--- /dev/null
+/*
+ * posix-clock.h - support for dynamic clock devices
+ *
+ * Copyright (C) 2010 OMICRON electronics GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#ifndef _LINUX_POSIX_CLOCK_H_
+#define _LINUX_POSIX_CLOCK_H_
+
+#include <linux/cdev.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/posix-timers.h>
+
+struct posix_clock;
+
+/**
+ * struct posix_clock_operations - functional interface to the clock
+ *
+ * Every posix clock is represented by a character device. Drivers may
+ * optionally offer extended capabilities by implementing the
+ * character device methods. The character device file operations are
+ * first handled by the clock device layer, then passed on to the
+ * driver by calling these functions.
+ *
+ * @owner: The clock driver should set to THIS_MODULE
+ * @clock_adjtime: Adjust the clock
+ * @clock_gettime: Read the current time
+ * @clock_getres: Get the clock resolution
+ * @clock_settime: Set the current time value
+ * @timer_create: Create a new timer
+ * @timer_delete: Remove a previously created timer
+ * @timer_gettime: Get remaining time and interval of a timer
+ * @timer_setttime: Set a timer's initial expiration and interval
+ * @fasync: Optional character device fasync method
+ * @mmap: Optional character device mmap method
+ * @open: Optional character device open method
+ * @release: Optional character device release method
+ * @ioctl: Optional character device ioctl method
+ * @read: Optional character device read method
+ * @poll: Optional character device poll method
+ */
+struct posix_clock_operations {
+ struct module *owner;
+
+ int (*clock_adjtime)(struct posix_clock *pc, struct timex *tx);
+
+ int (*clock_gettime)(struct posix_clock *pc, struct timespec *ts);
+
+ int (*clock_getres) (struct posix_clock *pc, struct timespec *ts);
+
+ int (*clock_settime)(struct posix_clock *pc,
+ const struct timespec *ts);
+
+ int (*timer_create) (struct posix_clock *pc, struct k_itimer *kit);
+
+ int (*timer_delete) (struct posix_clock *pc, struct k_itimer *kit);
+
+ void (*timer_gettime)(struct posix_clock *pc,
+ struct k_itimer *kit, struct itimerspec *tsp);
+
+ int (*timer_settime)(struct posix_clock *pc,
+ struct k_itimer *kit, int flags,
+ struct itimerspec *tsp, struct itimerspec *old);
+ /*
+ * Optional character device methods:
+ */
+ int (*fasync) (struct posix_clock *pc,
+ int fd, struct file *file, int on);
+
+ long (*ioctl) (struct posix_clock *pc,
+ unsigned int cmd, unsigned long arg);
+
+ int (*mmap) (struct posix_clock *pc,
+ struct vm_area_struct *vma);
+
+ int (*open) (struct posix_clock *pc, fmode_t f_mode);
+
+ uint (*poll) (struct posix_clock *pc,
+ struct file *file, poll_table *wait);
+
+ int (*release) (struct posix_clock *pc);
+
+ ssize_t (*read) (struct posix_clock *pc,
+ uint flags, char __user *buf, size_t cnt);
+};
+
+/**
+ * struct posix_clock - represents a dynamic posix clock
+ *
+ * @ops: Functional interface to the clock
+ * @cdev: Character device instance for this clock
+ * @kref: Reference count.
+ * @mutex: Protects the 'zombie' field from concurrent access.
+ * @zombie: If 'zombie' is true, then the hardware has disappeared.
+ * @release: A function to free the structure when the reference count reaches
+ * zero. May be NULL if structure is statically allocated.
+ *
+ * Drivers should embed their struct posix_clock within a private
+ * structure, obtaining a reference to it during callbacks using
+ * container_of().
+ */
+struct posix_clock {
+ struct posix_clock_operations ops;
+ struct cdev cdev;
+ struct kref kref;
+ struct mutex mutex;
+ bool zombie;
+ void (*release)(struct posix_clock *clk);
+};
+
+/**
+ * posix_clock_register() - register a new clock
+ * @clk: Pointer to the clock. Caller must provide 'ops' and 'release'
+ * @devid: Allocated device id
+ *
+ * A clock driver calls this function to register itself with the
+ * clock device subsystem. If 'clk' points to dynamically allocated
+ * memory, then the caller must provide a 'release' function to free
+ * that memory.
+ *
+ * Returns zero on success, non-zero otherwise.
+ */
+int posix_clock_register(struct posix_clock *clk, dev_t devid);
+
+/**
+ * posix_clock_unregister() - unregister a clock
+ * @clk: Clock instance previously registered via posix_clock_register()
+ *
+ * A clock driver calls this function to remove itself from the clock
+ * device subsystem. The posix_clock itself will remain (in an
+ * inactive state) until its reference count drops to zero, at which
+ * point it will be deallocated with its 'release' method.
