10606f422SRichard Cochran /* 20606f422SRichard Cochran * posix-clock.c - support for dynamic clock devices 30606f422SRichard Cochran * 40606f422SRichard Cochran * Copyright (C) 2010 OMICRON electronics GmbH 50606f422SRichard Cochran * 60606f422SRichard Cochran * This program is free software; you can redistribute it and/or modify 70606f422SRichard Cochran * it under the terms of the GNU General Public License as published by 80606f422SRichard Cochran * the Free Software Foundation; either version 2 of the License, or 90606f422SRichard Cochran * (at your option) any later version. 100606f422SRichard Cochran * 110606f422SRichard Cochran * This program is distributed in the hope that it will be useful, 120606f422SRichard Cochran * but WITHOUT ANY WARRANTY; without even the implied warranty of 130606f422SRichard Cochran * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 140606f422SRichard Cochran * GNU General Public License for more details. 150606f422SRichard Cochran * 160606f422SRichard Cochran * You should have received a copy of the GNU General Public License 170606f422SRichard Cochran * along with this program; if not, write to the Free Software 180606f422SRichard Cochran * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 190606f422SRichard Cochran */ 200606f422SRichard Cochran #include <linux/device.h> 216e5fdeedSPaul Gortmaker #include <linux/export.h> 220606f422SRichard Cochran #include <linux/file.h> 230606f422SRichard Cochran #include <linux/posix-clock.h> 240606f422SRichard Cochran #include <linux/slab.h> 250606f422SRichard Cochran #include <linux/syscalls.h> 260606f422SRichard Cochran #include <linux/uaccess.h> 270606f422SRichard Cochran 28bab0aae9SThomas Gleixner #include "posix-timers.h" 29bab0aae9SThomas Gleixner 300606f422SRichard Cochran static void delete_clock(struct kref *kref); 310606f422SRichard Cochran 320606f422SRichard Cochran /* 330606f422SRichard Cochran * Returns NULL if the posix_clock instance attached to 'fp' is old and stale. 340606f422SRichard Cochran */ 350606f422SRichard Cochran static struct posix_clock *get_posix_clock(struct file *fp) 360606f422SRichard Cochran { 370606f422SRichard Cochran struct posix_clock *clk = fp->private_data; 380606f422SRichard Cochran 391791f881SRichard Cochran down_read(&clk->rwsem); 400606f422SRichard Cochran 410606f422SRichard Cochran if (!clk->zombie) 420606f422SRichard Cochran return clk; 430606f422SRichard Cochran 441791f881SRichard Cochran up_read(&clk->rwsem); 450606f422SRichard Cochran 460606f422SRichard Cochran return NULL; 470606f422SRichard Cochran } 480606f422SRichard Cochran 490606f422SRichard Cochran static void put_posix_clock(struct posix_clock *clk) 500606f422SRichard Cochran { 511791f881SRichard Cochran up_read(&clk->rwsem); 520606f422SRichard Cochran } 530606f422SRichard Cochran 540606f422SRichard Cochran static ssize_t posix_clock_read(struct file *fp, char __user *buf, 550606f422SRichard Cochran size_t count, loff_t *ppos) 560606f422SRichard Cochran { 570606f422SRichard Cochran struct posix_clock *clk = get_posix_clock(fp); 580606f422SRichard Cochran int err = -EINVAL; 590606f422SRichard Cochran 600606f422SRichard Cochran if (!clk) 610606f422SRichard Cochran return -ENODEV; 620606f422SRichard Cochran 630606f422SRichard Cochran if (clk->ops.read) 640606f422SRichard Cochran err = clk->ops.read(clk, fp->f_flags, buf, count); 650606f422SRichard Cochran 660606f422SRichard Cochran put_posix_clock(clk); 670606f422SRichard Cochran 680606f422SRichard Cochran return err; 690606f422SRichard Cochran } 700606f422SRichard Cochran 719dd95748SAl Viro static __poll_t posix_clock_poll(struct file *fp, poll_table *wait) 720606f422SRichard Cochran { 730606f422SRichard Cochran struct posix_clock *clk = get_posix_clock(fp); 749dd95748SAl Viro __poll_t result = 0; 750606f422SRichard Cochran 760606f422SRichard