segment payload separately.
1807 * As such we need to check cases where we have 7 fragments or more as we
1808 * can potentially require 9 DMA transactions, 1 for the TSO header, 1 for
1809 * the segment payload in the first descriptor, and another 7 for the
1810 * fragments.
1811 **/
1812bool __iavf_chk_linearize(struct sk_buff *skb)
1813{
1814	const skb_frag_t *frag, *stale;
1815	int nr_frags, sum;
1816
1817	/* no need to check if number of frags is less than 7 */
1818	nr_frags = skb_shinfo(skb)->nr_frags;
1819	if (nr_frags < (IAVF_MAX_BUFFER_TXD - 1))
1820		return false;
1821
1822	/* We need to walk through the list and validate that each group
1823	 * of 6 fragments totals at least gso_size.
1824	 */
1825	nr_frags -= IAVF_MAX_BUFFER_TXD - 2;
1826	frag = &skb_shinfo(skb)->frags[0];
1827
1828	/* Initialize size to the negative value of gso_size minus 1.  We
1829	 * use this as the worst case scenerio in which the frag ahead
1830	 * of us only provides one byte which is why we are limited to 6
1831	 * descriptors for a single transmit as the header and previous
1832	 * fragment are already consuming 2 descriptors.
1833	 */
1834	sum = 1 - skb_shinfo(skb)->gso_size;
1835
1836	/* Add size of frags 0 through 4 to create our initial sum */
1837	sum += skb_frag_size(frag++);
1838	sum += skb_frag_size(frag++);
1839	sum += skb_frag_size(frag++);
1840	sum += skb_frag_size(frag++);
1841	sum += skb_frag_size(frag++);
1842
1843	/* Walk through fragments adding latest fragment, testing it, and
1844	 * then removing stale fragments from the sum.
1845	 */
1846	for (stale = &skb_shinfo(skb)->frags[0];; stale++) {
1847		int stale_size = skb_frag_size(stale);
1848
1849		sum += skb_frag_size(frag++);
1850
1851		/* The stale fragment may present us with a smaller
1852		 * descriptor than the actual fragment size. To account
1853		 * for that we need to remove all the data on the front and
1854		 * figure out what the remainder would be in the last
1855		 * descriptor associated with the fragment.
1856		 */
1857		if (stale_size > IAVF_MAX_DATA_PER_TXD) {
1858			int align_pad = -(skb_frag_off(stale)) &
1859					(IAVF_MAX_READ_REQ_SIZE - 1);
1860
1861			sum -= align_pad;
1862			stale_size -= align_pad;
1863
1864			do {
1865				sum -= IAVF_MAX_DATA_PER_TXD_ALIGNED;
1866				stale_size -= IAVF_MAX_DATA_PER_TXD_ALIGNED;
1867			} while (stale_size > IAVF_MAX_DATA_PER_TXD);
1868		}
1869
1870		/* if sum is negative we failed to make sufficient progress */
1871		if (sum < 0)
1872			return true;
1873
1874		if (!nr_frags--)
1875			break;
1876
1877		sum -= stale_size;
1878	}
1879
1880	return false;
1881}
1882
1883/**
1884 * __iavf_maybe_stop_tx - 2nd level check for tx stop conditions
1885 * @tx_ring: the ring to be checked
1886 * @size:    the size buffer we want to assure is available
1887 *
1888 * Returns -EBUSY if a stop is needed, else 0
1889 **/
1890int __iavf_maybe_stop_tx(struct iavf_ring *tx_ring, int size)
1891{
1892	netif_stop_subqueue(tx_ring->netdev, tx_ring->queue_index);
1893	/* Memory barrier before checking head and tail */
1894	smp_mb();
1895
1896	/* Check again in a case another CPU has just made room available. */
1897	if (likely(IAVF_DESC_UNUSED(tx_ring) < size))
1898		return -EBUSY;
1899
1900	/* A reprieve! - use start_queue because it doesn't call schedule */
1901	netif_start_subqueue(tx_ring->netdev, tx_ring->queue_index);
