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1/*
2 * posix-clock.c - support for dynamic clock devices
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/device.h>
21#include <linux/export.h>
22#include <linux/file.h>
23#include <linux/posix-clock.h>
24#include <linux/slab.h>
25#include <linux/syscalls.h>
26#include <linux/uaccess.h>
27
28static void delete_clock(struct kref *kref);
29
30/*
31 * Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
32 */
33static struct posix_clock *get_posix_clock(struct file *fp)
34{
35 struct posix_clock *clk = fp->private_data;
36
37 down_read(&clk->rwsem);
38
39 if (!clk->zombie)
40 return clk;
41
42 up_read(&clk->rwsem);
43
44 return NULL;
45}
46
47static void put_posix_clock(struct posix_clock *clk)
48{
49 up_read(&clk->rwsem);
50}
51
52static ssize_t posix_clock_read(struct file *fp, char __user *buf,
53 size_t count, loff_t *ppos)
54{
55 struct posix_clock *clk = get_posix_clock(fp);
56 int err = -EINVAL;
57
58 if (!clk)
59 return -ENODEV;
60
61 if (clk->ops.read)
62 err = clk->ops.read(clk, fp->f_flags, buf, count);
63
64 put_posix_clock(clk);
65
66 return err;
67}
68
69static unsigned int posix_clock_poll(struct file *fp, poll_table *wait)
70{
71 struct posix_clock *clk = get_posix_clock(fp);
72 unsigned int result = 0;
73
74 if (!clk)
75 return POLLERR;
76
77 if (clk->ops.poll)
78 result = clk->ops.poll(clk, fp, wait);
79
80 put_posix_clock(clk);
81
82 return result;
83}
84
85static int posix_clock_fasync(int fd, struct file *fp, int on)
86{
87 struct posix_clock *clk = get_posix_clock(fp);
88 int err = 0;
89
90 if (!clk)
91 return -ENODEV;
92
93 if (clk->ops.fasync)
94 err = clk->ops.fasync(clk, fd, fp, on);
95
96 put_posix_clock(clk);
97
98 return err;
99}
100
101static int posix_clock_mmap(struct file *fp, struct vm_area_struct *vma)
102{
103 struct posix_clock *clk = get_posix_clock(fp);
104 int err = -ENODEV;
105
106 if (!clk)
107 return -ENODEV;
108
109 if (clk->ops.mmap)
110 err = clk->ops.mmap(clk, vma);
111
112 put_posix_clock(clk);
113
114 return err;
115}
116
117static long posix_clock_ioctl(struct file *fp,
118 unsigned int cmd, unsigned long arg)
119{
120 struct posix_clock *clk = get_posix_clock(fp);
121 int err = -ENOTTY;
122
123 if (!clk)
124 return -ENODEV;
125
126 if (clk->ops.ioctl)
127 err = clk->ops.ioctl(clk, cmd, arg);
128
129 put_posix_clock(clk);
130
131 return err;
132}
133
134#ifdef CONFIG_COMPAT
135static long posix_clock_compat_ioctl(struct file *fp,
136 unsigned int cmd, unsigned long arg)
137{
138 struct posix_clock *clk = get_posix_clock(fp);
139 int err = -ENOTTY;
140
141 if (!clk)
142 return -ENODEV;
143
144 if (clk->ops.ioctl)
145 err = clk->ops.ioctl(clk, cmd, arg);
146
147 put_posix_clock(clk);
148
149 return err;
150}
151#endif
152
153static int posix_clock_open(struct inode *inode, struct file *fp)
154{
155 int err;
156 struct posix_clock *clk =
157 container_of(inode->i_cdev, struct posix_clock, cdev);
158
159 down_read(&clk->rwsem);
160
161 if (clk->zombie) {
162 err = -ENODEV;
163 goto out;
164 }
165 if (clk->ops.open)
166 err = clk->ops.open(clk, fp->f_mode);
167 else
168 err = 0;
169
170 if (!err) {
171 kref_get(&clk->kref);
172 fp->private_data = clk;
173 }
174out:
175 up_read(&clk->rwsem);
176 return err;
177}
178
179static int posix_clock_release(struct inode *inode, struct file *fp)
180{
181 struct posix_clock *clk = fp->private_data;
182 int err = 0;
183
184 if (clk->ops.release)
185 err = clk->ops.release(clk);
186
187 kref_put(&clk->kref, delete_clock);
188
189 fp->private_data = NULL;
190
191 return err;
192}
