xref: /dpdk/drivers/net/sfc/sfc_ef100_tx.c (revision 081e42dab11d1add2d038fdf2bd4c86b20043d08)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  *
3  * Copyright(c) 2019-2021 Xilinx, Inc.
4  * Copyright(c) 2018-2019 Solarflare Communications Inc.
5  *
6  * This software was jointly developed between OKTET Labs (under contract
7  * for Solarflare) and Solarflare Communications, Inc.
8  */
9 
10 #include <stdbool.h>
11 
12 #include <rte_mbuf.h>
13 #include <rte_mbuf_dyn.h>
14 #include <rte_io.h>
15 #include <rte_net.h>
16 
17 #include "efx.h"
18 #include "efx_types.h"
19 #include "efx_regs.h"
20 #include "efx_regs_ef100.h"
21 
22 #include "sfc_debug.h"
23 #include "sfc_dp_tx.h"
24 #include "sfc_tweak.h"
25 #include "sfc_kvargs.h"
26 #include "sfc_ef100.h"
27 
28 
29 #define sfc_ef100_tx_err(_txq, ...) \
30 	SFC_DP_LOG(SFC_KVARG_DATAPATH_EF100, ERR, &(_txq)->dp.dpq, __VA_ARGS__)
31 
32 #define sfc_ef100_tx_debug(_txq, ...) \
33 	SFC_DP_LOG(SFC_KVARG_DATAPATH_EF100, DEBUG, &(_txq)->dp.dpq, \
34 		   __VA_ARGS__)
35 
36 
37 /** Maximum length of the send descriptor data */
38 #define SFC_EF100_TX_SEND_DESC_LEN_MAX \
39 	((1u << ESF_GZ_TX_SEND_LEN_WIDTH) - 1)
40 
41 /** Maximum length of the segment descriptor data */
42 #define SFC_EF100_TX_SEG_DESC_LEN_MAX \
43 	((1u << ESF_GZ_TX_SEG_LEN_WIDTH) - 1)
44 
45 /**
46  * Maximum number of descriptors/buffers in the Tx ring.
47  * It should guarantee that corresponding event queue never overfill.
48  * EF100 native datapath uses event queue of the same size as Tx queue.
49  * Maximum number of events on datapath can be estimated as number of
50  * Tx queue entries (one event per Tx buffer in the worst case) plus
51  * Tx error and flush events.
52  */
53 #define SFC_EF100_TXQ_LIMIT(_ndesc) \
54 	((_ndesc) - 1 /* head must not step on tail */ - \
55 	 1 /* Rx error */ - 1 /* flush */)
56 
57 struct sfc_ef100_tx_sw_desc {
58 	struct rte_mbuf			*mbuf;
59 };
60 
61 struct sfc_ef100_txq {
62 	unsigned int			flags;
63 #define SFC_EF100_TXQ_STARTED		0x1
64 #define SFC_EF100_TXQ_NOT_RUNNING	0x2
65 #define SFC_EF100_TXQ_EXCEPTION		0x4
66 
67 	unsigned int			ptr_mask;
68 	unsigned int			added;
69 	unsigned int			completed;
70 	unsigned int			max_fill_level;
71 	unsigned int			free_thresh;
72 	struct sfc_ef100_tx_sw_desc	*sw_ring;
73 	efx_oword_t			*txq_hw_ring;
74 	volatile void			*doorbell;
75 
76 	/* Completion/reap */
77 	unsigned int			evq_read_ptr;
78 	unsigned int			evq_phase_bit_shift;
79 	volatile efx_qword_t		*evq_hw_ring;
80 
81 	uint16_t			tso_tcp_header_offset_limit;
82 	uint16_t			tso_max_nb_header_descs;
83 	uint16_t			tso_max_header_len;
84 	uint16_t			tso_max_nb_payload_descs;
85 	uint32_t			tso_max_payload_len;
86 	uint32_t			tso_max_nb_outgoing_frames;
87 
88 	/* Datapath transmit queue anchor */
89 	struct sfc_dp_txq		dp;
90 };
91 
92 static inline struct sfc_ef100_txq *
93 sfc_ef100_txq_by_dp_txq(struct sfc_dp_txq *dp_txq)
94 {
95 	return container_of(dp_txq, struct sfc_ef100_txq, dp);
96 }
97 
98 static int
99 sfc_ef100_tx_prepare_pkt_tso(struct sfc_ef100_txq * const txq,
100 			     struct rte_mbuf *m)
101 {
102 	size_t header_len = ((m->ol_flags & PKT_TX_TUNNEL_MASK) ?
103 			     m->outer_l2_len + m->outer_l3_len : 0) +
104 			    m->l2_len + m->l3_len + m->l4_len;
105 	size_t payload_len = m->pkt_len - header_len;
106 	unsigned long mss_conformant_max_payload_len;
107 	unsigned int nb_payload_descs;
108 
109 #ifdef RTE_LIBRTE_SFC_EFX_DEBUG
110 	switch (m->ol_flags & PKT_TX_TUNNEL_MASK) {
111 	case 0:
112 		/* FALLTHROUGH */
113 	case PKT_TX_TUNNEL_VXLAN:
114 		/* FALLTHROUGH */
115 	case PKT_TX_TUNNEL_GENEVE:
116 		break;
117 	default:
118 		return ENOTSUP;
119 	}
120 #endif
121 
122 	mss_conformant_max_payload_len =
123 		m->tso_segsz * txq->tso_max_nb_outgoing_frames;
124 
125 	/*
126 	 * Don't really want to know exact number of payload segments.
127 	 * Just use total number of segments as upper limit. Practically
128 	 * maximum number of payload segments is significantly bigger
129 	 * than maximum number header segments, so we can neglect header
130 	 * segments excluded total number of segments to estimate number
131 	 * of payload segments required.
