[PATCH 08/12] ptp: Added a brand new class driver for ptp clocks.

Grant Likely grant.likely at secretlab.ca
Wed Jun 16 03:00:10 EST 2010


On Tue, Jun 15, 2010 at 10:09 AM, Richard Cochran
<richardcochran at gmail.com> wrote:
> This patch adds an infrastructure for hardware clocks that implement
> IEEE 1588, the Precision Time Protocol (PTP). A class driver offers a
> registration method to particular hardware clock drivers. Each clock is
> exposed to user space as a character device with ioctls that allow tuning
> of the PTP clock.
>
> Signed-off-by: Richard Cochran <richard.cochran at omicron.at>
> ---
>  Documentation/ptp/ptp.txt        |   95 +++++++
>  Documentation/ptp/testptp.c      |  269 ++++++++++++++++++++
>  Documentation/ptp/testptp.mk     |   33 +++
>  drivers/Kconfig                  |    2 +
>  drivers/Makefile                 |    1 +
>  drivers/ptp/Kconfig              |   26 ++
>  drivers/ptp/Makefile             |    5 +
>  drivers/ptp/ptp_clock.c          |  514 ++++++++++++++++++++++++++++++++++++++
>  include/linux/Kbuild             |    1 +
>  include/linux/ptp_clock.h        |   79 ++++++
>  include/linux/ptp_clock_kernel.h |  137 ++++++++++
>  11 files changed, 1162 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/ptp/ptp.txt
>  create mode 100644 Documentation/ptp/testptp.c
>  create mode 100644 Documentation/ptp/testptp.mk
>  create mode 100644 drivers/ptp/Kconfig
>  create mode 100644 drivers/ptp/Makefile
>  create mode 100644 drivers/ptp/ptp_clock.c
>  create mode 100644 include/linux/ptp_clock.h
>  create mode 100644 include/linux/ptp_clock_kernel.h
>
> diff --git a/Documentation/ptp/ptp.txt b/Documentation/ptp/ptp.txt
> new file mode 100644
> index 0000000..46858b3
> --- /dev/null
> +++ b/Documentation/ptp/ptp.txt
> @@ -0,0 +1,95 @@
> +
> +* PTP infrastructure for Linux
> +
> +  This patch set introduces support for IEEE 1588 PTP clocks in
> +  Linux. Together with the SO_TIMESTAMPING socket options, this
> +  presents a standardized method for developing PTP user space
> +  programs, synchronizing Linux with external clocks, and using the
> +  ancillary features of PTP hardware clocks.
> +
> +  A new class driver exports a kernel interface for specific clock
> +  drivers and a user space interface. The infrastructure supports a
> +  complete set of PTP functionality.
> +
> +  + Basic clock operations
> +    - Set time
> +    - Get time
> +    - Shift the clock by a given offset atomically
> +    - Adjust clock frequency
> +
> +  + Ancillary clock features
> +    - One short or periodic alarms, with signal delivery to user program
> +    - Time stamp external events
> +    - Period output signals configurable from user space
> +    - Synchronization of the Linux system time via the PPS subsystem
> +
> +** PTP kernel API
> +
> +   A PTP clock driver registers itself with the class driver. The
> +   class driver handles all of the dealings with user space. The
> +   author of a clock driver need only implement the details of
> +   programming the clock hardware. The clock driver notifies the class
> +   driver of asynchronous events (alarms and external time stamps) via
> +   a simple message passing interface.
> +
> +   The class driver supports multiple PTP clock drivers. In normal use
> +   cases, only one PTP clock is needed. However, for testing and
> +   development, it can be useful to have more than one clock in a
> +   single system, in order to allow performance comparisons.
> +
> +** PTP user space API
> +
> +   The class driver creates a character device for each registered PTP
> +   clock. User space programs may control the clock using standardized
> +   ioctls. A program may query, enable, configure, and disable the
> +   ancillary clock features. User space can receive time stamped
> +   events via blocking read() and poll(). One shot and periodic
> +   signals may be configured via an ioctl API with semantics similar
> +   to the POSIX timer_settime() system call.
> +
> +   As an real life example, the following two patches for ptpd version
> +   1.0.0 demonstrate how the API works.
> +
> +   https://sourceforge.net/tracker/?func=detail&aid=2992845&group_id=139814&atid=744634
> +
> +   https://sourceforge.net/tracker/?func=detail&aid=2992847&group_id=139814&atid=744634

Question from an ignorant reviewer:  Why a new interface instead of
working with the existing high resolution timers infrastructure?

g.

> +
> +** Writing clock drivers
> +
> +   Clock drivers include include/linux/ptp_clock_kernel.h and register
> +   themselves by presenting a 'struct ptp_clock_info' to the
> +   registration method. Clock drivers must implement all of the
> +   functions in the interface. If a clock does not offer a particular
> +   ancillary feature, then the driver should just return -EOPNOTSUPP
> +   from those functions.
> +
> +   Drivers must ensure that all of the methods in interface are
> +   reentrant. Since most hardware implementations treat the time value
> +   as a 64 bit integer accessed as two 32 bit registers, drivers
> +   should use spin_lock_irqsave/spin_unlock_irqrestore to protect
> +   against concurrent access. This locking cannot be accomplished in
> +   class driver, since the lock may also be needed by the clock
> +   driver's interrupt service routine.
