1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright(c) 2013 - 2018 Intel Corporation. */
3 
4 #include <linux/prefetch.h>
5 
6 #include "iavf.h"
7 #include "iavf_trace.h"
8 #include "iavf_prototype.h"
9 
build_ctob(u32 td_cmd,u32 td_offset,unsigned int size,u32 td_tag)10 static inline __le64 build_ctob(u32 td_cmd, u32 td_offset, unsigned int size,
11 				u32 td_tag)
12 {
13 	return cpu_to_le64(IAVF_TX_DESC_DTYPE_DATA |
14 			   ((u64)td_cmd  << IAVF_TXD_QW1_CMD_SHIFT) |
15 			   ((u64)td_offset << IAVF_TXD_QW1_OFFSET_SHIFT) |
16 			   ((u64)size  << IAVF_TXD_QW1_TX_BUF_SZ_SHIFT) |
17 			   ((u64)td_tag  << IAVF_TXD_QW1_L2TAG1_SHIFT));
18 }
19 
20 #define IAVF_TXD_CMD (IAVF_TX_DESC_CMD_EOP | IAVF_TX_DESC_CMD_RS)
21 
22 /**
23  * iavf_unmap_and_free_tx_resource - Release a Tx buffer
24  * @ring:      the ring that owns the buffer
25  * @tx_buffer: the buffer to free
26  **/
iavf_unmap_and_free_tx_resource(struct iavf_ring * ring,struct iavf_tx_buffer * tx_buffer)27 static void iavf_unmap_and_free_tx_resource(struct iavf_ring *ring,
28 					    struct iavf_tx_buffer *tx_buffer)
29 {
30 	if (tx_buffer->skb) {
31 		if (tx_buffer->tx_flags & IAVF_TX_FLAGS_FD_SB)
32 			kfree(tx_buffer->raw_buf);
33 		else
34 			dev_kfree_skb_any(tx_buffer->skb);
35 		if (dma_unmap_len(tx_buffer, len))
36 			dma_unmap_single(ring->dev,
37 					 dma_unmap_addr(tx_buffer, dma),
38 					 dma_unmap_len(tx_buffer, len),
39 					 DMA_TO_DEVICE);
40 	} else if (dma_unmap_len(tx_buffer, len)) {
41 		dma_unmap_page(ring->dev,
42 			       dma_unmap_addr(tx_buffer, dma),
43 			       dma_unmap_len(tx_buffer, len),
44 			       DMA_TO_DEVICE);
45 	}
46 
47 	tx_buffer->next_to_watch = NULL;
48 	tx_buffer->skb = NULL;
49 	dma_unmap_len_set(tx_buffer, len, 0);
50 	/* tx_buffer must be completely set up in the transmit path */
51 }
52 
53 /**
54  * iavf_clean_tx_ring - Free any empty Tx buffers
55  * @tx_ring: ring to be cleaned
56  **/
iavf_clean_tx_ring(struct iavf_ring * tx_ring)57 void iavf_clean_tx_ring(struct iavf_ring *tx_ring)
58 {
59 	unsigned long bi_size;
60 	u16 i;
61 
62 	/* ring already cleared, nothing to do */
63 	if (!tx_ring->tx_bi)
64 		return;
65 
66 	/* Free all the Tx ring sk_buffs */
67 	for (i = 0; i < tx_ring->count; i++)
68 		iavf_unmap_and_free_tx_resource(tx_ring, &tx_ring->tx_bi[i]);
69 
70 	bi_size = sizeof(struct iavf_tx_buffer) * tx_ring->count;
71 	memset(tx_ring->tx_bi, 0, bi_size);
72 
73 	/* Zero out the descriptor ring */
74 	memset(tx_ring->desc, 0, tx_ring->size);
75 
76 	tx_ring->next_to_use = 0;
77 	tx_ring->next_to_clean = 0;
78 
79 	if (!tx_ring->netdev)
80 		return;
81 
82 	/* cleanup Tx queue statistics */
83 	netdev_tx_reset_queue(txring_txq(tx_ring));
84 }
85 
86 /**
87  * iavf_free_tx_resources - Free Tx resources per queue
88  * @tx_ring: Tx descriptor ring for a specific queue
89  *
90  * Free all transmit software resources
91  **/
iavf_free_tx_resources(struct iavf_ring * tx_ring)92 void iavf_free_tx_resources(struct iavf_ring *tx_ring)
93 {
94 	iavf_clean_tx_ring(tx_ring);
95 	kfree(tx_ring->tx_bi);
96 	tx_ring->tx_bi = NULL;
97 
98 	if (tx_ring->desc) {
99 		dma_free_coherent(tx_ring->dev, tx_ring->size,
100 				  tx_ring->desc, tx_ring->dma);
101 		tx_ring->desc = NULL;
102 	}
103 }
104 
105 /**
106  * iavf_get_tx_pending - how many Tx descriptors not processed
107  * @ring: the ring of descriptors
108  * @in_sw: is tx_pending being checked in SW or HW
109  *
110  * Since there is no access to the ring head register
111  * in XL710, we need to use our local copies
112  **/
iavf_get_tx_pending(struct iavf_ring * ring,bool in_sw)113 u32 iavf_get_tx_pending(struct iavf_ring *ring, bool in_sw)
114 {
115 	u32 head, tail;
116 
117 	/* underlying hardware might not allow access and/or always return
118 	 * 0 for the head/tail registers so just use the cached values
119 	 */
120 	head = ring->next_to_clean;
121 	tail = ring->next_to_use;
122 
123 	if (head != tail)
124 		return (head < tail) ?
125 			tail - head : (tail + ring->count - head);
126 
127 	return 0;
128 }
129 
130 /**
131  * iavf_detect_recover_hung - Function to detect and recover hung_queues
132  * @vsi:  pointer to vsi struct with tx queues
133  *
134  * VSI has netdev and netdev has TX queues. This function is to check each of
135  * those TX queues if they are hung, trigger recovery by issuing SW interrupt.
136  **/
iavf_detect_recover_hung(struct iavf_vsi * vsi)137 void iavf_detect_recover_hung(struct iavf_vsi *vsi)
138 {
139 	struct iavf_ring *tx_ring = NULL;
140 	struct net_device *netdev;
141 	unsigned int i;
142 	int packets;
143 
144 	if (!vsi)
145 		return;
146 
147 	if (test_bit(__IAVF_VSI_DOWN, vsi->state))
148 		return;
149 
150 	netdev = vsi->netdev;
151 	if (!netdev)
152 		return;
153 
154 	if (!netif_carrier_ok(netdev))
155 		return;
156 
157 	for (i = 0; i < vsi->back->num_active_queues; i++) {
158 		tx_ring = &vsi->back->tx_rings[i];
159 		if (tx_ring && tx_ring->desc) {
160 			/* If packet counter has not changed the queue is
161 			 * likely stalled, so force an interrupt for this
162 			 * queue.
163 			 *
164 			 * prev_pkt_ctr would be negative if there was no
165 			 * pending work.
166 			 */
167 			packets = tx_ring->stats.packets & INT_MAX;
168 			if (tx_ring->tx_stats.prev_pkt_ctr == packets) {
169 				iavf_force_wb(vsi, tx_ring->q_vector);
170 				continue;
171 			}
172 
173 			/* Memory barrier between read of packet count and call
174 			 * to iavf_get_tx_pending()
175 			 */
176 			smp_rmb();
177 			tx_ring->tx_stats.prev_pkt_ctr =
178 			  iavf_get_tx_pending(tx_ring, true) ? packets : -1;
179 		}
180 	}
181 }
182 
183 #define WB_STRIDE 4
184 
185 /**
186  * iavf_clean_tx_irq - Reclaim resources after transmit completes
187  * @vsi: the VSI we care about
188  * @tx_ring: Tx ring to clean
189  * @napi_budget: Used to determine if we are in netpoll
190  *
191  * Returns true if there's any budget left (e.g. the clean is finished)
192  **/
iavf_clean_tx_irq(struct iavf_vsi * vsi,struct iavf_ring * tx_ring,int napi_budget)193 static bool iavf_clean_tx_irq(struct iavf_vsi *vsi,
194 			      struct iavf_ring *tx_ring, int napi_budget)
195 {
196 	int i = tx_ring->next_to_clean;
197 	struct iavf_tx_buffer *tx_buf;
198 	struct iavf_tx_desc *tx_desc;
199 	unsigned int total_bytes = 0, total_packets = 0;
200 	unsigned int budget = IAVF_DEFAULT_IRQ_WORK;
201 
202 	tx_buf = &tx_ring->tx_bi[i];
203 	tx_desc = IAVF_TX_DESC(tx_ring, i);
204 	i -= tx_ring->count;
205 
206 	do {
207 		struct iavf_tx_desc *eop_desc = tx_buf->next_to_watch;
208 
209 		/* if next_to_watch is not set then there is no work pending */
210 		if (!eop_desc)
211 			break;
212 
213 		/* prevent any other reads prior to eop_desc */
214 		smp_rmb();
215 
216 		iavf_trace(clean_tx_irq, tx_ring, tx_desc, tx_buf);
217 		/* if the descriptor isn't done, no work yet to do */
218 		if (!(eop_desc->cmd_type_offset_bsz &
219 		      cpu_to_le64(IAVF_TX_DESC_DTYPE_DESC_DONE)))
220 			break;
221 
222 		/* clear next_to_watch to prevent false hangs */
223 		tx_buf->next_to_watch = NULL;
224 
225 		/* update the statistics for this packet */
226 		total_bytes += tx_buf->bytecount;
227 		total_packets += tx_buf->gso_segs;
228 
229 		/* free the skb */
230 		napi_consume_skb(tx_buf->skb, napi_budget);
231 
232 		/* unmap skb header data */
233 		dma_unmap_single(tx_ring->dev,
234 				 dma_unmap_addr(tx_buf, dma),
235 				 dma_unmap_len(tx_buf, len),
236 				 DMA_TO_DEVICE);
237 
238 		/* clear tx_buffer data */
239 		tx_buf->skb = NULL;
240 		dma_unmap_len_set(tx_buf, len, 0);
241 
242 		/* unmap remaining buffers */
243 		while (tx_desc != eop_desc) {
244 			iavf_trace(clean_tx_irq_unmap,
245 				   tx_ring, tx_desc, tx_buf);
246 
247 			tx_buf++;
248 			tx_desc++;
249 			i++;
250 			if (unlikely(!i)) {
251 				i -= tx_ring->count;
252 				tx_buf = tx_ring->tx_bi;
253 				tx_desc = IAVF_TX_DESC(tx_ring, 0);
254 			}
255 
256 			/* unmap any remaining paged data */
257 			if (dma_unmap_len(tx_buf, len)) {
258 				dma_unmap_page(tx_ring->dev,
259 					       dma_unmap_addr(tx_buf, dma),
260 					       dma_unmap_len(tx_buf, len),
261 					       DMA_TO_DEVICE);
262 				dma_unmap_len_set(tx_buf, len, 0);
263 			}
264 		}
265 
266 		/* move us one more past the eop_desc for start of next pkt */
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 		prefetch(tx_desc);
277 
278 		/* update budget accounting */
279 		budget--;
280 	} while (likely(budget));
281 
282 	i += tx_ring->count;
283 	tx_ring->next_to_clean = i;
284 	u64_stats_update_begin(&tx_ring->syncp);
285 	tx_ring->stats.bytes += total_bytes;
286 	tx_ring->stats.packets += total_packets;
287 	u64_stats_update_end(&tx_ring->syncp);
288 	tx_ring->q_vector->tx.total_bytes += total_bytes;
289 	tx_ring->q_vector->tx.total_packets += total_packets;
290 
291 	if (tx_ring->flags & IAVF_TXR_FLAGS_WB_ON_ITR) {
292 		/* check to see if there are < 4 descriptors
293 		 * waiting to be written back, then kick the hardware to force
294 		 * them to be written back in case we stay in NAPI.
295 		 * In this mode on X722 we do not enable Interrupt.
296 		 */
297 		unsigned int j = iavf_get_tx_pending(tx_ring, false);
298 
299 		if (budget &&
300 		    ((j / WB_STRIDE) == 0) && (j > 0) &&
301 		    !test_bit(__IAVF_VSI_DOWN, vsi->state) &&
302 		    (IAVF_DESC_UNUSED(tx_ring) != tx_ring->count))
303 			tx_ring->arm_wb = true;
304 	}
305 
306 	/* notify netdev of completed buffers */
307 	netdev_tx_completed_queue(txring_txq(tx_ring),
308 				  total_packets, total_bytes);
309 
310 #define TX_WAKE_THRESHOLD ((s16)(DESC_NEEDED * 2))
311 	if (unlikely(total_packets && netif_carrier_ok(tx_ring->netdev) &&
312 		     (IAVF_DESC_UNUSED(tx_ring) >= TX_WAKE_THRESHOLD))) {
313 		/* Make sure that anybody stopping the queue after this
314 		 * sees the new next_to_clean.
