[PATCH] UHCI: use one QH per endpoint, not per URB

This patch (as623) changes the uhci-hcd driver to make it use one QH per
device endpoint, instead of a QH per URB as it does now.  Numerous areas
of the code are affected by this.  For example, the distinction between
"queued" URBs and non-"queued" URBs no longer exists; all URBs belong to
a queue and some just happen to be at the queue's head.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/uhci-debug.c

@@ -90,13 +90,60 @@ static int uhci_show_td(struct uhci_td *td, char *buf, int len, int space)
 	return out - buf;
 }
 
-static int uhci_show_qh(struct uhci_qh *qh, char *buf, int len, int space)
+static int uhci_show_urbp(struct urb_priv *urbp, char *buf, int len, int space)
 {
 	char *out = buf;
-	struct urb_priv *urbp;
-	struct list_head *head, *tmp;
 	struct uhci_td *td;
-	int i = 0, checked = 0, prevactive = 0;
+	int i, nactive, ninactive;
+
+	if (len < 200)
+		return 0;
+
+	out += sprintf(out, "urb_priv [%p] ", urbp);
+	out += sprintf(out, "urb [%p] ", urbp->urb);
+	out += sprintf(out, "qh [%p] ", urbp->qh);
+	out += sprintf(out, "Dev=%d ", usb_pipedevice(urbp->urb->pipe));
+	out += sprintf(out, "EP=%x(%s) ", usb_pipeendpoint(urbp->urb->pipe),
+			(usb_pipein(urbp->urb->pipe) ? "IN" : "OUT"));
+
+	switch (usb_pipetype(urbp->urb->pipe)) {
+	case PIPE_ISOCHRONOUS: out += sprintf(out, "ISO"); break;
+	case PIPE_INTERRUPT: out += sprintf(out, "INT"); break;
+	case PIPE_BULK: out += sprintf(out, "BLK"); break;
+	case PIPE_CONTROL: out += sprintf(out, "CTL"); break;
+	}
+
+	out += sprintf(out, "%s", (urbp->fsbr ? " FSBR" : ""));
+	out += sprintf(out, "%s", (urbp->fsbr_timeout ? " FSBR_TO" : ""));
+
+	if (urbp->urb->status != -EINPROGRESS)
+		out += sprintf(out, " Status=%d", urbp->urb->status);
+	out += sprintf(out, "\n");
+
+	i = nactive = ninactive = 0;
+	list_for_each_entry(td, &urbp->td_list, list) {
+		if (++i <= 10 || debug > 2) {
+			out += sprintf(out, "%*s%d: ", space + 2, "", i);
+			out += uhci_show_td(td, out, len - (out - buf), 0);
+		} else {
+			if (td_status(td) & TD_CTRL_ACTIVE)
+				++nactive;
+			else
+				++ninactive;
+		}
+	}
+	if (nactive + ninactive > 0)
+		out += sprintf(out, "%*s[skipped %d inactive and %d active "
+				"TDs]\n",
+				space, "", ninactive, nactive);
+
+	return out - buf;
+}
+
+static int uhci_show_qh(struct uhci_qh *qh, char *buf, int len, int space)
+{
+	char *out = buf;
+	int i, nurbs;
 	__le32 element = qh_element(qh);
 
 	/* Try to make sure there's enough memory */
@@ -118,86 +165,36 @@ static int uhci_show_qh(struct uhci_qh *qh, char *buf, int len, int space)
 	if (!(element & ~(UHCI_PTR_QH | UHCI_PTR_DEPTH)))
 		out += sprintf(out, "%*s  Element is NULL (bug?)\n", space, "");
 
