kernel/drivers/usb/host/whci/qset.c

   1 /*
   2  * Wireless Host Controller (WHC) qset management.
   3  *
   4  * Copyright (C) 2007 Cambridge Silicon Radio Ltd.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License version
   8  * 2 as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18 #include <linux/kernel.h>
  19 #include <linux/dma-mapping.h>
  20 #include <linux/slab.h>
  21 #include <linux/uwb/umc.h>
  22 #include <linux/usb.h>
  23
  24 #include "../../wusbcore/wusbhc.h"
  25
  26 #include "whcd.h"
  27
  28 struct whc_qset *qset_alloc(struct whc *whc, gfp_t mem_flags)
  29 {
  30         struct whc_qset *qset;
  31         dma_addr_t dma;
  32
  33         qset = dma_pool_alloc(whc->qset_pool, mem_flags, &dma);
  34         if (qset == NULL)
  35                 return NULL;
  36         memset(qset, 0, sizeof(struct whc_qset));
  37
  38         qset->qset_dma = dma;
  39         qset->whc = whc;
  40
  41         INIT_LIST_HEAD(&qset->list_node);
  42         INIT_LIST_HEAD(&qset->stds);
  43
  44         return qset;
  45 }
  46
  47 /**
  48  * qset_fill_qh - fill the static endpoint state in a qset's QHead
  49  * @qset: the qset whose QH needs initializing with static endpoint
  50  *        state
  51  * @urb:  an urb for a transfer to this endpoint
  52  */
  53 static void qset_fill_qh(struct whc *whc, struct whc_qset *qset, struct urb *urb)
  54 {
  55         struct usb_device *usb_dev = urb->dev;
  56         struct wusb_dev *wusb_dev = usb_dev->wusb_dev;
  57         struct usb_wireless_ep_comp_descriptor *epcd;
  58         bool is_out;
  59         uint8_t phy_rate;
  60
  61         is_out = usb_pipeout(urb->pipe);
  62
  63         qset->max_packet = le16_to_cpu(urb->ep->desc.wMaxPacketSize);
  64
  65         epcd = (struct usb_wireless_ep_comp_descriptor *)qset->ep->extra;
  66         if (epcd) {
  67                 qset->max_seq = epcd->bMaxSequence;
  68                 qset->max_burst = epcd->bMaxBurst;
  69         } else {
  70                 qset->max_seq = 2;
  71                 qset->max_burst = 1;
  72         }
  73
  74         /*
  75          * Initial PHY rate is 53.3 Mbit/s for control endpoints or
  76          * the maximum supported by the device for other endpoints
  77          * (unless limited by the user).
  78          */
  79         if (usb_pipecontrol(urb->pipe))
  80                 phy_rate = UWB_PHY_RATE_53;
  81         else {
  82                 uint16_t phy_rates;
  83
  84                 phy_rates = le16_to_cpu(wusb_dev->wusb_cap_descr->wPHYRates);
  85                 phy_rate = fls(phy_rates) - 1;
  86                 if (phy_rate > whc->wusbhc.phy_rate)
  87                         phy_rate = whc->wusbhc.phy_rate;
  88         }
  89
  90         qset->qh.info1 = cpu_to_le32(
  91                 QH_INFO1_EP(usb_pipeendpoint(urb->pipe))
  92                 | (is_out ? QH_INFO1_DIR_OUT : QH_INFO1_DIR_IN)
  93                 | usb_pipe_to_qh_type(urb->pipe)
  94                 | QH_INFO1_DEV_INFO_IDX(wusb_port_no_to_idx(usb_dev->portnum))
  95                 | QH_INFO1_MAX_PKT_LEN(qset->max_packet)
  96                 );
  97         qset->qh.info2 = cpu_to_le32(
  98                 QH_INFO2_BURST(qset->max_burst)
  99                 | QH_INFO2_DBP(0)
 100                 | QH_INFO2_MAX_COUNT(3)
 101                 | QH_INFO2_MAX_RETRY(3)
 102                 | QH_INFO2_MAX_SEQ(qset->max_seq - 1)
 103                 );
 104         /* FIXME: where can we obtain these Tx parameters from?  Why
 105          * doesn't the chip know what Tx power to use? It knows the Rx
 106          * strength and can presumably guess the Tx power required
 107          * from that? */
 108         qset->qh.info3 = cpu_to_le32(
 109                 QH_INFO3_TX_RATE(phy_rate)
 110                 | QH_INFO3_TX_PWR(0) /* 0 == max power */
 111                 );
 112
 113         qset->qh.cur_window = cpu_to_le32((1 << qset->max_burst) - 1);
 114 }
 115
 116 /**
 117  * qset_clear - clear fields in a qset so it may be reinserted into a
 118  * schedule.