315 		 */
316 		smp_mb();
317 		if (__netif_subqueue_stopped(tx_ring->netdev,
318 					     tx_ring->queue_index) &&
319 		   !test_bit(__IAVF_VSI_DOWN, vsi->state)) {
320 			netif_wake_subqueue(tx_ring->netdev,
321 					    tx_ring->queue_index);
322 			++tx_ring->tx_stats.restart_queue;
323 		}
324 	}
325 
326 	return !!budget;
327 }
328 
329 /**
330  * iavf_enable_wb_on_itr - Arm hardware to do a wb, interrupts are not enabled
331  * @vsi: the VSI we care about
332  * @q_vector: the vector on which to enable writeback
333  *
334  **/
iavf_enable_wb_on_itr(struct iavf_vsi * vsi,struct iavf_q_vector * q_vector)335 static void iavf_enable_wb_on_itr(struct iavf_vsi *vsi,
336 				  struct iavf_q_vector *q_vector)
337 {
338 	u16 flags = q_vector->tx.ring[0].flags;
339 	u32 val;
340 
341 	if (!(flags & IAVF_TXR_FLAGS_WB_ON_ITR))
342 		return;
343 
344 	if (q_vector->arm_wb_state)
345 		return;
346 
347 	val = IAVF_VFINT_DYN_CTLN1_WB_ON_ITR_MASK |
348 	      IAVF_VFINT_DYN_CTLN1_ITR_INDX_MASK; /* set noitr */
349 
350 	wr32(&vsi->back->hw,
351 	     IAVF_VFINT_DYN_CTLN1(q_vector->reg_idx), val);
352 	q_vector->arm_wb_state = true;
353 }
354 
355 /**
356  * iavf_force_wb - Issue SW Interrupt so HW does a wb
357  * @vsi: the VSI we care about
358  * @q_vector: the vector  on which to force writeback
359  *
360  **/
iavf_force_wb(struct iavf_vsi * vsi,struct iavf_q_vector * q_vector)361 void iavf_force_wb(struct iavf_vsi *vsi, struct iavf_q_vector *q_vector)
362 {
363 	u32 val = IAVF_VFINT_DYN_CTLN1_INTENA_MASK |
364 		  IAVF_VFINT_DYN_CTLN1_ITR_INDX_MASK | /* set noitr */
365 		  IAVF_VFINT_DYN_CTLN1_SWINT_TRIG_MASK |
366 		  IAVF_VFINT_DYN_CTLN1_SW_ITR_INDX_ENA_MASK
367 		  /* allow 00 to be written to the index */;
368 
369 	wr32(&vsi->back->hw,
370 	     IAVF_VFINT_DYN_CTLN1(q_vector->reg_idx),
371 	     val);
372 }
373 
iavf_container_is_rx(struct iavf_q_vector * q_vector,struct iavf_ring_container * rc)374 static inline bool iavf_container_is_rx(struct iavf_q_vector *q_vector,
375 					struct iavf_ring_container *rc)
376 {
377 	return &q_vector->rx == rc;
378 }
379 
380 #define IAVF_AIM_MULTIPLIER_100G	2560
381 #define IAVF_AIM_MULTIPLIER_50G		1280
382 #define IAVF_AIM_MULTIPLIER_40G		1024
383 #define IAVF_AIM_MULTIPLIER_20G		512
384 #define IAVF_AIM_MULTIPLIER_10G		256
385 #define IAVF_AIM_MULTIPLIER_1G		32
386 
iavf_mbps_itr_multiplier(u32 speed_mbps)387 static unsigned int iavf_mbps_itr_multiplier(u32 speed_mbps)
388 {
389 	switch (speed_mbps) {
390 	case SPEED_100000:
391 		return IAVF_AIM_MULTIPLIER_100G;
392 	case SPEED_50000:
393 		return IAVF_AIM_MULTIPLIER_50G;
394 	case SPEED_40000:
395 		return IAVF_AIM_MULTIPLIER_40G;
396 	case SPEED_25000:
397 	case SPEED_20000:
398 		return IAVF_AIM_MULTIPLIER_20G;
399 	case SPEED_10000:
400 	default:
401 		return IAVF_AIM_MULTIPLIER_10G;
402 	case SPEED_1000:
403 	case SPEED_100:
404 		return IAVF_AIM_MULTIPLIER_1G;
405 	}
406 }
407 
408 static unsigned int
iavf_virtchnl_itr_multiplier(enum virtchnl_link_speed speed_virtchnl)409 iavf_virtchnl_itr_multiplier(enum virtchnl_link_speed speed_virtchnl)
410 {
411 	switch (speed_virtchnl) {
412 	case VIRTCHNL_LINK_SPEED_40GB:
413 		return IAVF_AIM_MULTIPLIER_40G;
414 	case VIRTCHNL_LINK_SPEED_25GB:
415 	case VIRTCHNL_LINK_SPEED_20GB:
416 		return IAVF_AIM_MULTIPLIER_20G;
417 	case VIRTCHNL_LINK_SPEED_10GB:
418 	default:
419 		return IAVF_AIM_MULTIPLIER_10G;
420 	case VIRTCHNL_LINK_SPEED_1GB:
421 	case VIRTCHNL_LINK_SPEED_100MB:
422 		return IAVF_AIM_MULTIPLIER_1G;
423 	}
424 }
425 
iavf_itr_divisor(struct iavf_adapter * adapter)426 static unsigned int iavf_itr_divisor(struct iavf_adapter *adapter)
427 {
428 	if (ADV_LINK_SUPPORT(adapter))
429 		return IAVF_ITR_ADAPTIVE_MIN_INC *
430 			iavf_mbps_itr_multiplier(adapter->link_speed_mbps);
431 	else
432 		return IAVF_ITR_ADAPTIVE_MIN_INC *
433 			iavf_virtchnl_itr_multiplier(adapter->link_speed);
434 }
435 
436 /**
437  * iavf_update_itr - update the dynamic ITR value based on statistics
438  * @q_vector: structure containing interrupt and ring information
439  * @rc: structure containing ring performance data
440  *
441  * Stores a new ITR value based on packets and byte
442  * counts during the last interrupt.  The advantage of per interrupt
443  * computation is faster updates and more accurate ITR for the current
444  * traffic pattern.  Constants in this function were computed
445  * based on theoretical maximum wire speed and thresholds were set based
446  * on testing data as well as attempting to minimize response time
447  * while increasing bulk throughput.
448  **/
iavf_update_itr(struct iavf_q_vector * q_vector,struct iavf_ring_container * rc)449 static void iavf_update_itr(struct iavf_q_vector *q_vector,
450 			    struct iavf_ring_container *rc)
451 {
452 	unsigned int avg_wire_size, packets, bytes, itr;
453 	unsigned long next_update = jiffies;
454 
455 	/* If we don't have any rings just leave ourselves set for maximum
456 	 * possible latency so we take ourselves out of the equation.
457 	 */
458 	if (!rc->ring || !ITR_IS_DYNAMIC(rc->ring->itr_setting))
459 		return;
460 
461 	/* For Rx we want to push the delay up and default to low latency.
462 	 * for Tx we want to pull the delay down and default to high latency.
463 	 */
464 	itr = iavf_container_is_rx(q_vector, rc) ?
465 	      IAVF_ITR_ADAPTIVE_MIN_USECS | IAVF_ITR_ADAPTIVE_LATENCY :
466 	      IAVF_ITR_ADAPTIVE_MAX_USECS | IAVF_ITR_ADAPTIVE_LATENCY;
467 
468 	/* If we didn't update within up to 1 - 2 jiffies we can assume
469 	 * that either packets are coming in so slow there hasn't been
470 	 * any work, or that there is so much work that NAPI is dealing
471 	 * with interrupt moderation and we don't need to do anything.
472 	 */
473 	if (time_after(next_update, rc->next_update))
474 		goto clear_counts;
475 
476 	/* If itr_countdown is set it means we programmed an ITR within
477 	 * the last 4 interrupt cycles. This has a side effect of us
478 	 * potentially firing an early interrupt. In order to work around
479 	 * this we need to throw out any data received for a few
480 	 * interrupts following the update.
481 	 */
482 	if (q_vector->itr_countdown) {
483 		itr = rc->target_itr;
484 		goto clear_counts;
485 	}
486 
487 	packets = rc->total_packets;
488 	bytes = rc->total_bytes;
489 
490 	if (iavf_container_is_rx(q_vector, rc)) {
491 		/* If Rx there are 1 to 4 packets and bytes are less than
492 		 * 9000 assume insufficient data to use bulk rate limiting
493 		 * approach unless Tx is already in bulk rate limiting. We
494 		 * are likely latency driven.
495 		 */
496 		if (packets && packets < 4 && bytes < 9000 &&
497 		    (q_vector->tx.target_itr & IAVF_ITR_ADAPTIVE_LATENCY)) {
498 			itr = IAVF_ITR_ADAPTIVE_LATENCY;
499 			goto adjust_by_size;
500 		}
501 	} else if (packets < 4) {
502 		/* If we have Tx and Rx ITR maxed and Tx ITR is running in
503 		 * bulk mode and we are receiving 4 or fewer packets just
504 		 * reset the ITR_ADAPTIVE_LATENCY bit for latency mode so
505 		 * that the Rx can relax.
506 		 */
507 		if (rc->target_itr == IAVF_ITR_ADAPTIVE_MAX_USECS &&
508 		    (q_vector->rx.target_itr & IAVF_ITR_MASK) ==
509 		     IAVF_ITR_ADAPTIVE_MAX_USECS)
510 			goto clear_counts;
511 	} else if (packets > 32) {
512 		/* If we have processed over 32 packets in a single interrupt
513 		 * for Tx assume we need to switch over to "bulk" mode.
514 		 */
515 		rc->target_itr &= ~IAVF_ITR_ADAPTIVE_LATENCY;
516 	}
517 
518 	/* We have no packets to actually measure against. This means
519 	 * either one of the other queues on this vector is active or
520 	 * we are a Tx queue doing TSO with too high of an interrupt rate.
521 	 *
522 	 * Between 4 and 56 we can assume that our current interrupt delay
523 	 * is only slightly too low. As such we should increase it by a small
524 	 * fixed amount.
525 	 */
526 	if (packets < 56) {
527 		itr = rc->target_itr + IAVF_ITR_ADAPTIVE_MIN_INC;
528 		if ((itr & IAVF_ITR_MASK) > IAVF_ITR_ADAPTIVE_MAX_USECS) {
529 			itr &= IAVF_ITR_ADAPTIVE_LATENCY;
530 			itr += IAVF_ITR_ADAPTIVE_MAX_USECS;
531 		}
532 		goto clear_counts;
533 	}
534 
535 	if (packets <= 256) {
536 		itr = min(q_vector->tx.current_itr, q_vector->rx.current_itr);
537 		itr &= IAVF_ITR_MASK;
538 
539 		/* Between 56 and 112 is our "goldilocks" zone where we are
540 		 * working out "just right". Just report that our current
541 		 * ITR is good for us.
542 		 */
543 		if (packets <= 112)
544 			goto clear_counts;
545 
546 		/* If packet count is 128 or greater we are likely looking
547 		 * at a slight overrun of the delay we want. Try halving
548 		 * our delay to see if that will cut the number of packets
549 		 * in half per interrupt.
550 		 */
551 		itr /= 2;
552 		itr &= IAVF_ITR_MASK;
553 		if (itr < IAVF_ITR_ADAPTIVE_MIN_USECS)
554 			itr = IAVF_ITR_ADAPTIVE_MIN_USECS;
555 
556 		goto clear_counts;
557 	}
558 
559 	/* The paths below assume we are dealing with a bulk ITR since
560 	 * number of packets is greater than 256. We are just going to have
561 	 * to compute a value and try to bring the count under control,
562 	 * though for smaller packet sizes there isn't much we can do as
563 	 * NAPI polling will likely be kicking in sooner rather than later.
564 	 */
565 	itr = IAVF_ITR_ADAPTIVE_BULK;
566 
567 adjust_by_size:
568 	/* If packet counts are 256 or greater we can assume we have a gross
569 	 * overestimation of what the rate should be. Instead of trying to fine
570 	 * tune it just use the formula below to try and dial in an exact value
571 	 * give the current packet size of the frame.
572 	 */
573 	avg_wire_size = bytes / packets;
574 
575 	/* The following is a crude approximation of:
576 	 *  wmem_default / (size + overhead) = desired_pkts_per_int
577 	 *  rate / bits_per_byte / (size + ethernet overhead) = pkt_rate
578 	 *  (desired_pkt_rate / pkt_rate) * usecs_per_sec = ITR value
579 	 *
580 	 * Assuming wmem_default is 212992 and overhead is 640 bytes per
581 	 * packet, (256 skb, 64 headroom, 320 shared info), we can reduce the
582 	 * formula down to
583 	 *
584 	 *  (170 * (size + 24)) / (size + 640) = ITR
585 	 *
586 	 * We first do some math on the packet size and then finally bitshift
587 	 * by 8 after rounding up. We also have to account for PCIe link speed
588 	 * difference as ITR scales based on this.
589 	 */
590 	if (avg_wire_size <= 60) {
591 		/* Start at 250k ints/sec */
592 		avg_wire_size = 4096;
593 	} else if (avg_wire_size <= 380) {
594 		/* 250K ints/sec to 60K ints/sec */
595 		avg_wire_size *= 40;
596 		avg_wire_size += 1696;
597 	} else if (avg_wire_size <= 1084) {
598 		/* 60K ints/sec to 36K ints/sec */
599 		avg_wire_size *= 15;
600 		avg_wire_size += 11452;
601 	} else if (avg_wire_size <= 1980) {
602 		/* 36K ints/sec to 30K ints/sec */
603 		avg_wire_size *= 5;
604 		avg_wire_size += 22420;
605 	} else {
606 		/* plateau at a limit of 30K ints/sec */
607 		avg_wire_size = 32256;
608 	}
609 
610 	/* If we are in low latency mode halve our delay which doubles the
611 	 * rate to somewhere between 100K to 16K ints/sec
612 	 */
613 	if (itr & IAVF_ITR_ADAPTIVE_LATENCY)
614 		avg_wire_size /= 2;
615 
616 	/* Resultant value is 256 times larger than it needs to be. This
617 	 * gives us room to adjust the value as needed to either increase
618 	 * or decrease the value based on link speeds of 10G, 2.5G, 1G, etc.
619 	 *
620 	 * Use addition as we have already recorded the new latency flag
621 	 * for the ITR value.
