xref: /freebsd/sys/dev/sfxge/sfxge_tx.c (revision 56e53cb8ef000c3ef72337a4095987a932cdedef)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2010-2016 Solarflare Communications Inc.
5  * All rights reserved.
6  *
7  * This software was developed in part by Philip Paeps under contract for
8  * Solarflare Communications, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright notice,
14  *    this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright notice,
16  *    this list of conditions and the following disclaimer in the documentation
17  *    and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
20  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
26  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
27  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
28  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
29  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  *
31  * The views and conclusions contained in the software and documentation are
32  * those of the authors and should not be interpreted as representing official
33  * policies, either expressed or implied, of the FreeBSD Project.
34  */
35 
36 /* Theory of operation:
37  *
38  * Tx queues allocation and mapping
39  *
40  * One Tx queue with enabled checksum offload is allocated per Rx channel
41  * (event queue).  Also 2 Tx queues (one without checksum offload and one
42  * with IP checksum offload only) are allocated and bound to event queue 0.
43  * sfxge_txq_type is used as Tx queue label.
44  *
45  * So, event queue plus label mapping to Tx queue index is:
46  *	if event queue index is 0, TxQ-index = TxQ-label * [0..SFXGE_TXQ_NTYPES)
47  *	else TxQ-index = SFXGE_TXQ_NTYPES + EvQ-index - 1
48  * See sfxge_get_txq_by_label() sfxge_ev.c
49  */
50 
51 #include <sys/cdefs.h>
52 __FBSDID("$FreeBSD$");
53 
54 #include "opt_rss.h"
55 
56 #include <sys/param.h>
57 #include <sys/malloc.h>
58 #include <sys/mbuf.h>
59 #include <sys/smp.h>
60 #include <sys/socket.h>
61 #include <sys/sysctl.h>
62 #include <sys/syslog.h>
63 #include <sys/limits.h>
64 
65 #include <net/bpf.h>
66 #include <net/ethernet.h>
67 #include <net/if.h>
68 #include <net/if_vlan_var.h>
69 
70 #include <netinet/in.h>
71 #include <netinet/ip.h>
72 #include <netinet/ip6.h>
73 #include <netinet/tcp.h>
74 
75 #ifdef RSS
76 #include <net/rss_config.h>
77 #endif
78 
79 #include "common/efx.h"
80 
81 #include "sfxge.h"
82 #include "sfxge_tx.h"
83 
84 
85 #define	SFXGE_PARAM_TX_DPL_GET_MAX	SFXGE_PARAM(tx_dpl_get_max)
86 static int sfxge_tx_dpl_get_max = SFXGE_TX_DPL_GET_PKT_LIMIT_DEFAULT;
87 TUNABLE_INT(SFXGE_PARAM_TX_DPL_GET_MAX, &sfxge_tx_dpl_get_max);
88 SYSCTL_INT(_hw_sfxge, OID_AUTO, tx_dpl_get_max, CTLFLAG_RDTUN,
89 	   &sfxge_tx_dpl_get_max, 0,
90 	   "Maximum number of any packets in deferred packet get-list");
91 
92 #define	SFXGE_PARAM_TX_DPL_GET_NON_TCP_MAX \
93 	SFXGE_PARAM(tx_dpl_get_non_tcp_max)
94 static int sfxge_tx_dpl_get_non_tcp_max =
95 	SFXGE_TX_DPL_GET_NON_TCP_PKT_LIMIT_DEFAULT;
96 TUNABLE_INT(SFXGE_PARAM_TX_DPL_GET_NON_TCP_MAX, &sfxge_tx_dpl_get_non_tcp_max);
97 SYSCTL_INT(_hw_sfxge, OID_AUTO, tx_dpl_get_non_tcp_max, CTLFLAG_RDTUN,
98 	   &sfxge_tx_dpl_get_non_tcp_max, 0,
99 	   "Maximum number of non-TCP packets in deferred packet get-list");
100 
101 #define	SFXGE_PARAM_TX_DPL_PUT_MAX	SFXGE_PARAM(tx_dpl_put_max)
102 static int sfxge_tx_dpl_put_max = SFXGE_TX_DPL_PUT_PKT_LIMIT_DEFAULT;
103 TUNABLE_INT(SFXGE_PARAM_TX_DPL_PUT_MAX, &sfxge_tx_dpl_put_max);
104 SYSCTL_INT(_hw_sfxge, OID_AUTO, tx_dpl_put_max, CTLFLAG_RDTUN,
105 	   &sfxge_tx_dpl_put_max, 0,
106 	   "Maximum number of any packets in deferred packet put-list");
107 
108 #define	SFXGE_PARAM_TSO_FW_ASSISTED	SFXGE_PARAM(tso_fw_assisted)
109 static int sfxge_tso_fw_assisted = (SFXGE_FATSOV1 | SFXGE_FATSOV2);
110 TUNABLE_INT(SFXGE_PARAM_TSO_FW_ASSISTED, &sfxge_tso_fw_assisted);
111 SYSCTL_INT(_hw_sfxge, OID_AUTO, tso_fw_assisted, CTLFLAG_RDTUN,
112 	   &sfxge_tso_fw_assisted, 0,
113 	   "Bitmask of FW-assisted TSO allowed to use if supported by NIC firmware");
114 
115 
116 static const struct {
117 	const char *name;
118 	size_t offset;
119 } sfxge_tx_stats[] = {
120 #define	SFXGE_TX_STAT(name, member) \
121 	{ #name, offsetof(struct sfxge_txq, member) }
122 	SFXGE_TX_STAT(tso_bursts, tso_bursts),
123 	SFXGE_TX_STAT(tso_packets, tso_packets),
124 	SFXGE_TX_STAT(tso_long_headers, tso_long_headers),
125 	SFXGE_TX_STAT(tso_pdrop_too_many, tso_pdrop_too_many),
126 	SFXGE_TX_STAT(tso_pdrop_no_rsrc, tso_pdrop_no_rsrc),
127 	SFXGE_TX_STAT(tx_collapses, collapses),
128 	SFXGE_TX_STAT(tx_drops, drops),
129 	SFXGE_TX_STAT(tx_get_overflow, get_overflow),
130 	SFXGE_TX_STAT(tx_get_non_tcp_overflow, get_non_tcp_overflow),
131 	SFXGE_TX_STAT(tx_put_overflow, put_overflow),
132 	SFXGE_TX_STAT(tx_netdown_drops, netdown_drops),
133 };
134 
135 
136 /* Forward declarations. */
137 static void sfxge_tx_qdpl_service(struct sfxge_txq *txq);
138 static void sfxge_tx_qlist_post(struct sfxge_txq *txq);
139 static void sfxge_tx_qunblock(struct sfxge_txq *txq);
140 static int sfxge_tx_queue_tso(struct sfxge_txq *txq, struct mbuf *mbuf,
141 			      const bus_dma_segment_t *dma_seg, int n_dma_seg,
142 			      int vlan_tagged);
143 
144 static int
145 sfxge_tx_maybe_insert_tag(struct sfxge_txq *txq, struct mbuf *mbuf)
146 {
147 	uint16_t this_tag = ((mbuf->m_flags & M_VLANTAG) ?
148 			     mbuf->m_pkthdr.ether_vtag :
149 			     0);
150 
151 	if (this_tag == txq->hw_vlan_tci)
152 		return (0);
153 
154 	efx_tx_qdesc_vlantci_create(txq->common,
155 				    bswap16(this_tag),
156 				    &txq->pend_desc[0]);
157 	txq->n_pend_desc = 1;
158 	txq->hw_vlan_tci = this_tag;
159 	return (1);
160 }
161 
162 static inline void
163 sfxge_next_stmp(struct sfxge_txq *txq, struct sfxge_tx_mapping **pstmp)
164 {
165 	KASSERT((*pstmp)->flags == 0, ("stmp flags are not 0"));
166 	if (__predict_false(*pstmp ==
167 			    &txq->stmp[txq->ptr_mask]))
168 		*pstmp = &txq->stmp[0];
169 	else
170 		(*pstmp)++;
171 }
172 
173 
174 void
175 sfxge_tx_qcomplete(struct sfxge_txq *txq, struct sfxge_evq *evq)
176 {
177 	unsigned int completed;
178 
179 	SFXGE_EVQ_LOCK_ASSERT_OWNED(evq);
180 
181 	completed = txq->completed;
182 	while (completed != txq->pending) {
183 		struct sfxge_tx_mapping *stmp;
184 		unsigned int id;
185 
186 		id = completed++ & txq->ptr_mask;
187 
188 		stmp = &txq->stmp[id];
189 		if (stmp->flags & TX_BUF_UNMAP) {
190 			bus_dmamap_unload(txq->packet_dma_tag, stmp->map);
191 			if (stmp->flags & TX_BUF_MBUF) {
192 				struct mbuf *m = stmp->u.mbuf;
193 				do
194 					m = m_free(m);
195 				while (m != NULL);
196 			} else {
197 				free(stmp->u.heap_buf, M_SFXGE);
198 			}
199 			stmp->flags = 0;
200 		}
201 	}
202 	txq->completed = completed;
203 
204 	/* Check whether we need to unblock the queue. */
205 	mb();
206 	if (txq->blocked) {
207 		unsigned int level;
208 
209 		level = txq->added - txq->completed;
210 		if (level <= SFXGE_TXQ_UNBLOCK_LEVEL(txq->entries))
211 			sfxge_tx_qunblock(txq);
212 	}
213 }
214 
215 static unsigned int
216 sfxge_is_mbuf_non_tcp(struct mbuf *mbuf)
217 {
218 	/* Absence of TCP checksum flags does not mean that it is non-TCP
219 	 * but it should be true if user wants to achieve high throughput.
220 	 */
221 	return (!(mbuf->m_pkthdr.csum_flags & (CSUM_IP_TCP | CSUM_IP6_TCP)));
222 }
223 
224 /*
225  * Reorder the put list and append it to the get list.
