1 // SPDX-License-Identifier: GPL-2.0-only 2 /**************************************************************************** 3 * Driver for Solarflare network controllers and boards 4 * Copyright 2018 Solarflare Communications Inc. 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 as published 8 * by the Free Software Foundation, incorporated herein by reference. 9 */ 10 11 #include "net_driver.h" 12 #include "efx.h" 13 #include "nic_common.h" 14 #include "tx_common.h" 15 #include <net/gso.h> 16 17 static unsigned int efx_tx_cb_page_count(struct efx_tx_queue *tx_queue) 18 { 19 return DIV_ROUND_UP(tx_queue->ptr_mask + 1, 20 PAGE_SIZE >> EFX_TX_CB_ORDER); 21 } 22 23 int efx_probe_tx_queue(struct efx_tx_queue *tx_queue) 24 { 25 struct efx_nic *efx = tx_queue->efx; 26 unsigned int entries; 27 int rc; 28 29 /* Create the smallest power-of-two aligned ring */ 30 entries = max(roundup_pow_of_two(efx->txq_entries), EFX_MIN_DMAQ_SIZE); 31 EFX_WARN_ON_PARANOID(entries > EFX_MAX_DMAQ_SIZE); 32 tx_queue->ptr_mask = entries - 1; 33 34 netif_dbg(efx, probe, efx->net_dev, 35 "creating TX queue %d size %#x mask %#x\n", 36 tx_queue->queue, efx->txq_entries, tx_queue->ptr_mask); 37 38 /* Allocate software ring */ 39 tx_queue->buffer = kcalloc(entries, sizeof(*tx_queue->buffer), 40 GFP_KERNEL); 41 if (!tx_queue->buffer) 42 return -ENOMEM; 43 44 tx_queue->cb_page = kcalloc(efx_tx_cb_page_count(tx_queue), 45 sizeof(tx_queue->cb_page[0]), GFP_KERNEL); 46 if (!tx_queue->cb_page) { 47 rc = -ENOMEM; 48 goto fail1; 49 } 50 51 /* Allocate hardware ring, determine TXQ type */ 52 rc = efx_nic_probe_tx(tx_queue); 53 if (rc) 54 goto fail2; 55 56 tx_queue->channel->tx_queue_by_type[tx_queue->type] = tx_queue; 57 return 0; 58 59 fail2: 60 kfree(tx_queue->cb_page); 61 tx_queue->cb_page = NULL; 62 fail1: 63 kfree(tx_queue->buffer); 64 tx_queue->buffer = NULL; 65 return rc; 66 } 67 68 void efx_init_tx_queue(struct efx_tx_queue *tx_queue) 69 { 70 struct efx_nic *efx = tx_queue->efx; 71 72 netif_dbg(efx, drv, efx->net_dev, 73 "initialising TX queue %d\n", tx_queue->queue); 74 75 tx_queue->insert_count = 0; 76 tx_queue->notify_count = 0; 77 tx_queue->write_count = 0; 78 tx_queue->packet_write_count = 0; 79 tx_queue->old_write_count = 0; 80 tx_queue->read_count = 0; 81 tx_queue->old_read_count = 0; 82 tx_queue->empty_read_count = 0 | EFX_EMPTY_COUNT_VALID; 83 tx_queue->xmit_pending = false; 84 tx_queue->timestamping = (efx_ptp_use_mac_tx_timestamps(efx) && 85 tx_queue->channel == efx_ptp_channel(efx)); 86 tx_queue->completed_timestamp_major = 0; 87 tx_queue->completed_timestamp_minor = 0; 88 89 tx_queue->xdp_tx = efx_channel_is_xdp_tx(tx_queue->channel); 90 tx_queue->tso_version = 0; 91 92 /* Set up TX descriptor ring */ 93 efx_nic_init_tx(tx_queue); 94 95 tx_queue->initialised = true; 96 } 97 98 void efx_fini_tx_queue(struct efx_tx_queue *tx_queue) 99 { 100 struct efx_tx_buffer *buffer; 101 102 netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev, 103 "shutting down TX queue %d\n", tx_queue->queue); 104 105 tx_queue->initialised = false; 106 107 if (!tx_queue->buffer) 108 return; 109 110 /* Free any buffers left in the ring */ 111 while (tx_queue->read_count != tx_queue->write_count) { 112 unsigned int pkts_compl = 0, bytes_compl = 0; 113 unsigned int efv_pkts_compl = 0; 114 115 buffer = &tx_queue->buffer[tx_queue->read_count & tx_queue->ptr_mask]; 116 efx_dequeue_buffer(tx_queue, buffer, &pkts_compl, &bytes_compl, 117 &efv_pkts_compl); 118 119 ++tx_queue->read_count; 120 } 121 tx_queue->xmit_pending = false; 122 netdev_tx_reset_queue(tx_queue->core_txq); 123 } 124 125 void efx_remove_tx_queue(struct efx_tx_queue *tx_queue) 126 { 127 int i; 128 129 if (!tx_queue->buffer) 130 return; 131 132 netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev, 133 "destroying TX queue %d\n", tx_queue->queue); 134 efx_nic_remove_tx(tx_queue); 135 136 if (tx_queue->cb_page) { 137 for (i = 0; i < efx_tx_cb_page_count(tx_queue); i++) 138 efx_nic_free_buffer(tx_queue->efx, 139 &tx_queue->cb_page[i]); 140 kfree(tx_queue->cb_page); 141 tx_queue->cb_page = NULL; 142 } 143 144 kfree(tx_queue->buffer); 145 tx_queue->buffer = NULL; 146 tx_queue->channel->tx_queue_by_type[tx_queue->type] = NULL; 147 } 148 149 void efx_dequeue_buffer(struct efx_tx_queue *tx_queue, 150 struct efx_tx_buffer *buffer, 151 unsigned int *pkts_compl, 152 unsigned int *bytes_compl, 153 unsigned int *efv_pkts_compl) 154 { 155 if (buffer->unmap_len) { 156 struct device *dma_dev = &tx_queue->efx->pci_dev->dev; 157 dma_addr_t unmap_addr = buffer->dma_addr - buffer->dma_offset; 158 159 if (buffer->flags & EFX_TX_BUF_MAP_SINGLE) 160 dma_unmap_single(dma_dev, unmap_addr, buffer->unmap_len, 161 DMA_TO_DEVICE); 162 else 163 dma_unmap_page(dma_dev, unmap_addr, buffer->unmap_len, 164 DMA_TO_DEVICE); 165 buffer->unmap_len = 0; 166 } 167 168 if (buffer->flags & EFX_TX_BUF_SKB) { 169 struct sk_buff *skb = (struct sk_buff *)buffer->skb; 170 171 if (unlikely(buffer->flags & EFX_TX_BUF_EFV)) { 172 EFX_WARN_ON_PARANOID(!efv_pkts_compl); 173 (*efv_pkts_compl)++; 174 } else { 175 EFX_WARN_ON_PARANOID(!pkts_compl || !bytes_compl); 176 (*pkts_compl)++; 177 (*bytes_compl) += skb->len; 178 } 179 180 if (tx_queue->timestamping && 181 (tx_queue->completed_timestamp_major || 182 tx_queue->completed_timestamp_minor)) { 183 struct skb_shared_hwtstamps hwtstamp; 184 185 hwtstamp.hwtstamp = 186 efx_ptp_nic_to_kernel_time(tx_queue); 187 skb_tstamp_tx(skb, &hwtstamp); 188 189 tx_queue->completed_timestamp_major = 0; 190 tx_queue->completed_timestamp_minor = 0; 191 } 192 dev_consume_skb_any((struct sk_buff *)buffer->skb); 193 netif_vdbg(tx_queue->efx, tx_done, tx_queue->efx->net_dev, 194 "TX queue %d transmission id %x complete\n", 195 tx_queue->queue, tx_queue->read_count); 196 } else if (buffer->flags & EFX_TX_BUF_XDP) { 197 xdp_return_frame_rx_napi(buffer->xdpf); 198 } 199 200 buffer->len = 0; 201 buffer->flags = 0; 202 } 203 204 /* Remove packets from the TX queue 205 * 206 * This removes packets from the TX queue, up to and including the 207 * specified index. 208 */ 209 static void efx_dequeue_buffers(struct efx_tx_queue *tx_queue, 210 unsigned int index, 211 unsigned int *pkts_compl, 212 unsigned int *bytes_compl, 213 unsigned int *efv_pkts_compl) 214 { 215 struct efx_nic *efx = tx_queue->efx; 216 unsigned int stop_index, read_ptr; 217 218 stop_index = (index + 1) & tx_queue->ptr_mask; 219 read_ptr = tx_queue->read_count & tx_queue->ptr_mask; 220 221 while (read_ptr != stop_index) { 222 struct efx_tx_buffer *buffer = &tx_queue->buffer[read_ptr]; 223 224 if (!efx_tx_buffer_in_use(buffer)) { 225 netif_err(efx, tx_err, efx->net_dev, 226 "TX queue %d spurious TX completion id %d\n", 227 tx_queue->queue, read_ptr); 228 efx_schedule_reset(efx, RESET_TYPE_TX_SKIP); 229 return; 230 } 231 232 efx_dequeue_buffer(tx_queue, buffer, pkts_compl, bytes_compl, 233 efv_pkts_compl); 234 235 ++tx_queue->read_count; 236 read_ptr = tx_queue->read_count & tx_queue->ptr_mask; 237 } 238 } 239 240 void efx_xmit_done_check_empty(struct efx_tx_queue *tx_queue) 241 { 242 if ((int)(tx_queue->read_count - tx_queue->old_write_count) >= 0) { 243 tx_queue->old_write_count = READ_ONCE(tx_queue->write_count); 244 if (tx_queue->read_count == tx_queue->old_write_count) { 245 /* Ensure that read_count is flushed. */ 246 smp_mb(); 247 tx_queue->empty_read_count = 248 tx_queue->read_count | EFX_EMPTY_COUNT_VALID; 249 } 250 } 251 } 252 253 int efx_xmit_done(struct efx_tx_queue *tx_queue, unsigned int index) 254 { 255 unsigned int fill_level, pkts_compl = 0, bytes_compl = 0; 256 unsigned int efv_pkts_compl = 0; 257 struct efx_nic *efx = tx_queue->efx; 258 259 EFX_WARN_ON_ONCE_PARANOID(index > tx_queue->ptr_mask); 260 261 efx_dequeue_buffers(tx_queue, index, &pkts_compl, &bytes_compl, 262 &efv_pkts_compl); 263 tx_queue->pkts_compl += pkts_compl; 264 tx_queue->bytes_compl += bytes_compl; 265 266 if (pkts_compl + efv_pkts_compl > 1) 267 ++tx_queue->merge_events; 268 269 /* See if we need to restart the netif queue. This memory 270 * barrier ensures that we write read_count (inside 271 * efx_dequeue_buffers()) before reading the queue status. 272 */ 273 smp_mb(); 274 if (unlikely(netif_tx_queue_stopped(tx_queue->core_txq)) && 275 likely(efx->port_enabled) && 276 likely(netif_device_present(efx->net_dev))) { 277 fill_level = efx_channel_tx_fill_level(tx_queue->channel); 278 if (fill_level <= efx->txq_wake_thresh) 279 netif_tx_wake_queue(tx_queue->core_txq); 280 } 281 282 efx_xmit_done_check_empty(tx_queue); 283 284 return pkts_compl + efv_pkts_compl; 285 } 286 287 /* Remove buffers put into a tx_queue for the current packet. 288 * None of the buffers must have an skb attached. 289 */ 290 void efx_enqueue_unwind(struct efx_tx_queue *tx_queue, 291 unsigned int insert_count) 292 { 293 unsigned int efv_pkts_compl = 0; 294 struct efx_tx_buffer *buffer; 295 unsigned int bytes_compl = 0; 296 unsigned int pkts_compl = 0; 297 298 /* Work backwards until we hit the original insert pointer value */ 299 while (tx_queue->insert_count != insert_count) { 300 --tx_queue->insert_count; 301 buffer = __efx_tx_queue_get_insert_buffer(tx_queue); 302 efx_dequeue_buffer(tx_queue, buffer, &pkts_compl, &bytes_compl, 303 &efv_pkts_compl); 304 } 305 } 306 307 struct efx_tx_buffer *efx_tx_map_chunk(struct efx_tx_queue *tx_queue, 308 dma_addr_t dma_addr, size_t len) 309 { 310 const struct efx_nic_type *nic_type = tx_queue->efx->type; 311 struct efx_tx_buffer *buffer; 312 unsigned int dma_len; 313 314 /* Map the fragment taking account of NIC-dependent DMA limits. */ 315 do { 316 buffer = efx_tx_queue_get_insert_buffer(tx_queue); 317 318 if (nic_type->tx_limit_len) 319 dma_len = nic_type->tx_limit_len(tx_queue, dma_addr, len); 320 else 321 dma_len = len; 322 323 buffer->len = dma_len; 324 buffer->dma_addr = dma_addr; 325 buffer->flags = EFX_TX_BUF_CONT; 326 len -= dma_len; 327 dma_addr += dma_len; 328 ++tx_queue->insert_count; 329 } while (len); 330 331 return buffer; 332 } 333 334 int efx_tx_tso_header_length(struct sk_buff *skb) 335 { 336 size_t header_len; 337 338 if (skb->encapsulation) 339 header_len = skb_inner_transport_header(skb) - 340 skb->data + 341 (inner_tcp_hdr(skb)->doff << 2u); 342 else 343 header_len = skb_transport_header(skb) - skb->data + 344 (tcp_hdr(skb)->doff << 2u); 345 return header_len; 346 } 347 348 /* Map all data from an SKB for DMA and create descriptors on the queue. */ 349 int efx_tx_map_data(struct