diff options
Diffstat (limited to 'drivers/uwb/rsv.c')
| -rw-r--r-- | drivers/uwb/rsv.c | 680 |
1 files changed, 680 insertions, 0 deletions
diff --git a/drivers/uwb/rsv.c b/drivers/uwb/rsv.c new file mode 100644 index 0000000..bae16204 --- /dev/null +++ b/drivers/uwb/rsv.c @@ -0,0 +1,680 @@ +/* + * 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); + 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); + set_bit(rsv->stream, rsv->owner->streams); + 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); +} |