1 /* $FreeBSD$ */ 2 /*- 3 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 4 * 5 * Copyright (c) 2008 Hans Petter Selasky. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #ifdef USB_GLOBAL_INCLUDE_FILE 30 #include USB_GLOBAL_INCLUDE_FILE 31 #else 32 #include <sys/stdint.h> 33 #include <sys/stddef.h> 34 #include <sys/param.h> 35 #include <sys/queue.h> 36 #include <sys/types.h> 37 #include <sys/systm.h> 38 #include <sys/kernel.h> 39 #include <sys/bus.h> 40 #include <sys/module.h> 41 #include <sys/lock.h> 42 #include <sys/mutex.h> 43 #include <sys/condvar.h> 44 #include <sys/sysctl.h> 45 #include <sys/sx.h> 46 #include <sys/unistd.h> 47 #include <sys/callout.h> 48 #include <sys/malloc.h> 49 #include <sys/priv.h> 50 51 #include <dev/usb/usb.h> 52 #include <dev/usb/usbdi.h> 53 #include <dev/usb/usbdi_util.h> 54 #include <dev/usb/usb_process.h> 55 56 #define USB_DEBUG_VAR usb_proc_debug 57 #include <dev/usb/usb_debug.h> 58 #include <dev/usb/usb_util.h> 59 60 #include <sys/proc.h> 61 #include <sys/kthread.h> 62 #include <sys/sched.h> 63 #endif /* USB_GLOBAL_INCLUDE_FILE */ 64 65 #if (__FreeBSD_version < 700000) 66 #define thread_lock(td) mtx_lock_spin(&sched_lock) 67 #define thread_unlock(td) mtx_unlock_spin(&sched_lock) 68 #endif 69 70 #if (__FreeBSD_version >= 800000) 71 static struct proc *usbproc; 72 static int usb_pcount; 73 #define USB_THREAD_CREATE(f, s, p, ...) \ 74 kproc_kthread_add((f), (s), &usbproc, (p), RFHIGHPID, \ 75 0, "usb", __VA_ARGS__) 76 #if (__FreeBSD_version >= 900000) 77 #define USB_THREAD_SUSPEND_CHECK() kthread_suspend_check() 78 #else 79 #define USB_THREAD_SUSPEND_CHECK() kthread_suspend_check(curthread) 80 #endif 81 #define USB_THREAD_SUSPEND(p) kthread_suspend(p,0) 82 #define USB_THREAD_EXIT(err) kthread_exit() 83 #else 84 #define USB_THREAD_CREATE(f, s, p, ...) \ 85 kthread_create((f), (s), (p), RFHIGHPID, 0, __VA_ARGS__) 86 #define USB_THREAD_SUSPEND_CHECK() kthread_suspend_check(curproc) 87 #define USB_THREAD_SUSPEND(p) kthread_suspend(p,0) 88 #define USB_THREAD_EXIT(err) kthread_exit(err) 89 #endif 90 91 #ifdef USB_DEBUG 92 static int usb_proc_debug; 93 94 static SYSCTL_NODE(_hw_usb, OID_AUTO, proc, CTLFLAG_RW, 0, "USB process"); 95 SYSCTL_INT(_hw_usb_proc, OID_AUTO, debug, CTLFLAG_RWTUN, &usb_proc_debug, 0, 96 "Debug level"); 97 #endif 98 99 /*------------------------------------------------------------------------* 100 * usb_process 101 * 102 * This function is the USB process dispatcher. 103 *------------------------------------------------------------------------*/ 104 static void 105 usb_process(void *arg) 106 { 107 struct usb_process *up = arg; 108 struct usb_proc_msg *pm; 109 struct thread *td; 110 111 /* in case of attach error, check for suspended */ 112 USB_THREAD_SUSPEND_CHECK(); 113 114 /* adjust priority */ 115 td = curthread; 116 thread_lock(td); 117 sched_prio(td, up->up_prio); 118 thread_unlock(td); 119 120 USB_MTX_LOCK(up->up_mtx); 121 122 up->up_curtd = td; 123 124 while (1) { 125 126 if (up->up_gone) 127 break; 128 129 /* 130 * NOTE to reimplementors: dequeueing a command from the 131 * "used" queue and executing it must be atomic, with regard 132 * to the "up_mtx" mutex. That means any attempt to queue a 133 * command by another thread must be blocked until either: 134 * 135 * 1) the command sleeps 136 * 137 * 2) the command returns 138 * 139 * Here is a practical example that shows how this helps 140 * solving a problem: 141 * 142 * Assume that you want to set the baud rate on a USB serial 143 * device. During the programming of the device you don't 144 * want to receive nor transmit any data, because it will be 145 * garbage most likely anyway. The programming of our USB 146 * device takes 20 milliseconds and it needs to call 147 * functions that sleep. 