 119  *
 120  * The sequence number and current window are not cleared (see
 121  * qset_reset()).
 122  */
 123 void qset_clear(struct whc *whc, struct whc_qset *qset)
 124 {
 125         qset->td_start = qset->td_end = qset->ntds = 0;
 126
 127         qset->qh.link = cpu_to_le64(QH_LINK_NTDS(8) | QH_LINK_T);
 128         qset->qh.status = qset->qh.status & QH_STATUS_SEQ_MASK;
 129         qset->qh.err_count = 0;
 130         qset->qh.scratch[0] = 0;
 131         qset->qh.scratch[1] = 0;
 132         qset->qh.scratch[2] = 0;
 133
 134         memset(&qset->qh.overlay, 0, sizeof(qset->qh.overlay));
 135
 136         init_completion(&qset->remove_complete);
 137 }
 138
 139 /**
 140  * qset_reset - reset endpoint state in a qset.
 141  *
 142  * Clears the sequence number and current window.  This qset must not
 143  * be in the ASL or PZL.
 144  */
 145 void qset_reset(struct whc *whc, struct whc_qset *qset)
 146 {
 147         qset->reset = 0;
 148
 149         qset->qh.status &= ~QH_STATUS_SEQ_MASK;
 150         qset->qh.cur_window = cpu_to_le32((1 << qset->max_burst) - 1);
 151 }
 152
 153 /**
 154  * get_qset - get the qset for an async endpoint
 155  *
 156  * A new qset is created if one does not already exist.
 157  */
 158 struct whc_qset *get_qset(struct whc *whc, struct urb *urb,
 159                                  gfp_t mem_flags)
 160 {
 161         struct whc_qset *qset;
 162
 163         qset = urb->ep->hcpriv;
 164         if (qset == NULL) {
 165                 qset = qset_alloc(whc, mem_flags);
 166                 if (qset == NULL)
 167                         return NULL;
 168
 169                 qset->ep = urb->ep;
 170                 urb->ep->hcpriv = qset;
 171                 qset_fill_qh(whc, qset, urb);
 172         }
 173         return qset;
 174 }
 175
 176 void qset_remove_complete(struct whc *whc, struct whc_qset *qset)
 177 {
 178         qset->remove = 0;
 179         list_del_init(&qset->list_node);
 180         complete(&qset->remove_complete);
 181 }
 182
 183 /**
 184  * qset_add_qtds - add qTDs for an URB to a qset
 185  *
 186  * Returns true if the list (ASL/PZL) must be updated because (for a
 187  * WHCI 0.95 controller) an activated qTD was pointed to be iCur.
 188  */
 189 enum whc_update qset_add_qtds(struct whc *whc, struct whc_qset *qset)
 190 {
 191         struct whc_std *std;
 192         enum whc_update update = 0;
 193
 194         list_for_each_entry(std, &qset->stds, list_node) {
 195                 struct whc_qtd *qtd;
 196                 uint32_t status;
 197
 198                 if (qset->ntds >= WHCI_QSET_TD_MAX
 199                     || (qset->pause_after_urb && std->urb != qset->pause_after_urb))
 200                         break;
 201
 202                 if (std->qtd)
 203                         continue; /* already has a qTD */
 204
 205                 qtd = std->qtd = &qset->qtd[qset->td_end];
 206
 207                 /* Fill in setup bytes for control transfers. */
 208                 if (usb_pipecontrol(std->urb->pipe))
 209                         memcpy(qtd->setup, std->urb->setup_packet, 8);
 210
 211                 status = QTD_STS_ACTIVE | QTD_STS_LEN(std->len);
 212
 213                 if (whc_std_last(std) && usb_pipeout(std->urb->pipe))
 214                         status |= QTD_STS_LAST_PKT;
 215
 216                 /*
 217                  * For an IN transfer the iAlt field should be set so
 218                  * the h/w will automatically advance to the next
 219                  * transfer. However, if there are 8 or more TDs
 220                  * remaining in this transfer then iAlt cannot be set
 221                  * as it could point to somewhere in this transfer.
