mmc.c

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/*
 * WUSB Wire Adapter: Control/Data Streaming Interface (WUSB[8])
 * MMC (Microscheduled Management Command) handling
 *
 * Copyright (C) 2005-2006 Intel Corporation
 * Inaky Perez-Gonzalez <[email protected]>
 *
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 *
 * WUIEs and MMC IEs...well, they are almost the same at the end. MMC
 * IEs are Wireless USB IEs that go into the MMC period...[what is
 * that? look in Design-overview.txt].
 *
 *
 * This is a simple subsystem to keep track of which IEs are being
 * sent by the host in the MMC period.
 *
 * For each WUIE we ask to send, we keep it in an array, so we can
 * request its removal later, or replace the content. They are tracked
 * by pointer, so be sure to use the same pointer if you want to
 * remove it or update the contents.
 *
 * FIXME:
 *  - add timers that autoremove intervalled IEs?
 */
#include <linux/usb/wusb.h>
#include <linux/slab.h>
#include <linux/export.h>
#include "wusbhc.h"

/* Initialize the MMCIEs handling mechanism */
int wusbhc_mmcie_create(struct wusbhc *wusbhc)
{
    u8 mmcies = wusbhc->mmcies_max;
    wusbhc->mmcie = kcalloc(mmcies, sizeof(wusbhc->mmcie[0]), GFP_KERNEL);
    if (wusbhc->mmcie == NULL)
        return -ENOMEM;
    mutex_init(&wusbhc->mmcie_mutex);
    return 0;
}

/* Release resources used by the MMCIEs handling mechanism */
void wusbhc_mmcie_destroy(struct wusbhc *wusbhc)
{
    kfree(wusbhc->mmcie);
}

/*
 * Add or replace an MMC Wireless USB IE.
 *
 * @interval:    See WUSB1.0[8.5.3.1]
 * @repeat_cnt:  See WUSB1.0[8.5.3.1]
 * @handle:      See WUSB1.0[8.5.3.1]
 * @wuie:        Pointer to the header of the WUSB IE data to add.
 *               MUST BE allocated in a kmalloc buffer (no stack or
 *               vmalloc).
 *               THE CALLER ALWAYS OWNS THE POINTER (we don't free it
 *               on remove, we just forget about it).
 * @returns:     0 if ok, < 0 errno code on error.
 *
 * Goes over the *whole* @wusbhc->mmcie array looking for (a) the
 * first free spot and (b) if @wuie is already in the array (aka:
 * transmitted in the MMCs) the spot were it is.
 *
 * If present, we "overwrite it" (update).
 *
 *
 * NOTE: Need special ordering rules -- see below WUSB1.0 Table 7-38.
 *       The host uses the handle as the 'sort' index. We
 *       allocate the last one always for the WUIE_ID_HOST_INFO, and
 *       the rest, first come first serve in inverse order.
 *
 *       Host software must make sure that it adds the other IEs in
 *       the right order... the host hardware is responsible for
 *       placing the WCTA IEs in the right place with the other IEs
 *       set by host software.
 *
 * NOTE: we can access wusbhc->wa_descr without locking because it is
 *       read only.
 */
int wusbhc_mmcie_set(struct wusbhc *wusbhc, u8 interval, u8 repeat_cnt,
             struct wuie_hdr *wuie)
{
    int result = -ENOBUFS;
    unsigned handle, itr;

    /* Search a handle, taking into account the ordering */
    mutex_lock(&wusbhc->mmcie_mutex);
    switch (wuie->bIEIdentifier) {
    case WUIE_ID_HOST_INFO:
        /* Always last */
        handle = wusbhc->mmcies_max - 1;
        break;
    case WUIE_ID_ISOCH_DISCARD:
        dev_err(wusbhc->dev, "Special ordering case for WUIE ID 0x%x "
            "unimplemented\n", wuie->bIEIdentifier);
        result = -ENOSYS;
        goto error_unlock;
    default:
        /* search for it or find the last empty slot */
        handle = ~0;
        for (itr = 0; itr < wusbhc->mmcies_max - 1; itr++) {
            if (wusbhc->mmcie[itr] == wuie) {
                handle = itr;
                break;
            }
            if (wusbhc->mmcie[itr] == NULL)
                handle = itr;
        }
        if (handle == ~0)
            goto error_unlock;
    }
    result = (wusbhc->mmcie_add)(wusbhc, interval, repeat_cnt, handle,
                     wuie);
    if (result >= 0)
        wusbhc->mmcie[handle] = wuie;
error_unlock:
    mutex_unlock(&wusbhc->mmcie_mutex);
    return result;
}
EXPORT_SYMBOL_GPL(wusbhc_mmcie_set);

