1 /*
2 * Copyright (C) 2011-2014 Matteo Landi, Luigi Rizzo. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 /*
27 * $FreeBSD$
28 *
29 * netmap support for: ixgbe (both ix and ixv)
30 *
31 * This file is meant to be a reference on how to implement
32 * netmap support for a network driver.
33 * This file contains code but only static or inline functions used
34 * by a single driver. To avoid replication of code we just #include
35 * it near the beginning of the standard driver.
36 */
37
38
39 #include <net/netmap.h>
40 #include <sys/selinfo.h>
41 /*
42 * Some drivers may need the following headers. Others
43 * already include them by default
44
45 #include <vm/vm.h>
46 #include <vm/pmap.h>
47
48 */
49 #include <dev/netmap/netmap_kern.h>
50
51 void ixgbe_netmap_attach(struct adapter *adapter);
52
53 /*
54 * device-specific sysctl variables:
55 *
56 * ix_crcstrip: 0: keep CRC in rx frames (default), 1: strip it.
57 * During regular operations the CRC is stripped, but on some
58 * hardware reception of frames not multiple of 64 is slower,
59 * so using crcstrip=0 helps in benchmarks.
60 *
61 * ix_rx_miss, ix_rx_miss_bufs:
62 * count packets that might be missed due to lost interrupts.
63 */
64 SYSCTL_DECL(_dev_netmap);
65 static int ix_rx_miss, ix_rx_miss_bufs;
66 int ix_crcstrip;
67 SYSCTL_INT(_dev_netmap, OID_AUTO, ix_crcstrip,
68 CTLFLAG_RW, &ix_crcstrip, 0, "strip CRC on rx frames");
69 SYSCTL_INT(_dev_netmap, OID_AUTO, ix_rx_miss,
70 CTLFLAG_RW, &ix_rx_miss, 0, "potentially missed rx intr");
71 SYSCTL_INT(_dev_netmap, OID_AUTO, ix_rx_miss_bufs,
72 CTLFLAG_RW, &ix_rx_miss_bufs, 0, "potentially missed rx intr bufs");
73
74
75 static void
set_crcstrip(struct ixgbe_hw * hw,int onoff)76 set_crcstrip(struct ixgbe_hw *hw, int onoff)
77 {
78 /* crc stripping is set in two places:
79 * IXGBE_HLREG0 (modified on init_locked and hw reset)
80 * IXGBE_RDRXCTL (set by the original driver in
81 * ixgbe_setup_hw_rsc() called in init_locked.
82 * We disable the setting when netmap is compiled in).
83 * We update the values here, but also in ixgbe.c because
84 * init_locked sometimes is called outside our control.
85 */
86 uint32_t hl, rxc;
87
88 hl = IXGBE_READ_REG(hw, IXGBE_HLREG0);
89 rxc = IXGBE_READ_REG(hw, IXGBE_RDRXCTL);
90 if (netmap_verbose)
91 D("%s read HLREG 0x%x rxc 0x%x",
92 onoff ? "enter" : "exit", hl, rxc);
93 /* hw requirements ... */
94 rxc &= ~IXGBE_RDRXCTL_RSCFRSTSIZE;
95 rxc |= IXGBE_RDRXCTL_RSCACKC;
96 if (onoff && !ix_crcstrip) {
97 /* keep the crc. Fast rx */
98 hl &= ~IXGBE_HLREG0_RXCRCSTRP;
99 rxc &= ~IXGBE_RDRXCTL_CRCSTRIP;
100 } else {
101 /* reset default mode */
102 hl |= IXGBE_HLREG0_RXCRCSTRP;
103 rxc |= IXGBE_RDRXCTL_CRCSTRIP;
104 }
105 if (netmap_verbose)
106 D("%s write HLREG 0x%x rxc 0x%x",
107 onoff ? "enter" : "exit", hl, rxc);
108 IXGBE_WRITE_REG(hw, IXGBE_HLREG0, hl);
109 IXGBE_WRITE_REG(hw, IXGBE_RDRXCTL, rxc);
110 }
111
112
113 /*
114 * Register/unregister. We are already under netmap lock.