148 * 149 * Non-working solution: Before we queue the programming 150 * command, we stop transmission and reception of data. Then 151 * we queue a programming command. At the end of the 152 * programming command we enable transmission and reception 153 * of data. 154 * 155 * Problem: If a second programming command is queued while the 156 * first one is sleeping, we end up enabling transmission 157 * and reception of data too early. 158 * 159 * Working solution: Before we queue the programming command, 160 * we stop transmission and reception of data. Then we queue 161 * a programming command. Then we queue a second command 162 * that only enables transmission and reception of data. 163 * 164 * Why it works: If a second programming command is queued 165 * while the first one is sleeping, then the queueing of a 166 * second command to enable the data transfers, will cause 167 * the previous one, which is still on the queue, to be 168 * removed from the queue, and re-inserted after the last 169 * baud rate programming command, which then gives the 170 * desired result. 171 */ 172 pm = TAILQ_FIRST(&up->up_qhead); 173 174 if (pm) { 175 DPRINTF("Message pm=%p, cb=%p (enter)\n", 176 pm, pm->pm_callback); 177 178 (pm->pm_callback) (pm); 179 180 if (pm == TAILQ_FIRST(&up->up_qhead)) { 181 /* nothing changed */ 182 TAILQ_REMOVE(&up->up_qhead, pm, pm_qentry); 183 pm->pm_qentry.tqe_prev = NULL; 184 } 185 DPRINTF("Message pm=%p (leave)\n", pm); 186 187 continue; 188 } 189 /* end of messages - check if anyone is waiting for sync */ 190 if (up->up_dsleep) { 191 up->up_dsleep = 0; 192 cv_broadcast(&up->up_drain); 193 } 194 up->up_msleep = 1; 195 cv_wait(&up->up_cv, up->up_mtx); 196 } 197 198 up->up_ptr = NULL; 199 cv_signal(&up->up_cv); 200 USB_MTX_UNLOCK(up->up_mtx); 201 #if (__FreeBSD_version >= 800000) 202 /* Clear the proc pointer if this is the last thread. */ 203 if (--usb_pcount == 0) 204 usbproc = NULL; 205 #endif 206 207 USB_THREAD_EXIT(0); 208 } 209 210 /*------------------------------------------------------------------------* 211 * usb_proc_create 212 * 213 * This function will create a process using the given "prio" that can 214 * execute callbacks. The mutex pointed to by "p_mtx" will be applied 215 * before calling the callbacks and released after that the callback 216 * has returned. The structure pointed to by "up" is assumed to be 217 * zeroed before this function is called. 218 * 219 * Return values: 220 * 0: success 221 * Else: failure 222 *------------------------------------------------------------------------*/ 223 int 224 usb_proc_create(struct usb_process *up, struct mtx *p_mtx, 225 const char *pmesg, uint8_t prio) 226 { 227 up->up_mtx = p_mtx; 228 up->up_prio = prio; 229 230 TAILQ_INIT(&up->up_qhead); 231 232 cv_init(&up->up_cv, "-"); 233 cv_init(&up->up_drain, "usbdrain"); 234 235 if (USB_THREAD_CREATE(&usb_process, up, 236 &up->up_ptr, "%s", pmesg)) { 237 DPRINTFN(0, "Unable to create USB process."); 238 up->up_ptr = NULL; 239 goto error; 240 } 241 #if (__FreeBSD_version >= 800000) 242 usb_pcount++; 243 #endif 244 return (0); 245 246 error: 247 usb_proc_free(up); 248 return (ENOMEM); 249 } 250 251 /*------------------------------------------------------------------------* 252 * usb_proc_free 253 * 254 * NOTE: If the structure pointed to by "up" is all zero, this 255 * function does nothing. 256 * 257 * NOTE: Messages that are pending on the process queue will not be 258 * removed nor called. 