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linux_dsm_epyc7002/drivers/usb/host/ehci-sched.c
Alan Stern 55934eb3b9 USB: EHCI: use hrtimer for (s)iTD deallocation 
This patch (as1579) adds an hrtimer event to handle deallocation of
iTDs and siTDs in ehci-hcd.

Because of the frame-oriented approach used by the EHCI periodic
schedule, the hardware can continue to access the Transfer Descriptor
for isochronous (or split-isochronous) transactions for up to a
millisecond after the transaction completes.  The iTD (or siTD) must
not be reused before then.

The strategy currently used involves putting completed iTDs on a list
of cached entries and every so often returning them to the endpoint's
free list.  The new strategy reduces overhead by putting completed
iTDs back on the free list immediately, although they are not reused
until it is safe to do so.

When the isochronous endpoint stops (its queue becomes empty), the
iTDs on its free list get moved to a global list, from which they will
be deallocated after a minimum of 2 ms.  This delay is what the new
hrtimer event is for.

Overall this may not be a tremendous improvement over the current
code, but to me it seems a lot more clear and logical.  In addition,
it removes the need for each iTD to keep a reference to the
ehci_iso_stream it belongs to, since the iTD never needs to be moved
back to the stream's free list from the global list.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-16 16:54:25 -07:00

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/*
* Copyright (c) 2001-2004 by David Brownell
* Copyright (c) 2003 Michal Sojka, for high-speed iso transfers
*
* 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 scheduled transaction support: interrupt, iso, split iso
* These are called "periodic" transactions in the EHCI spec.
*
* Note that for interrupt transfers, the QH/QTD manipulation is shared
* with the "asynchronous" transaction support (control/bulk transfers).
* The only real difference is in how interrupt transfers are scheduled.
*
* For ISO, we make an "iso_stream" head to serve the same role as a QH.
* It keeps track of every ITD (or SITD) that's linked, and holds enough
* pre-calculated schedule data to make appending to the queue be quick.
*/
static int ehci_get_frame (struct usb_hcd *hcd);
#ifdef CONFIG_PCI
static unsigned ehci_read_frame_index(struct ehci_hcd *ehci)
{
unsigned uf;
/*
* The MosChip MCS9990 controller updates its microframe counter
* a little before the frame counter, and occasionally we will read
* the invalid intermediate value. Avoid problems by checking the
* microframe number (the low-order 3 bits); if they are 0 then
* re-read the register to get the correct value.
*/
uf = ehci_readl(ehci, &ehci->regs->frame_index);
if (unlikely(ehci->frame_index_bug && ((uf & 7) == 0)))
uf = ehci_readl(ehci, &ehci->regs->frame_index);
return uf;
}
#endif
/*-------------------------------------------------------------------------*/
/*
* periodic_next_shadow - return "next" pointer on shadow list
* @periodic: host pointer to qh/itd/sitd
* @tag: hardware tag for type of this record
*/
static union ehci_shadow *
periodic_next_shadow(struct ehci_hcd *ehci, union ehci_shadow *periodic,
__hc32 tag)
{
switch (hc32_to_cpu(ehci, tag)) {
case Q_TYPE_QH:
return &periodic->qh->qh_next;
case Q_TYPE_FSTN:
return &periodic->fstn->fstn_next;
case Q_TYPE_ITD:
return &periodic->itd->itd_next;
// case Q_TYPE_SITD:
default:
return &periodic->sitd->sitd_next;
}
}
static __hc32 *
shadow_next_periodic(struct ehci_hcd *ehci, union ehci_shadow *periodic,
__hc32 tag)
{
switch (hc32_to_cpu(ehci, tag)) {
/* our ehci_shadow.qh is actually software part */
case Q_TYPE_QH:
return &periodic->qh->hw->hw_next;
/* others are hw parts */
default:
return periodic->hw_next;
}
}
/* caller must hold ehci->lock */
static void periodic_unlink (struct ehci_hcd *ehci, unsigned frame, void *ptr)
{
union ehci_shadow *prev_p = &ehci->pshadow[frame];
__hc32 *hw_p = &ehci->periodic[frame];
union ehci_shadow here = *prev_p;
/* find predecessor of "ptr"; hw and shadow lists are in sync */
while (here.ptr && here.ptr != ptr) {
prev_p = periodic_next_shadow(ehci, prev_p,
Q_NEXT_TYPE(ehci, *hw_p));
hw_p = shadow_next_periodic(ehci, &here,
Q_NEXT_TYPE(ehci, *hw_p));
here = *prev_p;
}
/* an interrupt entry (at list end) could have been shared */
if (!here.ptr)
return;
/* update shadow and hardware lists ... the old "next" pointers
* from ptr may still be in use, the caller updates them.
*/
*prev_p = *periodic_next_shadow(ehci, &here,
Q_NEXT_TYPE(ehci, *hw_p));
if (!ehci->use_dummy_qh ||
*shadow_next_periodic(ehci, &here, Q_NEXT_TYPE(ehci, *hw_p))
!= EHCI_LIST_END(ehci))
*hw_p = *shadow_next_periodic(ehci, &here,
Q_NEXT_TYPE(ehci, *hw_p));
else
*hw_p = ehci->dummy->qh_dma;
}
/* how many of the uframe's 125 usecs are allocated? */
static unsigned short
periodic_usecs (struct ehci_hcd *ehci, unsigned frame, unsigned uframe)
{
__hc32 *hw_p = &ehci->periodic [frame];
union ehci_shadow *q = &ehci->pshadow [frame];
unsigned usecs = 0;
struct ehci_qh_hw *hw;
while (q->ptr) {
switch (hc32_to_cpu(ehci, Q_NEXT_TYPE(ehci, *hw_p))) {
case Q_TYPE_QH:
hw = q->qh->hw;
/* is it in the S-mask? */
if (hw->hw_info2 & cpu_to_hc32(ehci, 1 << uframe))
usecs += q->qh->usecs;
/* ... or C-mask? */
if (hw->hw_info2 & cpu_to_hc32(ehci,
1 << (8 + uframe)))
usecs += q->qh->c_usecs;
hw_p = &hw->hw_next;
q = &q->qh->qh_next;
break;
// case Q_TYPE_FSTN:
default:
/* for "save place" FSTNs, count the relevant INTR
* bandwidth from the previous frame
*/
if (q->fstn->hw_prev != EHCI_LIST_END(ehci)) {
ehci_dbg (ehci, "ignoring FSTN cost ...\n");
}
hw_p = &q->fstn->hw_next;
q = &q->fstn->fstn_next;
break;
case Q_TYPE_ITD:
if (q->itd->hw_transaction[uframe])
usecs += q->itd->stream->usecs;
hw_p = &q->itd->hw_next;
q = &q->itd->itd_next;
break;
case Q_TYPE_SITD:
/* is it in the S-mask? (count SPLIT, DATA) */
if (q->sitd->hw_uframe & cpu_to_hc32(ehci,
1 << uframe)) {
if (q->sitd->hw_fullspeed_ep &
cpu_to_hc32(ehci, 1<<31))
usecs += q->sitd->stream->usecs;
else /* worst case for OUT start-split */
usecs += HS_USECS_ISO (188);
}
/* ... C-mask? (count CSPLIT, DATA) */
if (q->sitd->hw_uframe &
cpu_to_hc32(ehci, 1 << (8 + uframe))) {
/* worst case for IN complete-split */
usecs += q->sitd->stream->c_usecs;
}
hw_p = &q->sitd->hw_next;
q = &q->sitd->sitd_next;
break;
}
}
#ifdef DEBUG
if (usecs > ehci->uframe_periodic_max)
ehci_err (ehci, "uframe %d sched overrun: %d usecs\n",
frame * 8 + uframe, usecs);
#endif
return usecs;
}
/*-------------------------------------------------------------------------*/
static int same_tt (struct usb_device *dev1, struct usb_device *dev2)
{
if (!dev1->tt || !dev2->tt)
return 0;
if (dev1->tt != dev2->tt)
return 0;
if (dev1->tt->multi)
return dev1->ttport == dev2->ttport;
else
return 1;
}
#ifdef CONFIG_USB_EHCI_TT_NEWSCHED
/* Which uframe does the low/fullspeed transfer start in?
*
* The parameter is the mask of ssplits in "H-frame" terms
* and this returns the transfer start uframe in "B-frame" terms,
* which allows both to match, e.g. a ssplit in "H-frame" uframe 0
* will cause a transfer in "B-frame" uframe 0. "B-frames" lag
* "H-frames" by 1 uframe. See the EHCI spec sec 4.5 and figure 4.7.
*/
static inline unsigned char tt_start_uframe(struct ehci_hcd *ehci, __hc32 mask)
{
unsigned char smask = QH_SMASK & hc32_to_cpu(ehci, mask);
if (!smask) {
ehci_err(ehci, "invalid empty smask!\n");
/* uframe 7 can't have bw so this will indicate failure */
return 7;
}
return ffs(smask) - 1;
}
static const unsigned char
max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 30, 0 };
/* carryover low/fullspeed bandwidth that crosses uframe boundries */
static inline void carryover_tt_bandwidth(unsigned short tt_usecs[8])
{
int i;
for (i=0; i<7; i++) {
if (max_tt_usecs[i] < tt_usecs[i]) {
tt_usecs[i+1] += tt_usecs[i] - max_tt_usecs[i];
tt_usecs[i] = max_tt_usecs[i];
}
}
}
/* How many of the tt's periodic downstream 1000 usecs are allocated?
