drivers/net/wireless/mediatek/mt76/dma.c

   1 // SPDX-License-Identifier: ISC
   2 /*
   3  * Copyright (C) 2016 Felix Fietkau <nbd@nbd.name>
   4  */
   5
   6 #include <linux/dma-mapping.h>
   7 #include "mt76.h"
   8 #include "dma.h"
   9
  10 static int
  11 mt76_dma_alloc_queue(struct mt76_dev *dev, struct mt76_queue *q,
  12                      int idx, int n_desc, int bufsize,
  13                      u32 ring_base)
  14 {
  15         int size;
  16         int i;
  17
  18         spin_lock_init(&q->lock);
  19
  20         q->regs = dev->mmio.regs + ring_base + idx * MT_RING_SIZE;
  21         q->ndesc = n_desc;
  22         q->buf_size = bufsize;
  23         q->hw_idx = idx;
  24
  25         size = q->ndesc * sizeof(struct mt76_desc);
  26         q->desc = dmam_alloc_coherent(dev->dev, size, &q->desc_dma, GFP_KERNEL);
  27         if (!q->desc)
  28                 return -ENOMEM;
  29
  30         size = q->ndesc * sizeof(*q->entry);
  31         q->entry = devm_kzalloc(dev->dev, size, GFP_KERNEL);
  32         if (!q->entry)
  33                 return -ENOMEM;
  34
  35         /* clear descriptors */
  36         for (i = 0; i < q->ndesc; i++)
  37                 q->desc[i].ctrl = cpu_to_le32(MT_DMA_CTL_DMA_DONE);
  38
  39         writel(q->desc_dma, &q->regs->desc_base);
  40         writel(0, &q->regs->cpu_idx);
  41         writel(0, &q->regs->dma_idx);
  42         writel(q->ndesc, &q->regs->ring_size);
  43
  44         return 0;
  45 }
  46
  47 static int
  48 mt76_dma_add_buf(struct mt76_dev *dev, struct mt76_queue *q,
  49                  struct mt76_queue_buf *buf, int nbufs, u32 info,
  50                  struct sk_buff *skb, void *txwi)
  51 {
  52         struct mt76_desc *desc;
  53         u32 ctrl;
  54         int i, idx = -1;
  55
  56         if (txwi) {
  57                 q->entry[q->head].txwi = DMA_DUMMY_DATA;
  58                 q->entry[q->head].skip_buf0 = true;
  59         }
  60
  61         for (i = 0; i < nbufs; i += 2, buf += 2) {
  62                 u32 buf0 = buf[0].addr, buf1 = 0;
  63
  64                 ctrl = FIELD_PREP(MT_DMA_CTL_SD_LEN0, buf[0].len);
  65                 if (i < nbufs - 1) {
  66                         buf1 = buf[1].addr;
  67                         ctrl |= FIELD_PREP(MT_DMA_CTL_SD_LEN1, buf[1].len);
  68                 }
  69
  70                 if (i == nbufs - 1)
  71                         ctrl |= MT_DMA_CTL_LAST_SEC0;
  72                 else if (i == nbufs - 2)
  73                         ctrl |= MT_DMA_CTL_LAST_SEC1;
  74
  75                 idx = q->head;
  76                 q->head = (q->head + 1) % q->ndesc;
  77
  78                 desc = &q->desc[idx];
  79
  80                 WRITE_ONCE(desc->buf0, cpu_to_le32(buf0));
  81                 WRITE_ONCE(desc->buf1, cpu_to_le32(buf1));
  82                 WRITE_ONCE(desc->info, cpu_to_le32(info));
  83                 WRITE_ONCE(desc->ctrl, cpu_to_le32(ctrl));
  84
  85                 q->queued++;
  86         }
  87
  88         q->entry[idx].txwi = txwi;
  89         q->entry[idx].skb = skb;
  90
  91         return idx;
  92 }
  93
  94 static void
  95 mt76_dma_tx_cleanup_idx(struct mt76_dev *dev, struct mt76_queue *q, int idx,
  96                         struct mt76_queue_entry *prev_e)
  97 {
