Add linux-next specific files for 20110831
[linux-2.6/next.git] / drivers / uwb / neh.c
bloba269937be1b8230898f991eb5f430e3f79ac9824
1 /*
2 * WUSB Wire Adapter: Radio Control Interface (WUSB[8])
3 * Notification and Event Handling
5 * Copyright (C) 2005-2006 Intel Corporation
6 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
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.
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.
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.
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.
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.
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.
38 * So, as it is done is:
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
47 * If (2) fails, you should remove the handle [uwb_rc_neh_rm()]
48 * instead of arming the timer.
50 * Handles are for using in *serialized* code, single thread.
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.
57 * If the reader detects an error while reading the data stream, call
58 * uwb_rc_neh_error().
60 * CONSTRAINTS/ASSUMPTIONS:
62 * - Most notifications/events are small (less thank .5k), copying
63 * around is ok.
65 * - Notifications/events are ALWAYS smaller than PAGE_SIZE
67 * - Notifications/events always come in a single piece (ie: a buffer
68 * will always contain entire notifications/events).
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()].
77 * - Most notifications/events are fixed size; only a few are variable
78 * size (NEST takes care of that).
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.
84 #include <linux/kernel.h>
85 #include <linux/timer.h>
86 #include <linux/slab.h>
87 #include <linux/err.h>
88 #include <linux/export.h>
90 #include "uwb-internal.h"
93 * UWB Radio Controller Notification/Event Handle
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.
100 * If the timer expires before the event is received, the callback is
101 * called with -ETIMEDOUT as the event size.
103 struct uwb_rc_neh {
104 struct kref kref;
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;
113 struct timer_list timer;
114 struct list_head list_node;
117 static void uwb_rc_neh_timer(unsigned long arg);
119 static void uwb_rc_neh_release(struct kref *kref)
121 struct uwb_rc_neh *neh = container_of(kref, struct uwb_rc_neh, kref);
123 kfree(neh);
126 static void uwb_rc_neh_get(struct uwb_rc_neh *neh)
128 kref_get(&neh->kref);
132 * uwb_rc_neh_put - release reference to a neh
133 * @neh: the neh
135 void uwb_rc_neh_put(struct uwb_rc_neh *neh)
137 kref_put(&neh->kref, uwb_rc_neh_release);
142 * Assigns @neh a context id from @rc's pool
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).
149 * (assumes @wa is locked).
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.
155 * We spread the allocation around to reduce the possibility 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.
161 static
162 int __uwb_rc_ctx_get(struct uwb_rc *rc, struct uwb_rc_neh *neh)
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;
173 found:
174 set_bit(result, rc->ctx_bm);
175 neh->context = result;
176 return 0;
180 /** Releases @neh's context ID back to @rc (@rc->neh_lock is locked). */
181 static
182 void __uwb_rc_ctx_put(struct uwb_rc *rc, struct uwb_rc_neh *neh)
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);
192 clear_bit(neh->context, rc->ctx_bm);
193 neh->context = 0;
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
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.
208 struct 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)
212 int result;
213 unsigned long flags;
214 struct device *dev = &rc->uwb_dev.dev;
215 struct uwb_rc_neh *neh;
217 neh = kzalloc(sizeof(*neh), GFP_KERNEL);
218 if (neh == NULL) {
219 result = -ENOMEM;
220 goto error_kzalloc;
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;
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;
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);
242 spin_unlock_irqrestore(&rc->neh_lock, flags);
243 if (result < 0)
244 goto error_ctx_get;
246 return neh;
248 error_ctx_get:
249 kfree(neh);
250 error_kzalloc:
251 dev_err(dev, "cannot open handle to radio controller: %d\n", result);
252 return ERR_PTR(result);
255 static void __uwb_rc_neh_rm(struct uwb_rc *rc, struct uwb_rc_neh *neh)
257 __uwb_rc_ctx_put(rc, neh);
258 list_del(&neh->list_node);
262 * uwb_rc_neh_rm - remove a neh.
263 * @rc: the radio controller
264 * @neh: the neh to remove
266 * Remove an active neh immediately instead of waiting for the event
267 * (or a time out).
269 void uwb_rc_neh_rm(struct uwb_rc *rc, struct uwb_rc_neh *neh)
271 unsigned long flags;
273 spin_lock_irqsave(&rc->neh_lock, flags);
274 __uwb_rc_neh_rm(rc, neh);
275 spin_unlock_irqrestore(&rc->neh_lock, flags);
277 del_timer_sync(&neh->timer);
278 uwb_rc_neh_put(neh);
282 * uwb_rc_neh_arm - arm an event handler timeout timer
284 * @rc: UWB Radio Controller
285 * @neh: Notification/event handler for @rc
287 * The timer is only armed if the neh is active.