259 *------------------------------------------------------------------------*/ 260 void 261 usb_proc_free(struct usb_process *up) 262 { 263 /* check if not initialised */ 264 if (up->up_mtx == NULL) 265 return; 266 267 usb_proc_drain(up); 268 269 cv_destroy(&up->up_cv); 270 cv_destroy(&up->up_drain); 271 272 /* make sure that we do not enter here again */ 273 up->up_mtx = NULL; 274 } 275 276 /*------------------------------------------------------------------------* 277 * usb_proc_msignal 278 * 279 * This function will queue one of the passed USB process messages on 280 * the USB process queue. The first message that is not already queued 281 * will get queued. If both messages are already queued the one queued 282 * last will be removed from the queue and queued in the end. The USB 283 * process mutex must be locked when calling this function. This 284 * function exploits the fact that a process can only do one callback 285 * at a time. The message that was queued is returned. 286 *------------------------------------------------------------------------*/ 287 void * 288 usb_proc_msignal(struct usb_process *up, void *_pm0, void *_pm1) 289 { 290 struct usb_proc_msg *pm0 = _pm0; 291 struct usb_proc_msg *pm1 = _pm1; 292 struct usb_proc_msg *pm2; 293 usb_size_t d; 294 uint8_t t; 295 296 /* check if gone or in polling mode, return dummy value */ 297 if (up->up_gone != 0 || 298 USB_IN_POLLING_MODE_FUNC() != 0) 299 return (_pm0); 300 301 USB_MTX_ASSERT(up->up_mtx, MA_OWNED); 302 303 t = 0; 304 305 if (pm0->pm_qentry.tqe_prev) { 306 t |= 1; 307 } 308 if (pm1->pm_qentry.tqe_prev) { 309 t |= 2; 310 } 311 if (t == 0) { 312 /* 313 * No entries are queued. Queue "pm0" and use the existing 314 * message number. 315 */ 316 pm2 = pm0; 317 } else if (t == 1) { 318 /* Check if we need to increment the message number. */ 319 if (pm0->pm_num == up->up_msg_num) { 320 up->up_msg_num++; 321 } 322 pm2 = pm1; 323 } else if (t == 2) { 324 /* Check if we need to increment the message number. */ 325 if (pm1->pm_num == up->up_msg_num) { 326 up->up_msg_num++; 327 } 328 pm2 = pm0; 329 } else if (t == 3) { 330 /* 331 * Both entries are queued. Re-queue the entry closest to 332 * the end. 333 */ 334 d = (pm1->pm_num - pm0->pm_num); 335 336 /* Check sign after subtraction */ 337 if (d & 0x80000000) { 338 pm2 = pm0; 339 } else { 340 pm2 = pm1; 341 } 342 343 TAILQ_REMOVE(&up->up_qhead, pm2, pm_qentry); 344 } else { 345 pm2 = NULL; /* panic - should not happen */ 346 } 347 348 DPRINTF(" t=%u, num=%u\n", t, up->up_msg_num); 349 350 /* Put message last on queue */ 351 352 pm2->pm_num = up->up_msg_num; 353 TAILQ_INSERT_TAIL(&up->up_qhead, pm2, pm_qentry); 354 355 /* Check if we need to wakeup the USB process. */ 356 357 if (up->up_msleep) { 358 up->up_msleep = 0; /* save "cv_signal()" calls */ 359 cv_signal(&up->up_cv); 360 } 361 return (pm2); 362 } 363 364 /*------------------------------------------------------------------------* 365 * usb_proc_is_gone 366 * 367 * Return values: 368 * 0: USB process is running 369 * Else: USB process is tearing down 370 *------------------------------------------------------------------------*/ 371 uint8_t 372 usb_proc_is_gone(struct usb_process *up) 373 { 374 if (up->up_gone) 375 return (1); 376 377 /* 378 * Allow calls when up_mtx is NULL, before the USB process 379 * structure is initialised. 380 */ 381 if (up->up_mtx != NULL) 382 USB_MTX_ASSERT(up->up_mtx, MA_OWNED); 383 return (0); 384 } 385 386 /*------------------------------------------------------------------------* 387 * usb_proc_mwait 388 * 389 * This function will return when the USB process message pointed to 390 * by "pm" is no longer on a queue. This function must be called 391 * having "up->up_mtx" locked. 