xref: /linux/drivers/ptp/ptp_chardev.c (revision e9f0878c4b2004ac19581274c1ae4c61ae3ca70e)
1 /*
2  * PTP 1588 clock support - character device implementation.
3  *
4  * Copyright (C) 2010 OMICRON electronics GmbH
5  *
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.
10  *
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.
15  *
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.
19  */
20 #include <linux/module.h>
21 #include <linux/posix-clock.h>
22 #include <linux/poll.h>
23 #include <linux/sched.h>
24 #include <linux/slab.h>
25 #include <linux/timekeeping.h>
26 
27 #include "ptp_private.h"
28 
29 static int ptp_disable_pinfunc(struct ptp_clock_info *ops,
30 			       enum ptp_pin_function func, unsigned int chan)
31 {
32 	struct ptp_clock_request rq;
33 	int err = 0;
34 
35 	memset(&rq, 0, sizeof(rq));
36 
37 	switch (func) {
38 	case PTP_PF_NONE:
39 		break;
40 	case PTP_PF_EXTTS:
41 		rq.type = PTP_CLK_REQ_EXTTS;
42 		rq.extts.index = chan;
43 		err = ops->enable(ops, &rq, 0);
44 		break;
45 	case PTP_PF_PEROUT:
46 		rq.type = PTP_CLK_REQ_PEROUT;
47 		rq.perout.index = chan;
48 		err = ops->enable(ops, &rq, 0);
49 		break;
50 	case PTP_PF_PHYSYNC:
51 		break;
52 	default:
53 		return -EINVAL;
54 	}
55 
56 	return err;
57 }
58 
59 int ptp_set_pinfunc(struct ptp_clock *ptp, unsigned int pin,
60 		    enum ptp_pin_function func, unsigned int chan)
61 {
62 	struct ptp_clock_info *info = ptp->info;
63 	struct ptp_pin_desc *pin1 = NULL, *pin2 = &info->pin_config[pin];
64 	unsigned int i;
65 
66 	/* Check to see if any other pin previously had this function. */
67 	for (i = 0; i < info->n_pins; i++) {
68 		if (info->pin_config[i].func == func &&
69 		    info->pin_config[i].chan == chan) {
70 			pin1 = &info->pin_config[i];
71 			break;
72 		}
73 	}
74 	if (pin1 && i == pin)
75 		return 0;
76 
77 	/* Check the desired function and channel. */
78 	switch (func) {
79 	case PTP_PF_NONE:
80 		break;
81 	case PTP_PF_EXTTS:
82 		if (chan >= info->n_ext_ts)
83 			return -EINVAL;
84 		break;
85 	case PTP_PF_PEROUT:
86 		if (chan >= info->n_per_out)
87 			return -EINVAL;
88 		break;
89 	case PTP_PF_PHYSYNC:
90 		if (chan != 0)
91 			return -EINVAL;
92 		break;
93 	default:
94 		return -EINVAL;
95 	}
96 
97 	if (info->verify(info, pin, func, chan)) {
98 		pr_err("driver cannot use function %u on pin %u\n", func, chan);
99 		return -EOPNOTSUPP;
100 	}
101 
102 	/* Disable whatever function was previously assigned. */
103 	if (pin1) {
104 		ptp_disable_pinfunc(info, func, chan);
105 		pin1->func = PTP_PF_NONE;
106 		pin1->chan = 0;
107 	}
108 	ptp_disable_pinfunc(info, pin2->func, pin2->chan);
109 	pin2->func = func;
110 	pin2->chan = chan;
111 
112 	return 0;
113 }
114 
115 int ptp_open(struct posix_clock *pc, fmode_t fmode)
116 {
117 	return 0;
118 }
119 
120 long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
121 {
122 	struct ptp_clock_caps caps;
123 	struct ptp_clock_request req;
124 	struct ptp_sys_offset *sysoff = NULL;
125 	struct ptp_sys_offset_precise precise_offset;
126 	struct ptp_pin_desc pd;
127 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
128 	struct ptp_clock_info *ops = ptp->info;
