xref: /freebsd/sys/dev/cxgbe/t4_netmap.c (revision a9f47658)
1 /*-
2  * Copyright (c) 2014 Chelsio Communications, Inc.
3  * All rights reserved.
4  * Written by: Navdeep Parhar <np@FreeBSD.org>
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 
31 #include "opt_inet.h"
32 #include "opt_inet6.h"
33 
34 #ifdef DEV_NETMAP
35 #include <sys/param.h>
36 #include <sys/bus.h>
37 #include <sys/eventhandler.h>
38 #include <sys/lock.h>
39 #include <sys/mbuf.h>
40 #include <sys/module.h>
41 #include <sys/selinfo.h>
42 #include <sys/socket.h>
43 #include <sys/sockio.h>
44 #include <machine/bus.h>
45 #include <net/ethernet.h>
46 #include <net/if.h>
47 #include <net/if_media.h>
48 #include <net/if_var.h>
49 #include <net/if_clone.h>
50 #include <net/if_types.h>
51 #include <net/netmap.h>
52 #include <dev/netmap/netmap_kern.h>
53 
54 #include "common/common.h"
55 #include "common/t4_regs.h"
56 #include "common/t4_regs_values.h"
57 
58 extern int fl_pad;	/* XXXNM */
59 
60 /*
61  * 0 = normal netmap rx
62  * 1 = black hole
63  * 2 = supermassive black hole (buffer packing enabled)
64  */
65 int black_hole = 0;
66 SYSCTL_INT(_hw_cxgbe, OID_AUTO, nm_black_hole, CTLFLAG_RWTUN, &black_hole, 0,
67     "Sink incoming packets.");
68 
69 int rx_ndesc = 256;
70 SYSCTL_INT(_hw_cxgbe, OID_AUTO, nm_rx_ndesc, CTLFLAG_RWTUN,
71     &rx_ndesc, 0, "# of rx descriptors after which the hw cidx is updated.");
72 
73 int rx_nframes = 64;
74 SYSCTL_INT(_hw_cxgbe, OID_AUTO, nm_rx_nframes, CTLFLAG_RWTUN,
75     &rx_nframes, 0, "max # of frames received before waking up netmap rx.");
76 
77 int holdoff_tmr_idx = 2;
78 SYSCTL_INT(_hw_cxgbe, OID_AUTO, nm_holdoff_tmr_idx, CTLFLAG_RWTUN,
79     &holdoff_tmr_idx, 0, "Holdoff timer index for netmap rx queues.");
80 
81 /*
82  * Congestion drops.
83  * -1: no congestion feedback (not recommended).
84  *  0: backpressure the channel instead of dropping packets right away.
85  *  1: no backpressure, drop packets for the congested queue immediately.
86  */
87 static int nm_cong_drop = 1;
88 SYSCTL_INT(_hw_cxgbe, OID_AUTO, nm_cong_drop, CTLFLAG_RWTUN,
89     &nm_cong_drop, 0,
90     "Congestion control for netmap rx queues (0 = backpressure, 1 = drop");
91 
92 int starve_fl = 0;
93 SYSCTL_INT(_hw_cxgbe, OID_AUTO, starve_fl, CTLFLAG_RWTUN,
94     &starve_fl, 0, "Don't ring fl db for netmap rx queues.");
95 
96 /*
97  * Try to process tx credits in bulk.  This may cause a delay in the return of
98  * tx credits and is suitable for bursty or non-stop tx only.
99  */
100 int lazy_tx_credit_flush = 1;
101 SYSCTL_INT(_hw_cxgbe, OID_AUTO, lazy_tx_credit_flush, CTLFLAG_RWTUN,
102     &lazy_tx_credit_flush, 0, "lazy credit flush for netmap tx queues.");
103 
104 /*
105  * Split the netmap rx queues into two groups that populate separate halves of
106  * the RSS indirection table.  This allows filters with hashmask to steer to a
107  * particular group of queues.
108  */
109 static int nm_split_rss = 0;
110 SYSCTL_INT(_hw_cxgbe, OID_AUTO, nm_split_rss, CTLFLAG_RWTUN,
111     &nm_split_rss, 0, "Split the netmap rx queues into two groups.");
112 
113 /*
114  * netmap(4) says "netmap does not use features such as checksum offloading, TCP
115  * segmentation offloading, encryption, VLAN encapsulation/decapsulation, etc."
116  * but this knob can be used to get the hardware to checksum all tx traffic
117  * anyway.
118  */
119 static int nm_txcsum = 0;
120 SYSCTL_INT(_hw_cxgbe, OID_AUTO, nm_txcsum, CTLFLAG_RWTUN,
121     &nm_txcsum, 0, "Enable transmit checksum offloading.");
122 
123 static int
124 alloc_nm_rxq_hwq(struct vi_info *vi, struct sge_nm_rxq *nm_rxq, int cong)
125 {
126 	int rc, cntxt_id, i;
127 	__be32 v;
128 	struct adapter *sc = vi->adapter;
129 	struct sge_params *sp = &sc->params.sge;
130 	struct netmap_adapter *na = NA(vi->ifp);
131 	struct fw_iq_cmd c;
132 
133 	MPASS(na != NULL);
134 	MPASS(nm_rxq->iq_desc != NULL);
135 	MPASS(nm_rxq->fl_desc != NULL);
136 
137 	bzero(nm_rxq->iq_desc, vi->qsize_rxq * IQ_ESIZE);
138 	bzero(nm_rxq->fl_desc, na->num_rx_desc * EQ_ESIZE + sp->spg_len);
139 
140 	bzero(&c, sizeof(c));
141 	c.op_to_vfn = htobe32(V_FW_CMD_OP(FW_IQ_CMD) | F_FW_CMD_REQUEST |
142 	    F_FW_CMD_WRITE | F_FW_CMD_EXEC | V_FW_IQ_CMD_PFN(sc->pf) |
143 	    V_FW_IQ_CMD_VFN(0));
144 	c.alloc_to_len16 = htobe32(F_FW_IQ_CMD_ALLOC | F_FW_IQ_CMD_IQSTART |
145 	    FW_LEN16(c));
146 	MPASS(!forwarding_intr_to_fwq(sc));
147 	KASSERT(nm_rxq->intr_idx < sc->intr_count,
148 	    ("%s: invalid direct intr_idx %d", __func__, nm_rxq->intr_idx));
149 	v = V_FW_IQ_CMD_IQANDSTINDEX(nm_rxq->intr_idx);
150 	c.type_to_iqandstindex = htobe32(v |
151 	    V_FW_IQ_CMD_TYPE(FW_IQ_TYPE_FL_INT_CAP) |
152 	    V_FW_IQ_CMD_VIID(vi->viid) |
153 	    V_FW_IQ_CMD_IQANUD(X_UPDATEDELIVERY_INTERRUPT));
154 	c.iqdroprss_to_iqesize = htobe16(V_FW_IQ_CMD_IQPCIECH(vi->pi->tx_chan) |
155 	    F_FW_IQ_CMD_IQGTSMODE |
156 	    V_FW_IQ_CMD_IQINTCNTTHRESH(0) |
157 	    V_FW_IQ_CMD_IQESIZE(ilog2(IQ_ESIZE) - 4));
158 	c.iqsize = htobe16(vi->qsize_rxq);
159 	c.iqaddr = htobe64(nm_rxq->iq_ba);
160 	if (cong >= 0) {
161 		c.iqns_to_fl0congen = htobe32(F_FW_IQ_CMD_IQFLINTCONGEN |
162 		    V_FW_IQ_CMD_FL0CNGCHMAP(cong) | F_FW_IQ_CMD_FL0CONGCIF |
163 		    F_FW_IQ_CMD_FL0CONGEN);
164 	}
165 	c.iqns_to_fl0congen |=
166 	    htobe32(V_FW_IQ_CMD_FL0HOSTFCMODE(X_HOSTFCMODE_NONE) |
167 		F_FW_IQ_CMD_FL0FETCHRO | F_FW_IQ_CMD_FL0DATARO |
168 		(fl_pad ? F_FW_IQ_CMD_FL0PADEN : 0) |
169 		(black_hole == 2 ? F_FW_IQ_CMD_FL0PACKEN : 0));
170 	c.fl0dcaen_to_fl0cidxfthresh =
171 	    htobe16(V_FW_IQ_CMD_FL0FBMIN(chip_id(sc) <= CHELSIO_T5 ?
