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.
Rodolfo
--
Documentation/pps/Makefile | 2
b/Documentation/ABI/testing/sysfs-pps | 73 +++++++
b/Documentation/ioctl-number.txt | 2
b/Documentation/pps/Makefile | 27 ++
b/Documentation/pps/pps.txt | 170 ++++++++++++++++
b/Documentation/pps/ppsctl.c | 63 ++++++
b/Documentation/pps/ppsfind | 17 +
b/Documentation/pps/ppstest.c | 152 +++++++++++++++
b/Documentation/pps/timepps.h | 196 +++++++++++++++++++
b/MAINTAINERS | 7
b/drivers/Kconfig | 2
b/drivers/Makefile | 1
b/drivers/char/lp.c | 61 ++++++
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 | 115 +++++++++++
b/drivers/pps/kapi.c | 272 +++++++++++++++++++++++++++
b/drivers/pps/pps.c | 342 ++++++++++++++++++++++++++++++++++
b/drivers/pps/sysfs.c | 130 ++++++++++++
b/drivers/serial/8250.c | 2
b/drivers/serial/serial_core.c | 71 ++++++-
b/include/linux/Kbuild | 1
b/include/linux/parport.h | 13 +
b/include/linux/pps.h | 205 ++++++++++++++++++++
b/include/linux/serial_core.h | 31 ++-
drivers/pps/Kconfig | 2
drivers/pps/Makefile | 1
drivers/pps/clients/Kconfig | 20 +
30 files changed, 2031 insertions(+), 15 deletions(-)
Signed-off-by: Rodolfo Giometti <[email protected]>
---
Documentation/pps/Makefile | 2 +-
Documentation/pps/ppsctl.c | 62 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 63 insertions(+), 1 deletions(-)
create mode 100644 Documentation/pps/ppsctl.c
diff --git a/Documentation/pps/Makefile b/Documentation/pps/Makefile
index af4f9b4..8ef4f47 100644
--- a/Documentation/pps/Makefile
+++ b/Documentation/pps/Makefile
@@ -1,4 +1,4 @@
-TARGETS = ppstest
+TARGETS = ppstest ppsctl
CFLAGS += -Wall -O2 -D_GNU_SOURCE
CFLAGS += -I .
diff --git a/Documentation/pps/ppsctl.c b/Documentation/pps/ppsctl.c
new file mode 100644
index 0000000..83fd08a
--- /dev/null
+++ b/Documentation/pps/ppsctl.c
@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+#include <linux/serial.h>
+
+void usage(char *name)
+{
+ fprintf(stderr, "usage: %s <ttyS> [enable|disable]\n", name);
+
+ exit(EXIT_FAILURE);
+}
+
+int main(int argc, char *argv[])
+{
+ int fd;
+ int ret;
+ struct serial_struct ss;
+
+ if (argc < 2)
+ usage(argv[0]);
+
+ fd = open(argv[1], O_RDWR);
+ if (fd < 0) {
+ perror("open");
+ exit(EXIT_FAILURE);
+ }
+
+ ret = ioctl(fd, TIOCGSERIAL, &ss);
+ if (ret < 0) {
+ perror("ioctl(TIOCGSERIAL)");
+ exit(EXIT_FAILURE);
+ }
+
+ if (argc < 3) { /* just read PPS status */
+ printf("PPS is %sabled\n",
+ ss.flags & ASYNC_HARDPPS_CD ? "en" : "dis");
+ exit(EXIT_SUCCESS);
+ }
+
+ if (argv[2][0] == 'e' || argv[2][0] == '1')
+ ss.flags |= ASYNC_HARDPPS_CD;
+ else if (argv[2][0] == 'd' || argv[2][0] == '0')
+ ss.flags &= ~ASYNC_HARDPPS_CD;
+ else {
+ fprintf(stderr, "invalid state argument \"%s\"\n", argv[2]);
+ exit(EXIT_FAILURE);
+ }
+
+ ret = ioctl(fd, TIOCSSERIAL, &ss);
+ if (ret < 0) {
+ perror("ioctl(TIOCSSERIAL)");
+ exit(EXIT_FAILURE);
+ }
+
+ return 0;
+}
--
1.5.2.5
Adds support for the PPS sources connected with the CD (Carrier
Detect) pin of a serial port.
Signed-off-by: Rodolfo Giometti <[email protected]>
---
drivers/pps/clients/Kconfig | 10 ++++++
drivers/serial/8250.c | 2 +
drivers/serial/serial_core.c | 71 +++++++++++++++++++++++++++++++++++++++++-
include/linux/serial_core.h | 30 ++++++++++++++---
4 files changed, 106 insertions(+), 7 deletions(-)
diff --git a/drivers/pps/clients/Kconfig b/drivers/pps/clients/Kconfig
index 60b83be..517c338 100644
--- a/drivers/pps/clients/Kconfig
+++ b/drivers/pps/clients/Kconfig
@@ -15,4 +15,14 @@ config PPS_CLIENT_KTIMER
This driver can also be built as a module. If so, the module
will be called ktimer.ko.
+comment "UART serial support (forced off)"
+ depends on ! (SERIAL_CORE != n && !(PPS = m && SERIAL_CORE = y))
+
+config PPS_CLIENT_UART
+ bool "UART serial support"
+ depends on SERIAL_CORE != n && !(PPS = m && SERIAL_CORE = y)
+ 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/serial/8250.c b/drivers/serial/8250.c
index 77f7a7f..880cbeb 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -2119,6 +2119,8 @@ serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
up->ier |= UART_IER_MSI;
if (up->capabilities & UART_CAP_UUE)
up->ier |= UART_IER_UUE | UART_IER_RTOIE;
+ if (up->port.flags & UPF_HARDPPS_CD)
+ up->ier |= UART_IER_MSI; /* enable interrupts */
serial_out(up, UART_IER, up->ier);
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 0f5a179..e35fbef 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -33,6 +33,7 @@
#include <linux/serial.h> /* for serial_state and serial_icounter_struct */
#include <linux/delay.h>
#include <linux/mutex.h>
+#include <linux/pps.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
@@ -635,6 +636,54 @@ static int uart_get_info(struct uart_state *state,
return 0;
}
+#ifdef CONFIG_PPS_CLIENT_UART
+
+static int
+uart_register_pps_port(struct uart_state *state, struct uart_port *port)
+{
+ struct tty_driver *drv = port->info->tty->driver;
+ int ret;
+
+ state->pps_info.owner = THIS_MODULE;
+ state->pps_info.dev = port->dev;
+ snprintf(state->pps_info.name, PPS_MAX_NAME_LEN, "%s%d",
+ drv->driver_name, port->line);
+ snprintf(state->pps_info.path, PPS_MAX_NAME_LEN, "/dev/%s%d",
+ drv->name, port->line);
+
+ state->pps_info.mode = PPS_CAPTUREBOTH | \
+ PPS_OFFSETASSERT | PPS_OFFSETCLEAR | \
+ PPS_CANWAIT | PPS_TSFMT_TSPEC;
+
+ ret = pps_register_source(&state->pps_info, PPS_CAPTUREBOTH | \
+ PPS_OFFSETASSERT | PPS_OFFSETCLEAR);
+ if (ret < 0) {
+ dev_err(port->dev, "cannot register PPS source \"%s\"\n",
+ state->pps_info.path);
+ return ret;
+ }
+ port->pps_source = ret;
+ dev_dbg(port->dev, "PPS source #%d \"%s\" added\n",
+ port->pps_source, state->pps_info.path);
+
+ return 0;
+}
+
+static void
+uart_unregister_pps_port(struct uart_state *state, struct uart_port *port)
+{
+ pps_unregister_source(port->pps_source);
+ dev_dbg(port->dev, "PPS source #%d \"%s\" removed\n",
+ port->pps_source, state->pps_info.path);
+}
+
+#else
+
+#define uart_register_pps_port(state, port) do { } while (0)
+#define uart_unregister_pps_port(state, port) do { } while (0)
+
+#endif /* CONFIG_PPS_CLIENT_UART */
+
static int uart_set_info(struct uart_state *state,
struct serial_struct __user *newinfo)
{
@@ -810,11 +859,19 @@ static int uart_set_info(struct uart_state *state,
(port->flags & UPF_LOW_LATENCY) ? 1 : 0;
check_and_exit:
+ /* PPS support enabled/disabled? */
+ if ((old_flags & UPF_HARDPPS_CD) != (new_flags & UPF_HARDPPS_CD)) {
+ if (new_flags & UPF_HARDPPS_CD)
+ uart_register_pps_port(state, port);
+ else
+ uart_unregister_pps_port(state, port);
+ }
+
retval = 0;
if (port->type == PORT_UNKNOWN)
goto exit;
if (state->info->flags & UIF_INITIALIZED) {
- if (((old_flags ^ port->flags) & UPF_SPD_MASK) ||
+ if (((old_flags ^ port->flags) & (UPF_SPD_MASK|UPF_HARDPPS_CD)) ||
old_custom_divisor != port->custom_divisor) {
/*
* If they're setting up a custom divisor or speed,
@@ -2148,6 +2205,12 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
port->ops->config_port(port, flags);
}
+ /*
+ * Add the PPS support for the current port.