226  */
227 static void
228 sfxge_tx_qdpl_swizzle(struct sfxge_txq *txq)
229 {
230 	struct sfxge_tx_dpl *stdp;
231 	struct mbuf *mbuf, *get_next, **get_tailp;
232 	volatile uintptr_t *putp;
233 	uintptr_t put;
234 	unsigned int count;
235 	unsigned int non_tcp_count;
236 
237 	SFXGE_TXQ_LOCK_ASSERT_OWNED(txq);
238 
239 	stdp = &txq->dpl;
240 
241 	/* Acquire the put list. */
242 	putp = &stdp->std_put;
243 	put = atomic_readandclear_ptr(putp);
244 	mbuf = (void *)put;
245 
246 	if (mbuf == NULL)
247 		return;
248 
249 	/* Reverse the put list. */
250 	get_tailp = &mbuf->m_nextpkt;
251 	get_next = NULL;
252 
253 	count = 0;
254 	non_tcp_count = 0;
255 	do {
256 		struct mbuf *put_next;
257 
258 		non_tcp_count += sfxge_is_mbuf_non_tcp(mbuf);
259 		put_next = mbuf->m_nextpkt;
260 		mbuf->m_nextpkt = get_next;
261 		get_next = mbuf;
262 		mbuf = put_next;
263 
264 		count++;
265 	} while (mbuf != NULL);
266 
267 	if (count > stdp->std_put_hiwat)
268 		stdp->std_put_hiwat = count;
269 
270 	/* Append the reversed put list to the get list. */
271 	KASSERT(*get_tailp == NULL, ("*get_tailp != NULL"));
272 	*stdp->std_getp = get_next;
273 	stdp->std_getp = get_tailp;
274 	stdp->std_get_count += count;
275 	stdp->std_get_non_tcp_count += non_tcp_count;
276 }
277 
278 static void
279 sfxge_tx_qreap(struct sfxge_txq *txq)
280 {
281 	SFXGE_TXQ_LOCK_ASSERT_OWNED(txq);
282 
283 	txq->reaped = txq->completed;
284 }
285 
286 static void
287 sfxge_tx_qlist_post(struct sfxge_txq *txq)
288 {
289 	unsigned int old_added;
290 	unsigned int block_level;
291 	unsigned int level;
292 	int rc;
293 
294 	SFXGE_TXQ_LOCK_ASSERT_OWNED(txq);
295 
296 	KASSERT(txq->n_pend_desc != 0, ("txq->n_pend_desc == 0"));
297 	KASSERT(txq->n_pend_desc <= txq->max_pkt_desc,
298 		("txq->n_pend_desc too large"));
299 	KASSERT(!txq->blocked, ("txq->blocked"));
300 
301 	old_added = txq->added;
302 
303 	/* Post the fragment list. */
304 	rc = efx_tx_qdesc_post(txq->common, txq->pend_desc, txq->n_pend_desc,
305 			  txq->reaped, &txq->added);
306 	KASSERT(rc == 0, ("efx_tx_qdesc_post() failed"));
307 
308 	/* If efx_tx_qdesc_post() had to refragment, our information about
309 	 * buffers to free may be associated with the wrong
310 	 * descriptors.
311 	 */
312 	KASSERT(txq->added - old_added == txq->n_pend_desc,
313 		("efx_tx_qdesc_post() refragmented descriptors"));
314 
315 	level = txq->added - txq->reaped;
316 	KASSERT(level <= txq->entries, ("overfilled TX queue"));
317 
318 	/* Clear the fragment list. */
319 	txq->n_pend_desc = 0;
320 
321 	/*
322 	 * Set the block level to ensure there is space to generate a
323 	 * large number of descriptors for TSO.
324 	 */
325 	block_level = EFX_TXQ_LIMIT(txq->entries) - txq->max_pkt_desc;
326 
327 	/* Have we reached the block level? */
328 	if (level < block_level)
329 		return;
330 
331 	/* Reap, and check again */
332 	sfxge_tx_qreap(txq);
333 	level = txq->added - txq->reaped;
334 	if (level < block_level)
335 		return;
336 
337 	txq->blocked = 1;
338 
339 	/*
340 	 * Avoid a race with completion interrupt handling that could leave
341 	 * the queue blocked.
342 	 */
343 	mb();
344 	sfxge_tx_qreap(txq);
345 	level = txq->added - txq->reaped;
346 	if (level < block_level) {
347 		mb();
348 		txq->blocked = 0;
349 	}
350 }
351 
352 static int sfxge_tx_queue_mbuf(struct sfxge_txq *txq, struct mbuf *mbuf)
353 {
354 	bus_dmamap_t *used_map;
355 	bus_dmamap_t map;
356 	bus_dma_segment_t dma_seg[SFXGE_TX_MAPPING_MAX_SEG];
357 	unsigned int id;
358 	struct sfxge_tx_mapping *stmp;
359 	efx_desc_t *desc;
360 	int n_dma_seg;
361 	int rc;
362 	int i;
363 	int eop;
364 	int vlan_tagged;
365 
366 	KASSERT(!txq->blocked, ("txq->blocked"));
367 
368 #if SFXGE_TX_PARSE_EARLY
369 	/*
370 	 * If software TSO is used, we still need to copy packet header,
371 	 * even if we have already parsed it early before enqueue.
372 	 */
373 	if ((mbuf->m_pkthdr.csum_flags & CSUM_TSO) &&
374 	    (txq->tso_fw_assisted == 0))
375 		prefetch_read_many(mbuf->m_data);
376 #else
377 	/*
378 	 * Prefetch packet header since we need to parse it and extract
379 	 * IP ID, TCP sequence number and flags.
380 	 */
381 	if (mbuf->m_pkthdr.csum_flags & CSUM_TSO)
382 		prefetch_read_many(mbuf->m_data);
383 #endif
384 
385 	if (__predict_false(txq->init_state != SFXGE_TXQ_STARTED)) {
386 		rc = EINTR;
387 		goto reject;
388 	}
389 
390 	/* Load the packet for DMA. */
391 	id = txq->added & txq->ptr_mask;
392 	stmp = &txq->stmp[id];
393 	rc = bus_dmamap_load_mbuf_sg(txq->packet_dma_tag, stmp->map,
394 				     mbuf, dma_seg, &n_dma_seg, 0);
395 	if (rc == EFBIG) {
396 		/* Try again. */
397 		struct mbuf *new_mbuf = m_collapse(mbuf, M_NOWAIT,
398 						   SFXGE_TX_MAPPING_MAX_SEG);
399 		if (new_mbuf == NULL)
400 			goto reject;
401 		++txq->collapses;
402 		mbuf = new_mbuf;
403 		rc = bus_dmamap_load_mbuf_sg(txq->packet_dma_tag,
404 					     stmp->map, mbuf,
405 					     dma_seg, &n_dma_seg, 0);
406 	}
407 	if (rc != 0)
408 		goto reject;
409 
410 	/* Make the packet visible to the hardware. */
411 	bus_dmamap_sync(txq->packet_dma_tag, stmp->map, BUS_DMASYNC_PREWRITE);
412 
413 	used_map = &stmp->map;
414 
415 	vlan_tagged = sfxge_tx_maybe_insert_tag(txq, mbuf);
416 	if (vlan_tagged) {
417 		sfxge_next_stmp(txq, &stmp);
418 	}
419 	if (mbuf->m_pkthdr.csum_flags & CSUM_TSO) {
420 		rc = sfxge_tx_queue_tso(txq, mbuf, dma_seg, n_dma_seg, vlan_tagged);
421 		if (rc < 0)
422 			goto reject_mapped;
423 		stmp = &txq->stmp[(rc - 1) & txq->ptr_mask];
424 	} else {
425 		/* Add the mapping to the fragment list, and set flags
426 		 * for the buffer.
427 		 */
428 
429 		i = 0;
430 		for (;;) {
431 			desc = &txq->pend_desc[i + vlan_tagged];
432 			eop = (i == n_dma_seg - 1);
433 			efx_tx_qdesc_dma_create(txq->common,
434 						dma_seg[i].ds_addr,
435 						dma_seg[i].ds_len,
436 						eop,
437 						desc);
438 			if (eop)
439 				break;
440 			i++;
441 			sfxge_next_stmp(txq, &stmp);
442 		}
443 		txq->n_pend_desc = n_dma_seg + vlan_tagged;
444 	}
445 
446 	/*
447 	 * If the mapping required more than one descriptor
448 	 * then we need to associate the DMA map with the last
449 	 * descriptor, not the first.
450 	 */
451 	if (used_map != &stmp->map) {
452 		map = stmp->map;
453 		stmp->map = *used_map;
454 		*used_map = map;
455 	}
456 
457 	stmp->u.mbuf = mbuf;
458 	stmp->flags = TX_BUF_UNMAP | TX_BUF_MBUF;
459 
460 	/* Post the fragment list. */
461 	sfxge_tx_qlist_post(txq);
462 
463 	return (0);
464 
465 reject_mapped:
466 	bus_dmamap_unload(txq->packet_dma_tag, *used_map);
467 reject:
468 	/* Drop the packet on the floor. */
469 	m_freem(mbuf);
470 	++txq->drops;
471 
472 	return (rc);
473 }
474 
475 /*
476  * Drain the deferred packet list into the transmit queue.
477  */
478 static void
479 sfxge_tx_qdpl_drain(struct sfxge_txq *txq)
480 {
481 	struct sfxge_softc *sc;
482 	struct sfxge_tx_dpl *stdp;
483 	struct mbuf *mbuf, *next;
484 	unsigned int count;
485 	unsigned int non_tcp_count;
486 	unsigned int pushed;
487 	int rc;
488 
489 	SFXGE_TXQ_LOCK_ASSERT_OWNED(txq);
490 
491 	sc = txq->sc;
492 	stdp = &txq->dpl;
493 	pushed = txq->added;
494 
495 	if (__predict_true(txq->init_state == SFXGE_TXQ_STARTED)) {
496 		prefetch_read_many(sc->enp);
497 		prefetch_read_many(txq->common);
498 	}
499 
500 	mbuf = stdp->std_get;
501 	count = stdp->std_get_count;
502 	non_tcp_count = stdp->std_get_non_tcp_count;
503 
504 	if (count > stdp->std_get_hiwat)
505 		stdp->std_get_hiwat = count;
506 
507 	while (count != 0) {
508 		KASSERT(mbuf != NULL, ("mbuf == NULL"));
509 
510 		next = mbuf->m_nextpkt;
511 		mbuf->m_nextpkt = NULL;
512 
513 		ETHER_BPF_MTAP(sc->ifnet, mbuf); /* packet capture */
514 
515 		if (next != NULL)
516 			prefetch_read_many(next);
517 
518 		rc = sfxge_tx_queue_mbuf(txq, mbuf);
519 		--count;
520 		non_tcp_count -= sfxge_is_mbuf_non_tcp(mbuf);
521 		mbuf = next;
522 		if (rc != 0)
523 			continue;
524 
525 		if (txq->blocked)
526 			break;
527 
528 		/* Push the fragments to the hardware in batches. */
529 		if (txq->added - pushed >= SFXGE_TX_BATCH) {
530 			efx_tx_qpush(txq->common, txq->added, pushed);
531 			pushed = txq->added;
532 		}
533 	}
534 
535 	if (count == 0) {
536 		KASSERT(mbuf == NULL, ("mbuf != NULL"));
537 		KASSERT(non_tcp_count == 0,
538 			("inconsistent TCP/non-TCP detection"));
539 		stdp->std_get = NULL;
540 		stdp->std_get_count = 0;
541 		stdp->std_get_non_tcp_count = 0;
542 		stdp->std_getp = &stdp->std_get;
543 	} else {
544 		stdp->std_get = mbuf;
545 		stdp->std_get_count = count;
546 		stdp->std_get_non_tcp_count = non_tcp_count;
547 	}
548 
549 	if (txq->added != pushed)
550 		efx_tx_qpush(txq->common, txq->added, pushed);
551 
552 	KASSERT(txq->blocked || stdp->std_get_count == 0,
553 		("queue unblocked but count is non-zero"));
554 }
555 
556 #define	SFXGE_TX_QDPL_PENDING(_txq)	((_txq)->dpl.std_put != 0)
557 
558 /*
559  * Service the deferred packet list.