132 	 */
133 	nb_payload_descs = m->nb_segs;
134 
135 	/*
136 	 * Carry out multiple independent checks using bitwise OR
137 	 * to avoid unnecessary conditional branching.
138 	 */
139 	if (unlikely((header_len > txq->tso_max_header_len) |
140 		     (nb_payload_descs > txq->tso_max_nb_payload_descs) |
141 		     (payload_len > txq->tso_max_payload_len) |
142 		     (payload_len > mss_conformant_max_payload_len) |
143 		     (m->pkt_len == header_len)))
144 		return EINVAL;
145 
146 	return 0;
147 }
148 
149 static uint16_t
150 sfc_ef100_tx_prepare_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
151 			  uint16_t nb_pkts)
152 {
153 	struct sfc_ef100_txq * const txq = sfc_ef100_txq_by_dp_txq(tx_queue);
154 	uint16_t i;
155 
156 	for (i = 0; i < nb_pkts; i++) {
157 		struct rte_mbuf *m = tx_pkts[i];
158 		unsigned int max_nb_header_segs = 0;
159 		bool calc_phdr_cksum = false;
160 		int ret;
161 
162 		/*
163 		 * Partial checksum offload is used in the case of
164 		 * inner TCP/UDP checksum offload. It requires
165 		 * pseudo-header checksum which is calculated below,
166 		 * but requires contiguous packet headers.
167 		 */
168 		if ((m->ol_flags & PKT_TX_TUNNEL_MASK) &&
169 		    (m->ol_flags & PKT_TX_L4_MASK)) {
170 			calc_phdr_cksum = true;
171 			max_nb_header_segs = 1;
172 		} else if (m->ol_flags & PKT_TX_TCP_SEG) {
173 			max_nb_header_segs = txq->tso_max_nb_header_descs;
174 		}
175 
176 		ret = sfc_dp_tx_prepare_pkt(m, max_nb_header_segs, 0,
177 					    txq->tso_tcp_header_offset_limit,
178 					    txq->max_fill_level, 1, 0);
179 		if (unlikely(ret != 0)) {
180 			rte_errno = ret;
181 			break;
182 		}
183 
184 		if (m->ol_flags & PKT_TX_TCP_SEG) {
185 			ret = sfc_ef100_tx_prepare_pkt_tso(txq, m);
186 			if (unlikely(ret != 0)) {
187 				rte_errno = ret;
188 				break;
189 			}
190 		} else if (m->nb_segs > EFX_MASK32(ESF_GZ_TX_SEND_NUM_SEGS)) {
191 			rte_errno = EINVAL;
192 			break;
193 		}
194 
195 		if (calc_phdr_cksum) {
196 			/*
197 			 * Full checksum offload does IPv4 header checksum
198 			 * and does not require any assistance.
199 			 */
200 			ret = rte_net_intel_cksum_flags_prepare(m,
201 					m->ol_flags & ~PKT_TX_IP_CKSUM);
202 			if (unlikely(ret != 0)) {
203 				rte_errno = -ret;
204 				break;
205 			}
206 		}
207 	}
208 
209 	return i;
210 }
211 
212 static bool
213 sfc_ef100_tx_get_event(struct sfc_ef100_txq *txq, efx_qword_t *ev)
214 {
215 	volatile efx_qword_t *evq_hw_ring = txq->evq_hw_ring;
216 
217 	/*
218 	 * Exception flag is set when reap is done.
219 	 * It is never done twice per packet burst get, and absence of
220 	 * the flag is checked on burst get entry.
221 	 */
222 	SFC_ASSERT((txq->flags & SFC_EF100_TXQ_EXCEPTION) == 0);
223 
224 	*ev = evq_hw_ring[txq->evq_read_ptr & txq->ptr_mask];
225 
226 	if (!sfc_ef100_ev_present(ev,
227 			(txq->evq_read_ptr >> txq->evq_phase_bit_shift) & 1))
228 		return false;
229 
230 	if (unlikely(!sfc_ef100_ev_type_is(ev,
231 					   ESE_GZ_EF100_EV_TX_COMPLETION))) {
232 		/*
233 		 * Do not move read_ptr to keep the event for exception
234 		 * handling by the control path.