622 	 */
623 	itr += DIV_ROUND_UP(avg_wire_size,
624 			    iavf_itr_divisor(q_vector->adapter)) *
625 		IAVF_ITR_ADAPTIVE_MIN_INC;
626 
627 	if ((itr & IAVF_ITR_MASK) > IAVF_ITR_ADAPTIVE_MAX_USECS) {
628 		itr &= IAVF_ITR_ADAPTIVE_LATENCY;
629 		itr += IAVF_ITR_ADAPTIVE_MAX_USECS;
630 	}
631 
632 clear_counts:
633 	/* write back value */
634 	rc->target_itr = itr;
635 
636 	/* next update should occur within next jiffy */
637 	rc->next_update = next_update + 1;
638 
639 	rc->total_bytes = 0;
640 	rc->total_packets = 0;
641 }
642 
643 /**
644  * iavf_setup_tx_descriptors - Allocate the Tx descriptors
645  * @tx_ring: the tx ring to set up
646  *
647  * Return 0 on success, negative on error
648  **/
iavf_setup_tx_descriptors(struct iavf_ring * tx_ring)649 int iavf_setup_tx_descriptors(struct iavf_ring *tx_ring)
650 {
651 	struct device *dev = tx_ring->dev;
652 	int bi_size;
653 
654 	if (!dev)
655 		return -ENOMEM;
656 
657 	/* warn if we are about to overwrite the pointer */
658 	WARN_ON(tx_ring->tx_bi);
659 	bi_size = sizeof(struct iavf_tx_buffer) * tx_ring->count;
660 	tx_ring->tx_bi = kzalloc(bi_size, GFP_KERNEL);
661 	if (!tx_ring->tx_bi)
662 		goto err;
663 
664 	/* round up to nearest 4K */
665 	tx_ring->size = tx_ring->count * sizeof(struct iavf_tx_desc);
666 	tx_ring->size = ALIGN(tx_ring->size, 4096);
667 	tx_ring->desc = dma_alloc_coherent(dev, tx_ring->size,
668 					   &tx_ring->dma, GFP_KERNEL);
669 	if (!tx_ring->desc) {
670 		dev_info(dev, "Unable to allocate memory for the Tx descriptor ring, size=%d\n",
671 			 tx_ring->size);
672 		goto err;
673 	}
674 
675 	tx_ring->next_to_use = 0;
676 	tx_ring->next_to_clean = 0;
677 	tx_ring->tx_stats.prev_pkt_ctr = -1;
678 	return 0;
679 
680 err:
681 	kfree(tx_ring->tx_bi);
682 	tx_ring->tx_bi = NULL;
683 	return -ENOMEM;
684 }
685 
686 /**
687  * iavf_clean_rx_ring - Free Rx buffers
688  * @rx_ring: ring to be cleaned
689  **/
iavf_clean_rx_ring(struct iavf_ring * rx_ring)690 void iavf_clean_rx_ring(struct iavf_ring *rx_ring)
691 {
692 	unsigned long bi_size;
693 	u16 i;
694 
695 	/* ring already cleared, nothing to do */
696 	if (!rx_ring->rx_bi)
697 		return;
698 
699 	if (rx_ring->skb) {
700 		dev_kfree_skb(rx_ring->skb);
701 		rx_ring->skb = NULL;
702 	}
703 
704 	/* Free all the Rx ring sk_buffs */
705 	for (i = 0; i < rx_ring->count; i++) {
706 		struct iavf_rx_buffer *rx_bi = &rx_ring->rx_bi[i];
707 
708 		if (!rx_bi->page)
709 			continue;
710 
711 		/* Invalidate cache lines that may have been written to by
712 		 * device so that we avoid corrupting memory.
713 		 */
714 		dma_sync_single_range_for_cpu(rx_ring->dev,
715 					      rx_bi->dma,
716 					      rx_bi->page_offset,
717 					      rx_ring->rx_buf_len,
718 					      DMA_FROM_DEVICE);
719 
720 		/* free resources associated with mapping */
721 		dma_unmap_page_attrs(rx_ring->dev, rx_bi->dma,
722 				     iavf_rx_pg_size(rx_ring),
723 				     DMA_FROM_DEVICE,
724 				     IAVF_RX_DMA_ATTR);
725 
726 		__page_frag_cache_drain(rx_bi->page, rx_bi->pagecnt_bias);
727 
728 		rx_bi->page = NULL;
729 		rx_bi->page_offset = 0;
730 	}
731 
732 	bi_size = sizeof(struct iavf_rx_buffer) * rx_ring->count;
733 	memset(rx_ring->rx_bi, 0, bi_size);
734 
735 	/* Zero out the descriptor ring */
736 	memset(rx_ring->desc, 0, rx_ring->size);
737 
738 	rx_ring->next_to_alloc = 0;
739 	rx_ring->next_to_clean = 0;
740 	rx_ring->next_to_use = 0;
741 }
742 
743 /**
744  * iavf_free_rx_resources - Free Rx resources
745  * @rx_ring: ring to clean the resources from
746  *
747  * Free all receive software resources
748  **/
iavf_free_rx_resources(struct iavf_ring * rx_ring)749 void iavf_free_rx_resources(struct iavf_ring *rx_ring)
750 {
751 	iavf_clean_rx_ring(rx_ring);
752 	kfree(rx_ring->rx_bi);
753 	rx_ring->rx_bi = NULL;
754 
755 	if (rx_ring->desc) {
756 		dma_free_coherent(rx_ring->dev, rx_ring->size,
757 				  rx_ring->desc, rx_ring->dma);
758 		rx_ring->desc = NULL;
759 	}
760 }
761 
762 /**
763  * iavf_setup_rx_descriptors - Allocate Rx descriptors
764  * @rx_ring: Rx descriptor ring (for a specific queue) to setup
765  *
766  * Returns 0 on success, negative on failure
767  **/
iavf_setup_rx_descriptors(struct iavf_ring * rx_ring)768 int iavf_setup_rx_descriptors(struct iavf_ring *rx_ring)
769 {
770 	struct device *dev = rx_ring->dev;
771 	int bi_size;
772 
773 	/* warn if we are about to overwrite the pointer */
774 	WARN_ON(rx_ring->rx_bi);
775 	bi_size = sizeof(struct iavf_rx_buffer) * rx_ring->count;
776 	rx_ring->rx_bi = kzalloc(bi_size, GFP_KERNEL);
777 	if (!rx_ring->rx_bi)
778 		goto err;
779 
780 	u64_stats_init(&rx_ring->syncp);
781 
782 	/* Round up to nearest 4K */
783 	rx_ring->size = rx_ring->count * sizeof(union iavf_32byte_rx_desc);
784 	rx_ring->size = ALIGN(rx_ring->size, 4096);
785 	rx_ring->desc = dma_alloc_coherent(dev, rx_ring->size,
786 					   &rx_ring->dma, GFP_KERNEL);
787 
788 	if (!rx_ring->desc) {
789 		dev_info(dev, "Unable to allocate memory for the Rx descriptor ring, size=%d\n",
790 			 rx_ring->size);
791 		goto err;
792 	}
793 
794 	rx_ring->next_to_alloc = 0;
795 	rx_ring->next_to_clean = 0;
796 	rx_ring->next_to_use = 0;
797 
798 	return 0;
799 err:
800 	kfree(rx_ring->rx_bi);
801 	rx_ring->rx_bi = NULL;
802 	return -ENOMEM;
803 }
804 
805 /**
806  * iavf_release_rx_desc - Store the new tail and head values
807  * @rx_ring: ring to bump
808  * @val: new head index
809  **/
iavf_release_rx_desc(struct iavf_ring * rx_ring,u32 val)810 static inline void iavf_release_rx_desc(struct iavf_ring *rx_ring, u32 val)
811 {
812 	rx_ring->next_to_use = val;
813 
814 	/* update next to alloc since we have filled the ring */
815 	rx_ring->next_to_alloc = val;
816 
817 	/* Force memory writes to complete before letting h/w
818 	 * know there are new descriptors to fetch.  (Only
819 	 * applicable for weak-ordered memory model archs,
820 	 * such as IA-64).
821 	 */
822 	wmb();
823 	writel(val, rx_ring->tail);
824 }
825 
826 /**
827  * iavf_rx_offset - Return expected offset into page to access data
828  * @rx_ring: Ring we are requesting offset of
829  *
830  * Returns the offset value for ring into the data buffer.
831  */
iavf_rx_offset(struct iavf_ring * rx_ring)832 static inline unsigned int iavf_rx_offset(struct iavf_ring *rx_ring)
833 {
834 	return ring_uses_build_skb(rx_ring) ? IAVF_SKB_PAD : 0;
835 }
836 
837 /**
838  * iavf_alloc_mapped_page - recycle or make a new page
839  * @rx_ring: ring to use
840  * @bi: rx_buffer struct to modify
841  *
842  * Returns true if the page was successfully allocated or
843  * reused.
844  **/
iavf_alloc_mapped_page(struct iavf_ring * rx_ring,struct iavf_rx_buffer * bi)845 static bool iavf_alloc_mapped_page(struct iavf_ring *rx_ring,
846 				   struct iavf_rx_buffer *bi)
847 {
848 	struct page *page = bi->page;
849 	dma_addr_t dma;
850 
851 	/* since we are recycling buffers we should seldom need to alloc */
852 	if (likely(page)) {
853 		rx_ring->rx_stats.page_reuse_count++;
854 		return true;
855 	}
856 
857 	/* alloc new page for storage */
858 	page = dev_alloc_pages(iavf_rx_pg_order(rx_ring));
859 	if (unlikely(!page)) {
860 		rx_ring->rx_stats.alloc_page_failed++;
861 		return false;
862 	}
863 
864 	/* map page for use */
865 	dma = dma_map_page_attrs(rx_ring->dev, page, 0,
866 				 iavf_rx_pg_size(rx_ring),
867 				 DMA_FROM_DEVICE,
868 				 IAVF_RX_DMA_ATTR);
869 
870 	/* if mapping failed free memory back to system since
871 	 * there isn't much point in holding memory we can't use
872 	 */
873 	if (dma_mapping_error(rx_ring->dev, dma)) {
874 		__free_pages(page, iavf_rx_pg_order(rx_ring));
875 		rx_ring->rx_stats.alloc_page_failed++;
876 		return false;
877 	}
878 
879 	bi->dma = dma;
880 	bi->page = page;
881 	bi->page_offset = iavf_rx_offset(rx_ring);
882 
883 	/* initialize pagecnt_bias to 1 representing we fully own page */
884 	bi->pagecnt_bias = 1;
885 
886 	return true;
887 }
888 
889 /**
890  * iavf_receive_skb - Send a completed packet up the stack
891  * @rx_ring:  rx ring in play
892  * @skb: packet to send up
893  * @vlan_tag: vlan tag for packet
894  **/
iavf_receive_skb(struct iavf_ring * rx_ring,struct sk_buff * skb,u16 vlan_tag)895 static void iavf_receive_skb(struct iavf_ring *rx_ring,
896 			     struct sk_buff *skb, u16 vlan_tag)
897 {
898 	struct iavf_q_vector *q_vector = rx_ring->q_vector;
899 
900 	if ((rx_ring->netdev->features & NETIF_F_HW_VLAN_CTAG_RX) &&
901 	    (vlan_tag & VLAN_VID_MASK))
902 		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vlan_tag);
903 	else if ((rx_ring->netdev->features & NETIF_F_HW_VLAN_STAG_RX) &&
904 		 vlan_tag & VLAN_VID_MASK)
905 		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021AD), vlan_tag);
906 
907 	napi_gro_receive(&q_vector->napi, skb);
908 }
909 
910 /**
911  * iavf_alloc_rx_buffers - Replace used receive buffers
912  * @rx_ring: ring to place buffers on
913  * @cleaned_count: number of buffers to replace
914  *
915  * Returns false if all allocations were successful, true if any fail
916  **/
iavf_alloc_rx_buffers(struct iavf_ring * rx_ring,u16 cleaned_count)917 bool iavf_alloc_rx_buffers(struct iavf_ring *rx_ring, u16 cleaned_count)
918 {
919 	u16 ntu = rx_ring->next_to_use;
920 	union iavf_rx_desc *rx_desc;
921 	struct iavf_rx_buffer *bi;
922 
923 	/* do nothing if no valid netdev defined */
924 	if (!rx_ring->netdev || !cleaned_count)
925 		return false;
926 
927 	rx_desc = IAVF_RX_DESC(rx_ring, ntu);
928 	bi = &rx_ring->rx_bi[ntu];
929 
930 	do {
931 		if (!iavf_alloc_mapped_page(rx_ring, bi))
932 			goto no_buffers;
933 
934 		/* sync the buffer for use by the device */
935 		dma_sync_single_range_for_device(rx_ring->dev, bi->dma,
936 						 bi->page_offset,
937 						 rx_ring->rx_buf_len,
938 						 DMA_FROM_DEVICE);
939 
940 		/* Refresh the desc even if buffer_addrs didn't change
941 		 * because each write-back erases this info.
942 		 */
943 		rx_desc->read.pkt_addr = cpu_to_le64(bi->dma + bi->page_offset);
944 
945 		rx_desc++;
946 		bi++;
947 		ntu++;
948 		if (unlikely(ntu == rx_ring->count)) {
949 			rx_desc = IAVF_RX_DESC(rx_ring, 0);
950 			bi = rx_ring->rx_bi;
951 			ntu = 0;
952 		}
953 
954 		/* clear the status bits for the next_to_use descriptor */
955 		rx_desc->wb.qword1.status_error_len = 0;
956 
957 		cleaned_count--;
958 	} while (cleaned_count);
959 
960 	if (rx_ring->next_to_use != ntu)
961 		iavf_release_rx_desc(rx_ring, ntu);
962 
963 	return false;
964 
965 no_buffers:
966 	if (rx_ring->next_to_use != ntu)
967 		iavf_release_rx_desc(rx_ring, ntu);
968 
969 	/* make sure to come back via polling to try again after
970 	 * allocation failure
971 	 */
972 	return true;
973 }
974 
975 /**
976  * iavf_rx_checksum - Indicate in skb if hw indicated a good cksum
977  * @vsi: the VSI we care about
978  * @skb: skb currently being received and modified
979  * @rx_desc: the receive descriptor
980  **/
iavf_rx_checksum(struct iavf_vsi * vsi,struct sk_buff * skb,union iavf_rx_desc * rx_desc)981 static inline void iavf_rx_checksum(struct iavf_vsi *vsi,
982 				    struct sk_buff *skb,
983 				    union iavf_rx_desc *rx_desc)
984 {
985 	struct iavf_rx_ptype_decoded decoded;
986 	u32 rx_error, rx_status;
987 	bool ipv4, ipv6;
988 	u8 ptype;
989 	u64 qword;
990 
991 	qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
992 	ptype = (qword & IAVF_RXD_QW1_PTYPE_MASK) >> IAVF_RXD_QW1_PTYPE_SHIFT;
993 	rx_error = (qword & IAVF_RXD_QW1_ERROR_MASK) >>
994 		   IAVF_RXD_QW1_ERROR_SHIFT;
995 	rx_status = (qword & IAVF_RXD_QW1_STATUS_MASK) >>
996 		    IAVF_RXD_QW1_STATUS_SHIFT;
997 	decoded = decode_rx_desc_ptype(ptype);
998 
999 	skb->ip_summed = CHECKSUM_NONE;
1000 
1001 	skb_checksum_none_assert(skb);
1002 
1003 	/* Rx csum enabled and ip headers found? */
1004 	if (!(vsi->netdev->features & NETIF_F_RXCSUM))
1005 		return;
1006 
1007 	/* did the hardware decode the packet and checksum? */
1008 	if (!(rx_status & BIT(IAVF_RX_DESC_STATUS_L3L4P_SHIFT)))
1009 		return;
1010 
1011 	/* both known and outer_ip must be set for the below code to work */
1012 	if (!(decoded.known && decoded.outer_ip))
1013 		return;
1014 
1015 	ipv4 = (decoded.outer_ip == IAVF_RX_PTYPE_OUTER_IP) &&
1016 	       (decoded.outer_ip_ver == IAVF_RX_PTYPE_OUTER_IPV4);
1017 	ipv6 = (decoded.outer_ip == IAVF_RX_PTYPE_OUTER_IP) &&
1018 	       (decoded.outer_ip_ver == IAVF_RX_PTYPE_OUTER_IPV6);
1019 
1020 	if (ipv4 &&
1021 	    (rx_error & (BIT(IAVF_RX_DESC_ERROR_IPE_SHIFT) |
1022 			 BIT(IAVF_RX_DESC_ERROR_EIPE_SHIFT))))
1023 		goto checksum_fail;
1024 
1025 	/* likely incorrect csum if alternate IP extension headers found */
1026 	if (ipv6 &&
1027 	    rx_status & BIT(IAVF_RX_DESC_STATUS_IPV6EXADD_SHIFT))
1028 		/* don't increment checksum err here, non-fatal err */
1029 		return;
1030 
1031 	/* there was some L4 error, count error and punt packet to the stack */
1032 	if (rx_error & BIT(IAVF_RX_DESC_ERROR_L4E_SHIFT))
1033 		goto checksum_fail;
1034 
1035 	/* handle packets that were not able to be checksummed due
1036 	 * to arrival speed, in this case the stack can compute
1037 	 * the csum.