560  *
561  * NOTE: drops the txq mutex!
562  */
563 static void
564 sfxge_tx_qdpl_service(struct sfxge_txq *txq)
565 {
566 	SFXGE_TXQ_LOCK_ASSERT_OWNED(txq);
567 
568 	do {
569 		if (SFXGE_TX_QDPL_PENDING(txq))
570 			sfxge_tx_qdpl_swizzle(txq);
571 
572 		if (!txq->blocked)
573 			sfxge_tx_qdpl_drain(txq);
574 
575 		SFXGE_TXQ_UNLOCK(txq);
576 	} while (SFXGE_TX_QDPL_PENDING(txq) &&
577 		 SFXGE_TXQ_TRYLOCK(txq));
578 }
579 
580 /*
581  * Put a packet on the deferred packet get-list.
582  */
583 static int
584 sfxge_tx_qdpl_put_locked(struct sfxge_txq *txq, struct mbuf *mbuf)
585 {
586 	struct sfxge_tx_dpl *stdp;
587 
588 	stdp = &txq->dpl;
589 
590 	KASSERT(mbuf->m_nextpkt == NULL, ("mbuf->m_nextpkt != NULL"));
591 
592 	SFXGE_TXQ_LOCK_ASSERT_OWNED(txq);
593 
594 	if (stdp->std_get_count >= stdp->std_get_max) {
595 		txq->get_overflow++;
596 		return (ENOBUFS);
597 	}
598 	if (sfxge_is_mbuf_non_tcp(mbuf)) {
599 		if (stdp->std_get_non_tcp_count >=
600 		    stdp->std_get_non_tcp_max) {
601 			txq->get_non_tcp_overflow++;
602 			return (ENOBUFS);
603 		}
604 		stdp->std_get_non_tcp_count++;
605 	}
606 
607 	*(stdp->std_getp) = mbuf;
608 	stdp->std_getp = &mbuf->m_nextpkt;
609 	stdp->std_get_count++;
610 
611 	return (0);
612 }
613 
614 /*
615  * Put a packet on the deferred packet put-list.
616  *
617  * We overload the csum_data field in the mbuf to keep track of this length
618  * because there is no cheap alternative to avoid races.
619  */
620 static int
621 sfxge_tx_qdpl_put_unlocked(struct sfxge_txq *txq, struct mbuf *mbuf)
622 {
623 	struct sfxge_tx_dpl *stdp;
624 	volatile uintptr_t *putp;
625 	uintptr_t old;
626 	uintptr_t new;
627 	unsigned int put_count;
628 
629 	KASSERT(mbuf->m_nextpkt == NULL, ("mbuf->m_nextpkt != NULL"));
630 
631 	SFXGE_TXQ_LOCK_ASSERT_NOTOWNED(txq);
632 
633 	stdp = &txq->dpl;
634 	putp = &stdp->std_put;
635 	new = (uintptr_t)mbuf;
636 
637 	do {
638 		old = *putp;
639 		if (old != 0) {
640 			struct mbuf *mp = (struct mbuf *)old;
641 			put_count = mp->m_pkthdr.csum_data;
642 		} else
643 			put_count = 0;
644 		if (put_count >= stdp->std_put_max) {
645 			atomic_add_long(&txq->put_overflow, 1);
646 			return (ENOBUFS);
647 		}
648 		mbuf->m_pkthdr.csum_data = put_count + 1;
649 		mbuf->m_nextpkt = (void *)old;
650 	} while (atomic_cmpset_ptr(putp, old, new) == 0);
651 
652 	return (0);
653 }
654 
655 /*
656  * Called from if_transmit - will try to grab the txq lock and enqueue to the
657  * put list if it succeeds, otherwise try to push onto the defer list if space.
658  */
659 static int
660 sfxge_tx_packet_add(struct sfxge_txq *txq, struct mbuf *m)
661 {
662 	int rc;
663 
664 	if (!SFXGE_LINK_UP(txq->sc)) {
665 		atomic_add_long(&txq->netdown_drops, 1);
666 		return (ENETDOWN);
667 	}
668 
669 	/*
670 	 * Try to grab the txq lock.  If we are able to get the lock,
671 	 * the packet will be appended to the "get list" of the deferred
672 	 * packet list.  Otherwise, it will be pushed on the "put list".
673 	 */
674 	if (SFXGE_TXQ_TRYLOCK(txq)) {
675 		/* First swizzle put-list to get-list to keep order */
676 		sfxge_tx_qdpl_swizzle(txq);
677 
678 		rc = sfxge_tx_qdpl_put_locked(txq, m);
679 
680 		/* Try to service the list. */
681 		sfxge_tx_qdpl_service(txq);
682 		/* Lock has been dropped. */
683 	} else {
684 		rc = sfxge_tx_qdpl_put_unlocked(txq, m);
685 
686 		/*
687 		 * Try to grab the lock again.
688 		 *
689 		 * If we are able to get the lock, we need to process
690 		 * the deferred packet list.  If we are not able to get
691 		 * the lock, another thread is processing the list.
692 		 */
693 		if ((rc == 0) && SFXGE_TXQ_TRYLOCK(txq)) {
694 			sfxge_tx_qdpl_service(txq);
695 			/* Lock has been dropped. */
696 		}
697 	}
698 
699 	SFXGE_TXQ_LOCK_ASSERT_NOTOWNED(txq);
700 
701 	return (rc);
702 }
703 
704 static void
705 sfxge_tx_qdpl_flush(struct sfxge_txq *txq)
706 {
707 	struct sfxge_tx_dpl *stdp = &txq->dpl;
708 	struct mbuf *mbuf, *next;
709 
710 	SFXGE_TXQ_LOCK(txq);
711 
712 	sfxge_tx_qdpl_swizzle(txq);
713 	for (mbuf = stdp->std_get; mbuf != NULL; mbuf = next) {
714 		next = mbuf->m_nextpkt;
715 		m_freem(mbuf);
716 	}
717 	stdp->std_get = NULL;
718 	stdp->std_get_count = 0;
719 	stdp->std_get_non_tcp_count = 0;
720 	stdp->std_getp = &stdp->std_get;
721 
722 	SFXGE_TXQ_UNLOCK(txq);
723 }
724 
725 void
726 sfxge_if_qflush(struct ifnet *ifp)
727 {
728 	struct sfxge_softc *sc;
729 	unsigned int i;
730 
731 	sc = ifp->if_softc;
732 
733 	for (i = 0; i < sc->txq_count; i++)
734 		sfxge_tx_qdpl_flush(sc->txq[i]);
735 }
736 
737 #if SFXGE_TX_PARSE_EARLY
738 
739 /* There is little space for user data in mbuf pkthdr, so we
740  * use l*hlen fields which are not used by the driver otherwise
741  * to store header offsets.
742  * The fields are 8-bit, but it's ok, no header may be longer than 255 bytes.
743  */
744 
745 
746 #define TSO_MBUF_PROTO(_mbuf)    ((_mbuf)->m_pkthdr.PH_loc.sixteen[0])
747 /* We abuse l5hlen here because PH_loc can hold only 64 bits of data */
748 #define TSO_MBUF_FLAGS(_mbuf)    ((_mbuf)->m_pkthdr.l5hlen)
749 #define TSO_MBUF_PACKETID(_mbuf) ((_mbuf)->m_pkthdr.PH_loc.sixteen[1])
750 #define TSO_MBUF_SEQNUM(_mbuf)   ((_mbuf)->m_pkthdr.PH_loc.thirtytwo[1])
751 
752 static void sfxge_parse_tx_packet(struct mbuf *mbuf)
753 {
754 	struct ether_header *eh = mtod(mbuf, struct ether_header *);
755 	const struct tcphdr *th;
756 	struct tcphdr th_copy;
757 
758 	/* Find network protocol and header */
759 	TSO_MBUF_PROTO(mbuf) = eh->ether_type;
760 	if (TSO_MBUF_PROTO(mbuf) == htons(ETHERTYPE_VLAN)) {
761 		struct ether_vlan_header *veh =
762 			mtod(mbuf, struct ether_vlan_header *);
763 		TSO_MBUF_PROTO(mbuf) = veh->evl_proto;
764 		mbuf->m_pkthdr.l2hlen = sizeof(*veh);
765 	} else {
766 		mbuf->m_pkthdr.l2hlen = sizeof(*eh);
767 	}
768 
769 	/* Find TCP header */
770 	if (TSO_MBUF_PROTO(mbuf) == htons(ETHERTYPE_IP)) {
771 		const struct ip *iph = (const struct ip *)mtodo(mbuf, mbuf->m_pkthdr.l2hlen);
772 
773 		KASSERT(iph->ip_p == IPPROTO_TCP,
774 			("TSO required on non-TCP packet"));
775 		mbuf->m_pkthdr.l3hlen = mbuf->m_pkthdr.l2hlen + 4 * iph->ip_hl;
776 		TSO_MBUF_PACKETID(mbuf) = iph->ip_id;
777 	} else {
778 		KASSERT(TSO_MBUF_PROTO(mbuf) == htons(ETHERTYPE_IPV6),
779 			("TSO required on non-IP packet"));
780 		KASSERT(((const struct ip6_hdr *)mtodo(mbuf, mbuf->m_pkthdr.l2hlen))->ip6_nxt ==
781 			IPPROTO_TCP,
782 			("TSO required on non-TCP packet"));
783 		mbuf->m_pkthdr.l3hlen = mbuf->m_pkthdr.l2hlen + sizeof(struct ip6_hdr);
784 		TSO_MBUF_PACKETID(mbuf) = 0;
785 	}
786 
787 	KASSERT(mbuf->m_len >= mbuf->m_pkthdr.l3hlen,
788 		("network header is fragmented in mbuf"));
789 
790 	/* We need TCP header including flags (window is the next) */
791 	if (mbuf->m_len < mbuf->m_pkthdr.l3hlen + offsetof(struct tcphdr, th_win)) {
792 		m_copydata(mbuf, mbuf->m_pkthdr.l3hlen, sizeof(th_copy),
793 			   (caddr_t)&th_copy);
794 		th = &th_copy;
795 	} else {
796 		th = (const struct tcphdr *)mtodo(mbuf, mbuf->m_pkthdr.l3hlen);
797 	}
798 
799 	mbuf->m_pkthdr.l4hlen = mbuf->m_pkthdr.l3hlen + 4 * th->th_off;
800 	TSO_MBUF_SEQNUM(mbuf) = ntohl(th->th_seq);
801 
802 	/* These flags must not be duplicated */
803 	/*
804 	 * RST should not be duplicated as well, but FreeBSD kernel
805 	 * generates TSO packets with RST flag. So, do not assert
806 	 * its absence.