 222                  */
 223                 if (std->ntds_remaining < WHCI_QSET_TD_MAX) {
 224                         int ialt;
 225                         ialt = (qset->td_end + std->ntds_remaining) % WHCI_QSET_TD_MAX;
 226                         status |= QTD_STS_IALT(ialt);
 227                 } else if (usb_pipein(std->urb->pipe))
 228                         qset->pause_after_urb = std->urb;
 229
 230                 if (std->num_pointers)
 231                         qtd->options = cpu_to_le32(QTD_OPT_IOC);
 232                 else
 233                         qtd->options = cpu_to_le32(QTD_OPT_IOC | QTD_OPT_SMALL);
 234                 qtd->page_list_ptr = cpu_to_le64(std->dma_addr);
 235
 236                 qtd->status = cpu_to_le32(status);
 237
 238                 if (QH_STATUS_TO_ICUR(qset->qh.status) == qset->td_end)
 239                         update = WHC_UPDATE_UPDATED;
 240
 241                 if (++qset->td_end >= WHCI_QSET_TD_MAX)
 242                         qset->td_end = 0;
 243                 qset->ntds++;
 244         }
 245
 246         return update;
 247 }
 248
 249 /**
 250  * qset_remove_qtd - remove the first qTD from a qset.
 251  *
 252  * The qTD might be still active (if it's part of a IN URB that
 253  * resulted in a short read) so ensure it's deactivated.
 254  */
 255 static void qset_remove_qtd(struct whc *whc, struct whc_qset *qset)
 256 {
 257         qset->qtd[qset->td_start].status = 0;
 258
 259         if (++qset->td_start >= WHCI_QSET_TD_MAX)
 260                 qset->td_start = 0;
 261         qset->ntds--;
 262 }
 263
 264 static void qset_copy_bounce_to_sg(struct whc *whc, struct whc_std *std)
 265 {
 266         struct scatterlist *sg;
 267         void *bounce;
 268         size_t remaining, offset;
 269
 270         bounce = std->bounce_buf;
 271         remaining = std->len;
 272
 273         sg = std->bounce_sg;
 274         offset = std->bounce_offset;
 275
 276         while (remaining) {
 277                 size_t len;
 278
 279                 len = min(sg->length - offset, remaining);
 280                 memcpy(sg_virt(sg) + offset, bounce, len);
 281
 282                 bounce += len;
 283                 remaining -= len;
 284
 285                 offset += len;
 286                 if (offset >= sg->length) {
 287                         sg = sg_next(sg);
 288                         offset = 0;
 289                 }
 290         }
 291
 292 }
 293
 294 /**
 295  * qset_free_std - remove an sTD and free it.
 296  * @whc: the WHCI host controller
 297  * @std: the sTD to remove and free.
 298  */
 299 void qset_free_std(struct whc *whc, struct whc_std *std)
 300 {
 301         list_del(&std->list_node);
 302         if (std->bounce_buf) {
 303                 bool is_out = usb_pipeout(std->urb->pipe);
 304                 dma_addr_t dma_addr;
 305
 306                 if (std->num_pointers)
 307                         dma_addr = le64_to_cpu(std->pl_virt[0].buf_ptr);
 308                 else
 309                         dma_addr = std->dma_addr;
 310
 311                 dma_unmap_single(whc->wusbhc.dev, dma_addr,
 312                                  std->len, is_out ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
 313                 if (!is_out)
 314                         qset_copy_bounce_to_sg(whc, std);
 315                 kfree(std->bounce_buf);
 316         }
 317         if (std->pl_virt) {
 318                 if (std->dma_addr)
 319                         dma_unmap_single(whc->wusbhc.dev, std->dma_addr,
 320                                          std->num_pointers * sizeof(struct whc_page_list_entry),
 321                                          DMA_TO_DEVICE);
 322                 kfree(std->pl_virt);
 323                 std->pl_virt = NULL;
 324         }
 325         kfree(std);
 326 }
 327
 328 /**
 329  * qset_remove_qtds - remove an URB's qTDs (and sTDs).