Cochran if (!clk) 771b9f2372SRichard Cochran return POLLERR; 780606f422SRichard Cochran 790606f422SRichard Cochran if (clk->ops.poll) 800606f422SRichard Cochran result = clk->ops.poll(clk, fp, wait); 810606f422SRichard Cochran 820606f422SRichard Cochran put_posix_clock(clk); 830606f422SRichard Cochran 840606f422SRichard Cochran return result; 850606f422SRichard Cochran } 860606f422SRichard Cochran 870606f422SRichard Cochran static long posix_clock_ioctl(struct file *fp, 880606f422SRichard Cochran unsigned int cmd, unsigned long arg) 890606f422SRichard Cochran { 900606f422SRichard Cochran struct posix_clock *clk = get_posix_clock(fp); 910606f422SRichard Cochran int err = -ENOTTY; 920606f422SRichard Cochran 930606f422SRichard Cochran if (!clk) 940606f422SRichard Cochran return -ENODEV; 950606f422SRichard Cochran 960606f422SRichard Cochran if (clk->ops.ioctl) 970606f422SRichard Cochran err = clk->ops.ioctl(clk, cmd, arg); 980606f422SRichard Cochran 990606f422SRichard Cochran put_posix_clock(clk); 1000606f422SRichard Cochran 1010606f422SRichard Cochran return err; 1020606f422SRichard Cochran } 1030606f422SRichard Cochran 1040606f422SRichard Cochran #ifdef CONFIG_COMPAT 1050606f422SRichard Cochran static long posix_clock_compat_ioctl(struct file *fp, 1060606f422SRichard Cochran unsigned int cmd, unsigned long arg) 1070606f422SRichard Cochran { 1080606f422SRichard Cochran struct posix_clock *clk = get_posix_clock(fp); 1090606f422SRichard Cochran int err = -ENOTTY; 1100606f422SRichard Cochran 1110606f422SRichard Cochran if (!clk) 1120606f422SRichard Cochran return -ENODEV; 1130606f422SRichard Cochran 1140606f422SRichard Cochran if (clk->ops.ioctl) 1150606f422SRichard Cochran err = clk->ops.ioctl(clk, cmd, arg); 1160606f422SRichard Cochran 1170606f422SRichard Cochran put_posix_clock(clk); 1180606f422SRichard Cochran 1190606f422SRichard Cochran return err; 1200606f422SRichard Cochran } 1210606f422SRichard Cochran #endif 1220606f422SRichard Cochran 1230606f422SRichard Cochran static int posix_clock_open(struct inode *inode, struct file *fp) 1240606f422SRichard Cochran { 1250606f422SRichard Cochran int err; 1260606f422SRichard Cochran struct posix_clock *clk = 1270606f422SRichard Cochran container_of(inode->i_cdev, struct posix_clock, cdev); 1280606f422SRichard Cochran 1291791f881SRichard Cochran down_read(&clk->rwsem); 1300606f422SRichard Cochran 1310606f422SRichard Cochran if (clk->zombie) { 1320606f422SRichard Cochran err = -ENODEV; 1330606f422SRichard Cochran goto out; 1340606f422SRichard Cochran } 1350606f422SRichard Cochran if (clk->ops.open) 1360606f422SRichard Cochran err = clk->ops.open(clk, fp->f_mode); 1370606f422SRichard Cochran else 1380606f422SRichard Cochran err = 0; 1390606f422SRichard Cochran 1400606f422SRichard Cochran if (!err) { 1410606f422SRichard Cochran kref_get(&clk->kref); 1420606f422SRichard Cochran fp->private_data = clk; 1430606f422SRichard Cochran } 1440606f422SRichard Cochran out: 1451791f881SRichard Cochran up_read(&clk->rwsem); 1460606f422SRichard Cochran return err; 1470606f422SRichard Cochran } 1480606f422SRichard Cochran 1490606f422SRichard Cochran static int posix_clock_release(struct inode *inode, struct file *fp) 1500606f422SRichard Cochran { 1510606f422SRichard Cochran struct posix_clock *clk = fp->private_data; 1520606f422SRichard Cochran int err = 0; 1530606f422SRichard Cochran 1540606f422SRichard Cochran if (clk->ops.release) 1550606f422SRichard Cochran err = clk->ops.release(clk); 1560606f422SRichard Cochran 1570606f422SRichard Cochran kref_put(&clk->kref, delete_clock); 1580606f422SRichard Cochran 1590606f422SRichard Cochran fp->private_data = NULL; 1600606f422SRichard Cochran 1610606f422SRichard Cochran return err; 1620606f422SRichard Cochran } 1630606f422SRichard Cochran 1640606f422SRichard Cochran static const struct file_operations