115 * Only called on the first register or the last unregister.
116 */
117 static int
ixgbe_netmap_reg(struct netmap_adapter * na,int onoff)118 ixgbe_netmap_reg(struct netmap_adapter *na, int onoff)
119 {
120 struct ifnet *ifp = na->ifp;
121 struct adapter *adapter = ifp->if_softc;
122
123 IXGBE_CORE_LOCK(adapter);
124 adapter->stop_locked(adapter);
125
126 if (!IXGBE_IS_VF(adapter))
127 set_crcstrip(&adapter->hw, onoff);
128 /* enable or disable flags and callbacks in na and ifp */
129 if (onoff) {
130 nm_set_native_flags(na);
131 } else {
132 nm_clear_native_flags(na);
133 }
134 adapter->init_locked(adapter); /* also enables intr */
135 if (!IXGBE_IS_VF(adapter))
136 set_crcstrip(&adapter->hw, onoff); // XXX why twice ?
137 IXGBE_CORE_UNLOCK(adapter);
138 return (ifp->if_drv_flags & IFF_DRV_RUNNING ? 0 : 1);
139 }
140
141
142 /*
143 * Reconcile kernel and user view of the transmit ring.
144 *
145 * All information is in the kring.
146 * Userspace wants to send packets up to the one before kring->rhead,
147 * kernel knows kring->nr_hwcur is the first unsent packet.
148 *
149 * Here we push packets out (as many as possible), and possibly
150 * reclaim buffers from previously completed transmission.
151 *
152 * The caller (netmap) guarantees that there is only one instance
153 * running at any time. Any interference with other driver
154 * methods should be handled by the individual drivers.
155 */
156 static int
ixgbe_netmap_txsync(struct netmap_kring * kring,int flags)157 ixgbe_netmap_txsync(struct netmap_kring *kring, int flags)
158 {
159 struct netmap_adapter *na = kring->na;
160 struct ifnet *ifp = na->ifp;
161 struct netmap_ring *ring = kring->ring;
162 u_int nm_i; /* index into the netmap ring */
163 u_int nic_i; /* index into the NIC ring */
164 u_int n;
165 u_int const lim = kring->nkr_num_slots - 1;
166 u_int const head = kring->rhead;
167 /*
168 * interrupts on every tx packet are expensive so request
169 * them every half ring, or where NS_REPORT is set
170 */
171 u_int report_frequency = kring->nkr_num_slots >> 1;
172
173 /* device-specific */
174 struct adapter *adapter = ifp->if_softc;
175 struct tx_ring *txr = &adapter->tx_rings[kring->ring_id];
176 int reclaim_tx;
177
178 bus_dmamap_sync(txr->txdma.dma_tag, txr->txdma.dma_map,
179 BUS_DMASYNC_POSTREAD);
180
181 /*
182 * First part: process new packets to send.
183 * nm_i is the current index in the netmap ring,
184 * nic_i is the corresponding index in the NIC ring.
185 * The two numbers differ because upon a *_init() we reset
186 * the NIC ring but leave the netmap ring unchanged.
187 * For the transmit ring, we have
188 *
189 * nm_i = kring->nr_hwcur
190 * nic_i = IXGBE_TDT (not tracked in the driver)
191 * and
192 * nm_i == (nic_i + kring->nkr_hwofs) % ring_size
193 *
194 * In this driver kring->nkr_hwofs >= 0, but for other
195 * drivers it might be negative as well.
196 */
197
198 /*
199 * If we have packets to send (kring->nr_hwcur != kring->rhead)
200 * iterate over the netmap ring, fetch length and update
201 * the corresponding slot in the NIC ring. Some drivers also
202 * need to update the buffer's physical address in the NIC slot
203 * even NS_BUF_CHANGED is not set (PNMB computes the addresses).
204 *
205 * The netmap_reload_map() calls is especially expensive,
206 * even when (as in this case) the tag is 0, so do only
207 * when the buffer has actually changed.
208 *
209 * If possible do not set the report/intr bit on all slots,
210 * but only a few times per ring or when NS_REPORT is set.