-	if (!qh->urbp) {
-		out += sprintf(out, "%*s  urbp == NULL\n", space, "");
-		goto out;
-	}
-
-	urbp = qh->urbp;
-
-	head = &urbp->td_list;
-	tmp = head->next;
-
-	td = list_entry(tmp, struct uhci_td, list);
-
-	if (cpu_to_le32(td->dma_handle) != (element & ~UHCI_PTR_BITS))
-		out += sprintf(out, "%*s Element != First TD\n", space, "");
-
-	while (tmp != head) {
-		struct uhci_td *td = list_entry(tmp, struct uhci_td, list);
-
-		tmp = tmp->next;
-
-		out += sprintf(out, "%*s%d: ", space + 2, "", i++);
-		out += uhci_show_td(td, out, len - (out - buf), 0);
-
-		if (i > 10 && !checked && prevactive && tmp != head &&
-		    debug <= 2) {
-			struct list_head *ntmp = tmp;
-			struct uhci_td *ntd = td;
-			int active = 1, ni = i;
-
-			checked = 1;
-
-			while (ntmp != head && ntmp->next != head && active) {
-				ntd = list_entry(ntmp, struct uhci_td, list);
-
-				ntmp = ntmp->next;
-
-				active = td_status(ntd) & TD_CTRL_ACTIVE;
-
-				ni++;
-			}
-
-			if (active && ni > i) {
-				out += sprintf(out, "%*s[skipped %d active TDs]\n", space, "", ni - i);
-				tmp = ntmp;
-				td = ntd;
-				i = ni;
-			}
+	if (list_empty(&qh->queue)) {
+		out += sprintf(out, "%*s  queue is empty\n", space, "");
+	} else {
+		struct urb_priv *urbp = list_entry(qh->queue.next,
+				struct urb_priv, node);
+		struct uhci_td *td = list_entry(urbp->td_list.next,
+				struct uhci_td, list);
+
+		if (cpu_to_le32(td->dma_handle) != (element & ~UHCI_PTR_BITS))
+			out += sprintf(out, "%*s Element != First TD\n",
+					space, "");
+		i = nurbs = 0;
+		list_for_each_entry(urbp, &qh->queue, node) {
+			if (++i <= 10)
+				out += uhci_show_urbp(urbp, out,
+						len - (out - buf), space + 2);
+			else
+				++nurbs;
 		}
-
-		prevactive = td_status(td) & TD_CTRL_ACTIVE;
-	}
-
-	if (list_empty(&urbp->queue_list) || urbp->queued)
-		goto out;
-
-	out += sprintf(out, "%*sQueued QHs:\n", -space, "--");
-
-	head = &urbp->queue_list;
-	tmp = head->next;
-
-	while (tmp != head) {
-		struct urb_priv *nurbp = list_entry(tmp, struct urb_priv,
-						queue_list);
-		tmp = tmp->next;
-
-		out += uhci_show_qh(nurbp->qh, out, len - (out - buf), space);
+		if (nurbs > 0)
+			out += sprintf(out, "%*s Skipped %d URBs\n",
+					space, "", nurbs);
 	}
 
-out:
 	return out - buf;
 }
 
-#define show_frame_num()	\
-	if (!shown) {		\
-	  shown = 1;		\
-	  out += sprintf(out, "- Frame %d\n", i); \
-	}
-
 #ifdef CONFIG_PROC_FS
 static const char * const qh_names[] = {
+  "skel_unlink_qh", "skel_iso_qh",
   "skel_int128_qh", "skel_int64_qh",
   "skel_int32_qh", "skel_int16_qh",
   "skel_int8_qh", "skel_int4_qh",
@@ -206,12 +203,6 @@ static const char * const qh_names[] = {
   "skel_bulk_qh", "skel_term_qh"
 };
 
-#define show_qh_name()		\
-	if (!shown) {		\
-	  shown = 1;		\
-	  out += sprintf(out, "- %s\n", qh_names[i]); \
-	}
-
 static int uhci_show_sc(int port, unsigned short status, char *buf, int len)
 {
 	char *out = buf;
@@ -321,139 +312,29 @@ static int uhci_show_status(struct uhci_hcd *uhci, char *buf, int len)
 	return out - buf;
 }
 
