drivers/usb/host/whci/pzl.c - kernel/msm-4.9 - Gitiles

 /*
  * Wireless Host Controller (WHC) periodic schedule management.
  *
  * Copyright (C) 2007 Cambridge Silicon Radio Ltd.
  *
  * 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 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/>.
  */
 #include <linux/kernel.h>
 #include <linux/gfp.h>
 #include <linux/dma-mapping.h>
 #include <linux/uwb/umc.h>
 #include <linux/usb.h>

 #include "../../wusbcore/wusbhc.h"

 #include "whcd.h"

 static void update_pzl_pointers(struct whc *whc, int period, u64 addr)
 {
 	switch (period) {
 	case 0:
 		whc_qset_set_link_ptr(&whc->pz_list[0], addr);
 		whc_qset_set_link_ptr(&whc->pz_list[2], addr);
 		whc_qset_set_link_ptr(&whc->pz_list[4], addr);
 		whc_qset_set_link_ptr(&whc->pz_list[6], addr);
 		whc_qset_set_link_ptr(&whc->pz_list[8], addr);
 		whc_qset_set_link_ptr(&whc->pz_list[10], addr);
 		whc_qset_set_link_ptr(&whc->pz_list[12], addr);
 		whc_qset_set_link_ptr(&whc->pz_list[14], addr);
 		break;
 	case 1:
 		whc_qset_set_link_ptr(&whc->pz_list[1], addr);
 		whc_qset_set_link_ptr(&whc->pz_list[5], addr);
 		whc_qset_set_link_ptr(&whc->pz_list[9], addr);
 		whc_qset_set_link_ptr(&whc->pz_list[13], addr);
 		break;
 	case 2:
 		whc_qset_set_link_ptr(&whc->pz_list[3], addr);
 		whc_qset_set_link_ptr(&whc->pz_list[11], addr);
 		break;
 	case 3:
 		whc_qset_set_link_ptr(&whc->pz_list[7], addr);
 		break;
 	case 4:
 		whc_qset_set_link_ptr(&whc->pz_list[15], addr);
 		break;
 	}
 }

 /*
  * Return the 'period' to use for this qset.  The minimum interval for
  * the endpoint is used so whatever urbs are submitted the device is
  * polled often enough.
  */
 static int qset_get_period(struct whc *whc, struct whc_qset *qset)
 {
 	uint8_t bInterval = qset->ep->desc.bInterval;

 	if (bInterval < 6)
 		bInterval = 6;
 	if (bInterval > 10)
 		bInterval = 10;
 	return bInterval - 6;
 }

 static void qset_insert_in_sw_list(struct whc *whc, struct whc_qset *qset)
 {
 	int period;

 	period = qset_get_period(whc, qset);

 	qset_clear(whc, qset);
 	list_move(&qset->list_node, &whc->periodic_list[period]);
 	qset->in_sw_list = true;
 }

 static void pzl_qset_remove(struct whc *whc, struct whc_qset *qset)
 {
 	list_move(&qset->list_node, &whc->periodic_removed_list);
 	qset->in_hw_list = false;
 	qset->in_sw_list = false;
 }

 /**
  * pzl_process_qset - process any recently inactivated or halted qTDs
  * in a qset.
  *
  * After inactive qTDs are removed, new qTDs can be added if the
  * urb queue still contains URBs.
  *
  * Returns the schedule updates required.
  */
 static enum whc_update pzl_process_qset(struct whc *whc, struct whc_qset *qset)
 {
 	enum whc_update update = 0;
 	uint32_t status = 0;

 	while (qset->ntds) {
 		struct whc_qtd *td;
 		int t;

 		t = qset->td_start;
 		td = &qset->qtd[qset->td_start];
 		status = le32_to_cpu(td->status);

