1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2008 Hans Petter Selasky. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #ifdef USB_GLOBAL_INCLUDE_FILE
29 #include USB_GLOBAL_INCLUDE_FILE
30 #else
31 #include <sys/stdint.h>
32 #include <sys/stddef.h>
33 #include <sys/param.h>
34 #include <sys/queue.h>
35 #include <sys/types.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/bus.h>
39 #include <sys/module.h>
40 #include <sys/lock.h>
41 #include <sys/mutex.h>
42 #include <sys/condvar.h>
43 #include <sys/sysctl.h>
44 #include <sys/sx.h>
45 #include <sys/unistd.h>
46 #include <sys/callout.h>
47 #include <sys/malloc.h>
48 #include <sys/priv.h>
49
50 #include <dev/usb/usb.h>
51 #include <dev/usb/usbdi.h>
52 #include <dev/usb/usbdi_util.h>
53 #include <dev/usb/usb_process.h>
54
55 #define USB_DEBUG_VAR usb_proc_debug
56 #include <dev/usb/usb_debug.h>
57 #include <dev/usb/usb_util.h>
58
59 #include <sys/proc.h>
60 #include <sys/kthread.h>
61 #include <sys/sched.h>
62 #endif /* USB_GLOBAL_INCLUDE_FILE */
63
64 static struct proc *usbproc;
65 static int usb_pcount;
66 #define USB_THREAD_CREATE(f, s, p, ...) \
67 kproc_kthread_add((f), (s), &usbproc, (p), RFHIGHPID, \
68 0, "usb", __VA_ARGS__)
69 #define USB_THREAD_SUSPEND_CHECK() kthread_suspend_check()
70 #define USB_THREAD_SUSPEND(p) kthread_suspend(p,0)
71 #define USB_THREAD_EXIT(err) kthread_exit()
72
73 #ifdef USB_DEBUG
74 static int usb_proc_debug;
75
76 static SYSCTL_NODE(_hw_usb, OID_AUTO, proc, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
77 "USB process");
78 SYSCTL_INT(_hw_usb_proc, OID_AUTO, debug, CTLFLAG_RWTUN, &usb_proc_debug, 0,
79 "Debug level");
80 #endif
81
82 /*------------------------------------------------------------------------*
83 * usb_process
84 *
85 * This function is the USB process dispatcher.
86 *------------------------------------------------------------------------*/
87 static void
usb_process(void * arg)88 usb_process(void *arg)
89 {
90 struct usb_process *up = arg;
91 struct usb_proc_msg *pm;
92 struct thread *td;
93
94 /* in case of attach error, check for suspended */
95 USB_THREAD_SUSPEND_CHECK();
96
97 /* adjust priority */
98 td = curthread;
99 thread_lock(td);
100 sched_prio(td, up->up_prio);
101 thread_unlock(td);
102
103 USB_MTX_LOCK(up->up_mtx);
104
105 up->up_curtd = td;
106
107 while (1) {
108 if (up->up_gone)
109 break;
110
111 /*
112 * NOTE to reimplementors: dequeueing a command from the
113 * "used" queue and executing it must be atomic, with regard
114 * to the "up_mtx" mutex. That means any attempt to queue a
115 * command by another thread must be blocked until either:
116 *
117 * 1) the command sleeps
118 *
119 * 2) the command returns
120 *
121 * Here is a practical example that shows how this helps
122 * solving a problem:
123 *
124 * Assume that you want to set the baud rate on a USB serial
125 * device. During the programming of the device you don't
126 * want to receive nor transmit any data, because it will be
127 * garbage most likely anyway. The programming of our USB
128 * device takes 20 milliseconds and it needs to call
129 * functions that sleep.
130 *
131 * Non-working solution: Before we queue the programming
132 * command, we stop transmission and reception of data. Then
133 * we queue a programming command. At the end of the
134 * programming command we enable transmission and reception
135 * of data.
136 *
137 * Problem: If a second programming command is queued while the
138 * first one is sleeping, we end up enabling transmission
139 * and reception of data too early.