211 *
212 * Finally, on 10G and faster drivers, it might be useful
213 * to prefetch the next slot and txr entry.
214 */
215
216 nm_i = kring->nr_hwcur;
217 if (nm_i != head) { /* we have new packets to send */
218 nic_i = netmap_idx_k2n(kring, nm_i);
219
220 __builtin_prefetch(&ring->slot[nm_i]);
221 __builtin_prefetch(&txr->tx_buffers[nic_i]);
222
223 for (n = 0; nm_i != head; n++) {
224 struct netmap_slot *slot = &ring->slot[nm_i];
225 u_int len = slot->len;
226 uint64_t paddr;
227 void *addr = PNMB(na, slot, &paddr);
228
229 /* device-specific */
230 union ixgbe_adv_tx_desc *curr = &txr->tx_base[nic_i];
231 struct ixgbe_tx_buf *txbuf = &txr->tx_buffers[nic_i];
232 int flags = (slot->flags & NS_REPORT ||
233 nic_i == 0 || nic_i == report_frequency) ?
234 IXGBE_TXD_CMD_RS : 0;
235
236 /* prefetch for next round */
237 __builtin_prefetch(&ring->slot[nm_i + 1]);
238 __builtin_prefetch(&txr->tx_buffers[nic_i + 1]);
239
240 NM_CHECK_ADDR_LEN(na, addr, len);
241
242 if (slot->flags & NS_BUF_CHANGED) {
243 /* buffer has changed, reload map */
244 netmap_reload_map(na, txr->txtag, txbuf->map, addr);
245 }
246 slot->flags &= ~(NS_REPORT | NS_BUF_CHANGED);
247
248 /* Fill the slot in the NIC ring. */
249 /* Use legacy descriptor, they are faster? */
250 curr->read.buffer_addr = htole64(paddr);
251 curr->read.olinfo_status = 0;
252 curr->read.cmd_type_len = htole32(len | flags |
253 IXGBE_ADVTXD_DCMD_IFCS | IXGBE_TXD_CMD_EOP);
254
255 /* make sure changes to the buffer are synced */
256 bus_dmamap_sync(txr->txtag, txbuf->map,
257 BUS_DMASYNC_PREWRITE);
258
259 nm_i = nm_next(nm_i, lim);
260 nic_i = nm_next(nic_i, lim);
261 }
262 kring->nr_hwcur = head;
263
264 /* synchronize the NIC ring */
265 bus_dmamap_sync(txr->txdma.dma_tag, txr->txdma.dma_map,
266 BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
267
268 /* (re)start the tx unit up to slot nic_i (excluded) */
269 IXGBE_WRITE_REG(&adapter->hw, txr->tail, nic_i);
270 }
271
272 /*
273 * Second part: reclaim buffers for completed transmissions.
274 * Because this is expensive (we read a NIC register etc.)
275 * we only do it in specific cases (see below).
276 */
277 if (flags & NAF_FORCE_RECLAIM) {
278 reclaim_tx = 1; /* forced reclaim */
279 } else if (!nm_kr_txempty(kring)) {
280 reclaim_tx = 0; /* have buffers, no reclaim */
281 } else {
282 /*
283 * No buffers available. Locate previous slot with
284 * REPORT_STATUS set.
285 * If the slot has DD set, we can reclaim space,
286 * otherwise wait for the next interrupt.
287 * This enables interrupt moderation on the tx
288 * side though it might reduce throughput.
289 */
290 struct ixgbe_legacy_tx_desc *txd =
291 (struct ixgbe_legacy_tx_desc *)txr->tx_base;
292
293 nic_i = txr->next_to_clean + report_frequency;
294 if (nic_i > lim)
295 nic_i -= lim + 1;
296 // round to the closest with dd set
297 nic_i = (nic_i < kring->nkr_num_slots / 4 ||
298 nic_i >= kring->nkr_num_slots*3/4) ?
299 0 : report_frequency;
300 reclaim_tx = txd[nic_i].upper.fields.status & IXGBE_TXD_STAT_DD; // XXX cpu_to_le32 ?
