drivers/ptp/ptp_clock.c

   1 /*
   2  * PTP 1588 clock support
   3  *
   4  * Copyright (C) 2010 OMICRON electronics GmbH
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20 #include <linux/idr.h>
  21 #include <linux/device.h>
  22 #include <linux/err.h>
  23 #include <linux/init.h>
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/posix-clock.h>
  27 #include <linux/pps_kernel.h>
  28 #include <linux/slab.h>
  29 #include <linux/syscalls.h>
  30 #include <linux/uaccess.h>
  31 #include <uapi/linux/sched/types.h>
  32
  33 #include "ptp_private.h"
  34
  35 #define PTP_MAX_ALARMS 4
  36 #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
  37 #define PTP_PPS_EVENT PPS_CAPTUREASSERT
  38 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
  39
  40 /* private globals */
  41
  42 static dev_t ptp_devt;
  43 static struct class *ptp_class;
  44
  45 static DEFINE_IDA(ptp_clocks_map);
  46
  47 /* time stamp event queue operations */
  48
  49 static inline int queue_free(struct timestamp_event_queue *q)
  50 {
  51         return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
  52 }
  53
  54 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
  55                                        struct ptp_clock_event *src)
  56 {
  57         struct ptp_extts_event *dst;
  58         unsigned long flags;
  59         s64 seconds;
  60         u32 remainder;
  61
  62         seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
  63
  64         spin_lock_irqsave(&queue->lock, flags);
  65
  66         dst = &queue->buf[queue->tail];
  67         dst->index = src->index;
  68         dst->t.sec = seconds;
  69         dst->t.nsec = remainder;
  70
  71         if (!queue_free(queue))
  72                 queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
  73
  74         queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;
  75
  76         spin_unlock_irqrestore(&queue->lock, flags);
  77 }
  78
  79 static s32 scaled_ppm_to_ppb(long ppm)
  80 {
  81         /*
  82          * The 'freq' field in the 'struct timex' is in parts per
  83          * million, but with a 16 bit binary fractional field.
  84          *
  85          * We want to calculate
  86          *
  87          *    ppb = scaled_ppm * 1000 / 2^16
  88          *
  89          * which simplifies to
  90          *
  91          *    ppb = scaled_ppm * 125 / 2^13
  92          */
  93         s64 ppb = 1 + ppm;
  94         ppb *= 125;
  95         ppb >>= 13;
  96         return (s32) ppb;
  97 }
  98
  99 /* posix clock implementation */
 100
 101 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
 102 {
 103         tp->tv_sec = 0;
 104         tp->tv_nsec = 1;
 105         return 0;
 106 }
 107
 108 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
 109 {
 110         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 111
 112         return  ptp->info->settime64(ptp->info, tp);
 113 }
 114
 115 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
 116 {
 117         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 118         int err;
 119
 120         if (ptp->info->gettimex64)
 121                 err = ptp->info->gettimex64(ptp->info, tp, NULL);
 122         else
 123                 err = ptp->info->gettime64(ptp->info, tp);
 124         return err;
 125 }
 126
 127 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
 128 {
 129         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 130         struct ptp_clock_info *ops;
 131         int err = -EOPNOTSUPP;
 132
 133         ops = ptp->info;
 134
 135         if (tx->modes & ADJ_SETOFFSET) {
 136                 struct timespec64 ts;
 137                 ktime_t kt;
 138                 s64 delta;
 139
 140                 ts.tv_sec  = tx->time.tv_sec;
 141                 ts.tv_nsec = tx->time.tv_usec;
 142
 143                 if (!(tx->modes & ADJ_NANO))
 144                         ts.tv_nsec *= 1000;
 145
 146                 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
 147                         return -EINVAL;
 148
 149                 kt = timespec64_to_ktime(ts);
 150                 delta = ktime_to_ns(kt);
 151                 err = ops->adjtime(ops, delta);
 152         } else if (tx->modes & ADJ_FREQUENCY) {
