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