301 }
302 if (reclaim_tx) {
303 /*
304 * Record completed transmissions.
305 * We (re)use the driver's txr->next_to_clean to keep
306 * track of the most recently completed transmission.
307 *
308 * The datasheet discourages the use of TDH to find
309 * out the number of sent packets, but we only set
310 * REPORT_STATUS in a few slots so TDH is the only
311 * good way.
312 */
313 nic_i = IXGBE_READ_REG(&adapter->hw, IXGBE_IS_VF(adapter) ?
314 IXGBE_VFTDH(kring->ring_id) : IXGBE_TDH(kring->ring_id));
315 if (nic_i >= kring->nkr_num_slots) { /* XXX can it happen ? */
316 D("TDH wrap %d", nic_i);
317 nic_i -= kring->nkr_num_slots;
318 }
319 if (nic_i != txr->next_to_clean) {
320 /* some tx completed, increment avail */
321 txr->next_to_clean = nic_i;
322 kring->nr_hwtail = nm_prev(netmap_idx_n2k(kring, nic_i), lim);
323 }
324 }
325
326 return 0;
327 }
328
329
330 /*
331 * Reconcile kernel and user view of the receive ring.
332 * Same as for the txsync, this routine must be efficient.
333 * The caller guarantees a single invocations, but races against
334 * the rest of the driver should be handled here.
335 *
336 * On call, kring->rhead is the first packet that userspace wants
337 * to keep, and kring->rcur is the wakeup point.
338 * The kernel has previously reported packets up to kring->rtail.
339 *
340 * If (flags & NAF_FORCE_READ) also check for incoming packets irrespective
341 * of whether or not we received an interrupt.
342 */
343 static int
ixgbe_netmap_rxsync(struct netmap_kring * kring,int flags)344 ixgbe_netmap_rxsync(struct netmap_kring *kring, int flags)
345 {
346 struct netmap_adapter *na = kring->na;
347 struct ifnet *ifp = na->ifp;
348 struct netmap_ring *ring = kring->ring;
349 u_int nm_i; /* index into the netmap ring */
350 u_int nic_i; /* index into the NIC ring */
351 u_int n;
352 u_int const lim = kring->nkr_num_slots - 1;
353 u_int const head = kring->rhead;
354 int force_update = (flags & NAF_FORCE_READ) || kring->nr_kflags & NKR_PENDINTR;
355
356 /* device-specific */
357 struct adapter *adapter = ifp->if_softc;
358 struct rx_ring *rxr = &adapter->rx_rings[kring->ring_id];
359
360 if (head > lim)
361 return netmap_ring_reinit(kring);
362
363 /* XXX check sync modes */
364 bus_dmamap_sync(rxr->rxdma.dma_tag, rxr->rxdma.dma_map,
365 BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
366
367 /*
368 * First part: import newly received packets.
369 *
370 * nm_i is the index of the next free slot in the netmap ring,
371 * nic_i is the index of the next received packet in the NIC ring,
372 * and they may differ in case if_init() has been called while
373 * in netmap mode. For the receive ring we have
374 *
375 * nic_i = rxr->next_to_check;
376 * nm_i = kring->nr_hwtail (previous)
377 * and
378 * nm_i == (nic_i + kring->nkr_hwofs) % ring_size
379 *
380 * rxr->next_to_check is set to 0 on a ring reinit
381 */
382 if (netmap_no_pendintr || force_update) {
383 int crclen = (ix_crcstrip || IXGBE_IS_VF(adapter) ) ? 0 : 4;
384 uint16_t slot_flags = kring->nkr_slot_flags;
385
386 nic_i = rxr->next_to_check; // or also k2n(kring->nr_hwtail)
387 nm_i = netmap_idx_n2k(kring, nic_i);
388
389 for (n = 0; ; n++) {
390 union ixgbe_adv_rx_desc *curr = &rxr->rx_base[nic_i];
391 uint32_t staterr = le32toh(curr->wb.upper.status_error);
392
393 if ((staterr & IXGBE_RXD_STAT_DD) == 0)
394 break;
395 ring->slot[nm_i].len = le16toh(curr->wb.upper.length) - crclen;
396 ring->slot[nm_i].flags = slot_flags;
397 bus_dmamap_sync(rxr->ptag,
398 rxr->rx_buffers[nic_i].pmap, BUS_DMASYNC_POSTREAD);
399 nm_i = nm_next(nm_i, lim);
400 nic_i = nm_next(nic_i, lim);
401 }
402 if (n) { /* update the state variables */
403 if (netmap_no_pendintr && !force_update) {
404 /* diagnostics */
405 ix_rx_miss ++;
406 ix_rx_miss_bufs += n;
407 }
408 rxr->next_to_check = nic_i;
409 kring->nr_hwtail = nm_i;
410 }
411 kring->nr_kflags &= ~NKR_PENDINTR;
412 }
413
414 /*
415 * Second part: skip past packets that userspace has released.
