Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/dev/netmap/ixgbe_netmap.h
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1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (C) 2011-2014 Matteo Landi, Luigi Rizzo. All rights reserved. 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 /* 29 * $FreeBSD: releng/12.0/sys/dev/netmap/ixgbe_netmap.h 332319 2018-04-09 09:24:26Z vmaffione $ 30 * 31 * netmap support for: ixgbe (both ix and ixv) 32 * 33 * This file is meant to be a reference on how to implement 34 * netmap support for a network driver. 35 * This file contains code but only static or inline functions used 36 * by a single driver. To avoid replication of code we just #include 37 * it near the beginning of the standard driver. 38 */ 39 40 41 #include <net/netmap.h> 42 #include <sys/selinfo.h> 43 /* 44 * Some drivers may need the following headers. Others 45 * already include them by default 46 47 #include <vm/vm.h> 48 #include <vm/pmap.h> 49 50 */ 51 #include <dev/netmap/netmap_kern.h> 52 53 void ixgbe_netmap_attach(struct adapter *adapter); 54 55 /* 56 * device-specific sysctl variables: 57 * 58 * ix_crcstrip: 0: NIC keeps CRC in rx frames (default), 1: NIC strips it. 59 * During regular operations the CRC is stripped, but on some 60 * hardware reception of frames not multiple of 64 is slower, 61 * so using crcstrip=0 helps in benchmarks. 62 * 63 * ix_rx_miss, ix_rx_miss_bufs: 64 * count packets that might be missed due to lost interrupts. 65 */ 66 SYSCTL_DECL(_dev_netmap); 67 static int ix_rx_miss, ix_rx_miss_bufs; 68 int ix_crcstrip; 69 SYSCTL_INT(_dev_netmap, OID_AUTO, ix_crcstrip, 70 CTLFLAG_RW, &ix_crcstrip, 0, "NIC strips CRC on rx frames"); 71 SYSCTL_INT(_dev_netmap, OID_AUTO, ix_rx_miss, 72 CTLFLAG_RW, &ix_rx_miss, 0, "potentially missed rx intr"); 73 SYSCTL_INT(_dev_netmap, OID_AUTO, ix_rx_miss_bufs, 74 CTLFLAG_RW, &ix_rx_miss_bufs, 0, "potentially missed rx intr bufs"); 75 76 77 static void 78 set_crcstrip(struct ixgbe_hw *hw, int onoff) 79 { 80 /* crc stripping is set in two places: 81 * IXGBE_HLREG0 (modified on init_locked and hw reset) 82 * IXGBE_RDRXCTL (set by the original driver in 83 * ixgbe_setup_hw_rsc() called in init_locked. 84 * We disable the setting when netmap is compiled in). 85 * We update the values here, but also in ixgbe.c because 86 * init_locked sometimes is called outside our control. 87 */ 88 uint32_t hl, rxc; 89 90 hl = IXGBE_READ_REG(hw, IXGBE_HLREG0); 91 rxc = IXGBE_READ_REG(hw, IXGBE_RDRXCTL); 92 if (netmap_verbose) 93 D("%s read HLREG 0x%x rxc 0x%x", 94 onoff ? "enter" : "exit", hl, rxc); 95 /* hw requirements ... */ 96 rxc &= ~IXGBE_RDRXCTL_RSCFRSTSIZE; 97 rxc |= IXGBE_RDRXCTL_RSCACKC; 98 if (onoff && !ix_crcstrip) { 99 /* keep the crc. Fast rx */ 100 hl &= ~IXGBE_HLREG0_RXCRCSTRP; 101 rxc &= ~IXGBE_RDRXCTL_CRCSTRIP; 102 } else { 103 /* reset default mode */ 104 hl |= IXGBE_HLREG0_RXCRCSTRP; 105 rxc |= IXGBE_RDRXCTL_CRCSTRIP; 106 } 107 if (netmap_verbose) 108 D("%s write HLREG 0x%x rxc 0x%x", 109 onoff ? "enter" : "exit", hl, rxc); 110 IXGBE_WRITE_REG(hw, IXGBE_HLREG0, hl); 111 IXGBE_WRITE_REG(hw, IXGBE_RDRXCTL, rxc); 112 } 113 114 static void 115 ixgbe_netmap_intr(struct netmap_adapter *na, int onoff) 116 { 117 struct ifnet *ifp = na->ifp; 118 struct adapter *adapter = ifp->if_softc; 119 120 IXGBE_CORE_LOCK(adapter); 121 if (onoff) { 122 ixgbe_enable_intr(adapter); // XXX maybe ixgbe_stop ? 