xref: /freebsd/sys/dev/e1000/em_txrx.c (revision 2e3f49888ec8851bafb22011533217487764fdb0)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2016 Nicole Graziano <nicole@nextbsd.org>
5  * Copyright (c) 2017 Matthew Macy <mmacy@mattmacy.io>
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include "if_em.h"
31 
32 #ifdef RSS
33 #include <net/rss_config.h>
34 #include <netinet/in_rss.h>
35 #endif
36 
37 #ifdef VERBOSE_DEBUG
38 #define DPRINTF device_printf
39 #else
40 #define DPRINTF(...)
41 #endif
42 
43 /*********************************************************************
44  *  Local Function prototypes
45  *********************************************************************/
46 static int em_tso_setup(struct e1000_softc *sc, if_pkt_info_t pi,
47     uint32_t *txd_upper, uint32_t *txd_lower);
48 static int em_transmit_checksum_setup(struct e1000_softc *sc,
49     if_pkt_info_t pi, uint32_t *txd_upper, uint32_t *txd_lower);
50 static int em_isc_txd_encap(void *arg, if_pkt_info_t pi);
51 static void em_isc_txd_flush(void *arg, uint16_t txqid, qidx_t pidx);
52 static int em_isc_txd_credits_update(void *arg, uint16_t txqid, bool clear);
53 static void em_isc_rxd_refill(void *arg, if_rxd_update_t iru);
54 static void em_isc_rxd_flush(void *arg, uint16_t rxqid, uint8_t flid __unused,
55     qidx_t pidx);
56 static int em_isc_rxd_available(void *arg, uint16_t rxqid, qidx_t idx,
57     qidx_t budget);
58 static int em_isc_rxd_pkt_get(void *arg, if_rxd_info_t ri);
59 
60 static void lem_isc_rxd_refill(void *arg, if_rxd_update_t iru);
61 
62 static int lem_isc_rxd_available(void *arg, uint16_t rxqid, qidx_t idx,
63    qidx_t budget);
64 static int lem_isc_rxd_pkt_get(void *arg, if_rxd_info_t ri);
65 
66 static void em_receive_checksum(uint16_t, uint8_t, if_rxd_info_t);
67 static int em_determine_rsstype(uint32_t pkt_info);
68 extern int em_intr(void *arg);
69 
70 struct if_txrx em_txrx = {
71 	.ift_txd_encap = em_isc_txd_encap,
72 	.ift_txd_flush = em_isc_txd_flush,
73 	.ift_txd_credits_update = em_isc_txd_credits_update,
74 	.ift_rxd_available = em_isc_rxd_available,
75 	.ift_rxd_pkt_get = em_isc_rxd_pkt_get,
76 	.ift_rxd_refill = em_isc_rxd_refill,
77 	.ift_rxd_flush = em_isc_rxd_flush,
78 	.ift_legacy_intr = em_intr
79 };
80 
81 struct if_txrx lem_txrx = {
82 	.ift_txd_encap = em_isc_txd_encap,
83 	.ift_txd_flush = em_isc_txd_flush,
84 	.ift_txd_credits_update = em_isc_txd_credits_update,
85 	.ift_rxd_available = lem_isc_rxd_available,
86 	.ift_rxd_pkt_get = lem_isc_rxd_pkt_get,
87 	.ift_rxd_refill = lem_isc_rxd_refill,
88 	.ift_rxd_flush = em_isc_rxd_flush,
89 	.ift_legacy_intr = em_intr
90 };
91 
92 extern if_shared_ctx_t em_sctx;
93 
94 void
95 em_dump_rs(struct e1000_softc *sc)
96 {
97 	if_softc_ctx_t scctx = sc->shared;
98 	struct em_tx_queue *que;
99 	struct tx_ring *txr;
100 	qidx_t i, ntxd, qid, cur;
101 	int16_t rs_cidx;
102 	uint8_t status;
103 
104 	printf("\n");
105 	ntxd = scctx->isc_ntxd[0];
106 	for (qid = 0; qid < sc->tx_num_queues; qid++) {
107 		que = &sc->tx_queues[qid];
108 		txr =  &que->txr;
109 		rs_cidx = txr->tx_rs_cidx;