*
* While this measures the bandwidth in terms of usecs/uframe,
* the low/fullspeed bus has no notion of uframes, so any particular
* low/fullspeed transfer can "carry over" from one uframe to the next,
* since the TT just performs downstream transfers in sequence.
*
* For example two separate 100 usec transfers can start in the same uframe,
* and the second one would "carry over" 75 usecs into the next uframe.
*/
static void
periodic_tt_usecs (
struct ehci_hcd *ehci,
struct usb_device *dev,
unsigned frame,
unsigned short tt_usecs[8]
)
{
__hc32 *hw_p = &ehci->periodic [frame];
union ehci_shadow *q = &ehci->pshadow [frame];
unsigned char uf;
memset(tt_usecs, 0, 16);
while (q->ptr) {
switch (hc32_to_cpu(ehci, Q_NEXT_TYPE(ehci, *hw_p))) {
case Q_TYPE_ITD:
hw_p = &q->itd->hw_next;
q = &q->itd->itd_next;
continue;
case Q_TYPE_QH:
if (same_tt(dev, q->qh->dev)) {
uf = tt_start_uframe(ehci, q->qh->hw->hw_info2);
tt_usecs[uf] += q->qh->tt_usecs;
}
hw_p = &q->qh->hw->hw_next;
q = &q->qh->qh_next;
continue;
case Q_TYPE_SITD:
if (same_tt(dev, q->sitd->urb->dev)) {
uf = tt_start_uframe(ehci, q->sitd->hw_uframe);
tt_usecs[uf] += q->sitd->stream->tt_usecs;
}
hw_p = &q->sitd->hw_next;
q = &q->sitd->sitd_next;
continue;
// case Q_TYPE_FSTN:
default:
ehci_dbg(ehci, "ignoring periodic frame %d FSTN\n",
frame);
hw_p = &q->fstn->hw_next;
q = &q->fstn->fstn_next;
}
}
carryover_tt_bandwidth(tt_usecs);
if (max_tt_usecs[7] < tt_usecs[7])
ehci_err(ehci, "frame %d tt sched overrun: %d usecs\n",
frame, tt_usecs[7] - max_tt_usecs[7]);
}
/*
* Return true if the device's tt's downstream bus is available for a
* periodic transfer of the specified length (usecs), starting at the
* specified frame/uframe. Note that (as summarized in section 11.19
* of the usb 2.0 spec) TTs can buffer multiple transactions for each
* uframe.
*
* The uframe parameter is when the fullspeed/lowspeed transfer
* should be executed in "B-frame" terms, which is the same as the
* highspeed ssplit's uframe (which is in "H-frame" terms). For example
* a ssplit in "H-frame" 0 causes a transfer in "B-frame" 0.
* See the EHCI spec sec 4.5 and fig 4.7.
*
* This checks if the full/lowspeed bus, at the specified starting uframe,
* has the specified bandwidth available, according to rules listed
* in USB 2.0 spec section 11.18.1 fig 11-60.
*
* This does not check if the transfer would exceed the max ssplit
* limit of 16, specified in USB 2.0 spec section 11.18.4 requirement #4,
* since proper scheduling limits ssplits to less than 16 per uframe.
*/
static int tt_available (
struct ehci_hcd *ehci,
unsigned period,
struct usb_device *dev,
unsigned frame,
unsigned uframe,
u16 usecs
)
{
if ((period == 0) || (uframe >= 7)) /* error */
return 0;
for (; frame < ehci->periodic_size; frame += period) {
unsigned short tt_usecs[8];
periodic_tt_usecs (ehci, dev, frame, tt_usecs);
ehci_vdbg(ehci, "tt frame %d check %d usecs start uframe %d in"
" schedule %d/%d/%d/%d/%d/%d/%d/%d\n",
frame, usecs, uframe,
tt_usecs[0], tt_usecs[1], tt_usecs[2], tt_usecs[3],
tt_usecs[4], tt_usecs[5], tt_usecs[6], tt_usecs[7]);
if (max_tt_usecs[uframe] <= tt_usecs[uframe]) {
ehci_vdbg(ehci, "frame %d uframe %d fully scheduled\n",
frame, uframe);
return 0;
}
/* special case for isoc transfers larger than 125us:
* the first and each subsequent fully used uframe
* must be empty, so as to not illegally delay
* already scheduled transactions
*/
if (125 < usecs) {
int ufs = (usecs / 125);
int i;
for (i = uframe; i < (uframe + ufs) && i < 8; i++)
if (0 < tt_usecs[i]) {
ehci_vdbg(ehci,
"multi-uframe xfer can't fit "
"in frame %d uframe %d\n",
frame, i);
return 0;
}
}
tt_usecs[uframe] += usecs;
carryover_tt_bandwidth(tt_usecs);
/* fail if the carryover pushed bw past the last uframe's limit */
if (max_tt_usecs[7] < tt_usecs[7]) {
ehci_vdbg(ehci,
"tt unavailable usecs %d frame %d uframe %d\n",
usecs, frame, uframe);
return 0;
}
}
return 1;
}
#else
/* return true iff the device's transaction translator is available
* for a periodic transfer starting at the specified frame, using
* all the uframes in the mask.
*/
static int tt_no_collision (
struct ehci_hcd *ehci,
unsigned period,
struct usb_device *dev,
unsigned frame,
u32 uf_mask
)
{
if (period == 0) /* error */
return 0;
/* note bandwidth wastage: split never follows csplit
* (different dev or endpoint) until the next uframe.
* calling convention doesn't make that distinction.
*/
for (; frame < ehci->periodic_size; frame += period) {
union ehci_shadow here;
__hc32 type;
struct ehci_qh_hw *hw;
here = ehci->pshadow [frame];
type = Q_NEXT_TYPE(ehci, ehci->periodic [frame]);
while (here.ptr) {
switch (hc32_to_cpu(ehci, type)) {
case Q_TYPE_ITD:
type = Q_NEXT_TYPE(ehci, here.itd->hw_next);
here = here.itd->itd_next;
continue;
case Q_TYPE_QH:
hw = here.qh->hw;
if (same_tt (dev, here.qh->dev)) {
u32 mask;
mask = hc32_to_cpu(ehci,
hw->hw_info2);
/* "knows" no gap is needed */
mask |= mask >> 8;
if (mask & uf_mask)
break;
}
type = Q_NEXT_TYPE(ehci, hw->hw_next);
here = here.qh->qh_next;
continue;
case Q_TYPE_SITD:
if (same_tt (dev, here.sitd->urb->dev)) {
u16 mask;
mask = hc32_to_cpu(ehci, here.sitd
->hw_uframe);
/* FIXME assumes no gap for IN! */
mask |= mask >> 8;
if (mask & uf_mask)
break;
}
type = Q_NEXT_TYPE(ehci, here.sitd->hw_next);
here = here.sitd->sitd_next;
continue;
// case Q_TYPE_FSTN:
default:
ehci_dbg (ehci,
"periodic frame %d bogus type %d\n",
frame, type);
}
/* collision or error */
return 0;
}
}
/* no collision */
return 1;
}
#endif /* CONFIG_USB_EHCI_TT_NEWSCHED */
/*-------------------------------------------------------------------------*/
static void enable_periodic(struct ehci_hcd *ehci)
{
if (ehci->periodic_count++)
return;
/* Stop waiting to turn off the periodic schedule */
ehci->enabled_hrtimer_events &= ~BIT(EHCI_HRTIMER_DISABLE_PERIODIC);
/* Don't start the schedule until PSS is 0 */
ehci_poll_PSS(ehci);
}
static void disable_periodic(struct ehci_hcd *ehci)
{
if (--ehci->periodic_count)
return;
ehci->next_uframe = -1; /* the periodic schedule is empty */
/* Don't turn off the schedule until PSS is 1 */
ehci_poll_PSS(ehci);
}
/*-------------------------------------------------------------------------*/
/* periodic schedule slots have iso tds (normal or split) first, then a
* sparse tree for active interrupt transfers.
*
* this just links in a qh; caller guarantees uframe masks are set right.