> +
> +** Supported hardware
> +
> +   + Standard Linux system timer
> +     - No special PTP features
> +     - For use with software time stamping
> +
> +   + Freescale eTSEC gianfar
> +     - 2 Time stamp external triggers, programmable polarity (opt. interrupt)
> +     - 2 Alarm registers (optional interrupt)
> +     - 3 Periodic signals (optional interrupt)
> +
> +   + National DP83640
> +     - 6 GPIOs programmable as inputs or outputs
> +     - 6 GPIOs with dedicated functions (LED/JTAG/clock) can also be
> +       used as general inputs or outputs
> +     - GPIO inputs can time stamp external triggers
> +     - GPIO outputs can produce periodic signals
> +     - 1 interrupt pin
> +
> +   + Intel IXP465
> +     - Auxiliary Slave/Master Mode Snapshot (optional interrupt)
> +     - Target Time (optional interrupt)
> diff --git a/Documentation/ptp/testptp.c b/Documentation/ptp/testptp.c
> new file mode 100644
> index 0000000..e30f758
> --- /dev/null
> +++ b/Documentation/ptp/testptp.c
> @@ -0,0 +1,269 @@
> +/*
> + * PTP 1588 clock support - User space test program
> + *
> + * Copyright (C) 2010 OMICRON electronics GmbH
> + *
> + *  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 <errno.h>
> +#include <fcntl.h>
> +#include <signal.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/ioctl.h>
> +#include <sys/mman.h>
> +#include <sys/stat.h>
> +#include <sys/time.h>
> +#include <sys/types.h>
> +#include <time.h>
> +#include <unistd.h>
> +
> +#include <linux/ptp_clock.h>
> +
> +static void handle_alarm(int s)
> +{
> +       printf("received signal %d\n", s);
> +}
> +
> +static int install_handler(int signum, void (*handler)(int))
> +{
> +       struct sigaction action;
> +       sigset_t mask;
> +
> +       /* Unblock the signal. */
> +       sigemptyset(&mask);
> +       sigaddset(&mask, signum);
> +       sigprocmask(SIG_UNBLOCK, &mask, NULL);
> +
> +       /* Install the signal handler. */
> +       action.sa_handler = handler;
> +       action.sa_flags = 0;
> +       sigemptyset(&action.sa_mask);
> +       sigaction(signum, &action, NULL);
> +
> +       return 0;
> +}
> +
> +static void usage(char *progname)
> +{
> +       fprintf(stderr,
> +               "usage: %s [options]\n"
> +               " -a val     request a one-shot alarm after 'val' seconds\n"
> +               " -A val     request a periodic alarm every 'val' seconds\n"
> +               " -c         query the ptp clock's capabilities\n"
> +               " -d name    device to open\n"
> +               " -e val     read 'val' external time stamp events\n"
> +               " -f val     adjust the ptp clock frequency by 'val' PPB\n"
> +               " -g         get the ptp clock time\n"
> +               " -h         prints this message\n"
> +               " -s         set the ptp clock time from the system time\n"
> +               " -t val     shift the ptp clock time by 'val' seconds\n"
> +               " -v         query the ptp clock api version\n",
> +               progname);
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +       struct ptp_clock_caps caps;
> +       struct ptp_clock_timer timer;
> +       struct ptp_extts_event event;
> +       struct ptp_clock_request request;
> +       struct timespec ts;
> +       char *progname;
> +       int c, cnt, fd, val = 0;
> +
> +       char *device = "/dev/ptp_clock_0";
> +       int adjfreq = 0x7fffffff;
> +       int adjtime = 0;
> +       int capabilities = 0;
> +       int extts = 0;
> +       int gettime = 0;
> +       int oneshot = 0;
> +       int periodic = 0;
> +       int settime = 0;
> +       int version = 0;
> +
> +       progname = strrchr(argv[0], '/');
> +       progname = progname ? 1+progname : argv[0];
> +       while (EOF != (c = getopt(argc, argv, "a:A:cd:e:f:ghst:v"))) {
> +               switch (c) {
> +               case 'a':
> +                       oneshot = atoi(optarg);
> +                       break;
> +               case 'A':
> +                       periodic = atoi(optarg);
> +                       break;
> +               case 'c':
> +                       capabilities = 1;
> +                       break;
> +               case 'd':
> +                       device = optarg;
> +                       break;
> +               case 'e':
> +                       extts = atoi(optarg);
> +                       break;
> +               case 'f':
> +                       adjfreq = atoi(optarg);
> +                       break;
> +               case 'g':
> +                       gettime = 1;
> +                       break;
> +               case 's':
> +                       settime = 1;
> +                       break;
> +               case 't':
> +                       adjtime = atoi(optarg);
> +                       break;
> +               case 'v':
> +                       version = 1;
> +                       break;
> +               case 'h':
> +                       usage(progname);
> +                       return 0;
> +               case '?':
> +               default:
> +                       usage(progname);
> +                       return -1;
> +               }
> +       }
> +
> +       fd = open(device, O_RDWR);
> +       if (fd < 0) {
> +               fprintf(stderr, "cannot open %s: %s", device, strerror(errno));
> +               return -1;
> +       }
> +
> +       if (version) {
> +               if (ioctl(fd, PTP_CLOCK_APIVERS, &val)) {
> +                       perror("PTP_CLOCK_APIVERS");
> +               } else {
> +                       printf("version = 0x%08x\n", val);
> +               }
> +       }
> +
> +       if (capabilities) {
> +               if (ioctl(fd, PTP_CLOCK_GETCAPS, &caps)) {
> +                       perror("PTP_CLOCK_GETCAPS");
> +               } else {
> +                       printf("capabilities:\n"
> +                              "  %d maximum frequency adjustment (PPB)\n"
> +                              "  %d programmable alarms\n"
> +                              "  %d external time stamp channels\n"
> +                              "  %d programmable periodic signals\n"
> +                              "  %d pulse per second\n",
