1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * PTP 1588 clock support
5 * Copyright (C) 2010 OMICRON electronics GmbH
8 #include <linux/device.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>
20 #include "ptp_private.h"
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)
29 static dev_t ptp_devt;
30 static struct class *ptp_class;
32 static DEFINE_IDA(ptp_clocks_map);
34 /* time stamp event queue operations */
36 static inline int queue_free(struct timestamp_event_queue *q)
38 return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
41 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
42 struct ptp_clock_event *src)
44 struct ptp_extts_event *dst;
49 seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
51 spin_lock_irqsave(&queue->lock, flags);
53 dst = &queue->buf[queue->tail];
54 dst->index = src->index;
56 dst->t.nsec = remainder;
58 if (!queue_free(queue))
59 queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
61 queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;
63 spin_unlock_irqrestore(&queue->lock, flags);
66 s32 scaled_ppm_to_ppb(long ppm)
69 * The 'freq' field in the 'struct timex' is in parts per
70 * million, but with a 16 bit binary fractional field.
72 * We want to calculate
74 * ppb = scaled_ppm * 1000 / 2^16
78 * ppb = scaled_ppm * 125 / 2^13
85 EXPORT_SYMBOL(scaled_ppm_to_ppb);
87 /* posix clock implementation */
89 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
96 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
98 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
100 return ptp->info->settime64(ptp->info, tp);
103 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
105 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
108 if (ptp->info->gettimex64)
109 err = ptp->info->gettimex64(ptp->info, tp, NULL);
111 err = ptp->info->gettime64(ptp->info, tp);
115 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
117 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
118 struct ptp_clock_info *ops;
119 int err = -EOPNOTSUPP;
123 if (tx->modes & ADJ_SETOFFSET) {
124 struct timespec64 ts;
128 ts.tv_sec = tx->time.tv_sec;
129 ts.tv_nsec = tx->time.tv_usec;
131 if (!(tx->modes & ADJ_NANO))
134 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
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)
145 err = ops->adjfine(ops, tx->freq);
147 err = ops->adjfreq(ops, ppb);
148 ptp->dialed_frequency = tx->freq;
149 } else if (tx->modes == 0) {
150 tx->freq = ptp->dialed_frequency;
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,
169 static void delete_ptp_clock(struct posix_clock *pc)
171 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
173 mutex_destroy(&ptp->tsevq_mux);
174 mutex_destroy(&ptp->pincfg_mux);
175 ida_simple_remove(&ptp_clocks_map, ptp->index);
179 static void ptp_aux_kworker(struct kthread_work *work)
181 struct ptp_clock *ptp = container_of(work, struct ptp_clock,
183 struct ptp_clock_info *info = ptp->info;
186 delay = info->do_aux_work(info);
189 kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
192 /* public interface */
194 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
195 struct device *parent)
197 struct ptp_clock *ptp;
198 int err = 0, index, major = MAJOR(ptp_devt);
200 if (info->n_alarm > PTP_MAX_ALARMS)
201 return ERR_PTR(-EINVAL);
203 /* Initialize a clock structure. */
205 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
209 index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
215 ptp->clock.ops = ptp_clock_ops;
216 ptp->clock.release = delete_ptp_clock;
218 ptp->devid = MKDEV(major, 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);
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);
235 err = ptp_populate_pin_groups(ptp);
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);
248 /* Register a new PPS source. */
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");
263 /* Create a posix clock. */
264 err = posix_clock_register(&ptp->clock, ptp->devid);
266 pr_err("failed to create posix clock\n");
274 pps_unregister_source(ptp->pps_source);
276 device_destroy(ptp_class, ptp->devid);
278 ptp_cleanup_pin_groups(ptp);
281 kthread_destroy_worker(ptp->kworker);
283 mutex_destroy(&ptp->tsevq_mux);
284 mutex_destroy(&ptp->pincfg_mux);
285 ida_simple_remove(&ptp_clocks_map, index);
291 EXPORT_SYMBOL(ptp_clock_register);
293 int ptp_clock_unregister(struct ptp_clock *ptp)
296 wake_up_interruptible(&ptp->tsev_wq);
299 kthread_cancel_delayed_work_sync(&ptp->aux_work);
300 kthread_destroy_worker(ptp->kworker);
303 /* Release the clock's resources. */
305 pps_unregister_source(ptp->pps_source);
307 device_destroy(ptp_class, ptp->devid);
308 ptp_cleanup_pin_groups(ptp);
310 posix_clock_unregister(&ptp->clock);
313 EXPORT_SYMBOL(ptp_clock_unregister);
315 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
317 struct pps_event_time evt;
319 switch (event->type) {
321 case PTP_CLOCK_ALARM:
324 case PTP_CLOCK_EXTTS:
325 enqueue_external_timestamp(&ptp->tsevq, event);
326 wake_up_interruptible(&ptp->tsev_wq);
331 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
334 case PTP_CLOCK_PPSUSR:
335 pps_event(ptp->pps_source, &event->pps_times,
336 PTP_PPS_EVENT, NULL);
340 EXPORT_SYMBOL(ptp_clock_event);
342 int ptp_clock_index(struct ptp_clock *ptp)
346 EXPORT_SYMBOL(ptp_clock_index);
348 int ptp_find_pin(struct ptp_clock *ptp,
349 enum ptp_pin_function func, unsigned int chan)
351 struct ptp_pin_desc *pin = NULL;
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];
362 mutex_unlock(&ptp->pincfg_mux);
366 EXPORT_SYMBOL(ptp_find_pin);
368 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
370 return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
372 EXPORT_SYMBOL(ptp_schedule_worker);
374 /* module operations */
376 static void __exit ptp_exit(void)
378 class_destroy(ptp_class);
379 unregister_chrdev_region(ptp_devt, MINORMASK + 1);
380 ida_destroy(&ptp_clocks_map);
383 static int __init ptp_init(void)
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);
393 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
395 pr_err("ptp: failed to allocate device region\n");
399 ptp_class->dev_groups = ptp_groups;
400 pr_info("PTP clock support registered\n");
404 class_destroy(ptp_class);
408 subsys_initcall(ptp_init);
409 module_exit(ptp_exit);
411 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
412 MODULE_DESCRIPTION("PTP clocks support");
413 MODULE_LICENSE("GPL");