drivers/ptp/ptp_clock.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * PTP 1588 clock support
   4  *
   5  * Copyright (C) 2010 OMICRON electronics GmbH
   6  */
   7 #include <linux/idr.h>
   8 #include <linux/device.h>
   9 #include <linux/err.h>
  10 #include <linux/init.h>
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/posix-clock.h>
  14 #include <linux/pps_kernel.h>
  15 #include <linux/slab.h>
  16 #include <linux/syscalls.h>
  17 #include <linux/uaccess.h>
  18 #include <uapi/linux/sched/types.h>
  19
  20 #include "ptp_private.h"
  21
  22 #define PTP_MAX_ALARMS 4
  23 #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
  24 #define PTP_PPS_EVENT PPS_CAPTUREASSERT
  25 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
  26
  27 struct class *ptp_class;
  28
  29 /* private globals */
  30
  31 static dev_t ptp_devt;
  32
  33 static DEFINE_IDA(ptp_clocks_map);
  34
  35 /* time stamp event queue operations */
  36
  37 static inline int queue_free(struct timestamp_event_queue *q)
  38 {
  39         return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
  40 }
  41
  42 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
  43                                        struct ptp_clock_event *src)
  44 {
  45         struct ptp_extts_event *dst;
  46         unsigned long flags;
  47         s64 seconds;
  48         u32 remainder;
  49
  50         seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
  51
  52         spin_lock_irqsave(&queue->lock, flags);
  53
  54         dst = &queue->buf[queue->tail];
  55         dst->index = src->index;
  56         dst->t.sec = seconds;
  57         dst->t.nsec = remainder;
  58
  59         /* Both WRITE_ONCE() are paired with READ_ONCE() in queue_cnt() */
  60         if (!queue_free(queue))
  61                 WRITE_ONCE(queue->head, (queue->head + 1) % PTP_MAX_TIMESTAMPS);
  62
  63         WRITE_ONCE(queue->tail, (queue->tail + 1) % PTP_MAX_TIMESTAMPS);
  64
  65         spin_unlock_irqrestore(&queue->lock, flags);
  66 }
  67
  68 /* posix clock implementation */
  69
  70 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
  71 {
  72         tp->tv_sec = 0;
  73         tp->tv_nsec = 1;
  74         return 0;
  75 }
  76
  77 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
  78 {
  79         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
  80
  81         if (ptp_clock_freerun(ptp)) {
  82                 pr_err("ptp: physical clock is free running\n");
  83                 return -EBUSY;
  84         }
  85
  86         return  ptp->info->settime64(ptp->info, tp);
  87 }
  88
  89 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
  90 {
  91         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
  92         int err;
  93
  94         if (ptp->info->gettimex64)
  95                 err = ptp->info->gettimex64(ptp->info, tp, NULL);
  96         else
  97                 err = ptp->info->gettime64(ptp->info, tp);
  98         return err;
  99 }
 100
 101 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
 102 {
 103         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 104         struct ptp_clock_info *ops;
 105         int err = -EOPNOTSUPP;
 106
 107         if (ptp_clock_freerun(ptp)) {
 108                 pr_err("ptp: physical clock is free running\n");
 109                 return -EBUSY;
 110         }
 111
 112         ops = ptp->info;
 113
 114         if (tx->modes & ADJ_SETOFFSET) {
 115                 struct timespec64 ts;
 116                 ktime_t kt;
 117                 s64 delta;
 118
 119                 ts.tv_sec  = tx->time.tv_sec;
 120                 ts.tv_nsec = tx->time.tv_usec;
 121
 122                 if (!(tx->modes & ADJ_NANO))
 123                         ts.tv_nsec *= 1000;
 124
 125                 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
 126                         return -EINVAL;
 127
 128                 kt = timespec64_to_ktime(ts);
 129                 delta = ktime_to_ns(kt);
 130                 err = ops->adjtime(ops, delta);
 131         } else if (tx->modes & ADJ_FREQUENCY) {
 132                 long ppb = scaled_ppm_to_ppb(tx->freq);
 133                 if (ppb > ops->max_adj || ppb < -ops->max_adj)
