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    Subject[PATCH 1/7] 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>
    ---
    Documentation/ABI/testing/sysfs-pps | 73 ++++++++
    Documentation/ioctl-number.txt | 2 +
    Documentation/pps/pps.txt | 170 ++++++++++++++++++
    MAINTAINERS | 7 +
    drivers/Kconfig | 2 +
    drivers/Makefile | 1 +
    drivers/pps/Kconfig | 33 ++++
    drivers/pps/Makefile | 8 +
    drivers/pps/kapi.c | 330 ++++++++++++++++++++++++++++++++++
    drivers/pps/pps.c | 335 +++++++++++++++++++++++++++++++++++
    drivers/pps/sysfs.c | 103 +++++++++++
    include/linux/Kbuild | 1 +
    include/linux/pps.h | 202 +++++++++++++++++++++
    13 files changed, 1267 insertions(+), 0 deletions(-)
    create mode 100644 Documentation/ABI/testing/sysfs-pps
    create mode 100644 Documentation/pps/pps.txt
    create mode 100644 drivers/pps/Kconfig
    create mode 100644 drivers/pps/Makefile
    create mode 100644 drivers/pps/kapi.c
    create mode 100644 drivers/pps/pps.c
    create mode 100644 drivers/pps/sysfs.c
    create mode 100644 include/linux/pps.h

    diff --git a/Documentation/ABI/testing/sysfs-pps b/Documentation/ABI/testing/sysfs-pps
    new file mode 100644
    index 0000000..8cba1d9
    --- /dev/null
    +++ b/Documentation/ABI/testing/sysfs-pps
    @@ -0,0 +1,73 @@
    +What: /sys/class/pps/
    +Date: February 2008
    +Contact: Rodolfo Giometti <giometti@linux.it>
    +Description:
    + The /sys/class/pps/ directory will contain files and
    + directories that will provide a unified interface to
    + the PPS sources.
    +
    +What: /sys/class/pps/ppsX/
    +Date: February 2008
    +Contact: Rodolfo Giometti <giometti@linux.it>
    +Description:
    + The /sys/class/pps/ppsX/ directory is related to X-th
    + PPS source into the system. Each directory will
    + contain files to manage and control its PPS source.
    +
    +What: /sys/class/pps/ppsX/assert
    +Date: February 2008
    +Contact: Rodolfo Giometti <giometti@linux.it>
    +Description:
    + The /sys/class/pps/ppsX/assert file reports the assert events
    + and the assert sequence number of the X-th source in the form:
    +
    + <secs>.<nsec>#<sequence>
    +
    + If the source has no assert events the content of this file
    + is void.
    +
    +What: /sys/class/pps/ppsX/clear
    +Date: February 2008
    +Contact: Rodolfo Giometti <giometti@linux.it>
    +Description:
    + The /sys/class/pps/ppsX/clear file reports the clear events
    + and the clear sequence number of the X-th source in the form:
    +
    + <secs>.<nsec>#<sequence>
    +
    + If the source has no clear events the content of this file
    + is void.
    +
    +What: /sys/class/pps/ppsX/mode
    +Date: February 2008
    +Contact: Rodolfo Giometti <giometti@linux.it>
    +Description:
    + The /sys/class/pps/ppsX/mode file reports the functioning
    + mode of the X-th source in hexadecimal encoding.
    +
    + Please, refer to linux/include/linux/pps.h for further
    + info.
    +
    +What: /sys/class/pps/ppsX/echo
    +Date: February 2008
    +Contact: Rodolfo Giometti <giometti@linux.it>
    +Description:
    + The /sys/class/pps/ppsX/echo file reports if the X-th source
    + supports or not an "echo" function.
    +
    +What: /sys/class/pps/ppsX/name
    +Date: February 2008
    +Contact: Rodolfo Giometti <giometti@linux.it>
    +Description:
    + The /sys/class/pps/ppsX/name file reports the name of the
    + X-th source.
    +
    +What: /sys/class/pps/ppsX/path
    +Date: February 2008
    +Contact: Rodolfo Giometti <giometti@linux.it>
    +Description:
    + The /sys/class/pps/ppsX/path file reports the path name of
    + the device connected with the X-th source.
