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Message-Id: <12048053473401-git-send-email-giometti@linux.it>
Date: Thu, 6 Mar 2008 13:09:00 +0100
From: Rodolfo Giometti <giometti@...ux.it>
To: linux-kernel@...r.kernel.org
Cc: Andrew Morton <akpm@...ux-foundation.org>,
David Woodhouse <dwmw2@...radead.org>,
Dave Jones <davej@...hat.com>, Sam Ravnborg <sam@...nborg.org>,
Greg KH <greg@...ah.com>,
Randy Dunlap <randy.dunlap@...cle.com>,
Rodolfo Giometti <giometti@...ux.it>
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@...ux.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 | 272 ++++++++++++++++++++++++++++
drivers/pps/pps.c | 342 +++++++++++++++++++++++++++++++++++
drivers/pps/sysfs.c | 130 +++++++++++++
include/linux/Kbuild | 1 +
include/linux/pps.h | 204 +++++++++++++++++++++
13 files changed, 1245 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..881b331
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-pps
@@ -0,0 +1,73 @@
+What: /sys/class/pps/
+Date: February 2008
+Contact: Rodolfo Giometti <giometti@...ux.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@...ux.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@...ux.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@...ux.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@...ux.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@...ux.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@...ux.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@...ux.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@...ux.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..c608aa8
--- /dev/null
+++ b/Documentation/pps/pps.txt
@@ -0,0 +1,170 @@
+
+ PPS - Pulse Per Second
+ ----------------------
+
+(C) Copyright 2007 Rodolfo Giometti <giometti@...eenne.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 fed09b5..40d51c2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3156,6 +3156,13 @@ P: James Chapman
M: jchapman@...alix.com
S: Maintained
+PPS SUPPORT
+P: Rodolfo Giometti
+M: giometti@...eenne.com
+W: http://wiki.enneenne.com/index.php/LinuxPPS_support
+L: linuxpps@...enneenne.com
+S: Maintained
+
PREEMPTIBLE KERNEL
P: Robert Love
M: rml@...h9.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..c127e66
--- /dev/null
+++ b/drivers/pps/kapi.c
@@ -0,0 +1,272 @@
+/*
+ * kapi.c -- kernel API
+ *
+ *
+ * Copyright (C) 2005-2007 Rodolfo Giometti <giometti@...ux.it>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+
+#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(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
+ */
+
+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(&idr_lock);
+ err = idr_get_new(&pps_idr, pps, &id);
+ spin_unlock_irq(&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, 0);
+ init_waitqueue_head(&pps->usage_queue);
+
+ /* 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;
+ }
+
+ /* Create the sysfs entry */
+ err = pps_sysfs_create_source_entry(pps);
+ if (err < 0) {
+ printk(KERN_ERR "pps: %s: unable to create sysfs entries\n",
+ info->name);
+ goto unregister_cdev;
+ }
+
+ pr_info("new PPS source %s at ID %d\n", info->name, id);
+
+ return id;
+
+unregister_cdev:
+ pps_unregister_cdev(pps);
+
+free_idr:
+ spin_lock_irq(&idr_lock);
+ idr_remove(&pps_idr, id);
+ spin_unlock_irq(&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);
+
+void pps_unregister_source(int source)
+{
+ struct pps_device *pps;
+
+ spin_lock_irq(&idr_lock);
+ pps = idr_find(&pps_idr, source);
+
+ if (!pps) {
+ spin_unlock_irq(&idr_lock);
+ return;
+ }
+
+ /* This should be done first in order to deny IRQ handlers
+ * to access PPS structs
+ */
+
+ idr_remove(&pps_idr, pps->id);
+ spin_unlock_irq(&idr_lock);
+
+ wait_event(pps->usage_queue, atomic_read(&pps->usage) == 0);
+
+ pps_sysfs_remove_source_entry(pps);
+ pps_unregister_cdev(pps);
+ kfree(pps);
+}
+EXPORT_SYMBOL(pps_unregister_source);
+
+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;
+ }
+
+ spin_lock_irqsave(&idr_lock, flags);
+ pps = idr_find(&pps_idr, source);
+
+ /* If we find a valid PPS source we lock it before leaving
+ * the lock!