1038 	 */
1039 	if (rx_error & BIT(IAVF_RX_DESC_ERROR_PPRS_SHIFT))
1040 		return;
1041 
1042 	/* Only report checksum unnecessary for TCP, UDP, or SCTP */
1043 	switch (decoded.inner_prot) {
1044 	case IAVF_RX_PTYPE_INNER_PROT_TCP:
1045 	case IAVF_RX_PTYPE_INNER_PROT_UDP:
1046 	case IAVF_RX_PTYPE_INNER_PROT_SCTP:
1047 		skb->ip_summed = CHECKSUM_UNNECESSARY;
1048 		fallthrough;
1049 	default:
1050 		break;
1051 	}
1052 
1053 	return;
1054 
1055 checksum_fail:
1056 	vsi->back->hw_csum_rx_error++;
1057 }
1058 
1059 /**
1060  * iavf_ptype_to_htype - get a hash type
1061  * @ptype: the ptype value from the descriptor
1062  *
1063  * Returns a hash type to be used by skb_set_hash
1064  **/
iavf_ptype_to_htype(u8 ptype)1065 static inline int iavf_ptype_to_htype(u8 ptype)
1066 {
1067 	struct iavf_rx_ptype_decoded decoded = decode_rx_desc_ptype(ptype);
1068 
1069 	if (!decoded.known)
1070 		return PKT_HASH_TYPE_NONE;
1071 
1072 	if (decoded.outer_ip == IAVF_RX_PTYPE_OUTER_IP &&
1073 	    decoded.payload_layer == IAVF_RX_PTYPE_PAYLOAD_LAYER_PAY4)
1074 		return PKT_HASH_TYPE_L4;
1075 	else if (decoded.outer_ip == IAVF_RX_PTYPE_OUTER_IP &&
1076 		 decoded.payload_layer == IAVF_RX_PTYPE_PAYLOAD_LAYER_PAY3)
1077 		return PKT_HASH_TYPE_L3;
1078 	else
1079 		return PKT_HASH_TYPE_L2;
1080 }
1081 
1082 /**
1083  * iavf_rx_hash - set the hash value in the skb
1084  * @ring: descriptor ring
1085  * @rx_desc: specific descriptor
1086  * @skb: skb currently being received and modified
1087  * @rx_ptype: Rx packet type
1088  **/
iavf_rx_hash(struct iavf_ring * ring,union iavf_rx_desc * rx_desc,struct sk_buff * skb,u8 rx_ptype)1089 static inline void iavf_rx_hash(struct iavf_ring *ring,
1090 				union iavf_rx_desc *rx_desc,
1091 				struct sk_buff *skb,
1092 				u8 rx_ptype)
1093 {
1094 	u32 hash;
1095 	const __le64 rss_mask =
1096 		cpu_to_le64((u64)IAVF_RX_DESC_FLTSTAT_RSS_HASH <<
1097 			    IAVF_RX_DESC_STATUS_FLTSTAT_SHIFT);
1098 
1099 	if (ring->netdev->features & NETIF_F_RXHASH)
1100 		return;
1101 
1102 	if ((rx_desc->wb.qword1.status_error_len & rss_mask) == rss_mask) {
1103 		hash = le32_to_cpu(rx_desc->wb.qword0.hi_dword.rss);
1104 		skb_set_hash(skb, hash, iavf_ptype_to_htype(rx_ptype));
1105 	}
1106 }
1107 
1108 /**
1109  * iavf_process_skb_fields - Populate skb header fields from Rx descriptor
1110  * @rx_ring: rx descriptor ring packet is being transacted on
1111  * @rx_desc: pointer to the EOP Rx descriptor
1112  * @skb: pointer to current skb being populated
1113  * @rx_ptype: the packet type decoded by hardware
1114  *
1115  * This function checks the ring, descriptor, and packet information in
1116  * order to populate the hash, checksum, VLAN, protocol, and
1117  * other fields within the skb.
1118  **/
1119 static inline
iavf_process_skb_fields(struct iavf_ring * rx_ring,union iavf_rx_desc * rx_desc,struct sk_buff * skb,u8 rx_ptype)1120 void iavf_process_skb_fields(struct iavf_ring *rx_ring,
1121 			     union iavf_rx_desc *rx_desc, struct sk_buff *skb,
1122 			     u8 rx_ptype)
1123 {
1124 	iavf_rx_hash(rx_ring, rx_desc, skb, rx_ptype);
1125 
1126 	iavf_rx_checksum(rx_ring->vsi, skb, rx_desc);
1127 
1128 	skb_record_rx_queue(skb, rx_ring->queue_index);
1129 
1130 	/* modifies the skb - consumes the enet header */
1131 	skb->protocol = eth_type_trans(skb, rx_ring->netdev);
1132 }
1133 
1134 /**
1135  * iavf_cleanup_headers - Correct empty headers
1136  * @rx_ring: rx descriptor ring packet is being transacted on
1137  * @skb: pointer to current skb being fixed
1138  *
1139  * Also address the case where we are pulling data in on pages only
1140  * and as such no data is present in the skb header.
1141  *
1142  * In addition if skb is not at least 60 bytes we need to pad it so that
1143  * it is large enough to qualify as a valid Ethernet frame.
1144  *
1145  * Returns true if an error was encountered and skb was freed.
1146  **/
iavf_cleanup_headers(struct iavf_ring * rx_ring,struct sk_buff * skb)1147 static bool iavf_cleanup_headers(struct iavf_ring *rx_ring, struct sk_buff *skb)
1148 {
1149 	/* if eth_skb_pad returns an error the skb was freed */
1150 	if (eth_skb_pad(skb))
1151 		return true;
1152 
1153 	return false;
1154 }
1155 
1156 /**
1157  * iavf_reuse_rx_page - page flip buffer and store it back on the ring
1158  * @rx_ring: rx descriptor ring to store buffers on
1159  * @old_buff: donor buffer to have page reused
1160  *
1161  * Synchronizes page for reuse by the adapter
1162  **/
iavf_reuse_rx_page(struct iavf_ring * rx_ring,struct iavf_rx_buffer * old_buff)1163 static void iavf_reuse_rx_page(struct iavf_ring *rx_ring,
1164 			       struct iavf_rx_buffer *old_buff)
1165 {
1166 	struct iavf_rx_buffer *new_buff;
1167 	u16 nta = rx_ring->next_to_alloc;
1168 
1169 	new_buff = &rx_ring->rx_bi[nta];
1170 
1171 	/* update, and store next to alloc */
1172 	nta++;
1173 	rx_ring->next_to_alloc = (nta < rx_ring->count) ? nta : 0;
1174 
1175 	/* transfer page from old buffer to new buffer */
1176 	new_buff->dma		= old_buff->dma;
1177 	new_buff->page		= old_buff->page;
1178 	new_buff->page_offset	= old_buff->page_offset;
1179 	new_buff->pagecnt_bias	= old_buff->pagecnt_bias;
1180 }
1181 
1182 /**
1183  * iavf_can_reuse_rx_page - Determine if this page can be reused by
1184  * the adapter for another receive
1185  *
1186  * @rx_buffer: buffer containing the page
1187  *
1188  * If page is reusable, rx_buffer->page_offset is adjusted to point to
1189  * an unused region in the page.
1190  *
1191  * For small pages, @truesize will be a constant value, half the size
1192  * of the memory at page.  We'll attempt to alternate between high and
1193  * low halves of the page, with one half ready for use by the hardware
1194  * and the other half being consumed by the stack.  We use the page
1195  * ref count to determine whether the stack has finished consuming the
1196  * portion of this page that was passed up with a previous packet.  If
1197  * the page ref count is >1, we'll assume the "other" half page is
1198  * still busy, and this page cannot be reused.
1199  *
1200  * For larger pages, @truesize will be the actual space used by the
1201  * received packet (adjusted upward to an even multiple of the cache
1202  * line size).  This will advance through the page by the amount
1203  * actually consumed by the received packets while there is still
1204  * space for a buffer.  Each region of larger pages will be used at
1205  * most once, after which the page will not be reused.
1206  *
1207  * In either case, if the page is reusable its refcount is increased.
1208  **/
iavf_can_reuse_rx_page(struct iavf_rx_buffer * rx_buffer)1209 static bool iavf_can_reuse_rx_page(struct iavf_rx_buffer *rx_buffer)
1210 {
1211 	unsigned int pagecnt_bias = rx_buffer->pagecnt_bias;
1212 	struct page *page = rx_buffer->page;
1213 
1214 	/* Is any reuse possible? */
1215 	if (!dev_page_is_reusable(page))
1216 		return false;
1217 
1218 #if (PAGE_SIZE < 8192)
1219 	/* if we are only owner of page we can reuse it */
1220 	if (unlikely((page_count(page) - pagecnt_bias) > 1))
1221 		return false;
1222 #else
1223 #define IAVF_LAST_OFFSET \
1224 	(SKB_WITH_OVERHEAD(PAGE_SIZE) - IAVF_RXBUFFER_2048)
1225 	if (rx_buffer->page_offset > IAVF_LAST_OFFSET)
1226 		return false;
1227 #endif
1228 
1229 	/* If we have drained the page fragment pool we need to update
1230 	 * the pagecnt_bias and page count so that we fully restock the
1231 	 * number of references the driver holds.
1232 	 */
1233 	if (unlikely(!pagecnt_bias)) {
1234 		page_ref_add(page, USHRT_MAX);
1235 		rx_buffer->pagecnt_bias = USHRT_MAX;
1236 	}
1237 
1238 	return true;
1239 }
1240 
1241 /**
1242  * iavf_add_rx_frag - Add contents of Rx buffer to sk_buff
1243  * @rx_ring: rx descriptor ring to transact packets on
1244  * @rx_buffer: buffer containing page to add
1245  * @skb: sk_buff to place the data into
1246  * @size: packet length from rx_desc
1247  *
1248  * This function will add the data contained in rx_buffer->page to the skb.
1249  * It will just attach the page as a frag to the skb.
1250  *
1251  * The function will then update the page offset.
1252  **/
iavf_add_rx_frag(struct iavf_ring * rx_ring,struct iavf_rx_buffer * rx_buffer,struct sk_buff * skb,unsigned int size)1253 static void iavf_add_rx_frag(struct iavf_ring *rx_ring,
1254 			     struct iavf_rx_buffer *rx_buffer,
1255 			     struct sk_buff *skb,
1256 			     unsigned int size)
1257 {
1258 #if (PAGE_SIZE < 8192)
1259 	unsigned int truesize = iavf_rx_pg_size(rx_ring) / 2;
1260 #else
1261 	unsigned int truesize = SKB_DATA_ALIGN(size + iavf_rx_offset(rx_ring));
1262 #endif
1263 
1264 	if (!size)
1265 		return;
1266 
1267 	skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buffer->page,
1268 			rx_buffer->page_offset, size, truesize);
1269 
1270 	/* page is being used so we must update the page offset */
1271 #if (PAGE_SIZE < 8192)
1272 	rx_buffer->page_offset ^= truesize;
1273 #else
1274 	rx_buffer->page_offset += truesize;
1275 #endif
1276 }
1277 
1278 /**
1279  * iavf_get_rx_buffer - Fetch Rx buffer and synchronize data for use
1280  * @rx_ring: rx descriptor ring to transact packets on
1281  * @size: size of buffer to add to skb
1282  *
1283  * This function will pull an Rx buffer from the ring and synchronize it
1284  * for use by the CPU.
1285  */
iavf_get_rx_buffer(struct iavf_ring * rx_ring,const unsigned int size)1286 static struct iavf_rx_buffer *iavf_get_rx_buffer(struct iavf_ring *rx_ring,
1287 						 const unsigned int size)
1288 {
1289 	struct iavf_rx_buffer *rx_buffer;
1290 
1291 	rx_buffer = &rx_ring->rx_bi[rx_ring->next_to_clean];
1292 	prefetchw(rx_buffer->page);
1293 	if (!size)
1294 		return rx_buffer;
1295 
1296 	/* we are reusing so sync this buffer for CPU use */
1297 	dma_sync_single_range_for_cpu(rx_ring->dev,
1298 				      rx_buffer->dma,
1299 				      rx_buffer->page_offset,
1300 				      size,
1301 				      DMA_FROM_DEVICE);
1302 
1303 	/* We have pulled a buffer for use, so decrement pagecnt_bias */
1304 	rx_buffer->pagecnt_bias--;
1305 
1306 	return rx_buffer;
1307 }
1308 
1309 /**
1310  * iavf_construct_skb - Allocate skb and populate it
1311  * @rx_ring: rx descriptor ring to transact packets on
1312  * @rx_buffer: rx buffer to pull data from
1313  * @size: size of buffer to add to skb
1314  *
1315  * This function allocates an skb.  It then populates it with the page
1316  * data from the current receive descriptor, taking care to set up the
1317  * skb correctly.
