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linux-next/drivers/usb/host/ehci-q.c
Alan Stern 6e0c3339a6 USB: EHCI: unlink one async QH at a time 
This patch (as1648) fixes a regression affecting nVidia EHCI
controllers.  Evidently they don't like to have more than one async QH
unlinked at a time.  I can't imagine how they manage to mess it up,
but at least one of them does.

The patch changes the async unlink logic in two ways:

	Each time an IAA cycle is started, only the first QH on the
	async unlink list is handled (rather than all of them).

	Async QHs do not all get unlinked as soon as they have been
	empty for long enough.  Instead, only the last one (i.e., the
	one that has been on the schedule the longest) is unlinked,
	and then only if no other unlinks are in progress at the time.

This means that when multiple QHs are empty, they won't be unlinked as
quickly as before.  That's okay; it won't affect correct operation of
the driver or add an excessive load.  Multiple unlinks tend to be
relatively rare in any case.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: Piergiorgio Sartor <piergiorgio.sartor@nexgo.de>
Cc: stable <stable@vger.kernel.org> # 3.6
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-25 13:58:20 -08:00

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/*
* Copyright (C) 2001-2004 by David Brownell
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/* this file is part of ehci-hcd.c */
/*-------------------------------------------------------------------------*/
/*
* EHCI hardware queue manipulation ... the core. QH/QTD manipulation.
*
* Control, bulk, and interrupt traffic all use "qh" lists. They list "qtd"
* entries describing USB transactions, max 16-20kB/entry (with 4kB-aligned
* buffers needed for the larger number). We use one QH per endpoint, queue
* multiple urbs (all three types) per endpoint. URBs may need several qtds.
*
* ISO traffic uses "ISO TD" (itd, and sitd) records, and (along with
* interrupts) needs careful scheduling. Performance improvements can be
* an ongoing challenge. That's in "ehci-sched.c".
*
* USB 1.1 devices are handled (a) by "companion" OHCI or UHCI root hubs,
* or otherwise through transaction translators (TTs) in USB 2.0 hubs using
* (b) special fields in qh entries or (c) split iso entries. TTs will
* buffer low/full speed data so the host collects it at high speed.
*/
/*-------------------------------------------------------------------------*/
/* fill a qtd, returning how much of the buffer we were able to queue up */
static int
qtd_fill(struct ehci_hcd *ehci, struct ehci_qtd *qtd, dma_addr_t buf,
size_t len, int token, int maxpacket)
{
int i, count;
u64 addr = buf;
/* one buffer entry per 4K ... first might be short or unaligned */
qtd->hw_buf[0] = cpu_to_hc32(ehci, (u32)addr);
qtd->hw_buf_hi[0] = cpu_to_hc32(ehci, (u32)(addr >> 32));
count = 0x1000 - (buf & 0x0fff); /* rest of that page */
if (likely (len < count)) /* ... iff needed */
count = len;
else {
buf += 0x1000;
buf &= ~0x0fff;
/* per-qtd limit: from 16K to 20K (best alignment) */
for (i = 1; count < len && i < 5; i++) {
addr = buf;
qtd->hw_buf[i] = cpu_to_hc32(ehci, (u32)addr);
qtd->hw_buf_hi[i] = cpu_to_hc32(ehci,
(u32)(addr >> 32));
buf += 0x1000;
if ((count + 0x1000) < len)
count += 0x1000;
else
count = len;
}
/* short packets may only terminate transfers */
if (count != len)
count -= (count % maxpacket);
}
qtd->hw_token = cpu_to_hc32(ehci, (count << 16) | token);
qtd->length = count;
return count;
}
/*-------------------------------------------------------------------------*/
static inline void
qh_update (struct ehci_hcd *ehci, struct ehci_qh *qh, struct ehci_qtd *qtd)
{
struct ehci_qh_hw *hw = qh->hw;
/* writes to an active overlay are unsafe */
BUG_ON(qh->qh_state != QH_STATE_IDLE);
hw->hw_qtd_next = QTD_NEXT(ehci, qtd->qtd_dma);
hw->hw_alt_next = EHCI_LIST_END(ehci);
/* Except for control endpoints, we make hardware maintain data
* toggle (like OHCI) ... here (re)initialize the toggle in the QH,
* and set the pseudo-toggle in udev. Only usb_clear_halt() will
* ever clear it.
*/
if (!(hw->hw_info1 & cpu_to_hc32(ehci, QH_TOGGLE_CTL))) {
unsigned is_out, epnum;
is_out = qh->is_out;
epnum = (hc32_to_cpup(ehci, &hw->hw_info1) >> 8) & 0x0f;
if (unlikely (!usb_gettoggle (qh->dev, epnum, is_out))) {
hw->hw_token &= ~cpu_to_hc32(ehci, QTD_TOGGLE);
usb_settoggle (qh->dev, epnum, is_out, 1);
}
}
hw->hw_token &= cpu_to_hc32(ehci, QTD_TOGGLE | QTD_STS_PING);
}
/* if it weren't for a common silicon quirk (writing the dummy into the qh
* overlay, so qh->hw_token wrongly becomes inactive/halted), only fault
* recovery (including urb dequeue) would need software changes to a QH...
*/
static void
qh_refresh (struct ehci_hcd *ehci, struct ehci_qh *qh)
{
struct ehci_qtd *qtd;
if (list_empty (&qh->qtd_list))
qtd = qh->dummy;
else {
qtd = list_entry (qh->qtd_list.next,
struct ehci_qtd, qtd_list);
/*
* first qtd may already be partially processed.
