1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * PTP 1588 clock support - character device implementation. 4 * 5 * Copyright (C) 2010 OMICRON electronics GmbH 6 */ 7 #include <linux/compat.h> 8 #include <linux/module.h> 9 #include <linux/posix-clock.h> 10 #include <linux/poll.h> 11 #include <linux/sched.h> 12 #include <linux/slab.h> 13 #include <linux/timekeeping.h> 14 #include <linux/debugfs.h> 15 16 #include <linux/nospec.h> 17 18 #include "ptp_private.h" 19 20 static int ptp_disable_pinfunc(struct ptp_clock_info *ops, 21 enum ptp_pin_function func, unsigned int chan) 22 { 23 struct ptp_clock_request rq; 24 int err = 0; 25 26 memset(&rq, 0, sizeof(rq)); 27 28 switch (func) { 29 case PTP_PF_NONE: 30 break; 31 case PTP_PF_EXTTS: 32 rq.type = PTP_CLK_REQ_EXTTS; 33 rq.extts.index = chan; 34 err = ops->enable(ops, &rq, 0); 35 break; 36 case PTP_PF_PEROUT: 37 rq.type = PTP_CLK_REQ_PEROUT; 38 rq.perout.index = chan; 39 err = ops->enable(ops, &rq, 0); 40 break; 41 case PTP_PF_PHYSYNC: 42 break; 43 default: 44 return -EINVAL; 45 } 46 47 return err; 48 } 49 50 void ptp_disable_all_events(struct ptp_clock *ptp) 51 { 52 struct ptp_clock_info *info = ptp->info; 53 unsigned int i; 54 55 mutex_lock(&ptp->pincfg_mux); 56 /* Disable any pins that may raise EXTTS events */ 57 for (i = 0; i < info->n_pins; i++) 58 if (info->pin_config[i].func == PTP_PF_EXTTS) 59 ptp_disable_pinfunc(info, info->pin_config[i].func, 60 info->pin_config[i].chan); 61 62 /* Disable the PPS event if the driver has PPS support */ 63 if (info->pps) { 64 struct ptp_clock_request req = { .type = PTP_CLK_REQ_PPS }; 65 info->enable(info, &req, 0); 66 } 67 mutex_unlock(&ptp->pincfg_mux); 68 } 69 70 int ptp_set_pinfunc(struct ptp_clock *ptp, unsigned int pin, 71 enum ptp_pin_function func, unsigned int chan) 72 { 73 struct ptp_clock_info *info = ptp->info; 74 struct ptp_pin_desc *pin1 = NULL, *pin2 = &info->pin_config[pin]; 75 unsigned int i; 76 77 /* Check to see if any other pin previously had this function. */ 78 for (i = 0; i < info->n_pins; i++) { 79 if (info->pin_config[i].func == func && 80 info->pin_config[i].chan == chan) { 81 pin1 = &info->pin_config[i]; 82 break; 83 } 84 } 85 if (pin1 && i == pin) 86 return 0; 87 88 /* Check the desired function and channel. */ 89 switch (func) { 90 case PTP_PF_NONE: 91 break; 92 case PTP_PF_EXTTS: 93 if (chan >= info->n_ext_ts) 94 return -EINVAL; 95 break; 96 case PTP_PF_PEROUT: 97 if (chan >= info->n_per_out) 98 return -EINVAL; 99 break; 100 case PTP_PF_PHYSYNC: 101 if (chan != 0) 102 return -EINVAL; 103 break; 104 default: 105 return -EINVAL; 106 } 107 108 if (info->verify(info, pin, func, chan)) { 109 pr_err("driver cannot use function %u and channel %u on pin %u\n", 110 func, chan, pin); 111 return -EOPNOTSUPP; 112 } 113 114 /* Disable whichever pin was previously assigned to this function and 115 * channel. 