1318  */
iavf_construct_skb(struct iavf_ring * rx_ring,struct iavf_rx_buffer * rx_buffer,unsigned int size)1319 static struct sk_buff *iavf_construct_skb(struct iavf_ring *rx_ring,
1320 					  struct iavf_rx_buffer *rx_buffer,
1321 					  unsigned int size)
1322 {
1323 	void *va;
1324 #if (PAGE_SIZE < 8192)
1325 	unsigned int truesize = iavf_rx_pg_size(rx_ring) / 2;
1326 #else
1327 	unsigned int truesize = SKB_DATA_ALIGN(size);
1328 #endif
1329 	unsigned int headlen;
1330 	struct sk_buff *skb;
1331 
1332 	if (!rx_buffer)
1333 		return NULL;
1334 	/* prefetch first cache line of first page */
1335 	va = page_address(rx_buffer->page) + rx_buffer->page_offset;
1336 	net_prefetch(va);
1337 
1338 	/* allocate a skb to store the frags */
1339 	skb = __napi_alloc_skb(&rx_ring->q_vector->napi,
1340 			       IAVF_RX_HDR_SIZE,
1341 			       GFP_ATOMIC | __GFP_NOWARN);
1342 	if (unlikely(!skb))
1343 		return NULL;
1344 
1345 	/* Determine available headroom for copy */
1346 	headlen = size;
1347 	if (headlen > IAVF_RX_HDR_SIZE)
1348 		headlen = eth_get_headlen(skb->dev, va, IAVF_RX_HDR_SIZE);
1349 
1350 	/* align pull length to size of long to optimize memcpy performance */
1351 	memcpy(__skb_put(skb, headlen), va, ALIGN(headlen, sizeof(long)));
1352 
1353 	/* update all of the pointers */
1354 	size -= headlen;
1355 	if (size) {
1356 		skb_add_rx_frag(skb, 0, rx_buffer->page,
1357 				rx_buffer->page_offset + headlen,
1358 				size, truesize);
1359 
1360 		/* buffer is used by skb, update page_offset */
1361 #if (PAGE_SIZE < 8192)
1362 		rx_buffer->page_offset ^= truesize;
1363 #else
1364 		rx_buffer->page_offset += truesize;
1365 #endif
1366 	} else {
1367 		/* buffer is unused, reset bias back to rx_buffer */
1368 		rx_buffer->pagecnt_bias++;
1369 	}
1370 
1371 	return skb;
1372 }
1373 
1374 /**
1375  * iavf_build_skb - Build skb around an existing buffer
1376  * @rx_ring: Rx descriptor ring to transact packets on
1377  * @rx_buffer: Rx buffer to pull data from
1378  * @size: size of buffer to add to skb
1379  *
1380  * This function builds an skb around an existing Rx buffer, taking care
1381  * to set up the skb correctly and avoid any memcpy overhead.
1382  */
iavf_build_skb(struct iavf_ring * rx_ring,struct iavf_rx_buffer * rx_buffer,unsigned int size)1383 static struct sk_buff *iavf_build_skb(struct iavf_ring *rx_ring,
1384 				      struct iavf_rx_buffer *rx_buffer,
1385 				      unsigned int size)
1386 {
1387 	void *va;
1388 #if (PAGE_SIZE < 8192)
1389 	unsigned int truesize = iavf_rx_pg_size(rx_ring) / 2;
1390 #else
1391 	unsigned int truesize = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) +
1392 				SKB_DATA_ALIGN(IAVF_SKB_PAD + size);
1393 #endif
1394 	struct sk_buff *skb;
1395 
1396 	if (!rx_buffer || !size)
1397 		return NULL;
1398 	/* prefetch first cache line of first page */
1399 	va = page_address(rx_buffer->page) + rx_buffer->page_offset;
1400 	net_prefetch(va);
1401 
1402 	/* build an skb around the page buffer */
1403 	skb = napi_build_skb(va - IAVF_SKB_PAD, truesize);
1404 	if (unlikely(!skb))
1405 		return NULL;
1406 
1407 	/* update pointers within the skb to store the data */
1408 	skb_reserve(skb, IAVF_SKB_PAD);
1409 	__skb_put(skb, size);
1410 
1411 	/* buffer is used by skb, update page_offset */
1412 #if (PAGE_SIZE < 8192)
1413 	rx_buffer->page_offset ^= truesize;
1414 #else
1415 	rx_buffer->page_offset += truesize;
1416 #endif
1417 
1418 	return skb;
1419 }
1420 
1421 /**
1422  * iavf_put_rx_buffer - Clean up used buffer and either recycle or free
1423  * @rx_ring: rx descriptor ring to transact packets on
1424  * @rx_buffer: rx buffer to pull data from
1425  *
1426  * This function will clean up the contents of the rx_buffer.  It will
1427  * either recycle the buffer or unmap it and free the associated resources.
1428  */
iavf_put_rx_buffer(struct iavf_ring * rx_ring,struct iavf_rx_buffer * rx_buffer)1429 static void iavf_put_rx_buffer(struct iavf_ring *rx_ring,
1430 			       struct iavf_rx_buffer *rx_buffer)
1431 {
1432 	if (!rx_buffer)
1433 		return;
1434 
1435 	if (iavf_can_reuse_rx_page(rx_buffer)) {
1436 		/* hand second half of page back to the ring */
1437 		iavf_reuse_rx_page(rx_ring, rx_buffer);
1438 		rx_ring->rx_stats.page_reuse_count++;
1439 	} else {
1440 		/* we are not reusing the buffer so unmap it */
1441 		dma_unmap_page_attrs(rx_ring->dev, rx_buffer->dma,
1442 				     iavf_rx_pg_size(rx_ring),
1443 				     DMA_FROM_DEVICE, IAVF_RX_DMA_ATTR);
1444 		__page_frag_cache_drain(rx_buffer->page,
1445 					rx_buffer->pagecnt_bias);
1446 	}
1447 
1448 	/* clear contents of buffer_info */
1449 	rx_buffer->page = NULL;
1450 }
1451 
1452 /**
1453  * iavf_is_non_eop - process handling of non-EOP buffers
1454  * @rx_ring: Rx ring being processed
1455  * @rx_desc: Rx descriptor for current buffer
1456  * @skb: Current socket buffer containing buffer in progress
1457  *
1458  * This function updates next to clean.  If the buffer is an EOP buffer
1459  * this function exits returning false, otherwise it will place the
1460  * sk_buff in the next buffer to be chained and return true indicating
1461  * that this is in fact a non-EOP buffer.
1462  **/
iavf_is_non_eop(struct iavf_ring * rx_ring,union iavf_rx_desc * rx_desc,struct sk_buff * skb)1463 static bool iavf_is_non_eop(struct iavf_ring *rx_ring,
1464 			    union iavf_rx_desc *rx_desc,
1465 			    struct sk_buff *skb)
1466 {
1467 	u32 ntc = rx_ring->next_to_clean + 1;
1468 
1469 	/* fetch, update, and store next to clean */
1470 	ntc = (ntc < rx_ring->count) ? ntc : 0;
1471 	rx_ring->next_to_clean = ntc;
1472 
1473 	prefetch(IAVF_RX_DESC(rx_ring, ntc));
1474 
1475 	/* if we are the last buffer then there is nothing else to do */
1476 #define IAVF_RXD_EOF BIT(IAVF_RX_DESC_STATUS_EOF_SHIFT)
1477 	if (likely(iavf_test_staterr(rx_desc, IAVF_RXD_EOF)))
1478 		return false;
1479 
1480 	rx_ring->rx_stats.non_eop_descs++;
1481 
1482 	return true;
1483 }
1484 
1485 /**
1486  * iavf_clean_rx_irq - Clean completed descriptors from Rx ring - bounce buf
1487  * @rx_ring: rx descriptor ring to transact packets on
1488  * @budget: Total limit on number of packets to process
1489  *
1490  * This function provides a "bounce buffer" approach to Rx interrupt
1491  * processing.  The advantage to this is that on systems that have
1492  * expensive overhead for IOMMU access this provides a means of avoiding
1493  * it by maintaining the mapping of the page to the system.
1494  *
1495  * Returns amount of work completed
1496  **/
iavf_clean_rx_irq(struct iavf_ring * rx_ring,int budget)1497 static int iavf_clean_rx_irq(struct iavf_ring *rx_ring, int budget)
1498 {
1499 	unsigned int total_rx_bytes = 0, total_rx_packets = 0;
1500 	struct sk_buff *skb = rx_ring->skb;
1501 	u16 cleaned_count = IAVF_DESC_UNUSED(rx_ring);
1502 	bool failure = false;
1503 
1504 	while (likely(total_rx_packets < (unsigned int)budget)) {
1505 		struct iavf_rx_buffer *rx_buffer;
1506 		union iavf_rx_desc *rx_desc;
1507 		unsigned int size;
1508 		u16 vlan_tag = 0;
1509 		u8 rx_ptype;
1510 		u64 qword;
1511 
1512 		/* return some buffers to hardware, one at a time is too slow */
1513 		if (cleaned_count >= IAVF_RX_BUFFER_WRITE) {
1514 			failure = failure ||
1515 				  iavf_alloc_rx_buffers(rx_ring, cleaned_count);
1516 			cleaned_count = 0;
1517 		}
1518 
1519 		rx_desc = IAVF_RX_DESC(rx_ring, rx_ring->next_to_clean);
1520 
1521 		/* status_error_len will always be zero for unused descriptors
1522 		 * because it's cleared in cleanup, and overlaps with hdr_addr
1523 		 * which is always zero because packet split isn't used, if the
1524 		 * hardware wrote DD then the length will be non-zero
1525 		 */
1526 		qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
1527 
1528 		/* This memory barrier is needed to keep us from reading
1529 		 * any other fields out of the rx_desc until we have
1530 		 * verified the descriptor has been written back.
1531 		 */
1532 		dma_rmb();
1533 #define IAVF_RXD_DD BIT(IAVF_RX_DESC_STATUS_DD_SHIFT)
1534 		if (!iavf_test_staterr(rx_desc, IAVF_RXD_DD))
1535 			break;
1536 
1537 		size = (qword & IAVF_RXD_QW1_LENGTH_PBUF_MASK) >>
1538 		       IAVF_RXD_QW1_LENGTH_PBUF_SHIFT;
1539 
1540 		iavf_trace(clean_rx_irq, rx_ring, rx_desc, skb);
1541 		rx_buffer = iavf_get_rx_buffer(rx_ring, size);
1542 
1543 		/* retrieve a buffer from the ring */
1544 		if (skb)
1545 			iavf_add_rx_frag(rx_ring, rx_buffer, skb, size);
1546 		else if (ring_uses_build_skb(rx_ring))
1547 			skb = iavf_build_skb(rx_ring, rx_buffer, size);
1548 		else
1549 			skb = iavf_construct_skb(rx_ring, rx_buffer, size);
1550 
1551 		/* exit if we failed to retrieve a buffer */
1552 		if (!skb) {
1553 			rx_ring->rx_stats.alloc_buff_failed++;
1554 			if (rx_buffer && size)
1555 				rx_buffer->pagecnt_bias++;
1556 			break;
1557 		}
1558 
1559 		iavf_put_rx_buffer(rx_ring, rx_buffer);
1560 		cleaned_count++;
1561 
1562 		if (iavf_is_non_eop(rx_ring, rx_desc, skb))
1563 			continue;
1564 
1565 		/* ERR_MASK will only have valid bits if EOP set, and
1566 		 * what we are doing here is actually checking
1567 		 * IAVF_RX_DESC_ERROR_RXE_SHIFT, since it is the zeroth bit in
1568 		 * the error field
1569 		 */
1570 		if (unlikely(iavf_test_staterr(rx_desc, BIT(IAVF_RXD_QW1_ERROR_SHIFT)))) {
1571 			dev_kfree_skb_any(skb);
1572 			skb = NULL;
1573 			continue;
1574 		}
1575 
1576 		if (iavf_cleanup_headers(rx_ring, skb)) {
1577 			skb = NULL;
1578 			continue;
1579 		}
1580 
1581 		/* probably a little skewed due to removing CRC */
1582 		total_rx_bytes += skb->len;
1583 
1584 		qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
1585 		rx_ptype = (qword & IAVF_RXD_QW1_PTYPE_MASK) >>
1586 			   IAVF_RXD_QW1_PTYPE_SHIFT;
1587 
1588 		/* populate checksum, VLAN, and protocol */
1589 		iavf_process_skb_fields(rx_ring, rx_desc, skb, rx_ptype);
1590 
1591 		if (qword & BIT(IAVF_RX_DESC_STATUS_L2TAG1P_SHIFT) &&
1592 		    rx_ring->flags & IAVF_TXRX_FLAGS_VLAN_TAG_LOC_L2TAG1)
1593 			vlan_tag = le16_to_cpu(rx_desc->wb.qword0.lo_dword.l2tag1);
1594 		if (rx_desc->wb.qword2.ext_status &
1595 		    cpu_to_le16(BIT(IAVF_RX_DESC_EXT_STATUS_L2TAG2P_SHIFT)) &&
1596 		    rx_ring->flags & IAVF_RXR_FLAGS_VLAN_TAG_LOC_L2TAG2_2)
1597 			vlan_tag = le16_to_cpu(rx_desc->wb.qword2.l2tag2_2);
1598 
1599 		iavf_trace(clean_rx_irq_rx, rx_ring, rx_desc, skb);
1600 		iavf_receive_skb(rx_ring, skb, vlan_tag);
1601 		skb = NULL;
1602 
1603 		/* update budget accounting */
1604 		total_rx_packets++;
1605 	}
1606 
1607 	rx_ring->skb = skb;
1608 
1609 	u64_stats_update_begin(&rx_ring->syncp);
1610 	rx_ring->stats.packets += total_rx_packets;
1611 	rx_ring->stats.bytes += total_rx_bytes;
1612 	u64_stats_update_end(&rx_ring->syncp);
1613 	rx_ring->q_vector->rx.total_packets += total_rx_packets;
1614 	rx_ring->q_vector->rx.total_bytes += total_rx_bytes;
1615 
1616 	/* guarantee a trip back through this routine if there was a failure */
1617 	return failure ? budget : (int)total_rx_packets;
1618 }
1619 
iavf_buildreg_itr(const int type,u16 itr)1620 static inline u32 iavf_buildreg_itr(const int type, u16 itr)
1621 {
1622 	u32 val;
1623 
1624 	/* We don't bother with setting the CLEARPBA bit as the data sheet
1625 	 * points out doing so is "meaningless since it was already
1626 	 * auto-cleared". The auto-clearing happens when the interrupt is
1627 	 * asserted.
