1 /* $FreeBSD: head/sys/dev/usb/usb_process.c 267992 2014-06-28 03:56:17Z hselasky $ */
2 /*-
3 * Copyright (c) 2008 Hans Petter Selasky. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #define USB_DEBUG_VAR usb_proc_debug
28
29 #include <sys/stdint.h>
30 #include <sys/param.h>
31 #include <sys/queue.h>
32 #include <sys/types.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
35 #include <sys/bus.h>
36 #include <sys/module.h>
37 #include <sys/lock.h>
38 #include <sys/condvar.h>
39 #include <sys/sysctl.h>
40 #include <sys/unistd.h>
41 #include <sys/callout.h>
42 #include <sys/malloc.h>
43 #include <sys/caps.h>
44
45 #include <bus/u4b/usb.h>
46 #include <bus/u4b/usbdi.h>
47 #include <bus/u4b/usbdi_util.h>
48 #include <bus/u4b/usb_process.h>
49 #include <bus/u4b/usb_debug.h>
50 #include <bus/u4b/usb_util.h>
51
52 #include <sys/proc.h>
53 #include <sys/kthread.h>
54 #include <sys/sched.h>
55
56 static struct proc *usbproc;
57 static int usb_pcount;
58 #define USB_THREAD_CREATE(f, s, p, ...) \
59 kthread_create((f), (s), (p), __VA_ARGS__)
60 #define USB_THREAD_SUSPEND_CHECK() kthread_suspend_check(curproc)
61 #define USB_THREAD_SUSPEND(p) suspend_kproc(p,0)
62 #define USB_THREAD_EXIT(err) kthread_exit()
63
64 #ifdef USB_DEBUG
65 static int usb_proc_debug;
66
67 static SYSCTL_NODE(_hw_usb, OID_AUTO, proc, CTLFLAG_RW, 0, "USB process");
68 SYSCTL_INT(_hw_usb_proc, OID_AUTO, debug, CTLFLAG_RW, &usb_proc_debug, 0,
69 "Debug level");
70
71 TUNABLE_INT("hw.usb.proc.debug", &usb_proc_debug);
72 #endif
73
74 /*------------------------------------------------------------------------*
75 * usb_process
76 *
77 * This function is the USB process dispatcher.
78 *------------------------------------------------------------------------*/
79 static void
usb_process(void * arg)80 usb_process(void *arg)
81 {
82 struct usb_process *up = arg;
83 struct usb_proc_msg *pm;
84 struct thread *td;
85
86 #if 0 /* XXX Suspend here? */
87 /* in case of attach error, check for suspended */
88 USB_THREAD_SUSPEND_CHECK();
89 #endif
90
91 /* adjust priority */
92 td = curthread;
93 lwkt_setpri(td, up->up_prio);
94 lockmgr(up->up_lock, LK_EXCLUSIVE);
95
96 up->up_curtd = td;
97
98 while (1) {
99
100 if (up->up_gone)
101 break;
102
103 /*
104 * NOTE to reimplementors: dequeueing a command from the
105 * "used" queue and executing it must be atomic, with regard
106 * to the "up_mtx" mutex. That means any attempt to queue a
107 * command by another thread must be blocked until either:
108 *
109 * 1) the command sleeps
110 *
111 * 2) the command returns
112 *
113 * Here is a practical example that shows how this helps
114 * solving a problem:
115 *
116 * Assume that you want to set the baud rate on a USB serial
117 * device. During the programming of the device you don't
118 * want to receive nor transmit any data, because it will be
119 * garbage most likely anyway. The programming of our USB
120 * device takes 20 milliseconds and it needs to call
121 * functions that sleep.
122 *
123 * Non-working solution: Before we queue the programming
124 * command, we stop transmission and reception of data. Then
125 * we queue a programming command. At the end of the
126 * programming command we enable transmission and reception
127 * of data.
128 *
129 * Problem: If a second programming command is queued while the
130 * first one is sleeping, we end up enabling transmission
131 * and reception of data too early.
