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 <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>
This commit is contained in:
Rodolfo Giometti
Linus Torvalds
parent
8820f27ad9
commit
eae9d2ba0c
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@ -0,0 +1,73 @@
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What: /sys/class/pps/
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Date: February 2008
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Contact: Rodolfo Giometti <giometti@linux.it>
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Description:
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The /sys/class/pps/ directory will contain files and
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directories that will provide a unified interface to
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the PPS sources.
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What: /sys/class/pps/ppsX/
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Date: February 2008
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Contact: Rodolfo Giometti <giometti@linux.it>
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Description:
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The /sys/class/pps/ppsX/ directory is related to X-th
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PPS source into the system. Each directory will
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contain files to manage and control its PPS source.
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What: /sys/class/pps/ppsX/assert
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Date: February 2008
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Contact: Rodolfo Giometti <giometti@linux.it>
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Description:
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The /sys/class/pps/ppsX/assert file reports the assert events
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and the assert sequence number of the X-th source in the form:
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<secs>.<nsec>#<sequence>
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If the source has no assert events the content of this file
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is empty.
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What: /sys/class/pps/ppsX/clear
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Date: February 2008
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Contact: Rodolfo Giometti <giometti@linux.it>
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Description:
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The /sys/class/pps/ppsX/clear file reports the clear events
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and the clear sequence number of the X-th source in the form:
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<secs>.<nsec>#<sequence>
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If the source has no clear events the content of this file
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is empty.
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What: /sys/class/pps/ppsX/mode
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Date: February 2008
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Contact: Rodolfo Giometti <giometti@linux.it>
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Description:
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The /sys/class/pps/ppsX/mode file reports the functioning
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mode of the X-th source in hexadecimal encoding.
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Please, refer to linux/include/linux/pps.h for further
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info.
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What: /sys/class/pps/ppsX/echo
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Date: February 2008
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Contact: Rodolfo Giometti <giometti@linux.it>
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Description:
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The /sys/class/pps/ppsX/echo file reports if the X-th does
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or does not support an "echo" function.
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What: /sys/class/pps/ppsX/name
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Date: February 2008
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Contact: Rodolfo Giometti <giometti@linux.it>
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Description:
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The /sys/class/pps/ppsX/name file reports the name of the
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X-th source.
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What: /sys/class/pps/ppsX/path
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Date: February 2008
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Contact: Rodolfo Giometti <giometti@linux.it>
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Description:
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The /sys/class/pps/ppsX/path file reports the path name of
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the device connected with the X-th source.
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If the source is not connected with any device the content
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of this file is empty.
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@ -149,6 +149,8 @@ Code Seq# Include File Comments
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'p' 40-7F linux/nvram.h
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'p' 80-9F user-space parport
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<mailto:tim@cyberelk.net>
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'p' a1-a4 linux/pps.h LinuxPPS
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<mailto:giometti@linux.it>
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'q' 00-1F linux/serio.h
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'q' 80-FF Internet PhoneJACK, Internet LineJACK
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<http://www.quicknet.net>
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@ -0,0 +1,172 @@
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PPS - Pulse Per Second
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----------------------
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(C) Copyright 2007 Rodolfo Giometti <giometti@enneenne.com>
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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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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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Overview
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--------
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LinuxPPS provides a programming interface (API) to define in the
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system several PPS sources.
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PPS means "pulse per second" and a PPS source is just a device which
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provides a high precision signal each second so that an application
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can use it to adjust system clock time.
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A PPS source can be connected to a serial port (usually to the Data
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Carrier Detect pin) or to a parallel port (ACK-pin) or to a special
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CPU's GPIOs (this is the common case in embedded systems) but in each
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case when a new pulse arrives the system must apply to it a timestamp
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and record it for userland.
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Common use is the combination of the NTPD as userland program, with a
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GPS receiver as PPS source, to obtain a wallclock-time with
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sub-millisecond synchronisation to UTC.
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RFC considerations
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------------------
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While implementing a PPS API as RFC 2783 defines and using an embedded
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CPU GPIO-Pin as physical link to the signal, I encountered a deeper
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problem:
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At startup it needs a file descriptor as argument for the function
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time_pps_create().
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This implies that the source has a /dev/... entry. This assumption is
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ok for the serial and parallel port, where you can do something
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useful besides(!) the gathering of timestamps as it is the central
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task for a PPS-API. But this assumption does not work for a single
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purpose GPIO line. In this case even basic file-related functionality
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(like read() and write()) makes no sense at all and should not be a
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precondition for the use of a PPS-API.
