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;
132 fp->private_data = pccontext;
134 err = clk->ops.open(pccontext, fp->f_mode);
139 get_device(clk->dev);
142 up_read(&clk->rwsem);
146 static int posix_clock_release(struct inode *inode, struct file *fp)
148 struct posix_clock_context *pccontext = fp->private_data;
149 struct posix_clock *clk;
154 clk = pccontext->clk;
156 if (clk->ops.release)
157 err = clk->ops.release(pccontext);
159 put_device(clk->dev);
162 fp->private_data = NULL;
167 static const struct file_operations posix_clock_file_operations = {
168 .owner = THIS_MODULE,
170 .read = posix_clock_read,
171 .poll = posix_clock_poll,
172 .unlocked_ioctl = posix_clock_ioctl,
173 .open = posix_clock_open,
174 .release = posix_clock_release,
176 .compat_ioctl = posix_clock_compat_ioctl,
180 int posix_clock_register(struct posix_clock *clk, struct device *dev)
184 init_rwsem(&clk->rwsem);
186 cdev_init(&clk->cdev, &posix_clock_file_operations);
187 err = cdev_device_add(&clk->cdev, dev);
189 pr_err("%s unable to add device %d:%d\n",
190 dev_name(dev), MAJOR(dev->devt), MINOR(dev->devt));
193 clk->cdev.owner = clk->ops.owner;
198 EXPORT_SYMBOL_GPL(posix_clock_register);
200 void posix_clock_unregister(struct posix_clock *clk)
202 cdev_device_del(&clk->cdev, clk->dev);
204 down_write(&clk->rwsem);
206 up_write(&clk->rwsem);
208 put_device(clk->dev);
210 EXPORT_SYMBOL_GPL(posix_clock_unregister);
212 struct posix_clock_desc {
214 struct posix_clock *clk;
217 static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
219 struct file *fp = fget(clockid_to_fd(id));
225 if (fp->f_op->open != posix_clock_open || !fp->private_data)
229 cd->clk = get_posix_clock(fp);
231 err = cd->clk ? 0 : -ENODEV;
238 static void put_clock_desc(struct posix_clock_desc *cd)
240 put_posix_clock(cd->clk);
244 static int pc_clock_adjtime(clockid_t id, struct __kernel_timex *tx)
246 struct posix_clock_desc cd;
249 err = get_clock_desc(id, &cd);
253 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
258 if (cd.clk->ops.clock_adjtime)
259 err = cd.clk->ops.clock_adjtime(cd.clk, tx);
268 static int pc_clock_gettime(clockid_t id, struct timespec64 *ts)
270 struct posix_clock_desc cd;
273 err = get_clock_desc(id, &cd);
277 if (cd.clk->ops.clock_gettime)
278 err = cd.clk->ops.clock_gettime(cd.clk, ts);
287 static int pc_clock_getres(clockid_t id, struct timespec64 *ts)
289 struct posix_clock_desc cd;
292 err = get_clock_desc(id, &cd);
296 if (cd.clk->ops.clock_getres)
297 err = cd.clk->ops.clock_getres(cd.clk, ts);
306 static int pc_clock_settime(clockid_t id, const struct timespec64 *ts)
308 struct posix_clock_desc cd;
311 err = get_clock_desc(id, &cd);
315 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
320 if (cd.clk->ops.clock_settime)
321 err = cd.clk->ops.clock_settime(cd.clk, ts);
330 const struct k_clock clock_posix_dynamic = {
331 .clock_getres = pc_clock_getres,
332 .clock_set = pc_clock_settime,
333 .clock_get_timespec = pc_clock_gettime,
334 .clock_adj = pc_clock_adjtime,