289 void uwb_rc_neh_arm(struct uwb_rc *rc, struct uwb_rc_neh *neh)
291 unsigned long flags;
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);
300 static void uwb_rc_neh_cb(struct uwb_rc_neh *neh, struct uwb_rceb *rceb, size_t size)
302 (*neh->cb)(neh->rc, neh->arg, rceb, size);
303 uwb_rc_neh_put(neh);
306 static bool uwb_rc_neh_match(struct uwb_rc_neh *neh, const struct uwb_rceb *rceb)
308 return neh->evt_type == rceb->bEventType
309 && neh->evt == rceb->wEvent
310 && neh->context == rceb->bEventContext;
314 * Find the handle waiting for a RC Radio Control Event
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.
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.
327 static
328 struct uwb_rc_neh *uwb_rc_neh_lookup(struct uwb_rc *rc,
329 const struct uwb_rceb *rceb)
331 struct uwb_rc_neh *neh = NULL, *h;
332 unsigned long flags;
334 spin_lock_irqsave(&rc->neh_lock, flags);
336 list_for_each_entry(h, &rc->neh_list, list_node) {
337 if (uwb_rc_neh_match(h, rceb)) {
338 neh = h;
339 break;
343 if (neh)
344 __uwb_rc_neh_rm(rc, neh);
346 spin_unlock_irqrestore(&rc->neh_lock, flags);
348 return neh;
353 * Process notifications coming from the radio control interface
355 * @rc: UWB Radio Control Interface descriptor
356 * @neh: Notification/Event Handler @neh->ptr points to
357 * @uwb_evt->buffer.
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).
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.
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.
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
377 static
378 void uwb_rc_notif(struct uwb_rc *rc, struct uwb_rceb *rceb, ssize_t size)
380 struct device *dev = &rc->uwb_dev.dev;
381 struct uwb_event *uwb_evt;
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;
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;
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;
404 uwbd_event_queue(uwb_evt);
407 static void uwb_rc_neh_grok_event(struct uwb_rc *rc, struct uwb_rceb *rceb, size_t size)
409 struct device *dev = &rc->uwb_dev.dev;
410 struct uwb_rc_neh *neh;
411 struct uwb_rceb *notif;
413 if (rceb->bEventContext == 0) {
414 notif = kmalloc(size, GFP_ATOMIC);
415 if (notif) {
416 memcpy(notif, rceb, size);
417 uwb_rc_notif(rc, notif, size);
418 } else
419 dev_err(dev, "event 0x%02x/%04x/%02x (%zu bytes): no memory\n",
420 rceb->bEventType, le16_to_cpu(rceb->wEvent),
421 rceb->bEventContext, size);
422 } else {
423 neh = uwb_rc_neh_lookup(rc, rceb);
424 if (neh) {
425 del_timer_sync(&neh->timer);
426 uwb_rc_neh_cb(neh, rceb, size);
427 } else
428 dev_warn(dev, "event 0x%02x/%04x/%02x (%zu bytes): nobody cared\n",
429 rceb->bEventType, le16_to_cpu(rceb->wEvent),
430 rceb->bEventContext, size);
435 * Given a buffer with one or more UWB RC events/notifications, break
436 * them up and dispatch them.
438 * @rc: UWB Radio Controller
439 * @buf: Buffer with the stream of notifications/events
440 * @buf_size: Amount of data in the buffer
442 * Note each notification/event starts always with a 'struct
443 * uwb_rceb', so the minimum size if 4 bytes.
445 * The device may pass us events formatted differently than expected.
446 * These are first filtered, potentially creating a new event in a new
447 * memory location. If a new event is created by the filter it is also
448 * freed here.
450 * For each notif/event, tries to guess the size looking at the EST
451 * tables, then looks for a neh that is waiting for that event and if
452 * found, copies the payload to the neh's buffer and calls it back. If
453 * not, the data is ignored.
455 * Note that if we can't find a size description in the EST tables, we
456 * still might find a size in the 'neh' handle in uwb_rc_neh_lookup().
458 * Assumptions:
460 * @rc->neh_lock is NOT taken
462 * We keep track of various sizes here:
463 * size: contains the size of the buffer that is processed for the
464 * incoming event. this buffer may contain events that are not
465 * formatted as WHCI.
466 * real_size: the actual space taken by this event in the buffer.
467 * We need to keep track of the real size of an event to be able to
468 * advance the buffer correctly.
