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 /* Both WRITE_ONCE() are paired with READ_ONCE() in queue_cnt() */
59 if (!queue_free(queue))
60 WRITE_ONCE(queue->head, (queue->head + 1) % PTP_MAX_TIMESTAMPS);
61
62 WRITE_ONCE(queue->tail, (queue->tail + 1) % PTP_MAX_TIMESTAMPS);
63
64 spin_unlock_irqrestore(&queue->lock, flags);
65 }
66
scaled_ppm_to_ppb(long ppm)67 long scaled_ppm_to_ppb(long ppm)
68 {
69 /*
70 * The 'freq' field in the 'struct timex' is in parts per
71 * million, but with a 16 bit binary fractional field.
72 *
73 * We want to calculate
74 *
75 * ppb = scaled_ppm * 1000 / 2^16
76 *
77 * which simplifies to
78 *
79 * ppb = scaled_ppm * 125 / 2^13
80 */
81 s64 ppb = 1 + ppm;
82 ppb *= 125;
83 ppb >>= 13;
84 return (long) ppb;
85 }
86 EXPORT_SYMBOL(scaled_ppm_to_ppb);
87
88 /* posix clock implementation */
89
ptp_clock_getres(struct posix_clock * pc,struct timespec64 * tp)90 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
91 {
92 tp->tv_sec = 0;
93 tp->tv_nsec = 1;
94 return 0;
95 }
96
ptp_clock_settime(struct posix_clock * pc,const struct timespec64 * tp)97 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
98 {
99 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
100
101 return ptp->info->settime64(ptp->info, tp);
102 }
103
ptp_clock_gettime(struct posix_clock * pc,struct timespec64 * tp)104 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
105 {
106 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
107 int err;
108
109 if (ptp->info->gettimex64)
110 err = ptp->info->gettimex64(ptp->info, tp, NULL);
111 else
112 err = ptp->info->gettime64(ptp->info, tp);
113 return err;
114 }
115
ptp_clock_adjtime(struct posix_clock * pc,struct __kernel_timex * tx)116 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
117 {
118 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
119 struct ptp_clock_info *ops;
120 int err = -EOPNOTSUPP;
121
122 ops = ptp->info;
123
124 if (tx->modes & ADJ_SETOFFSET) {
125 struct timespec64 ts;
126 ktime_t kt;
127 s64 delta;
128
129 ts.tv_sec = tx->time.tv_sec;
130 ts.tv_nsec = tx->time.tv_usec;
131
132 if (!(tx->modes & ADJ_NANO))
133 ts.tv_nsec *= 1000;
134
135 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
136 return -EINVAL;
137
138 kt = timespec64_to_ktime(ts);
139 delta = ktime_to_ns(kt);
140 err = ops->adjtime(ops, delta);
141 } else if (tx->modes & ADJ_FREQUENCY) {
142 long ppb = scaled_ppm_to_ppb(tx->freq);
143 if (ppb > ops->max_adj || ppb < -ops->max_adj)
144 return -ERANGE;
145 if (ops->adjfine)
146 err = ops->adjfine(ops, tx->freq);
147 else
148 err = ops->adjfreq(ops, ppb);
149 ptp->dialed_frequency = tx->freq;
150 } else if (tx->modes == 0) {
151 tx->freq = ptp->dialed_frequency;
152 err = 0;
153 }
154
155 return err;
156 }
157
158 static struct posix_clock_operations ptp_clock_ops = {
159 .owner = THIS_MODULE,
160 .clock_adjtime = ptp_clock_adjtime,
161 .clock_gettime = ptp_clock_gettime,
162 .clock_getres = ptp_clock_getres,
163 .clock_settime = ptp_clock_settime,
164 .ioctl = ptp_ioctl,
165 .open = ptp_open,
166 .poll = ptp_poll,
167 .read = ptp_read,
168 };
169
ptp_clock_release(struct device * dev)170 static void ptp_clock_release(struct device *dev)
171 {
172 struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
173
174 ptp_cleanup_pin_groups(ptp);
175 mutex_destroy(&ptp->tsevq_mux);
176 mutex_destroy(&ptp->pincfg_mux);
177 ida_simple_remove(&ptp_clocks_map, ptp->index);
178 kfree(ptp);
179 }
180
ptp_aux_kworker(struct kthread_work * work)181 static void ptp_aux_kworker(struct kthread_work *work)
182 {
183 struct ptp_clock *ptp = container_of(work, struct ptp_clock,
184 aux_work.work);
185 struct ptp_clock_info *info = ptp->info;
186 long delay;
187
188 delay = info->do_aux_work(info);
189
190 if (delay >= 0)
191 kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
192 }
193
194 /* public interface */
195
ptp_clock_register(struct ptp_clock_info * info,struct device * parent)196 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
197 struct device *parent)
198 {
199 struct ptp_clock *ptp;
200 int err = 0, index, major = MAJOR(ptp_devt);
201
202 if (info->n_alarm > PTP_MAX_ALARMS)
203 return ERR_PTR(-EINVAL);
204
205 /* Initialize a clock structure. */
206 err = -ENOMEM;
207 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
208 if (ptp == NULL)
209 goto no_memory;
210
211 index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
212 if (index < 0) {
213 err = index;
214 goto no_slot;
215 }
216
217 ptp->clock.ops = ptp_clock_ops;
218 ptp->info = info;
