[PATCH 07/14] dwc/otg: Add HCD queue function

[Pratyush Anand <pratyush.anand@st.com>]

From: Tirumala Marri <tmarri@apm.com>

Implements functions to manage Queue Heads and Queue
Transfer Descriptors of DWC USB OTG Controller.

Signed-off-by: Tirumala R Marri <tmarri@apm.com>
Signed-off-by: Fushen Chen <fchen@apm.com>
Signed-off-by: Mark Miesfeld <mmiesfeld@apm.com>
---
 drivers/usb/dwc/hcd_queue.c |  696 +++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 696 insertions(+), 0 deletions(-)
 create mode 100644 drivers/usb/dwc/hcd_queue.c

diff --git a/drivers/usb/dwc/hcd_queue.c b/drivers/usb/dwc/hcd_queue.c
new file mode 100644
index 0000000..1f99573
--- /dev/null
+++ b/drivers/usb/dwc/hcd_queue.c
@@ -0,0 +1,696 @@
+/*
+ * DesignWare HS OTG controller driver
+ * Copyright (C) 2006 Synopsys, Inc.
+ * Portions Copyright (C) 2010 Applied Micro Circuits Corporation.
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * 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 version 2 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see http://www.gnu.org/licenses
+ * or write to the Free Software Foundation, Inc., 51 Franklin Street,
+ * Suite 500, Boston, MA 02110-1335 USA.
+ *
+ * Based on Synopsys driver version 2.60a
+ * Modified by Mark Miesfeld <mmiesfeld@apm.com>
+ * Modified by Stefan Roese <sr@denx.de>, DENX Software Engineering
+ * Modified by Chuck Meade <chuck@theptrgroup.com>
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL SYNOPSYS, INC. BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+/*
+ * This file contains the functions to manage Queue Heads and Queue
+ * Transfer Descriptors.
+ */
+
+#include "hcd.h"
+
+static inline int is_fs_ls(enum usb_device_speed speed)
+{
+	return speed == USB_SPEED_FULL || speed == USB_SPEED_LOW;
+}
+
+/* Allocates memory for a QH structure. */
+static inline struct dwc_qh *dwc_otg_hcd_qh_alloc(void)
+{
+	return kmalloc(sizeof(struct dwc_qh), GFP_ATOMIC);
+}
+
+/**
+ * Initializes a QH structure to initialize the QH.
+ */
+#define SCHEDULE_SLOP 10
+static void dwc_otg_hcd_qh_init(struct dwc_hcd *hcd, struct dwc_qh *qh,
+				struct urb *urb)
+{
+	memset(qh, 0, sizeof(struct dwc_qh));
+
+	/* Initialize QH */
+	switch (usb_pipetype(urb->pipe)) {
+	case PIPE_CONTROL:
+		qh->ep_type = USB_ENDPOINT_XFER_CONTROL;
+		break;
+	case PIPE_BULK:
+		qh->ep_type = USB_ENDPOINT_XFER_BULK;
+		break;
+	case PIPE_ISOCHRONOUS:
+		qh->ep_type = USB_ENDPOINT_XFER_ISOC;
+		break;
+	case PIPE_INTERRUPT:
+		qh->ep_type = USB_ENDPOINT_XFER_INT;
+		break;
+	}
+
+	qh->ep_is_in = usb_pipein(urb->pipe) ? 1 : 0;
+	qh->data_toggle = DWC_OTG_HC_PID_DATA0;
+	qh->maxp = usb_maxpacket(urb->dev, urb->pipe, !(usb_pipein(urb->pipe)));
+
+	INIT_LIST_HEAD(&qh->qtd_list);
+	INIT_LIST_HEAD(&qh->qh_list_entry);
+
+	qh->channel = NULL;
+	qh->speed = urb->dev->speed;
+
+	/*
+	 * FS/LS Enpoint on HS Hub NOT virtual root hub
+	 */
+	qh->do_split = 0;
+	if (is_fs_ls(urb->dev->speed) && urb->dev->tt && urb->dev->tt->hub &&
+	    urb->dev->tt->hub->devnum != 1)
+		qh->do_split = 1;
+
+	if (qh->ep_type == USB_ENDPOINT_XFER_INT ||
+	    qh->ep_type == USB_ENDPOINT_XFER_ISOC) {