172 		X_FETCHBURSTMIN_128B : X_FETCHBURSTMIN_64B_T6) |
173 		V_FW_IQ_CMD_FL0FBMAX(chip_id(sc) <= CHELSIO_T5 ?
174 		X_FETCHBURSTMAX_512B : X_FETCHBURSTMAX_256B));
175 	c.fl0size = htobe16(na->num_rx_desc / 8 + sp->spg_len / EQ_ESIZE);
176 	c.fl0addr = htobe64(nm_rxq->fl_ba);
177 
178 	rc = -t4_wr_mbox(sc, sc->mbox, &c, sizeof(c), &c);
179 	if (rc != 0) {
180 		device_printf(sc->dev,
181 		    "failed to create netmap ingress queue: %d\n", rc);
182 		return (rc);
183 	}
184 
185 	nm_rxq->iq_cidx = 0;
186 	MPASS(nm_rxq->iq_sidx == vi->qsize_rxq - sp->spg_len / IQ_ESIZE);
187 	nm_rxq->iq_gen = F_RSPD_GEN;
188 	nm_rxq->iq_cntxt_id = be16toh(c.iqid);
189 	nm_rxq->iq_abs_id = be16toh(c.physiqid);
190 	cntxt_id = nm_rxq->iq_cntxt_id - sc->sge.iq_start;
191 	if (cntxt_id >= sc->sge.niq) {
192 		panic ("%s: nm_rxq->iq_cntxt_id (%d) more than the max (%d)",
193 		    __func__, cntxt_id, sc->sge.niq - 1);
194 	}
195 	sc->sge.iqmap[cntxt_id] = (void *)nm_rxq;
196 
197 	nm_rxq->fl_cntxt_id = be16toh(c.fl0id);
198 	nm_rxq->fl_pidx = nm_rxq->fl_cidx = 0;
199 	MPASS(nm_rxq->fl_sidx == na->num_rx_desc);
200 	cntxt_id = nm_rxq->fl_cntxt_id - sc->sge.eq_start;
201 	if (cntxt_id >= sc->sge.neq) {
202 		panic("%s: nm_rxq->fl_cntxt_id (%d) more than the max (%d)",
203 		    __func__, cntxt_id, sc->sge.neq - 1);
204 	}
205 	sc->sge.eqmap[cntxt_id] = (void *)nm_rxq;
206 
207 	nm_rxq->fl_db_val = V_QID(nm_rxq->fl_cntxt_id) |
208 	    sc->chip_params->sge_fl_db;
209 
210 	if (chip_id(sc) >= CHELSIO_T5 && cong >= 0) {
211 		uint32_t param, val;
212 
213 		param = V_FW_PARAMS_MNEM(FW_PARAMS_MNEM_DMAQ) |
214 		    V_FW_PARAMS_PARAM_X(FW_PARAMS_PARAM_DMAQ_CONM_CTXT) |
215 		    V_FW_PARAMS_PARAM_YZ(nm_rxq->iq_cntxt_id);
216 		param = V_FW_PARAMS_MNEM(FW_PARAMS_MNEM_DMAQ) |
217 		    V_FW_PARAMS_PARAM_X(FW_PARAMS_PARAM_DMAQ_CONM_CTXT) |
218 		    V_FW_PARAMS_PARAM_YZ(nm_rxq->iq_cntxt_id);
219 		if (cong == 0)
220 			val = 1 << 19;
221 		else {
222 			val = 2 << 19;
223 			for (i = 0; i < 4; i++) {
224 				if (cong & (1 << i))
225 					val |= 1 << (i << 2);
226 			}
227 		}
228 
229 		rc = -t4_set_params(sc, sc->mbox, sc->pf, 0, 1, &param, &val);
230 		if (rc != 0) {
231 			/* report error but carry on */
232 			device_printf(sc->dev,
233 			    "failed to set congestion manager context for "
234 			    "ingress queue %d: %d\n", nm_rxq->iq_cntxt_id, rc);
235 		}
236 	}
237 
238 	t4_write_reg(sc, sc->sge_gts_reg,
239 	    V_INGRESSQID(nm_rxq->iq_cntxt_id) |
240 	    V_SEINTARM(V_QINTR_TIMER_IDX(holdoff_tmr_idx)));
241 
242 	return (rc);
243 }
244 
245 static int
246 free_nm_rxq_hwq(struct vi_info *vi, struct sge_nm_rxq *nm_rxq)
247 {
248 	struct adapter *sc = vi->adapter;
249 	int rc;
250 
251 	rc = -t4_iq_free(sc, sc->mbox, sc->pf, 0, FW_IQ_TYPE_FL_INT_CAP,
252 	    nm_rxq->iq_cntxt_id, nm_rxq->fl_cntxt_id, 0xffff);
253 	if (rc != 0)
254 		device_printf(sc->dev, "%s: failed for iq %d, fl %d: %d\n",
255 		    __func__, nm_rxq->iq_cntxt_id, nm_rxq->fl_cntxt_id, rc);
256 	nm_rxq->iq_cntxt_id = INVALID_NM_RXQ_CNTXT_ID;
257 	return (rc);
258 }
259 
260 static int
261 alloc_nm_txq_hwq(struct vi_info *vi, struct sge_nm_txq *nm_txq)
262 {
263 	int rc, cntxt_id;
264 	size_t len;
265 	struct adapter *sc = vi->adapter;
266 	struct netmap_adapter *na = NA(vi->ifp);
267 	struct fw_eq_eth_cmd c;
268 
269 	MPASS(na != NULL);
270 	MPASS(nm_txq->desc != NULL);
271 
272 	len = na->num_tx_desc * EQ_ESIZE + sc->params.sge.spg_len;
273 	bzero(nm_txq->desc, len);
274 
275 	bzero(&c, sizeof(c));
276 	c.op_to_vfn = htobe32(V_FW_CMD_OP(FW_EQ_ETH_CMD) | F_FW_CMD_REQUEST |
277 	    F_FW_CMD_WRITE | F_FW_CMD_EXEC | V_FW_EQ_ETH_CMD_PFN(sc->pf) |
278 	    V_FW_EQ_ETH_CMD_VFN(0));
279 	c.alloc_to_len16 = htobe32(F_FW_EQ_ETH_CMD_ALLOC |
280 	    F_FW_EQ_ETH_CMD_EQSTART | FW_LEN16(c));
281 	c.autoequiqe_to_viid = htobe32(F_FW_EQ_ETH_CMD_AUTOEQUIQE |
282 	    F_FW_EQ_ETH_CMD_AUTOEQUEQE | V_FW_EQ_ETH_CMD_VIID(vi->viid));
283 	c.fetchszm_to_iqid =
284 	    htobe32(V_FW_EQ_ETH_CMD_HOSTFCMODE(X_HOSTFCMODE_NONE) |
285 		V_FW_EQ_ETH_CMD_PCIECHN(vi->pi->tx_chan) | F_FW_EQ_ETH_CMD_FETCHRO |
286 		V_FW_EQ_ETH_CMD_IQID(sc->sge.nm_rxq[nm_txq->iqidx].iq_cntxt_id));
287 	c.dcaen_to_eqsize =
288 	    htobe32(V_FW_EQ_ETH_CMD_FBMIN(chip_id(sc) <= CHELSIO_T5 ?
