2 * PTP 1588 clock support
4 * Copyright (C) 2010 OMICRON electronics GmbH
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.
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.
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.
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>
33 #include "ptp_private.h"
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)
42 static dev_t ptp_devt;
43 static struct class *ptp_class;
45 static DEFINE_IDA(ptp_clocks_map);
47 /* time stamp event queue operations */
49 static inline int queue_free(struct timestamp_event_queue *q)
51 return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
54 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
55 struct ptp_clock_event *src)
57 struct ptp_extts_event *dst;
62 seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
64 spin_lock_irqsave(&queue->lock, flags);
66 dst = &queue->buf[queue->tail];
67 dst->index = src->index;
69 dst->t.nsec = remainder;
71 /* Both WRITE_ONCE() are paired with READ_ONCE() in queue_cnt() */
72 if (!queue_free(queue))
73 WRITE_ONCE(queue->head, (queue->head + 1) % PTP_MAX_TIMESTAMPS);
75 WRITE_ONCE(queue->tail, (queue->tail + 1) % PTP_MAX_TIMESTAMPS);
77 spin_unlock_irqrestore(&queue->lock, flags);
80 long scaled_ppm_to_ppb(long ppm)
83 * The 'freq' field in the 'struct timex' is in parts per
84 * million, but with a 16 bit binary fractional field.
86 * We want to calculate
88 * ppb = scaled_ppm * 1000 / 2^16
92 * ppb = scaled_ppm * 125 / 2^13
99 EXPORT_SYMBOL(scaled_ppm_to_ppb);
101 /* posix clock implementation */
103 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
110 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
112 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
114 return ptp->info->settime64(ptp->info, tp);
117 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
119 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
122 err = ptp->info->gettime64(ptp->info, tp);
126 static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx)
128 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
129 struct ptp_clock_info *ops;
130 int err = -EOPNOTSUPP;
134 if (tx->modes & ADJ_SETOFFSET) {
135 struct timespec64 ts;
139 ts.tv_sec = tx->time.tv_sec;
140 ts.tv_nsec = tx->time.tv_usec;
142 if (!(tx->modes & ADJ_NANO))
145 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
148 kt = timespec64_to_ktime(ts);
149 delta = ktime_to_ns(kt);
150 err = ops->adjtime(ops, delta);
151 } else if (tx->modes & ADJ_FREQUENCY) {
152 long ppb = scaled_ppm_to_ppb(tx->freq);
153 if (ppb > ops->max_adj || ppb < -ops->max_adj)
156 err = ops->adjfine(ops, tx->freq);
158 err = ops->adjfreq(ops, ppb);
159 ptp->dialed_frequency = tx->freq;
160 } else if (tx->modes == 0) {
161 tx->freq = ptp->dialed_frequency;
168 static struct posix_clock_operations ptp_clock_ops = {
169 .owner = THIS_MODULE,
170 .clock_adjtime = ptp_clock_adjtime,
171 .clock_gettime = ptp_clock_gettime,
172 .clock_getres = ptp_clock_getres,
173 .clock_settime = ptp_clock_settime,
180 static void ptp_clock_release(struct device *dev)
182 struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
184 ptp_cleanup_pin_groups(ptp);
185 mutex_destroy(&ptp->tsevq_mux);
186 mutex_destroy(&ptp->pincfg_mux);
187 ida_simple_remove(&ptp_clocks_map, ptp->index);
191 static void ptp_aux_kworker(struct kthread_work *work)
193 struct ptp_clock *ptp = container_of(work, struct ptp_clock,
195 struct ptp_clock_info *info = ptp->info;
198 delay = info->do_aux_work(info);
201 kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
204 /* public interface */
206 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
207 struct device *parent)
209 struct ptp_clock *ptp;
210 int err = 0, index, major = MAJOR(ptp_devt);
212 if (info->n_alarm > PTP_MAX_ALARMS)
213 return ERR_PTR(-EINVAL);
215 /* Initialize a clock structure. */
217 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
221 index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
227 ptp->clock.ops = ptp_clock_ops;
229 ptp->devid = MKDEV(major, index);
231 spin_lock_init(&ptp->tsevq.lock);
232 mutex_init(&ptp->tsevq_mux);
233 mutex_init(&ptp->pincfg_mux);
234 init_waitqueue_head(&ptp->tsev_wq);
236 if (ptp->info->do_aux_work) {
237 char *worker_name = kasprintf(GFP_KERNEL, "ptp%d", ptp->index);
239 kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
240 ptp->kworker = kthread_create_worker(0, worker_name ?