193
194static const struct file_operations posix_clock_file_operations = {
195 .owner = THIS_MODULE,
196 .llseek = no_llseek,
197 .read = posix_clock_read,
198 .poll = posix_clock_poll,
199 .unlocked_ioctl = posix_clock_ioctl,
200 .open = posix_clock_open,
201 .release = posix_clock_release,
202 .fasync = posix_clock_fasync,
203 .mmap = posix_clock_mmap,
204#ifdef CONFIG_COMPAT
205 .compat_ioctl = posix_clock_compat_ioctl,
206#endif
207};
208
209int posix_clock_register(struct posix_clock *clk, dev_t devid)
210{
211 int err;
212
213 kref_init(&clk->kref);
214 init_rwsem(&clk->rwsem);
215
216 cdev_init(&clk->cdev, &posix_clock_file_operations);
217 clk->cdev.owner = clk->ops.owner;
218 err = cdev_add(&clk->cdev, devid, 1);
219
220 return err;
221}
222EXPORT_SYMBOL_GPL(posix_clock_register);
223
224static void delete_clock(struct kref *kref)
225{
226 struct posix_clock *clk = container_of(kref, struct posix_clock, kref);
227
228 if (clk->release)
229 clk->release(clk);
230}
231
232void posix_clock_unregister(struct posix_clock *clk)
233{
234 cdev_del(&clk->cdev);
235
236 down_write(&clk->rwsem);
237 clk->zombie = true;
238 up_write(&clk->rwsem);
239
240 kref_put(&clk->kref, delete_clock);
241}
242EXPORT_SYMBOL_GPL(posix_clock_unregister);
243
244struct posix_clock_desc {
245 struct file *fp;
246 struct posix_clock *clk;
247};
248
249static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
250{
251 struct file *fp = fget(CLOCKID_TO_FD(id));
252 int err = -EINVAL;
253
254 if (!fp)
255 return err;
256
257 if (fp->f_op->open != posix_clock_open || !fp->private_data)
258 goto out;
259
260 cd->fp = fp;
261 cd->clk = get_posix_clock(fp);
262
263 err = cd->clk ? 0 : -ENODEV;
264out:
265 if (err)
266 fput(fp);
267 return err;
268}
269
270static void put_clock_desc(struct posix_clock_desc *cd)
271{
272 put_posix_clock(cd->clk);
273 fput(cd->fp);
274}
275
276static int pc_clock_adjtime(clockid_t id, struct timex *tx)
277{
278 struct posix_clock_desc cd;
279 int err;
280
281 err = get_clock_desc(id, &cd);
282 if (err)
283 return err;
284
285 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
286 err = -EACCES;
287 goto out;
288 }
289
290 if (cd.clk->ops.clock_adjtime)
291 err = cd.clk->ops.clock_adjtime(cd.clk, tx);
292 else
293 err = -EOPNOTSUPP;
294out:
295 put_clock_desc(&cd);
296
297 return err;
298}
299
300static int pc_clock_gettime(clockid_t id, struct timespec *ts)
301{
302 struct posix_clock_desc cd;
303 int err;
304
305 err = get_clock_desc(id, &cd);
306 if (err)
307 return err;
308
309 if (cd.clk->ops.clock_gettime)
310 err = cd.clk->ops.clock_gettime(cd.clk, ts);
311 else
312 err = -EOPNOTSUPP;
313
314 put_clock_desc(&cd);
315
316 return err;
317}
318
319static int pc_clock_getres(clockid_t id, struct timespec *ts)
320{
321 struct posix_clock_desc cd;
322 int err;
323
324 err = get_clock_desc(id, &cd);
325 if (err)
326 return err;
327
328 if (cd.clk->ops.clock_getres)
329 err = cd.clk->ops.clock_getres(cd.clk, ts);
330 else
331 err = -EOPNOTSUPP;
332
333 put_clock_desc(&cd);
334
335 return err;
336}
337
338static int pc_clock_settime(clockid_t id, const struct timespec *ts)
339{
340 struct posix_clock_desc cd;
341 int err;
342
343 err = get_clock_desc(id, &cd);
344 if (err)
345 return err;
346
347 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
348 err = -EACCES;
349 goto out;
350 }
351
352 if (cd.clk->ops.clock_settime)
353 err = cd.clk->ops.clock_settime(cd.clk, ts);
354 else
355 err = -EOPNOTSUPP;
356out:
357 put_clock_desc(&cd);
358
359 return err;
360}
361
362static int pc_timer_create(struct k_itimer *kit)