+ */
+ if (port->flags & UPF_HARDPPS_CD)
+ uart_register_pps_port(state, port);
+
if (port->type != PORT_UNKNOWN) {
unsigned long flags;
@@ -2405,6 +2468,12 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *port)
mutex_unlock(&state->mutex);
/*
+ * Remove PPS support from the current port.
+ */
+ if (port->flags & UPF_HARDPPS_CD)
+ uart_unregister_pps_port(state, port);
+
+ /*
* Remove the devices from the tty layer
*/
tty_unregister_device(drv->tty_driver, port->line);
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 289942f..0f8fbd4 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -166,6 +166,7 @@
#include <linux/tty.h>
#include <linux/mutex.h>
#include <linux/sysrq.h>
+#include <linux/pps.h>
struct uart_port;
struct uart_info;
@@ -245,6 +246,9 @@ struct uart_port {
unsigned char regshift; /* reg offset shift */
unsigned char iotype; /* io access style */
unsigned char unused1;
+#ifdef CONFIG_PPS_CLIENT_UART
+ int pps_source; /* PPS source ID */
+#endif
#define UPIO_PORT (0)
#define UPIO_HUB6 (1)
@@ -289,7 +293,8 @@ struct uart_port {
#define UPF_IOREMAP ((__force upf_t) (1 << 31))
#define UPF_CHANGE_MASK ((__force upf_t) (0x17fff))
-#define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
+#define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY\
+ |UPF_HARDPPS_CD))
unsigned int mctrl; /* current modem ctrl settings */
unsigned int timeout; /* character-based timeout */
@@ -322,6 +327,10 @@ struct uart_state {
struct uart_info *info;
struct uart_port *port;
+#ifdef CONFIG_PPS_CLIENT_UART
+ struct pps_source_info pps_info;
+#endif
+
struct mutex mutex;
};
@@ -486,13 +495,22 @@ uart_handle_dcd_change(struct uart_port *port, unsigned int status)
{
struct uart_info *info = port->info;
- port->icount.dcd++;
-
-#ifdef CONFIG_HARD_PPS
- if ((port->flags & UPF_HARDPPS_CD) && status)
- hardpps();
+#ifdef CONFIG_PPS_CLIENT_UART
+ if (port->flags & UPF_HARDPPS_CD) {
+ if (status) {
+ pps_event(port->pps_source, PPS_CAPTUREASSERT, port);
+ dev_dbg(port->dev, "PPS assert at %lu on source #%d\n",
+ jiffies, port->pps_source);
+ } else {
+ pps_event(port->pps_source, PPS_CAPTURECLEAR, port);
+ dev_dbg(port->dev, "PPS clear at %lu on source #%d\n",
+ jiffies, port->pps_source);
+ }
+ }
#endif
+ port->icount.dcd++;
+
if (info->flags & UIF_CHECK_CD) {
if (status)
wake_up_interruptible(&info->open_wait);
--
1.5.2.5
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 <[email protected]>
---
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 <[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 _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 assert event */
+ unsigned long clear_sequence; /* seq. num. of clear event */
+ union pps_timeu assert_tu; /* time of assert event */
+ union pps_timeu clear_tu; /* time of clear event */
+ int current_mode; /* current mode bits */
+};
+
+struct pps_params {
+ int api_version; /* API version # */
+ int mode; /* mode bits */
+ union pps_timeu assert_off_tu; /* offset compensation for assert */
+ union pps_timeu clear_off_tu; /* offset compensation for clear */
+};
+
+typedef int pps_handle_t; /* represents a PPS source */
+typedef unsigned long pps_seq_t; /* sequence number */
+typedef struct ntp_fp ntp_fp_t; /* NTP-compatible time stamp */
+typedef union pps_timeu pps_timeu_t; /* generic data type for time stamps */
+typedef struct pps_info pps_info_t;
+typedef struct pps_params pps_params_t;
+
+#define assert_timestamp assert_tu.tspec
+#define clear_timestamp clear_tu.tspec
+
+#define assert_timestamp_ntpfp assert_tu.ntpfp
+#define clear_timestamp_ntpfp clear_tu.ntpfp
+
+#define assert_offset assert_off_tu.tspec
+#define clear_offset clear_off_tu.tspec
+
+#define assert_offset_ntpfp assert_off_tu.ntpfp
+#define clear_offset_ntpfp clear_off_tu.ntpfp
+
+/*
+ * The PPS API
+ */
+
+static __inline int time_pps_create(int source, pps_handle_t *handle)
+{
+ int ret;
+
+ if (!handle) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ /* First we check if current device is a PPS valid PPS one...
+ */
+ ret = ioctl(source, PPS_CHECK);
+ if (ret) {
+ errno = EOPNOTSUPP;
+ return -1;
+ }
+
+ /* ... then since in LinuxPPS there are no differences between a
+ * "PPS source" and a "PPS handle", we simply return the same value.