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The problem can be simply solved if you consider that a PPS source is
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not always connected with a GPS data source.
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So your programs should check if the GPS data source (the serial port
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for instance) is a PPS source too, and if not they should provide the
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possibility to open another device as PPS source.
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In LinuxPPS the PPS sources are simply char devices usually mapped
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into files /dev/pps0, /dev/pps1, etc..
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Coding example
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--------------
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To register a PPS source into the kernel you should define a struct
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pps_source_info_s as follows:
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static struct pps_source_info pps_ktimer_info = {
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.name = "ktimer",
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.path = "",
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.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT | \
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PPS_ECHOASSERT | \
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PPS_CANWAIT | PPS_TSFMT_TSPEC,
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.echo = pps_ktimer_echo,
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.owner = THIS_MODULE,
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};
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and then calling the function pps_register_source() in your
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intialization routine as follows:
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source = pps_register_source(&pps_ktimer_info,
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PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
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The pps_register_source() prototype is:
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int pps_register_source(struct pps_source_info_s *info, int default_params)
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where "info" is a pointer to a structure that describes a particular
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PPS source, "default_params" tells the system what the initial default
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parameters for the device should be (it is obvious that these parameters
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must be a subset of ones defined in the struct
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pps_source_info_s which describe the capabilities of the driver).
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Once you have registered a new PPS source into the system you can
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signal an assert event (for example in the interrupt handler routine)
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just using:
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pps_event(source, &ts, PPS_CAPTUREASSERT, ptr)
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where "ts" is the event's timestamp.
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The same function may also run the defined echo function
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(pps_ktimer_echo(), passing to it the "ptr" pointer) if the user
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asked for that... etc..
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Please see the file drivers/pps/clients/ktimer.c for example code.
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SYSFS support
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-------------
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If the SYSFS filesystem is enabled in the kernel it provides a new class:
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$ ls /sys/class/pps/
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pps0/ pps1/ pps2/
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Every directory is the ID of a PPS sources defined in the system and
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inside you find several files:
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$ ls /sys/class/pps/pps0/
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assert clear echo mode name path subsystem@ uevent
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Inside each "assert" and "clear" file you can find the timestamp and a
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sequence number:
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$ cat /sys/class/pps/pps0/assert
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1170026870.983207967#8
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Where before the "#" is the timestamp in seconds; after it is the
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sequence number. Other files are:
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* echo: reports if the PPS source has an echo function or not;
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* mode: reports available PPS functioning modes;
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* name: reports the PPS source's name;
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* path: reports the PPS source's device path, that is the device the
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PPS source is connected to (if it exists).
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Testing the PPS support
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-----------------------
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In order to test the PPS support even without specific hardware you can use
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the ktimer driver (see the client subsection in the PPS configuration menu)
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and the userland tools provided into Documentaion/pps/ directory.
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Once you have enabled the compilation of ktimer just modprobe it (if
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not statically compiled):
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# modprobe ktimer
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and the run ppstest as follow:
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$ ./ppstest /dev/pps0
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trying PPS source "/dev/pps1"
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found PPS source "/dev/pps1"
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ok, found 1 source(s), now start fetching data...
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source 0 - assert 1186592699.388832443, sequence: 364 - clear 0.000000000, sequence: 0
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source 0 - assert 1186592700.388931295, sequence: 365 - clear 0.000000000, sequence: 0
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source 0 - assert 1186592701.389032765, sequence: 366 - clear 0.000000000, sequence: 0
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Please, note that to compile userland programs you need the file timepps.h
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(see Documentation/pps/).
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@ -4577,6 +4577,13 @@ S: Maintained
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F: drivers/net/pppol2tp.c
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F: include/linux/if_pppol2tp.h
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PPS SUPPORT
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P: Rodolfo Giometti
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M: giometti@enneenne.com
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W: http://wiki.enneenne.com/index.php/LinuxPPS_support
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L: linuxpps@ml.enneenne.com (subscribers-only)
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S: Maintained
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PREEMPTIBLE KERNEL
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P: Robert Love
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M: rml@tech9.net
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@ -52,6 +52,8 @@ source "drivers/i2c/Kconfig"
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source "drivers/spi/Kconfig"
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source "drivers/pps/Kconfig"
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source "drivers/gpio/Kconfig"
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source "drivers/w1/Kconfig"
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@ -72,6 +72,7 @@ obj-$(CONFIG_INPUT) += input/
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obj-$(CONFIG_I2O) += message/
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obj-$(CONFIG_RTC_LIB) += rtc/
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obj-y += i2c/ media/
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obj-$(CONFIG_PPS) += pps/
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obj-$(CONFIG_W1) += w1/
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obj-$(CONFIG_POWER_SUPPLY) += power/
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obj-$(CONFIG_HWMON) += hwmon/
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@ -0,0 +1,33 @@
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#
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# PPS support configuration
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#
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menu "PPS support"
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config PPS
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tristate "PPS support"
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depends on EXPERIMENTAL
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---help---
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PPS (Pulse Per Second) is a special pulse provided by some GPS
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antennae. Userland can use it to get a high-precision time
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reference.
