Logo Search packages:      
Sourcecode: linux version File versions  Download package

ehci-q.c

/*
 * Copyright (C) 2001-2004 by David Brownell
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* this file is part of ehci-hcd.c */

/*-------------------------------------------------------------------------*/

/*
 * EHCI hardware queue manipulation ... the core.  QH/QTD manipulation.
 *
 * Control, bulk, and interrupt traffic all use "qh" lists.  They list "qtd"
 * entries describing USB transactions, max 16-20kB/entry (with 4kB-aligned
 * buffers needed for the larger number).  We use one QH per endpoint, queue
 * multiple urbs (all three types) per endpoint.  URBs may need several qtds.
 *
 * ISO traffic uses "ISO TD" (itd, and sitd) records, and (along with
 * interrupts) needs careful scheduling.  Performance improvements can be
 * an ongoing challenge.  That's in "ehci-sched.c".
 *
 * USB 1.1 devices are handled (a) by "companion" OHCI or UHCI root hubs,
 * or otherwise through transaction translators (TTs) in USB 2.0 hubs using
 * (b) special fields in qh entries or (c) split iso entries.  TTs will
 * buffer low/full speed data so the host collects it at high speed.
 */

/*-------------------------------------------------------------------------*/

/* fill a qtd, returning how much of the buffer we were able to queue up */

static int
qtd_fill(struct ehci_hcd *ehci, struct ehci_qtd *qtd, dma_addr_t buf,
              size_t len, int token, int maxpacket)
{
      int   i, count;
      u64   addr = buf;

      /* one buffer entry per 4K ... first might be short or unaligned */
      qtd->hw_buf[0] = cpu_to_hc32(ehci, (u32)addr);
      qtd->hw_buf_hi[0] = cpu_to_hc32(ehci, (u32)(addr >> 32));
      count = 0x1000 - (buf & 0x0fff);    /* rest of that page */
      if (likely (len < count))           /* ... iff needed */
            count = len;
      else {
            buf +=  0x1000;
            buf &= ~0x0fff;

            /* per-qtd limit: from 16K to 20K (best alignment) */
            for (i = 1; count < len && i < 5; i++) {
                  addr = buf;
                  qtd->hw_buf[i] = cpu_to_hc32(ehci, (u32)addr);
                  qtd->hw_buf_hi[i] = cpu_to_hc32(ehci,
                              (u32)(addr >> 32));
                  buf += 0x1000;
                  if ((count + 0x1000) < len)
                        count += 0x1000;
                  else
                        count = len;
            }

            /* short packets may only terminate transfers */
            if (count != len)
                  count -= (count % maxpacket);
      }
      qtd->hw_token = cpu_to_hc32(ehci, (count << 16) | token);
      qtd->length = count;

      return count;
}

/*-------------------------------------------------------------------------*/

static inline void
qh_update (struct ehci_hcd *ehci, struct ehci_qh *qh, struct ehci_qtd *qtd)
{
      /* writes to an active overlay are unsafe */
      BUG_ON(qh->qh_state != QH_STATE_IDLE);

      qh->hw_qtd_next = QTD_NEXT(ehci, qtd->qtd_dma);
      qh->hw_alt_next = EHCI_LIST_END(ehci);

      /* Except for control endpoints, we make hardware maintain data
       * toggle (like OHCI) ... here (re)initialize the toggle in the QH,
       * and set the pseudo-toggle in udev. Only usb_clear_halt() will
       * ever clear it.
       */
      if (!(qh->hw_info1 & cpu_to_hc32(ehci, 1 << 14))) {
            unsigned    is_out, epnum;

            is_out = !(qtd->hw_token & cpu_to_hc32(ehci, 1 << 8));
            epnum = (hc32_to_cpup(ehci, &qh->hw_info1) >> 8) & 0x0f;
            if (unlikely (!usb_gettoggle (qh->dev, epnum, is_out))) {
                  qh->hw_token &= ~cpu_to_hc32(ehci, QTD_TOGGLE);
                  usb_settoggle (qh->dev, epnum, is_out, 1);
            }
      }

      /* HC must see latest qtd and qh data before we clear ACTIVE+HALT */
      wmb ();
      qh->hw_token &= cpu_to_hc32(ehci, QTD_TOGGLE | QTD_STS_PING);
}

/* if it weren't for a common silicon quirk (writing the dummy into the qh
 * overlay, so qh->hw_token wrongly becomes inactive/halted), only fault
 * recovery (including urb dequeue) would need software changes to a QH...
 */
static void
qh_refresh (struct ehci_hcd *ehci, struct ehci_qh *qh)
{
      struct ehci_qtd *qtd;

      if (list_empty (&qh->qtd_list))
            qtd = qh->dummy;
      else {
            qtd = list_entry (qh->qtd_list.next,
                        struct ehci_qtd, qtd_list);
            /* first qtd may already be partially processed */
            if (cpu_to_hc32(ehci, qtd->qtd_dma) == qh->hw_current)
                  qtd = NULL;
      }

      if (qtd)
            qh_update (ehci, qh, qtd);
}

/*-------------------------------------------------------------------------*/

static int qtd_copy_status (
      struct ehci_hcd *ehci,
      struct urb *urb,
      size_t length,
      u32 token
)
{
      int   status = -EINPROGRESS;

