patch-2.4.21 linux-2.4.21/drivers/usb/host/ehci-q.c

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diff -urN linux-2.4.20/drivers/usb/host/ehci-q.c linux-2.4.21/drivers/usb/host/ehci-q.c
@@ -0,0 +1,1107 @@
+/*
+ * Copyright (c) 2001-2002 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_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_le32 ((u32)addr);
+	qtd->hw_buf_hi [0] = cpu_to_le32 ((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_le32 ((u32)addr);
+			qtd->hw_buf_hi [i] = cpu_to_le32 ((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_le32 ((count << 16) | token);
+	qtd->length = count;
+
+	return count;
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* update halted (but potentially linked) qh */
+
+static inline void
+qh_update (struct ehci_hcd *ehci, struct ehci_qh *qh, struct ehci_qtd *qtd)
+{
+	qh->hw_current = 0;
+	qh->hw_qtd_next = QTD_NEXT (qtd->qtd_dma);
+	qh->hw_alt_next = EHCI_LIST_END;
+
+	/* HC must see latest qtd and qh data before we clear ACTIVE+HALT */
+	wmb ();
+	qh->hw_token &= __constant_cpu_to_le32 (QTD_TOGGLE | QTD_STS_PING);
+}
+
+/*-------------------------------------------------------------------------*/
+
+#define IS_SHORT_READ(token) (QTD_LENGTH (token) != 0 && QTD_PID (token) == 1)
+
+static void qtd_copy_status (
+	struct ehci_hcd *ehci,
+	struct urb *urb,
+	size_t length,
+	u32 token
+)
+{
+	/* 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->status != -EINPROGRESS))
+		return;
+
+	/* force cleanup after short read; not always an error */
+	if (unlikely (IS_SHORT_READ (token)))
+		urb->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 */
+			urb->status = -EOVERFLOW;
+		} else if (token & QTD_STS_MMF) {
+			/* fs/ls interrupt xfer missed the complete-split */
+			urb->status = -EPROTO;
+		} else if (token & QTD_STS_DBE) {
+			urb->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; retried */
+			if (QTD_CERR (token))
+				urb->status = -EPIPE;
+			else {
+				ehci_dbg (ehci, "devpath %s ep%d%s 3strikes\n",
+					urb->dev->devpath,
+					usb_pipeendpoint (urb->pipe),
+					usb_pipein (urb->pipe) ? "in" : "out");
+				urb->status = -EPROTO;
+			}
+		/* CERR nonzero + no errors + halt --> stall */
+		} else if (QTD_CERR (token))
+			urb->status = -EPIPE;
+		else	/* unknown */
+			urb->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, urb->status);
+
+		/* stall indicates some recovery action is needed */
+		if (urb->status == -EPIPE) {
+			int	pipe = urb->pipe;
+
+			if (!usb_pipecontrol (pipe))
+				usb_endpoint_halt (urb->dev,
+					usb_pipeendpoint (pipe),
+					usb_pipeout (pipe));
+			if (urb->dev->tt && !usb_pipeint (pipe)) {
+#ifdef DEBUG
+				struct usb_device *tt = urb->dev->tt->hub;
+				dbg ("clear tt %s-%s p%d buffer, a%d ep%d",
+					tt->bus->bus_name, tt->devpath,
+    					urb->dev->ttport, urb->dev->devnum,
+    					usb_pipeendpoint (pipe));
+#endif /* DEBUG */
+				usb_hub_tt_clear_buffer (urb->dev, pipe);
+			}
+		}
+	}
+}
+
+static void
+ehci_urb_done (struct ehci_hcd *ehci, struct urb *urb, struct pt_regs *regs)
+{
+#ifdef	INTR_AUTOMAGIC
+	struct urb		*resubmit = 0;
+	struct usb_device	*dev = 0;
+
+	static int ehci_urb_enqueue (struct usb_hcd *, struct urb *, int);