* If we come here during unlink, the QH overlay region
* might have reference to the just unlinked qtd. The
* qtd is updated in qh_completions(). Update the QH
* overlay here.
*/
if (cpu_to_hc32(ehci, qtd->qtd_dma) == qh->hw->hw_current) {
qh->hw->hw_qtd_next = qtd->hw_next;
qtd = NULL;
}
}
if (qtd)
qh_update (ehci, qh, qtd);
}
/*-------------------------------------------------------------------------*/
static void qh_link_async(struct ehci_hcd *ehci, struct ehci_qh *qh);
static void ehci_clear_tt_buffer_complete(struct usb_hcd *hcd,
struct usb_host_endpoint *ep)
{
struct ehci_hcd *ehci = hcd_to_ehci(hcd);
struct ehci_qh *qh = ep->hcpriv;
unsigned long flags;
spin_lock_irqsave(&ehci->lock, flags);
qh->clearing_tt = 0;
if (qh->qh_state == QH_STATE_IDLE && !list_empty(&qh->qtd_list)
&& ehci->rh_state == EHCI_RH_RUNNING)
qh_link_async(ehci, qh);
spin_unlock_irqrestore(&ehci->lock, flags);
}
static void ehci_clear_tt_buffer(struct ehci_hcd *ehci, struct ehci_qh *qh,
struct urb *urb, u32 token)
{
/* If an async split transaction gets an error or is unlinked,
* the TT buffer may be left in an indeterminate state. We
* have to clear the TT buffer.
*
* Note: this routine is never called for Isochronous transfers.
*/
if (urb->dev->tt && !usb_pipeint(urb->pipe) && !qh->clearing_tt) {
#ifdef DEBUG
struct usb_device *tt = urb->dev->tt->hub;
dev_dbg(&tt->dev,
"clear tt buffer port %d, a%d ep%d t%08x\n",
urb->dev->ttport, urb->dev->devnum,
usb_pipeendpoint(urb->pipe), token);
#endif /* DEBUG */
if (!ehci_is_TDI(ehci)
|| urb->dev->tt->hub !=
ehci_to_hcd(ehci)->self.root_hub) {
if (usb_hub_clear_tt_buffer(urb) == 0)
qh->clearing_tt = 1;
} else {
/* REVISIT ARC-derived cores don't clear the root
* hub TT buffer in this way...
*/
}
}
}
static int qtd_copy_status (
struct ehci_hcd *ehci,
struct urb *urb,
size_t length,
u32 token
)
{
int status = -EINPROGRESS;
/* count IN/OUT bytes, not SETUP (even short packets) */
if (likely (QTD_PID (token) != 2))
urb->actual_length += length - QTD_LENGTH (token);
/* don't modify error codes */
if (unlikely(urb->unlinked))
return status;
/* force cleanup after short read; not always an error */
if (unlikely (IS_SHORT_READ (token)))
status = -EREMOTEIO;
/* serious "can't proceed" faults reported by the hardware */
if (token & QTD_STS_HALT) {
if (token & QTD_STS_BABBLE) {
/* FIXME "must" disable babbling device's port too */
status = -EOVERFLOW;
/* CERR nonzero + halt --> stall */
} else if (QTD_CERR(token)) {
status = -EPIPE;
/* In theory, more than one of the following bits can be set
* since they are sticky and the transaction is retried.
* Which to test first is rather arbitrary.
*/
} else if (token & QTD_STS_MMF) {
/* fs/ls interrupt xfer missed the complete-split */
status = -EPROTO;
} else if (token & QTD_STS_DBE) {
status = (QTD_PID (token) == 1) /* IN ? */
? -ENOSR /* hc couldn't read data */
: -ECOMM; /* hc couldn't write data */
} else if (token & QTD_STS_XACT) {
/* timeout, bad CRC, wrong PID, etc */
ehci_dbg(ehci, "devpath %s ep%d%s 3strikes\n",
urb->dev->devpath,
usb_pipeendpoint(urb->pipe),
usb_pipein(urb->pipe) ? "in" : "out");
status = -EPROTO;
} else { /* unknown */
status = -EPROTO;
}
ehci_vdbg (ehci,
"dev%d ep%d%s qtd token %08x --> status %d\n",
usb_pipedevice (urb->pipe),
usb_pipeendpoint (urb->pipe),
usb_pipein (urb->pipe) ? "in" : "out",
token, status);
}
return status;
}
static void
ehci_urb_done(struct ehci_hcd *ehci, struct urb *urb, int status)
__releases(ehci->lock)
__acquires(ehci->lock)
{
if (usb_pipetype(urb->pipe) == PIPE_INTERRUPT) {
/* ... update hc-wide periodic stats */
ehci_to_hcd(ehci)->self.bandwidth_int_reqs--;
}
if (unlikely(urb->unlinked)) {
COUNT(ehci->stats.unlink);
} else {
/* report non-error and short read status as zero */
if (status == -EINPROGRESS || status == -EREMOTEIO)
status = 0;
COUNT(ehci->stats.complete);
}
#ifdef EHCI_URB_TRACE
ehci_dbg (ehci,
"%s %s urb %p ep%d%s status %d len %d/%d\n",
__func__, urb->dev->devpath, urb,
usb_pipeendpoint (urb->pipe),
usb_pipein (urb->pipe) ? "in" : "out",
status,
urb->actual_length, urb->transfer_buffer_length);
#endif
/* complete() can reenter this HCD */
usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
spin_unlock (&ehci->lock);
usb_hcd_giveback_urb(ehci_to_hcd(ehci), urb, status);
spin_lock (&ehci->lock);
}
static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh);
/*
* Process and free completed qtds for a qh, returning URBs to drivers.