-static int uhci_show_urbp(struct uhci_hcd *uhci, struct urb_priv *urbp, char *buf, int len)
-{
-	struct list_head *tmp;
-	char *out = buf;
-	int count = 0;
-
-	if (len < 200)
-		return 0;
-
-	out += sprintf(out, "urb_priv [%p] ", urbp);
-	out += sprintf(out, "urb [%p] ", urbp->urb);
-	out += sprintf(out, "qh [%p] ", urbp->qh);
-	out += sprintf(out, "Dev=%d ", usb_pipedevice(urbp->urb->pipe));
-	out += sprintf(out, "EP=%x(%s) ", usb_pipeendpoint(urbp->urb->pipe), (usb_pipein(urbp->urb->pipe) ? "IN" : "OUT"));
-
-	switch (usb_pipetype(urbp->urb->pipe)) {
-	case PIPE_ISOCHRONOUS: out += sprintf(out, "ISO "); break;
-	case PIPE_INTERRUPT: out += sprintf(out, "INT "); break;
-	case PIPE_BULK: out += sprintf(out, "BLK "); break;
-	case PIPE_CONTROL: out += sprintf(out, "CTL "); break;
-	}
-
-	out += sprintf(out, "%s", (urbp->fsbr ? "FSBR " : ""));
-	out += sprintf(out, "%s", (urbp->fsbr_timeout ? "FSBR_TO " : ""));
-
-	if (urbp->urb->status != -EINPROGRESS)
-		out += sprintf(out, "Status=%d ", urbp->urb->status);
-	//out += sprintf(out, "FSBRtime=%lx ",urbp->fsbrtime);
-
-	count = 0;
-	list_for_each(tmp, &urbp->td_list)
-		count++;
-	out += sprintf(out, "TDs=%d ",count);
-
-	if (urbp->queued)
-		out += sprintf(out, "queued\n");
-	else {
-		count = 0;
-		list_for_each(tmp, &urbp->queue_list)
-			count++;
-		out += sprintf(out, "queued URBs=%d\n", count);
-	}
-
-	return out - buf;
-}
-
-static int uhci_show_lists(struct uhci_hcd *uhci, char *buf, int len)
-{
-	char *out = buf;
-	struct list_head *head, *tmp;
-	int count;
-
-	out += sprintf(out, "Main list URBs:");
-	if (list_empty(&uhci->urb_list))
-		out += sprintf(out, " Empty\n");
-	else {
-		out += sprintf(out, "\n");
-		count = 0;
-		head = &uhci->urb_list;
-		tmp = head->next;
-		while (tmp != head) {
-			struct urb_priv *urbp = list_entry(tmp, struct urb_priv, urb_list);
-
-			out += sprintf(out, "  %d: ", ++count);
-			out += uhci_show_urbp(uhci, urbp, out, len - (out - buf));
-			tmp = tmp->next;
-		}
-	}
-
-	out += sprintf(out, "Remove list URBs:");
-	if (list_empty(&uhci->urb_remove_list))
-		out += sprintf(out, " Empty\n");
-	else {
-		out += sprintf(out, "\n");
-		count = 0;
-		head = &uhci->urb_remove_list;
-		tmp = head->next;
-		while (tmp != head) {
-			struct urb_priv *urbp = list_entry(tmp, struct urb_priv, urb_list);
-
-			out += sprintf(out, "  %d: ", ++count);
-			out += uhci_show_urbp(uhci, urbp, out, len - (out - buf));
-			tmp = tmp->next;
-		}
-	}
-
-	out += sprintf(out, "Complete list URBs:");
-	if (list_empty(&uhci->complete_list))
-		out += sprintf(out, " Empty\n");
-	else {
-		out += sprintf(out, "\n");
-		count = 0;
-		head = &uhci->complete_list;
-		tmp = head->next;
-		while (tmp != head) {
-			struct urb_priv *urbp = list_entry(tmp, struct urb_priv, urb_list);
-
-			out += sprintf(out, "  %d: ", ++count);
-			out += uhci_show_urbp(uhci, urbp, out, len - (out - buf));
-			tmp = tmp->next;
-		}
-	}
-
-	return out - buf;
-}
-
 static int uhci_sprint_schedule(struct uhci_hcd *uhci, char *buf, int len)
 {
-	unsigned long flags;
 	char *out = buf;
 	int i, j;
 	struct uhci_qh *qh;
 	struct uhci_td *td;
 	struct list_head *tmp, *head;
 
-	spin_lock_irqsave(&uhci->lock, flags);
-
 	out += uhci_show_root_hub_state(uhci, out, len - (out - buf));
 	out += sprintf(out, "HC status\n");
 	out += uhci_show_status(uhci, out, len - (out - buf));
+	if (debug <= 1)
+		return out - buf;
 
 	out += sprintf(out, "Frame List\n");
 	for (i = 0; i < UHCI_NUMFRAMES; ++i) {
-		int shown = 0;
 		td = uhci->frame_cpu[i];
 		if (!td)
 			continue;
 
-		if (td->dma_handle != (dma_addr_t)uhci->frame[i]) {
-			show_frame_num();
+		out += sprintf(out, "- Frame %d\n", i); \
+		if (td->dma_handle != (dma_addr_t)uhci->frame[i])
 			out += sprintf(out, "    frame list does not match td->dma_handle!\n");
-		}
-		show_frame_num();
 
 		head = &td->fl_list;
 		tmp = head;
@@ -467,14 +348,11 @@ static int uhci_sprint_schedule(struct uhci_hcd *uhci, char *buf, int len)
 	out += sprintf(out, "Skeleton QHs\n");
 
 	for (i = 0; i < UHCI_NUM_SKELQH; ++i) {
-		int shown = 0;
+		int cnt = 0;
 
 		qh = uhci->skelqh[i];
-
-		if (debug > 1) {
-			show_qh_name();
-			out += uhci_show_qh(qh, out, len - (out - buf), 4);
-		}
+		out += sprintf(out, "- %s\n", qh_names[i]); \
+		out += uhci_show_qh(qh, out, len - (out - buf), 4);
 
 		/* Last QH is the Terminating QH, it's different */
 		if (i == UHCI_NUM_SKELQH - 1) {
@@ -487,44 +365,27 @@ static int uhci_sprint_schedule(struct uhci_hcd *uhci, char *buf, int len)
 			continue;
 		}
 
-		j = (i < 7) ? 7 : i+1;		/* Next skeleton */
-		if (list_empty(&qh->list)) {
-			if (i < UHCI_NUM_SKELQH - 1) {
-				if (qh->link !=
-				    (cpu_to_le32(uhci->skelqh[j]->dma_handle) | UHCI_PTR_QH)) {
-					show_qh_name();
-					out += sprintf(out, "    skeleton QH not linked to next skeleton QH!\n");
-				}
-			}
-
-			continue;
-		}
-
-		show_qh_name();
-
-		head = &qh->list;
+		j = (i < 9) ? 9 : i+1;		/* Next skeleton */
+		head = &qh->node;
 		tmp = head->next;
 
 		while (tmp != head) {
-			qh = list_entry(tmp, struct uhci_qh, list);
-
+			qh = list_entry(tmp, struct uhci_qh, node);
 			tmp = tmp->next;
-
-			out += uhci_show_qh(qh, out, len - (out - buf), 4);
+			if (++cnt <= 10)
+				out += uhci_show_qh(qh, out,
+						len - (out - buf), 4);
 		}
+		if ((cnt -= 10) > 0)
+			out += sprintf(out, "    Skipped %d QHs\n", cnt);
 