807 	 */
808 	KASSERT(!(th->th_flags & (TH_URG | TH_SYN)),
809 		("incompatible TCP flag 0x%x on TSO packet",
810 		 th->th_flags & (TH_URG | TH_SYN)));
811 	TSO_MBUF_FLAGS(mbuf) = th->th_flags;
812 }
813 #endif
814 
815 /*
816  * TX start -- called by the stack.
817  */
818 int
819 sfxge_if_transmit(struct ifnet *ifp, struct mbuf *m)
820 {
821 	struct sfxge_softc *sc;
822 	struct sfxge_txq *txq;
823 	int rc;
824 
825 	sc = (struct sfxge_softc *)ifp->if_softc;
826 
827 	/*
828 	 * Transmit may be called when interface is up from the kernel
829 	 * point of view, but not yet up (in progress) from the driver
830 	 * point of view. I.e. link aggregation bring up.
831 	 * Transmit may be called when interface is up from the driver
832 	 * point of view, but already down from the kernel point of
833 	 * view. I.e. Rx when interface shutdown is in progress.
834 	 */
835 	KASSERT((ifp->if_flags & IFF_UP) || (sc->if_flags & IFF_UP),
836 		("interface not up"));
837 
838 	/* Pick the desired transmit queue. */
839 	if (m->m_pkthdr.csum_flags &
840 	    (CSUM_DELAY_DATA | CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_TSO)) {
841 		int index = 0;
842 
843 #ifdef RSS
844 		uint32_t bucket_id;
845 
846 		/*
847 		 * Select a TX queue which matches the corresponding
848 		 * RX queue for the hash in order to assign both
849 		 * TX and RX parts of the flow to the same CPU
850 		 */
851 		if (rss_m2bucket(m, &bucket_id) == 0)
852 			index = bucket_id % (sc->txq_count - (SFXGE_TXQ_NTYPES - 1));
853 #else
854 		/* check if flowid is set */
855 		if (M_HASHTYPE_GET(m) != M_HASHTYPE_NONE) {
856 			uint32_t hash = m->m_pkthdr.flowid;
857 			uint32_t idx = hash % nitems(sc->rx_indir_table);
858 
859 			index = sc->rx_indir_table[idx];
860 		}
861 #endif
862 #if SFXGE_TX_PARSE_EARLY
863 		if (m->m_pkthdr.csum_flags & CSUM_TSO)
864 			sfxge_parse_tx_packet(m);
865 #endif
866 		txq = sc->txq[SFXGE_TXQ_IP_TCP_UDP_CKSUM + index];
867 	} else if (m->m_pkthdr.csum_flags & CSUM_DELAY_IP) {
868 		txq = sc->txq[SFXGE_TXQ_IP_CKSUM];
869 	} else {
870 		txq = sc->txq[SFXGE_TXQ_NON_CKSUM];
871 	}
872 
873 	rc = sfxge_tx_packet_add(txq, m);
874 	if (rc != 0)
875 		m_freem(m);
876 
877 	return (rc);
878 }
879 
880 /*
881  * Software "TSO".  Not quite as good as doing it in hardware, but
882  * still faster than segmenting in the stack.
883  */
884 
885 struct sfxge_tso_state {
886 	/* Output position */
887 	unsigned out_len;	/* Remaining length in current segment */
888 	unsigned seqnum;	/* Current sequence number */
889 	unsigned packet_space;	/* Remaining space in current packet */
890 	unsigned segs_space;	/* Remaining number of DMA segments
891 				   for the packet (FATSOv2 only) */
892 
893 	/* Input position */
894 	uint64_t dma_addr;	/* DMA address of current position */
895 	unsigned in_len;	/* Remaining length in current mbuf */
896 
897 	const struct mbuf *mbuf; /* Input mbuf (head of chain) */
898 	u_short protocol;	/* Network protocol (after VLAN decap) */
899 	ssize_t nh_off;		/* Offset of network header */
900 	ssize_t tcph_off;	/* Offset of TCP header */
901 	unsigned header_len;	/* Number of bytes of header */
902 	unsigned seg_size;	/* TCP segment size */
903 	int fw_assisted;	/* Use FW-assisted TSO */
904 	u_short packet_id;	/* IPv4 packet ID from the original packet */
905 	uint8_t tcp_flags;	/* TCP flags */
906 	efx_desc_t header_desc; /* Precomputed header descriptor for
907 				 * FW-assisted TSO */
908 };
909 
910 #if !SFXGE_TX_PARSE_EARLY
911 static const struct ip *tso_iph(const struct sfxge_tso_state *tso)
912 {
913 	KASSERT(tso->protocol == htons(ETHERTYPE_IP),
914 		("tso_iph() in non-IPv4 state"));
915 	return (const struct ip *)(tso->mbuf->m_data + tso->nh_off);
916 }
917 
918 static __unused const struct ip6_hdr *tso_ip6h(const struct sfxge_tso_state *tso)
919 {
920 	KASSERT(tso->protocol == htons(ETHERTYPE_IPV6),
921 		("tso_ip6h() in non-IPv6 state"));
922 	return (const struct ip6_hdr *)(tso->mbuf->m_data + tso->nh_off);
923 }
924 
925 static const struct tcphdr *tso_tcph(const struct sfxge_tso_state *tso)
926 {
927 	return (const struct tcphdr *)(tso->mbuf->m_data + tso->tcph_off);
928 }
929 #endif
930 
931 
932 /* Size of preallocated TSO header buffers.  Larger blocks must be
933  * allocated from the heap.
934  */
935 #define	TSOH_STD_SIZE	128
936 
937 /* At most half the descriptors in the queue at any time will refer to
938  * a TSO header buffer, since they must always be followed by a
939  * payload descriptor referring to an mbuf.
940  */
941 #define	TSOH_COUNT(_txq_entries)	((_txq_entries) / 2u)
942 #define	TSOH_PER_PAGE	(PAGE_SIZE / TSOH_STD_SIZE)
943 #define	TSOH_PAGE_COUNT(_txq_entries)	\
944 	howmany(TSOH_COUNT(_txq_entries), TSOH_PER_PAGE)
945 
946 static int tso_init(struct sfxge_txq *txq)
947 {
948 	struct sfxge_softc *sc = txq->sc;
949 	unsigned int tsoh_page_count = TSOH_PAGE_COUNT(sc->txq_entries);
950 	int i, rc;
951 
952 	/* Allocate TSO header buffers */
953 	txq->tsoh_buffer = malloc(tsoh_page_count * sizeof(txq->tsoh_buffer[0]),
954 				  M_SFXGE, M_WAITOK);
955 
956 	for (i = 0; i < tsoh_page_count; i++) {
957 		rc = sfxge_dma_alloc(sc, PAGE_SIZE, &txq->tsoh_buffer[i]);
958 		if (rc != 0)
959 			goto fail;
960 	}
961 
962 	return (0);
963 
964 fail:
965 	while (i-- > 0)
966 		sfxge_dma_free(&txq->tsoh_buffer[i]);
967 	free(txq->tsoh_buffer, M_SFXGE);
968 	txq->tsoh_buffer = NULL;
969 	return (rc);
970 }
971 
972 static void tso_fini(struct sfxge_txq *txq)
973 {
974 	int i;
975 
976 	if (txq->tsoh_buffer != NULL) {
977 		for (i = 0; i < TSOH_PAGE_COUNT(txq->sc->txq_entries); i++)
978 			sfxge_dma_free(&txq->tsoh_buffer[i]);
979 		free(txq->tsoh_buffer, M_SFXGE);
980 	}
981 }
982 
983 static void tso_start(struct sfxge_txq *txq, struct sfxge_tso_state *tso,
984 		      const bus_dma_segment_t *hdr_dma_seg,
985 		      struct mbuf *mbuf)
986 {
987 	const efx_nic_cfg_t *encp = efx_nic_cfg_get(txq->sc->enp);
988 #if !SFXGE_TX_PARSE_EARLY
989 	struct ether_header *eh = mtod(mbuf, struct ether_header *);
990 	const struct tcphdr *th;
991 	struct tcphdr th_copy;
992 #endif
993 
994 	tso->fw_assisted = txq->tso_fw_assisted;
995 	tso->mbuf = mbuf;
996 
997 	/* Find network protocol and header */
998 #if !SFXGE_TX_PARSE_EARLY
999 	tso->protocol = eh->ether_type;
1000 	if (tso->protocol == htons(ETHERTYPE_VLAN)) {
1001 		struct ether_vlan_header *veh =
1002 			mtod(mbuf, struct ether_vlan_header *);
1003 		tso->protocol = veh->evl_proto;
1004 		tso->nh_off = sizeof(*veh);
1005 	} else {
1006 		tso->nh_off = sizeof(*eh);
1007 	}
1008 #else
1009 	tso->protocol = TSO_MBUF_PROTO(mbuf);
1010 	tso->nh_off = mbuf->m_pkthdr.l2hlen;
1011 	tso->tcph_off = mbuf->m_pkthdr.l3hlen;
1012 	tso->packet_id = ntohs(TSO_MBUF_PACKETID(mbuf));
1013 #endif
1014 
1015 #if !SFXGE_TX_PARSE_EARLY
1016 	/* Find TCP header */
1017 	if (tso->protocol == htons(ETHERTYPE_IP)) {
1018 		KASSERT(tso_iph(tso)->ip_p == IPPROTO_TCP,
1019 			("TSO required on non-TCP packet"));
1020 		tso->tcph_off = tso->nh_off + 4 * tso_iph(tso)->ip_hl;
1021 		tso->packet_id = ntohs(tso_iph(tso)->ip_id);
1022 	} else {
1023 		KASSERT(tso->protocol == htons(ETHERTYPE_IPV6),
1024 			("TSO required on non-IP packet"));
1025 		KASSERT(tso_ip6h(tso)->ip6_nxt == IPPROTO_TCP,
1026 			("TSO required on non-TCP packet"));
1027 		tso->tcph_off = tso->nh_off + sizeof(struct ip6_hdr);
1028 		tso->packet_id = 0;
1029 	}
1030 #endif
1031 
1032 
1033 	if (tso->fw_assisted &&
1034 	    __predict_false(tso->tcph_off >
1035 			    encp->enc_tx_tso_tcp_header_offset_limit)) {
1036 		tso->fw_assisted = 0;
1037 	}
1038 
1039 
1040 #if !SFXGE_TX_PARSE_EARLY
1041 	KASSERT(mbuf->m_len >= tso->tcph_off,
1042 		("network header is fragmented in mbuf"));
1043 	/* We need TCP header including flags (window is the next) */
1044 	if (mbuf->m_len < tso->tcph_off + offsetof(struct tcphdr, th_win)) {
1045 		m_copydata(tso->mbuf, tso->tcph_off, sizeof(th_copy),
1046 			   (caddr_t)&th_copy);
1047 		th = &th_copy;
1048 	} else {
1049 		th = tso_tcph(tso);
1050 	}
1051 	tso->header_len = tso->tcph_off + 4 * th->th_off;
1052 #else
1053 	tso->header_len = mbuf->m_pkthdr.l4hlen;
1054 #endif
1055 	tso->seg_size = mbuf->m_pkthdr.tso_segsz;
1056 
1057 #if !SFXGE_TX_PARSE_EARLY
1058 	tso->seqnum = ntohl(th->th_seq);
1059 
1060 	/* These flags must not be duplicated */
1061 	/*
1062 	 * RST should not be duplicated as well, but FreeBSD kernel
1063 	 * generates TSO packets with RST flag. So, do not assert
1064 	 * its absence.