 		/*
 		 * Nothing to do with a still active qTD.
 		 */
 		if (status & QTD_STS_ACTIVE)
 			break;

 		if (status & QTD_STS_HALTED) {
 			/* Ug, an error. */
 			process_halted_qtd(whc, qset, td);
 			/* A halted qTD always triggers an update
 			   because the qset was either removed or
 			   reactivated. */
 			update |= WHC_UPDATE_UPDATED;
 			goto done;
 		}

 		/* Mmm, a completed qTD. */
 		process_inactive_qtd(whc, qset, td);
 	}

 	if (!qset->remove)
 		update |= qset_add_qtds(whc, qset);

 done:
 	/*
 	 * If there are no qTDs in this qset, remove it from the PZL.
 	 */
 	if (qset->remove && qset->ntds == 0) {
 		pzl_qset_remove(whc, qset);
 		update |= WHC_UPDATE_REMOVED;
 	}

 	return update;
 }

 /**
  * pzl_start - start the periodic schedule
  * @whc: the WHCI host controller
  *
  * The PZL must be valid (e.g., all entries in the list should have
  * the T bit set).
  */
 void pzl_start(struct whc *whc)
 {
 	le_writeq(whc->pz_list_dma, whc->base + WUSBPERIODICLISTBASE);

 	whc_write_wusbcmd(whc, WUSBCMD_PERIODIC_EN, WUSBCMD_PERIODIC_EN);
 	whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
 		      WUSBSTS_PERIODIC_SCHED, WUSBSTS_PERIODIC_SCHED,
 		      1000, "start PZL");
 }

 /**
  * pzl_stop - stop the periodic schedule
  * @whc: the WHCI host controller
  */
 void pzl_stop(struct whc *whc)
 {
 	whc_write_wusbcmd(whc, WUSBCMD_PERIODIC_EN, 0);
 	whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
 		      WUSBSTS_PERIODIC_SCHED, 0,
 		      1000, "stop PZL");
 }

 /**
  * pzl_update - request a PZL update and wait for the hardware to be synced
  * @whc: the WHCI HC
  * @wusbcmd: WUSBCMD value to start the update.
  *
  * If the WUSB HC is inactive (i.e., the PZL is stopped) then the
  * update must be skipped as the hardware may not respond to update
  * requests.
  */
 void pzl_update(struct whc *whc, uint32_t wusbcmd)
 {
 	struct wusbhc *wusbhc = &whc->wusbhc;
 	long t;

 	mutex_lock(&wusbhc->mutex);
 	if (wusbhc->active) {
 		whc_write_wusbcmd(whc, wusbcmd, wusbcmd);
 		t = wait_event_timeout(
 			whc->periodic_list_wq,
 			(le_readl(whc->base + WUSBCMD) & WUSBCMD_PERIODIC_UPDATED) == 0,
 			msecs_to_jiffies(1000));
 		if (t == 0)
 			whc_hw_error(whc, "PZL update timeout");
 	}
 	mutex_unlock(&wusbhc->mutex);
 }

 static void update_pzl_hw_view(struct whc *whc)
 {
 	struct whc_qset *qset, *t;
 	int period;
 	u64 tmp_qh = 0;

 	for (period = 0; period < 5; period++) {
 		list_for_each_entry_safe(qset, t, &whc->periodic_list[period], list_node) {
 			whc_qset_set_link_ptr(&qset->qh.link, tmp_qh);
 			tmp_qh = qset->qset_dma;
 			qset->in_hw_list = true;
 		}
 		update_pzl_pointers(whc, period, tmp_qh);
 	}
 }