235 		 */
236 		txq->flags |= SFC_EF100_TXQ_EXCEPTION;
237 		sfc_ef100_tx_err(txq,
238 			"TxQ exception at EvQ ptr %u(%#x), event %08x:%08x",
239 			txq->evq_read_ptr, txq->evq_read_ptr & txq->ptr_mask,
240 			EFX_QWORD_FIELD(*ev, EFX_DWORD_1),
241 			EFX_QWORD_FIELD(*ev, EFX_DWORD_0));
242 		return false;
243 	}
244 
245 	sfc_ef100_tx_debug(txq, "TxQ got event %08x:%08x at %u (%#x)",
246 			   EFX_QWORD_FIELD(*ev, EFX_DWORD_1),
247 			   EFX_QWORD_FIELD(*ev, EFX_DWORD_0),
248 			   txq->evq_read_ptr,
249 			   txq->evq_read_ptr & txq->ptr_mask);
250 
251 	txq->evq_read_ptr++;
252 	return true;
253 }
254 
255 static unsigned int
256 sfc_ef100_tx_process_events(struct sfc_ef100_txq *txq)
257 {
258 	unsigned int num_descs = 0;
259 	efx_qword_t tx_ev;
260 
261 	while (sfc_ef100_tx_get_event(txq, &tx_ev))
262 		num_descs += EFX_QWORD_FIELD(tx_ev, ESF_GZ_EV_TXCMPL_NUM_DESC);
263 
264 	return num_descs;
265 }
266 
267 static void
268 sfc_ef100_tx_reap_num_descs(struct sfc_ef100_txq *txq, unsigned int num_descs)
269 {
270 	if (num_descs > 0) {
271 		unsigned int completed = txq->completed;
272 		unsigned int pending = completed + num_descs;
273 		struct rte_mbuf *bulk[SFC_TX_REAP_BULK_SIZE];
274 		unsigned int nb = 0;
275 
276 		do {
277 			struct sfc_ef100_tx_sw_desc *txd;
278 			struct rte_mbuf *m;
279 
280 			txd = &txq->sw_ring[completed & txq->ptr_mask];
281 			if (txd->mbuf == NULL)
282 				continue;
283 
284 			m = rte_pktmbuf_prefree_seg(txd->mbuf);
285 			if (m == NULL)
286 				continue;
287 
288 			txd->mbuf = NULL;
289 
290 			if (nb == RTE_DIM(bulk) ||
291 			    (nb != 0 && m->pool != bulk[0]->pool)) {
292 				rte_mempool_put_bulk(bulk[0]->pool,
293 						     (void *)bulk, nb);
294 				nb = 0;
295 			}
296 
297 			bulk[nb++] = m;
298 		} while (++completed != pending);
299 
300 		if (nb != 0)
301 			rte_mempool_put_bulk(bulk[0]->pool, (void *)bulk, nb);
302 
303 		txq->completed = completed;
304 	}
305 }
306 
307 static void
308 sfc_ef100_tx_reap(struct sfc_ef100_txq *txq)
309 {
310 	sfc_ef100_tx_reap_num_descs(txq, sfc_ef100_tx_process_events(txq));
311 }
312 
313 static void
314 sfc_ef100_tx_qdesc_prefix_create(const struct rte_mbuf *m, efx_oword_t *tx_desc)
315 {
316 	efx_mport_id_t *mport_id =
317 		RTE_MBUF_DYNFIELD(m, sfc_dp_mport_offset, efx_mport_id_t *);
318 
319 	EFX_POPULATE_OWORD_3(*tx_desc,
320 			ESF_GZ_TX_PREFIX_EGRESS_MPORT,
321 			mport_id->id,
322 			ESF_GZ_TX_PREFIX_EGRESS_MPORT_EN, 1,
323 			ESF_GZ_TX_DESC_TYPE, ESE_GZ_TX_DESC_TYPE_PREFIX);
324 }
325 
326 static uint8_t
327 sfc_ef100_tx_qdesc_cso_inner_l3(uint64_t tx_tunnel)
328 {
329 	uint8_t inner_l3;
330 
331 	switch (tx_tunnel) {
332 	case PKT_TX_TUNNEL_VXLAN:
333 		inner_l3 = ESE_GZ_TX_DESC_CS_INNER_L3_VXLAN;
334 		break;
335 	case PKT_TX_TUNNEL_GENEVE:
336 		inner_l3 = ESE_GZ_TX_DESC_CS_INNER_L3_GENEVE;
337 		break;
338 	default:
339 		inner_l3 = ESE_GZ_TX_DESC_CS_INNER_L3_OFF;
340 		break;
341 	}
342 	return inner_l3;
343 }
344 
345 static void
346 sfc_ef100_tx_qdesc_send_create(const struct rte_mbuf *m, efx_oword_t *tx_desc)
347 {
348 	bool outer_l3;
349 	bool outer_l4;
350 	uint8_t inner_l3;
351 	uint8_t partial_en;
352 	uint16_t part_cksum_w;
353 	uint16_t l4_offset_w;
354 
355 	if ((m->ol_flags & PKT_TX_TUNNEL_MASK) == 0) {
356 		outer_l3 = (m->ol_flags & PKT_TX_IP_CKSUM);
357 		outer_l4 = (m->ol_flags & PKT_TX_L4_MASK);
358 		inner_l3 = ESE_GZ_TX_DESC_CS_INNER_L3_OFF;
359 		partial_en = ESE_GZ_TX_DESC_CSO_PARTIAL_EN_OFF;
360 		part_cksum_w = 0;
361 		l4_offset_w = 0;
362 	} else {
363 		outer_l3 = (m->ol_flags & PKT_TX_OUTER_IP_CKSUM);
364 		outer_l4 = (m->ol_flags & PKT_TX_OUTER_UDP_CKSUM);
365 		inner_l3 = sfc_ef100_tx_qdesc_cso_inner_l3(m->ol_flags &
366 							   PKT_TX_TUNNEL_MASK);
367 
368 		switch (m->ol_flags & PKT_TX_L4_MASK) {
369 		case PKT_TX_TCP_CKSUM:
370 			partial_en = ESE_GZ_TX_DESC_CSO_PARTIAL_EN_TCP;