1628 	 *
1629 	 * Hardware errata 28 for also indicates that writing to a
1630 	 * xxINT_DYN_CTLx CSR with INTENA_MSK (bit 31) set to 0 will clear
1631 	 * an event in the PBA anyway so we need to rely on the automask
1632 	 * to hold pending events for us until the interrupt is re-enabled
1633 	 *
1634 	 * The itr value is reported in microseconds, and the register
1635 	 * value is recorded in 2 microsecond units. For this reason we
1636 	 * only need to shift by the interval shift - 1 instead of the
1637 	 * full value.
1638 	 */
1639 	itr &= IAVF_ITR_MASK;
1640 
1641 	val = IAVF_VFINT_DYN_CTLN1_INTENA_MASK |
1642 	      (type << IAVF_VFINT_DYN_CTLN1_ITR_INDX_SHIFT) |
1643 	      (itr << (IAVF_VFINT_DYN_CTLN1_INTERVAL_SHIFT - 1));
1644 
1645 	return val;
1646 }
1647 
1648 /* a small macro to shorten up some long lines */
1649 #define INTREG IAVF_VFINT_DYN_CTLN1
1650 
1651 /* The act of updating the ITR will cause it to immediately trigger. In order
1652  * to prevent this from throwing off adaptive update statistics we defer the
1653  * update so that it can only happen so often. So after either Tx or Rx are
1654  * updated we make the adaptive scheme wait until either the ITR completely
1655  * expires via the next_update expiration or we have been through at least
1656  * 3 interrupts.
1657  */
1658 #define ITR_COUNTDOWN_START 3
1659 
1660 /**
1661  * iavf_update_enable_itr - Update itr and re-enable MSIX interrupt
1662  * @vsi: the VSI we care about
1663  * @q_vector: q_vector for which itr is being updated and interrupt enabled
1664  *
1665  **/
iavf_update_enable_itr(struct iavf_vsi * vsi,struct iavf_q_vector * q_vector)1666 static inline void iavf_update_enable_itr(struct iavf_vsi *vsi,
1667 					  struct iavf_q_vector *q_vector)
1668 {
1669 	struct iavf_hw *hw = &vsi->back->hw;
1670 	u32 intval;
1671 
1672 	/* These will do nothing if dynamic updates are not enabled */
1673 	iavf_update_itr(q_vector, &q_vector->tx);
1674 	iavf_update_itr(q_vector, &q_vector->rx);
1675 
1676 	/* This block of logic allows us to get away with only updating
1677 	 * one ITR value with each interrupt. The idea is to perform a
1678 	 * pseudo-lazy update with the following criteria.
1679 	 *
1680 	 * 1. Rx is given higher priority than Tx if both are in same state
1681 	 * 2. If we must reduce an ITR that is given highest priority.
1682 	 * 3. We then give priority to increasing ITR based on amount.
1683 	 */
1684 	if (q_vector->rx.target_itr < q_vector->rx.current_itr) {
1685 		/* Rx ITR needs to be reduced, this is highest priority */
1686 		intval = iavf_buildreg_itr(IAVF_RX_ITR,
1687 					   q_vector->rx.target_itr);
1688 		q_vector->rx.current_itr = q_vector->rx.target_itr;
1689 		q_vector->itr_countdown = ITR_COUNTDOWN_START;
1690 	} else if ((q_vector->tx.target_itr < q_vector->tx.current_itr) ||
1691 		   ((q_vector->rx.target_itr - q_vector->rx.current_itr) <
1692 		    (q_vector->tx.target_itr - q_vector->tx.current_itr))) {
1693 		/* Tx ITR needs to be reduced, this is second priority
1694 		 * Tx ITR needs to be increased more than Rx, fourth priority
1695 		 */
1696 		intval = iavf_buildreg_itr(IAVF_TX_ITR,
1697 					   q_vector->tx.target_itr);
1698 		q_vector->tx.current_itr = q_vector->tx.target_itr;
1699 		q_vector->itr_countdown = ITR_COUNTDOWN_START;
1700 	} else if (q_vector->rx.current_itr != q_vector->rx.target_itr) {
1701 		/* Rx ITR needs to be increased, third priority */
1702 		intval = iavf_buildreg_itr(IAVF_RX_ITR,
1703 					   q_vector->rx.target_itr);
1704 		q_vector->rx.current_itr = q_vector->rx.target_itr;
1705 		q_vector->itr_countdown = ITR_COUNTDOWN_START;
1706 	} else {
1707 		/* No ITR update, lowest priority */
1708 		intval = iavf_buildreg_itr(IAVF_ITR_NONE, 0);
1709 		if (q_vector->itr_countdown)
1710 			q_vector->itr_countdown--;
1711 	}
1712 
1713 	if (!test_bit(__IAVF_VSI_DOWN, vsi->state))
1714 		wr32(hw, INTREG(q_vector->reg_idx), intval);
1715 }
1716 
1717 /**
1718  * iavf_napi_poll - NAPI polling Rx/Tx cleanup routine
1719  * @napi: napi struct with our devices info in it
1720  * @budget: amount of work driver is allowed to do this pass, in packets
1721  *
1722  * This function will clean all queues associated with a q_vector.
1723  *
1724  * Returns the amount of work done
1725  **/
iavf_napi_poll(struct napi_struct * napi,int budget)1726 int iavf_napi_poll(struct napi_struct *napi, int budget)
1727 {
1728 	struct iavf_q_vector *q_vector =
1729 			       container_of(napi, struct iavf_q_vector, napi);
1730 	struct iavf_vsi *vsi = q_vector->vsi;
1731 	struct iavf_ring *ring;
1732 	bool clean_complete = true;
1733 	bool arm_wb = false;
1734 	int budget_per_ring;
1735 	int work_done = 0;
1736 
1737 	if (test_bit(__IAVF_VSI_DOWN, vsi->state)) {
1738 		napi_complete(napi);
1739 		return 0;
1740 	}
1741 
1742 	/* Since the actual Tx work is minimal, we can give the Tx a larger
1743 	 * budget and be more aggressive about cleaning up the Tx descriptors.
1744 	 */
1745 	iavf_for_each_ring(ring, q_vector->tx) {
1746 		if (!iavf_clean_tx_irq(vsi, ring, budget)) {
1747 			clean_complete = false;
1748 			continue;
1749 		}
1750 		arm_wb |= ring->arm_wb;
1751 		ring->arm_wb = false;
1752 	}
1753 
1754 	/* Handle case where we are called by netpoll with a budget of 0 */
1755 	if (budget <= 0)
1756 		goto tx_only;
1757 
1758 	/* We attempt to distribute budget to each Rx queue fairly, but don't
1759 	 * allow the budget to go below 1 because that would exit polling early.
1760 	 */
1761 	budget_per_ring = max(budget/q_vector->num_ringpairs, 1);
1762 
1763 	iavf_for_each_ring(ring, q_vector->rx) {
1764 		int cleaned = iavf_clean_rx_irq(ring, budget_per_ring);
1765 
1766 		work_done += cleaned;
1767 		/* if we clean as many as budgeted, we must not be done */
1768 		if (cleaned >= budget_per_ring)
1769 			clean_complete = false;
1770 	}
1771 
1772 	/* If work not completed, return budget and polling will return */
1773 	if (!clean_complete) {
1774 		int cpu_id = smp_processor_id();
1775 
1776 		/* It is possible that the interrupt affinity has changed but,
1777 		 * if the cpu is pegged at 100%, polling will never exit while
1778 		 * traffic continues and the interrupt will be stuck on this
1779 		 * cpu.  We check to make sure affinity is correct before we
1780 		 * continue to poll, otherwise we must stop polling so the
1781 		 * interrupt can move to the correct cpu.
1782 		 */
1783 		if (!cpumask_test_cpu(cpu_id, &q_vector->affinity_mask)) {
1784 			/* Tell napi that we are done polling */
1785 			napi_complete_done(napi, work_done);
1786 
1787 			/* Force an interrupt */
1788 			iavf_force_wb(vsi, q_vector);
1789 
1790 			/* Return budget-1 so that polling stops */
1791 			return budget - 1;
1792 		}
1793 tx_only:
1794 		if (arm_wb) {
1795 			q_vector->tx.ring[0].tx_stats.tx_force_wb++;
1796 			iavf_enable_wb_on_itr(vsi, q_vector);
1797 		}
1798 		return budget;
1799 	}
1800 
1801 	if (vsi->back->flags & IAVF_TXR_FLAGS_WB_ON_ITR)
1802 		q_vector->arm_wb_state = false;
1803 
1804 	/* Exit the polling mode, but don't re-enable interrupts if stack might
1805 	 * poll us due to busy-polling
1806 	 */
1807 	if (likely(napi_complete_done(napi, work_done)))
1808 		iavf_update_enable_itr(vsi, q_vector);
1809 
1810 	return min_t(int, work_done, budget - 1);
1811 }
1812 
1813 /**
1814  * iavf_tx_prepare_vlan_flags - prepare generic TX VLAN tagging flags for HW
1815  * @skb:     send buffer
1816  * @tx_ring: ring to send buffer on
1817  * @flags:   the tx flags to be set
1818  *
1819  * Checks the skb and set up correspondingly several generic transmit flags
1820  * related to VLAN tagging for the HW, such as VLAN, DCB, etc.
1821  *
1822  * Returns error code indicate the frame should be dropped upon error and the
1823  * otherwise  returns 0 to indicate the flags has been set properly.
1824  **/
iavf_tx_prepare_vlan_flags(struct sk_buff * skb,struct iavf_ring * tx_ring,u32 * flags)1825 static void iavf_tx_prepare_vlan_flags(struct sk_buff *skb,
1826 				       struct iavf_ring *tx_ring, u32 *flags)
1827 {
1828 	u32  tx_flags = 0;
1829 
1830 
1831 	/* stack will only request hardware VLAN insertion offload for protocols
1832 	 * that the driver supports and has enabled
1833 	 */
1834 	if (!skb_vlan_tag_present(skb))
1835 		return;
1836 
1837 	tx_flags |= skb_vlan_tag_get(skb) << IAVF_TX_FLAGS_VLAN_SHIFT;
1838 	if (tx_ring->flags & IAVF_TXR_FLAGS_VLAN_TAG_LOC_L2TAG2) {
1839 		tx_flags |= IAVF_TX_FLAGS_HW_OUTER_SINGLE_VLAN;
1840 	} else if (tx_ring->flags & IAVF_TXRX_FLAGS_VLAN_TAG_LOC_L2TAG1) {
1841 		tx_flags |= IAVF_TX_FLAGS_HW_VLAN;
1842 	} else {
1843 		dev_dbg(tx_ring->dev, "Unsupported Tx VLAN tag location requested\n");
1844 		return;
1845 	}
1846 
1847 	*flags = tx_flags;
1848 }
1849 
1850 /**
1851  * iavf_tso - set up the tso context descriptor
1852  * @first:    pointer to first Tx buffer for xmit
1853  * @hdr_len:  ptr to the size of the packet header
1854  * @cd_type_cmd_tso_mss: Quad Word 1
1855  *
1856  * Returns 0 if no TSO can happen, 1 if tso is going, or error
1857  **/
iavf_tso(struct iavf_tx_buffer * first,u8 * hdr_len,u64 * cd_type_cmd_tso_mss)1858 static int iavf_tso(struct iavf_tx_buffer *first, u8 *hdr_len,
1859 		    u64 *cd_type_cmd_tso_mss)
1860 {
1861 	struct sk_buff *skb = first->skb;
1862 	u64 cd_cmd, cd_tso_len, cd_mss;
1863 	union {
1864 		struct iphdr *v4;
1865 		struct ipv6hdr *v6;
1866 		unsigned char *hdr;
1867 	} ip;
1868 	union {
1869 		struct tcphdr *tcp;
1870 		struct udphdr *udp;
1871 		unsigned char *hdr;
1872 	} l4;
1873 	u32 paylen, l4_offset;
1874 	u16 gso_segs, gso_size;
1875 	int err;
1876 
1877 	if (skb->ip_summed != CHECKSUM_PARTIAL)
1878 		return 0;
1879 
1880 	if (!skb_is_gso(skb))
1881 		return 0;
1882 
1883 	err = skb_cow_head(skb, 0);
1884 	if (err < 0)
1885 		return err;
1886 
1887 	ip.hdr = skb_network_header(skb);
1888 	l4.hdr = skb_transport_header(skb);
1889 
1890 	/* initialize outer IP header fields */
1891 	if (ip.v4->version == 4) {
1892 		ip.v4->tot_len = 0;
1893 		ip.v4->check = 0;
1894 	} else {
1895 		ip.v6->payload_len = 0;
1896 	}
1897 
1898 	if (skb_shinfo(skb)->gso_type & (SKB_GSO_GRE |
1899 					 SKB_GSO_GRE_CSUM |
1900 					 SKB_GSO_IPXIP4 |
1901 					 SKB_GSO_IPXIP6 |
1902 					 SKB_GSO_UDP_TUNNEL |
1903 					 SKB_GSO_UDP_TUNNEL_CSUM)) {
1904 		if (!(skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL) &&
1905 		    (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM)) {
1906 			l4.udp->len = 0;
1907 
1908 			/* determine offset of outer transport header */
1909 			l4_offset = l4.hdr - skb->data;
1910 
1911 			/* remove payload length from outer checksum */
1912 			paylen = skb->len - l4_offset;
1913 			csum_replace_by_diff(&l4.udp->check,
1914 					     (__force __wsum)htonl(paylen));
1915 		}
1916 
1917 		/* reset pointers to inner headers */
1918 		ip.hdr = skb_inner_network_header(skb);
1919 		l4.hdr = skb_inner_transport_header(skb);
1920 
1921 		/* initialize inner IP header fields */
1922 		if (ip.v4->version == 4) {
1923 			ip.v4->tot_len = 0;
1924 			ip.v4->check = 0;
1925 		} else {
1926 			ip.v6->payload_len = 0;
1927 		}
1928 	}
1929 
1930 	/* determine offset of inner transport header */
1931 	l4_offset = l4.hdr - skb->data;
1932 	/* remove payload length from inner checksum */
1933 	paylen = skb->len - l4_offset;
1934 
1935 	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) {
1936 		csum_replace_by_diff(&l4.udp->check,
1937 				     (__force __wsum)htonl(paylen));
1938 		/* compute length of UDP segmentation header */
1939 		*hdr_len = (u8)sizeof(l4.udp) + l4_offset;
1940 	} else {
1941 		csum_replace_by_diff(&l4.tcp->check,
1942 				     (__force __wsum)htonl(paylen));
1943 		/* compute length of TCP segmentation header */
1944 		*hdr_len = (u8)((l4.tcp->doff * 4) + l4_offset);
1945 	}
1946 
1947 	/* pull values out of skb_shinfo */
1948 	gso_size = skb_shinfo(skb)->gso_size;
1949 	gso_segs = skb_shinfo(skb)->gso_segs;
1950 
1951 	/* update GSO size and bytecount with header size */
1952 	first->gso_segs = gso_segs;
1953 	first->bytecount += (first->gso_segs - 1) * *hdr_len;
1954 
1955 	/* find the field values */
1956 	cd_cmd = IAVF_TX_CTX_DESC_TSO;
1957 	cd_tso_len = skb->len - *hdr_len;
1958 	cd_mss = gso_size;
1959 	*cd_type_cmd_tso_mss |= (cd_cmd << IAVF_TXD_CTX_QW1_CMD_SHIFT) |
1960 				(cd_tso_len << IAVF_TXD_CTX_QW1_TSO_LEN_SHIFT) |
1961 				(cd_mss << IAVF_TXD_CTX_QW1_MSS_SHIFT);
1962 	return 1;
1963 }
1964 
1965 /**
1966  * iavf_tx_enable_csum - Enable Tx checksum offloads
1967  * @skb: send buffer
1968  * @tx_flags: pointer to Tx flags currently set
1969  * @td_cmd: Tx descriptor command bits to set
1970  * @td_offset: Tx descriptor header offsets to set
1971  * @tx_ring: Tx descriptor ring
1972  * @cd_tunneling: ptr to context desc bits
1973  **/
iavf_tx_enable_csum(struct sk_buff * skb,u32 * tx_flags,u32 * td_cmd,u32 * td_offset,struct iavf_ring * tx_ring,u32 * cd_tunneling)1974 static int iavf_tx_enable_csum(struct sk_buff *skb, u32 *tx_flags,
1975 			       u32 *td_cmd, u32 *td_offset,
1976 			       struct iavf_ring *tx_ring,
1977 			       u32 *cd_tunneling)
1978 {
1979 	union {
1980 		struct iphdr *v4;
1981 		struct ipv6hdr *v6;
1982 		unsigned char *hdr;
1983 	} ip;
1984 	union {
1985 		struct tcphdr *tcp;
1986 		struct udphdr *udp;
1987 		unsigned char *hdr;
1988 	} l4;
1989 	unsigned char *exthdr;
1990 	u32 offset, cmd = 0;
1991 	__be16 frag_off;
1992 	u8 l4_proto = 0;
1993 
1994 	if (skb->ip_summed != CHECKSUM_PARTIAL)
1995 		return 0;
1996 
1997 	ip.hdr = skb_network_header(skb);
1998 	l4.hdr = skb_transport_header(skb);
1999 
2000 	/* compute outer L2 header size */
2001 	offset = ((ip.hdr - skb->data) / 2) << IAVF_TX_DESC_LENGTH_MACLEN_SHIFT;
2002 
2003 	if (skb->encapsulation) {
2004 		u32 tunnel = 0;
2005 		/* define outer network header type */
2006 		if (*tx_flags & IAVF_TX_FLAGS_IPV4) {
2007 			tunnel |= (*tx_flags & IAVF_TX_FLAGS_TSO) ?
