d94ba80ebb
This patch adds an infrastructure for hardware clocks that implement IEEE 1588, the Precision Time Protocol (PTP). A class driver offers a registration method to particular hardware clock drivers. Each clock is presented as a standard POSIX clock. The ancillary clock features are exposed in two different ways, via the sysfs and by a character device. Signed-off-by: Richard Cochran <richard.cochran@omicron.at> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: John Stultz <john.stultz@linaro.org>
93 lines
2.6 KiB
C
93 lines
2.6 KiB
C
/*
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* PTP 1588 clock support - private declarations for the core module.
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*
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* Copyright (C) 2010 OMICRON electronics GmbH
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifndef _PTP_PRIVATE_H_
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#define _PTP_PRIVATE_H_
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#include <linux/cdev.h>
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#include <linux/device.h>
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#include <linux/mutex.h>
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#include <linux/posix-clock.h>
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#include <linux/ptp_clock.h>
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#include <linux/ptp_clock_kernel.h>
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#include <linux/time.h>
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#define PTP_MAX_TIMESTAMPS 128
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#define PTP_BUF_TIMESTAMPS 30
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struct timestamp_event_queue {
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struct ptp_extts_event buf[PTP_MAX_TIMESTAMPS];
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int head;
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int tail;
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spinlock_t lock;
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};
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struct ptp_clock {
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struct posix_clock clock;
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struct device *dev;
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struct ptp_clock_info *info;
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dev_t devid;
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int index; /* index into clocks.map */
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struct pps_device *pps_source;
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struct timestamp_event_queue tsevq; /* simple fifo for time stamps */
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struct mutex tsevq_mux; /* one process at a time reading the fifo */
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wait_queue_head_t tsev_wq;
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int defunct; /* tells readers to go away when clock is being removed */
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};
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/*
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* The function queue_cnt() is safe for readers to call without
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* holding q->lock. Readers use this function to verify that the queue
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* is nonempty before proceeding with a dequeue operation. The fact
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* that a writer might concurrently increment the tail does not
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* matter, since the queue remains nonempty nonetheless.
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*/
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static inline int queue_cnt(struct timestamp_event_queue *q)
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{
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int cnt = q->tail - q->head;
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return cnt < 0 ? PTP_MAX_TIMESTAMPS + cnt : cnt;
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}
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/*
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* see ptp_chardev.c
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*/
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long ptp_ioctl(struct posix_clock *pc,
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unsigned int cmd, unsigned long arg);
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int ptp_open(struct posix_clock *pc, fmode_t fmode);
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ssize_t ptp_read(struct posix_clock *pc,
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uint flags, char __user *buf, size_t cnt);
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uint ptp_poll(struct posix_clock *pc,
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struct file *fp, poll_table *wait);
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/*
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* see ptp_sysfs.c
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*/
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extern struct device_attribute ptp_dev_attrs[];
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int ptp_cleanup_sysfs(struct ptp_clock *ptp);
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int ptp_populate_sysfs(struct ptp_clock *ptp);
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#endif
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