[deliverable/linux.git] / drivers / uwb / rsv.c

/*
 * UWB reservation management.
 *
 * Copyright (C) 2008 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/version.h>
#include <linux/kernel.h>
#include <linux/uwb.h>

#include "uwb-internal.h"

static void uwb_rsv_timer(unsigned long arg);

static const char *rsv_states[] = {
        [UWB_RSV_STATE_NONE]          = "none",
        [UWB_RSV_STATE_O_INITIATED]   = "initiated",
        [UWB_RSV_STATE_O_PENDING]     = "pending",
        [UWB_RSV_STATE_O_MODIFIED]    = "modified",
        [UWB_RSV_STATE_O_ESTABLISHED] = "established",
        [UWB_RSV_STATE_T_ACCEPTED]    = "accepted",
        [UWB_RSV_STATE_T_DENIED]      = "denied",
        [UWB_RSV_STATE_T_PENDING]     = "pending",
};

static const char *rsv_types[] = {
        [UWB_DRP_TYPE_ALIEN_BP] = "alien-bp",
        [UWB_DRP_TYPE_HARD]     = "hard",
        [UWB_DRP_TYPE_SOFT]     = "soft",
        [UWB_DRP_TYPE_PRIVATE]  = "private",
        [UWB_DRP_TYPE_PCA]      = "pca",
};

/**
 * uwb_rsv_state_str - return a string for a reservation state
 * @state: the reservation state.
 */
const char *uwb_rsv_state_str(enum uwb_rsv_state state)
{
        if (state < UWB_RSV_STATE_NONE || state >= UWB_RSV_STATE_LAST)
                return "unknown";
        return rsv_states[state];
}
EXPORT_SYMBOL_GPL(uwb_rsv_state_str);

/**
 * uwb_rsv_type_str - return a string for a reservation type
 * @type: the reservation type
 */
const char *uwb_rsv_type_str(enum uwb_drp_type type)
{
        if (type < UWB_DRP_TYPE_ALIEN_BP || type > UWB_DRP_TYPE_PCA)
                return "invalid";
        return rsv_types[type];
}
EXPORT_SYMBOL_GPL(uwb_rsv_type_str);

static void uwb_rsv_dump(struct uwb_rsv *rsv)
{
        struct device *dev = &rsv->rc->uwb_dev.dev;
        struct uwb_dev_addr devaddr;
        char owner[UWB_ADDR_STRSIZE], target[UWB_ADDR_STRSIZE];

        uwb_dev_addr_print(owner, sizeof(owner), &rsv->owner->dev_addr);
        if (rsv->target.type == UWB_RSV_TARGET_DEV)
                devaddr = rsv->target.dev->dev_addr;
        else
                devaddr = rsv->target.devaddr;
        uwb_dev_addr_print(target, sizeof(target), &devaddr);

        dev_dbg(dev, "rsv %s -> %s: %s\n", owner, target, uwb_rsv_state_str(rsv->state));
}

/*
 * Get a free stream index for a reservation.
 *
 * If the target is a DevAddr (e.g., a WUSB cluster reservation) then
 * the stream is allocated from a pool of per-RC stream indexes,
 * otherwise a unique stream index for the target is selected.
 */
static int uwb_rsv_get_stream(struct uwb_rsv *rsv)
{
        struct uwb_rc *rc = rsv->rc;
        unsigned long *streams_bm;
        int stream;

        switch (rsv->target.type) {
        case UWB_RSV_TARGET_DEV:
                streams_bm = rsv->target.dev->streams;
                break;
        case UWB_RSV_TARGET_DEVADDR:
                streams_bm = rc->uwb_dev.streams;
                break;
        default:
                return -EINVAL;
        }

        stream = find_first_zero_bit(streams_bm, UWB_NUM_STREAMS);
        if (stream >= UWB_NUM_STREAMS)
                return -EBUSY;

        rsv->stream = stream;
        set_bit(stream, streams_bm);

        return 0;
}

static void uwb_rsv_put_stream(struct uwb_rsv *rsv)
{
        struct uwb_rc *rc = rsv->rc;
        unsigned long *streams_bm;

        switch (rsv->target.type) {
        case UWB_RSV_TARGET_DEV:
                streams_bm = rsv->target.dev->streams;
                break;
        case UWB_RSV_TARGET_DEVADDR:
                streams_bm = rc->uwb_dev.streams;
                break;
        default:
                return;
        }

        clear_bit(rsv->stream, streams_bm);
}

/*
 * Generate a MAS allocation with a single row component.
 */
static void uwb_rsv_gen_alloc_row(struct uwb_mas_bm *mas,
                                  int first_mas, int mas_per_zone,
                                  int zs, int ze)
{
        struct uwb_mas_bm col;
        int z;

