// SPDX-License-Identifier: GPL-2.0+ /* * Support for dynamic clock devices * * Copyright (C) 2010 OMICRON electronics GmbH */ #include #include #include #include #include #include #include #include "posix-timers.h" /* * Returns NULL if the posix_clock instance attached to 'fp' is old and stale. */ static struct posix_clock *get_posix_clock(struct file *fp) { struct posix_clock_context *pccontext = fp->private_data; struct posix_clock *clk = pccontext->clk; down_read(&clk->rwsem); if (!clk->zombie) return clk; up_read(&clk->rwsem); return NULL; } static void put_posix_clock(struct posix_clock *clk) { up_read(&clk->rwsem); } static ssize_t posix_clock_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos) { struct posix_clock_context *pccontext = fp->private_data; struct posix_clock *clk = get_posix_clock(fp); int err = -EINVAL; if (!clk) return -ENODEV; if (clk->ops.read) err = clk->ops.read(pccontext, fp->f_flags, buf, count); put_posix_clock(clk); return err; } static __poll_t posix_clock_poll(struct file *fp, poll_table *wait) { struct posix_clock_context *pccontext = fp->private_data; struct posix_clock *clk = get_posix_clock(fp); __poll_t result = 0; if (!clk) return EPOLLERR; if (clk->ops.poll) result = clk->ops.poll(pccontext, fp, wait); put_posix_clock(clk); return result; } static long posix_clock_ioctl(struct file *fp, unsigned int cmd, unsigned long arg) { struct posix_clock_context *pccontext = fp->private_data; struct posix_clock *clk = get_posix_clock(fp); int err = -ENOTTY; if (!clk) return -ENODEV; if (clk->ops.ioctl) err = clk->ops.ioctl(pccontext, cmd, arg); put_posix_clock(clk); return err; } #ifdef CONFIG_COMPAT static long posix_clock_compat_ioctl(struct file *fp, unsigned int cmd, unsigned long arg) { struct posix_clock_context *pccontext = fp->private_data; struct posix_clock *clk = get_posix_clock(fp); int err = -ENOTTY; if (!clk) return -ENODEV; if (clk->ops.ioctl) err = clk->ops.ioctl(pccontext, cmd, arg); put_posix_clock(clk); return err; } #endif static int posix_clock_open(struct inode *inode, struct file *fp) { int err; struct posix_clock *clk = container_of(inode->i_cdev, struct posix_clock, cdev); struct posix_clock_context *pccontext; down_read(&clk->rwsem); if (clk->zombie) { err = -ENODEV; goto out; } pccontext = kzalloc(sizeof(*pccontext), GFP_KERNEL); if (!pccontext) { err = -ENOMEM; goto out; } pccontext->clk = clk; fp->private_data = pccontext; if (clk->ops.open) err = clk->ops.open(pccontext, fp->f_mode); else err = 0; if (!err) { get_device(clk->dev); } out: up_read(&clk->rwsem); return err; } static int posix_clock_release(struct inode *inode, struct file *fp) { struct posix_clock_context *pccontext = fp->private_data; struct posix_clock *clk; int err = 0; if (!pccontext) return -ENODEV; clk = pccontext->clk; if (clk->ops.release) err = clk->ops.release(pccontext); put_device(clk->dev); kfree(pccontext); fp->private_data = NULL; return err; } static const struct file_operations posix_clock_file_operations = { .owner = THIS_MODULE, .llseek = no_llseek, .read = posix_clock_read, .poll = posix_clock_poll, .unlocked_ioctl = posix_clock_ioctl, .open = posix_clock_open, .release = posix_clock_release, #ifdef CONFIG_COMPAT .compat_ioctl = posix_clock_compat_ioctl, #endif }; int posix_clock_register(struct posix_clock *clk, struct device *dev) { int err; init_rwsem(&clk->rwsem); cdev_init(&clk->cdev, &posix_clock_file_operations); err = cdev_device_add(&clk->cdev, dev); if (err) { pr_err("%s unable to add device %d:%d\n", dev_name(dev), MAJOR(dev->devt), MINOR(dev->devt)); return err; } clk->cdev.owner = clk->ops.owner; clk->dev = dev; return 0; } EXPORT_SYMBOL_GPL(posix_clock_register); void posix_clock_unregister(struct posix_clock *clk) { cdev_device_del(&clk->cdev, clk->dev); down_write(&clk->rwsem); clk->zombie = true; up_write(&clk->rwsem); put_device(clk->dev); } EXPORT_SYMBOL_GPL(posix_clock_unregister); struct posix_clock_desc { struct file *fp; struct posix_clock *clk; }; static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd) { struct file *fp = fget(clockid_to_fd(id)); int err = -EINVAL; if (!fp) return err; if (fp->f_op->open != posix_clock_open || !fp->private_data) goto out; cd->fp = fp; cd->clk = get_posix_clock(fp); err = cd->clk ? 0 : -ENODEV; out: if (err) fput(fp); return err; } static void put_clock_desc(struct posix_clock_desc *cd) { put_posix_clock(cd->clk); fput(cd->fp); } static int pc_clock_adjtime(clockid_t id, struct __kernel_timex *tx) { struct posix_clock_desc cd; int err; err = get_clock_desc(id, &cd); if (err) return err; if ((cd.fp->f_mode & FMODE_WRITE) == 0) { err = -EACCES; goto out; } if (cd.clk->ops.clock_adjtime) err = cd.clk->ops.clock_adjtime(cd.clk, tx); else err = -EOPNOTSUPP; out: put_clock_desc(&cd); return err; } static int pc_clock_gettime(clockid_t id, struct timespec64 *ts) { struct posix_clock_desc cd; int err; err = get_clock_desc(id, &cd); if (err) return err; if (cd.clk->ops.clock_gettime) err = cd.clk->ops.clock_gettime(cd.clk, ts); else err = -EOPNOTSUPP; put_clock_desc(&cd); return err; } static int pc_clock_getres(clockid_t id, struct timespec64 *ts) { struct posix_clock_desc cd; int err; err = get_clock_desc(id, &cd); if (err) return err; if (cd.clk->ops.clock_getres) err = cd.clk->ops.clock_getres(cd.clk, ts); else err = -EOPNOTSUPP; put_clock_desc(&cd); return err; } static int pc_clock_settime(clockid_t id, const struct timespec64 *ts) { struct posix_clock_desc cd; int err; err = get_clock_desc(id, &cd); if (err) return err; if ((cd.fp->f_mode & FMODE_WRITE) == 0) { err = -EACCES; goto out; } if (cd.clk->ops.clock_settime) err = cd.clk->ops.clock_settime(cd.clk, ts); else err = -EOPNOTSUPP; out: put_clock_desc(&cd); return err; } const struct k_clock clock_posix_dynamic = { .clock_getres = pc_clock_getres, .clock_set = pc_clock_settime, .clock_get_timespec = pc_clock_gettime, .clock_adj = pc_clock_adjtime, };