 134                         return -ERANGE;
 135                 err = ops->adjfine(ops, tx->freq);
 136                 ptp->dialed_frequency = tx->freq;
 137         } else if (tx->modes & ADJ_OFFSET) {
 138                 if (ops->adjphase) {
 139                         s32 max_phase_adj = ops->getmaxphase(ops);
 140                         s32 offset = tx->offset;
 141
 142                         if (!(tx->modes & ADJ_NANO))
 143                                 offset *= NSEC_PER_USEC;
 144
 145                         if (offset > max_phase_adj || offset < -max_phase_adj)
 146                                 return -ERANGE;
 147
 148                         err = ops->adjphase(ops, offset);
 149                 }
 150         } else if (tx->modes == 0) {
 151                 tx->freq = ptp->dialed_frequency;
 152                 err = 0;
 153         }
 154
 155         return err;
 156 }
 157
 158 static struct posix_clock_operations ptp_clock_ops = {
 159         .owner          = THIS_MODULE,
 160         .clock_adjtime  = ptp_clock_adjtime,
 161         .clock_gettime  = ptp_clock_gettime,
 162         .clock_getres   = ptp_clock_getres,
 163         .clock_settime  = ptp_clock_settime,
 164         .ioctl          = ptp_ioctl,
 165         .open           = ptp_open,
 166         .poll           = ptp_poll,
 167         .read           = ptp_read,
 168 };
 169
 170 static void ptp_clock_release(struct device *dev)
 171 {
 172         struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
 173
 174         ptp_cleanup_pin_groups(ptp);
 175         kfree(ptp->vclock_index);
 176         mutex_destroy(&ptp->tsevq_mux);
 177         mutex_destroy(&ptp->pincfg_mux);
 178         mutex_destroy(&ptp->n_vclocks_mux);
 179         ida_free(&ptp_clocks_map, ptp->index);
 180         kfree(ptp);
 181 }
 182
 183 static int ptp_getcycles64(struct ptp_clock_info *info, struct timespec64 *ts)
 184 {
 185         if (info->getcyclesx64)
 186                 return info->getcyclesx64(info, ts, NULL);
 187         else
 188                 return info->gettime64(info, ts);
 189 }
 190
 191 static void ptp_aux_kworker(struct kthread_work *work)
 192 {
 193         struct ptp_clock *ptp = container_of(work, struct ptp_clock,
 194                                              aux_work.work);
 195         struct ptp_clock_info *info = ptp->info;
 196         long delay;
 197
 198         delay = info->do_aux_work(info);
 199
 200         if (delay >= 0)
 201                 kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
 202 }
 203
 204 /* public interface */
 205
 206 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 207                                      struct device *parent)
 208 {
 209         struct ptp_clock *ptp;
 210         int err = 0, index, major = MAJOR(ptp_devt);
 211         size_t size;
 212
 213         if (info->n_alarm > PTP_MAX_ALARMS)
 214                 return ERR_PTR(-EINVAL);
 215
 216         /* Initialize a clock structure. */
 217         err = -ENOMEM;
 218         ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
 219         if (ptp == NULL)
 220                 goto no_memory;
 221
 222         index = ida_alloc_max(&ptp_clocks_map, MINORMASK, GFP_KERNEL);
 223         if (index < 0) {
 224                 err = index;
 225                 goto no_slot;
 226         }
 227
 228         ptp->clock.ops = ptp_clock_ops;
 229         ptp->info = info;
 230         ptp->devid = MKDEV(major, index);
 231         ptp->index = index;
 232         spin_lock_init(&ptp->tsevq.lock);
 233         mutex_init(&ptp->tsevq_mux);
 234         mutex_init(&ptp->pincfg_mux);
 235         mutex_init(&ptp->n_vclocks_mux);
 236         init_waitqueue_head(&ptp->tsev_wq);
 237
 238         if (ptp->info->getcycles64 || ptp->info->getcyclesx64) {
 239                 ptp->has_cycles = true;
 240                 if (!ptp->info->getcycles64 && ptp->info->getcyclesx64)
 241                         ptp->info->getcycles64 = ptp_getcycles64;
 242         } else {
 243                 /* Free running cycle counter not supported, use time. */
 244                 ptp->info->getcycles64 = ptp_getcycles64;
 245
