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This patch set adds the PPS support into Linux. PPS means "pulse per second" and its API is specified by RFC 2783 (Pulse-Per-Second API for UNIX-like Operating Systems, Version 1.0). The code has been tested with the NTPD program (http://www.eecis.udel.edu/~mills/ntp/html/index.html) and several GPS antennae. Changelog RESUBMIT 6 -> 7: * A new line discipline has been added in order to leave untouched the serial ports code (as suggested by Alan). * n_tty.c exports only GPL symbols. * ioctl numbers fixed in order to avoid any conflicts. * Last patch (0010-PPS-low-level-IRQ-timestamps-recording.patch) implements low level IRQs timestamps recording which mproves PPS precision but can be dropped for kernel inclusion! As suggested by Alan: "After that is sorted/merged we can come back to working out the best way to improve the IRQ and HARDPPS hacks." Rodolfo -- b/Documentation/ABI/testing/sysfs-pps | 73 +++++++ b/Documentation/ioctl-number.txt | 2 b/Documentation/pps/Makefile | 28 ++ b/Documentation/pps/pps.txt | 172 +++++++++++++++++ b/Documentation/pps/ppsfind | 17 + b/Documentation/pps/ppsldisc.c | 46 ++++ b/Documentation/pps/ppstest.c | 151 +++++++++++++++ b/Documentation/pps/timepps.h | 195 +++++++++++++++++++ b/Documentation/tty.txt | 4 b/MAINTAINERS | 7 b/arch/x86/kernel/irq_32.c | 17 + b/arch/x86/kernel/irq_64.c | 21 +- b/drivers/Kconfig | 2 b/drivers/Makefile | 1 b/drivers/char/lp.c | 61 ++++++ b/drivers/char/n_tty.c | 54 +++-- b/drivers/pps/Kconfig | 33 +++ b/drivers/pps/Makefile | 8 b/drivers/pps/clients/Kconfig | 18 + b/drivers/pps/clients/Makefile | 9 b/drivers/pps/clients/ktimer.c | 124 ++++++++++++ ...
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 | 172 ++++++++++++++++++ MAINTAINERS | 7 + drivers/Kconfig | 2 + drivers/Makefile | 1 + drivers/pps/Kconfig | 33 ++++ drivers/pps/Makefile | 8 + drivers/pps/kapi.c | 322 +++++++++++++++++++++++++++++++++ drivers/pps/pps.c | 335 +++++++++++++++++++++++++++++++++++ drivers/pps/sysfs.c | 104 +++++++++++ include/linux/Kbuild | 1 + include/linux/pps.h | 202 +++++++++++++++++++++ 13 files changed, 1262 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 ...
This patch adds into the PPS's documentation directory a possible
implementation of the PPS API (RFC 2783) by using the LinuxPPS's char
devices.
This file is not just an example but it can be used into real
systems. :)
Signed-off-by: Rodolfo Giometti <giometti@linux.it>
---
Documentation/pps/timepps.h | 195 +++++++++++++++++++++++++++++++++++++++++++
1 files changed, 195 insertions(+), 0 deletions(-)
create mode 100644 Documentation/pps/timepps.h
diff --git a/Documentation/pps/timepps.h b/Documentation/pps/timepps.h
new file mode 100644
index 0000000..2372949
--- /dev/null
+++ b/Documentation/pps/timepps.h
@@ -0,0 +1,195 @@
+/*
+ * timepps.h -- PPS API main 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 _SYS_TIMEPPS_H_
+#define _SYS_TIMEPPS_H_
+
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <errno.h>
+#include <linux/pps.h>
+
+#define LINUXPPS 1 /* signal we are using LinuxPPS */
+
+/*
+ * New data structures
+ */
+
+struct ntp_fp {
+ unsigned int integral;
+ unsigned int fractional;
+};
+
+union pps_timeu {
+ struct timespec tspec;
+ struct ntp_fp ntpfp;
+ unsigned long longpad[3];
+};
+
+struct pps_info {
+ unsigned long assert_sequence; /* seq. num. of ...Here some utilities and examples about the PPS API and the LinuxPPS
support.
