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Message-ID: <20100216153301.534f2722@desktopvm.lvknet>
Date: Tue, 16 Feb 2010 15:33:01 +0300
From: Alexander Gordeev <lasaine@....cs.msu.su>
To: Rodolfo Giometti <giometti@...ux.it>
Cc: linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>,
David Woodhouse <dwmw2@...radead.org>,
Dave Jones <davej@...hat.com>, Sam Ravnborg <sam@...nborg.org>,
Greg KH <greg@...ah.com>,
Randy Dunlap <randy.dunlap@...cle.com>,
Kay Sievers <kay.sievers@...y.org>,
Alan Cox <alan@...rguk.ukuu.org.uk>,
"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...e.hu>,
Michael Kerrisk <mtk.manpages@...il.com>,
Christoph Hellwig <hch@...radead.org>,
Rodolfo Giometti <giometti@...ux.it>
Subject: Re: [PATCH 1/8] pps: userland header file for PPS API.
Hi Rodolfo,
On Tue, 16 Feb 2010 10:51:18 +0100
Rodolfo Giometti <giometti@...ux.it> wrote:
> This patch adds into the PPS's documentation directory a possible
> implementation of the PPS API (RFC 2783) by using the LinuxPPS's char
> devices.
>
> This file is not just an example but it can be used into real
> systems. :)
Isn't libc a proper place for this file? This header file provides a
generic standardized interface (PPSAPI) to the custom Linux
implementation (linux/pps.h). I think this is just what libc is for.
I wanted to file a bug in Debian BTS last week to add this header to
libc6-dev package and also push it upstream but something distracted
me. If you agree that the header should be in libc then I can do it now.
> Signed-off-by: Rodolfo Giometti <giometti@...ux.it>
> ---
> Documentation/pps/timepps.h | 198
> +++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 198
> insertions(+), 0 deletions(-) create mode 100644
> Documentation/pps/timepps.h
>
> diff --git a/Documentation/pps/timepps.h b/Documentation/pps/timepps.h
> new file mode 100644
> index 0000000..d2628d2
> --- /dev/null
> +++ b/Documentation/pps/timepps.h
> @@ -0,0 +1,198 @@
> +/*
> + * timepps.h -- PPS API main header
> + *
> + * Copyright (C) 2005-2007 Rodolfo Giometti <giometti@...ux.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 _SYS_TIMEPPS_H_
> +#define _SYS_TIMEPPS_H_
> +
> +#include <errno.h>
> +#include <sys/time.h>
> +#include <sys/ioctl.h>
> +#include <linux/types.h>
> +#include <linux/pps.h>
> +
> +#define LINUXPPS 1 /* signal we are using
> LinuxPPS */ +
> +/*
> + * New data structures
> + */
> +
> +struct ntp_fp {
> + unsigned int integral;
> + unsigned int fractional;
> +};
> +
> +union pps_timeu {
> + struct timespec tspec;
> + struct ntp_fp ntpfp;
> + unsigned long longpad[3];
> +};
> +
> +struct pps_info {
> + unsigned long assert_sequence; /* seq. num. of assert
> event */
> + unsigned long clear_sequence; /* seq. num. of clear
> event */
> + union pps_timeu assert_tu; /* time of assert event */
> + union pps_timeu clear_tu; /* time of clear event */
> + int current_mode; /* current mode bits */
> +};
> +
> +struct pps_params {
> + int api_version; /* API version # */
> + int mode; /* mode bits */
> + union pps_timeu assert_off_tu; /* offset compensation
> for assert */
> + union pps_timeu clear_off_tu; /* offset compensation
> for clear */ +};
> +
> +typedef int pps_handle_t; /* represents a PPS source
> */ +typedef unsigned long pps_seq_t; /* sequence number */
> +typedef struct ntp_fp ntp_fp_t; /* NTP-compatible
> time stamp */ +typedef union pps_timeu pps_timeu_t; /* generic
> data type for time stamps */ +typedef struct pps_info pps_info_t;
> +typedef struct pps_params pps_params_t;
> +
> +#define assert_timestamp assert_tu.tspec
> +#define clear_timestamp clear_tu.tspec
> +
> +#define assert_timestamp_ntpfp assert_tu.ntpfp
> +#define clear_timestamp_ntpfp clear_tu.ntpfp
> +
> +#define assert_offset assert_off_tu.tspec
> +#define clear_offset clear_off_tu.tspec
> +
> +#define assert_offset_ntpfp assert_off_tu.ntpfp
> +#define clear_offset_ntpfp clear_off_tu.ntpfp
> +
> +/*
> + * The PPS API
> + */
> +
> +static __inline int time_pps_create(int source, pps_handle_t *handle)
> +{
> + int ret;
> + struct pps_kparams dummy;
> +
> + if (!handle) {
> + errno = EINVAL;
> + return -1;
> + }
> +
> + /* First we check if current device is a valid PPS one by
> + * doing a dummy PPS_GETPARAMS...
