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 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 EXPORT_SYMBOL(scaled_ppm_to_ppb);
  86
  87 /* posix clock implementation */
  88
  89 static 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
  96 static 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
 103 static 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
 115 static 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                 s32 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 == 0) {
 150                 tx->freq = ptp->dialed_frequency;
 151                 err = 0;
 152         }
 153
 154         return err;
 155 }
 156
 157 static struct posix_clock_operations ptp_clock_ops = {
 158         .owner          = THIS_MODULE,
 159         .clock_adjtime  = ptp_clock_adjtime,
 160         .clock_gettime  = ptp_clock_gettime,
 161         .clock_getres   = ptp_clock_getres,
 162         .clock_settime  = ptp_clock_settime,
 163         .ioctl          = ptp_ioctl,
 164         .open           = ptp_open,
 165         .poll           = ptp_poll,
 166         .read           = ptp_read,
 167 };
 168
 169 static void delete_ptp_clock(struct posix_clock *pc)
 170 {
 171         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 172
 173         mutex_destroy(&ptp->tsevq_mux);
 174         mutex_destroy(&ptp->pincfg_mux);
 175         ida_simple_remove(&ptp_clocks_map, ptp->index);
 176         kfree(ptp);
 177 }
 178
 179 static void ptp_aux_kworker(struct kthread_work *work)
 180 {
 181         struct ptp_clock *ptp = container_of(work, struct ptp_clock,
 182                                              aux_work.work);
 183         struct ptp_clock_info *info = ptp->info;
 184         long delay;
 185
 186         delay = info->do_aux_work(info);
 187
 188         if (delay >= 0)
 189                 kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
 190 }
 191
 192 /* public interface */
 193
 194 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 195                                      struct device *parent)
 196 {
 197         struct ptp_clock *ptp;
 198         int err = 0, index, major = MAJOR(ptp_devt);
 199
 200         if (info->n_alarm > PTP_MAX_ALARMS)
 201                 return ERR_PTR(-EINVAL);
 202
 203         /* Initialize a clock structure. */
 204         err = -ENOMEM;
 205         ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
 206         if (ptp == NULL)
 207                 goto no_memory;
 208
 209         index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
 210         if (index < 0) {
 211                 err = index;
 212                 goto no_slot;
 213         }
 214
 215         ptp->clock.ops = ptp_clock_ops;
 216         ptp->clock.release = delete_ptp_clock;
 217         ptp->info = info;
 218         ptp->devid = MKDEV(major, index);
 219         ptp->index = index;
 220         spin_lock_init(&ptp->tsevq.lock);
 221         mutex_init(&ptp->tsevq_mux);
 222         mutex_init(&ptp->pincfg_mux);
 223         init_waitqueue_head(&ptp->tsev_wq);
 224
 225         if (ptp->info->do_aux_work) {
 226                 kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
 227                 ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
 228                 if (IS_ERR(ptp->kworker)) {
 229                         err = PTR_ERR(ptp->kworker);
 230                         pr_err("failed to create ptp aux_worker %d\n", err);
 231                         goto kworker_err;
 232                 }
 233         }
 234
 235         err = ptp_populate_pin_groups(ptp);
 236         if (err)
 237                 goto no_pin_groups;
 238
 239         /* Create a new device in our class. */
 240         ptp->dev = device_create_with_groups(ptp_class, parent, ptp->devid,
 241                                              ptp, ptp->pin_attr_groups,
 242                                              "ptp%d", ptp->index);
 243         if (IS_ERR(ptp->dev)) {
 244                 err = PTR_ERR(ptp->dev);
 245                 goto no_device;
 246         }
 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         /* Create a posix clock. */
 264         err = posix_clock_register(&ptp->clock, ptp->devid);
 265         if (err) {
 266                 pr_err("failed to create posix clock\n");
 267                 goto no_clock;
 268         }
 269