116 */ 117 if (pin1) { 118 ptp_disable_pinfunc(info, func, chan); 119 pin1->func = PTP_PF_NONE; 120 pin1->chan = 0; 121 } 122 123 /* Disable whatever function was previously assigned to the requested 124 * pin. 125 */ 126 ptp_disable_pinfunc(info, pin2->func, pin2->chan); 127 pin2->func = func; 128 pin2->chan = chan; 129 130 return 0; 131 } 132 133 int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode) 134 { 135 struct ptp_clock *ptp = container_of(pccontext->clk, struct ptp_clock, clock); 136 struct timestamp_event_queue *queue; 137 char debugfsname[32]; 138 139 queue = kzalloc(sizeof(*queue), GFP_KERNEL); 140 if (!queue) 141 return -EINVAL; 142 queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL); 143 if (!queue->mask) { 144 kfree(queue); 145 return -EINVAL; 146 } 147 bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS); 148 spin_lock_init(&queue->lock); 149 scoped_guard(spinlock_irq, &ptp->tsevqs_lock) 150 list_add_tail(&queue->qlist, &ptp->tsevqs); 151 pccontext->private_clkdata = queue; 152 153 /* Debugfs contents */ 154 sprintf(debugfsname, "0x%p", queue); 155 queue->debugfs_instance = 156 debugfs_create_dir(debugfsname, ptp->debugfs_root); 157 queue->dfs_bitmap.array = (u32 *)queue->mask; 158 queue->dfs_bitmap.n_elements = 159 DIV_ROUND_UP(PTP_MAX_CHANNELS, BITS_PER_BYTE * sizeof(u32)); 160 debugfs_create_u32_array("mask", 0444, queue->debugfs_instance, 161 &queue->dfs_bitmap); 162 163 return 0; 164 } 165 166 int ptp_release(struct posix_clock_context *pccontext) 167 { 168 struct timestamp_event_queue *queue = pccontext->private_clkdata; 169 struct ptp_clock *ptp = 170 container_of(pccontext->clk, struct ptp_clock, clock); 171 172 debugfs_remove(queue->debugfs_instance); 173 pccontext->private_clkdata = NULL; 174 scoped_guard(spinlock_irq, &ptp->tsevqs_lock) 175 list_del(&queue->qlist); 176 bitmap_free(queue->mask); 177 kfree(queue); 178 return 0; 179 } 180 181 static long ptp_clock_getcaps(struct ptp_clock *ptp, void __user *arg) 182 { 183 struct ptp_clock_caps caps = { 184 .max_adj = ptp->info->max_adj, 185 .n_alarm = ptp->info->n_alarm, 186 .n_ext_ts = ptp->info->n_ext_ts, 187 .n_per_out = ptp->info->n_per_out, 188 .pps = ptp->info->pps, 189 .n_pins = ptp->info->n_pins, 190 .cross_timestamping = ptp->info->getcrosststamp != NULL, 191 .adjust_phase = ptp->info->adjphase != NULL && 192 ptp->info->getmaxphase != NULL, 193 }; 194 195 if (caps.adjust_phase) 196 caps.max_phase_adj = ptp->info->getmaxphase(ptp->info); 197 198 return copy_to_user(arg, &caps, sizeof(caps)) ? -EFAULT : 0; 199 } 200 201 static long ptp_extts_request(struct ptp_clock *ptp, unsigned int cmd, void __user *arg) 202 { 203 struct ptp_clock_request req = { .type = PTP_CLK_REQ_EXTTS }; 204 struct ptp_clock_info *ops = ptp->info; 205 unsigned int supported_extts_flags; 206 207 if (copy_from_user(&req.extts, arg, sizeof(req.extts))) 208 return -EFAULT; 209 210 if (cmd == PTP_EXTTS_REQUEST2) { 211 /* Tell the drivers to check the flags carefully. */ 212 req.extts.flags |= PTP_STRICT_FLAGS; 213 /* Make sure no reserved bit is set. */ 214 if ((req.extts.flags & ~PTP_EXTTS_VALID_FLAGS) || 215 req.extts.rsv[0] || req.extts.rsv[1]) 216 return -EINVAL; 217 218 /* Ensure one of the rising/falling edge bits is set. */ 219 if ((req.extts.flags & PTP_ENABLE_FEATURE) && 220 (req.extts.flags & PTP_EXTTS_EDGES) == 