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