+		/* Compute scheduling parameters once and save them. */
+		u32 hprt;
+		int bytecount = dwc_hb_mult(qh->maxp) *
+		    dwc_max_packet(qh->maxp);
+
+		qh->usecs = NS_TO_US(usb_calc_bus_time(urb->dev->speed,
+						       usb_pipein(urb->pipe),
+						       (qh->ep_type ==
+							USB_ENDPOINT_XFER_ISOC),
+						       bytecount));
+
+		/* Start in a slightly future (micro)frame. */
+		qh->sched_frame = dwc_frame_num_inc(hcd->frame_number,
+						    SCHEDULE_SLOP);
+		qh->interval = urb->interval;
+
+		hprt = dwc_read32(hcd->core_if->host_if->hprt0);
+		if (DWC_HPRT0_PRT_SPD_RD(hprt) == DWC_HPRT0_PRTSPD_HIGH_SPEED &&
+		    is_fs_ls(urb->dev->speed)) {
+			qh->interval *= 8;
+			qh->sched_frame |= 0x7;
+			qh->start_split_frame = qh->sched_frame;
+		}
+	}
+}
+
+/**
+ * This function allocates and initializes a QH.
+ */
+static struct dwc_qh *dwc_otg_hcd_qh_create(struct dwc_hcd *hcd,
+					    struct urb *urb)
+{
+	struct dwc_qh *qh;
+
+	/* Allocate memory */
+	qh = dwc_otg_hcd_qh_alloc();
+	if (qh == NULL)
+		return NULL;
+
+	dwc_otg_hcd_qh_init(hcd, qh, urb);
+	return qh;
+}
+
+/**
+ * Free each QTD in the QH's QTD-list then free the QH.  QH should already be
+ * removed from a list.  QTD list should already be empty if called from URB
+ * Dequeue.
+ */
+void dwc_otg_hcd_qh_free(struct dwc_qh *qh)
+{
+	struct dwc_qtd *qtd;
+	struct list_head *pos, *temp;
+
+	/* Free each QTD in the QTD list */
+	list_for_each_safe(pos, temp, &qh->qtd_list) {
+		list_del(pos);
+		qtd = dwc_list_to_qtd(pos);
+		dwc_otg_hcd_qtd_free(qtd);
+	}
+	kfree(qh);
+}
+
+/**
+ * Microframe scheduler
+ * track the total use in hcd->frame_usecs
+ * keep each qh use in qh->frame_usecs
+ * when surrendering the qh then donate the time back
+ */
+static const u16 max_uframe_usecs[] = { 100, 100, 100, 100, 100, 100, 30, 0 };
+
+/*
+ * called from dwc_otg_hcd.c:dwc_otg_hcd_init
+ */
+int init_hcd_usecs(struct dwc_hcd *hcd)
+{
+	int i;
+
+	for (i = 0; i < 8; i++)
+		hcd->frame_usecs[i] = max_uframe_usecs[i];
+
+	return 0;
+}
+
+static int find_single_uframe(struct dwc_hcd *hcd, struct dwc_qh *qh)
+{
+	int i;
+	u16 utime;
+	int t_left;
+	int ret;
+	int done;
+
+	ret = -1;
+	utime = qh->usecs;
+	t_left = utime;
+	i = 0;
+	done = 0;
+	while (done == 0) {
+		/* At the start hcd->frame_usecs[i] = max_uframe_usecs[i]; */
+		if (utime <= hcd->frame_usecs[i]) {
+			hcd->frame_usecs[i] -= utime;
+			qh->frame_usecs[i] += utime;
+			t_left -= utime;
+			ret = i;
+			done = 1;
+			return ret;
+		} else {
+			i++;
+			if (i == 8) {
+				done = 1;
+				ret = -1;
+			}
+		}
+	}
+	return ret;
+}
+
+/*
+ * use this for FS apps that can span multiple uframes
+ */
+static int find_multi_uframe(struct dwc_hcd *hcd, struct dwc_qh *qh)
+{
+	int i;
+	int j;
+	u16 utime;
+	int t_left;
+	int ret;
+	int done;
+	u16 xtime;
+
+	ret = -1;
+	utime = qh->usecs;
+	t_left = utime;
+	i = 0;
+	done = 0;
+loop:
+	while (done == 0) {
+		if (hcd->frame_usecs[i] <= 0) {
+			i++;
+			if (i == 8) {
+				done = 1;
+				ret = -1;
+			}
+			goto loop;
+		}
+
+		/*
+		 * We need n consequtive slots so use j as a start slot.