371 			part_cksum_w = offsetof(struct rte_tcp_hdr, cksum) >> 1;
372 			break;
373 		case PKT_TX_UDP_CKSUM:
374 			partial_en = ESE_GZ_TX_DESC_CSO_PARTIAL_EN_UDP;
375 			part_cksum_w = offsetof(struct rte_udp_hdr,
376 						dgram_cksum) >> 1;
377 			break;
378 		default:
379 			partial_en = ESE_GZ_TX_DESC_CSO_PARTIAL_EN_OFF;
380 			part_cksum_w = 0;
381 			break;
382 		}
383 		l4_offset_w = (m->outer_l2_len + m->outer_l3_len +
384 				m->l2_len + m->l3_len) >> 1;
385 	}
386 
387 	EFX_POPULATE_OWORD_10(*tx_desc,
388 			ESF_GZ_TX_SEND_ADDR, rte_mbuf_data_iova(m),
389 			ESF_GZ_TX_SEND_LEN, rte_pktmbuf_data_len(m),
390 			ESF_GZ_TX_SEND_NUM_SEGS, m->nb_segs,
391 			ESF_GZ_TX_SEND_CSO_PARTIAL_START_W, l4_offset_w,
392 			ESF_GZ_TX_SEND_CSO_PARTIAL_CSUM_W, part_cksum_w,
393 			ESF_GZ_TX_SEND_CSO_PARTIAL_EN, partial_en,
394 			ESF_GZ_TX_SEND_CSO_INNER_L3, inner_l3,
395 			ESF_GZ_TX_SEND_CSO_OUTER_L3, outer_l3,
396 			ESF_GZ_TX_SEND_CSO_OUTER_L4, outer_l4,
397 			ESF_GZ_TX_DESC_TYPE, ESE_GZ_TX_DESC_TYPE_SEND);
398 
399 	if (m->ol_flags & PKT_TX_VLAN_PKT) {
400 		efx_oword_t tx_desc_extra_fields;
401 
402 		EFX_POPULATE_OWORD_2(tx_desc_extra_fields,
403 				ESF_GZ_TX_SEND_VLAN_INSERT_EN, 1,
404 				ESF_GZ_TX_SEND_VLAN_INSERT_TCI, m->vlan_tci);
405 
406 		EFX_OR_OWORD(*tx_desc, tx_desc_extra_fields);
407 	}
408 }
409 
410 static void
411 sfc_ef100_tx_qdesc_seg_create(rte_iova_t addr, uint16_t len,
412 			      efx_oword_t *tx_desc)
413 {
414 	EFX_POPULATE_OWORD_3(*tx_desc,
415 			ESF_GZ_TX_SEG_ADDR, addr,
416 			ESF_GZ_TX_SEG_LEN, len,
417 			ESF_GZ_TX_DESC_TYPE, ESE_GZ_TX_DESC_TYPE_SEG);
418 }
419 
420 static void
421 sfc_ef100_tx_qdesc_tso_create(const struct rte_mbuf *m,
422 			      uint16_t nb_header_descs,
423 			      uint16_t nb_payload_descs,
424 			      size_t header_len, size_t payload_len,
425 			      size_t outer_iph_off, size_t outer_udph_off,
426 			      size_t iph_off, size_t tcph_off,
427 			      efx_oword_t *tx_desc)
428 {
429 	efx_oword_t tx_desc_extra_fields;
430 	int ed_outer_udp_len = (outer_udph_off != 0) ? 1 : 0;
431 	int ed_outer_ip_len = (outer_iph_off != 0) ? 1 : 0;
432 	int ed_outer_ip_id = (outer_iph_off != 0) ?
433 		ESE_GZ_TX_DESC_IP4_ID_INC_MOD16 : 0;
434 	/*
435 	 * If no tunnel encapsulation is present, then the ED_INNER
436 	 * fields should be used.
437 	 */
438 	int ed_inner_ip_id = ESE_GZ_TX_DESC_IP4_ID_INC_MOD16;
439 	uint8_t inner_l3 = sfc_ef100_tx_qdesc_cso_inner_l3(
440 					m->ol_flags & PKT_TX_TUNNEL_MASK);
441 
442 	EFX_POPULATE_OWORD_10(*tx_desc,
443 			ESF_GZ_TX_TSO_MSS, m->tso_segsz,
444 			ESF_GZ_TX_TSO_HDR_NUM_SEGS, nb_header_descs,
445 			ESF_GZ_TX_TSO_PAYLOAD_NUM_SEGS, nb_payload_descs,
446 			ESF_GZ_TX_TSO_ED_OUTER_IP4_ID, ed_outer_ip_id,
447 			ESF_GZ_TX_TSO_ED_INNER_IP4_ID, ed_inner_ip_id,
448 			ESF_GZ_TX_TSO_ED_OUTER_IP_LEN, ed_outer_ip_len,
449 			ESF_GZ_TX_TSO_ED_INNER_IP_LEN, 1,
450 			ESF_GZ_TX_TSO_ED_OUTER_UDP_LEN, ed_outer_udp_len,
451 			ESF_GZ_TX_TSO_HDR_LEN_W, header_len >> 1,
452 			ESF_GZ_TX_TSO_PAYLOAD_LEN, payload_len);
453 
454 	EFX_POPULATE_OWORD_9(tx_desc_extra_fields,
455 			/*
456 			 * Outer offsets are required for outer IPv4 ID
457 			 * and length edits in the case of tunnel TSO.
458 			 */
459 			ESF_GZ_TX_TSO_OUTER_L3_OFF_W, outer_iph_off >> 1,
460 			ESF_GZ_TX_TSO_OUTER_L4_OFF_W, outer_udph_off >> 1,
461 			/*
462 			 * Inner offsets are required for inner IPv4 ID
463 			 * and IP length edits and partial checksum
464 			 * offload in the case of tunnel TSO.
465 			 */
466 			ESF_GZ_TX_TSO_INNER_L3_OFF_W, iph_off >> 1,
467 			ESF_GZ_TX_TSO_INNER_L4_OFF_W, tcph_off >> 1,
468 			ESF_GZ_TX_TSO_CSO_INNER_L4,
469 				inner_l3 != ESE_GZ_TX_DESC_CS_INNER_L3_OFF,
470 			ESF_GZ_TX_TSO_CSO_INNER_L3, inner_l3,
471 			/*
472 			 * Use outer full checksum offloads which do
473 			 * not require any extra information.
