135728b82SThomas Gleixner // SPDX-License-Identifier: GPL-2.0+ 20606f422SRichard Cochran /* 358c5fc2bSThomas Gleixner * Support for dynamic clock devices 40606f422SRichard Cochran * 50606f422SRichard Cochran * Copyright (C) 2010 OMICRON electronics GmbH 60606f422SRichard Cochran */ 70606f422SRichard Cochran #include <linux/device.h> 86e5fdeedSPaul Gortmaker #include <linux/export.h> 90606f422SRichard Cochran #include <linux/file.h> 100606f422SRichard Cochran #include <linux/posix-clock.h> 110606f422SRichard Cochran #include <linux/slab.h> 120606f422SRichard Cochran #include <linux/syscalls.h> 130606f422SRichard Cochran #include <linux/uaccess.h> 140606f422SRichard Cochran 15bab0aae9SThomas Gleixner #include "posix-timers.h" 16bab0aae9SThomas Gleixner 170606f422SRichard Cochran /* 180606f422SRichard Cochran * Returns NULL if the posix_clock instance attached to 'fp' is old and stale. 190606f422SRichard Cochran */ 200606f422SRichard Cochran static struct posix_clock *get_posix_clock(struct file *fp) 210606f422SRichard Cochran { 220606f422SRichard Cochran struct posix_clock *clk = fp->private_data; 230606f422SRichard Cochran 241791f881SRichard Cochran down_read(&clk->rwsem); 250606f422SRichard Cochran 260606f422SRichard Cochran if (!clk->zombie) 270606f422SRichard Cochran return clk; 280606f422SRichard Cochran 291791f881SRichard Cochran up_read(&clk->rwsem); 300606f422SRichard Cochran 310606f422SRichard Cochran return NULL; 320606f422SRichard Cochran } 330606f422SRichard Cochran 340606f422SRichard Cochran static void put_posix_clock(struct posix_clock *clk) 350606f422SRichard Cochran { 361791f881SRichard Cochran up_read(&clk->rwsem); 370606f422SRichard Cochran } 380606f422SRichard Cochran 390606f422SRichard Cochran static ssize_t posix_clock_read(struct file *fp, char __user *buf, 400606f422SRichard Cochran size_t count, loff_t *ppos) 410606f422SRichard Cochran { 420606f422SRichard Cochran struct posix_clock *clk = get_posix_clock(fp); 430606f422SRichard Cochran int err = -EINVAL; 440606f422SRichard Cochran 450606f422SRichard Cochran if (!clk) 460606f422SRichard Cochran return -ENODEV; 470606f422SRichard Cochran 480606f422SRichard Cochran if (clk->ops.read) 490606f422SRichard Cochran err = clk->ops.read(clk, fp->f_flags, buf, count); 500606f422SRichard Cochran 510606f422SRichard Cochran put_posix_clock(clk); 520606f422SRichard Cochran 530606f422SRichard Cochran return err; 540606f422SRichard Cochran } 550606f422SRichard Cochran 569dd95748SAl Viro static __poll_t posix_clock_poll(struct file *fp, poll_table *wait) 570606f422SRichard Cochran { 580606f422SRichard Cochran struct posix_clock *clk = get_posix_clock(fp); 599dd95748SAl Viro __poll_t result = 0; 600606f422SRichard Cochran 610606f422SRichard Cochran if (!clk) 62a9a08845SLinus Torvalds return EPOLLERR; 630606f422SRichard Cochran 640606f422SRichard Cochran if (clk->ops.poll) 650606f422SRichard Cochran result = clk->ops.poll(clk, fp, wait); 660606f422SRichard Cochran 670606f422SRichard Cochran put_posix_clock(clk); 680606f422SRichard Cochran 690606f422SRichard Cochran return result; 700606f422SRichard Cochran } 710606f422SRichard Cochran 720606f422SRichard Cochran static long posix_clock_ioctl(struct file *fp, 730606f422SRichard Cochran unsigned int cmd, unsigned long arg) 740606f422SRichard Cochran { 750606f422SRichard Cochran struct posix_clock *clk = get_posix_clock(fp); 760606f422SRichard Cochran int err = -ENOTTY; 770606f422SRichard Cochran 780606f422SRichard Cochran if (!clk) 790606f422SRichard Cochran return -ENODEV; 800606f422SRichard Cochran 810606f422SRichard Cochran if (clk->ops.ioctl) 820606f422SRichard Cochran err = clk->ops.ioctl(clk, cmd, arg); 830606f422SRichard Cochran 840606f422SRichard Cochran put_posix_clock(clk); 850606f422SRichard Cochran 860606f422SRichard Cochran return err; 870606f422SRichard Cochran } 880606f422SRichard Cochran 890606f422SRichard Cochran #ifdef CONFIG_COMPAT 900606f422SRichard Cochran static long posix_clock_compat_ioctl(struct file *fp, 910606f422SRichard Cochran unsigned int cmd, unsigned long arg) 920606f422SRichard Cochran { 930606f422SRichard Cochran struct posix_clock *clk = get_posix_clock(fp); 940606f422SRichard Cochran int err = -ENOTTY; 950606f422SRichard Cochran 960606f422SRichard Cochran if (!clk) 970606f422SRichard Cochran return -ENODEV; 980606f422SRichard Cochran 990606f422SRichard Cochran if (clk->ops.ioctl) 1000606f422SRichard Cochran err = clk->ops.ioctl(clk, cmd, arg); 1010606f422SRichard Cochran 1020606f422SRichard Cochran put_posix_clock(clk); 1030606f422SRichard Cochran 1040606f422SRichard Cochran return err; 1050606f422SRichard Cochran } 1060606f422SRichard Cochran #endif 1070606f422SRichard Cochran 1080606f422SRichard Cochran static int posix_clock_open(struct inode *inode, struct file *fp) 1090606f422SRichard Cochran { 1100606f422SRichard Cochran int err; 1110606f422SRichard Cochran struct posix_clock *clk = 1120606f422SRichard Cochran container_of(inode->i_cdev, struct posix_clock, cdev); 1130606f422SRichard Cochran 1141791f881SRichard Cochran down_read(&clk->rwsem); 1150606f422SRichard Cochran 1160606f422SRichard Cochran if (clk->zombie) { 1170606f422SRichard Cochran err = -ENODEV; 1180606f422SRichard Cochran goto out; 1190606f422SRichard Cochran } 1200606f422SRichard Cochran if (clk->ops.open) 1210606f422SRichard Cochran err = clk->ops.open(clk, fp->f_mode); 1220606f422SRichard Cochran else 1230606f422SRichard Cochran err = 0; 1240606f422SRichard Cochran 1250606f422SRichard Cochran if (!err) { 126a33121e5SVladis Dronov get_device(clk->dev); 1270606f422SRichard Cochran fp->private_data = clk; 1280606f422SRichard Cochran } 1290606f422SRichard Cochran out: 1301791f881SRichard Cochran up_read(&clk->rwsem); 1310606f422SRichard Cochran return err; 1320606f422SRichard Cochran } 1330606f422SRichard Cochran 1340606f422SRichard Cochran static int posix_clock_release(struct inode *inode, struct file *fp) 1350606f422SRichard Cochran { 1360606f422SRichard Cochran struct posix_clock *clk = fp->private_data; 1370606f422SRichard Cochran int err = 0; 1380606f422SRichard Cochran 1390606f422SRichard Cochran if (clk->ops.release) 1400606f422SRichard Cochran err = clk->ops.release(clk); 1410606f422SRichard Cochran 142a33121e5SVladis Dronov put_device(clk->dev); 1430606f422SRichard Cochran 1440606f422SRichard Cochran fp->private_data = NULL; 1450606f422SRichard Cochran 1460606f422SRichard Cochran return err; 1470606f422SRichard Cochran } 1480606f422SRichard Cochran 1490606f422SRichard Cochran static const struct file_operations posix_clock_file_operations = { 1500606f422SRichard Cochran .owner = THIS_MODULE, 1510606f422SRichard Cochran .llseek = no_llseek, 1520606f422SRichard Cochran .read = posix_clock_read, 1530606f422SRichard Cochran .poll = posix_clock_poll, 1540606f422SRichard Cochran .unlocked_ioctl = posix_clock_ioctl, 1550606f422SRichard Cochran .open = posix_clock_open, 1560606f422SRichard Cochran .release = posix_clock_release, 1570606f422SRichard Cochran #ifdef CONFIG_COMPAT 1580606f422SRichard Cochran .compat_ioctl = posix_clock_compat_ioctl, 1590606f422SRichard Cochran #endif 1600606f422SRichard Cochran }; 1610606f422SRichard Cochran 162a33121e5SVladis Dronov int posix_clock_register(struct posix_clock *clk, struct device *dev) 1630606f422SRichard Cochran { 1640606f422SRichard Cochran int err; 1650606f422SRichard Cochran 1661791f881SRichard Cochran init_rwsem(&clk->rwsem); 1670606f422SRichard Cochran 1680606f422SRichard Cochran cdev_init(&clk->cdev, &posix_clock_file_operations); 169a33121e5SVladis Dronov err = cdev_device_add(&clk->cdev, dev); 170a33121e5SVladis Dronov if (err) { 171a33121e5SVladis Dronov pr_err("%s unable to add device %d:%d\n", 172a33121e5SVladis Dronov dev_name(dev), MAJOR(dev->devt), MINOR(dev->devt)); 1730606f422SRichard Cochran return err; 1740606f422SRichard Cochran } 175a33121e5SVladis Dronov clk->cdev.owner = clk->ops.owner; 176a33121e5SVladis Dronov clk->dev = dev; 177a33121e5SVladis Dronov 178a33121e5SVladis Dronov return 0; 179a33121e5SVladis Dronov } 1800606f422SRichard Cochran EXPORT_SYMBOL_GPL(posix_clock_register); 1810606f422SRichard Cochran 1820606f422SRichard Cochran void posix_clock_unregister(struct posix_clock *clk) 1830606f422SRichard Cochran { 184a33121e5SVladis Dronov cdev_device_del(&clk->cdev, clk->dev); 1850606f422SRichard Cochran 1861791f881SRichard Cochran down_write(&clk->rwsem); 1870606f422SRichard Cochran clk->zombie = true; 1881791f881SRichard Cochran up_write(&clk->rwsem); 1890606f422SRichard Cochran 190a33121e5SVladis Dronov put_device(clk->dev); 1910606f422SRichard Cochran } 1920606f422SRichard Cochran EXPORT_SYMBOL_GPL(posix_clock_unregister); 1930606f422SRichard Cochran 1940606f422SRichard Cochran struct posix_clock_desc { 1950606f422SRichard Cochran struct file *fp; 1960606f422SRichard Cochran struct posix_clock *clk; 1970606f422SRichard Cochran }; 1980606f422SRichard Cochran 1990606f422SRichard Cochran static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd) 2000606f422SRichard Cochran { 20129f1b2b0SNick Desaulniers struct file *fp = fget(clockid_to_fd(id)); 2020606f422SRichard Cochran int err = -EINVAL; 2030606f422SRichard Cochran 2040606f422SRichard Cochran if (!fp) 2050606f422SRichard Cochran return err; 2060606f422SRichard Cochran 2070606f422SRichard Cochran if (fp->f_op->open != posix_clock_open || !fp->private_data) 2080606f422SRichard Cochran goto out; 2090606f422SRichard Cochran 2100606f422SRichard Cochran cd->fp = fp; 2110606f422SRichard Cochran cd->clk = get_posix_clock(fp); 2120606f422SRichard Cochran 2130606f422SRichard Cochran err = cd->clk ? 0 : -ENODEV; 2140606f422SRichard Cochran out: 2150606f422SRichard Cochran if (err) 2160606f422SRichard Cochran fput(fp); 2170606f422SRichard Cochran return err; 2180606f422SRichard Cochran } 2190606f422SRichard Cochran 2200606f422SRichard Cochran static void put_clock_desc(struct posix_clock_desc *cd) 2210606f422SRichard Cochran { 2220606f422SRichard Cochran put_posix_clock(cd->clk); 2230606f422SRichard Cochran fput(cd->fp); 2240606f422SRichard Cochran } 2250606f422SRichard Cochran 226ead25417SDeepa Dinamani static int pc_clock_adjtime(clockid_t id, struct __kernel_timex *tx) 2270606f422SRichard Cochran { 2280606f422SRichard Cochran struct posix_clock_desc cd; 2290606f422SRichard Cochran int err; 2300606f422SRichard Cochran 2310606f422SRichard Cochran err = get_clock_desc(id, &cd); 2320606f422SRichard Cochran if (err) 2330606f422SRichard Cochran return err; 2340606f422SRichard Cochran 2356e6823d1STorben Hohn if ((cd.fp->f_mode & FMODE_WRITE) == 0) { 2366e6823d1STorben