+#endif
+
+	if (likely (urb->hcpriv != 0)) {
+		struct ehci_qh	*qh = (struct ehci_qh *) urb->hcpriv;
+
+		/* S-mask in a QH means it's an interrupt urb */
+		if ((qh->hw_info2 & cpu_to_le32 (0x00ff)) != 0) {
+
+			/* ... update hc-wide periodic stats (for usbfs) */
+			hcd_to_bus (&ehci->hcd)->bandwidth_int_reqs--;
+
+#ifdef	INTR_AUTOMAGIC
+			if (!((urb->status == -ENOENT)
+					|| (urb->status == -ECONNRESET))) {
+				resubmit = usb_get_urb (urb);
+				dev = urb->dev;
+			}
+#endif
+		}
+		qh_put (ehci, qh);
+	}
+
+	spin_lock (&urb->lock);
+	urb->hcpriv = 0;
+	switch (urb->status) {
+	case -EINPROGRESS:		/* success */
+		urb->status = 0;
+	default:			/* fault */
+		COUNT (ehci->stats.complete);
+		break;
+	case -EREMOTEIO:		/* fault or normal */
+		if (!(urb->transfer_flags & URB_SHORT_NOT_OK))
+			urb->status = 0;
+		COUNT (ehci->stats.complete);
+		break;
+	case -ECONNRESET:		/* canceled */
+	case -ENOENT:
+		COUNT (ehci->stats.unlink);
+		break;
+	}
+	spin_unlock (&urb->lock);
+
+	/* complete() can reenter this HCD */
+	spin_unlock (&ehci->lock);
+	usb_hcd_giveback_urb (&ehci->hcd, urb, regs);
+
+#ifdef	INTR_AUTOMAGIC
+	if (resubmit && ((urb->status == -ENOENT)
+				|| (urb->status == -ECONNRESET))) {
+		usb_put_urb (resubmit);
+		resubmit = 0;
+	}
+	// device drivers will soon be doing something like this
+	if (resubmit) {
+		int	status;
+
+		resubmit->dev = dev;
+		status = SUBMIT_URB (resubmit, SLAB_ATOMIC);
+		if (status != 0)
+			err ("can't resubmit interrupt urb %p: status %d",
+					resubmit, status);
+		usb_put_urb (resubmit);
+	}
+#endif
+
+	spin_lock (&ehci->lock);
+}
+
+
+/*
+ * 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.
+ */
+#define HALT_BIT cpu_to_le32(QTD_STS_HALT)
+static unsigned
+qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh, struct pt_regs *regs)
+{
+	struct ehci_qtd		*last = 0, *end = qh->dummy;
+	struct list_head	*entry, *tmp;
+	int			stopped;
+	unsigned		count = 0;
+	int			do_status = 0;
+	u8			state;
+
+	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.
+	 */
+	state = qh->qh_state;
+	qh->qh_state = QH_STATE_COMPLETING;
+	stopped = (state == QH_STATE_IDLE);
+
+	/* 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, regs);
+				count++;
+			}
+			ehci_qtd_free (ehci, last);
+			last = 0;
+		}
+
+		/* ignore urbs submitted during completions we reported */
+		if (qtd == end)
+			break;
+
+		/* hardware copies qtd out of qh overlay */
+		rmb ();
+		token = le32_to_cpu (qtd->hw_token);
+		stopped = stopped
+			|| (HALT_BIT & qh->hw_token) != 0
+			|| (ehci->hcd.state == USB_STATE_HALT);
+
+		/* always clean up qtds the hc de-activated */
+		if ((token & QTD_STS_ACTIVE) == 0) {
+
+			/* magic dummy for short reads; won't advance */
+			if (IS_SHORT_READ (token)
+					&& !(token & QTD_STS_HALT)
+					&& (qh->hw_alt_next & QTD_MASK)
+						== ehci->async->hw_alt_next) {
+				stopped = 1;
+				goto halt;
+			}
+
+		/* stop scanning when we reach qtds the hc is using */
+		} else if (likely (!stopped)) {
+			break;
+
+		} else {
+			/* ignore active urbs unless some previous qtd
+			 * for the urb faulted (including short read) or
+			 * its urb was canceled.  we may patch qh or qtds.