0) 221 return -EINVAL; 222 } else { 223 req.extts.flags &= PTP_EXTTS_V1_VALID_FLAGS; 224 memset(req.extts.rsv, 0, sizeof(req.extts.rsv)); 225 } 226 227 if (req.extts.index >= ops->n_ext_ts) 228 return -EINVAL; 229 230 supported_extts_flags = ptp->info->supported_extts_flags; 231 /* The PTP_ENABLE_FEATURE flag is always supported. */ 232 supported_extts_flags |= PTP_ENABLE_FEATURE; 233 /* If the driver does not support strictly checking flags, the 234 * PTP_RISING_EDGE and PTP_FALLING_EDGE flags are merely hints 235 * which are not enforced. 236 */ 237 if (!(supported_extts_flags & PTP_STRICT_FLAGS)) 238 supported_extts_flags |= PTP_EXTTS_EDGES; 239 /* Reject unsupported flags */ 240 if (req.extts.flags & ~supported_extts_flags) 241 return -EOPNOTSUPP; 242 243 scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &ptp->pincfg_mux) 244 return ops->enable(ops, &req, req.extts.flags & PTP_ENABLE_FEATURE ? 1 : 0); 245 } 246 247 static long ptp_perout_request(struct ptp_clock *ptp, unsigned int cmd, void __user *arg) 248 { 249 struct ptp_clock_request req = { .type = PTP_CLK_REQ_PEROUT }; 250 struct ptp_perout_request *perout = &req.perout; 251 struct ptp_clock_info *ops = ptp->info; 252 253 if (copy_from_user(perout, arg, sizeof(*perout))) 254 return -EFAULT; 255 256 if (cmd == PTP_PEROUT_REQUEST2) { 257 if (perout->flags & ~PTP_PEROUT_VALID_FLAGS) 258 return -EINVAL; 259 260 /* 261 * The "on" field has undefined meaning if 262 * PTP_PEROUT_DUTY_CYCLE isn't set, we must still treat it 263 * as reserved, which must be set to zero. 264 */ 265 if (!(perout->flags & PTP_PEROUT_DUTY_CYCLE) && 266 !mem_is_zero(perout->rsv, sizeof(perout->rsv))) 267 return -EINVAL; 268 269 if (perout->flags & PTP_PEROUT_DUTY_CYCLE) { 270 /* The duty cycle must be subunitary. */ 271 if (perout->on.sec > perout->period.sec || 272 (perout->on.sec == perout->period.sec && 273 perout->on.nsec > perout->period.nsec)) 274 return -ERANGE; 275 } 276 277 if (perout->flags & PTP_PEROUT_PHASE) { 278 /* 279 * The phase should be specified modulo the period, 280 * therefore anything equal or larger than 1 period 281 * is invalid. 282 */ 283 if (perout->phase.sec > perout->period.sec || 284 (perout->phase.sec == perout->period.sec && 285 perout->phase.nsec >= perout->period.nsec)) 286 return -ERANGE; 287 } 288 } else { 289 perout->flags &= PTP_PEROUT_V1_VALID_FLAGS; 290 memset(perout->rsv, 0, sizeof(perout->rsv)); 291 } 292 293 if (perout->index >= ops->n_per_out) 294 return -EINVAL; 295 if (perout->flags & ~ops->supported_perout_flags) 296 return -EOPNOTSUPP; 297 298 scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &ptp->pincfg_mux) 299 return ops->enable(ops, &req, perout->period.sec || perout->period.nsec); 300 } 301 302 static long ptp_enable_pps(struct ptp_clock *ptp, bool enable) 303 { 304 struct ptp_clock_request req = { .type = PTP_CLK_REQ_PPS }; 305 struct ptp_clock_info *ops = ptp->info; 306 307 if (!capable(CAP_SYS_TIME)) 308 return -EPERM; 309 310 scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &ptp->pincfg_mux) 311 return ops->enable(ops, &req, enable); 312 } 313 