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 if (ptp->info->gettimex64) 121 err = ptp->info->gettimex64(ptp->info, tp, NULL); 122 else 123 err = ptp->info->gettime64(ptp->info, tp); 124 return err; 125 } 126 127 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_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 timespec64 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 = timespec64_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 static void ptp_aux_kworker(struct kthread_work *work) 192 { 193 struct ptp_clock *ptp = container_of(work, struct ptp_clock, 194 aux_work.work); 195 struct ptp_clock_info *info = ptp->info; 196 long delay; 197 198 delay = info->do_aux_work(info); 199 200 if (delay >= 0) 201 kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay); 202 } 203 204 /* public interface */ 205 206 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info, 207 struct device *parent) 208 { 209 struct ptp_clock *ptp; 210 int err = 0, index, major = MAJOR(ptp_devt); 211 212 if (info->n_alarm > PTP_MAX_ALARMS) 213 return ERR_PTR(-EINVAL); 214 215 /* Initialize a clock structure. */ 216 err = -ENOMEM; 217 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL); 218 if (ptp == NULL) 219 goto no_memory; 220 221 index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL); 222 if (index < 0) { 223 err = index; 224 goto no_slot; 225 } 226 227 ptp->clock.ops = ptp_clock_ops; 228 ptp->clock.release = delete_ptp_clock; 229 ptp->info = info; 230 ptp->devid = MKDEV(major, index); 231 ptp->index = index; 232 spin_lock_init(&ptp->tsevq.lock); 233 mutex_init(&ptp->tsevq_mux); 234 mutex_init(&ptp->pincfg_mux); 235 init_waitqueue_head(&ptp->tsev_wq); 236 237 if (ptp->info->do_aux_work) { 238 kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker); 239 ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index); 240 if (IS_ERR(ptp->kworker)) { 241 err = PTR_ERR(ptp->kworker); 242 pr_err("failed to create ptp aux_worker %d\n", err); 243 goto kworker_err; 244 } 245 } 246 247 err = ptp_populate_pin_groups(ptp); 248 if (err) 249 goto no_pin_groups; 250 251 /* Create a new device in our class. */ 252 ptp->dev = device_create_with_groups(ptp_class, parent, ptp->devid, 253 ptp, ptp->pin_attr_groups, 254 "ptp%d", ptp->index); 255 if (IS_ERR(ptp->dev)) { 256 err = PTR_ERR(ptp->dev); 257 goto no_device; 258 } 259 260 /* Register a new PPS source. */ 261 if (info->pps) { 262 struct pps_source_info pps; 263 memset(&pps, 0, sizeof(pps)); 264 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index); 265 pps.mode = PTP_PPS_MODE; 266 pps.owner = info->owner; 267 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS); 268 if (IS_ERR(ptp->pps_source)) { 269 err = PTR_ERR(ptp->pps_source); 270 pr_err("failed to register pps source\n"); 271 goto no_pps; 272 } 273 } 274 275 /* Create a posix clock. */ 276 err = posix_clock_register(&ptp->clock, ptp->devid); 277 if (err) { 278 pr_err("failed to create posix clock\n"); 279 goto no_clock; 280 } 281 282 return ptp; 283 284 no_clock: 285 if (ptp->pps_source) 286 pps_unregister_source(ptp->pps_source); 287 no_pps: 288 device_destroy(ptp_class, ptp->devid); 289 no_device: 290 ptp_cleanup_pin_groups(ptp); 291 no_pin_groups: 292 if (ptp->kworker) 293 kthread_destroy_worker(ptp->kworker); 294 kworker_err: 295 mutex_destroy(&ptp->tsevq_mux); 296 mutex_destroy(&ptp->pincfg_mux); 297 ida_simple_remove(&ptp_clocks_map, index); 298 no_slot: 299 kfree(ptp); 300 no_memory: 301 return ERR_PTR(err); 302 } 303 EXPORT_SYMBOL(ptp_clock_register); 304 305 int ptp_clock_unregister(struct ptp_clock *ptp) 306 { 307 ptp->defunct = 1; 308 wake_up_interruptible(&ptp->tsev_wq); 309 310 if (ptp->kworker) { 311 kthread_cancel_delayed_work_sync(&ptp->aux_work); 312 kthread_destroy_worker(ptp->kworker); 313 } 314 315 /* Release the clock's resources. */ 316 if (ptp->pps_source) 317 pps_unregister_source(ptp->pps_source); 318 319 device_destroy(ptp_class, ptp->devid); 320 ptp_cleanup_pin_groups(ptp); 321 322 posix_clock_unregister(&ptp->clock); 323 return 0; 324 } 325 EXPORT_SYMBOL(ptp_clock_unregister); 326 327 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event) 328 { 329 struct pps_event_time evt; 330 331 switch (event->type) { 332 333 case PTP_CLOCK_ALARM: 334 break; 335 336 case PTP_CLOCK_EXTTS: 337 enqueue_external_timestamp(&ptp->tsevq, event); 338 wake_up_interruptible(&ptp->tsev_wq); 339 break; 340 341 case PTP_CLOCK_PPS: 342 pps_get_ts(&evt); 343 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL); 344 break; 345 346 case PTP_CLOCK_PPSUSR: 347 pps_event(ptp->pps_source, &event->pps_times, 348 PTP_PPS_EVENT, NULL); 349 break; 350 } 351 } 352 EXPORT_SYMBOL(ptp_clock_event); 353 354 int ptp_clock_index(struct ptp_clock *ptp) 355 { 356 return ptp->index; 357 } 358 EXPORT_SYMBOL(ptp_clock_index); 359 360 int ptp_find_pin(struct ptp_clock *ptp, 361 enum ptp_pin_function func, unsigned int chan) 362 { 363 struct ptp_pin_desc *pin = NULL; 364 int i; 365 366 mutex_lock(&ptp->pincfg_mux); 367 for (i = 0; i < ptp->info->n_pins; i++) { 368 if (ptp->info->pin_config[i].func == func && 369 ptp->info->pin_config[i].chan == chan) { 370 pin = &ptp->info->pin_config[i]; 371 break; 372 } 373 } 374 mutex_unlock(&ptp->pincfg_mux); 375 376 return pin ? i : -1; 377 } 378 EXPORT_SYMBOL(ptp_find_pin); 379 380 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay) 381 { 382 return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay); 383 } 384 EXPORT_SYMBOL(ptp_schedule_worker); 385 386 /* module operations */ 387 388 static void __exit ptp_exit(void) 389 { 390 class_destroy(ptp_class); 391 unregister_chrdev_region(ptp_devt, MINORMASK + 1); 392 ida_destroy(&ptp_clocks_map); 393 } 394 395 static int __init ptp_init(void) 396 { 397 int err; 398 399 ptp_class = class_create(THIS_MODULE, "ptp"); 400 if (IS_ERR(ptp_class)) { 401 pr_err("ptp: failed to allocate class\n"); 402 return PTR_ERR(ptp_class); 403 } 404 405 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp"); 406 if (err < 0) { 407 pr_err("ptp: failed to allocate device region\n"); 408 goto no_region; 409 } 410 411 ptp_class->dev_groups = ptp_groups; 412 pr_info("PTP clock support registered\n"); 413 return 0; 414 415 no_region: 416 class_destroy(ptp_class); 417 return err; 418 } 419 420 subsys_initcall(ptp_init); 421 module_exit(ptp_exit); 422 423 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>"); 424 MODULE_DESCRIPTION("PTP clocks support"); 425 MODULE_LICENSE("GPL"); 426