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Some antennae's PPS signals are connected with the CD (Carrier
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Detect) pin of the serial line they use to communicate with the
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host. In this case use the SERIAL_LINE client support.
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Some antennae's PPS signals are connected with some special host
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inputs so you have to enable the corresponding client support.
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To compile this driver as a module, choose M here: the module
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will be called pps_core.ko.
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config PPS_DEBUG
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bool "PPS debugging messages"
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depends on PPS
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help
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Say Y here if you want the PPS support to produce a bunch of debug
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messages to the system log. Select this if you are having a
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problem with PPS support and want to see more of what is going on.
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endmenu
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@ -0,0 +1,8 @@
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#
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# Makefile for the PPS core.
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#
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pps_core-y := pps.o kapi.o sysfs.o
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obj-$(CONFIG_PPS) := pps_core.o
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ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG
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@ -0,0 +1,329 @@
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/*
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* kernel API
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*
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*
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* Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it>
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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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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/time.h>
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#include <linux/spinlock.h>
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#include <linux/idr.h>
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#include <linux/fs.h>
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#include <linux/pps_kernel.h>
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/*
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* Global variables
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*/
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DEFINE_SPINLOCK(pps_idr_lock);
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DEFINE_IDR(pps_idr);
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/*
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* Local functions
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*/
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static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset)
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{
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ts->nsec += offset->nsec;
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while (ts->nsec >= NSEC_PER_SEC) {
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ts->nsec -= NSEC_PER_SEC;
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ts->sec++;
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}
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while (ts->nsec < 0) {
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ts->nsec += NSEC_PER_SEC;
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ts->sec--;
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}
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ts->sec += offset->sec;
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}
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/*
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* Exported functions
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*/
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/* pps_get_source - find a PPS source
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* @source: the PPS source ID.
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*
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* This function is used to find an already registered PPS source into the
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* system.
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*
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* The function returns NULL if found nothing, otherwise it returns a pointer
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* to the PPS source data struct (the refcounter is incremented by 1).
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*/
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struct pps_device *pps_get_source(int source)
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{
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struct pps_device *pps;
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unsigned long flags;
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spin_lock_irqsave(&pps_idr_lock, flags);
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pps = idr_find(&pps_idr, source);
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if (pps != NULL)
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atomic_inc(&pps->usage);
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spin_unlock_irqrestore(&pps_idr_lock, flags);
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return pps;
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}
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/* pps_put_source - free the PPS source data
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* @pps: a pointer to the PPS source.
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*
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* This function is used to free a PPS data struct if its refcount is 0.
|
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*/
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|
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void pps_put_source(struct pps_device *pps)
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{
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unsigned long flags;
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spin_lock_irqsave(&pps_idr_lock, flags);
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BUG_ON(atomic_read(&pps->usage) == 0);
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if (!atomic_dec_and_test(&pps->usage)) {
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pps = NULL;
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goto exit;
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}
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/* No more reference to the PPS source. We can safely remove the
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* PPS data struct.
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*/
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idr_remove(&pps_idr, pps->id);
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exit:
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spin_unlock_irqrestore(&pps_idr_lock, flags);
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kfree(pps);
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}
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/* pps_register_source - add a PPS source in the system
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* @info: the PPS info struct
|
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* @default_params: the default PPS parameters of the new source
|
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*
|
||||
* This function is used to add a new PPS source in the system. The new
|
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* source is described by info's fields and it will have, as default PPS
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* parameters, the ones specified into default_params.
|
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*
|
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* The function returns, in case of success, the PPS source ID.
