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