+			 */
+			if (likely (urb->status == -EINPROGRESS))
+				continue;
+			
+			/* issue status after short control reads */
+			if (unlikely (do_status != 0)
+					&& QTD_PID (token) == 0 /* OUT */) {
+				do_status = 0;
+				continue;
+			}
+
+			/* token in overlay may be most current */
+			if (state == QH_STATE_IDLE
+					&& cpu_to_le32 (qtd->qtd_dma)
+						== qh->hw_current)
+				token = le32_to_cpu (qh->hw_token);
+
+			/* force halt for unlinked or blocked qh, so we'll
+			 * patch the qh later and so that completions can't
+			 * activate it while we "know" it's stopped.
+			 */
+			if ((HALT_BIT & qh->hw_token) == 0) {
+halt:
+				qh->hw_token |= HALT_BIT;
+				wmb ();
+			}
+		}
+ 
+		/* remove it from the queue */
+		spin_lock (&urb->lock);
+		qtd_copy_status (ehci, urb, qtd->length, token);
+		do_status = (urb->status == -EREMOTEIO)
+				&& usb_pipecontrol (urb->pipe);
+		spin_unlock (&urb->lock);
+
+		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;
+		}
+		list_del (&qtd->qtd_list);
+		last = qtd;
+	}
+
+	/* last urb's completion might still need calling */
+	if (likely (last != 0)) {
+		ehci_urb_done (ehci, last->urb, regs);
+		count++;
+		ehci_qtd_free (ehci, last);
+	}
+
+	/* restore original state; caller must unlink or relink */
+	qh->qh_state = state;
+
+	/* update qh after fault cleanup */
+	if (unlikely ((HALT_BIT & qh->hw_token) != 0)) {
+		qh_update (ehci, qh,
+			list_empty (&qh->qtd_list)
+				? qh->dummy
+				: list_entry (qh->qtd_list.next,
+					struct ehci_qtd, qtd_list));
+	}
+
+	return count;
+}
+#undef HALT_BIT
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * 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,
+	int			flags
+) {
+	struct ehci_qtd		*qtd, *qtd_prev;
+	dma_addr_t		buf;
+	int			len, maxpacket;
+	int			is_input;
+	u32			token;
+
+	/*
+	 * URBs map to sequences of QTDs:  one logical transaction
+	 */
+	qtd = ehci_qtd_alloc (ehci, flags);
+	if (unlikely (!qtd))
+		return 0;
+	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 (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 (qtd->qtd_dma);
+		list_add_tail (&qtd->qtd_list, head);
+	} 
+
+	/*
+	 * data transfer stage:  buffer setup
+	 */
+	if (likely (len > 0))
+		buf = urb->transfer_dma;
+	else
+		buf = 0;
+
+	// FIXME this 'buf' check break some zlps...
+	if (!buf || is_input)
+		token |= (1 /* "in" */ << 8);
+	/* else it's already initted to "out" pid (0 << 8) */
+
+	maxpacket = usb_maxpacket (urb->dev, urb->pipe, !is_input) & 0x03ff;
+
+	/*
+	 * 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 (qtd, buf, len, token, maxpacket);
+		len -= this_qtd_len;
+		buf += this_qtd_len;
+		if (is_input)
+			qtd->hw_alt_next = ehci->async->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 (len <= 0))
+			break;
+
+		qtd_prev = qtd;
+		qtd = ehci_qtd_alloc (ehci, flags);
+		if (unlikely (!qtd))
+			goto cleanup;
+		qtd->urb = urb;
+		qtd_prev->hw_next = QTD_NEXT (qtd->qtd_dma);
+		list_add_tail (&qtd->qtd_list, head);
+	}
+
+	/* unless the bulk/interrupt caller wants a chance to clean
+	 * up after short reads, hc should advance qh past this urb
+	 */
+	if (likely ((urb->transfer_flags & URB_SHORT_NOT_OK) == 0
+				|| usb_pipecontrol (urb->pipe)))
+		qtd->hw_alt_next = EHCI_LIST_END;
+
+	/*
+	 * control requests may need a terminating data "status" ack;
+	 * bulk ones may need a terminating short packet (zero length).