    +
    + If the source is not connected with any device the content
    + of this file is void.
    diff --git a/Documentation/ioctl-number.txt b/Documentation/ioctl-number.txt
    index c18363b..b4c7d26 100644
    --- a/Documentation/ioctl-number.txt
    +++ b/Documentation/ioctl-number.txt
    @@ -97,6 +97,8 @@ Code Seq# Include File Comments
    'M' all linux/soundcard.h
    'N' 00-1F drivers/usb/scanner.h
    'P' all linux/soundcard.h
    +'P' 00-04 linux/pps.h LinuxPPS
    + <mailto:giometti@linux.it>
    'Q' all linux/soundcard.h
    'R' 00-1F linux/random.h
    'S' all linux/cdrom.h conflict!
    diff --git a/Documentation/pps/pps.txt b/Documentation/pps/pps.txt
    new file mode 100644
    index 0000000..2b25a48
    --- /dev/null
    +++ b/Documentation/pps/pps.txt
    @@ -0,0 +1,170 @@
    +
    + PPS - Pulse Per Second
    + ----------------------
    +
    +(C) Copyright 2007 Rodolfo Giometti <giometti@enneenne.com>
    +
    +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.
    +
    +
    +
    +Overview
    +--------
    +
    +LinuxPPS provides a programming interface (API) to define into the
    +system several PPS sources.
    +
    +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.
    +
    +A PPS source can be connected to a serial port (usually to the Data
    +Carrier Detect pin) or to a parallel port (ACK-pin) or to a special
    +CPU's GPIOs (this is the common case in embedded systems) but in each
    +case when a new pulse comes the system must apply to it a timestamp
    +and record it for the userland.
    +
    +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.
    +
    +
    +RFC considerations
    +------------------
    +
    +While implementing a PPS API as RFC 2783 defines and using an embedded
    +CPU GPIO-Pin as physical link to the signal, I encountered a deeper
    +problem:
    +
    + At startup it needs a file descriptor as argument for the function
    + time_pps_create().
    +
    +This implies that the source has a /dev/... entry. This assumption is
    +ok for the serial and parallel port, where you can do something
    +useful besides(!) the gathering of timestamps as it is the central
    +task for a PPS-API. But this assumption does not work for a single
    +purpose GPIO line. In this case even basic file-related functionality
    +(like read() and write()) makes no sense at all and should not be a
    +precondition for the use of a PPS-API.
    +
    +The problem can be simply solved if you consider that a PPS source is
    +not always connected with a GPS data source.
    +
    +So your programs should check if the GPS data source (the serial port
    +for instance) is a PPS source too, otherwise they should provide the
    +possibility to open another device as PPS source.
    +
    +In LinuxPPS the PPS sources are simply char devices usually mapped
    +into files /dev/pps0, /dev/pps1, etc..
    +
    +
    +Coding example
    +--------------
    +
    +To register a PPS source into the kernel you should define a struct
    +pps_source_info_s as follow:
    +
    + static struct pps_source_info pps_ktimer_info = {
    + .name = "ktimer",
    + .path = "",
    + .mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT | \
    + PPS_ECHOASSERT | \
    + PPS_CANWAIT | PPS_TSFMT_TSPEC,
    + .echo = pps_ktimer_echo,
    + .owner = THIS_MODULE,
    + };
    +
    +and then calling the function pps_register_source() in your
    +intialization routine as follow:
    +
    + source = pps_register_source(&pps_ktimer_info,
    + PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
    +
    +The pps_register_source() prototype is:
    +
    + int pps_register_source(struct pps_source_info_s *info, int default_params)
    +
    +where "info" is a pointer to a structure that describes a particular
    +PPS source, "default_params" tells the system what the initial default
    +parameters for the device should be (is obvious that these parameters
    +must be a subset of ones defined into the struct
    +pps_source_info_s which describe the capabilities of the driver).
    +
    +Once you have registered a new PPS source into the system you can
    +signal an assert event (for example in the interrupt handler routine)
    +just using:
    +
    + pps_event(source, PPS_CAPTUREASSERT, ptr);
    +
    +The same function may also run the defined echo function
    +(pps_ktimer_echo(), passing to it the "ptr" pointer) if the user
    +asked for that... etc..
    +
    +Please see the file drivers/pps/clients/ktimer.c for example code.
    +
    +
    +SYSFS support
    +-------------
    +
    +If the SYSFS filesystem is enabled in the kernel it provides a new class:
    +
    + $ ls /sys/class/pps/
    + pps0/ pps1/ pps2/
    +
    +Every directory is the ID of a PPS sources defined into the system and
    +inside you find several files:
    +
    + $ ls /sys/class/pps/pps0/
    + assert clear echo mode name path subsystem@ uevent
    +
    +Inside each "assert" and "clear" file you can find the timestamp and a
    +sequence number:
    +
    + $ cat /sys/class/pps/pps0/assert
    + 1170026870.983207967#8
    +
    +Where before the "#" is the timestamp in seconds and after it is the
    +sequence number. Other files are:
    +
    +* echo: reports if the PPS source has an echo function or not;
    +
    +* mode: reports available PPS functioning modes;
    +
    +* name: reports the PPS source's name;
    +
    +* path: reports the PPS source's device path, that is the device the
    + PPS source is connected to (if it exists).