289 		X_FETCHBURSTMIN_64B : X_FETCHBURSTMIN_64B_T6) |
290 		V_FW_EQ_ETH_CMD_FBMAX(X_FETCHBURSTMAX_512B) |
291 		V_FW_EQ_ETH_CMD_EQSIZE(len / EQ_ESIZE));
292 	c.eqaddr = htobe64(nm_txq->ba);
293 
294 	rc = -t4_wr_mbox(sc, sc->mbox, &c, sizeof(c), &c);
295 	if (rc != 0) {
296 		device_printf(vi->dev,
297 		    "failed to create netmap egress queue: %d\n", rc);
298 		return (rc);
299 	}
300 
301 	nm_txq->cntxt_id = G_FW_EQ_ETH_CMD_EQID(be32toh(c.eqid_pkd));
302 	cntxt_id = nm_txq->cntxt_id - sc->sge.eq_start;
303 	if (cntxt_id >= sc->sge.neq)
304 	    panic("%s: nm_txq->cntxt_id (%d) more than the max (%d)", __func__,
305 		cntxt_id, sc->sge.neq - 1);
306 	sc->sge.eqmap[cntxt_id] = (void *)nm_txq;
307 
308 	nm_txq->pidx = nm_txq->cidx = 0;
309 	MPASS(nm_txq->sidx == na->num_tx_desc);
310 	nm_txq->equiqidx = nm_txq->equeqidx = nm_txq->dbidx = 0;
311 
312 	nm_txq->doorbells = sc->doorbells;
313 	if (isset(&nm_txq->doorbells, DOORBELL_UDB) ||
314 	    isset(&nm_txq->doorbells, DOORBELL_UDBWC) ||
315 	    isset(&nm_txq->doorbells, DOORBELL_WCWR)) {
316 		uint32_t s_qpp = sc->params.sge.eq_s_qpp;
317 		uint32_t mask = (1 << s_qpp) - 1;
318 		volatile uint8_t *udb;
319 
320 		udb = sc->udbs_base + UDBS_DB_OFFSET;
321 		udb += (nm_txq->cntxt_id >> s_qpp) << PAGE_SHIFT;
322 		nm_txq->udb_qid = nm_txq->cntxt_id & mask;
323 		if (nm_txq->udb_qid >= PAGE_SIZE / UDBS_SEG_SIZE)
324 	    		clrbit(&nm_txq->doorbells, DOORBELL_WCWR);
325 		else {
326 			udb += nm_txq->udb_qid << UDBS_SEG_SHIFT;
327 			nm_txq->udb_qid = 0;
328 		}
329 		nm_txq->udb = (volatile void *)udb;
330 	}
331 
332 	return (rc);
333 }
334 
335 static int
336 free_nm_txq_hwq(struct vi_info *vi, struct sge_nm_txq *nm_txq)
337 {
338 	struct adapter *sc = vi->adapter;
339 	int rc;
340 
341 	rc = -t4_eth_eq_free(sc, sc->mbox, sc->pf, 0, nm_txq->cntxt_id);
342 	if (rc != 0)
343 		device_printf(sc->dev, "%s: failed for eq %d: %d\n", __func__,
344 		    nm_txq->cntxt_id, rc);
345 	nm_txq->cntxt_id = INVALID_NM_TXQ_CNTXT_ID;
346 	return (rc);
347 }
348 
349 static int
350 cxgbe_netmap_simple_rss(struct adapter *sc, struct vi_info *vi,
351     struct ifnet *ifp, struct netmap_adapter *na)
352 {
353 	struct netmap_kring *kring;
354 	struct sge_nm_rxq *nm_rxq;
355 	int rc, i, j, nm_state, defq;
356 	uint16_t *rss;
357 
358 	/*
359 	 * Check if there's at least one active (or about to go active) netmap
360 	 * rx queue.
361 	 */
362 	defq = -1;
363 	for_each_nm_rxq(vi, j, nm_rxq) {
364 		nm_state = atomic_load_int(&nm_rxq->nm_state);
365 		kring = na->rx_rings[nm_rxq->nid];
366 		if ((nm_state != NM_OFF && !nm_kring_pending_off(kring)) ||
367 		    (nm_state == NM_OFF && nm_kring_pending_on(kring))) {
368 			MPASS(nm_rxq->iq_cntxt_id != INVALID_NM_RXQ_CNTXT_ID);
369 			if (defq == -1) {
370 				defq = nm_rxq->iq_abs_id;
371 				break;
372 			}
373 		}
374 	}
375 
376 	if (defq == -1) {
377 		/* No active netmap queues.  Switch back to NIC queues. */
378 		rss = vi->rss;
379 		defq = vi->rss[0];
380 	} else {
381 		for (i = 0; i < vi->rss_size;) {
382 			for_each_nm_rxq(vi, j, nm_rxq) {
383 				nm_state = atomic_load_int(&nm_rxq->nm_state);
384 				kring = na->rx_rings[nm_rxq->nid];
385 				if ((nm_state != NM_OFF &&
386 				    !nm_kring_pending_off(kring)) ||
387 				    (nm_state == NM_OFF &&
388 				    nm_kring_pending_on(kring))) {
389 					MPASS(nm_rxq->iq_cntxt_id !=
390 					    INVALID_NM_RXQ_CNTXT_ID);
391 					vi->nm_rss[i++] = nm_rxq->iq_abs_id;
392 					if (i == vi->rss_size)
393 						break;
394 				}
395 			}
396 		}
397 		rss = vi->nm_rss;
398 	}
399 
400 	rc = -t4_config_rss_range(sc, sc->mbox, vi->viid, 0, vi->rss_size, rss,
401 	    vi->rss_size);
402 	if (rc != 0)
403 		if_printf(ifp, "netmap rss_config failed: %d\n", rc);
404 
405 	rc = -t4_config_vi_rss(sc, sc->mbox, vi->viid, vi->hashen, defq, 0, 0);
406 	if (rc != 0) {
407 		if_printf(ifp, "netmap defaultq config failed: %d\n", rc);
408 	}
409 
410 	return (rc);
411 }
412 
413 /*
414  * Odd number of rx queues work best for split RSS mode as the first queue can
415  * be dedicated for non-RSS traffic and the rest divided into two equal halves.