+	 */
+	if (likely (buf != 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_pipebulk (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 (qtd->qtd_dma);
+			list_add_tail (&qtd->qtd_list, head);
+
+			/* never any data in such packets */
+			qtd_fill (qtd, 0, 0, token, 0);
+		}
+	}
+
+	/* by default, enable interrupt on urb completion */
+	if (likely (!(urb->transfer_flags & URB_NO_INTERRUPT)))
+		qtd->hw_token |= __constant_cpu_to_le32 (QTD_IOC);
+	return head;
+
+cleanup:
+	qtd_list_free (ehci, urb, head);
+	return 0;
+}
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * Hardware maintains data toggle (like OHCI) ... here we (re)initialize
+ * the hardware data toggle in the QH, and set the pseudo-toggle in udev
+ * so we can see if usb_clear_halt() was called.  NOP for control, since
+ * we set up qh->hw_info1 to always use the QTD toggle bits. 
+ */
+static inline void
+clear_toggle (struct usb_device *udev, int ep, int is_out, struct ehci_qh *qh)
+{
+	vdbg ("clear toggle, dev %d ep 0x%x-%s",
+		udev->devnum, ep, is_out ? "out" : "in");
+	qh->hw_token &= ~__constant_cpu_to_le32 (QTD_TOGGLE);
+	usb_settoggle (udev, ep, is_out, 1);
+}
+
+// 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. (2.5?)
+
+
+// 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) & 0x03ff)
+
+/*
+ * 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,
+	int			flags
+) {
+	struct ehci_qh		*qh = ehci_qh_alloc (ehci, flags);
+	u32			info1 = 0, info2 = 0;
+	int			is_input, type;
+	int			maxp = 0;
+
+	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);
+
+	/* 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 = 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;
+
+			/* FIXME handle HS periods of less than 1 frame. */
+			qh->period = urb->interval >> 3;
+			if (qh->period < 1) {
+				dbg ("intr period %d uframes, NYET!",
+						urb->interval);
+				goto done;
+			}
+		} else {
+			/* 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);
+			}
+
+			qh->period = urb->interval;
+		}
+	}
+
+	/* using TT? */
+	switch (urb->dev->speed) {
+	case USB_SPEED_LOW:
+		info1 |= (1 << 12);	/* EPS "low" */
+		/* 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 |= (1 << 27);	/* for TT */
+			info1 |= 1 << 14;	/* toggle from qtd */
+		}
+		info1 |= maxp << 16;
+
+		info2 |= (EHCI_TUNE_MULT_TT << 30);
+		info2 |= urb->dev->ttport << 23;
+		info2 |= urb->dev->tt->hub->devnum << 16;
+
+		/* NOTE:  if (PIPE_INTERRUPT) { scheduler sets c-mask } */
+
+		break;
+
+	case USB_SPEED_HIGH:		/* no TT involved */
+		info1 |= (2 << 12);	/* EPS "high" */
+		if (type == PIPE_CONTROL) {
+			info1 |= (EHCI_TUNE_RL_HS << 28);
+			info1 |= 64 << 16;	/* usb2 fixed maxpacket */
+			info1 |= 1 << 14;	/* toggle from qtd */
+			info2 |= (EHCI_TUNE_MULT_HS << 30);
+		} else if (type == PIPE_BULK) {
+			info1 |= (EHCI_TUNE_RL_HS << 28);
+			info1 |= 512 << 16;	/* usb2 fixed maxpacket */
+			info2 |= (EHCI_TUNE_MULT_HS << 30);
+		} else {		/* PIPE_INTERRUPT */
+			info1 |= max_packet (maxp) << 16;
+			info2 |= hb_mult (maxp) << 30;
+		}