469 * event_size: the size of the event as expected by the core layer
470 * [OR] the size of the event after filtering. if the filtering
471 * created a new event in a new memory location then this is
472 * effectively the size of a new event buffer
474 void uwb_rc_neh_grok(struct uwb_rc *rc, void *buf, size_t buf_size)
476 struct device *dev = &rc->uwb_dev.dev;
477 void *itr;
478 struct uwb_rceb *rceb;
479 size_t size, real_size, event_size;
480 int needtofree;
482 itr = buf;
483 size = buf_size;
484 while (size > 0) {
485 if (size < sizeof(*rceb)) {
486 dev_err(dev, "not enough data in event buffer to "
487 "process incoming events (%zu left, minimum is "
488 "%zu)\n", size, sizeof(*rceb));
489 break;
492 rceb = itr;
493 if (rc->filter_event) {
494 needtofree = rc->filter_event(rc, &rceb, size,
495 &real_size, &event_size);
496 if (needtofree < 0 && needtofree != -ENOANO) {
497 dev_err(dev, "BUG: Unable to filter event "
498 "(0x%02x/%04x/%02x) from "
499 "device. \n", rceb->bEventType,
500 le16_to_cpu(rceb->wEvent),
501 rceb->bEventContext);
502 break;
504 } else
505 needtofree = -ENOANO;
506 /* do real processing if there was no filtering or the
507 * filtering didn't act */
508 if (needtofree == -ENOANO) {
509 ssize_t ret = uwb_est_find_size(rc, rceb, size);
510 if (ret < 0)
511 break;
512 if (ret > size) {
513 dev_err(dev, "BUG: hw sent incomplete event "
514 "0x%02x/%04x/%02x (%zd bytes), only got "
515 "%zu bytes. We don't handle that.\n",
516 rceb->bEventType, le16_to_cpu(rceb->wEvent),
517 rceb->bEventContext, ret, size);
518 break;
520 real_size = event_size = ret;
522 uwb_rc_neh_grok_event(rc, rceb, event_size);
524 if (needtofree == 1)
525 kfree(rceb);
527 itr += real_size;
528 size -= real_size;
531 EXPORT_SYMBOL_GPL(uwb_rc_neh_grok);
535 * The entity that reads from the device notification/event channel has
536 * detected an error.
538 * @rc: UWB Radio Controller
539 * @error: Errno error code
542 void uwb_rc_neh_error(struct uwb_rc *rc, int error)
544 struct uwb_rc_neh *neh;
545 unsigned long flags;
547 for (;;) {
548 spin_lock_irqsave(&rc->neh_lock, flags);
549 if (list_empty(&rc->neh_list)) {
550 spin_unlock_irqrestore(&rc->neh_lock, flags);
551 break;
553 neh = list_first_entry(&rc->neh_list, struct uwb_rc_neh, list_node);
554 __uwb_rc_neh_rm(rc, neh);
555 spin_unlock_irqrestore(&rc->neh_lock, flags);
557 del_timer_sync(&neh->timer);
558 uwb_rc_neh_cb(neh, NULL, error);
561 EXPORT_SYMBOL_GPL(uwb_rc_neh_error);
564 static void uwb_rc_neh_timer(unsigned long arg)
566 struct uwb_rc_neh *neh = (struct uwb_rc_neh *)arg;
567 struct uwb_rc *rc = neh->rc;
568 unsigned long flags;
570 spin_lock_irqsave(&rc->neh_lock, flags);
571 if (neh->context)
572 __uwb_rc_neh_rm(rc, neh);
573 else
574 neh = NULL;
575 spin_unlock_irqrestore(&rc->neh_lock, flags);
577 if (neh)
578 uwb_rc_neh_cb(neh, NULL, -ETIMEDOUT);
581 /** Initializes the @rc's neh subsystem
583 void uwb_rc_neh_create(struct uwb_rc *rc)
585 spin_lock_init(&rc->neh_lock);
586 INIT_LIST_HEAD(&rc->neh_list);
587 set_bit(0, rc->ctx_bm); /* 0 is reserved (see [WUSB] table 8-65) */
588 set_bit(0xff, rc->ctx_bm); /* and 0xff is invalid */
589 rc->ctx_roll = 1;
593 /** Release's the @rc's neh subsystem */
594 void uwb_rc_neh_destroy(struct uwb_rc *rc)
596 unsigned long flags;
597 struct uwb_rc_neh *neh;
599 for (;;) {
600 spin_lock_irqsave(&rc->neh_lock, flags);
601 if (list_empty(&rc->neh_list)) {
602 spin_unlock_irqrestore(&rc->neh_lock, flags);
603 break;
605 neh = list_first_entry(&rc->neh_list, struct uwb_rc_neh, list_node);
606 __uwb_rc_neh_rm(rc, neh);
607 spin_unlock_irqrestore(&rc->neh_lock, flags);
609 del_timer_sync(&neh->timer);
610 uwb_rc_neh_put(neh);