1902	++tx_ring->tx_stats.restart_queue;
1903	return 0;
1904}
1905
1906/**
1907 * iavf_tx_map - Build the Tx descriptor
1908 * @tx_ring:  ring to send buffer on
1909 * @skb:      send buffer
1910 * @first:    first buffer info buffer to use
1911 * @tx_flags: collected send information
1912 * @hdr_len:  size of the packet header
1913 * @td_cmd:   the command field in the descriptor
1914 * @td_offset: offset for checksum or crc
1915 **/
1916static void iavf_tx_map(struct iavf_ring *tx_ring, struct sk_buff *skb,
1917			struct iavf_tx_buffer *first, u32 tx_flags,
1918			const u8 hdr_len, u32 td_cmd, u32 td_offset)
1919{
1920	unsigned int data_len = skb->data_len;
1921	unsigned int size = skb_headlen(skb);
1922	skb_frag_t *frag;
1923	struct iavf_tx_buffer *tx_bi;
1924	struct iavf_tx_desc *tx_desc;
1925	u16 i = tx_ring->next_to_use;
1926	u32 td_tag = 0;
1927	dma_addr_t dma;
1928
1929	if (tx_flags & IAVF_TX_FLAGS_HW_VLAN) {
1930		td_cmd |= IAVF_TX_DESC_CMD_IL2TAG1;
1931		td_tag = FIELD_GET(IAVF_TX_FLAGS_VLAN_MASK, tx_flags);
 
1932	}
1933
1934	first->tx_flags = tx_flags;
1935
1936	dma = dma_map_single(tx_ring->dev, skb->data, size, DMA_TO_DEVICE);
1937
1938	tx_desc = IAVF_TX_DESC(tx_ring, i);
1939	tx_bi = first;
1940
1941	for (frag = &skb_shinfo(skb)->frags[0];; frag++) {
1942		unsigned int max_data = IAVF_MAX_DATA_PER_TXD_ALIGNED;
1943
1944		if (dma_mapping_error(tx_ring->dev, dma))
1945			goto dma_error;
1946
1947		/* record length, and DMA address */
1948		dma_unmap_len_set(tx_bi, len, size);
1949		dma_unmap_addr_set(tx_bi, dma, dma);
1950
1951		/* align size to end of page */
1952		max_data += -dma & (IAVF_MAX_READ_REQ_SIZE - 1);
1953		tx_desc->buffer_addr = cpu_to_le64(dma);
1954
1955		while (unlikely(size > IAVF_MAX_DATA_PER_TXD)) {
1956			tx_desc->cmd_type_offset_bsz =
1957				build_ctob(td_cmd, td_offset,
1958					   max_data, td_tag);
1959
1960			tx_desc++;
1961			i++;
1962
1963			if (i == tx_ring->count) {
1964				tx_desc = IAVF_TX_DESC(tx_ring, 0);
1965				i = 0;
1966			}
1967
1968			dma += max_data;
1969			size -= max_data;
1970
1971			max_data = IAVF_MAX_DATA_PER_TXD_ALIGNED;
1972			tx_desc->buffer_addr = cpu_to_le64(dma);
1973		}
1974
1975		if (likely(!data_len))
1976			break;
1977
1978		tx_desc->cmd_type_offset_bsz = build_ctob(td_cmd, td_offset,
1979							  size, td_tag);
1980
1981		tx_desc++;
1982		i++;
1983
1984		if (i == tx_ring->count) {
1985			tx_desc = IAVF_TX_DESC(tx_ring, 0);
1986			i = 0;
1987		}
1988
1989		size = skb_frag_size(frag);
1990		data_len -= size;
1991
1992		dma = skb_frag_dma_map(tx_ring->dev, frag, 0, size,
1993				       DMA_TO_DEVICE);
1994
1995		tx_bi = &tx_ring->tx_bi[i];
1996	}
1997
1998	netdev_tx_sent_queue(txring_txq(tx_ring), first->bytecount);
1999
2000	i++;
2001	if (i == tx_ring->count)
2002		i = 0;
2003
2004	tx_ring->next_to_use = i;
2005
2006	iavf_maybe_stop_tx(tx_ring, DESC_NEEDED);
2007
2008	/* write last descriptor with RS and EOP bits */
2009	td_cmd |= IAVF_TXD_CMD;
2010	tx_desc->cmd_type_offset_bsz =
2011			build_ctob(td_cmd, td_offset, size, td_tag);
2012
2013	skb_tx_timestamp(skb);
2014
2015	/* Force memory writes to complete before letting h/w know there
2016	 * are new descriptors to fetch.
2017	 *
2018	 * We also use this memory barrier to make certain all of the
2019	 * status bits have been updated before next_to_watch is written.