110 		if (rs_cidx != txr->tx_rs_pidx) {
111 			cur = txr->tx_rsq[rs_cidx];
112 			status = txr->tx_base[cur].upper.fields.status;
113 			if (!(status & E1000_TXD_STAT_DD))
114 				printf("qid[%d]->tx_rsq[%d]: %d clear ", qid, rs_cidx, cur);
115 		} else {
116 			rs_cidx = (rs_cidx-1)&(ntxd-1);
117 			cur = txr->tx_rsq[rs_cidx];
118 			printf("qid[%d]->tx_rsq[rs_cidx-1=%d]: %d  ", qid, rs_cidx, cur);
119 		}
120 		printf("cidx_prev=%d rs_pidx=%d ",txr->tx_cidx_processed,
121 		    txr->tx_rs_pidx);
122 		for (i = 0; i < ntxd; i++) {
123 			if (txr->tx_base[i].upper.fields.status & E1000_TXD_STAT_DD)
124 				printf("%d set ", i);
125 		}
126 		printf("\n");
127 	}
128 }
129 
130 /**********************************************************************
131  *
132  *  Setup work for hardware segmentation offload (TSO) on
133  *  adapters using advanced tx descriptors
134  *
135  **********************************************************************/
136 static int
137 em_tso_setup(struct e1000_softc *sc, if_pkt_info_t pi, uint32_t *txd_upper,
138     uint32_t *txd_lower)
139 {
140 	if_softc_ctx_t scctx = sc->shared;
141 	struct em_tx_queue *que = &sc->tx_queues[pi->ipi_qsidx];
142 	struct tx_ring *txr = &que->txr;
143 	struct e1000_context_desc *TXD;
144 	int cur, hdr_len;
145 	uint32_t cmd_type_len;
146 
147 	hdr_len = pi->ipi_ehdrlen + pi->ipi_ip_hlen + pi->ipi_tcp_hlen;
148 	*txd_lower = (E1000_TXD_CMD_DEXT |	/* Extended descr type */
149 		      E1000_TXD_DTYP_D |	/* Data descr type */
150 		      E1000_TXD_CMD_TSE);	/* Do TSE on this packet */
151 
152 	cur = pi->ipi_pidx;
153 	TXD = (struct e1000_context_desc *)&txr->tx_base[cur];
154 
155 	/*
156 	 * ipcss - Start offset for header checksum calculation.
157 	 * ipcse - End offset for header checksum calculation.
158 	 * ipcso - Offset of place to put the checksum.
159 	 */
160 	switch(pi->ipi_etype) {
161 	case ETHERTYPE_IP:
162 		/* IP and/or TCP header checksum calculation and insertion. */
163 		*txd_upper = (E1000_TXD_POPTS_IXSM | E1000_TXD_POPTS_TXSM) << 8;
164 
165 		TXD->lower_setup.ip_fields.ipcse =
166 		    htole16(pi->ipi_ehdrlen + pi->ipi_ip_hlen - 1);
167 		break;
168 	case ETHERTYPE_IPV6:
169 		/* TCP header checksum calculation and insertion. */
170 		*txd_upper = E1000_TXD_POPTS_TXSM << 8;
171 
172 		TXD->lower_setup.ip_fields.ipcse = htole16(0);
173 		break;
174 	default:
175 		break;
176 	}
177 	TXD->lower_setup.ip_fields.ipcss = pi->ipi_ehdrlen;
178 	TXD->lower_setup.ip_fields.ipcso =
179 	    pi->ipi_ehdrlen + offsetof(struct ip, ip_sum);
180 
181 	/*
182 	 * tucss - Start offset for payload checksum calculation.
183 	 * tucse - End offset for payload checksum calculation.
184 	 * tucso - Offset of place to put the checksum.
185 	 */
186 	TXD->upper_setup.tcp_fields.tucss = pi->ipi_ehdrlen + pi->ipi_ip_hlen;
187 	TXD->upper_setup.tcp_fields.tucse = 0;
188 	TXD->upper_setup.tcp_fields.tucso =
189 	    pi->ipi_ehdrlen + pi->ipi_ip_hlen + offsetof(struct tcphdr, th_sum);
190 
191 	/*
192 	 * Payload size per packet w/o any headers.
193 	 * Length of all headers up to payload.