314 typedef int (*ptp_crosststamp_fn)(struct ptp_clock_info *, 315 struct system_device_crosststamp *); 316 317 static long ptp_sys_offset_precise(struct ptp_clock *ptp, void __user *arg, 318 ptp_crosststamp_fn crosststamp_fn) 319 { 320 struct ptp_sys_offset_precise precise_offset; 321 struct system_device_crosststamp xtstamp; 322 struct timespec64 ts; 323 int err; 324 325 if (!crosststamp_fn) 326 return -EOPNOTSUPP; 327 328 err = crosststamp_fn(ptp->info, &xtstamp); 329 if (err) 330 return err; 331 332 memset(&precise_offset, 0, sizeof(precise_offset)); 333 ts = ktime_to_timespec64(xtstamp.device); 334 precise_offset.device.sec = ts.tv_sec; 335 precise_offset.device.nsec = ts.tv_nsec; 336 ts = ktime_to_timespec64(xtstamp.sys_realtime); 337 precise_offset.sys_realtime.sec = ts.tv_sec; 338 precise_offset.sys_realtime.nsec = ts.tv_nsec; 339 ts = ktime_to_timespec64(xtstamp.sys_monoraw); 340 precise_offset.sys_monoraw.sec = ts.tv_sec; 341 precise_offset.sys_monoraw.nsec = ts.tv_nsec; 342 343 return copy_to_user(arg, &precise_offset, sizeof(precise_offset)) ? -EFAULT : 0; 344 } 345 346 typedef int (*ptp_gettimex_fn)(struct ptp_clock_info *, 347 struct timespec64 *, 348 struct ptp_system_timestamp *); 349 350 static long ptp_sys_offset_extended(struct ptp_clock *ptp, void __user *arg, 351 ptp_gettimex_fn gettimex_fn) 352 { 353 struct ptp_sys_offset_extended *extoff __free(kfree) = NULL; 354 struct ptp_system_timestamp sts; 355 356 if (!gettimex_fn) 357 return -EOPNOTSUPP; 358 359 extoff = memdup_user(arg, sizeof(*extoff)); 360 if (IS_ERR(extoff)) 361 return PTR_ERR(extoff); 362 363 if (extoff->n_samples > PTP_MAX_SAMPLES || extoff->rsv[0] || extoff->rsv[1]) 364 return -EINVAL; 365 366 switch (extoff->clockid) { 367 case CLOCK_REALTIME: 368 case CLOCK_MONOTONIC: 369 case CLOCK_MONOTONIC_RAW: 370 break; 371 case CLOCK_AUX ... CLOCK_AUX_LAST: 372 if (IS_ENABLED(CONFIG_POSIX_AUX_CLOCKS)) 373 break; 374 fallthrough; 375 default: 376 return -EINVAL; 377 } 378 379 sts.clockid = extoff->clockid; 380 for (unsigned int i = 0; i < extoff->n_samples; i++) { 381 struct timespec64 ts; 382 int err; 383 384 err = gettimex_fn(ptp->info, &ts, &sts); 385 if (err) 386 return err; 387 388 /* Filter out disabled or unavailable clocks */ 389 if (sts.pre_ts.tv_sec < 0 || sts.post_ts.tv_sec < 0) 390 return -EINVAL; 391 392 extoff->ts[i][0].sec = sts.pre_ts.tv_sec; 393 extoff->ts[i][0].nsec = sts.pre_ts.tv_nsec; 394 extoff->ts[i][1].sec = ts.tv_sec; 395 extoff->ts[i][1].nsec = ts.tv_nsec; 396 extoff->ts[i][2].sec = sts.post_ts.tv_sec; 397 extoff->ts[i][2].nsec = sts.post_ts.tv_nsec; 398 } 399 400 return copy_to_user(arg, extoff, sizeof(*extoff)) ? -EFAULT : 0; 401 } 402 403 static long ptp_sys_offset(struct ptp_clock *ptp, void __user *arg) 404 { 405 struct ptp_sys_offset *sysoff __free(kfree) = NULL; 406 struct ptp_clock_time *pct; 407 struct timespec64 ts; 408 409 sysoff = memdup_user(arg, sizeof(*sysoff)); 410 if (IS_ERR(sysoff)) 411 return PTR_ERR(sysoff); 412 413 if (sysoff->n_samples > PTP_MAX_SAMPLES) 414 return -EINVAL; 415 416 pct = &sysoff->ts[0]; 417 for (unsigned int