|
||||
*/
|
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|
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int pps_register_source(struct pps_source_info *info, int default_params)
|
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{
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struct pps_device *pps;
|
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int id;
|
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int err;
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||||
|
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/* Sanity checks */
|
||||
if ((info->mode & default_params) != default_params) {
|
||||
printk(KERN_ERR "pps: %s: unsupported default parameters\n",
|
||||
info->name);
|
||||
err = -EINVAL;
|
||||
goto pps_register_source_exit;
|
||||
}
|
||||
if ((info->mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) != 0 &&
|
||||
info->echo == NULL) {
|
||||
printk(KERN_ERR "pps: %s: echo function is not defined\n",
|
||||
info->name);
|
||||
err = -EINVAL;
|
||||
goto pps_register_source_exit;
|
||||
}
|
||||
if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
|
||||
printk(KERN_ERR "pps: %s: unspecified time format\n",
|
||||
info->name);
|
||||
err = -EINVAL;
|
||||
goto pps_register_source_exit;
|
||||
}
|
||||
|
||||
/* Allocate memory for the new PPS source struct */
|
||||
pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL);
|
||||
if (pps == NULL) {
|
||||
err = -ENOMEM;
|
||||
goto pps_register_source_exit;
|
||||
}
|
||||
|
||||
/* These initializations must be done before calling idr_get_new()
|
||||
* in order to avoid reces into pps_event().
|
||||
*/
|
||||
pps->params.api_version = PPS_API_VERS;
|
||||
pps->params.mode = default_params;
|
||||
pps->info = *info;
|
||||
|
||||
init_waitqueue_head(&pps->queue);
|
||||
spin_lock_init(&pps->lock);
|
||||
atomic_set(&pps->usage, 1);
|
||||
|
||||
/* Get new ID for the new PPS source */
|
||||
if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) {
|
||||
err = -ENOMEM;
|
||||
goto kfree_pps;
|
||||
}
|
||||
|
||||
spin_lock_irq(&pps_idr_lock);
|
||||
|
||||
/* Now really allocate the PPS source.
|
||||
* After idr_get_new() calling the new source will be freely available
|
||||
* into the kernel.
|
||||
*/
|
||||
err = idr_get_new(&pps_idr, pps, &id);
|
||||
if (err < 0) {
|
||||
spin_unlock_irq(&pps_idr_lock);
|
||||
goto kfree_pps;
|
||||
}
|
||||
|
||||
id = id & MAX_ID_MASK;
|
||||
if (id >= PPS_MAX_SOURCES) {
|
||||
spin_unlock_irq(&pps_idr_lock);
|
||||
|
||||
printk(KERN_ERR "pps: %s: too many PPS sources in the system\n",
|
||||
info->name);
|
||||
err = -EBUSY;
|
||||
goto free_idr;
|
||||
}
|
||||
pps->id = id;
|
||||
|
||||
spin_unlock_irq(&pps_idr_lock);
|
||||
|
||||
/* Create the char device */
|
||||
err = pps_register_cdev(pps);
|
||||
if (err < 0) {
|
||||
printk(KERN_ERR "pps: %s: unable to create char device\n",
|
||||
info->name);
|
||||
goto free_idr;
|
||||
}
|
||||
|
||||
pr_info("new PPS source %s at ID %d\n", info->name, id);
|
||||
|
||||
return id;
|
||||
|
||||
free_idr:
|
||||
spin_lock_irq(&pps_idr_lock);
|
||||
idr_remove(&pps_idr, id);
|
||||
spin_unlock_irq(&pps_idr_lock);
|
||||
|
||||
kfree_pps:
|
||||
kfree(pps);
|
||||
|
||||
pps_register_source_exit:
|
||||
printk(KERN_ERR "pps: %s: unable to register source\n", info->name);
|
||||
|
||||
return err;
|
||||
}
|
||||
EXPORT_SYMBOL(pps_register_source);
|
||||
|
||||
/* pps_unregister_source - remove a PPS source from the system
|
||||
* @source: the PPS source ID
|
||||
*
|
||||
* This function is used to remove a previously registered PPS source from
|
||||
* the system.