/*
 * Remove an MMC IE previously added with wusbhc_mmcie_set()
 *
 * @wuie    Pointer used to add the WUIE
 */
void wusbhc_mmcie_rm(struct wusbhc *wusbhc, struct wuie_hdr *wuie)
{
    int result;
    unsigned handle, itr;

    mutex_lock(&wusbhc->mmcie_mutex);
    for (itr = 0; itr < wusbhc->mmcies_max; itr++) {
        if (wusbhc->mmcie[itr] == wuie) {
            handle = itr;
            goto found;
        }
    }
    mutex_unlock(&wusbhc->mmcie_mutex);
    return;

found:
    result = (wusbhc->mmcie_rm)(wusbhc, handle);
    if (result == 0)
        wusbhc->mmcie[itr] = NULL;
    mutex_unlock(&wusbhc->mmcie_mutex);
}
EXPORT_SYMBOL_GPL(wusbhc_mmcie_rm);

static int wusbhc_mmc_start(struct wusbhc *wusbhc)
{
    int ret;

    mutex_lock(&wusbhc->mutex);
    ret = wusbhc->start(wusbhc);
    if (ret >= 0)
        wusbhc->active = 1;
    mutex_unlock(&wusbhc->mutex);

    return ret;
}

static void wusbhc_mmc_stop(struct wusbhc *wusbhc)
{
    mutex_lock(&wusbhc->mutex);
    wusbhc->active = 0;
    wusbhc->stop(wusbhc, WUSB_CHANNEL_STOP_DELAY_MS);
    mutex_unlock(&wusbhc->mutex);
}

/*
 * wusbhc_start - start transmitting MMCs and accepting connections
 * @wusbhc: the HC to start
 *
 * Establishes a cluster reservation, enables device connections, and
 * starts MMCs with appropriate DNTS parameters.
 */
int wusbhc_start(struct wusbhc *wusbhc)
{
    int result;
    struct device *dev = wusbhc->dev;

    WARN_ON(wusbhc->wuie_host_info != NULL);

    result = wusbhc_rsv_establish(wusbhc);
    if (result < 0) {
        dev_err(dev, "cannot establish cluster reservation: %d\n",
            result);
        goto error_rsv_establish;
    }

    result = wusbhc_devconnect_start(wusbhc);
    if (result < 0) {
        dev_err(dev, "error enabling device connections: %d\n", result);
        goto error_devconnect_start;
    }

    result = wusbhc_sec_start(wusbhc);
    if (result < 0) {
        dev_err(dev, "error starting security in the HC: %d\n", result);
        goto error_sec_start;
    }
    /* FIXME: the choice of the DNTS parameters is somewhat
     * arbitrary */
    result = wusbhc->set_num_dnts(wusbhc, 0, 15);
    if (result < 0) {
        dev_err(dev, "Cannot set DNTS parameters: %d\n", result);
        goto error_set_num_dnts;
    }
    result = wusbhc_mmc_start(wusbhc);
    if (result < 0) {
        dev_err(dev, "error starting wusbch: %d\n", result);
        goto error_wusbhc_start;
    }

    return 0;

error_wusbhc_start:
    wusbhc_sec_stop(wusbhc);
error_set_num_dnts:
error_sec_start:
    wusbhc_devconnect_stop(wusbhc);
error_devconnect_start:
    wusbhc_rsv_terminate(wusbhc);
error_rsv_establish:
    return result;
}

/*
 * wusbhc_stop - stop transmitting MMCs
 * @wusbhc: the HC to stop
 *
 * Stops the WUSB channel and removes the cluster reservation.
 */
void wusbhc_stop(struct wusbhc *wusbhc)
{
    wusbhc_mmc_stop(wusbhc);
    wusbhc_sec_stop(wusbhc);
    wusbhc_devconnect_stop(wusbhc);
    wusbhc_rsv_terminate(wusbhc);
}

/*
 * Set/reset/update a new CHID
 *
 * Depending on the previous state of the MMCs, start, stop or change
 * the sent MMC. This effectively switches the host controller on and
 * off (radio wise).
 */
int wusbhc_chid_set(struct wusbhc *wusbhc, const struct wusb_ckhdid *chid)
{
    int result = 0;

    if (memcmp(chid, &wusb_ckhdid_zero, sizeof(*chid)) == 0)
        chid = NULL;

    mutex_lock(&wusbhc->mutex);
    if (chid) {
        if (wusbhc->active) {
            mutex_unlock(&wusbhc->mutex);
            return -EBUSY;
        }
        wusbhc->chid = *chid;
    }
    mutex_unlock(&wusbhc->mutex);

    if (chid)
        result = uwb_radio_start(&wusbhc->pal);
    else
        uwb_radio_stop(&wusbhc->pal);
    return result;
}
EXPORT_SYMBOL_GPL(wusbhc_chid_set);