--- /dev/null
+/*
+ * 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 */
+ WARN_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->ps.udev, epnum, is_out))) {
+ hw->hw_token &= ~cpu_to_hc32(ehci, QTD_TOGGLE);
+ usb_settoggle(qh->ps.udev, 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;
+
+ 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 (qh->hw->hw_token & ACTIVE_BIT(ehci))
+ qh->hw->hw_qtd_next = qtd->hw_next;
+ else
+ 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 CONFIG_DYNAMIC_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 /* CONFIG_DYNAMIC_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;
+ }
+ }
+
+ return status;
+}
+
+static void
+ehci_urb_done(struct ehci_hcd *ehci, struct urb *urb, int status)
+{
+ 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
+
+ usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
+ usb_hcd_giveback_urb(ehci_to_hcd(ehci), urb, status);
+}
+
+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 nonzero if the caller should
+ * unlink qh.
+ */
+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;
+ u8 state;
+ struct ehci_qh_hw *hw = qh->hw;
+
+ /* 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->dequeue_during_giveback = 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);
+ 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;
+
+ /*
+ * If this was the active qtd when the qh was unlinked
+ * and the overlay's token is active, then the overlay
+ * hasn't been written back to the qtd yet so use its
+ * token instead of the qtd's. After the qtd is
+ * processed and removed, the overlay won't be valid
+ * any more.
+ */
+ if (state == QH_STATE_IDLE &&
+ qh->qtd_list.next == &qtd->qtd_list &&
+ (hw->hw_token & ACTIVE_BIT(ehci))) {
+ token = hc32_to_cpu(ehci, hw->hw_token);
+ hw->hw_token &= ~ACTIVE_BIT(ehci);
+
+ /* 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);
+ ehci_qtd_free (ehci, last);
+ }
+
+ /* Do we need to rescan for URBs dequeued during a giveback? */
+ if (unlikely(qh->dequeue_during_giveback)) {
+ /* If the QH is already unlinked, do the rescan now. */
+ if (state == QH_STATE_IDLE)
+ goto rescan;
+
+ /* Otherwise the caller must unlink the QH. */
+ }
+
+ /* 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).
+ *
+ * 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 ...
+ */
+ if (stopped != 0 || hw->hw_qtd_next == EHCI_LIST_END(ehci))
+ qh->exception = 1;
+
+ /* Let the caller know if the QH needs to be unlinked. */
+ return qh->exception;
+}
+
+/*-------------------------------------------------------------------------*/
+
+// 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) {
+ unsigned tmp;
+
+ qh->ps.usecs = NS_TO_US(usb_calc_bus_time(USB_SPEED_HIGH,
+ is_input, 0,
+ hb_mult(maxp) * max_packet(maxp)));
+ qh->ps.phase = NO_FRAME;
+
+ if (urb->dev->speed == USB_SPEED_HIGH) {
+ qh->ps.c_usecs = 0;
+ qh->gap_uf = 0;
+
+ if (urb->interval > 1 && urb->interval < 8) {
+ /* NOTE interval 2 or 4 uframes could work.
+ * But interval 1 scheduling is simpler, and
+ * includes high bandwidth.