-		if (i < UHCI_NUM_SKELQH - 1) {
+		if (i > 1 && i < UHCI_NUM_SKELQH - 1) {
 			if (qh->link !=
 			    (cpu_to_le32(uhci->skelqh[j]->dma_handle) | UHCI_PTR_QH))
 				out += sprintf(out, "    last QH not linked to next skeleton!\n");
 		}
 	}
 
-	if (debug > 2)
-		out += uhci_show_lists(uhci, out, len - (out - buf));
-
-	spin_unlock_irqrestore(&uhci->lock, flags);
-
 	return out - buf;
 }
 
@@ -541,6 +402,7 @@ static int uhci_debug_open(struct inode *inode, struct file *file)
 	struct uhci_hcd *uhci = inode->u.generic_ip;
 	struct uhci_debug *up;
 	int ret = -ENOMEM;
+	unsigned long flags;
 
 	lock_kernel();
 	up = kmalloc(sizeof(*up), GFP_KERNEL);
@@ -553,7 +415,9 @@ static int uhci_debug_open(struct inode *inode, struct file *file)
 		goto out;
 	}
 
+	spin_lock_irqsave(&uhci->lock, flags);
 	up->size = uhci_sprint_schedule(uhci, up->data, MAX_OUTPUT);
+	spin_unlock_irqrestore(&uhci->lock, flags);
 
 	file->private_data = up;
 

drivers/usb/host/uhci-hcd.c

@@ -54,7 +54,7 @@
 /*
  * Version Information
  */
-#define DRIVER_VERSION "v2.3"
+#define DRIVER_VERSION "v3.0"
 #define DRIVER_AUTHOR "Linus 'Frodo Rabbit' Torvalds, Johannes Erdfelt, \
 Randy Dunlap, Georg Acher, Deti Fliegl, Thomas Sailer, Roman Weissgaerber, \
 Alan Stern"
@@ -489,15 +489,11 @@ static int uhci_start(struct usb_hcd *hcd)
 	uhci->fsbrtimeout = 0;
 
 	spin_lock_init(&uhci->lock);
-	INIT_LIST_HEAD(&uhci->qh_remove_list);
 
 	INIT_LIST_HEAD(&uhci->td_remove_list);
-
-	INIT_LIST_HEAD(&uhci->urb_remove_list);
-
 	INIT_LIST_HEAD(&uhci->urb_list);
-
 	INIT_LIST_HEAD(&uhci->complete_list);
+	INIT_LIST_HEAD(&uhci->idle_qh_list);
 
 	init_waitqueue_head(&uhci->waitqh);
 
@@ -540,7 +536,7 @@ static int uhci_start(struct usb_hcd *hcd)
 	}
 
 	for (i = 0; i < UHCI_NUM_SKELQH; i++) {
-		uhci->skelqh[i] = uhci_alloc_qh(uhci);
+		uhci->skelqh[i] = uhci_alloc_qh(uhci, NULL, NULL);
 		if (!uhci->skelqh[i]) {
 			dev_err(uhci_dev(uhci), "unable to allocate QH\n");
 			goto err_alloc_skelqh;
@@ -557,13 +553,17 @@ static int uhci_start(struct usb_hcd *hcd)
 			uhci->skel_int16_qh->link =
 			uhci->skel_int8_qh->link =
 			uhci->skel_int4_qh->link =
-			uhci->skel_int2_qh->link =
-			cpu_to_le32(uhci->skel_int1_qh->dma_handle) | UHCI_PTR_QH;
-	uhci->skel_int1_qh->link = cpu_to_le32(uhci->skel_ls_control_qh->dma_handle) | UHCI_PTR_QH;
-
-	uhci->skel_ls_control_qh->link = cpu_to_le32(uhci->skel_fs_control_qh->dma_handle) | UHCI_PTR_QH;
-	uhci->skel_fs_control_qh->link = cpu_to_le32(uhci->skel_bulk_qh->dma_handle) | UHCI_PTR_QH;
-	uhci->skel_bulk_qh->link = cpu_to_le32(uhci->skel_term_qh->dma_handle) | UHCI_PTR_QH;
+			uhci->skel_int2_qh->link = UHCI_PTR_QH |
+			cpu_to_le32(uhci->skel_int1_qh->dma_handle);
+
+	uhci->skel_int1_qh->link = UHCI_PTR_QH |
+			cpu_to_le32(uhci->skel_ls_control_qh->dma_handle);
+	uhci->skel_ls_control_qh->link = UHCI_PTR_QH |
+			cpu_to_le32(uhci->skel_fs_control_qh->dma_handle);
+	uhci->skel_fs_control_qh->link = UHCI_PTR_QH |
+			cpu_to_le32(uhci->skel_bulk_qh->dma_handle);
+	uhci->skel_bulk_qh->link = UHCI_PTR_QH |
+			cpu_to_le32(uhci->skel_term_qh->dma_handle);
 