* Chases up to qh->hw_current. Returns number of completions called,
* indicating how much "real" work we did.
*/
static unsigned
qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
{
struct ehci_qtd *last, *end = qh->dummy;
struct list_head *entry, *tmp;
int last_status;
int stopped;
unsigned count = 0;
u8 state;
struct ehci_qh_hw *hw = qh->hw;
if (unlikely (list_empty (&qh->qtd_list)))
return count;
/* completions (or tasks on other cpus) must never clobber HALT
* till we've gone through and cleaned everything up, even when
* they add urbs to this qh's queue or mark them for unlinking.
*
* NOTE: unlinking expects to be done in queue order.
*
* It's a bug for qh->qh_state to be anything other than
* QH_STATE_IDLE, unless our caller is scan_async() or
* scan_intr().
*/
state = qh->qh_state;
qh->qh_state = QH_STATE_COMPLETING;
stopped = (state == QH_STATE_IDLE);
rescan:
last = NULL;
last_status = -EINPROGRESS;
qh->needs_rescan = 0;
/* remove de-activated QTDs from front of queue.
* after faults (including short reads), cleanup this urb
* then let the queue advance.
* if queue is stopped, handles unlinks.
*/
list_for_each_safe (entry, tmp, &qh->qtd_list) {
struct ehci_qtd *qtd;
struct urb *urb;
u32 token = 0;
qtd = list_entry (entry, struct ehci_qtd, qtd_list);
urb = qtd->urb;
/* clean up any state from previous QTD ...*/
if (last) {
if (likely (last->urb != urb)) {
ehci_urb_done(ehci, last->urb, last_status);
count++;
last_status = -EINPROGRESS;
}
ehci_qtd_free (ehci, last);
last = NULL;
}
/* ignore urbs submitted during completions we reported */
if (qtd == end)
break;
/* hardware copies qtd out of qh overlay */
rmb ();
token = hc32_to_cpu(ehci, qtd->hw_token);
/* always clean up qtds the hc de-activated */
retry_xacterr:
if ((token & QTD_STS_ACTIVE) == 0) {
/* Report Data Buffer Error: non-fatal but useful */
if (token & QTD_STS_DBE)
ehci_dbg(ehci,
"detected DataBufferErr for urb %p ep%d%s len %d, qtd %p [qh %p]\n",
urb,
usb_endpoint_num(&urb->ep->desc),
usb_endpoint_dir_in(&urb->ep->desc) ? "in" : "out",
urb->transfer_buffer_length,
qtd,
qh);
/* on STALL, error, and short reads this urb must
* complete and all its qtds must be recycled.
*/
if ((token & QTD_STS_HALT) != 0) {
/* retry transaction errors until we
* reach the software xacterr limit
*/
if ((token & QTD_STS_XACT) &&
QTD_CERR(token) == 0 &&
++qh->xacterrs < QH_XACTERR_MAX &&
!urb->unlinked) {
ehci_dbg(ehci,
"detected XactErr len %zu/%zu retry %d\n",
qtd->length - QTD_LENGTH(token), qtd->length, qh->xacterrs);
/* reset the token in the qtd and the
* qh overlay (which still contains
* the qtd) so that we pick up from
* where we left off
*/
token &= ~QTD_STS_HALT;
token |= QTD_STS_ACTIVE |
(EHCI_TUNE_CERR << 10);
qtd->hw_token = cpu_to_hc32(ehci,
token);
wmb();
hw->hw_token = cpu_to_hc32(ehci,
token);
goto retry_xacterr;
}
stopped = 1;
/* magic dummy for some short reads; qh won't advance.
* that silicon quirk can kick in with this dummy too.
*
* other short reads won't stop the queue, including
* control transfers (status stage handles that) or
* most other single-qtd reads ... the queue stops if
* URB_SHORT_NOT_OK was set so the driver submitting
* the urbs could clean it up.
*/
} else if (IS_SHORT_READ (token)
&& !(qtd->hw_alt_next
& EHCI_LIST_END(ehci))) {
stopped = 1;
}
/* stop scanning when we reach qtds the hc is using */
} else if (likely (!stopped
&& ehci->rh_state >= EHCI_RH_RUNNING)) {
break;
/* scan the whole queue for unlinks whenever it stops */
} else {
stopped = 1;
/* cancel everything if we halt, suspend, etc */
if (ehci->rh_state < EHCI_RH_RUNNING)
last_status = -ESHUTDOWN;
/* this qtd is active; skip it unless a previous qtd
* for its urb faulted, or its urb was canceled.
*/
else if (last_status == -EINPROGRESS && !urb->unlinked)
continue;
/* qh unlinked; token in overlay may be most current */
if (state == QH_STATE_IDLE
&& cpu_to_hc32(ehci, qtd->qtd_dma)
== hw->hw_current) {
token = hc32_to_cpu(ehci, hw->hw_token);
/* An unlink may leave an incomplete
* async transaction in the TT buffer.
* We have to clear it.
*/
ehci_clear_tt_buffer(ehci, qh, urb, token);
}
}
/* unless we already know the urb's status, collect qtd status
* and update count of bytes transferred. in common short read
* cases with only one data qtd (including control transfers),
* queue processing won't halt. but with two or more qtds (for
* example, with a 32 KB transfer), when the first qtd gets a
* short read the second must be removed by hand.
*/
if (last_status == -EINPROGRESS) {
last_status = qtd_copy_status(ehci, urb,
qtd->length, token);
if (last_status == -EREMOTEIO
&& (qtd->hw_alt_next
& EHCI_LIST_END(ehci)))
last_status = -EINPROGRESS;
/* As part of low/full-speed endpoint-halt processing
* we must clear the TT buffer (11.17.5).
