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 ptp_clock_release(struct device *dev) 170 { 171 struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev); 172 173 ptp_cleanup_pin_groups(ptp); 174 mutex_destroy(&ptp->tsevq_mux); 175 mutex_destroy(&ptp->pincfg_mux); 176 ida_simple_remove(&ptp_clocks_map, ptp->index); 177 kfree(ptp); 178 } 179 180 static void ptp_aux_kworker(struct kthread_work *work) 181 { 182 struct ptp_clock *ptp = container_of(work, struct ptp_clock, 183 aux_work.work); 184 struct ptp_clock_info *info = ptp->info; 185 long delay; 186 187 delay = info->do_aux_work(info); 188 189 if (delay >= 0) 190 kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay); 191 } 192 193 /* public interface */ 194 195 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info, 196 struct device *parent) 197 { 198 struct ptp_clock *ptp; 199 int err = 0, index, major = MAJOR(ptp_devt); 200 201 if (info->n_alarm > PTP_MAX_ALARMS) 202 return ERR_PTR(-EINVAL); 203 204 /* Initialize a clock structure. */ 205 err = -ENOMEM; 206 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL); 207 if (ptp == NULL) 208 goto no_memory; 209 210 index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL); 211 if (index < 0) { 212 err = index; 213 goto no_slot; 214 } 215 216 ptp->clock.ops = ptp_clock_ops; 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 /* Register a new PPS source. */ 240 if (info->pps) { 241 struct pps_source_info pps; 242 memset(&pps, 0, sizeof(pps)); 243 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index); 244 pps.mode = PTP_PPS_MODE; 245 pps.owner = info->owner; 246 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS); 247 if (IS_ERR(ptp->pps_source)) { 248 err = PTR_ERR(ptp->pps_source); 249 pr_err("failed to register pps source\n"); 250 goto no_pps; 251 } 252 } 253 254 /* Initialize a new device of our class in our clock structure. */ 255 device_initialize(&ptp->dev); 256 ptp->dev.devt = ptp->devid; 257 ptp->dev.class = ptp_class; 258 ptp->dev.parent = parent; 259 ptp->dev.groups = ptp->pin_attr_groups; 260 ptp->dev.release = ptp_clock_release; 261 dev_set_drvdata(&ptp->dev, ptp); 262 dev_set_name(&ptp->dev, "ptp%d", ptp->index); 263 264 /* Create a posix clock and link it to the device. */ 265 err = posix_clock_register(&ptp->clock, &ptp->dev); 266 if (err) { 267 pr_err("failed to create posix clock\n"); 268 goto no_clock; 269 } 270 271 return ptp; 272 273 no_clock: 274 if (ptp->pps_source) 275 pps_unregister_source(ptp->pps_source); 276 no_pps: 277 ptp_cleanup_pin_groups(ptp); 278 no_pin_groups: 279 if (ptp->kworker) 280 kthread_destroy_worker(ptp->kworker); 281 kworker_err: 282 mutex_destroy(&ptp->tsevq_mux); 283 mutex_destroy(&ptp->pincfg_mux); 284 ida_simple_remove(&ptp_clocks_map, index); 285 no_slot: 286 kfree(ptp); 287 no_memory: 288 return ERR_PTR(err); 289 } 290 EXPORT_SYMBOL(ptp_clock_register); 291 292 int ptp_clock_unregister(struct ptp_clock *ptp) 293 { 294 ptp->defunct = 1; 295 wake_up_interruptible(&ptp->tsev_wq); 296 297 if (ptp->kworker) { 298 kthread_cancel_delayed_work_sync(&ptp->aux_work); 299 kthread_destroy_worker(ptp->kworker); 300 } 301 302 /* Release the clock's resources. */ 303 if (ptp->pps_source) 304 pps_unregister_source(ptp->pps_source); 305 306 posix_clock_unregister(&ptp->clock); 307 308 return 0; 309 } 310 EXPORT_SYMBOL(ptp_clock_unregister); 311 312 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event) 313 { 314 struct pps_event_time evt; 315 316 switch (event->type) { 317 318 case PTP_CLOCK_ALARM: 319 break; 320 321 case PTP_CLOCK_EXTTS: 322 enqueue_external_timestamp(&ptp->tsevq, event); 323 wake_up_interruptible(&ptp->tsev_wq); 324 break; 325 326 case PTP_CLOCK_PPS: 327 pps_get_ts(&evt); 328 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL); 329 break; 330 331 case PTP_CLOCK_PPSUSR: 332 pps_event(ptp->pps_source, &event->pps_times, 333 PTP_PPS_EVENT, NULL); 334 break; 335 } 336 } 337 EXPORT_SYMBOL(ptp_clock_event); 338 339 int ptp_clock_index(struct ptp_clock *ptp) 340 { 341 return ptp->index; 342 } 343 EXPORT_SYMBOL(ptp_clock_index); 344 345 int ptp_find_pin(struct ptp_clock *ptp, 346 enum ptp_pin_function func, unsigned int chan) 347 { 348 struct ptp_pin_desc *pin = NULL; 349 int i; 350 351 mutex_lock(&ptp->pincfg_mux); 352 for (i = 0; i < ptp->info->n_pins; i++) { 353 if (ptp->info->pin_config[i].func == func && 354 ptp->info->pin_config[i].chan == chan) { 355 pin = &ptp->info->pin_config[i]; 356 break; 357 } 358 } 359 mutex_unlock(&ptp->pincfg_mux); 360 361 return pin ? i : -1; 362 } 363 EXPORT_SYMBOL(ptp_find_pin); 364 365 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay) 366 { 367 return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay); 368 } 369 EXPORT_SYMBOL(ptp_schedule_worker); 370 371 /* module operations */ 372 373 static void __exit ptp_exit(void) 374 { 375 class_destroy(ptp_class); 376 unregister_chrdev_region(ptp_devt, MINORMASK + 1); 377 ida_destroy(&ptp_clocks_map); 378 } 379 380 static int __init ptp_init(void) 381 { 382 int err; 383 384 ptp_class = class_create(THIS_MODULE, "ptp"); 385 if (IS_ERR(ptp_class)) { 386 pr_err("ptp: failed to allocate class\n"); 387 return PTR_ERR(ptp_class); 388 } 389 390 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp"); 391 if (err < 0) { 392 pr_err("ptp: failed to allocate device region\n"); 393 goto no_region; 394 } 395 396 ptp_class->dev_groups = ptp_groups; 397 pr_info("PTP clock support registered\n"); 398 return 0; 399 400 no_region: 401 class_destroy(ptp_class); 402 return err; 403 } 404 405 subsys_initcall(ptp_init); 406 module_exit(ptp_exit); 407 408 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>"); 409 MODULE_DESCRIPTION("PTP clocks support"); 410 MODULE_LICENSE("GPL"); 411