* no FSTN support (yet; ehci 0.96+)
*/
static void qh_link_periodic(struct ehci_hcd *ehci, struct ehci_qh *qh)
{
unsigned i;
unsigned period = qh->period;
dev_dbg (&qh->dev->dev,
"link qh%d-%04x/%p start %d [%d/%d us]\n",
period, hc32_to_cpup(ehci, &qh->hw->hw_info2)
& (QH_CMASK | QH_SMASK),
qh, qh->start, qh->usecs, qh->c_usecs);
/* high bandwidth, or otherwise every microframe */
if (period == 0)
period = 1;
for (i = qh->start; i < ehci->periodic_size; i += period) {
union ehci_shadow *prev = &ehci->pshadow[i];
__hc32 *hw_p = &ehci->periodic[i];
union ehci_shadow here = *prev;
__hc32 type = 0;
/* skip the iso nodes at list head */
while (here.ptr) {
type = Q_NEXT_TYPE(ehci, *hw_p);
if (type == cpu_to_hc32(ehci, Q_TYPE_QH))
break;
prev = periodic_next_shadow(ehci, prev, type);
hw_p = shadow_next_periodic(ehci, &here, type);
here = *prev;
}
/* sorting each branch by period (slow-->fast)
* enables sharing interior tree nodes
*/
while (here.ptr && qh != here.qh) {
if (qh->period > here.qh->period)
break;
prev = &here.qh->qh_next;
hw_p = &here.qh->hw->hw_next;
here = *prev;
}
/* link in this qh, unless some earlier pass did that */
if (qh != here.qh) {
qh->qh_next = here;
if (here.qh)
qh->hw->hw_next = *hw_p;
wmb ();
prev->qh = qh;
*hw_p = QH_NEXT (ehci, qh->qh_dma);
}
}
qh->qh_state = QH_STATE_LINKED;
qh->xacterrs = 0;
/* update per-qh bandwidth for usbfs */
ehci_to_hcd(ehci)->self.bandwidth_allocated += qh->period
? ((qh->usecs + qh->c_usecs) / qh->period)
: (qh->usecs * 8);
/* maybe enable periodic schedule processing */
enable_periodic(ehci);
}
static void qh_unlink_periodic(struct ehci_hcd *ehci, struct ehci_qh *qh)
{
unsigned i;
unsigned period;
/*
* 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)
period = 1;
for (i = qh->start; i < ehci->periodic_size; i += period)
periodic_unlink (ehci, i, qh);
/* update per-qh bandwidth for usbfs */
ehci_to_hcd(ehci)->self.bandwidth_allocated -= qh->period
? ((qh->usecs + qh->c_usecs) / qh->period)
: (qh->usecs * 8);
dev_dbg (&qh->dev->dev,
"unlink qh%d-%04x/%p start %d [%d/%d us]\n",
qh->period,
hc32_to_cpup(ehci, &qh->hw->hw_info2) & (QH_CMASK | QH_SMASK),
qh, qh->start, qh->usecs, qh->c_usecs);
/* qh->qh_next still "live" to HC */
qh->qh_state = QH_STATE_UNLINK;
qh->qh_next.ptr = NULL;
}
static void start_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh)
{
/* 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.
*/
if (qh->qh_state != QH_STATE_LINKED) {
if (qh->qh_state == QH_STATE_COMPLETING)
qh->needs_rescan = 1;
return;
}
qh_unlink_periodic (ehci, qh);
/* 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.
*/
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
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;
qh->qh_state = QH_STATE_IDLE;
hw->hw_next = EHCI_LIST_END(ehci);
qh_completions(ehci, qh);
/* reschedule QH iff another request is queued */
if (!list_empty(&qh->qtd_list) && ehci->rh_state == EHCI_RH_RUNNING) {
rc = qh_schedule(ehci, qh);
/* An error here likely indicates handshake failure
* or no space left in the schedule. Neither fault
* should happen often ...
*
* FIXME kill the now-dysfunctional queued urbs
*/
if (rc != 0)
ehci_err(ehci, "can't reschedule qh %p, err %d\n",
qh, rc);
}
/* maybe turn off periodic schedule */
disable_periodic(ehci);
}
/*-------------------------------------------------------------------------*/
static int check_period (
struct ehci_hcd *ehci,
unsigned frame,
unsigned uframe,
unsigned period,
unsigned usecs
) {
int claimed;
/* complete split running into next frame?
* given FSTN support, we could sometimes check...
*/
if (uframe >= 8)
return 0;
/* convert "usecs we need" to "max already claimed" */
usecs = ehci->uframe_periodic_max - usecs;
/* we "know" 2 and 4 uframe intervals were rejected; so
* for period 0, check _every_ microframe in the schedule.
*/
if (unlikely (period == 0)) {
do {
for (uframe = 0; uframe < 7; uframe++) {
claimed = periodic_usecs (ehci, frame, uframe);
if (claimed > usecs)
return 0;
}
} while ((frame += 1) < ehci->periodic_size);
/* just check the specified uframe, at that period */
} else {
do {
claimed = periodic_usecs (ehci, frame, uframe);
if (claimed > usecs)
return 0;
} while ((frame += period) < ehci->periodic_size);
}
// success!
return 1;
}
static int check_intr_schedule (
struct ehci_hcd *ehci,
unsigned frame,
unsigned uframe,
const struct ehci_qh *qh,
__hc32 *c_maskp
)
{
int retval = -ENOSPC;
u8 mask = 0;
if (qh->c_usecs && uframe >= 6) /* FSTN territory? */
goto done;
if (!check_period (ehci, frame, uframe, qh->period, qh->usecs))
goto done;
if (!qh->c_usecs) {
retval = 0;
*c_maskp = 0;
goto done;
}
#ifdef CONFIG_USB_EHCI_TT_NEWSCHED
if (tt_available (ehci, qh->period, qh->dev, frame, uframe,
qh->tt_usecs)) {
unsigned i;
/* TODO : this may need FSTN for SSPLIT in uframe 5. */
for (i=uframe+1; i<8 && i<uframe+4; i++)
if (!check_period (ehci, frame, i,
qh->period, qh->c_usecs))
goto done;
else
mask |= 1 << i;
retval = 0;
*c_maskp = cpu_to_hc32(ehci, mask << 8);
}
#else
/* Make sure this tt's buffer is also available for CSPLITs.
* We pessimize a bit; probably the typical full speed case
* doesn't need the second CSPLIT.
*
* NOTE: both SPLIT and CSPLIT could be checked in just
* one smart pass...
*/
mask = 0x03 << (uframe + qh->gap_uf);
*c_maskp = cpu_to_hc32(ehci, mask << 8);
mask |= 1 << uframe;
if (tt_no_collision (ehci, qh->period, qh->dev, frame, mask)) {
if (!check_period (ehci, frame, uframe + qh->gap_uf + 1,
qh->period, qh->c_usecs))
goto done;
if (!check_period (ehci, frame, uframe + qh->gap_uf,
qh->period, qh->c_usecs))
goto done;
retval = 0;
}
#endif
done:
return retval;
}
/* "first fit" scheduling policy used the first time through,
* or when the previous schedule slot can't be re-used.
*/
static int qh_schedule(struct ehci_hcd *ehci, struct ehci_qh *qh)
{
int status;
unsigned uframe;
__hc32 c_mask;
unsigned frame; /* 0..(qh->period - 1), or NO_FRAME */
struct ehci_qh_hw *hw = qh->hw;
qh_refresh(ehci, qh);
hw->hw_next = EHCI_LIST_END(ehci);
frame = qh->start;
/* reuse the previous schedule slots, if we can */
if (frame < qh->period) {
uframe = ffs(hc32_to_cpup(ehci, &hw->hw_info2) & QH_SMASK);
status = check_intr_schedule (ehci, frame, --uframe,
qh, &c_mask);
} else {
uframe = 0;
c_mask = 0;
status = -ENOSPC;
}
/* else scan the schedule to find a group of slots such that all
* uframes have enough periodic bandwidth available.