1065 	 */
1066 	KASSERT(!(th->th_flags & (TH_URG | TH_SYN)),
1067 		("incompatible TCP flag 0x%x on TSO packet",
1068 		 th->th_flags & (TH_URG | TH_SYN)));
1069 	tso->tcp_flags = th->th_flags;
1070 #else
1071 	tso->seqnum = TSO_MBUF_SEQNUM(mbuf);
1072 	tso->tcp_flags = TSO_MBUF_FLAGS(mbuf);
1073 #endif
1074 
1075 	tso->out_len = mbuf->m_pkthdr.len - tso->header_len;
1076 
1077 	if (tso->fw_assisted) {
1078 		if (hdr_dma_seg->ds_len >= tso->header_len)
1079 			efx_tx_qdesc_dma_create(txq->common,
1080 						hdr_dma_seg->ds_addr,
1081 						tso->header_len,
1082 						B_FALSE,
1083 						&tso->header_desc);
1084 		else
1085 			tso->fw_assisted = 0;
1086 	}
1087 }
1088 
1089 /*
1090  * tso_fill_packet_with_fragment - form descriptors for the current fragment
1091  *
1092  * Form descriptors for the current fragment, until we reach the end
1093  * of fragment or end-of-packet.  Return 0 on success, 1 if not enough
1094  * space.
1095  */
1096 static void tso_fill_packet_with_fragment(struct sfxge_txq *txq,
1097 					  struct sfxge_tso_state *tso)
1098 {
1099 	efx_desc_t *desc;
1100 	int n;
1101 	uint64_t dma_addr = tso->dma_addr;
1102 	boolean_t eop;
1103 
1104 	if (tso->in_len == 0 || tso->packet_space == 0)
1105 		return;
1106 
1107 	KASSERT(tso->in_len > 0, ("TSO input length went negative"));
1108 	KASSERT(tso->packet_space > 0, ("TSO packet space went negative"));
1109 
1110 	if (tso->fw_assisted & SFXGE_FATSOV2) {
1111 		n = tso->in_len;
1112 		tso->out_len -= n;
1113 		tso->seqnum += n;
1114 		tso->in_len = 0;
1115 		if (n < tso->packet_space) {
1116 			tso->packet_space -= n;
1117 			tso->segs_space--;
1118 		} else {
1119 			tso->packet_space = tso->seg_size -
1120 			    (n - tso->packet_space) % tso->seg_size;
1121 			tso->segs_space =
1122 			    EFX_TX_FATSOV2_DMA_SEGS_PER_PKT_MAX - 1 -
1123 			    (tso->packet_space != tso->seg_size);
1124 		}
1125 	} else {
1126 		n = min(tso->in_len, tso->packet_space);
1127 		tso->packet_space -= n;
1128 		tso->out_len -= n;
1129 		tso->dma_addr += n;
1130 		tso->in_len -= n;
1131 	}
1132 
1133 	/*
1134 	 * It is OK to use binary OR below to avoid extra branching
1135 	 * since all conditions may always be checked.
1136 	 */
1137 	eop = (tso->out_len == 0) | (tso->packet_space == 0) |
1138 	    (tso->segs_space == 0);
1139 
1140 	desc = &txq->pend_desc[txq->n_pend_desc++];
1141 	efx_tx_qdesc_dma_create(txq->common, dma_addr, n, eop, desc);
1142 }
1143 
1144 /* Callback from bus_dmamap_load() for long TSO headers. */
1145 static void tso_map_long_header(void *dma_addr_ret,
1146 				bus_dma_segment_t *segs, int nseg,
1147 				int error)
1148 {
1149 	*(uint64_t *)dma_addr_ret = ((__predict_true(error == 0) &&
1150 				      __predict_true(nseg == 1)) ?
1151 				     segs->ds_addr : 0);
1152 }
1153 
1154 /*
1155  * tso_start_new_packet - generate a new header and prepare for the new packet
1156  *
1157  * Generate a new header and prepare for the new packet.  Return 0 on
1158  * success, or an error code if failed to alloc header.
1159  */
1160 static int tso_start_new_packet(struct sfxge_txq *txq,
1161 				struct sfxge_tso_state *tso,
1162 				unsigned int *idp)
1163 {
1164 	unsigned int id = *idp;
1165 	struct tcphdr *tsoh_th;
1166 	unsigned ip_length;
1167 	caddr_t header;
1168 	uint64_t dma_addr;
1169 	bus_dmamap_t map;
1170 	efx_desc_t *desc;
1171 	int rc;
1172 
1173 	if (tso->fw_assisted) {
1174 		if (tso->fw_assisted & SFXGE_FATSOV2) {
1175 			/* Add 2 FATSOv2 option descriptors */
1176 			desc = &txq->pend_desc[txq->n_pend_desc];
1177 			efx_tx_qdesc_tso2_create(txq->common,
1178 						 tso->packet_id,
1179 						 tso->seqnum,
1180 						 tso->seg_size,
1181 						 desc,
1182 						 EFX_TX_FATSOV2_OPT_NDESCS);
1183 			desc += EFX_TX_FATSOV2_OPT_NDESCS;
1184 			txq->n_pend_desc += EFX_TX_FATSOV2_OPT_NDESCS;
1185 			KASSERT(txq->stmp[id].flags == 0, ("stmp flags are not 0"));
1186 			id = (id + EFX_TX_FATSOV2_OPT_NDESCS) & txq->ptr_mask;
1187 
1188 			tso->segs_space =
1189 			    EFX_TX_FATSOV2_DMA_SEGS_PER_PKT_MAX - 1;
1190 		} else {
1191 			uint8_t tcp_flags = tso->tcp_flags;
1192 
1193 			if (tso->out_len > tso->seg_size)
1194 				tcp_flags &= ~(TH_FIN | TH_PUSH);
1195 
1196 			/* Add FATSOv1 option descriptor */
1197 			desc = &txq->pend_desc[txq->n_pend_desc++];
1198 			efx_tx_qdesc_tso_create(txq->common,
1199 						tso->packet_id,
1200 						tso->seqnum,
1201 						tcp_flags,
1202 						desc++);
1203 			KASSERT(txq->stmp[id].flags == 0, ("stmp flags are not 0"));
1204 			id = (id + 1) & txq->ptr_mask;
1205 
1206 			tso->seqnum += tso->seg_size;
1207 			tso->segs_space = UINT_MAX;
1208 		}
1209 
1210 		/* Header DMA descriptor */
1211 		*desc = tso->header_desc;
1212 		txq->n_pend_desc++;
1213 		KASSERT(txq->stmp[id].flags == 0, ("stmp flags are not 0"));
1214 		id = (id + 1) & txq->ptr_mask;
1215 	} else {
1216 		/* Allocate a DMA-mapped header buffer. */
1217 		if (__predict_true(tso->header_len <= TSOH_STD_SIZE)) {
1218 			unsigned int page_index = (id / 2) / TSOH_PER_PAGE;
1219 			unsigned int buf_index = (id / 2) % TSOH_PER_PAGE;
1220 
1221 			header = (txq->tsoh_buffer[page_index].esm_base +
1222 				  buf_index * TSOH_STD_SIZE);
1223 			dma_addr = (txq->tsoh_buffer[page_index].esm_addr +
1224 				    buf_index * TSOH_STD_SIZE);
1225 			map = txq->tsoh_buffer[page_index].esm_map;
1226 
1227 			KASSERT(txq->stmp[id].flags == 0,
1228 				("stmp flags are not 0"));
1229 		} else {
1230 			struct sfxge_tx_mapping *stmp = &txq->stmp[id];
1231 
1232 			/* We cannot use bus_dmamem_alloc() as that may sleep */
1233 			header = malloc(tso->header_len, M_SFXGE, M_NOWAIT);
1234 			if (__predict_false(!header))
1235 				return (ENOMEM);
1236 			rc = bus_dmamap_load(txq->packet_dma_tag, stmp->map,
1237 					     header, tso->header_len,
1238 					     tso_map_long_header, &dma_addr,
1239 					     BUS_DMA_NOWAIT);
1240 			if (__predict_false(dma_addr == 0)) {
1241 				if (rc == 0) {
1242 					/* Succeeded but got >1 segment */
1243 					bus_dmamap_unload(txq->packet_dma_tag,
1244 							  stmp->map);
1245 					rc = EINVAL;
1246 				}
1247 				free(header, M_SFXGE);
1248 				return (rc);
1249 			}
1250 			map = stmp->map;
1251 
1252 			txq->tso_long_headers++;
1253 			stmp->u.heap_buf = header;
1254 			stmp->flags = TX_BUF_UNMAP;
1255 		}
1256 
1257 		tsoh_th = (struct tcphdr *)(header + tso->tcph_off);
1258 
1259 		/* Copy and update the headers. */
1260 		m_copydata(tso->mbuf, 0, tso->header_len, header);
1261 
1262 		tsoh_th->th_seq = htonl(tso->seqnum);
1263 		tso->seqnum += tso->seg_size;
1264 		if (tso->out_len > tso->seg_size) {
1265 			/* This packet will not finish the TSO burst. */
1266 			ip_length = tso->header_len - tso->nh_off + tso->seg_size;
1267 			tsoh_th->th_flags &= ~(TH_FIN | TH_PUSH);
1268 		} else {
1269 			/* This packet will be the last in the TSO burst. */
1270 			ip_length = tso->header_len - tso->nh_off + tso->out_len;
1271 		}
1272 
1273 		if (tso->protocol == htons(ETHERTYPE_IP)) {
1274 			struct ip *tsoh_iph = (struct ip *)(header + tso->nh_off);
1275 			tsoh_iph->ip_len = htons(ip_length);
1276 			/* XXX We should increment ip_id, but FreeBSD doesn't
1277 			 * currently allocate extra IDs for multiple segments.