2020	 */
2021	wmb();
2022
2023	/* set next_to_watch value indicating a packet is present */
2024	first->next_to_watch = tx_desc;
2025
2026	/* notify HW of packet */
2027	if (netif_xmit_stopped(txring_txq(tx_ring)) || !netdev_xmit_more()) {
2028		writel(i, tx_ring->tail);
2029	}
2030
2031	return;
2032
2033dma_error:
2034	dev_info(tx_ring->dev, "TX DMA map failed\n");
2035
2036	/* clear dma mappings for failed tx_bi map */
2037	for (;;) {
2038		tx_bi = &tx_ring->tx_bi[i];
2039		iavf_unmap_and_free_tx_resource(tx_ring, tx_bi);
2040		if (tx_bi == first)
2041			break;
2042		if (i == 0)
2043			i = tx_ring->count;
2044		i--;
2045	}
2046
2047	tx_ring->next_to_use = i;
2048}
2049
2050/**
2051 * iavf_xmit_frame_ring - Sends buffer on Tx ring
2052 * @skb:     send buffer
2053 * @tx_ring: ring to send buffer on
2054 *
2055 * Returns NETDEV_TX_OK if sent, else an error code
2056 **/
2057static netdev_tx_t iavf_xmit_frame_ring(struct sk_buff *skb,
2058					struct iavf_ring *tx_ring)
2059{
2060	u64 cd_type_cmd_tso_mss = IAVF_TX_DESC_DTYPE_CONTEXT;
2061	u32 cd_tunneling = 0, cd_l2tag2 = 0;
2062	struct iavf_tx_buffer *first;
2063	u32 td_offset = 0;
2064	u32 tx_flags = 0;
2065	__be16 protocol;
2066	u32 td_cmd = 0;
2067	u8 hdr_len = 0;
2068	int tso, count;
2069
2070	/* prefetch the data, we'll need it later */
2071	prefetch(skb->data);
2072
2073	iavf_trace(xmit_frame_ring, skb, tx_ring);
2074
2075	count = iavf_xmit_descriptor_count(skb);
2076	if (iavf_chk_linearize(skb, count)) {
2077		if (__skb_linearize(skb)) {
2078			dev_kfree_skb_any(skb);
2079			return NETDEV_TX_OK;
2080		}
2081		count = iavf_txd_use_count(skb->len);
2082		tx_ring->tx_stats.tx_linearize++;
2083	}
2084
2085	/* need: 1 descriptor per page * PAGE_SIZE/IAVF_MAX_DATA_PER_TXD,
2086	 *       + 1 desc for skb_head_len/IAVF_MAX_DATA_PER_TXD,
2087	 *       + 4 desc gap to avoid the cache line where head is,
2088	 *       + 1 desc for context descriptor,
2089	 * otherwise try next time
2090	 */
2091	if (iavf_maybe_stop_tx(tx_ring, count + 4 + 1)) {
2092		tx_ring->tx_stats.tx_busy++;
2093		return NETDEV_TX_BUSY;
2094	}
2095
2096	/* record the location of the first descriptor for this packet */
2097	first = &tx_ring->tx_bi[tx_ring->next_to_use];
2098	first->skb = skb;
2099	first->bytecount = skb->len;
2100	first->gso_segs = 1;
2101
2102	/* prepare the xmit flags */
2103	iavf_tx_prepare_vlan_flags(skb, tx_ring, &tx_flags);
2104	if (tx_flags & IAVF_TX_FLAGS_HW_OUTER_SINGLE_VLAN) {
2105		cd_type_cmd_tso_mss |= IAVF_TX_CTX_DESC_IL2TAG2 <<
2106			IAVF_TXD_CTX_QW1_CMD_SHIFT;
2107		cd_l2tag2 = FIELD_GET(IAVF_TX_FLAGS_VLAN_MASK, tx_flags);
 
2108	}
2109
2110	/* obtain protocol of skb */
2111	protocol = vlan_get_protocol(skb);
2112
2113	/* setup IPv4/IPv6 offloads */
2114	if (protocol == htons(ETH_P_IP))
2115		tx_flags |= IAVF_TX_FLAGS_IPV4;
2116	else if (protocol == htons(ETH_P_IPV6))
2117		tx_flags |= IAVF_TX_FLAGS_IPV6;
2118
2119	tso = iavf_tso(first, &hdr_len, &cd_type_cmd_tso_mss);
2120
2121	if (tso < 0)
2122		goto out_drop;
2123	else if (tso)
2124		tx_flags |= IAVF_TX_FLAGS_TSO;
2125
2126	/* Always offload the checksum, since it's in the data descriptor */
2127	tso = iavf_tx_enable_csum(skb, &tx_flags, &td_cmd, &td_offset,
2128				  tx_ring, &cd_tunneling);
2129	if (tso < 0)
2130		goto out_drop;
2131
2132	/* always enable CRC insertion offload */
2133	td_cmd |= IAVF_TX_DESC_CMD_ICRC;
2134
2135	iavf_create_tx_ctx(tx_ring, cd_type_cmd_tso_mss,
2136			   cd_tunneling, cd_l2tag2);
2137
2138	iavf_tx_map(tx_ring, skb, first, tx_flags, hdr_len,
2139		    td_cmd, td_offset);
2140
2141	return NETDEV_TX_OK;
2142
2143out_drop:
2144	iavf_trace(xmit_frame_ring_drop, first->skb, tx_ring);
2145	dev_kfree_skb_any(first->skb);
2146	first->skb = NULL;
2147	return NETDEV_TX_OK;
2148}
2149
2150/**
2151 * iavf_xmit_frame - Selects the correct VSI and Tx queue to send buffer
2152 * @skb:    send buffer
2153 * @netdev: network interface device structure
2154 *
2155 * Returns NETDEV_TX_OK if sent, else an error code
2156 **/
2157netdev_tx_t iavf_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
2158{
2159	struct iavf_adapter *adapter = netdev_priv(netdev);
2160	struct iavf_ring *tx_ring = &adapter->tx_rings[skb->queue_mapping];
2161
2162	/* hardware can't handle really short frames, hardware padding works
2163	 * beyond this point
2164	 */
2165	if (unlikely(skb->len < IAVF_MIN_TX_LEN)) {
2166		if (skb_pad(skb, IAVF_MIN_TX_LEN - skb->len))
2167			return NETDEV_TX_OK;
2168		skb->len = IAVF_MIN_TX_LEN;
2169		skb_set_tail_pointer(skb, IAVF_MIN_TX_LEN);
2170	}
2171
2172	return iavf_xmit_frame_ring(skb, tx_ring);
2173}