+ */
+ *handle = source;
+
+ return 0;
+}
+
+static __inline int time_pps_destroy(pps_handle_t handle)
+{
+ return close(handle);
+}
+
+static __inline int time_pps_getparams(pps_handle_t handle,
+ pps_params_t *ppsparams)
+{
+ int ret;
+ struct pps_kparams __ppsparams;
+
+ ret = ioctl(handle, PPS_GETPARAMS, &__ppsparams);
+
+ ppsparams->api_version = __ppsparams.api_version;
+ ppsparams->mode = __ppsparams.mode;
+ ppsparams->assert_off_tu.tspec.tv_sec = __ppsparams.assert_off_tu.sec;
+ ppsparams->assert_off_tu.tspec.tv_nsec = __ppsparams.assert_off_tu.nsec;
+ ppsparams->clear_off_tu.tspec.tv_sec = __ppsparams.clear_off_tu.sec;
+ ppsparams->clear_off_tu.tspec.tv_nsec = __ppsparams.clear_off_tu.nsec;
+
+ return ret;
+}
+
+static __inline int time_pps_setparams(pps_handle_t handle,
+ const pps_params_t *ppsparams)
+{
+ struct pps_kparams __ppsparams;
+
+ __ppsparams.api_version = ppsparams->api_version;
+ __ppsparams.mode = ppsparams->mode;
+ __ppsparams.assert_off_tu.sec = ppsparams->assert_off_tu.tspec.tv_sec;
+ __ppsparams.assert_off_tu.nsec = ppsparams->assert_off_tu.tspec.tv_nsec;
+ __ppsparams.clear_off_tu.sec = ppsparams->clear_off_tu.tspec.tv_sec;
+ __ppsparams.clear_off_tu.nsec = ppsparams->clear_off_tu.tspec.tv_nsec;
+
+ return ioctl(handle, PPS_SETPARAMS, &__ppsparams);
+}
+
+/* Get capabilities for handle */
+static __inline int time_pps_getcap(pps_handle_t handle, int *mode)
+{
+ return ioctl(handle, PPS_GETCAP, mode);
+}
+
+static __inline int time_pps_fetch(pps_handle_t handle, const int tsformat,
+ pps_info_t *ppsinfobuf,
+ const struct timespec *timeout)
+{
+ struct pps_fdata __fdata;
+ int ret;
+
+ /* Sanity checks */
+ if (tsformat != PPS_TSFMT_TSPEC) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ if (timeout) {
+ __fdata.timeout.sec = timeout->tv_sec;
+ __fdata.timeout.nsec = timeout->tv_nsec;
+ __fdata.timeout.flags = ~PPS_TIME_INVALID;
+ } else
+ __fdata.timeout.flags = PPS_TIME_INVALID;
+
+ ret = ioctl(handle, PPS_FETCH, &__fdata);
+
+ ppsinfobuf->assert_sequence = __fdata.info.assert_sequence;
+ ppsinfobuf->clear_sequence = __fdata.info.clear_sequence;
+ ppsinfobuf->assert_tu.tspec.tv_sec = __fdata.info.assert_tu.sec;
+ ppsinfobuf->assert_tu.tspec.tv_nsec = __fdata.info.assert_tu.nsec;
+ ppsinfobuf->clear_tu.tspec.tv_sec = __fdata.info.clear_tu.sec;
+ ppsinfobuf->clear_tu.tspec.tv_nsec = __fdata.info.clear_tu.nsec;
+ ppsinfobuf->current_mode = __fdata.info.current_mode;
+
+ return ret;
+}
+
+static __inline int time_pps_kcbind(pps_handle_t handle,
+ const int kernel_consumer,
+ const int edge, const int tsformat)
+{
+ /* LinuxPPS doesn't implement kernel consumer feature */
+ errno = EOPNOTSUPP;
+ return -1;
+}
+
+#endif /* _SYS_TIMEPPS_H_ */
--
1.5.2.5
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 fed09b5..40d51c2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3156,6 +3156,13 @@ 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
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 <[email protected]>
---
drivers/pps/Kconfig | 2 +
drivers/pps/Makefile | 1 +
drivers/pps/clients/Kconfig | 18 +++++++
drivers/pps/clients/Makefile | 9 +++
drivers/pps/clients/ktimer.c | 114 ++++++++++++++++++++++++++++++++++++++++++
5 files changed, 144 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-$(CONFIG_PPS_DEBUG) := -DDEBUG
diff --git a/drivers/pps/clients/Kconfig b/drivers/pps/clients/Kconfig
new file mode 100644
index 0000000..60b83be
--- /dev/null
+++ b/drivers/pps/clients/Kconfig
@@ -0,0 +1,18 @@
+#
+# PPS clients configuration
+#
+
+if PPS
+
+comment "PPS clients support"
+
+config PPS_CLIENT_KTIMER
+ tristate "Kernel timer client (Testing client, use for debug)"
+ help
+ If you say yes here you get support for a PPS debugging client
+ which uses a kernel timer to generate the PPS signal.
+
+ This driver can also be built as a module. If so, the module
+ will be called ktimer.ko.
+
+endif
diff --git a/drivers/pps/clients/Makefile b/drivers/pps/clients/Makefile
new file mode 100644
index 0000000..f3c1e39
--- /dev/null
+++ b/drivers/pps/clients/Makefile
@@ -0,0 +1,9 @@
+#
+# Makefile for PPS clients.
+#
+
+obj-$(CONFIG_PPS_CLIENT_KTIMER) += ktimer.o
+
+ifeq ($(CONFIG_PPS_DEBUG),y)
+EXTRA_CFLAGS += -DDEBUG
+endif
diff --git a/drivers/pps/clients/ktimer.c b/drivers/pps/clients/ktimer.c
new file mode 100644
index 0000000..5845188
--- /dev/null
+++ b/drivers/pps/clients/ktimer.c
@@ -0,0 +1,114 @@
+/*
+ * ktimer.c -- kernel timer test client
+ *
+ *
+ * Copyright (C) 2005-2006 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/time.h>
+#include <linux/timer.h>
+
+#include <linux/pps.h>
+
+/*
+ * Global variables
+ */
+
+static int source;
+static struct timer_list ktimer;
+
+/*
+ * The kernel timer
+ */
+
+static void pps_ktimer_event(unsigned long ptr)
+{
+ pr_info("PPS event at %lu\n", jiffies);
+
+ pps_event(source, PPS_CAPTUREASSERT, NULL);
+
+ mod_timer(&ktimer, jiffies + HZ);
+}
+
+/*
+ * The echo function
+ */
+
+static void pps_ktimer_echo(int source, int event, void *data)
+{
+ pr_info("echo %s %s for source %d\n",
+ event & PPS_CAPTUREASSERT ? "assert" : "",
+ event & PPS_CAPTURECLEAR ? "clear" : "",
+ source);
+}
+
+/*
+ * The PPS info struct
+ */
+
+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,
+};
+
+/*
+ * Module staff
+ */
+
+static void __exit pps_ktimer_exit(void)
+{
+ del_timer_sync(&ktimer);
+ pps_unregister_source(source);
+
+ pr_info("ktimer PPS source unregistered\n");
+}
+
+static int __init pps_ktimer_init(void)
+{
+ int ret;
+
+ ret = pps_register_source(&pps_ktimer_info,
+ PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
+ if (ret < 0) {
+ printk(KERN_ERR "cannot register ktimer source\n");
+ return ret;
+ }
+ source = ret;
+
+ setup_timer(&ktimer, pps_ktimer_event, 0);
+ mod_timer(&ktimer, jiffies + HZ);
+
+ pr_info("ktimer PPS source registered at %d\n", source);
+
+ return 0;
+}
+
+module_init(pps_ktimer_init);
+module_exit(pps_ktimer_exit);
+
+MODULE_AUTHOR("Rodolfo Giometti <[email protected]>");
+MODULE_DESCRIPTION("dummy PPS source by using a kernel timer (just for debug)");
+MODULE_LICENSE("GPL");
--
1.5.2.5
Adds support for the PPS sources connected with the interrupt pin of a
parallel port.
