root/drivers/ptp/ptp_private.h

INCLUDED FROM

DEFINITIONS

1. queue_cnt

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * PTP 1588 clock support - private declarations for the core module.
   4  *
   5  * Copyright (C) 2010 OMICRON electronics GmbH
   6  */
   7 #ifndef _PTP_PRIVATE_H_
   8 #define _PTP_PRIVATE_H_
   9 
  10 #include <linux/cdev.h>
  11 #include <linux/device.h>
  12 #include <linux/kthread.h>
  13 #include <linux/mutex.h>
  14 #include <linux/posix-clock.h>
  15 #include <linux/ptp_clock.h>
  16 #include <linux/ptp_clock_kernel.h>
  17 #include <linux/time.h>
  18 
  19 #define PTP_MAX_TIMESTAMPS 128
  20 #define PTP_BUF_TIMESTAMPS 30
  21 
  22 struct timestamp_event_queue {
  23         struct ptp_extts_event buf[PTP_MAX_TIMESTAMPS];
  24         int head;
  25         int tail;
  26         spinlock_t lock;
  27 };
  28 
  29 struct ptp_clock {
  30         struct posix_clock clock;
  31         struct device dev;
  32         struct ptp_clock_info *info;
  33         dev_t devid;
  34         int index; /* index into clocks.map */
  35         struct pps_device *pps_source;
  36         long dialed_frequency; /* remembers the frequency adjustment */
  37         struct timestamp_event_queue tsevq; /* simple fifo for time stamps */
  38         struct mutex tsevq_mux; /* one process at a time reading the fifo */
  39         struct mutex pincfg_mux; /* protect concurrent info->pin_config access */
  40         wait_queue_head_t tsev_wq;
  41         int defunct; /* tells readers to go away when clock is being removed */
  42         struct device_attribute *pin_dev_attr;
  43         struct attribute **pin_attr;
  44         struct attribute_group pin_attr_group;
  45         /* 1st entry is a pointer to the real group, 2nd is NULL terminator */
  46         const struct attribute_group *pin_attr_groups[2];
  47         struct kthread_worker *kworker;
  48         struct kthread_delayed_work aux_work;
  49 };
  50 
  51 /*
  52  * The function queue_cnt() is safe for readers to call without
  53  * holding q->lock. Readers use this function to verify that the queue
  54  * is nonempty before proceeding with a dequeue operation. The fact
  55  * that a writer might concurrently increment the tail does not
  56  * matter, since the queue remains nonempty nonetheless.
  57  */
  58 static inline int queue_cnt(struct timestamp_event_queue *q)
  59 {
  60         int cnt = q->tail - q->head;
  61         return cnt < 0 ? PTP_MAX_TIMESTAMPS + cnt : cnt;
  62 }
  63 
  64 /*
  65  * see ptp_chardev.c
  66  */
  67 
  68 /* caller must hold pincfg_mux */
  69 int ptp_set_pinfunc(struct ptp_clock *ptp, unsigned int pin,
  70                     enum ptp_pin_function func, unsigned int chan);
  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 __poll_t ptp_poll(struct posix_clock *pc,
  81               struct file *fp, poll_table *wait);
  82 
  83 /*
  84  * see ptp_sysfs.c
  85  */
  86 
  87 extern const struct attribute_group *ptp_groups[];
  88 
  89 int ptp_populate_pin_groups(struct ptp_clock *ptp);
  90 void ptp_cleanup_pin_groups(struct ptp_clock *ptp);
  91 
  92 #endif