123 } else { 124 ixgbe_disable_intr(adapter); // XXX maybe ixgbe_stop ? 125 } 126 IXGBE_CORE_UNLOCK(adapter); 127 } 128 129 /* 130 * Register/unregister. We are already under netmap lock. 131 * Only called on the first register or the last unregister. 132 */ 133 static int 134 ixgbe_netmap_reg(struct netmap_adapter *na, int onoff) 135 { 136 struct ifnet *ifp = na->ifp; 137 struct adapter *adapter = ifp->if_softc; 138 139 IXGBE_CORE_LOCK(adapter); 140 adapter->stop_locked(adapter); 141 142 if (!IXGBE_IS_VF(adapter)) 143 set_crcstrip(&adapter->hw, onoff); 144 /* enable or disable flags and callbacks in na and ifp */ 145 if (onoff) { 146 nm_set_native_flags(na); 147 } else { 148 nm_clear_native_flags(na); 149 } 150 adapter->init_locked(adapter); /* also enables intr */ 151 if (!IXGBE_IS_VF(adapter)) 152 set_crcstrip(&adapter->hw, onoff); // XXX why twice ? 153 IXGBE_CORE_UNLOCK(adapter); 154 return (ifp->if_drv_flags & IFF_DRV_RUNNING ? 0 : 1); 155 } 156 157 158 /* 159 * Reconcile kernel and user view of the transmit ring. 160 * 161 * All information is in the kring. 162 * Userspace wants to send packets up to the one before kring->rhead, 163 * kernel knows kring->nr_hwcur is the first unsent packet. 164 * 165 * Here we push packets out (as many as possible), and possibly 166 * reclaim buffers from previously completed transmission. 167 * 168 * The caller (netmap) guarantees that there is only one instance 169 * running at any time. Any interference with other driver 170 * methods should be handled by the individual drivers. 171 */ 172 static int 173 ixgbe_netmap_txsync(struct netmap_kring *kring, int flags) 174 { 175 struct netmap_adapter *na = kring->na; 176 struct ifnet *ifp = na->ifp; 177 struct netmap_ring *ring = kring->ring; 178 u_int nm_i; /* index into the netmap ring */ 179 u_int nic_i; /* index into the NIC ring */ 180 u_int n; 181 u_int const lim = kring->nkr_num_slots - 1; 182 u_int const head = kring->rhead; 183 /* 184 * interrupts on every tx packet are expensive so request 185 * them every half ring, or where NS_REPORT is set 186 */ 187 u_int report_frequency = kring->nkr_num_slots >> 1; 188 189 /* device-specific */ 190 struct adapter *adapter = ifp->if_softc; 191 struct tx_ring *txr = &adapter->tx_rings[kring->ring_id]; 192 int reclaim_tx; 193 194 bus_dmamap_sync(txr->txdma.dma_tag, txr->txdma.dma_map, 195 BUS_DMASYNC_POSTREAD); 196 197 /* 198 * First part: process new packets to send. 199 * nm_i is the current index in the netmap ring, 200 * nic_i is the corresponding index in the NIC ring. 201 * The two numbers differ because upon a *_init() we reset 202 * the NIC ring but leave the netmap ring unchanged. 203 * For the transmit ring, we have 204 * 205 * nm_i = kring->nr_hwcur 206 * nic_i = IXGBE_TDT (not tracked in the driver) 207 * and 208 * nm_i == (nic_i + kring->nkr_hwofs) % ring_size 209 * 210 * In this driver kring->nkr_hwofs >= 0, but for other 211 * drivers it might be negative as well. 212 */ 213 214 /* 215 * If we have packets to send (kring->nr_hwcur != kring->rhead) 216 * iterate over the netmap ring, fetch length and update 217 * the corresponding slot in the NIC ring. Some drivers also 218 * need to update the buffer's physical address in the NIC slot 219 * even NS_BUF_CHANGED is not set (PNMB computes the addresses). 