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         err = ptp->info->gettime64(ptp->info, tp);
 121         return err;
 122 }
 123
 124 static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx)
 125 {
 126         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 127         struct ptp_clock_info *ops;
 128         int err = -EOPNOTSUPP;
 129
 130         ops = ptp->info;
 131
 132         if (tx->modes & ADJ_SETOFFSET) {
 133                 struct timespec64 ts;
 134                 ktime_t kt;
 135                 s64 delta;
 136
 137                 ts.tv_sec  = tx->time.tv_sec;
 138                 ts.tv_nsec = tx->time.tv_usec;
 139
 140                 if (!(tx->modes & ADJ_NANO))
 141                         ts.tv_nsec *= 1000;
 142
 143                 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
 144                         return -EINVAL;
 145
 146                 kt = timespec64_to_ktime(ts);
 147                 delta = ktime_to_ns(kt);
 148                 err = ops->adjtime(ops, delta);
 149         } else if (tx->modes & ADJ_FREQUENCY) {
 150                 s32 ppb = scaled_ppm_to_ppb(tx->freq);
 151                 if (ppb > ops->max_adj || ppb < -ops->max_adj)
 152                         return -ERANGE;
 153                 if (ops->adjfine)
 154                         err = ops->adjfine(ops, tx->freq);
 155                 else
 156                         err = ops->adjfreq(ops, ppb);
 157                 ptp->dialed_frequency = tx->freq;
 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                 char *worker_name = kasprintf(GFP_KERNEL, "ptp%d", ptp->index);
 236
 237                 kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
 238                 ptp->kworker = kthread_create_worker(0, worker_name ?
 239                                                      worker_name : info->name);
 240                 kfree(worker_name);
 241                 if (IS_ERR(ptp->kworker)) {
 242                         err = PTR_ERR(ptp->kworker);
 243                         pr_err("failed to create ptp aux_worker %d\n", err);
 244                         goto kworker_err;
 245                 }
 246         }
 247
 248         err = ptp_populate_pin_groups(ptp);
 249         if (err)
 250                 goto no_pin_groups;
 251
 252         /* Register a new PPS source. */
 253         if (info->pps) {
 254                 struct pps_source_info pps;
 255                 memset(&pps, 0, sizeof(pps));
 256                 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
 257                 pps.mode = PTP_PPS_MODE;
 258                 pps.owner = info->owner;
 259                 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
 260                 if (!ptp->pps_source) {
 261                         err = -EINVAL;
 262                         pr_err("failed to register pps source\n");
 263                         goto no_pps;
 264                 }
 265         }
 266
 267         /* Initialize a new device of our class in our clock structure. */
 268         device_initialize(&ptp->dev);
 269         ptp->dev.devt = ptp->devid;
 270         ptp->dev.class = ptp_class;
 271         ptp->dev.parent = parent;
 272         ptp->dev.groups = ptp->pin_attr_groups;
 273         ptp->dev.release = ptp_clock_release;
 274         dev_set_drvdata(&ptp->dev, ptp);
 275         dev_set_name(&ptp->dev, "ptp%d", ptp->index);
 276
 277         /* Create a posix clock and link it to the device. */
 278         err = posix_clock_register(&ptp->clock, &ptp->dev);
 279         if (err) {
 280                 pr_err("failed to create posix clock\n");
 281                 goto no_clock;
 282         }
 283
 284         return ptp;
 285
 286 no_clock:
 287         if (ptp->pps_source)
 288                 pps_unregister_source(ptp->pps_source);
 289 no_pps:
 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         posix_clock_unregister(&ptp->clock);
 320
 321         return 0;
 322 }
 323 EXPORT_SYMBOL(ptp_clock_unregister);
 324
 325 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
 326 {
 327         struct pps_event_time evt;
 328
 329         switch (event->type) {
 330
 331         case PTP_CLOCK_ALARM:
 332                 break;
 333
 334         case PTP_CLOCK_EXTTS:
 335                 enqueue_external_timestamp(&ptp->tsevq, event);
 336                 wake_up_interruptible(&ptp->tsev_wq);
 337                 break;
 338
 339         case PTP_CLOCK_PPS:
 340                 pps_get_ts(&evt);
 341                 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
 342                 break;
 343
 344         case PTP_CLOCK_PPSUSR:
 345                 pps_event(ptp->pps_source, &event->pps_times,
 346                           PTP_PPS_EVENT, NULL);
 347                 break;
 348         }
 349 }
 350 EXPORT_SYMBOL(ptp_clock_event);
 351
 352 int ptp_clock_index(struct ptp_clock *ptp)
 353 {
 354         return ptp->index;
 355 }
 356 EXPORT_SYMBOL(ptp_clock_index);
 357
 358 int ptp_find_pin(struct ptp_clock *ptp,
 359                  enum ptp_pin_function func, unsigned int chan)
 360 {
 361         struct ptp_pin_desc *pin = NULL;
 362         int i;
 363
 364         mutex_lock(&ptp->pincfg_mux);
 365         for (i = 0; i < ptp->info->n_pins; i++) {
 366                 if (ptp->info->pin_config[i].func == func &&
 367                     ptp->info->pin_config[i].chan == chan) {
 368                         pin = &ptp->info->pin_config[i];
 369                         break;
 370                 }
 371         }
 372         mutex_unlock(&ptp->pincfg_mux);
 373
 374         return pin ? i : -1;
 375 }
 376 EXPORT_SYMBOL(ptp_find_pin);
 377
 378 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
 379 {
 380         return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
 381 }
 382 EXPORT_SYMBOL(ptp_schedule_worker);
 383
 384 /* module operations */
 385
 386 static void __exit ptp_exit(void)
 387 {
 388         class_destroy(ptp_class);
 389         unregister_chrdev_region(ptp_devt, MINORMASK + 1);
 390         ida_destroy(&ptp_clocks_map);
 391 }
 392
 393 static int __init ptp_init(void)
 394 {
 395         int err;
 396
 397         ptp_class = class_create(THIS_MODULE, "ptp");
 398         if (IS_ERR(ptp_class)) {
 399                 pr_err("ptp: failed to allocate class\n");
 400                 return PTR_ERR(ptp_class);
 401         }
 402
 403         err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
 404         if (err < 0) {
 405                 pr_err("ptp: failed to allocate device region\n");
 406                 goto no_region;
 407         }
 408
 409         ptp_class->dev_groups = ptp_groups;
 410         pr_info("PTP clock support registered\n");
 411         return 0;
 412
 413 no_region:
 414         class_destroy(ptp_class);
 415         return err;
 416 }
 417
 418 subsys_initcall(ptp_init);
 419 module_exit(ptp_exit);
 420
 421 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
 422 MODULE_DESCRIPTION("PTP clocks support");
 423 MODULE_LICENSE("GPL");