      /* count IN/OUT bytes, not SETUP (even short packets) */
      if (likely (QTD_PID (token) != 2))
            urb->actual_length += length - QTD_LENGTH (token);

      /* don't modify error codes */
      if (unlikely(urb->unlinked))
            return status;

      /* force cleanup after short read; not always an error */
      if (unlikely (IS_SHORT_READ (token)))
            status = -EREMOTEIO;

      /* serious "can't proceed" faults reported by the hardware */
      if (token & QTD_STS_HALT) {
            if (token & QTD_STS_BABBLE) {
                  /* FIXME "must" disable babbling device's port too */
                  status = -EOVERFLOW;
            } else if (token & QTD_STS_MMF) {
                  /* fs/ls interrupt xfer missed the complete-split */
                  status = -EPROTO;
            } else if (token & QTD_STS_DBE) {
                  status = (QTD_PID (token) == 1) /* IN ? */
                        ? -ENOSR  /* hc couldn't read data */
                        : -ECOMM; /* hc couldn't write data */
            } else if (token & QTD_STS_XACT) {
                  /* timeout, bad crc, wrong PID, etc; retried */
                  if (QTD_CERR (token))
                        status = -EPIPE;
                  else {
                        ehci_dbg (ehci, "devpath %s ep%d%s 3strikes\n",
                              urb->dev->devpath,
                              usb_pipeendpoint (urb->pipe),
                              usb_pipein (urb->pipe) ? "in" : "out");
                        status = -EPROTO;
                  }
            /* CERR nonzero + no errors + halt --> stall */
            } else if (QTD_CERR (token))
                  status = -EPIPE;
            else  /* unknown */
                  status = -EPROTO;

            ehci_vdbg (ehci,
                  "dev%d ep%d%s qtd token %08x --> status %d\n",
                  usb_pipedevice (urb->pipe),
                  usb_pipeendpoint (urb->pipe),
                  usb_pipein (urb->pipe) ? "in" : "out",
                  token, status);

            /* if async CSPLIT failed, try cleaning out the TT buffer */
            if (status != -EPIPE
                        && urb->dev->tt && !usb_pipeint (urb->pipe)
                        && ((token & QTD_STS_MMF) != 0
                              || QTD_CERR(token) == 0)
                        && (!ehci_is_TDI(ehci)
                                  || urb->dev->tt->hub !=
                                 ehci_to_hcd(ehci)->self.root_hub)) {
#ifdef DEBUG
                  struct usb_device *tt = urb->dev->tt->hub;
                  dev_dbg (&tt->dev,
                        "clear tt buffer port %d, a%d ep%d t%08x\n",
                        urb->dev->ttport, urb->dev->devnum,
                        usb_pipeendpoint (urb->pipe), token);
#endif /* DEBUG */
                  usb_hub_tt_clear_buffer (urb->dev, urb->pipe);
            }
      }

      return status;
}

static void
ehci_urb_done(struct ehci_hcd *ehci, struct urb *urb, int status)
__releases(ehci->lock)
__acquires(ehci->lock)
{
      if (likely (urb->hcpriv != NULL)) {
            struct ehci_qh    *qh = (struct ehci_qh *) urb->hcpriv;

            /* S-mask in a QH means it's an interrupt urb */
            if ((qh->hw_info2 & cpu_to_hc32(ehci, QH_SMASK)) != 0) {

                  /* ... update hc-wide periodic stats (for usbfs) */
                  ehci_to_hcd(ehci)->self.bandwidth_int_reqs--;
            }
            qh_put (qh);
      }

      if (unlikely(urb->unlinked)) {
            COUNT(ehci->stats.unlink);
      } else {
            if (likely(status == -EINPROGRESS))
                  status = 0;
            COUNT(ehci->stats.complete);
      }

#ifdef EHCI_URB_TRACE
      ehci_dbg (ehci,
            "%s %s urb %p ep%d%s status %d len %d/%d\n",
            __FUNCTION__, urb->dev->devpath, urb,
            usb_pipeendpoint (urb->pipe),
            usb_pipein (urb->pipe) ? "in" : "out",
            status,
            urb->actual_length, urb->transfer_buffer_length);
#endif

      /* complete() can reenter this HCD */
      usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
      spin_unlock (&ehci->lock);
      usb_hcd_giveback_urb(ehci_to_hcd(ehci), urb, status);
      spin_lock (&ehci->lock);
}

static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh);
static void unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh);

static void intr_deschedule (struct ehci_hcd *ehci, struct ehci_qh *qh);
static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh);