  98         struct mt76_queue_entry *e = &q->entry[idx];
  99         __le32 __ctrl = READ_ONCE(q->desc[idx].ctrl);
 100         u32 ctrl = le32_to_cpu(__ctrl);
 101
 102         if (!e->skip_buf0) {
 103                 __le32 addr = READ_ONCE(q->desc[idx].buf0);
 104                 u32 len = FIELD_GET(MT_DMA_CTL_SD_LEN0, ctrl);
 105
 106                 dma_unmap_single(dev->dev, le32_to_cpu(addr), len,
 107                                  DMA_TO_DEVICE);
 108         }
 109
 110         if (!(ctrl & MT_DMA_CTL_LAST_SEC0)) {
 111                 __le32 addr = READ_ONCE(q->desc[idx].buf1);
 112                 u32 len = FIELD_GET(MT_DMA_CTL_SD_LEN1, ctrl);
 113
 114                 dma_unmap_single(dev->dev, le32_to_cpu(addr), len,
 115                                  DMA_TO_DEVICE);
 116         }
 117
 118         if (e->txwi == DMA_DUMMY_DATA)
 119                 e->txwi = NULL;
 120
 121         if (e->skb == DMA_DUMMY_DATA)
 122                 e->skb = NULL;
 123
 124         *prev_e = *e;
 125         memset(e, 0, sizeof(*e));
 126 }
 127
 128 static void
 129 mt76_dma_sync_idx(struct mt76_dev *dev, struct mt76_queue *q)
 130 {
 131         writel(q->desc_dma, &q->regs->desc_base);
 132         writel(q->ndesc, &q->regs->ring_size);
 133         q->head = readl(&q->regs->dma_idx);
 134         q->tail = q->head;
 135         writel(q->head, &q->regs->cpu_idx);
 136 }
 137
 138 static void
 139 mt76_dma_tx_cleanup(struct mt76_dev *dev, enum mt76_txq_id qid, bool flush)
 140 {
 141         struct mt76_sw_queue *sq = &dev->q_tx[qid];
 142         struct mt76_queue *q = sq->q;
 143         struct mt76_queue_entry entry;
 144         unsigned int n_swq_queued[4] = {};
 145         unsigned int n_queued = 0;
 146         bool wake = false;
 147         int i, last;
 148
 149         if (!q)
 150                 return;
 151
 152         if (flush)
 153                 last = -1;
 154         else
 155                 last = readl(&q->regs->dma_idx);
 156
 157         while ((q->queued > n_queued) && q->tail != last) {
 158                 mt76_dma_tx_cleanup_idx(dev, q, q->tail, &entry);
 159                 if (entry.schedule)
 160                         n_swq_queued[entry.qid]++;
 161
 162                 q->tail = (q->tail + 1) % q->ndesc;
 163                 n_queued++;
 164
 165                 if (entry.skb)
 166                         dev->drv->tx_complete_skb(dev, qid, &entry);
 167
 168                 if (entry.txwi) {
 169                         if (!(dev->drv->drv_flags & MT_DRV_TXWI_NO_FREE))
 170                                 mt76_put_txwi(dev, entry.txwi);
 171                         wake = !flush;
 172                 }
 173
 174                 if (!flush && q->tail == last)
 175                         last = readl(&q->regs->dma_idx);
 176         }
 177
 178         spin_lock_bh(&q->lock);
 179
 180         q->queued -= n_queued;
 181         for (i = 0; i < ARRAY_SIZE(n_swq_queued); i++) {
 182                 if (!n_swq_queued[i])
 183                         continue;
 184
 185                 dev->q_tx[i].swq_queued -= n_swq_queued[i];
 186         }
 187
 188         if (flush)
 189                 mt76_dma_sync_idx(dev, q);
 190
 191         wake = wake && q->stopped &&
 192                qid < IEEE80211_NUM_ACS && q->queued < q->ndesc - 8;