 	/* This dummy TD is to work around a bug in Intel PIIX controllers */
 	uhci_fill_td(uhci->term_td, 0, uhci_explen(0) |
@@ -589,15 +589,15 @@ static int uhci_start(struct usb_hcd *hcd)
 
 		/*
 		 * ffs (Find First bit Set) does exactly what we need:
-		 * 1,3,5,...  => ffs = 0 => use skel_int2_qh = skelqh[6],
-		 * 2,6,10,... => ffs = 1 => use skel_int4_qh = skelqh[5], etc.
-		 * ffs > 6 => not on any high-period queue, so use
-		 *	skel_int1_qh = skelqh[7].
+		 * 1,3,5,...  => ffs = 0 => use skel_int2_qh = skelqh[8],
+		 * 2,6,10,... => ffs = 1 => use skel_int4_qh = skelqh[7], etc.
+		 * ffs >= 7 => not on any high-period queue, so use
+		 *	skel_int1_qh = skelqh[9].
 		 * Add UHCI_NUMFRAMES to insure at least one bit is set.
 		 */
-		irq = 6 - (int) __ffs(i + UHCI_NUMFRAMES);
-		if (irq < 0)
-			irq = 7;
+		irq = 8 - (int) __ffs(i + UHCI_NUMFRAMES);
+		if (irq <= 1)
+			irq = 9;
 
 		/* Only place we don't use the frame list routines */
 		uhci->frame[i] = UHCI_PTR_QH |
@@ -767,13 +767,30 @@ static int uhci_resume(struct usb_hcd *hcd)
 }
 #endif
 
-/* Wait until all the URBs for a particular device/endpoint are gone */
+/* Wait until a particular device/endpoint's QH is idle, and free it */
 static void uhci_hcd_endpoint_disable(struct usb_hcd *hcd,
-		struct usb_host_endpoint *ep)
+		struct usb_host_endpoint *hep)
 {
 	struct uhci_hcd *uhci = hcd_to_uhci(hcd);
+	struct uhci_qh *qh;
+
+	spin_lock_irq(&uhci->lock);
+	qh = (struct uhci_qh *) hep->hcpriv;
+	if (qh == NULL)
+		goto done;
 
-	wait_event_interruptible(uhci->waitqh, list_empty(&ep->urb_list));
+	while (qh->state != QH_STATE_IDLE) {
+		++uhci->num_waiting;
+		spin_unlock_irq(&uhci->lock);
+		wait_event_interruptible(uhci->waitqh,
+				qh->state == QH_STATE_IDLE);
+		spin_lock_irq(&uhci->lock);
+		--uhci->num_waiting;
+	}
+
+	uhci_free_qh(uhci, qh);
+done:
+	spin_unlock_irq(&uhci->lock);
 }
 
 static int uhci_hcd_get_frame_number(struct usb_hcd *hcd)

drivers/usb/host/uhci-hcd.h

@@ -28,8 +28,9 @@
 #define   USBSTS_USBINT		0x0001	/* Interrupt due to IOC */
 #define   USBSTS_ERROR		0x0002	/* Interrupt due to error */
 #define   USBSTS_RD		0x0004	/* Resume Detect */
-#define   USBSTS_HSE		0x0008	/* Host System Error - basically PCI problems */
-#define   USBSTS_HCPE		0x0010	/* Host Controller Process Error - the scripts were buggy */
+#define   USBSTS_HSE		0x0008	/* Host System Error: PCI problems */
+#define   USBSTS_HCPE		0x0010	/* Host Controller Process Error:
+					 * the schedule is buggy */
 #define   USBSTS_HCH		0x0020	/* HC Halted */
 
 /* Interrupt enable register */
@@ -47,7 +48,8 @@
 /* USB port status and control registers */
 #define USBPORTSC1	16
 #define USBPORTSC2	18
-#define   USBPORTSC_CCS		0x0001	/* Current Connect Status ("device present") */
+#define   USBPORTSC_CCS		0x0001	/* Current Connect Status
+					 * ("device present") */
 #define   USBPORTSC_CSC		0x0002	/* Connect Status Change */
 #define   USBPORTSC_PE		0x0004	/* Port Enable */
 #define   USBPORTSC_PEC		0x0008	/* Port Enable Change */
@@ -71,15 +73,16 @@
 #define   USBLEGSUP_RWC		0x8f00	/* the R/WC bits */
 #define   USBLEGSUP_RO		0x5040	/* R/O and reserved bits */
 
