mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-16 12:56:54 +07:00
eae9d2ba0c
This patch adds the kernel side of the PPS support currently named "LinuxPPS". PPS means "pulse per second" and a PPS source is just a device which provides a high precision signal each second so that an application can use it to adjust system clock time. Common use is the combination of the NTPD as userland program with a GPS receiver as PPS source to obtain a wallclock-time with sub-millisecond synchronisation to UTC. To obtain this goal the userland programs shoud use the PPS API specification (RFC 2783 - Pulse-Per-Second API for UNIX-like Operating Systems, Version 1.0) which in part is implemented by this patch. It provides a set of chars devices, one per PPS source, which can be used to get the time signal. The RFC's functions can be implemented by accessing to these char devices. Signed-off-by: Rodolfo Giometti <giometti@linux.it> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg KH <greg@kroah.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
123 lines
3.8 KiB
C
123 lines
3.8 KiB
C
/*
|
|
* PPS API header
|
|
*
|
|
* Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it>
|
|
*
|
|
* 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 _PPS_H_
|
|
#define _PPS_H_
|
|
|
|
#define PPS_VERSION "5.3.6"
|
|
#define PPS_MAX_SOURCES 16 /* should be enough... */
|
|
|
|
/* Implementation note: the logical states ``assert'' and ``clear''
|
|
* are implemented in terms of the chip register, i.e. ``assert''
|
|
* means the bit is set. */
|
|
|
|
/*
|
|
* 3.2 New data structures
|
|
*/
|
|
|
|
#define PPS_API_VERS_1 1
|
|
#define PPS_API_VERS PPS_API_VERS_1 /* we use API version 1 */
|
|
#define PPS_MAX_NAME_LEN 32
|
|
|
|
/* 32-bit vs. 64-bit compatibility.
|
|
*
|
|
* 0n i386, the alignment of a uint64_t is only 4 bytes, while on most other
|
|
* architectures it's 8 bytes. On i386, there will be no padding between the
|
|
* two consecutive 'struct pps_ktime' members of struct pps_kinfo and struct
|
|
* pps_kparams. But on most platforms there will be padding to ensure correct
|
|
* alignment.
|
|
*
|
|
* The simple fix is probably to add an explicit padding.
|
|
* [David Woodhouse]
|
|
*/
|
|
struct pps_ktime {
|
|
__s64 sec;
|
|
__s32 nsec;
|
|
__u32 flags;
|
|
};
|
|
#define PPS_TIME_INVALID (1<<0) /* used to specify timeout==NULL */
|
|
|
|
struct pps_kinfo {
|
|
__u32 assert_sequence; /* seq. num. of assert event */
|
|
__u32 clear_sequence; /* seq. num. of clear event */
|
|
struct pps_ktime assert_tu; /* time of assert event */
|
|
struct pps_ktime clear_tu; /* time of clear event */
|
|
int current_mode; /* current mode bits */
|
|
};
|
|
|
|
struct pps_kparams {
|
|
int api_version; /* API version # */
|
|
int mode; /* mode bits */
|
|
struct pps_ktime assert_off_tu; /* offset compensation for assert */
|
|
struct pps_ktime clear_off_tu; /* offset compensation for clear */
|
|
};
|
|
|
|
/*
|
|
* 3.3 Mode bit definitions
|
|
*/
|
|
|
|
/* Device/implementation parameters */
|
|
#define PPS_CAPTUREASSERT 0x01 /* capture assert events */
|
|
#define PPS_CAPTURECLEAR 0x02 /* capture clear events */
|
|
#define PPS_CAPTUREBOTH 0x03 /* capture assert and clear events */
|
|
|
|
#define PPS_OFFSETASSERT 0x10 /* apply compensation for assert ev. */
|
|
#define PPS_OFFSETCLEAR 0x20 /* apply compensation for clear ev. */
|
|
|
|
#define PPS_CANWAIT 0x100 /* can we wait for an event? */
|
|
#define PPS_CANPOLL 0x200 /* bit reserved for future use */
|
|
|
|
/* Kernel actions */
|
|
#define PPS_ECHOASSERT 0x40 /* feed back assert event to output */
|
|
#define PPS_ECHOCLEAR 0x80 /* feed back clear event to output */
|
|
|
|
/* Timestamp formats */
|
|
#define PPS_TSFMT_TSPEC 0x1000 /* select timespec format */
|
|
#define PPS_TSFMT_NTPFP 0x2000 /* select NTP format */
|
|
|
|
/*
|
|
* 3.4.4 New functions: disciplining the kernel timebase
|
|
*/
|
|
|
|
/* Kernel consumers */
|
|
#define PPS_KC_HARDPPS 0 /* hardpps() (or equivalent) */
|
|
#define PPS_KC_HARDPPS_PLL 1 /* hardpps() constrained to
|
|
use a phase-locked loop */
|
|
#define PPS_KC_HARDPPS_FLL 2 /* hardpps() constrained to
|
|
use a frequency-locked loop */
|
|
/*
|
|
* Here begins the implementation-specific part!
|
|
*/
|
|
|
|
struct pps_fdata {
|
|
struct pps_kinfo info;
|
|
struct pps_ktime timeout;
|
|
};
|
|
|
|
#include <linux/ioctl.h>
|
|
|
|
#define PPS_GETPARAMS _IOR('p', 0xa1, struct pps_kparams *)
|
|
#define PPS_SETPARAMS _IOW('p', 0xa2, struct pps_kparams *)
|
|
#define PPS_GETCAP _IOR('p', 0xa3, int *)
|
|
#define PPS_FETCH _IOWR('p', 0xa4, struct pps_fdata *)
|
|
|
|
#endif /* _PPS_H_ */
|