+ */
+ urb->interval = 1;
+ } else if (urb->interval > ehci->periodic_size << 3) {
+ urb->interval = ehci->periodic_size << 3;
+ }
+ qh->ps.period = urb->interval >> 3;
+
+ /* period for bandwidth allocation */
+ tmp = min_t(unsigned, EHCI_BANDWIDTH_SIZE,
+ 1 << (urb->ep->desc.bInterval - 1));
+
+ /* Allow urb->interval to override */
+ qh->ps.bw_uperiod = min_t(unsigned, tmp, urb->interval);
+ qh->ps.bw_period = qh->ps.bw_uperiod >> 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->ps.c_usecs = qh->ps.usecs + HS_USECS(0);
+ qh->ps.usecs = HS_USECS(1);
+ } else { // SPLIT+DATA, gap, CSPLIT
+ qh->ps.usecs += HS_USECS(1);
+ qh->ps.c_usecs = HS_USECS(0);
+ }
+
+ think_time = tt ? tt->think_time : 0;
+ qh->ps.tt_usecs = NS_TO_US(think_time +
+ usb_calc_bus_time (urb->dev->speed,
+ is_input, 0, max_packet (maxp)));
+ if (urb->interval > ehci->periodic_size)
+ urb->interval = ehci->periodic_size;
+ qh->ps.period = urb->interval;
+
+ /* period for bandwidth allocation */
+ tmp = min_t(unsigned, EHCI_BANDWIDTH_FRAMES,
+ urb->ep->desc.bInterval);
+ tmp = rounddown_pow_of_two(tmp);
+
+ /* Allow urb->interval to override */
+ qh->ps.bw_period = min_t(unsigned, tmp, urb->interval);
+ qh->ps.bw_uperiod = qh->ps.bw_period << 3;
+ }
+ }
+
+ /* support for tt scheduling, and access to toggles */
+ qh->ps.udev = urb->dev;
+ qh->ps.ep = urb->ep;
+
+ /* 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 */
+ 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);
+ 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 unlink lists are supposed to be empty */
+ WARN_ON(ehci->async->qh_next.qh || !list_empty(&ehci->async_unlink) ||
+ !list_empty(&ehci->async_idle));
+
+ /* 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->qh_state = QH_STATE_LINKED;
+ qh->xacterrs = 0;
+ qh->exception = 0;
+ /* 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;
+}
+
+/*-------------------------------------------------------------------------*/
+#ifdef CONFIG_USB_HCD_TEST_MODE
+/*
+ * This function creates the qtds and submits them for the
+ * SINGLE_STEP_SET_FEATURE Test.
+ * This is done in two parts: first SETUP req for GetDesc is sent then
+ * 15 seconds later, the IN stage for GetDesc starts to req data from dev
+ *
+ * is_setup : i/p arguement decides which of the two stage needs to be
+ * performed; TRUE - SETUP and FALSE - IN+STATUS
+ * Returns 0 if success
+ */
+static int submit_single_step_set_feature(
+ struct usb_hcd *hcd,
+ struct urb *urb,
+ int is_setup
+) {
+ struct ehci_hcd *ehci = hcd_to_ehci(hcd);
+ struct list_head qtd_list;
+ struct list_head *head;
+
+ struct ehci_qtd *qtd, *qtd_prev;
+ dma_addr_t buf;
+ int len, maxpacket;
+ u32 token;
+
+ INIT_LIST_HEAD(&qtd_list);
+ head = &qtd_list;
+
+ /* URBs map to sequences of QTDs: one logical transaction */
+ qtd = ehci_qtd_alloc(ehci, GFP_KERNEL);
+ if (unlikely(!qtd))
+ return -1;
+ list_add_tail(&qtd->qtd_list, head);
+ qtd->urb = urb;
+
+ token = QTD_STS_ACTIVE;
+ token |= (EHCI_TUNE_CERR << 10);
+
+ len = urb->transfer_buffer_length;
+ /*
+ * Check if the request is to perform just the SETUP stage (getDesc)
+ * as in SINGLE_STEP_SET_FEATURE test, DATA stage (IN) happens
+ * 15 secs after the setup
+ */
+ if (is_setup) {
+ /* SETUP pid */
+ qtd_fill(ehci, qtd, urb->setup_dma,
+ sizeof(struct usb_ctrlrequest),
+ token | (2 /* "setup" */ << 8), 8);
+
+ submit_async(ehci, urb, &qtd_list, GFP_ATOMIC);
+ return 0; /*Return now; we shall come back after 15 seconds*/
+ }
+
+ /*
+ * IN: data transfer stage: buffer setup : start the IN txn phase for
+ * the get_Desc SETUP which was sent 15seconds back
+ */
+ token ^= QTD_TOGGLE; /*We need to start IN with DATA-1 Pid-sequence*/
+ buf = urb->transfer_dma;
+
+ token |= (1 /* "in" */ << 8); /*This is IN stage*/
+
+ maxpacket = max_packet(usb_maxpacket(urb->dev, urb->pipe, 0));
+
+ qtd_fill(ehci, qtd, buf, len, token, maxpacket);
+
+ /*
+ * Our IN phase shall always be a short read; so keep the queue running
+ * and let it advance to the next qtd which zero length OUT status
+ */
+ qtd->hw_alt_next = EHCI_LIST_END(ehci);
+
+ /* STATUS stage for GetDesc control request */