*/
if (status) {
/* "normal" case, uframing flexible except with splits */
if (qh->period) {
int i;
for (i = qh->period; status && i > 0; --i) {
frame = ++ehci->random_frame % qh->period;
for (uframe = 0; uframe < 8; uframe++) {
status = check_intr_schedule (ehci,
frame, uframe, qh,
&c_mask);
if (status == 0)
break;
}
}
/* qh->period == 0 means every uframe */
} else {
frame = 0;
status = check_intr_schedule (ehci, 0, 0, qh, &c_mask);
}
if (status)
goto done;
qh->start = frame;
/* reset S-frame and (maybe) C-frame masks */
hw->hw_info2 &= cpu_to_hc32(ehci, ~(QH_CMASK | QH_SMASK));
hw->hw_info2 |= qh->period
? cpu_to_hc32(ehci, 1 << uframe)
: cpu_to_hc32(ehci, QH_SMASK);
hw->hw_info2 |= c_mask;
} else
ehci_dbg (ehci, "reused qh %p schedule\n", qh);
/* stuff into the periodic schedule */
qh_link_periodic(ehci, qh);
done:
return status;
}
static int intr_submit (
struct ehci_hcd *ehci,
struct urb *urb,
struct list_head *qtd_list,
gfp_t mem_flags
) {
unsigned epnum;
unsigned long flags;
struct ehci_qh *qh;
int status;
struct list_head empty;
/* get endpoint and transfer/schedule data */
epnum = urb->ep->desc.bEndpointAddress;
spin_lock_irqsave (&ehci->lock, flags);
if (unlikely(!HCD_HW_ACCESSIBLE(ehci_to_hcd(ehci)))) {
status = -ESHUTDOWN;
goto done_not_linked;
}
status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
if (unlikely(status))
goto done_not_linked;
/* get qh and force any scheduling errors */
INIT_LIST_HEAD (&empty);
qh = qh_append_tds(ehci, urb, &empty, epnum, &urb->ep->hcpriv);
if (qh == NULL) {
status = -ENOMEM;
goto done;
}
if (qh->qh_state == QH_STATE_IDLE) {
if ((status = qh_schedule (ehci, qh)) != 0)
goto done;
}
/* then queue the urb's tds to the qh */
qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
BUG_ON (qh == NULL);
/* ... update usbfs periodic stats */
ehci_to_hcd(ehci)->self.bandwidth_int_reqs++;
done:
if (unlikely(status))
usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
done_not_linked:
spin_unlock_irqrestore (&ehci->lock, flags);
if (status)
qtd_list_free (ehci, urb, qtd_list);
return status;
}
/*-------------------------------------------------------------------------*/
/* ehci_iso_stream ops work with both ITD and SITD */
static struct ehci_iso_stream *
iso_stream_alloc (gfp_t mem_flags)
{
struct ehci_iso_stream *stream;
stream = kzalloc(sizeof *stream, mem_flags);
if (likely (stream != NULL)) {
INIT_LIST_HEAD(&stream->td_list);
INIT_LIST_HEAD(&stream->free_list);
stream->next_uframe = -1;
stream->refcount = 1;
}
return stream;
}
static void
iso_stream_init (
struct ehci_hcd *ehci,
struct ehci_iso_stream *stream,
struct usb_device *dev,
int pipe,
unsigned interval
)
{
static const u8 smask_out [] = { 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f };
u32 buf1;
unsigned epnum, maxp;
int is_input;
long bandwidth;
/*
* this might be a "high bandwidth" highspeed endpoint,
* as encoded in the ep descriptor's wMaxPacket field
*/
epnum = usb_pipeendpoint (pipe);
is_input = usb_pipein (pipe) ? USB_DIR_IN : 0;
maxp = usb_maxpacket(dev, pipe, !is_input);
if (is_input) {
buf1 = (1 << 11);
} else {
buf1 = 0;
}
/* knows about ITD vs SITD */
if (dev->speed == USB_SPEED_HIGH) {
unsigned multi = hb_mult(maxp);
stream->highspeed = 1;
maxp = max_packet(maxp);
buf1 |= maxp;
maxp *= multi;
stream->buf0 = cpu_to_hc32(ehci, (epnum << 8) | dev->devnum);
stream->buf1 = cpu_to_hc32(ehci, buf1);
stream->buf2 = cpu_to_hc32(ehci, multi);
/* usbfs wants to report the average usecs per frame tied up
* when transfers on this endpoint are scheduled ...
*/
stream->usecs = HS_USECS_ISO (maxp);
bandwidth = stream->usecs * 8;
bandwidth /= interval;
} else {
u32 addr;
int think_time;
int hs_transfers;
addr = dev->ttport << 24;
if (!ehci_is_TDI(ehci)
|| (dev->tt->hub !=
ehci_to_hcd(ehci)->self.root_hub))
addr |= dev->tt->hub->devnum << 16;
addr |= epnum << 8;
addr |= dev->devnum;
stream->usecs = HS_USECS_ISO (maxp);
think_time = dev->tt ? dev->tt->think_time : 0;
stream->tt_usecs = NS_TO_US (think_time + usb_calc_bus_time (
dev->speed, is_input, 1, maxp));
hs_transfers = max (1u, (maxp + 187) / 188);
if (is_input) {
u32 tmp;
addr |= 1 << 31;
stream->c_usecs = stream->usecs;
stream->usecs = HS_USECS_ISO (1);
stream->raw_mask = 1;
/* c-mask as specified in USB 2.0 11.18.4 3.c */
tmp = (1 << (hs_transfers + 2)) - 1;
stream->raw_mask |= tmp << (8 + 2);
} else
stream->raw_mask = smask_out [hs_transfers - 1];
bandwidth = stream->usecs + stream->c_usecs;
bandwidth /= interval << 3;
/* stream->splits gets created from raw_mask later */
stream->address = cpu_to_hc32(ehci, addr);
}
stream->bandwidth = bandwidth;
stream->udev = dev;
stream->bEndpointAddress = is_input | epnum;
stream->interval = interval;
stream->maxp = maxp;
}
static void
iso_stream_put(struct ehci_hcd *ehci, struct ehci_iso_stream *stream)
{
stream->refcount--;
/* free whenever just a dev->ep reference remains.
* not like a QH -- no persistent state (toggle, halt)
*/
if (stream->refcount == 1) {
// BUG_ON (!list_empty(&stream->td_list));
if (stream->ep)
stream->ep->hcpriv = NULL;
kfree(stream);
}
}
static inline struct ehci_iso_stream *
iso_stream_get (struct ehci_iso_stream *stream)
{
if (likely (stream != NULL))
stream->refcount++;
return stream;
}
static struct ehci_iso_stream *
iso_stream_find (struct ehci_hcd *ehci, struct urb *urb)
{
unsigned epnum;
struct ehci_iso_stream *stream;
struct usb_host_endpoint *ep;
unsigned long flags;
epnum = usb_pipeendpoint (urb->pipe);
if (usb_pipein(urb->pipe))
ep = urb->dev->ep_in[epnum];
else
ep = urb->dev->ep_out[epnum];
spin_lock_irqsave (&ehci->lock, flags);
stream = ep->hcpriv;
if (unlikely (stream == NULL)) {
stream = iso_stream_alloc(GFP_ATOMIC);
if (likely (stream != NULL)) {
/* dev->ep owns the initial refcount */
ep->hcpriv = stream;
stream->ep = ep;
iso_stream_init(ehci, stream, urb->dev, urb->pipe,
urb->interval);
}
/* if dev->ep [epnum] is a QH, hw is set */
} else if (unlikely (stream->hw != NULL)) {
ehci_dbg (ehci, "dev %s ep%d%s, not iso??\n",
urb->dev->devpath, epnum,
usb_pipein(urb->pipe) ? "in" : "out");
stream = NULL;
}
/* caller guarantees an eventual matching iso_stream_put */
stream = iso_stream_get (stream);
spin_unlock_irqrestore (&ehci->lock, flags);
return stream;
}
/*-------------------------------------------------------------------------*/
/* ehci_iso_sched ops can be ITD-only or SITD-only */
static struct ehci_iso_sched *
iso_sched_alloc (unsigned packets, gfp_t mem_flags)
{
struct ehci_iso_sched *iso_sched;
int size = sizeof *iso_sched;
size += packets * sizeof (struct ehci_iso_packet);
iso_sched = kzalloc(size, mem_flags);
if (likely (iso_sched != NULL)) {
INIT_LIST_HEAD (&iso_sched->td_list);
}
return iso_sched;
}
static inline void
itd_sched_init(
struct ehci_hcd *ehci,
struct ehci_iso_sched *iso_sched,
struct ehci_iso_stream *stream,
struct urb *urb
)
{
unsigned i;
dma_addr_t dma = urb->transfer_dma;
/* how many uframes are needed for these transfers */
iso_sched->span = urb->number_of_packets * stream->interval;
/* figure out per-uframe itd fields that we'll need later
* when we fit new itds into the schedule.
*/
for (i = 0; i < urb->number_of_packets; i++) {
struct ehci_iso_packet *uframe = &iso_sched->packet [i];
unsigned length;
dma_addr_t buf;
u32 trans;
length = urb->iso_frame_desc [i].length;
buf = dma + urb->iso_frame_desc [i].offset;
trans = EHCI_ISOC_ACTIVE;
trans |= buf & 0x0fff;
if (unlikely (((i + 1) == urb->number_of_packets))
&& !(urb->transfer_flags & URB_NO_INTERRUPT))
trans |= EHCI_ITD_IOC;
trans |= length << 16;
uframe->transaction = cpu_to_hc32(ehci, trans);
/* might need to cross a buffer page within a uframe */
uframe->bufp = (buf & ~(u64)0x0fff);
buf += length;
if (unlikely ((uframe->bufp != (buf & ~(u64)0x0fff))))
uframe->cross = 1;
}
}
static void
iso_sched_free (
struct ehci_iso_stream *stream,
struct ehci_iso_sched *iso_sched
)
{
if (!iso_sched)
return;
// caller must hold ehci->lock!
list_splice (&iso_sched->td_list, &stream->free_list);
kfree (iso_sched);
}
static int
itd_urb_transaction (
struct ehci_iso_stream *stream,
struct ehci_hcd *ehci,
struct urb *urb,
gfp_t mem_flags
)
{
struct ehci_itd *itd;
dma_addr_t itd_dma;
int i;
unsigned num_itds;
struct ehci_iso_sched *sched;
unsigned long flags;
sched = iso_sched_alloc (urb->number_of_packets, mem_flags);
if (unlikely (sched == NULL))
return -ENOMEM;
itd_sched_init(ehci, sched, stream, urb);
if (urb->interval < 8)
num_itds = 1 + (sched->span + 7) / 8;
else
num_itds = urb->number_of_packets;
/* allocate/init ITDs */
spin_lock_irqsave (&ehci->lock, flags);
for (i = 0; i < num_itds; i++) {
/*
* Use iTDs from the free list, but not iTDs that may
* still be in use by the hardware.