2008 				  IAVF_TX_CTX_EXT_IP_IPV4 :
2009 				  IAVF_TX_CTX_EXT_IP_IPV4_NO_CSUM;
2010 
2011 			l4_proto = ip.v4->protocol;
2012 		} else if (*tx_flags & IAVF_TX_FLAGS_IPV6) {
2013 			tunnel |= IAVF_TX_CTX_EXT_IP_IPV6;
2014 
2015 			exthdr = ip.hdr + sizeof(*ip.v6);
2016 			l4_proto = ip.v6->nexthdr;
2017 			if (l4.hdr != exthdr)
2018 				ipv6_skip_exthdr(skb, exthdr - skb->data,
2019 						 &l4_proto, &frag_off);
2020 		}
2021 
2022 		/* define outer transport */
2023 		switch (l4_proto) {
2024 		case IPPROTO_UDP:
2025 			tunnel |= IAVF_TXD_CTX_UDP_TUNNELING;
2026 			*tx_flags |= IAVF_TX_FLAGS_VXLAN_TUNNEL;
2027 			break;
2028 		case IPPROTO_GRE:
2029 			tunnel |= IAVF_TXD_CTX_GRE_TUNNELING;
2030 			*tx_flags |= IAVF_TX_FLAGS_VXLAN_TUNNEL;
2031 			break;
2032 		case IPPROTO_IPIP:
2033 		case IPPROTO_IPV6:
2034 			*tx_flags |= IAVF_TX_FLAGS_VXLAN_TUNNEL;
2035 			l4.hdr = skb_inner_network_header(skb);
2036 			break;
2037 		default:
2038 			if (*tx_flags & IAVF_TX_FLAGS_TSO)
2039 				return -1;
2040 
2041 			skb_checksum_help(skb);
2042 			return 0;
2043 		}
2044 
2045 		/* compute outer L3 header size */
2046 		tunnel |= ((l4.hdr - ip.hdr) / 4) <<
2047 			  IAVF_TXD_CTX_QW0_EXT_IPLEN_SHIFT;
2048 
2049 		/* switch IP header pointer from outer to inner header */
2050 		ip.hdr = skb_inner_network_header(skb);
2051 
2052 		/* compute tunnel header size */
2053 		tunnel |= ((ip.hdr - l4.hdr) / 2) <<
2054 			  IAVF_TXD_CTX_QW0_NATLEN_SHIFT;
2055 
2056 		/* indicate if we need to offload outer UDP header */
2057 		if ((*tx_flags & IAVF_TX_FLAGS_TSO) &&
2058 		    !(skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL) &&
2059 		    (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM))
2060 			tunnel |= IAVF_TXD_CTX_QW0_L4T_CS_MASK;
2061 
2062 		/* record tunnel offload values */
2063 		*cd_tunneling |= tunnel;
2064 
2065 		/* switch L4 header pointer from outer to inner */
2066 		l4.hdr = skb_inner_transport_header(skb);
2067 		l4_proto = 0;
2068 
2069 		/* reset type as we transition from outer to inner headers */
2070 		*tx_flags &= ~(IAVF_TX_FLAGS_IPV4 | IAVF_TX_FLAGS_IPV6);
2071 		if (ip.v4->version == 4)
2072 			*tx_flags |= IAVF_TX_FLAGS_IPV4;
2073 		if (ip.v6->version == 6)
2074 			*tx_flags |= IAVF_TX_FLAGS_IPV6;
2075 	}
2076 
2077 	/* Enable IP checksum offloads */
2078 	if (*tx_flags & IAVF_TX_FLAGS_IPV4) {
2079 		l4_proto = ip.v4->protocol;
2080 		/* the stack computes the IP header already, the only time we
2081 		 * need the hardware to recompute it is in the case of TSO.
2082 		 */
2083 		cmd |= (*tx_flags & IAVF_TX_FLAGS_TSO) ?
2084 		       IAVF_TX_DESC_CMD_IIPT_IPV4_CSUM :
2085 		       IAVF_TX_DESC_CMD_IIPT_IPV4;
2086 	} else if (*tx_flags & IAVF_TX_FLAGS_IPV6) {
2087 		cmd |= IAVF_TX_DESC_CMD_IIPT_IPV6;
2088 
2089 		exthdr = ip.hdr + sizeof(*ip.v6);
2090 		l4_proto = ip.v6->nexthdr;
2091 		if (l4.hdr != exthdr)
2092 			ipv6_skip_exthdr(skb, exthdr - skb->data,
2093 					 &l4_proto, &frag_off);
2094 	}
2095 
2096 	/* compute inner L3 header size */
2097 	offset |= ((l4.hdr - ip.hdr) / 4) << IAVF_TX_DESC_LENGTH_IPLEN_SHIFT;
2098 
2099 	/* Enable L4 checksum offloads */
2100 	switch (l4_proto) {
2101 	case IPPROTO_TCP:
2102 		/* enable checksum offloads */
2103 		cmd |= IAVF_TX_DESC_CMD_L4T_EOFT_TCP;
2104 		offset |= l4.tcp->doff << IAVF_TX_DESC_LENGTH_L4_FC_LEN_SHIFT;
2105 		break;
2106 	case IPPROTO_SCTP:
2107 		/* enable SCTP checksum offload */
2108 		cmd |= IAVF_TX_DESC_CMD_L4T_EOFT_SCTP;
2109 		offset |= (sizeof(struct sctphdr) >> 2) <<
2110 			  IAVF_TX_DESC_LENGTH_L4_FC_LEN_SHIFT;
2111 		break;
2112 	case IPPROTO_UDP:
2113 		/* enable UDP checksum offload */
2114 		cmd |= IAVF_TX_DESC_CMD_L4T_EOFT_UDP;
2115 		offset |= (sizeof(struct udphdr) >> 2) <<
2116 			  IAVF_TX_DESC_LENGTH_L4_FC_LEN_SHIFT;
2117 		break;
2118 	default:
2119 		if (*tx_flags & IAVF_TX_FLAGS_TSO)
2120 			return -1;
2121 		skb_checksum_help(skb);
2122 		return 0;
2123 	}
2124 
2125 	*td_cmd |= cmd;
2126 	*td_offset |= offset;
2127 
2128 	return 1;
2129 }
2130 
2131 /**
2132  * iavf_create_tx_ctx - Build the Tx context descriptor
2133  * @tx_ring:  ring to create the descriptor on
2134  * @cd_type_cmd_tso_mss: Quad Word 1
2135  * @cd_tunneling: Quad Word 0 - bits 0-31
2136  * @cd_l2tag2: Quad Word 0 - bits 32-63
2137  **/
iavf_create_tx_ctx(struct iavf_ring * tx_ring,const u64 cd_type_cmd_tso_mss,const u32 cd_tunneling,const u32 cd_l2tag2)2138 static void iavf_create_tx_ctx(struct iavf_ring *tx_ring,
2139 			       const u64 cd_type_cmd_tso_mss,
2140 			       const u32 cd_tunneling, const u32 cd_l2tag2)
2141 {
2142 	struct iavf_tx_context_desc *context_desc;
2143 	int i = tx_ring->next_to_use;
2144 
2145 	if ((cd_type_cmd_tso_mss == IAVF_TX_DESC_DTYPE_CONTEXT) &&
2146 	    !cd_tunneling && !cd_l2tag2)
2147 		return;
2148 
2149 	/* grab the next descriptor */
2150 	context_desc = IAVF_TX_CTXTDESC(tx_ring, i);
2151 
2152 	i++;
2153 	tx_ring->next_to_use = (i < tx_ring->count) ? i : 0;
2154 
2155 	/* cpu_to_le32 and assign to struct fields */
2156 	context_desc->tunneling_params = cpu_to_le32(cd_tunneling);
2157 	context_desc->l2tag2 = cpu_to_le16(cd_l2tag2);
2158 	context_desc->rsvd = cpu_to_le16(0);
2159 	context_desc->type_cmd_tso_mss = cpu_to_le64(cd_type_cmd_tso_mss);
2160 }
2161 
2162 /**
2163  * __iavf_chk_linearize - Check if there are more than 8 buffers per packet
2164  * @skb:      send buffer
2165  *
2166  * Note: Our HW can't DMA more than 8 buffers to build a packet on the wire
2167  * and so we need to figure out the cases where we need to linearize the skb.
2168  *
2169  * For TSO we need to count the TSO header and segment payload separately.
2170  * As such we need to check cases where we have 7 fragments or more as we
2171  * can potentially require 9 DMA transactions, 1 for the TSO header, 1 for
2172  * the segment payload in the first descriptor, and another 7 for the
2173  * fragments.
2174  **/
__iavf_chk_linearize(struct sk_buff * skb)2175 bool __iavf_chk_linearize(struct sk_buff *skb)
2176 {
2177 	const skb_frag_t *frag, *stale;
2178 	int nr_frags, sum;
2179 
2180 	/* no need to check if number of frags is less than 7 */
2181 	nr_frags = skb_shinfo(skb)->nr_frags;
2182 	if (nr_frags < (IAVF_MAX_BUFFER_TXD - 1))
2183 		return false;
2184 
2185 	/* We need to walk through the list and validate that each group
2186 	 * of 6 fragments totals at least gso_size.
2187 	 */
2188 	nr_frags -= IAVF_MAX_BUFFER_TXD - 2;
2189 	frag = &skb_shinfo(skb)->frags[0];
2190 
2191 	/* Initialize size to the negative value of gso_size minus 1.  We
2192 	 * use this as the worst case scenerio in which the frag ahead
2193 	 * of us only provides one byte which is why we are limited to 6
2194 	 * descriptors for a single transmit as the header and previous
2195 	 * fragment are already consuming 2 descriptors.
2196 	 */
2197 	sum = 1 - skb_shinfo(skb)->gso_size;
2198 
2199 	/* Add size of frags 0 through 4 to create our initial sum */
2200 	sum += skb_frag_size(frag++);
2201 	sum += skb_frag_size(frag++);
2202 	sum += skb_frag_size(frag++);
2203 	sum += skb_frag_size(frag++);
2204 	sum += skb_frag_size(frag++);
2205 
2206 	/* Walk through fragments adding latest fragment, testing it, and
2207 	 * then removing stale fragments from the sum.
2208 	 */
2209 	for (stale = &skb_shinfo(skb)->frags[0];; stale++) {
2210 		int stale_size = skb_frag_size(stale);
2211 
2212 		sum += skb_frag_size(frag++);
2213 
2214 		/* The stale fragment may present us with a smaller
2215 		 * descriptor than the actual fragment size. To account
2216 		 * for that we need to remove all the data on the front and
2217 		 * figure out what the remainder would be in the last
2218 		 * descriptor associated with the fragment.
