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r: 234618
b: refs/heads/master
c: 0606f42
h: refs/heads/master
v: v3
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Richard Cochran authored and Thomas Gleixner committed Feb 2, 2011
1 parent 1da76d2 commit 9744043
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Showing 6 changed files with 602 additions and 4 deletions.
2 changes: 1 addition & 1 deletion [refs]
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---
refs/heads/master: 527087374faa488776a789375a7d6ea74fda6f71
refs/heads/master: 0606f422b453f76c31ab2b1bd52943ff06a2dcf2
150 changes: 150 additions & 0 deletions trunk/include/linux/posix-clock.h
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/*
* 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
6 changes: 5 additions & 1 deletion trunk/include/linux/posix-timers.h
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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 */
Expand Down Expand Up @@ -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);

Expand Down
4 changes: 3 additions & 1 deletion trunk/kernel/posix-timers.c
Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand Down Expand Up @@ -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;
Expand Down
3 changes: 2 additions & 1 deletion trunk/kernel/time/Makefile
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@@ -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
Expand Down
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