/*
 * Process and free completed qtds for a qh, returning URBs to drivers.
 * Chases up to qh->hw_current.  Returns number of completions called,
 * indicating how much "real" work we did.
 */
static unsigned
qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
{
      struct ehci_qtd         *last = NULL, *end = qh->dummy;
      struct list_head  *entry, *tmp;
      int               last_status = -EINPROGRESS;
      int               stopped;
      unsigned          count = 0;
      int               do_status = 0;
      u8                state;
      u32               halt = HALT_BIT(ehci);

      if (unlikely (list_empty (&qh->qtd_list)))
            return count;

      /* completions (or tasks on other cpus) must never clobber HALT
       * till we've gone through and cleaned everything up, even when
       * they add urbs to this qh's queue or mark them for unlinking.
       *
       * NOTE:  unlinking expects to be done in queue order.
       */
      state = qh->qh_state;
      qh->qh_state = QH_STATE_COMPLETING;
      stopped = (state == QH_STATE_IDLE);

      /* remove de-activated QTDs from front of queue.
       * after faults (including short reads), cleanup this urb
       * then let the queue advance.
       * if queue is stopped, handles unlinks.
       */
      list_for_each_safe (entry, tmp, &qh->qtd_list) {
            struct ehci_qtd   *qtd;
            struct urb  *urb;
            u32         token = 0;
            int         qtd_status;

            qtd = list_entry (entry, struct ehci_qtd, qtd_list);
            urb = qtd->urb;

            /* clean up any state from previous QTD ...*/
            if (last) {
                  if (likely (last->urb != urb)) {
                        ehci_urb_done(ehci, last->urb, last_status);
                        count++;
                  }
                  ehci_qtd_free (ehci, last);
                  last = NULL;
                  last_status = -EINPROGRESS;
            }

            /* ignore urbs submitted during completions we reported */
            if (qtd == end)
                  break;

            /* hardware copies qtd out of qh overlay */
            rmb ();
            token = hc32_to_cpu(ehci, qtd->hw_token);

            /* always clean up qtds the hc de-activated */
            if ((token & QTD_STS_ACTIVE) == 0) {

                  if ((token & QTD_STS_HALT) != 0) {
                        stopped = 1;

                  /* magic dummy for some short reads; qh won't advance.
                   * that silicon quirk can kick in with this dummy too.
                   */
                  } else if (IS_SHORT_READ (token)
                              && !(qtd->hw_alt_next
                                    & EHCI_LIST_END(ehci))) {
                        stopped = 1;
                        goto halt;
                  }

            /* stop scanning when we reach qtds the hc is using */
            } else if (likely (!stopped
                        && HC_IS_RUNNING (ehci_to_hcd(ehci)->state))) {
                  break;

            } else {
                  stopped = 1;

                  if (unlikely (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state)))
                        last_status = -ESHUTDOWN;

                  /* ignore active urbs unless some previous qtd
                   * for the urb faulted (including short read) or
                   * its urb was canceled.  we may patch qh or qtds.
                   */
                  if (likely(last_status == -EINPROGRESS &&
                              !urb->unlinked))
                        continue;

                  /* issue status after short control reads */
                  if (unlikely (do_status != 0)
                              && QTD_PID (token) == 0 /* OUT */) {
                        do_status = 0;
                        continue;
                  }

                  /* token in overlay may be most current */
                  if (state == QH_STATE_IDLE
                              && cpu_to_hc32(ehci, qtd->qtd_dma)
                                    == qh->hw_current)
                        token = hc32_to_cpu(ehci, qh->hw_token);

                  /* force halt for unlinked or blocked qh, so we'll
                   * patch the qh later and so that completions can't
                   * activate it while we "know" it's stopped.
                   */
                  if ((halt & qh->hw_token) == 0) {
halt:
                        qh->hw_token |= halt;
                        wmb ();
                  }
            }

            /* remove it from the queue */
            qtd_status = qtd_copy_status(ehci, urb, qtd->length, token);
            if (unlikely(qtd_status == -EREMOTEIO)) {
                  do_status = (!urb->unlinked &&
                              usb_pipecontrol(urb->pipe));
                  qtd_status = 0;
            }
            if (likely(last_status == -EINPROGRESS))
                  last_status = qtd_status;

            if (stopped && qtd->qtd_list.prev != &qh->qtd_list) {
                  last = list_entry (qtd->qtd_list.prev,
                              struct ehci_qtd, qtd_list);
                  last->hw_next = qtd->hw_next;
            }
            list_del (&qtd->qtd_list);
            last = qtd;
      }

      /* last urb's completion might still need calling */
      if (likely (last != NULL)) {
            ehci_urb_done(ehci, last->urb, last_status);
            count++;
            ehci_qtd_free (ehci, last);
      }

      /* restore original state; caller must unlink or relink */
      qh->qh_state = state;