132 *
133 * Working solution: Before we queue the programming command,
134 * we stop transmission and reception of data. Then we queue
135 * a programming command. Then we queue a second command
136 * that only enables transmission and reception of data.
137 *
138 * Why it works: If a second programming command is queued
139 * while the first one is sleeping, then the queueing of a
140 * second command to enable the data transfers, will cause
141 * the previous one, which is still on the queue, to be
142 * removed from the queue, and re-inserted after the last
143 * baud rate programming command, which then gives the
144 * desired result.
145 */
146 pm = TAILQ_FIRST(&up->up_qhead);
147
148 if (pm) {
149 DPRINTF("Message pm=%p, cb=%p (enter)\n",
150 pm, pm->pm_callback);
151
152 (pm->pm_callback) (pm);
153
154 if (pm == TAILQ_FIRST(&up->up_qhead)) {
155 /* nothing changed */
156 TAILQ_REMOVE(&up->up_qhead, pm, pm_qentry);
157 pm->pm_qentry.tqe_prev = NULL;
158 }
159 DPRINTF("Message pm=%p (leave)\n", pm);
160
161 continue;
162 }
163 /* end if messages - check if anyone is waiting for sync */
164 if (up->up_dsleep) {
165 up->up_dsleep = 0;
166 cv_broadcast(&up->up_drain);
167 }
168 up->up_msleep = 1;
169 cv_wait(&up->up_cv, up->up_lock);
170 }
171
172 up->up_ptr = NULL;
173 cv_signal(&up->up_cv);
174 lockmgr(up->up_lock, LK_RELEASE);
175
176 /* Clear the proc pointer if this is the last thread. */
177 if (--usb_pcount == 0)
178 usbproc = NULL;
179
180 USB_THREAD_EXIT(0);
181 }
182
183 /*------------------------------------------------------------------------*
184 * usb_proc_create
185 *
186 * This function will create a process using the given "prio" that can
187 * execute callbacks. The mutex pointed to by "p_mtx" will be applied
188 * before calling the callbacks and released after that the callback
189 * has returned. The structure pointed to by "up" is assumed to be
190 * zeroed before this function is called.
191 *
192 * Return values:
193 * 0: success
194 * Else: failure
195 *------------------------------------------------------------------------*/
196 int
usb_proc_create(struct usb_process * up,struct lock * p_lock,const char * pmesg,uint8_t prio)197 usb_proc_create(struct usb_process *up, struct lock *p_lock,
198 const char *pmesg, uint8_t prio)
199 {
200 up->up_lock = p_lock;
201 up->up_prio = prio;
202
203 TAILQ_INIT(&up->up_qhead);
204
205 cv_init(&up->up_cv, "-");
206 cv_init(&up->up_drain, "usbdrain");
207
208 if (USB_THREAD_CREATE(&usb_process, up,
209 &up->up_ptr, "%s", pmesg)) {
210 DPRINTFN(0, "Unable to create USB process.");
211 up->up_ptr = NULL;
212 goto error;
213 }
214 usb_pcount++;
215 return (0);
216
217 error:
218 usb_proc_free(up);
219 return (ENOMEM);
220 }
221
222 /*------------------------------------------------------------------------*
223 * usb_proc_free
224 *
225 * NOTE: If the structure pointed to by "up" is all zero, this
226 * function does nothing.
227 *
228 * NOTE: Messages that are pending on the process queue will not be
229 * removed nor called.
230 *------------------------------------------------------------------------*/
231 void
usb_proc_free(struct usb_process * up)232 usb_proc_free(struct usb_process *up)
233 {
234 /* check if not initialised */
235 if (up->up_lock == NULL)
236 return;
237
238 usb_proc_drain(up);
239
240 cv_destroy(&up->up_cv);
241 cv_destroy(&up->up_drain);
242
243 /* make sure that we do not enter here again */
244 up->up_lock = NULL;
245 }
246
247 /*------------------------------------------------------------------------*
248 * usb_proc_msignal
249 *
250 * This function will queue one of the passed USB process messages on
251 * the USB process queue. The first message that is not already queued
252 * will get queued. If both messages are already queued the one queued
253 * last will be removed from the queue and queued in the end. The USB
254 * process mutex must be locked when calling this function. This
255 * function exploits the fact that a process can only do one callback
256 * at a time. The message that was queued is returned.
