/*
* 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);
}