 /**
  * scan_periodic_work - scan the PZL for qsets to process.
  *
  * Process each qset in the PZL in turn and then signal the WHC that
  * the PZL has been updated.
  *
  * Then start, stop or update the periodic schedule as required.
  */
 void scan_periodic_work(struct work_struct *work)
 {
 	struct whc *whc = container_of(work, struct whc, periodic_work);
 	struct whc_qset *qset, *t;
 	enum whc_update update = 0;
 	int period;

 	spin_lock_irq(&whc->lock);

 	for (period = 4; period >= 0; period--) {
 		list_for_each_entry_safe(qset, t, &whc->periodic_list[period], list_node) {
 			if (!qset->in_hw_list)
 				update |= WHC_UPDATE_ADDED;
 			update |= pzl_process_qset(whc, qset);
 		}
 	}

 	if (update & (WHC_UPDATE_ADDED | WHC_UPDATE_REMOVED))
 		update_pzl_hw_view(whc);

 	spin_unlock_irq(&whc->lock);

 	if (update) {
 		uint32_t wusbcmd = WUSBCMD_PERIODIC_UPDATED | WUSBCMD_PERIODIC_SYNCED_DB;
 		if (update & WHC_UPDATE_REMOVED)
 			wusbcmd |= WUSBCMD_PERIODIC_QSET_RM;
 		pzl_update(whc, wusbcmd);
 	}

 	/*
 	 * Now that the PZL is updated, complete the removal of any
 	 * removed qsets.
 	 *
 	 * If the qset was to be reset, do so and reinsert it into the
 	 * PZL if it has pending transfers.
 	 */
 	spin_lock_irq(&whc->lock);

 	list_for_each_entry_safe(qset, t, &whc->periodic_removed_list, list_node) {
 		qset_remove_complete(whc, qset);
 		if (qset->reset) {
 			qset_reset(whc, qset);
 			if (!list_empty(&qset->stds)) {
 				qset_insert_in_sw_list(whc, qset);
 				queue_work(whc->workqueue, &whc->periodic_work);
 			}
 		}
 	}

 	spin_unlock_irq(&whc->lock);
 }

 /**
  * pzl_urb_enqueue - queue an URB onto the periodic list (PZL)
  * @whc: the WHCI host controller
  * @urb: the URB to enqueue
  * @mem_flags: flags for any memory allocations
  *
  * The qset for the endpoint is obtained and the urb queued on to it.
  *
  * Work is scheduled to update the hardware's view of the PZL.
  */
 int pzl_urb_enqueue(struct whc *whc, struct urb *urb, gfp_t mem_flags)
 {
 	struct whc_qset *qset;
 	int err;
 	unsigned long flags;

 	spin_lock_irqsave(&whc->lock, flags);

 	err = usb_hcd_link_urb_to_ep(&whc->wusbhc.usb_hcd, urb);
 	if (err < 0) {
 		spin_unlock_irqrestore(&whc->lock, flags);
 		return err;
 	}

 	qset = get_qset(whc, urb, GFP_ATOMIC);
 	if (qset == NULL)
 		err = -ENOMEM;
 	else
 		err = qset_add_urb(whc, qset, urb, GFP_ATOMIC);
 	if (!err) {
 		if (!qset->in_sw_list && !qset->remove)
 			qset_insert_in_sw_list(whc, qset);
 	} else
 		usb_hcd_unlink_urb_from_ep(&whc->wusbhc.usb_hcd, urb);

 	spin_unlock_irqrestore(&whc->lock, flags);

 	if (!err)
 		queue_work(whc->workqueue, &whc->periodic_work);

 	return err;
 }

 /**
  * pzl_urb_dequeue - remove an URB (qset) from the periodic list
  * @whc: the WHCI host controller
  * @urb: the URB to dequeue
  * @status: the current status of the URB
  *
  * URBs that do yet have qTDs can simply be removed from the software
  * queue, otherwise the qset must be removed so the qTDs can be safely
  * removed.
  */
 int pzl_urb_dequeue(struct whc *whc, struct urb *urb, int status)
 {
 	struct whc_urb *wurb = urb->hcpriv;
 	struct whc_qset *qset = wurb->qset;
 	struct whc_std *std, *t;
 	bool has_qtd = false;
 	int ret;
 	unsigned long flags;

 	spin_lock_irqsave(&whc->lock, flags);

