linux/drivers/ptp/ptp_private.h
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   1/*
   2 * PTP 1588 clock support - private declarations for the core module.
   3 *
   4 * Copyright (C) 2010 OMICRON electronics GmbH
   5 *
   6 *  This program is free software; you can redistribute it and/or modify
   7 *  it under the terms of the GNU General Public License as published by
   8 *  the Free Software Foundation; either version 2 of the License, or
   9 *  (at your option) any later version.
  10 *
  11 *  This program is distributed in the hope that it will be useful,
  12 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 *  GNU General Public License for more details.
  15 *
  16 *  You should have received a copy of the GNU General Public License
  17 *  along with this program; if not, write to the Free Software
  18 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20#ifndef _PTP_PRIVATE_H_
  21#define _PTP_PRIVATE_H_
  22
  23#include <linux/cdev.h>
  24#include <linux/device.h>
  25#include <linux/mutex.h>
  26#include <linux/posix-clock.h>
  27#include <linux/ptp_clock.h>
  28#include <linux/ptp_clock_kernel.h>
  29#include <linux/time.h>
  30
  31#define PTP_MAX_TIMESTAMPS 128
  32#define PTP_BUF_TIMESTAMPS 30
  33
  34struct timestamp_event_queue {
  35        struct ptp_extts_event buf[PTP_MAX_TIMESTAMPS];
  36        int head;
  37        int tail;
  38        spinlock_t lock;
  39};
  40
  41struct ptp_clock {
  42        struct posix_clock clock;
  43        struct device *dev;
  44        struct ptp_clock_info *info;
  45        dev_t devid;
  46        int index; /* index into clocks.map */
  47        struct pps_device *pps_source;
  48        struct timestamp_event_queue tsevq; /* simple fifo for time stamps */
  49        struct mutex tsevq_mux; /* one process at a time reading the fifo */
  50        wait_queue_head_t tsev_wq;
  51        int defunct; /* tells readers to go away when clock is being removed */
  52};
  53
  54/*
  55 * The function queue_cnt() is safe for readers to call without
  56 * holding q->lock. Readers use this function to verify that the queue
  57 * is nonempty before proceeding with a dequeue operation. The fact
  58 * that a writer might concurrently increment the tail does not
  59 * matter, since the queue remains nonempty nonetheless.
  60 */
  61static inline int queue_cnt(struct timestamp_event_queue *q)
  62{
  63        int cnt = q->tail - q->head;
  64        return cnt < 0 ? PTP_MAX_TIMESTAMPS + cnt : cnt;
  65}
  66
  67/*
  68 * see ptp_chardev.c
  69 */
  70
  71long ptp_ioctl(struct posix_clock *pc,
  72               unsigned int cmd, unsigned long arg);
  73
  74int ptp_open(struct posix_clock *pc, fmode_t fmode);
  75
  76ssize_t ptp_read(struct posix_clock *pc,
  77                 uint flags, char __user *buf, size_t cnt);
  78
  79uint ptp_poll(struct posix_clock *pc,
  80              struct file *fp, poll_table *wait);
  81
  82/*
  83 * see ptp_sysfs.c
  84 */
  85
  86extern struct device_attribute ptp_dev_attrs[];
  87
  88int ptp_cleanup_sysfs(struct ptp_clock *ptp);
  89
  90int ptp_populate_sysfs(struct ptp_clock *ptp);
  91
  92#endif
  93
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