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