 	ret = usb_hcd_check_unlink_urb(&whc->wusbhc.usb_hcd, urb, status);
 	if (ret < 0)
 		goto out;

 	list_for_each_entry_safe(std, t, &qset->stds, list_node) {
 		if (std->urb == urb) {
 			if (std->qtd)
 				has_qtd = true;
 			qset_free_std(whc, std);
 		} else
 			std->qtd = NULL; /* so this std is re-added when the qset is */
 	}

 	if (has_qtd) {
 		pzl_qset_remove(whc, qset);
 		update_pzl_hw_view(whc);
 		wurb->status = status;
 		wurb->is_async = false;
 		queue_work(whc->workqueue, &wurb->dequeue_work);
 	} else
 		qset_remove_urb(whc, qset, urb, status);
 out:
 	spin_unlock_irqrestore(&whc->lock, flags);

 	return ret;
 }

 /**
  * pzl_qset_delete - delete a qset from the PZL
  */
 void pzl_qset_delete(struct whc *whc, struct whc_qset *qset)
 {
 	qset->remove = 1;
 	queue_work(whc->workqueue, &whc->periodic_work);
 	qset_delete(whc, qset);
 }

 /**
  * pzl_init - initialize the periodic zone list
  * @whc: the WHCI host controller
  */
 int pzl_init(struct whc *whc)
 {
 	int i;

 	whc->pz_list = dma_alloc_coherent(&whc->umc->dev, sizeof(u64) * 16,
 					  &whc->pz_list_dma, GFP_KERNEL);
 	if (whc->pz_list == NULL)
 		return -ENOMEM;

 	/* Set T bit on all elements in PZL. */
 	for (i = 0; i < 16; i++)
 		whc->pz_list[i] = cpu_to_le64(QH_LINK_NTDS(8) | QH_LINK_T);

 	le_writeq(whc->pz_list_dma, whc->base + WUSBPERIODICLISTBASE);

 	return 0;
 }

 /**
  * pzl_clean_up - free PZL resources
  * @whc: the WHCI host controller
  *
  * The PZL is stopped and empty.
  */
 void pzl_clean_up(struct whc *whc)
 {
 	if (whc->pz_list)
 		dma_free_coherent(&whc->umc->dev,  sizeof(u64) * 16, whc->pz_list,
 				  whc->pz_list_dma);
 }
	/*
	* Wireless Host Controller (WHC) periodic schedule management.
	*
	* Copyright (C) 2007 Cambridge Silicon Radio Ltd.
	*
	* 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 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/>.
	*/
	#include <linux/kernel.h>
	#include <linux/gfp.h>
	#include <linux/dma-mapping.h>
	#include <linux/uwb/umc.h>
	#include <linux/usb.h>

	#include "../../wusbcore/wusbhc.h"

	#include "whcd.h"

	static void update_pzl_pointers(struct whc *whc, int period, u64 addr)
	{
	switch (period) {
	case 0:
	whc_qset_set_link_ptr(&whc->pz_list[0], addr);
	whc_qset_set_link_ptr(&whc->pz_list[2], addr);
	whc_qset_set_link_ptr(&whc->pz_list[4], addr);
	whc_qset_set_link_ptr(&whc->pz_list[6], addr);
	whc_qset_set_link_ptr(&whc->pz_list[8], addr);
	whc_qset_set_link_ptr(&whc->pz_list[10], addr);
	whc_qset_set_link_ptr(&whc->pz_list[12], addr);
	whc_qset_set_link_ptr(&whc->pz_list[14], addr);
	break;
	case 1:
	whc_qset_set_link_ptr(&whc->pz_list[1], addr);
	whc_qset_set_link_ptr(&whc->pz_list[5], addr);
	whc_qset_set_link_ptr(&whc->pz_list[9], addr);
	whc_qset_set_link_ptr(&whc->pz_list[13], addr);
	break;
	case 2:
	whc_qset_set_link_ptr(&whc->pz_list[3], addr);
	whc_qset_set_link_ptr(&whc->pz_list[11], addr);
	break;
	case 3:
	whc_qset_set_link_ptr(&whc->pz_list[7], addr);
	break;
	case 4:
	whc_qset_set_link_ptr(&whc->pz_list[15], addr);
	break;
	}
	}