220 * 221 * The netmap_reload_map() calls is especially expensive, 222 * even when (as in this case) the tag is 0, so do only 223 * when the buffer has actually changed. 224 * 225 * If possible do not set the report/intr bit on all slots, 226 * but only a few times per ring or when NS_REPORT is set. 227 * 228 * Finally, on 10G and faster drivers, it might be useful 229 * to prefetch the next slot and txr entry. 230 */ 231 232 nm_i = kring->nr_hwcur; 233 if (nm_i != head) { /* we have new packets to send */ 234 nic_i = netmap_idx_k2n(kring, nm_i); 235 236 __builtin_prefetch(&ring->slot[nm_i]); 237 __builtin_prefetch(&txr->tx_buffers[nic_i]); 238 239 for (n = 0; nm_i != head; n++) { 240 struct netmap_slot *slot = &ring->slot[nm_i]; 241 u_int len = slot->len; 242 uint64_t paddr; 243 void *addr = PNMB(na, slot, &paddr); 244 245 /* device-specific */ 246 union ixgbe_adv_tx_desc *curr = &txr->tx_base[nic_i]; 247 struct ixgbe_tx_buf *txbuf = &txr->tx_buffers[nic_i]; 248 int flags = (slot->flags & NS_REPORT || 249 nic_i == 0 || nic_i == report_frequency) ? 250 IXGBE_TXD_CMD_RS : 0; 251 252 /* prefetch for next round */ 253 __builtin_prefetch(&ring->slot[nm_i + 1]); 254 __builtin_prefetch(&txr->tx_buffers[nic_i + 1]); 255 256 NM_CHECK_ADDR_LEN(na, addr, len); 257 258 if (slot->flags & NS_BUF_CHANGED) { 259 /* buffer has changed, reload map */ 260 netmap_reload_map(na, txr->txtag, txbuf->map, addr); 261 } 262 slot->flags &= ~(NS_REPORT | NS_BUF_CHANGED); 263 264 /* Fill the slot in the NIC ring. */ 265 /* Use legacy descriptor, they are faster? */ 266 curr->read.buffer_addr = htole64(paddr); 267 curr->read.olinfo_status = 0; 268 curr->read.cmd_type_len = htole32(len | flags | 269 IXGBE_ADVTXD_DCMD_IFCS | IXGBE_TXD_CMD_EOP); 270 271 /* make sure changes to the buffer are synced */ 272 bus_dmamap_sync(txr->txtag, txbuf->map, 273 BUS_DMASYNC_PREWRITE); 274 275 nm_i = nm_next(nm_i, lim); 276 nic_i = nm_next(nic_i, lim); 277 } 278 kring->nr_hwcur = head; 279 280 /* synchronize the NIC ring */ 281 bus_dmamap_sync(txr->txdma.dma_tag, txr->txdma.dma_map, 282 BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE); 283 284 /* (re)start the tx unit up to slot nic_i (excluded) */ 285 IXGBE_WRITE_REG(&adapter->hw, txr->tail, nic_i); 286 } 287 288 /* 289 * Second part: reclaim buffers for completed transmissions. 290 * Because this is expensive (we read a NIC register etc.) 291 * we only do it in specific cases (see below). 292 */ 293 if (flags & NAF_FORCE_RECLAIM) { 294 reclaim_tx = 1; /* forced reclaim */ 295 } else if (!nm_kr_txempty(kring)) { 296 reclaim_tx = 0; /* have buffers, no reclaim */ 297 } else { 298 /* 299 * No buffers available. Locate previous slot with 300 * REPORT_STATUS set. 301 * If the slot has DD set, we can reclaim space, 302 * otherwise wait for the next interrupt. 303 * This enables interrupt moderation on the tx 304 * side though it might reduce throughput. 305 */ 306 struct ixgbe_legacy_tx_desc *txd = 307 (struct ixgbe_legacy_tx_desc *)txr->tx_base; 308 309 nic_i = txr->next_to_clean + report_frequency; 310 if (nic_i > lim) 311 nic_i -= lim + 1; 312 // round to the closest with dd set 313 nic_i = (nic_i < kring->nkr_num_slots / 4 || 314 nic_i >= kring->nkr_num_slots*3/4) ? 