 246                 if (ptp->info->gettimex64)
 247                         ptp->info->getcyclesx64 = ptp->info->gettimex64;
 248
 249                 if (ptp->info->getcrosststamp)
 250                         ptp->info->getcrosscycles = ptp->info->getcrosststamp;
 251         }
 252
 253         if (ptp->info->do_aux_work) {
 254                 kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
 255                 ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
 256                 if (IS_ERR(ptp->kworker)) {
 257                         err = PTR_ERR(ptp->kworker);
 258                         pr_err("failed to create ptp aux_worker %d\n", err);
 259                         goto kworker_err;
 260                 }
 261         }
 262
 263         /* PTP virtual clock is being registered under physical clock */
 264         if (parent && parent->class && parent->class->name &&
 265             strcmp(parent->class->name, "ptp") == 0)
 266                 ptp->is_virtual_clock = true;
 267
 268         if (!ptp->is_virtual_clock) {
 269                 ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
 270
 271                 size = sizeof(int) * ptp->max_vclocks;
 272                 ptp->vclock_index = kzalloc(size, GFP_KERNEL);
 273                 if (!ptp->vclock_index) {
 274                         err = -ENOMEM;
 275                         goto no_mem_for_vclocks;
 276                 }
 277         }
 278
 279         err = ptp_populate_pin_groups(ptp);
 280         if (err)
 281                 goto no_pin_groups;
 282
 283         /* Register a new PPS source. */
 284         if (info->pps) {
 285                 struct pps_source_info pps;
 286                 memset(&pps, 0, sizeof(pps));
 287                 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
 288                 pps.mode = PTP_PPS_MODE;
 289                 pps.owner = info->owner;
 290                 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
 291                 if (IS_ERR(ptp->pps_source)) {
 292                         err = PTR_ERR(ptp->pps_source);
 293                         pr_err("failed to register pps source\n");
 294                         goto no_pps;
 295                 }
 296                 ptp->pps_source->lookup_cookie = ptp;
 297         }
 298
 299         /* Initialize a new device of our class in our clock structure. */
 300         device_initialize(&ptp->dev);
 301         ptp->dev.devt = ptp->devid;
 302         ptp->dev.class = ptp_class;
 303         ptp->dev.parent = parent;
 304         ptp->dev.groups = ptp->pin_attr_groups;
 305         ptp->dev.release = ptp_clock_release;
 306         dev_set_drvdata(&ptp->dev, ptp);
 307         dev_set_name(&ptp->dev, "ptp%d", ptp->index);
 308
 309         /* Create a posix clock and link it to the device. */
 310         err = posix_clock_register(&ptp->clock, &ptp->dev);
 311         if (err) {
 312                 if (ptp->pps_source)
 313                         pps_unregister_source(ptp->pps_source);
 314
 315                 if (ptp->kworker)
 316                         kthread_destroy_worker(ptp->kworker);
 317
 318                 put_device(&ptp->dev);
 319
 320                 pr_err("failed to create posix clock\n");
 321                 return ERR_PTR(err);
 322         }
 323
 324         return ptp;
 325
 326 no_pps:
 327         ptp_cleanup_pin_groups(ptp);
 328 no_pin_groups:
 329         kfree(ptp->vclock_index);
 330 no_mem_for_vclocks:
 331         if (ptp->kworker)
 332                 kthread_destroy_worker(ptp->kworker);
 333 kworker_err:
 334         mutex_destroy(&ptp->tsevq_mux);
 335         mutex_destroy(&ptp->pincfg_mux);
 336         mutex_destroy(&ptp->n_vclocks_mux);
 337         ida_free(&ptp_clocks_map, index);
 338 no_slot:
 339         kfree(ptp);
 340 no_memory:
 341         return ERR_PTR(err);
 342 }
 343 EXPORT_SYMBOL(ptp_clock_register);
 344
 345 static int unregister_vclock(struct device *dev, void *data)
 346 {
 347         struct ptp_clock *ptp = dev_get_drvdata(dev);
 348
 349         ptp_vclock_unregister(info_to_vclock(ptp->info));
 350         return 0;
 351 }
 352
 353 int ptp_clock_unregister(struct ptp_clock *ptp)
 354 {