+		 * j plus j+1 must be enough time (for now)
+		 */
+		xtime = hcd->frame_usecs[i];
+		for (j = i + 1; j < 8; j++) {
+			/*
+			 * if we add this frame remaining time to xtime we may
+			 * be OK, if not we need to test j for a complete frame.
+			 */
+			if ((xtime + hcd->frame_usecs[j]) < utime) {
+				if (hcd->frame_usecs[j] < max_uframe_usecs[j]) {
+					j = 8;
+					ret = -1;
+					continue;
+				}
+			}
+			if (xtime >= utime) {
+				ret = i;
+				j = 8;	/* stop loop with a good value ret */
+				continue;
+			}
+			/* add the frame time to x time */
+			xtime += hcd->frame_usecs[j];
+			/* we must have a fully available next frame or break */
+			if ((xtime < utime) &&
+			    (hcd->frame_usecs[j] == max_uframe_usecs[j])) {
+				ret = -1;
+				j = 8;	/* stop loop with a bad value ret */
+				continue;
+			}
+		}
+		if (ret >= 0) {
+			t_left = utime;
+			for (j = i; (t_left > 0) && (j < 8); j++) {
+				t_left -= hcd->frame_usecs[j];
+				if (t_left <= 0) {
+					qh->frame_usecs[j] +=
+					    hcd->frame_usecs[j] + t_left;
+					hcd->frame_usecs[j] = -t_left;
+					ret = i;
+					done = 1;
+				} else {
+					qh->frame_usecs[j] +=
+					    hcd->frame_usecs[j];
+					hcd->frame_usecs[j] = 0;
+				}
+			}
+		} else {
+			i++;
+			if (i == 8) {
+				done = 1;
+				ret = -1;
+			}
+		}
+	}
+	return ret;
+}
+
+static int find_uframe(struct dwc_hcd *hcd, struct dwc_qh *qh)
+{
+	int ret = -1;
+
+	if (qh->speed == USB_SPEED_HIGH)
+		/* if this is a hs transaction we need a full frame */
+		ret = find_single_uframe(hcd, qh);
+	else
+		/* FS transaction may need a sequence of frames */
+		ret = find_multi_uframe(hcd, qh);
+
+	return ret;
+}
+
+/**
+ * Checks that the max transfer size allowed in a host channel is large enough
+ * to handle the maximum data transfer in a single (micro)frame for a periodic
+ * transfer.
+ */
+static int check_max_xfer_size(struct dwc_hcd *hcd, struct dwc_qh *qh)
+{
+	int status = 0;
+	u32 max_xfer_size;
+	u32 max_channel_xfer_size;
+
+	max_xfer_size = dwc_max_packet(qh->maxp) * dwc_hb_mult(qh->maxp);
+	max_channel_xfer_size = hcd->core_if->core_params->max_transfer_size;
+
+	if (max_xfer_size > max_channel_xfer_size) {
+		pr_notice("%s: Periodic xfer length %d > max xfer "
+			  "length for channel %d\n", __func__, max_xfer_size,
+			  max_channel_xfer_size);
+		status = -ENOSPC;
+	}
+
+	return status;
+}
+
+/**
+ * Schedules an interrupt or isochronous transfer in the periodic schedule.