      /* be sure the hardware's done with the qh before refreshing
       * it after fault cleanup, or recovering from silicon wrongly
       * overlaying the dummy qtd (which reduces DMA chatter).
       */
      if (stopped != 0 || qh->hw_qtd_next == EHCI_LIST_END(ehci)) {
            switch (state) {
            case QH_STATE_IDLE:
                  qh_refresh(ehci, qh);
                  break;
            case QH_STATE_LINKED:
                  /* should be rare for periodic transfers,
                   * except maybe high bandwidth ...
                   */
                  if ((cpu_to_hc32(ehci, QH_SMASK)
                              & qh->hw_info2) != 0) {
                        intr_deschedule (ehci, qh);
                        (void) qh_schedule (ehci, qh);
                  } else
                        unlink_async (ehci, qh);
                  break;
            /* otherwise, unlink already started */
            }
      }

      return count;
}

/*-------------------------------------------------------------------------*/

// high bandwidth multiplier, as encoded in highspeed endpoint descriptors
#define hb_mult(wMaxPacketSize) (1 + (((wMaxPacketSize) >> 11) & 0x03))
// ... and packet size, for any kind of endpoint descriptor
#define max_packet(wMaxPacketSize) ((wMaxPacketSize) & 0x07ff)

/*
 * reverse of qh_urb_transaction:  free a list of TDs.
 * used for cleanup after errors, before HC sees an URB's TDs.
 */
static void qtd_list_free (
      struct ehci_hcd         *ehci,
      struct urb        *urb,
      struct list_head  *qtd_list
) {
      struct list_head  *entry, *temp;

      list_for_each_safe (entry, temp, qtd_list) {
            struct ehci_qtd   *qtd;

            qtd = list_entry (entry, struct ehci_qtd, qtd_list);
            list_del (&qtd->qtd_list);
            ehci_qtd_free (ehci, qtd);
      }
}

/*
 * create a list of filled qtds for this URB; won't link into qh.
 */
static struct list_head *
qh_urb_transaction (
      struct ehci_hcd         *ehci,
      struct urb        *urb,
      struct list_head  *head,
      gfp_t             flags
) {
      struct ehci_qtd         *qtd, *qtd_prev;
      dma_addr_t        buf;
      int               len, maxpacket;
      int               is_input;
      u32               token;

      /*
       * URBs map to sequences of QTDs:  one logical transaction
       */
      qtd = ehci_qtd_alloc (ehci, flags);
      if (unlikely (!qtd))
            return NULL;
      list_add_tail (&qtd->qtd_list, head);
      qtd->urb = urb;

      token = QTD_STS_ACTIVE;
      token |= (EHCI_TUNE_CERR << 10);
      /* for split transactions, SplitXState initialized to zero */

      len = urb->transfer_buffer_length;
      is_input = usb_pipein (urb->pipe);
      if (usb_pipecontrol (urb->pipe)) {
            /* SETUP pid */
            qtd_fill(ehci, qtd, urb->setup_dma,
                        sizeof (struct usb_ctrlrequest),
                        token | (2 /* "setup" */ << 8), 8);

            /* ... and always at least one more pid */
            token ^= QTD_TOGGLE;
            qtd_prev = qtd;
            qtd = ehci_qtd_alloc (ehci, flags);
            if (unlikely (!qtd))
                  goto cleanup;
            qtd->urb = urb;
            qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
            list_add_tail (&qtd->qtd_list, head);

            /* for zero length DATA stages, STATUS is always IN */
            if (len == 0)
                  token |= (1 /* "in" */ << 8);
      }

      /*
       * data transfer stage:  buffer setup
       */
      buf = urb->transfer_dma;

      if (is_input)
            token |= (1 /* "in" */ << 8);
      /* else it's already initted to "out" pid (0 << 8) */

      maxpacket = max_packet(usb_maxpacket(urb->dev, urb->pipe, !is_input));

      /*
       * buffer gets wrapped in one or more qtds;
       * last one may be "short" (including zero len)
       * and may serve as a control status ack
       */
      for (;;) {
            int this_qtd_len;

            this_qtd_len = qtd_fill(ehci, qtd, buf, len, token, maxpacket);
            len -= this_qtd_len;
            buf += this_qtd_len;
            if (is_input)
                  qtd->hw_alt_next = ehci->async->hw_alt_next;

            /* qh makes control packets use qtd toggle; maybe switch it */
            if ((maxpacket & (this_qtd_len + (maxpacket - 1))) == 0)
                  token ^= QTD_TOGGLE;

            if (likely (len <= 0))
                  break;

            qtd_prev = qtd;
            qtd = ehci_qtd_alloc (ehci, flags);
            if (unlikely (!qtd))
                  goto cleanup;
            qtd->urb = urb;
            qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
            list_add_tail (&qtd->qtd_list, head);
      }

