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 efx_tx_cb_page_count(struct efx_tx_queue * tx_queue)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 efx_siena_probe_tx_queue(struct efx_tx_queue * tx_queue)23 int efx_siena_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 efx_siena_init_tx_queue(struct efx_tx_queue * tx_queue)68 void efx_siena_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_siena_ptp_use_mac_tx_timestamps(efx) && 85 tx_queue->channel == efx_siena_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 efx_siena_remove_tx_queue(struct efx_tx_queue * tx_queue)98 void efx_siena_remove_tx_queue(struct efx_tx_queue *tx_queue) 99 { 100 int i; 101 102 if (!tx_queue->buffer) 103 return; 104 105 netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev, 106 "destroying TX queue %d\n", tx_queue->queue); 107 efx_nic_remove_tx(tx_queue); 108 109 if (tx_queue->cb_page) { 110 for (i = 0; i < efx_tx_cb_page_count(tx_queue); i++) 111 efx_siena_free_buffer(tx_queue->efx, 112 &tx_queue->cb_page[i]); 113 kfree(tx_queue->cb_page); 114 tx_queue->cb_page = NULL; 115 } 116 117 kfree(tx_queue->buffer); 118 tx_queue->buffer = NULL; 119 tx_queue->channel->tx_queue_by_type[tx_queue->type] = NULL; 120 } 121 efx_dequeue_buffer(struct efx_tx_queue * tx_queue,struct efx_tx_buffer * buffer,unsigned int * pkts_compl,unsigned int * bytes_compl)122 static void efx_dequeue_buffer(struct efx_tx_queue *tx_queue, 123 struct efx_tx_buffer *buffer, 124 unsigned int *pkts_compl, 125 unsigned int *bytes_compl) 126 { 127 if (buffer->unmap_len) { 128 struct device *dma_dev = &tx_queue->efx->pci_dev->dev; 129 dma_addr_t unmap_addr = buffer->dma_addr - buffer->dma_offset; 130 131 if (buffer->flags & EFX_TX_BUF_MAP_SINGLE) 132 dma_unmap_single(dma_dev, unmap_addr, buffer->unmap_len, 133 DMA_TO_DEVICE); 134 else 135 dma_unmap_page(dma_dev, unmap_addr, buffer->unmap_len, 136 DMA_TO_DEVICE); 137 buffer->unmap_len = 0; 138 } 139 140 if (buffer->flags & EFX_TX_BUF_SKB) { 141 struct sk_buff *skb = (struct sk_buff *)buffer->skb; 142 143 EFX_WARN_ON_PARANOID(!pkts_compl || !bytes_compl); 144 (*pkts_compl)++; 145 (*bytes_compl) += skb->len; 146 if (tx_queue->timestamping && 147 (tx_queue->completed_timestamp_major || 148 tx_queue->completed_timestamp_minor)) { 149 struct skb_shared_hwtstamps hwtstamp; 150 151 hwtstamp.hwtstamp = 152 efx_siena_ptp_nic_to_kernel_time(tx_queue); 153 skb_tstamp_tx(skb, &hwtstamp); 154 155 tx_queue->completed_timestamp_major = 0; 156 tx_queue->completed_timestamp_minor = 0; 157 } 158 dev_consume_skb_any((struct sk_buff *)buffer->skb); 159 netif_vdbg(tx_queue->efx, tx_done, tx_queue->efx->net_dev, 160 "TX queue %d transmission id %x complete\n", 161 tx_queue->queue, tx_queue->read_count); 162 } else if (buffer->flags & EFX_TX_BUF_XDP) { 163 xdp_return_frame_rx_napi(buffer->xdpf); 164 } 165 166 buffer->len = 0; 167 buffer->flags = 0; 168 } 169 efx_siena_fini_tx_queue(struct efx_tx_queue * tx_queue)170 void efx_siena_fini_tx_queue(struct efx_tx_queue *tx_queue) 171 { 172 struct