+ */
+static int schedule_periodic(struct dwc_hcd *hcd, struct dwc_qh *qh)
+{
+	int status;
+	struct usb_bus *bus = hcd_to_bus(dwc_otg_hcd_to_hcd(hcd));
+	int frame;
+
+	status = find_uframe(hcd, qh);
+	frame = -1;
+	if (status == 0) {
+		frame = 7;
+	} else {
+		if (status > 0)
+			frame = status - 1;
+	}
+	/* Set the new frame up */
+	if (frame > -1) {
+		qh->sched_frame &= ~0x7;
+		qh->sched_frame |= (frame & 7);
+	}
+	if (status != -1)
+		status = 0;
+	if (status) {
+		pr_notice("%s: Insufficient periodic bandwidth for "
+			  "periodic transfer.\n", __func__);
+		return status;
+	}
+	status = check_max_xfer_size(hcd, qh);
+	if (status) {
+		pr_notice("%s: Channel max transfer size too small "
+			  "for periodic transfer.\n", __func__);
+		return status;
+	}
+	/* Always start in the inactive schedule. */
+	list_add_tail(&qh->qh_list_entry, &hcd->periodic_sched_inactive);
+
+	/* Update claimed usecs per (micro)frame. */
+	hcd->periodic_usecs += qh->usecs;
+
+	/*
+	 * Update average periodic bandwidth claimed and # periodic reqs for
+	 * usbfs.
+	 */
+	bus->bandwidth_allocated += qh->usecs / qh->interval;
+
+	if (qh->ep_type == USB_ENDPOINT_XFER_INT)
+		bus->bandwidth_int_reqs++;
+	else
+		bus->bandwidth_isoc_reqs++;
+
+	return status;
+}
+
+/**
+ * This function adds a QH to either the non periodic or periodic schedule if
+ * it is not already in the schedule. If the QH is already in the schedule, no
+ * action is taken.
+ */
+static int dwc_otg_hcd_qh_add(struct dwc_hcd *hcd, struct dwc_qh *qh)
+{
+	int status = 0;
+
+	/* QH may already be in a schedule. */
+	if (!list_empty(&qh->qh_list_entry))
+		goto done;
+	/*
+	 * Add the new QH to the appropriate schedule. For non-periodic, always
+	 * start in the inactive schedule.
+	 */
+	if (dwc_qh_is_non_per(qh))
+		list_add_tail(&qh->qh_list_entry,
+			      &hcd->non_periodic_sched_inactive);
+	else
+		status = schedule_periodic(hcd, qh);
+
+done:
+	return status;
+}
+
+/**
+ * This function adds a QH to the non periodic deferred schedule.
+ *
+ * @return 0 if successful, negative error code otherwise.
+ */
+static int dwc_otg_hcd_qh_add_deferred(struct dwc_hcd *hcd, struct dwc_qh *qh)
+{
+	if (!list_empty(&qh->qh_list_entry))
+		/* QH already in a schedule. */
+		goto done;
+
+	/* Add the new QH to the non periodic deferred schedule */
+	if (dwc_qh_is_non_per(qh))
+		list_add_tail(&qh->qh_list_entry,
+			      &hcd->non_periodic_sched_deferred);
+done:
+	return 0;
+}
+
+/**
+ * Removes an interrupt or isochronous transfer from the periodic schedule.
+ */
+static void deschedule_periodic(struct dwc_hcd *hcd, struct dwc_qh *qh)
+{
+	struct usb_bus *bus = hcd_to_bus(dwc_otg_hcd_to_hcd(hcd));
+	int i;
+
+	list_del_init(&qh->qh_list_entry);
+	/* Update claimed usecs per (micro)frame. */
+	hcd->periodic_usecs -= qh->usecs;
+	for (i = 0; i < 8; i++) {
+		hcd->frame_usecs[i] += qh->frame_usecs[i];
+		qh->frame_usecs[i] = 0;
+	}
+	/*
+	 * Update average periodic bandwidth claimed and # periodic reqs for
+	 * usbfs.
+	 */
+	bus->bandwidth_allocated -= qh->usecs / qh->interval;
+
+	if (qh->ep_type == USB_ENDPOINT_XFER_INT)
+		bus->bandwidth_int_reqs--;
+	else
+		bus->bandwidth_isoc_reqs--;
+}
+
+/**
+ * Removes a QH from either the non-periodic or periodic schedule.  Memory is
+ * not freed.
