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
queue_free(struct timestamp_event_queue * q)36 static inline int queue_free(struct timestamp_event_queue *q)
37 {
38 return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
39 }
40
enqueue_external_timestamp(struct timestamp_event_queue * queue,struct ptp_clock_event * src)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
scaled_ppm_to_ppb(long ppm)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
ptp_clock_getres(struct posix_clock * pc,struct timespec64 * tp)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
ptp_clock_settime(struct posix_clock * pc,const struct timespec64 * tp)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
ptp_clock_gettime(struct posix_clock * pc,struct timespec64 * tp)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
ptp_clock_adjtime(struct posix_clock * pc,struct __kernel_timex * tx)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
delete_ptp_clock(struct posix_clock * pc)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
ptp_aux_kworker(struct kthread_work * work)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
ptp_clock_register(struct ptp_clock_info * info,struct device * parent)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
ptp_clock_unregister(struct ptp_clock * ptp)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
ptp_clock_event(struct ptp_clock * ptp,struct ptp_clock_event * event)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
ptp_clock_index(struct ptp_clock * ptp)342 int ptp_clock_index(struct ptp_clock *ptp)
343 {
344 return ptp->index;
345 }
346 EXPORT_SYMBOL(ptp_clock_index);
347
ptp_find_pin(struct ptp_clock * ptp,enum ptp_pin_function func,unsigned int chan)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
ptp_schedule_worker(struct ptp_clock * ptp,unsigned long delay)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
ptp_exit(void)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
ptp_init(void)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