      /* unless the bulk/interrupt caller wants a chance to clean
       * up after short reads, hc should advance qh past this urb
       */
      if (likely ((urb->transfer_flags & URB_SHORT_NOT_OK) == 0
                        || usb_pipecontrol (urb->pipe)))
            qtd->hw_alt_next = EHCI_LIST_END(ehci);

      /*
       * control requests may need a terminating data "status" ack;
       * bulk ones may need a terminating short packet (zero length).
       */
      if (likely (urb->transfer_buffer_length != 0)) {
            int   one_more = 0;

            if (usb_pipecontrol (urb->pipe)) {
                  one_more = 1;
                  token ^= 0x0100;  /* "in" <--> "out"  */
                  token |= QTD_TOGGLE;    /* force DATA1 */
            } else if (usb_pipebulk (urb->pipe)
                        && (urb->transfer_flags & URB_ZERO_PACKET)
                        && !(urb->transfer_buffer_length % maxpacket)) {
                  one_more = 1;
            }
            if (one_more) {
                  qtd_prev = qtd;
                  qtd = ehci_qtd_alloc (ehci, flags);
                  if (unlikely (!qtd))
                        goto cleanup;
                  qtd->urb = urb;
                  qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
                  list_add_tail (&qtd->qtd_list, head);

                  /* never any data in such packets */
                  qtd_fill(ehci, qtd, 0, 0, token, 0);
            }
      }

      /* by default, enable interrupt on urb completion */
      if (likely (!(urb->transfer_flags & URB_NO_INTERRUPT)))
            qtd->hw_token |= cpu_to_hc32(ehci, QTD_IOC);
      return head;

cleanup:
      qtd_list_free (ehci, urb, head);
      return NULL;
}

/*-------------------------------------------------------------------------*/

// Would be best to create all qh's from config descriptors,
// when each interface/altsetting is established.  Unlink
// any previous qh and cancel its urbs first; endpoints are
// implicitly reset then (data toggle too).
// That'd mean updating how usbcore talks to HCDs. (2.7?)


/*
 * Each QH holds a qtd list; a QH is used for everything except iso.
 *
 * For interrupt urbs, the scheduler must set the microframe scheduling
 * mask(s) each time the QH gets scheduled.  For highspeed, that's
 * just one microframe in the s-mask.  For split interrupt transactions
 * there are additional complications: c-mask, maybe FSTNs.
 */
static struct ehci_qh *
qh_make (
      struct ehci_hcd         *ehci,
      struct urb        *urb,
      gfp_t             flags
) {
      struct ehci_qh          *qh = ehci_qh_alloc (ehci, flags);
      u32               info1 = 0, info2 = 0;
      int               is_input, type;
      int               maxp = 0;

      if (!qh)
            return qh;

      /*
       * init endpoint/device data for this QH
       */
      info1 |= usb_pipeendpoint (urb->pipe) << 8;
      info1 |= usb_pipedevice (urb->pipe) << 0;

      is_input = usb_pipein (urb->pipe);
      type = usb_pipetype (urb->pipe);
      maxp = usb_maxpacket (urb->dev, urb->pipe, !is_input);

      /* Compute interrupt scheduling parameters just once, and save.
       * - allowing for high bandwidth, how many nsec/uframe are used?
       * - split transactions need a second CSPLIT uframe; same question
       * - splits also need a schedule gap (for full/low speed I/O)
       * - qh has a polling interval
       *
       * For control/bulk requests, the HC or TT handles these.
       */
      if (type == PIPE_INTERRUPT) {
            qh->usecs = NS_TO_US (usb_calc_bus_time (USB_SPEED_HIGH, is_input, 0,
                        hb_mult (maxp) * max_packet (maxp)));
            qh->start = NO_FRAME;

            if (urb->dev->speed == USB_SPEED_HIGH) {
                  qh->c_usecs = 0;
                  qh->gap_uf = 0;

                  qh->period = urb->interval >> 3;
                  if (qh->period == 0 && urb->interval != 1) {
                        /* NOTE interval 2 or 4 uframes could work.
                         * But interval 1 scheduling is simpler, and
                         * includes high bandwidth.
                         */
                        dbg ("intr period %d uframes, NYET!",
                                    urb->interval);
                        goto done;
                  }
            } else {
                  struct usb_tt     *tt = urb->dev->tt;
                  int         think_time;

                  /* gap is f(FS/LS transfer times) */
                  qh->gap_uf = 1 + usb_calc_bus_time (urb->dev->speed,
                              is_input, 0, maxp) / (125 * 1000);

                  /* FIXME this just approximates SPLIT/CSPLIT times */
                  if (is_input) {         // SPLIT, gap, CSPLIT+DATA
                        qh->c_usecs = qh->usecs + HS_USECS (0);
                        qh->usecs = HS_USECS (1);
                  } else {          // SPLIT+DATA, gap, CSPLIT
                        qh->usecs += HS_USECS (1);
                        qh->c_usecs = HS_USECS (0);
                  }

                  think_time = tt ? tt->think_time : 0;
                  qh->tt_usecs = NS_TO_US (think_time +
                              usb_calc_bus_time (urb->dev->speed,
                              is_input, 0, max_packet (maxp)));
                  qh->period = urb->interval;
            }
      }

