2 * posix-clock.c - support for dynamic clock devices
4 * Copyright (C) 2010 OMICRON electronics GmbH
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.
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.
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.
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>
27 static void delete_clock(struct kref *kref);
30 * Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
32 static struct posix_clock *get_posix_clock(struct file *fp)
34 struct posix_clock *clk = fp->private_data;
36 down_read(&clk->rwsem);
46 static void put_posix_clock(struct posix_clock *clk)
51 static ssize_t posix_clock_read(struct file *fp, char __user *buf,
52 size_t count, loff_t *ppos)
54 struct posix_clock *clk = get_posix_clock(fp);
61 err = clk->ops.read(clk, fp->f_flags, buf, count);
68 static unsigned int posix_clock_poll(struct file *fp, poll_table *wait)
70 struct posix_clock *clk = get_posix_clock(fp);
77 result = clk->ops.poll(clk, fp, wait);
84 static int posix_clock_fasync(int fd, struct file *fp, int on)
86 struct posix_clock *clk = get_posix_clock(fp);
93 err = clk->ops.fasync(clk, fd, fp, on);
100 static int posix_clock_mmap(struct file *fp, struct vm_area_struct *vma)
102 struct posix_clock *clk = get_posix_clock(fp);
109 err = clk->ops.mmap(clk, vma);
111 put_posix_clock(clk);
116 static long posix_clock_ioctl(struct file *fp,
117 unsigned int cmd, unsigned long arg)
119 struct posix_clock *clk = get_posix_clock(fp);
126 err = clk->ops.ioctl(clk, cmd, arg);
128 put_posix_clock(clk);
134 static long posix_clock_compat_ioctl(struct file *fp,
135 unsigned int cmd, unsigned long arg)
137 struct posix_clock *clk = get_posix_clock(fp);
144 err = clk->ops.ioctl(clk, cmd, arg);
146 put_posix_clock(clk);
152 static int posix_clock_open(struct inode *inode, struct file *fp)
155 struct posix_clock *clk =
156 container_of(inode->i_cdev, struct posix_clock, cdev);
158 down_read(&clk->rwsem);
165 err = clk->ops.open(clk, fp->f_mode);
170 kref_get(&clk->kref);
171 fp->private_data = clk;
174 up_read(&clk->rwsem);
178 static int posix_clock_release(struct inode *inode, struct file *fp)
180 struct posix_clock *clk = fp->private_data;
183 if (clk->ops.release)
184 err = clk->ops.release(clk);
186 kref_put(&clk->kref, delete_clock);
188 fp->private_data = NULL;
193 static const struct file_operations posix_clock_file_operations = {
194 .owner = THIS_MODULE,
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,
204 .compat_ioctl = posix_clock_compat_ioctl,
208 int posix_clock_register(struct posix_clock *clk, dev_t devid)
212 kref_init(&clk->kref);
213 init_rwsem(&clk->rwsem);
215 cdev_init(&clk->cdev, &posix_clock_file_operations);
216 clk->cdev.owner = clk->ops.owner;
217 err = cdev_add(&clk->cdev, devid, 1);
221 EXPORT_SYMBOL_GPL(posix_clock_register);
223 static void delete_clock(struct kref *kref)
225 struct posix_clock *clk = container_of(kref, struct posix_clock, kref);
231 void posix_clock_unregister(struct posix_clock *clk)
233 cdev_del(&clk->cdev);
235 down_write(&clk->rwsem);
237 up_write(&clk->rwsem);
239 kref_put(&clk->kref, delete_clock);
241 EXPORT_SYMBOL_GPL(posix_clock_unregister);
243 struct posix_clock_desc {
245 struct posix_clock *clk;
248 static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
250 struct file *fp = fget(CLOCKID_TO_FD(id));
256 if (fp->f_op->open != posix_clock_open || !fp->private_data)
260 cd->clk = get_posix_clock(fp);
262 err = cd->clk ? 0 : -ENODEV;
269 static void put_clock_desc(struct posix_clock_desc *cd)
271 put_posix_clock(cd->clk);
275 static int pc_clock_adjtime(clockid_t id, struct timex *tx)
277 struct posix_clock_desc cd;
280 err = get_clock_desc(id, &cd);
284 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
289 if (cd.clk->ops.clock_adjtime)
290 err = cd.clk->ops.clock_adjtime(cd.clk, tx);
299 static int pc_clock_gettime(clockid_t id, struct timespec *ts)
301 struct posix_clock_desc cd;
304 err = get_clock_desc(id, &cd);
308 if (cd.clk->ops.clock_gettime)
309 err = cd.clk->ops.clock_gettime(cd.clk, ts);
318 static int pc_clock_getres(clockid_t id, struct timespec *ts)
320 struct posix_clock_desc cd;
323 err = get_clock_desc(id, &cd);
327 if (cd.clk->ops.clock_getres)
328 err = cd.clk->ops.clock_getres(cd.clk, ts);
337 static int pc_clock_settime(clockid_t id, const struct timespec *ts)
339 struct posix_clock_desc cd;
342 err = get_clock_desc(id, &cd);
346 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
351 if (cd.clk->ops.clock_settime)
352 err = cd.clk->ops.clock_settime(cd.clk, ts);
361 static int pc_timer_create(struct k_itimer *kit)
363 clockid_t id = kit->it_clock;
364 struct posix_clock_desc cd;
367 err = get_clock_desc(id, &cd);
371 if (cd.clk->ops.timer_create)
372 err = cd.clk->ops.timer_create(cd.clk, kit);
381 static int pc_timer_delete(struct k_itimer *kit)
383 clockid_t id = kit->it_clock;
384 struct posix_clock_desc cd;
387 err = get_clock_desc(id, &cd);
391 if (cd.clk->ops.timer_delete)
392 err = cd.clk->ops.timer_delete(cd.clk, kit);
401 static void pc_timer_gettime(struct k_itimer *kit, struct itimerspec *ts)
403 clockid_t id = kit->it_clock;
404 struct posix_clock_desc cd;
406 if (get_clock_desc(id, &cd))
409 if (cd.clk->ops.timer_gettime)
410 cd.clk->ops.timer_gettime(cd.clk, kit, ts);
415 static int pc_timer_settime(struct k_itimer *kit, int flags,
416 struct itimerspec *ts, struct itimerspec *old)
418 clockid_t id = kit->it_clock;
419 struct posix_clock_desc cd;
422 err = get_clock_desc(id, &cd);
426 if (cd.clk->ops.timer_settime)
427 err = cd.clk->ops.timer_settime(cd.clk, kit, flags, ts, old);
436 struct 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,