|
||||
*/
|
||||
|
||||
void pps_unregister_source(int source)
|
||||
{
|
||||
struct pps_device *pps;
|
||||
|
||||
spin_lock_irq(&pps_idr_lock);
|
||||
pps = idr_find(&pps_idr, source);
|
||||
|
||||
if (!pps) {
|
||||
BUG();
|
||||
spin_unlock_irq(&pps_idr_lock);
|
||||
return;
|
||||
}
|
||||
spin_unlock_irq(&pps_idr_lock);
|
||||
|
||||
pps_unregister_cdev(pps);
|
||||
pps_put_source(pps);
|
||||
}
|
||||
EXPORT_SYMBOL(pps_unregister_source);
|
||||
|
||||
/* pps_event - register a PPS event into the system
|
||||
* @source: the PPS source ID
|
||||
* @ts: the event timestamp
|
||||
* @event: the event type
|
||||
* @data: userdef pointer
|
||||
*
|
||||
* This function is used by each PPS client in order to register a new
|
||||
* PPS event into the system (it's usually called inside an IRQ handler).
|
||||
*
|
||||
* If an echo function is associated with the PPS source it will be called
|
||||
* as:
|
||||
* pps->info.echo(source, event, data);
|
||||
*/
|
||||
|
||||
void pps_event(int source, struct pps_ktime *ts, int event, void *data)
|
||||
{
|
||||
struct pps_device *pps;
|
||||
unsigned long flags;
|
||||
|
||||
if ((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0) {
|
||||
printk(KERN_ERR "pps: unknown event (%x) for source %d\n",
|
||||
event, source);
|
||||
return;
|
||||
}
|
||||
|
||||
pps = pps_get_source(source);
|
||||
if (!pps)
|
||||
return;
|
||||
|
||||
pr_debug("PPS event on source %d at %llu.%06u\n",
|
||||
pps->id, (unsigned long long) ts->sec, ts->nsec);
|
||||
|
||||
spin_lock_irqsave(&pps->lock, flags);
|
||||
|
||||
/* Must call the echo function? */
|
||||
if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)))
|
||||
pps->info.echo(source, event, data);
|
||||
|
||||
/* Check the event */
|
||||
pps->current_mode = pps->params.mode;
|
||||
if (event & PPS_CAPTUREASSERT) {
|
||||
/* We have to add an offset? */
|
||||
if (pps->params.mode & PPS_OFFSETASSERT)
|
||||
pps_add_offset(ts, &pps->params.assert_off_tu);
|
||||
|
||||
/* Save the time stamp */
|
||||
pps->assert_tu = *ts;
|
||||
pps->assert_sequence++;
|
||||
pr_debug("capture assert seq #%u for source %d\n",
|
||||
pps->assert_sequence, source);
|
||||
}
|
||||
if (event & PPS_CAPTURECLEAR) {
|
||||
/* We have to add an offset? */
|
||||
if (pps->params.mode & PPS_OFFSETCLEAR)
|
||||
pps_add_offset(ts, &pps->params.clear_off_tu);
|
||||
|
||||
/* Save the time stamp */
|
||||
pps->clear_tu = *ts;
|
||||
pps->clear_sequence++;
|
||||
pr_debug("capture clear seq #%u for source %d\n",
|
||||
pps->clear_sequence, source);
|
||||
}
|
||||
|
||||
pps->go = ~0;
|
||||
wake_up_interruptible(&pps->queue);
|
||||
|
||||
kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
|
||||
|
||||
spin_unlock_irqrestore(&pps->lock, flags);
|
||||
|
||||
/* Now we can release the PPS source for (possible) deregistration */
|
||||
pps_put_source(pps);
|
||||
}
|
||||
EXPORT_SYMBOL(pps_event);
|
||||
|
|
@ -0,0 +1,312 @@
|
|||
/*
|
||||
* PPS core file
|
||||
*
|
||||
*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/init.h>
|
||||
#include <linux/sched.h>
|
||||
#include <linux/uaccess.h>
|
||||
#include <linux/idr.h>
|
||||
#include <linux/cdev.h>
|
||||
#include <linux/poll.h>
|
||||
#include <linux/pps_kernel.h>
|
||||
|
||||
/*
|
||||
* Local variables
|
||||
*/
|
||||
|
||||
static dev_t pps_devt;
|
||||
static struct class *pps_class;
|
||||
|
||||
/*
|
||||
* Char device methods
|
||||
*/
|
||||
|
||||
static unsigned int pps_cdev_poll(struct file *file, poll_table *wait)
|
||||
{
|
||||
struct pps_device *pps = file->private_data;
|
||||
|
||||
poll_wait(file, &pps->queue, wait);
|
||||
|
||||
return POLLIN | POLLRDNORM;
|
||||
}