*/
if (likely(!list_empty(&stream->free_list))) {
itd = list_first_entry(&stream->free_list,
struct ehci_itd, itd_list);
if (itd->frame == ehci->clock_frame)
goto alloc_itd;
list_del (&itd->itd_list);
itd_dma = itd->itd_dma;
} else {
alloc_itd:
spin_unlock_irqrestore (&ehci->lock, flags);
itd = dma_pool_alloc (ehci->itd_pool, mem_flags,
&itd_dma);
spin_lock_irqsave (&ehci->lock, flags);
if (!itd) {
iso_sched_free(stream, sched);
spin_unlock_irqrestore(&ehci->lock, flags);
return -ENOMEM;
}
}
memset (itd, 0, sizeof *itd);
itd->itd_dma = itd_dma;
list_add (&itd->itd_list, &sched->td_list);
}
spin_unlock_irqrestore (&ehci->lock, flags);
/* temporarily store schedule info in hcpriv */
urb->hcpriv = sched;
urb->error_count = 0;
return 0;
}
/*-------------------------------------------------------------------------*/
static inline int
itd_slot_ok (
struct ehci_hcd *ehci,
u32 mod,
u32 uframe,
u8 usecs,
u32 period
)
{
uframe %= period;
do {
/* can't commit more than uframe_periodic_max usec */
if (periodic_usecs (ehci, uframe >> 3, uframe & 0x7)
> (ehci->uframe_periodic_max - usecs))
return 0;
/* we know urb->interval is 2^N uframes */
uframe += period;
} while (uframe < mod);
return 1;
}
static inline int
sitd_slot_ok (
struct ehci_hcd *ehci,
u32 mod,
struct ehci_iso_stream *stream,
u32 uframe,
struct ehci_iso_sched *sched,
u32 period_uframes
)
{
u32 mask, tmp;
u32 frame, uf;
mask = stream->raw_mask << (uframe & 7);
/* for IN, don't wrap CSPLIT into the next frame */
if (mask & ~0xffff)
return 0;
/* check bandwidth */
uframe %= period_uframes;
frame = uframe >> 3;
#ifdef CONFIG_USB_EHCI_TT_NEWSCHED
/* The tt's fullspeed bus bandwidth must be available.
* tt_available scheduling guarantees 10+% for control/bulk.
*/
uf = uframe & 7;
if (!tt_available(ehci, period_uframes >> 3,
stream->udev, frame, uf, stream->tt_usecs))
return 0;
#else
/* tt must be idle for start(s), any gap, and csplit.
* assume scheduling slop leaves 10+% for control/bulk.
*/
if (!tt_no_collision(ehci, period_uframes >> 3,
stream->udev, frame, mask))
return 0;
#endif
/* this multi-pass logic is simple, but performance may
* suffer when the schedule data isn't cached.
*/
do {
u32 max_used;
frame = uframe >> 3;
uf = uframe & 7;
/* check starts (OUT uses more than one) */
max_used = ehci->uframe_periodic_max - stream->usecs;
for (tmp = stream->raw_mask & 0xff; tmp; tmp >>= 1, uf++) {
if (periodic_usecs (ehci, frame, uf) > max_used)
return 0;
}
/* for IN, check CSPLIT */
if (stream->c_usecs) {
uf = uframe & 7;
max_used = ehci->uframe_periodic_max - stream->c_usecs;
do {
tmp = 1 << uf;
tmp <<= 8;
if ((stream->raw_mask & tmp) == 0)
continue;
if (periodic_usecs (ehci, frame, uf)
> max_used)
return 0;
} while (++uf < 8);
}
/* we know urb->interval is 2^N uframes */
uframe += period_uframes;
} while (uframe < mod);
stream->splits = cpu_to_hc32(ehci, stream->raw_mask << (uframe & 7));
return 1;
}
/*
* This scheduler plans almost as far into the future as it has actual
* periodic schedule slots. (Affected by TUNE_FLS, which defaults to
* "as small as possible" to be cache-friendlier.) That limits the size
* transfers you can stream reliably; avoid more than 64 msec per urb.
* Also avoid queue depths of less than ehci's worst irq latency (affected
* by the per-urb URB_NO_INTERRUPT hint, the log2_irq_thresh module parameter,
* and other factors); or more than about 230 msec total (for portability,
* given EHCI_TUNE_FLS and the slop). Or, write a smarter scheduler!
*/
#define SCHEDULE_SLOP 80 /* microframes */
static int
iso_stream_schedule (
struct ehci_hcd *ehci,
struct urb *urb,
struct ehci_iso_stream *stream
)
{
u32 now, next, start, period, span;
int status;
unsigned mod = ehci->periodic_size << 3;
struct ehci_iso_sched *sched = urb->hcpriv;
period = urb->interval;
span = sched->span;
if (!stream->highspeed) {
period <<= 3;
span <<= 3;
}
if (span > mod - SCHEDULE_SLOP) {
ehci_dbg (ehci, "iso request %p too long\n", urb);
status = -EFBIG;
goto fail;
}
now = ehci_read_frame_index(ehci) & (mod - 1);
/* Typical case: reuse current schedule, stream is still active.
* Hopefully there are no gaps from the host falling behind
* (irq delays etc), but if there are we'll take the next
* slot in the schedule, implicitly assuming URB_ISO_ASAP.
*/
if (likely (!list_empty (&stream->td_list))) {
u32 excess;
/* For high speed devices, allow scheduling within the
* isochronous scheduling threshold. For full speed devices
* and Intel PCI-based controllers, don't (work around for
* Intel ICH9 bug).
*/
if (!stream->highspeed && ehci->fs_i_thresh)
next = now + ehci->i_thresh;
else
next = now;
/* Fell behind (by up to twice the slop amount)?
* We decide based on the time of the last currently-scheduled
* slot, not the time of the next available slot.
*/
excess = (stream->next_uframe - period - next) & (mod - 1);
if (excess >= mod - 2 * SCHEDULE_SLOP)
start = next + excess - mod + period *
DIV_ROUND_UP(mod - excess, period);
else
start = next + excess + period;
if (start - now >= mod) {
ehci_dbg(ehci, "request %p would overflow (%d+%d >= %d)\n",
urb, start - now - period, period,
mod);
status = -EFBIG;
goto fail;
}
}
/* need to schedule; when's the next (u)frame we could start?
* this is bigger than ehci->i_thresh allows; scheduling itself
* isn't free, the slop should handle reasonably slow cpus. it
* can also help high bandwidth if the dma and irq loads don't
* jump until after the queue is primed.
*/
else {
int done = 0;
start = SCHEDULE_SLOP + (now & ~0x07);
/* NOTE: assumes URB_ISO_ASAP, to limit complexity/bugs */
/* find a uframe slot with enough bandwidth.
* Early uframes are more precious because full-speed
* iso IN transfers can't use late uframes,
* and therefore they should be allocated last.