	/*
	* Return the 'period' to use for this qset. The minimum interval for
	* the endpoint is used so whatever urbs are submitted the device is
	* polled often enough.
	*/
	static int qset_get_period(struct whc whc, struct whc_qset qset)
	{
	uint8_t bInterval = qset->ep->desc.bInterval;

	if (bInterval < 6)
	bInterval = 6;
	if (bInterval > 10)
	bInterval = 10;
	return bInterval - 6;
	}

	static void qset_insert_in_sw_list(struct whc whc, struct whc_qset qset)
	{
	int period;

	period = qset_get_period(whc, qset);

	qset_clear(whc, qset);
	list_move(&qset->list_node, &whc->periodic_list[period]);
	qset->in_sw_list = true;
	}

	static void pzl_qset_remove(struct whc whc, struct whc_qset qset)
	{
	list_move(&qset->list_node, &whc->periodic_removed_list);
	qset->in_hw_list = false;
	qset->in_sw_list = false;
	}

	/**
	* pzl_process_qset - process any recently inactivated or halted qTDs
	* in a qset.
	*
	* After inactive qTDs are removed, new qTDs can be added if the
	* urb queue still contains URBs.
	*
	* Returns the schedule updates required.
	*/
	static enum whc_update pzl_process_qset(struct whc whc, struct whc_qset qset)
	{
	enum whc_update update = 0;
	uint32_t status = 0;

	while (qset->ntds) {
	struct whc_qtd *td;
	int t;

	t = qset->td_start;
	td = &qset->qtd[qset->td_start];
	status = le32_to_cpu(td->status);

	/*
	* Nothing to do with a still active qTD.
	*/
	if (status & QTD_STS_ACTIVE)
	break;

	if (status & QTD_STS_HALTED) {
	/* Ug, an error. */
	process_halted_qtd(whc, qset, td);
	/* A halted qTD always triggers an update
	because the qset was either removed or
	reactivated. */
	update \|= WHC_UPDATE_UPDATED;
	goto done;
	}

	/* Mmm, a completed qTD. */
	process_inactive_qtd(whc, qset, td);
	}

	if (!qset->remove)
	update \|= qset_add_qtds(whc, qset);

	done:
	/*
	* If there are no qTDs in this qset, remove it from the PZL.
	*/
	if (qset->remove && qset->ntds == 0) {
	pzl_qset_remove(whc, qset);
	update \|= WHC_UPDATE_REMOVED;
	}

	return update;
	}

	/**
	* pzl_start - start the periodic schedule
	* @whc: the WHCI host controller
	*
	* The PZL must be valid (e.g., all entries in the list should have
	* the T bit set).
	*/
	void pzl_start(struct whc *whc)
	{
	le_writeq(whc->pz_list_dma, whc->base + WUSBPERIODICLISTBASE);

	whc_write_wusbcmd(whc, WUSBCMD_PERIODIC_EN, WUSBCMD_PERIODIC_EN);
	whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
	WUSBSTS_PERIODIC_SCHED, WUSBSTS_PERIODIC_SCHED,
	1000, "start PZL");
	}

	/**
	* pzl_stop - stop the periodic schedule
	* @whc: the WHCI host controller
	*/
	void pzl_stop(struct whc *whc)
	{
	whc_write_wusbcmd(whc, WUSBCMD_PERIODIC_EN, 0);
	whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
	WUSBSTS_PERIODIC_SCHED, 0,
	1000, "stop PZL");
	}