194 	 */
195 	TXD->tcp_seg_setup.fields.mss = htole16(pi->ipi_tso_segsz);
196 	TXD->tcp_seg_setup.fields.hdr_len = hdr_len;
197 
198 	/*
199 	 * "PCI/PCI-X SDM 4.0" page 45, and "PCIe GbE SDM 2.5" page 63
200 	 * - Set up basic TUCMDs
201 	 * - For others IP bit on indicates IPv4, while off indicates IPv6
202 	*/
203 	cmd_type_len = sc->txd_cmd |
204 	    E1000_TXD_CMD_DEXT | /* Extended descr */
205 	    E1000_TXD_CMD_TSE |  /* TSE context */
206 	    E1000_TXD_CMD_TCP;   /* Do TCP checksum */
207 	if (pi->ipi_etype == ETHERTYPE_IP)
208 		cmd_type_len |= E1000_TXD_CMD_IP;
209 	TXD->cmd_and_length = htole32(cmd_type_len |
210 	    (pi->ipi_len - hdr_len)); /* Total len */
211 
212 	txr->tx_tso = true;
213 
214 	if (++cur == scctx->isc_ntxd[0]) {
215 		cur = 0;
216 	}
217 	DPRINTF(iflib_get_dev(sc->ctx), "%s: pidx: %d cur: %d\n", __FUNCTION__,
218 	    pi->ipi_pidx, cur);
219 	return (cur);
220 }
221 
222 /*********************************************************************
223  *  The offload context is protocol specific (TCP/UDP) and thus
224  *  only needs to be set when the protocol changes. The occasion
225  *  of a context change can be a performance detriment, and
226  *  might be better just disabled. The reason arises in the way
227  *  in which the controller supports pipelined requests from the
228  *  Tx data DMA. Up to four requests can be pipelined, and they may
229  *  belong to the same packet or to multiple packets. However all
230  *  requests for one packet are issued before a request is issued
231  *  for a subsequent packet and if a request for the next packet
232  *  requires a context change, that request will be stalled
233  *  until the previous request completes. This means setting up
234  *  a new context effectively disables pipelined Tx data DMA which
235  *  in turn greatly slow down performance to send small sized
236  *  frames.
237  **********************************************************************/
238 #define DONT_FORCE_CTX 1
239 
240 static int
241 em_transmit_checksum_setup(struct e1000_softc *sc, if_pkt_info_t pi,
242     uint32_t *txd_upper, uint32_t *txd_lower)
243 {
244 	struct e1000_context_desc *TXD = NULL;
245 	if_softc_ctx_t scctx = sc->shared;
246 	struct em_tx_queue *que = &sc->tx_queues[pi->ipi_qsidx];
247 	struct tx_ring *txr = &que->txr;
248 	int csum_flags = pi->ipi_csum_flags;
249 	int cur, hdr_len;
250 	uint32_t cmd;
251 
252 	cur = pi->ipi_pidx;
253 	hdr_len = pi->ipi_ehdrlen + pi->ipi_ip_hlen;
254 	cmd = sc->txd_cmd;
255 
256 	/*
257 	 * The 82574L can only remember the *last* context used
258 	 * regardless of queue that it was use for.  We cannot reuse
259 	 * contexts on this hardware platform and must generate a new
260 	 * context every time.  82574L hardware spec, section 7.2.6,
261 	 * second note.
262 	 */
263 	if (DONT_FORCE_CTX &&
264 	    sc->tx_num_queues == 1 &&
265 	    txr->csum_lhlen == pi->ipi_ehdrlen &&
266 	    txr->csum_iphlen == pi->ipi_ip_hlen &&
267 	    txr->csum_flags == csum_flags) {
268 		/*
269 		 * Same csum offload context as the previous packets;
270 		 * just return.
271 		 */
272 		*txd_upper = txr->csum_txd_upper;
273 		*txd_lower = txr->csum_txd_lower;
274 		return (cur);
275 	}
276 
277 	TXD = (struct e1000_context_desc *)&txr->tx_base[cur];
278 	/*
279 	 * ipcss - Start offset for header checksum calculation.
280 	 * ipcse - End offset for header checksum calculation.
281 	 * ipcso - Offset of place to put the checksum.
282 	 *
283 	 * We set ipcsX values regardless of IP version to work around HW issues
284 	 * and ipcse must be 0 for IPv6 per "PCIe GbE SDM 2.5" page 61.
285 	 * IXSM controls whether it's inserted.
286 	 */
287 	TXD->lower_setup.ip_fields.ipcss = pi->ipi_ehdrlen;
288 	TXD->lower_setup.ip_fields.ipcso = pi->ipi_ehdrlen +
289 	    offsetof(struct ip, ip_sum);
290 	if (csum_flags & CSUM_IP) {
291 		*txd_upper |= E1000_TXD_POPTS_IXSM << 8;
292 		TXD->lower_setup.ip_fields.ipcse = htole16(hdr_len - 1);
293 		cmd |= E1000_TXD_CMD_IP;
294 	} else if (csum_flags & (CSUM_IP6_TCP | CSUM_IP6_UDP))
295 		TXD->lower_setup.ip_fields.ipcse = htole16(0);
296 
297 	/*
298 	 * tucss - Start offset for payload checksum calculation.
299 	 * tucse - End offset for payload checksum calculation.
300 	 * tucso - Offset of place to put the checksum.