416  */
417 static int
418 cxgbe_netmap_split_rss(struct adapter *sc, struct vi_info *vi,
419     struct ifnet *ifp, struct netmap_adapter *na)
420 {
421 	struct netmap_kring *kring;
422 	struct sge_nm_rxq *nm_rxq;
423 	int rc, i, j, nm_state, defq;
424 	int nactive[2] = {0, 0};
425 	int dq[2] = {-1, -1};
426 	bool dq_norss;		/* default queue should not be in RSS table. */
427 
428 	MPASS(nm_split_rss != 0);
429 	MPASS(vi->nnmrxq > 1);
430 
431 	for_each_nm_rxq(vi, i, nm_rxq) {
432 		j = i / ((vi->nnmrxq + 1) / 2);
433 		nm_state = atomic_load_int(&nm_rxq->nm_state);
434 		kring = na->rx_rings[nm_rxq->nid];
435 		if ((nm_state != NM_OFF && !nm_kring_pending_off(kring)) ||
436 		    (nm_state == NM_OFF && nm_kring_pending_on(kring))) {
437 			MPASS(nm_rxq->iq_cntxt_id != INVALID_NM_RXQ_CNTXT_ID);
438 			nactive[j]++;
439 			if (dq[j] == -1) {
440 				dq[j] = nm_rxq->iq_abs_id;
441 				break;
442 			}
443 		}
444 	}
445 
446 	if (nactive[0] == 0 || nactive[1] == 0)
447 		return (cxgbe_netmap_simple_rss(sc, vi, ifp, na));
448 
449 	MPASS(dq[0] != -1 && dq[1] != -1);
450 	if (nactive[0] > nactive[1]) {
451 		defq = dq[0];
452 		dq_norss = true;
453 	} else if (nactive[0] < nactive[1]) {
454 		defq = dq[1];
455 		dq_norss = true;
456 	} else {
457 		defq = dq[0];
458 		dq_norss = false;
459 	}
460 
461 	i = 0;
462 	nm_rxq = &sc->sge.nm_rxq[vi->first_nm_rxq];
463 	while (i < vi->rss_size / 2) {
464 		for (j = 0; j < (vi->nnmrxq + 1) / 2; j++) {
465 			nm_state = atomic_load_int(&nm_rxq[j].nm_state);
466 			kring = na->rx_rings[nm_rxq[j].nid];
467 			if ((nm_state == NM_OFF &&
468 			    !nm_kring_pending_on(kring)) ||
469 			    (nm_state == NM_ON &&
470 			    nm_kring_pending_off(kring))) {
471 				continue;
472 			}
473 			MPASS(nm_rxq[j].iq_cntxt_id != INVALID_NM_RXQ_CNTXT_ID);
474 			if (dq_norss && defq == nm_rxq[j].iq_abs_id)
475 				continue;
476 			vi->nm_rss[i++] = nm_rxq[j].iq_abs_id;
477 			if (i == vi->rss_size / 2)
478 				break;
479 		}
480 	}
481 	while (i < vi->rss_size) {
482 		for (j = (vi->nnmrxq + 1) / 2; j < vi->nnmrxq; j++) {
483 			nm_state = atomic_load_int(&nm_rxq[j].nm_state);
484 			kring = na->rx_rings[nm_rxq[j].nid];
485 			if ((nm_state == NM_OFF &&
486 			    !nm_kring_pending_on(kring)) ||
487 			    (nm_state == NM_ON &&
488 			    nm_kring_pending_off(kring))) {
489 				continue;
490 			}
491 			MPASS(nm_rxq[j].iq_cntxt_id != INVALID_NM_RXQ_CNTXT_ID);
492 			if (dq_norss && defq == nm_rxq[j].iq_abs_id)
493 				continue;
494 			vi->nm_rss[i++] = nm_rxq[j].iq_abs_id;
495 			if (i == vi->rss_size)
496 				break;
497 		}
498 	}
499 
500 	rc = -t4_config_rss_range(sc, sc->mbox, vi->viid, 0, vi->rss_size,
501 	    vi->nm_rss, vi->rss_size);
502 	if (rc != 0)
503 		if_printf(ifp, "netmap split_rss_config failed: %d\n", rc);
504 
505 	rc = -t4_config_vi_rss(sc, sc->mbox, vi->viid, vi->hashen, defq, 0, 0);
506 	if (rc != 0)
507 		if_printf(ifp, "netmap defaultq config failed: %d\n", rc);
508 
509 	return (rc);
510 }
511 
512 static inline int
513 cxgbe_netmap_rss(struct adapter *sc, struct vi_info *vi, struct ifnet *ifp,
514     struct netmap_adapter *na)
515 {
516 
517 	if (nm_split_rss == 0 || vi->nnmrxq == 1)
518 		return (cxgbe_netmap_simple_rss(sc, vi, ifp, na));
519 	else
520 		return (cxgbe_netmap_split_rss(sc, vi, ifp, na));
521 }
522 
523 static int
524 cxgbe_netmap_on(struct adapter *sc, struct vi_info *vi, struct ifnet *ifp,
525     struct netmap_adapter *na)
526 {
527 	struct netmap_slot *slot;
528 	struct netmap_kring *kring;
529 	struct sge_nm_rxq *nm_rxq;
530 	struct sge_nm_txq *nm_txq;
531 	int i, j, hwidx;
532 	struct rx_buf_info *rxb;
533 
534 	ASSERT_SYNCHRONIZED_OP(sc);
535 	MPASS(vi->nnmrxq > 0);
536 	MPASS(vi->nnmtxq > 0);
537 
538 	if ((vi->flags & VI_INIT_DONE) == 0 ||
539 	    (ifp->if_drv_flags & IFF_DRV_RUNNING) == 0)
540 		return (EAGAIN);
541 
542 	rxb = &sc->sge.rx_buf_info[0];
543 	for (i = 0; i < SW_ZONE_SIZES; i++, rxb++) {
544 		if (rxb->size1 == NETMAP_BUF_SIZE(na)) {
545 			hwidx = rxb->hwidx1;
546 			break;
547 		}
548 		if (rxb->size2 == NETMAP_BUF_SIZE(na)) {
549 			hwidx = rxb->hwidx2;
550 			break;
551 		}
552 	}
553 	if (i >= SW_ZONE_SIZES) {
554 		if_printf(ifp, "no hwidx for netmap buffer size %d.\n",
555 		    NETMAP_BUF_SIZE(na));
556 		return (ENXIO);
557 	}
558 
559 	/* Must set caps before calling netmap_reset */
560 	nm_set_native_flags(na);
561 
562 	for_each_nm_rxq(vi, i, nm_rxq) {
563 		kring = na->rx_rings[nm_rxq->nid];
564 		if (!nm_kring_pending_on(kring) ||
565 		    nm_rxq->iq_cntxt_id != INVALID_NM_RXQ_CNTXT_ID)
566 			continue;
567 
568 		alloc_nm_rxq_hwq(vi, nm_rxq, tnl_cong(vi->pi, nm_cong_drop));
569 		nm_rxq->fl_hwidx = hwidx;
570 		slot = netmap_reset(na, NR_RX, i, 0);
571 		MPASS(slot != NULL);	/* XXXNM: error check, not assert */
572 
573 		/* We deal with 8 bufs at a time */
574 		MPASS((na->num_rx_desc & 7) == 0);
575 		MPASS(na->num_rx_desc == nm_rxq->fl_sidx);
576 		for (j = 0; j < nm_rxq->fl_sidx; j++) {
577 			uint64_t ba;
578 
579 			PNMB(na, &slot[j], &ba);
580 			MPASS(ba != 0);
581 			nm_rxq->fl_desc[j] = htobe64(ba | hwidx);
582 		}
583 		j = nm_rxq->fl_pidx = nm_rxq->fl_sidx - 8;
584 		MPASS((j & 7) == 0);
585 		j /= 8;	/* driver pidx to hardware pidx */
586 		wmb();
587 		t4_write_reg(sc, sc->sge_kdoorbell_reg,
588 		    nm_rxq->fl_db_val | V_PIDX(j));
589 
590 		(void) atomic_cmpset_int(&nm_rxq->nm_state, NM_OFF, NM_ON);
591 	}
592 
593 	for_each_nm_txq(vi, i, nm_txq) {
594 		kring = na->tx_rings[nm_txq->nid];
595 		if (!nm_kring_pending_on(kring) ||
596 		    nm_txq->cntxt_id != INVALID_NM_TXQ_CNTXT_ID)