129 	struct ptp_clock_time *pct;
130 	struct timespec64 ts;
131 	struct system_device_crosststamp xtstamp;
132 	int enable, err = 0;
133 	unsigned int i, pin_index;
134 
135 	switch (cmd) {
136 
137 	case PTP_CLOCK_GETCAPS:
138 		memset(&caps, 0, sizeof(caps));
139 		caps.max_adj = ptp->info->max_adj;
140 		caps.n_alarm = ptp->info->n_alarm;
141 		caps.n_ext_ts = ptp->info->n_ext_ts;
142 		caps.n_per_out = ptp->info->n_per_out;
143 		caps.pps = ptp->info->pps;
144 		caps.n_pins = ptp->info->n_pins;
145 		caps.cross_timestamping = ptp->info->getcrosststamp != NULL;
146 		if (copy_to_user((void __user *)arg, &caps, sizeof(caps)))
147 			err = -EFAULT;
148 		break;
149 
150 	case PTP_EXTTS_REQUEST:
151 		if (copy_from_user(&req.extts, (void __user *)arg,
152 				   sizeof(req.extts))) {
153 			err = -EFAULT;
154 			break;
155 		}
156 		if (req.extts.index >= ops->n_ext_ts) {
157 			err = -EINVAL;
158 			break;
159 		}
160 		req.type = PTP_CLK_REQ_EXTTS;
161 		enable = req.extts.flags & PTP_ENABLE_FEATURE ? 1 : 0;
162 		err = ops->enable(ops, &req, enable);
163 		break;
164 
165 	case PTP_PEROUT_REQUEST:
166 		if (copy_from_user(&req.perout, (void __user *)arg,
167 				   sizeof(req.perout))) {
168 			err = -EFAULT;
169 			break;
170 		}
171 		if (req.perout.index >= ops->n_per_out) {
172 			err = -EINVAL;
173 			break;
174 		}
175 		req.type = PTP_CLK_REQ_PEROUT;
176 		enable = req.perout.period.sec || req.perout.period.nsec;
177 		err = ops->enable(ops, &req, enable);
178 		break;
179 
180 	case PTP_ENABLE_PPS:
181 		if (!capable(CAP_SYS_TIME))
182 			return -EPERM;
183 		req.type = PTP_CLK_REQ_PPS;
184 		enable = arg ? 1 : 0;
185 		err = ops->enable(ops, &req, enable);
186 		break;
187 
188 	case PTP_SYS_OFFSET_PRECISE:
189 		if (!ptp->info->getcrosststamp) {
190 			err = -EOPNOTSUPP;
191 			break;
192 		}
193 		err = ptp->info->getcrosststamp(ptp->info, &xtstamp);
194 		if (err)
195 			break;
196 
197 		memset(&precise_offset, 0, sizeof(precise_offset));
198 		ts = ktime_to_timespec64(xtstamp.device);
199 		precise_offset.device.sec = ts.tv_sec;
200 		precise_offset.device.nsec = ts.tv_nsec;
201 		ts = ktime_to_timespec64(xtstamp.sys_realtime);
202 		precise_offset.sys_realtime.sec = ts.tv_sec;
203 		precise_offset.sys_realtime.nsec = ts.tv_nsec;
204 		ts = ktime_to_timespec64(xtstamp.sys_monoraw);
205 		precise_offset.sys_monoraw.sec = ts.tv_sec;
206 		precise_offset.sys_monoraw.nsec = ts.tv_nsec;
207 		if (copy_to_user((void __user *)arg, &precise_offset,
208 				 sizeof(precise_offset)))
209 			err = -EFAULT;
210 		break;
211 
212 	case PTP_SYS_OFFSET:
213 		sysoff = memdup_user((void __user *)arg, sizeof(*sysoff));
214 		if (IS_ERR(sysoff)) {
215 			err = PTR_ERR(sysoff);
216 			sysoff = NULL;
217 			break;
218 		}
219 		if (sysoff->n_samples > PTP_MAX_SAMPLES) {
220 			err = -EINVAL;
221 			break;
222 		}
223 		pct = &sysoff->ts[0];
224 		for (i = 0; i < sysoff->n_samples; i++) {
225 			ktime_get_real_ts64(&ts);
226 			pct->sec = ts.tv_sec;
227 			pct->nsec = ts.tv_nsec;
228 			pct++;
229 			ptp->info->gettime64(ptp->info, &ts);
230 			pct->sec = ts.tv_sec;
231 			pct->nsec = ts.tv_nsec;
232 			pct++;
233 		}