    +
    +
    +Testing the PPS support
    +-----------------------
    +
    +In order to test the PPS support even without specific hardware you can use
    +the ktimer driver (see the client subsection in the PPS configuration menu)
    +and the userland tools provided into Documentaion/pps/ directory.
    +
    +Once you have enabled the compilation of ktimer just modprobe it (if
    +not statically compiled):
    +
    + # modprobe ktimer
    +
    +and the run ppstest as follow:
    +
    + $ ./ppstest /dev/pps0
    + trying PPS source "/dev/pps1"
    + found PPS source "/dev/pps1"
    + ok, found 1 source(s), now start fetching data...
    + source 0 - assert 1186592699.388832443, sequence: 364 - clear 0.000000000, sequence: 0
    + source 0 - assert 1186592700.388931295, sequence: 365 - clear 0.000000000, sequence: 0
    + source 0 - assert 1186592701.389032765, sequence: 366 - clear 0.000000000, sequence: 0
    +
    +Please, note that to compile userland programs you need the file timepps.h
    +(see Documentation/pps/).
    diff --git a/MAINTAINERS b/MAINTAINERS
    index 90dcbbc..a67d624 100644
    --- a/MAINTAINERS
    +++ b/MAINTAINERS
    @@ -3171,6 +3171,13 @@ P: James Chapman
    M: jchapman@katalix.com
    S: Maintained

    +PPS SUPPORT
    +P: Rodolfo Giometti
    +M: giometti@enneenne.com
    +W: http://wiki.enneenne.com/index.php/LinuxPPS_support
    +L: linuxpps@ml.enneenne.com
    +S: Maintained
    +
    PREEMPTIBLE KERNEL
    P: Robert Love
    M: rml@tech9.net
    diff --git a/drivers/Kconfig b/drivers/Kconfig
    index 3a0e354..0c11e5c 100644
    --- a/drivers/Kconfig
    +++ b/drivers/Kconfig
    @@ -52,6 +52,8 @@ source "drivers/i2c/Kconfig"

    source "drivers/spi/Kconfig"

    +source "drivers/pps/Kconfig"
    +
    source "drivers/gpio/Kconfig"

    source "drivers/w1/Kconfig"
    diff --git a/drivers/Makefile b/drivers/Makefile
    index e5e394a..adc0924 100644
    --- a/drivers/Makefile
    +++ b/drivers/Makefile
    @@ -62,6 +62,7 @@ obj-$(CONFIG_INPUT) += input/
    obj-$(CONFIG_I2O) += message/
    obj-$(CONFIG_RTC_LIB) += rtc/
    obj-y += i2c/
    +obj-$(CONFIG_PPS) += pps/
    obj-$(CONFIG_W1) += w1/
    obj-$(CONFIG_POWER_SUPPLY) += power/
    obj-$(CONFIG_HWMON) += hwmon/
    diff --git a/drivers/pps/Kconfig b/drivers/pps/Kconfig
    new file mode 100644
    index 0000000..cc2eb8e
    --- /dev/null
    +++ b/drivers/pps/Kconfig
    @@ -0,0 +1,33 @@
    +#
    +# PPS support configuration
    +#
    +
    +menu "PPS support"
    +
    +config PPS
    + tristate "PPS support"
    + depends on EXPERIMENTAL
    + ---help---
    + PPS (Pulse Per Second) is a special pulse provided by some GPS
    + antennae. Userland can use it to get a high-precision time
    + reference.
    +
    + Some antennae's PPS signals are connected with the CD (Carrier
    + Detect) pin of the serial line they use to communicate with the
    + host. In this case use the SERIAL_LINE client support.
    +
    + Some antennae's PPS signals are connected with some special host
    + inputs so you have to enable the corresponding client support.
    +
    + To compile this driver as a module, choose M here: the module
    + will be called pps_core.ko.
    +
    +config PPS_DEBUG
    + bool "PPS debugging messages"
    + depends on PPS
    + help
    + Say Y here if you want the PPS support to produce a bunch of debug
    + messages to the system log. Select this if you are having a
    + problem with PPS support and want to see more of what is going on.
