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 <[EMAIL PROTECTED]> --- 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 <[EMAIL PROTECTED]> +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 <[EMAIL PROTECTED]> +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 <[EMAIL PROTECTED]> +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 <[EMAIL PROTECTED]> +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 <[EMAIL PROTECTED]> +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 <[EMAIL PROTECTED]> +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 <[EMAIL PROTECTED]> +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 <[EMAIL PROTECTED]> +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:[EMAIL PROTECTED]> '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 <[EMAIL PROTECTED]> + +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 f71f665..6dd0f35 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3150,6 +3150,13 @@ P: James Chapman M: [EMAIL PROTECTED] S: Maintained +PPS SUPPORT +P: Rodolfo Giometti +M: [EMAIL PROTECTED] +W: http://wiki.enneenne.com/index.php/LinuxPPS_support +L: [EMAIL PROTECTED] +S: Maintained + PREEMPTIBLE KERNEL P: Robert Love M: [EMAIL PROTECTED] 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 <[EMAIL PROTECTED]> + * + * 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 <[EMAIL PROTECTED]> + * + * 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 " + "<[EMAIL PROTECTED]>\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 <[EMAIL PROTECTED]>"); +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 <[EMAIL PROTECTED]> + * + * 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 <[EMAIL PROTECTED]> + * + * 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