-#define UHCI_PTR_BITS		cpu_to_le32(0x000F)
-#define UHCI_PTR_TERM		cpu_to_le32(0x0001)
-#define UHCI_PTR_QH		cpu_to_le32(0x0002)
-#define UHCI_PTR_DEPTH		cpu_to_le32(0x0004)
-#define UHCI_PTR_BREADTH	cpu_to_le32(0x0000)
+#define UHCI_PTR_BITS		__constant_cpu_to_le32(0x000F)
+#define UHCI_PTR_TERM		__constant_cpu_to_le32(0x0001)
+#define UHCI_PTR_QH		__constant_cpu_to_le32(0x0002)
+#define UHCI_PTR_DEPTH		__constant_cpu_to_le32(0x0004)
+#define UHCI_PTR_BREADTH	__constant_cpu_to_le32(0x0000)
 
 #define UHCI_NUMFRAMES		1024	/* in the frame list [array] */
 #define UHCI_MAX_SOF_NUMBER	2047	/* in an SOF packet */
-#define CAN_SCHEDULE_FRAMES	1000	/* how far future frames can be scheduled */
+#define CAN_SCHEDULE_FRAMES	1000	/* how far in the future frames
+					 * can be scheduled */
 
 
 /*
@@ -87,38 +90,54 @@
  */
 
 /*
- * One role of a QH is to hold a queue of TDs for some endpoint.  Each QH is
- * used with one URB, and qh->element (updated by the HC) is either:
- *   - the next unprocessed TD for the URB, or
- *   - UHCI_PTR_TERM (when there's no more traffic for this endpoint), or
- *   - the QH for the next URB queued to the same endpoint.
+ * One role of a QH is to hold a queue of TDs for some endpoint.  One QH goes
+ * with each endpoint, and qh->element (updated by the HC) is either:
+ *   - the next unprocessed TD in the endpoint's queue, or
+ *   - UHCI_PTR_TERM (when there's no more traffic for this endpoint).
  *
  * The other role of a QH is to serve as a "skeleton" framelist entry, so we
  * can easily splice a QH for some endpoint into the schedule at the right
  * place.  Then qh->element is UHCI_PTR_TERM.
  *
- * In the frame list, qh->link maintains a list of QHs seen by the HC:
+ * In the schedule, qh->link maintains a list of QHs seen by the HC:
  *     skel1 --> ep1-qh --> ep2-qh --> ... --> skel2 --> ...
+ *
+ * qh->node is the software equivalent of qh->link.  The differences
+ * are that the software list is doubly-linked and QHs in the UNLINKING
+ * state are on the software list but not the hardware schedule.
+ *
+ * For bookkeeping purposes we maintain QHs even for Isochronous endpoints,
+ * but they never get added to the hardware schedule.
  */
+#define QH_STATE_IDLE		1	/* QH is not being used */
+#define QH_STATE_UNLINKING	2	/* QH has been removed from the
+					 * schedule but the hardware may
+					 * still be using it */
+#define QH_STATE_ACTIVE		3	/* QH is on the schedule */
+
 struct uhci_qh {
 	/* Hardware fields */
-	__le32 link;			/* Next queue */
-	__le32 element;			/* Queue element pointer */
+	__le32 link;			/* Next QH in the schedule */
+	__le32 element;			/* Queue element (TD) pointer */
 
 	/* Software fields */
 	dma_addr_t dma_handle;
 
-	struct urb_priv *urbp;
+	struct list_head node;		/* Node in the list of QHs */
+	struct usb_host_endpoint *hep;	/* Endpoint information */
+	struct usb_device *udev;
+	struct list_head queue;		/* Queue of urbps for this QH */
+	struct uhci_qh *skel;		/* Skeleton for this QH */
 
-	struct list_head list;
-	struct list_head remove_list;
+	unsigned int unlink_frame;	/* When the QH was unlinked */
+	int state;			/* QH_STATE_xxx; see above */
 } __attribute__((aligned(16)));
 
 /*
  * We need a special accessor for the element pointer because it is
  * subject to asynchronous updates by the controller.
  */
-static __le32 inline qh_element(struct uhci_qh *qh) {
+static inline __le32 qh_element(struct uhci_qh *qh) {
 	__le32 element = qh->element;
 
 	barrier();
@@ -149,11 +168,13 @@ static __le32 inline qh_element(struct uhci_qh *qh) {
 #define TD_CTRL_ACTLEN_MASK	0x7FF	/* actual length, encoded as n - 1 */
 
 #define TD_CTRL_ANY_ERROR	(TD_CTRL_STALLED | TD_CTRL_DBUFERR | \
-				 TD_CTRL_BABBLE | TD_CTRL_CRCTIME | TD_CTRL_BITSTUFF)
+				 TD_CTRL_BABBLE | TD_CTRL_CRCTIME | \
+				 TD_CTRL_BITSTUFF)
 