392 *------------------------------------------------------------------------*/ 393 void 394 usb_proc_mwait(struct usb_process *up, void *_pm0, void *_pm1) 395 { 396 struct usb_proc_msg *pm0 = _pm0; 397 struct usb_proc_msg *pm1 = _pm1; 398 399 /* check if gone */ 400 if (up->up_gone) 401 return; 402 403 USB_MTX_ASSERT(up->up_mtx, MA_OWNED); 404 405 if (up->up_curtd == curthread) { 406 /* Just remove the messages from the queue. */ 407 if (pm0->pm_qentry.tqe_prev) { 408 TAILQ_REMOVE(&up->up_qhead, pm0, pm_qentry); 409 pm0->pm_qentry.tqe_prev = NULL; 410 } 411 if (pm1->pm_qentry.tqe_prev) { 412 TAILQ_REMOVE(&up->up_qhead, pm1, pm_qentry); 413 pm1->pm_qentry.tqe_prev = NULL; 414 } 415 } else 416 while (pm0->pm_qentry.tqe_prev || 417 pm1->pm_qentry.tqe_prev) { 418 /* check if config thread is gone */ 419 if (up->up_gone) 420 break; 421 up->up_dsleep = 1; 422 cv_wait(&up->up_drain, up->up_mtx); 423 } 424 } 425 426 /*------------------------------------------------------------------------* 427 * usb_proc_drain 428 * 429 * This function will tear down an USB process, waiting for the 430 * currently executing command to return. 431 * 432 * NOTE: If the structure pointed to by "up" is all zero, 433 * this function does nothing. 434 *------------------------------------------------------------------------*/ 435 void 436 usb_proc_drain(struct usb_process *up) 437 { 438 /* check if not initialised */ 439 if (up->up_mtx == NULL) 440 return; 441 /* handle special case with Giant */ 442 if (up->up_mtx != &Giant) 443 USB_MTX_ASSERT(up->up_mtx, MA_NOTOWNED); 444 445 USB_MTX_LOCK(up->up_mtx); 446 447 /* Set the gone flag */ 448 449 up->up_gone = 1; 450 451 while (up->up_ptr) { 452 453 /* Check if we need to wakeup the USB process */ 454 455 if (up->up_msleep || up->up_csleep) { 456 up->up_msleep = 0; 457 up->up_csleep = 0; 458 cv_signal(&up->up_cv); 459 } 460 #ifndef EARLY_AP_STARTUP 461 /* Check if we are still cold booted */ 462 if (cold) { 463 USB_THREAD_SUSPEND(up->up_ptr); 464 printf("WARNING: A USB process has " 465 "been left suspended\n"); 466 break; 467 } 468 #endif 469 cv_wait(&up->up_cv, up->up_mtx); 470 } 471 /* Check if someone is waiting - should not happen */ 472 473 if (up->up_dsleep) { 474 up->up_dsleep = 0; 475 cv_broadcast(&up->up_drain); 476 DPRINTF("WARNING: Someone is waiting " 477 "for USB process drain!\n"); 478 } 479 USB_MTX_UNLOCK(up->up_mtx); 480 } 481 482 /*------------------------------------------------------------------------* 483 * usb_proc_rewakeup 484 * 485 * This function is called to re-wakeup the given USB 486 * process. This usually happens after that the USB system has been in 487 * polling mode, like during a panic. This function must be called 488 * having "up->up_mtx" locked. 489 *------------------------------------------------------------------------*/ 490 void 491 usb_proc_rewakeup(struct usb_process *up) 492 { 493 /* check if not initialised */ 494 if (up->up_mtx == NULL) 495 return; 496 /* check if gone */ 497 if (up->up_gone) 498 return; 499 500 USB_MTX_ASSERT(up->up_mtx, MA_OWNED); 501 502 if (up->up_msleep == 0) { 503 /* re-wakeup */ 504 cv_signal(&up->up_cv); 505 } 506 } 507 508 /*------------------------------------------------------------------------* 509 * usb_proc_is_called_from 510 * 511 * This function will return non-zero if called from inside the USB 512 * process passed as first argument. Else this function returns zero. 513 *------------------------------------------------------------------------*/ 514 int 515 usb_proc_is_called_from(struct usb_process *up) 516 { 517 return (up->up_curtd == curthread); 518 } 519