5 files changed, 601 insertions, 3 deletions

diff --git a/include/linux/posix-clock.h b/include/linux/posix-clock.h
new file mode 100644
index 000000000000..369e19d3750b
--- /dev/null
+++ b/include/linux/posix-clock.h
@@ -0,0 +1,150 @@
+/*
+ * 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
diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index 9d6ffe2c92e5..d51243ae0726 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -32,7 +32,7 @@ struct cpu_timer_list {
 #define CPUCLOCK_PID(clock)             ((pid_t) ~((clock) >> 3))
 #define CPUCLOCK_PERTHREAD(clock) \
         (((clock) & (clockid_t) CPUCLOCK_PERTHREAD_MASK) != 0)
-#define CPUCLOCK_PID_MASK       7
+
 #define CPUCLOCK_PERTHREAD_MASK 4
 #define CPUCLOCK_WHICH(clock)   ((clock) & (clockid_t) CPUCLOCK_CLOCK_MASK)
 #define CPUCLOCK_CLOCK_MASK     3
@@ -48,6 +48,9 @@ struct cpu_timer_list {
 #define MAKE_THREAD_CPUCLOCK(tid, clock) \
         MAKE_PROCESS_CPUCLOCK((tid), (clock) | CPUCLOCK_PERTHREAD_MASK)
 
+#define FD_TO_CLOCKID(fd)       ((~(clockid_t) (fd) << 3) | CLOCKFD)
+#define CLOCKID_TO_FD(clk)      ((unsigned int) ~((clk) >> 3))
+
 /* POSIX.1b interval timer structure. */
 struct k_itimer {
         struct list_head list;          /* free/ allocate list */
@@ -100,6 +103,7 @@ struct k_clock {
 };
 
 extern struct k_clock clock_posix_cpu;
+extern struct k_clock clock_posix_dynamic;
 
 void posix_timers_register_clock(const clockid_t clock_id, struct k_clock *new_clock);
 
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index af936fd37140..44fcff131b38 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -41,6 +41,7 @@
 #include <linux/init.h>
 #include <linux/compiler.h>
 #include <linux/idr.h>
+#include <linux/posix-clock.h>
 #include <linux/posix-timers.h>
 #include <linux/syscalls.h>
 #include <linux/wait.h>
@@ -489,7 +490,8 @@ static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
 static struct k_clock *clockid_to_kclock(const clockid_t id)
 {
         if (id < 0)
-                return (id & CLOCKFD_MASK) == CLOCKFD ? NULL : &clock_posix_cpu;
+                return (id & CLOCKFD_MASK) == CLOCKFD ?
+                        &clock_posix_dynamic : &clock_posix_cpu;
 
         if (id >= MAX_CLOCKS || !posix_clocks[id].clock_getres)
                 return NULL;
diff --git a/kernel/time/Makefile b/kernel/time/Makefile
index ee266620b06c..b0425991e9ac 100644
--- a/kernel/time/Makefile
+++ b/kernel/time/Makefile
@@ -1,4 +1,5 @@
-obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o timecompare.o timeconv.o
+obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o timecompare.o
+obj-y += timeconv.o posix-clock.o
 
 obj-$(CONFIG_GENERIC_CLOCKEVENTS_BUILD)         += clockevents.o
 obj-$(CONFIG_GENERIC_CLOCKEVENTS)               += tick-common.o
diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c
new file mode 100644
index 000000000000..04498cbf6002
--- /dev/null
+++ b/kernel/time/posix-clock.c
@@ -0,0 +1,441 @@
+/*
+ * 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,
+};