363{
364 clockid_t id = kit->it_clock;
365 struct posix_clock_desc cd;
366 int err;
367
368 err = get_clock_desc(id, &cd);
369 if (err)
370 return err;
371
372 if (cd.clk->ops.timer_create)
373 err = cd.clk->ops.timer_create(cd.clk, kit);
374 else
375 err = -EOPNOTSUPP;
376
377 put_clock_desc(&cd);
378
379 return err;
380}
381
382static int pc_timer_delete(struct k_itimer *kit)
383{
384 clockid_t id = kit->it_clock;
385 struct posix_clock_desc cd;
386 int err;
387
388 err = get_clock_desc(id, &cd);
389 if (err)
390 return err;
391
392 if (cd.clk->ops.timer_delete)
393 err = cd.clk->ops.timer_delete(cd.clk, kit);
394 else
395 err = -EOPNOTSUPP;
396
397 put_clock_desc(&cd);
398
399 return err;
400}
401
402static void pc_timer_gettime(struct k_itimer *kit, struct itimerspec *ts)
403{
404 clockid_t id = kit->it_clock;
405 struct posix_clock_desc cd;
406
407 if (get_clock_desc(id, &cd))
408 return;
409
410 if (cd.clk->ops.timer_gettime)
411 cd.clk->ops.timer_gettime(cd.clk, kit, ts);
412
413 put_clock_desc(&cd);
414}
415
416static int pc_timer_settime(struct k_itimer *kit, int flags,
417 struct itimerspec *ts, struct itimerspec *old)
418{
419 clockid_t id = kit->it_clock;
420 struct posix_clock_desc cd;
421 int err;
422
423 err = get_clock_desc(id, &cd);
424 if (err)
425 return err;
426
427 if (cd.clk->ops.timer_settime)
428 err = cd.clk->ops.timer_settime(cd.clk, kit, flags, ts, old);
429 else
430 err = -EOPNOTSUPP;
431
432 put_clock_desc(&cd);
433
434 return err;
435}
436
437struct k_clock clock_posix_dynamic = {
438 .clock_getres = pc_clock_getres,
439 .clock_set = pc_clock_settime,
440 .clock_get = pc_clock_gettime,
441 .clock_adj = pc_clock_adjtime,
442 .timer_create = pc_timer_create,
443 .timer_set = pc_timer_settime,
444 .timer_del = pc_timer_delete,
445 .timer_get = pc_timer_gettime,
446};
1/*
2 * posix-clock.c - support for dynamic clock devices
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/device.h>
21#include <linux/file.h>
22#include <linux/posix-clock.h>
23#include <linux/slab.h>
24#include <linux/syscalls.h>
25#include <linux/uaccess.h>
26
27static void delete_clock(struct kref *kref);
28
29/*
30 * Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
31 */
32static struct posix_clock *get_posix_clock(struct file *fp)
33{
34 struct posix_clock *clk = fp->private_data;
35
36 down_read(&clk->rwsem);
37
38 if (!clk->zombie)
39 return clk;
40
41 up_read(&clk->rwsem);
42
43 return NULL;
44}
45
46static void put_posix_clock(struct posix_clock *clk)
47{
48 up_read(&clk->rwsem);
49}
50
51static ssize_t posix_clock_read(struct file *fp, char __user *buf,
52 size_t count, loff_t *ppos)
53{
54 struct posix_clock *clk = get_posix_clock(fp);
55 int err = -EINVAL;
56
57 if (!clk)
58 return -ENODEV;
59
60 if (clk->ops.read)
61 err = clk->ops.read(clk, fp->f_flags, buf, count);
62
63 put_posix_clock(clk);
64
65 return err;
66}
67
68static unsigned int posix_clock_poll(struct file *fp, poll_table *wait)
69{
70 struct posix_clock *clk = get_posix_clock(fp);
71 int result = 0;
72
73 if (!clk)
74 return -ENODEV;
75
76 if (clk->ops.poll)
77 result = clk->ops.poll(clk, fp, wait);
78
79 put_posix_clock(clk);
80
81 return result;
82}
83
84static int posix_clock_fasync(int fd, struct file *fp, int on)
85{
86 struct posix_clock *clk = get_posix_clock(fp);
87 int err = 0;
88
89 if (!clk)
90 return -ENODEV;
91
92 if (clk->ops.fasync)
93 err = clk->ops.fasync(clk, fd, fp, on);
94
95 put_posix_clock(clk);
96
97 return err;
98}
99
100static int posix_clock_mmap(struct file *fp, struct vm_area_struct *vma)
101{