posix_clock_file_operations = { 1650606f422SRichard Cochran .owner = THIS_MODULE, 1660606f422SRichard Cochran .llseek = no_llseek, 1670606f422SRichard Cochran .read = posix_clock_read, 1680606f422SRichard Cochran .poll = posix_clock_poll, 1690606f422SRichard Cochran .unlocked_ioctl = posix_clock_ioctl, 1700606f422SRichard Cochran .open = posix_clock_open, 1710606f422SRichard Cochran .release = posix_clock_release, 1720606f422SRichard Cochran #ifdef CONFIG_COMPAT 1730606f422SRichard Cochran .compat_ioctl = posix_clock_compat_ioctl, 1740606f422SRichard Cochran #endif 1750606f422SRichard Cochran }; 1760606f422SRichard Cochran 1770606f422SRichard Cochran int posix_clock_register(struct posix_clock *clk, dev_t devid) 1780606f422SRichard Cochran { 1790606f422SRichard Cochran int err; 1800606f422SRichard Cochran 1810606f422SRichard Cochran kref_init(&clk->kref); 1821791f881SRichard Cochran init_rwsem(&clk->rwsem); 1830606f422SRichard Cochran 1840606f422SRichard Cochran cdev_init(&clk->cdev, &posix_clock_file_operations); 1850606f422SRichard Cochran clk->cdev.owner = clk->ops.owner; 1860606f422SRichard Cochran err = cdev_add(&clk->cdev, devid, 1); 1870606f422SRichard Cochran 1880606f422SRichard Cochran return err; 1890606f422SRichard Cochran } 1900606f422SRichard Cochran EXPORT_SYMBOL_GPL(posix_clock_register); 1910606f422SRichard Cochran 1920606f422SRichard Cochran static void delete_clock(struct kref *kref) 1930606f422SRichard Cochran { 1940606f422SRichard Cochran struct posix_clock *clk = container_of(kref, struct posix_clock, kref); 1951791f881SRichard Cochran 1960606f422SRichard Cochran if (clk->release) 1970606f422SRichard Cochran clk->release(clk); 1980606f422SRichard Cochran } 1990606f422SRichard Cochran 2000606f422SRichard Cochran void posix_clock_unregister(struct posix_clock *clk) 2010606f422SRichard Cochran { 2020606f422SRichard Cochran cdev_del(&clk->cdev); 2030606f422SRichard Cochran 2041791f881SRichard Cochran down_write(&clk->rwsem); 2050606f422SRichard Cochran clk->zombie = true; 2061791f881SRichard Cochran up_write(&clk->rwsem); 2070606f422SRichard Cochran 2080606f422SRichard Cochran kref_put(&clk->kref, delete_clock); 2090606f422SRichard Cochran } 2100606f422SRichard Cochran EXPORT_SYMBOL_GPL(posix_clock_unregister); 2110606f422SRichard Cochran 2120606f422SRichard Cochran struct posix_clock_desc { 2130606f422SRichard Cochran struct file *fp; 2140606f422SRichard Cochran struct posix_clock *clk; 2150606f422SRichard Cochran }; 2160606f422SRichard Cochran 2170606f422SRichard Cochran static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd) 2180606f422SRichard Cochran { 2190606f422SRichard Cochran struct file *fp = fget(CLOCKID_TO_FD(id)); 2200606f422SRichard Cochran int err = -EINVAL; 2210606f422SRichard Cochran 2220606f422SRichard Cochran if (!fp) 2230606f422SRichard Cochran return err; 2240606f422SRichard Cochran 2250606f422SRichard Cochran if (fp->f_op->open != posix_clock_open || !fp->private_data) 2260606f422SRichard Cochran goto out; 2270606f422SRichard Cochran 2280606f422SRichard Cochran cd->fp = fp; 2290606f422SRichard Cochran cd->clk = get_posix_clock(fp); 2300606f422SRichard Cochran 2310606f422SRichard Cochran err = cd->clk ? 0 : -ENODEV; 2320606f422SRichard Cochran out: 2330606f422SRichard Cochran if (err) 2340606f422SRichard Cochran fput(fp); 2350606f422SRichard Cochran return err; 2360606f422SRichard Cochran } 2370606f422SRichard Cochran 2380606f422SRichard Cochran static void put_clock_desc(struct posix_clock_desc *cd) 2390606f422SRichard Cochran { 2400606f422SRichard Cochran put_posix_clock(cd->clk); 2410606f422SRichard Cochran fput(cd->fp); 2420606f422SRichard Cochran } 2430606f422SRichard Cochran 2440606f422SRichard Cochran static int pc_clock_adjtime(clockid_t id, struct timex *tx) 2450606f422SRichard Cochran { 2460606f422SRichard Cochran struct posix_clock_desc