301 	 */
302 	if (csum_flags & (CSUM_TCP | CSUM_UDP | CSUM_IP6_TCP | CSUM_IP6_UDP)) {
303 		uint8_t tucso;
304 
305 		*txd_upper |= E1000_TXD_POPTS_TXSM << 8;
306 		*txd_lower = E1000_TXD_CMD_DEXT | E1000_TXD_DTYP_D;
307 
308 		if (csum_flags & (CSUM_TCP | CSUM_IP6_TCP)) {
309 			tucso = hdr_len + offsetof(struct tcphdr, th_sum);
310 			cmd |= E1000_TXD_CMD_TCP;
311 		} else
312 			tucso = hdr_len + offsetof(struct udphdr, uh_sum);
313 		TXD->upper_setup.tcp_fields.tucss = hdr_len;
314 		TXD->upper_setup.tcp_fields.tucse = htole16(0);
315 		TXD->upper_setup.tcp_fields.tucso = tucso;
316 	}
317 
318 	txr->csum_lhlen = pi->ipi_ehdrlen;
319 	txr->csum_iphlen = pi->ipi_ip_hlen;
320 	txr->csum_flags = csum_flags;
321 	txr->csum_txd_upper = *txd_upper;
322 	txr->csum_txd_lower = *txd_lower;
323 
324 	TXD->tcp_seg_setup.data = htole32(0);
325 	TXD->cmd_and_length =
326 		htole32(E1000_TXD_CMD_IFCS | E1000_TXD_CMD_DEXT | cmd);
327 
328 	if (++cur == scctx->isc_ntxd[0]) {
329 		cur = 0;
330 	}
331 	DPRINTF(iflib_get_dev(sc->ctx),
332 	    "checksum_setup csum_flags=%x txd_upper=%x txd_lower=%x hdr_len=%d cmd=%x\n",
333 	    csum_flags, *txd_upper, *txd_lower, hdr_len, cmd);
334 	return (cur);
335 }
336 
337 #define TSO_WORKAROUND 4 /* TSO sentinel descriptor */
338 
339 static int
340 em_isc_txd_encap(void *arg, if_pkt_info_t pi)
341 {
342 	struct e1000_softc *sc = arg;
343 	if_softc_ctx_t scctx = sc->shared;
344 	struct em_tx_queue *que = &sc->tx_queues[pi->ipi_qsidx];
345 	struct tx_ring *txr = &que->txr;
346 	bus_dma_segment_t *segs = pi->ipi_segs;
347 	int nsegs = pi->ipi_nsegs;
348 	int csum_flags = pi->ipi_csum_flags;
349 	int i, j, first, pidx_last;
350 	uint32_t txd_flags, txd_upper = 0, txd_lower = 0;
351 
352 	struct e1000_tx_desc *ctxd = NULL;
353 	bool do_tso, tso_desc;
354 	qidx_t ntxd;
355 
356 	txd_flags = pi->ipi_flags & IPI_TX_INTR ? E1000_TXD_CMD_RS : 0;
357 	i = first = pi->ipi_pidx;
358 	do_tso = (csum_flags & CSUM_TSO);
359 	tso_desc = false;
360 	ntxd = scctx->isc_ntxd[0];
361 	/*
362 	 * TSO Hardware workaround, if this packet is not
363 	 * TSO, and is only a single descriptor long, and
364 	 * it follows a TSO burst, then we need to add a
365 	 * sentinel descriptor to prevent premature writeback.
