asl.c

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/*
 * Wireless Host Controller (WHC) asynchronous 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 qset_get_next_prev(struct whc *whc, struct whc_qset *qset,
                   struct whc_qset **next, struct whc_qset **prev)
{
    struct list_head *n, *p;

    BUG_ON(list_empty(&whc->async_list));

    n = qset->list_node.next;
    if (n == &whc->async_list)
        n = n->next;
    p = qset->list_node.prev;
    if (p == &whc->async_list)
        p = p->prev;

    *next = container_of(n, struct whc_qset, list_node);
    *prev = container_of(p, struct whc_qset, list_node);

}

static void asl_qset_insert_begin(struct whc *whc, struct whc_qset *qset)
{
    list_move(&qset->list_node, &whc->async_list);
    qset->in_sw_list = true;
}

static void asl_qset_insert(struct whc *whc, struct whc_qset *qset)
{
    struct whc_qset *next, *prev;

    qset_clear(whc, qset);

    /* Link into ASL. */
    qset_get_next_prev(whc, qset, &next, &prev);
    whc_qset_set_link_ptr(&qset->qh.link, next->qset_dma);
    whc_qset_set_link_ptr(&prev->qh.link, qset->qset_dma);
    qset->in_hw_list = true;
}

static void asl_qset_remove(struct whc *whc, struct whc_qset *qset)
{
    struct whc_qset *prev, *next;

    qset_get_next_prev(whc, qset, &next, &prev);

    list_move(&qset->list_node, &whc->async_removed_list);
    qset->in_sw_list = false;

    /*
     * No more qsets in the ASL?  The caller must stop the ASL as
     * it's no longer valid.
     */
    if (list_empty(&whc->async_list))
        return;

    /* Remove from ASL. */
    whc_qset_set_link_ptr(&prev->qh.link, next->qset_dma);
    qset->in_hw_list = false;
}

static uint32_t 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:
    /*
     * Remove this qset from the ASL if requested, but only if has
     * no qTDs.
     */
    if (qset->remove && qset->ntds == 0) {
        asl_qset_remove(whc, qset);
        update |= WHC_UPDATE_REMOVED;
    }
    return update;
}

void asl_start(struct whc *whc)
{
    struct whc_qset *qset;

    qset = list_first_entry(&whc->async_list, struct whc_qset, list_node);

    le_writeq(qset->qset_dma | QH_LINK_NTDS(8), whc->base + WUSBASYNCLISTADDR);

    whc_write_wusbcmd(whc, WUSBCMD_ASYNC_EN, WUSBCMD_ASYNC_EN);
    whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
              WUSBSTS_ASYNC_SCHED, WUSBSTS_ASYNC_SCHED,
              1000, "start ASL");
}

void asl_stop(struct whc *whc)
{
    whc_write_wusbcmd(whc, WUSBCMD_ASYNC_EN, 0);
    whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
              WUSBSTS_ASYNC_SCHED, 0,
              1000, "stop ASL");
}

void asl_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->async_list_wq,
            (le_readl(whc->base + WUSBCMD) & WUSBCMD_ASYNC_UPDATED) == 0,
            msecs_to_jiffies(1000));
        if (t == 0)
            whc_hw_error(whc, "ASL update timeout");
    }
    mutex_unlock(&wusbhc->mutex);
}

void scan_async_work(struct work_struct *work)
{
    struct whc *whc = container_of(work, struct whc, async_work);
    struct whc_qset *qset, *t;
    enum whc_update update = 0;

    spin_lock_irq(&whc->lock);

    /*
     * Transerve the software list backwards so new qsets can be
     * safely inserted into the ASL without making it non-circular.
     */
    list_for_each_entry_safe_reverse(qset, t, &whc->async_list, list_node) {
        if (!qset->in_hw_list) {
            asl_qset_insert(whc, qset);
            update |= WHC_UPDATE_ADDED;
        }

        update |= process_qset(whc, qset);
    }

    spin_unlock_irq(&whc->lock);

    if (update) {
        uint32_t wusbcmd = WUSBCMD_ASYNC_UPDATED | WUSBCMD_ASYNC_SYNCED_DB;
        if (update & WHC_UPDATE_REMOVED)
            wusbcmd |= WUSBCMD_ASYNC_QSET_RM;
        asl_update(whc, wusbcmd);
    }

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

    list_for_each_entry_safe(qset, t, &whc->async_removed_list, list_node) {
        qset_remove_complete(whc, qset);
        if (qset->reset) {
            qset_reset(whc, qset);
            if (!list_empty(&qset->stds)) {
                asl_qset_insert_begin(whc, qset);
                queue_work(whc->workqueue, &whc->async_work);
            }
        }
    }

    spin_unlock_irq(&whc->lock);
}

int asl_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)
            asl_qset_insert_begin(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->async_work);

    return err;
}

int asl_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) {
        asl_qset_remove(whc, qset);
        wurb->status = status;
        wurb->is_async = true;
        queue_work(whc->workqueue, &wurb->dequeue_work);
    } else
        qset_remove_urb(whc, qset, urb, status);
out:
    spin_unlock_irqrestore(&whc->lock, flags);

    return ret;
}

void asl_qset_delete(struct whc *whc, struct whc_qset *qset)
{
    qset->remove = 1;
    queue_work(whc->workqueue, &whc->async_work);
    qset_delete(whc, qset);
}

int asl_init(struct whc *whc)
{
    struct whc_qset *qset;

    qset = qset_alloc(whc, GFP_KERNEL);
    if (qset == NULL)
        return -ENOMEM;

    asl_qset_insert_begin(whc, qset);
    asl_qset_insert(whc, qset);

    return 0;
}

void asl_clean_up(struct whc *whc)
{
    struct whc_qset *qset;

    if (!list_empty(&whc->async_list)) {
        qset = list_first_entry(&whc->async_list, struct whc_qset, list_node);
        list_del(&qset->list_node);
        qset_free(whc, qset);
    }
}