Signed-off-by: Rodolfo Giometti <[email protected]>
---
drivers/char/lp.c | 61 +++++++++++++++++++++++++++++++++++++++++++
drivers/pps/clients/Kconfig | 10 +++++++
include/linux/parport.h | 12 ++++++++
3 files changed, 83 insertions(+), 0 deletions(-)
diff --git a/drivers/char/lp.c b/drivers/char/lp.c
index 60ac642..b201fed 100644
--- a/drivers/char/lp.c
+++ b/drivers/char/lp.c
@@ -746,6 +746,27 @@ 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 };
@@ -816,6 +837,38 @@ 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 < 0)
+ dev_err(port->dev,
+ "cannot register PPS source \"%s\"\n",
+ port->pps_info.path);
+ else
+ dev_info(port->dev, "PPS source #%d \"%s\" added\n",
+ port->pps_source, port->pps_info.path);
+ } else {
+ port->pps_source = -1;
+ dev_err(port->dev, "PPS support disabled because port \"%s\" "
+ "is in polling mode\n",
+ port->pps_info.path);
+ }
+#endif
+
return 0;
}
@@ -858,6 +911,14 @@ static void lp_detach (struct parport *port)
console_registered = NULL;
}
#endif /* CONFIG_LP_CONSOLE */
+
+#ifdef CONFIG_PPS_CLIENT_LP
+ if (port->pps_source >= 0) {
+ pps_unregister_source(port->pps_source);
+ dev_dbg(port->dev, "PPS source #%d \"%s\" removed\n",
+ port->pps_source, port->pps_info.path);
+ }
+#endif
}
static struct parport_driver lp_driver = {
diff --git a/drivers/pps/clients/Kconfig b/drivers/pps/clients/Kconfig
index 517c338..09ba5c3 100644
--- a/drivers/pps/clients/Kconfig
+++ b/drivers/pps/clients/Kconfig
@@ -25,4 +25,14 @@ config PPS_CLIENT_UART
If you say yes here you get support for a PPS source connected
with the CD (Carrier Detect) pin of your serial port.
+comment "Parallel printer support (forced off)"
+ depends on !( PRINTER != n && !(PPS = m && PRINTER = y))
+
+config PPS_CLIENT_LP
+ bool "Parallel printer support"
+ depends on PRINTER != n && !(PPS = m && PRINTER = y)
+ help
+ If you say yes here you get support for a PPS source connected
+ with the interrupt pin of your parallel port.
+
endif
diff --git a/include/linux/parport.h b/include/linux/parport.h
index d1ad546..501a9dc 100644
--- a/include/linux/parport.h
+++ b/include/linux/parport.h
@@ -100,6 +100,7 @@ typedef enum {
#include <linux/proc_fs.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
+#include <linux/pps.h>
#include <linux/irqreturn.h>
#include <asm/system.h>
#include <asm/ptrace.h>
@@ -328,6 +329,11 @@ struct parport {
struct list_head full_list;
struct parport *slaves[3];
+
+#ifdef CONFIG_PPS_CLIENT_LP
+ struct pps_source_info pps_info;
+ int pps_source; /* PPS source ID */
+#endif
};
#define DEFAULT_SPIN_TIME 500 /* us */
@@ -516,6 +522,12 @@ extern int parport_daisy_select (struct parport *port, int daisy, int mode);
/* Lowlevel drivers _can_ call this support function to handle irqs. */
static inline void parport_generic_irq(struct parport *port)
{
+#ifdef CONFIG_PPS_CLIENT_LP
+ pps_event(port->pps_source, PPS_CAPTUREASSERT, port);
+ dev_dbg(port->dev, "PPS assert at %lu on source #%d\n",
+ jiffies, port->pps_source);
+#endif
+
parport_ieee1284_interrupt (port);
read_lock(&port->cad_lock);
if (port->cad && port->cad->irq_func)
--
1.5.2.5
Here some utilities and examples about the PPS API and the LinuxPPS
support.
* 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 <[email protected]>
---
Documentation/pps/Makefile | 27 ++++++++
Documentation/pps/ppsfind | 17 +++++
Documentation/pps/ppstest.c | 151 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 195 insertions(+), 0 deletions(-)
create mode 100644 Documentation/pps/Makefile
create mode 100644 Documentation/pps/ppsfind
create mode 100644 Documentation/pps/ppstest.c
diff --git a/Documentation/pps/Makefile b/Documentation/pps/Makefile
new file mode 100644
index 0000000..af4f9b4
--- /dev/null
+++ b/Documentation/pps/Makefile
@@ -0,0 +1,27 @@
+TARGETS = ppstest
+
+CFLAGS += -Wall -O2 -D_GNU_SOURCE
+CFLAGS += -I .
+CFLAGS += -ggdb
+
+# -- 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 0
diff --git a/Documentation/pps/ppstest.c b/Documentation/pps/ppstest.c
new file mode 100644
index 0000000..d125ffa
--- /dev/null
+++ b/Documentation/pps/ppstest.c
@@ -0,0 +1,151 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include <timepps.h>
+
+int find_source(char *path, pps_handle_t *handle, int *avail_mode)
+{
+ pps_params_t params;
+ int ret;
+
+ printf("trying PPS source \"%s\"\n", path);
+
+ /* Try to find the source by using the supplied "path" name */
+ ret = open(path, O_RDWR);
+ if (ret < 0) {
+ fprintf(stderr, "unable to open device \"%s\" (%m)\n", path);
+ return ret;
+ }
+
+ /* Open the PPS source (and check the file descriptor) */
+ ret = time_pps_create(ret, handle);
+ if (ret < 0) {
+ fprintf(stderr, "cannot create a PPS source from device "
+ "\"%s\" (%m)\n", path);
+ return -1;
+ }
+ printf("found PPS source \"%s\"\n", path);
+
+ /* Find out what features are supported */
+ ret = time_pps_getcap(*handle, avail_mode);
+ if (ret < 0) {
+ fprintf(stderr, "cannot get capabilities (%m)\n");
+ return -1;
+ }
+ if ((*avail_mode & PPS_CAPTUREASSERT) == 0) {
+ fprintf(stderr, "cannot CAPTUREASSERT\n");
+ return -1;
+ }
+ if ((*avail_mode & PPS_OFFSETASSERT) == 0) {
+ fprintf(stderr, "cannot OFFSETASSERT\n");
+ return -1;
+ }
+
+ /* Capture assert timestamps, and compensate for a 675 nsec
+ * propagation delay */
+ ret = time_pps_getparams(*handle, ¶ms);
+ if (ret < 0) {
+ fprintf(stderr, "cannot get parameters (%m)\n");
+ return -1;
+ }
+ params.assert_offset.tv_sec = 0;
+ params.assert_offset.tv_nsec = 675;
+ params.mode |= PPS_CAPTUREASSERT | PPS_OFFSETASSERT;
+ ret = time_pps_setparams(*handle, ¶ms);
+ if (ret < 0) {
+ fprintf(stderr, "cannot set parameters (%m)\n");
+ return -1;
+ }
+
+ return 0;
+}
+
+int fetch_source(int i, pps_handle_t *handle, int *avail_mode)
+{
+ struct timespec timeout;
+ pps_info_t infobuf;
+ int ret;
+
+ /* create a zero-valued timeout */
+ timeout.tv_sec = 3;
