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