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Inaky Perez-Gonzalez0612edf2008-09-17 16:34:07 +01001/*
2 * WUSB Wire Adapter: Radio Control Interface (WUSB[8])
3 * Notification and Event Handling
4 *
5 * Copyright (C) 2005-2006 Intel Corporation
6 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version
10 * 2 as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
20 * 02110-1301, USA.
21 *
22 *
23 * The RC interface of the Host Wire Adapter (USB dongle) or WHCI PCI
24 * card delivers a stream of notifications and events to the
25 * notification end event endpoint or area. This code takes care of
26 * getting a buffer with that data, breaking it up in separate
27 * notifications and events and then deliver those.
28 *
29 * Events are answers to commands and they carry a context ID that
30 * associates them to the command. Notifications are that,
31 * notifications, they come out of the blue and have a context ID of
32 * zero. Think of the context ID kind of like a handler. The
33 * uwb_rc_neh_* code deals with managing context IDs.
34 *
35 * This is why you require a handle to operate on a UWB host. When you
36 * open a handle a context ID is assigned to you.
37 *
38 * So, as it is done is:
39 *
40 * 1. Add an event handler [uwb_rc_neh_add()] (assigns a ctx id)
41 * 2. Issue command [rc->cmd(rc, ...)]
42 * 3. Arm the timeout timer [uwb_rc_neh_arm()]
43 * 4, Release the reference to the neh [uwb_rc_neh_put()]
44 * 5. Wait for the callback
45 * 6. Command result (RCEB) is passed to the callback
46 *
47 * If (2) fails, you should remove the handle [uwb_rc_neh_rm()]
48 * instead of arming the timer.
49 *
50 * Handles are for using in *serialized* code, single thread.
51 *
52 * When the notification/event comes, the IRQ handler/endpoint
53 * callback passes the data read to uwb_rc_neh_grok() which will break
54 * it up in a discrete series of events, look up who is listening for
55 * them and execute the pertinent callbacks.
56 *
57 * If the reader detects an error while reading the data stream, call
58 * uwb_rc_neh_error().
59 *
60 * CONSTRAINTS/ASSUMPTIONS:
61 *
62 * - Most notifications/events are small (less thank .5k), copying
63 * around is ok.
64 *
65 * - Notifications/events are ALWAYS smaller than PAGE_SIZE
66 *
67 * - Notifications/events always come in a single piece (ie: a buffer
68 * will always contain entire notifications/events).
69 *
70 * - we cannot know in advance how long each event is (because they
71 * lack a length field in their header--smart move by the standards
72 * body, btw). So we need a facility to get the event size given the
73 * header. This is what the EST code does (notif/Event Size
74 * Tables), check nest.c--as well, you can associate the size to
75 * the handle [w/ neh->extra_size()].
76 *
77 * - Most notifications/events are fixed size; only a few are variable
78 * size (NEST takes care of that).
79 *
80 * - Listeners of events expect them, so they usually provide a
81 * buffer, as they know the size. Listeners to notifications don't,
82 * so we allocate their buffers dynamically.
83 */
84#include <linux/kernel.h>
85#include <linux/timer.h>
86#include <linux/err.h>
87
88#include "uwb-internal.h"
89#define D_LOCAL 0
90#include <linux/uwb/debug.h>
91
92/*
93 * UWB Radio Controller Notification/Event Handle
94 *
95 * Represents an entity waiting for an event coming from the UWB Radio
96 * Controller with a given context id (context) and type (evt_type and
97 * evt). On reception of the notification/event, the callback (cb) is
98 * called with the event.
99 *
100 * If the timer expires before the event is received, the callback is
101 * called with -ETIMEDOUT as the event size.
102 */
103struct uwb_rc_neh {
104 struct kref kref;
105
106 struct uwb_rc *rc;
107 u8 evt_type;
108 __le16 evt;
109 u8 context;
110 uwb_rc_cmd_cb_f cb;
111 void *arg;
112
113 struct timer_list timer;
114 struct list_head list_node;
115};
116
117static void uwb_rc_neh_timer(unsigned long arg);
118
119static void uwb_rc_neh_release(struct kref *kref)
120{
121 struct uwb_rc_neh *neh = container_of(kref, struct uwb_rc_neh, kref);
122
123 kfree(neh);
124}
125
126static void uwb_rc_neh_get(struct uwb_rc_neh *neh)
127{
128 kref_get(&neh->kref);
129}
130
131/**
132 * uwb_rc_neh_put - release reference to a neh
133 * @neh: the neh
134 */
135void uwb_rc_neh_put(struct uwb_rc_neh *neh)
136{
137 kref_put(&neh->kref, uwb_rc_neh_release);
138}
139
140
141/**
142 * Assigns @neh a context id from @rc's pool
143 *
144 * @rc: UWB Radio Controller descriptor; @rc->neh_lock taken
145 * @neh: Notification/Event Handle
146 * @returns 0 if context id was assigned ok; < 0 errno on error (if
147 * all the context IDs are taken).