+ timeout.tv_nsec = 0;
+
+retry:
+ if (*avail_mode & PPS_CANWAIT) /* waits for the next event */
+ ret = time_pps_fetch(*handle, PPS_TSFMT_TSPEC, &infobuf,
+ &timeout);
+ else {
+ sleep(1);
+ ret = time_pps_fetch(*handle, PPS_TSFMT_TSPEC, &infobuf,
+ &timeout);
+ }
+ if (ret < 0) {
+ if (ret == -EINTR) {
+ fprintf(stderr, "time_pps_fetch() got a signal!\n");
+ goto retry;
+ }
+
+ fprintf(stderr, "time_pps_fetch() error %d (%m)\n", ret);
+ return -1;
+ }
+
+ printf("source %d - "
+ "assert %ld.%09ld, sequence: %ld - "
+ "clear %ld.%09ld, sequence: %ld\n",
+ i,
+ infobuf.assert_timestamp.tv_sec,
+ infobuf.assert_timestamp.tv_nsec,
+ infobuf.assert_sequence,
+ infobuf.clear_timestamp.tv_sec,
+ infobuf.clear_timestamp.tv_nsec, infobuf.clear_sequence);
+
+ return 0;
+}
+
+void usage(char *name)
+{
+ fprintf(stderr, "usage: %s <ppsdev> [<ppsdev> ...]\n", name);
+ exit(EXIT_FAILURE);
+}
+
+int main(int argc, char *argv[])
+{
+ int num;
+ pps_handle_t handle[4];
+ int avail_mode[4];
+ int i = 0;
+ int ret;
+
+ /* Check the command line */
+ if (argc < 2)
+ usage(argv[0]);
+
+ for (i = 1; i < argc && i <= 4; i++) {
+ ret = find_source(argv[i], &handle[i - 1], &avail_mode[i - 1]);
+ if (ret < 0)
+ exit(EXIT_FAILURE);
+ }
+
+ num = i - 1;
+ printf("ok, found %d source(s), now start fetching data...\n", num);
+
+ /* loop, printing the most recent timestamp every second or so */
+ while (1) {
+ for (i = 0; i < num; i++) {
+ ret = fetch_source(i, &handle[i], &avail_mode[i]);
+ if (ret < 0 && errno != ETIMEDOUT)
+ exit(EXIT_FAILURE);
+ }
+ }
+
+ for (; i >= 0; i--)
+ time_pps_destroy(handle[i]);
+
+ return 0;
+}
--
1.5.2.5
On Thu, Mar 6, 2008 at 5:08 AM, Rodolfo Giometti <[email protected]> wrote:
> 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.
Hey Andrew,
Are there any remaining objections that are keeping you from picking
this patchset up?
thanks
-john
On Wed, 19 Mar 2008 10:29:34 -0700
"john stultz" <[email protected]> wrote:
> On Thu, Mar 6, 2008 at 5:08 AM, Rodolfo Giometti <[email protected]> wrote:
> > 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.
>
> Hey Andrew,
> Are there any remaining objections that are keeping you from picking
> this patchset up?
Not as far as I know. They're in my queue-to-review. Assistance there is
always useful ;)
On Wed, Mar 19, 2008 at 02:21:13PM -0700, Andrew Morton wrote:
> On Wed, 19 Mar 2008 10:29:34 -0700
> "john stultz" <[email protected]> wrote:
>
> > On Thu, Mar 6, 2008 at 5:08 AM, Rodolfo Giometti <[email protected]> wrote:
> > > 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.
> >
> > Hey Andrew,
> > Are there any remaining objections that are keeping you from picking
> > this patchset up?
>
> Not as far as I know. They're in my queue-to-review. Assistance there is
> always useful ;)
I looked it over a few times now, and didn't find anything objectionable.
But then, your standards are always somewhat higher than mine :)
Dave
--
http://www.codemonkey.org.uk
On Thu, 6 Mar 2008 13:09:04 +0100
Rodolfo Giometti <[email protected]> wrote:
> Adds support for the PPS sources connected with the CD (Carrier
> Detect) pin of a serial port.
>
> ...
>
> +#ifdef CONFIG_PPS_CLIENT_UART
> +
> +static int
> +uart_register_pps_port(struct uart_state *state, struct uart_port *port)
> +{
> + struct tty_driver *drv = port->info->tty->driver;
> + int ret;
> +
> + state->pps_info.owner = THIS_MODULE;
> + state->pps_info.dev = port->dev;
> + snprintf(state->pps_info.name, PPS_MAX_NAME_LEN, "%s%d",
> + drv->driver_name, port->line);
> + snprintf(state->pps_info.path, PPS_MAX_NAME_LEN, "/dev/%s%d",
> + drv->name, port->line);
umm, why are we hard-wiring "/dev" into the kernel source? Is it just for
user-friendly printks?
> + state->pps_info.mode = PPS_CAPTUREBOTH | \
> + PPS_OFFSETASSERT | PPS_OFFSETCLEAR | \
> + PPS_CANWAIT | PPS_TSFMT_TSPEC;
> +
> + ret = pps_register_source(&state->pps_info, PPS_CAPTUREBOTH | \
> + PPS_OFFSETASSERT | PPS_OFFSETCLEAR);
> + if (ret < 0) {
> + dev_err(port->dev, "cannot register PPS source \"%s\"\n",
> + state->pps_info.path);
> + return ret;
> + }
> + port->pps_source = ret;
> + dev_dbg(port->dev, "PPS source #%d \"%s\" added\n",
> + port->pps_source, state->pps_info.path);
> +
> + return 0;
> +}
> +
> +static void
> +uart_unregister_pps_port(struct uart_state *state, struct uart_port *port)
> +{
> + pps_unregister_source(port->pps_source);
> + dev_dbg(port->dev, "PPS source #%d \"%s\" removed\n",
> + port->pps_source, state->pps_info.path);
> +}
> +
> +#else
> +
> +#define uart_register_pps_port(state, port) do { } while (0)
> +#define uart_unregister_pps_port(state, port) do { } while (0)
Please never implement in cpp that which can be implemented in C. These
should have been static inlines. That's nicer, matches the
CONFIG_PPS_CLIENT_UART=y code and provides type checking.
> +#endif /* CONFIG_PPS_CLIENT_UART */
> +
> static int uart_set_info(struct uart_state *state,
> struct serial_struct __user *newinfo)
> {
> @@ -810,11 +859,19 @@ static int uart_set_info(struct uart_state *state,
> (port->flags & UPF_LOW_LATENCY) ? 1 : 0;
>
> check_and_exit:
> + /* PPS support enabled/disabled? */
> + if ((old_flags & UPF_HARDPPS_CD) != (new_flags & UPF_HARDPPS_CD)) {
> + if (new_flags & UPF_HARDPPS_CD)
> + uart_register_pps_port(state, port);
> + else
> + uart_unregister_pps_port(state, port);
> + }
> +
> retval = 0;
> if (port->type == PORT_UNKNOWN)
> goto exit;
> if (state->info->flags & UIF_INITIALIZED) {
> - if (((old_flags ^ port->flags) & UPF_SPD_MASK) ||
> + if (((old_flags ^ port->flags) & (UPF_SPD_MASK|UPF_HARDPPS_CD)) ||
> old_custom_divisor != port->custom_divisor) {
> /*
> * If they're setting up a custom divisor or speed,
> @@ -2148,6 +2205,12 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
> port->ops->config_port(port, flags);
> }
>
> + /*
> + * Add the PPS support for the current port.
