1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
|
/*
* 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"
/*
* 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_urc_events[] = {
[UWB_RC_EVT_IE_RCV] = {
.handler = uwbd_evt_handle_rc_ie_rcv,
.name = "IE_RECEIVED"
},
[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;
};
/* Table of handlers for each UWBD Event type. */
static struct uwbd_evt_type_handler uwbd_urc_evt_type_handlers[] = {
[UWB_RC_CET_GENERAL] = {
.name = "URC",
.uwbd_events = uwbd_urc_events,
.size = ARRAY_SIZE(uwbd_urc_events),
},
};
static const struct uwbd_event uwbd_message_handlers[] = {
[UWB_EVT_MSG_RESET] = {
.handler = uwbd_msg_handle_reset,
.name = "reset",
},
};
/*
* 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)
{
int result = -EINVAL;
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 >= ARRAY_SIZE(uwbd_urc_evt_type_handlers))
goto out;
type_table = &uwbd_urc_evt_type_handlers[type];
if (type_table->uwbd_events == NULL)
goto out;
if (event >= type_table->size)
goto out;
handler = type_table->uwbd_events[event].handler;
if (handler == NULL)
goto out;
result = (*handler)(evt);
out:
if (result < 0)
dev_err(&evt->rc->uwb_dev.dev,
"UWBD: event 0x%02x/%04x/%02x, handling failed: %d\n",
type, event, context, result);
return result;
}
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;
}
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);
}
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() */
}
/**
* 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 *param)
{
struct uwb_rc *rc = param;
unsigned long flags;
struct uwb_event *evt;
int should_stop = 0;
while (1) {
wait_event_interruptible_timeout(
rc->uwbd.wq,
!list_empty(&rc->uwbd.event_list)
|| (should_stop = kthread_should_stop()),
HZ);
if (should_stop)
break;
try_to_freeze();
spin_lock_irqsave(&rc->uwbd.event_list_lock, flags);
if (!list_empty(&rc->uwbd.event_list)) {
evt = list_first_entry(&rc->uwbd.event_list, struct uwb_event, list_node);
list_del(&evt->list_node);
} else
evt = NULL;
spin_unlock_irqrestore(&rc->uwbd.event_list_lock, flags);
if (evt) {
uwbd_event_handle(evt);
kfree(evt);
}
uwb_beca_purge(rc); /* Purge devices that left */
}
return 0;
}
/** Start the UWB daemon */
void uwbd_start(struct uwb_rc *rc)
{
rc->uwbd.task = kthread_run(uwbd, rc, "uwbd");
if (rc->uwbd.task == NULL)
printk(KERN_ERR "UWB: Cannot start management daemon; "
"UWB won't work\n");
else
rc->uwbd.pid = rc->uwbd.task->pid;
}
/* Stop the UWB daemon and free any unprocessed events */
void uwbd_stop(struct uwb_rc *rc)
{
kthread_stop(rc->uwbd.task);
uwbd_flush(rc);
}
/*
* 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)
{
struct uwb_rc *rc = evt->rc;
unsigned long flags;
spin_lock_irqsave(&rc->uwbd.event_list_lock, flags);
if (rc->uwbd.pid != 0) {
list_add(&evt->list_node, &rc->uwbd.event_list);
wake_up_all(&rc->uwbd.wq);
} else {
__uwb_rc_put(evt->rc);
if (evt->type == UWB_EVT_TYPE_NOTIF)
kfree(evt->notif.rceb);
kfree(evt);
|