xref: /openbmc/linux/drivers/ptp/ptp_clock.c (revision e7253313)
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