From eae9d2ba0cfc27a2ad9765f23efb98fb80d80234 Mon Sep 17 00:00:00 2001 From: Rodolfo Giometti Date: Wed, 17 Jun 2009 16:28:37 -0700 Subject: LinuxPPS: core support 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 Cc: David Woodhouse Cc: Greg KH Cc: Randy Dunlap Cc: Kay Sievers Acked-by: Alan Cox Cc: Michael Kerrisk Cc: Christoph Hellwig Cc: Roman Zippel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/Kbuild | 1 + include/linux/pps.h | 122 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/pps_kernel.h | 89 +++++++++++++++++++++++++++++++++ 3 files changed, 212 insertions(+) create mode 100644 include/linux/pps.h create mode 100644 include/linux/pps_kernel.h (limited to 'include/linux') diff --git a/include/linux/Kbuild b/include/linux/Kbuild index a2df7030d49d..03f22076381f 100644 --- a/include/linux/Kbuild +++ b/include/linux/Kbuild @@ -308,6 +308,7 @@ unifdef-y += pmu.h unifdef-y += poll.h unifdef-y += ppp_defs.h unifdef-y += ppp-comp.h +unifdef-y += pps.h unifdef-y += ptrace.h unifdef-y += quota.h unifdef-y += random.h diff --git a/include/linux/pps.h b/include/linux/pps.h new file mode 100644 index 000000000000..cfe5c7214ec6 --- /dev/null +++ b/include/linux/pps.h @@ -0,0 +1,122 @@ +/* + * PPS API header + * + * Copyright (C) 2005-2009 Rodolfo Giometti + * + * 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 + +#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_ */ diff --git a/include/linux/pps_kernel.h b/include/linux/pps_kernel.h new file mode 100644 index 000000000000..e0a193f830ef --- /dev/null +++ b/include/linux/pps_kernel.h @@ -0,0 +1,89 @@ +/* + * PPS API kernel header + * + * Copyright (C) 2009 Rodolfo Giometti + * + * 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. + */ + +#include + +#include +#include +#include + +/* + * Global defines + */ + +/* The specific PPS source info */ +struct pps_source_info { + char name[PPS_MAX_NAME_LEN]; /* simbolic name */ + char path[PPS_MAX_NAME_LEN]; /* path of connected device */ + int mode; /* PPS's allowed mode */ + + void (*echo)(int source, int event, void *data); /* PPS echo function */ + + struct module *owner; + struct device *dev; +}; + +/* The main struct */ +struct pps_device { + struct pps_source_info info; /* PSS source info */ + + struct pps_kparams params; /* PPS's current params */ + + __u32 assert_sequence; /* PPS' assert event seq # */ + __u32 clear_sequence; /* PPS' clear event seq # */ + struct pps_ktime assert_tu; + struct pps_ktime clear_tu; + int current_mode; /* PPS mode at event time */ + + int go; /* PPS event is arrived? */ + wait_queue_head_t queue; /* PPS event queue */ + + unsigned int id; /* PPS source unique ID */ + struct cdev cdev; + struct device *dev; + int devno; + struct fasync_struct *async_queue; /* fasync method */ + spinlock_t lock; + + atomic_t usage; /* usage count */ +}; + +/* + * Global variables + */ + +extern spinlock_t pps_idr_lock; +extern struct idr pps_idr; +extern struct timespec pps_irq_ts[]; + +extern struct device_attribute pps_attrs[]; + +/* + * Exported functions + */ + +struct pps_device *pps_get_source(int source); +extern void pps_put_source(struct pps_device *pps); +extern int pps_register_source(struct pps_source_info *info, + int default_params); +extern void pps_unregister_source(int source); +extern int pps_register_cdev(struct pps_device *pps); +extern void pps_unregister_cdev(struct pps_device *pps); +extern void pps_event(int source, struct pps_ktime *ts, int event, void *data); -- cgit v1.2.3