efx_tx_queue *tx_queue, struct sk_buff *skb, 350 unsigned int segment_count) 351 { 352 struct efx_nic *efx = tx_queue->efx; 353 struct device *dma_dev = &efx->pci_dev->dev; 354 unsigned int frag_index, nr_frags; 355 dma_addr_t dma_addr, unmap_addr; 356 unsigned short dma_flags; 357 size_t len, unmap_len; 358 359 nr_frags = skb_shinfo(skb)->nr_frags; 360 frag_index = 0; 361 362 /* Map header data. */ 363 len = skb_headlen(skb); 364 dma_addr = dma_map_single(dma_dev, skb->data, len, DMA_TO_DEVICE); 365 dma_flags = EFX_TX_BUF_MAP_SINGLE; 366 unmap_len = len; 367 unmap_addr = dma_addr; 368 369 if (unlikely(dma_mapping_error(dma_dev, dma_addr))) 370 return -EIO; 371 372 if (segment_count) { 373 /* For TSO we need to put the header in to a separate 374 * descriptor. Map this separately if necessary. 375 */ 376 size_t header_len = efx_tx_tso_header_length(skb); 377 378 if (header_len != len) { 379 tx_queue->tso_long_headers++; 380 efx_tx_map_chunk(tx_queue, dma_addr, header_len); 381 len -= header_len; 382 dma_addr += header_len; 383 } 384 } 385 386 /* Add descriptors for each fragment. */ 387 do { 388 struct efx_tx_buffer *buffer; 389 skb_frag_t *fragment; 390 391 buffer = efx_tx_map_chunk(tx_queue, dma_addr, len); 392 393 /* The final descriptor for a fragment is responsible for 394 * unmapping the whole fragment. 395 */ 396 buffer->flags = EFX_TX_BUF_CONT | dma_flags; 397 buffer->unmap_len = unmap_len; 398 buffer->dma_offset = buffer->dma_addr - unmap_addr; 399 400 if (frag_index >= nr_frags) { 401 /* Store SKB details with the final buffer for 402 * the completion. 403 */ 404 buffer->skb = skb; 405 buffer->flags = EFX_TX_BUF_SKB | dma_flags; 406 return 0; 407 } 408 409 /* Move on to the next fragment. */ 410 fragment = &skb_shinfo(skb)->frags[frag_index++]; 411 len = skb_frag_size(fragment); 412 dma_addr = skb_frag_dma_map(dma_dev, fragment, 0, len, 413 DMA_TO_DEVICE); 414 dma_flags = 0; 415 unmap_len = len; 416 unmap_addr = dma_addr; 417 418 if (unlikely(dma_mapping_error(dma_dev, dma_addr))) 419 return -EIO; 420 } while (1); 421 } 422 423 unsigned int efx_tx_max_skb_descs(struct efx_nic *efx) 424 { 425 /* Header and payload descriptor for each output segment, plus 426 * one for every input fragment boundary within a segment 427 */ 428 unsigned int max_descs = EFX_TSO_MAX_SEGS * 2 + MAX_SKB_FRAGS; 429 430 /* Possibly one more per segment for option descriptors */ 431 if (efx_nic_rev(efx) >= EFX_REV_HUNT_A0) 432 max_descs += EFX_TSO_MAX_SEGS; 433 434 /* Possibly more for PCIe page boundaries within input fragments */ 435 if (PAGE_SIZE > EFX_PAGE_SIZE) 436 max_descs += max_t(unsigned int, MAX_SKB_FRAGS, 437 DIV_ROUND_UP(GSO_LEGACY_MAX_SIZE, 438 EFX_PAGE_SIZE)); 439 440 return max_descs; 441 } 442 443 /* 444 * Fallback to software TSO. 445 * 446 * This is used if we are unable to send a GSO packet through hardware TSO. 447 * This should only ever happen due to per-queue restrictions - unsupported 448 * packets should first be filtered by the feature flags. 449 * 450 * Returns 0 on success, error code otherwise. 451 */ 452 int efx_tx_tso_fallback(struct efx_tx_queue *tx_queue, struct sk_buff *skb) 453 { 454 struct sk_buff *segments, *next; 455 456 segments = skb_gso_segment(skb, 0); 457 if (IS_ERR(segments)) 458 return PTR_ERR(segments); 459 460 dev_consume_skb_any(skb); 461 462 skb_list_walk_safe(segments, skb, next) { 463 skb_mark_not_on_list(skb); 464 efx_enqueue_skb(tx_queue, skb); 465 } 466 467 return 0; 468 } 469