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
  32 #include "ptp_private.h"
  33
  34 #define PTP_MAX_ALARMS 4
  35 #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
  36 #define PTP_PPS_EVENT PPS_CAPTUREASSERT
  37 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
  38
  39 /* private globals */
  40
  41 static dev_t ptp_devt;
  42 static struct class *ptp_class;
  43
  44 static DEFINE_IDA(ptp_clocks_map);
  45
  46 /* time stamp event queue operations */
  47
  48 static inline int queue_free(struct timestamp_event_queue *q)
  49 {
  50         return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
  51 }
  52
  53 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
  54                                        struct ptp_clock_event *src)
  55 {
  56         struct ptp_extts_event *dst;
  57         unsigned long flags;
  58         s64 seconds;
  59         u32 remainder;
  60
  61         seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
  62
  63         spin_lock_irqsave(&queue->lock, flags);
  64
  65         dst = &queue->buf[queue->tail];
  66         dst->index = src->index;
  67         dst->t.sec = seconds;
  68         dst->t.nsec = remainder;
  69
  70         if (!queue_free(queue))
  71                 queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
  72
  73         queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;
  74
  75         spin_unlock_irqrestore(&queue->lock, flags);
  76 }
  77
  78 static s32 scaled_ppm_to_ppb(long ppm)
  79 {
  80         /*
  81          * The 'freq' field in the 'struct timex' is in parts per
  82          * million, but with a 16 bit binary fractional field.
  83          *
  84          * We want to calculate
  85          *
  86          *    ppb = scaled_ppm * 1000 / 2^16
  87          *
  88          * which simplifies to
  89          *
  90          *    ppb = scaled_ppm * 125 / 2^13
  91          */
  92         s64 ppb = 1 + ppm;
  93         ppb *= 125;
  94         ppb >>= 13;
  95         return (s32) ppb;
  96 }
  97
  98 /* posix clock implementation */
  99
 100 static int ptp_clock_getres(struct posix_clock *pc, struct timespec *tp)
 101 {
 102         tp->tv_sec = 0;
 103         tp->tv_nsec = 1;
 104         return 0;
 105 }
 106
 107 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec *tp)
 108 {
 109         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 110         struct timespec64 ts = timespec_to_timespec64(*tp);
 111
 112         return  ptp->info->settime64(ptp->info, &ts);
 113 }
 114
 115 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec *tp)
 116 {
 117         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 118         struct timespec64 ts;
 119         int err;
 120
 121         err = ptp->info->gettime64(ptp->info, &ts);
 122         if (!err)
 123                 *tp = timespec64_to_timespec(ts);
 124         return err;
 125 }
 126
 127 static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx)
 128 {
 129         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 130         struct ptp_clock_info *ops;
 131         int err = -EOPNOTSUPP;
 132
 133         ops = ptp->info;
 134
 135         if (tx->modes & ADJ_SETOFFSET) {
 136                 struct timespec ts;
 137                 ktime_t kt;
 138                 s64 delta;
 139
 140                 ts.tv_sec  = tx->time.tv_sec;
 141                 ts.tv_nsec = tx->time.tv_usec;
 142
 143                 if (!(tx->modes & ADJ_NANO))
 144                         ts.tv_nsec *= 1000;
 145
 146                 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
 147                         return -EINVAL;
 148
 149                 kt = timespec_to_ktime(ts);
 150                 delta = ktime_to_ns(kt);
 151                 err = ops->adjtime(ops, delta);
 152         } else if (tx->modes & ADJ_FREQUENCY) {
 153                 s32 ppb = scaled_ppm_to_ppb(tx->freq);
 154                 if (ppb > ops->max_adj || ppb < -ops->max_adj)
 155                         return -ERANGE;
 156                 if (ops->adjfine)
 157                         err = ops->adjfine(ops, tx->freq);
 158                 else
 159                         err = ops->adjfreq(ops, ppb);
 160                 ptp->dialed_frequency = tx->freq;
 161         } else if (tx->modes == 0) {
 162                 tx->freq = ptp->dialed_frequency;
 163                 err = 0;
 164         }
 165
 166         return err;
 167 }
 168
 169 static struct posix_clock_operations ptp_clock_ops = {
 170         .owner          = THIS_MODULE,
 171         .clock_adjtime  = ptp_clock_adjtime,
 172         .clock_gettime  = ptp_clock_gettime,
 173         .clock_getres   = ptp_clock_getres,
 174         .clock_settime  = ptp_clock_settime,
 175         .ioctl          = ptp_ioctl,
 176         .open           = ptp_open,
 177         .poll           = ptp_poll,
 178         .read           = ptp_read,
 179 };
 180
 181 static void delete_ptp_clock(struct posix_clock *pc)
 182 {
 183         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 184
 185         mutex_destroy(&ptp->tsevq_mux);
 186         mutex_destroy(&ptp->pincfg_mux);
 187         ida_simple_remove(&ptp_clocks_map, ptp->index);
 188         kfree(ptp);