+ */
+void dwc_otg_hcd_qh_remove(struct dwc_hcd *hcd, struct dwc_qh *qh)
+{
+	/* Do nothing if QH is not in a schedule */
+	if (list_empty(&qh->qh_list_entry))
+		return;
+
+	if (dwc_qh_is_non_per(qh)) {
+		if (hcd->non_periodic_qh_ptr == &qh->qh_list_entry)
+			hcd->non_periodic_qh_ptr =
+			    hcd->non_periodic_qh_ptr->next;
+		list_del_init(&qh->qh_list_entry);
+	} else {
+		deschedule_periodic(hcd, qh);
+	}
+}
+
+/**
+ * Defers a QH. For non-periodic QHs, removes the QH from the active
+ * non-periodic schedule. The QH is added to the deferred non-periodic
+ * schedule if any QTDs are still attached to the QH.
+ */
+int dwc_otg_hcd_qh_deferr(struct dwc_hcd *hcd, struct dwc_qh *qh, int delay)
+{
+	int deact = 1;
+
+	if (dwc_qh_is_non_per(qh)) {
+		qh->sched_frame = dwc_frame_num_inc(hcd->frame_number, delay);
+		qh->channel = NULL;
+		qh->qtd_in_process = NULL;
+		deact = 0;
+		dwc_otg_hcd_qh_remove(hcd, qh);
+		if (!list_empty(&qh->qtd_list))
+			/* Add back to deferred non-periodic schedule. */
+			dwc_otg_hcd_qh_add_deferred(hcd, qh);
+	}
+	return deact;
+}
+
+/**
+ *  Schedule the next continuing periodic split transfer
+ */
+static void sched_next_per_split_xfr(struct dwc_qh *qh, u16 fr_num,
+				     int sched_split)
+{
+	if (sched_split) {
+		qh->sched_frame = fr_num;
+		if (dwc_frame_num_le(fr_num,
+				     dwc_frame_num_inc(qh->start_split_frame,
+						       1))) {
+			/*
+			 * Allow one frame to elapse after start split
+			 * microframe before scheduling complete split, but DONT
+			 * if we are doing the next start split in the
+			 * same frame for an ISOC out.
+			 */
+			if (qh->ep_type != USB_ENDPOINT_XFER_ISOC ||
+			    qh->ep_is_in)
+				qh->sched_frame =
+				    dwc_frame_num_inc(qh->sched_frame, 1);
+		}
+	} else {
+		qh->sched_frame = dwc_frame_num_inc(qh->start_split_frame,
+						    qh->interval);
+
+		if (dwc_frame_num_le(qh->sched_frame, fr_num))
+			qh->sched_frame = fr_num;
+		qh->sched_frame |= 0x7;
+		qh->start_split_frame = qh->sched_frame;
+	}
+}
+
+/**
+ * Deactivates a periodic QH.  The QH is removed from the periodic queued
+ * schedule. If there are any QTDs still attached to the QH, the QH is added to
+ * either the periodic inactive schedule or the periodic ready schedule and its
+ * next scheduled frame is calculated. The QH is placed in the ready schedule if
+ * the scheduled frame has been reached already. Otherwise it's placed in the
+ * inactive schedule. If there are no QTDs attached to the QH, the QH is
+ * completely removed from the periodic schedule.
+ */
+static void deactivate_periodic_qh(struct dwc_hcd *hcd, struct dwc_qh *qh,
+				   int sched_next_split)
+{
+	/* unsigned long flags; */
+	u16 fr_num = dwc_otg_hcd_get_frame_number(dwc_otg_hcd_to_hcd(hcd));
+
+	if (qh->do_split) {
+		sched_next_per_split_xfr(qh, fr_num, sched_next_split);
+	} else {
+		qh->sched_frame = dwc_frame_num_inc(qh->sched_frame,
+						    qh->interval);
+		if (dwc_frame_num_le(qh->sched_frame, fr_num))
+			qh->sched_frame = fr_num;
+	}
+
+	if (list_empty(&qh->qtd_list)) {
+		dwc_otg_hcd_qh_remove(hcd, qh);
+	} else {
+		/*
+		 * Remove from periodic_sched_queued and move to appropriate
+		 * queue.
+		 */
+		if (qh->sched_frame == fr_num)
+			list_move(&qh->qh_list_entry,
+				  &hcd->periodic_sched_ready);
+		else
+			list_move(&qh->qh_list_entry,
+				  &hcd->periodic_sched_inactive);
+	}
+}
+
+/**
+ * Deactivates a non-periodic QH.  Removes the QH from the active non-periodic
+ * schedule. The QH is added to the inactive non-periodic schedule if any QTDs
+ * are still attached to the QH.