597 			continue;
598 
599 		alloc_nm_txq_hwq(vi, nm_txq);
600 		slot = netmap_reset(na, NR_TX, i, 0);
601 		MPASS(slot != NULL);	/* XXXNM: error check, not assert */
602 	}
603 
604 	if (vi->nm_rss == NULL) {
605 		vi->nm_rss = malloc(vi->rss_size * sizeof(uint16_t), M_CXGBE,
606 		    M_ZERO | M_WAITOK);
607 	}
608 
609 	return (cxgbe_netmap_rss(sc, vi, ifp, na));
610 }
611 
612 static int
613 cxgbe_netmap_off(struct adapter *sc, struct vi_info *vi, struct ifnet *ifp,
614     struct netmap_adapter *na)
615 {
616 	struct netmap_kring *kring;
617 	int rc, i, nm_state, nactive;
618 	struct sge_nm_txq *nm_txq;
619 	struct sge_nm_rxq *nm_rxq;
620 
621 	ASSERT_SYNCHRONIZED_OP(sc);
622 	MPASS(vi->nnmrxq > 0);
623 	MPASS(vi->nnmtxq > 0);
624 
625 	if (!nm_netmap_on(na))
626 		return (0);
627 
628 	if ((vi->flags & VI_INIT_DONE) == 0)
629 		return (0);
630 
631 	/* First remove the queues that are stopping from the RSS table. */
632 	rc = cxgbe_netmap_rss(sc, vi, ifp, na);
633 	if (rc != 0)
634 		return (rc);	/* error message logged already. */
635 
636 	for_each_nm_txq(vi, i, nm_txq) {
637 		struct sge_qstat *spg = (void *)&nm_txq->desc[nm_txq->sidx];
638 
639 		kring = na->tx_rings[nm_txq->nid];
640 		if (!nm_kring_pending_off(kring) ||
641 		    nm_txq->cntxt_id == INVALID_NM_TXQ_CNTXT_ID)
642 			continue;
643 
644 		/* Wait for hw pidx to catch up ... */
645 		while (be16toh(nm_txq->pidx) != spg->pidx)
646 			pause("nmpidx", 1);
647 
648 		/* ... and then for the cidx. */
649 		while (spg->pidx != spg->cidx)
650 			pause("nmcidx", 1);
651 
652 		free_nm_txq_hwq(vi, nm_txq);
653 
654 		/* XXX: netmap, not the driver, should do this. */
655 		kring->rhead = kring->rcur = kring->nr_hwcur = 0;
656 		kring->rtail = kring->nr_hwtail = kring->nkr_num_slots - 1;
657 	}
658 	nactive = 0;
659 	for_each_nm_rxq(vi, i, nm_rxq) {
660 		nm_state = atomic_load_int(&nm_rxq->nm_state);
661 		kring = na->rx_rings[nm_rxq->nid];
662 		if (nm_state != NM_OFF && !nm_kring_pending_off(kring))
663 			nactive++;
664 		if (nm_state == NM_OFF || !nm_kring_pending_off(kring))
665 			continue;
666 
667 		MPASS(nm_rxq->iq_cntxt_id != INVALID_NM_RXQ_CNTXT_ID);
668 		while (!atomic_cmpset_int(&nm_rxq->nm_state, NM_ON, NM_OFF))
669 			pause("nmst", 1);
670 
671 		free_nm_rxq_hwq(vi, nm_rxq);
672 
673 		/* XXX: netmap, not the driver, should do this. */
674 		kring->rhead = kring->rcur = kring->nr_hwcur = 0;
675 		kring->rtail = kring->nr_hwtail = 0;
676 	}
677 	netmap_krings_mode_commit(na, 0);
678 	if (nactive == 0)
679 		nm_clear_native_flags(na);
680 
681 	return (rc);
682 }
683 
684 static int
685 cxgbe_netmap_reg(struct netmap_adapter *na, int on)
686 {
687 	struct ifnet *ifp = na->ifp;
688 	struct vi_info *vi = ifp->if_softc;
689 	struct adapter *sc = vi->adapter;
690 	int rc;
691 
692 	rc = begin_synchronized_op(sc, vi, SLEEP_OK | INTR_OK, "t4nmreg");
693 	if (rc != 0)
694 		return (rc);
695 	if (on)
696 		rc = cxgbe_netmap_on(sc, vi, ifp, na);
697 	else
698 		rc = cxgbe_netmap_off(sc, vi, ifp, na);
699 	end_synchronized_op(sc, 0);
700 
701 	return (rc);
702 }
703 
704 /* How many packets can a single type1 WR carry in n descriptors */
705 static inline int
706 ndesc_to_npkt(const int n)
707 {
708 
709 	MPASS(n > 0 && n <= SGE_MAX_WR_NDESC);
710 
711 	return (n * 2 - 1);
712 }
713 #define MAX_NPKT_IN_TYPE1_WR	(ndesc_to_npkt(SGE_MAX_WR_NDESC))
714 
715 /*
716  * Space (in descriptors) needed for a type1 WR (TX_PKTS or TX_PKTS2) that
717  * carries n packets
718  */
719 static inline int
720 npkt_to_ndesc(const int n)
721 {
722 
723 	MPASS(n > 0 && n <= MAX_NPKT_IN_TYPE1_WR);
724 
725 	return ((n + 2) / 2);
726 }
727 
728 /*
729  * Space (in 16B units) needed for a type1 WR (TX_PKTS or TX_PKTS2) that
730  * carries n packets
731  */
732 static inline int
733 npkt_to_len16(const int n)
734 {
735 
736 	MPASS(n > 0 && n <= MAX_NPKT_IN_TYPE1_WR);
737 
738 	return (n * 2 + 1);
739 }
740 
741 #define NMIDXDIFF(q, idx) IDXDIFF((q)->pidx, (q)->idx, (q)->sidx)
742 
743 static void
744 ring_nm_txq_db(struct adapter *sc, struct sge_nm_txq *nm_txq)
745 {
746 	int n;
747 	u_int db = nm_txq->doorbells;
748 
749 	MPASS(nm_txq->pidx != nm_txq->dbidx);
750 
751 	n = NMIDXDIFF(nm_txq, dbidx);
752 	if (n > 1)
753 		clrbit(&db, DOORBELL_WCWR);
754 	wmb();
755 
756 	switch (ffs(db) - 1) {
757 	case DOORBELL_UDB:
758 		*nm_txq->udb = htole32(V_QID(nm_txq->udb_qid) | V_PIDX(n));
759 		break;
760 
761 	case DOORBELL_WCWR: {
762 		volatile uint64_t *dst, *src;
763 
764 		/*
765 		 * Queues whose 128B doorbell segment fits in the page do not
766 		 * use relative qid (udb_qid is always 0).  Only queues with
767 		 * doorbell segments can do WCWR.
768 		 */
769 		KASSERT(nm_txq->udb_qid == 0 && n == 1,
770 		    ("%s: inappropriate doorbell (0x%x, %d, %d) for nm_txq %p",
771 		    __func__, nm_txq->doorbells, n, nm_txq->pidx, nm_txq));
772 
773 		dst = (volatile void *)((uintptr_t)nm_txq->udb +
774 		    UDBS_WR_OFFSET - UDBS_DB_OFFSET);
775 		src = (void *)&nm_txq->desc[nm_txq->dbidx];
776 		while (src != (void *)&nm_txq->desc[nm_txq->dbidx + 1])
777 			*dst++ = *src++;
778 		wmb();
779 		break;
780 	}
781 
782 	case DOORBELL_UDBWC:
783 		*nm_txq->udb = htole32(V_QID(nm_txq->udb_qid) | V_PIDX(n));
784 		wmb();
785 		break;
786 
787 	case DOORBELL_KDB:
788 		t4_write_reg(sc, sc->sge_kdoorbell_reg,
789 		    V_QID(nm_txq->cntxt_id) | V_PIDX(n));
790 		break;
791 	}
792 	nm_txq->dbidx = nm_txq->pidx;
793 }
794 
795 /*
796  * Write work requests to send 'npkt' frames and ring the doorbell to send them
797  * on their way.  No need to check for wraparound.