1278 			 */
1279 		} else {
1280 			struct ip6_hdr *tsoh_iph =
1281 				(struct ip6_hdr *)(header + tso->nh_off);
1282 			tsoh_iph->ip6_plen = htons(ip_length - sizeof(*tsoh_iph));
1283 		}
1284 
1285 		/* Make the header visible to the hardware. */
1286 		bus_dmamap_sync(txq->packet_dma_tag, map, BUS_DMASYNC_PREWRITE);
1287 
1288 		/* Form a descriptor for this header. */
1289 		desc = &txq->pend_desc[txq->n_pend_desc++];
1290 		efx_tx_qdesc_dma_create(txq->common,
1291 					dma_addr,
1292 					tso->header_len,
1293 					0,
1294 					desc);
1295 		id = (id + 1) & txq->ptr_mask;
1296 
1297 		tso->segs_space = UINT_MAX;
1298 	}
1299 	tso->packet_space = tso->seg_size;
1300 	txq->tso_packets++;
1301 	*idp = id;
1302 
1303 	return (0);
1304 }
1305 
1306 static int
1307 sfxge_tx_queue_tso(struct sfxge_txq *txq, struct mbuf *mbuf,
1308 		   const bus_dma_segment_t *dma_seg, int n_dma_seg,
1309 		   int vlan_tagged)
1310 {
1311 	struct sfxge_tso_state tso;
1312 	unsigned int id;
1313 	unsigned skipped = 0;
1314 
1315 	tso_start(txq, &tso, dma_seg, mbuf);
1316 
1317 	while (dma_seg->ds_len + skipped <= tso.header_len) {
1318 		skipped += dma_seg->ds_len;
1319 		--n_dma_seg;
1320 		KASSERT(n_dma_seg, ("no payload found in TSO packet"));
1321 		++dma_seg;
1322 	}
1323 	tso.in_len = dma_seg->ds_len - (tso.header_len - skipped);
1324 	tso.dma_addr = dma_seg->ds_addr + (tso.header_len - skipped);
1325 
1326 	id = (txq->added + vlan_tagged) & txq->ptr_mask;
1327 	if (__predict_false(tso_start_new_packet(txq, &tso, &id)))
1328 		return (-1);
1329 
1330 	while (1) {
1331 		tso_fill_packet_with_fragment(txq, &tso);
1332 		/* Exactly one DMA descriptor is added */
1333 		KASSERT(txq->stmp[id].flags == 0, ("stmp flags are not 0"));
1334 		id = (id + 1) & txq->ptr_mask;
1335 
1336 		/* Move onto the next fragment? */
1337 		if (tso.in_len == 0) {
1338 			--n_dma_seg;
1339 			if (n_dma_seg == 0)
1340 				break;
1341 			++dma_seg;
1342 			tso.in_len = dma_seg->ds_len;
1343 			tso.dma_addr = dma_seg->ds_addr;
1344 		}
1345 
1346 		/* End of packet? */
1347 		if ((tso.packet_space == 0) | (tso.segs_space == 0)) {
1348 			unsigned int n_fatso_opt_desc =
1349 			    (tso.fw_assisted & SFXGE_FATSOV2) ?
1350 			    EFX_TX_FATSOV2_OPT_NDESCS :
1351 			    (tso.fw_assisted & SFXGE_FATSOV1) ? 1 : 0;
1352 
1353 			/* If the queue is now full due to tiny MSS,
1354 			 * or we can't create another header, discard
1355 			 * the remainder of the input mbuf but do not
1356 			 * roll back the work we have done.
1357 			 */
1358 			if (txq->n_pend_desc + n_fatso_opt_desc +
1359 			    1 /* header */ + n_dma_seg > txq->max_pkt_desc) {
1360 				txq->tso_pdrop_too_many++;
1361 				break;
1362 			}
1363 			if (__predict_false(tso_start_new_packet(txq, &tso,
1364 								 &id))) {
1365 				txq->tso_pdrop_no_rsrc++;
1366 				break;
1367 			}
1368 		}
1369 	}
1370 
1371 	txq->tso_bursts++;
1372 	return (id);
1373 }
1374 
1375 static void
1376 sfxge_tx_qunblock(struct sfxge_txq *txq)
1377 {
1378 	struct sfxge_softc *sc;
1379 	struct sfxge_evq *evq;
1380 
1381 	sc = txq->sc;
1382 	evq = sc->evq[txq->evq_index];
1383 
1384 	SFXGE_EVQ_LOCK_ASSERT_OWNED(evq);
1385 
1386 	if (__predict_false(txq->init_state != SFXGE_TXQ_STARTED))
1387 		return;
1388 
1389 	SFXGE_TXQ_LOCK(txq);
1390 
1391 	if (txq->blocked) {
1392 		unsigned int level;
1393 
1394 		level = txq->added - txq->completed;
1395 		if (level <= SFXGE_TXQ_UNBLOCK_LEVEL(txq->entries)) {
1396 			/* reaped must be in sync with blocked */
1397 			sfxge_tx_qreap(txq);
1398 			txq->blocked = 0;
1399 		}
1400 	}
1401 
1402 	sfxge_tx_qdpl_service(txq);
1403 	/* note: lock has been dropped */
1404 }
1405 
1406 void
1407 sfxge_tx_qflush_done(struct sfxge_txq *txq)
1408 {
1409 
1410 	txq->flush_state = SFXGE_FLUSH_DONE;
1411 }
1412 
1413 static void
1414 sfxge_tx_qstop(struct sfxge_softc *sc, unsigned int index)
1415 {
1416 	struct sfxge_txq *txq;
1417 	struct sfxge_evq *evq;
1418 	unsigned int count;
1419 
1420 	SFXGE_ADAPTER_LOCK_ASSERT_OWNED(sc);
1421 
1422 	txq = sc->txq[index];
1423 	evq = sc->evq[txq->evq_index];
1424 
1425 	SFXGE_EVQ_LOCK(evq);
1426 	SFXGE_TXQ_LOCK(txq);
1427 
1428 	KASSERT(txq->init_state == SFXGE_TXQ_STARTED,
1429 	    ("txq->init_state != SFXGE_TXQ_STARTED"));
1430 
1431 	txq->init_state = SFXGE_TXQ_INITIALIZED;
1432 
1433 	if (txq->flush_state != SFXGE_FLUSH_DONE) {
1434 		txq->flush_state = SFXGE_FLUSH_PENDING;
1435 
1436 		SFXGE_EVQ_UNLOCK(evq);
1437 		SFXGE_TXQ_UNLOCK(txq);
1438 
1439 		/* Flush the transmit queue. */
1440 		if (efx_tx_qflush(txq->common) != 0) {
1441 			log(LOG_ERR, "%s: Flushing Tx queue %u failed\n",
1442 			    device_get_nameunit(sc->dev), index);
1443 			txq->flush_state = SFXGE_FLUSH_DONE;
1444 		} else {
1445 			count = 0;
1446 			do {
1447 				/* Spin for 100ms. */
1448 				DELAY(100000);
1449 				if (txq->flush_state != SFXGE_FLUSH_PENDING)
1450 					break;
1451 			} while (++count < 20);
1452 		}
1453 		SFXGE_EVQ_LOCK(evq);
1454 		SFXGE_TXQ_LOCK(txq);
1455 
1456 		KASSERT(txq->flush_state != SFXGE_FLUSH_FAILED,
1457 		    ("txq->flush_state == SFXGE_FLUSH_FAILED"));
1458 
1459 		if (txq->flush_state != SFXGE_FLUSH_DONE) {
1460 			/* Flush timeout */
1461 			log(LOG_ERR, "%s: Cannot flush Tx queue %u\n",
1462 			    device_get_nameunit(sc->dev), index);
1463 			txq->flush_state = SFXGE_FLUSH_DONE;
1464 		}
1465 	}
1466 
1467 	txq->blocked = 0;
1468 	txq->pending = txq->added;
1469 
1470 	sfxge_tx_qcomplete(txq, evq);
1471 	KASSERT(txq->completed == txq->added,
1472 	    ("txq->completed != txq->added"));
1473 
1474 	sfxge_tx_qreap(txq);
1475 	KASSERT(txq->reaped == txq->completed,
1476 	    ("txq->reaped != txq->completed"));
1477 
1478 	txq->added = 0;
1479 	txq->pending = 0;
1480 	txq->completed = 0;
1481 	txq->reaped = 0;
1482 
1483 	/* Destroy the common code transmit queue. */
1484 	efx_tx_qdestroy(txq->common);
1485 	txq->common = NULL;
1486 
1487 	efx_sram_buf_tbl_clear(sc->enp, txq->buf_base_id,
1488 	    EFX_TXQ_NBUFS(sc->txq_entries));
1489 
1490 	SFXGE_EVQ_UNLOCK(evq);
1491 	SFXGE_TXQ_UNLOCK(txq);
1492 }
1493 
1494 /*
1495  * Estimate maximum number of Tx descriptors required for TSO packet.
1496  * With minimum MSS and maximum mbuf length we might need more (even
1497  * than a ring-ful of descriptors), but this should not happen in
1498  * practice except due to deliberate attack.  In that case we will
1499  * truncate the output at a packet boundary.
1500  */
1501 static unsigned int
1502 sfxge_tx_max_pkt_desc(const struct sfxge_softc *sc, enum sfxge_txq_type type,
1503 		      unsigned int tso_fw_assisted)
1504 {
1505 	/* One descriptor for every input fragment */
1506 	unsigned int max_descs = SFXGE_TX_MAPPING_MAX_SEG;
1507 	unsigned int sw_tso_max_descs;
1508 	unsigned int fa_tso_v1_max_descs = 0;
1509 	unsigned int fa_tso_v2_max_descs = 0;
1510 
1511 	/* VLAN tagging Tx option descriptor may be required */
1512 	if (efx_nic_cfg_get(sc->enp)->enc_hw_tx_insert_vlan_enabled)
1513 		max_descs++;
1514 
1515 	if (type == SFXGE_TXQ_IP_TCP_UDP_CKSUM) {
1516 		/*
1517 		 * Plus header and payload descriptor for each output segment.
1518 		 * Minus one since header fragment is already counted.
1519 		 * Even if FATSO is used, we should be ready to fallback
1520 		 * to do it in the driver.
1521 		 */
1522 		sw_tso_max_descs = SFXGE_TSO_MAX_SEGS * 2 - 1;
1523 
1524 		/* FW assisted TSOv1 requires one more descriptor per segment
1525 		 * in comparison to SW TSO */
1526 		if (tso_fw_assisted & SFXGE_FATSOV1)
1527 			fa_tso_v1_max_descs =
1528 			    sw_tso_max_descs + SFXGE_TSO_MAX_SEGS;
1529 
1530 		/* FW assisted TSOv2 requires 3 (2 FATSO plus header) extra
1531 		 * descriptors per superframe limited by number of DMA fetches
1532 		 * per packet. The first packet header is already counted.