315 0 : report_frequency; 316 reclaim_tx = txd[nic_i].upper.fields.status & IXGBE_TXD_STAT_DD; // XXX cpu_to_le32 ? 317 } 318 if (reclaim_tx) { 319 /* 320 * Record completed transmissions. 321 * We (re)use the driver's txr->next_to_clean to keep 322 * track of the most recently completed transmission. 323 * 324 * The datasheet discourages the use of TDH to find 325 * out the number of sent packets, but we only set 326 * REPORT_STATUS in a few slots so TDH is the only 327 * good way. 328 */ 329 nic_i = IXGBE_READ_REG(&adapter->hw, IXGBE_IS_VF(adapter) ? 330 IXGBE_VFTDH(kring->ring_id) : IXGBE_TDH(kring->ring_id)); 331 if (nic_i >= kring->nkr_num_slots) { /* XXX can it happen ? */ 332 D("TDH wrap %d", nic_i); 333 nic_i -= kring->nkr_num_slots; 334 } 335 if (nic_i != txr->next_to_clean) { 336 /* some tx completed, increment avail */ 337 txr->next_to_clean = nic_i; 338 kring->nr_hwtail = nm_prev(netmap_idx_n2k(kring, nic_i), lim); 339 } 340 } 341 342 return 0; 343 } 344 345 346 /* 347 * Reconcile kernel and user view of the receive ring. 348 * Same as for the txsync, this routine must be efficient. 349 * The caller guarantees a single invocations, but races against 350 * the rest of the driver should be handled here. 351 * 352 * On call, kring->rhead is the first packet that userspace wants 353 * to keep, and kring->rcur is the wakeup point. 354 * The kernel has previously reported packets up to kring->rtail. 355 * 356 * If (flags & NAF_FORCE_READ) also check for incoming packets irrespective 357 * of whether or not we received an interrupt. 358 */ 359 static int 360 ixgbe_netmap_rxsync(struct netmap_kring *kring, int flags) 361 { 362 struct netmap_adapter *na = kring->na; 363 struct ifnet *ifp = na->ifp; 364 struct netmap_ring *ring = kring->ring; 365 u_int nm_i; /* index into the netmap ring */ 366 u_int nic_i; /* index into the NIC ring */ 367 u_int n; 368 u_int const lim = kring->nkr_num_slots - 1; 369 u_int const head = kring->rhead; 370 int force_update = (flags & NAF_FORCE_READ) || kring->nr_kflags & NKR_PENDINTR; 371 372 /* device-specific */ 373 struct adapter *adapter = ifp->if_softc; 374 struct rx_ring *rxr = &adapter->rx_rings[kring->ring_id]; 375 376 if (head > lim) 377 return netmap_ring_reinit(kring); 378 379 /* XXX check sync modes */ 380 bus_dmamap_sync(rxr->rxdma.dma_tag, rxr->rxdma.dma_map, 381 BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE); 382 383 /* 384 * First part: import newly received packets. 385 * 386 * nm_i is the index of the next free slot in the netmap ring, 387 * nic_i is the index of the next received packet in the NIC ring, 388 * and they may differ in case if_init() has been called while 389 * in netmap mode. For the receive ring we have 390 * 391 * nic_i = rxr->next_to_check; 392 * nm_i = kring->nr_hwtail (previous) 393 * and 394 * nm_i == (nic_i + kring->nkr_hwofs) % ring_size 395 * 396 * rxr->next_to_check is set to 0 on a ring reinit 397 */ 398 if (netmap_no_pendintr || force_update) { 399 int crclen = (ix_crcstrip || IXGBE_IS_VF(adapter) ) ? 