LXR linux/drivers/net/ethernet/sfc/tx

   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.h"
  14#include "tx_common.h"
  15
  16static 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
  22int 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 */
  51        rc = efx_nic_probe_tx(tx_queue);
  52        if (rc)
  53                goto fail2;
  54
  55        return 0;
  56
  57fail2:
  58        kfree(tx_queue->cb_page);
  59        tx_queue->cb_page = NULL;
  60fail1:
  61        kfree(tx_queue->buffer);
  62        tx_queue->buffer = NULL;
  63        return rc;
  64}
  65
  66void efx_init_tx_queue(struct efx_tx_queue *tx_queue)
  67{
  68        struct efx_nic *efx = tx_queue->efx;
  69
  70        netif_dbg(efx, drv, efx->net_dev,
  71                  "initialising TX queue %d\n", tx_queue->queue);
  72
  73        tx_queue->insert_count = 0;
  74        tx_queue->write_count = 0;
  75        tx_queue->packet_write_count = 0;
  76        tx_queue->old_write_count = 0;
  77        tx_queue->read_count = 0;
  78        tx_queue->old_read_count = 0;
  79        tx_queue->empty_read_count = 0 | EFX_EMPTY_COUNT_VALID;
  80        tx_queue->xmit_more_available = false;
  81        tx_queue->timestamping = (efx_ptp_use_mac_tx_timestamps(efx) &&
  82                                  tx_queue->channel == efx_ptp_channel(efx));
  83        tx_queue->completed_timestamp_major = 0;
  84        tx_queue->completed_timestamp_minor = 0;
  85
  86        tx_queue->xdp_tx = efx_channel_is_xdp_tx(tx_queue->channel);
  87
  88        /* Set up default function pointers. These may get replaced by
  89         * efx_nic_init_tx() based off NIC/queue capabilities.
  90         */
  91        tx_queue->handle_tso = efx_enqueue_skb_tso;
  92
  93        /* Set up TX descriptor ring */
  94        efx_nic_init_tx(tx_queue);
  95
  96        tx_queue->initialised = true;
  97}
  98
  99void efx_fini_tx_queue(struct efx_tx_queue *tx_queue)
 100{
 101        struct efx_tx_buffer *buffer;
 102
 103        netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev,
 104                  "shutting down TX queue %d\n", tx_queue->queue);
 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
 113                buffer = &tx_queue->buffer[tx_queue->read_count & tx_queue->ptr_mask];
 114                efx_dequeue_buffer(tx_queue, buffer, &pkts_compl, &bytes_compl);
 115
 116                ++tx_queue->read_count;
 117        }
 118        tx_queue->xmit_more_available = false;
 119        netdev_tx_reset_queue(tx_queue->core_txq);
 120}
 121
 122void efx_remove_tx_queue(struct efx_tx_queue *tx_queue)
 123{
 124        int i;
 125
 126        if (!tx_queue->buffer)
 127                return;
 128
 129        netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev,
 130                  "destroying TX queue %d\n", tx_queue->queue);
 131        efx_nic_remove_tx(tx_queue);
 132
 133        if (tx_queue->cb_page) {
 134                for (i = 0; i < efx_tx_cb_page_count(tx_queue); i++)
 135                        efx_nic_free_buffer(tx_queue->efx,
 136                                            &tx_queue->cb_page[i]);
 137                kfree(tx_queue->cb_page);
 138                tx_queue->cb_page = NULL;
 139        }
 140
 141        kfree(tx_queue->buffer);
 142        tx_queue->buffer = NULL;
 143}
 144
 145void efx_dequeue_buffer(struct efx_tx_queue *tx_queue,
 146                        struct efx_tx_buffer *buffer,
 147                        unsigned int *pkts_compl,
 148                        unsigned int *bytes_compl)
 149{
 150        if (buffer->unmap_len) {
 151                struct device *dma_dev = &tx_queue->efx->pci_dev->dev;
 152                dma_addr_t unmap_addr = buffer->dma_addr - buffer->dma_offset;
 153
 154                if (buffer->flags & EFX_TX_BUF_MAP_SINGLE)
 155                        dma_unmap_single(dma_dev, unmap_addr, buffer->unmap_len,
 156                                         DMA_TO_DEVICE);
 157                else
 158                        dma_unmap_page(dma_dev, unmap_addr, buffer->unmap_len,
 159                                       DMA_TO_DEVICE);
 160                buffer->unmap_len = 0;
 161        }
 162
 163        if (buffer->flags & EFX_TX_BUF_SKB) {
