drivers/ptp/ptp_private.h

   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
  34 struct timestamp_event_queue {
  35         struct ptp_extts_event buf[PTP_MAX_TIMESTAMPS];
  36         int head;
  37         int tail;
  38         spinlock_t lock;
  39 };
  40
  41 struct 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         long dialed_frequency; /* remembers the frequency adjustment */
  49         struct timestamp_event_queue tsevq; /* simple fifo for time stamps */
  50         struct mutex tsevq_mux; /* one process at a time reading the fifo */
  51         wait_queue_head_t tsev_wq;
  52         int defunct; /* tells readers to go away when clock is being removed */
  53 };
  54
  55 /*
  56  * The function queue_cnt() is safe for readers to call without
  57  * holding q->lock. Readers use this function to verify that the queue
  58  * is nonempty before proceeding with a dequeue operation. The fact
  59  * that a writer might concurrently increment the tail does not
  60  * matter, since the queue remains nonempty nonetheless.
  61  */
  62 static inline int queue_cnt(struct timestamp_event_queue *q)
  63 {
  64         int cnt = q->tail - q->head;
  65         return cnt < 0 ? PTP_MAX_TIMESTAMPS + cnt : cnt;
  66 }
  67
  68 /*
  69  * see ptp_chardev.c
  70  */
  71
  72 long ptp_ioctl(struct posix_clock *pc,
  73                unsigned int cmd, unsigned long arg);
  74
  75 int ptp_open(struct posix_clock *pc, fmode_t fmode);
  76
  77 ssize_t ptp_read(struct posix_clock *pc,
  78                  uint flags, char __user *buf, size_t cnt);
  79
  80 uint ptp_poll(struct posix_clock *pc,
  81               struct file *fp, poll_table *wait);
  82
  83 /*
  84  * see ptp_sysfs.c
  85  */
  86
  87 extern struct device_attribute ptp_dev_attrs[];
  88
  89 int ptp_cleanup_sysfs(struct ptp_clock *ptp);
  90
  91 int ptp_populate_sysfs(struct ptp_clock *ptp);
  92
  93 #endif