*/
next = start;
start += period;
do {
start--;
/* check schedule: enough space? */
if (stream->highspeed) {
if (itd_slot_ok(ehci, mod, start,
stream->usecs, period))
done = 1;
} else {
if ((start % 8) >= 6)
continue;
if (sitd_slot_ok(ehci, mod, stream,
start, sched, period))
done = 1;
}
} while (start > next && !done);
/* no room in the schedule */
if (!done) {
ehci_dbg(ehci, "iso resched full %p (now %d max %d)\n",
urb, now, now + mod);
status = -ENOSPC;
goto fail;
}
}
/* Tried to schedule too far into the future? */
if (unlikely(start - now + span - period
>= mod - 2 * SCHEDULE_SLOP)) {
ehci_dbg(ehci, "request %p would overflow (%d+%d >= %d)\n",
urb, start - now, span - period,
mod - 2 * SCHEDULE_SLOP);
status = -EFBIG;
goto fail;
}
stream->next_uframe = start & (mod - 1);
/* report high speed start in uframes; full speed, in frames */
urb->start_frame = stream->next_uframe;
if (!stream->highspeed)
urb->start_frame >>= 3;
return 0;
fail:
iso_sched_free(stream, sched);
urb->hcpriv = NULL;
return status;
}
/*-------------------------------------------------------------------------*/
static inline void
itd_init(struct ehci_hcd *ehci, struct ehci_iso_stream *stream,
struct ehci_itd *itd)
{
int i;
/* it's been recently zeroed */
itd->hw_next = EHCI_LIST_END(ehci);
itd->hw_bufp [0] = stream->buf0;
itd->hw_bufp [1] = stream->buf1;
itd->hw_bufp [2] = stream->buf2;
for (i = 0; i < 8; i++)
itd->index[i] = -1;
/* All other fields are filled when scheduling */
}
static inline void
itd_patch(
struct ehci_hcd *ehci,
struct ehci_itd *itd,
struct ehci_iso_sched *iso_sched,
unsigned index,
u16 uframe
)
{
struct ehci_iso_packet *uf = &iso_sched->packet [index];
unsigned pg = itd->pg;
// BUG_ON (pg == 6 && uf->cross);
uframe &= 0x07;
itd->index [uframe] = index;
itd->hw_transaction[uframe] = uf->transaction;
itd->hw_transaction[uframe] |= cpu_to_hc32(ehci, pg << 12);
itd->hw_bufp[pg] |= cpu_to_hc32(ehci, uf->bufp & ~(u32)0);
itd->hw_bufp_hi[pg] |= cpu_to_hc32(ehci, (u32)(uf->bufp >> 32));
/* iso_frame_desc[].offset must be strictly increasing */
if (unlikely (uf->cross)) {
u64 bufp = uf->bufp + 4096;
itd->pg = ++pg;
itd->hw_bufp[pg] |= cpu_to_hc32(ehci, bufp & ~(u32)0);
itd->hw_bufp_hi[pg] |= cpu_to_hc32(ehci, (u32)(bufp >> 32));
}
}
static inline void
itd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_itd *itd)
{
union ehci_shadow *prev = &ehci->pshadow[frame];
__hc32 *hw_p = &ehci->periodic[frame];
union ehci_shadow here = *prev;
__hc32 type = 0;
/* skip any iso nodes which might belong to previous microframes */
while (here.ptr) {
type = Q_NEXT_TYPE(ehci, *hw_p);
if (type == cpu_to_hc32(ehci, Q_TYPE_QH))
break;
prev = periodic_next_shadow(ehci, prev, type);
hw_p = shadow_next_periodic(ehci, &here, type);
here = *prev;
}
itd->itd_next = here;
itd->hw_next = *hw_p;
prev->itd = itd;
itd->frame = frame;
wmb ();
*hw_p = cpu_to_hc32(ehci, itd->itd_dma | Q_TYPE_ITD);
}
/* fit urb's itds into the selected schedule slot; activate as needed */
static void itd_link_urb(
struct ehci_hcd *ehci,
struct urb *urb,
unsigned mod,
struct ehci_iso_stream *stream
)
{
int packet;
unsigned next_uframe, uframe, frame;
struct ehci_iso_sched *iso_sched = urb->hcpriv;
struct ehci_itd *itd;
next_uframe = stream->next_uframe & (mod - 1);
if (unlikely (list_empty(&stream->td_list))) {
ehci_to_hcd(ehci)->self.bandwidth_allocated
+= stream->bandwidth;
ehci_vdbg (ehci,
"schedule devp %s ep%d%s-iso period %d start %d.%d\n",
urb->dev->devpath, stream->bEndpointAddress & 0x0f,
(stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
urb->interval,
next_uframe >> 3, next_uframe & 0x7);
}
if (ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs == 0) {
if (ehci->amd_pll_fix == 1)
usb_amd_quirk_pll_disable();
}
ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs++;
/* fill iTDs uframe by uframe */
for (packet = 0, itd = NULL; packet < urb->number_of_packets; ) {
if (itd == NULL) {
/* ASSERT: we have all necessary itds */
// BUG_ON (list_empty (&iso_sched->td_list));
/* ASSERT: no itds for this endpoint in this uframe */
itd = list_entry (iso_sched->td_list.next,
struct ehci_itd, itd_list);
list_move_tail (&itd->itd_list, &stream->td_list);
itd->stream = iso_stream_get (stream);
itd->urb = urb;
itd_init (ehci, stream, itd);
}
uframe = next_uframe & 0x07;
frame = next_uframe >> 3;
itd_patch(ehci, itd, iso_sched, packet, uframe);
next_uframe += stream->interval;
next_uframe &= mod - 1;
packet++;
/* link completed itds into the schedule */
if (((next_uframe >> 3) != frame)
|| packet == urb->number_of_packets) {
itd_link(ehci, frame & (ehci->periodic_size - 1), itd);
itd = NULL;
}
}
stream->next_uframe = next_uframe;
/* don't need that schedule data any more */
iso_sched_free (stream, iso_sched);
urb->hcpriv = NULL;
timer_action (ehci, TIMER_IO_WATCHDOG);
enable_periodic(ehci);
}
#define ISO_ERRS (EHCI_ISOC_BUF_ERR | EHCI_ISOC_BABBLE | EHCI_ISOC_XACTERR)
/* Process and recycle a completed ITD. Return true iff its urb completed,
* and hence its completion callback probably added things to the hardware
* schedule.
*
* Note that we carefully avoid recycling this descriptor until after any
* completion callback runs, so that it won't be reused quickly. That is,
* assuming (a) no more than two urbs per frame on this endpoint, and also
* (b) only this endpoint's completions submit URBs. It seems some silicon
* corrupts things if you reuse completed descriptors very quickly...
*/
static unsigned
itd_complete (
struct ehci_hcd *ehci,
struct ehci_itd *itd
) {
struct urb *urb = itd->urb;
struct usb_iso_packet_descriptor *desc;
u32 t;
unsigned uframe;
int urb_index = -1;
struct ehci_iso_stream *stream = itd->stream;
struct usb_device *dev;
unsigned retval = false;
/* for each uframe with a packet */
for (uframe = 0; uframe < 8; uframe++) {
if (likely (itd->index[uframe] == -1))
continue;
urb_index = itd->index[uframe];
desc = &urb->iso_frame_desc [urb_index];
t = hc32_to_cpup(ehci, &itd->hw_transaction [uframe]);
itd->hw_transaction [uframe] = 0;
/* report transfer status */
if (unlikely (t & ISO_ERRS)) {
urb->error_count++;
if (t & EHCI_ISOC_BUF_ERR)
desc->status = usb_pipein (urb->pipe)
? -ENOSR /* hc couldn't read */
: -ECOMM; /* hc couldn't write */
else if (t & EHCI_ISOC_BABBLE)
desc->status = -EOVERFLOW;
else /* (t & EHCI_ISOC_XACTERR) */
desc->status = -EPROTO;
/* HC need not update length with this error */
if (!(t & EHCI_ISOC_BABBLE)) {
desc->actual_length = EHCI_ITD_LENGTH(t);
urb->actual_length += desc->actual_length;
}
} else if (likely ((t & EHCI_ISOC_ACTIVE) == 0)) {
desc->status = 0;
desc->actual_length = EHCI_ITD_LENGTH(t);
urb->actual_length += desc->actual_length;
} else {
/* URB was too late */
desc->status = -EXDEV;
}
}
/* handle completion now? */
if (likely ((urb_index + 1) != urb->number_of_packets))
goto done;
/* ASSERT: it's really the last itd for this urb
list_for_each_entry (itd, &stream->td_list, itd_list)
BUG_ON (itd->urb == urb);
*/
/* give urb back to the driver; completion often (re)submits */
dev = urb->dev;
ehci_urb_done(ehci, urb, 0);
retval = true;
urb = NULL;
disable_periodic(ehci);
ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
if (ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs == 0) {
if (ehci->amd_pll_fix == 1)
usb_amd_quirk_pll_enable();
}
if (unlikely(list_is_singular(&stream->td_list))) {
ehci_to_hcd(ehci)->self.bandwidth_allocated
-= stream->bandwidth;
ehci_vdbg (ehci,
"deschedule devp %s ep%d%s-iso\n",
dev->devpath, stream->bEndpointAddress & 0x0f,
(stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
}
iso_stream_put (ehci, stream);
done:
itd->urb = NULL;
/* Add to the end of the free list for later reuse */
list_move_tail(&itd->itd_list, &stream->free_list);
/* Recycle the iTDs when the pipeline is empty (ep no longer in use) */
if (list_empty(&stream->td_list)) {
list_splice_tail_init(&stream->free_list,
&ehci->cached_itd_list);
start_free_itds(ehci);
}
iso_stream_put(ehci, stream);
return retval;
}
/*-------------------------------------------------------------------------*/
static int itd_submit (struct ehci_hcd *ehci, struct urb *urb,
gfp_t mem_flags)
{
int status = -EINVAL;
unsigned long flags;
struct ehci_iso_stream *stream;
/* Get iso_stream head */
stream = iso_stream_find (ehci, urb);
if (unlikely (stream == NULL)) {
ehci_dbg (ehci, "can't get iso stream\n");
return -ENOMEM;
}
if (unlikely (urb->interval != stream->interval)) {
ehci_dbg (ehci, "can't change iso interval %d --> %d\n",
stream->interval, urb->interval);
goto done;
}
#ifdef EHCI_URB_TRACE
ehci_dbg (ehci,
"%s %s urb %p ep%d%s len %d, %d pkts %d uframes [%p]\n",
__func__, urb->dev->devpath, urb,
usb_pipeendpoint (urb->pipe),
usb_pipein (urb->pipe) ? "in" : "out",
urb->transfer_buffer_length,
urb->number_of_packets, urb->interval,
stream);
#endif
/* allocate ITDs w/o locking anything */
status = itd_urb_transaction (stream, ehci, urb, mem_flags);
if (unlikely (status < 0)) {
ehci_dbg (ehci, "can't init itds\n");
goto done;
}
/* schedule ... need to lock */
spin_lock_irqsave (&ehci->lock, flags);
if (unlikely(!HCD_HW_ACCESSIBLE(ehci_to_hcd(ehci)))) {
status = -ESHUTDOWN;
goto done_not_linked;
}
status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
if (unlikely(status))
goto done_not_linked;
status = iso_stream_schedule(ehci, urb, stream);
if (likely (status == 0))
itd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
else
usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
done_not_linked:
spin_unlock_irqrestore (&ehci->lock, flags);
done:
if (unlikely (status < 0))
iso_stream_put (ehci, stream);
return status;
}
/*-------------------------------------------------------------------------*/
/*
* "Split ISO TDs" ... used for USB 1.1 devices going through the
* TTs in USB 2.0 hubs. These need microframe scheduling.