 330  */
 331 static void qset_remove_qtds(struct whc *whc, struct whc_qset *qset,
 332                              struct urb *urb)
 333 {
 334         struct whc_std *std, *t;
 335
 336         list_for_each_entry_safe(std, t, &qset->stds, list_node) {
 337                 if (std->urb != urb)
 338                         break;
 339                 if (std->qtd != NULL)
 340                         qset_remove_qtd(whc, qset);
 341                 qset_free_std(whc, std);
 342         }
 343 }
 344
 345 /**
 346  * qset_free_stds - free any remaining sTDs for an URB.
 347  */
 348 static void qset_free_stds(struct whc_qset *qset, struct urb *urb)
 349 {
 350         struct whc_std *std, *t;
 351
 352         list_for_each_entry_safe(std, t, &qset->stds, list_node) {
 353                 if (std->urb == urb)
 354                         qset_free_std(qset->whc, std);
 355         }
 356 }
 357
 358 static int qset_fill_page_list(struct whc *whc, struct whc_std *std, gfp_t mem_flags)
 359 {
 360         dma_addr_t dma_addr = std->dma_addr;
 361         dma_addr_t sp, ep;
 362         size_t pl_len;
 363         int p;
 364
 365         /* Short buffers don't need a page list. */
 366         if (std->len <= WHCI_PAGE_SIZE) {
 367                 std->num_pointers = 0;
 368                 return 0;
 369         }
 370
 371         sp = dma_addr & ~(WHCI_PAGE_SIZE-1);
 372         ep = dma_addr + std->len;
 373         std->num_pointers = DIV_ROUND_UP(ep - sp, WHCI_PAGE_SIZE);
 374
 375         pl_len = std->num_pointers * sizeof(struct whc_page_list_entry);
 376         std->pl_virt = kmalloc(pl_len, mem_flags);
 377         if (std->pl_virt == NULL)
 378                 return -ENOMEM;
 379         std->dma_addr = dma_map_single(whc->wusbhc.dev, std->pl_virt, pl_len, DMA_TO_DEVICE);
 380         if (dma_mapping_error(whc->wusbhc.dev, std->dma_addr)) {
 381                 kfree(std->pl_virt);
 382                 return -EFAULT;
 383         }
 384
 385         for (p = 0; p < std->num_pointers; p++) {
 386                 std->pl_virt[p].buf_ptr = cpu_to_le64(dma_addr);
 387                 dma_addr = (dma_addr + WHCI_PAGE_SIZE) & ~(WHCI_PAGE_SIZE-1);
 388         }
 389
 390         return 0;
 391 }
 392
 393 /**
 394  * urb_dequeue_work - executes asl/pzl update and gives back the urb to the system.