 #define uhci_maxerr(err)		((err) << TD_CTRL_C_ERR_SHIFT)
 #define uhci_status_bits(ctrl_sts)	((ctrl_sts) & 0xF60000)
-#define uhci_actual_length(ctrl_sts)	(((ctrl_sts) + 1) & TD_CTRL_ACTLEN_MASK) /* 1-based */
+#define uhci_actual_length(ctrl_sts)	(((ctrl_sts) + 1) & \
+			TD_CTRL_ACTLEN_MASK)	/* 1-based */
 
 /*
  * for TD <info>: (a.k.a. Token)
@@ -163,7 +184,7 @@ static __le32 inline qh_element(struct uhci_qh *qh) {
 #define TD_TOKEN_TOGGLE_SHIFT	19
 #define TD_TOKEN_TOGGLE		(1 << 19)
 #define TD_TOKEN_EXPLEN_SHIFT	21
-#define TD_TOKEN_EXPLEN_MASK	0x7FF		/* expected length, encoded as n - 1 */
+#define TD_TOKEN_EXPLEN_MASK	0x7FF	/* expected length, encoded as n-1 */
 #define TD_TOKEN_PID_MASK	0xFF
 
 #define uhci_explen(len)	((((len) - 1) & TD_TOKEN_EXPLEN_MASK) << \
@@ -187,7 +208,7 @@ static __le32 inline qh_element(struct uhci_qh *qh) {
  * sw space after the TD entry.
  *
  * td->link points to either another TD (not necessarily for the same urb or
- * even the same endpoint), or nothing (PTR_TERM), or a QH (for queued urbs).
+ * even the same endpoint), or nothing (PTR_TERM), or a QH.
  */
 struct uhci_td {
 	/* Hardware fields */
@@ -210,7 +231,7 @@ struct uhci_td {
  * We need a special accessor for the control/status word because it is
  * subject to asynchronous updates by the controller.
  */
-static u32 inline td_status(struct uhci_td *td) {
+static inline u32 td_status(struct uhci_td *td) {
 	__le32 status = td->status;
 
 	barrier();
@@ -223,17 +244,14 @@ static u32 inline td_status(struct uhci_td *td) {
  */
 
 /*
- * The UHCI driver places Interrupt, Control and Bulk into QHs both
- * to group together TDs for one transfer, and also to facilitate queuing
- * of URBs. To make it easy to insert entries into the schedule, we have
- * a skeleton of QHs for each predefined Interrupt latency, low-speed
- * control, full-speed control and terminating QH (see explanation for
- * the terminating QH below).
+ * The UHCI driver uses QHs with Interrupt, Control and Bulk URBs for
+ * automatic queuing. To make it easy to insert entries into the schedule,
+ * we have a skeleton of QHs for each predefined Interrupt latency,
+ * low-speed control, full-speed control, bulk, and terminating QH
+ * (see explanation for the terminating QH below).
  *
  * When we want to add a new QH, we add it to the end of the list for the
- * skeleton QH.
- *
- * For instance, the queue can look like this:
+ * skeleton QH.  For instance, the schedule list can look like this:
  *
  * skel int128 QH
  * dev 1 interrupt QH
@@ -256,26 +274,31 @@ static u32 inline td_status(struct uhci_td *td) {
  * - To loop back to the full-speed control queue for full-speed bandwidth
  *   reclamation.
  *
- * Isochronous transfers are stored before the start of the skeleton
- * schedule and don't use QHs. While the UHCI spec doesn't forbid the
- * use of QHs for Isochronous, it doesn't use them either. And the spec
- * says that queues never advance on an error completion status, which
- * makes them totally unsuitable for Isochronous transfers.
+ * There's a special skeleton QH for Isochronous QHs.  It never appears
+ * on the schedule, and Isochronous TDs go on the schedule before the
+ * the skeleton QHs.  The hardware accesses them directly rather than
+ * through their QH, which is used only for bookkeeping purposes.
+ * While the UHCI spec doesn't forbid the use of QHs for Isochronous,
+ * it doesn't use them either.  And the spec says that queues never
+ * advance on an error completion status, which makes them totally
+ * unsuitable for Isochronous transfers.
  */
 
-#define UHCI_NUM_SKELQH		12
-#define skel_int128_qh		skelqh[0]
-#define skel_int64_qh		skelqh[1]
-#define skel_int32_qh		skelqh[2]
-#define skel_int16_qh		skelqh[3]
-#define skel_int8_qh		skelqh[4]
-#define skel_int4_qh		skelqh[5]
-#define skel_int2_qh		skelqh[6]
-#define skel_int1_qh		skelqh[7]
-#define skel_ls_control_qh	skelqh[8]
-#define skel_fs_control_qh	skelqh[9]
-#define skel_bulk_qh		skelqh[10]
-#define skel_term_qh		skelqh[11]
+#define UHCI_NUM_SKELQH		14
+#define skel_unlink_qh		skelqh[0]
+#define skel_iso_qh		skelqh[1]
+#define skel_int128_qh		skelqh[2]
+#define skel_int64_qh		skelqh[3]
+#define skel_int32_qh		skelqh[4]
+#define skel_int16_qh		skelqh[5]
+#define skel_int8_qh		skelqh[6]
+#define skel_int4_qh		skelqh[7]
+#define skel_int2_qh		skelqh[8]
+#define skel_int1_qh		skelqh[9]
+#define skel_ls_control_qh	skelqh[10]
+#define skel_fs_control_qh	skelqh[11]
+#define skel_bulk_qh		skelqh[12]
+#define skel_term_qh		skelqh[13]
 