148 *
149 * (assumes @wa is locked).
150 *
151 * NOTE: WUSB spec reserves context ids 0x00 for notifications and
152 * 0xff is invalid, so they must not be used. Initialization
153 * fills up those two in the bitmap so they are not allocated.
154 *
155 * We spread the allocation around to reduce the posiblity of two
156 * consecutive opened @neh's getting the same context ID assigned (to
157 * avoid surprises with late events that timed out long time ago). So
158 * first we search from where @rc->ctx_roll is, if not found, we
159 * search from zero.
160 */
161static
162int __uwb_rc_ctx_get(struct uwb_rc *rc, struct uwb_rc_neh *neh)
163{
164 int result;
165 result = find_next_zero_bit(rc->ctx_bm, UWB_RC_CTX_MAX,
166 rc->ctx_roll++);
167 if (result < UWB_RC_CTX_MAX)
168 goto found;
169 result = find_first_zero_bit(rc->ctx_bm, UWB_RC_CTX_MAX);
170 if (result < UWB_RC_CTX_MAX)
171 goto found;
172 return -ENFILE;
173found:
174 set_bit(result, rc->ctx_bm);
175 neh->context = result;
176 return 0;
177}
178
179
180/** Releases @neh's context ID back to @rc (@rc->neh_lock is locked). */
181static
182void __uwb_rc_ctx_put(struct uwb_rc *rc, struct uwb_rc_neh *neh)
183{
184 struct device *dev = &rc->uwb_dev.dev;
185 if (neh->context == 0)
186 return;
187 if (test_bit(neh->context, rc->ctx_bm) == 0) {
188 dev_err(dev, "context %u not set in bitmap\n",
189 neh->context);
190 WARN_ON(1);
191 }
192 clear_bit(neh->context, rc->ctx_bm);
193 neh->context = 0;
194}
195
196/**
197 * uwb_rc_neh_add - add a neh for a radio controller command
198 * @rc: the radio controller
199 * @cmd: the radio controller command
200 * @expected_type: the type of the expected response event
201 * @expected_event: the expected event ID
202 * @cb: callback for when the event is received
203 * @arg: argument for the callback
204 *
205 * Creates a neh and adds it to the list of those waiting for an
206 * event. A context ID will be assigned to the command.
207 */
208struct uwb_rc_neh *uwb_rc_neh_add(struct uwb_rc *rc, struct uwb_rccb *cmd,
209 u8 expected_type, u16 expected_event,
210 uwb_rc_cmd_cb_f cb, void *arg)
211{
212 int result;
213 unsigned long flags;
214 struct device *dev = &rc->uwb_dev.dev;
215 struct uwb_rc_neh *neh;
216
217 neh = kzalloc(sizeof(*neh), GFP_KERNEL);
218 if (neh == NULL) {
219 result = -ENOMEM;
220 goto error_kzalloc;
221 }
222
223 kref_init(&neh->kref);
224 INIT_LIST_HEAD(&neh->list_node);
225 init_timer(&neh->timer);
226 neh->timer.function = uwb_rc_neh_timer;
227 neh->timer.data = (unsigned long)neh;
228
229 neh->rc = rc;
230 neh->evt_type = expected_type;
231 neh->evt = cpu_to_le16(expected_event);
232 neh->cb = cb;
233 neh->arg = arg;
234
235 spin_lock_irqsave(&rc->neh_lock, flags);
236 result = __uwb_rc_ctx_get(rc, neh);
237 if (result >= 0) {
238 cmd->bCommandContext = neh->context;
239 list_add_tail(&neh->list_node, &rc->neh_list);
240 uwb_rc_neh_get(neh);
241 }
242 spin_unlock_irqrestore(&rc->neh_lock, flags);
243 if (result < 0)
244 goto error_ctx_get;
245
246 return neh;
247
248error_ctx_get:
249 kfree(neh);
250error_kzalloc:
251 dev_err(dev, "cannot open handle to radio controller: %d\n", result);
252 return ERR_PTR(result);
253}
254
255static void __uwb_rc_neh_rm(struct uwb_rc *rc, struct uwb_rc_neh *neh)
256{
257 del_timer(&neh->timer);
258 __uwb_rc_ctx_put(rc, neh);
259 list_del(&neh->list_node);
260}
261
262/**
263 * uwb_rc_neh_rm - remove a neh.