cd; 2470606f422SRichard Cochran int err; 2480606f422SRichard Cochran 2490606f422SRichard Cochran err = get_clock_desc(id, &cd); 2500606f422SRichard Cochran if (err) 2510606f422SRichard Cochran return err; 2520606f422SRichard Cochran 2536e6823d1STorben Hohn if ((cd.fp->f_mode & FMODE_WRITE) == 0) { 2546e6823d1STorben Hohn err = -EACCES; 2556e6823d1STorben Hohn goto out; 2566e6823d1STorben Hohn } 2576e6823d1STorben Hohn 2580606f422SRichard Cochran if (cd.clk->ops.clock_adjtime) 2590606f422SRichard Cochran err = cd.clk->ops.clock_adjtime(cd.clk, tx); 2600606f422SRichard Cochran else 2610606f422SRichard Cochran err = -EOPNOTSUPP; 2626e6823d1STorben Hohn out: 2630606f422SRichard Cochran put_clock_desc(&cd); 2640606f422SRichard Cochran 2650606f422SRichard Cochran return err; 2660606f422SRichard Cochran } 2670606f422SRichard Cochran 2683c9c12f4SDeepa Dinamani static int pc_clock_gettime(clockid_t id, struct timespec64 *ts) 2690606f422SRichard Cochran { 2700606f422SRichard Cochran struct posix_clock_desc cd; 2710606f422SRichard Cochran int err; 2720606f422SRichard Cochran 2730606f422SRichard Cochran err = get_clock_desc(id, &cd); 2740606f422SRichard Cochran if (err) 2750606f422SRichard Cochran return err; 2760606f422SRichard Cochran 2773c9c12f4SDeepa Dinamani if (cd.clk->ops.clock_gettime) 2783c9c12f4SDeepa Dinamani err = cd.clk->ops.clock_gettime(cd.clk, ts); 2790606f422SRichard Cochran else 2800606f422SRichard Cochran err = -EOPNOTSUPP; 2810606f422SRichard Cochran 2820606f422SRichard Cochran put_clock_desc(&cd); 2830606f422SRichard Cochran 2840606f422SRichard Cochran return err; 2850606f422SRichard Cochran } 2860606f422SRichard Cochran 287d2e3e0caSDeepa Dinamani static int pc_clock_getres(clockid_t id, struct timespec64 *ts) 2880606f422SRichard Cochran { 2890606f422SRichard Cochran struct posix_clock_desc cd; 2900606f422SRichard Cochran int err; 2910606f422SRichard Cochran 2920606f422SRichard Cochran err = get_clock_desc(id, &cd); 2930606f422SRichard Cochran if (err) 2940606f422SRichard Cochran return err; 2950606f422SRichard Cochran 296d2e3e0caSDeepa Dinamani if (cd.clk->ops.clock_getres) 297d2e3e0caSDeepa Dinamani err = cd.clk->ops.clock_getres(cd.clk, ts); 2980606f422SRichard Cochran else 2990606f422SRichard Cochran err = -EOPNOTSUPP; 3000606f422SRichard Cochran 3010606f422SRichard Cochran put_clock_desc(&cd); 3020606f422SRichard Cochran 3030606f422SRichard Cochran return err; 3040606f422SRichard Cochran } 3050606f422SRichard Cochran 3060fe6afe3SDeepa Dinamani static int pc_clock_settime(clockid_t id, const struct timespec64 *ts) 3070606f422SRichard Cochran { 3080606f422SRichard Cochran struct posix_clock_desc cd; 3090606f422SRichard Cochran int err; 3100606f422SRichard Cochran 3110606f422SRichard Cochran err = get_clock_desc(id, &cd); 3120606f422SRichard Cochran if (err) 3130606f422SRichard Cochran return err; 3140606f422SRichard Cochran 3156e6823d1STorben Hohn if ((cd.fp->f_mode & FMODE_WRITE) == 0) { 3166e6823d1STorben Hohn err = -EACCES; 3176e6823d1STorben Hohn goto out; 3186e6823d1STorben Hohn } 3196e6823d1STorben Hohn 3200606f422SRichard Cochran if (cd.clk->ops.clock_settime) 3210fe6afe3SDeepa Dinamani err = cd.clk->ops.clock_settime(cd.clk, ts); 3220606f422SRichard Cochran else 3230606f422SRichard Cochran err = -EOPNOTSUPP; 3246e6823d1STorben Hohn out: 3250606f422SRichard Cochran put_clock_desc(&cd); 3260606f422SRichard Cochran 3270606f422SRichard Cochran return err; 3280606f422SRichard Cochran } 3290606f422SRichard Cochran 330d3ba5a9aSChristoph Hellwig const struct k_clock clock_posix_dynamic = { 3310606f422SRichard Cochran .clock_getres = pc_clock_getres, 3320606f422SRichard Cochran .clock_set = pc_clock_settime, 3330606f422SRichard Cochran .clock_get = pc_clock_gettime, 3340606f422SRichard Cochran .clock_adj = pc_clock_adjtime, 3350606f422SRichard Cochran }; 336