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 #include <uapi/linux/sched/types.h> 32 33 #include "ptp_private.h" 34 35 #define PTP_MAX_ALARMS 4 36 #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT) 37 #define PTP_PPS_EVENT PPS_CAPTUREASSERT 38 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC) 39 40 /* private globals */ 41 42 static dev_t ptp_devt; 43 static struct class *ptp_class; 44 45 static DEFINE_IDA(ptp_clocks_map); 46 47 /* time stamp event queue operations */ 48 49 static inline int queue_free(struct timestamp_event_queue *q) 50 { 51 return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1; 52 } 53 54 static void enqueue_external_timestamp(struct timestamp_event_queue *queue, 55 struct ptp_clock_event *src) 56 { 57 struct ptp_extts_event *dst; 58 unsigned long flags; 59 s64 seconds; 60 u32 remainder; 61 62 seconds = div_u64_rem(src->timestamp, 1000000000, &remainder); 63 64 spin_lock_irqsave(&queue->lock, flags); 65 66 dst = &queue->buf[queue->tail]; 67 dst->index = src->index; 68 dst->t.sec = seconds; 69 dst->t.nsec = remainder; 70 71 if (!queue_free(queue)) 72 queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS; 73 74 queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS; 75 76 spin_unlock_irqrestore(&queue->lock, flags); 77 } 78 79 static s32 scaled_ppm_to_ppb(long ppm) 80 { 81 /* 82 * The 'freq' field in the 'struct timex' is in parts per 83 * million, but with a 16 bit binary fractional field. 84 * 85 * We want to calculate 86 * 87 * ppb = scaled_ppm * 1000 / 2^16 88 * 89 * which simplifies to 90 * 91 * ppb = scaled_ppm * 125 / 2^13 92 */ 93 s64 ppb = 1 + ppm; 94 ppb *= 125; 95 ppb >>= 13; 96 return (s32) ppb; 97 } 98 99 /* posix clock implementation */ 100 101 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp) 102 { 103 tp->tv_sec = 0; 104 tp->tv_nsec = 1; 105 return 0; 106 } 107 108 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp) 109 { 110 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 111 112 return ptp->info->settime64(ptp->info, tp); 113 } 114 115 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp) 116 { 117 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 118 int err; 119 120 err = ptp->info->gettime64(ptp->info, tp); 121 return err; 122 } 123 124 static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx) 125 { 126 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 127 struct ptp_clock_info *ops; 128 int err = -EOPNOTSUPP; 129 130 ops = ptp->info; 131 132 if (tx->modes & ADJ_SETOFFSET) { 133 struct timespec64 ts; 134 ktime_t kt; 135 s64 delta; 136 137 ts.tv_sec = tx->time.tv_sec; 138 ts.tv_nsec = tx->time.tv_usec; 139 140 if (!(tx->modes & ADJ_NANO)) 141 ts.tv_nsec *= 1000; 142 143 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC) 144 return -EINVAL; 145 146 kt = timespec64_to_ktime(ts); 147 delta = ktime_to_ns(kt); 148 err = ops->adjtime(ops, delta); 149 } else if (tx->modes & ADJ_FREQUENCY) { 150 s32 ppb = scaled_ppm_to_ppb(tx->freq); 151 if (ppb > ops->max_adj || ppb < -ops->max_adj) 152 return -ERANGE; 153 if (ops->adjfine) 154 err = ops->adjfine(ops, tx->freq); 155 else 156 err = ops->adjfreq(ops, ppb); 157 ptp->dialed_frequency = tx->freq; 158 } else if (tx->modes == 0) { 159 tx->freq = ptp->dialed_frequency; 160 err = 0; 161 } 162 163 return err; 164 } 165 166 static 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 }; 177 178 static void delete_ptp_clock(struct posix_clock *pc) 179 { 180 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 181 182 mutex_destroy(&ptp->tsevq_mux); 183 mutex_destroy(&ptp->pincfg_mux); 184 ida_simple_remove(&ptp_clocks_map, ptp->index); 185 kfree(ptp); 186 } 187 188 static void ptp_aux_kworker(struct kthread_work *work) 189 { 190 struct ptp_clock *ptp = container_of(work, struct ptp_clock, 191 aux_work.work); 192 struct ptp_clock_info *info = ptp->info; 193 long delay; 194 195 delay = info->do_aux_work(info); 196 197 if (delay >= 0) 198 kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay); 199 } 200 201 /* public interface */ 202 203 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info, 204 struct device *parent) 205 { 206 struct ptp_clock *ptp; 207 int err = 0, index, major = MAJOR(ptp_devt); 