efx_tx_buffer *buffer; 173 174 netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev, 175 "shutting down TX queue %d\n", tx_queue->queue); 176 177 if (!tx_queue->buffer) 178 return; 179 180 /* Free any buffers left in the ring */ 181 while (tx_queue->read_count != tx_queue->write_count) { 182 unsigned int pkts_compl = 0, bytes_compl = 0; 183 184 buffer = &tx_queue->buffer[tx_queue->read_count & tx_queue->ptr_mask]; 185 efx_dequeue_buffer(tx_queue, buffer, &pkts_compl, &bytes_compl); 186 187 ++tx_queue->read_count; 188 } 189 tx_queue->xmit_pending = false; 190 netdev_tx_reset_queue(tx_queue->core_txq); 191 } 192 193 /* Remove packets from the TX queue 194 * 195 * This removes packets from the TX queue, up to and including the 196 * specified index. 197 */ efx_dequeue_buffers(struct efx_tx_queue * tx_queue,unsigned int index,unsigned int * pkts_compl,unsigned int * bytes_compl)198 static void efx_dequeue_buffers(struct efx_tx_queue *tx_queue, 199 unsigned int index, 200 unsigned int *pkts_compl, 201 unsigned int *bytes_compl) 202 { 203 struct efx_nic *efx = tx_queue->efx; 204 unsigned int stop_index, read_ptr; 205 206 stop_index = (index + 1) & tx_queue->ptr_mask; 207 read_ptr = tx_queue->read_count & tx_queue->ptr_mask; 208 209 while (read_ptr != stop_index) { 210 struct efx_tx_buffer *buffer = &tx_queue->buffer[read_ptr]; 211 212 if (!efx_tx_buffer_in_use(buffer)) { 213 netif_err(efx, tx_err, efx->net_dev, 214 "TX queue %d spurious TX completion id %d\n", 215 tx_queue->queue, read_ptr); 216 efx_siena_schedule_reset(efx, RESET_TYPE_TX_SKIP); 217 return; 218 } 219 220 efx_dequeue_buffer(tx_queue, buffer, pkts_compl, bytes_compl); 221 222 ++tx_queue->read_count; 223 read_ptr = tx_queue->read_count & tx_queue->ptr_mask; 224 } 225 } 226 efx_siena_xmit_done_check_empty(struct efx_tx_queue * tx_queue)227 void efx_siena_xmit_done_check_empty(struct efx_tx_queue *tx_queue) 228 { 229 if ((int)(tx_queue->read_count - tx_queue->old_write_count) >= 0) { 230 tx_queue->old_write_count = READ_ONCE(tx_queue->write_count); 231 if (tx_queue->read_count == tx_queue->old_write_count) { 232 /* Ensure that read_count is flushed. */ 233 smp_mb(); 234 tx_queue->empty_read_count = 235 tx_queue->read_count | EFX_EMPTY_COUNT_VALID; 236 } 237 } 238 } 239 efx_siena_xmit_done(struct efx_tx_queue * tx_queue,unsigned int index)240 void efx_siena_xmit_done(struct efx_tx_queue *tx_queue, unsigned int index) 241 { 242 unsigned int fill_level, pkts_compl = 0, bytes_compl = 0; 243 struct efx_nic *efx = tx_queue->efx; 244 245 EFX_WARN_ON_ONCE_PARANOID(index > tx_queue->ptr_mask); 246 247 efx_dequeue_buffers(tx_queue, index, &pkts_compl, &bytes_compl); 248 tx_queue->pkts_compl += pkts_compl; 249 tx_queue->bytes_compl += bytes_compl; 250 251 if (pkts_compl > 1) 252 ++tx_queue->merge_events; 253 254 /* See if we need to restart the netif queue. This memory 255 * barrier ensures that we write read_count (inside 256 * efx_dequeue_buffers()) before reading the queue status. 