	/**
	* pzl_update - request a PZL update and wait for the hardware to be synced
	* @whc: the WHCI HC
	* @wusbcmd: WUSBCMD value to start the update.
	*
	* If the WUSB HC is inactive (i.e., the PZL is stopped) then the
	* update must be skipped as the hardware may not respond to update
	* requests.
	*/
	void pzl_update(struct whc *whc, uint32_t wusbcmd)
	{
	struct wusbhc *wusbhc = &whc->wusbhc;
	long t;

	mutex_lock(&wusbhc->mutex);
	if (wusbhc->active) {
	whc_write_wusbcmd(whc, wusbcmd, wusbcmd);
	t = wait_event_timeout(
	whc->periodic_list_wq,
	(le_readl(whc->base + WUSBCMD) & WUSBCMD_PERIODIC_UPDATED) == 0,
	msecs_to_jiffies(1000));
	if (t == 0)
	whc_hw_error(whc, "PZL update timeout");
	}
	mutex_unlock(&wusbhc->mutex);
	}

	static void update_pzl_hw_view(struct whc *whc)
	{
	struct whc_qset qset, t;
	int period;
	u64 tmp_qh = 0;

	for (period = 0; period < 5; period++) {
	list_for_each_entry_safe(qset, t, &whc->periodic_list[period], list_node) {
	whc_qset_set_link_ptr(&qset->qh.link, tmp_qh);
	tmp_qh = qset->qset_dma;
	qset->in_hw_list = true;
	}
	update_pzl_pointers(whc, period, tmp_qh);
	}
	}

	/**
	* scan_periodic_work - scan the PZL for qsets to process.
	*
	* Process each qset in the PZL in turn and then signal the WHC that
	* the PZL has been updated.
	*
	* Then start, stop or update the periodic schedule as required.
	*/
	void scan_periodic_work(struct work_struct *work)
	{
	struct whc *whc = container_of(work, struct whc, periodic_work);
	struct whc_qset qset, t;
	enum whc_update update = 0;
	int period;

	spin_lock_irq(&whc->lock);

	for (period = 4; period >= 0; period--) {
	list_for_each_entry_safe(qset, t, &whc->periodic_list[period], list_node) {
	if (!qset->in_hw_list)
	update \|= WHC_UPDATE_ADDED;
	update \|= pzl_process_qset(whc, qset);
	}
	}

	if (update & (WHC_UPDATE_ADDED \| WHC_UPDATE_REMOVED))
	update_pzl_hw_view(whc);

	spin_unlock_irq(&whc->lock);

	if (update) {
	uint32_t wusbcmd = WUSBCMD_PERIODIC_UPDATED \| WUSBCMD_PERIODIC_SYNCED_DB;
	if (update & WHC_UPDATE_REMOVED)
	wusbcmd \|= WUSBCMD_PERIODIC_QSET_RM;
	pzl_update(whc, wusbcmd);
	}

	/*
	* Now that the PZL is updated, complete the removal of any
	* removed qsets.
	*
	* If the qset was to be reset, do so and reinsert it into the
	* PZL if it has pending transfers.
	*/
	spin_lock_irq(&whc->lock);

	list_for_each_entry_safe(qset, t, &whc->periodic_removed_list, list_node) {
	qset_remove_complete(whc, qset);
	if (qset->reset) {
	qset_reset(whc, qset);
	if (!list_empty(&qset->stds)) {
	qset_insert_in_sw_list(whc, qset);
	queue_work(whc->workqueue, &whc->periodic_work);
	}
	}
	}

	spin_unlock_irq(&whc->lock);
	}

	/**
	* pzl_urb_enqueue - queue an URB onto the periodic list (PZL)
	* @whc: the WHCI host controller
	* @urb: the URB to enqueue
	* @mem_flags: flags for any memory allocations
	*
	* The qset for the endpoint is obtained and the urb queued on to it.
	*
	* Work is scheduled to update the hardware's view of the PZL.
	*/
	int pzl_urb_enqueue(struct whc whc, struct urb urb, gfp_t mem_flags)
	{
	struct whc_qset *qset;
	int err;
	unsigned long flags;