      /* support for tt scheduling, and access to toggles */
      qh->dev = urb->dev;

      /* using TT? */
      switch (urb->dev->speed) {
      case USB_SPEED_LOW:
            info1 |= (1 << 12);     /* EPS "low" */
            /* FALL THROUGH */

      case USB_SPEED_FULL:
            /* EPS 0 means "full" */
            if (type != PIPE_INTERRUPT)
                  info1 |= (EHCI_TUNE_RL_TT << 28);
            if (type == PIPE_CONTROL) {
                  info1 |= (1 << 27);     /* for TT */
                  info1 |= 1 << 14; /* toggle from qtd */
            }
            info1 |= maxp << 16;

            info2 |= (EHCI_TUNE_MULT_TT << 30);

            /* Some Freescale processors have an erratum in which the
             * port number in the queue head was 0..N-1 instead of 1..N.
             */
            if (ehci_has_fsl_portno_bug(ehci))
                  info2 |= (urb->dev->ttport-1) << 23;
            else
                  info2 |= urb->dev->ttport << 23;

            /* set the address of the TT; for TDI's integrated
             * root hub tt, leave it zeroed.
             */
            if (!ehci_is_TDI(ehci)
                        || urb->dev->tt->hub !=
                              ehci_to_hcd(ehci)->self.root_hub)
                  info2 |= urb->dev->tt->hub->devnum << 16;

            /* NOTE:  if (PIPE_INTERRUPT) { scheduler sets c-mask } */

            break;

      case USB_SPEED_HIGH:          /* no TT involved */
            info1 |= (2 << 12);     /* EPS "high" */
            if (type == PIPE_CONTROL) {
                  info1 |= (EHCI_TUNE_RL_HS << 28);
                  info1 |= 64 << 16;      /* usb2 fixed maxpacket */
                  info1 |= 1 << 14; /* toggle from qtd */
                  info2 |= (EHCI_TUNE_MULT_HS << 30);
            } else if (type == PIPE_BULK) {
                  info1 |= (EHCI_TUNE_RL_HS << 28);
                  info1 |= 512 << 16;     /* usb2 fixed maxpacket */
                  info2 |= (EHCI_TUNE_MULT_HS << 30);
            } else {          /* PIPE_INTERRUPT */
                  info1 |= max_packet (maxp) << 16;
                  info2 |= hb_mult (maxp) << 30;
            }
            break;
      default:
            dbg ("bogus dev %p speed %d", urb->dev, urb->dev->speed);
done:
            qh_put (qh);
            return NULL;
      }

      /* NOTE:  if (PIPE_INTERRUPT) { scheduler sets s-mask } */

      /* init as live, toggle clear, advance to dummy */
      qh->qh_state = QH_STATE_IDLE;
      qh->hw_info1 = cpu_to_hc32(ehci, info1);
      qh->hw_info2 = cpu_to_hc32(ehci, info2);
      usb_settoggle (urb->dev, usb_pipeendpoint (urb->pipe), !is_input, 1);
      qh_refresh (ehci, qh);
      return qh;
}

/*-------------------------------------------------------------------------*/

/* move qh (and its qtds) onto async queue; maybe enable queue.  */

static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
{
      __hc32            dma = QH_NEXT(ehci, qh->qh_dma);
      struct ehci_qh    *head;

      /* (re)start the async schedule? */
      head = ehci->async;
      timer_action_done (ehci, TIMER_ASYNC_OFF);
      if (!head->qh_next.qh) {
            u32   cmd = ehci_readl(ehci, &ehci->regs->command);

            if (!(cmd & CMD_ASE)) {
                  /* in case a clear of CMD_ASE didn't take yet */
                  (void)handshake(ehci, &ehci->regs->status,
                              STS_ASS, 0, 150);
                  cmd |= CMD_ASE | CMD_RUN;
                  ehci_writel(ehci, cmd, &ehci->regs->command);
                  ehci_to_hcd(ehci)->state = HC_STATE_RUNNING;
                  /* posted write need not be known to HC yet ... */
            }
      }

      /* clear halt and/or toggle; and maybe recover from silicon quirk */
      if (qh->qh_state == QH_STATE_IDLE)
            qh_refresh (ehci, qh);

      /* splice right after start */
      qh->qh_next = head->qh_next;
      qh->hw_next = head->hw_next;
      wmb ();

      head->qh_next.qh = qh;
      head->hw_next = dma;

      qh->qh_state = QH_STATE_LINKED;
      /* qtd completions reported later by interrupt */
}

