/*
 * 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);
}