> + */
> + ret = ioctl(source, PPS_GETPARAMS, &dummy);
> + if (ret) {
> + errno = EOPNOTSUPP;
> + return -1;
> + }
> +
> + /* ... then since in LinuxPPS there are no differences
> between a
> + * "PPS source" and a "PPS handle", we simply return the
> same value.
> + */
> + *handle = source;
> +
> + return 0;
> +}
> +
> +static __inline int time_pps_destroy(pps_handle_t handle)
> +{
> + return close(handle);
> +}
> +
> +static __inline int time_pps_getparams(pps_handle_t handle,
> + pps_params_t *ppsparams)
> +{
> + int ret;
> + struct pps_kparams __ppsparams;
> +
> + ret = ioctl(handle, PPS_GETPARAMS, &__ppsparams);
> +
> + ppsparams->api_version = __ppsparams.api_version;
> + ppsparams->mode = __ppsparams.mode;
> + ppsparams->assert_off_tu.tspec.tv_sec =
> __ppsparams.assert_off_tu.sec;
> + ppsparams->assert_off_tu.tspec.tv_nsec =
> __ppsparams.assert_off_tu.nsec;
> + ppsparams->clear_off_tu.tspec.tv_sec =
> __ppsparams.clear_off_tu.sec;
> + ppsparams->clear_off_tu.tspec.tv_nsec =
> __ppsparams.clear_off_tu.nsec; +
> + return ret;
> +}
> +
> +static __inline int time_pps_setparams(pps_handle_t handle,
> + const pps_params_t
> *ppsparams) +{
> + struct pps_kparams __ppsparams;
> +
> + __ppsparams.api_version = ppsparams->api_version;
> + __ppsparams.mode = ppsparams->mode;
> + __ppsparams.assert_off_tu.sec =
> ppsparams->assert_off_tu.tspec.tv_sec;
> + __ppsparams.assert_off_tu.nsec =
> ppsparams->assert_off_tu.tspec.tv_nsec;
> + __ppsparams.clear_off_tu.sec =
> ppsparams->clear_off_tu.tspec.tv_sec;
> + __ppsparams.clear_off_tu.nsec =
> ppsparams->clear_off_tu.tspec.tv_nsec; +
> + return ioctl(handle, PPS_SETPARAMS, &__ppsparams);
> +}
> +
> +/* Get capabilities for handle */
> +static __inline int time_pps_getcap(pps_handle_t handle, int *mode)
> +{
> + return ioctl(handle, PPS_GETCAP, mode);
> +}
> +
> +static __inline int time_pps_fetch(pps_handle_t handle, const int
> tsformat,
> + pps_info_t *ppsinfobuf,
> + const struct timespec
> *timeout) +{
> + struct pps_fdata __fdata;
> + int ret;
> +
> + /* Sanity checks */
> + if (tsformat != PPS_TSFMT_TSPEC) {
> + errno = EINVAL;
> + return -1;
> + }
> +
> + if (timeout) {
> + __fdata.timeout.sec = timeout->tv_sec;
> + __fdata.timeout.nsec = timeout->tv_nsec;
> + __fdata.timeout.flags = ~PPS_TIME_INVALID;
> + } else
> + __fdata.timeout.flags = PPS_TIME_INVALID;
> +
> + ret = ioctl(handle, PPS_FETCH, &__fdata);
> +
> + ppsinfobuf->assert_sequence = __fdata.info.assert_sequence;
> + ppsinfobuf->clear_sequence = __fdata.info.clear_sequence;
> + ppsinfobuf->assert_tu.tspec.tv_sec =
> __fdata.info.assert_tu.sec;
> + ppsinfobuf->assert_tu.tspec.tv_nsec =
> __fdata.info.assert_tu.nsec;
> + ppsinfobuf->clear_tu.tspec.tv_sec =
> __fdata.info.clear_tu.sec;
> + ppsinfobuf->clear_tu.tspec.tv_nsec =
> __fdata.info.clear_tu.nsec;
> + ppsinfobuf->current_mode = __fdata.info.current_mode;
> +
> + return ret;
> +}
> +
> +static __inline int time_pps_kcbind(pps_handle_t handle,
> + const int kernel_consumer,
> + const int edge, const int
> tsformat) +{
> + /* LinuxPPS doesn't implement kernel consumer feature */
> + errno = EOPNOTSUPP;
> + return -1;
> +}
> +
> +#endif /* _SYS_TIMEPPS_H_ */
--
Alexander
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