> + */
> + if (port->flags & UPF_HARDPPS_CD)
> + uart_register_pps_port(state, port);
> +
> if (port->type != PORT_UNKNOWN) {
> unsigned long flags;
>
> @@ -2405,6 +2468,12 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *port)
> mutex_unlock(&state->mutex);
>
> /*
> + * Remove PPS support from the current port.
> + */
> + if (port->flags & UPF_HARDPPS_CD)
> + uart_unregister_pps_port(state, port);
> +
> + /*
> * Remove the devices from the tty layer
> */
> tty_unregister_device(drv->tty_driver, port->line);
On Thu, 6 Mar 2008 13:09:00 +0100
Rodolfo Giometti <[email protected]> wrote:
> +pps_core-y := pps.o kapi.o sysfs.o
Does it compile OK with CONFIG_SYSFS=n?
> +#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);
This name is insufficiently specific. Not only does it risk linkage
errors, it makes it ahrd for poeple to work out where the symbol came from.
I renamed it to pps_idr_lock.
> +DEFINE_IDR(pps_idr);
>
> ...
>
> +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);
The wait_event() stuff really shouldn't be here: it should be integral to
the refcounting:
void pps_dev_put(struct pps_device *pps)
{
spin_lock_irq(&pps_lock);
if (atomic_dec_and_test(&pps->usage))
idr_remove(&pps_idr, pps->id);
else
pps = NULL;
spin_unlock_irq(&pps_lock);
if (pps) {
/*
* Might need to do the below via schedule_work() if
* pps_dev_put() is to be callable from atomic context
*/
pps_sysfs_remove_source_entry(pps);
pps_unregister_cdev(pps);
kfree(pps);
}
}
As it stands, there might be deadlocks such as when a process which itself
holds a ref on the pps_device (with an open fd?) calls
pps_unregister_source.
Also, we need to take care that all processes which were waiting in
pps_unregister_source() get to finish their cleanup before we permit rmmod
to proceed. Is that handled somewhere?
> +void pps_event(int source, int event, void *data)
Please document the API in the kernel source. I realise there's a teeny
bit of documentation in pps.txt, but people don't think to look there and
it tends to go out of date.
It doesn't have to be fancy formal kerneldoc - it's better to add *good*
comments which tell people what they need to know. For some reason people
seem to add useless obvious stuff when they do their comments in kerneldoc
form.
> +{
> + 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);
The above pattern is repeated rather a lot and could perhaps be extracted
into a nice pps_dev_get() helper.
> + 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);
>
> ...
>
> +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);
That looks a bit odd. How can the pps_device not be registered in the IDR
tree at this stage?
> + if (!found)
> + return -ENODEV;
> +
> + file->private_data = pps;
> +
> + return 0;
> +}
>
> ...
>
> +/* 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... */
It's nice to avoid sprinkling #includes throughout the file, please.
People expect to be able to see what's being included in the first
screenful of the file.
> +/*
> + * 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;
> +};
> +
On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti <[email protected]> wrote:
> This patch adds the kernel side of the PPS support currently named
> "LinuxPPS".
> 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 @@
> +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);
Any specific reason you are creating the group by hand, and not assign
it to the default group in your class? It would will let the core
handle it for you. The device add uevent to userspace will happen
before you added the attributes, which is usually not nice.
Kay
On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti <[email protected]> wrote:
> This patch adds the kernel side of the PPS support currently named
> "LinuxPPS".
> 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 @@
> +/* 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;
Why is an entire class embedded into every device? :)
Kay
On Fri, Mar 21, 2008 at 04:36:44AM +0100, Kay Sievers wrote:
> On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti <[email protected]> wrote:
> > This patch adds the kernel side of the PPS support currently named
> > "LinuxPPS".
>
> > 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 @@
>
> > +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);
>
> Any specific reason you are creating the group by hand, and not assign
> it to the default group in your class? It would will let the core
> handle it for you. The device add uevent to userspace will happen
> before you added the attributes, which is usually not nice.
No any specific reason... I just supposed it was the-right-think(TM)!
:)
Can you please suggest me an URL where I can see how to rework the
code?
Ciao,
Rodolfo
--
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Linux Device Driver [email protected]
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On Fri, Mar 21, 2008 at 04:50:51AM +0100, Kay Sievers wrote:
> On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti <[email protected]> wrote:
> > This patch adds the kernel side of the PPS support currently named
> > "LinuxPPS".
>
> > 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 @@
>
> > +/* 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;
>
> Why is an entire class embedded into every device? :)
Uh! =:-o
Is that not right? What do you suggest to do?
Thanks,
Rodolfo
--
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Linux Device Driver [email protected]
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On Thu, Mar 20, 2008 at 01:04:00PM -0700, Andrew Morton wrote:
> On Thu, 6 Mar 2008 13:09:04 +0100
> Rodolfo Giometti <[email protected]> wrote:
>
> > Adds support for the PPS sources connected with the CD (Carrier
> > Detect) pin of a serial port.
> >
> > ...
> >
> > +#ifdef CONFIG_PPS_CLIENT_UART
> > +
> > +static int
> > +uart_register_pps_port(struct uart_state *state, struct uart_port *port)
> > +{
> > + struct tty_driver *drv = port->info->tty->driver;
> > + int ret;
> > +
> > + state->pps_info.owner = THIS_MODULE;
> > + state->pps_info.dev = port->dev;
> > + snprintf(state->pps_info.name, PPS_MAX_NAME_LEN, "%s%d",
> > + drv->driver_name, port->line);
> > + snprintf(state->pps_info.path, PPS_MAX_NAME_LEN, "/dev/%s%d",
> > + drv->name, port->line);
>
> umm, why are we hard-wiring "/dev" into the kernel source? Is it just for
> user-friendly printks?
Yes... :)
> > + state->pps_info.mode = PPS_CAPTUREBOTH | \
> > + PPS_OFFSETASSERT | PPS_OFFSETCLEAR | \
> > + PPS_CANWAIT | PPS_TSFMT_TSPEC;
> > +
> > + ret = pps_register_source(&state->pps_info, PPS_CAPTUREBOTH | \
> > + PPS_OFFSETASSERT | PPS_OFFSETCLEAR);
> > + if (ret < 0) {
> > + dev_err(port->dev, "cannot register PPS source \"%s\"\n",
> > + state->pps_info.path);
> > + return ret;
> > + }
> > + port->pps_source = ret;
> > + dev_dbg(port->dev, "PPS source #%d \"%s\" added\n",
> > + port->pps_source, state->pps_info.path);
> > +
> > + return 0;
> > +}
> > +
> > +static void
> > +uart_unregister_pps_port(struct uart_state *state, struct uart_port *port)
> > +{
> > + pps_unregister_source(port->pps_source);
> > + dev_dbg(port->dev, "PPS source #%d \"%s\" removed\n",
> > + port->pps_source, state->pps_info.path);
> > +}
> > +
> > +#else
> > +
> > +#define uart_register_pps_port(state, port) do { } while (0)
> > +#define uart_unregister_pps_port(state, port) do { } while (0)
>
> Please never implement in cpp that which can be implemented in C. These
> should have been static inlines. That's nicer, matches the
> CONFIG_PPS_CLIENT_UART=y code and provides type checking.