*/
static inline void
sitd_sched_init(
struct ehci_hcd *ehci,
struct ehci_iso_sched *iso_sched,
struct ehci_iso_stream *stream,
struct urb *urb
)
{
unsigned i;
dma_addr_t dma = urb->transfer_dma;
/* how many frames are needed for these transfers */
iso_sched->span = urb->number_of_packets * stream->interval;
/* figure out per-frame sitd fields that we'll need later
* when we fit new sitds into the schedule.
*/
for (i = 0; i < urb->number_of_packets; i++) {
struct ehci_iso_packet *packet = &iso_sched->packet [i];
unsigned length;
dma_addr_t buf;
u32 trans;
length = urb->iso_frame_desc [i].length & 0x03ff;
buf = dma + urb->iso_frame_desc [i].offset;
trans = SITD_STS_ACTIVE;
if (((i + 1) == urb->number_of_packets)
&& !(urb->transfer_flags & URB_NO_INTERRUPT))
trans |= SITD_IOC;
trans |= length << 16;
packet->transaction = cpu_to_hc32(ehci, trans);
/* might need to cross a buffer page within a td */
packet->bufp = buf;
packet->buf1 = (buf + length) & ~0x0fff;
if (packet->buf1 != (buf & ~(u64)0x0fff))
packet->cross = 1;
/* OUT uses multiple start-splits */
if (stream->bEndpointAddress & USB_DIR_IN)
continue;
length = (length + 187) / 188;
if (length > 1) /* BEGIN vs ALL */
length |= 1 << 3;
packet->buf1 |= length;
}
}
static int
sitd_urb_transaction (
struct ehci_iso_stream *stream,
struct ehci_hcd *ehci,
struct urb *urb,
gfp_t mem_flags
)
{
struct ehci_sitd *sitd;
dma_addr_t sitd_dma;
int i;
struct ehci_iso_sched *iso_sched;
unsigned long flags;
iso_sched = iso_sched_alloc (urb->number_of_packets, mem_flags);
if (iso_sched == NULL)
return -ENOMEM;
sitd_sched_init(ehci, iso_sched, stream, urb);
/* allocate/init sITDs */
spin_lock_irqsave (&ehci->lock, flags);
for (i = 0; i < urb->number_of_packets; i++) {
/* NOTE: for now, we don't try to handle wraparound cases
* for IN (using sitd->hw_backpointer, like a FSTN), which
* means we never need two sitds for full speed packets.
*/
/*
* Use siTDs from the free list, but not siTDs that may
* still be in use by the hardware.
*/
if (likely(!list_empty(&stream->free_list))) {
sitd = list_first_entry(&stream->free_list,
struct ehci_sitd, sitd_list);
if (sitd->frame == ehci->clock_frame)
goto alloc_sitd;
list_del (&sitd->sitd_list);
sitd_dma = sitd->sitd_dma;
} else {
alloc_sitd:
spin_unlock_irqrestore (&ehci->lock, flags);
sitd = dma_pool_alloc (ehci->sitd_pool, mem_flags,
&sitd_dma);
spin_lock_irqsave (&ehci->lock, flags);
if (!sitd) {
iso_sched_free(stream, iso_sched);
spin_unlock_irqrestore(&ehci->lock, flags);
return -ENOMEM;
}
}
memset (sitd, 0, sizeof *sitd);
sitd->sitd_dma = sitd_dma;
list_add (&sitd->sitd_list, &iso_sched->td_list);
}
/* temporarily store schedule info in hcpriv */
urb->hcpriv = iso_sched;
urb->error_count = 0;
spin_unlock_irqrestore (&ehci->lock, flags);
return 0;
}
/*-------------------------------------------------------------------------*/
static inline void
sitd_patch(
struct ehci_hcd *ehci,
struct ehci_iso_stream *stream,
struct ehci_sitd *sitd,
struct ehci_iso_sched *iso_sched,
unsigned index
)
{
struct ehci_iso_packet *uf = &iso_sched->packet [index];
u64 bufp = uf->bufp;
sitd->hw_next = EHCI_LIST_END(ehci);
sitd->hw_fullspeed_ep = stream->address;
sitd->hw_uframe = stream->splits;
sitd->hw_results = uf->transaction;
sitd->hw_backpointer = EHCI_LIST_END(ehci);
bufp = uf->bufp;
sitd->hw_buf[0] = cpu_to_hc32(ehci, bufp);
sitd->hw_buf_hi[0] = cpu_to_hc32(ehci, bufp >> 32);
sitd->hw_buf[1] = cpu_to_hc32(ehci, uf->buf1);
if (uf->cross)
bufp += 4096;
sitd->hw_buf_hi[1] = cpu_to_hc32(ehci, bufp >> 32);
sitd->index = index;
}
static inline void
sitd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_sitd *sitd)
{
/* note: sitd ordering could matter (CSPLIT then SSPLIT) */
sitd->sitd_next = ehci->pshadow [frame];
sitd->hw_next = ehci->periodic [frame];
ehci->pshadow [frame].sitd = sitd;
sitd->frame = frame;
wmb ();
ehci->periodic[frame] = cpu_to_hc32(ehci, sitd->sitd_dma | Q_TYPE_SITD);
}
/* fit urb's sitds into the selected schedule slot; activate as needed */
static void sitd_link_urb(
struct ehci_hcd *ehci,
struct urb *urb,
unsigned mod,
struct ehci_iso_stream *stream
)
{
int packet;
unsigned next_uframe;
struct ehci_iso_sched *sched = urb->hcpriv;
struct ehci_sitd *sitd;
next_uframe = stream->next_uframe;
if (list_empty(&stream->td_list)) {
/* usbfs ignores TT bandwidth */
ehci_to_hcd(ehci)->self.bandwidth_allocated
+= stream->bandwidth;
ehci_vdbg (ehci,
"sched devp %s ep%d%s-iso [%d] %dms/%04x\n",
urb->dev->devpath, stream->bEndpointAddress & 0x0f,
(stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
(next_uframe >> 3) & (ehci->periodic_size - 1),
stream->interval, hc32_to_cpu(ehci, stream->splits));
}
if (ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs == 0) {
if (ehci->amd_pll_fix == 1)
usb_amd_quirk_pll_disable();
}
ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs++;
/* fill sITDs frame by frame */
for (packet = 0, sitd = NULL;
packet < urb->number_of_packets;
packet++) {
/* ASSERT: we have all necessary sitds */
BUG_ON (list_empty (&sched->td_list));
/* ASSERT: no itds for this endpoint in this frame */
sitd = list_entry (sched->td_list.next,
struct ehci_sitd, sitd_list);
list_move_tail (&sitd->sitd_list, &stream->td_list);
sitd->stream = iso_stream_get (stream);
sitd->urb = urb;
sitd_patch(ehci, stream, sitd, sched, packet);
sitd_link(ehci, (next_uframe >> 3) & (ehci->periodic_size - 1),
sitd);
next_uframe += stream->interval << 3;
}
stream->next_uframe = next_uframe & (mod - 1);
/* don't need that schedule data any more */
iso_sched_free (stream, sched);
urb->hcpriv = NULL;
timer_action (ehci, TIMER_IO_WATCHDOG);
enable_periodic(ehci);
}
/*-------------------------------------------------------------------------*/
#define SITD_ERRS (SITD_STS_ERR | SITD_STS_DBE | SITD_STS_BABBLE \
| SITD_STS_XACT | SITD_STS_MMF)
/* Process and recycle a completed SITD. Return true iff its urb completed,
* and hence its completion callback probably added things to the hardware
* schedule.
*
* Note that we carefully avoid recycling this descriptor until after any
* completion callback runs, so that it won't be reused quickly. That is,
* assuming (a) no more than two urbs per frame on this endpoint, and also
* (b) only this endpoint's completions submit URBs. It seems some silicon
* corrupts things if you reuse completed descriptors very quickly...
