1 // SPDX-License-Identifier: GPL-2.0+
3 * Support for dynamic clock devices
5 * Copyright (C) 2010 OMICRON electronics GmbH
7 #include <linux/device.h>
8 #include <linux/export.h>
9 #include <linux/file.h>
10 #include <linux/posix-clock.h>
11 #include <linux/slab.h>
12 #include <linux/syscalls.h>
13 #include <linux/uaccess.h>
15 #include "posix-timers.h"
18 * Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
20 static struct posix_clock *get_posix_clock(struct file *fp)
22 struct posix_clock_context *pccontext = fp->private_data;
23 struct posix_clock *clk = pccontext->clk;
25 down_read(&clk->rwsem);
35 static void put_posix_clock(struct posix_clock *clk)
40 static ssize_t posix_clock_read(struct file *fp, char __user *buf,
41 size_t count, loff_t *ppos)
43 struct posix_clock_context *pccontext = fp->private_data;
44 struct posix_clock *clk = get_posix_clock(fp);
51 err = clk->ops.read(pccontext, fp->f_flags, buf, count);
58 static __poll_t posix_clock_poll(struct file *fp, poll_table *wait)
60 struct posix_clock_context *pccontext = fp->private_data;
61 struct posix_clock *clk = get_posix_clock(fp);
68 result = clk->ops.poll(pccontext, fp, wait);
75 static long posix_clock_ioctl(struct file *fp,
76 unsigned int cmd, unsigned long arg)
78 struct posix_clock_context *pccontext = fp->private_data;
79 struct posix_clock *clk = get_posix_clock(fp);
86 err = clk->ops.ioctl(pccontext, cmd, arg);
94 static long posix_clock_compat_ioctl(struct file *fp,
95 unsigned int cmd, unsigned long arg)
97 struct posix_clock_context *pccontext = fp->private_data;
98 struct posix_clock *clk = get_posix_clock(fp);
105 err = clk->ops.ioctl(pccontext, cmd, arg);
107 put_posix_clock(clk);
113 static int posix_clock_open(struct inode *inode, struct file *fp)
116 struct posix_clock *clk =
117 container_of(inode->i_cdev, struct posix_clock, cdev);
118 struct posix_clock_context *pccontext;
120 down_read(&clk->rwsem);
126 pccontext = kzalloc(sizeof(*pccontext), GFP_KERNEL);
131 pccontext->clk = clk;
133 err = clk->ops.open(pccontext, fp->f_mode);
140 fp->private_data = pccontext;
141 get_device(clk->dev);
144 up_read(&clk->rwsem);
148 static int posix_clock_release(struct inode *inode, struct file *fp)
150 struct posix_clock_context *pccontext = fp->private_data;
151 struct posix_clock *clk;
156 clk = pccontext->clk;
158 if (clk->ops.release)
159 err = clk->ops.release(pccontext);
161 put_device(clk->dev);
164 fp->private_data = NULL;
169 static const struct file_operations posix_clock_file_operations = {
170 .owner = THIS_MODULE,
172 .read = posix_clock_read,
173 .poll = posix_clock_poll,
174 .unlocked_ioctl = posix_clock_ioctl,
175 .open = posix_clock_open,
176 .release = posix_clock_release,
178 .compat_ioctl = posix_clock_compat_ioctl,
182 int posix_clock_register(struct posix_clock *clk, struct device *dev)
186 init_rwsem(&clk->rwsem);
188 cdev_init(&clk->cdev, &posix_clock_file_operations);
189 err = cdev_device_add(&clk->cdev, dev);
191 pr_err("%s unable to add device %d:%d\n",
192 dev_name(dev), MAJOR(dev->devt), MINOR(dev->devt));
195 clk->cdev.owner = clk->ops.owner;
200 EXPORT_SYMBOL_GPL(posix_clock_register);
202 void posix_clock_unregister(struct posix_clock *clk)
204 cdev_device_del(&clk->cdev, clk->dev);
206 down_write(&clk->rwsem);
208 up_write(&clk->rwsem);
210 put_device(clk->dev);
212 EXPORT_SYMBOL_GPL(posix_clock_unregister);
214 struct posix_clock_desc {
216 struct posix_clock *clk;
219 static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
221 struct file *fp = fget(clockid_to_fd(id));
227 if (fp->f_op->open != posix_clock_open || !fp->private_data)
231 cd->clk = get_posix_clock(fp);
233 err = cd->clk ? 0 : -ENODEV;
240 static void put_clock_desc(struct posix_clock_desc *cd)
242 put_posix_clock(cd->clk);
246 static int pc_clock_adjtime(clockid_t id, struct __kernel_timex *tx)
248 struct posix_clock_desc cd;
251 err = get_clock_desc(id, &cd);
255 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
260 if (cd.clk->ops.clock_adjtime)
261 err = cd.clk->ops.clock_adjtime(cd.clk, tx);
270 static int pc_clock_gettime(clockid_t id, struct timespec64 *ts)
272 struct posix_clock_desc cd;
275 err = get_clock_desc(id, &cd);
279 if (cd.clk->ops.clock_gettime)
280 err = cd.clk->ops.clock_gettime(cd.clk, ts);
289 static int pc_clock_getres(clockid_t id, struct timespec64 *ts)
291 struct posix_clock_desc cd;
294 err = get_clock_desc(id, &cd);
298 if (cd.clk->ops.clock_getres)
299 err = cd.clk->ops.clock_getres(cd.clk, ts);
308 static int pc_clock_settime(clockid_t id, const struct timespec64 *ts)
310 struct posix_clock_desc cd;
313 err = get_clock_desc(id, &cd);
317 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
322 if (cd.clk->ops.clock_settime)
323 err = cd.clk->ops.clock_settime(cd.clk, ts);
332 const struct k_clock clock_posix_dynamic = {
333 .clock_getres = pc_clock_getres,
334 .clock_set = pc_clock_settime,
335 .clock_get_timespec = pc_clock_gettime,
336 .clock_adj = pc_clock_adjtime,