 270         return ptp;
 271
 272 no_clock:
 273         if (ptp->pps_source)
 274                 pps_unregister_source(ptp->pps_source);
 275 no_pps:
 276         device_destroy(ptp_class, ptp->devid);
 277 no_device:
 278         ptp_cleanup_pin_groups(ptp);
 279 no_pin_groups:
 280         if (ptp->kworker)
 281                 kthread_destroy_worker(ptp->kworker);
 282 kworker_err:
 283         mutex_destroy(&ptp->tsevq_mux);
 284         mutex_destroy(&ptp->pincfg_mux);
 285         ida_simple_remove(&ptp_clocks_map, index);
 286 no_slot:
 287         kfree(ptp);
 288 no_memory:
 289         return ERR_PTR(err);
 290 }
 291 EXPORT_SYMBOL(ptp_clock_register);
 292
 293 int ptp_clock_unregister(struct ptp_clock *ptp)
 294 {
 295         ptp->defunct = 1;
 296         wake_up_interruptible(&ptp->tsev_wq);
 297
 298         if (ptp->kworker) {
 299                 kthread_cancel_delayed_work_sync(&ptp->aux_work);
 300                 kthread_destroy_worker(ptp->kworker);
 301         }
 302
 303         /* Release the clock's resources. */
 304         if (ptp->pps_source)
 305                 pps_unregister_source(ptp->pps_source);
 306
 307         device_destroy(ptp_class, ptp->devid);
 308         ptp_cleanup_pin_groups(ptp);
 309
 310         posix_clock_unregister(&ptp->clock);
 311         return 0;
 312 }
 313 EXPORT_SYMBOL(ptp_clock_unregister);
 314
 315 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
 316 {
 317         struct pps_event_time evt;
 318
 319         switch (event->type) {
 320
 321         case PTP_CLOCK_ALARM:
 322                 break;
 323
 324         case PTP_CLOCK_EXTTS:
 325                 enqueue_external_timestamp(&ptp->tsevq, event);
 326                 wake_up_interruptible(&ptp->tsev_wq);
 327                 break;
 328
 329         case PTP_CLOCK_PPS:
 330                 pps_get_ts(&evt);
 331                 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
 332                 break;
 333
 334         case PTP_CLOCK_PPSUSR:
 335                 pps_event(ptp->pps_source, &event->pps_times,
 336                           PTP_PPS_EVENT, NULL);
 337                 break;
 338         }
 339 }
 340 EXPORT_SYMBOL(ptp_clock_event);
 341
 342 int ptp_clock_index(struct ptp_clock *ptp)
 343 {
 344         return ptp->index;
 345 }
 346 EXPORT_SYMBOL(ptp_clock_index);
 347
 348 int ptp_find_pin(struct ptp_clock *ptp,
 349                  enum ptp_pin_function func, unsigned int chan)
 350 {
 351         struct ptp_pin_desc *pin = NULL;
 352         int i;
 353
 354         mutex_lock(&ptp->pincfg_mux);
 355         for (i = 0; i < ptp->info->n_pins; i++) {
 356                 if (ptp->info->pin_config[i].func == func &&
 357                     ptp->info->pin_config[i].chan == chan) {
 358                         pin = &ptp->info->pin_config[i];
 359                         break;
 360                 }
 361         }
 362         mutex_unlock(&ptp->pincfg_mux);
 363
 364         return pin ? i : -1;
 365 }
 366 EXPORT_SYMBOL(ptp_find_pin);
 367
 368 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
 369 {
 370         return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
 371 }
 372 EXPORT_SYMBOL(ptp_schedule_worker);
 373
 374 /* module operations */
 375
 376 static void __exit ptp_exit(void)
 377 {
 378         class_destroy(ptp_class);
 379         unregister_chrdev_region(ptp_devt, MINORMASK + 1);
 380         ida_destroy(&ptp_clocks_map);
 381 }
 382
 383 static int __init ptp_init(void)
 384 {
 385         int err;
 386
 387         ptp_class = class_create(THIS_MODULE, "ptp");
 388         if (IS_ERR(ptp_class)) {
 389                 pr_err("ptp: failed to allocate class\n");
 390                 return PTR_ERR(ptp_class);
 391         }
 392
 393         err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
 394         if (err < 0) {
 395                 pr_err("ptp: failed to allocate device region\n");
 396                 goto no_region;
 397         }
 398
 399         ptp_class->dev_groups = ptp_groups;
 400         pr_info("PTP clock support registered\n");
 401         return 0;
 402
 403 no_region:
 404         class_destroy(ptp_class);
 405         return err;
 406 }
 407
 408 subsys_initcall(ptp_init);
 409 module_exit(ptp_exit);
 410
 411 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
 412 MODULE_DESCRIPTION("PTP clocks support");
 413 MODULE_LICENSE("GPL");