/*-------------------------------------------------------------------------*/

/*
 * For control/bulk/interrupt, return QH with these TDs appended.
 * Allocates and initializes the QH if necessary.
 * Returns null if it can't allocate a QH it needs to.
 * If the QH has TDs (urbs) already, that's great.
 */
static struct ehci_qh *qh_append_tds (
      struct ehci_hcd         *ehci,
      struct urb        *urb,
      struct list_head  *qtd_list,
      int               epnum,
      void              **ptr
)
{
      struct ehci_qh          *qh = NULL;
      u32               qh_addr_mask = cpu_to_hc32(ehci, 0x7f);

      qh = (struct ehci_qh *) *ptr;
      if (unlikely (qh == NULL)) {
            /* can't sleep here, we have ehci->lock... */
            qh = qh_make (ehci, urb, GFP_ATOMIC);
            *ptr = qh;
      }
      if (likely (qh != NULL)) {
            struct ehci_qtd   *qtd;

            if (unlikely (list_empty (qtd_list)))
                  qtd = NULL;
            else
                  qtd = list_entry (qtd_list->next, struct ehci_qtd,
                              qtd_list);

            /* control qh may need patching ... */
            if (unlikely (epnum == 0)) {

                        /* usb_reset_device() briefly reverts to address 0 */
                        if (usb_pipedevice (urb->pipe) == 0)
                                qh->hw_info1 &= ~qh_addr_mask;
            }

            /* just one way to queue requests: swap with the dummy qtd.
             * only hc or qh_refresh() ever modify the overlay.
             */
            if (likely (qtd != NULL)) {
                  struct ehci_qtd         *dummy;
                  dma_addr_t        dma;
                  __hc32                  token;

                  /* to avoid racing the HC, use the dummy td instead of
                   * the first td of our list (becomes new dummy).  both
                   * tds stay deactivated until we're done, when the
                   * HC is allowed to fetch the old dummy (4.10.2).
                   */
                  token = qtd->hw_token;
                  qtd->hw_token = HALT_BIT(ehci);
                  wmb ();
                  dummy = qh->dummy;

                  dma = dummy->qtd_dma;
                  *dummy = *qtd;
                  dummy->qtd_dma = dma;

                  list_del (&qtd->qtd_list);
                  list_add (&dummy->qtd_list, qtd_list);
                  __list_splice (qtd_list, qh->qtd_list.prev);

                  ehci_qtd_init(ehci, qtd, qtd->qtd_dma);
                  qh->dummy = qtd;

                  /* hc must see the new dummy at list end */
                  dma = qtd->qtd_dma;
                  qtd = list_entry (qh->qtd_list.prev,
                              struct ehci_qtd, qtd_list);
                  qtd->hw_next = QTD_NEXT(ehci, dma);

                  /* let the hc process these next qtds */
                  wmb ();
                  dummy->hw_token = token;

                  urb->hcpriv = qh_get (qh);
            }
      }
      return qh;
}

/*-------------------------------------------------------------------------*/

static int
submit_async (
      struct ehci_hcd         *ehci,
      struct urb        *urb,
      struct list_head  *qtd_list,
      gfp_t             mem_flags
) {
      struct ehci_qtd         *qtd;
      int               epnum;
      unsigned long           flags;
      struct ehci_qh          *qh = NULL;
      int               rc;

      qtd = list_entry (qtd_list->next, struct ehci_qtd, qtd_list);
      epnum = urb->ep->desc.bEndpointAddress;

#ifdef EHCI_URB_TRACE
      ehci_dbg (ehci,
            "%s %s urb %p ep%d%s len %d, qtd %p [qh %p]\n",
            __FUNCTION__, urb->dev->devpath, urb,
            epnum & 0x0f, (epnum & USB_DIR_IN) ? "in" : "out",
            urb->transfer_buffer_length,
            qtd, urb->ep->hcpriv);
#endif

      spin_lock_irqsave (&ehci->lock, flags);
      if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
                         &ehci_to_hcd(ehci)->flags))) {
            rc = -ESHUTDOWN;
            goto done;
      }
      rc = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
      if (unlikely(rc))
            goto done;

      qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
      if (unlikely(qh == NULL)) {
            usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
            rc = -ENOMEM;
            goto done;
      }

      /* Control/bulk operations through TTs don't need scheduling,
       * the HC and TT handle it when the TT has a buffer ready.
       */
      if (likely (qh->qh_state == QH_STATE_IDLE))
            qh_link_async (ehci, qh_get (qh));
 done:
      spin_unlock_irqrestore (&ehci->lock, flags);
      if (unlikely (qh == NULL))
            qtd_list_free (ehci, urb, qtd_list);
      return rc;
}

/*-------------------------------------------------------------------------*/

/* the async qh for the qtds being reclaimed are now unlinked from the HC */

static void end_unlink_async (struct ehci_hcd *ehci)
{
      struct ehci_qh          *qh = ehci->reclaim;
      struct ehci_qh          *next;

      timer_action_done (ehci, TIMER_IAA_WATCHDOG);