 193         if (wake)
 194                 q->stopped = false;
 195
 196         if (!q->queued)
 197                 wake_up(&dev->tx_wait);
 198
 199         spin_unlock_bh(&q->lock);
 200
 201         if (wake)
 202                 ieee80211_wake_queue(dev->hw, qid);
 203 }
 204
 205 static void *
 206 mt76_dma_get_buf(struct mt76_dev *dev, struct mt76_queue *q, int idx,
 207                  int *len, u32 *info, bool *more)
 208 {
 209         struct mt76_queue_entry *e = &q->entry[idx];
 210         struct mt76_desc *desc = &q->desc[idx];
 211         dma_addr_t buf_addr;
 212         void *buf = e->buf;
 213         int buf_len = SKB_WITH_OVERHEAD(q->buf_size);
 214
 215         buf_addr = le32_to_cpu(READ_ONCE(desc->buf0));
 216         if (len) {
 217                 u32 ctl = le32_to_cpu(READ_ONCE(desc->ctrl));
 218                 *len = FIELD_GET(MT_DMA_CTL_SD_LEN0, ctl);
 219                 *more = !(ctl & MT_DMA_CTL_LAST_SEC0);
 220         }
 221
 222         if (info)
 223                 *info = le32_to_cpu(desc->info);
 224
 225         dma_unmap_single(dev->dev, buf_addr, buf_len, DMA_FROM_DEVICE);
 226         e->buf = NULL;
 227
 228         return buf;
 229 }
 230
 231 static void *
 232 mt76_dma_dequeue(struct mt76_dev *dev, struct mt76_queue *q, bool flush,
 233                  int *len, u32 *info, bool *more)
 234 {
 235         int idx = q->tail;
 236
 237         *more = false;
 238         if (!q->queued)
 239                 return NULL;
 240
 241         if (!flush && !(q->desc[idx].ctrl & cpu_to_le32(MT_DMA_CTL_DMA_DONE)))
 242                 return NULL;
 243
 244         q->tail = (q->tail + 1) % q->ndesc;
 245         q->queued--;
 246
 247         return mt76_dma_get_buf(dev, q, idx, len, info, more);
 248 }
 249
 250 static void
 251 mt76_dma_kick_queue(struct mt76_dev *dev, struct mt76_queue *q)
 252 {
 253         writel(q->head, &q->regs->cpu_idx);
 254 }
 255
 256 static int
 257 mt76_dma_tx_queue_skb_raw(struct mt76_dev *dev, enum mt76_txq_id qid,
 258                           struct sk_buff *skb, u32 tx_info)
 259 {
 260         struct mt76_queue *q = dev->q_tx[qid].q;
 261         struct mt76_queue_buf buf;
 262         dma_addr_t addr;
 263
 264         addr = dma_map_single(dev->dev, skb->data, skb->len,
 265                               DMA_TO_DEVICE);
 266         if (unlikely(dma_mapping_error(dev->dev, addr)))
 267                 return -ENOMEM;
 268
 269         buf.addr = addr;
 270         buf.len = skb->len;
 271
 272         spin_lock_bh(&q->lock);
 273         mt76_dma_add_buf(dev, q, &buf, 1, tx_info, skb, NULL);
 274         mt76_dma_kick_queue(dev, q);
 275         spin_unlock_bh(&q->lock);
 276
 277         return 0;
 278 }
 279
 280 static int
 281 mt76_dma_tx_queue_skb(struct mt76_dev *dev, enum mt76_txq_id qid,
 282                       struct sk_buff *skb, struct mt76_wcid *wcid,
 283                       struct ieee80211_sta *sta)
 284 {
 285         struct mt76_queue *q = dev->q_tx[qid].q;
 286         struct mt76_tx_info tx_info = {
 287                 .skb = skb,
 288         };
 289         int len, n = 0, ret = -ENOMEM;
 290         struct mt76_queue_entry e;
 291         struct mt76_txwi_cache *t;
 292         struct sk_buff *iter;
 293         dma_addr_t addr;