 395  */
 396 static void urb_dequeue_work(struct work_struct *work)
 397 {
 398         struct whc_urb *wurb = container_of(work, struct whc_urb, dequeue_work);
 399         struct whc_qset *qset = wurb->qset;
 400         struct whc *whc = qset->whc;
 401         unsigned long flags;
 402
 403         if (wurb->is_async == true)
 404                 asl_update(whc, WUSBCMD_ASYNC_UPDATED
 405                            | WUSBCMD_ASYNC_SYNCED_DB
 406                            | WUSBCMD_ASYNC_QSET_RM);
 407         else
 408                 pzl_update(whc, WUSBCMD_PERIODIC_UPDATED
 409                            | WUSBCMD_PERIODIC_SYNCED_DB
 410                            | WUSBCMD_PERIODIC_QSET_RM);
 411
 412         spin_lock_irqsave(&whc->lock, flags);
 413         qset_remove_urb(whc, qset, wurb->urb, wurb->status);
 414         spin_unlock_irqrestore(&whc->lock, flags);
 415 }
 416
 417 static struct whc_std *qset_new_std(struct whc *whc, struct whc_qset *qset,
 418                                     struct urb *urb, gfp_t mem_flags)
 419 {
 420         struct whc_std *std;
 421
 422         std = kzalloc(sizeof(struct whc_std), mem_flags);
 423         if (std == NULL)
 424                 return NULL;
 425
 426         std->urb = urb;
 427         std->qtd = NULL;
 428
 429         INIT_LIST_HEAD(&std->list_node);
 430         list_add_tail(&std->list_node, &qset->stds);
 431
 432         return std;
 433 }
 434
 435 static int qset_add_urb_sg(struct whc *whc, struct whc_qset *qset, struct urb *urb,
 436                            gfp_t mem_flags)
 437 {
 438         size_t remaining;
 439         struct scatterlist *sg;
 440         int i;
 441         int ntds = 0;
 442         struct whc_std *std = NULL;
 443         struct whc_page_list_entry *new_pl_virt;
 444         dma_addr_t prev_end = 0;
 445         size_t pl_len;
 446         int p = 0;
 447
 448         remaining = urb->transfer_buffer_length;
 449
 450         for_each_sg(urb->sg, sg, urb->num_mapped_sgs, i) {
 451                 dma_addr_t dma_addr;
 452                 size_t dma_remaining;
 453                 dma_addr_t sp, ep;
 454                 int num_pointers;
 455
 456                 if (remaining == 0) {
 457                         break;
 458                 }
 459
 460                 dma_addr = sg_dma_address(sg);
 461                 dma_remaining = min_t(size_t, sg_dma_len(sg), remaining);
 462
 463                 while (dma_remaining) {
 464                         size_t dma_len;
 465
 466                         /*
 467                          * We can use the previous std (if it exists) provided that:
 468                          * - the previous one ended on a page boundary.
 469                          * - the current one begins on a page boundary.
 470                          * - the previous one isn't full.
 471                          *
 472                          * If a new std is needed but the previous one
 473                          * was not a whole number of packets then this
 474                          * sg list cannot be mapped onto multiple
 475                          * qTDs.  Return an error and let the caller
 476                          * sort it out.
 477                          */
 478                         if (!std
 479                             || (prev_end & (WHCI_PAGE_SIZE-1))
 480                             || (dma_addr & (WHCI_PAGE_SIZE-1))
 481                             || std->len + WHCI_PAGE_SIZE > QTD_MAX_XFER_SIZE) {
 482                                 if (std && std->len % qset->max_packet != 0)
 483                                         return -EINVAL;
 484                                 std = qset_new_std(whc, qset, urb, mem_flags);
 485                                 if (std == NULL) {
 486                                         return -ENOMEM;
 487                                 }
 488                                 ntds++;
 489                                 p = 0;
 490                         }
 491
 492                         dma_len = dma_remaining;
 493
 494                         /*
 495                          * If the remainder of this element doesn't
 496                          * fit in a single qTD, limit the qTD to a
 497                          * whole number of packets.  This allows the
 498                          * remainder to go into the next qTD.