140 *
141 * Working solution: Before we queue the programming command,
142 * we stop transmission and reception of data. Then we queue
143 * a programming command. Then we queue a second command
144 * that only enables transmission and reception of data.
145 *
146 * Why it works: If a second programming command is queued
147 * while the first one is sleeping, then the queueing of a
148 * second command to enable the data transfers, will cause
149 * the previous one, which is still on the queue, to be
150 * removed from the queue, and re-inserted after the last
151 * baud rate programming command, which then gives the
152 * desired result.
153 */
154 pm = TAILQ_FIRST(&up->up_qhead);
155
156 if (pm) {
157 DPRINTF("Message pm=%p, cb=%p (enter)\n",
158 pm, pm->pm_callback);
159
160 (pm->pm_callback) (pm);
161
162 if (pm == TAILQ_FIRST(&up->up_qhead)) {
163 /* nothing changed */
164 TAILQ_REMOVE(&up->up_qhead, pm, pm_qentry);
165 pm->pm_qentry.tqe_prev = NULL;
166 }
167 DPRINTF("Message pm=%p (leave)\n", pm);
168
169 continue;
170 }
171 /* end of messages - check if anyone is waiting for sync */
172 if (up->up_dsleep) {
173 up->up_dsleep = 0;
174 cv_broadcast(&up->up_drain);
175 }
176 up->up_msleep = 1;
177 cv_wait(&up->up_cv, up->up_mtx);
178 }
179
180 up->up_ptr = NULL;
181 cv_signal(&up->up_cv);
182 USB_MTX_UNLOCK(up->up_mtx);
183 /* Clear the proc pointer if this is the last thread. */
184 if (--usb_pcount == 0)
185 usbproc = NULL;
186
187 USB_THREAD_EXIT(0);
188 }
189
190 /*------------------------------------------------------------------------*
191 * usb_proc_create
192 *
193 * This function will create a process using the given "prio" that can
194 * execute callbacks. The mutex pointed to by "p_mtx" will be applied
195 * before calling the callbacks and released after that the callback
196 * has returned. The structure pointed to by "up" is assumed to be
197 * zeroed before this function is called.
198 *
199 * Return values:
200 * 0: success
201 * Else: failure
202 *------------------------------------------------------------------------*/
203 int
usb_proc_create(struct usb_process * up,struct mtx * p_mtx,const char * pmesg,uint8_t prio)204 usb_proc_create(struct usb_process *up, struct mtx *p_mtx,
205 const char *pmesg, uint8_t prio)
206 {
207 up->up_mtx = p_mtx;
208 up->up_prio = prio;
209
210 TAILQ_INIT(&up->up_qhead);
211
212 cv_init(&up->up_cv, "-");
213 cv_init(&up->up_drain, "usbdrain");
214
215 if (USB_THREAD_CREATE(&usb_process, up,
216 &up->up_ptr, "%s", pmesg)) {
217 DPRINTFN(0, "Unable to create USB process.");
218 up->up_ptr = NULL;
219 goto error;
220 }
221 usb_pcount++;
222 return (0);
223
224 error:
225 usb_proc_free(up);
226 return (ENOMEM);
227 }
228
229 /*------------------------------------------------------------------------*
230 * usb_proc_free
231 *
232 * NOTE: If the structure pointed to by "up" is all zero, this
233 * function does nothing.
234 *
235 * NOTE: Messages that are pending on the process queue will not be
236 * removed nor called.
237 *------------------------------------------------------------------------*/
238 void
usb_proc_free(struct usb_process * up)239 usb_proc_free(struct usb_process *up)
240 {
241 /* check if not initialised */
242 if (up->up_mtx == NULL)
243 return;
244
245 usb_proc_drain(up);
246
247 cv_destroy(&up->up_cv);
248 cv_destroy(&up->up_drain);
249
250 /* make sure that we do not enter here again */
251 up->up_mtx = NULL;
252 }
253
254 /*------------------------------------------------------------------------*
255 * usb_proc_msignal
256 *
257 * This function will queue one of the passed USB process messages on
258 * the USB process queue. The first message that is not already queued
259 * will get queued. If both messages are already queued the one queued
260 * last will be removed from the queue and queued in the end. The USB
261 * process mutex must be locked when calling this function. This
262 * function exploits the fact that a process can only do one callback
263 * at a time. The message that was queued is returned.