 294         u8 *txwi;
 295
 296         t = mt76_get_txwi(dev);
 297         if (!t) {
 298                 ieee80211_free_txskb(dev->hw, skb);
 299                 return -ENOMEM;
 300         }
 301         txwi = mt76_get_txwi_ptr(dev, t);
 302
 303         skb->prev = skb->next = NULL;
 304         if (dev->drv->drv_flags & MT_DRV_TX_ALIGNED4_SKBS)
 305                 mt76_insert_hdr_pad(skb);
 306
 307         len = skb_headlen(skb);
 308         addr = dma_map_single(dev->dev, skb->data, len, DMA_TO_DEVICE);
 309         if (unlikely(dma_mapping_error(dev->dev, addr)))
 310                 goto free;
 311
 312         tx_info.buf[n].addr = t->dma_addr;
 313         tx_info.buf[n++].len = dev->drv->txwi_size;
 314         tx_info.buf[n].addr = addr;
 315         tx_info.buf[n++].len = len;
 316
 317         skb_walk_frags(skb, iter) {
 318                 if (n == ARRAY_SIZE(tx_info.buf))
 319                         goto unmap;
 320
 321                 addr = dma_map_single(dev->dev, iter->data, iter->len,
 322                                       DMA_TO_DEVICE);
 323                 if (unlikely(dma_mapping_error(dev->dev, addr)))
 324                         goto unmap;
 325
 326                 tx_info.buf[n].addr = addr;
 327                 tx_info.buf[n++].len = iter->len;
 328         }
 329         tx_info.nbuf = n;
 330
 331         dma_sync_single_for_cpu(dev->dev, t->dma_addr, dev->drv->txwi_size,
 332                                 DMA_TO_DEVICE);
 333         ret = dev->drv->tx_prepare_skb(dev, txwi, qid, wcid, sta, &tx_info);
 334         dma_sync_single_for_device(dev->dev, t->dma_addr, dev->drv->txwi_size,
 335                                    DMA_TO_DEVICE);
 336         if (ret < 0)
 337                 goto unmap;
 338
 339         if (q->queued + (tx_info.nbuf + 1) / 2 >= q->ndesc - 1) {
 340                 ret = -ENOMEM;
 341                 goto unmap;
 342         }
 343
 344         return mt76_dma_add_buf(dev, q, tx_info.buf, tx_info.nbuf,
 345                                 tx_info.info, tx_info.skb, t);
 346
 347 unmap:
 348         for (n--; n > 0; n--)
 349                 dma_unmap_single(dev->dev, tx_info.buf[n].addr,
 350                                  tx_info.buf[n].len, DMA_TO_DEVICE);
 351
 352 free:
 353         e.skb = tx_info.skb;
 354         e.txwi = t;
 355         dev->drv->tx_complete_skb(dev, qid, &e);
 356         mt76_put_txwi(dev, t);
 357         return ret;
 358 }
 359
 360 static int
 361 mt76_dma_rx_fill(struct mt76_dev *dev, struct mt76_queue *q)
 362 {
 363         dma_addr_t addr;
 364         void *buf;
 365         int frames = 0;
 366         int len = SKB_WITH_OVERHEAD(q->buf_size);
 367         int offset = q->buf_offset;
 368
 369         spin_lock_bh(&q->lock);
 370
 371         while (q->queued < q->ndesc - 1) {
 372                 struct mt76_queue_buf qbuf;
 373
 374                 buf = page_frag_alloc(&q->rx_page, q->buf_size, GFP_ATOMIC);
 375                 if (!buf)
 376                         break;
 377
 378                 addr = dma_map_single(dev->dev, buf, len, DMA_FROM_DEVICE);
 379                 if (unlikely(dma_mapping_error(dev->dev, addr))) {
 380                         skb_free_frag(buf);
 381                         break;
 382                 }