> +                              caps.max_adj,
> +                              caps.n_alarm,
> +                              caps.n_ext_ts,
> +                              caps.n_per_out,
> +                              caps.pps);
> +               }
> +       }
> +
> +       if (0x7fffffff != adjfreq) {
> +               if (ioctl(fd, PTP_CLOCK_ADJFREQ, adjfreq)) {
> +                       perror("PTP_CLOCK_ADJFREQ");
> +               } else {
> +                       puts("frequency adjustment okay");
> +               }
> +       }
> +
> +       if (adjtime) {
> +               ts.tv_sec = adjtime;
> +               ts.tv_nsec = 0;
> +               if (ioctl(fd, PTP_CLOCK_ADJTIME, &ts)) {
> +                       perror("PTP_CLOCK_ADJTIME");
> +               } else {
> +                       puts("time shift okay");
> +               }
> +       }
> +
> +       if (gettime) {
> +               if (ioctl(fd, PTP_CLOCK_GETTIME, &ts)) {
> +                       perror("PTP_CLOCK_GETTIME");
> +               } else {
> +                       printf("clock time: %ld.%09ld or %s",
> +                              ts.tv_sec, ts.tv_nsec, ctime(&ts.tv_sec));
> +               }
> +       }
> +
> +       if (settime) {
> +               clock_gettime(CLOCK_REALTIME, &ts);
> +               if (ioctl(fd, PTP_CLOCK_SETTIME, &ts)) {
> +                       perror("PTP_CLOCK_SETTIME");
> +               } else {
> +                       puts("set time okay");
> +               }
> +       }
> +
> +       if (extts) {
> +               memset(&request, 0, sizeof(request));
> +               request.type = PTP_REQUEST_EXTTS;
> +               request.index = 0;
> +               request.flags = PTP_ENABLE_FEATURE;
> +               if (ioctl(fd, PTP_FEATURE_REQUEST, &request)) {
> +                       perror("PTP_FEATURE_REQUEST");
> +                       extts = 0;
> +               } else {
> +                       puts("set timer okay");
> +               }
> +               for (; extts; extts--) {
> +                       cnt = read(fd, &event, sizeof(event));
> +                       if (cnt != sizeof(event)) {
> +                               perror("read");
> +                               break;
> +                       }
> +                       printf("event index %d at %ld.%09ld\n", event.index,
> +                              event.ts.tv_sec, event.ts.tv_nsec);
> +               }
> +               /* Disable the feature again. */
> +               request.flags = 0;
> +               if (ioctl(fd, PTP_FEATURE_REQUEST, &request)) {
> +                       perror("PTP_FEATURE_REQUEST");
> +               }
> +       }
> +
> +       if (oneshot) {
> +               install_handler(SIGALRM, handle_alarm);
> +               memset(&timer, 0, sizeof(timer));
> +               timer.signum = SIGALRM;
> +               timer.tsp.it_value.tv_sec = oneshot;
> +               if (ioctl(fd, PTP_CLOCK_SETTIMER, &timer)) {
> +                       perror("PTP_CLOCK_SETTIMER");
> +               } else {
> +                       puts("set timer okay");
> +               }
> +               pause();
> +       }
> +
> +       if (periodic) {
> +               install_handler(SIGALRM, handle_alarm);
> +               memset(&timer, 0, sizeof(timer));
> +               timer.signum = SIGALRM;
> +               timer.tsp.it_value.tv_sec = periodic;
> +               timer.tsp.it_interval.tv_sec = periodic;
> +               if (ioctl(fd, PTP_CLOCK_SETTIMER, &timer)) {
> +                       perror("PTP_CLOCK_SETTIMER");
> +               } else {
> +                       puts("set timer okay");
> +               }
> +               while (1) {
> +                       pause();
> +               }
> +       }
> +
> +       close(fd);
> +       return 0;
> +}
> diff --git a/Documentation/ptp/testptp.mk b/Documentation/ptp/testptp.mk
> new file mode 100644
> index 0000000..4ef2d97
> --- /dev/null
> +++ b/Documentation/ptp/testptp.mk
> @@ -0,0 +1,33 @@
> +# PTP 1588 clock support - User space test program
> +#
> +# Copyright (C) 2010 OMICRON electronics GmbH
> +#
> +#  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.
> +
> +CC        = $(CROSS_COMPILE)gcc
> +INC       = -I$(KBUILD_OUTPUT)/usr/include
> +CFLAGS    = -Wall $(INC)
> +LDLIBS    = -lrt
> +PROGS     = testptp
> +
> +all: $(PROGS)
> +
> +testptp: testptp.o
> +
> +clean:
> +       rm -f testptp.o
> +
> +distclean: clean
> +       rm -f $(PROGS)
> diff --git a/drivers/Kconfig b/drivers/Kconfig
> index a2b902f..774fbd7 100644
> --- a/drivers/Kconfig
> +++ b/drivers/Kconfig
> @@ -52,6 +52,8 @@ source "drivers/spi/Kconfig"
>
>  source "drivers/pps/Kconfig"
>
> +source "drivers/ptp/Kconfig"
> +
>  source "drivers/gpio/Kconfig"
>
>  source "drivers/w1/Kconfig"
> diff --git a/drivers/Makefile b/drivers/Makefile
> index 91874e0..6d12b48 100644
> --- a/drivers/Makefile
> +++ b/drivers/Makefile
> @@ -76,6 +76,7 @@ obj-$(CONFIG_I2O)             += message/
>  obj-$(CONFIG_RTC_LIB)          += rtc/
>  obj-y                          += i2c/ media/
>  obj-$(CONFIG_PPS)              += pps/
> +obj-$(CONFIG_PTP_1588_CLOCK)   += ptp/
>  obj-$(CONFIG_W1)               += w1/
>  obj-$(CONFIG_POWER_SUPPLY)     += power/
>  obj-$(CONFIG_HWMON)            += hwmon/
> diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig
> new file mode 100644
> index 0000000..c80a25b
> --- /dev/null
> +++ b/drivers/ptp/Kconfig
> @@ -0,0 +1,26 @@
> +#
> +# PTP clock support configuration
> +#
> +
> +menu "PTP clock support"
> +
> +config PTP_1588_CLOCK
> +       tristate "PTP clock support"
> +       depends on EXPERIMENTAL
> +       help
> +         The IEEE 1588 standard defines a method to precisely
> +         synchronize distributed clocks over Ethernet networks. The
> +         standard defines a Precision Time Protocol (PTP), which can
> +         be used to achieve synchronization within a few dozen
> +         microseconds. In addition, with the help of special hardware
> +         time stamping units, it can be possible to achieve
> +         synchronization to within a few hundred nanoseconds.