2219 		 */
2220 		if (stale_size > IAVF_MAX_DATA_PER_TXD) {
2221 			int align_pad = -(skb_frag_off(stale)) &
2222 					(IAVF_MAX_READ_REQ_SIZE - 1);
2223 
2224 			sum -= align_pad;
2225 			stale_size -= align_pad;
2226 
2227 			do {
2228 				sum -= IAVF_MAX_DATA_PER_TXD_ALIGNED;
2229 				stale_size -= IAVF_MAX_DATA_PER_TXD_ALIGNED;
2230 			} while (stale_size > IAVF_MAX_DATA_PER_TXD);
2231 		}
2232 
2233 		/* if sum is negative we failed to make sufficient progress */
2234 		if (sum < 0)
2235 			return true;
2236 
2237 		if (!nr_frags--)
2238 			break;
2239 
2240 		sum -= stale_size;
2241 	}
2242 
2243 	return false;
2244 }
2245 
2246 /**
2247  * __iavf_maybe_stop_tx - 2nd level check for tx stop conditions
2248  * @tx_ring: the ring to be checked
2249  * @size:    the size buffer we want to assure is available
2250  *
2251  * Returns -EBUSY if a stop is needed, else 0
2252  **/
__iavf_maybe_stop_tx(struct iavf_ring * tx_ring,int size)2253 int __iavf_maybe_stop_tx(struct iavf_ring *tx_ring, int size)
2254 {
2255 	netif_stop_subqueue(tx_ring->netdev, tx_ring->queue_index);
2256 	/* Memory barrier before checking head and tail */
2257 	smp_mb();
2258 
2259 	/* Check again in a case another CPU has just made room available. */
2260 	if (likely(IAVF_DESC_UNUSED(tx_ring) < size))
2261 		return -EBUSY;
2262 
2263 	/* A reprieve! - use start_queue because it doesn't call schedule */
2264 	netif_start_subqueue(tx_ring->netdev, tx_ring->queue_index);
2265 	++tx_ring->tx_stats.restart_queue;
2266 	return 0;
2267 }
2268 
2269 /**
2270  * iavf_tx_map - Build the Tx descriptor
2271  * @tx_ring:  ring to send buffer on
2272  * @skb:      send buffer
2273  * @first:    first buffer info buffer to use
2274  * @tx_flags: collected send information
2275  * @hdr_len:  size of the packet header
2276  * @td_cmd:   the command field in the descriptor
2277  * @td_offset: offset for checksum or crc
2278  **/
iavf_tx_map(struct iavf_ring * tx_ring,struct sk_buff * skb,struct iavf_tx_buffer * first,u32 tx_flags,const u8 hdr_len,u32 td_cmd,u32 td_offset)2279 static inline void iavf_tx_map(struct iavf_ring *tx_ring, struct sk_buff *skb,
2280 			       struct iavf_tx_buffer *first, u32 tx_flags,
2281 			       const u8 hdr_len, u32 td_cmd, u32 td_offset)
2282 {
2283 	unsigned int data_len = skb->data_len;
2284 	unsigned int size = skb_headlen(skb);
2285 	skb_frag_t *frag;
2286 	struct iavf_tx_buffer *tx_bi;
2287 	struct iavf_tx_desc *tx_desc;
2288 	u16 i = tx_ring->next_to_use;
2289 	u32 td_tag = 0;
2290 	dma_addr_t dma;
2291 
2292 	if (tx_flags & IAVF_TX_FLAGS_HW_VLAN) {
2293 		td_cmd |= IAVF_TX_DESC_CMD_IL2TAG1;
2294 		td_tag = (tx_flags & IAVF_TX_FLAGS_VLAN_MASK) >>
2295 			 IAVF_TX_FLAGS_VLAN_SHIFT;
2296 	}
2297 
2298 	first->tx_flags = tx_flags;
2299 
2300 	dma = dma_map_single(tx_ring->dev, skb->data, size, DMA_TO_DEVICE);
2301 
2302 	tx_desc = IAVF_TX_DESC(tx_ring, i);
2303 	tx_bi = first;
2304 
2305 	for (frag = &skb_shinfo(skb)->frags[0];; frag++) {
2306 		unsigned int max_data = IAVF_MAX_DATA_PER_TXD_ALIGNED;
2307 
2308 		if (dma_mapping_error(tx_ring->dev, dma))
2309 			goto dma_error;
2310 
2311 		/* record length, and DMA address */
2312 		dma_unmap_len_set(tx_bi, len, size);
2313 		dma_unmap_addr_set(tx_bi, dma, dma);
2314 
2315 		/* align size to end of page */
2316 		max_data += -dma & (IAVF_MAX_READ_REQ_SIZE - 1);
2317 		tx_desc->buffer_addr = cpu_to_le64(dma);
2318 
2319 		while (unlikely(size > IAVF_MAX_DATA_PER_TXD)) {
2320 			tx_desc->cmd_type_offset_bsz =
2321 				build_ctob(td_cmd, td_offset,
2322 					   max_data, td_tag);
2323 
2324 			tx_desc++;
2325 			i++;
2326 
2327 			if (i == tx_ring->count) {
2328 				tx_desc = IAVF_TX_DESC(tx_ring, 0);
2329 				i = 0;
2330 			}
2331 
2332 			dma += max_data;
2333 			size -= max_data;
2334 
2335 			max_data = IAVF_MAX_DATA_PER_TXD_ALIGNED;
2336 			tx_desc->buffer_addr = cpu_to_le64(dma);
2337 		}
2338 
2339 		if (likely(!data_len))
2340 			break;
2341 
2342 		tx_desc->cmd_type_offset_bsz = build_ctob(td_cmd, td_offset,
2343 							  size, td_tag);
2344 
2345 		tx_desc++;
2346 		i++;
2347 
2348 		if (i == tx_ring->count) {
2349 			tx_desc = IAVF_TX_DESC(tx_ring, 0);
2350 			i = 0;
2351 		}
2352 
2353 		size = skb_frag_size(frag);
2354 		data_len -= size;
2355 
2356 		dma = skb_frag_dma_map(tx_ring->dev, frag, 0, size,
2357 				       DMA_TO_DEVICE);
2358 
2359 		tx_bi = &tx_ring->tx_bi[i];
2360 	}
2361 
2362 	netdev_tx_sent_queue(txring_txq(tx_ring), first->bytecount);
2363 
2364 	i++;
2365 	if (i == tx_ring->count)
2366 		i = 0;
2367 
2368 	tx_ring->next_to_use = i;
2369 
2370 	iavf_maybe_stop_tx(tx_ring, DESC_NEEDED);
2371 
2372 	/* write last descriptor with RS and EOP bits */
2373 	td_cmd |= IAVF_TXD_CMD;
2374 	tx_desc->cmd_type_offset_bsz =
2375 			build_ctob(td_cmd, td_offset, size, td_tag);
2376 
2377 	skb_tx_timestamp(skb);
2378 
2379 	/* Force memory writes to complete before letting h/w know there
2380 	 * are new descriptors to fetch.
2381 	 *
2382 	 * We also use this memory barrier to make certain all of the
2383 	 * status bits have been updated before next_to_watch is written.
2384 	 */
2385 	wmb();
2386 
2387 	/* set next_to_watch value indicating a packet is present */
2388 	first->next_to_watch = tx_desc;
2389 
2390 	/* notify HW of packet */
2391 	if (netif_xmit_stopped(txring_txq(tx_ring)) || !netdev_xmit_more()) {
2392 		writel(i, tx_ring->tail);
2393 	}
2394 
2395 	return;
2396 
2397 dma_error:
2398 	dev_info(tx_ring->dev, "TX DMA map failed\n");
2399 
2400 	/* clear dma mappings for failed tx_bi map */
2401 	for (;;) {
2402 		tx_bi = &tx_ring->tx_bi[i];
2403 		iavf_unmap_and_free_tx_resource(tx_ring, tx_bi);
2404 		if (tx_bi == first)
2405 			break;
2406 		if (i == 0)
2407 			i = tx_ring->count;
2408 		i--;
2409 	}
2410 
2411 	tx_ring->next_to_use = i;
2412 }
2413 
2414 /**
2415  * iavf_xmit_frame_ring - Sends buffer on Tx ring
2416  * @skb:     send buffer
2417  * @tx_ring: ring to send buffer on
2418  *
2419  * Returns NETDEV_TX_OK if sent, else an error code
2420  **/
iavf_xmit_frame_ring(struct sk_buff * skb,struct iavf_ring * tx_ring)2421 static netdev_tx_t iavf_xmit_frame_ring(struct sk_buff *skb,
2422 					struct iavf_ring *tx_ring)
2423 {
2424 	u64 cd_type_cmd_tso_mss = IAVF_TX_DESC_DTYPE_CONTEXT;
2425 	u32 cd_tunneling = 0, cd_l2tag2 = 0;
2426 	struct iavf_tx_buffer *first;
2427 	u32 td_offset = 0;
2428 	u32 tx_flags = 0;
2429 	__be16 protocol;
2430 	u32 td_cmd = 0;
2431 	u8 hdr_len = 0;
2432 	int tso, count;
2433 
2434 	/* prefetch the data, we'll need it later */
2435 	prefetch(skb->data);
2436 
2437 	iavf_trace(xmit_frame_ring, skb, tx_ring);
2438 
2439 	count = iavf_xmit_descriptor_count(skb);
2440 	if (iavf_chk_linearize(skb, count)) {
2441 		if (__skb_linearize(skb)) {
2442 			dev_kfree_skb_any(skb);
2443 			return NETDEV_TX_OK;
2444 		}
2445 		count = iavf_txd_use_count(skb->len);
2446 		tx_ring->tx_stats.tx_linearize++;
2447 	}
2448 
2449 	/* need: 1 descriptor per page * PAGE_SIZE/IAVF_MAX_DATA_PER_TXD,
2450 	 *       + 1 desc for skb_head_len/IAVF_MAX_DATA_PER_TXD,
2451 	 *       + 4 desc gap to avoid the cache line where head is,
2452 	 *       + 1 desc for context descriptor,
2453 	 * otherwise try next time
2454 	 */
2455 	if (iavf_maybe_stop_tx(tx_ring, count + 4 + 1)) {
2456 		tx_ring->tx_stats.tx_busy++;
2457 		return NETDEV_TX_BUSY;
2458 	}
2459 
2460 	/* record the location of the first descriptor for this packet */
2461 	first = &tx_ring->tx_bi[tx_ring->next_to_use];
2462 	first->skb = skb;
2463 	first->bytecount = skb->len;
2464 	first->gso_segs = 1;
2465 
2466 	/* prepare the xmit flags */
2467 	iavf_tx_prepare_vlan_flags(skb, tx_ring, &tx_flags);
2468 	if (tx_flags & IAVF_TX_FLAGS_HW_OUTER_SINGLE_VLAN) {
2469 		cd_type_cmd_tso_mss |= IAVF_TX_CTX_DESC_IL2TAG2 <<
2470 			IAVF_TXD_CTX_QW1_CMD_SHIFT;
2471 		cd_l2tag2 = (tx_flags & IAVF_TX_FLAGS_VLAN_MASK) >>
2472 			IAVF_TX_FLAGS_VLAN_SHIFT;
2473 	}
2474 
2475 	/* obtain protocol of skb */
2476 	protocol = vlan_get_protocol(skb);
2477 
2478 	/* setup IPv4/IPv6 offloads */
2479 	if (protocol == htons(ETH_P_IP))
2480 		tx_flags |= IAVF_TX_FLAGS_IPV4;
2481 	else if (protocol == htons(ETH_P_IPV6))
2482 		tx_flags |= IAVF_TX_FLAGS_IPV6;
2483 
2484 	tso = iavf_tso(first, &hdr_len, &cd_type_cmd_tso_mss);
2485 
2486 	if (tso < 0)
2487 		goto out_drop;
2488 	else if (tso)
2489 		tx_flags |= IAVF_TX_FLAGS_TSO;
2490 
2491 	/* Always offload the checksum, since it's in the data descriptor */
2492 	tso = iavf_tx_enable_csum(skb, &tx_flags, &td_cmd, &td_offset,
2493 				  tx_ring, &cd_tunneling);
2494 	if (tso < 0)
2495 		goto out_drop;
2496 
2497 	/* always enable CRC insertion offload */
2498 	td_cmd |= IAVF_TX_DESC_CMD_ICRC;
2499 
2500 	iavf_create_tx_ctx(tx_ring, cd_type_cmd_tso_mss,
2501 			   cd_tunneling, cd_l2tag2);
2502 
2503 	iavf_tx_map(tx_ring, skb, first, tx_flags, hdr_len,
2504 		    td_cmd, td_offset);
2505 
2506 	return NETDEV_TX_OK;
2507 
2508 out_drop:
2509 	iavf_trace(xmit_frame_ring_drop, first->skb, tx_ring);
2510 	dev_kfree_skb_any(first->skb);
2511 	first->skb = NULL;
2512 	return NETDEV_TX_OK;
2513 }
2514 
2515 /**
2516  * iavf_xmit_frame - Selects the correct VSI and Tx queue to send buffer
2517  * @skb:    send buffer
2518  * @netdev: network interface device structure
2519  *
2520  * Returns NETDEV_TX_OK if sent, else an error code
2521  **/
iavf_xmit_frame(struct sk_buff * skb,struct net_device * netdev)2522 netdev_tx_t iavf_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
2523 {
2524 	struct iavf_adapter *adapter = netdev_priv(netdev);
2525 	struct iavf_ring *tx_ring = &adapter->tx_rings[skb->queue_mapping];
2526 
2527 	/* hardware can't handle really short frames, hardware padding works
2528 	 * beyond this point
2529 	 */
2530 	if (unlikely(skb->len < IAVF_MIN_TX_LEN)) {
2531 		if (skb_pad(skb, IAVF_MIN_TX_LEN - skb->len))
2532 			return NETDEV_TX_OK;
2533 		skb->len = IAVF_MIN_TX_LEN;
2534 		skb_set_tail_pointer(skb, IAVF_MIN_TX_LEN);
2535 	}
2536 
2537 	return iavf_xmit_frame_ring(skb, tx_ring);
2538 }
2539