 164                struct sk_buff *skb = (struct sk_buff *)buffer->skb;
 165
 166                EFX_WARN_ON_PARANOID(!pkts_compl || !bytes_compl);
 167                (*pkts_compl)++;
 168                (*bytes_compl) += skb->len;
 169                if (tx_queue->timestamping &&
 170                    (tx_queue->completed_timestamp_major ||
 171                     tx_queue->completed_timestamp_minor)) {
 172                        struct skb_shared_hwtstamps hwtstamp;
 173
 174                        hwtstamp.hwtstamp =
 175                                efx_ptp_nic_to_kernel_time(tx_queue);
 176                        skb_tstamp_tx(skb, &hwtstamp);
 177
 178                        tx_queue->completed_timestamp_major = 0;
 179                        tx_queue->completed_timestamp_minor = 0;
 180                }
 181                dev_consume_skb_any((struct sk_buff *)buffer->skb);
 182                netif_vdbg(tx_queue->efx, tx_done, tx_queue->efx->net_dev,
 183                           "TX queue %d transmission id %x complete\n",
 184                           tx_queue->queue, tx_queue->read_count);
 185        } else if (buffer->flags & EFX_TX_BUF_XDP) {
 186                xdp_return_frame_rx_napi(buffer->xdpf);
 187        }
 188
 189        buffer->len = 0;
 190        buffer->flags = 0;
 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 */
 198static 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_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
 227void efx_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
 240void efx_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        struct efx_tx_queue *txq2;
 245
 246        EFX_WARN_ON_ONCE_PARANOID(index > tx_queue->ptr_mask);
 247
 248        efx_dequeue_buffers(tx_queue, index, &pkts_compl, &bytes_compl);
 249        tx_queue->pkts_compl += pkts_compl;
 250        tx_queue->bytes_compl += bytes_compl;
 251
 252        if (pkts_compl > 1)
 253                ++tx_queue->merge_events;
 254
 255        /* See if we need to restart the netif queue.  This memory
 256         * barrier ensures that we write read_count (inside
 257         * efx_dequeue_buffers()) before reading the queue status.
 258         */
 259        smp_mb();
 260        if (unlikely(netif_tx_queue_stopped(tx_queue->core_txq)) &&
 261            likely(efx->port_enabled) &&
 262            likely(netif_device_present(efx->net_dev))) {
 263                txq2 = efx_tx_queue_partner(tx_queue);
 264                fill_level = max(tx_queue->insert_count - tx_queue->read_count,
 265                                 txq2->insert_count - txq2->read_count);
 266                if (fill_level <= efx->txq_wake_thresh)
 267                        netif_tx_wake_queue(tx_queue->core_txq);
 268        }
 269
 270        efx_xmit_done_check_empty(tx_queue);
 271}
 272
 273/* Remove buffers put into a tx_queue for the current packet.
 274 * None of the buffers must have an skb attached.
 275 */
 276void efx_enqueue_unwind(struct efx_tx_queue *tx_queue,
 277                        unsigned int insert_count)
 278{
 279        struct efx_tx_buffer *buffer;
 280        unsigned int bytes_compl = 0;
 281        unsigned int pkts_compl = 0;
 282
 283        /* Work backwards until we hit the original insert pointer value */
 284        while (tx_queue->insert_count != insert_count) {
 285                --tx_queue->insert_count;
 286                buffer = __efx_tx_queue_get_insert_buffer(tx_queue);
 287                efx_dequeue_buffer(tx_queue, buffer, &pkts_compl, &bytes_compl);
 288        }
 289}
 290
 291struct efx_tx_buffer *efx_tx_map_chunk(struct efx_tx_queue *tx_queue,
 292                                       dma_addr_t dma_addr, size_t len)
 293{
 294        const struct efx_nic_type *nic_type = tx_queue->efx->type;
 295        struct efx_tx_buffer *buffer;
 296        unsigned int dma_len;
 297
 298        /* Map the fragment taking account of NIC-dependent DMA limits. */
 299        do {
 300                buffer = efx_tx_queue_get_insert_buffer(tx_queue);
 301                dma_len = nic_type->tx_limit_len(tx_queue, dma_addr, len);
 302
 303                buffer->len = dma_len;