102 struct posix_clock *clk = get_posix_clock(fp);
103 int err = -ENODEV;
104
105 if (!clk)
106 return -ENODEV;
107
108 if (clk->ops.mmap)
109 err = clk->ops.mmap(clk, vma);
110
111 put_posix_clock(clk);
112
113 return err;
114}
115
116static long posix_clock_ioctl(struct file *fp,
117 unsigned int cmd, unsigned long arg)
118{
119 struct posix_clock *clk = get_posix_clock(fp);
120 int err = -ENOTTY;
121
122 if (!clk)
123 return -ENODEV;
124
125 if (clk->ops.ioctl)
126 err = clk->ops.ioctl(clk, cmd, arg);
127
128 put_posix_clock(clk);
129
130 return err;
131}
132
133#ifdef CONFIG_COMPAT
134static long posix_clock_compat_ioctl(struct file *fp,
135 unsigned int cmd, unsigned long arg)
136{
137 struct posix_clock *clk = get_posix_clock(fp);
138 int err = -ENOTTY;
139
140 if (!clk)
141 return -ENODEV;
142
143 if (clk->ops.ioctl)
144 err = clk->ops.ioctl(clk, cmd, arg);
145
146 put_posix_clock(clk);
147
148 return err;
149}
150#endif
151
152static int posix_clock_open(struct inode *inode, struct file *fp)
153{
154 int err;
155 struct posix_clock *clk =
156 container_of(inode->i_cdev, struct posix_clock, cdev);
157
158 down_read(&clk->rwsem);
159
160 if (clk->zombie) {
161 err = -ENODEV;
162 goto out;
163 }
164 if (clk->ops.open)
165 err = clk->ops.open(clk, fp->f_mode);
166 else
167 err = 0;
168
169 if (!err) {
170 kref_get(&clk->kref);
171 fp->private_data = clk;
172 }
173out:
174 up_read(&clk->rwsem);
175 return err;
176}
177
178static int posix_clock_release(struct inode *inode, struct file *fp)
179{
180 struct posix_clock *clk = fp->private_data;
181 int err = 0;
182
183 if (clk->ops.release)
184 err = clk->ops.release(clk);
185
186 kref_put(&clk->kref, delete_clock);
187
188 fp->private_data = NULL;
189
190 return err;
191}
192
193static const struct file_operations posix_clock_file_operations = {
194 .owner = THIS_MODULE,
195 .llseek = no_llseek,
196 .read = posix_clock_read,
197 .poll = posix_clock_poll,
198 .unlocked_ioctl = posix_clock_ioctl,
199 .open = posix_clock_open,
200 .release = posix_clock_release,
201 .fasync = posix_clock_fasync,
202 .mmap = posix_clock_mmap,
203#ifdef CONFIG_COMPAT
204 .compat_ioctl = posix_clock_compat_ioctl,
205#endif
206};
207
208int posix_clock_register(struct posix_clock *clk, dev_t devid)
209{
210 int err;
211
212 kref_init(&clk->kref);
213 init_rwsem(&clk->rwsem);
214
215 cdev_init(&clk->cdev, &posix_clock_file_operations);
216 clk->cdev.owner = clk->ops.owner;
217 err = cdev_add(&clk->cdev, devid, 1);
218
219 return err;
220}
221EXPORT_SYMBOL_GPL(posix_clock_register);
222
223static void delete_clock(struct kref *kref)
224{
225 struct posix_clock *clk = container_of(kref, struct posix_clock, kref);
226
227 if (clk->release)
228 clk->release(clk);
229}
230
231void posix_clock_unregister(struct posix_clock *clk)
232{
233 cdev_del(&clk->cdev);
234
235 down_write(&clk->rwsem);
236 clk->zombie = true;
237 up_write(&clk->rwsem);
238
239 kref_put(&clk->kref, delete_clock);
240}
241EXPORT_SYMBOL_GPL(posix_clock_unregister);
242
243struct posix_clock_desc {
244 struct file *fp;
245 struct posix_clock *clk;
246};
247
248static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
249{
250 struct file *fp = fget(CLOCKID_TO_FD(id));
251 int err = -EINVAL;
252
253 if (!fp)
254 return err;
255
256 if (fp->f_op->open != posix_clock_open || !fp->private_data)
257 goto out;
258
259 cd->fp = fp;
260 cd->clk = get_posix_clock(fp);
261
262 err = cd->clk ? 0 : -ENODEV;
263out:
264 if (err)
265 fput(fp);
266 return err;
267}
268
269static void put_clock_desc(struct posix_clock_desc *cd)
270{