Hohn err = -EACCES; 2376e6823d1STorben Hohn goto out; 2386e6823d1STorben Hohn } 2396e6823d1STorben Hohn 2400606f422SRichard Cochran if (cd.clk->ops.clock_adjtime) 2410606f422SRichard Cochran err = cd.clk->ops.clock_adjtime(cd.clk, tx); 2420606f422SRichard Cochran else 2430606f422SRichard Cochran err = -EOPNOTSUPP; 2446e6823d1STorben Hohn out: 2450606f422SRichard Cochran put_clock_desc(&cd); 2460606f422SRichard Cochran 2470606f422SRichard Cochran return err; 2480606f422SRichard Cochran } 2490606f422SRichard Cochran 2503c9c12f4SDeepa Dinamani static int pc_clock_gettime(clockid_t id, struct timespec64 *ts) 2510606f422SRichard Cochran { 2520606f422SRichard Cochran struct posix_clock_desc cd; 2530606f422SRichard Cochran int err; 2540606f422SRichard Cochran 2550606f422SRichard Cochran err = get_clock_desc(id, &cd); 2560606f422SRichard Cochran if (err) 2570606f422SRichard Cochran return err; 2580606f422SRichard Cochran 2593c9c12f4SDeepa Dinamani if (cd.clk->ops.clock_gettime) 2603c9c12f4SDeepa Dinamani err = cd.clk->ops.clock_gettime(cd.clk, ts); 2610606f422SRichard Cochran else 2620606f422SRichard Cochran err = -EOPNOTSUPP; 2630606f422SRichard Cochran 2640606f422SRichard Cochran put_clock_desc(&cd); 2650606f422SRichard Cochran 2660606f422SRichard Cochran return err; 2670606f422SRichard Cochran } 2680606f422SRichard Cochran 269d2e3e0caSDeepa Dinamani static int pc_clock_getres(clockid_t id, struct timespec64 *ts) 2700606f422SRichard Cochran { 2710606f422SRichard Cochran struct posix_clock_desc cd; 2720606f422SRichard Cochran int err; 2730606f422SRichard Cochran 2740606f422SRichard Cochran err = get_clock_desc(id, &cd); 2750606f422SRichard Cochran if (err) 2760606f422SRichard Cochran return err; 2770606f422SRichard Cochran 278d2e3e0caSDeepa Dinamani if (cd.clk->ops.clock_getres) 279d2e3e0caSDeepa Dinamani err = cd.clk->ops.clock_getres(cd.clk, ts); 2800606f422SRichard Cochran else 2810606f422SRichard Cochran err = -EOPNOTSUPP; 2820606f422SRichard Cochran 2830606f422SRichard Cochran put_clock_desc(&cd); 2840606f422SRichard Cochran 2850606f422SRichard Cochran return err; 2860606f422SRichard Cochran } 2870606f422SRichard Cochran 2880fe6afe3SDeepa Dinamani static int pc_clock_settime(clockid_t id, const struct timespec64 *ts) 2890606f422SRichard Cochran { 2900606f422SRichard Cochran struct posix_clock_desc cd; 2910606f422SRichard Cochran int err; 2920606f422SRichard Cochran 2930606f422SRichard Cochran err = get_clock_desc(id, &cd); 2940606f422SRichard Cochran if (err) 2950606f422SRichard Cochran return err; 2960606f422SRichard Cochran 2976e6823d1STorben Hohn if ((cd.fp->f_mode & FMODE_WRITE) == 0) { 2986e6823d1STorben Hohn err = -EACCES; 2996e6823d1STorben Hohn goto out; 3006e6823d1STorben Hohn } 3016e6823d1STorben Hohn 3020606f422SRichard Cochran if (cd.clk->ops.clock_settime) 3030fe6afe3SDeepa Dinamani err = cd.clk->ops.clock_settime(cd.clk, ts); 3040606f422SRichard Cochran else 3050606f422SRichard Cochran err = -EOPNOTSUPP; 3066e6823d1STorben Hohn out: 3070606f422SRichard Cochran put_clock_desc(&cd); 3080606f422SRichard Cochran 3090606f422SRichard Cochran return err; 3100606f422SRichard Cochran } 3110606f422SRichard Cochran 312d3ba5a9aSChristoph Hellwig const struct k_clock clock_posix_dynamic = { 3130606f422SRichard Cochran .clock_getres = pc_clock_getres, 3140606f422SRichard Cochran .clock_set = pc_clock_settime, 3150606f422SRichard Cochran .clock_get = pc_clock_gettime, 3160606f422SRichard Cochran .clock_adj = pc_clock_adjtime, 3170606f422SRichard Cochran }; 318