*/
if (unlikely(last_status != -EINPROGRESS &&
last_status != -EREMOTEIO)) {
/* The TT's in some hubs malfunction when they
* receive this request following a STALL (they
* stop sending isochronous packets). Since a
* STALL can't leave the TT buffer in a busy
* state (if you believe Figures 11-48 - 11-51
* in the USB 2.0 spec), we won't clear the TT
* buffer in this case. Strictly speaking this
* is a violation of the spec.
*/
if (last_status != -EPIPE)
ehci_clear_tt_buffer(ehci, qh, urb,
token);
}
}
/* if we're removing something not at the queue head,
* patch the hardware queue pointer.
*/
if (stopped && qtd->qtd_list.prev != &qh->qtd_list) {
last = list_entry (qtd->qtd_list.prev,
struct ehci_qtd, qtd_list);
last->hw_next = qtd->hw_next;
}
/* remove qtd; it's recycled after possible urb completion */
list_del (&qtd->qtd_list);
last = qtd;
/* reinit the xacterr counter for the next qtd */
qh->xacterrs = 0;
}
/* last urb's completion might still need calling */
if (likely (last != NULL)) {
ehci_urb_done(ehci, last->urb, last_status);
count++;
ehci_qtd_free (ehci, last);
}
/* Do we need to rescan for URBs dequeued during a giveback? */
if (unlikely(qh->needs_rescan)) {
/* If the QH is already unlinked, do the rescan now. */
if (state == QH_STATE_IDLE)
goto rescan;
/* Otherwise we have to wait until the QH is fully unlinked.
* Our caller will start an unlink if qh->needs_rescan is
* set. But if an unlink has already started, nothing needs
* to be done.
*/
if (state != QH_STATE_LINKED)
qh->needs_rescan = 0;
}
/* restore original state; caller must unlink or relink */
qh->qh_state = state;
/* be sure the hardware's done with the qh before refreshing
* it after fault cleanup, or recovering from silicon wrongly
* overlaying the dummy qtd (which reduces DMA chatter).
*/
if (stopped != 0 || hw->hw_qtd_next == EHCI_LIST_END(ehci)) {
switch (state) {
case QH_STATE_IDLE:
qh_refresh(ehci, qh);
break;
case QH_STATE_LINKED:
/* We won't refresh a QH that's linked (after the HC
* stopped the queue). That avoids a race:
* - HC reads first part of QH;
* - CPU updates that first part and the token;
* - HC reads rest of that QH, including token
* Result: HC gets an inconsistent image, and then
* DMAs to/from the wrong memory (corrupting it).
*
* That should be rare for interrupt transfers,
* except maybe high bandwidth ...
*/
/* Tell the caller to start an unlink */
qh->needs_rescan = 1;
break;
/* otherwise, unlink already started */
}
}
return count;
}
/*-------------------------------------------------------------------------*/
// high bandwidth multiplier, as encoded in highspeed endpoint descriptors
#define hb_mult(wMaxPacketSize) (1 + (((wMaxPacketSize) >> 11) & 0x03))
// ... and packet size, for any kind of endpoint descriptor
#define max_packet(wMaxPacketSize) ((wMaxPacketSize) & 0x07ff)
/*
* reverse of qh_urb_transaction: free a list of TDs.
* used for cleanup after errors, before HC sees an URB's TDs.
*/
static void qtd_list_free (
struct ehci_hcd *ehci,
struct urb *urb,
struct list_head *qtd_list
) {
struct list_head *entry, *temp;
list_for_each_safe (entry, temp, qtd_list) {
struct ehci_qtd *qtd;
qtd = list_entry (entry, struct ehci_qtd, qtd_list);
list_del (&qtd->qtd_list);
ehci_qtd_free (ehci, qtd);
}
}
/*
* create a list of filled qtds for this URB; won't link into qh.
*/
static struct list_head *
qh_urb_transaction (
struct ehci_hcd *ehci,
struct urb *urb,
struct list_head *head,
gfp_t flags
) {
struct ehci_qtd *qtd, *qtd_prev;
dma_addr_t buf;
int len, this_sg_len, maxpacket;
int is_input;
u32 token;
int i;
struct scatterlist *sg;
/*
* URBs map to sequences of QTDs: one logical transaction
*/
qtd = ehci_qtd_alloc (ehci, flags);
if (unlikely (!qtd))
return NULL;
list_add_tail (&qtd->qtd_list, head);
qtd->urb = urb;
token = QTD_STS_ACTIVE;
token |= (EHCI_TUNE_CERR << 10);
/* for split transactions, SplitXState initialized to zero */
len = urb->transfer_buffer_length;
is_input = usb_pipein (urb->pipe);
if (usb_pipecontrol (urb->pipe)) {
/* SETUP pid */
qtd_fill(ehci, qtd, urb->setup_dma,
sizeof (struct usb_ctrlrequest),
token | (2 /* "setup" */ << 8), 8);
/* ... and always at least one more pid */
token ^= QTD_TOGGLE;
qtd_prev = qtd;
qtd = ehci_qtd_alloc (ehci, flags);
if (unlikely (!qtd))
goto cleanup;
qtd->urb = urb;
qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
list_add_tail (&qtd->qtd_list, head);
/* for zero length DATA stages, STATUS is always IN */
if (len == 0)
token |= (1 /* "in" */ << 8);
}
/*
* data transfer stage: buffer setup
*/
i = urb->num_mapped_sgs;
if (len > 0 && i > 0) {
sg = urb->sg;
buf = sg_dma_address(sg);
/* urb->transfer_buffer_length may be smaller than the
* size of the scatterlist (or vice versa)
*/
this_sg_len = min_t(int, sg_dma_len(sg), len);
} else {
sg = NULL;
buf = urb->transfer_dma;
this_sg_len = len;
}
if (is_input)
token |= (1 /* "in" */ << 8);
/* else it's already initted to "out" pid (0 << 8) */
maxpacket = max_packet(usb_maxpacket(urb->dev, urb->pipe, !is_input));
/*
* buffer gets wrapped in one or more qtds;
* last one may be "short" (including zero len)
* and may serve as a control status ack
*/
for (;;) {
int this_qtd_len;
this_qtd_len = qtd_fill(ehci, qtd, buf, this_sg_len, token,
maxpacket);
this_sg_len -= this_qtd_len;
len -= this_qtd_len;
buf += this_qtd_len;
/*
* short reads advance to a "magic" dummy instead of the next
* qtd ... that forces the queue to stop, for manual cleanup.
