From d94ba80ebbea17f036cecb104398fbcd788aa742 Mon Sep 17 00:00:00 2001 From: Richard Cochran Date: Fri, 22 Apr 2011 12:03:08 +0200 Subject: ptp: Added a brand new class driver for ptp clocks. 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 presented as a standard POSIX clock. The ancillary clock features are exposed in two different ways, via the sysfs and by a character device. Signed-off-by: Richard Cochran Acked-by: Arnd Bergmann Acked-by: David S. Miller Signed-off-by: John Stultz --- Documentation/ptp/ptp.txt | 89 ++++++++++ Documentation/ptp/testptp.c | 381 +++++++++++++++++++++++++++++++++++++++++++ Documentation/ptp/testptp.mk | 33 ++++ 3 files changed, 503 insertions(+) create mode 100644 Documentation/ptp/ptp.txt create mode 100644 Documentation/ptp/testptp.c create mode 100644 Documentation/ptp/testptp.mk (limited to 'Documentation/ptp') diff --git a/Documentation/ptp/ptp.txt b/Documentation/ptp/ptp.txt new file mode 100644 index 000000000000..ae8fef86b832 --- /dev/null +++ b/Documentation/ptp/ptp.txt @@ -0,0 +1,89 @@ + +* PTP hardware clock 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 hardware clock 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 hardware clock 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 hardware clock user space API + + The class driver also creates a character device for each + registered clock. User space can use an open file descriptor from + the character device as a POSIX clock id and may call + clock_gettime, clock_settime, and clock_adjtime. These calls + implement the basic clock operations. + + 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 the POSIX timer_settime() system + call. + +** 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 + + + 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 000000000000..f59ded066108 --- /dev/null +++ b/Documentation/ptp/testptp.c @@ -0,0 +1,381 @@ +/* + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#define DEVICE "/dev/ptp0" + +#ifndef ADJ_SETOFFSET +#define ADJ_SETOFFSET 0x0100 +#endif + +#ifndef CLOCK_INVALID +#define CLOCK_INVALID -1 +#endif + +/* When glibc offers the syscall, this will go away. */ +#include +static int clock_adjtime(clockid_t id, struct timex *tx) +{ + return syscall(__NR_clock_adjtime, id, tx); +} + +static clockid_t get_clockid(int fd) +{ +#define CLOCKFD 3 +#define FD_TO_CLOCKID(fd) ((~(clockid_t) (fd) << 3) | CLOCKFD) + + return FD_TO_CLOCKID(fd); +} + +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 long ppb_to_scaled_ppm(int ppb) +{ + /* + * The 'freq' field in the 'struct timex' is in parts per + * million, but with a 16 bit binary fractional field. + * Instead of calculating either one of + * + * scaled_ppm = (ppb / 1000) << 16 [1] + * scaled_ppm = (ppb << 16) / 1000 [2] + * + * we simply use double precision math, in order to avoid the + * truncation in [1] and the possible overflow in [2]. + */ + return (long) (ppb * 65.536); +} + +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" + " -p val enable output with a period of 'val' nanoseconds\n" + " -P val enable or disable (val=1|0) the system clock PPS\n" + " -s set the ptp clock time from the system time\n" + " -S set the system time from the ptp clock time\n" + " -t val shift the ptp clock time by 'val' seconds\n", + progname); +} + +int main(int argc, char *argv[]) +{ + struct ptp_clock_caps caps; + struct ptp_extts_event event; + struct ptp_extts_request extts_request; + struct ptp_perout_request perout_request; + struct timespec ts; + struct timex tx; + + static timer_t timerid; + struct itimerspec timeout; + struct sigevent sigevent; + + char *progname; + int c, cnt, fd; + + char *device = DEVICE; + clockid_t clkid; + int adjfreq = 0x7fffffff; + int adjtime = 0; + int capabilities = 0; + int extts = 0; + int gettime = 0; + int oneshot = 0; + int periodic = 0; + int perout = -1; + int pps = -1; + int settime = 0; + + progname = strrchr(argv[0], '/'); + progname = progname ? 