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linux/drivers/usb/host/ehci-sched.c
Alan Stern 88d8aa462b USB: EHCI: remove dead code in the periodic scheduler 
This patch (as1409) removes some dead code from the ehci-hcd
scheduler.  Thanks to the previous patch in this series, stream->depth
is no longer used.  And stream->start and stream->rescheduled
apparently have not been used for quite a while, except in some
statistics-reporting code that never gets invoked.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-08-10 14:35:40 -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);
/*-------------------------------------------------------------------------*/
/*
* 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));
*hw_p = *shadow_next_periodic(ehci, &here, Q_NEXT_TYPE(ehci, *hw_p));
}
/* 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 > 100)
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 int enable_periodic (struct ehci_hcd *ehci)
{
u32 cmd;
int status;
if (ehci->periodic_sched++)
return 0;
/* did clearing PSE did take effect yet?
* takes effect only at frame boundaries...
*/
status = handshake_on_error_set_halt(ehci, &ehci->regs->status,
STS_PSS, 0, 9 * 125);
if (status)
return status;
cmd = ehci_readl(ehci, &ehci->regs->command) | CMD_PSE;
ehci_writel(ehci, cmd, &ehci->regs->command);
/* posted write ... PSS happens later */
ehci_to_hcd(ehci)->state = HC_STATE_RUNNING;
/* make sure ehci_work scans these */
ehci->next_uframe = ehci_readl(ehci, &ehci->regs->frame_index)
% (ehci->periodic_size << 3);
if (unlikely(ehci->broken_periodic))
ehci->last_periodic_enable = ktime_get_real();
return 0;
}
static int disable_periodic (struct ehci_hcd *ehci)
{
u32 cmd;
int status;
if (--ehci->periodic_sched)
return 0;
if (unlikely(ehci->broken_periodic)) {
/* delay experimentally determined */
ktime_t safe = ktime_add_us(ehci->last_periodic_enable, 1000);
ktime_t now = ktime_get_real();
s64 delay = ktime_us_delta(safe, now);
if (unlikely(delay > 0))
udelay(delay);
}
/* did setting PSE not take effect yet?
* takes effect only at frame boundaries...
*/
status = handshake_on_error_set_halt(ehci, &ehci->regs->status,
STS_PSS, STS_PSS, 9 * 125);
if (status)
return status;
cmd = ehci_readl(ehci, &ehci->regs->command) & ~CMD_PSE;
ehci_writel(ehci, cmd, &ehci->regs->command);
/* posted write ... */
free_cached_lists(ehci);
ehci->next_uframe = -1;
return 0;
}
/*-------------------------------------------------------------------------*/
/* 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 int 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;
qh_get (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);
/* maybe enable periodic schedule processing */
return enable_periodic(ehci);
}
static int 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" */);
/* 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;
qh_put (qh);
/* maybe turn off periodic schedule */
return disable_periodic(ehci);
}
static void intr_deschedule (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.
*/
if (qh->qh_state != QH_STATE_LINKED) {
if (qh->qh_state == QH_STATE_COMPLETING)
qh->needs_rescan = 1;
return;
}
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...
*/
if (list_empty (&qh->qtd_list)
|| (cpu_to_hc32(ehci, QH_CMASK)
& hw->hw_info2) != 0)
wait = 2;
else
wait = 55; /* worst case: 3 * 1024 */
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) &&
HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) {
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);
}
}
/*-------------------------------------------------------------------------*/
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;
/*
* 80% periodic == 100 usec/uframe available
* convert "usecs we need" to "max already claimed"
*/
usecs = 100 - 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 */
status = 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) {
int is_in;
// BUG_ON (!list_empty(&stream->td_list));
while (!list_empty (&stream->free_list)) {
struct list_head *entry;
entry = stream->free_list.next;
list_del (entry);
/* knows about ITD vs SITD */
if (stream->highspeed) {
struct ehci_itd *itd;
itd = list_entry (entry, struct ehci_itd,
itd_list);
dma_pool_free (ehci->itd_pool, itd,
itd->itd_dma);
} else {
struct ehci_sitd *sitd;
sitd = list_entry (entry, struct ehci_sitd,
sitd_list);
dma_pool_free (ehci->sitd_pool, sitd,
sitd->sitd_dma);
}
}
is_in = (stream->bEndpointAddress & USB_DIR_IN) ? 0x10 : 0;
stream->bEndpointAddress &= 0x0f;
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++) {
/* free_list.next might be cache-hot ... but maybe
* the HC caches it too. avoid that issue for now.
*/
/* prefer previously-allocated itds */
if (likely (!list_empty(&stream->free_list))) {
itd = list_entry (stream->free_list.prev,
struct ehci_itd, itd_list);
list_del (&itd->itd_list);
itd_dma = itd->itd_dma;
} else {
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 80% periodic == 100 usec */
if (periodic_usecs (ehci, uframe >> 3, uframe & 0x7)
> (100 - 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;
/* this multi-pass logic is simple, but performance may
* suffer when the schedule data isn't cached.
*/
/* check bandwidth */
uframe %= period_uframes;
do {
u32 max_used;
frame = uframe >> 3;
uf = uframe & 7;
#ifdef CONFIG_USB_EHCI_TT_NEWSCHED
/* The tt's fullspeed bus bandwidth must be available.
* tt_available scheduling guarantees 10+% for control/bulk.