474 			 */
475 			ESF_GZ_TX_TSO_CSO_OUTER_L3, 1,
476 			ESF_GZ_TX_TSO_CSO_OUTER_L4, 1,
477 			ESF_GZ_TX_DESC_TYPE, ESE_GZ_TX_DESC_TYPE_TSO);
478 
479 	EFX_OR_OWORD(*tx_desc, tx_desc_extra_fields);
480 
481 	if (m->ol_flags & PKT_TX_VLAN_PKT) {
482 		EFX_POPULATE_OWORD_2(tx_desc_extra_fields,
483 				ESF_GZ_TX_TSO_VLAN_INSERT_EN, 1,
484 				ESF_GZ_TX_TSO_VLAN_INSERT_TCI, m->vlan_tci);
485 
486 		EFX_OR_OWORD(*tx_desc, tx_desc_extra_fields);
487 	}
488 }
489 
490 static inline void
491 sfc_ef100_tx_qpush(struct sfc_ef100_txq *txq, unsigned int added)
492 {
493 	efx_dword_t dword;
494 
495 	EFX_POPULATE_DWORD_1(dword, ERF_GZ_TX_RING_PIDX, added & txq->ptr_mask);
496 
497 	/* DMA sync to device is not required */
498 
499 	/*
500 	 * rte_write32() has rte_io_wmb() which guarantees that the STORE
501 	 * operations (i.e. Rx and event descriptor updates) that precede
502 	 * the rte_io_wmb() call are visible to NIC before the STORE
503 	 * operations that follow it (i.e. doorbell write).
504 	 */
505 	rte_write32(dword.ed_u32[0], txq->doorbell);
506 	txq->dp.dpq.tx_dbells++;
507 
508 	sfc_ef100_tx_debug(txq, "TxQ pushed doorbell at pidx %u (added=%u)",
509 			   EFX_DWORD_FIELD(dword, ERF_GZ_TX_RING_PIDX),
510 			   added);
511 }
512 
513 static unsigned int
514 sfc_ef100_tx_pkt_descs_max(const struct rte_mbuf *m)
515 {
516 	unsigned int extra_descs = 0;
517 
518 /** Maximum length of an mbuf segment data */
519 #define SFC_MBUF_SEG_LEN_MAX		UINT16_MAX
520 	RTE_BUILD_BUG_ON(sizeof(m->data_len) != 2);
521 
522 	if (m->ol_flags & PKT_TX_TCP_SEG) {
523 		/* Tx TSO descriptor */
524 		extra_descs++;
525 		/*
526 		 * Extra Tx segment descriptor may be required if header
527 		 * ends in the middle of segment.
528 		 */
529 		extra_descs++;
530 	} else {
531 		/*
532 		 * mbuf segment cannot be bigger than maximum segment length
533 		 * and maximum packet length since TSO is not supported yet.
534 		 * Make sure that the first segment does not need fragmentation
535 		 * (split into many Tx descriptors).
536 		 */
537 		RTE_BUILD_BUG_ON(SFC_EF100_TX_SEND_DESC_LEN_MAX <
538 				 RTE_MIN((unsigned int)EFX_MAC_PDU_MAX,
539 				 SFC_MBUF_SEG_LEN_MAX));
540 	}
541 
542 	if (m->ol_flags & sfc_dp_mport_override) {
543 		/* Tx override prefix descriptor will be used */
544 		extra_descs++;
545 	}
546 
547 	/*
548 	 * Any segment of scattered packet cannot be bigger than maximum
549 	 * segment length. Make sure that subsequent segments do not need
550 	 * fragmentation (split into many Tx descriptors).
551 	 */
552 	RTE_BUILD_BUG_ON(SFC_EF100_TX_SEG_DESC_LEN_MAX < SFC_MBUF_SEG_LEN_MAX);
553 
554 	return m->nb_segs + extra_descs;
555 }
556 
557 static struct rte_mbuf *
558 sfc_ef100_xmit_tso_pkt(struct sfc_ef100_txq * const txq,
559 		       struct rte_mbuf *m, unsigned int *added)
560 {
561 	struct rte_mbuf *m_seg = m;
562 	unsigned int nb_hdr_descs;
563 	unsigned int nb_pld_descs;
564 	unsigned int seg_split = 0;
565 	unsigned int tso_desc_id;
566 	unsigned int id;
567 	size_t outer_iph_off;
568 	size_t outer_udph_off;
569 	size_t iph_off;
570 	size_t tcph_off;
571 	size_t header_len;
572 	size_t remaining_hdr_len;
573 
574 	if (m->ol_flags & PKT_TX_TUNNEL_MASK) {
575 		outer_iph_off = m->outer_l2_len;
576 		outer_udph_off = outer_iph_off + m->outer_l3_len;
577 	} else {
578 		outer_iph_off = 0;
579 		outer_udph_off = 0;
580 	}
581 	iph_off = outer_udph_off + m->l2_len;
582 	tcph_off = iph_off + m->l3_len;
583 	header_len = tcph_off + m->l4_len;
584 
585 	/*
586 	 * Remember ID of the TX_TSO descriptor to be filled in.
587 	 * We can't fill it in right now since we need to calculate
588 	 * number of header and payload segments first and don't want
589 	 * to traverse it twice here.
590 	 */
591 	tso_desc_id = (*added)++ & txq->ptr_mask;
592 
593 	remaining_hdr_len = header_len;
594 	do {
595 		id = (*added)++ & txq->ptr_mask;
596 		if (rte_pktmbuf_data_len(m_seg) <= remaining_hdr_len) {
597 			/* The segment is fully header segment */
598 			sfc_ef100_tx_qdesc_seg_create(
599 				rte_mbuf_data_iova(m_seg),
600 				rte_pktmbuf_data_len(m_seg),
601 				&txq->txq_hw_ring[id]);
602 			remaining_hdr_len -= rte_pktmbuf_data_len(m_seg);
603 		} else {
604 			/*
605 			 * The segment must be split into header and
606 			 * payload segments
607 			 */
608 			sfc_ef100_tx_qdesc_seg_create(
609 				rte_mbuf_data_iova(m_seg),
610 				remaining_hdr_len,
611 				&txq->txq_hw_ring[id]);
612 			SFC_ASSERT(txq->sw_ring[id].mbuf == NULL);
613 
614 			id = (*added)++ & txq->ptr_mask;
615 			sfc_ef100_tx_qdesc_seg_create(
616 				rte_mbuf_data_iova(m_seg) + remaining_hdr_len,
617 				rte_pktmbuf_data_len(m_seg) - remaining_hdr_len,
618 				&txq->txq_hw_ring[id]);
619 			remaining_hdr_len = 0;
620 			seg_split = 1;
621 		}
622 		txq->sw_ring[id].mbuf = m_seg;
623 		m_seg = m_seg->next;
624 	} while (remaining_hdr_len > 0);
625 
626 	/*
627 	 * If a segment is split into header and payload segments, added
628 	 * pointer counts it twice and we should correct it.