219 ptp->devid = MKDEV(major, index);
220 ptp->index = index;
221 spin_lock_init(&ptp->tsevq.lock);
222 mutex_init(&ptp->tsevq_mux);
223 mutex_init(&ptp->pincfg_mux);
224 init_waitqueue_head(&ptp->tsev_wq);
225
226 if (ptp->info->do_aux_work) {
227 kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
228 ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
229 if (IS_ERR(ptp->kworker)) {
230 err = PTR_ERR(ptp->kworker);
231 pr_err("failed to create ptp aux_worker %d\n", err);
232 goto kworker_err;
233 }
234 }
235
236 err = ptp_populate_pin_groups(ptp);
237 if (err)
238 goto no_pin_groups;
239
240 /* Register a new PPS source. */
241 if (info->pps) {
242 struct pps_source_info pps;
243 memset(&pps, 0, sizeof(pps));
244 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
245 pps.mode = PTP_PPS_MODE;
246 pps.owner = info->owner;
247 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
248 if (IS_ERR(ptp->pps_source)) {
249 err = PTR_ERR(ptp->pps_source);
250 pr_err("failed to register pps source\n");
251 goto no_pps;
252 }
253 }
254
255 /* Initialize a new device of our class in our clock structure. */
256 device_initialize(&ptp->dev);
257 ptp->dev.devt = ptp->devid;
258 ptp->dev.class = ptp_class;
259 ptp->dev.parent = parent;
260 ptp->dev.groups = ptp->pin_attr_groups;
261 ptp->dev.release = ptp_clock_release;
262 dev_set_drvdata(&ptp->dev, ptp);
263 dev_set_name(&ptp->dev, "ptp%d", ptp->index);
264
265 /* Create a posix clock and link it to the device. */
266 err = posix_clock_register(&ptp->clock, &ptp->dev);
267 if (err) {
268 pr_err("failed to create posix clock\n");
269 goto no_clock;
270 }
271
272 return ptp;
273
274 no_clock:
275 if (ptp->pps_source)
276 pps_unregister_source(ptp->pps_source);
277 no_pps:
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 posix_clock_unregister(&ptp->clock);
308
309 return 0;
310 }
311 EXPORT_SYMBOL(ptp_clock_unregister);
312
ptp_clock_event(struct ptp_clock * ptp,struct ptp_clock_event * event)313 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
314 {
315 struct pps_event_time evt;
316
317 switch (event->type) {
318
319 case PTP_CLOCK_ALARM:
320 break;
321
322 case PTP_CLOCK_EXTTS:
323 enqueue_external_timestamp(&ptp->tsevq, event);
324 wake_up_interruptible(&ptp->tsev_wq);
325 break;
326
327 case PTP_CLOCK_PPS:
328 pps_get_ts(&evt);
329 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
330 break;
331
332 case PTP_CLOCK_PPSUSR:
333 pps_event(ptp->pps_source, &event->pps_times,
334 PTP_PPS_EVENT, NULL);
335 break;
336 }
337 }
338 EXPORT_SYMBOL(ptp_clock_event);
339
ptp_clock_index(struct ptp_clock * ptp)340 int ptp_clock_index(struct ptp_clock *ptp)
341 {
342 return ptp->index;
343 }
344 EXPORT_SYMBOL(ptp_clock_index);
345
ptp_find_pin(struct ptp_clock * ptp,enum ptp_pin_function func,unsigned int chan)346 int ptp_find_pin(struct ptp_clock *ptp,
347 enum ptp_pin_function func, unsigned int chan)
348 {
349 struct ptp_pin_desc *pin = NULL;
350 int i;
351
352 mutex_lock(&ptp->pincfg_mux);
353 for (i = 0; i < ptp->info->n_pins; i++) {
354 if (ptp->info->pin_config[i].func == func &&
355 ptp->info->pin_config[i].chan == chan) {
356 pin = &ptp->info->pin_config[i];
357 break;
358 }
359 }
360 mutex_unlock(&ptp->pincfg_mux);
361
362 return pin ? i : -1;
363 }
364 EXPORT_SYMBOL(ptp_find_pin);
365
ptp_schedule_worker(struct ptp_clock * ptp,unsigned long delay)366 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
367 {
368 return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
369 }
370 EXPORT_SYMBOL(ptp_schedule_worker);
371
372 /* module operations */
373
ptp_exit(void)374 static void __exit ptp_exit(void)
375 {
376 class_destroy(ptp_class);
377 unregister_chrdev_region(ptp_devt, MINORMASK + 1);
378 ida_destroy(&ptp_clocks_map);
379 }
380
ptp_init(void)381 static int __init ptp_init(void)
382 {
383 int err;
384
385 ptp_class = class_create(THIS_MODULE, "ptp");
386 if (IS_ERR(ptp_class)) {
387 pr_err("ptp: failed to allocate class\n");
388 return PTR_ERR(ptp_class);
389 }
390
391 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
392 if (err < 0) {
393 pr_err("ptp: failed to allocate device region\n");
394 goto no_region;
395 }
396
397 ptp_class->dev_groups = ptp_groups;
398 pr_info("PTP clock support registered\n");
399 return 0;
400
401 no_region:
402 class_destroy(ptp_class);
403 return err;
404 }
405
406 subsys_initcall(ptp_init);
407 module_exit(ptp_exit);
408
409 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
410 MODULE_DESCRIPTION("PTP clocks support");
411 MODULE_LICENSE("GPL");
412