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authorChristopher S. Hall <christopher.s.hall@intel.com>2016-02-22 14:15:25 +0300
committerJohn Stultz <john.stultz@linaro.org>2016-03-04 01:23:43 +0300
commit719f1aa4a67199a3c4c68a03f94e5ec44d9d5f82 (patch)
tree0a6cdf499ae615abf88e8d826e0c63c431f54bdb
parentf9677e0f83080bb4186865868c359e72e1fac1ea (diff)
downloadlinux-719f1aa4a67199a3c4c68a03f94e5ec44d9d5f82.tar.xz
ptp: Add PTP_SYS_OFFSET_PRECISE for driver crosstimestamping
Currently, network /system cross-timestamping is performed in the PTP_SYS_OFFSET ioctl. The PTP clock driver reads gettimeofday() and the gettime64() callback provided by the driver. The cross-timestamp is best effort where the latency between the capture of system time (getnstimeofday()) and the device time (driver callback) may be significant. The getcrosststamp() callback and corresponding PTP_SYS_OFFSET_PRECISE ioctl allows the driver to perform this device/system correlation when for example cross timestamp hardware is available. Modern Intel systems can do this for onboard Ethernet controllers using the ART counter. There is virtually zero latency between captures of the ART and network device clock. The capabilities ioctl (PTP_CLOCK_GETCAPS), is augmented allowing applications to query whether or not drivers implement the getcrosststamp callback, providing more precise cross timestamping. Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: kevin.b.stanton@intel.com Cc: kevin.j.clarke@intel.com Cc: hpa@zytor.com Cc: jeffrey.t.kirsher@intel.com Cc: netdev@vger.kernel.org Acked-by: Richard Cochran <richardcochran@gmail.com> Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com> [jstultz: Commit subject tweaks] Signed-off-by: John Stultz <john.stultz@linaro.org>
-rw-r--r--Documentation/ptp/testptp.c6
-rw-r--r--drivers/ptp/ptp_chardev.c27
-rw-r--r--include/linux/ptp_clock_kernel.h8
-rw-r--r--include/uapi/linux/ptp_clock.h13
4 files changed, 51 insertions, 3 deletions
diff --git a/Documentation/ptp/testptp.c b/Documentation/ptp/testptp.c
index 6c6247aaa7b9..d99012f41602 100644
--- a/Documentation/ptp/testptp.c
+++ b/Documentation/ptp/testptp.c
@@ -277,13 +277,15 @@ int main(int argc, char *argv[])
" %d external time stamp channels\n"
" %d programmable periodic signals\n"
" %d pulse per second\n"
- " %d programmable pins\n",
+ " %d programmable pins\n"
+ " %d cross timestamping\n",
caps.max_adj,
caps.n_alarm,
caps.n_ext_ts,
caps.n_per_out,
caps.pps,
- caps.n_pins);
+ caps.n_pins,
+ caps.cross_timestamping);
}
}
diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index da7bae991552..579fd65299a0 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -22,6 +22,7 @@
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/timekeeping.h>
#include "ptp_private.h"
@@ -120,11 +121,13 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
struct ptp_clock_caps caps;
struct ptp_clock_request req;
struct ptp_sys_offset *sysoff = NULL;
+ struct ptp_sys_offset_precise precise_offset;
struct ptp_pin_desc pd;
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
struct ptp_clock_info *ops = ptp->info;
struct ptp_clock_time *pct;
struct timespec64 ts;
+ struct system_device_crosststamp xtstamp;
int enable, err = 0;
unsigned int i, pin_index;
@@ -138,6 +141,7 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
caps.n_per_out = ptp->info->n_per_out;
caps.pps = ptp->info->pps;
caps.n_pins = ptp->info->n_pins;
+ caps.cross_timestamping = ptp->info->getcrosststamp != NULL;
if (copy_to_user((void __user *)arg, &caps, sizeof(caps)))