416 * (kring->nr_hwcur to kring->rhead excluded),
417 * and make the buffers available for reception.
418 * As usual nm_i is the index in the netmap ring,
419 * nic_i is the index in the NIC ring, and
420 * nm_i == (nic_i + kring->nkr_hwofs) % ring_size
421 */
422 nm_i = kring->nr_hwcur;
423 if (nm_i != head) {
424 nic_i = netmap_idx_k2n(kring, nm_i);
425 for (n = 0; nm_i != head; n++) {
426 struct netmap_slot *slot = &ring->slot[nm_i];
427 uint64_t paddr;
428 void *addr = PNMB(na, slot, &paddr);
429
430 union ixgbe_adv_rx_desc *curr = &rxr->rx_base[nic_i];
431 struct ixgbe_rx_buf *rxbuf = &rxr->rx_buffers[nic_i];
432
433 if (addr == NETMAP_BUF_BASE(na)) /* bad buf */
434 goto ring_reset;
435
436 if (slot->flags & NS_BUF_CHANGED) {
437 /* buffer has changed, reload map */
438 netmap_reload_map(na, rxr->ptag, rxbuf->pmap, addr);
439 slot->flags &= ~NS_BUF_CHANGED;
440 }
441 curr->wb.upper.status_error = 0;
442 curr->read.pkt_addr = htole64(paddr);
443 bus_dmamap_sync(rxr->ptag, rxbuf->pmap,
444 BUS_DMASYNC_PREREAD);
445 nm_i = nm_next(nm_i, lim);
446 nic_i = nm_next(nic_i, lim);
447 }
448 kring->nr_hwcur = head;
449
450 bus_dmamap_sync(rxr->rxdma.dma_tag, rxr->rxdma.dma_map,
451 BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
452 /*
453 * IMPORTANT: we must leave one free slot in the ring,
454 * so move nic_i back by one unit
455 */
456 nic_i = nm_prev(nic_i, lim);
457 IXGBE_WRITE_REG(&adapter->hw, rxr->tail, nic_i);
458 }
459
460 return 0;
461
462 ring_reset:
463 return netmap_ring_reinit(kring);
464 }
465
466
467 /*
468 * The attach routine, called near the end of ixgbe_attach(),
469 * fills the parameters for netmap_attach() and calls it.
470 * It cannot fail, in the worst case (such as no memory)
471 * netmap mode will be disabled and the driver will only
472 * operate in standard mode.
473 */
474 void
ixgbe_netmap_attach(struct adapter * adapter)475 ixgbe_netmap_attach(struct adapter *adapter)
476 {
477 struct netmap_adapter na;
478
479 bzero(&na, sizeof(na));
480
481 na.ifp = adapter->ifp;
482 na.na_flags = NAF_BDG_MAYSLEEP;
483 na.num_tx_desc = adapter->num_tx_desc;
484 na.num_rx_desc = adapter->num_rx_desc;
485 na.nm_txsync = ixgbe_netmap_txsync;
486 na.nm_rxsync = ixgbe_netmap_rxsync;
487 na.nm_register = ixgbe_netmap_reg;
488 na.num_tx_rings = na.num_rx_rings = adapter->num_queues;
489 netmap_attach(&na);
490 }
491
492 /* end of file */
493