> +
> +         This driver adds support for PTP clocks as character
> +         devices. If you want to use a PTP clock, then you should
> +         also enable at least one clock driver as well.
> +
> +         To compile this driver as a module, choose M here: the module
> +         will be called ptp_clock.
> +
> +endmenu
> diff --git a/drivers/ptp/Makefile b/drivers/ptp/Makefile
> new file mode 100644
> index 0000000..b86695c
> --- /dev/null
> +++ b/drivers/ptp/Makefile
> @@ -0,0 +1,5 @@
> +#
> +# Makefile for PTP 1588 clock support.
> +#
> +
> +obj-$(CONFIG_PTP_1588_CLOCK)           += ptp_clock.o
> diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
> new file mode 100644
> index 0000000..4753bf3
> --- /dev/null
> +++ b/drivers/ptp/ptp_clock.c
> @@ -0,0 +1,514 @@
> +/*
> + * PTP 1588 clock support
> + *
> + * Partially adapted from the Linux PPS driver.
> + *
> + * Copyright (C) 2010 OMICRON electronics GmbH
> + *
> + *  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/bitops.h>
> +#include <linux/cdev.h>
> +#include <linux/device.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/list.h>
> +#include <linux/module.h>
> +#include <linux/poll.h>
> +#include <linux/sched.h>
> +#include <linux/slab.h>
> +#include <linux/uaccess.h>
> +
> +#include <linux/ptp_clock_kernel.h>
> +#include <linux/ptp_clock.h>
> +
> +#define PTP_MAX_ALARMS 4
> +#define PTP_MAX_CLOCKS BITS_PER_LONG
> +#define PTP_MAX_TIMESTAMPS 128
> +
> +struct alarm {
> +       struct pid *pid;
> +       int sig;
> +};
> +
> +struct timestamp_event_queue {
> +       struct ptp_extts_event buf[PTP_MAX_TIMESTAMPS];
> +       int head;
> +       int tail;
> +       int overflow;
> +};
> +
> +struct ptp_clock {
> +       struct list_head list;
> +       struct cdev cdev;
> +       struct device *dev;
> +       struct ptp_clock_info *info;
> +       dev_t devid;
> +       int index; /* index into clocks.map, also the minor number */
> +
> +       struct alarm alarm[PTP_MAX_ALARMS];
> +       struct mutex alarm_mux; /* one process at a time setting an alarm */
> +
> +       struct timestamp_event_queue tsevq; /* simple fifo for time stamps */
> +       struct mutex tsevq_mux; /* one process at a time reading the fifo */
> +       wait_queue_head_t tsev_wq;
> +};
> +
> +/* private globals */
> +
> +static const struct file_operations ptp_fops;
> +static dev_t ptp_devt;
> +static struct class *ptp_class;
> +
> +static struct {
> +       struct list_head list;
> +       DECLARE_BITMAP(map, PTP_MAX_CLOCKS);
> +} clocks;
> +static DEFINE_SPINLOCK(clocks_lock); /* protects 'clocks' */
> +
> +/* time stamp event queue operations */
> +
> +static inline int queue_cnt(struct timestamp_event_queue *q)
> +{
> +       int cnt = q->tail - q->head;
> +       return cnt < 0 ? PTP_MAX_TIMESTAMPS + cnt : cnt;
> +}
> +
> +static inline int queue_free(struct timestamp_event_queue *q)
> +{
> +       return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
> +}
> +
> +static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
> +                                      struct ptp_clock_event *src)
> +{
> +       struct ptp_extts_event *dst;
> +       u32 remainder;
> +
> +       dst = &queue->buf[queue->tail];
> +
> +       dst->index = src->index;
> +       dst->ts.tv_sec = div_u64_rem(src->timestamp, 1000000000, &remainder);
> +       dst->ts.tv_nsec = remainder;
> +
> +       if (!queue_free(queue))
> +               queue->overflow++;
> +
> +       queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;
> +}
> +
> +/* public interface */
> +
> +struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info)
> +{
> +       struct ptp_clock *ptp;
> +       int err = 0, index, major = MAJOR(ptp_devt);
> +       unsigned long flags;
> +
> +       if (info->n_alarm > PTP_MAX_ALARMS)
> +               return ERR_PTR(-EINVAL);
> +
> +       /* Find a free clock slot and reserve it. */
> +       err = -EBUSY;
> +       spin_lock_irqsave(&clocks_lock, flags);
> +       index = find_first_zero_bit(clocks.map, PTP_MAX_CLOCKS);
> +       if (index < PTP_MAX_CLOCKS) {
> +               set_bit(index, clocks.map);
> +               spin_unlock_irqrestore(&clocks_lock, flags);
> +       } else {
> +               spin_unlock_irqrestore(&clocks_lock, flags);
> +               goto no_clock;
> +       }
> +
> +       /* Initialize a clock structure. */
> +       err = -ENOMEM;
> +       ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
> +       if (ptp == NULL)
> +               goto no_memory;
> +
> +       ptp->info = info;
> +       ptp->devid = MKDEV(major, index);
> +       ptp->index = index;
> +       mutex_init(&ptp->alarm_mux);
> +       mutex_init(&ptp->tsevq_mux);
> +       init_waitqueue_head(&ptp->tsev_wq);
> +
> +       /* Create a new device in our class. */
> +       ptp->dev = device_create(ptp_class, NULL, ptp->devid, ptp,
> +                                "ptp_clock_%d", ptp->index);
> +       if (IS_ERR(ptp->dev))
> +               goto no_device;
> +
> +       dev_set_drvdata(ptp->dev, ptp);
> +
> +       /* Register a character device. */