|
||||
|
||||
static int pps_cdev_fasync(int fd, struct file *file, int on)
|
||||
{
|
||||
struct pps_device *pps = file->private_data;
|
||||
return fasync_helper(fd, file, on, &pps->async_queue);
|
||||
}
|
||||
|
||||
static long pps_cdev_ioctl(struct file *file,
|
||||
unsigned int cmd, unsigned long arg)
|
||||
{
|
||||
struct pps_device *pps = file->private_data;
|
||||
struct pps_kparams params;
|
||||
struct pps_fdata fdata;
|
||||
unsigned long ticks;
|
||||
void __user *uarg = (void __user *) arg;
|
||||
int __user *iuarg = (int __user *) arg;
|
||||
int err;
|
||||
|
||||
switch (cmd) {
|
||||
case PPS_GETPARAMS:
|
||||
pr_debug("PPS_GETPARAMS: source %d\n", pps->id);
|
||||
|
||||
/* Return current parameters */
|
||||
err = copy_to_user(uarg, &pps->params,
|
||||
sizeof(struct pps_kparams));
|
||||
if (err)
|
||||
return -EFAULT;
|
||||
|
||||
break;
|
||||
|
||||
case PPS_SETPARAMS:
|
||||
pr_debug("PPS_SETPARAMS: source %d\n", pps->id);
|
||||
|
||||
/* Check the capabilities */
|
||||
if (!capable(CAP_SYS_TIME))
|
||||
return -EPERM;
|
||||
|
||||
err = copy_from_user(¶ms, uarg, sizeof(struct pps_kparams));
|
||||
if (err)
|
||||
return -EFAULT;
|
||||
if (!(params.mode & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR))) {
|
||||
pr_debug("capture mode unspecified (%x)\n",
|
||||
params.mode);
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
/* Check for supported capabilities */
|
||||
if ((params.mode & ~pps->info.mode) != 0) {
|
||||
pr_debug("unsupported capabilities (%x)\n",
|
||||
params.mode);
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
spin_lock_irq(&pps->lock);
|
||||
|
||||
/* Save the new parameters */
|
||||
pps->params = params;
|
||||
|
||||
/* Restore the read only parameters */
|
||||
if ((params.mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
|
||||
/* section 3.3 of RFC 2783 interpreted */
|
||||
pr_debug("time format unspecified (%x)\n",
|
||||
params.mode);
|
||||
pps->params.mode |= PPS_TSFMT_TSPEC;
|
||||
}
|
||||
if (pps->info.mode & PPS_CANWAIT)
|
||||
pps->params.mode |= PPS_CANWAIT;
|
||||
pps->params.api_version = PPS_API_VERS;
|
||||
|
||||
spin_unlock_irq(&pps->lock);
|
||||
|
||||
break;
|
||||
|
||||
case PPS_GETCAP:
|
||||
pr_debug("PPS_GETCAP: source %d\n", pps->id);
|
||||
|
||||
err = put_user(pps->info.mode, iuarg);
|
||||
if (err)
|
||||
return -EFAULT;
|
||||
|
||||
break;
|
||||
|
||||
case PPS_FETCH:
|
||||
pr_debug("PPS_FETCH: source %d\n", pps->id);
|
||||
|
||||
err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata));
|
||||
if (err)
|
||||
return -EFAULT;
|
||||
|
||||
pps->go = 0;
|
||||
|
||||
/* Manage the timeout */
|
||||
if (fdata.timeout.flags & PPS_TIME_INVALID)
|
||||
err = wait_event_interruptible(pps->queue, pps->go);
|
||||
else {
|
||||
pr_debug("timeout %lld.%09d\n",
|
||||
(long long) fdata.timeout.sec,
|
||||
fdata.timeout.nsec);
|
||||
ticks = fdata.timeout.sec * HZ;
|
||||
ticks += fdata.timeout.nsec / (NSEC_PER_SEC / HZ);
|
||||
|
||||
if (ticks != 0) {
|
||||
err = wait_event_interruptible_timeout(
|
||||
pps->queue, pps->go, ticks);
|
||||
if (err == 0)
|
||||
return -ETIMEDOUT;
|
||||
}
|
||||
}
|
||||
|
||||
/* Check for pending signals */
|
||||
if (err == -ERESTARTSYS) {
|
||||
pr_debug("pending signal caught\n");
|
||||
return -EINTR;
|
||||
}
|
||||
|
||||
/* Return the fetched timestamp */
|
||||
spin_lock_irq(&pps->lock);
|
||||
|
||||
fdata.info.assert_sequence = pps->assert_sequence;
|
||||
fdata.info.clear_sequence = pps->clear_sequence;
|
||||
fdata.info.assert_tu = pps->assert_tu;
|
||||
fdata.info.clear_tu = pps->clear_tu;
|
||||
fdata.info.current_mode = pps->current_mode;
|
||||
|
||||