 499                          */
 500                         if (std->len + dma_len > QTD_MAX_XFER_SIZE) {
 501                                 dma_len = (QTD_MAX_XFER_SIZE / qset->max_packet)
 502                                         * qset->max_packet - std->len;
 503                         }
 504
 505                         std->len += dma_len;
 506                         std->ntds_remaining = -1; /* filled in later */
 507
 508                         sp = dma_addr & ~(WHCI_PAGE_SIZE-1);
 509                         ep = dma_addr + dma_len;
 510                         num_pointers = DIV_ROUND_UP(ep - sp, WHCI_PAGE_SIZE);
 511                         std->num_pointers += num_pointers;
 512
 513                         pl_len = std->num_pointers * sizeof(struct whc_page_list_entry);
 514
 515                         new_pl_virt = krealloc(std->pl_virt, pl_len, mem_flags);
 516                         if (new_pl_virt == NULL) {
 517                                 kfree(std->pl_virt);
 518                                 std->pl_virt = NULL;
 519                                 return -ENOMEM;
 520                         }
 521                         std->pl_virt = new_pl_virt;
 522
 523                         for (;p < std->num_pointers; p++) {
 524                                 std->pl_virt[p].buf_ptr = cpu_to_le64(dma_addr);
 525                                 dma_addr = (dma_addr + WHCI_PAGE_SIZE) & ~(WHCI_PAGE_SIZE-1);
 526                         }
 527
 528                         prev_end = dma_addr = ep;
 529                         dma_remaining -= dma_len;
 530                         remaining -= dma_len;
 531                 }
 532         }
 533
 534         /* Now the number of stds is know, go back and fill in
 535            std->ntds_remaining. */
 536         list_for_each_entry(std, &qset->stds, list_node) {
 537                 if (std->ntds_remaining == -1) {
 538                         pl_len = std->num_pointers * sizeof(struct whc_page_list_entry);
 539                         std->ntds_remaining = ntds--;
 540                         std->dma_addr = dma_map_single(whc->wusbhc.dev, std->pl_virt,
 541                                                        pl_len, DMA_TO_DEVICE);
 542                 }
 543         }
 544         return 0;
 545 }
 546
 547 /**
 548  * qset_add_urb_sg_linearize - add an urb with sg list, copying the data
 549  *
 550  * If the URB contains an sg list whose elements cannot be directly
 551  * mapped to qTDs then the data must be transferred via bounce
 552  * buffers.
 553  */
 554 static int qset_add_urb_sg_linearize(struct whc *whc, struct whc_qset *qset,
 555                                      struct urb *urb, gfp_t mem_flags)
 556 {
 557         bool is_out = usb_pipeout(urb->pipe);
 558         size_t max_std_len;
 559         size_t remaining;
 560         int ntds = 0;
 561         struct whc_std *std = NULL;
 562         void *bounce = NULL;
 563         struct scatterlist *sg;
 564         int i;
 565
 566         /* limit maximum bounce buffer to 16 * 3.5 KiB ~= 28 k */
 567         max_std_len = qset->max_burst * qset->max_packet;
 568
 569         remaining = urb->transfer_buffer_length;
 570
 571         for_each_sg(urb->sg, sg, urb->num_mapped_sgs, i) {
 572                 size_t len;
 573                 size_t sg_remaining;
 574                 void *orig;
 575
 576                 if (remaining == 0) {
 577                         break;
 578                 }
 579
 580                 sg_remaining = min_t(size_t, remaining, sg->length);
 581                 orig = sg_virt(sg);
 582
 583                 while (sg_remaining) {
 584                         if (!std || std->len == max_std_len) {
 585                                 std = qset_new_std(whc, qset, urb, mem_flags);
 586                                 if (std == NULL)
 587                                         return -ENOMEM;
 588                                 std->bounce_buf = kmalloc(max_std_len, mem_flags);
 589                                 if (std->bounce_buf == NULL)
 590                                         return -ENOMEM;
 591                                 std->bounce_sg = sg;
 592                                 std->bounce_offset = orig - sg_virt(sg);
 593                                 bounce = std->bounce_buf;
 594                                 ntds++;
 595                         }
 596
 597                         len = min(sg_remaining, max_std_len - std->len);
 598
 599                         if (is_out)
 600                                 memcpy(bounce, orig, len);
 601
 602                         std->len += len;
 603                         std->ntds_remaining = -1; /* filled in later */
 604
 605                         bounce += len;
 606                         orig += len;
 607                         sg_remaining -= len;
 608                         remaining -= len;
 609                 }
 610         }
 611
 612         /*
 613          * For each of the new sTDs, map the bounce buffers, create
 614          * page lists (if necessary), and fill in std->ntds_remaining.
 615          */
 616         list_for_each_entry(std, &qset->stds, list_node) {
 617                 if (std->ntds_remaining != -1)
 618                         continue;
 619
 620                 std->dma_addr = dma_map_single(&whc->umc->dev, std->bounce_buf, std->len,
 621                                                is_out ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
 622
 623                 if (qset_fill_page_list(whc, std, mem_flags) < 0)
 624                         return -ENOMEM;
 625
 626                 std->ntds_remaining = ntds--;
 627         }
 628
 629         return 0;
 630 }
 631
 632 /**
 633  * qset_add_urb - add an urb to the qset's queue.