0 : 4; 400 401 nic_i = rxr->next_to_check; // or also k2n(kring->nr_hwtail) 402 nm_i = netmap_idx_n2k(kring, nic_i); 403 404 for (n = 0; ; n++) { 405 union ixgbe_adv_rx_desc *curr = &rxr->rx_base[nic_i]; 406 uint32_t staterr = le32toh(curr->wb.upper.status_error); 407 408 if ((staterr & IXGBE_RXD_STAT_DD) == 0) 409 break; 410 ring->slot[nm_i].len = le16toh(curr->wb.upper.length) - crclen; 411 ring->slot[nm_i].flags = 0; 412 bus_dmamap_sync(rxr->ptag, 413 rxr->rx_buffers[nic_i].pmap, BUS_DMASYNC_POSTREAD); 414 nm_i = nm_next(nm_i, lim); 415 nic_i = nm_next(nic_i, lim); 416 } 417 if (n) { /* update the state variables */ 418 if (netmap_no_pendintr && !force_update) { 419 /* diagnostics */ 420 ix_rx_miss ++; 421 ix_rx_miss_bufs += n; 422 } 423 rxr->next_to_check = nic_i; 424 kring->nr_hwtail = nm_i; 425 } 426 kring->nr_kflags &= ~NKR_PENDINTR; 427 } 428 429 /* 430 * Second part: skip past packets that userspace has released. 431 * (kring->nr_hwcur to kring->rhead excluded), 432 * and make the buffers available for reception. 433 * As usual nm_i is the index in the netmap ring, 434 * nic_i is the index in the NIC ring, and 435 * nm_i == (nic_i + kring->nkr_hwofs) % ring_size 436 */ 437 nm_i = kring->nr_hwcur; 438 if (nm_i != head) { 439 nic_i = netmap_idx_k2n(kring, nm_i); 440 for (n = 0; nm_i != head; n++) { 441 struct netmap_slot *slot = &ring->slot[nm_i]; 442 uint64_t paddr; 443 void *addr = PNMB(na, slot, &paddr); 444 445 union ixgbe_adv_rx_desc *curr = &rxr->rx_base[nic_i]; 446 struct ixgbe_rx_buf *rxbuf = &rxr->rx_buffers[nic_i]; 447 448 if (addr == NETMAP_BUF_BASE(na)) /* bad buf */ 449 goto ring_reset; 450 451 if (slot->flags & NS_BUF_CHANGED) { 452 /* buffer has changed, reload map */ 453 netmap_reload_map(na, rxr->ptag, rxbuf->pmap, addr); 454 slot->flags &= ~NS_BUF_CHANGED; 455 } 456 curr->wb.upper.status_error = 0; 457 curr->read.pkt_addr = htole64(paddr); 458 bus_dmamap_sync(rxr->ptag, rxbuf->pmap, 459 BUS_DMASYNC_PREREAD); 460 nm_i = nm_next(nm_i, lim); 461 nic_i = nm_next(nic_i, lim); 462 } 463 kring->nr_hwcur = head; 464 465 bus_dmamap_sync(rxr->rxdma.dma_tag, rxr->rxdma.dma_map, 466 BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE); 467 /* 468 * IMPORTANT: we must leave one free slot in the ring, 469 * so move nic_i back by one unit 470 */ 471 nic_i = nm_prev(nic_i, lim); 472 IXGBE_WRITE_REG(&adapter->hw, rxr->tail, nic_i); 473 } 474 475 return 0; 476 477 ring_reset: 478 return netmap_ring_reinit(kring); 479 } 480 481 482 /* 483 * The attach routine, called near the end of ixgbe_attach(), 484 * fills the parameters for netmap_attach() and calls it. 485 * It cannot fail, in the worst case (such as no memory) 486 * netmap mode will be disabled and the driver will only 487 * operate in standard mode. 488 */ 489 void 490 ixgbe_netmap_attach(struct adapter *adapter) 491 { 492 struct netmap_adapter na; 493 494 bzero(&na, sizeof(na)); 495 496 na.ifp = adapter->ifp; 497 na.na_flags = NAF_BDG_MAYSLEEP; 498 na.num_tx_desc = adapter->num_tx_desc; 499 na.num_rx_desc = adapter->num_rx_desc; 500 na.nm_txsync = ixgbe_netmap_txsync; 501 na.nm_rxsync = ixgbe_netmap_rxsync; 502 na.nm_register = ixgbe_netmap_reg; 503 na.num_tx_rings = na.num_rx_rings = adapter->num_queues; 504 na.nm_intr = ixgbe_netmap_intr; 505 netmap_attach(&na); 506 } 507 508 /* end of file */
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