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"); 414