> +       cdev_init(&ptp->cdev, &ptp_fops);
> +       ptp->cdev.owner = info->owner;
> +       err = cdev_add(&ptp->cdev, ptp->devid, 1);
> +       if (err)
> +               goto no_cdev;
> +
> +       /* Clock is ready, add it into the list. */
> +       spin_lock_irqsave(&clocks_lock, flags);
> +       list_add(&ptp->list, &clocks.list);
> +       spin_unlock_irqrestore(&clocks_lock, flags);
> +
> +       return ptp;
> +
> +no_cdev:
> +       device_destroy(ptp_class, ptp->devid);
> +no_device:
> +       mutex_destroy(&ptp->alarm_mux);
> +       mutex_destroy(&ptp->tsevq_mux);
> +       kfree(ptp);
> +no_memory:
> +       spin_lock_irqsave(&clocks_lock, flags);
> +       clear_bit(index, clocks.map);
> +       spin_unlock_irqrestore(&clocks_lock, flags);
> +no_clock:
> +       return ERR_PTR(err);
> +}
> +EXPORT_SYMBOL(ptp_clock_register);
> +
> +int ptp_clock_unregister(struct ptp_clock *ptp)
> +{
> +       unsigned long flags;
> +
> +       /* Release the clock's resources. */
> +       cdev_del(&ptp->cdev);
> +       device_destroy(ptp_class, ptp->devid);
> +       mutex_destroy(&ptp->alarm_mux);
> +       mutex_destroy(&ptp->tsevq_mux);
> +
> +       /* Remove the clock from the list. */
> +       spin_lock_irqsave(&clocks_lock, flags);
> +       list_del(&ptp->list);
> +       clear_bit(ptp->index, clocks.map);
> +       spin_unlock_irqrestore(&clocks_lock, flags);
> +
> +       kfree(ptp);
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL(ptp_clock_unregister);
> +
> +void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
> +{
> +       switch (event->type) {
> +
> +       case PTP_CLOCK_ALARM:
> +               kill_pid(ptp->alarm[event->index].pid,
> +                        ptp->alarm[event->index].sig, 1);
> +               break;
> +
> +       case PTP_CLOCK_EXTTS:
> +               enqueue_external_timestamp(&ptp->tsevq, event);
> +               wake_up_interruptible(&ptp->tsev_wq);
> +               break;
> +
> +       case PTP_CLOCK_PPS:
> +               break;
> +       }
> +}
> +EXPORT_SYMBOL(ptp_clock_event);
> +
> +/* character device operations */
> +
> +static int ptp_ioctl(struct inode *node, struct file *fp,
> +                     unsigned int cmd, unsigned long arg)
> +{
> +       struct ptp_clock_caps caps;
> +       struct ptp_clock_request req;
> +       struct ptp_clock_timer timer;
> +       struct ptp_clock *ptp = fp->private_data;
> +       struct ptp_clock_info *ops = ptp->info;
> +       void *priv = ops->priv;
> +       struct timespec ts;
> +       int flags, index;
> +       int err = 0;
> +
> +       switch (cmd) {
> +
> +       case PTP_CLOCK_APIVERS:
> +               err = put_user(PTP_CLOCK_VERSION, (u32 __user *)arg);
> +               break;
> +
> +       case PTP_CLOCK_ADJFREQ:
> +               if (!capable(CAP_SYS_TIME))
> +                       return -EPERM;
> +               err = ops->adjfreq(priv, arg);
> +               break;
> +
> +       case PTP_CLOCK_ADJTIME:
> +               if (!capable(CAP_SYS_TIME))
> +                       return -EPERM;
> +               if (copy_from_user(&ts, (void __user *)arg, sizeof(ts)))
> +                       err = -EFAULT;
> +               else
> +                       err = ops->adjtime(priv, &ts);
> +               break;
> +
> +       case PTP_CLOCK_GETTIME:
> +               err = ops->gettime(priv, &ts);
> +               if (err)
> +                       break;
> +               err = copy_to_user((void __user *)arg, &ts, sizeof(ts));
> +               break;
> +
> +       case PTP_CLOCK_SETTIME:
> +               if (!capable(CAP_SYS_TIME))
> +                       return -EPERM;
> +               if (copy_from_user(&ts, (void __user *)arg, sizeof(ts)))
> +                       err = -EFAULT;
> +               else
> +                       err = ops->settime(priv, &ts);
> +               break;
> +
> +       case PTP_CLOCK_GETCAPS:
> +               memset(&caps, 0, sizeof(caps));
> +               caps.max_adj = ptp->info->max_adj;
> +               caps.n_alarm = ptp->info->n_alarm;
> +               caps.n_ext_ts = ptp->info->n_ext_ts;
> +               caps.n_per_out = ptp->info->n_per_out;
> +               caps.pps = ptp->info->pps;
> +               err = copy_to_user((void __user *)arg, &caps, sizeof(caps));
> +               break;
> +
> +       case PTP_CLOCK_GETTIMER:
> +               if (copy_from_user(&timer, (void __user *)arg, sizeof(timer))) {
> +                       err = -EFAULT;
> +                       break;
> +               }
> +               index = timer.alarm_index;
> +               if (index < 0 || index >= ptp->info->n_alarm) {
> +                       err = -EINVAL;
> +                       break;
> +               }
> +               err = ops->gettimer(priv, index, &timer.tsp);
> +               if (err)
> +                       break;
> +               err = copy_to_user((void __user *)arg, &timer, sizeof(timer));
> +               break;
> +
> +       case PTP_CLOCK_SETTIMER:
> +               if (copy_from_user(&timer, (void __user *)arg, sizeof(timer))) {