* ppsldisc.c shows how to manage PPS line discipline;
* ppstest.c implements an useful testing program, while
* ppsfind tries to help the user into finding a specific PPS source by
using its name or path.
Signed-off-by: Rodolfo Giometti <giometti@linux.it>
---
Documentation/pps/Makefile | 28 ++++++++
Documentation/pps/ppsfind | 17 +++++
Documentation/pps/ppsldisc.c | 46 +++++++++++++
Documentation/pps/ppstest.c | 151 ++++++++++++++++++++++++++++++++++++++++++
4 files changed, 242 insertions(+), 0 deletions(-)
create mode 100644 Documentation/pps/Makefile
create mode 100644 Documentation/pps/ppsfind
create mode 100644 Documentation/pps/ppsldisc.c
create mode 100644 Documentation/pps/ppstest.c
diff --git a/Documentation/pps/Makefile b/Documentation/pps/Makefile
new file mode 100644
index 0000000..9841e6b
--- /dev/null
+++ b/Documentation/pps/Makefile
@@ -0,0 +1,28 @@
+TARGETS = ppstest ppsldisc
+
+CFLAGS += -Wall -O2 -D_GNU_SOURCE
+CFLAGS += -I .
+CFLAGS += -ggdb
+CFLAGS += -D__N_PPS=$(shell awk '/N_PPS/ {print $$3}' ../../include/linux/tty.h)
+
+# -- Actions section --
+
+.PHONY : all depend dep
+
+all : .depend $(TARGETS)
+
+.depend depend dep :
+ $(CC) $(CFLAGS) -M $(TARGETS:=.c) > .depend
+
+ifeq (.depend,$(wildcard .depend))
+include .depend
+endif
+
+
+# -- Clean section --
+
+.PHONY : clean
+
+clean :
+ rm -f *.o *~ core .depend
+ rm -f ${TARGETS}
diff --git a/Documentation/pps/ppsfind b/Documentation/pps/ppsfind
new file mode 100644
index 0000000..93c0e17
--- /dev/null
+++ b/Documentation/pps/ppsfind
@@ -0,0 +1,17 @@
+#!/bin/sh
+
+SYS="/sys/class/pps/"
+
+if [ $# -lt 1 ] ; then
+ echo "usage: ppsfind <name>" >&2
+ exit 1
+fi
+
+for d in $(ls $SYS) ; do
+ if grep $1 $SYS/$d/name >& /dev/null || \
+ grep $1 $SYS/$d/path >& /dev/null ; then
+ echo "$d: name=$(cat $SYS/$d/name) path=$(cat $SYS/$d/path)"
+ fi
+done
+
+exit ...Each PPS source can be registered/deregistered into the system by using special modules called "clients". They simply define the PPS sources' attributes and implement the time signal registartion mechanism. This patch adds a special directory for such clients and adds a dummy client that can be useful to test system integrity on real systems. Signed-off-by: Rodolfo Giometti <giometti@linux.it> --- drivers/pps/Kconfig | 2 + drivers/pps/Makefile | 1 + drivers/pps/clients/Kconfig | 18 ++++++ drivers/pps/clients/Makefile | 9 +++ drivers/pps/clients/ktimer.c | 124 ++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 154 insertions(+), 0 deletions(-) create mode 100644 drivers/pps/clients/Kconfig create mode 100644 drivers/pps/clients/Makefile create mode 100644 drivers/pps/clients/ktimer.c diff --git a/drivers/pps/Kconfig b/drivers/pps/Kconfig index cc2eb8e..1afe4e0 100644 --- a/drivers/pps/Kconfig +++ b/drivers/pps/Kconfig @@ -30,4 +30,6 @@ config PPS_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. +source drivers/pps/clients/Kconfig + endmenu diff --git a/drivers/pps/Makefile b/drivers/pps/Makefile index 19ea582..98960dd 100644 --- a/drivers/pps/Makefile +++ b/drivers/pps/Makefile @@ -4,5 +4,6 @@ pps_core-y := pps.o kapi.o sysfs.o obj-$(CONFIG_PPS) := pps_core.o +obj-y += clients/ ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG diff --git a/drivers/pps/clients/Kconfig b/drivers/pps/clients/Kconfig new file mode 100644 index 0000000..60b83be --- /dev/null +++ b/drivers/pps/clients/Kconfig @@ -0,0 +1,18 @@ +# +# PPS clients configuration +# + +if PPS + +comment "PPS clients support" + +config PPS_CLIENT_KTIMER + tristate "Kernel timer client (Testing client, use for debug)" + help + If you say yes here you get support for a PPS debugging client + which uses a kernel timer to generate the PPS ...