        bitmap_zero(mas->bm, UWB_NUM_MAS);
        bitmap_zero(col.bm, UWB_NUM_MAS);
        bitmap_fill(col.bm, mas_per_zone);
        bitmap_shift_left(col.bm, col.bm, first_mas + zs * UWB_MAS_PER_ZONE, UWB_NUM_MAS);

        for (z = zs; z <= ze; z++) {
                bitmap_or(mas->bm, mas->bm, col.bm, UWB_NUM_MAS);
                bitmap_shift_left(col.bm, col.bm, UWB_MAS_PER_ZONE, UWB_NUM_MAS);
        }
}

/*
 * Allocate some MAS for this reservation based on current local
 * availability, the reservation parameters (max_mas, min_mas,
 * sparsity), and the WiMedia rules for MAS allocations.
 *
 * Returns -EBUSY is insufficient free MAS are available.
 *
 * FIXME: to simplify this, only safe reservations with a single row
 * component in zones 1 to 15 are tried (zone 0 is skipped to avoid
 * problems with the MAS reserved for the BP).
 *
 * [ECMA-368] section B.2.
 */
static int uwb_rsv_alloc_mas(struct uwb_rsv *rsv)
{
        static const int safe_mas_in_row[UWB_NUM_ZONES] = {
                8, 7, 6, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 2, 1,
        };
        int n, r;
        struct uwb_mas_bm mas;
        bool found = false;

        /*
         * Search all valid safe allocations until either: too few MAS
         * are available; or the smallest allocation with sufficient
         * MAS is found.
         *
         * The top of the zones are preferred, so space for larger
         * allocations is available in the bottom of the zone (e.g., a
         * 15 MAS allocation should start in row 14 leaving space for
         * a 120 MAS allocation at row 0).
         */
        for (n = safe_mas_in_row[0]; n >= 1; n--) {
                int num_mas;

                num_mas = n * (UWB_NUM_ZONES - 1);
                if (num_mas < rsv->min_mas)
                        break;
                if (found && num_mas < rsv->max_mas)
                        break;

                for (r = UWB_MAS_PER_ZONE-1;  r >= 0; r--) {
                        if (safe_mas_in_row[r] < n)
                                continue;
                        uwb_rsv_gen_alloc_row(&mas, r, n, 1, UWB_NUM_ZONES);
                        if (uwb_drp_avail_reserve_pending(rsv->rc, &mas) == 0) {
                                found = true;
                                break;
                        }
                }
        }

        if (!found)
                return -EBUSY;

        bitmap_copy(rsv->mas.bm, mas.bm, UWB_NUM_MAS);
        return 0;
}

static void uwb_rsv_stroke_timer(struct uwb_rsv *rsv)
{
        int sframes = UWB_MAX_LOST_BEACONS;

        /*
         * Multicast reservations can become established within 1
         * super frame and should not be terminated if no response is
         * received.
         */
        if (rsv->is_multicast) {
                if (rsv->state == UWB_RSV_STATE_O_INITIATED)
                        sframes = 1;
                if (rsv->state == UWB_RSV_STATE_O_ESTABLISHED)
                        sframes = 0;
        }

        rsv->expired = false;
        if (sframes > 0) {
                /*
                 * Add an additional 2 superframes to account for the
                 * time to send the SET DRP IE command.
                 */
                unsigned timeout_us = (sframes + 2) * UWB_SUPERFRAME_LENGTH_US;
                mod_timer(&rsv->timer, jiffies + usecs_to_jiffies(timeout_us));
        } else
                del_timer(&rsv->timer);
}

/*
 * Update a reservations state, and schedule an update of the
 * transmitted DRP IEs.
 */
static void uwb_rsv_state_update(struct uwb_rsv *rsv,
                                 enum uwb_rsv_state new_state)
{
        rsv->state = new_state;
        rsv->ie_valid = false;

        uwb_rsv_dump(rsv);

        uwb_rsv_stroke_timer(rsv);
        uwb_rsv_sched_update(rsv->rc);
}

static void uwb_rsv_callback(struct uwb_rsv *rsv)
{
        if (rsv->callback)
                rsv->callback(rsv);
}

void uwb_rsv_set_state(struct uwb_rsv *rsv, enum uwb_rsv_state new_state)
{
        if (rsv->state == new_state) {
                switch (rsv->state) {
                case UWB_RSV_STATE_O_ESTABLISHED:
                case UWB_RSV_STATE_T_ACCEPTED:
                case UWB_RSV_STATE_NONE:
                        uwb_rsv_stroke_timer(rsv);
                        break;
                default:
                        /* Expecting a state transition so leave timer
                           as-is. */
                        break;
                }
                return;
        }