257 *------------------------------------------------------------------------*/
258 void *
usb_proc_msignal(struct usb_process * up,void * _pm0,void * _pm1)259 usb_proc_msignal(struct usb_process *up, void *_pm0, void *_pm1)
260 {
261 struct usb_proc_msg *pm0 = _pm0;
262 struct usb_proc_msg *pm1 = _pm1;
263 struct usb_proc_msg *pm2;
264 usb_size_t d;
265 uint8_t t;
266
267 /* check if gone, return dummy value */
268 if (up->up_gone)
269 return (_pm0);
270
271 KKASSERT(lockowned(up->up_lock));
272
273 t = 0;
274
275 if (pm0->pm_qentry.tqe_prev) {
276 t |= 1;
277 }
278 if (pm1->pm_qentry.tqe_prev) {
279 t |= 2;
280 }
281 if (t == 0) {
282 /*
283 * No entries are queued. Queue "pm0" and use the existing
284 * message number.
285 */
286 pm2 = pm0;
287 } else if (t == 1) {
288 /* Check if we need to increment the message number. */
289 if (pm0->pm_num == up->up_msg_num) {
290 up->up_msg_num++;
291 }
292 pm2 = pm1;
293 } else if (t == 2) {
294 /* Check if we need to increment the message number. */
295 if (pm1->pm_num == up->up_msg_num) {
296 up->up_msg_num++;
297 }
298 pm2 = pm0;
299 } else if (t == 3) {
300 /*
301 * Both entries are queued. Re-queue the entry closest to
302 * the end.
303 */
304 d = (pm1->pm_num - pm0->pm_num);
305
306 /* Check sign after subtraction */
307 if (d & 0x80000000) {
308 pm2 = pm0;
309 } else {
310 pm2 = pm1;
311 }
312
313 TAILQ_REMOVE(&up->up_qhead, pm2, pm_qentry);
314 } else {
315 pm2 = NULL; /* panic - should not happen */
316 }
317
318 DPRINTF(" t=%u, num=%u\n", t, up->up_msg_num);
319
320 /* Put message last on queue */
321
322 pm2->pm_num = up->up_msg_num;
323 TAILQ_INSERT_TAIL(&up->up_qhead, pm2, pm_qentry);
324
325 /* Check if we need to wakeup the USB process. */
326
327 if (up->up_msleep) {
328 up->up_msleep = 0; /* save "cv_signal()" calls */
329 cv_signal(&up->up_cv);
330 }
331 return (pm2);
332 }
333
334 /*------------------------------------------------------------------------*
335 * usb_proc_is_gone
336 *
337 * Return values:
338 * 0: USB process is running
339 * Else: USB process is tearing down
340 *------------------------------------------------------------------------*/
341 uint8_t
usb_proc_is_gone(struct usb_process * up)342 usb_proc_is_gone(struct usb_process *up)
343 {
344 if (up->up_gone)
345 return (1);
346
347 /*
348 * Allow calls when up_mtx is NULL, before the USB process
349 * structure is initialised.
350 */
351 if (up->up_lock != NULL)
352 KKASSERT(lockowned(up->up_lock));
353 return (0);
354 }
355
356 /*------------------------------------------------------------------------*
357 * usb_proc_mwait
358 *
359 * This function will return when the USB process message pointed to
360 * by "pm" is no longer on a queue. This function must be called
361 * having "up->up_mtx" locked.