Signed-off-by: Rodolfo Giometti <giometti@linux.it>
---
Documentation/tty.txt | 4 ++++
include/linux/tty_ldisc.h | 8 ++++++++
2 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/Documentation/tty.txt b/Documentation/tty.txt
index 8e65c44..3fc812a 100644
--- a/Documentation/tty.txt
+++ b/Documentation/tty.txt
@@ -100,6 +100,10 @@ write_wakeup() - May be called at any point between open and close.
is permitted to call the driver write method from
this function. In such a situation defer it.
+dcd_change() - Report to the tty line the current DCD pin status
+ changes and the relative timestamp. The timestamp
+ can be NULL.
+
Driver Access
diff --git a/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h
index 40f38d8..526fbf4 100644
--- a/include/linux/tty_ldisc.h
+++ b/include/linux/tty_ldisc.h
@@ -99,6 +99,12 @@
* cease I/O to the tty driver. Can sleep. The driver should
* seek to perform this action quickly but should wait until
* any pending driver I/O is completed.
+ *
+ * void (*dcd_change)(struct tty_struct *tty, unsigned int status,
+ * struct timespec *ts)
+ *
+ * Tells the discipline that the DCD pin has changed its status and
+ * the relative timestamp. Pointer ts can be NULL.
*/
#include <linux/fs.h>
@@ -136,6 +142,8 @@ struct tty_ldisc_ops {
void (*receive_buf)(struct tty_struct *, const unsigned char *cp,
char *fp, int count);
void (*write_wakeup)(struct tty_struct *);
+ void (*dcd_change)(struct tty_struct *, unsigned int,
+ struct timespec *);
struct module *owner;
--
1.5.4.3
--
Signed-off-by: Rodolfo Giometti <giometti@linux.it>
---
drivers/char/n_tty.c | 54 +++++++++++++++++++++++++++++--------------------
include/linux/tty.h | 16 ++++++++++++++
2 files changed, 48 insertions(+), 22 deletions(-)
diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index 708c2b1..8458ded 100644
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -26,7 +26,7 @@
*
* 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to
* waiting writing processes-Sapan Bhatia <sapan@corewars.org>.
- * Also fixed a bug in BLOCKING mode where write_chan returns
+ * Also fixed a bug in BLOCKING mode where n_tty_write returns
* EAGAIN
*/
@@ -43,10 +43,10 @@
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/slab.h>
-#include <linux/poll.h>
#include <linux/bitops.h>
#include <linux/audit.h>
#include <linux/file.h>
+#include <linux/module.h>
#include <asm/uaccess.h>
#include <asm/system.h>
@@ -184,7 +184,7 @@ static void reset_buffer_flags(struct tty_struct *tty)
* Locking: ctrl_lock
*/
-static void n_tty_flush_buffer(struct tty_struct *tty)
+void n_tty_flush_buffer(struct tty_struct *tty)
{
unsigned long flags;
/* clear everything and unthrottle the driver */
@@ -200,6 +200,7 @@ static void n_tty_flush_buffer(struct tty_struct *tty)
}
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
}
+EXPORT_SYMBOL_GPL(n_tty_flush_buffer);
/**
* n_tty_chars_in_buffer - report available bytes
@@ -209,7 +210,7 @@ static void n_tty_flush_buffer(struct tty_struct *tty)
* at this instant in time.