264 *------------------------------------------------------------------------*/
265 void *
usb_proc_msignal(struct usb_process * up,void * _pm0,void * _pm1)266 usb_proc_msignal(struct usb_process *up, void *_pm0, void *_pm1)
267 {
268 struct usb_proc_msg *pm0 = _pm0;
269 struct usb_proc_msg *pm1 = _pm1;
270 struct usb_proc_msg *pm2;
271 usb_size_t d;
272 uint8_t t;
273
274 /* check if gone or in polling mode, return dummy value */
275 if (up->up_gone != 0 ||
276 USB_IN_POLLING_MODE_FUNC() != 0)
277 return (_pm0);
278
279 USB_MTX_ASSERT(up->up_mtx, MA_OWNED);
280
281 t = 0;
282
283 if (pm0->pm_qentry.tqe_prev) {
284 t |= 1;
285 }
286 if (pm1->pm_qentry.tqe_prev) {
287 t |= 2;
288 }
289 if (t == 0) {
290 /*
291 * No entries are queued. Queue "pm0" and use the existing
292 * message number.
293 */
294 pm2 = pm0;
295 } else if (t == 1) {
296 /* Check if we need to increment the message number. */
297 if (pm0->pm_num == up->up_msg_num) {
298 up->up_msg_num++;
299 }
300 pm2 = pm1;
301 } else if (t == 2) {
302 /* Check if we need to increment the message number. */
303 if (pm1->pm_num == up->up_msg_num) {
304 up->up_msg_num++;
305 }
306 pm2 = pm0;
307 } else if (t == 3) {
308 /*
309 * Both entries are queued. Re-queue the entry closest to
310 * the end.
311 */
312 d = (pm1->pm_num - pm0->pm_num);
313
314 /* Check sign after subtraction */
315 if (d & 0x80000000) {
316 pm2 = pm0;
317 } else {
318 pm2 = pm1;
319 }
320
321 TAILQ_REMOVE(&up->up_qhead, pm2, pm_qentry);
322 } else {
323 pm2 = NULL; /* panic - should not happen */
324 }
325
326 DPRINTF(" t=%u, num=%u\n", t, up->up_msg_num);
327
328 /* Put message last on queue */
329
330 pm2->pm_num = up->up_msg_num;
331 TAILQ_INSERT_TAIL(&up->up_qhead, pm2, pm_qentry);
332
333 /* Check if we need to wakeup the USB process. */
334
335 if (up->up_msleep) {
336 up->up_msleep = 0; /* save "cv_signal()" calls */
337 cv_signal(&up->up_cv);
338 }
339 return (pm2);
340 }
341
342 /*------------------------------------------------------------------------*
343 * usb_proc_is_gone
344 *
345 * Return values:
346 * 0: USB process is running
347 * Else: USB process is tearing down
348 *------------------------------------------------------------------------*/
349 uint8_t
usb_proc_is_gone(struct usb_process * up)350 usb_proc_is_gone(struct usb_process *up)
351 {
352 if (up->up_gone)
353 return (1);
354
355 /*
356 * Allow calls when up_mtx is NULL, before the USB process
357 * structure is initialised.
358 */
359 if (up->up_mtx != NULL)
360 USB_MTX_ASSERT(up->up_mtx, MA_OWNED);
361 return (0);
362 }
363
364 /*------------------------------------------------------------------------*
365 * usb_proc_mwait
366 *
367 * This function will return when the USB process message pointed to
368 * by "pm" is no longer on a queue. This function must be called
369 * having "up->up_mtx" locked.