* (this will usually be overridden later.)
*/
if (is_input)
qtd->hw_alt_next = ehci->async->hw->hw_alt_next;
/* qh makes control packets use qtd toggle; maybe switch it */
if ((maxpacket & (this_qtd_len + (maxpacket - 1))) == 0)
token ^= QTD_TOGGLE;
if (likely(this_sg_len <= 0)) {
if (--i <= 0 || len <= 0)
break;
sg = sg_next(sg);
buf = sg_dma_address(sg);
this_sg_len = min_t(int, sg_dma_len(sg), len);
}
qtd_prev = qtd;
qtd = ehci_qtd_alloc (ehci, flags);
if (unlikely (!qtd))
goto cleanup;
qtd->urb = urb;
qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
list_add_tail (&qtd->qtd_list, head);
}
/*
* unless the caller requires manual cleanup after short reads,
* have the alt_next mechanism keep the queue running after the
* last data qtd (the only one, for control and most other cases).
*/
if (likely ((urb->transfer_flags & URB_SHORT_NOT_OK) == 0
|| usb_pipecontrol (urb->pipe)))
qtd->hw_alt_next = EHCI_LIST_END(ehci);
/*
* control requests may need a terminating data "status" ack;
* other OUT ones may need a terminating short packet
* (zero length).
*/
if (likely (urb->transfer_buffer_length != 0)) {
int one_more = 0;
if (usb_pipecontrol (urb->pipe)) {
one_more = 1;
token ^= 0x0100; /* "in" <--> "out" */
token |= QTD_TOGGLE; /* force DATA1 */
} else if (usb_pipeout(urb->pipe)
&& (urb->transfer_flags & URB_ZERO_PACKET)
&& !(urb->transfer_buffer_length % maxpacket)) {
one_more = 1;
}
if (one_more) {
qtd_prev = qtd;
qtd = ehci_qtd_alloc (ehci, flags);
if (unlikely (!qtd))
goto cleanup;
qtd->urb = urb;
qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
list_add_tail (&qtd->qtd_list, head);
/* never any data in such packets */
qtd_fill(ehci, qtd, 0, 0, token, 0);
}
}
/* by default, enable interrupt on urb completion */
if (likely (!(urb->transfer_flags & URB_NO_INTERRUPT)))
qtd->hw_token |= cpu_to_hc32(ehci, QTD_IOC);
return head;
cleanup:
qtd_list_free (ehci, urb, head);
return NULL;
}
/*-------------------------------------------------------------------------*/
// Would be best to create all qh's from config descriptors,
// when each interface/altsetting is established. Unlink
// any previous qh and cancel its urbs first; endpoints are
// implicitly reset then (data toggle too).
// That'd mean updating how usbcore talks to HCDs. (2.7?)
/*
* Each QH holds a qtd list; a QH is used for everything except iso.
*
* For interrupt urbs, the scheduler must set the microframe scheduling
* mask(s) each time the QH gets scheduled. For highspeed, that's
* just one microframe in the s-mask. For split interrupt transactions
* there are additional complications: c-mask, maybe FSTNs.
*/
static struct ehci_qh *
qh_make (
struct ehci_hcd *ehci,
struct urb *urb,
gfp_t flags
) {
struct ehci_qh *qh = ehci_qh_alloc (ehci, flags);
u32 info1 = 0, info2 = 0;
int is_input, type;
int maxp = 0;
struct usb_tt *tt = urb->dev->tt;
struct ehci_qh_hw *hw;
if (!qh)
return qh;
/*
* init endpoint/device data for this QH
*/
info1 |= usb_pipeendpoint (urb->pipe) << 8;
info1 |= usb_pipedevice (urb->pipe) << 0;
is_input = usb_pipein (urb->pipe);
type = usb_pipetype (urb->pipe);
maxp = usb_maxpacket (urb->dev, urb->pipe, !is_input);
/* 1024 byte maxpacket is a hardware ceiling. High bandwidth
* acts like up to 3KB, but is built from smaller packets.
*/
if (max_packet(maxp) > 1024) {
ehci_dbg(ehci, "bogus qh maxpacket %d\n", max_packet(maxp));
goto done;
}
/* Compute interrupt scheduling parameters just once, and save.
* - allowing for high bandwidth, how many nsec/uframe are used?
* - split transactions need a second CSPLIT uframe; same question
* - splits also need a schedule gap (for full/low speed I/O)
* - qh has a polling interval
*
* For control/bulk requests, the HC or TT handles these.