629 	 */
630 	nb_hdr_descs = ((id - tso_desc_id) & txq->ptr_mask) - seg_split;
631 	nb_pld_descs = m->nb_segs - nb_hdr_descs + seg_split;
632 
633 	sfc_ef100_tx_qdesc_tso_create(m, nb_hdr_descs, nb_pld_descs, header_len,
634 				      rte_pktmbuf_pkt_len(m) - header_len,
635 				      outer_iph_off, outer_udph_off,
636 				      iph_off, tcph_off,
637 				      &txq->txq_hw_ring[tso_desc_id]);
638 
639 	return m_seg;
640 }
641 
642 static uint16_t
643 sfc_ef100_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
644 {
645 	struct sfc_ef100_txq * const txq = sfc_ef100_txq_by_dp_txq(tx_queue);
646 	unsigned int added;
647 	unsigned int dma_desc_space;
648 	bool reap_done;
649 	struct rte_mbuf **pktp;
650 	struct rte_mbuf **pktp_end;
651 
652 	if (unlikely(txq->flags &
653 		     (SFC_EF100_TXQ_NOT_RUNNING | SFC_EF100_TXQ_EXCEPTION)))
654 		return 0;
655 
656 	added = txq->added;
657 	dma_desc_space = txq->max_fill_level - (added - txq->completed);
658 
659 	reap_done = (dma_desc_space < txq->free_thresh);
660 	if (reap_done) {
661 		sfc_ef100_tx_reap(txq);
662 		dma_desc_space = txq->max_fill_level - (added - txq->completed);
663 	}
664 
665 	for (pktp = &tx_pkts[0], pktp_end = &tx_pkts[nb_pkts];
666 	     pktp != pktp_end;
667 	     ++pktp) {
668 		struct rte_mbuf *m_seg = *pktp;
669 		unsigned int pkt_start = added;
670 		unsigned int id;
671 
672 		if (likely(pktp + 1 != pktp_end))
673 			rte_mbuf_prefetch_part1(pktp[1]);
674 
675 		if (sfc_ef100_tx_pkt_descs_max(m_seg) > dma_desc_space) {
676 			if (reap_done)
677 				break;
678 
679 			/* Push already prepared descriptors before polling */
680 			if (added != txq->added) {
681 				sfc_ef100_tx_qpush(txq, added);
682 				txq->added = added;
683 			}
684 
685 			sfc_ef100_tx_reap(txq);
686 			reap_done = true;
687 			dma_desc_space = txq->max_fill_level -
688 				(added - txq->completed);
689 			if (sfc_ef100_tx_pkt_descs_max(m_seg) > dma_desc_space)
690 				break;
691 		}
692 
693 		if (m_seg->ol_flags & sfc_dp_mport_override) {
694 			id = added++ & txq->ptr_mask;
695 			sfc_ef100_tx_qdesc_prefix_create(m_seg,
696 							 &txq->txq_hw_ring[id]);
697 		}
698 
699 		if (m_seg->ol_flags & PKT_TX_TCP_SEG) {
700 			m_seg = sfc_ef100_xmit_tso_pkt(txq, m_seg, &added);
701 		} else {
702 			id = added++ & txq->ptr_mask;
703 			sfc_ef100_tx_qdesc_send_create(m_seg,
704 						       &txq->txq_hw_ring[id]);
705 
706 			/*
707 			 * rte_pktmbuf_free() is commonly used in DPDK for
708 			 * recycling packets - the function checks every
709 			 * segment's reference counter and returns the
710 			 * buffer to its pool whenever possible;
711 			 * nevertheless, freeing mbuf segments one by one
712 			 * may entail some performance decline;
713 			 * from this point, sfc_efx_tx_reap() does the same job
714 			 * on its own and frees buffers in bulks (all mbufs
715 			 * within a bulk belong to the same pool);
716 			 * from this perspective, individual segment pointers
717 			 * must be associated with the corresponding SW
718 			 * descriptors independently so that only one loop
719 			 * is sufficient on reap to inspect all the buffers
720 			 */
721 			txq->sw_ring[id].mbuf = m_seg;
722 			m_seg = m_seg->next;
723 		}
724 
725 		while (m_seg != NULL) {
726 			RTE_BUILD_BUG_ON(SFC_MBUF_SEG_LEN_MAX >
727 					 SFC_EF100_TX_SEG_DESC_LEN_MAX);
728 
729 			id = added++ & txq->ptr_mask;
730 			sfc_ef100_tx_qdesc_seg_create(rte_mbuf_data_iova(m_seg),
731 					rte_pktmbuf_data_len(m_seg),
732 					&txq->txq_hw_ring[id]);
733 			txq->sw_ring[id].mbuf = m_seg;
734 			m_seg = m_seg->next;
735 		}
736 
737 		dma_desc_space -= (added - pkt_start);
738 
739 		sfc_pkts_bytes_add(&txq->dp.dpq.stats, 1,
740 				   rte_pktmbuf_pkt_len(*pktp));
741 	}
742 
743 	if (likely(added != txq->added)) {
744 		sfc_ef100_tx_qpush(txq, added);
745 		txq->added = added;
746 	}
747 
748 #if SFC_TX_XMIT_PKTS_REAP_AT_LEAST_ONCE
749 	if (!reap_done)
750 		sfc_ef100_tx_reap(txq);
751 #endif
752 
753 	return pktp - &tx_pkts[0];
754 }
755 
756 static sfc_dp_tx_get_dev_info_t sfc_ef100_get_dev_info;
757 static void
758 sfc_ef100_get_dev_info(struct rte_eth_dev_info *dev_info)
759 {
760 	/*
761 	 * Number of descriptors just defines maximum number of pushed
762 	 * descriptors (fill level).