+		break;
+	default:
+ 		dbg ("bogus dev %p speed %d", urb->dev, urb->dev->speed);
+done:
+		qh_put (ehci, qh);
+		return 0;
+	}
+
+	/* NOTE:  if (PIPE_INTERRUPT) { scheduler sets s-mask } */
+
+	/* init as halted, toggle clear, advance to dummy */
+	qh->qh_state = QH_STATE_IDLE;
+	qh->hw_info1 = cpu_to_le32 (info1);
+	qh->hw_info2 = cpu_to_le32 (info2);
+	qh_update (ehci, qh, qh->dummy);
+	qh->hw_token = cpu_to_le32 (QTD_STS_HALT);
+	usb_settoggle (urb->dev, usb_pipeendpoint (urb->pipe), !is_input, 1);
+	return qh;
+}
+#undef hb_mult
+#undef hb_packet
+
+/*-------------------------------------------------------------------------*/
+
+/* move qh (and its qtds) onto async queue; maybe enable queue.  */
+
+static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
+{
+	u32		dma = QH_NEXT (qh->qh_dma);
+	struct ehci_qh	*head;
+
+	/* (re)start the async schedule? */
+	head = ehci->async;
+	if (ehci->async_idle)
+		del_timer (&ehci->watchdog);
+	if (!head->qh_next.qh) {
+		u32	cmd = readl (&ehci->regs->command);
+
+		if (!(cmd & CMD_ASE)) {
+			/* in case a clear of CMD_ASE didn't take yet */
+			(void) handshake (&ehci->regs->status, STS_ASS, 0, 150);
+
+			/* force async head to be valid */
+			writel ((u32)ehci->async->qh_dma,
+					&ehci->regs->async_next);
+
+			cmd |= CMD_ASE | CMD_RUN;
+			writel (cmd, &ehci->regs->command);
+			ehci->hcd.state = USB_STATE_RUNNING;
+			/* posted write need not be known to HC yet ... */
+		}
+	}
+
+	qh->hw_token &= ~__constant_cpu_to_le32 (QTD_STS_HALT);
+
+	/* splice right after start */
+	qh->qh_next = head->qh_next;
+	qh->hw_next = head->hw_next;
+	wmb ();
+
+	head->qh_next.qh = qh;
+	head->hw_next = dma;
+
+	qh->qh_state = QH_STATE_LINKED;
+	/* qtd completions reported later by interrupt */
+
+	ehci->async_idle = 0;
+}
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * 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 = 0;
+
+	qh = (struct ehci_qh *) *ptr;
+	if (unlikely (qh == 0)) {
+		/* can't sleep here, we have ehci->lock... */
+		qh = qh_make (ehci, urb, SLAB_ATOMIC);
+		*ptr = qh;
+	}
+	if (likely (qh != 0)) {
+		struct ehci_qtd	*qtd;
+
+		if (unlikely (list_empty (qtd_list)))
+			qtd = 0;
+		else
+			qtd = list_entry (qtd_list->next, struct ehci_qtd,
+					qtd_list);
+
+		/* control qh may need patching after enumeration */
+		if (unlikely (epnum == 0)) {
+			/* set_address changes the address */
+			if (le32_to_cpu (qh->hw_info1 & 0x7f) == 0)
+				qh->hw_info1 |= cpu_to_le32 (
+						usb_pipedevice (urb->pipe));
+
+			/* for full speed, ep0 maxpacket can grow */
+			else if (!(qh->hw_info1 & cpu_to_le32 (0x3 << 12))) {
+				u32	info, max;
+
+				info = le32_to_cpu (qh->hw_info1);
+				max = urb->dev->descriptor.bMaxPacketSize0;
+				if (max > (0x07ff & (info >> 16))) {
+					info &= ~(0x07ff << 16);
+					info |= max << 16;
+					qh->hw_info1 = cpu_to_le32 (info);
+				}
+			}
+		}
+
+		/* FIXME:  changing config or interface setting is not
+		 * supported yet.  preferred fix is for usbcore to tell
+		 * us to clear out each endpoint's state, but...
