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