spin_unlock_irq(&pps->lock);
|
||||
|
||||
err = copy_to_user(uarg, &fdata, sizeof(struct pps_fdata));
|
||||
if (err)
|
||||
return -EFAULT;
|
||||
|
||||
break;
|
||||
|
||||
default:
|
||||
return -ENOTTY;
|
||||
break;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int pps_cdev_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
struct pps_device *pps = container_of(inode->i_cdev,
|
||||
struct pps_device, cdev);
|
||||
int found;
|
||||
|
||||
found = pps_get_source(pps->id) != 0;
|
||||
if (!found)
|
||||
return -ENODEV;
|
||||
|
||||
file->private_data = pps;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int pps_cdev_release(struct inode *inode, struct file *file)
|
||||
{
|
||||
struct pps_device *pps = file->private_data;
|
||||
|
||||
/* Free the PPS source and wake up (possible) deregistration */
|
||||
pps_put_source(pps);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* Char device stuff
|
||||
*/
|
||||
|
||||
static const struct file_operations pps_cdev_fops = {
|
||||
.owner = THIS_MODULE,
|
||||
.llseek = no_llseek,
|
||||
.poll = pps_cdev_poll,
|
||||
.fasync = pps_cdev_fasync,
|
||||
.unlocked_ioctl = pps_cdev_ioctl,
|
||||
.open = pps_cdev_open,
|
||||
.release = pps_cdev_release,
|
||||
};
|
||||
|
||||
int pps_register_cdev(struct pps_device *pps)
|
||||
{
|
||||
int err;
|
||||
|
||||
pps->devno = MKDEV(MAJOR(pps_devt), pps->id);
|
||||
cdev_init(&pps->cdev, &pps_cdev_fops);
|
||||
pps->cdev.owner = pps->info.owner;
|
||||
|
||||
err = cdev_add(&pps->cdev, pps->devno, 1);
|
||||
if (err) {
|
||||
printk(KERN_ERR "pps: %s: failed to add char device %d:%d\n",
|
||||
pps->info.name, MAJOR(pps_devt), pps->id);
|
||||
return err;
|
||||
}
|
||||
pps->dev = device_create(pps_class, pps->info.dev, pps->devno, NULL,
|
||||
"pps%d", pps->id);
|
||||
if (err)
|
||||
goto del_cdev;
|
||||
dev_set_drvdata(pps->dev, pps);
|
||||
|
||||
pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,
|
||||
MAJOR(pps_devt), pps->id);
|
||||
|
||||
return 0;
|
||||
|
||||
del_cdev:
|
||||
cdev_del(&pps->cdev);
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
void pps_unregister_cdev(struct pps_device *pps)
|
||||
{
|
||||
device_destroy(pps_class, pps->devno);
|
||||
cdev_del(&pps->cdev);
|
||||
}
|
||||
|
||||
/*
|
||||
* Module stuff
|
||||
*/
|
||||
|
||||
static void __exit pps_exit(void)
|
||||
{
|
||||
class_destroy(pps_class);
|
||||
unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES);
|
||||
}
|
||||
|
||||
static int __init pps_init(void)
|
||||
{
|
||||
int err;
|
||||
|
||||
pps_class = class_create(THIS_MODULE, "pps");
|
||||
if (!pps_class) {
|
||||
printk(KERN_ERR "pps: failed to allocate class\n");
|
||||
return -ENOMEM;
|
||||
}
|
||||
pps_class->dev_attrs = pps_attrs;
|
||||
|
||||
err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps");
|
||||
if (err < 0) {
|
||||
printk(KERN_ERR "pps: failed to allocate char device region\n");
|
||||
goto remove_class;
|
||||
}
|
||||
|
||||
pr_info("LinuxPPS API ver. %d registered\n", PPS_API_VERS);
|
||||
pr_info("Software ver. %s - Copyright 2005-2007 Rodolfo Giometti "
|
||||
"<giometti@linux.it>\n", PPS_VERSION);
|
||||
|
||||
return 0;
|
||||
|
||||
remove_class:
|
||||
class_destroy(pps_class);
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
subsys_initcall(pps_init);
|
||||
module_exit(pps_exit);
|
||||
|
||||
MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
|
||||
MODULE_DESCRIPTION("LinuxPPS support (RFC 2783) - ver. " PPS_VERSION);
|
||||
MODULE_LICENSE("GPL");
|
||||
|
|
@ -0,0 +1,98 @@
|
|||
/*
|
||||
* PPS sysfs support
|
||||
*
|
||||
*
|
||||
* Copyright (C) 2007-2009 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.