366 	 */
367 	if ((!do_tso) && (txr->tx_tso == true)) {
368 		if (nsegs == 1)
369 			tso_desc = true;
370 		txr->tx_tso = false;
371 	}
372 
373 	/* Do hardware assists */
374 	if (do_tso) {
375 		i = em_tso_setup(sc, pi, &txd_upper, &txd_lower);
376 		tso_desc = true;
377 	} else if (csum_flags & EM_CSUM_OFFLOAD) {
378 		i = em_transmit_checksum_setup(sc, pi, &txd_upper, &txd_lower);
379 	}
380 
381 	if (pi->ipi_mflags & M_VLANTAG) {
382 		/* Set the vlan id. */
383 		txd_upper |= htole16(pi->ipi_vtag) << 16;
384 		/* Tell hardware to add tag */
385 		txd_lower |= htole32(E1000_TXD_CMD_VLE);
386 	}
387 
388 	DPRINTF(iflib_get_dev(sc->ctx),
389 	    "encap: set up tx: nsegs=%d first=%d i=%d\n", nsegs, first, i);
390 	/* XXX sc->pcix_82544 -- lem_fill_descriptors */
391 
392 	/* Set up our transmit descriptors */
393 	for (j = 0; j < nsegs; j++) {
394 		bus_size_t seg_len;
395 		bus_addr_t seg_addr;
396 		uint32_t cmd;
397 
398 		ctxd = &txr->tx_base[i];
399 		seg_addr = segs[j].ds_addr;
400 		seg_len = segs[j].ds_len;
401 		cmd = E1000_TXD_CMD_IFCS | sc->txd_cmd;
402 
403 		/*
404 		 * TSO Workaround:
405 		 * If this is the last descriptor, we want to
406 		 * split it so we have a small final sentinel
407 		 */
408 		if (tso_desc && (j == (nsegs - 1)) && (seg_len > 8)) {
409 			seg_len -= TSO_WORKAROUND;
410 			ctxd->buffer_addr = htole64(seg_addr);
411 			ctxd->lower.data = htole32(cmd | txd_lower | seg_len);
412 			ctxd->upper.data = htole32(txd_upper);
413 
414 			if (++i == scctx->isc_ntxd[0])
415 				i = 0;
416 
417 			/* Now make the sentinel */
418 			ctxd = &txr->tx_base[i];
419 			ctxd->buffer_addr = htole64(seg_addr + seg_len);
420 			ctxd->lower.data = htole32(cmd | txd_lower | TSO_WORKAROUND);
421 			ctxd->upper.data = htole32(txd_upper);
422 			pidx_last = i;
423 			if (++i == scctx->isc_ntxd[0])
424 				i = 0;
425 			DPRINTF(iflib_get_dev(sc->ctx),
426 			    "TSO path pidx_last=%d i=%d ntxd[0]=%d\n",
427 			    pidx_last, i, scctx->isc_ntxd[0]);
428 		} else {
429 			ctxd->buffer_addr = htole64(seg_addr);
430 			ctxd->lower.data = htole32(cmd | txd_lower | seg_len);
431 			ctxd->upper.data = htole32(txd_upper);
432 			pidx_last = i;
433 			if (++i == scctx->isc_ntxd[0])
434 				i = 0;
435 			DPRINTF(iflib_get_dev(sc->ctx), "pidx_last=%d i=%d ntxd[0]=%d\n",
436 			    pidx_last, i, scctx->isc_ntxd[0]);
437 		}
438 	}
439 
440 	/*
441 	 * Last Descriptor of Packet
442 	 * needs End Of Packet (EOP)
443 	 * and Report Status (RS)
444 	 */
445 	if (txd_flags && nsegs) {
446 		txr->tx_rsq[txr->tx_rs_pidx] = pidx_last;
447 		DPRINTF(iflib_get_dev(sc->ctx),
448 		    "setting to RS on %d rs_pidx %d first: %d\n",
449 		    pidx_last, txr->tx_rs_pidx, first);
450 		txr->tx_rs_pidx = (txr->tx_rs_pidx+1) & (ntxd-1);
451 		MPASS(txr->tx_rs_pidx != txr->tx_rs_cidx);
452 	}
453 	ctxd->lower.data |= htole32(E1000_TXD_CMD_EOP | txd_flags);
454 	DPRINTF(iflib_get_dev(sc->ctx),
455 	    "tx_buffers[%d]->eop = %d ipi_new_pidx=%d\n", first, pidx_last, i);
456 	pi->ipi_new_pidx = i;
457 
458 	return (0);
459 }
460 
461 static void
462 em_isc_txd_flush(void *arg, uint16_t txqid, qidx_t pidx)
463 {
464 	struct e1000_softc *sc = arg;
465 	struct em_tx_queue *que = &sc->tx_queues[txqid];
466 	struct tx_ring *txr = &que->txr;
467 
468 	E1000_WRITE_REG(&sc->hw, E1000_TDT(txr->me), pidx);
469 }
470 
471 static int
472 em_isc_txd_credits_update(void *arg, uint16_t txqid, bool clear)