1533 		 */
1534 		if (tso_fw_assisted & SFXGE_FATSOV2) {
1535 			fa_tso_v2_max_descs =
1536 			    howmany(SFXGE_TX_MAPPING_MAX_SEG,
1537 				    EFX_TX_FATSOV2_DMA_SEGS_PER_PKT_MAX - 1) *
1538 			    (EFX_TX_FATSOV2_OPT_NDESCS + 1) - 1;
1539 		}
1540 
1541 		max_descs += MAX(sw_tso_max_descs,
1542 				 MAX(fa_tso_v1_max_descs, fa_tso_v2_max_descs));
1543 	}
1544 
1545 	return (max_descs);
1546 }
1547 
1548 static int
1549 sfxge_tx_qstart(struct sfxge_softc *sc, unsigned int index)
1550 {
1551 	struct sfxge_txq *txq;
1552 	efsys_mem_t *esmp;
1553 	uint16_t flags;
1554 	unsigned int tso_fw_assisted;
1555 	struct sfxge_evq *evq;
1556 	unsigned int desc_index;
1557 	int rc;
1558 
1559 	SFXGE_ADAPTER_LOCK_ASSERT_OWNED(sc);
1560 
1561 	txq = sc->txq[index];
1562 	esmp = &txq->mem;
1563 	evq = sc->evq[txq->evq_index];
1564 
1565 	KASSERT(txq->init_state == SFXGE_TXQ_INITIALIZED,
1566 	    ("txq->init_state != SFXGE_TXQ_INITIALIZED"));
1567 	KASSERT(evq->init_state == SFXGE_EVQ_STARTED,
1568 	    ("evq->init_state != SFXGE_EVQ_STARTED"));
1569 
1570 	/* Program the buffer table. */
1571 	if ((rc = efx_sram_buf_tbl_set(sc->enp, txq->buf_base_id, esmp,
1572 	    EFX_TXQ_NBUFS(sc->txq_entries))) != 0)
1573 		return (rc);
1574 
1575 	/* Determine the kind of queue we are creating. */
1576 	tso_fw_assisted = 0;
1577 	switch (txq->type) {
1578 	case SFXGE_TXQ_NON_CKSUM:
1579 		flags = 0;
1580 		break;
1581 	case SFXGE_TXQ_IP_CKSUM:
1582 		flags = EFX_TXQ_CKSUM_IPV4;
1583 		break;
1584 	case SFXGE_TXQ_IP_TCP_UDP_CKSUM:
1585 		flags = EFX_TXQ_CKSUM_IPV4 | EFX_TXQ_CKSUM_TCPUDP;
1586 		tso_fw_assisted = sc->tso_fw_assisted;
1587 		if (tso_fw_assisted & SFXGE_FATSOV2)
1588 			flags |= EFX_TXQ_FATSOV2;
1589 		break;
1590 	default:
1591 		KASSERT(0, ("Impossible TX queue"));
1592 		flags = 0;
1593 		break;
1594 	}
1595 
1596 	/* Create the common code transmit queue. */
1597 	if ((rc = efx_tx_qcreate(sc->enp, index, txq->type, esmp,
1598 	    sc->txq_entries, txq->buf_base_id, flags, evq->common,
1599 	    &txq->common, &desc_index)) != 0) {
1600 		/* Retry if no FATSOv2 resources, otherwise fail */
1601 		if ((rc != ENOSPC) || (~flags & EFX_TXQ_FATSOV2))
1602 			goto fail;
1603 
1604 		/* Looks like all FATSOv2 contexts are used */
1605 		flags &= ~EFX_TXQ_FATSOV2;
1606 		tso_fw_assisted &= ~SFXGE_FATSOV2;
1607 		if ((rc = efx_tx_qcreate(sc->enp, index, txq->type, esmp,
1608 		    sc->txq_entries, txq->buf_base_id, flags, evq->common,
1609 		    &txq->common, &desc_index)) != 0)
1610 			goto fail;
1611 	}
1612 
1613 	/* Initialise queue descriptor indexes */
1614 	txq->added = txq->pending = txq->completed = txq->reaped = desc_index;
1615 
1616 	SFXGE_TXQ_LOCK(txq);
1617 
1618 	/* Enable the transmit queue. */
1619 	efx_tx_qenable(txq->common);
1620 
1621 	txq->init_state = SFXGE_TXQ_STARTED;
1622 	txq->flush_state = SFXGE_FLUSH_REQUIRED;
1623 	txq->tso_fw_assisted = tso_fw_assisted;
1624 
1625 	txq->max_pkt_desc = sfxge_tx_max_pkt_desc(sc, txq->type,
1626 						  tso_fw_assisted);
1627 
1628 	txq->hw_vlan_tci = 0;
1629 
1630 	SFXGE_TXQ_UNLOCK(txq);
1631 
1632 	return (0);
1633 
1634 fail:
1635 	efx_sram_buf_tbl_clear(sc->enp, txq->buf_base_id,
1636 	    EFX_TXQ_NBUFS(sc->txq_entries));
1637 	return (rc);
1638 }
1639 
1640 void
1641 sfxge_tx_stop(struct sfxge_softc *sc)
1642 {
1643 	int index;
1644 
1645 	index = sc->txq_count;
1646 	while (--index >= 0)
1647 		sfxge_tx_qstop(sc, index);
1648 
1649 	/* Tear down the transmit module */
1650 	efx_tx_fini(sc->enp);
1651 }
1652 
1653 int
1654 sfxge_tx_start(struct sfxge_softc *sc)
1655 {
1656 	int index;
1657 	int rc;
1658 
1659 	/* Initialize the common code transmit module. */
1660 	if ((rc = efx_tx_init(sc->enp)) != 0)
1661 		return (rc);
1662 
1663 	for (index = 0; index < sc->txq_count; index++) {
1664 		if ((rc = sfxge_tx_qstart(sc, index)) != 0)
1665 			goto fail;
1666 	}
1667 
1668 	return (0);
1669 
1670 fail:
1671 	while (--index >= 0)
1672 		sfxge_tx_qstop(sc, index);
1673 
1674 	efx_tx_fini(sc->enp);
1675 
1676 	return (rc);
1677 }
1678 
1679 static int
1680 sfxge_txq_stat_init(struct sfxge_txq *txq, struct sysctl_oid *txq_node)
1681 {
1682 	struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(txq->sc->dev);
1683 	struct sysctl_oid *stat_node;
1684 	unsigned int id;
1685 
1686 	stat_node = SYSCTL_ADD_NODE(ctx, SYSCTL_CHILDREN(txq_node), OID_AUTO,
1687 				    "stats", CTLFLAG_RD, NULL,
1688 				    "Tx queue statistics");
1689 	if (stat_node == NULL)
1690 		return (ENOMEM);
1691 
1692 	for (id = 0; id < nitems(sfxge_tx_stats); id++) {
1693 		SYSCTL_ADD_ULONG(
1694 		    ctx, SYSCTL_CHILDREN(stat_node), OID_AUTO,
1695 		    sfxge_tx_stats[id].name, CTLFLAG_RD | CTLFLAG_STATS,
1696 		    (unsigned long *)((caddr_t)txq + sfxge_tx_stats[id].offset),
1697 		    "");
1698 	}
1699 
1700 	return (0);
1701 }
1702 
1703 /**
1704  * Destroy a transmit queue.
1705  */
1706 static void
1707 sfxge_tx_qfini(struct sfxge_softc *sc, unsigned int index)
1708 {
1709 	struct sfxge_txq *txq;
1710 	unsigned int nmaps;
1711 
1712 	txq = sc->txq[index];
1713 
1714 	KASSERT(txq->init_state == SFXGE_TXQ_INITIALIZED,
1715 	    ("txq->init_state != SFXGE_TXQ_INITIALIZED"));
1716 
1717 	if (txq->type == SFXGE_TXQ_IP_TCP_UDP_CKSUM)
1718 		tso_fini(txq);
1719 
1720 	/* Free the context arrays. */
1721 	free(txq->pend_desc, M_SFXGE);
1722 	nmaps = sc->txq_entries;
1723 	while (nmaps-- != 0)
1724 		bus_dmamap_destroy(txq->packet_dma_tag, txq->stmp[nmaps].map);
1725 	free(txq->stmp, M_SFXGE);
1726 
1727 	/* Release DMA memory mapping. */
1728 	sfxge_dma_free(&txq->mem);
1729 
1730 	sc->txq[index] = NULL;
1731 
1732 	SFXGE_TXQ_LOCK_DESTROY(txq);
1733 
1734 	free(txq, M_SFXGE);
1735 }
1736 
1737 static int
1738 sfxge_tx_qinit(struct sfxge_softc *sc, unsigned int txq_index,
1739 	       enum sfxge_txq_type type, unsigned int evq_index)
1740 {
1741 	const efx_nic_cfg_t *encp = efx_nic_cfg_get(sc->enp);
1742 	char name[16];
1743 	struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(sc->dev);
1744 	struct sysctl_oid *txq_node;
1745 	struct sfxge_txq *txq;
1746 	struct sfxge_evq *evq;
1747 	struct sfxge_tx_dpl *stdp;
1748 	struct sysctl_oid *dpl_node;
1749 	efsys_mem_t *esmp;
1750 	unsigned int nmaps;
1751 	int rc;
1752 
1753 	txq = malloc(sizeof(struct sfxge_txq), M_SFXGE, M_ZERO | M_WAITOK);
1754 	txq->sc = sc;
1755 	txq->entries = sc->txq_entries;
1756 	txq->ptr_mask = txq->entries - 1;
1757 
1758 	sc->txq[txq_index] = txq;
1759 	esmp = &txq->mem;
1760 
1761 	evq = sc->evq[evq_index];
1762 
1763 	/* Allocate and zero DMA space for the descriptor ring. */
1764 	if ((rc = sfxge_dma_alloc(sc, EFX_TXQ_SIZE(sc->txq_entries), esmp)) != 0)
1765 		return (rc);
1766 
1767 	/* Allocate buffer table entries. */
1768 	sfxge_sram_buf_tbl_alloc(sc, EFX_TXQ_NBUFS(sc->txq_entries),
1769 				 &txq->buf_base_id);
1770 
1771 	/* Create a DMA tag for packet mappings. */
1772 	if (bus_dma_tag_create(sc->parent_dma_tag, 1,
1773 	    encp->enc_tx_dma_desc_boundary,
1774 	    MIN(0x3FFFFFFFFFFFUL, BUS_SPACE_MAXADDR), BUS_SPACE_MAXADDR, NULL,
1775 	    NULL, 0x11000, SFXGE_TX_MAPPING_MAX_SEG,
1776 	    encp->enc_tx_dma_desc_size_max, 0, NULL, NULL,
1777 	    &txq->packet_dma_tag) != 0) {
1778 		device_printf(sc->dev, "Couldn't allocate txq DMA tag\n");
1779 		rc = ENOMEM;
1780 		goto fail;
1781 	}
1782 
1783 	/* Allocate pending descriptor array for batching writes. */
1784 	txq->pend_desc = malloc(sizeof(efx_desc_t) * sc->txq_entries,