> +                       err = -EFAULT;
> +                       break;
> +               }
> +               index = timer.alarm_index;
> +               if (index < 0 || index >= ptp->info->n_alarm) {
> +                       err = -EINVAL;
> +                       break;
> +               }
> +               if (!valid_signal(timer.signum))
> +                       return -EINVAL;
> +               flags = timer.flags;
> +               if (flags & (flags != TIMER_ABSTIME)) {
> +                       err = -EINVAL;
> +                       break;
> +               }
> +               if (mutex_lock_interruptible(&ptp->alarm_mux))
> +                       return -ERESTARTSYS;
> +
> +               if (ptp->alarm[index].pid)
> +                       put_pid(ptp->alarm[index].pid);
> +
> +               ptp->alarm[index].pid = get_pid(task_pid(current));
> +               ptp->alarm[index].sig = timer.signum;
> +               err = ops->settimer(priv, index, flags, &timer.tsp);
> +
> +               mutex_unlock(&ptp->alarm_mux);
> +               break;
> +
> +       case PTP_FEATURE_REQUEST:
> +               if (copy_from_user(&req, (void __user *)arg, sizeof(req))) {
> +                       err = -EFAULT;
> +                       break;
> +               }
> +               switch (req.type) {
> +               case PTP_REQUEST_EXTTS:
> +               case PTP_REQUEST_PEROUT:
> +                       break;
> +               case PTP_REQUEST_PPS:
> +                       if (!capable(CAP_SYS_TIME))
> +                               return -EPERM;
> +                       break;
> +               default:
> +                       err = -EINVAL;
> +                       break;
> +               }
> +               if (err)
> +                       break;
> +               err = ops->enable(priv, &req,
> +                                 req.flags & PTP_ENABLE_FEATURE ? 1 : 0);
> +               break;
> +
> +       default:
> +               err = -ENOTTY;
> +               break;
> +       }
> +       return err;
> +}
> +
> +static int ptp_open(struct inode *inode, struct file *fp)
> +{
> +       struct ptp_clock *ptp;
> +       ptp = container_of(inode->i_cdev, struct ptp_clock, cdev);
> +
> +       fp->private_data = ptp;
> +
> +       return 0;
> +}
> +
> +static unsigned int ptp_poll(struct file *fp, poll_table *wait)
> +{
> +       struct ptp_clock *ptp = fp->private_data;
> +
> +       poll_wait(fp, &ptp->tsev_wq, wait);
> +
> +       return queue_cnt(&ptp->tsevq) ? POLLIN : 0;
> +}
> +
> +static ssize_t ptp_read(struct file *fp, char __user *buf,
> +                       size_t cnt, loff_t *off)
> +{
> +       struct ptp_clock *ptp = fp->private_data;
> +       struct timestamp_event_queue *queue = &ptp->tsevq;
> +       struct ptp_extts_event *event;
> +       size_t qcnt;
> +
> +       if (mutex_lock_interruptible(&ptp->tsevq_mux))
> +               return -ERESTARTSYS;
> +
> +       cnt = cnt / sizeof(struct ptp_extts_event);
> +
> +       if (wait_event_interruptible(ptp->tsev_wq,
> +                                    (qcnt = queue_cnt(&ptp->tsevq)))) {
> +               mutex_unlock(&ptp->tsevq_mux);
> +               return -ERESTARTSYS;
> +       }
> +
> +       if (cnt > qcnt)
> +               cnt = qcnt;
> +
> +       event = &queue->buf[queue->head];
> +
> +       if (copy_to_user(buf, event, cnt * sizeof(struct ptp_extts_event))) {
> +               mutex_unlock(&ptp->tsevq_mux);
> +               return -EFAULT;
> +       }
> +       queue->head = (queue->head + cnt) % PTP_MAX_TIMESTAMPS;
> +
> +       mutex_unlock(&ptp->tsevq_mux);
> +
> +       return cnt * sizeof(struct ptp_extts_event);
> +}
> +
> +static int ptp_release(struct inode *inode, struct file *fp)
> +{
> +       struct ptp_clock *ptp;
> +       struct itimerspec ts = {
> +               {0, 0}, {0, 0}
> +       };
> +       int i;
> +
> +       ptp = container_of(inode->i_cdev, struct ptp_clock, cdev);
> +
> +       for (i = 0; i < ptp->info->n_alarm; i++) {
> +               if (ptp->alarm[i].pid) {
> +                       ptp->info->settimer(ptp->info->priv, i, 0, &ts);
> +                       put_pid(ptp->alarm[i].pid);
> +                       ptp->alarm[i].pid = NULL;
> +               }
> +       }
> +       return 0;
> +}
> +
> +static const struct file_operations ptp_fops = {
> +       .owner          = THIS_MODULE,
> +       .ioctl          = ptp_ioctl,
> +       .open           = ptp_open,
> +       .poll           = ptp_poll,
> +       .read           = ptp_read,
> +       .release        = ptp_release,
> +};
> +
> +/* sysfs */
> +
> +static ssize_t ptp_show_status(struct device *dev,
> +                              struct device_attribute *attr, char *buf)
> +{
> +       struct ptp_clock *ptp = dev_get_drvdata(dev);
> +       return sprintf(buf,
> +                      "maximum adjustment:  %d\n"
> +                      "programmable alarms: %d\n"
> +                      "external timestamps: %d\n"
> +                      "periodic outputs:    %d\n"
> +                      "has pps:             %d\n"