264 * @rc: the radio controller
265 * @neh: the neh to remove
266 *
267 * Remove an active neh immediately instead of waiting for the event
268 * (or a time out).
269 */
270void uwb_rc_neh_rm(struct uwb_rc *rc, struct uwb_rc_neh *neh)
271{
272 unsigned long flags;
273
274 spin_lock_irqsave(&rc->neh_lock, flags);
275 __uwb_rc_neh_rm(rc, neh);
276 spin_unlock_irqrestore(&rc->neh_lock, flags);
277
278 uwb_rc_neh_put(neh);
279}
280
281/**
282 * uwb_rc_neh_arm - arm an event handler timeout timer
283 *
284 * @rc: UWB Radio Controller
285 * @neh: Notification/event handler for @rc
286 *
287 * The timer is only armed if the neh is active.
288 */
289void uwb_rc_neh_arm(struct uwb_rc *rc, struct uwb_rc_neh *neh)
290{
291 unsigned long flags;
292
293 spin_lock_irqsave(&rc->neh_lock, flags);
294 if (neh->context)
295 mod_timer(&neh->timer,
296 jiffies + msecs_to_jiffies(UWB_RC_CMD_TIMEOUT_MS));
297 spin_unlock_irqrestore(&rc->neh_lock, flags);
298}
299
300static void uwb_rc_neh_cb(struct uwb_rc_neh *neh, struct uwb_rceb *rceb, size_t size)
301{
302 (*neh->cb)(neh->rc, neh->arg, rceb, size);
303 uwb_rc_neh_put(neh);
304}
305
306static bool uwb_rc_neh_match(struct uwb_rc_neh *neh, const struct uwb_rceb *rceb)
307{
308 return neh->evt_type == rceb->bEventType
309 && neh->evt == rceb->wEvent
310 && neh->context == rceb->bEventContext;
311}
312
313/**
314 * Find the handle waiting for a RC Radio Control Event
315 *
316 * @rc: UWB Radio Controller
317 * @rceb: Pointer to the RCEB buffer
318 * @event_size: Pointer to the size of the RCEB buffer. Might be
319 * adjusted to take into account the @neh->extra_size
320 * settings.
321 *
322 * If the listener has no buffer (NULL buffer), one is allocated for
323 * the right size (the amount of data received). @neh->ptr will point
324 * to the event payload, which always starts with a 'struct
325 * uwb_rceb'. kfree() it when done.
326 */
327static
328struct uwb_rc_neh *uwb_rc_neh_lookup(struct uwb_rc *rc,
329 const struct uwb_rceb *rceb)
330{
331 struct uwb_rc_neh *neh = NULL, *h;
332 unsigned long flags;
333
334 spin_lock_irqsave(&rc->neh_lock, flags);
335
336 list_for_each_entry(h, &rc->neh_list, list_node) {
337 if (uwb_rc_neh_match(h, rceb)) {
338 neh = h;
339 break;
340 }
341 }
342
343 if (neh)
344 __uwb_rc_neh_rm(rc, neh);
345
346 spin_unlock_irqrestore(&rc->neh_lock, flags);
347
348 return neh;
349}
350
351
352/**
353 * Process notifications coming from the radio control interface
354 *
355 * @rc: UWB Radio Control Interface descriptor
356 * @neh: Notification/Event Handler @neh->ptr points to
357 * @uwb_evt->buffer.
358 *
359 * This function is called by the event/notif handling subsystem when
360 * notifications arrive (hwarc_probe() arms a notification/event handle
361 * that calls back this function for every received notification; this
362 * function then will rearm itself).
363 *
364 * Notification data buffers are dynamically allocated by the NEH
365 * handling code in neh.c [uwb_rc_neh_lookup()]. What is actually
366 * allocated is space to contain the notification data.
367 *
368 * Buffers are prefixed with a Radio Control Event Block (RCEB) as
369 * defined by the WUSB Wired-Adapter Radio Control interface. We
370 * just use it for the notification code.