473 {
474 	struct e1000_softc *sc = arg;
475 	if_softc_ctx_t scctx = sc->shared;
476 	struct em_tx_queue *que = &sc->tx_queues[txqid];
477 	struct tx_ring *txr = &que->txr;
478 
479 	qidx_t processed = 0;
480 	int updated;
481 	qidx_t cur, prev, ntxd, rs_cidx;
482 	int32_t delta;
483 	uint8_t status;
484 
485 	rs_cidx = txr->tx_rs_cidx;
486 	if (rs_cidx == txr->tx_rs_pidx)
487 		return (0);
488 	cur = txr->tx_rsq[rs_cidx];
489 	MPASS(cur != QIDX_INVALID);
490 	status = txr->tx_base[cur].upper.fields.status;
491 	updated = !!(status & E1000_TXD_STAT_DD);
492 
493 	if (!updated)
494 		return (0);
495 
496 	/* If clear is false just let caller know that there
497 	 * are descriptors to reclaim */
498 	if (!clear)
499 		return (1);
500 
501 	prev = txr->tx_cidx_processed;
502 	ntxd = scctx->isc_ntxd[0];
503 	do {
504 		MPASS(prev != cur);
505 		delta = (int32_t)cur - (int32_t)prev;
506 		if (delta < 0)
507 			delta += ntxd;
508 		MPASS(delta > 0);
509 		DPRINTF(iflib_get_dev(sc->ctx),
510 			      "%s: cidx_processed=%u cur=%u clear=%d delta=%d\n",
511 			      __FUNCTION__, prev, cur, clear, delta);
512 
513 		processed += delta;
514 		prev  = cur;
515 		rs_cidx = (rs_cidx + 1) & (ntxd-1);
516 		if (rs_cidx  == txr->tx_rs_pidx)
517 			break;
518 		cur = txr->tx_rsq[rs_cidx];
519 		MPASS(cur != QIDX_INVALID);
520 		status = txr->tx_base[cur].upper.fields.status;
521 	} while ((status & E1000_TXD_STAT_DD));
522 
523 	txr->tx_rs_cidx = rs_cidx;
524 	txr->tx_cidx_processed = prev;
525 	return(processed);
526 }
527 
528 static void
529 lem_isc_rxd_refill(void *arg, if_rxd_update_t iru)
530 {
531 	struct e1000_softc *sc = arg;
532 	if_softc_ctx_t scctx = sc->shared;
533 	struct em_rx_queue *que = &sc->rx_queues[iru->iru_qsidx];
534 	struct rx_ring *rxr = &que->rxr;
535 	struct e1000_rx_desc *rxd;
536 	uint64_t *paddrs;
537 	uint32_t next_pidx, pidx;
538 	uint16_t count;
539 	int i;
540 
541 	paddrs = iru->iru_paddrs;
542 	pidx = iru->iru_pidx;
543 	count = iru->iru_count;
544 
545 	for (i = 0, next_pidx = pidx; i < count; i++) {
546 		rxd = (struct e1000_rx_desc *)&rxr->rx_base[next_pidx];
547 		rxd->buffer_addr = htole64(paddrs[i]);
548 		/* status bits must be cleared */
549 		rxd->status = 0;
550 
551 		if (++next_pidx == scctx->isc_nrxd[0])
552 			next_pidx = 0;
553 	}
554 }
555 
556 static void
557 em_isc_rxd_refill(void *arg, if_rxd_update_t iru)
558 {
559 	struct e1000_softc *sc = arg;
560 	if_softc_ctx_t scctx = sc->shared;
561 	uint16_t rxqid = iru->iru_qsidx;
562 	struct em_rx_queue *que = &sc->rx_queues[rxqid];
563 	struct rx_ring *rxr = &que->rxr;
564 	union e1000_rx_desc_extended *rxd;
565 	uint64_t *paddrs;
566 	uint32_t next_pidx, pidx;
567 	uint16_t count;
568 	int i;
569 
570 	paddrs = iru->iru_paddrs;
571 	pidx = iru->iru_pidx;
572 	count = iru->iru_count;
573 
574 	for (i = 0, next_pidx = pidx; i < count; i++) {
575 		rxd = &rxr->rx_base[next_pidx];
576 		rxd->read.buffer_addr = htole64(paddrs[i]);
577 		/* DD bits must be cleared */
578 		rxd->wb.upper.status_error = 0;
579 
580 		if (++next_pidx == scctx->isc_nrxd[0])
581 			next_pidx = 0;
582 	}
583 }
584 
585 static void
586 em_isc_rxd_flush(void *arg, uint16_t rxqid, uint8_t flid __unused,
587     qidx_t pidx)
588 {
589 	struct e1000_softc *sc = arg;
590 	struct em_rx_queue *que = &sc->rx_queues[rxqid];
591 	struct rx_ring *rxr = &que->rxr;
592 