*/
if (type == PIPE_INTERRUPT) {
qh->usecs = NS_TO_US(usb_calc_bus_time(USB_SPEED_HIGH,
is_input, 0,
hb_mult(maxp) * max_packet(maxp)));
qh->start = NO_FRAME;
if (urb->dev->speed == USB_SPEED_HIGH) {
qh->c_usecs = 0;
qh->gap_uf = 0;
qh->period = urb->interval >> 3;
if (qh->period == 0 && urb->interval != 1) {
/* NOTE interval 2 or 4 uframes could work.
* But interval 1 scheduling is simpler, and
* includes high bandwidth.
*/
urb->interval = 1;
} else if (qh->period > ehci->periodic_size) {
qh->period = ehci->periodic_size;
urb->interval = qh->period << 3;
}
} else {
int think_time;
/* gap is f(FS/LS transfer times) */
qh->gap_uf = 1 + usb_calc_bus_time (urb->dev->speed,
is_input, 0, maxp) / (125 * 1000);
/* FIXME this just approximates SPLIT/CSPLIT times */
if (is_input) { // SPLIT, gap, CSPLIT+DATA
qh->c_usecs = qh->usecs + HS_USECS (0);
qh->usecs = HS_USECS (1);
} else { // SPLIT+DATA, gap, CSPLIT
qh->usecs += HS_USECS (1);
qh->c_usecs = HS_USECS (0);
}
think_time = tt ? tt->think_time : 0;
qh->tt_usecs = NS_TO_US (think_time +
usb_calc_bus_time (urb->dev->speed,
is_input, 0, max_packet (maxp)));
qh->period = urb->interval;
if (qh->period > ehci->periodic_size) {
qh->period = ehci->periodic_size;
urb->interval = qh->period;
}
}
}
/* support for tt scheduling, and access to toggles */
qh->dev = urb->dev;
/* using TT? */
switch (urb->dev->speed) {
case USB_SPEED_LOW:
info1 |= QH_LOW_SPEED;
/* FALL THROUGH */
case USB_SPEED_FULL:
/* EPS 0 means "full" */
if (type != PIPE_INTERRUPT)
info1 |= (EHCI_TUNE_RL_TT << 28);
if (type == PIPE_CONTROL) {
info1 |= QH_CONTROL_EP; /* for TT */
info1 |= QH_TOGGLE_CTL; /* toggle from qtd */
}
info1 |= maxp << 16;
info2 |= (EHCI_TUNE_MULT_TT << 30);
/* Some Freescale processors have an erratum in which the
* port number in the queue head was 0..N-1 instead of 1..N.
*/
if (ehci_has_fsl_portno_bug(ehci))
info2 |= (urb->dev->ttport-1) << 23;
else
info2 |= urb->dev->ttport << 23;
/* set the address of the TT; for TDI's integrated
* root hub tt, leave it zeroed.
*/
if (tt && tt->hub != ehci_to_hcd(ehci)->self.root_hub)
info2 |= tt->hub->devnum << 16;
/* NOTE: if (PIPE_INTERRUPT) { scheduler sets c-mask } */
break;
case USB_SPEED_HIGH: /* no TT involved */
info1 |= QH_HIGH_SPEED;
if (type == PIPE_CONTROL) {
info1 |= (EHCI_TUNE_RL_HS << 28);
info1 |= 64 << 16; /* usb2 fixed maxpacket */
info1 |= QH_TOGGLE_CTL; /* toggle from qtd */
info2 |= (EHCI_TUNE_MULT_HS << 30);
} else if (type == PIPE_BULK) {
info1 |= (EHCI_TUNE_RL_HS << 28);
/* The USB spec says that high speed bulk endpoints
* always use 512 byte maxpacket. But some device
* vendors decided to ignore that, and MSFT is happy
* to help them do so. So now people expect to use
* such nonconformant devices with Linux too; sigh.
*/
info1 |= max_packet(maxp) << 16;
info2 |= (EHCI_TUNE_MULT_HS << 30);
} else { /* PIPE_INTERRUPT */
info1 |= max_packet (maxp) << 16;
info2 |= hb_mult (maxp) << 30;
}
break;
default:
ehci_dbg(ehci, "bogus dev %p speed %d\n", urb->dev,
urb->dev->speed);
done:
qh_destroy(ehci, qh);
return NULL;
}
/* NOTE: if (PIPE_INTERRUPT) { scheduler sets s-mask } */
/* init as live, toggle clear, advance to dummy */
qh->qh_state = QH_STATE_IDLE;
hw = qh->hw;
hw->hw_info1 = cpu_to_hc32(ehci, info1);
hw->hw_info2 = cpu_to_hc32(ehci, info2);
qh->is_out = !is_input;
usb_settoggle (urb->dev, usb_pipeendpoint (urb->pipe), !is_input, 1);
qh_refresh (ehci, qh);
return qh;
}
/*-------------------------------------------------------------------------*/
static void enable_async(struct ehci_hcd *ehci)
{
if (ehci->async_count++)
return;
/* Stop waiting to turn off the async schedule */
ehci->enabled_hrtimer_events &= ~BIT(EHCI_HRTIMER_DISABLE_ASYNC);
/* Don't start the schedule until ASS is 0 */
ehci_poll_ASS(ehci);
turn_on_io_watchdog(ehci);
}
static void disable_async(struct ehci_hcd *ehci)
{
if (--ehci->async_count)
return;
/* The async schedule and async_unlink list are supposed to be empty */
WARN_ON(ehci->async->qh_next.qh || ehci->async_unlink);
/* Don't turn off the schedule until ASS is 1 */
ehci_poll_ASS(ehci);
}
/* move qh (and its qtds) onto async queue; maybe enable queue. */
static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
{
__hc32 dma = QH_NEXT(ehci, qh->qh_dma);
struct ehci_qh *head;
/* Don't link a QH if there's a Clear-TT-Buffer pending */
if (unlikely(qh->clearing_tt))
return;
WARN_ON(qh->qh_state != QH_STATE_IDLE);
/* clear halt and/or toggle; and maybe recover from silicon quirk */
qh_refresh(ehci, qh);
/* splice right after start */
head = ehci->async;
qh->qh_next = head->qh_next;
qh->hw->hw_next = head->hw->hw_next;
wmb ();
head->qh_next.qh = qh;
head->hw->hw_next = dma;
qh->xacterrs = 0;
qh->qh_state = QH_STATE_LINKED;
/* qtd completions reported later by interrupt */
enable_async(ehci);
}
/*-------------------------------------------------------------------------*/
/*
* For control/bulk/interrupt, return QH with these TDs appended.
