diff options
Diffstat (limited to 'drivers/uwb/uwbd.c')
| -rw-r--r-- | drivers/uwb/uwbd.c | 410 |
1 files changed, 410 insertions, 0 deletions
diff --git a/drivers/uwb/uwbd.c b/drivers/uwb/uwbd.c new file mode 100644 index 00000000000..78908416e42 --- /dev/null +++ b/drivers/uwb/uwbd.c @@ -0,0 +1,410 @@ +/* + * Ultra Wide Band + * Neighborhood Management Daemon + * + * Copyright (C) 2005-2006 Intel Corporation + * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com> + * + * 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. + * + * + * This daemon takes care of maintaing information that describes the + * UWB neighborhood that the radios in this machine can see. It also + * keeps a tab of which devices are visible, makes sure each HC sits + * on a different channel to avoid interfering, etc. + * + * Different drivers (radio controller, device, any API in general) + * communicate with this daemon through an event queue. Daemon wakes + * up, takes a list of events and handles them one by one; handling + * function is extracted from a table based on the event's type and + * subtype. Events are freed only if the handling function says so. + * + * . Lock protecting the event list has to be an spinlock and locked + * with IRQSAVE because it might be called from an interrupt + * context (ie: when events arrive and the notification drops + * down from the ISR). + * + * . UWB radio controller drivers queue events to the daemon using + * uwbd_event_queue(). They just get the event, chew it to make it + * look like UWBD likes it and pass it in a buffer allocated with + * uwb_event_alloc(). + * + * EVENTS + * + * Events have a type, a subtype, a lenght, some other stuff and the + * data blob, which depends on the event. The header is 'struct + * uwb_event'; for payloads, see 'struct uwbd_evt_*'. + * + * EVENT HANDLER TABLES + * + * To find a handling function for an event, the type is used to index + * a subtype-table in the type-table. The subtype-table is indexed + * with the subtype to get the function that handles the event. Start + * with the main type-table 'uwbd_evt_type_handler'. + * + * DEVICES + * + * Devices are created when a bunch of beacons have been received and + * it is stablished that the device has stable radio presence. CREATED + * only, not configured. Devices are ONLY configured when an + * Application-Specific IE Probe is receieved, in which the device + * declares which Protocol ID it groks. Then the device is CONFIGURED + * (and the driver->probe() stuff of the device model is invoked). + * + * Devices are considered disconnected when a certain number of + * beacons are not received in an amount of time. + * + * Handler functions are called normally uwbd_evt_handle_*(). + */ + +#include <linux/kthread.h> +#include <linux/module.h> +#include <linux/freezer.h> +#include "uwb-internal.h" + +#define D_LOCAL 1 +#include <linux/uwb/debug.h> + + +/** + * UWBD Event handler function signature + * + * Return !0 if the event needs not to be freed (ie the handler + * takes/took care of it). 0 means the daemon code will free the + * event. + * + * @evt->rc is already referenced and guaranteed to exist. See + * uwb_evt_handle(). + */ +typedef int (*uwbd_evt_handler_f)(struct uwb_event *); + +/** + * Properties of a UWBD event + * + * @handler: the function that will handle this event + * @name: text name of event + */ +struct uwbd_event { + uwbd_evt_handler_f handler; + const char *name; +}; + +/** Table of handlers for and properties of the UWBD Radio Control Events */ +static +struct uwbd_event uwbd_events[] = { + [UWB_RC_EVT_BEACON] = { + .handler = uwbd_evt_handle_rc_beacon, + .name = "BEACON_RECEIVED" + }, + [UWB_RC_EVT_BEACON_SIZE] = { + .handler = uwbd_evt_handle_rc_beacon_size, + .name = "BEACON_SIZE_CHANGE" + }, + [UWB_RC_EVT_BPOIE_CHANGE] = { + .handler = uwbd_evt_handle_rc_bpoie_change, + .name = "BPOIE_CHANGE" + }, + [UWB_RC_EVT_BP_SLOT_CHANGE] = { + .handler = uwbd_evt_handle_rc_bp_slot_change, + .name = "BP_SLOT_CHANGE" + }, + [UWB_RC_EVT_DRP_AVAIL] = { + .handler = uwbd_evt_handle_rc_drp_avail, + .name = "DRP_AVAILABILITY_CHANGE" + }, + [UWB_RC_EVT_DRP] = { + .handler = uwbd_evt_handle_rc_drp, + .name = "DRP" + }, + [UWB_RC_EVT_DEV_ADDR_CONFLICT] = { + .handler = uwbd_evt_handle_rc_dev_addr_conflict, + .name = "DEV_ADDR_CONFLICT", + }, +}; + + + +struct uwbd_evt_type_handler { + const char *name; + struct uwbd_event *uwbd_events; + size_t size; +}; + +#define UWBD_EVT_TYPE_HANDLER(n,a) { \ + .name = (n), \ + .uwbd_events = (a), \ + .size = sizeof(a)/sizeof((a)[0]) \ +} + + +/** Table of handlers for each UWBD Event type. */ +static +struct uwbd_evt_type_handler uwbd_evt_type_handlers[] = { + [UWB_RC_CET_GENERAL] = UWBD_EVT_TYPE_HANDLER("RC", uwbd_events) +}; + +static const +size_t uwbd_evt_type_handlers_len = + sizeof(uwbd_evt_type_handlers) / sizeof(uwbd_evt_type_handlers[0]); + +static const struct uwbd_event uwbd_message_handlers[] = { + [UWB_EVT_MSG_RESET] = { + .handler = uwbd_msg_handle_reset, + .name = "reset", + }, +}; + +static DEFINE_MUTEX(uwbd_event_mutex); + +/** + * Handle an URC event passed to the UWB Daemon + * + * @evt: the event to handle + * @returns: 0 if the event can be kfreed, !0 on the contrary + * (somebody else took ownership) [coincidentally, returning + * a <0 errno code will free it :)]. + * + * Looks up the two indirection tables (one for the type, one for the + * subtype) to decide which function handles it and then calls the + * handler. + * + * The event structure passed to the event handler has the radio + * controller in @evt->rc referenced. The reference will be dropped + * once the handler returns, so if it needs it for longer (async), + * it'll need to take another one. + */ +static +int uwbd_event_handle_urc(struct uwb_event *evt) +{ + struct uwbd_evt_type_handler *type_table; + uwbd_evt_handler_f handler; + u8 type, context; + u16 event; + + type = evt->notif.rceb->bEventType; + event = le16_to_cpu(evt->notif.rceb->wEvent); + context = evt->notif.rceb->bEventContext; + + if (type > uwbd_evt_type_handlers_len) { + printk(KERN_ERR "UWBD: event type %u: unknown (too high)\n", type); + return -EINVAL; + } + type_table = &uwbd_evt_type_handlers[type]; + if (type_table->uwbd_events == NULL) { + printk(KERN_ERR "UWBD: event type %u: unknown\n", type); + return -EINVAL; + } + if (event > type_table->size) { + printk(KERN_ERR "UWBD: event %s[%u]: unknown (too high)\n", + type_table->name, event); + return -EINVAL; + } + handler = type_table->uwbd_events[event].handler; + if (handler == NULL) { + printk(KERN_ERR "UWBD: event %s[%u]: unknown\n", type_table->name, event); + return -EINVAL; + } + return (*handler)(evt); +} + +static void uwbd_event_handle_message(struct uwb_event *evt) +{ + struct uwb_rc *rc; + int result; + + rc = evt->rc; + + if (evt->message < 0 || evt->message >= ARRAY_SIZE(uwbd_message_handlers)) { + dev_err(&rc->uwb_dev.dev, "UWBD: invalid message type %d\n", evt->message); + return; + } + + /* If this is a reset event we need to drop the + * uwbd_event_mutex or it deadlocks when the reset handler + * attempts to flush the uwbd events. */ + if (evt->message == UWB_EVT_MSG_RESET) + mutex_unlock(&uwbd_event_mutex); + + result = uwbd_message_handlers[evt->message].handler(evt); + if (result < 0) + dev_err(&rc->uwb_dev.dev, "UWBD: '%s' message failed: %d\n", + uwbd_message_handlers[evt->message].name, result); + + if (evt->message == UWB_EVT_MSG_RESET) + mutex_lock(&uwbd_event_mutex); +} + +static void uwbd_event_handle(struct uwb_event *evt) +{ + struct uwb_rc *rc; + int should_keep; + + rc = evt->rc; + + if (rc->ready) { + switch (evt->type) { + case UWB_EVT_TYPE_NOTIF: + should_keep = uwbd_event_handle_urc(evt); + if (should_keep <= 0) + kfree(evt->notif.rceb); + break; + case UWB_EVT_TYPE_MSG: + uwbd_event_handle_message(evt); + break; + default: + dev_err(&rc->uwb_dev.dev, "UWBD: invalid event type %d\n", evt->type); + break; + } + } + + __uwb_rc_put(rc); /* for the __uwb_rc_get() in uwb_rc_notif_cb() */ +} +/* The UWB Daemon */ + + +/** Daemon's PID: used to decide if we can queue or not */ +static int uwbd_pid; +/** Daemon's task struct for managing the kthread */ +static struct task_struct *uwbd_task; +/** Daemon's waitqueue for waiting for new events */ +static DECLARE_WAIT_QUEUE_HEAD(uwbd_wq); +/** Daemon's list of events; we queue/dequeue here */ +static struct list_head uwbd_event_list = LIST_HEAD_INIT(uwbd_event_list); +/** Daemon's list lock to protect concurent access */ +static DEFINE_SPINLOCK(uwbd_event_list_lock); + + +/** + * UWB Daemon + * + * Listens to all UWB notifications and takes care to track the state + * of the UWB neighboorhood for the kernel. When we do a run, we + * spinlock, move the list to a private copy and release the + * lock. Hold it as little as possible. Not a conflict: it is + * guaranteed we own the events in the private list. + * + * FIXME: should change so we don't have a 1HZ timer all the time, but + * only if there are devices. + */ +static int uwbd(void *unused) +{ + unsigned long flags; + struct list_head list = LIST_HEAD_INIT(list); + struct uwb_event *evt, *nxt; + int should_stop = 0; + while (1) { + wait_event_interruptible_timeout( + uwbd_wq, + !list_empty(&uwbd_event_list) + || (should_stop = kthread_should_stop()), + HZ); + if (should_stop) + break; + try_to_freeze(); + + mutex_lock(&uwbd_event_mutex); + spin_lock_irqsave(&uwbd_event_list_lock, flags); + list_splice_init(&uwbd_event_list, &list); + spin_unlock_irqrestore(&uwbd_event_list_lock, flags); + list_for_each_entry_safe(evt, nxt, &list, list_node) { + list_del(&evt->list_node); + uwbd_event_handle(evt); + kfree(evt); + } + mutex_unlock(&uwbd_event_mutex); + + uwb_beca_purge(); /* Purge devices that left */ + } + return 0; +} + + +/** Start the UWB daemon */ +void uwbd_start(void) +{ + uwbd_task = kthread_run(uwbd, NULL, "uwbd"); + if (uwbd_task == NULL) + printk(KERN_ERR "UWB: Cannot start management daemon; " + "UWB won't work\n"); + else + uwbd_pid = uwbd_task->pid; +} + +/* Stop the UWB daemon and free any unprocessed events */ +void uwbd_stop(void) +{ + unsigned long flags; + struct uwb_event *evt, *nxt; + kthread_stop(uwbd_task); + spin_lock_irqsave(&uwbd_event_list_lock, flags); + uwbd_pid = 0; + list_for_each_entry_safe(evt, nxt, &uwbd_event_list, list_node) { + if (evt->type == UWB_EVT_TYPE_NOTIF) + kfree(evt->notif.rceb); + kfree(evt); + } + spin_unlock_irqrestore(&uwbd_event_list_lock, flags); + uwb_beca_release(); +} + +/* + * Queue an event for the management daemon + * + * When some lower layer receives an event, it uses this function to + * push it forward to the UWB daemon. + * + * Once you pass the event, you don't own it any more, but the daemon + * does. It will uwb_event_free() it when done, so make sure you + * uwb_event_alloc()ed it or bad things will happen. + * + * If the daemon is not running, we just free the event. + */ +void uwbd_event_queue(struct uwb_event *evt) +{ + unsigned long flags; + spin_lock_irqsave(&uwbd_event_list_lock, flags); + if (uwbd_pid != 0) { + list_add(&evt->list_node, &uwbd_event_list); + wake_up_all(&uwbd_wq); + } else { + __uwb_rc_put(evt->rc); + if (evt->type == UWB_EVT_TYPE_NOTIF) + kfree(evt->notif.rceb); + kfree(evt); + } + spin_unlock_irqrestore(&uwbd_event_list_lock, flags); + return; +} + +void uwbd_flush(struct uwb_rc *rc) +{ + struct uwb_event *evt, *nxt; + + mutex_lock(&uwbd_event_mutex); + + spin_lock_irq(&uwbd_event_list_lock); + list_for_each_entry_safe(evt, nxt, &uwbd_event_list, list_node) { + if (evt->rc == rc) { + __uwb_rc_put(rc); + list_del(&evt->list_node); + if (evt->type == UWB_EVT_TYPE_NOTIF) + kfree(evt->notif.rceb); + kfree(evt); + } + } + spin_unlock_irq(&uwbd_event_list_lock); + + mutex_unlock(&uwbd_event_mutex); +} |