+ */
+ if (pps)
+ atomic_inc(&pps->usage);
+ spin_unlock_irqrestore(&idr_lock, flags);
+
+ if (!pps)
+ return;
+
+ pr_debug("PPS event on source %d at %llu.%06u\n",
+ pps->id, 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 */
+ spin_lock_irqsave(&idr_lock, flags);
+ atomic_dec(&pps->usage);
+ wake_up_all(&pps->usage_queue);
+ spin_unlock_irqrestore(&idr_lock, flags);
+}
+EXPORT_SYMBOL(pps_event);
diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
new file mode 100644
index 0000000..53cce94
--- /dev/null
+++ b/drivers/pps/pps.c
@@ -0,0 +1,342 @@
+/*
+ * pps.c -- Main PPS support file
+ *
+ *
+ * Copyright (C) 2005-2007 Rodolfo Giometti <giometti@...ux.it>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+
+#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(¶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);
+
+ /* 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",
+ 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;
+
+ spin_lock_irq(&idr_lock);
+ found = idr_find(&pps_idr, pps->id) != NULL;
+
+ /* Lock the PPS source against (possible) deregistration */
+ if (found)
+ atomic_inc(&pps->usage);
+
+ spin_unlock_irq(&idr_lock);
+
+ 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 */
+ atomic_dec(&pps->usage);
+ wake_up_all(&pps->usage_queue);
+
+ 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;
+ }
+
+ 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@...ux.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@...ux.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..c25c91c
--- /dev/null
+++ b/drivers/pps/sysfs.c
@@ -0,0 +1,130 @@
+/*
+ * sysfs.c -- sysfs support
+ *
+ *
+ * Copyright (C) 2007 Rodolfo Giometti <giometti@...ux.it>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+
+#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",
+ 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",
+ 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);
+
+static struct attribute *pps_attrs[] = {
+ &dev_attr_mode.attr,
+ &dev_attr_echo.attr,
+ &dev_attr_name.attr,
+ &dev_attr_path.attr,
+ &dev_attr_assert.attr,
+ &dev_attr_clear.attr,
+ NULL
+};
+
+static struct attribute_group pps_group = {
+ .attrs = pps_attrs,
+};
+
+/*
+ * Public functions
+ */
+
+void pps_sysfs_remove_source_entry(struct pps_device *pps)
+{
+ /* Delete info files */
+ sysfs_remove_group(&pps->dev->kobj, &pps_group);
+}
+
+int pps_sysfs_create_source_entry(struct pps_device *pps)
+{
+ int ret;
+
+ /* Create info files */
+ ret = sysfs_create_group(&pps->dev->kobj, &pps_group);
+ if (ret)
+ dev_err(pps->dev, "unable to create default sysfs entries");
+
+ return 0;
+}
diff --git a/include/linux/Kbuild b/include/linux/Kbuild
index aada32f..c4cbd8d 100644
--- a/include/linux/Kbuild
+++ b/include/linux/Kbuild
@@ -297,6 +297,7 @@ 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..c455443
--- /dev/null
+++ b/include/linux/pps.h
@@ -0,0 +1,204 @@
+/*
+ * pps.h -- PPS API kernel header.
+ *
+ *
+ * Copyright (C) 2005-2007 Rodolfo Giometti <giometti@...ux.it>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+
+#ifndef _PPS_H_
+#define _PPS_H_
+
+/* 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>
+
+#define PPS_VERSION "5.0.0"
+#define PPS_MAX_SOURCES 16 /* should be enough... */
+
+/*
+ * 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 */
+ wait_queue_head_t usage_queue;
+
+ struct class class_dev;
+};
+
+/*
+ * Global variables
+ */
+
+extern spinlock_t idr_lock;
+extern struct idr pps_idr;
+
+/*
+ * Exported functions
+ */
+
+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);
+
+extern int pps_sysfs_create_source_entry(struct pps_device *pps);
+extern void pps_sysfs_remove_source_entry(struct pps_device *pps);
+
+#endif /* __KERNEL__ */
+
+#endif /* _PPS_H_ */
--
1.5.2.5
--
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