271 put_posix_clock(cd->clk);
272 fput(cd->fp);
273}
274
275static int pc_clock_adjtime(clockid_t id, struct timex *tx)
276{
277 struct posix_clock_desc cd;
278 int err;
279
280 err = get_clock_desc(id, &cd);
281 if (err)
282 return err;
283
284 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
285 err = -EACCES;
286 goto out;
287 }
288
289 if (cd.clk->ops.clock_adjtime)
290 err = cd.clk->ops.clock_adjtime(cd.clk, tx);
291 else
292 err = -EOPNOTSUPP;
293out:
294 put_clock_desc(&cd);
295
296 return err;
297}
298
299static int pc_clock_gettime(clockid_t id, struct timespec *ts)
300{
301 struct posix_clock_desc cd;
302 int err;
303
304 err = get_clock_desc(id, &cd);
305 if (err)
306 return err;
307
308 if (cd.clk->ops.clock_gettime)
309 err = cd.clk->ops.clock_gettime(cd.clk, ts);
310 else
311 err = -EOPNOTSUPP;
312
313 put_clock_desc(&cd);
314
315 return err;
316}
317
318static int pc_clock_getres(clockid_t id, struct timespec *ts)
319{
320 struct posix_clock_desc cd;
321 int err;
322
323 err = get_clock_desc(id, &cd);
324 if (err)
325 return err;
326
327 if (cd.clk->ops.clock_getres)
328 err = cd.clk->ops.clock_getres(cd.clk, ts);
329 else
330 err = -EOPNOTSUPP;
331
332 put_clock_desc(&cd);
333
334 return err;
335}
336
337static int pc_clock_settime(clockid_t id, const struct timespec *ts)
338{
339 struct posix_clock_desc cd;
340 int err;
341
342 err = get_clock_desc(id, &cd);
343 if (err)
344 return err;
345
346 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
347 err = -EACCES;
348 goto out;
349 }
350
351 if (cd.clk->ops.clock_settime)
352 err = cd.clk->ops.clock_settime(cd.clk, ts);
353 else
354 err = -EOPNOTSUPP;
355out:
356 put_clock_desc(&cd);
357
358 return err;
359}
360
361static int pc_timer_create(struct k_itimer *kit)
362{
363 clockid_t id = kit->it_clock;
364 struct posix_clock_desc cd;
365 int err;
366
367 err = get_clock_desc(id, &cd);
368 if (err)
369 return err;
370
371 if (cd.clk->ops.timer_create)
372 err = cd.clk->ops.timer_create(cd.clk, kit);
373 else
374 err = -EOPNOTSUPP;
375
376 put_clock_desc(&cd);
377
378 return err;
379}
380
381static int pc_timer_delete(struct k_itimer *kit)
382{
383 clockid_t id = kit->it_clock;
384 struct posix_clock_desc cd;
385 int err;
386
387 err = get_clock_desc(id, &cd);
388 if (err)
389 return err;
390
391 if (cd.clk->ops.timer_delete)
392 err = cd.clk->ops.timer_delete(cd.clk, kit);
393 else
394 err = -EOPNOTSUPP;
395
396 put_clock_desc(&cd);
397
398 return err;
399}
400
401static void pc_timer_gettime(struct k_itimer *kit, struct itimerspec *ts)
402{
403 clockid_t id = kit->it_clock;
404 struct posix_clock_desc cd;
405
406 if (get_clock_desc(id, &cd))
407 return;
408
409 if (cd.clk->ops.timer_gettime)
410 cd.clk->ops.timer_gettime(cd.clk, kit, ts);
411
412 put_clock_desc(&cd);
413}
414
415static int pc_timer_settime(struct k_itimer *kit, int flags,
416 struct itimerspec *ts, struct itimerspec *old)
417{
418 clockid_t id = kit->it_clock;
419 struct posix_clock_desc cd;
420 int err;
421
422 err = get_clock_desc(id, &cd);
423 if (err)
424 return err;
425
426 if (cd.clk->ops.timer_settime)
427 err = cd.clk->ops.timer_settime(cd.clk, kit, flags, ts, old);
428 else
429 err = -EOPNOTSUPP;
430
431 put_clock_desc(&cd);
432
433 return err;
434}
435
436struct k_clock clock_posix_dynamic = {
437 .clock_getres = pc_clock_getres,
438 .clock_set = pc_clock_settime,
439 .clock_get = pc_clock_gettime,
440 .clock_adj = pc_clock_adjtime,
441 .timer_create = pc_timer_create,
442 .timer_set = pc_timer_settime,
443 .timer_del = pc_timer_delete,
444 .timer_get = pc_timer_gettime,
445};