        switch (new_state) {
        case UWB_RSV_STATE_NONE:
                uwb_drp_avail_release(rsv->rc, &rsv->mas);
                if (uwb_rsv_is_owner(rsv))
                        uwb_rsv_put_stream(rsv);
                uwb_rsv_state_update(rsv, UWB_RSV_STATE_NONE);
                uwb_rsv_callback(rsv);
                break;
        case UWB_RSV_STATE_O_INITIATED:
                uwb_rsv_state_update(rsv, UWB_RSV_STATE_O_INITIATED);
                break;
        case UWB_RSV_STATE_O_PENDING:
                uwb_rsv_state_update(rsv, UWB_RSV_STATE_O_PENDING);
                break;
        case UWB_RSV_STATE_O_ESTABLISHED:
                uwb_drp_avail_reserve(rsv->rc, &rsv->mas);
                uwb_rsv_state_update(rsv, UWB_RSV_STATE_O_ESTABLISHED);
                uwb_rsv_callback(rsv);
                break;
        case UWB_RSV_STATE_T_ACCEPTED:
                uwb_drp_avail_reserve(rsv->rc, &rsv->mas);
                uwb_rsv_state_update(rsv, UWB_RSV_STATE_T_ACCEPTED);
                uwb_rsv_callback(rsv);
                break;
        case UWB_RSV_STATE_T_DENIED:
                uwb_rsv_state_update(rsv, UWB_RSV_STATE_T_DENIED);
                break;
        default:
                dev_err(&rsv->rc->uwb_dev.dev, "unhandled state: %s (%d)\n",
                        uwb_rsv_state_str(new_state), new_state);
        }
}

static struct uwb_rsv *uwb_rsv_alloc(struct uwb_rc *rc)
{
        struct uwb_rsv *rsv;

        rsv = kzalloc(sizeof(struct uwb_rsv), GFP_KERNEL);
        if (!rsv)
                return NULL;

        INIT_LIST_HEAD(&rsv->rc_node);
        INIT_LIST_HEAD(&rsv->pal_node);
        init_timer(&rsv->timer);
        rsv->timer.function = uwb_rsv_timer;
        rsv->timer.data     = (unsigned long)rsv;

        rsv->rc = rc;

        return rsv;
}

static void uwb_rsv_free(struct uwb_rsv *rsv)
{
        uwb_dev_put(rsv->owner);
        if (rsv->target.type == UWB_RSV_TARGET_DEV)
                uwb_dev_put(rsv->target.dev);
        kfree(rsv);
}

/**
 * uwb_rsv_create - allocate and initialize a UWB reservation structure
 * @rc: the radio controller
 * @cb: callback to use when the reservation completes or terminates
 * @pal_priv: data private to the PAL to be passed in the callback
 *
 * The callback is called when the state of the reservation changes from:
 *
 *   - pending to accepted
 *   - pending to denined
 *   - accepted to terminated
 *   - pending to terminated
 */
struct uwb_rsv *uwb_rsv_create(struct uwb_rc *rc, uwb_rsv_cb_f cb, void *pal_priv)
{
        struct uwb_rsv *rsv;

        rsv = uwb_rsv_alloc(rc);
        if (!rsv)
                return NULL;

        rsv->callback = cb;
        rsv->pal_priv = pal_priv;

        return rsv;
}
EXPORT_SYMBOL_GPL(uwb_rsv_create);

void uwb_rsv_remove(struct uwb_rsv *rsv)
{
        if (rsv->state != UWB_RSV_STATE_NONE)
                uwb_rsv_set_state(rsv, UWB_RSV_STATE_NONE);
        del_timer_sync(&rsv->timer);
        list_del(&rsv->rc_node);
        uwb_rsv_free(rsv);
}

/**
 * uwb_rsv_destroy - free a UWB reservation structure
 * @rsv: the reservation to free
 *
 * The reservation will be terminated if it is pending or established.
 */
void uwb_rsv_destroy(struct uwb_rsv *rsv)
{
        struct uwb_rc *rc = rsv->rc;

        mutex_lock(&rc->rsvs_mutex);
        uwb_rsv_remove(rsv);
        mutex_unlock(&rc->rsvs_mutex);
}
EXPORT_SYMBOL_GPL(uwb_rsv_destroy);