763 	 */
764 	dev_info->tx_desc_lim.nb_min = 1;
765 	dev_info->tx_desc_lim.nb_align = 1;
766 }
767 
768 static sfc_dp_tx_qsize_up_rings_t sfc_ef100_tx_qsize_up_rings;
769 static int
770 sfc_ef100_tx_qsize_up_rings(uint16_t nb_tx_desc,
771 			   struct sfc_dp_tx_hw_limits *limits,
772 			   unsigned int *txq_entries,
773 			   unsigned int *evq_entries,
774 			   unsigned int *txq_max_fill_level)
775 {
776 	/*
777 	 * rte_ethdev API guarantees that the number meets min, max and
778 	 * alignment requirements.
779 	 */
780 	if (nb_tx_desc <= limits->txq_min_entries)
781 		*txq_entries = limits->txq_min_entries;
782 	else
783 		*txq_entries = rte_align32pow2(nb_tx_desc);
784 
785 	*evq_entries = *txq_entries;
786 
787 	*txq_max_fill_level = RTE_MIN(nb_tx_desc,
788 				      SFC_EF100_TXQ_LIMIT(*evq_entries));
789 	return 0;
790 }
791 
792 static sfc_dp_tx_qcreate_t sfc_ef100_tx_qcreate;
793 static int
794 sfc_ef100_tx_qcreate(uint16_t port_id, uint16_t queue_id,
795 		    const struct rte_pci_addr *pci_addr, int socket_id,
796 		    const struct sfc_dp_tx_qcreate_info *info,
797 		    struct sfc_dp_txq **dp_txqp)
798 {
799 	struct sfc_ef100_txq *txq;
800 	int rc;
801 
802 	rc = EINVAL;
803 	if (info->txq_entries != info->evq_entries)
804 		goto fail_bad_args;
805 
806 	rc = ENOMEM;
807 	txq = rte_zmalloc_socket("sfc-ef100-txq", sizeof(*txq),
808 				 RTE_CACHE_LINE_SIZE, socket_id);
809 	if (txq == NULL)
810 		goto fail_txq_alloc;
811 
812 	sfc_dp_queue_init(&txq->dp.dpq, port_id, queue_id, pci_addr);
813 
814 	rc = ENOMEM;
815 	txq->sw_ring = rte_calloc_socket("sfc-ef100-txq-sw_ring",
816 					 info->txq_entries,
817 					 sizeof(*txq->sw_ring),
818 					 RTE_CACHE_LINE_SIZE, socket_id);
819 	if (txq->sw_ring == NULL)
820 		goto fail_sw_ring_alloc;
821 
822 	txq->flags = SFC_EF100_TXQ_NOT_RUNNING;
823 	txq->ptr_mask = info->txq_entries - 1;
824 	txq->max_fill_level = info->max_fill_level;
825 	txq->free_thresh = info->free_thresh;
826 	txq->evq_phase_bit_shift = rte_bsf32(info->evq_entries);
827 	txq->txq_hw_ring = info->txq_hw_ring;
828 	txq->doorbell = (volatile uint8_t *)info->mem_bar +
829 			ER_GZ_TX_RING_DOORBELL_OFST +
830 			(info->hw_index << info->vi_window_shift);
831 	txq->evq_hw_ring = info->evq_hw_ring;
832 
833 	txq->tso_tcp_header_offset_limit = info->tso_tcp_header_offset_limit;
834 	txq->tso_max_nb_header_descs = info->tso_max_nb_header_descs;
835 	txq->tso_max_header_len = info->tso_max_header_len;
836 	txq->tso_max_nb_payload_descs = info->tso_max_nb_payload_descs;
837 	txq->tso_max_payload_len = info->tso_max_payload_len;
838 	txq->tso_max_nb_outgoing_frames = info->tso_max_nb_outgoing_frames;
839 
840 	sfc_ef100_tx_debug(txq, "TxQ doorbell is %p", txq->doorbell);
841 
842 	*dp_txqp = &txq->dp;
843 	return 0;
844 
845 fail_sw_ring_alloc:
846 	rte_free(txq);
847 
848 fail_txq_alloc:
849 fail_bad_args:
850 	return rc;
851 }
852 
853 static sfc_dp_tx_qdestroy_t sfc_ef100_tx_qdestroy;
854 static void
855 sfc_ef100_tx_qdestroy(struct sfc_dp_txq *dp_txq)
856 {
857 	struct sfc_ef100_txq *txq = sfc_ef100_txq_by_dp_txq(dp_txq);
858 
859 	rte_free(txq->sw_ring);
860 	rte_free(txq);
861 }
862 
863 static sfc_dp_tx_qstart_t sfc_ef100_tx_qstart;
864 static int
865 sfc_ef100_tx_qstart(struct sfc_dp_txq *dp_txq, unsigned int evq_read_ptr,
866 		   unsigned int txq_desc_index)
867 {
868 	struct sfc_ef100_txq *txq = sfc_ef100_txq_by_dp_txq(dp_txq);
869 
870 	txq->evq_read_ptr = evq_read_ptr;
871 	txq->added = txq->completed = txq_desc_index;
872 
873 	txq->flags |= SFC_EF100_TXQ_STARTED;
874 	txq->flags &= ~(SFC_EF100_TXQ_NOT_RUNNING | SFC_EF100_TXQ_EXCEPTION);
875 
876 	return 0;
877 }
878 
879 static sfc_dp_tx_qstop_t sfc_ef100_tx_qstop;