*/
-static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
+ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
{
unsigned long flags;
ssize_t n = 0;
@@ -225,6 +226,7 @@ static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
spin_unlock_irqrestore(&tty->read_lock, flags);
return n;
}
+EXPORT_SYMBOL_GPL(n_tty_chars_in_buffer);
/**
* is_utf8_continuation - utf8 ...Add a new line discipline for "pulse per second" devices connected to a serial port. Signed-off-by: Rodolfo Giometti <giometti@linux.it> --- include/linux/tty.h | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/include/linux/tty.h b/include/linux/tty.h index 826d695..1857db2 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -24,7 +24,7 @@ */ #define NR_UNIX98_PTY_DEFAULT 4096 /* Default maximum for Unix98 ptys */ #define NR_UNIX98_PTY_MAX (1 << MINORBITS) /* Absolute limit */ -#define NR_LDISCS 18 +#define NR_LDISCS 19 /* line disciplines */ #define N_TTY 0 @@ -46,6 +46,7 @@ #define N_HCI 15 /* Bluetooth HCI UART */ #define N_GIGASET_M101 16 /* Siemens Gigaset M101 serial DECT adapter */ #define N_SLCAN 17 /* Serial / USB serial CAN Adaptors */ +#define N_PPS 18 /* Pulse per Second */ /* * This character is the same as _POSIX_VDISABLE: it cannot be used as -- 1.5.4.3 --
Adds support, by using the PPS line discipline, for the PPS sources connected with the CD (Carrier Detect) pin of a serial port. Signed-off-by: Rodolfo Giometti <giometti@linux.it> --- drivers/pps/clients/Kconfig | 7 ++ drivers/pps/clients/Makefile | 1 + drivers/pps/clients/pps-ldisc.c | 154 +++++++++++++++++++++++++++++++++++++++ drivers/serial/8250.c | 13 +++ include/linux/serial_core.h | 10 ++- 5 files changed, 184 insertions(+), 1 deletions(-) create mode 100644 drivers/pps/clients/pps-ldisc.c diff --git a/drivers/pps/clients/Kconfig b/drivers/pps/clients/Kconfig index 60b83be..487c1c8 100644 --- a/drivers/pps/clients/Kconfig +++ b/drivers/pps/clients/Kconfig @@ -15,4 +15,11 @@ config PPS_CLIENT_KTIMER This driver can also be built as a module. If so, the module will be called ktimer.ko. +config PPS_CLIENT_LDISC + tristate "PPS line discipline" + depends on PPS + help + If you say yes here you get support for a PPS source connected + with the CD (Carrier Detect) pin of your serial port. + endif diff --git a/drivers/pps/clients/Makefile b/drivers/pps/clients/Makefile index f3c1e39..9f5b988 100644 --- a/drivers/pps/clients/Makefile +++ b/drivers/pps/clients/Makefile @@ -3,6 +3,7 @@ # obj-$(CONFIG_PPS_CLIENT_KTIMER) += ktimer.o +obj-$(CONFIG_PPS_CLIENT_LDISC) += pps-ldisc.o ifeq ($(CONFIG_PPS_DEBUG),y) EXTRA_CFLAGS += -DDEBUG diff --git a/drivers/pps/clients/pps-ldisc.c b/drivers/pps/clients/pps-ldisc.c new file mode 100644 index 0000000..6484f17 --- /dev/null +++ b/drivers/pps/clients/pps-ldisc.c @@ -0,0 +1,154 @@ +/* + * pps-ldisc.c -- PPS line discipline + * + * + * Copyright (C) 2008 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. + ...
Adds support for the PPS sources connected with the interrupt pin of a
parallel port.