+ */
+static void deactivate_non_periodic_qh(struct dwc_hcd *hcd, struct dwc_qh *qh)
+{
+	dwc_otg_hcd_qh_remove(hcd, qh);
+	if (!list_empty(&qh->qtd_list))
+		dwc_otg_hcd_qh_add(hcd, qh);
+}
+
+/**
+ * Deactivates a QH.  Determines if the QH is periodic or non-periodic and takes
+ * the appropriate action.
+ */
+void dwc_otg_hcd_qh_deactivate(struct dwc_hcd *hcd, struct dwc_qh *qh,
+			       int sched_next_periodic_split)
+{
+	if (dwc_qh_is_non_per(qh))
+		deactivate_non_periodic_qh(hcd, qh);
+	else
+		deactivate_periodic_qh(hcd, qh, sched_next_periodic_split);
+}
+
+/**
+ * Initializes a QTD structure.
+ */
+static void dwc_otg_hcd_qtd_init(struct dwc_qtd *qtd, struct urb *urb)
+{
+	memset(qtd, 0, sizeof(struct dwc_qtd));
+	qtd->urb = urb;
+
+	if (usb_pipecontrol(urb->pipe)) {
+		/*
+		 * The only time the QTD data toggle is used is on the data
+		 * phase of control transfers. This phase always starts with
+		 * DATA1.
+		 */
+		qtd->data_toggle = DWC_OTG_HC_PID_DATA1;
+		qtd->control_phase = DWC_OTG_CONTROL_SETUP;
+	}
+
+	/* start split */
+	qtd->complete_split = 0;
+	qtd->isoc_split_pos = DWC_HCSPLIT_XACTPOS_ALL;
+	qtd->isoc_split_offset = 0;
+
+	/* Store the qtd ptr in the urb to reference what QTD. */
+	urb->hcpriv = qtd;
+
+	INIT_LIST_HEAD(&qtd->qtd_list_entry);
+	return;
+}
+
+/* Allocates memory for a QTD structure. */
+static inline struct dwc_qtd *dwc_otg_hcd_qtd_alloc(gfp_t _mem_flags)
+{
+	return kmalloc(sizeof(struct dwc_qtd), _mem_flags);
+}
+
+/**
+ * This function allocates and initializes a QTD.
+ */
+struct dwc_qtd *dwc_otg_hcd_qtd_create(struct urb *urb, gfp_t _mem_flags)
+{
+	struct dwc_qtd *qtd = dwc_otg_hcd_qtd_alloc(_mem_flags);
+
+	if (!qtd)
+		return NULL;
+
+	dwc_otg_hcd_qtd_init(qtd, urb);
+	return qtd;
+}
+
+/**
+ * This function adds a QTD to the QTD-list of a QH.  It will find the correct
+ * QH to place the QTD into.  If it does not find a QH, then it will create a
+ * new QH. If the QH to which the QTD is added is not currently scheduled, it
+ * is placed into the proper schedule based on its EP type.
+ *
+ */
+int dwc_otg_hcd_qtd_add(struct dwc_qtd *qtd, struct dwc_hcd *hcd)
+{
+	struct usb_host_endpoint *ep;
+	struct dwc_qh *qh;
+	int retval = 0;
+	struct urb *urb = qtd->urb;
+
+	/*
+	 * Get the QH which holds the QTD-list to insert to. Create QH if it
+	 * doesn't exist.
+	 */
+	ep = dwc_urb_to_endpoint(urb);
+
+	qh = (struct dwc_qh *)ep->hcpriv;
+	if (!qh) {
+		qh = dwc_otg_hcd_qh_create(hcd, urb);
+		if (!qh) {
+			retval = -1;
+			goto done;
+		}
+		ep->hcpriv = qh;
+	}
+	qtd->qtd_qh_ptr = qh;
+	retval = dwc_otg_hcd_qh_add(hcd, qh);
+	if (!retval)
+		list_add_tail(&qtd->qtd_list_entry, &qh->qtd_list);
+
+done:
+	return retval;
+}
-- 
1.7.2.2