798  */
799 static void
800 cxgbe_nm_tx(struct adapter *sc, struct sge_nm_txq *nm_txq,
801     struct netmap_kring *kring, int npkt, int npkt_remaining)
802 {
803 	struct netmap_ring *ring = kring->ring;
804 	struct netmap_slot *slot;
805 	const u_int lim = kring->nkr_num_slots - 1;
806 	struct fw_eth_tx_pkts_wr *wr = (void *)&nm_txq->desc[nm_txq->pidx];
807 	uint16_t len;
808 	uint64_t ba;
809 	struct cpl_tx_pkt_core *cpl;
810 	struct ulptx_sgl *usgl;
811 	int i, n;
812 
813 	while (npkt) {
814 		n = min(npkt, MAX_NPKT_IN_TYPE1_WR);
815 		len = 0;
816 
817 		wr = (void *)&nm_txq->desc[nm_txq->pidx];
818 		wr->op_pkd = nm_txq->op_pkd;
819 		wr->equiq_to_len16 = htobe32(V_FW_WR_LEN16(npkt_to_len16(n)));
820 		wr->npkt = n;
821 		wr->r3 = 0;
822 		wr->type = 1;
823 		cpl = (void *)(wr + 1);
824 
825 		for (i = 0; i < n; i++) {
826 			slot = &ring->slot[kring->nr_hwcur];
827 			PNMB(kring->na, slot, &ba);
828 			MPASS(ba != 0);
829 
830 			cpl->ctrl0 = nm_txq->cpl_ctrl0;
831 			cpl->pack = 0;
832 			cpl->len = htobe16(slot->len);
833 			cpl->ctrl1 = nm_txcsum ? 0 :
834 			    htobe64(F_TXPKT_IPCSUM_DIS | F_TXPKT_L4CSUM_DIS);
835 
836 			usgl = (void *)(cpl + 1);
837 			usgl->cmd_nsge = htobe32(V_ULPTX_CMD(ULP_TX_SC_DSGL) |
838 			    V_ULPTX_NSGE(1));
839 			usgl->len0 = htobe32(slot->len);
840 			usgl->addr0 = htobe64(ba);
841 
842 			slot->flags &= ~(NS_REPORT | NS_BUF_CHANGED);
843 			cpl = (void *)(usgl + 1);
844 			MPASS(slot->len + len <= UINT16_MAX);
845 			len += slot->len;
846 			kring->nr_hwcur = nm_next(kring->nr_hwcur, lim);
847 		}
848 		wr->plen = htobe16(len);
849 
850 		npkt -= n;
851 		nm_txq->pidx += npkt_to_ndesc(n);
852 		MPASS(nm_txq->pidx <= nm_txq->sidx);
853 		if (__predict_false(nm_txq->pidx == nm_txq->sidx)) {
854 			/*
855 			 * This routine doesn't know how to write WRs that wrap
856 			 * around.  Make sure it wasn't asked to.
857 			 */
858 			MPASS(npkt == 0);
859 			nm_txq->pidx = 0;
860 		}
861 
862 		if (npkt == 0 && npkt_remaining == 0) {
863 			/* All done. */
864 			if (lazy_tx_credit_flush == 0) {
865 				wr->equiq_to_len16 |= htobe32(F_FW_WR_EQUEQ |
866 				    F_FW_WR_EQUIQ);
867 				nm_txq->equeqidx = nm_txq->pidx;
868 				nm_txq->equiqidx = nm_txq->pidx;
869 			}
870 			ring_nm_txq_db(sc, nm_txq);
871 			return;
872 		}
873 
874 		if (NMIDXDIFF(nm_txq, equiqidx) >= nm_txq->sidx / 2) {
875 			wr->equiq_to_len16 |= htobe32(F_FW_WR_EQUEQ |
876 			    F_FW_WR_EQUIQ);
877 			nm_txq->equeqidx = nm_txq->pidx;
878 			nm_txq->equiqidx = nm_txq->pidx;
879 		} else if (NMIDXDIFF(nm_txq, equeqidx) >= 64) {
880 			wr->equiq_to_len16 |= htobe32(F_FW_WR_EQUEQ);
881 			nm_txq->equeqidx = nm_txq->pidx;
882 		}
883 		if (NMIDXDIFF(nm_txq, dbidx) >= 2 * SGE_MAX_WR_NDESC)
884 			ring_nm_txq_db(sc, nm_txq);
885 	}
886 
887 	/* Will get called again. */
888 	MPASS(npkt_remaining);
889 }
890 
891 /* How many contiguous free descriptors starting at pidx */
892 static inline int
893 contiguous_ndesc_available(struct sge_nm_txq *nm_txq)
894 {
895 
896 	if (nm_txq->cidx > nm_txq->pidx)
897 		return (nm_txq->cidx - nm_txq->pidx - 1);
898 	else if (nm_txq->cidx > 0)
899 		return (nm_txq->sidx - nm_txq->pidx);
900 	else
901 		return (nm_txq->sidx - nm_txq->pidx - 1);
902 }
903 
904 static int
905 reclaim_nm_tx_desc(struct sge_nm_txq *nm_txq)
906 {
907 	struct sge_qstat *spg = (void *)&nm_txq->desc[nm_txq->sidx];
908 	uint16_t hw_cidx = spg->cidx;	/* snapshot */
909 	struct fw_eth_tx_pkts_wr *wr;
910 	int n = 0;
911 
912 	hw_cidx = be16toh(hw_cidx);
913 
914 	while (nm_txq->cidx != hw_cidx) {
915 		wr = (void *)&nm_txq->desc[nm_txq->cidx];
916 
917 		MPASS(wr->op_pkd == htobe32(V_FW_WR_OP(FW_ETH_TX_PKTS_WR)) ||
918 		    wr->op_pkd == htobe32(V_FW_WR_OP(FW_ETH_TX_PKTS2_WR)));
919 		MPASS(wr->type == 1);
920 		MPASS(wr->npkt > 0 && wr->npkt <= MAX_NPKT_IN_TYPE1_WR);
921 
922 		n += wr->npkt;
923 		nm_txq->cidx += npkt_to_ndesc(wr->npkt);
924 
925 		/*
926 		 * We never sent a WR that wrapped around so the credits coming
927 		 * back, WR by WR, should never cause the cidx to wrap around
928 		 * either.
929 		 */
930 		MPASS(nm_txq->cidx <= nm_txq->sidx);
931 		if (__predict_false(nm_txq->cidx == nm_txq->sidx))
932 			nm_txq->cidx = 0;
933 	}
934 
935 	return (n);
936 }
937 
938 static int
939 cxgbe_netmap_txsync(struct netmap_kring *kring, int flags)
940 {
941 	struct netmap_adapter *na = kring->na;
942 	struct ifnet *ifp = na->ifp;
943 	struct vi_info *vi = ifp->if_softc;
944 	struct adapter *sc = vi->adapter;
945 	struct sge_nm_txq *nm_txq = &sc->sge.nm_txq[vi->first_nm_txq + kring->ring_id];
946 	const u_int head = kring->rhead;
947 	u_int reclaimed = 0;
948 	int n, d, npkt_remaining, ndesc_remaining;
949 
950 	/*
951 	 * Tx was at kring->nr_hwcur last time around and now we need to advance
952 	 * to kring->rhead.  Note that the driver's pidx moves independent of
953 	 * netmap's kring->nr_hwcur (pidx counts descriptors and the relation
954 	 * between descriptors and frames isn't 1:1).