1+progname : argv[0]; + while (EOF != (c = getopt(argc, argv, "a:A:cd:e:f:ghp:P:sSt: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 'p': + perout = atoi(optarg); + break; + case 'P': + pps = atoi(optarg); + break; + case 's': + settime = 1; + break; + case 'S': + settime = 2; + break; + case 't': + adjtime = atoi(optarg); + break; + case 'h': + usage(progname); + return 0; + case '?': + default: + usage(progname); + return -1; + } + } + + fd = open(device, O_RDWR); + if (fd < 0) { + fprintf(stderr, "opening %s: %s\n", device, strerror(errno)); + return -1; + } + + clkid = get_clockid(fd); + if (CLOCK_INVALID == clkid) { + fprintf(stderr, "failed to read clock id\n"); + return -1; + } + + 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) { + memset(&tx, 0, sizeof(tx)); + tx.modes = ADJ_FREQUENCY; + tx.freq = ppb_to_scaled_ppm(adjfreq); + if (clock_adjtime(clkid, &tx)) { + perror("clock_adjtime"); + } else { + puts("frequency adjustment okay"); + } + } + + if (adjtime) { + memset(&tx, 0, sizeof(tx)); + tx.modes = ADJ_SETOFFSET; + tx.time.tv_sec = adjtime; + tx.time.tv_usec = 0; + if (clock_adjtime(clkid, &tx) < 0) { + perror("clock_adjtime"); + } else { + puts("time shift okay"); + } + } + + if (gettime) { + if (clock_gettime(clkid, &ts)) { + perror("clock_gettime"); + } else { + printf("clock time: %ld.%09ld or %s", + ts.tv_sec, ts.tv_nsec, ctime(&ts.tv_sec)); + } + } + + if (settime == 1) { + clock_gettime(CLOCK_REALTIME, &ts); + if (clock_settime(clkid, &ts)) { + perror("clock_settime"); + } else { + puts("set time okay"); + } + } + + if (settime == 2) { + clock_gettime(clkid, &ts); + if (clock_settime(CLOCK_REALTIME, &ts)) { + perror("clock_settime"); + } else { + puts("set time okay"); + } + } + + if (extts) { + memset(&extts_request, 0, sizeof(extts_request)); + extts_request.index = 0; + extts_request.flags = PTP_ENABLE_FEATURE; + if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) { + perror("PTP_EXTTS_REQUEST"); + extts = 0; + } else { + puts("external time stamp request okay"); + } + for (; extts; extts--) { + cnt = read(fd, &event, sizeof(event)); + if (cnt != sizeof(event)) { + perror("read"); + break; + } + printf("event index %u at %lld.%09u\n", event.index, + event.t.sec, event.t.nsec); + fflush(stdout); + } + /* Disable the feature again. */ + extts_request.flags = 0; + if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) { + perror("PTP_EXTTS_REQUEST"); + } + } + + if (oneshot) { + install_handler(SIGALRM, handle_alarm); + /* Create a timer. */ + sigevent.sigev_notify = SIGEV_SIGNAL; + sigevent.sigev_signo = SIGALRM; + if (timer_create(clkid, &sigevent, &timerid)) { + perror("timer_create"); + return -1; + } + /* Start the timer. */ + memset(&timeout, 0, sizeof(timeout)); + timeout.it_value.tv_sec = oneshot; + if (timer_settime(timerid, 0, &timeout, NULL)) { + perror("timer_settime"); + return -1; + } + pause(); + timer_delete(timerid); + } + + if (periodic) { + install_handler(SIGALRM, handle_alarm); + /* Create a timer. */ + sigevent.sigev_notify = SIGEV_SIGNAL; + sigevent.sigev_signo = SIGALRM; + if (timer_create(clkid, &sigevent, &timerid)) { + perror("timer_create"); + return -1; + } + /* Start the timer. */ + memset(&timeout, 0, sizeof(timeout)); + timeout.it_interval.tv_sec = periodic; + timeout.it_value.tv_sec = periodic; + if (timer_settime(timerid, 0, &timeout, NULL)) { + perror("timer_settime"); + return -1; + } + while (1) { + pause(); + } + timer_delete(timerid); + } + + if (perout >= 0) { + if (clock_gettime(clkid, &ts)) { + perror("clock_gettime"); + return -1; + } + memset(&perout_request, 0, sizeof(perout_request)); + perout_request.index = 0; + perout_request.start.sec = ts.tv_sec + 2; + perout_request.start.nsec = 0; + perout_request.period.sec = 0; + perout_request.period.nsec = perout; + if (ioctl(fd, PTP_PEROUT_REQUEST, &perout_request)) { + perror("PTP_PEROUT_REQUEST"); + } else { + puts("periodic output request okay"); + } + } + + if (pps != -1) { + int enable = pps ? 1 : 0; + if (ioctl(fd, PTP_ENABLE_PPS, enable)) { + perror("PTP_ENABLE_PPS"); + } else { + puts("pps for system time request okay"); + } + } + + close(fd); + return 0; +} diff --git a/Documentation/ptp/testptp.mk b/Documentation/ptp/testptp.mk new file mode 100644 index 000000000000..4ef2d9755421 --- /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) -- cgit