    +
    +endmenu
    diff --git a/drivers/pps/Makefile b/drivers/pps/Makefile
    new file mode 100644
    index 0000000..19ea582
    --- /dev/null
    +++ b/drivers/pps/Makefile
    @@ -0,0 +1,8 @@
    +#
    +# Makefile for the PPS core.
    +#
    +
    +pps_core-y := pps.o kapi.o sysfs.o
    +obj-$(CONFIG_PPS) := pps_core.o
    +
    +ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG
    diff --git a/drivers/pps/kapi.c b/drivers/pps/kapi.c
    new file mode 100644
    index 0000000..6c72e2e
    --- /dev/null
    +++ b/drivers/pps/kapi.c
    @@ -0,0 +1,330 @@
    +/*
    + * kapi.c -- kernel API
    + *
    + *
    + * Copyright (C) 2005-2007 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/time.h>
    +#include <linux/spinlock.h>
    +#include <linux/idr.h>
    +#include <linux/fs.h>
    +#include <linux/pps.h>
    +
    +/*
    + * Global variables
    + */
    +
    +DEFINE_SPINLOCK(pps_idr_lock);
    +DEFINE_IDR(pps_idr);
    +
    +/*
    + * Local functions
    + */
    +
    +static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset)
    +{
    + ts->nsec += offset->nsec;
    + while (ts->nsec >= NSEC_PER_SEC) {
    + ts->nsec -= NSEC_PER_SEC;
    + ts->sec++;
    + }
    + while (ts->nsec < 0) {
    + ts->nsec += NSEC_PER_SEC;
    + ts->sec--;
    + }
    + ts->sec += offset->sec;
    +}
    +
    +/*
    + * Exported functions
    + */
    +
    +/* pps_get_source - find a PPS source
    + *
    + * source: the PPS source ID.
    + *
    + * This function is used to find an already registered PPS source into the
    + * system.
    + *
    + * The function returns NULL if found nothing, otherwise it returns a pointer
    + * to the PPS source data struct (the refcounter is incremented by 1).
    + */
    +
    +struct pps_device *pps_get_source(int source)
    +{
    + struct pps_device *pps;
    + unsigned long flags;
    +
    + spin_lock_irqsave(&pps_idr_lock, flags);
    +
    + pps = idr_find(&pps_idr, source);
    + if (pps != NULL)
    + atomic_inc(&pps->usage);
    +
    + spin_unlock_irqrestore(&pps_idr_lock, flags);
    +
    + return pps;
    +}
    +
    +/* pps_put_source - free the PPS source data
    + *
    + * pps: a pointer to the PPS source.
    + *
    + * This function is used to free a PPS data struct if its refcount is 0.
    + */
    +
    +void pps_put_source(struct pps_device *pps)
    +{
    + unsigned long flags;
    +
    + spin_lock_irqsave(&pps_idr_lock, flags);
    + BUG_ON(atomic_read(&pps->usage) == 0);
    +
    + if (!atomic_dec_and_test(&pps->usage)) {
    + pps = NULL;
    + goto exit;
    + }
    +
    + /* No more reference to the PPS source. We can safely remove the
    + * PPS data struct.
    + */
    + idr_remove(&pps_idr, pps->id);
    +
    +exit:
    + spin_unlock_irqrestore(&pps_idr_lock, flags);
    + kfree(pps);
    +}
    +
    +/* pps_register_source - add a PPS source in the system
    + *
    + * info: the PPS info struct
    + * default_params: the default PPS parameters of the new source
    + *
    + * This function is used to add a new PPS source in the system. The new
    + * source is described by info's fields and it will have, as default PPS
    + * parameters, the ones specified into default_params.
    + *
    + * The function returns, in case of success, the PPS source ID.