+		 */
+
+		/* usb_clear_halt() means qh data toggle gets reset */
+		if (unlikely (!usb_gettoggle (urb->dev,
+					(epnum & 0x0f), !(epnum & 0x10)))
+				&& !usb_pipecontrol (urb->pipe)) {
+			/* "never happens": drivers do stall cleanup right */
+			if (qh->qh_state != QH_STATE_IDLE
+					&& !list_empty (&qh->qtd_list)
+					&& qh->qh_state != QH_STATE_COMPLETING)
+				ehci_warn (ehci, "clear toggle dev%d "
+						"ep%d%s: not idle\n",
+						usb_pipedevice (urb->pipe),
+						epnum & 0x0f,
+						usb_pipein (urb->pipe)
+							? "in" : "out");
+			/* else we know this overlay write is safe */
+			clear_toggle (urb->dev,
+				epnum & 0x0f, !(epnum & 0x10), qh);
+		}
+
+		/* just one way to queue requests: swap with the dummy qtd.
+		 * only hc or qh_completions() usually modify the overlay.
+		 */
+		if (likely (qtd != 0)) {
+			struct ehci_qtd		*dummy;
+			dma_addr_t		dma;
+			u32			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 = cpu_to_le32 (QTD_STS_HALT);
+			wmb ();
+			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 (qtd_list, qh->qtd_list.prev);
+
+			ehci_qtd_init (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 (dma);
+
+			/* let the hc process these next qtds */
+			wmb ();
+			dummy->hw_token = token;
+
+			urb->hcpriv = qh_get (qh);
+		}
+	}
+	return qh;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int
+submit_async (
+	struct ehci_hcd		*ehci,
+	struct urb		*urb,
+	struct list_head	*qtd_list,
+	int			mem_flags
+) {
+	struct ehci_qtd		*qtd;
+	struct hcd_dev		*dev;
+	int			epnum;
+	unsigned long		flags;
+	struct ehci_qh		*qh = 0;
+
+	qtd = list_entry (qtd_list->next, struct ehci_qtd, qtd_list);
+	dev = (struct hcd_dev *)urb->dev->hcpriv;
+	epnum = usb_pipeendpoint (urb->pipe);
+	if (usb_pipein (urb->pipe) && !usb_pipecontrol (urb->pipe))
+		epnum |= 0x10;
+
+	ehci_vdbg (ehci, "submit_async urb %p len %d ep%d%s qtd %p [qh %p]\n",
+		urb, urb->transfer_buffer_length,
+		epnum & 0x0f, (epnum & 0x10) ? "in" : "out",
+		qtd, dev ? dev->ep [epnum] : (void *)~0);
+
+	spin_lock_irqsave (&ehci->lock, flags);
+	qh = qh_append_tds (ehci, urb, qtd_list, epnum, &dev->ep [epnum]);
+
+	/* 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 != 0)) {
+		if (likely (qh->qh_state == QH_STATE_IDLE))
+			qh_link_async (ehci, qh_get (qh));
+	}
+	spin_unlock_irqrestore (&ehci->lock, flags);
+	if (unlikely (qh == 0)) {
+		qtd_list_free (ehci, urb, qtd_list);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* the async qh for the qtds being reclaimed are now unlinked from the HC */
+
+static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh);
+
+static void end_unlink_async (struct ehci_hcd *ehci, struct pt_regs *regs)
+{
+	struct ehci_qh		*qh = ehci->reclaim;
+	struct ehci_qh		*next;
+
+	del_timer (&ehci->watchdog);
+
+	// qh->hw_next = cpu_to_le32 (qh->qh_dma);
+	qh->qh_state = QH_STATE_IDLE;
+	qh->qh_next.qh = 0;
+	qh_put (ehci, qh);			// refcount from reclaim 
+	ehci->reclaim = 0;
+	ehci->reclaim_ready = 0;
+
+	/* other unlink(s) may be pending (in QH_STATE_UNLINK_WAIT) */
+	next = qh->reclaim;
+	qh->reclaim = 0;
+
+	qh_completions (ehci, qh, regs);
+
+	if (!list_empty (&qh->qtd_list)
+			&& HCD_IS_RUNNING (ehci->hcd.state))
+		qh_link_async (ehci, qh);
+	else {
+		qh_put (ehci, qh);		// refcount from async list
+
+		/* it's not free to turn the async schedule on/off; leave it
+		 * active but idle for a while once it empties.
