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Message-ID: <AANLkTin4lYghEWhjzEyARvYDgHaXdniwLbfyZ4jY0rwm@mail.gmail.com>
Date: Tue, 15 Jun 2010 11:00:10 -0600
From: Grant Likely <grant.likely@...retlab.ca>
To: Richard Cochran <richardcochran@...il.com>
Cc: netdev@...r.kernel.org, devicetree-discuss@...ts.ozlabs.org,
linuxppc-dev@...ts.ozlabs.org,
linux-arm-kernel@...ts.infradead.org,
Krzysztof Halasa <khc@...waw.pl>,
Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 08/12] ptp: Added a brand new class driver for ptp clocks.
On Tue, Jun 15, 2010 at 10:09 AM, Richard Cochran
<richardcochran@...il.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@...cron.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@...cron.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@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
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