955 	 */
956 
957 	npkt_remaining = head >= kring->nr_hwcur ? head - kring->nr_hwcur :
958 	    kring->nkr_num_slots - kring->nr_hwcur + head;
959 	while (npkt_remaining) {
960 		reclaimed += reclaim_nm_tx_desc(nm_txq);
961 		ndesc_remaining = contiguous_ndesc_available(nm_txq);
962 		/* Can't run out of descriptors with packets still remaining */
963 		MPASS(ndesc_remaining > 0);
964 
965 		/* # of desc needed to tx all remaining packets */
966 		d = (npkt_remaining / MAX_NPKT_IN_TYPE1_WR) * SGE_MAX_WR_NDESC;
967 		if (npkt_remaining % MAX_NPKT_IN_TYPE1_WR)
968 			d += npkt_to_ndesc(npkt_remaining % MAX_NPKT_IN_TYPE1_WR);
969 
970 		if (d <= ndesc_remaining)
971 			n = npkt_remaining;
972 		else {
973 			/* Can't send all, calculate how many can be sent */
974 			n = (ndesc_remaining / SGE_MAX_WR_NDESC) *
975 			    MAX_NPKT_IN_TYPE1_WR;
976 			if (ndesc_remaining % SGE_MAX_WR_NDESC)
977 				n += ndesc_to_npkt(ndesc_remaining % SGE_MAX_WR_NDESC);
978 		}
979 
980 		/* Send n packets and update nm_txq->pidx and kring->nr_hwcur */
981 		npkt_remaining -= n;
982 		cxgbe_nm_tx(sc, nm_txq, kring, n, npkt_remaining);
983 	}
984 	MPASS(npkt_remaining == 0);
985 	MPASS(kring->nr_hwcur == head);
986 	MPASS(nm_txq->dbidx == nm_txq->pidx);
987 
988 	/*
989 	 * Second part: reclaim buffers for completed transmissions.
990 	 */
991 	if (reclaimed || flags & NAF_FORCE_RECLAIM || nm_kr_txempty(kring)) {
992 		reclaimed += reclaim_nm_tx_desc(nm_txq);
993 		kring->nr_hwtail += reclaimed;
994 		if (kring->nr_hwtail >= kring->nkr_num_slots)
995 			kring->nr_hwtail -= kring->nkr_num_slots;
996 	}
997 
998 	return (0);
999 }
1000 
1001 static int
1002 cxgbe_netmap_rxsync(struct netmap_kring *kring, int flags)
1003 {
1004 	struct netmap_adapter *na = kring->na;
1005 	struct netmap_ring *ring = kring->ring;
1006 	struct ifnet *ifp = na->ifp;
1007 	struct vi_info *vi = ifp->if_softc;
1008 	struct adapter *sc = vi->adapter;
1009 	struct sge_nm_rxq *nm_rxq = &sc->sge.nm_rxq[vi->first_nm_rxq + kring->ring_id];
1010 	u_int const head = kring->rhead;
1011 	u_int n;
1012 	int force_update = (flags & NAF_FORCE_READ) || kring->nr_kflags & NKR_PENDINTR;
1013 
1014 	if (black_hole)
1015 		return (0);	/* No updates ever. */
1016 
1017 	if (netmap_no_pendintr || force_update) {
1018 		kring->nr_hwtail = atomic_load_acq_32(&nm_rxq->fl_cidx);
1019 		kring->nr_kflags &= ~NKR_PENDINTR;
1020 	}
1021 
1022 	if (nm_rxq->fl_db_saved > 0 && starve_fl == 0) {
1023 		wmb();
1024 		t4_write_reg(sc, sc->sge_kdoorbell_reg,
1025 		    nm_rxq->fl_db_val | V_PIDX(nm_rxq->fl_db_saved));
1026 		nm_rxq->fl_db_saved = 0;
1027 	}
1028 
1029 	/* Userspace done with buffers from kring->nr_hwcur to head */
1030 	n = head >= kring->nr_hwcur ? head - kring->nr_hwcur :
1031 	    kring->nkr_num_slots - kring->nr_hwcur + head;
1032 	n &= ~7U;
1033 	if (n > 0) {
1034 		u_int fl_pidx = nm_rxq->fl_pidx;
1035 		struct netmap_slot *slot = &ring->slot[fl_pidx];
1036 		uint64_t ba;
1037 		int i, dbinc = 0, hwidx = nm_rxq->fl_hwidx;
1038 
1039 		/*
1040 		 * We always deal with 8 buffers at a time.  We must have
1041 		 * stopped at an 8B boundary (fl_pidx) last time around and we
1042 		 * must have a multiple of 8B buffers to give to the freelist.
1043 		 */
1044 		MPASS((fl_pidx & 7) == 0);
1045 		MPASS((n & 7) == 0);
1046 
1047 		IDXINCR(kring->nr_hwcur, n, kring->nkr_num_slots);
1048 		IDXINCR(nm_rxq->fl_pidx, n, nm_rxq->fl_sidx2);
1049 
1050 		while (n > 0) {
1051 			for (i = 0; i < 8; i++, fl_pidx++, slot++) {
1052 				PNMB(na, slot, &ba);
1053 				MPASS(ba != 0);
1054 				nm_rxq->fl_desc[fl_pidx] = htobe64(ba | hwidx);
1055 				slot->flags &= ~NS_BUF_CHANGED;
1056 				MPASS(fl_pidx <= nm_rxq->fl_sidx2);
1057 			}
1058 			n -= 8;
1059 			if (fl_pidx == nm_rxq->fl_sidx2) {
1060 				fl_pidx = 0;
1061 				slot = &ring->slot[0];
1062 			}
1063 			if (++dbinc == 8 && n >= 32) {
1064 				wmb();
1065 				if (starve_fl)
1066 					nm_rxq->fl_db_saved += dbinc;
1067 				else {
1068 					t4_write_reg(sc, sc->sge_kdoorbell_reg,
1069 					    nm_rxq->fl_db_val | V_PIDX(dbinc));
1070 				}
1071 				dbinc = 0;
1072 			}
1073 		}
1074 		MPASS(nm_rxq->fl_pidx == fl_pidx);
1075 
1076 		if (dbinc > 0) {
1077 			wmb();
1078 			if (starve_fl)
1079 				nm_rxq->fl_db_saved += dbinc;
1080 			else {
1081 				t4_write_reg(sc, sc->sge_kdoorbell_reg,
1082 				    nm_rxq->fl_db_val | V_PIDX(dbinc));
1083 			}
1084 		}
1085 	}
1086 
1087 	return (0);
1088 }
1089 
1090 void
1091 cxgbe_nm_attach(struct vi_info *vi)
1092 {
1093 	struct port_info *pi;
1094 	struct adapter *sc;
1095 	struct netmap_adapter na;
1096 
1097 	MPASS(vi->nnmrxq > 0);
1098 	MPASS(vi->ifp != NULL);
1099 
1100 	pi = vi->pi;
1101 	sc = pi->adapter;
1102 
1103 	bzero(&na, sizeof(na));
1104 
1105 	na.ifp = vi->ifp;
1106 	na.na_flags = NAF_BDG_MAYSLEEP;
1107 
1108 	/* Netmap doesn't know about the space reserved for the status page. */
1109 	na.num_tx_desc = vi->qsize_txq - sc->params.sge.spg_len / EQ_ESIZE;
1110 
1111 	/*
1112 	 * The freelist's cidx/pidx drives netmap's rx cidx/pidx.  So
1113 	 * num_rx_desc is based on the number of buffers that can be held in the
1114 	 * freelist, and not the number of entries in the iq.  (These two are
1115 	 * not exactly the same due to the space taken up by the status page).