257 */ 258 smp_mb(); 259 if (unlikely(netif_tx_queue_stopped(tx_queue->core_txq)) && 260 likely(efx->port_enabled) && 261 likely(netif_device_present(efx->net_dev))) { 262 fill_level = efx_channel_tx_fill_level(tx_queue->channel); 263 if (fill_level <= efx->txq_wake_thresh) 264 netif_tx_wake_queue(tx_queue->core_txq); 265 } 266 267 efx_siena_xmit_done_check_empty(tx_queue); 268 } 269 270 /* Remove buffers put into a tx_queue for the current packet. 271 * None of the buffers must have an skb attached. 272 */ efx_siena_enqueue_unwind(struct efx_tx_queue * tx_queue,unsigned int insert_count)273 void efx_siena_enqueue_unwind(struct efx_tx_queue *tx_queue, 274 unsigned int insert_count) 275 { 276 struct efx_tx_buffer *buffer; 277 unsigned int bytes_compl = 0; 278 unsigned int pkts_compl = 0; 279 280 /* Work backwards until we hit the original insert pointer value */ 281 while (tx_queue->insert_count != insert_count) { 282 --tx_queue->insert_count; 283 buffer = __efx_tx_queue_get_insert_buffer(tx_queue); 284 efx_dequeue_buffer(tx_queue, buffer, &pkts_compl, &bytes_compl); 285 } 286 } 287 efx_siena_tx_map_chunk(struct efx_tx_queue * tx_queue,dma_addr_t dma_addr,size_t len)288 struct efx_tx_buffer *efx_siena_tx_map_chunk(struct efx_tx_queue *tx_queue, 289 dma_addr_t dma_addr, size_t len) 290 { 291 const struct efx_nic_type *nic_type = tx_queue->efx->type; 292 struct efx_tx_buffer *buffer; 293 unsigned int dma_len; 294 295 /* Map the fragment taking account of NIC-dependent DMA limits. */ 296 do { 297 buffer = efx_tx_queue_get_insert_buffer(tx_queue); 298 299 if (nic_type->tx_limit_len) 300 dma_len = nic_type->tx_limit_len(tx_queue, dma_addr, len); 301 else 302 dma_len = len; 303 304 buffer->len = dma_len; 305 buffer->dma_addr = dma_addr; 306 buffer->flags = EFX_TX_BUF_CONT; 307 len -= dma_len; 308 dma_addr += dma_len; 309 ++tx_queue->insert_count; 310 } while (len); 311 312 return buffer; 313 } 314 efx_tx_tso_header_length(struct sk_buff * skb)315 static int efx_tx_tso_header_length(struct sk_buff *skb) 316 { 317 size_t header_len; 318 319 if (skb->encapsulation) 320 header_len = skb_inner_transport_offset(skb) + 321 (inner_tcp_hdr(skb)->doff << 2u); 322 else 323 header_len = skb_transport_offset(skb) + 324 (tcp_hdr(skb)->doff << 2u); 325 return header_len; 326 } 327 328 /* Map all data from an SKB for DMA and create descriptors on the queue. */ efx_siena_tx_map_data(struct efx_tx_queue * tx_queue,struct sk_buff * skb,unsigned int segment_count)329 int efx_siena_tx_map_data(struct efx_tx_queue *tx_queue, struct sk_buff *skb, 330 unsigned int segment_count) 331 { 332 struct efx_nic *efx = tx_queue->efx; 333 struct device *dma_dev = &efx->pci_dev->dev; 334 unsigned int frag_index, nr_frags; 335 dma_addr_t dma_addr, unmap_addr; 336 unsigned short dma_flags; 337 size_t len, unmap_len; 338 339 nr_frags = skb_shinfo(skb)->nr_frags; 340 frag_index = 0; 341 342 /* Map header data. */ 343 len = skb_headlen(skb); 344 dma_addr = dma_map_single(dma_dev, skb->data, len, DMA_TO_DEVICE); 345 dma_flags = EFX_TX_BUF_MAP_SINGLE; 346 unmap_len = len; 347 unmap_addr = dma_addr; 348 349 if (unlikely(dma_mapping_error(dma_dev, dma_addr))) 350 return -EIO; 351 352 if (segment_count) { 353 /* For TSO we need to put the header in to a separate 354 * descriptor. Map this separately if necessary. 