|
||||
*/
|
||||
|
||||
|
||||
#include <linux/device.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/string.h>
|
||||
#include <linux/pps_kernel.h>
|
||||
|
||||
/*
|
||||
* Attribute functions
|
||||
*/
|
||||
|
||||
static ssize_t pps_show_assert(struct device *dev,
|
||||
struct device_attribute *attr, char *buf)
|
||||
{
|
||||
struct pps_device *pps = dev_get_drvdata(dev);
|
||||
|
||||
if (!(pps->info.mode & PPS_CAPTUREASSERT))
|
||||
return 0;
|
||||
|
||||
return sprintf(buf, "%lld.%09d#%d\n",
|
||||
(long long) pps->assert_tu.sec, pps->assert_tu.nsec,
|
||||
pps->assert_sequence);
|
||||
}
|
||||
|
||||
static ssize_t pps_show_clear(struct device *dev,
|
||||
struct device_attribute *attr, char *buf)
|
||||
{
|
||||
struct pps_device *pps = dev_get_drvdata(dev);
|
||||
|
||||
if (!(pps->info.mode & PPS_CAPTURECLEAR))
|
||||
return 0;
|
||||
|
||||
return sprintf(buf, "%lld.%09d#%d\n",
|
||||
(long long) pps->clear_tu.sec, pps->clear_tu.nsec,
|
||||
pps->clear_sequence);
|
||||
}
|
||||
|
||||
static ssize_t pps_show_mode(struct device *dev,
|
||||
struct device_attribute *attr, char *buf)
|
||||
{
|
||||
struct pps_device *pps = dev_get_drvdata(dev);
|
||||
|
||||
return sprintf(buf, "%4x\n", pps->info.mode);
|
||||
}
|
||||
|
||||
static ssize_t pps_show_echo(struct device *dev,
|
||||
struct device_attribute *attr, char *buf)
|
||||
{
|
||||
struct pps_device *pps = dev_get_drvdata(dev);
|
||||
|
||||
return sprintf(buf, "%d\n", !!pps->info.echo);
|
||||
}
|
||||
|
||||
static ssize_t pps_show_name(struct device *dev,
|
||||
struct device_attribute *attr, char *buf)
|
||||
{
|
||||
struct pps_device *pps = dev_get_drvdata(dev);
|
||||
|
||||
return sprintf(buf, "%s\n", pps->info.name);
|
||||
}
|
||||
|
||||
static ssize_t pps_show_path(struct device *dev,
|
||||
struct device_attribute *attr, char *buf)
|
||||
{
|
||||
struct pps_device *pps = dev_get_drvdata(dev);
|
||||
|
||||
return sprintf(buf, "%s\n", pps->info.path);
|
||||
}
|
||||
|
||||
struct device_attribute pps_attrs[] = {
|
||||
__ATTR(assert, S_IRUGO, pps_show_assert, NULL),
|
||||
__ATTR(clear, S_IRUGO, pps_show_clear, NULL),
|
||||
__ATTR(mode, S_IRUGO, pps_show_mode, NULL),
|
||||
__ATTR(echo, S_IRUGO, pps_show_echo, NULL),
|
||||
__ATTR(name, S_IRUGO, pps_show_name, NULL),
|
||||
__ATTR(path, S_IRUGO, pps_show_path, NULL),
|
||||
__ATTR_NULL,
|
||||
};
|
||||
|
|
@ -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
|
||||
|
|
|
|||
|
|
@ -0,0 +1,122 @@
|
|||
/*
|
||||
* 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_ */
|
||||
|
|
@ -0,0 +1,89 @@
|
|||
/*
|
||||
* PPS API kernel header
|
||||
*
|
||||
* Copyright (C) 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.
|
||||
*/
|
||||
|
||||
#include <linux/pps.h>
|
||||
|
||||
#include <linux/cdev.h>
|
||||
#include <linux/device.h>
|
||||
#include <linux/time.h>
|
||||
|
||||
/*
|
||||
* 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);
|
||||
Reference in New Issue