 /*
  * Search tree for determining where <interval> fits in the skelqh[]
@@ -293,21 +316,21 @@ static inline int __interval_to_skel(int interval)
 	if (interval < 16) {
 		if (interval < 4) {
 			if (interval < 2)
-				return 7;	/* int1 for 0-1 ms */
-			return 6;		/* int2 for 2-3 ms */
+				return 9;	/* int1 for 0-1 ms */
+			return 8;		/* int2 for 2-3 ms */
 		}
 		if (interval < 8)
-			return 5;		/* int4 for 4-7 ms */
-		return 4;			/* int8 for 8-15 ms */
+			return 7;		/* int4 for 4-7 ms */
+		return 6;			/* int8 for 8-15 ms */
 	}
 	if (interval < 64) {
 		if (interval < 32)
-			return 3;		/* int16 for 16-31 ms */
-		return 2;			/* int32 for 32-63 ms */
+			return 5;		/* int16 for 16-31 ms */
+		return 4;			/* int32 for 32-63 ms */
 	}
 	if (interval < 128)
-		return 1;			/* int64 for 64-127 ms */
-	return 0;				/* int128 for 128-255 ms (Max.) */
+		return 3;			/* int64 for 64-127 ms */
+	return 2;				/* int128 for 128-255 ms (Max.) */
 }
 
 
@@ -363,12 +386,12 @@ struct uhci_hcd {
 
 	spinlock_t lock;
 
-	dma_addr_t frame_dma_handle;		/* Hardware frame list */
+	dma_addr_t frame_dma_handle;	/* Hardware frame list */
 	__le32 *frame;
-	void **frame_cpu;			/* CPU's frame list */
+	void **frame_cpu;		/* CPU's frame list */
 
-	int fsbr;				/* Full-speed bandwidth reclamation */
-	unsigned long fsbrtimeout;		/* FSBR delay */
+	int fsbr;			/* Full-speed bandwidth reclamation */
+	unsigned long fsbrtimeout;	/* FSBR delay */
 
 	enum uhci_rh_state rh_state;
 	unsigned long auto_stop_time;		/* When to AUTO_STOP */
@@ -392,24 +415,19 @@ struct uhci_hcd {
 	/* Main list of URBs currently controlled by this HC */
 	struct list_head urb_list;
 
-	/* List of QHs that are done, but waiting to be unlinked (race) */
-	struct list_head qh_remove_list;
-	unsigned int qh_remove_age;		/* Age in frames */
-
 	/* List of TDs that are done, but waiting to be freed (race) */
 	struct list_head td_remove_list;
 	unsigned int td_remove_age;		/* Age in frames */
 
-	/* List of asynchronously unlinked URBs */
-	struct list_head urb_remove_list;
-	unsigned int urb_remove_age;		/* Age in frames */
-
 	/* List of URBs awaiting completion callback */
 	struct list_head complete_list;
 
+	struct list_head idle_qh_list;		/* Where the idle QHs live */
+
 	int rh_numports;			/* Number of root-hub ports */
 
 	wait_queue_head_t waitqh;		/* endpoint_disable waiters */
+	int num_waiting;			/* Number of waiters */
 };
 
 /* Convert between a usb_hcd pointer and the corresponding uhci_hcd */
@@ -430,22 +448,19 @@ static inline struct usb_hcd *uhci_to_hcd(struct uhci_hcd *uhci)
  */
 struct urb_priv {
 	struct list_head urb_list;
+	struct list_head node;		/* Node in the QH's urbp list */
 
 	struct urb *urb;
 
 	struct uhci_qh *qh;		/* QH for this URB */
 	struct list_head td_list;
 
-	unsigned fsbr : 1;		/* URB turned on FSBR */
-	unsigned fsbr_timeout : 1;	/* URB timed out on FSBR */
-	unsigned queued : 1;		/* QH was queued (not linked in) */
-	unsigned short_control_packet : 1;	/* If we get a short packet during */
-						/*  a control transfer, retrigger */
-						/*  the status phase */
-
 	unsigned long fsbrtime;		/* In jiffies */
 
-	struct list_head queue_list;
+	unsigned fsbr : 1;		/* URB turned on FSBR */
+	unsigned fsbr_timeout : 1;	/* URB timed out on FSBR */
+	unsigned short_transfer : 1;	/* URB got a short transfer, no
+					 * need to rescan */
 };