i = 0; i < sysoff->n_samples; i++) { 418 struct ptp_clock_info *ops = ptp->info; 419 int err; 420 421 ktime_get_real_ts64(&ts); 422 pct->sec = ts.tv_sec; 423 pct->nsec = ts.tv_nsec; 424 pct++; 425 if (ops->gettimex64) 426 err = ops->gettimex64(ops, &ts, NULL); 427 else 428 err = ops->gettime64(ops, &ts); 429 if (err) 430 return err; 431 pct->sec = ts.tv_sec; 432 pct->nsec = ts.tv_nsec; 433 pct++; 434 } 435 ktime_get_real_ts64(&ts); 436 pct->sec = ts.tv_sec; 437 pct->nsec = ts.tv_nsec; 438 439 return copy_to_user(arg, sysoff, sizeof(*sysoff)) ? -EFAULT : 0; 440 } 441 442 static long ptp_pin_getfunc(struct ptp_clock *ptp, unsigned int cmd, void __user *arg) 443 { 444 struct ptp_clock_info *ops = ptp->info; 445 struct ptp_pin_desc pd; 446 447 if (copy_from_user(&pd, arg, sizeof(pd))) 448 return -EFAULT; 449 450 if (cmd == PTP_PIN_GETFUNC2 && !mem_is_zero(pd.rsv, sizeof(pd.rsv))) 451 return -EINVAL; 452 453 if (pd.index >= ops->n_pins) 454 return -EINVAL; 455 456 scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &ptp->pincfg_mux) 457 pd = ops->pin_config[array_index_nospec(pd.index, ops->n_pins)]; 458 459 return copy_to_user(arg, &pd, sizeof(pd)) ? -EFAULT : 0; 460 } 461 462 static long ptp_pin_setfunc(struct ptp_clock *ptp, unsigned int cmd, void __user *arg) 463 { 464 struct ptp_clock_info *ops = ptp->info; 465 struct ptp_pin_desc pd; 466 unsigned int pin_index; 467 468 if (copy_from_user(&pd, arg, sizeof(pd))) 469 return -EFAULT; 470 471 if (cmd == PTP_PIN_SETFUNC2 && !mem_is_zero(pd.rsv, sizeof(pd.rsv))) 472 return -EINVAL; 473 474 if (pd.index >= ops->n_pins) 475 return -EINVAL; 476 477 pin_index = array_index_nospec(pd.index, ops->n_pins); 478 scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &ptp->pincfg_mux) 479 return ptp_set_pinfunc(ptp, pin_index, pd.func, pd.chan); 480 } 481 482 static long ptp_mask_clear_all(struct timestamp_event_queue *tsevq) 483 { 484 bitmap_clear(tsevq->mask, 0, PTP_MAX_CHANNELS); 485 return 0; 486 } 487 488 static long ptp_mask_en_single(struct timestamp_event_queue *tsevq, void __user *arg) 489 { 490 unsigned int channel; 491 492 if (copy_from_user(&channel, arg, sizeof(channel))) 493 return -EFAULT; 494 if (channel >= PTP_MAX_CHANNELS) 495 return -EFAULT; 496 set_bit(channel, tsevq->mask); 497 return 0; 498 } 499 500 long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd, 501 unsigned long arg) 502 { 503 struct ptp_clock *ptp = container_of(pccontext->clk, struct ptp_clock, clock); 504 void __user *argptr; 505 506 if (in_compat_syscall() && cmd != PTP_ENABLE_PPS && cmd != PTP_ENABLE_PPS2) 507 arg = (unsigned long)compat_ptr(arg); 508 argptr = (void __force __user *)arg; 509 510 switch (cmd) { 511 case PTP_CLOCK_GETCAPS: 512 case PTP_CLOCK_GETCAPS2: 513 return ptp_clock_getcaps(ptp, argptr); 514 515 case PTP_EXTTS_REQUEST: 516 case PTP_EXTTS_REQUEST2: 517 if ((pccontext->fp->f_mode & FMODE_WRITE) == 0) 518 return -EACCES; 519 return ptp_extts_request(ptp, cmd, argptr); 520 521 case PTP_PEROUT_REQUEST: 522 case PTP_PEROUT_REQUEST2: 523 if ((pccontext->fp->f_mode & FMODE_WRITE) == 0) 524 return -EACCES; 525 