      // qh->hw_next = cpu_to_hc32(qh->qh_dma);
      qh->qh_state = QH_STATE_IDLE;
      qh->qh_next.qh = NULL;
      qh_put (qh);                  // refcount from reclaim

      /* other unlink(s) may be pending (in QH_STATE_UNLINK_WAIT) */
      next = qh->reclaim;
      ehci->reclaim = next;
      ehci->reclaim_ready = 0;
      qh->reclaim = NULL;

      qh_completions (ehci, qh);

      if (!list_empty (&qh->qtd_list)
                  && HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
            qh_link_async (ehci, qh);
      else {
            qh_put (qh);            // refcount from async list

            /* it's not free to turn the async schedule on/off; leave it
             * active but idle for a while once it empties.
             */
            if (HC_IS_RUNNING (ehci_to_hcd(ehci)->state)
                        && ehci->async->qh_next.qh == NULL)
                  timer_action (ehci, TIMER_ASYNC_OFF);
      }

      if (next) {
            ehci->reclaim = NULL;
            start_unlink_async (ehci, next);
      }
}

/* makes sure the async qh will become idle */
/* caller must own ehci->lock */

static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
{
      int         cmd = ehci_readl(ehci, &ehci->regs->command);
      struct ehci_qh    *prev;

#ifdef DEBUG
      assert_spin_locked(&ehci->lock);
      if (ehci->reclaim
                  || (qh->qh_state != QH_STATE_LINKED
                        && qh->qh_state != QH_STATE_UNLINK_WAIT)
                  )
            BUG ();
#endif

      /* stop async schedule right now? */
      if (unlikely (qh == ehci->async)) {
            /* can't get here without STS_ASS set */
            if (ehci_to_hcd(ehci)->state != HC_STATE_HALT
                        && !ehci->reclaim) {
                  /* ... and CMD_IAAD clear */
                  ehci_writel(ehci, cmd & ~CMD_ASE,
                            &ehci->regs->command);
                  wmb ();
                  // handshake later, if we need to
                  timer_action_done (ehci, TIMER_ASYNC_OFF);
            }
            return;
      }

      qh->qh_state = QH_STATE_UNLINK;
      ehci->reclaim = qh = qh_get (qh);

      prev = ehci->async;
      while (prev->qh_next.qh != qh)
            prev = prev->qh_next.qh;

      prev->hw_next = qh->hw_next;
      prev->qh_next = qh->qh_next;
      wmb ();

      if (unlikely (ehci_to_hcd(ehci)->state == HC_STATE_HALT)) {
            /* if (unlikely (qh->reclaim != 0))
             *    this will recurse, probably not much
             */
            end_unlink_async (ehci);
            return;
      }

      ehci->reclaim_ready = 0;
      cmd |= CMD_IAAD;
      ehci_writel(ehci, cmd, &ehci->regs->command);
      (void)ehci_readl(ehci, &ehci->regs->command);
      timer_action (ehci, TIMER_IAA_WATCHDOG);
}

/*-------------------------------------------------------------------------*/

static void scan_async (struct ehci_hcd *ehci)
{
      struct ehci_qh          *qh;
      enum ehci_timer_action  action = TIMER_IO_WATCHDOG;

      if (!++(ehci->stamp))
            ehci->stamp++;
      timer_action_done (ehci, TIMER_ASYNC_SHRINK);
rescan:
      qh = ehci->async->qh_next.qh;
      if (likely (qh != NULL)) {
            do {
                  /* clean any finished work for this qh */
                  if (!list_empty (&qh->qtd_list)
                              && qh->stamp != ehci->stamp) {
                        int temp;

                        /* unlinks could happen here; completion
                         * reporting drops the lock.  rescan using
                         * the latest schedule, but don't rescan
                         * qhs we already finished (no looping).
                         */
                        qh = qh_get (qh);
                        qh->stamp = ehci->stamp;
                        temp = qh_completions (ehci, qh);
                        qh_put (qh);
                        if (temp != 0) {
                              goto rescan;
                        }
                  }

                  /* unlink idle entries, reducing HC PCI usage as well
                   * as HCD schedule-scanning costs.  delay for any qh
                   * we just scanned, there's a not-unusual case that it
                   * doesn't stay idle for long.
                   * (plus, avoids some kind of re-activation race.)
                   */
                  if (list_empty (&qh->qtd_list)) {
                        if (qh->stamp == ehci->stamp)
                              action = TIMER_ASYNC_SHRINK;
                        else if (!ehci->reclaim
                                  && qh->qh_state == QH_STATE_LINKED)
                              start_unlink_async (ehci, qh);
                  }

                  qh = qh->qh_next.qh;
            } while (qh);
      }
      if (action == TIMER_ASYNC_SHRINK)
            timer_action (ehci, TIMER_ASYNC_SHRINK);
}

Generated by  Doxygen 1.6.0   Back to index