	spin_lock_irqsave(&whc->lock, flags);

	err = usb_hcd_link_urb_to_ep(&whc->wusbhc.usb_hcd, urb);
	if (err < 0) {
	spin_unlock_irqrestore(&whc->lock, flags);
	return err;
	}

	qset = get_qset(whc, urb, GFP_ATOMIC);
	if (qset == NULL)
	err = -ENOMEM;
	else
	err = qset_add_urb(whc, qset, urb, GFP_ATOMIC);
	if (!err) {
	if (!qset->in_sw_list && !qset->remove)
	qset_insert_in_sw_list(whc, qset);
	} else
	usb_hcd_unlink_urb_from_ep(&whc->wusbhc.usb_hcd, urb);

	spin_unlock_irqrestore(&whc->lock, flags);

	if (!err)
	queue_work(whc->workqueue, &whc->periodic_work);

	return err;
	}

	/**
	* pzl_urb_dequeue - remove an URB (qset) from the periodic list
	* @whc: the WHCI host controller
	* @urb: the URB to dequeue
	* @status: the current status of the URB
	*
	* URBs that do yet have qTDs can simply be removed from the software
	* queue, otherwise the qset must be removed so the qTDs can be safely
	* removed.
	*/
	int pzl_urb_dequeue(struct whc whc, struct urb urb, int status)
	{
	struct whc_urb *wurb = urb->hcpriv;
	struct whc_qset *qset = wurb->qset;
	struct whc_std std, t;
	bool has_qtd = false;
	int ret;
	unsigned long flags;

	spin_lock_irqsave(&whc->lock, flags);

	ret = usb_hcd_check_unlink_urb(&whc->wusbhc.usb_hcd, urb, status);
	if (ret < 0)
	goto out;

	list_for_each_entry_safe(std, t, &qset->stds, list_node) {
	if (std->urb == urb) {
	if (std->qtd)
	has_qtd = true;
	qset_free_std(whc, std);
	} else
	std->qtd = NULL; /* so this std is re-added when the qset is */
	}

	if (has_qtd) {
	pzl_qset_remove(whc, qset);
	update_pzl_hw_view(whc);
	wurb->status = status;
	wurb->is_async = false;
	queue_work(whc->workqueue, &wurb->dequeue_work);
	} else
	qset_remove_urb(whc, qset, urb, status);
	out:
	spin_unlock_irqrestore(&whc->lock, flags);

	return ret;
	}

	/**
	* pzl_qset_delete - delete a qset from the PZL
	*/
	void pzl_qset_delete(struct whc whc, struct whc_qset qset)
	{
	qset->remove = 1;
	queue_work(whc->workqueue, &whc->periodic_work);
	qset_delete(whc, qset);
	}

	/**
	* pzl_init - initialize the periodic zone list
	* @whc: the WHCI host controller
	*/
	int pzl_init(struct whc *whc)
	{
	int i;

	whc->pz_list = dma_alloc_coherent(&whc->umc->dev, sizeof(u64) * 16,
	&whc->pz_list_dma, GFP_KERNEL);
	if (whc->pz_list == NULL)
	return -ENOMEM;

	/* Set T bit on all elements in PZL. */
	for (i = 0; i < 16; i++)
	whc->pz_list[i] = cpu_to_le64(QH_LINK_NTDS(8) \| QH_LINK_T);

	le_writeq(whc->pz_list_dma, whc->base + WUSBPERIODICLISTBASE);

	return 0;
	}

	/**
	* pzl_clean_up - free PZL resources
	* @whc: the WHCI host controller
	*
	* The PZL is stopped and empty.
	*/
	void pzl_clean_up(struct whc *whc)
	{
	if (whc->pz_list)
	dma_free_coherent(&whc->umc->dev, sizeof(u64) * 16, whc->pz_list,
	whc->pz_list_dma);
	}