linux/drivers/ptp/ptp_clock.c
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   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
  29static dev_t ptp_devt;
  30static struct class *ptp_class;
  31
  32static DEFINE_IDA(ptp_clocks_map);
  33
  34/* time stamp event queue operations */
  35
  36static inline int queue_free(struct timestamp_event_queue *q)
  37{
  38        return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
  39}
  40
  41static 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
  66long 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}
  85EXPORT_SYMBOL(scaled_ppm_to_ppb);
  86
  87/* posix clock implementation */
  88
  89static 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
  96static 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
 103static 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
 115static 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
 166static 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
 178static 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
 189static 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
 204struct 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
 282no_clock:
 283        if (ptp->pps_source)
 284                pps_unregister_source(ptp->pps_source);
 285no_pps:
 286        ptp_cleanup_pin_groups(ptp);
 287no_pin_groups:
 288        if (ptp->kworker)
 289                kthread_destroy_worker(ptp->kworker);
 290kworker_err:
 291        mutex_destroy(&ptp->tsevq_mux);
 292        mutex_destroy(&ptp->pincfg_mux);
 293        ida_simple_remove(&ptp_clocks_map, index);
 294no_slot:
 295        kfree(ptp);
 296no_memory:
 297        return ERR_PTR(err);
 298}
 299EXPORT_SYMBOL(ptp_clock_register);
 300
 301int 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}
 319EXPORT_SYMBOL(ptp_clock_unregister);
 320
 321void 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}
 346EXPORT_SYMBOL(ptp_clock_event);
 347
 348int ptp_clock_index(struct ptp_clock *ptp)
 349{
 350        return ptp->index;
 351}
 352EXPORT_SYMBOL(ptp_clock_index);
 353
 354int 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}
 370EXPORT_SYMBOL(ptp_find_pin);
 371
 372int 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}
 385EXPORT_SYMBOL(ptp_find_pin_unlocked);
 386
 387int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
 388{
 389        return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
 390}
 391EXPORT_SYMBOL(ptp_schedule_worker);
 392
 393void ptp_cancel_worker_sync(struct ptp_clock *ptp)
 394{
 395        kthread_cancel_delayed_work_sync(&ptp->aux_work);
 396}
 397EXPORT_SYMBOL(ptp_cancel_worker_sync);
 398
 399/* module operations */
 400
 401static 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
 408static 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
 428no_region:
 429        class_destroy(ptp_class);
 430        return err;
 431}
 432
 433subsys_initcall(ptp_init);
 434module_exit(ptp_exit);
 435
 436MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
 437MODULE_DESCRIPTION("PTP clocks support");
 438MODULE_LICENSE("GPL");
 439