* Allocates and initializes the QH if necessary.
* Returns null if it can't allocate a QH it needs to.
* If the QH has TDs (urbs) already, that's great.
*/
static struct ehci_qh *qh_append_tds (
struct ehci_hcd *ehci,
struct urb *urb,
struct list_head *qtd_list,
int epnum,
void **ptr
)
{
struct ehci_qh *qh = NULL;
__hc32 qh_addr_mask = cpu_to_hc32(ehci, 0x7f);
qh = (struct ehci_qh *) *ptr;
if (unlikely (qh == NULL)) {
/* can't sleep here, we have ehci->lock... */
qh = qh_make (ehci, urb, GFP_ATOMIC);
*ptr = qh;
}
if (likely (qh != NULL)) {
struct ehci_qtd *qtd;
if (unlikely (list_empty (qtd_list)))
qtd = NULL;
else
qtd = list_entry (qtd_list->next, struct ehci_qtd,
qtd_list);
/* control qh may need patching ... */
if (unlikely (epnum == 0)) {
/* usb_reset_device() briefly reverts to address 0 */
if (usb_pipedevice (urb->pipe) == 0)
qh->hw->hw_info1 &= ~qh_addr_mask;
}
/* just one way to queue requests: swap with the dummy qtd.
* only hc or qh_refresh() ever modify the overlay.
*/
if (likely (qtd != NULL)) {
struct ehci_qtd *dummy;
dma_addr_t dma;
__hc32 token;
/* to avoid racing the HC, use the dummy td instead of
* the first td of our list (becomes new dummy). both
* tds stay deactivated until we're done, when the
* HC is allowed to fetch the old dummy (4.10.2).
*/
token = qtd->hw_token;
qtd->hw_token = HALT_BIT(ehci);
dummy = qh->dummy;
dma = dummy->qtd_dma;
*dummy = *qtd;
dummy->qtd_dma = dma;
list_del (&qtd->qtd_list);
list_add (&dummy->qtd_list, qtd_list);
list_splice_tail(qtd_list, &qh->qtd_list);
ehci_qtd_init(ehci, qtd, qtd->qtd_dma);
qh->dummy = qtd;
/* hc must see the new dummy at list end */
dma = qtd->qtd_dma;
qtd = list_entry (qh->qtd_list.prev,
struct ehci_qtd, qtd_list);
qtd->hw_next = QTD_NEXT(ehci, dma);
/* let the hc process these next qtds */
wmb ();
dummy->hw_token = token;
urb->hcpriv = qh;
}
}
return qh;
}
/*-------------------------------------------------------------------------*/
static int
submit_async (
struct ehci_hcd *ehci,
struct urb *urb,
struct list_head *qtd_list,
gfp_t mem_flags
) {
int epnum;
unsigned long flags;
struct ehci_qh *qh = NULL;
int rc;
epnum = urb->ep->desc.bEndpointAddress;
#ifdef EHCI_URB_TRACE
{
struct ehci_qtd *qtd;
qtd = list_entry(qtd_list->next, struct ehci_qtd, qtd_list);
ehci_dbg(ehci,
"%s %s urb %p ep%d%s len %d, qtd %p [qh %p]\n",
__func__, urb->dev->devpath, urb,
epnum & 0x0f, (epnum & USB_DIR_IN) ? "in" : "out",
urb->transfer_buffer_length,
qtd, urb->ep->hcpriv);
}
#endif
spin_lock_irqsave (&ehci->lock, flags);
if (unlikely(!HCD_HW_ACCESSIBLE(ehci_to_hcd(ehci)))) {
rc = -ESHUTDOWN;
goto done;
}
rc = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
if (unlikely(rc))
goto done;
qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
if (unlikely(qh == NULL)) {
usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
rc = -ENOMEM;
goto done;
}
/* Control/bulk operations through TTs don't need scheduling,
* the HC and TT handle it when the TT has a buffer ready.
*/
if (likely (qh->qh_state == QH_STATE_IDLE))
qh_link_async(ehci, qh);
done:
spin_unlock_irqrestore (&ehci->lock, flags);
if (unlikely (qh == NULL))
qtd_list_free (ehci, urb, qtd_list);
return rc;
}
/*-------------------------------------------------------------------------*/
static void single_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh)
{
struct ehci_qh *prev;
/* Add to the end of the list of QHs waiting for the next IAAD */
qh->qh_state = QH_STATE_UNLINK;
if (ehci->async_unlink)
ehci->async_unlink_last->unlink_next = qh;
else
ehci->async_unlink = qh;
ehci->async_unlink_last = qh;
/* Unlink it from the schedule */
prev = ehci->async;
while (prev->qh_next.qh != qh)
prev = prev->qh_next.qh;
prev->hw->hw_next = qh->hw->hw_next;
prev->qh_next = qh->qh_next;
if (ehci->qh_scan_next == qh)
ehci->qh_scan_next = qh->qh_next.qh;
}
static void start_iaa_cycle(struct ehci_hcd *ehci, bool nested)
{
/*
* Do nothing if an IAA cycle is already running or
* if one will be started shortly.