*/
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
/* check starts (OUT uses more than one) */
max_used = 100 - 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 = 100 - 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_readl(ehci, &ehci->regs->frame_index) & (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 {
start = SCHEDULE_SLOP + (now & ~0x07);
/* NOTE: assumes URB_ISO_ASAP, to limit complexity/bugs */
/* find a uframe slot with enough bandwidth */
next = start + period;
for (; start < next; start++) {
/* check schedule: enough space? */
if (stream->highspeed) {
if (itd_slot_ok(ehci, mod, start,
stream->usecs, period))
break;
} else {
if ((start % 8) >= 6)
continue;
if (sitd_slot_ok(ehci, mod, stream,
start, sched, period))
break;
}
}
/* no room in the schedule */
if (start == next) {
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 int
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);
}
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);
return 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;
(void) disable_periodic(ehci);
ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
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;
if (ehci->clock_frame != itd->frame || itd->index[7] != -1) {
/* OK to recycle this ITD now. */
itd->stream = NULL;
list_move(&itd->itd_list, &stream->free_list);
iso_stream_put(ehci, stream);
} else {
/* HW might remember this ITD, so we can't recycle it yet.
* Move it to a safe place until a new frame starts.
*/
list_move(&itd->itd_list, &ehci->cached_itd_list);
if (stream->refcount == 2) {
/* If iso_stream_put() were called here, stream
* would be freed. Instead, just prevent reuse.
*/
stream->ep->hcpriv = NULL;
stream->ep = NULL;
}
}
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.
*/
/* free_list.next might be cache-hot ... but maybe
* the HC caches it too. avoid that issue for now.
*/
/* prefer previously-allocated sitds */
if (!list_empty(&stream->free_list)) {
sitd = list_entry (stream->free_list.prev,
struct ehci_sitd, sitd_list);
list_del (&sitd->sitd_list);
sitd_dma = sitd->sitd_dma;
} else {
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 int
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));
}
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);
return 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;
(void) disable_periodic(ehci);
ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
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;
if (ehci->clock_frame != sitd->frame) {
/* OK to recycle this SITD now. */
sitd->stream = NULL;
list_move(&sitd->sitd_list, &stream->free_list);
iso_stream_put(ehci, stream);
} else {
/* HW might remember this SITD, so we can't recycle it yet.
* Move it to a safe place until a new frame starts.
*/
list_move(&sitd->sitd_list, &ehci->cached_sitd_list);
if (stream->refcount == 2) {
/* If iso_stream_put() were called here, stream
* would be freed. Instead, just prevent reuse.
*/
stream->ep->hcpriv = NULL;
stream->ep = NULL;
}
}
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 free_cached_lists(struct ehci_hcd *ehci)
{
struct ehci_itd *itd, *n;
struct ehci_sitd *sitd, *sn;
list_for_each_entry_safe(itd, n, &ehci->cached_itd_list, itd_list) {
struct ehci_iso_stream *stream = itd->stream;
itd->stream = NULL;
list_move(&itd->itd_list, &stream->free_list);
iso_stream_put(ehci, stream);
}
list_for_each_entry_safe(sitd, sn, &ehci->cached_sitd_list, sitd_list) {
struct ehci_iso_stream *stream = sitd->stream;
sitd->stream = NULL;
list_move(&sitd->sitd_list, &stream->free_list);
iso_stream_put(ehci, stream);
}
}
/*-------------------------------------------------------------------------*/
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 (HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) {
clock = ehci_readl(ehci, &ehci->regs->frame_index);
clock_frame = (clock >> 3) & (ehci->periodic_size - 1);
} else {
clock = now_uframe + mod - 1;
clock_frame = -1;
}
if (ehci->clock_frame != clock_frame) {
free_cached_lists(ehci);
ehci->clock_frame = clock_frame;
}
clock &= mod - 1;
clock_frame = clock >> 3;
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 = HC_IS_RUNNING (ehci_to_hcd(ehci)->state);
switch (hc32_to_cpu(ehci, type)) {
case Q_TYPE_QH:
/* handle any completions */
temp.qh = qh_get (q.qh);
type = Q_NEXT_TYPE(ehci, q.qh->hw->hw_next);
q = q.qh->qh_next;
modified = qh_completions (ehci, temp.qh);
if (unlikely(list_empty(&temp.qh->qtd_list) ||
temp.qh->needs_rescan))
intr_deschedule (ehci, temp.qh);
qh_put (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)) {
dbg ("ignoring completions from FSTNs");
}
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;
*hw_p = q.itd->hw_next;
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;
*hw_p = q.sitd->hw_next;
type = Q_NEXT_TYPE(ehci, q.sitd->hw_next);
wmb();
modified = sitd_complete (ehci, q.sitd);
q = *q_p;
break;
default:
dbg ("corrupt type %d frame %d shadow %p",
type, frame, q.ptr);
// BUG ();
q.ptr = NULL;
}
/* assume completion callbacks modify the queue */
if (unlikely (modified)) {
if (likely(ehci->periodic_sched > 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 && HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) {
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 (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state)
|| ehci->periodic_sched == 0)
break;
ehci->next_uframe = now_uframe;
now = ehci_readl(ehci, &ehci->regs->frame_index) &
(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) {
free_cached_lists(ehci);
ehci->clock_frame = clock_frame;
}
} else {
now_uframe++;
now_uframe &= mod - 1;
}
}
}
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