Are you saying that I should do:
static inline int
uart_register_pps_port(struct uart_state *state, struct uart_port *port)
{
/* Nop */
}
static inline void
uart_unregister_pps_port(struct uart_state *state, struct uart_port *port)
{
/* Nop */
}
?
Ciao,
Rodolfo
--
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Linux Device Driver [email protected]
Embedded Systems [email protected]
UNIX programming phone: +39 349 2432127
On Fri, 2008-03-21 at 11:56 +0100, Rodolfo Giometti wrote:
> On Fri, Mar 21, 2008 at 04:36:44AM +0100, Kay Sievers wrote:
> > On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti <[email protected]> wrote:
> > > This patch adds the kernel side of the PPS support currently named
> > > "LinuxPPS".
> >
> > > 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 @@
> >
> > > +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);
> >
> > Any specific reason you are creating the group by hand, and not assign
> > it to the default group in your class? It would will let the core
> > handle it for you. The device add uevent to userspace will happen
> > before you added the attributes, which is usually not nice.
>
> No any specific reason... I just supposed it was the-right-think(TM)!
> :)
>
> Can you please suggest me an URL where I can see how to rework the
> code?
You can assign class->dev_attrs the array of attributes, and the driver
core will create these attributes for all devices that get registered
with that class. See: drivers/base/core.c :: device_add_attrs().
Kay
On Fri, 2008-03-21 at 11:57 +0100, Rodolfo Giometti wrote:
> On Fri, Mar 21, 2008 at 04:50:51AM +0100, Kay Sievers wrote:
> > On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti <[email protected]> wrote:
> > > This patch adds the kernel side of the PPS support currently named
> > > "LinuxPPS".
> >
> > > 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 @@
> >
> > > +/* 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;
> >
> > Why is an entire class embedded into every device? :)
>
> Uh! =:-o
>
> Is that not right? What do you suggest to do?
It looks wrong. Do you use it for anything? I guess, you can just remove
it.
Kay
On Fri, 21 Mar 2008 12:17:36 +0100 Rodolfo Giometti <[email protected]> wrote:
> > > +#else
> > > +
> > > +#define uart_register_pps_port(state, port) do { } while (0)
> > > +#define uart_unregister_pps_port(state, port) do { } while (0)
> >
> > Please never implement in cpp that which can be implemented in C. These
> > should have been static inlines. That's nicer, matches the
> > CONFIG_PPS_CLIENT_UART=y code and provides type checking.
>
> Are you saying that I should do:
>
> static inline int
> uart_register_pps_port(struct uart_state *state, struct uart_port *port)
> {
> /* Nop */
> }
>
> static inline void
> uart_unregister_pps_port(struct uart_state *state, struct uart_port *port)
> {
> /* Nop */
> }
>
> ?
Yes please.
On Fri, Mar 21, 2008 at 10:41:25AM -0700, Andrew Morton wrote:
> On Fri, 21 Mar 2008 12:17:36 +0100 Rodolfo Giometti <[email protected]> wrote:
>
> > > > +#else
> > > > +
> > > > +#define uart_register_pps_port(state, port) do { } while (0)
> > > > +#define uart_unregister_pps_port(state, port) do { } while (0)
> > >
> > > Please never implement in cpp that which can be implemented in C. These
> > > should have been static inlines. That's nicer, matches the
> > > CONFIG_PPS_CLIENT_UART=y code and provides type checking.
> >
> > Are you saying that I should do:
> >
> > static inline int
> > uart_register_pps_port(struct uart_state *state, struct uart_port *port)
> > {
> > /* Nop */
> > }
> >
> > static inline void
> > uart_unregister_pps_port(struct uart_state *state, struct uart_port *port)
> > {
> > /* Nop */
> > }
> >
> > ?
>
> Yes please.
Fixed. I'll send a new patch ASAP.
Rodolfo
--
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On Fri, Mar 21, 2008 at 06:00:05PM +0100, Kay Sievers wrote:
> On Fri, 2008-03-21 at 11:56 +0100, Rodolfo Giometti wrote:
> > On Fri, Mar 21, 2008 at 04:36:44AM +0100, Kay Sievers wrote:
> > > On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti <[email protected]> wrote:
> > > > This patch adds the kernel side of the PPS support currently named
> > > > "LinuxPPS".
> > >
> > > > 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 @@
> > >
> > > > +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);
> > >
> > > Any specific reason you are creating the group by hand, and not assign
> > > it to the default group in your class? It would will let the core
> > > handle it for you. The device add uevent to userspace will happen
> > > before you added the attributes, which is usually not nice.
> >
> > No any specific reason... I just supposed it was the-right-think(TM)!
> > :)
> >
> > Can you please suggest me an URL where I can see how to rework the
> > code?
>
> You can assign class->dev_attrs the array of attributes, and the driver
> core will create these attributes for all devices that get registered
> with that class. See: drivers/base/core.c :: device_add_attrs().
Fixed, I'll provide a new patch ASAP.
Thanks,
Rodolfo
--
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Embedded Systems [email protected]
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On Fri, Mar 21, 2008 at 04:50:51AM +0100, Kay Sievers wrote:
> On Thu, Mar 6, 2008 at 1:09 PM, Rodolfo Giometti <[email protected]> wrote:
> > This patch adds the kernel side of the PPS support currently named
> > "LinuxPPS".
>
> > 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 @@
>
> > +/* 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;
>
> Why is an entire class embedded into every device? :)
Fixed, I'll provide a new patch ASAP.
Thanks,
Rodolfo
--
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Linux Device Driver [email protected]
Embedded Systems [email protected]
UNIX programming phone: +39 349 2432127
On Thu, Mar 20, 2008 at 01:03:56PM -0700, Andrew Morton wrote:
> On Thu, 6 Mar 2008 13:09:00 +0100
> Rodolfo Giometti <[email protected]> wrote:
>
> > +pps_core-y := pps.o kapi.o sysfs.o
>
> Does it compile OK with CONFIG_SYSFS=n?
Yes. Tested.
> > +#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);
>
> This name is insufficiently specific. Not only does it risk linkage
> errors, it makes it ahrd for poeple to work out where the symbol came from.
>
> I renamed it to pps_idr_lock.
Fixed.
> > +DEFINE_IDR(pps_idr);
> >
> > ...
> >
> > +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);
>
> The wait_event() stuff really shouldn't be here: it should be integral to
> the refcounting:
>
> void pps_dev_put(struct pps_device *pps)
> {
> spin_lock_irq(&pps_lock);
> if (atomic_dec_and_test(&pps->usage))
> idr_remove(&pps_idr, pps->id);
> else
> pps = NULL;
> spin_unlock_irq(&pps_lock);
> if (pps) {
> /*
> * Might need to do the below via schedule_work() if
> * pps_dev_put() is to be callable from atomic context
> */
> pps_sysfs_remove_source_entry(pps);
> pps_unregister_cdev(pps);
> kfree(pps);
> }
> }
I don't understand where I should use this function... :'(
>
> As it stands, there might be deadlocks such as when a process which itself
> holds a ref on the pps_device (with an open fd?) calls
> pps_unregister_source.