/**
 * usb_rsv_establish - start a reservation establishment
 * @rsv: the reservation
 *
 * The PAL should fill in @rsv's owner, target, type, max_mas,
 * min_mas, sparsity and is_multicast fields.  If the target is a
 * uwb_dev it must be referenced.
 *
 * The reservation's callback will be called when the reservation is
 * accepted, denied or times out.
 */
int uwb_rsv_establish(struct uwb_rsv *rsv)
{
        struct uwb_rc *rc = rsv->rc;
        int ret;

        mutex_lock(&rc->rsvs_mutex);

        ret = uwb_rsv_get_stream(rsv);
        if (ret)
                goto out;

        ret = uwb_rsv_alloc_mas(rsv);
        if (ret) {
                uwb_rsv_put_stream(rsv);
                goto out;
        }

        list_add_tail(&rsv->rc_node, &rc->reservations);
        rsv->owner = &rc->uwb_dev;
        uwb_dev_get(rsv->owner);
        uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_INITIATED);
out:
        mutex_unlock(&rc->rsvs_mutex);
        return ret;
}
EXPORT_SYMBOL_GPL(uwb_rsv_establish);

/**
 * uwb_rsv_modify - modify an already established reservation
 * @rsv: the reservation to modify
 * @max_mas: new maximum MAS to reserve
 * @min_mas: new minimum MAS to reserve
 * @sparsity: new sparsity to use
 *
 * FIXME: implement this once there are PALs that use it.
 */
int uwb_rsv_modify(struct uwb_rsv *rsv, int max_mas, int min_mas, int sparsity)
{
        return -ENOSYS;
}
EXPORT_SYMBOL_GPL(uwb_rsv_modify);

/**
 * uwb_rsv_terminate - terminate an established reservation
 * @rsv: the reservation to terminate
 *
 * A reservation is terminated by removing the DRP IE from the beacon,
 * the other end will consider the reservation to be terminated when
 * it does not see the DRP IE for at least mMaxLostBeacons.
 *
 * If applicable, the reference to the target uwb_dev will be released.
 */
void uwb_rsv_terminate(struct uwb_rsv *rsv)
{
        struct uwb_rc *rc = rsv->rc;

        mutex_lock(&rc->rsvs_mutex);

        uwb_rsv_set_state(rsv, UWB_RSV_STATE_NONE);

        mutex_unlock(&rc->rsvs_mutex);
}
EXPORT_SYMBOL_GPL(uwb_rsv_terminate);

/**
 * uwb_rsv_accept - accept a new reservation from a peer
 * @rsv:      the reservation
 * @cb:       call back for reservation changes
 * @pal_priv: data to be passed in the above call back
 *
 * Reservation requests from peers are denied unless a PAL accepts it
 * by calling this function.
 */
void uwb_rsv_accept(struct uwb_rsv *rsv, uwb_rsv_cb_f cb, void *pal_priv)
{
        rsv->callback = cb;
        rsv->pal_priv = pal_priv;
        rsv->state    = UWB_RSV_STATE_T_ACCEPTED;
}
EXPORT_SYMBOL_GPL(uwb_rsv_accept);

/*
 * Is a received DRP IE for this reservation?
 */
static bool uwb_rsv_match(struct uwb_rsv *rsv, struct uwb_dev *src,
                          struct uwb_ie_drp *drp_ie)
{
        struct uwb_dev_addr *rsv_src;
        int stream;

        stream = uwb_ie_drp_stream_index(drp_ie);

        if (rsv->stream != stream)
                return false;

        switch (rsv->target.type) {
        case UWB_RSV_TARGET_DEVADDR:
                return rsv->stream == stream;
        case UWB_RSV_TARGET_DEV:
                if (uwb_ie_drp_owner(drp_ie))
                        rsv_src = &rsv->owner->dev_addr;
                else
                        rsv_src = &rsv->target.dev->dev_addr;
                return uwb_dev_addr_cmp(&src->dev_addr, rsv_src) == 0;
        }
        return false;
}

static struct uwb_rsv *uwb_rsv_new_target(struct uwb_rc *rc,
                                          struct uwb_dev *src,
                                          struct uwb_ie_drp *drp_ie)
{
        struct uwb_rsv *rsv;
        struct uwb_pal *pal;
        enum uwb_rsv_state state;

        rsv = uwb_rsv_alloc(rc);
        if (!rsv)
                return NULL;

        rsv->rc          = rc;
        rsv->owner       = src;
        uwb_dev_get(rsv->owner);
        rsv->target.type = UWB_RSV_TARGET_DEV;
        rsv->target.dev  = &rc->uwb_dev;
        rsv->type        = uwb_ie_drp_type(drp_ie);
        rsv->stream      = uwb_ie_drp_stream_index(drp_ie);
        uwb_drp_ie_to_bm(&rsv->mas, drp_ie);