 153                 s32 ppb = scaled_ppm_to_ppb(tx->freq);
 154                 if (ppb > ops->max_adj || ppb < -ops->max_adj)
 155                         return -ERANGE;
 156                 if (ops->adjfine)
 157                         err = ops->adjfine(ops, tx->freq);
 158                 else
 159                         err = ops->adjfreq(ops, ppb);
 160                 ptp->dialed_frequency = tx->freq;
 161         } else if (tx->modes == 0) {
 162                 tx->freq = ptp->dialed_frequency;
 163                 err = 0;
 164         }
 165
 166         return err;
 167 }
 168
 169 static struct posix_clock_operations ptp_clock_ops = {
 170         .owner          = THIS_MODULE,
 171         .clock_adjtime  = ptp_clock_adjtime,
 172         .clock_gettime  = ptp_clock_gettime,
 173         .clock_getres   = ptp_clock_getres,
 174         .clock_settime  = ptp_clock_settime,
 175         .ioctl          = ptp_ioctl,
 176         .open           = ptp_open,
 177         .poll           = ptp_poll,
 178         .read           = ptp_read,
 179 };
 180
 181 static void delete_ptp_clock(struct posix_clock *pc)
 182 {
 183         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 184
 185         mutex_destroy(&ptp->tsevq_mux);
 186         mutex_destroy(&ptp->pincfg_mux);
 187         ida_simple_remove(&ptp_clocks_map, ptp->index);
 188         kfree(ptp);
 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
 212         if (info->n_alarm > PTP_MAX_ALARMS)
 213                 return ERR_PTR(-EINVAL);
 214
 215         /* Initialize a clock structure. */
 216         err = -ENOMEM;
 217         ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
 218         if (ptp == NULL)
 219                 goto no_memory;
 220
 221         index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
 222         if (index < 0) {
 223                 err = index;
 224                 goto no_slot;
 225         }
 226
 227         ptp->clock.ops = ptp_clock_ops;
 228         ptp->clock.release = delete_ptp_clock;
 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         init_waitqueue_head(&ptp->tsev_wq);
 236
 237         if (ptp->info->do_aux_work) {
 238                 kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
 239                 ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
 240                 if (IS_ERR(ptp->kworker)) {
 241                         err = PTR_ERR(ptp->kworker);
 242                         pr_err("failed to create ptp aux_worker %d\n", err);
 243                         goto kworker_err;
 244                 }
 245         }
 246
 247         err = ptp_populate_pin_groups(ptp);
 248         if (err)
 249                 goto no_pin_groups;
 250
 251         /* Create a new device in our class. */
 252         ptp->dev = device_create_with_groups(ptp_class, parent, ptp->devid,
 253                                              ptp, ptp->pin_attr_groups,
 254                                              "ptp%d", ptp->index);
 255         if (IS_ERR(ptp->dev)) {
 256                 err = PTR_ERR(ptp->dev);
 257                 goto no_device;
 258         }
 259
 260         /* Register a new PPS source. */
 261         if (info->pps) {
 262                 struct pps_source_info pps;
 263                 memset(&pps, 0, sizeof(pps));
 264                 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
 265                 pps.mode = PTP_PPS_MODE;
 266                 pps.owner = info->owner;
 267                 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
 268                 if (IS_ERR(ptp->pps_source)) {
 269                         err = PTR_ERR(ptp->pps_source);
 270                         pr_err("failed to register pps source\n");
 271                         goto no_pps;
 272                 }
 273         }
 274
 275         /* Create a posix clock. */
 276         err = posix_clock_register(&ptp->clock, ptp->devid);
 277         if (err) {
 278                 pr_err("failed to create posix clock\n");
 279                 goto no_clock;
 280         }
 281
 282         return ptp;
 283
 284 no_clock:
 285         if (ptp->pps_source)
 286                 pps_unregister_source(ptp->pps_source);
 287 no_pps:
 288         device_destroy(ptp_class, ptp->devid);
 289 no_device:
 290         ptp_cleanup_pin_groups(ptp);
 291 no_pin_groups:
 292         if (ptp->kworker)
 293                 kthread_destroy_worker(ptp->kworker);
 294 kworker_err:
 295         mutex_destroy(&ptp->tsevq_mux);
 296         mutex_destroy(&ptp->pincfg_mux);
 297         ida_simple_remove(&ptp_clocks_map, index);
 298 no_slot:
 299         kfree(ptp);
 300 no_memory:
 301         return ERR_PTR(err);
 302 }
 303 EXPORT_SYMBOL(ptp_clock_register);
 304
 305 int ptp_clock_unregister(struct ptp_clock *ptp)
 306 {
 307         ptp->defunct = 1;
 308         wake_up_interruptible(&ptp->tsev_wq);
 309
 310         if (ptp->kworker) {
 311                 kthread_cancel_delayed_work_sync(&ptp->aux_work);
 312                 kthread_destroy_worker(ptp->kworker);
 313         }
 314
 315         /* Release the clock's resources. */
 316         if (ptp->pps_source)
 317                 pps_unregister_source(ptp->pps_source);
 318
 319         device_destroy(ptp_class, ptp->devid);
 320         ptp_cleanup_pin_groups(ptp);
 321
 322         posix_clock_unregister(&ptp->clock);
 323         return 0;
 324 }
 325 EXPORT_SYMBOL(ptp_clock_unregister);
 326
 327 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
 328 {
 329         struct pps_event_time evt;
 330
 331         switch (event->type) {
 332
 333         case PTP_CLOCK_ALARM:
 334                 break;
 335
 336         case PTP_CLOCK_EXTTS:
 337                 enqueue_external_timestamp(&ptp->tsevq, event);
 338                 wake_up_interruptible(&ptp->tsev_wq);
 339                 break;
 340
 341         case PTP_CLOCK_PPS:
 342                 pps_get_ts(&evt);
 343                 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
 344                 break;
 345
 346         case PTP_CLOCK_PPSUSR:
 347                 pps_event(ptp->pps_source, &event->pps_times,
 348                           PTP_PPS_EVENT, NULL);
 349                 break;
 350         }
 351 }
 352 EXPORT_SYMBOL(ptp_clock_event);
 353
 354 int ptp_clock_index(struct ptp_clock *ptp)
 355 {
 356         return ptp->index;
 357 }
 358 EXPORT_SYMBOL(ptp_clock_index);
 359
 360 int ptp_find_pin(struct ptp_clock *ptp,
 361                  enum ptp_pin_function func, unsigned int chan)
 362 {
 363         struct ptp_pin_desc *pin = NULL;
 364         int i;
 365
 366         mutex_lock(&ptp->pincfg_mux);
 367         for (i = 0; i < ptp->info->n_pins; i++) {
 368                 if (ptp->info->pin_config[i].func == func &&
 369                     ptp->info->pin_config[i].chan == chan) {
 370                         pin = &ptp->info->pin_config[i];
 371                         break;
 372                 }
 373         }
 374         mutex_unlock(&ptp->pincfg_mux);
 375
 376         return pin ? i : -1;
 377 }
 378 EXPORT_SYMBOL(ptp_find_pin);
 379
 380 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
 381 {
 382         return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
 383 }
 384 EXPORT_SYMBOL(ptp_schedule_worker);
 385
 386 /* module operations */
 387
 388 static void __exit ptp_exit(void)
 389 {
 390         class_destroy(ptp_class);
 391         unregister_chrdev_region(ptp_devt, MINORMASK + 1);
 392         ida_destroy(&ptp_clocks_map);
 393 }
 394
 395 static int __init ptp_init(void)
 396 {
 397         int err;
 398
 399         ptp_class = class_create(THIS_MODULE, "ptp");
 400         if (IS_ERR(ptp_class)) {
 401                 pr_err("ptp: failed to allocate class\n");
 402                 return PTR_ERR(ptp_class);
 403         }
 404
 405         err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
 406         if (err < 0) {
 407                 pr_err("ptp: failed to allocate device region\n");
 408                 goto no_region;
 409         }
 410
 411         ptp_class->dev_groups = ptp_groups;
 412         pr_info("PTP clock support registered\n");
 413         return 0;
 414
 415 no_region:
 416         class_destroy(ptp_class);
 417         return err;
 418 }
 419
 420 subsys_initcall(ptp_init);
 421 module_exit(ptp_exit);
 422
 423 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
 424 MODULE_DESCRIPTION("PTP clocks support");
 425 MODULE_LICENSE("GPL");