+		 */
+		if (HCD_IS_RUNNING (ehci->hcd.state)
+				&& ehci->async->qh_next.qh == 0
+				&& !timer_pending (&ehci->watchdog)) {
+			ehci->async_idle = 1;
+			mod_timer (&ehci->watchdog,
+					jiffies + EHCI_ASYNC_JIFFIES);
+		}
+	}
+
+	if (next)
+		start_unlink_async (ehci, next);
+}
+
+/* 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)
+{
+	int		cmd = readl (&ehci->regs->command);
+	struct ehci_qh	*prev;
+
+#ifdef DEBUG
+	if (ehci->reclaim
+			|| (qh->qh_state != QH_STATE_LINKED
+				&& qh->qh_state != QH_STATE_UNLINK_WAIT)
+#ifdef CONFIG_SMP
+// this macro lies except on SMP compiles
+			|| !spin_is_locked (&ehci->lock)
+#endif
+			)
+		BUG ();
+#endif
+
+	/* stop async schedule right now? */
+	if (unlikely (qh == ehci->async)) {
+		/* can't get here without STS_ASS set */
+		if (ehci->hcd.state != USB_STATE_HALT) {
+			writel (cmd & ~CMD_ASE, &ehci->regs->command);
+			wmb ();
+			// handshake later, if we need to
+		}
+		return;
+	} 
+
+	qh->qh_state = QH_STATE_UNLINK;
+	ehci->reclaim = qh = qh_get (qh);
+
+	prev = ehci->async;
+	while (prev->qh_next.qh != qh)
+		prev = prev->qh_next.qh;
+
+	prev->hw_next = qh->hw_next;
+	prev->qh_next = qh->qh_next;
+	wmb ();
+
+	if (unlikely (ehci->hcd.state == USB_STATE_HALT)) {
+		/* if (unlikely (qh->reclaim != 0))
+		 * 	this will recurse, probably not much
+		 */
+		end_unlink_async (ehci, NULL);
+		return;
+	}
+
+	ehci->reclaim_ready = 0;
+	cmd |= CMD_IAAD;
+	writel (cmd, &ehci->regs->command);
+	/* posted write need not be known to HC yet ... */
+
+	mod_timer (&ehci->watchdog, jiffies + EHCI_WATCHDOG_JIFFIES);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void
+scan_async (struct ehci_hcd *ehci, struct pt_regs *regs)
+{
+	struct ehci_qh		*qh;
+	int			unlink_delay = 0;
+
+	if (!++(ehci->stamp))
+		ehci->stamp++;
+rescan:
+	qh = ehci->async->qh_next.qh;
+	if (likely (qh != 0)) {
+		do {
+			/* clean any finished work for this qh */
+			if (!list_empty (&qh->qtd_list)
+					&& qh->stamp != ehci->stamp) {
+				int temp;
+
+				/* unlinks could happen here; completion
+				 * reporting drops the lock.  rescan using
+				 * the latest schedule, but don't rescan
+				 * qhs we already finished (no looping).
+				 */
+				qh = qh_get (qh);
+				qh->stamp = ehci->stamp;
+				temp = qh_completions (ehci, qh, regs);
+				qh_put (ehci, qh);
+				if (temp != 0) {
+					goto rescan;
+				}
+			}
+
+			/* unlink idle entries, reducing HC PCI 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.
+			 * (plus, avoids some kind of re-activation race.)
+			 */
+			if (list_empty (&qh->qtd_list)) {
+				if (qh->stamp == ehci->stamp)
+					unlink_delay = 1;
+				else if (!ehci->reclaim) {
+					start_unlink_async (ehci, qh);
+					unlink_delay = 0;
+				}
+			}
+
+			qh = qh->qh_next.qh;
+		} while (qh);
+	}
+
+	if (unlink_delay && !timer_pending (&ehci->watchdog))
+		mod_timer (&ehci->watchdog, jiffies + EHCI_WATCHDOG_JIFFIES/2);
+}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)