diff options
Diffstat (limited to 'drivers/usb/host/ehci-sched.c')
| -rw-r--r-- | drivers/usb/host/ehci-sched.c | 71 |
1 files changed, 46 insertions, 25 deletions
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c index 69b1861e4325..eec8446f8ded 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -578,12 +578,20 @@ static void qh_unlink_periodic(struct ehci_hcd *ehci, struct ehci_qh *qh) unsigned i; unsigned period; - // FIXME: - // IF this isn't high speed - // and this qh is active in the current uframe - // (and overlay token SplitXstate is false?) - // THEN - // qh->hw_info1 |= cpu_to_hc32(1 << 7 /* "ignore" */); + /* + * If qh is for a low/full-speed device, simply unlinking it + * could interfere with an ongoing split transaction. To unlink + * it safely would require setting the QH_INACTIVATE bit and + * waiting at least one frame, as described in EHCI 4.12.2.5. + * + * We won't bother with any of this. Instead, we assume that the + * only reason for unlinking an interrupt QH while the current URB + * is still active is to dequeue all the URBs (flush the whole + * endpoint queue). + * + * If rebalancing the periodic schedule is ever implemented, this + * approach will no longer be valid. + */ /* high bandwidth, or otherwise part of every microframe */ if ((period = qh->period) == 0) @@ -608,12 +616,8 @@ static void qh_unlink_periodic(struct ehci_hcd *ehci, struct ehci_qh *qh) qh->qh_next.ptr = NULL; } -static void intr_deschedule (struct ehci_hcd *ehci, struct ehci_qh *qh) +static void start_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh) { - unsigned wait; - struct ehci_qh_hw *hw = qh->hw; - int rc; - /* If the QH isn't linked then there's nothing we can do * unless we were called during a giveback, in which case * qh_completions() has to deal with it. @@ -626,28 +630,45 @@ static void intr_deschedule (struct ehci_hcd *ehci, struct ehci_qh *qh) qh_unlink_periodic (ehci, qh); - /* simple/paranoid: always delay, expecting the HC needs to read - * qh->hw_next or finish a writeback after SPLIT/CSPLIT ... and - * expect khubd to clean up after any CSPLITs we won't issue. - * active high speed queues may need bigger delays... + /* Make sure the unlinks are visible before starting the timer */ + wmb(); + + /* + * The EHCI spec doesn't say how long it takes the controller to + * stop accessing an unlinked interrupt QH. The timer delay is + * 9 uframes; presumably that will be long enough. */ - if (list_empty (&qh->qtd_list) - || (cpu_to_hc32(ehci, QH_CMASK) - & hw->hw_info2) != 0) - wait = 2; + qh->unlink_cycle = ehci->intr_unlink_cycle; + + /* New entries go at the end of the intr_unlink list */ + if (ehci->intr_unlink) + ehci->intr_unlink_last->unlink_next = qh; else - wait = 55; /* worst case: 3 * 1024 */ + ehci->intr_unlink = qh; + ehci->intr_unlink_last = qh; + + if (ehci->intr_unlinking) + ; /* Avoid recursive calls */ + else if (ehci->rh_state < EHCI_RH_RUNNING) + ehci_handle_intr_unlinks(ehci); + else if (ehci->intr_unlink == qh) { + ehci_enable_event(ehci, EHCI_HRTIMER_UNLINK_INTR, true); + ++ehci->intr_unlink_cycle; + } +} + +static void end_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh) +{ + struct ehci_qh_hw *hw = qh->hw; + int rc; - udelay (wait); qh->qh_state = QH_STATE_IDLE; hw->hw_next = EHCI_LIST_END(ehci); - wmb (); qh_completions(ehci, qh); /* reschedule QH iff another request is queued */ - if (!list_empty(&qh->qtd_list) && - ehci->rh_state == EHCI_RH_RUNNING) { + if (!list_empty(&qh->qtd_list) && ehci->rh_state == EHCI_RH_RUNNING) { rc = qh_schedule(ehci, qh); /* An error here likely indicates handshake failure @@ -2302,7 +2323,7 @@ restart: temp.qh->stamp = ehci->periodic_stamp; if (unlikely(list_empty(&temp.qh->qtd_list) || temp.qh->needs_rescan)) - intr_deschedule(ehci, temp.qh); + start_unlink_intr(ehci, temp.qh); } break; case Q_TYPE_FSTN: |