    + */
    +
    +int pps_register_source(struct pps_source_info *info, int default_params)
    +{
    + struct pps_device *pps;
    + int id;
    + int err;
    +
    + /* 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;
    + }
    +
    + /* 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);
    + err = idr_get_new(&pps_idr, pps, &id);
    + spin_unlock_irq(&pps_idr_lock);
    +
    + if (err < 0)
    + goto kfree_pps;
    +
    + id = id & MAX_ID_MASK;
    + if (id >= PPS_MAX_SOURCES) {
    + printk(KERN_ERR "pps: %s: too many PPS sources in the system\n",
    + info->name);
    + err = -EBUSY;
    + goto free_idr;
    + }
    +
    + pps->id = id;
    + 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);
    +
    + /* 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
    + * 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, int event, void *data)
    +{
    + struct pps_device *pps;
    + struct timespec __ts;
    + struct pps_ktime ts;
    + unsigned long flags;
    +
    + /* First of all we get the time stamp... */
    + getnstimeofday(&__ts);
    +
    + /* ... and translate it to PPS time data struct */
    + ts.sec = __ts.tv_sec;
    + ts.nsec = __ts.tv_nsec;
    +
    + 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);
    diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
    new file mode 100644
    index 0000000..a46f8f4
    --- /dev/null
    +++ b/drivers/pps/pps.c
    @@ -0,0 +1,335 @@
    +/*
    + * pps.c -- Main PPS support file
    + *
    + *
    + * Copyright (C) 2005-2007 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.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 int pps_cdev_ioctl(struct inode *inode, 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_CHECK:
    +
    + /* This does nothing but signal we are a PPS source... */
    +
    + return 0;
    +
    + case PPS_GETPARAMS:
    + pr_debug("PPS_GETPARAMS: source %d\n", pps->id);
    +
    + /* Sanity checks */
    + if (!uarg)
    + return -EINVAL;
    +
    + /* 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;
    +
    + /* Sanity checks */
    + if (!uarg)
    + return -EINVAL;
    + err = copy_from_user(&params, 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);
    +
    + /* Sanity checks */
    + if (!uarg)
    + return -EINVAL;
    +
    + err = put_user(pps->info.mode, iuarg);
    + if (err)
    + return -EFAULT;
    +
    + break;
    +
    + case PPS_FETCH:
    + pr_debug("PPS_FETCH: source %d\n", pps->id);
    +
    + if (!uarg)
    + return -EINVAL;
    + 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,
    + .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,
    + "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);
    +
    + if (pps_devt)
    + unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES);
    +
    + pr_info("LinuxPPS API ver. %d removed\n", PPS_API_VERS);
    +}
    +
    +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");
    diff --git a/drivers/pps/sysfs.c b/drivers/pps/sysfs.c
    new file mode 100644
    index 0000000..0520f62
    --- /dev/null
    +++ b/drivers/pps/sysfs.c
    @@ -0,0 +1,103 @@
    +/*
    + * sysfs.c -- sysfs support
    + *
    + *
    + * Copyright (C) 2007 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.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);
    +}
    +DEVICE_ATTR(assert, S_IRUGO, pps_show_assert, NULL);
    +
    +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);
    +}
    +DEVICE_ATTR(clear, S_IRUGO, pps_show_clear, NULL);
    +
    +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);
    +}
    +DEVICE_ATTR(mode, S_IRUGO, pps_show_mode, NULL);
    +
    +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);
    +}
    +DEVICE_ATTR(echo, S_IRUGO, pps_show_echo, NULL);
    +
    +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);
    +}
    +DEVICE_ATTR(name, S_IRUGO, pps_show_name, NULL);
    +
    +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);
    +}
    +DEVICE_ATTR(path, S_IRUGO, pps_show_path, NULL);
    +
    +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),
    +};
    diff --git a/include/linux/Kbuild b/include/linux/Kbuild
    index 9cdd12a..0dd702c 100644
    --- a/include/linux/Kbuild
    +++ b/include/linux/Kbuild
    @@ -294,6 +294,7 @@ 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 += qnx4_fs.h
    unifdef-y += quota.h
    diff --git a/include/linux/pps.h b/include/linux/pps.h
    new file mode 100644
    index 0000000..83a23d2
    --- /dev/null
    +++ b/include/linux/pps.h
    @@ -0,0 +1,202 @@
    +/*
    + * pps.h -- PPS API kernel header.
    + *
    + *
    + * Copyright (C) 2005-2007 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 "5.1.0"
    +#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
    + */
    +
    +#ifndef __KERNEL__
    +#include <linux/types.h>
    +#include <sys/time.h>
    +#include <sys/ioctl.h>
    +#else
    +#include <linux/time.h>
    +#endif
    +
    +#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_CHECK _IO('P', 0)
    +#define PPS_GETPARAMS _IOR('P', 1, struct pps_kparams *)
    +#define PPS_SETPARAMS _IOW('P', 2, struct pps_kparams *)
    +#define PPS_GETCAP _IOR('P', 3, int *)
    +#define PPS_FETCH _IOWR('P', 4, struct pps_fdata *)
    +
    +#ifdef __KERNEL__
    +
    +#include <linux/cdev.h>
    +#include <linux/device.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 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, int event, void *data);
    +
    +#endif /* __KERNEL__ */
    +
    +#endif /* _PPS_H_ */
    --
    1.5.4.3


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