234 		ktime_get_real_ts64(&ts);
235 		pct->sec = ts.tv_sec;
236 		pct->nsec = ts.tv_nsec;
237 		if (copy_to_user((void __user *)arg, sysoff, sizeof(*sysoff)))
238 			err = -EFAULT;
239 		break;
240 
241 	case PTP_PIN_GETFUNC:
242 		if (copy_from_user(&pd, (void __user *)arg, sizeof(pd))) {
243 			err = -EFAULT;
244 			break;
245 		}
246 		pin_index = pd.index;
247 		if (pin_index >= ops->n_pins) {
248 			err = -EINVAL;
249 			break;
250 		}
251 		if (mutex_lock_interruptible(&ptp->pincfg_mux))
252 			return -ERESTARTSYS;
253 		pd = ops->pin_config[pin_index];
254 		mutex_unlock(&ptp->pincfg_mux);
255 		if (!err && copy_to_user((void __user *)arg, &pd, sizeof(pd)))
256 			err = -EFAULT;
257 		break;
258 
259 	case PTP_PIN_SETFUNC:
260 		if (copy_from_user(&pd, (void __user *)arg, sizeof(pd))) {
261 			err = -EFAULT;
262 			break;
263 		}
264 		pin_index = pd.index;
265 		if (pin_index >= ops->n_pins) {
266 			err = -EINVAL;
267 			break;
268 		}
269 		if (mutex_lock_interruptible(&ptp->pincfg_mux))
270 			return -ERESTARTSYS;
271 		err = ptp_set_pinfunc(ptp, pin_index, pd.func, pd.chan);
272 		mutex_unlock(&ptp->pincfg_mux);
273 		break;
274 
275 	default:
276 		err = -ENOTTY;
277 		break;
278 	}
279 
280 	kfree(sysoff);
281 	return err;
282 }
283 
284 __poll_t ptp_poll(struct posix_clock *pc, struct file *fp, poll_table *wait)
285 {
286 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
287 
288 	poll_wait(fp, &ptp->tsev_wq, wait);
289 
290 	return queue_cnt(&ptp->tsevq) ? EPOLLIN : 0;
291 }
292 
293 #define EXTTS_BUFSIZE (PTP_BUF_TIMESTAMPS * sizeof(struct ptp_extts_event))
294 
295 ssize_t ptp_read(struct posix_clock *pc,
296 		 uint rdflags, char __user *buf, size_t cnt)
297 {
298 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
299 	struct timestamp_event_queue *queue = &ptp->tsevq;
300 	struct ptp_extts_event *event;
301 	unsigned long flags;
302 	size_t qcnt, i;
303 	int result;
304 
305 	if (cnt % sizeof(struct ptp_extts_event) != 0)
306 		return -EINVAL;
307 
308 	if (cnt > EXTTS_BUFSIZE)
309 		cnt = EXTTS_BUFSIZE;
310 
311 	cnt = cnt / sizeof(struct ptp_extts_event);
312 
313 	if (mutex_lock_interruptible(&ptp->tsevq_mux))
314 		return -ERESTARTSYS;
315 
316 	if (wait_event_interruptible(ptp->tsev_wq,
317 				     ptp->defunct || queue_cnt(queue))) {
318 		mutex_unlock(&ptp->tsevq_mux);
319 		return -ERESTARTSYS;
320 	}
321 
322 	if (ptp->defunct) {
323 		mutex_unlock(&ptp->tsevq_mux);
324 		return -ENODEV;
325 	}
326 
327 	event = kmalloc(EXTTS_BUFSIZE, GFP_KERNEL);
328 	if (!event) {
329 		mutex_unlock(&ptp->tsevq_mux);
330 		return -ENOMEM;
331 	}
332 
333 	spin_lock_irqsave(&queue->lock, flags);
334 
335 	qcnt = queue_cnt(queue);
336 
337 	if (cnt > qcnt)
338 		cnt = qcnt;
339 
340 	for (i = 0; i < cnt; i++) {
341 		event[i] = queue->buf[queue->head];
342 		queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
343 	}
344 
345 	spin_unlock_irqrestore(&queue->lock, flags);
346 
347 	cnt = cnt * sizeof(struct ptp_extts_event);
348 
349 	mutex_unlock(&ptp->tsevq_mux);
350 
351 	result = cnt;
352 	if (copy_to_user(buf, event, cnt))
353 		result = -EFAULT;
354 
355 	kfree(event);
356 	return result;
357 }
358