        /*
         * See if any PALs are interested in this reservation. If not,
         * deny the request.
         */
        rsv->state = UWB_RSV_STATE_T_DENIED;
        spin_lock(&rc->pal_lock);
        list_for_each_entry(pal, &rc->pals, node) {
                if (pal->new_rsv)
                        pal->new_rsv(rsv);
                if (rsv->state == UWB_RSV_STATE_T_ACCEPTED)
                        break;
        }
        spin_unlock(&rc->pal_lock);

        list_add_tail(&rsv->rc_node, &rc->reservations);
        state = rsv->state;
        rsv->state = UWB_RSV_STATE_NONE;
        uwb_rsv_set_state(rsv, state);

        return rsv;
}

/**
 * uwb_rsv_find - find a reservation for a received DRP IE.
 * @rc: the radio controller
 * @src: source of the DRP IE
 * @drp_ie: the DRP IE
 *
 * If the reservation cannot be found and the DRP IE is from a peer
 * attempting to establish a new reservation, create a new reservation
 * and add it to the list.
 */
struct uwb_rsv *uwb_rsv_find(struct uwb_rc *rc, struct uwb_dev *src,
                             struct uwb_ie_drp *drp_ie)
{
        struct uwb_rsv *rsv;

        list_for_each_entry(rsv, &rc->reservations, rc_node) {
                if (uwb_rsv_match(rsv, src, drp_ie))
                        return rsv;
        }

        if (uwb_ie_drp_owner(drp_ie))
                return uwb_rsv_new_target(rc, src, drp_ie);

        return NULL;
}

/*
 * Go through all the reservations and check for timeouts and (if
 * necessary) update their DRP IEs.
 *
 * FIXME: look at building the SET_DRP_IE command here rather than
 * having to rescan the list in uwb_rc_send_all_drp_ie().
 */
static bool uwb_rsv_update_all(struct uwb_rc *rc)
{
        struct uwb_rsv *rsv, *t;
        bool ie_updated = false;

        list_for_each_entry_safe(rsv, t, &rc->reservations, rc_node) {
                if (rsv->expired)
                        uwb_drp_handle_timeout(rsv);
                if (!rsv->ie_valid) {
                        uwb_drp_ie_update(rsv);
                        ie_updated = true;
                }
        }

        return ie_updated;
}

void uwb_rsv_sched_update(struct uwb_rc *rc)
{
        queue_work(rc->rsv_workq, &rc->rsv_update_work);
}

/*
 * Update DRP IEs and, if necessary, the DRP Availability IE and send
 * the updated IEs to the radio controller.
 */
static void uwb_rsv_update_work(struct work_struct *work)
{
        struct uwb_rc *rc = container_of(work, struct uwb_rc, rsv_update_work);
        bool ie_updated;

        mutex_lock(&rc->rsvs_mutex);

        ie_updated = uwb_rsv_update_all(rc);

        if (!rc->drp_avail.ie_valid) {
                uwb_drp_avail_ie_update(rc);
                ie_updated = true;
        }

        if (ie_updated)
                uwb_rc_send_all_drp_ie(rc);

        mutex_unlock(&rc->rsvs_mutex);
}

static void uwb_rsv_timer(unsigned long arg)
{
        struct uwb_rsv *rsv = (struct uwb_rsv *)arg;

        rsv->expired = true;
        uwb_rsv_sched_update(rsv->rc);
}

void uwb_rsv_init(struct uwb_rc *rc)
{
        INIT_LIST_HEAD(&rc->reservations);
        mutex_init(&rc->rsvs_mutex);
        INIT_WORK(&rc->rsv_update_work, uwb_rsv_update_work);

        bitmap_complement(rc->uwb_dev.streams, rc->uwb_dev.streams, UWB_NUM_STREAMS);
}

int uwb_rsv_setup(struct uwb_rc *rc)
{
        char name[16];

        snprintf(name, sizeof(name), "%s_rsvd", dev_name(&rc->uwb_dev.dev));
        rc->rsv_workq = create_singlethread_workqueue(name);
        if (rc->rsv_workq == NULL)
                return -ENOMEM;

        return 0;
}

void uwb_rsv_cleanup(struct uwb_rc *rc)
{
        struct uwb_rsv *rsv, *t;

        mutex_lock(&rc->rsvs_mutex);
        list_for_each_entry_safe(rsv, t, &rc->reservations, rc_node) {
                uwb_rsv_remove(rsv);
        }
        mutex_unlock(&rc->rsvs_mutex);

        cancel_work_sync(&rc->rsv_update_work);
        destroy_workqueue(rc->rsv_workq);
}