> +                      "device index:        %d\n",
> +                      ptp->info->max_adj,
> +                      ptp->info->n_alarm,
> +                      ptp->info->n_ext_ts,
> +                      ptp->info->n_per_out,
> +                      ptp->info->pps,
> +                      ptp->index);
> +}
> +
> +struct device_attribute ptp_attrs[] = {
> +       __ATTR(capabilities, S_IRUGO, ptp_show_status, NULL),
> +       __ATTR_NULL,
> +};
> +
> +/* module operations */
> +
> +static void __exit ptp_exit(void)
> +{
> +       class_destroy(ptp_class);
> +       unregister_chrdev_region(ptp_devt, PTP_MAX_CLOCKS);
> +}
> +
> +static int __init ptp_init(void)
> +{
> +       int err;
> +
> +       INIT_LIST_HEAD(&clocks.list);
> +
> +       ptp_class = class_create(THIS_MODULE, "ptp");
> +       if (!ptp_class) {
> +               printk(KERN_ERR "ptp: failed to allocate class\n");
> +               return -ENOMEM;
> +       }
> +       ptp_class->dev_attrs = ptp_attrs;
> +
> +       err = alloc_chrdev_region(&ptp_devt, 0, PTP_MAX_CLOCKS, "ptp");
> +       if (err < 0) {
> +               printk(KERN_ERR "ptp: failed to allocate char device region\n");
> +               goto no_region;
> +       }
> +
> +       pr_info("PTP clock support registered\n");
> +       return 0;
> +
> +no_region:
> +       class_destroy(ptp_class);
> +       return err;
> +}
> +
> +subsys_initcall(ptp_init);
> +module_exit(ptp_exit);
> +
> +MODULE_AUTHOR("Richard Cochran <richard.cochran at omicron.at>");
> +MODULE_DESCRIPTION("PTP clocks support");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/Kbuild b/include/linux/Kbuild
> index 2fc8e14..9959fe4 100644
> --- a/include/linux/Kbuild
> +++ b/include/linux/Kbuild
> @@ -140,6 +140,7 @@ header-y += pkt_sched.h
>  header-y += posix_types.h
>  header-y += ppdev.h
>  header-y += prctl.h
> +header-y += ptp_clock.h
>  header-y += qnxtypes.h
>  header-y += qnx4_fs.h
>  header-y += radeonfb.h
> diff --git a/include/linux/ptp_clock.h b/include/linux/ptp_clock.h
> new file mode 100644
> index 0000000..5a509c5
> --- /dev/null
> +++ b/include/linux/ptp_clock.h
> @@ -0,0 +1,79 @@
> +/*
> + * PTP 1588 clock support - user space interface
> + *
> + * Copyright (C) 2010 OMICRON electronics GmbH
> + *
> + *  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 _PTP_CLOCK_H_
> +#define _PTP_CLOCK_H_
> +
> +#include <linux/ioctl.h>
> +#include <linux/types.h>
> +
> +#define PTP_ENABLE_FEATURE (1<<0)
> +#define PTP_RISING_EDGE    (1<<1)
> +#define PTP_FALLING_EDGE   (1<<2)
> +
> +enum ptp_request_types {
> +       PTP_REQUEST_EXTTS,
> +       PTP_REQUEST_PEROUT,
> +       PTP_REQUEST_PPS,
> +};
> +
> +struct ptp_clock_caps {
> +       __s32 max_adj; /* Maximum frequency adjustment, parts per billon. */
> +       int n_alarm;   /* Number of programmable alarms. */
> +       int n_ext_ts;  /* Number of external time stamp channels. */
> +       int n_per_out; /* Number of programmable periodic signals. */
> +       int pps;       /* Whether the clock supports a PPS callback. */
> +};
> +
> +struct ptp_clock_timer {
> +       int alarm_index;       /* Which alarm to query or configure. */
> +       int signum;            /* Requested signal. */
> +       int flags;             /* Zero or TIMER_ABSTIME, see TIMER_SETTIME(2) */
> +       struct itimerspec tsp; /* See TIMER_SETTIME(2) */
> +};
> +
> +struct ptp_clock_request {
> +       int type;  /* One of the ptp_request_types enumeration values. */
> +       int index; /* Which channel to configure. */
> +       struct timespec ts; /* For period signals, the desired period. */
> +       int flags; /* Bit field for PTP_ENABLE_FEATURE or other flags. */
> +};
> +
> +struct ptp_extts_event {
> +       int index;
> +       struct timespec ts;
> +};
> +
> +#define PTP_CLOCK_VERSION 0x00000001
> +
> +#define PTP_CLK_MAGIC '='
> +
> +#define PTP_CLOCK_APIVERS _IOR (PTP_CLK_MAGIC, 1, __u32)
> +#define PTP_CLOCK_ADJFREQ _IO  (PTP_CLK_MAGIC, 2)
> +#define PTP_CLOCK_ADJTIME _IOW (PTP_CLK_MAGIC, 3, struct timespec)
> +#define PTP_CLOCK_GETTIME _IOR (PTP_CLK_MAGIC, 4, struct timespec)
> +#define PTP_CLOCK_SETTIME _IOW (PTP_CLK_MAGIC, 5, struct timespec)
> +
> +#define PTP_CLOCK_GETCAPS   _IOR  (PTP_CLK_MAGIC, 6, struct ptp_clock_caps)
> +#define PTP_CLOCK_GETTIMER  _IOWR (PTP_CLK_MAGIC, 7, struct ptp_clock_timer)
> +#define PTP_CLOCK_SETTIMER  _IOW  (PTP_CLK_MAGIC, 8, struct ptp_clock_timer)
> +#define PTP_FEATURE_REQUEST _IOW  (PTP_CLK_MAGIC, 9, struct ptp_clock_request)
> +
> +#endif
> diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
> new file mode 100644
> index 0000000..d6cc158
> --- /dev/null
> +++ b/include/linux/ptp_clock_kernel.h
> @@ -0,0 +1,137 @@
> +/*
> + * PTP 1588 clock support
> + *
> + * Copyright (C) 2010 OMICRON electronics GmbH
> + *
> + *  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 _PTP_CLOCK_KERNEL_H_
> +#define _PTP_CLOCK_KERNEL_H_
> +
> +#include <linux/ptp_clock.h>
> +
> +/**
> + * struct ptp_clock_info - decribes a PTP hardware clock
> + *
> + * @owner:     The clock driver should set to THIS_MODULE.