I can add a wait_event_interruptible in order to allow userland to
continue by receiving a signal. It could be acceptable?
> Also, we need to take care that all processes which were waiting in
> pps_unregister_source() get to finish their cleanup before we permit rmmod
> to proceed. Is that handled somewhere?
I don't understand the problem... this code as been added in order to
avoid the case where a pps_event() is called while a process executes
the pps_unregister_source(). If more processes try to execute this
code the first which enters will execute idr_remove() which prevents
another process to reach the wait_event()... is that wrong? =:-o
>
> > +void pps_event(int source, int event, void *data)
>
> Please document the API in the kernel source. I realise there's a teeny
> bit of documentation in pps.txt, but people don't think to look there and
> it tends to go out of date.
>
> It doesn't have to be fancy formal kerneldoc - it's better to add *good*
> comments which tell people what they need to know. For some reason people
> seem to add useless obvious stuff when they do their comments in kerneldoc
> form.
Here my proposal. It could be enought? :)
diff --git a/drivers/pps/kapi.c b/drivers/pps/kapi.c
index 6cac7b8..34b3b22 100644
--- a/drivers/pps/kapi.c
+++ b/drivers/pps/kapi.c
@@ -59,6 +59,18 @@ static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset)
* Exported functions
*/
+/* pps_register_source - add a PPS source in the system
+ *
+ * info: the PPS info struct
+ * default_params: the default PPS parameters of the new source
+ *
+ * This function is used to add a new PPS source in the system. The new
+ * source is described by info's fields and it will have, as default PPS
+ * parameters, the ones specified into default_params.
+ *
+ * The function returns, in case of success, the PPS source ID.
+ */
+
int pps_register_source(struct pps_source_info *info, int default_params)
{
struct pps_device *pps;
@@ -151,6 +163,14 @@ pps_register_source_exit:
}
EXPORT_SYMBOL(pps_register_source);
+/* pps_unregister_source - remove a PPS source from the system
+ *
+ * source: the PPS source ID
+ *
+ * This function is used to remove a previously registered PPS source from
+ * the system.
+ */
+
void pps_unregister_source(int source)
{
struct pps_device *pps;
@@ -177,6 +197,20 @@ void pps_unregister_source(int source)
}
EXPORT_SYMBOL(pps_unregister_source);
+/* pps_event - register a PPS event into the system
+ *
+ * source: the PPS source ID
+ * event: the event type
+ * data: userdef pointer
+ *
+ * This function is used by each PPS client in order to register a new
+ * PPS event into the system (it's usually called inside an IRQ handler).
+ *
+ * If an echo function is associated with the PPS source it will be called
+ * as:
+ * pps->info.echo(source, event, data);
+ */
+
void pps_event(int source, int event, void *data)
{
struct pps_device *pps;
> > +{
> > + struct 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);
>
> The above pattern is repeated rather a lot and could perhaps be extracted
> into a nice pps_dev_get() helper.
It could be... but, is it mandatory? ;)
> > + 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);
> >
> > ...
> >
> > +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);
>
> That looks a bit odd. How can the pps_device not be registered in the IDR
> tree at this stage?
This is needed in this scenario: a process just enters into
pps_unregister_source() while another one is executing pps_cdev_open()
on the same PPS source. We cannot open an unregistered source...
>
>
> > + if (!found)
> > + return -ENODEV;
> > +
> > + file->private_data = pps;
> > +
> > + return 0;
> > +}
> >
> > ...
> >
> > +/* 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... */
>
> It's nice to avoid sprinkling #includes throughout the file, please.
> People expect to be able to see what's being included in the first
> screenful of the file.
Fixed.
> > +/*
> > + * 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;
> > +};
> > +
>
I just fixed all your suggestions (apart what reported above) and I'm
ready to propose a new patch set.
Please let me know what else should I fix and if the proposed inline
documentation is ok.
Ciao,
Rodolfo
--
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Linux Device Driver [email protected]
Embedded Systems [email protected]
UNIX programming phone: +39 349 2432127
On Tue, 25 Mar 2008 15:44:00 +0100 Rodolfo Giometti <[email protected]> wrote:
> > > +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);
> >
> > The wait_event() stuff really shouldn't be here: it should be integral to
> > the refcounting:
> >
> > void pps_dev_put(struct pps_device *pps)
> > {
> > spin_lock_irq(&pps_lock);
> > if (atomic_dec_and_test(&pps->usage))
> > idr_remove(&pps_idr, pps->id);
> > else
> > pps = NULL;
> > spin_unlock_irq(&pps_lock);
> > if (pps) {
> > /*
> > * Might need to do the below via schedule_work() if
> > * pps_dev_put() is to be callable from atomic context
> > */
> > pps_sysfs_remove_source_entry(pps);
> > pps_unregister_cdev(pps);
> > kfree(pps);
> > }
> > }
>
> I don't understand where I should use this function... :'(
This is boilerplate standard linux kernel reference counting.
> >
> > As it stands, there might be deadlocks such as when a process which itself
> > holds a ref on the pps_device (with an open fd?) calls
> > pps_unregister_source.
>
> I can add a wait_event_interruptible in order to allow userland to
> continue by receiving a signal. It could be acceptable?
There should be no need to "wait" for anything. When the final reference
to an object is released, that object is cleaned up. Just like we do for
inodes, dentries, pages, files, and 100 other kernel objects.
The need to wait for something else to go away is a big red flag with
"busted refcounting" written on it.
> > Also, we need to take care that all processes which were waiting in
> > pps_unregister_source() get to finish their cleanup before we permit rmmod
> > to proceed. Is that handled somewhere?
>
> I don't understand the problem... this code as been added in order to
> avoid the case where a pps_event() is called while a process executes
> the pps_unregister_source(). If more processes try to execute this
> code the first which enters will execute idr_remove() which prevents
> another process to reach the wait_event()... is that wrong? =:-o
I was asking you!
We should get the reference counting and object lifetimes sorted out first.
There should be no "wait for <object> to be released" code. Once that is
in place, things like rmmod will also sort themselves out: it just won't be
possible to remove the module while there are live references to objects.
On Thu, 6 Mar 2008 13:09:00 +0100 Rodolfo Giometti <[email protected]> wrote:
> This patch adds the kernel side of the PPS support currently named
> "LinuxPPS".
powerpc:
drivers/pps/pps.c: In function 'pps_cdev_ioctl':
drivers/pps/pps.c:166: warning: format '%lld' expects type 'long long int', but argument 2 has type '__s64'
drivers/pps/kapi.c: In function 'pps_event':
drivers/pps/kapi.c:225: warning: format '%llu' expects type 'long long unsigned int', but argument 3 has type '__s64'
drivers/pps/sysfs.c: In function 'pps_show_assert':
drivers/pps/sysfs.c:42: warning: format '%lld' expects type 'long long int', but argument 3 has type '__s64'
drivers/pps/sysfs.c:42: warning: format '%lld' expects type 'long long int', but argument 3 has type '__s64'
drivers/pps/sysfs.c: In function 'pps_show_clear':
drivers/pps/sysfs.c:56: warning: format '%lld' expects type 'long long int', but argument 3 has type '__s64'
drivers/pps/sysfs.c:56: warning: format '%lld' expects type 'long long int', but argument 3 has type '__s64'