 634  *
 635  * The URB is chopped into sTDs, one for each qTD that will required.
 636  * At least one qTD (and sTD) is required even if the transfer has no
 637  * data (e.g., for some control transfers).
 638  */
 639 int qset_add_urb(struct whc *whc, struct whc_qset *qset, struct urb *urb,
 640         gfp_t mem_flags)
 641 {
 642         struct whc_urb *wurb;
 643         int remaining = urb->transfer_buffer_length;
 644         u64 transfer_dma = urb->transfer_dma;
 645         int ntds_remaining;
 646         int ret;
 647
 648         wurb = kzalloc(sizeof(struct whc_urb), mem_flags);
 649         if (wurb == NULL)
 650                 goto err_no_mem;
 651         urb->hcpriv = wurb;
 652         wurb->qset = qset;
 653         wurb->urb = urb;
 654         INIT_WORK(&wurb->dequeue_work, urb_dequeue_work);
 655
 656         if (urb->num_sgs) {
 657                 ret = qset_add_urb_sg(whc, qset, urb, mem_flags);
 658                 if (ret == -EINVAL) {
 659                         qset_free_stds(qset, urb);
 660                         ret = qset_add_urb_sg_linearize(whc, qset, urb, mem_flags);
 661                 }
 662                 if (ret < 0)
 663                         goto err_no_mem;
 664                 return 0;
 665         }
 666
 667         ntds_remaining = DIV_ROUND_UP(remaining, QTD_MAX_XFER_SIZE);
 668         if (ntds_remaining == 0)
 669                 ntds_remaining = 1;
 670
 671         while (ntds_remaining) {
 672                 struct whc_std *std;
 673                 size_t std_len;
 674
 675                 std_len = remaining;
 676                 if (std_len > QTD_MAX_XFER_SIZE)
 677                         std_len = QTD_MAX_XFER_SIZE;
 678
 679                 std = qset_new_std(whc, qset, urb, mem_flags);
 680                 if (std == NULL)
 681                         goto err_no_mem;
 682
 683                 std->dma_addr = transfer_dma;
 684                 std->len = std_len;
 685                 std->ntds_remaining = ntds_remaining;
 686
 687                 if (qset_fill_page_list(whc, std, mem_flags) < 0)
 688                         goto err_no_mem;
 689
 690                 ntds_remaining--;
 691                 remaining -= std_len;
 692                 transfer_dma += std_len;
 693         }
 694
 695         return 0;
 696
 697 err_no_mem:
 698         qset_free_stds(qset, urb);
 699         return -ENOMEM;
 700 }
 701
 702 /**
 703  * qset_remove_urb - remove an URB from the urb queue.
 704  *
 705  * The URB is returned to the USB subsystem.
 706  */
 707 void qset_remove_urb(struct whc *whc, struct whc_qset *qset,
 708                             struct urb *urb, int status)
 709 {
 710         struct wusbhc *wusbhc = &whc->wusbhc;
 711         struct whc_urb *wurb = urb->hcpriv;
 712
 713         usb_hcd_unlink_urb_from_ep(&wusbhc->usb_hcd, urb);
 714         /* Drop the lock as urb->complete() may enqueue another urb. */
 715         spin_unlock(&whc->lock);
 716         wusbhc_giveback_urb(wusbhc, urb, status);
 717         spin_lock(&whc->lock);
 718
 719         kfree(wurb);
 720 }
 721
 722 /**
 723  * get_urb_status_from_qtd - get the completed urb status from qTD status
 724  * @urb:    completed urb
 725  * @status: qTD status
 726  */
 727 static int get_urb_status_from_qtd(struct urb *urb, u32 status)
 728 {
 729         if (status & QTD_STS_HALTED) {
 730                 if (status & QTD_STS_DBE)
 731                         return usb_pipein(urb->pipe) ? -ENOSR : -ECOMM;
 732                 else if (status & QTD_STS_BABBLE)
 733                         return -EOVERFLOW;
 734                 else if (status & QTD_STS_RCE)
 735                         return -ETIME;
 736                 return -EPIPE;
 737         }
 738         if (usb_pipein(urb->pipe)
 739             && (urb->transfer_flags & URB_SHORT_NOT_OK)
 740             && urb->actual_length < urb->transfer_buffer_length)
 741                 return -EREMOTEIO;
 742         return 0;
 743 }
 744
 745 /**
 746  * process_inactive_qtd - process an inactive (but not halted) qTD.