593 	E1000_WRITE_REG(&sc->hw, E1000_RDT(rxr->me), pidx);
594 }
595 
596 static int
597 lem_isc_rxd_available(void *arg, uint16_t rxqid, qidx_t idx, qidx_t budget)
598 {
599 	struct e1000_softc *sc = arg;
600 	if_softc_ctx_t scctx = sc->shared;
601 	struct em_rx_queue *que = &sc->rx_queues[rxqid];
602 	struct rx_ring *rxr = &que->rxr;
603 	struct e1000_rx_desc *rxd;
604 	uint32_t staterr = 0;
605 	int cnt, i;
606 
607 	for (cnt = 0, i = idx; cnt < scctx->isc_nrxd[0] && cnt <= budget;) {
608 		rxd = (struct e1000_rx_desc *)&rxr->rx_base[i];
609 		staterr = rxd->status;
610 
611 		if ((staterr & E1000_RXD_STAT_DD) == 0)
612 			break;
613 		if (++i == scctx->isc_nrxd[0])
614 			i = 0;
615 		if (staterr & E1000_RXD_STAT_EOP)
616 			cnt++;
617 	}
618 	return (cnt);
619 }
620 
621 static int
622 em_isc_rxd_available(void *arg, uint16_t rxqid, qidx_t idx, qidx_t budget)
623 {
624 	struct e1000_softc *sc = arg;
625 	if_softc_ctx_t scctx = sc->shared;
626 	struct em_rx_queue *que = &sc->rx_queues[rxqid];
627 	struct rx_ring *rxr = &que->rxr;
628 	union e1000_rx_desc_extended *rxd;
629 	uint32_t staterr = 0;
630 	int cnt, i;
631 
632 	for (cnt = 0, i = idx; cnt < scctx->isc_nrxd[0] && cnt <= budget;) {
633 		rxd = &rxr->rx_base[i];
634 		staterr = le32toh(rxd->wb.upper.status_error);
635 
636 		if ((staterr & E1000_RXD_STAT_DD) == 0)
637 			break;
638 		if (++i == scctx->isc_nrxd[0])
639 			i = 0;
640 		if (staterr & E1000_RXD_STAT_EOP)
641 			cnt++;
642 	}
643 	return (cnt);
644 }
645 
646 static int
647 lem_isc_rxd_pkt_get(void *arg, if_rxd_info_t ri)
648 {
649 	struct e1000_softc *sc = arg;
650 	if_softc_ctx_t scctx = sc->shared;
651 	struct em_rx_queue *que = &sc->rx_queues[ri->iri_qsidx];
652 	struct rx_ring *rxr = &que->rxr;
653 	struct e1000_rx_desc *rxd;
654 	uint16_t len;
655 	uint32_t status, errors;
656 	bool eop;
657 	int i, cidx;
658 
659 	status = errors = i = 0;
660 	cidx = ri->iri_cidx;
661 
662 	do {
663 		rxd = (struct e1000_rx_desc *)&rxr->rx_base[cidx];
664 		status = rxd->status;
665 		errors = rxd->errors;
666 
667 		/* Error Checking then decrement count */
668 		MPASS ((status & E1000_RXD_STAT_DD) != 0);
669 
670 		len = le16toh(rxd->length);
671 		ri->iri_len += len;
672 
673 		eop = (status & E1000_RXD_STAT_EOP) != 0;
674 
675 		/* Make sure bad packets are discarded */
676 		if (errors & E1000_RXD_ERR_FRAME_ERR_MASK) {
677 			sc->dropped_pkts++;
678 			/* XXX fixup if common */
679 			return (EBADMSG);
680 		}
681 
682 		ri->iri_frags[i].irf_flid = 0;
683 		ri->iri_frags[i].irf_idx = cidx;
684 		ri->iri_frags[i].irf_len = len;
685 		/* Zero out the receive descriptors status. */
686 		rxd->status = 0;
687 
688 		if (++cidx == scctx->isc_nrxd[0])
689 			cidx = 0;
690 		i++;
691 	} while (!eop);
692 
693 	if (scctx->isc_capenable & IFCAP_RXCSUM)
694 		em_receive_checksum(status, errors, ri);
695 
696 	if (scctx->isc_capenable & IFCAP_VLAN_HWTAGGING &&
697 	    status & E1000_RXD_STAT_VP) {
698 		ri->iri_vtag = le16toh(rxd->special & E1000_RXD_SPC_VLAN_MASK);
699 		ri->iri_flags |= M_VLANTAG;
700 	}
701 
702 	ri->iri_nfrags = i;
703 
704 	return (0);
705 }
706 
707 static int
708 em_isc_rxd_pkt_get(void *arg, if_rxd_info_t ri)
709 {
710 	struct e1000_softc *sc = arg;
711 	if_softc_ctx_t scctx = sc->shared;
712 	struct em_rx_queue *que = &sc->rx_queues[ri->iri_qsidx];
713 	struct rx_ring *rxr = &que->rxr;
714 	union e1000_rx_desc_extended *rxd;
715 
716 	uint16_t len;