370 *------------------------------------------------------------------------*/
371 void
usb_proc_mwait(struct usb_process * up,void * _pm0,void * _pm1)372 usb_proc_mwait(struct usb_process *up, void *_pm0, void *_pm1)
373 {
374 struct usb_proc_msg *pm0 = _pm0;
375 struct usb_proc_msg *pm1 = _pm1;
376
377 /* check if gone */
378 if (up->up_gone)
379 return;
380
381 USB_MTX_ASSERT(up->up_mtx, MA_OWNED);
382
383 if (up->up_curtd == curthread) {
384 /* Just remove the messages from the queue. */
385 if (pm0->pm_qentry.tqe_prev) {
386 TAILQ_REMOVE(&up->up_qhead, pm0, pm_qentry);
387 pm0->pm_qentry.tqe_prev = NULL;
388 }
389 if (pm1->pm_qentry.tqe_prev) {
390 TAILQ_REMOVE(&up->up_qhead, pm1, pm_qentry);
391 pm1->pm_qentry.tqe_prev = NULL;
392 }
393 } else
394 while (pm0->pm_qentry.tqe_prev ||
395 pm1->pm_qentry.tqe_prev) {
396 /* check if config thread is gone */
397 if (up->up_gone)
398 break;
399 up->up_dsleep = 1;
400 cv_wait(&up->up_drain, up->up_mtx);
401 }
402 }
403
404 /*------------------------------------------------------------------------*
405 * usb_proc_drain
406 *
407 * This function will tear down an USB process, waiting for the
408 * currently executing command to return.
409 *
410 * NOTE: If the structure pointed to by "up" is all zero,
411 * this function does nothing.
412 *------------------------------------------------------------------------*/
413 void
usb_proc_drain(struct usb_process * up)414 usb_proc_drain(struct usb_process *up)
415 {
416 /* check if not initialised */
417 if (up->up_mtx == NULL)
418 return;
419 /* handle special case with Giant */
420 if (up->up_mtx != &Giant)
421 USB_MTX_ASSERT(up->up_mtx, MA_NOTOWNED);
422
423 USB_MTX_LOCK(up->up_mtx);
424
425 /* Set the gone flag */
426
427 up->up_gone = 1;
428
429 while (up->up_ptr) {
430 /* Check if we need to wakeup the USB process */
431
432 if (up->up_msleep || up->up_csleep) {
433 up->up_msleep = 0;
434 up->up_csleep = 0;
435 cv_signal(&up->up_cv);
436 }
437 #ifndef EARLY_AP_STARTUP
438 /* Check if we are still cold booted */
439 if (cold) {
440 USB_THREAD_SUSPEND(up->up_ptr);
441 printf("WARNING: A USB process has "
442 "been left suspended\n");
443 break;
444 }
445 #endif
446 cv_wait(&up->up_cv, up->up_mtx);
447 }
448 /* Check if someone is waiting - should not happen */
449
450 if (up->up_dsleep) {
451 up->up_dsleep = 0;
452 cv_broadcast(&up->up_drain);
453 DPRINTF("WARNING: Someone is waiting "
454 "for USB process drain!\n");
455 }
456 USB_MTX_UNLOCK(up->up_mtx);
457 }
458
459 /*------------------------------------------------------------------------*
460 * usb_proc_rewakeup
461 *
462 * This function is called to re-wakeup the given USB
463 * process. This usually happens after that the USB system has been in
464 * polling mode, like during a panic. This function must be called
465 * having "up->up_mtx" locked.
466 *------------------------------------------------------------------------*/
467 void
usb_proc_rewakeup(struct usb_process * up)468 usb_proc_rewakeup(struct usb_process *up)
469 {
470 /* check if not initialised */
471 if (up->up_mtx == NULL)
472 return;
473 /* check if gone */
474 if (up->up_gone)
475 return;
476
477 USB_MTX_ASSERT(up->up_mtx, MA_OWNED);
478
479 if (up->up_msleep == 0) {
480 /* re-wakeup */
481 cv_signal(&up->up_cv);
482 }
483 }
484
485 /*------------------------------------------------------------------------*
486 * usb_proc_is_called_from
487 *
488 * This function will return non-zero if called from inside the USB
489 * process passed as first argument. Else this function returns zero.
490 *------------------------------------------------------------------------*/
491 int
usb_proc_is_called_from(struct usb_process * up)492 usb_proc_is_called_from(struct usb_process *up)
493 {
494 return (up->up_curtd == curthread);
495 }
496