1116 	 */
1117 	na.num_rx_desc = rounddown(vi->qsize_rxq, 8);
1118 	na.nm_txsync = cxgbe_netmap_txsync;
1119 	na.nm_rxsync = cxgbe_netmap_rxsync;
1120 	na.nm_register = cxgbe_netmap_reg;
1121 	na.num_tx_rings = vi->nnmtxq;
1122 	na.num_rx_rings = vi->nnmrxq;
1123 	na.rx_buf_maxsize = MAX_MTU;
1124 	netmap_attach(&na);	/* This adds IFCAP_NETMAP to if_capabilities */
1125 }
1126 
1127 void
1128 cxgbe_nm_detach(struct vi_info *vi)
1129 {
1130 
1131 	MPASS(vi->nnmrxq > 0);
1132 	MPASS(vi->ifp != NULL);
1133 
1134 	netmap_detach(vi->ifp);
1135 }
1136 
1137 static inline const void *
1138 unwrap_nm_fw6_msg(const struct cpl_fw6_msg *cpl)
1139 {
1140 
1141 	MPASS(cpl->type == FW_TYPE_RSSCPL || cpl->type == FW6_TYPE_RSSCPL);
1142 
1143 	/* data[0] is RSS header */
1144 	return (&cpl->data[1]);
1145 }
1146 
1147 static void
1148 handle_nm_sge_egr_update(struct adapter *sc, struct ifnet *ifp,
1149     const struct cpl_sge_egr_update *egr)
1150 {
1151 	uint32_t oq;
1152 	struct sge_nm_txq *nm_txq;
1153 
1154 	oq = be32toh(egr->opcode_qid);
1155 	MPASS(G_CPL_OPCODE(oq) == CPL_SGE_EGR_UPDATE);
1156 	nm_txq = (void *)sc->sge.eqmap[G_EGR_QID(oq) - sc->sge.eq_start];
1157 
1158 	netmap_tx_irq(ifp, nm_txq->nid);
1159 }
1160 
1161 void
1162 service_nm_rxq(struct sge_nm_rxq *nm_rxq)
1163 {
1164 	struct vi_info *vi = nm_rxq->vi;
1165 	struct adapter *sc = vi->adapter;
1166 	struct ifnet *ifp = vi->ifp;
1167 	struct netmap_adapter *na = NA(ifp);
1168 	struct netmap_kring *kring = na->rx_rings[nm_rxq->nid];
1169 	struct netmap_ring *ring = kring->ring;
1170 	struct iq_desc *d = &nm_rxq->iq_desc[nm_rxq->iq_cidx];
1171 	const void *cpl;
1172 	uint32_t lq;
1173 	u_int work = 0;
1174 	uint8_t opcode;
1175 	uint32_t fl_cidx = atomic_load_acq_32(&nm_rxq->fl_cidx);
1176 	u_int fl_credits = fl_cidx & 7;
1177 	u_int ndesc = 0;	/* desc processed since last cidx update */
1178 	u_int nframes = 0;	/* frames processed since last netmap wakeup */
1179 
1180 	while ((d->rsp.u.type_gen & F_RSPD_GEN) == nm_rxq->iq_gen) {
1181 
1182 		rmb();
1183 
1184 		lq = be32toh(d->rsp.pldbuflen_qid);
1185 		opcode = d->rss.opcode;
1186 		cpl = &d->cpl[0];
1187 
1188 		switch (G_RSPD_TYPE(d->rsp.u.type_gen)) {
1189 		case X_RSPD_TYPE_FLBUF:
1190 
1191 			/* fall through */
1192 
1193 		case X_RSPD_TYPE_CPL:
1194 			MPASS(opcode < NUM_CPL_CMDS);
1195 
1196 			switch (opcode) {
1197 			case CPL_FW4_MSG:
1198 			case CPL_FW6_MSG:
1199 				cpl = unwrap_nm_fw6_msg(cpl);
1200 				/* fall through */
1201 			case CPL_SGE_EGR_UPDATE:
1202 				handle_nm_sge_egr_update(sc, ifp, cpl);
1203 				break;
1204 			case CPL_RX_PKT:
1205 				ring->slot[fl_cidx].len = G_RSPD_LEN(lq) -
1206 				    sc->params.sge.fl_pktshift;
1207 				ring->slot[fl_cidx].flags = 0;
1208 				nframes++;
1209 				if (!(lq & F_RSPD_NEWBUF)) {
1210 					MPASS(black_hole == 2);
1211 					break;
1212 				}
1213 				fl_credits++;
1214 				if (__predict_false(++fl_cidx == nm_rxq->fl_sidx))
1215 					fl_cidx = 0;
1216 				break;
1217 			default:
1218 				panic("%s: unexpected opcode 0x%x on nm_rxq %p",
1219 				    __func__, opcode, nm_rxq);
1220 			}
1221 			break;
1222 
1223 		case X_RSPD_TYPE_INTR:
1224 			/* Not equipped to handle forwarded interrupts. */
1225 			panic("%s: netmap queue received interrupt for iq %u\n",
1226 			    __func__, lq);
1227 
1228 		default:
1229 			panic("%s: illegal response type %d on nm_rxq %p",
1230 			    __func__, G_RSPD_TYPE(d->rsp.u.type_gen), nm_rxq);
1231 		}
1232 
1233 		d++;
1234 		if (__predict_false(++nm_rxq->iq_cidx == nm_rxq->iq_sidx)) {
1235 			nm_rxq->iq_cidx = 0;
1236 			d = &nm_rxq->iq_desc[0];
1237 			nm_rxq->iq_gen ^= F_RSPD_GEN;
1238 		}
1239 
1240 		if (__predict_false(++nframes == rx_nframes) && !black_hole) {
1241 			atomic_store_rel_32(&nm_rxq->fl_cidx, fl_cidx);
1242 			netmap_rx_irq(ifp, nm_rxq->nid, &work);
1243 			nframes = 0;
1244 		}
1245 
1246 		if (__predict_false(++ndesc == rx_ndesc)) {
1247 			if (black_hole && fl_credits >= 8) {
1248 				fl_credits /= 8;
1249 				IDXINCR(nm_rxq->fl_pidx, fl_credits * 8,
1250 				    nm_rxq->fl_sidx);
1251 				t4_write_reg(sc, sc->sge_kdoorbell_reg,
1252 				    nm_rxq->fl_db_val | V_PIDX(fl_credits));
1253 				fl_credits = fl_cidx & 7;
1254 			}
1255 			t4_write_reg(sc, sc->sge_gts_reg,
1256 			    V_CIDXINC(ndesc) |
1257 			    V_INGRESSQID(nm_rxq->iq_cntxt_id) |
1258 			    V_SEINTARM(V_QINTR_TIMER_IDX(X_TIMERREG_UPDATE_CIDX)));
1259 			ndesc = 0;
1260 		}
1261 	}
1262 
1263 	atomic_store_rel_32(&nm_rxq->fl_cidx, fl_cidx);
1264 	if (black_hole) {
1265 		fl_credits /= 8;
1266 		IDXINCR(nm_rxq->fl_pidx, fl_credits * 8, nm_rxq->fl_sidx);
1267 		t4_write_reg(sc, sc->sge_kdoorbell_reg,
1268 		    nm_rxq->fl_db_val | V_PIDX(fl_credits));
1269 	} else if (nframes > 0)
1270 		netmap_rx_irq(ifp, nm_rxq->nid, &work);
1271 
1272     	t4_write_reg(sc, sc->sge_gts_reg, V_CIDXINC(ndesc) |
1273 	    V_INGRESSQID((u32)nm_rxq->iq_cntxt_id) |
1274 	    V_SEINTARM(V_QINTR_TIMER_IDX(holdoff_tmr_idx)));
1275 }
1276 #endif
1277