208 209 if (info->n_alarm > PTP_MAX_ALARMS) 210 return ERR_PTR(-EINVAL); 211 212 /* Initialize a clock structure. */ 213 err = -ENOMEM; 214 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL); 215 if (ptp == NULL) 216 goto no_memory; 217 218 index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL); 219 if (index < 0) { 220 err = index; 221 goto no_slot; 222 } 223 224 ptp->clock.ops = ptp_clock_ops; 225 ptp->clock.release = delete_ptp_clock; 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 /* Create a new device in our class. */ 249 ptp->dev = device_create_with_groups(ptp_class, parent, ptp->devid, 250 ptp, ptp->pin_attr_groups, 251 "ptp%d", ptp->index); 252 if (IS_ERR(ptp->dev)) 253 goto no_device; 254 255 /* Register a new PPS source. */ 256 if (info->pps) { 257 struct pps_source_info pps; 258 memset(&pps, 0, sizeof(pps)); 259 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index); 260 pps.mode = PTP_PPS_MODE; 261 pps.owner = info->owner; 262 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS); 263 if (!ptp->pps_source) { 264 pr_err("failed to register pps source\n"); 265 goto no_pps; 266 } 267 } 268 269 /* Create a posix clock. */ 270 err = posix_clock_register(&ptp->clock, ptp->devid); 271 if (err) { 272 pr_err("failed to create posix clock\n"); 273 goto no_clock; 274 } 275 276 return ptp; 277 278 no_clock: 279 if (ptp->pps_source) 280 pps_unregister_source(ptp->pps_source); 281 no_pps: 282 device_destroy(ptp_class, ptp->devid); 283 no_device: 284 ptp_cleanup_pin_groups(ptp); 285 no_pin_groups: 286 if (ptp->kworker) 287 kthread_destroy_worker(ptp->kworker); 288 kworker_err: 289 mutex_destroy(&ptp->tsevq_mux); 290 mutex_destroy(&ptp->pincfg_mux); 291 ida_simple_remove(&ptp_clocks_map, index); 292 no_slot: 293 kfree(ptp); 294 no_memory: 295 return ERR_PTR(err); 296 } 297 EXPORT_SYMBOL(ptp_clock_register); 298 299 int ptp_clock_unregister(struct ptp_clock *ptp) 300 { 301 ptp->defunct = 1; 302 wake_up_interruptible(&ptp->tsev_wq); 303 304 if (ptp->kworker) { 305 kthread_cancel_delayed_work_sync(&ptp->aux_work); 306 kthread_destroy_worker(ptp->kworker); 307 } 308 309 /* Release the clock's resources. */ 310 if (ptp->pps_source) 311 pps_unregister_source(ptp->pps_source); 312 313 device_destroy(ptp_class, ptp->devid); 314 ptp_cleanup_pin_groups(ptp); 315 316 posix_clock_unregister(&ptp->clock); 317 return 0; 318 } 319 EXPORT_SYMBOL(ptp_clock_unregister); 320 321 void 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 } 346 EXPORT_SYMBOL(ptp_clock_event); 347 348 int ptp_clock_index(struct ptp_clock *ptp) 349 { 350 return ptp->index; 351 } 352 EXPORT_SYMBOL(ptp_clock_index); 353 354 int 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 mutex_lock(&ptp->pincfg_mux); 361 for (i = 0; i < ptp->info->n_pins; i++) { 362 if (ptp->info->pin_config[i].func == func && 363 ptp->info->pin_config[i].chan == chan) { 364 pin = &ptp->info->pin_config[i]; 365 break; 366 } 367 } 368 mutex_unlock(&ptp->pincfg_mux); 369 370 return pin ? i : -1; 371 } 372 EXPORT_SYMBOL(ptp_find_pin); 373 374 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay) 375 { 376 return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay); 377 } 378 EXPORT_SYMBOL(ptp_schedule_worker); 379 380 /* module operations */ 381 382 static void __exit ptp_exit(void) 383 { 384 class_destroy(ptp_class); 385 unregister_chrdev_region(ptp_devt, MINORMASK + 1); 386 ida_destroy(&ptp_clocks_map); 387 } 388 389 static int __init ptp_init(void) 390 { 391 int err; 392 393 ptp_class = class_create(THIS_MODULE, "ptp"); 394 if (IS_ERR(ptp_class)) { 395 pr_err("ptp: failed to allocate class\n"); 396 return PTR_ERR(ptp_class); 397 } 398 399 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp"); 400 if (err < 0) { 401 pr_err("ptp: failed to allocate device region\n"); 402 goto no_region; 403 } 404 405 ptp_class->dev_groups = ptp_groups; 406 pr_info("PTP clock support registered\n"); 407 return 0; 408 409 no_region: 410 class_destroy(ptp_class); 411 return err; 412 } 413 414 subsys_initcall(ptp_init); 415 module_exit(ptp_exit); 416 417 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>"); 418 MODULE_DESCRIPTION("PTP clocks support"); 419 MODULE_LICENSE("GPL"); 420