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