 304                buffer->dma_addr = dma_addr;
 305                buffer->flags = EFX_TX_BUF_CONT;
 306                len -= dma_len;
 307                dma_addr += dma_len;
 308                ++tx_queue->insert_count;
 309        } while (len);
 310
 311        return buffer;
 312}
 313
 314/* Map all data from an SKB for DMA and create descriptors on the queue. */
 315int efx_tx_map_data(struct efx_tx_queue *tx_queue, struct sk_buff *skb,
 316                    unsigned int segment_count)
 317{
 318        struct efx_nic *efx = tx_queue->efx;
 319        struct device *dma_dev = &efx->pci_dev->dev;
 320        unsigned int frag_index, nr_frags;
 321        dma_addr_t dma_addr, unmap_addr;
 322        unsigned short dma_flags;
 323        size_t len, unmap_len;
 324
 325        nr_frags = skb_shinfo(skb)->nr_frags;
 326        frag_index = 0;
 327
 328        /* Map header data. */
 329        len = skb_headlen(skb);
 330        dma_addr = dma_map_single(dma_dev, skb->data, len, DMA_TO_DEVICE);
 331        dma_flags = EFX_TX_BUF_MAP_SINGLE;
 332        unmap_len = len;
 333        unmap_addr = dma_addr;
 334
 335        if (unlikely(dma_mapping_error(dma_dev, dma_addr)))
 336                return -EIO;
 337
 338        if (segment_count) {
 339                /* For TSO we need to put the header in to a separate
 340                 * descriptor. Map this separately if necessary.
 341                 */
 342                size_t header_len = skb_transport_header(skb) - skb->data +
 343                                (tcp_hdr(skb)->doff << 2u);
 344
 345                if (header_len != len) {
 346                        tx_queue->tso_long_headers++;
 347                        efx_tx_map_chunk(tx_queue, dma_addr, header_len);
 348                        len -= header_len;
 349                        dma_addr += header_len;
 350                }
 351        }
 352
 353        /* Add descriptors for each fragment. */
 354        do {
 355                struct efx_tx_buffer *buffer;
 356                skb_frag_t *fragment;
 357
 358                buffer = efx_tx_map_chunk(tx_queue, dma_addr, len);
 359
 360                /* The final descriptor for a fragment is responsible for
 361                 * unmapping the whole fragment.
 362                 */
 363                buffer->flags = EFX_TX_BUF_CONT | dma_flags;
 364                buffer->unmap_len = unmap_len;
 365                buffer->dma_offset = buffer->dma_addr - unmap_addr;
 366
 367                if (frag_index >= nr_frags) {
 368                        /* Store SKB details with the final buffer for
 369                         * the completion.
 370                         */
 371                        buffer->skb = skb;
 372                        buffer->flags = EFX_TX_BUF_SKB | dma_flags;
 373                        return 0;
 374                }
 375
 376                /* Move on to the next fragment. */
 377                fragment = &skb_shinfo(skb)->frags[frag_index++];
 378                len = skb_frag_size(fragment);
 379                dma_addr = skb_frag_dma_map(dma_dev, fragment, 0, len,
 380                                            DMA_TO_DEVICE);
 381                dma_flags = 0;
 382                unmap_len = len;
 383                unmap_addr = dma_addr;
 384
 385                if (unlikely(dma_mapping_error(dma_dev, dma_addr)))
 386                        return -EIO;
 387        } while (1);
 388}
 389
 390unsigned int efx_tx_max_skb_descs(struct efx_nic *efx)
 391{
 392        /* Header and payload descriptor for each output segment, plus
 393         * one for every input fragment boundary within a segment
 394         */
 395        unsigned int max_descs = EFX_TSO_MAX_SEGS * 2 + MAX_SKB_FRAGS;
 396
 397        /* Possibly one more per segment for option descriptors */
 398        if (efx_nic_rev(efx) >= EFX_REV_HUNT_A0)
 399                max_descs += EFX_TSO_MAX_SEGS;
 400
 401        /* Possibly more for PCIe page boundaries within input fragments */
 402        if (PAGE_SIZE > EFX_PAGE_SIZE)
 403                max_descs += max_t(unsigned int, MAX_SKB_FRAGS,
 404                                   DIV_ROUND_UP(GSO_MAX_SIZE, EFX_PAGE_SIZE));
 405
 406        return max_descs;
 407}
 408