*/
static unsigned
sitd_complete (
struct ehci_hcd *ehci,
struct ehci_sitd *sitd
) {
struct urb *urb = sitd->urb;
struct usb_iso_packet_descriptor *desc;
u32 t;
int urb_index = -1;
struct ehci_iso_stream *stream = sitd->stream;
struct usb_device *dev;
unsigned retval = false;
urb_index = sitd->index;
desc = &urb->iso_frame_desc [urb_index];
t = hc32_to_cpup(ehci, &sitd->hw_results);
/* report transfer status */
if (t & SITD_ERRS) {
urb->error_count++;
if (t & SITD_STS_DBE)
desc->status = usb_pipein (urb->pipe)
? -ENOSR /* hc couldn't read */
: -ECOMM; /* hc couldn't write */
else if (t & SITD_STS_BABBLE)
desc->status = -EOVERFLOW;
else /* XACT, MMF, etc */
desc->status = -EPROTO;
} else {
desc->status = 0;
desc->actual_length = desc->length - SITD_LENGTH(t);
urb->actual_length += desc->actual_length;
}
/* handle completion now? */
if ((urb_index + 1) != urb->number_of_packets)
goto done;
/* ASSERT: it's really the last sitd for this urb
list_for_each_entry (sitd, &stream->td_list, sitd_list)
BUG_ON (sitd->urb == urb);
*/
/* give urb back to the driver; completion often (re)submits */
dev = urb->dev;
ehci_urb_done(ehci, urb, 0);
retval = true;
urb = NULL;
disable_periodic(ehci);
ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
if (ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs == 0) {
if (ehci->amd_pll_fix == 1)
usb_amd_quirk_pll_enable();
}
if (list_is_singular(&stream->td_list)) {
ehci_to_hcd(ehci)->self.bandwidth_allocated
-= stream->bandwidth;
ehci_vdbg (ehci,
"deschedule devp %s ep%d%s-iso\n",
dev->devpath, stream->bEndpointAddress & 0x0f,
(stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
}
iso_stream_put (ehci, stream);
done:
sitd->urb = NULL;
/* Add to the end of the free list for later reuse */
list_move_tail(&sitd->sitd_list, &stream->free_list);
/* Recycle the siTDs when the pipeline is empty (ep no longer in use) */
if (list_empty(&stream->td_list)) {
list_splice_tail_init(&stream->free_list,
&ehci->cached_sitd_list);
start_free_itds(ehci);
}
iso_stream_put(ehci, stream);
return retval;
}
static int sitd_submit (struct ehci_hcd *ehci, struct urb *urb,
gfp_t mem_flags)
{
int status = -EINVAL;
unsigned long flags;
struct ehci_iso_stream *stream;
/* Get iso_stream head */
stream = iso_stream_find (ehci, urb);
if (stream == NULL) {
ehci_dbg (ehci, "can't get iso stream\n");
return -ENOMEM;
}
if (urb->interval != stream->interval) {
ehci_dbg (ehci, "can't change iso interval %d --> %d\n",
stream->interval, urb->interval);
goto done;
}
#ifdef EHCI_URB_TRACE
ehci_dbg (ehci,
"submit %p dev%s ep%d%s-iso len %d\n",
urb, urb->dev->devpath,
usb_pipeendpoint (urb->pipe),
usb_pipein (urb->pipe) ? "in" : "out",
urb->transfer_buffer_length);
#endif
/* allocate SITDs */
status = sitd_urb_transaction (stream, ehci, urb, mem_flags);
if (status < 0) {
ehci_dbg (ehci, "can't init sitds\n");
goto done;
}
/* schedule ... need to lock */
spin_lock_irqsave (&ehci->lock, flags);
if (unlikely(!HCD_HW_ACCESSIBLE(ehci_to_hcd(ehci)))) {
status = -ESHUTDOWN;
goto done_not_linked;
}
status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
if (unlikely(status))
goto done_not_linked;
status = iso_stream_schedule(ehci, urb, stream);
if (status == 0)
sitd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
else
usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
done_not_linked:
spin_unlock_irqrestore (&ehci->lock, flags);
done:
if (status < 0)
iso_stream_put (ehci, stream);
return status;
}
/*-------------------------------------------------------------------------*/
static void
scan_periodic (struct ehci_hcd *ehci)
{
unsigned now_uframe, frame, clock, clock_frame, mod;
unsigned modified;
mod = ehci->periodic_size << 3;
/*
* When running, scan from last scan point up to "now"
* else clean up by scanning everything that's left.
* Touches as few pages as possible: cache-friendly.
*/
now_uframe = ehci->next_uframe;
if (ehci->rh_state >= EHCI_RH_RUNNING) {
clock = ehci_read_frame_index(ehci);
clock_frame = (clock >> 3) & (ehci->periodic_size - 1);
} else {
clock = now_uframe + mod - 1;
clock_frame = -1;
}
ehci->clock_frame = clock_frame;
clock &= mod - 1;
clock_frame = clock >> 3;
++ehci->periodic_stamp;
for (;;) {
union ehci_shadow q, *q_p;
__hc32 type, *hw_p;
unsigned incomplete = false;
frame = now_uframe >> 3;
restart:
/* scan each element in frame's queue for completions */
q_p = &ehci->pshadow [frame];
hw_p = &ehci->periodic [frame];
q.ptr = q_p->ptr;
type = Q_NEXT_TYPE(ehci, *hw_p);
modified = 0;
while (q.ptr != NULL) {
unsigned uf;
union ehci_shadow temp;
int live;
live = (ehci->rh_state >= EHCI_RH_RUNNING);
switch (hc32_to_cpu(ehci, type)) {
case Q_TYPE_QH:
/* handle any completions */
temp.qh = q.qh;
type = Q_NEXT_TYPE(ehci, q.qh->hw->hw_next);
q = q.qh->qh_next;
if (temp.qh->stamp != ehci->periodic_stamp) {
modified = qh_completions(ehci, temp.qh);
if (!modified)
temp.qh->stamp = ehci->periodic_stamp;
if (unlikely(list_empty(&temp.qh->qtd_list) ||
temp.qh->needs_rescan))
start_unlink_intr(ehci, temp.qh);
}
break;
case Q_TYPE_FSTN:
/* for "save place" FSTNs, look at QH entries
* in the previous frame for completions.
*/
if (q.fstn->hw_prev != EHCI_LIST_END(ehci)) {
ehci_dbg(ehci,
"ignoring completions from FSTNs\n");
}
type = Q_NEXT_TYPE(ehci, q.fstn->hw_next);
q = q.fstn->fstn_next;
break;
case Q_TYPE_ITD:
/* If this ITD is still active, leave it for
* later processing ... check the next entry.
* No need to check for activity unless the
* frame is current.
*/
if (frame == clock_frame && live) {
rmb();
for (uf = 0; uf < 8; uf++) {
if (q.itd->hw_transaction[uf] &
ITD_ACTIVE(ehci))
break;
}
if (uf < 8) {
incomplete = true;
q_p = &q.itd->itd_next;
hw_p = &q.itd->hw_next;
type = Q_NEXT_TYPE(ehci,
q.itd->hw_next);
q = *q_p;
break;
}
}
/* Take finished ITDs out of the schedule
* and process them: recycle, maybe report
* URB completion. HC won't cache the
* pointer for much longer, if at all.
*/
*q_p = q.itd->itd_next;
if (!ehci->use_dummy_qh ||
q.itd->hw_next != EHCI_LIST_END(ehci))
*hw_p = q.itd->hw_next;
else
*hw_p = ehci->dummy->qh_dma;
type = Q_NEXT_TYPE(ehci, q.itd->hw_next);
wmb();
modified = itd_complete (ehci, q.itd);
q = *q_p;
break;
case Q_TYPE_SITD:
/* If this SITD is still active, leave it for
* later processing ... check the next entry.
* No need to check for activity unless the
* frame is current.
*/
if (((frame == clock_frame) ||
(((frame + 1) & (ehci->periodic_size - 1))
== clock_frame))
&& live
&& (q.sitd->hw_results &
SITD_ACTIVE(ehci))) {
incomplete = true;
q_p = &q.sitd->sitd_next;
hw_p = &q.sitd->hw_next;
type = Q_NEXT_TYPE(ehci,
q.sitd->hw_next);
q = *q_p;
break;
}
/* Take finished SITDs out of the schedule
* and process them: recycle, maybe report
* URB completion.
*/
*q_p = q.sitd->sitd_next;
if (!ehci->use_dummy_qh ||
q.sitd->hw_next != EHCI_LIST_END(ehci))
*hw_p = q.sitd->hw_next;
else
*hw_p = ehci->dummy->qh_dma;
type = Q_NEXT_TYPE(ehci, q.sitd->hw_next);
wmb();
modified = sitd_complete (ehci, q.sitd);
q = *q_p;
break;
default:
ehci_dbg(ehci, "corrupt type %d frame %d shadow %p\n",
type, frame, q.ptr);
// BUG ();
q.ptr = NULL;
}
/* assume completion callbacks modify the queue */
if (unlikely (modified)) {
if (likely(ehci->periodic_count > 0))
goto restart;
/* short-circuit this scan */
now_uframe = clock;
break;
}
}
/* If we can tell we caught up to the hardware, stop now.
* We can't advance our scan without collecting the ISO
* transfers that are still pending in this frame.
*/
if (incomplete && ehci->rh_state >= EHCI_RH_RUNNING) {
ehci->next_uframe = now_uframe;
break;
}
// FIXME: this assumes we won't get lapped when
// latencies climb; that should be rare, but...
// detect it, and just go all the way around.
// FLR might help detect this case, so long as latencies
// don't exceed periodic_size msec (default 1.024 sec).
// FIXME: likewise assumes HC doesn't halt mid-scan
if (now_uframe == clock) {
unsigned now;
if (ehci->rh_state < EHCI_RH_RUNNING
|| ehci->periodic_count == 0)
break;
ehci->next_uframe = now_uframe;
now = ehci_read_frame_index(ehci) & (mod - 1);
if (now_uframe == now)
break;
/* rescan the rest of this frame, then ... */
clock = now;
clock_frame = clock >> 3;
if (ehci->clock_frame != clock_frame) {
ehci->clock_frame = clock_frame;
++ehci->periodic_stamp;
}
} else {
now_uframe++;
now_uframe &= mod - 1;
}
}
}
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