 747  *
 748  * Update the urb with the transfer bytes from the qTD, if the urb is
 749  * completely transferred or (in the case of an IN only) the LPF is
 750  * set, then the transfer is complete and the urb should be returned
 751  * to the system.
 752  */
 753 void process_inactive_qtd(struct whc *whc, struct whc_qset *qset,
 754                                  struct whc_qtd *qtd)
 755 {
 756         struct whc_std *std = list_first_entry(&qset->stds, struct whc_std, list_node);
 757         struct urb *urb = std->urb;
 758         uint32_t status;
 759         bool complete;
 760
 761         status = le32_to_cpu(qtd->status);
 762
 763         urb->actual_length += std->len - QTD_STS_TO_LEN(status);
 764
 765         if (usb_pipein(urb->pipe) && (status & QTD_STS_LAST_PKT))
 766                 complete = true;
 767         else
 768                 complete = whc_std_last(std);
 769
 770         qset_remove_qtd(whc, qset);
 771         qset_free_std(whc, std);
 772
 773         /*
 774          * Transfers for this URB are complete?  Then return it to the
 775          * USB subsystem.
 776          */
 777         if (complete) {
 778                 qset_remove_qtds(whc, qset, urb);
 779                 qset_remove_urb(whc, qset, urb, get_urb_status_from_qtd(urb, status));
 780
 781                 /*
 782                  * If iAlt isn't valid then the hardware didn't
 783                  * advance iCur. Adjust the start and end pointers to
 784                  * match iCur.
 785                  */
 786                 if (!(status & QTD_STS_IALT_VALID))
 787                         qset->td_start = qset->td_end
 788                                 = QH_STATUS_TO_ICUR(le16_to_cpu(qset->qh.status));
 789                 qset->pause_after_urb = NULL;
 790         }
 791 }
 792
 793 /**
 794  * process_halted_qtd - process a qset with a halted qtd
 795  *
 796  * Remove all the qTDs for the failed URB and return the failed URB to
 797  * the USB subsystem.  Then remove all other qTDs so the qset can be
 798  * removed.
 799  *
 800  * FIXME: this is the point where rate adaptation can be done.  If a
 801  * transfer failed because it exceeded the maximum number of retries
 802  * then it could be reactivated with a slower rate without having to
 803  * remove the qset.
 804  */
 805 void process_halted_qtd(struct whc *whc, struct whc_qset *qset,
 806                                struct whc_qtd *qtd)
 807 {
 808         struct whc_std *std = list_first_entry(&qset->stds, struct whc_std, list_node);
 809         struct urb *urb = std->urb;
 810         int urb_status;
 811
 812         urb_status = get_urb_status_from_qtd(urb, le32_to_cpu(qtd->status));
 813
 814         qset_remove_qtds(whc, qset, urb);
 815         qset_remove_urb(whc, qset, urb, urb_status);
 816
 817         list_for_each_entry(std, &qset->stds, list_node) {
 818                 if (qset->ntds == 0)
 819                         break;
 820                 qset_remove_qtd(whc, qset);
 821                 std->qtd = NULL;
 822         }
 823
 824         qset->remove = 1;
 825 }
 826
 827 void qset_free(struct whc *whc, struct whc_qset *qset)
 828 {
 829         dma_pool_free(whc->qset_pool, qset, qset->qset_dma);
 830 }
 831
 832 /**
 833  * qset_delete - wait for a qset to be unused, then free it.
 834  */
 835 void qset_delete(struct whc *whc, struct whc_qset *qset)
 836 {
 837         wait_for_completion(&qset->remove_complete);
 838         qset_free(whc, qset);
 839 }