1785 				M_SFXGE, M_ZERO | M_WAITOK);
1786 
1787 	/* Allocate and initialise mbuf DMA mapping array. */
1788 	txq->stmp = malloc(sizeof(struct sfxge_tx_mapping) * sc->txq_entries,
1789 	    M_SFXGE, M_ZERO | M_WAITOK);
1790 	for (nmaps = 0; nmaps < sc->txq_entries; nmaps++) {
1791 		rc = bus_dmamap_create(txq->packet_dma_tag, 0,
1792 				       &txq->stmp[nmaps].map);
1793 		if (rc != 0)
1794 			goto fail2;
1795 	}
1796 
1797 	snprintf(name, sizeof(name), "%u", txq_index);
1798 	txq_node = SYSCTL_ADD_NODE(ctx, SYSCTL_CHILDREN(sc->txqs_node),
1799 				   OID_AUTO, name, CTLFLAG_RD, NULL, "");
1800 	if (txq_node == NULL) {
1801 		rc = ENOMEM;
1802 		goto fail_txq_node;
1803 	}
1804 
1805 	if (type == SFXGE_TXQ_IP_TCP_UDP_CKSUM &&
1806 	    (rc = tso_init(txq)) != 0)
1807 		goto fail3;
1808 
1809 	/* Initialize the deferred packet list. */
1810 	stdp = &txq->dpl;
1811 	stdp->std_put_max = sfxge_tx_dpl_put_max;
1812 	stdp->std_get_max = sfxge_tx_dpl_get_max;
1813 	stdp->std_get_non_tcp_max = sfxge_tx_dpl_get_non_tcp_max;
1814 	stdp->std_getp = &stdp->std_get;
1815 
1816 	SFXGE_TXQ_LOCK_INIT(txq, device_get_nameunit(sc->dev), txq_index);
1817 
1818 	dpl_node = SYSCTL_ADD_NODE(ctx, SYSCTL_CHILDREN(txq_node), OID_AUTO,
1819 				   "dpl", CTLFLAG_RD, NULL,
1820 				   "Deferred packet list statistics");
1821 	if (dpl_node == NULL) {
1822 		rc = ENOMEM;
1823 		goto fail_dpl_node;
1824 	}
1825 
1826 	SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(dpl_node), OID_AUTO,
1827 			"get_count", CTLFLAG_RD | CTLFLAG_STATS,
1828 			&stdp->std_get_count, 0, "");
1829 	SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(dpl_node), OID_AUTO,
1830 			"get_non_tcp_count", CTLFLAG_RD | CTLFLAG_STATS,
1831 			&stdp->std_get_non_tcp_count, 0, "");
1832 	SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(dpl_node), OID_AUTO,
1833 			"get_hiwat", CTLFLAG_RD | CTLFLAG_STATS,
1834 			&stdp->std_get_hiwat, 0, "");
1835 	SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(dpl_node), OID_AUTO,
1836 			"put_hiwat", CTLFLAG_RD | CTLFLAG_STATS,
1837 			&stdp->std_put_hiwat, 0, "");
1838 
1839 	rc = sfxge_txq_stat_init(txq, txq_node);
1840 	if (rc != 0)
1841 		goto fail_txq_stat_init;
1842 
1843 	txq->type = type;
1844 	txq->evq_index = evq_index;
1845 	txq->init_state = SFXGE_TXQ_INITIALIZED;
1846 
1847 	return (0);
1848 
1849 fail_txq_stat_init:
1850 fail_dpl_node:
1851 fail3:
1852 fail_txq_node:
1853 	free(txq->pend_desc, M_SFXGE);
1854 fail2:
1855 	while (nmaps-- != 0)
1856 		bus_dmamap_destroy(txq->packet_dma_tag, txq->stmp[nmaps].map);
1857 	free(txq->stmp, M_SFXGE);
1858 	bus_dma_tag_destroy(txq->packet_dma_tag);
1859 
1860 fail:
1861 	sfxge_dma_free(esmp);
1862 
1863 	return (rc);
1864 }
1865 
1866 static int
1867 sfxge_tx_stat_handler(SYSCTL_HANDLER_ARGS)
1868 {
1869 	struct sfxge_softc *sc = arg1;
1870 	unsigned int id = arg2;
1871 	unsigned long sum;
1872 	unsigned int index;
1873 
1874 	/* Sum across all TX queues */
1875 	sum = 0;
1876 	for (index = 0; index < sc->txq_count; index++)
1877 		sum += *(unsigned long *)((caddr_t)sc->txq[index] +
1878 					  sfxge_tx_stats[id].offset);
1879 
1880 	return (SYSCTL_OUT(req, &sum, sizeof(sum)));
1881 }
1882 
1883 static void
1884 sfxge_tx_stat_init(struct sfxge_softc *sc)
1885 {
1886 	struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(sc->dev);
1887 	struct sysctl_oid_list *stat_list;
1888 	unsigned int id;
1889 
1890 	stat_list = SYSCTL_CHILDREN(sc->stats_node);
1891 
1892 	for (id = 0; id < nitems(sfxge_tx_stats); id++) {
1893 		SYSCTL_ADD_PROC(
1894 			ctx, stat_list,
1895 			OID_AUTO, sfxge_tx_stats[id].name,
1896 			CTLTYPE_ULONG|CTLFLAG_RD,
1897 			sc, id, sfxge_tx_stat_handler, "LU",
1898 			"");
1899 	}
1900 }
1901 
1902 uint64_t
1903 sfxge_tx_get_drops(struct sfxge_softc *sc)
1904 {
1905 	unsigned int index;
1906 	uint64_t drops = 0;
1907 	struct sfxge_txq *txq;
1908 
1909 	/* Sum across all TX queues */
1910 	for (index = 0; index < sc->txq_count; index++) {
1911 		txq = sc->txq[index];
1912 		/*
1913 		 * In theory, txq->put_overflow and txq->netdown_drops
1914 		 * should use atomic operation and other should be
1915 		 * obtained under txq lock, but it is just statistics.
1916 		 */
1917 		drops += txq->drops + txq->get_overflow +
1918 			 txq->get_non_tcp_overflow +
1919 			 txq->put_overflow + txq->netdown_drops +
1920 			 txq->tso_pdrop_too_many + txq->tso_pdrop_no_rsrc;
1921 	}
1922 	return (drops);
1923 }
1924 
1925 void
1926 sfxge_tx_fini(struct sfxge_softc *sc)
1927 {
1928 	int index;
1929 
1930 	index = sc->txq_count;
1931 	while (--index >= 0)
1932 		sfxge_tx_qfini(sc, index);
1933 
1934 	sc->txq_count = 0;
1935 }
1936 
1937 
1938 int
1939 sfxge_tx_init(struct sfxge_softc *sc)
1940 {
1941 	const efx_nic_cfg_t *encp = efx_nic_cfg_get(sc->enp);
1942 	struct sfxge_intr *intr;
1943 	int index;
1944 	int rc;
1945 
1946 	intr = &sc->intr;
1947 
1948 	KASSERT(intr->state == SFXGE_INTR_INITIALIZED,
1949 	    ("intr->state != SFXGE_INTR_INITIALIZED"));
1950 
1951 	if (sfxge_tx_dpl_get_max <= 0) {
1952 		log(LOG_ERR, "%s=%d must be greater than 0",
1953 		    SFXGE_PARAM_TX_DPL_GET_MAX, sfxge_tx_dpl_get_max);
1954 		rc = EINVAL;
1955 		goto fail_tx_dpl_get_max;
1956 	}
1957 	if (sfxge_tx_dpl_get_non_tcp_max <= 0) {
1958 		log(LOG_ERR, "%s=%d must be greater than 0",
1959 		    SFXGE_PARAM_TX_DPL_GET_NON_TCP_MAX,
1960 		    sfxge_tx_dpl_get_non_tcp_max);
1961 		rc = EINVAL;
1962 		goto fail_tx_dpl_get_non_tcp_max;
1963 	}
1964 	if (sfxge_tx_dpl_put_max < 0) {
1965 		log(LOG_ERR, "%s=%d must be greater or equal to 0",
1966 		    SFXGE_PARAM_TX_DPL_PUT_MAX, sfxge_tx_dpl_put_max);
1967 		rc = EINVAL;
1968 		goto fail_tx_dpl_put_max;
1969 	}
1970 
1971 	sc->txq_count = SFXGE_TXQ_NTYPES - 1 + sc->intr.n_alloc;
1972 
1973 	sc->tso_fw_assisted = sfxge_tso_fw_assisted;
1974 	if ((~encp->enc_features & EFX_FEATURE_FW_ASSISTED_TSO) ||
1975 	    (!encp->enc_fw_assisted_tso_enabled))
1976 		sc->tso_fw_assisted &= ~SFXGE_FATSOV1;
1977 	if ((~encp->enc_features & EFX_FEATURE_FW_ASSISTED_TSO_V2) ||
1978 	    (!encp->enc_fw_assisted_tso_v2_enabled))
1979 		sc->tso_fw_assisted &= ~SFXGE_FATSOV2;
1980 
1981 	sc->txqs_node = SYSCTL_ADD_NODE(
1982 		device_get_sysctl_ctx(sc->dev),
1983 		SYSCTL_CHILDREN(device_get_sysctl_tree(sc->dev)),
1984 		OID_AUTO, "txq", CTLFLAG_RD, NULL, "Tx queues");
1985 	if (sc->txqs_node == NULL) {
1986 		rc = ENOMEM;
1987 		goto fail_txq_node;
1988 	}
1989 
1990 	/* Initialize the transmit queues */
1991 	if ((rc = sfxge_tx_qinit(sc, SFXGE_TXQ_NON_CKSUM,
1992 	    SFXGE_TXQ_NON_CKSUM, 0)) != 0)
1993 		goto fail;
1994 
1995 	if ((rc = sfxge_tx_qinit(sc, SFXGE_TXQ_IP_CKSUM,
1996 	    SFXGE_TXQ_IP_CKSUM, 0)) != 0)
1997 		goto fail2;
1998 
1999 	for (index = 0;
2000 	     index < sc->txq_count - SFXGE_TXQ_NTYPES + 1;
2001 	     index++) {
2002 		if ((rc = sfxge_tx_qinit(sc, SFXGE_TXQ_NTYPES - 1 + index,
2003 		    SFXGE_TXQ_IP_TCP_UDP_CKSUM, index)) != 0)
2004 			goto fail3;
2005 	}
2006 
2007 	sfxge_tx_stat_init(sc);
2008 
2009 	return (0);
2010 
2011 fail3:
2012 	while (--index >= 0)
2013 		sfxge_tx_qfini(sc, SFXGE_TXQ_IP_TCP_UDP_CKSUM + index);
2014 
2015 	sfxge_tx_qfini(sc, SFXGE_TXQ_IP_CKSUM);
2016 
2017 fail2:
2018 	sfxge_tx_qfini(sc, SFXGE_TXQ_NON_CKSUM);
2019 
2020 fail:
2021 fail_txq_node:
2022 	sc->txq_count = 0;
2023 fail_tx_dpl_put_max:
2024 fail_tx_dpl_get_non_tcp_max:
2025 fail_tx_dpl_get_max:
2026 	return (rc);
2027 }
2028