 383
 384                 qbuf.addr = addr + offset;
 385                 qbuf.len = len - offset;
 386                 mt76_dma_add_buf(dev, q, &qbuf, 1, 0, buf, NULL);
 387                 frames++;
 388         }
 389
 390         if (frames)
 391                 mt76_dma_kick_queue(dev, q);
 392
 393         spin_unlock_bh(&q->lock);
 394
 395         return frames;
 396 }
 397
 398 static void
 399 mt76_dma_rx_cleanup(struct mt76_dev *dev, struct mt76_queue *q)
 400 {
 401         struct page *page;
 402         void *buf;
 403         bool more;
 404
 405         spin_lock_bh(&q->lock);
 406         do {
 407                 buf = mt76_dma_dequeue(dev, q, true, NULL, NULL, &more);
 408                 if (!buf)
 409                         break;
 410
 411                 skb_free_frag(buf);
 412         } while (1);
 413         spin_unlock_bh(&q->lock);
 414
 415         if (!q->rx_page.va)
 416                 return;
 417
 418         page = virt_to_page(q->rx_page.va);
 419         __page_frag_cache_drain(page, q->rx_page.pagecnt_bias);
 420         memset(&q->rx_page, 0, sizeof(q->rx_page));
 421 }
 422
 423 static void
 424 mt76_dma_rx_reset(struct mt76_dev *dev, enum mt76_rxq_id qid)
 425 {
 426         struct mt76_queue *q = &dev->q_rx[qid];
 427         int i;
 428
 429         for (i = 0; i < q->ndesc; i++)
 430                 q->desc[i].ctrl &= ~cpu_to_le32(MT_DMA_CTL_DMA_DONE);
 431
 432         mt76_dma_rx_cleanup(dev, q);
 433         mt76_dma_sync_idx(dev, q);
 434         mt76_dma_rx_fill(dev, q);
 435
 436         if (!q->rx_head)
 437                 return;
 438
 439         dev_kfree_skb(q->rx_head);
 440         q->rx_head = NULL;
 441 }
 442
 443 static void
 444 mt76_add_fragment(struct mt76_dev *dev, struct mt76_queue *q, void *data,
 445                   int len, bool more)
 446 {
 447         struct page *page = virt_to_head_page(data);
 448         int offset = data - page_address(page);
 449         struct sk_buff *skb = q->rx_head;
 450
 451         offset += q->buf_offset;
 452         skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, offset, len,
 453                         q->buf_size);
 454
 455         if (more)
 456                 return;
 457
 458         q->rx_head = NULL;
 459         dev->drv->rx_skb(dev, q - dev->q_rx, skb);
 460 }
 461
 462 static int
 463 mt76_dma_rx_process(struct mt76_dev *dev, struct mt76_queue *q, int budget)
 464 {
 465         int len, data_len, done = 0;
 466         struct sk_buff *skb;
 467         unsigned char *data;
 468         bool more;
 469
 470         while (done < budget) {
 471                 u32 info;
 472
 473                 data = mt76_dma_dequeue(dev, q, false, &len, &info, &more);
 474                 if (!data)
 475                         break;
 476
 477                 if (q->rx_head)
 478                         data_len = q->buf_size;
 479                 else
 480                         data_len = SKB_WITH_OVERHEAD(q->buf_size);
 481
 482                 if (data_len < len + q->buf_offset) {
 483                         dev_kfree_skb(q->rx_head);
 484                         q->rx_head = NULL;
 485
 486                         skb_free_frag(data);
 487                         continue;
 488                 }
 489
 490                 if (q->rx_head) {