Signed-off-by: Rodolfo Giometti <giometti@linux.it>
---
drivers/char/lp.c | 61 +++++++++++++++++++++++++++++++++++++++++++
drivers/pps/clients/Kconfig | 10 +++++++
include/linux/parport.h | 22 +++++++++++++++
3 files changed, 93 insertions(+), 0 deletions(-)
diff --git a/drivers/char/lp.c b/drivers/char/lp.c
index 3f2719b..84e0bb0 100644
--- a/drivers/char/lp.c
+++ b/drivers/char/lp.c
@@ -760,6 +760,27 @@ static struct console lpcons = {
#endif /* console on line printer */
+/* Support for PPS signal on the line printer */
+
+#ifdef CONFIG_PPS_CLIENT_LP
+
+static void lp_pps_echo(int source, int event, void *data)
+{
+ struct parport *port = data;
+ unsigned char status = parport_read_status(port);
+
+ /* echo event via SEL bit */
+ parport_write_control(port,
+ parport_read_control(port) | PARPORT_CONTROL_SELECT);
+
+ /* signal no event */
+ if ((status & PARPORT_STATUS_ACK) != 0)
+ parport_write_control(port,
+ parport_read_control(port) & ~PARPORT_CONTROL_SELECT);
+}
+
+#endif
+
/* --- initialisation code ------------------------------------- */
static int parport_nr[LP_NO] = { [0 ... LP_NO-1] = LP_PARPORT_UNSPEC };
@@ -831,6 +852,38 @@ static int lp_register(int nr, struct parport *port)
}
#endif
+#ifdef CONFIG_PPS_CLIENT_LP
+ port->pps_info.owner = THIS_MODULE;
+ port->pps_info.dev = port->dev;
+ snprintf(port->pps_info.path, PPS_MAX_NAME_LEN, "/dev/lp%d", nr);
+
+ /* No PPS support if lp port has no IRQ line */
+ if (port->irq != PARPORT_IRQ_NONE) {
+ strncpy(port->pps_info.name, port->name, PPS_MAX_NAME_LEN);
+
+ port->pps_info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT | \
+ PPS_ECHOASSERT | \
+ PPS_CANWAIT | PPS_TSFMT_TSPEC;
+
+ port->pps_info.echo = lp_pps_echo;
+
+ port->pps_source = pps_register_source(&(port->pps_info),
+ PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
+ if (port->pps_source < ...Add low level IRQ timestamps recording for x86 (32 and 64 bits)
platforms and enable UART clients in order to use it.
This improves PPS precision. :)
Signed-off-by: Rodolfo Giometti <giometti@linux.it>
---
arch/x86/kernel/irq_32.c | 17 +++++++++++++++++
arch/x86/kernel/irq_64.c | 21 +++++++++++++++++++--
drivers/pps/Kconfig | 12 ++++++++++++
include/linux/pps.h | 1 +
include/linux/serial_core.h | 7 ++++++-
5 files changed, 55 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 1cf8c1f..85c3182 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -15,6 +15,7 @@
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/delay.h>
+#include <linux/pps.h>
#include <asm/apic.h>
#include <asm/uaccess.h>
@@ -25,6 +26,11 @@ EXPORT_PER_CPU_SYMBOL(irq_stat);
DEFINE_PER_CPU(struct pt_regs *, irq_regs);
EXPORT_PER_CPU_SYMBOL(irq_regs);
+#ifdef CONFIG_PPS_IRQ_EVENTS
+struct timespec pps_irq_ts[NR_IRQS];
+EXPORT_SYMBOL(pps_irq_ts);
+#endif
+
/*
* 'what should we do if we get a hw irq event on an illegal vector'.
* each architecture has to answer this themselves.
@@ -225,6 +231,12 @@ unsigned int do_IRQ(struct pt_regs *regs)
/* high bit used in ret_from_ code */
int overflow, irq = ~regs->orig_ax;
struct irq_desc *desc = irq_desc + irq;
+#ifdef CONFIG_PPS_IRQ_EVENTS
+ struct timespec ts;
+
+ /* Get IRQ timestamps as soon as possible for the PPS layer */
+ getnstimeofday(&ts);
+#endif
if (unlikely((unsigned)irq >= NR_IRQS)) {
printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
@@ -232,6 +244,11 @@ unsigned int do_IRQ(struct pt_regs *regs)
BUG();
}
+#ifdef CONFIG_PPS_IRQ_EVENTS
+ /* Then, after sanity check, store the IRQ timestamp */
+ pps_irq_ts[irq] = ts;
+#endif
+
old_regs = set_irq_regs(regs);
irq_enter();
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index 1f78b23..e9184ce 100644
--- ...