355 */ 356 size_t header_len = efx_tx_tso_header_length(skb); 357 358 if (header_len != len) { 359 tx_queue->tso_long_headers++; 360 efx_siena_tx_map_chunk(tx_queue, dma_addr, header_len); 361 len -= header_len; 362 dma_addr += header_len; 363 } 364 } 365 366 /* Add descriptors for each fragment. */ 367 do { 368 struct efx_tx_buffer *buffer; 369 skb_frag_t *fragment; 370 371 buffer = efx_siena_tx_map_chunk(tx_queue, dma_addr, len); 372 373 /* The final descriptor for a fragment is responsible for 374 * unmapping the whole fragment. 375 */ 376 buffer->flags = EFX_TX_BUF_CONT | dma_flags; 377 buffer->unmap_len = unmap_len; 378 buffer->dma_offset = buffer->dma_addr - unmap_addr; 379 380 if (frag_index >= nr_frags) { 381 /* Store SKB details with the final buffer for 382 * the completion. 383 */ 384 buffer->skb = skb; 385 buffer->flags = EFX_TX_BUF_SKB | dma_flags; 386 return 0; 387 } 388 389 /* Move on to the next fragment. */ 390 fragment = &skb_shinfo(skb)->frags[frag_index++]; 391 len = skb_frag_size(fragment); 392 dma_addr = skb_frag_dma_map(dma_dev, fragment, 0, len, 393 DMA_TO_DEVICE); 394 dma_flags = 0; 395 unmap_len = len; 396 unmap_addr = dma_addr; 397 398 if (unlikely(dma_mapping_error(dma_dev, dma_addr))) 399 return -EIO; 400 } while (1); 401 } 402 efx_siena_tx_max_skb_descs(struct efx_nic * efx)403 unsigned int efx_siena_tx_max_skb_descs(struct efx_nic *efx) 404 { 405 /* Header and payload descriptor for each output segment, plus 406 * one for every input fragment boundary within a segment 407 */ 408 unsigned int max_descs = EFX_TSO_MAX_SEGS * 2 + MAX_SKB_FRAGS; 409 410 /* Possibly one more per segment for option descriptors */ 411 if (efx_nic_rev(efx) >= EFX_REV_HUNT_A0) 412 max_descs += EFX_TSO_MAX_SEGS; 413 414 /* Possibly more for PCIe page boundaries within input fragments */ 415 if (PAGE_SIZE > EFX_PAGE_SIZE) 416 max_descs += max_t(unsigned int, MAX_SKB_FRAGS, 417 DIV_ROUND_UP(GSO_MAX_SIZE, EFX_PAGE_SIZE)); 418 419 return max_descs; 420 } 421 422 /* 423 * Fallback to software TSO. 424 * 425 * This is used if we are unable to send a GSO packet through hardware TSO. 426 * This should only ever happen due to per-queue restrictions - unsupported 427 * packets should first be filtered by the feature flags. 428 * 429 * Returns 0 on success, error code otherwise. 430 */ efx_siena_tx_tso_fallback(struct efx_tx_queue * tx_queue,struct sk_buff * skb)431 int efx_siena_tx_tso_fallback(struct efx_tx_queue *tx_queue, 432 struct sk_buff *skb) 433 { 434 struct sk_buff *segments, *next; 435 436 segments = skb_gso_segment(skb, 0); 437 if (IS_ERR(segments)) 438 return PTR_ERR(segments); 439 440 dev_consume_skb_any(skb); 441 442 skb_list_walk_safe(segments, skb, next) { 443 skb_mark_not_on_list(skb); 444 efx_enqueue_skb(tx_queue, skb); 445 } 446 447 return 0; 448 } 449