 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         err = ptp_populate_pin_groups(ptp);
 225         if (err)
 226                 goto no_pin_groups;
 227
 228         /* Create a new device in our class. */
 229         ptp->dev = device_create_with_groups(ptp_class, parent, ptp->devid,
 230                                              ptp, ptp->pin_attr_groups,
 231                                              "ptp%d", ptp->index);
 232         if (IS_ERR(ptp->dev))
 233                 goto no_device;
 234
 235         /* Register a new PPS source. */
 236         if (info->pps) {
 237                 struct pps_source_info pps;
 238                 memset(&pps, 0, sizeof(pps));
 239                 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
 240                 pps.mode = PTP_PPS_MODE;
 241                 pps.owner = info->owner;
 242                 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
 243                 if (!ptp->pps_source) {
 244                         pr_err("failed to register pps source\n");
 245                         goto no_pps;
 246                 }
 247         }
 248
 249         /* Create a posix clock. */
 250         err = posix_clock_register(&ptp->clock, ptp->devid);
 251         if (err) {
 252                 pr_err("failed to create posix clock\n");
 253                 goto no_clock;
 254         }
 255
 256         return ptp;
 257
 258 no_clock:
 259         if (ptp->pps_source)
 260                 pps_unregister_source(ptp->pps_source);
 261 no_pps:
 262         device_destroy(ptp_class, ptp->devid);
 263 no_device:
 264         ptp_cleanup_pin_groups(ptp);
 265 no_pin_groups:
 266         mutex_destroy(&ptp->tsevq_mux);
 267         mutex_destroy(&ptp->pincfg_mux);
 268         ida_simple_remove(&ptp_clocks_map, index);
 269 no_slot:
 270         kfree(ptp);
 271 no_memory:
 272         return ERR_PTR(err);
 273 }
 274 EXPORT_SYMBOL(ptp_clock_register);
 275
 276 int ptp_clock_unregister(struct ptp_clock *ptp)
 277 {
 278         ptp->defunct = 1;
 279         wake_up_interruptible(&ptp->tsev_wq);
 280
 281         /* Release the clock's resources. */
 282         if (ptp->pps_source)
 283                 pps_unregister_source(ptp->pps_source);
 284
 285         device_destroy(ptp_class, ptp->devid);
 286         ptp_cleanup_pin_groups(ptp);
 287
 288         posix_clock_unregister(&ptp->clock);
 289         return 0;
 290 }
 291 EXPORT_SYMBOL(ptp_clock_unregister);
 292
 293 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
 294 {
 295         struct pps_event_time evt;
 296
 297         switch (event->type) {
 298
 299         case PTP_CLOCK_ALARM:
 300                 break;
 301
 302         case PTP_CLOCK_EXTTS:
 303                 enqueue_external_timestamp(&ptp->tsevq, event);
 304                 wake_up_interruptible(&ptp->tsev_wq);
 305                 break;
 306
 307         case PTP_CLOCK_PPS:
 308                 pps_get_ts(&evt);
 309                 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
 310                 break;
 311
 312         case PTP_CLOCK_PPSUSR:
 313                 pps_event(ptp->pps_source, &event->pps_times,
 314                           PTP_PPS_EVENT, NULL);
 315                 break;
 316         }
 317 }
 318 EXPORT_SYMBOL(ptp_clock_event);
 319
 320 int ptp_clock_index(struct ptp_clock *ptp)
 321 {
 322         return ptp->index;
 323 }
 324 EXPORT_SYMBOL(ptp_clock_index);
 325
 326 int ptp_find_pin(struct ptp_clock *ptp,
 327                  enum ptp_pin_function func, unsigned int chan)
 328 {
 329         struct ptp_pin_desc *pin = NULL;
 330         int i;
 331
 332         mutex_lock(&ptp->pincfg_mux);
 333         for (i = 0; i < ptp->info->n_pins; i++) {
 334                 if (ptp->info->pin_config[i].func == func &&
 335                     ptp->info->pin_config[i].chan == chan) {
 336                         pin = &ptp->info->pin_config[i];
 337                         break;
 338                 }
 339         }
 340         mutex_unlock(&ptp->pincfg_mux);
 341
 342         return pin ? i : -1;
 343 }
 344 EXPORT_SYMBOL(ptp_find_pin);
 345
 346 /* module operations */
 347
 348 static void __exit ptp_exit(void)
 349 {
 350         class_destroy(ptp_class);
 351         unregister_chrdev_region(ptp_devt, MINORMASK + 1);
 352         ida_destroy(&ptp_clocks_map);
 353 }
 354
 355 static int __init ptp_init(void)
 356 {
 357         int err;
 358
 359         ptp_class = class_create(THIS_MODULE, "ptp");
 360         if (IS_ERR(ptp_class)) {
 361                 pr_err("ptp: failed to allocate class\n");
 362                 return PTR_ERR(ptp_class);
 363         }
 364
 365         err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
 366         if (err < 0) {
 367                 pr_err("ptp: failed to allocate device region\n");
 368                 goto no_region;
 369         }
 370
 371         ptp_class->dev_groups = ptp_groups;
 372         pr_info("PTP clock support registered\n");
 373         return 0;
 374
 375 no_region:
 376         class_destroy(ptp_class);
 377         return err;
 378 }
 379
 380 subsys_initcall(ptp_init);
 381 module_exit(ptp_exit);
 382
 383 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
 384 MODULE_DESCRIPTION("PTP clocks support");
 385 MODULE_LICENSE("GPL");