 491                         mt76_add_fragment(dev, q, data, len, more);
 492                         continue;
 493                 }
 494
 495                 skb = build_skb(data, q->buf_size);
 496                 if (!skb) {
 497                         skb_free_frag(data);
 498                         continue;
 499                 }
 500                 skb_reserve(skb, q->buf_offset);
 501
 502                 if (q == &dev->q_rx[MT_RXQ_MCU]) {
 503                         u32 *rxfce = (u32 *)skb->cb;
 504                         *rxfce = info;
 505                 }
 506
 507                 __skb_put(skb, len);
 508                 done++;
 509
 510                 if (more) {
 511                         q->rx_head = skb;
 512                         continue;
 513                 }
 514
 515                 dev->drv->rx_skb(dev, q - dev->q_rx, skb);
 516         }
 517
 518         mt76_dma_rx_fill(dev, q);
 519         return done;
 520 }
 521
 522 static int
 523 mt76_dma_rx_poll(struct napi_struct *napi, int budget)
 524 {
 525         struct mt76_dev *dev;
 526         int qid, done = 0, cur;
 527
 528         dev = container_of(napi->dev, struct mt76_dev, napi_dev);
 529         qid = napi - dev->napi;
 530
 531         rcu_read_lock();
 532
 533         do {
 534                 cur = mt76_dma_rx_process(dev, &dev->q_rx[qid], budget - done);
 535                 mt76_rx_poll_complete(dev, qid, napi);
 536                 done += cur;
 537         } while (cur && done < budget);
 538
 539         rcu_read_unlock();
 540
 541         if (done < budget && napi_complete(napi))
 542                 dev->drv->rx_poll_complete(dev, qid);
 543
 544         return done;
 545 }
 546
 547 static int
 548 mt76_dma_init(struct mt76_dev *dev)
 549 {
 550         int i;
 551
 552         init_dummy_netdev(&dev->napi_dev);
 553
 554         for (i = 0; i < ARRAY_SIZE(dev->q_rx); i++) {
 555                 netif_napi_add(&dev->napi_dev, &dev->napi[i], mt76_dma_rx_poll,
 556                                64);
 557                 mt76_dma_rx_fill(dev, &dev->q_rx[i]);
 558                 skb_queue_head_init(&dev->rx_skb[i]);
 559                 napi_enable(&dev->napi[i]);
 560         }
 561
 562         return 0;
 563 }
 564
 565 static const struct mt76_queue_ops mt76_dma_ops = {
 566         .init = mt76_dma_init,
 567         .alloc = mt76_dma_alloc_queue,
 568         .tx_queue_skb_raw = mt76_dma_tx_queue_skb_raw,
 569         .tx_queue_skb = mt76_dma_tx_queue_skb,
 570         .tx_cleanup = mt76_dma_tx_cleanup,
 571         .rx_reset = mt76_dma_rx_reset,
 572         .kick = mt76_dma_kick_queue,
 573 };
 574
 575 void mt76_dma_attach(struct mt76_dev *dev)
 576 {
 577         dev->queue_ops = &mt76_dma_ops;
 578 }
 579 EXPORT_SYMBOL_GPL(mt76_dma_attach);
 580
 581 void mt76_dma_cleanup(struct mt76_dev *dev)
 582 {
 583         int i;
 584
 585         netif_napi_del(&dev->tx_napi);
 586         for (i = 0; i < ARRAY_SIZE(dev->q_tx); i++)
 587                 mt76_dma_tx_cleanup(dev, i, true);
 588
 589         for (i = 0; i < ARRAY_SIZE(dev->q_rx); i++) {
 590                 netif_napi_del(&dev->napi[i]);
 591                 mt76_dma_rx_cleanup(dev, &dev->q_rx[i]);
 592         }
 593 }
 594 EXPORT_SYMBOL_GPL(mt76_dma_cleanup);