880 static void
881 sfc_ef100_tx_qstop(struct sfc_dp_txq *dp_txq, unsigned int *evq_read_ptr)
882 {
883 	struct sfc_ef100_txq *txq = sfc_ef100_txq_by_dp_txq(dp_txq);
884 
885 	txq->flags |= SFC_EF100_TXQ_NOT_RUNNING;
886 
887 	*evq_read_ptr = txq->evq_read_ptr;
888 }
889 
890 static sfc_dp_tx_qtx_ev_t sfc_ef100_tx_qtx_ev;
891 static bool
892 sfc_ef100_tx_qtx_ev(struct sfc_dp_txq *dp_txq, unsigned int num_descs)
893 {
894 	struct sfc_ef100_txq *txq = sfc_ef100_txq_by_dp_txq(dp_txq);
895 
896 	SFC_ASSERT(txq->flags & SFC_EF100_TXQ_NOT_RUNNING);
897 
898 	sfc_ef100_tx_reap_num_descs(txq, num_descs);
899 
900 	return false;
901 }
902 
903 static sfc_dp_tx_qreap_t sfc_ef100_tx_qreap;
904 static void
905 sfc_ef100_tx_qreap(struct sfc_dp_txq *dp_txq)
906 {
907 	struct sfc_ef100_txq *txq = sfc_ef100_txq_by_dp_txq(dp_txq);
908 	unsigned int completed;
909 
910 	for (completed = txq->completed; completed != txq->added; ++completed) {
911 		struct sfc_ef100_tx_sw_desc *txd;
912 
913 		txd = &txq->sw_ring[completed & txq->ptr_mask];
914 		if (txd->mbuf != NULL) {
915 			rte_pktmbuf_free_seg(txd->mbuf);
916 			txd->mbuf = NULL;
917 		}
918 	}
919 
920 	txq->flags &= ~SFC_EF100_TXQ_STARTED;
921 }
922 
923 static unsigned int
924 sfc_ef100_tx_qdesc_npending(struct sfc_ef100_txq *txq)
925 {
926 	const unsigned int evq_old_read_ptr = txq->evq_read_ptr;
927 	unsigned int npending = 0;
928 	efx_qword_t tx_ev;
929 
930 	if (unlikely(txq->flags &
931 		     (SFC_EF100_TXQ_NOT_RUNNING | SFC_EF100_TXQ_EXCEPTION)))
932 		return 0;
933 
934 	while (sfc_ef100_tx_get_event(txq, &tx_ev))
935 		npending += EFX_QWORD_FIELD(tx_ev, ESF_GZ_EV_TXCMPL_NUM_DESC);
936 
937 	/*
938 	 * The function does not process events, so return event queue read
939 	 * pointer to the original position to allow the events that were
940 	 * read to be processed later
941 	 */
942 	txq->evq_read_ptr = evq_old_read_ptr;
943 
944 	return npending;
945 }
946 
947 static sfc_dp_tx_qdesc_status_t sfc_ef100_tx_qdesc_status;
948 static int
949 sfc_ef100_tx_qdesc_status(struct sfc_dp_txq *dp_txq, uint16_t offset)
950 {
951 	struct sfc_ef100_txq *txq = sfc_ef100_txq_by_dp_txq(dp_txq);
952 	unsigned int pushed = txq->added - txq->completed;
953 
954 	if (unlikely(offset > txq->ptr_mask))
955 		return -EINVAL;
956 
957 	if (unlikely(offset >= txq->max_fill_level))
958 		return RTE_ETH_TX_DESC_UNAVAIL;
959 
960 	return (offset >= pushed ||
961 		offset < sfc_ef100_tx_qdesc_npending(txq)) ?
962 		RTE_ETH_TX_DESC_DONE : RTE_ETH_TX_DESC_FULL;
963 }
964 
965 struct sfc_dp_tx sfc_ef100_tx = {
966 	.dp = {
967 		.name		= SFC_KVARG_DATAPATH_EF100,
968 		.type		= SFC_DP_TX,
969 		.hw_fw_caps	= SFC_DP_HW_FW_CAP_EF100,
970 	},
971 	.features		= SFC_DP_TX_FEAT_MULTI_PROCESS |
972 				  SFC_DP_TX_FEAT_STATS,
973 	.dev_offload_capa	= 0,
974 	.queue_offload_capa	= DEV_TX_OFFLOAD_VLAN_INSERT |
975 				  DEV_TX_OFFLOAD_IPV4_CKSUM |
976 				  DEV_TX_OFFLOAD_OUTER_IPV4_CKSUM |
977 				  DEV_TX_OFFLOAD_OUTER_UDP_CKSUM |
978 				  DEV_TX_OFFLOAD_UDP_CKSUM |
979 				  DEV_TX_OFFLOAD_TCP_CKSUM |
980 				  DEV_TX_OFFLOAD_MULTI_SEGS |
981 				  DEV_TX_OFFLOAD_TCP_TSO |
982 				  DEV_TX_OFFLOAD_VXLAN_TNL_TSO |
983 				  DEV_TX_OFFLOAD_GENEVE_TNL_TSO,
984 	.get_dev_info		= sfc_ef100_get_dev_info,
985 	.qsize_up_rings		= sfc_ef100_tx_qsize_up_rings,
986 	.qcreate		= sfc_ef100_tx_qcreate,
987 	.qdestroy		= sfc_ef100_tx_qdestroy,
988 	.qstart			= sfc_ef100_tx_qstart,
989 	.qtx_ev			= sfc_ef100_tx_qtx_ev,
990 	.qstop			= sfc_ef100_tx_qstop,
991 	.qreap			= sfc_ef100_tx_qreap,
992 	.qdesc_status		= sfc_ef100_tx_qdesc_status,
993 	.pkt_prepare		= sfc_ef100_tx_prepare_pkts,
994 	.pkt_burst		= sfc_ef100_xmit_pkts,
995 };
996