> + * @name:      A short name to identify the clock.
> + * @max_adj:   The maximum possible frequency adjustment, in parts per billon.
> + * @n_alarm:   The number of programmable alarms.
> + * @n_ext_ts:  The number of external time stamp channels.
> + * @n_per_out: The number of programmable periodic signals.
> + * @pps:       Indicates whether the clock supports a PPS callback.
> + * @priv:      Passed to the clock operations, for the driver's private use.
> + *
> + * clock operations
> + *
> + * @adjfreq:  Adjusts the frequency of the hardware clock.
> + *            parameter delta: Desired period change in parts per billion.
> + *
> + * @adjtime:  Shifts the time of the hardware clock.
> + *            parameter ts: Desired change in seconds and nanoseconds.
> + *
> + * @gettime:  Reads the current time from the hardware clock.
> + *            parameter ts: Holds the result.
> + *
> + * @settime:  Set the current time on the hardware clock.
> + *            parameter ts: Time value to set.
> + *
> + * @gettimer: Reads the time remaining from the given timer.
> + *            parameter index: Which alarm to query.
> + *            parameter ts: Holds the result.
> + *
> + * @settimer: Arms the given timer for periodic or one shot operation.
> + *            parameter index: Which alarm to set.
> + *            parameter abs: TIMER_ABSTIME, or zero for relative timer.
> + *            parameter ts: Alarm time and period to set.
> + *
> + * @enable:   Request driver to enable or disable an ancillary feature.
> + *            parameter request: Desired resource to enable or disable.
> + *            parameter on: Caller passes one to enable or zero to disable.
> + *
> + * The callbacks must all return zero on success, non-zero otherwise.
> + */
> +
> +struct ptp_clock_info {
> +       struct module *owner;
> +       char name[16];
> +       s32 max_adj;
> +       int n_alarm;
> +       int n_ext_ts;
> +       int n_per_out;
> +       int pps;
> +       void *priv;
> +       int (*adjfreq)(void *priv, s32 delta);
> +       int (*adjtime)(void *priv, struct timespec *ts);
> +       int (*gettime)(void *priv, struct timespec *ts);
> +       int (*settime)(void *priv, struct timespec *ts);
> +       int (*gettimer)(void *priv, int index, struct itimerspec *ts);
> +       int (*settimer)(void *priv, int index, int abs, struct itimerspec *ts);
> +       int (*enable)(void *priv, struct ptp_clock_request *request, int on);
> +};
> +
> +struct ptp_clock;
> +
> +/**
> + * ptp_clock_register() - register a PTP hardware clock driver
> + *
> + * @info:  Structure describing the new clock.
> + */
> +
> +extern struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info);
> +
> +/**
> + * ptp_clock_unregister() - unregister a PTP hardware clock driver
> + *
> + * @ptp:  The clock to remove from service.
> + */
> +
> +extern int ptp_clock_unregister(struct ptp_clock *ptp);
> +
> +
> +enum ptp_clock_events {
> +       PTP_CLOCK_ALARM,
> +       PTP_CLOCK_EXTTS,
> +       PTP_CLOCK_PPS,
> +};
> +
> +/**
> + * struct ptp_clock_event - decribes a PTP hardware clock event
> + *
> + * @type:  One of the ptp_clock_events enumeration values.
> + * @index: Identifies the source of the event.
> + * @timestamp: When the event occured.
> + */
> +
> +struct ptp_clock_event {
> +       int type;
> +       int index;
> +       u64 timestamp;
> +};
> +
> +/**
> + * ptp_clock_event() - notify the PTP layer about an event
> + *
> + * This function should only be called from interrupt context.
> + *
> + * @ptp:    The clock obtained from ptp_clock_register().
> + * @event:  Message structure describing the event.
> + */
> +
> +extern void ptp_clock_event(struct ptp_clock *ptp,
> +                           struct ptp_clock_event *event);
> +
> +#endif
> --
> 1.6.3.3
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>



-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.


More information about the Linuxppc-dev mailing list