717 	uint32_t pkt_info;
718 	uint32_t staterr;
719 	bool eop;
720 	int i, cidx;
721 
722 	staterr = i = 0;
723 	cidx = ri->iri_cidx;
724 
725 	do {
726 		rxd = &rxr->rx_base[cidx];
727 		staterr = le32toh(rxd->wb.upper.status_error);
728 		pkt_info = le32toh(rxd->wb.lower.mrq);
729 
730 		/* Error Checking then decrement count */
731 		MPASS ((staterr & E1000_RXD_STAT_DD) != 0);
732 
733 		len = le16toh(rxd->wb.upper.length);
734 		ri->iri_len += len;
735 
736 		eop = (staterr & E1000_RXD_STAT_EOP) != 0;
737 
738 		/* Make sure bad packets are discarded */
739 		if (staterr & E1000_RXDEXT_ERR_FRAME_ERR_MASK) {
740 			sc->dropped_pkts++;
741 			return EBADMSG;
742 		}
743 
744 		ri->iri_frags[i].irf_flid = 0;
745 		ri->iri_frags[i].irf_idx = cidx;
746 		ri->iri_frags[i].irf_len = len;
747 		/* Zero out the receive descriptors status. */
748 		rxd->wb.upper.status_error &= htole32(~0xFF);
749 
750 		if (++cidx == scctx->isc_nrxd[0])
751 			cidx = 0;
752 		i++;
753 	} while (!eop);
754 
755 	if (scctx->isc_capenable & IFCAP_RXCSUM)
756 		em_receive_checksum(staterr, staterr >> 24, ri);
757 
758 	if (scctx->isc_capenable & IFCAP_VLAN_HWTAGGING &&
759 	    staterr & E1000_RXD_STAT_VP) {
760 		ri->iri_vtag = le16toh(rxd->wb.upper.vlan);
761 		ri->iri_flags |= M_VLANTAG;
762 	}
763 
764 	ri->iri_flowid = le32toh(rxd->wb.lower.hi_dword.rss);
765 	ri->iri_rsstype = em_determine_rsstype(pkt_info);
766 
767 	ri->iri_nfrags = i;
768 	return (0);
769 }
770 
771 /*********************************************************************
772  *
773  *  Verify that the hardware indicated that the checksum is valid.
774  *  Inform the stack about the status of checksum so that stack
775  *  doesn't spend time verifying the checksum.
776  *
777  *********************************************************************/
778 static void
779 em_receive_checksum(uint16_t status, uint8_t errors, if_rxd_info_t ri)
780 {
781 	if (__predict_false(status & E1000_RXD_STAT_IXSM))
782 		return;
783 
784 	/* If there is a layer 3 or 4 error we are done */
785 	if (__predict_false(errors & (E1000_RXD_ERR_IPE | E1000_RXD_ERR_TCPE)))
786 		return;
787 
788 	/* IP Checksum Good */
789 	if (status & E1000_RXD_STAT_IPCS)
790 		ri->iri_csum_flags = (CSUM_IP_CHECKED | CSUM_IP_VALID);
791 
792 	/* Valid L4E checksum */
793 	if (__predict_true(status &
794 	    (E1000_RXD_STAT_TCPCS | E1000_RXD_STAT_UDPCS))) {
795 		ri->iri_csum_flags |= CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
796 		ri->iri_csum_data = htons(0xffff);
797 	}
798 }
799 
800 /********************************************************************
801  *
802  *  Parse the packet type to determine the appropriate hash
803  *
804  ******************************************************************/
805 static int
806 em_determine_rsstype(uint32_t pkt_info)
807 {
808 	switch (pkt_info & E1000_RXDADV_RSSTYPE_MASK) {
809 	case E1000_RXDADV_RSSTYPE_IPV4_TCP:
810 		return M_HASHTYPE_RSS_TCP_IPV4;
811 	case E1000_RXDADV_RSSTYPE_IPV4:
812 		return M_HASHTYPE_RSS_IPV4;
813 	case E1000_RXDADV_RSSTYPE_IPV6_TCP:
814 		return M_HASHTYPE_RSS_TCP_IPV6;
815 	case E1000_RXDADV_RSSTYPE_IPV6_EX:
816 		return M_HASHTYPE_RSS_IPV6_EX;
817 	case E1000_RXDADV_RSSTYPE_IPV6:
818 		return M_HASHTYPE_RSS_IPV6;
819 	case E1000_RXDADV_RSSTYPE_IPV6_TCP_EX:
820 		return M_HASHTYPE_RSS_TCP_IPV6_EX;
821 	default:
822 		return M_HASHTYPE_OPAQUE;
823 	}
824 }
825