+ token ^= 0x0100; /* "in" <--> "out" */
+ token |= QTD_TOGGLE; /* force DATA1 */
+
+ qtd_prev = qtd;
+ qtd = ehci_qtd_alloc(ehci, GFP_ATOMIC);
+ 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);
+
+ /* dont fill 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);
+
+ submit_async(ehci, urb, &qtd_list, GFP_KERNEL);
+
+ return 0;
+
+cleanup:
+ qtd_list_free(ehci, urb, head);
+ return -1;
+}
+#endif /* CONFIG_USB_HCD_TEST_MODE */
+
+/*-------------------------------------------------------------------------*/
+
+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_WAIT;
+ list_add_tail(&qh->unlink_node, &ehci->async_unlink);
+
+ /* 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)
+{
+ /* Do nothing if an IAA cycle is already running */
+ if (ehci->iaa_in_progress)
+ return;
+ ehci->iaa_in_progress = true;
+
+ /* If the controller isn't running, we don't have to wait for it */
+ if (unlikely(ehci->rh_state < EHCI_RH_RUNNING)) {
+ end_unlink_async(ehci);
+
+ /* Otherwise start a new IAA cycle */
+ } else if (likely(ehci->rh_state == EHCI_RH_RUNNING)) {
+
+ /* 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;
+ bool early_exit;
+
+ if (ehci->has_synopsys_hc_bug)
+ ehci_writel(ehci, (u32) ehci->async->qh_dma,
+ &ehci->regs->async_next);
+
+ /* The current IAA cycle has ended */
+ ehci->iaa_in_progress = false;
+
+ if (list_empty(&ehci->async_unlink))
+ return;
+ qh = list_first_entry(&ehci->async_unlink, struct ehci_qh,
+ unlink_node); /* QH whose IAA cycle just ended */
+
+ /*
+ * If async_unlinking is set then this routine is already running,
+ * either on the stack or on another CPU.
+ */
+ early_exit = ehci->async_unlinking;
+
+ /* If the controller isn't running, process all the waiting QHs */
+ if (ehci->rh_state < EHCI_RH_RUNNING)
+ list_splice_tail_init(&ehci->async_unlink, &ehci->async_idle);
+
+ /*
+ * Intel (?) bug: The HC can write back the overlay region even
+ * after the IAA interrupt occurs. In self-defense, always go
+ * through two IAA cycles for each QH.
+ */
+ else if (qh->qh_state == QH_STATE_UNLINK_WAIT) {
+ qh->qh_state = QH_STATE_UNLINK;
+ early_exit = true;
+ }
+
+ /* Otherwise process only the first waiting QH (NVIDIA bug?) */
+ else
+ list_move_tail(&qh->unlink_node, &ehci->async_idle);
+
+ /* Start a new IAA cycle if any QHs are waiting for it */
+ if (!list_empty(&ehci->async_unlink))
+ start_iaa_cycle(ehci);
+
+ /*
+ * Don't allow nesting or concurrent calls,
+ * or wait for the second IAA cycle for the next QH.
+ */
+ if (early_exit)
+ return;
+
+ /* Process the idle QHs */
+ ehci->async_unlinking = true;
+ while (!list_empty(&ehci->async_idle)) {
+ qh = list_first_entry(&ehci->async_idle, struct ehci_qh,
+ unlink_node);
+ list_del(&qh->unlink_node);
+
+ qh->qh_state = QH_STATE_IDLE;
+ qh->qh_next.qh = NULL;
+
+ if (!list_empty(&qh->qtd_list))
+ 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;
+}
+
+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;
+ 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)
+ qh_to_unlink = qh;
+ }
+ }
+
+ /* If nothing else is being unlinked, unlink the last empty QH */
+ if (list_empty(&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;
+ }
+}
+
+/* The root hub is suspended; unlink all the async QHs */
+static void __maybe_unused unlink_empty_async_suspended(struct ehci_hcd *ehci)
+{
+ struct ehci_qh *qh;
+
+ while (ehci->async->qh_next.qh) {
+ qh = ehci->async->qh_next.qh;
+ WARN_ON(!list_empty(&qh->qtd_list));
+ single_unlink_async(ehci, qh);
+ }
+ start_iaa_cycle(ehci);
+}
+
+/* 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. */
+ if (qh->qh_state != QH_STATE_LINKED)
+ return;
+
+ single_unlink_async(ehci, qh);
+ start_iaa_cycle(ehci);
+}
+
+/*-------------------------------------------------------------------------*/
+
+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;
+
+ /* 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 (unlikely(temp)) {
+ 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;
+ }
+ }
+ }
+
+ /*
+ * 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;
+ }
+}
Code Review / kvmfornfv.git / blobdiff