return ptp_perout_request(ptp, cmd, argptr); 526 527 case PTP_ENABLE_PPS: 528 case PTP_ENABLE_PPS2: 529 if ((pccontext->fp->f_mode & FMODE_WRITE) == 0) 530 return -EACCES; 531 return ptp_enable_pps(ptp, !!arg); 532 533 case PTP_SYS_OFFSET_PRECISE: 534 case PTP_SYS_OFFSET_PRECISE2: 535 return ptp_sys_offset_precise(ptp, argptr, 536 ptp->info->getcrosststamp); 537 538 case PTP_SYS_OFFSET_EXTENDED: 539 case PTP_SYS_OFFSET_EXTENDED2: 540 return ptp_sys_offset_extended(ptp, argptr, 541 ptp->info->gettimex64); 542 543 case PTP_SYS_OFFSET: 544 case PTP_SYS_OFFSET2: 545 return ptp_sys_offset(ptp, argptr); 546 547 case PTP_PIN_GETFUNC: 548 case PTP_PIN_GETFUNC2: 549 return ptp_pin_getfunc(ptp, cmd, argptr); 550 551 case PTP_PIN_SETFUNC: 552 case PTP_PIN_SETFUNC2: 553 if ((pccontext->fp->f_mode & FMODE_WRITE) == 0) 554 return -EACCES; 555 return ptp_pin_setfunc(ptp, cmd, argptr); 556 557 case PTP_MASK_CLEAR_ALL: 558 return ptp_mask_clear_all(pccontext->private_clkdata); 559 560 case PTP_MASK_EN_SINGLE: 561 return ptp_mask_en_single(pccontext->private_clkdata, argptr); 562 563 case PTP_SYS_OFFSET_PRECISE_CYCLES: 564 return ptp_sys_offset_precise(ptp, argptr, 565 ptp->info->getcrosscycles); 566 567 case PTP_SYS_OFFSET_EXTENDED_CYCLES: 568 return ptp_sys_offset_extended(ptp, argptr, 569 ptp->info->getcyclesx64); 570 default: 571 return -ENOTTY; 572 } 573 } 574 575 __poll_t ptp_poll(struct posix_clock_context *pccontext, struct file *fp, 576 poll_table *wait) 577 { 578 struct ptp_clock *ptp = 579 container_of(pccontext->clk, struct ptp_clock, clock); 580 struct timestamp_event_queue *queue; 581 582 queue = pccontext->private_clkdata; 583 if (!queue) 584 return EPOLLERR; 585 586 poll_wait(fp, &ptp->tsev_wq, wait); 587 588 return queue_cnt(queue) ? EPOLLIN : 0; 589 } 590 591 #define EXTTS_BUFSIZE (PTP_BUF_TIMESTAMPS * sizeof(struct ptp_extts_event)) 592 593 ssize_t ptp_read(struct posix_clock_context *pccontext, uint rdflags, 594 char __user *buf, size_t cnt) 595 { 596 struct ptp_clock *ptp = container_of(pccontext->clk, struct ptp_clock, clock); 597 struct timestamp_event_queue *queue; 598 struct ptp_extts_event *event; 599 ssize_t result; 600 601 queue = pccontext->private_clkdata; 602 if (!queue) 603 return -EINVAL; 604 605 if (cnt % sizeof(*event) != 0) 606 return -EINVAL; 607 608 if (cnt > EXTTS_BUFSIZE) 609 cnt = EXTTS_BUFSIZE; 610 611 if (wait_event_interruptible(ptp->tsev_wq, ptp->defunct || queue_cnt(queue))) 612 return -ERESTARTSYS; 613 614 if (ptp->defunct) 615 return -ENODEV; 616 617 event = kmalloc(EXTTS_BUFSIZE, GFP_KERNEL); 618 if (!event) 619 return -ENOMEM; 620 621 scoped_guard(spinlock_irq, &queue->lock) { 622 size_t qcnt = min((size_t)queue_cnt(queue), cnt / sizeof(*event)); 623 624 for (size_t i = 0; i < qcnt; i++) { 625 event[i] = queue->buf[queue->head]; 626 /* Paired with READ_ONCE() in queue_cnt() */ 627 WRITE_ONCE(queue->head, (queue->head + 1) % PTP_MAX_TIMESTAMPS); 628 } 629 cnt = qcnt * sizeof(*event); 630 } 631 632 result = cnt; 633 if (copy_to_user(buf, event, cnt)) 634 result = -EFAULT; 635 636 kfree(event); 637 return result; 638 } 639