371 *
372 * On each case statement we just transcode endianess of the different
373 * fields. We declare a pointer to a RCI definition of an event, and
374 * then to a UWB definition of the same event (which are the same,
375 * remember). Event if we use different pointers
376 */
377static
378void uwb_rc_notif(struct uwb_rc *rc, struct uwb_rceb *rceb, ssize_t size)
379{
380 struct device *dev = &rc->uwb_dev.dev;
381 struct uwb_event *uwb_evt;
382
383 if (size == -ESHUTDOWN)
384 return;
385 if (size < 0) {
386 dev_err(dev, "ignoring event with error code %zu\n",
387 size);
388 return;
389 }
390
391 uwb_evt = kzalloc(sizeof(*uwb_evt), GFP_ATOMIC);
392 if (unlikely(uwb_evt == NULL)) {
393 dev_err(dev, "no memory to queue event 0x%02x/%04x/%02x\n",
394 rceb->bEventType, le16_to_cpu(rceb->wEvent),
395 rceb->bEventContext);
396 return;
397 }
398 uwb_evt->rc = __uwb_rc_get(rc); /* will be put by uwbd's uwbd_event_handle() */
399 uwb_evt->ts_jiffies = jiffies;
400 uwb_evt->type = UWB_EVT_TYPE_NOTIF;
401 uwb_evt->notif.size = size;
402 uwb_evt->notif.rceb = rceb;
403
404 switch (le16_to_cpu(rceb->wEvent)) {
405 /* Trap some vendor specific events
406 *
407 * FIXME: move this to handling in ptc-est, where we
408 * register a NULL event handler for these two guys
409 * using the Intel IDs.
410 */
411 case 0x0103:
412 dev_info(dev, "FIXME: DEVICE ADD\n");
413 return;
414 case 0x0104:
415 dev_info(dev, "FIXME: DEVICE RM\n");
416 return;
417 default:
418 break;
419 }
420
421 uwbd_event_queue(uwb_evt);
422}
423
424static void uwb_rc_neh_grok_event(struct uwb_rc *rc, struct uwb_rceb *rceb, size_t size)
425{
426 struct device *dev = &rc->uwb_dev.dev;
427 struct uwb_rc_neh *neh;
428 struct uwb_rceb *notif;
429
430 if (rceb->bEventContext == 0) {
431 notif = kmalloc(size, GFP_ATOMIC);
432 if (notif) {
433 memcpy(notif, rceb, size);
434 uwb_rc_notif(rc, notif, size);
435 } else
436 dev_err(dev, "event 0x%02x/%04x/%02x (%zu bytes): no memory\n",
437 rceb->bEventType, le16_to_cpu(rceb->wEvent),
438 rceb->bEventContext, size);
439 } else {
440 neh = uwb_rc_neh_lookup(rc, rceb);
441 if (neh)
442 uwb_rc_neh_cb(neh, rceb, size);
David Vrabel8092d7c2008-10-16 13:56:53 +0100443 else
Inaky Perez-Gonzalez0612edf2008-09-17 16:34:07 +0100444 dev_warn(dev, "event 0x%02x/%04x/%02x (%zu bytes): nobody cared\n",
445 rceb->bEventType, le16_to_cpu(rceb->wEvent),
446 rceb->bEventContext, size);
447 }
448}
449
450/**
451 * Given a buffer with one or more UWB RC events/notifications, break
452 * them up and dispatch them.
453 *
454 * @rc: UWB Radio Controller
455 * @buf: Buffer with the stream of notifications/events
456 * @buf_size: Amount of data in the buffer
457 *
458 * Note each notification/event starts always with a 'struct
459 * uwb_rceb', so the minimum size if 4 bytes.
460 *
461 * The device may pass us events formatted differently than expected.
462 * These are first filtered, potentially creating a new event in a new
463 * memory location. If a new event is created by the filter it is also
464 * freed here.
465 *
466 * For each notif/event, tries to guess the size looking at the EST
467 * tables, then looks for a neh that is waiting for that event and if
468 * found, copies the payload to the neh's buffer and calls it back. If
469 * not, the data is ignored.
470 *
471 * Note that if we can't find a size description in the EST tables, we
472 * still might find a size in the 'neh' handle in uwb_rc_neh_lookup().
473 *
474 * Assumptions:
475 *
476 * @rc->neh_lock is NOT taken
477 *
478 * We keep track of various sizes here:
479 * size: contains the size of the buffer that is processed for the
480 * incoming event. this buffer may contain events that are not
481 * formatted as WHCI.
482 * real_size: the actual space taken by this event in the buffer.
483 * We need to keep track of the real size of an event to be able to
484 * advance the buffer correctly.