*/
if (ehci->async_iaa || ehci->async_unlinking)
return;
/* If the controller isn't running, we don't have to wait for it */
if (unlikely(ehci->rh_state < EHCI_RH_RUNNING)) {
/* Do all the waiting QHs */
ehci->async_iaa = ehci->async_unlink;
ehci->async_unlink = NULL;
if (!nested) /* Avoid recursion */
end_unlink_async(ehci);
/* Otherwise start a new IAA cycle */
} else if (likely(ehci->rh_state == EHCI_RH_RUNNING)) {
struct ehci_qh *qh;
/* Do only the first waiting QH (nVidia bug?) */
qh = ehci->async_unlink;
ehci->async_iaa = qh;
ehci->async_unlink = qh->unlink_next;
qh->unlink_next = NULL;
/* Make sure the unlinks are all visible to the hardware */
wmb();
ehci_writel(ehci, ehci->command | CMD_IAAD,
&ehci->regs->command);
ehci_readl(ehci, &ehci->regs->command);
ehci_enable_event(ehci, EHCI_HRTIMER_IAA_WATCHDOG, true);
}
}
/* the async qh for the qtds being unlinked are now gone from the HC */
static void end_unlink_async(struct ehci_hcd *ehci)
{
struct ehci_qh *qh;
if (ehci->has_synopsys_hc_bug)
ehci_writel(ehci, (u32) ehci->async->qh_dma,
&ehci->regs->async_next);
/* Process the idle QHs */
restart:
ehci->async_unlinking = true;
while (ehci->async_iaa) {
qh = ehci->async_iaa;
ehci->async_iaa = qh->unlink_next;
qh->unlink_next = NULL;
qh->qh_state = QH_STATE_IDLE;
qh->qh_next.qh = NULL;
qh_completions(ehci, qh);
if (!list_empty(&qh->qtd_list) &&
ehci->rh_state == EHCI_RH_RUNNING)
qh_link_async(ehci, qh);
disable_async(ehci);
}
ehci->async_unlinking = false;
/* Start a new IAA cycle if any QHs are waiting for it */
if (ehci->async_unlink) {
start_iaa_cycle(ehci, true);
if (unlikely(ehci->rh_state < EHCI_RH_RUNNING))
goto restart;
}
}
static void start_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh);
static void unlink_empty_async(struct ehci_hcd *ehci)
{
struct ehci_qh *qh;
struct ehci_qh *qh_to_unlink = NULL;
bool check_unlinks_later = false;
int count = 0;
/* Find the last async QH which has been empty for a timer cycle */
for (qh = ehci->async->qh_next.qh; qh; qh = qh->qh_next.qh) {
if (list_empty(&qh->qtd_list) &&
qh->qh_state == QH_STATE_LINKED) {
++count;
if (qh->unlink_cycle == ehci->async_unlink_cycle)
check_unlinks_later = true;
else
qh_to_unlink = qh;
}
}
/* If nothing else is being unlinked, unlink the last empty QH */
if (!ehci->async_iaa && !ehci->async_unlink && qh_to_unlink) {
start_unlink_async(ehci, qh_to_unlink);
--count;
}
/* Other QHs will be handled later */
if (count > 0) {
ehci_enable_event(ehci, EHCI_HRTIMER_ASYNC_UNLINKS, true);
++ehci->async_unlink_cycle;
}
}
/* makes sure the async qh will become idle */
/* caller must own ehci->lock */
static void start_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh)
{
/*
* 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;
}
single_unlink_async(ehci, qh);
start_iaa_cycle(ehci, false);
}
/*-------------------------------------------------------------------------*/
static void scan_async (struct ehci_hcd *ehci)
{
struct ehci_qh *qh;
bool check_unlinks_later = false;
ehci->qh_scan_next = ehci->async->qh_next.qh;
while (ehci->qh_scan_next) {
qh = ehci->qh_scan_next;
ehci->qh_scan_next = qh->qh_next.qh;
rescan:
/* clean any finished work for this qh */
if (!list_empty(&qh->qtd_list)) {
int temp;
/*
* Unlinks could happen here; completion reporting
* drops the lock. That's why ehci->qh_scan_next
* always holds the next qh to scan; if the next qh
* gets unlinked then ehci->qh_scan_next is adjusted
* in single_unlink_async().
*/
temp = qh_completions(ehci, qh);
if (qh->needs_rescan) {
start_unlink_async(ehci, qh);
} else if (list_empty(&qh->qtd_list)
&& qh->qh_state == QH_STATE_LINKED) {
qh->unlink_cycle = ehci->async_unlink_cycle;
check_unlinks_later = true;
} else if (temp != 0)
goto rescan;
}
}
/*
* Unlink empty entries, reducing DMA usage as well
* as HCD schedule-scanning costs. Delay for any qh
* we just scanned, there's a not-unusual case that it
* doesn't stay idle for long.
*/
if (check_unlinks_later && ehci->rh_state == EHCI_RH_RUNNING &&
!(ehci->enabled_hrtimer_events &
BIT(EHCI_HRTIMER_ASYNC_UNLINKS))) {
ehci_enable_event(ehci, EHCI_HRTIMER_ASYNC_UNLINKS, true);
++ehci->async_unlink_cycle;
}
}
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