err = -EFAULT;
break;
@@ -180,6 +184,29 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
err = ops->enable(ops, &req, enable);
break;
+ case PTP_SYS_OFFSET_PRECISE:
+ if (!ptp->info->getcrosststamp) {
+ err = -EOPNOTSUPP;
+ break;
+ }
+ err = ptp->info->getcrosststamp(ptp->info, &xtstamp);
+ if (err)
+ break;
+
+ ts = ktime_to_timespec64(xtstamp.device);
+ precise_offset.device.sec = ts.tv_sec;
+ precise_offset.device.nsec = ts.tv_nsec;
+ ts = ktime_to_timespec64(xtstamp.sys_realtime);
+ precise_offset.sys_realtime.sec = ts.tv_sec;
+ precise_offset.sys_realtime.nsec = ts.tv_nsec;
+ ts = ktime_to_timespec64(xtstamp.sys_monoraw);
+ precise_offset.sys_monoraw.sec = ts.tv_sec;
+ precise_offset.sys_monoraw.nsec = ts.tv_nsec;
+ if (copy_to_user((void __user *)arg, &precise_offset,
+ sizeof(precise_offset)))
+ err = -EFAULT;
+ break;
+
case PTP_SYS_OFFSET:
sysoff = kmalloc(sizeof(*sysoff), GFP_KERNEL);
if (!sysoff) {
diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index b8b73066d137..6b15e168148a 100644
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -38,6 +38,7 @@ struct ptp_clock_request {
};
};
+struct system_device_crosststamp;
/**
* struct ptp_clock_info - decribes a PTP hardware clock
*
@@ -67,6 +68,11 @@ struct ptp_clock_request {
* @gettime64: Reads the current time from the hardware clock.
* parameter ts: Holds the result.
*
+ * @getcrosststamp: Reads the current time from the hardware clock and
+ * system clock simultaneously.
+ * parameter cts: Contains timestamp (device,system) pair,
+ * where system time is realtime and monotonic.
+ *
* @settime64: Set the current time on the hardware clock.
* parameter ts: Time value to set.
*
@@ -105,6 +111,8 @@ struct ptp_clock_info {
int (*adjfreq)(struct ptp_clock_info *ptp, s32 delta);
int (*adjtime)(struct ptp_clock_info *ptp, s64 delta);
int (*gettime64)(struct ptp_clock_info *ptp, struct timespec64 *ts);
+ int (*getcrosststamp)(struct ptp_clock_info *ptp,
+ struct system_device_crosststamp *cts);
int (*settime64)(struct ptp_clock_info *p, const struct timespec64 *ts);
int (*enable)(struct ptp_clock_info *ptp,
struct ptp_clock_request *request, int on);
diff --git a/include/uapi/linux/ptp_clock.h b/include/uapi/linux/ptp_clock.h
index f0b7bfe5da92..ac6dded80ffa 100644
--- a/include/uapi/linux/ptp_clock.h
+++ b/include/uapi/linux/ptp_clock.h
@@ -51,7 +51,9 @@ struct ptp_clock_caps {
int n_per_out; /* Number of programmable periodic signals. */
int pps; /* Whether the clock supports a PPS callback. */
int n_pins; /* Number of input/output pins. */
- int rsv[14]; /* Reserved for future use. */
+ /* Whether the clock supports precise system-device cross timestamps */
+ int cross_timestamping;
+ int rsv[13]; /* Reserved for future use. */
};
struct ptp_extts_request {
@@ -81,6 +83,13 @@ struct ptp_sys_offset {
struct ptp_clock_time ts[2 * PTP_MAX_SAMPLES + 1];
};
+struct ptp_sys_offset_precise {
+ struct ptp_clock_time device;
+ struct ptp_clock_time sys_realtime;
+ struct ptp_clock_time sys_monoraw;
+ unsigned int rsv[4]; /* Reserved for future use. */
+};
+
enum ptp_pin_function {
PTP_PF_NONE,
PTP_PF_EXTTS,
@@ -124,6 +133,8 @@ struct ptp_pin_desc {
#define PTP_SYS_OFFSET _IOW(PTP_CLK_MAGIC, 5, struct ptp_sys_offset)
#define PTP_PIN_GETFUNC _IOWR(PTP_CLK_MAGIC, 6, struct ptp_pin_desc)
#define PTP_PIN_SETFUNC _IOW(PTP_CLK_MAGIC, 7, struct ptp_pin_desc)
+#define PTP_SYS_OFFSET_PRECISE \
+ _IOWR(PTP_CLK_MAGIC, 8, struct ptp_sys_offset_precise)
struct ptp_extts_event {
struct ptp_clock_time t; /* Time event occured. */