362 *------------------------------------------------------------------------*/
363 void
usb_proc_mwait(struct usb_process * up,void * _pm0,void * _pm1)364 usb_proc_mwait(struct usb_process *up, void *_pm0, void *_pm1)
365 {
366 struct usb_proc_msg *pm0 = _pm0;
367 struct usb_proc_msg *pm1 = _pm1;
368
369 /* check if gone */
370 if (up->up_gone)
371 return;
372
373 KKASSERT(lockowned(up->up_lock));
374
375 if (up->up_curtd == curthread) {
376 /* Just remove the messages from the queue. */
377 if (pm0->pm_qentry.tqe_prev) {
378 TAILQ_REMOVE(&up->up_qhead, pm0, pm_qentry);
379 pm0->pm_qentry.tqe_prev = NULL;
380 }
381 if (pm1->pm_qentry.tqe_prev) {
382 TAILQ_REMOVE(&up->up_qhead, pm1, pm_qentry);
383 pm1->pm_qentry.tqe_prev = NULL;
384 }
385 } else
386 while (pm0->pm_qentry.tqe_prev ||
387 pm1->pm_qentry.tqe_prev) {
388 /* check if config thread is gone */
389 if (up->up_gone)
390 break;
391 up->up_dsleep = 1;
392 cv_wait(&up->up_drain, up->up_lock);
393 }
394 }
395
396 /*------------------------------------------------------------------------*
397 * usb_proc_drain
398 *
399 * This function will tear down an USB process, waiting for the
400 * currently executing command to return.
401 *
402 * NOTE: If the structure pointed to by "up" is all zero,
403 * this function does nothing.
404 *------------------------------------------------------------------------*/
405 void
usb_proc_drain(struct usb_process * up)406 usb_proc_drain(struct usb_process *up)
407 {
408 /* check if not initialised */
409 if (up->up_lock == NULL)
410 return;
411 #if 0 /* XXX */
412 /* handle special case with Giant */
413 if (up->up_mtx != &Giant)
414 mtx_assert(up->up_mtx, MA_NOTOWNED);
415 #else
416 KKASSERT(!lockowned(up->up_lock));
417 lockmgr(up->up_lock, LK_EXCLUSIVE);
418 #endif
419
420 /* Set the gone flag */
421
422 up->up_gone = 1;
423
424 while (up->up_ptr) {
425
426 /* Check if we need to wakeup the USB process */
427
428 if (up->up_msleep || up->up_csleep) {
429 up->up_msleep = 0;
430 up->up_csleep = 0;
431 cv_signal(&up->up_cv);
432 }
433 /* Check if we are still cold booted */
434
435 if (cold) {
436 USB_THREAD_SUSPEND(up->up_ptr);
437 kprintf("WARNING: A USB process has "
438 "been left suspended\n");
439 break;
440 }
441 cv_wait(&up->up_cv, up->up_lock);
442 }
443 /* Check if someone is waiting - should not happen */
444
445 if (up->up_dsleep) {
446 up->up_dsleep = 0;
447 cv_broadcast(&up->up_drain);
448 DPRINTF("WARNING: Someone is waiting "
449 "for USB process drain!\n");
450 }
451 lockmgr(up->up_lock, LK_RELEASE);
452 }
453
454 /*------------------------------------------------------------------------*
455 * usb_proc_rewakeup
456 *
457 * This function is called to re-wakeup the given USB
458 * process. This usually happens after that the USB system has been in
459 * polling mode, like during a panic. This function must be called
460 * having "up->up_lock" locked.
461 *------------------------------------------------------------------------*/
462 void
usb_proc_rewakeup(struct usb_process * up)463 usb_proc_rewakeup(struct usb_process *up)
464 {
465 /* check if not initialised */
466 if (up->up_lock == NULL)
467 return;
468 /* check if gone */
469 if (up->up_gone)
470 return;
471
472 KKASSERT(lockowned(up->up_lock));
473
474 if (up->up_msleep == 0) {
475 /* re-wakeup */
476 cv_signal(&up->up_cv);
477 }
478 }
479
480 /*------------------------------------------------------------------------*
481 * usb_proc_is_called_from
482 *
483 * This function will return non-zero if called from inside the USB
484 * process passed as first argument. Else this function returns zero.
485 *------------------------------------------------------------------------*/
486 int
usb_proc_is_called_from(struct usb_process * up)487 usb_proc_is_called_from(struct usb_process *up)
488 {
489 return (up->up_curtd == curthread);
490 }
491