241 worker_name : info->name);
243 if (IS_ERR(ptp->kworker)) {
244 err = PTR_ERR(ptp->kworker);
245 pr_err("failed to create ptp aux_worker %d\n", err);
250 err = ptp_populate_pin_groups(ptp);
254 /* Register a new PPS source. */
256 struct pps_source_info pps;
257 memset(&pps, 0, sizeof(pps));
258 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
259 pps.mode = PTP_PPS_MODE;
260 pps.owner = info->owner;
261 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
262 if (!ptp->pps_source) {
264 pr_err("failed to register pps source\n");
269 /* Initialize a new device of our class in our clock structure. */
270 device_initialize(&ptp->dev);
271 ptp->dev.devt = ptp->devid;
272 ptp->dev.class = ptp_class;
273 ptp->dev.parent = parent;
274 ptp->dev.groups = ptp->pin_attr_groups;
275 ptp->dev.release = ptp_clock_release;
276 dev_set_drvdata(&ptp->dev, ptp);
277 dev_set_name(&ptp->dev, "ptp%d", ptp->index);
279 /* Create a posix clock and link it to the device. */
280 err = posix_clock_register(&ptp->clock, &ptp->dev);
282 pr_err("failed to create posix clock\n");
290 pps_unregister_source(ptp->pps_source);
292 ptp_cleanup_pin_groups(ptp);
295 kthread_destroy_worker(ptp->kworker);
297 mutex_destroy(&ptp->tsevq_mux);
298 mutex_destroy(&ptp->pincfg_mux);
299 ida_simple_remove(&ptp_clocks_map, index);
305 EXPORT_SYMBOL(ptp_clock_register);
307 int ptp_clock_unregister(struct ptp_clock *ptp)
310 wake_up_interruptible(&ptp->tsev_wq);
313 kthread_cancel_delayed_work_sync(&ptp->aux_work);
314 kthread_destroy_worker(ptp->kworker);
317 /* Release the clock's resources. */
319 pps_unregister_source(ptp->pps_source);
321 posix_clock_unregister(&ptp->clock);
325 EXPORT_SYMBOL(ptp_clock_unregister);
327 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
329 struct pps_event_time evt;
331 switch (event->type) {
333 case PTP_CLOCK_ALARM:
336 case PTP_CLOCK_EXTTS:
337 enqueue_external_timestamp(&ptp->tsevq, event);
338 wake_up_interruptible(&ptp->tsev_wq);
343 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
346 case PTP_CLOCK_PPSUSR:
347 pps_event(ptp->pps_source, &event->pps_times,
348 PTP_PPS_EVENT, NULL);
352 EXPORT_SYMBOL(ptp_clock_event);
354 int ptp_clock_index(struct ptp_clock *ptp)
358 EXPORT_SYMBOL(ptp_clock_index);
360 int ptp_find_pin(struct ptp_clock *ptp,
361 enum ptp_pin_function func, unsigned int chan)
363 struct ptp_pin_desc *pin = NULL;
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];
374 mutex_unlock(&ptp->pincfg_mux);
378 EXPORT_SYMBOL(ptp_find_pin);
380 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
382 return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
384 EXPORT_SYMBOL(ptp_schedule_worker);
386 /* module operations */
388 static void __exit ptp_exit(void)
390 class_destroy(ptp_class);
391 unregister_chrdev_region(ptp_devt, MINORMASK + 1);
392 ida_destroy(&ptp_clocks_map);
395 static int __init ptp_init(void)
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);
405 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
407 pr_err("ptp: failed to allocate device region\n");
411 ptp_class->dev_groups = ptp_groups;
412 pr_info("PTP clock support registered\n");
416 class_destroy(ptp_class);
420 subsys_initcall(ptp_init);
421 module_exit(ptp_exit);
423 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
424 MODULE_DESCRIPTION("PTP clocks support");
425 MODULE_LICENSE("GPL");