485 * event_size: the size of the event as expected by the core layer
486 * [OR] the size of the event after filtering. if the filtering
487 * created a new event in a new memory location then this is
488 * effectively the size of a new event buffer
489 */
490void uwb_rc_neh_grok(struct uwb_rc *rc, void *buf, size_t buf_size)
491{
492 struct device *dev = &rc->uwb_dev.dev;
493 void *itr;
494 struct uwb_rceb *rceb;
495 size_t size, real_size, event_size;
496 int needtofree;
497
498 d_fnstart(3, dev, "(rc %p buf %p %zu buf_size)\n", rc, buf, buf_size);
499 d_printf(2, dev, "groking event block: %zu bytes\n", buf_size);
500 itr = buf;
501 size = buf_size;
502 while (size > 0) {
503 if (size < sizeof(*rceb)) {
504 dev_err(dev, "not enough data in event buffer to "
505 "process incoming events (%zu left, minimum is "
506 "%zu)\n", size, sizeof(*rceb));
507 break;
508 }
509
510 rceb = itr;
511 if (rc->filter_event) {
512 needtofree = rc->filter_event(rc, &rceb, size,
513 &real_size, &event_size);
514 if (needtofree < 0 && needtofree != -ENOANO) {
515 dev_err(dev, "BUG: Unable to filter event "
516 "(0x%02x/%04x/%02x) from "
517 "device. \n", rceb->bEventType,
518 le16_to_cpu(rceb->wEvent),
519 rceb->bEventContext);
520 break;
521 }
522 } else
523 needtofree = -ENOANO;
524 /* do real processing if there was no filtering or the
525 * filtering didn't act */
526 if (needtofree == -ENOANO) {
527 ssize_t ret = uwb_est_find_size(rc, rceb, size);
528 if (ret < 0)
529 break;
530 if (ret > size) {
531 dev_err(dev, "BUG: hw sent incomplete event "
532 "0x%02x/%04x/%02x (%zd bytes), only got "
533 "%zu bytes. We don't handle that.\n",
534 rceb->bEventType, le16_to_cpu(rceb->wEvent),
535 rceb->bEventContext, ret, size);
536 break;
537 }
538 real_size = event_size = ret;
539 }
540 uwb_rc_neh_grok_event(rc, rceb, event_size);
541
542 if (needtofree == 1)
543 kfree(rceb);
544
545 itr += real_size;
546 size -= real_size;
547 d_printf(2, dev, "consumed %zd bytes, %zu left\n",
548 event_size, size);
549 }
550 d_fnend(3, dev, "(rc %p buf %p %zu buf_size) = void\n", rc, buf, buf_size);
551}
552EXPORT_SYMBOL_GPL(uwb_rc_neh_grok);
553
554
555/**
556 * The entity that reads from the device notification/event channel has
557 * detected an error.
558 *
559 * @rc: UWB Radio Controller
560 * @error: Errno error code
561 *
562 */
563void uwb_rc_neh_error(struct uwb_rc *rc, int error)
564{
565 struct uwb_rc_neh *neh, *next;
566 unsigned long flags;
567
568 BUG_ON(error >= 0);
569 spin_lock_irqsave(&rc->neh_lock, flags);
570 list_for_each_entry_safe(neh, next, &rc->neh_list, list_node) {
571 __uwb_rc_neh_rm(rc, neh);
572 uwb_rc_neh_cb(neh, NULL, error);
573 }
574 spin_unlock_irqrestore(&rc->neh_lock, flags);
575}
576EXPORT_SYMBOL_GPL(uwb_rc_neh_error);
577
578
579static void uwb_rc_neh_timer(unsigned long arg)
580{
581 struct uwb_rc_neh *neh = (struct uwb_rc_neh *)arg;
582 struct uwb_rc *rc = neh->rc;
583 unsigned long flags;
584
585 spin_lock_irqsave(&rc->neh_lock, flags);
586 __uwb_rc_neh_rm(rc, neh);
587 spin_unlock_irqrestore(&rc->neh_lock, flags);
588
589 uwb_rc_neh_cb(neh, NULL, -ETIMEDOUT);
590}
591
592/** Initializes the @rc's neh subsystem
593 */
594void uwb_rc_neh_create(struct uwb_rc *rc)
595{
596 spin_lock_init(&rc->neh_lock);
597 INIT_LIST_HEAD(&rc->neh_list);
598 set_bit(0, rc->ctx_bm); /* 0 is reserved (see [WUSB] table 8-65) */
599 set_bit(0xff, rc->ctx_bm); /* and 0xff is invalid */
600 rc->ctx_roll = 1;
601}
602
603
604/** Release's the @rc's neh subsystem */
605void uwb_rc_neh_destroy(struct uwb_rc *rc)
606{
607 unsigned long flags;
608 struct uwb_rc_neh *neh, *next;
609
610 spin_lock_irqsave(&rc->neh_lock, flags);
611 list_for_each_entry_safe(neh, next, &rc->neh_list, list_node) {
612 __uwb_rc_neh_rm(rc, neh);
613 uwb_rc_neh_put(neh);
614 }
615 spin_unlock_irqrestore(&rc->neh_lock, flags);
616}