 355         if (ptp_vclock_in_use(ptp)) {
 356                 device_for_each_child(&ptp->dev, NULL, unregister_vclock);
 357         }
 358
 359         ptp->defunct = 1;
 360         wake_up_interruptible(&ptp->tsev_wq);
 361
 362         if (ptp->kworker) {
 363                 kthread_cancel_delayed_work_sync(&ptp->aux_work);
 364                 kthread_destroy_worker(ptp->kworker);
 365         }
 366
 367         /* Release the clock's resources. */
 368         if (ptp->pps_source)
 369                 pps_unregister_source(ptp->pps_source);
 370
 371         posix_clock_unregister(&ptp->clock);
 372
 373         return 0;
 374 }
 375 EXPORT_SYMBOL(ptp_clock_unregister);
 376
 377 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
 378 {
 379         struct pps_event_time evt;
 380
 381         switch (event->type) {
 382
 383         case PTP_CLOCK_ALARM:
 384                 break;
 385
 386         case PTP_CLOCK_EXTTS:
 387                 enqueue_external_timestamp(&ptp->tsevq, event);
 388                 wake_up_interruptible(&ptp->tsev_wq);
 389                 break;
 390
 391         case PTP_CLOCK_PPS:
 392                 pps_get_ts(&evt);
 393                 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
 394                 break;
 395
 396         case PTP_CLOCK_PPSUSR:
 397                 pps_event(ptp->pps_source, &event->pps_times,
 398                           PTP_PPS_EVENT, NULL);
 399                 break;
 400         }
 401 }
 402 EXPORT_SYMBOL(ptp_clock_event);
 403
 404 int ptp_clock_index(struct ptp_clock *ptp)
 405 {
 406         return ptp->index;
 407 }
 408 EXPORT_SYMBOL(ptp_clock_index);
 409
 410 int ptp_find_pin(struct ptp_clock *ptp,
 411                  enum ptp_pin_function func, unsigned int chan)
 412 {
 413         struct ptp_pin_desc *pin = NULL;
 414         int i;
 415
 416         for (i = 0; i < ptp->info->n_pins; i++) {
 417                 if (ptp->info->pin_config[i].func == func &&
 418                     ptp->info->pin_config[i].chan == chan) {
 419                         pin = &ptp->info->pin_config[i];
 420                         break;
 421                 }
 422         }
 423
 424         return pin ? i : -1;
 425 }
 426 EXPORT_SYMBOL(ptp_find_pin);
 427
 428 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
 429                           enum ptp_pin_function func, unsigned int chan)
 430 {
 431         int result;
 432
 433         mutex_lock(&ptp->pincfg_mux);
 434
 435         result = ptp_find_pin(ptp, func, chan);
 436
 437         mutex_unlock(&ptp->pincfg_mux);
 438
 439         return result;
 440 }
 441 EXPORT_SYMBOL(ptp_find_pin_unlocked);
 442
 443 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
 444 {
 445         return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
 446 }
 447 EXPORT_SYMBOL(ptp_schedule_worker);
 448
 449 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
 450 {
 451         kthread_cancel_delayed_work_sync(&ptp->aux_work);
 452 }
 453 EXPORT_SYMBOL(ptp_cancel_worker_sync);
 454
 455 /* module operations */
 456
 457 static void __exit ptp_exit(void)
 458 {
 459         class_destroy(ptp_class);
 460         unregister_chrdev_region(ptp_devt, MINORMASK + 1);
 461         ida_destroy(&ptp_clocks_map);
 462 }
 463
 464 static int __init ptp_init(void)
 465 {
 466         int err;
 467
 468         ptp_class = class_create("ptp");
 469         if (IS_ERR(ptp_class)) {
 470                 pr_err("ptp: failed to allocate class\n");
 471                 return PTR_ERR(ptp_class);
 472         }
 473
 474         err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
 475         if (err < 0) {
 476                 pr_err("ptp: failed to allocate device region\n");
 477                 goto no_region;
 478         }
 479
 480         ptp_class->dev_groups = ptp_groups;
 481         pr_info("PTP clock support registered\n");
 482         return 0;
 483
 484 no_region:
 485         class_destroy(ptp_class);
 486         return err;
 487 }
 488
 489 subsys_initcall(ptp_init);
 490 module_exit(ptp_exit);
 491
 492 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
 493 MODULE_DESCRIPTION("PTP clocks support");
 494 MODULE_LICENSE("GPL");