+ */
+void posix_clock_unregister(struct posix_clock *clk);
+
+#endif
--- /dev/null
+/*
+ * posix-clock.c - support for dynamic clock devices
+ *
+ * Copyright (C) 2010 OMICRON electronics GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <linux/device.h>
+#include <linux/file.h>
+#include <linux/mutex.h>
+#include <linux/posix-clock.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/uaccess.h>
+
+static void delete_clock(struct kref *kref);
+
+/*
+ * 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 *clk = fp->private_data;
+
+ mutex_lock(&clk->mutex);
+
+ if (!clk->zombie)
+ return clk;
+
+ mutex_unlock(&clk->mutex);
+
+ return NULL;
+}
+
+static void put_posix_clock(struct posix_clock *clk)
+{
+ mutex_unlock(&clk->mutex);
+}
+
+static ssize_t posix_clock_read(struct file *fp, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int err = -EINVAL;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.read)
+ err = clk->ops.read(clk, fp->f_flags, buf, count);
+
+ put_posix_clock(clk);
+
+ return err;
+}
+
+static unsigned int posix_clock_poll(struct file *fp, poll_table *wait)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int result = 0;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.poll)
+ result = clk->ops.poll(clk, fp, wait);
+
+ put_posix_clock(clk);
+
+ return result;
+}
+
+static int posix_clock_fasync(int fd, struct file *fp, int on)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int err = 0;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.fasync)
+ err = clk->ops.fasync(clk, fd, fp, on);
+
+ put_posix_clock(clk);
+
+ return err;
+}
+
+static int posix_clock_mmap(struct file *fp, struct vm_area_struct *vma)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int err = -ENODEV;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.mmap)
+ err = clk->ops.mmap(clk, vma);
+
+ put_posix_clock(clk);
+
+ return err;
+}
+
+static long posix_clock_ioctl(struct file *fp,
+ unsigned int cmd, unsigned long arg)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int err = -ENOTTY;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.ioctl)
+ err = clk->ops.ioctl(clk, 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 *clk = get_posix_clock(fp);
+ int err = -ENOTTY;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.ioctl)
+ err = clk->ops.ioctl(clk, 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);
+
+ mutex_lock(&clk->mutex);
+
+ if (clk->zombie) {
+ err = -ENODEV;
+ goto out;
+ }
+ if (clk->ops.open)
+ err = clk->ops.open(clk, fp->f_mode);
+ else
+ err = 0;
+
+ if (!err) {
+ kref_get(&clk->kref);
+ fp->private_data = clk;
+ }
+out:
+ mutex_unlock(&clk->mutex);
+ return err;
+}
+
+static int posix_clock_release(struct inode *inode, struct file *fp)
+{
+ struct posix_clock *clk = fp->private_data;
+ int err = 0;
+
+ if (clk->ops.release)
+ err = clk->ops.release(clk);
+
+ kref_put(&clk->kref, delete_clock);
+
+ 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,
+ .fasync = posix_clock_fasync,
+ .mmap = posix_clock_mmap,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = posix_clock_compat_ioctl,
+#endif
+};
+
+int posix_clock_register(struct posix_clock *clk, dev_t devid)
+{
+ int err;
+
+ kref_init(&clk->kref);
+ mutex_init(&clk->mutex);
+
+ cdev_init(&clk->cdev, &posix_clock_file_operations);
+ clk->cdev.owner = clk->ops.owner;
+ err = cdev_add(&clk->cdev, devid, 1);
+ if (err)
+ goto no_cdev;
+
+ return err;
+no_cdev:
+ mutex_destroy(&clk->mutex);
+ return err;
+}
+EXPORT_SYMBOL_GPL(posix_clock_register);
+
+static void delete_clock(struct kref *kref)
+{
+ struct posix_clock *clk = container_of(kref, struct posix_clock, kref);
+ mutex_destroy(&clk->mutex);
+ if (clk->release)
+ clk->release(clk);
+}
+
+void posix_clock_unregister(struct posix_clock *clk)
+{
+ cdev_del(&clk->cdev);
+
+ mutex_lock(&clk->mutex);
+ clk->zombie = true;
+ mutex_unlock(&clk->mutex);
+
+ kref_put(&clk->kref, delete_clock);
+}
+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 timex *tx)
+{
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.clock_adjtime)
+ err = cd.clk->ops.clock_adjtime(cd.clk, tx);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static int pc_clock_gettime(clockid_t id, struct timespec *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 timespec *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 timespec *ts)
+{
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.clock_settime)
+ err = cd.clk->ops.clock_settime(cd.clk, ts);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static int pc_timer_create(struct k_itimer *kit)
+{
+ clockid_t id = kit->it_clock;
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.timer_create)
+ err = cd.clk->ops.timer_create(cd.clk, kit);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static int pc_timer_delete(struct k_itimer *kit)
+{
+ clockid_t id = kit->it_clock;
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.timer_delete)
+ err = cd.clk->ops.timer_delete(cd.clk, kit);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static void pc_timer_gettime(struct k_itimer *kit, struct itimerspec *ts)
+{
+ clockid_t id = kit->it_clock;
+ struct posix_clock_desc cd;
+
+ if (get_clock_desc(id, &cd))
+ return;
+
+ if (cd.clk->ops.timer_gettime)
+ cd.clk->ops.timer_gettime(cd.clk, kit, ts);
+
+ put_clock_desc(&cd);
+}
+
+static int pc_timer_settime(struct k_itimer *kit, int flags,
+ struct itimerspec *ts, struct itimerspec *old)
+{
+ clockid_t id = kit->it_clock;
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.timer_settime)
+ err = cd.clk->ops.timer_settime(cd.clk, kit, flags, ts, old);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+struct k_clock clock_posix_dynamic = {
+ .clock_getres = pc_clock_getres,
+ .clock_set = pc_clock_settime,
+ .clock_get = pc_clock_gettime,
+ .clock_adj = pc_clock_adjtime,
+ .timer_create = pc_timer_create,
+ .timer_set = pc_timer_settime,
+ .timer_del = pc_timer_delete,
+ .timer_get = pc_timer_gettime,
+};
projects / linux-platform-drivers-x86.git / commitdiff