From 361800876f80da3915c46e388fc682532228b2c3 Mon Sep 17 00:00:00 2001 From: Miroslav Lichvar Date: Fri, 9 Nov 2018 11:14:44 +0100 Subject: ptp: add PTP_SYS_OFFSET_EXTENDED ioctl The PTP_SYS_OFFSET ioctl, which can be used to measure the offset between a PHC and the system clock, includes the total time that the driver needs to read the PHC timestamp. This typically involves reading of multiple PCI registers (sometimes in multiple iterations) and the register that contains the lowest bits of the timestamp is not read in the middle between the two readings of the system clock. This asymmetry causes the measured offset to have a significant error. Introduce a new ioctl, driver function, and helper functions, which allow the reading of the lowest register to be isolated from the other readings in order to reduce the asymmetry. The ioctl returns three timestamps for each measurement: - system time right before reading the lowest bits of the PHC timestamp - PHC time - system time immediately after reading the lowest bits of the PHC timestamp Cc: Richard Cochran Cc: Jacob Keller Cc: Marcelo Tosatti Signed-off-by: Miroslav Lichvar Signed-off-by: David S. Miller --- include/linux/ptp_clock_kernel.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'include/linux/ptp_clock_kernel.h') diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h index 51349d124ee5..a1ec0448e341 100644 --- a/include/linux/ptp_clock_kernel.h +++ b/include/linux/ptp_clock_kernel.h @@ -39,6 +39,15 @@ struct ptp_clock_request { }; struct system_device_crosststamp; + +/** + * struct ptp_system_timestamp - system time corresponding to a PHC timestamp + */ +struct ptp_system_timestamp { + struct timespec64 pre_ts; + struct timespec64 post_ts; +}; + /** * struct ptp_clock_info - decribes a PTP hardware clock * @@ -75,6 +84,14 @@ struct system_device_crosststamp; * @gettime64: Reads the current time from the hardware clock. * parameter ts: Holds the result. * + * @gettimex64: Reads the current time from the hardware clock and optionally + * also the system clock. + * parameter ts: Holds the PHC timestamp. + * parameter sts: If not NULL, it holds a pair of timestamps from + * the system clock. The first reading is made right before + * reading the lowest bits of the PHC timestamp and the second + * reading immediately follows that. + * * @getcrosststamp: Reads the current time from the hardware clock and * system clock simultaneously. * parameter cts: Contains timestamp (device,system) pair, @@ -124,6 +141,8 @@ 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 (*gettimex64)(struct ptp_clock_info *ptp, struct timespec64 *ts, + struct ptp_system_timestamp *sts); int (*getcrosststamp)(struct ptp_clock_info *ptp, struct system_device_crosststamp *cts); int (*settime64)(struct ptp_clock_info *p, const struct timespec64 *ts); @@ -247,4 +266,16 @@ static inline int ptp_schedule_worker(struct ptp_clock *ptp, #endif +static inline void ptp_read_system_prets(struct ptp_system_timestamp *sts) +{ + if (sts) + ktime_get_real_ts64(&sts->pre_ts); +} + +static inline void ptp_read_system_postts(struct ptp_system_timestamp *sts) +{ + if (sts) + ktime_get_real_ts64(&sts->post_ts); +} + #endif -- cgit v1.2.3-71-gd317 From 916444df305ef5b8a7d824aac7dd2aeba3a4db3b Mon Sep 17 00:00:00 2001 From: Miroslav Lichvar Date: Fri, 9 Nov 2018 11:14:45 +0100 Subject: ptp: deprecate gettime64() in favor of gettimex64() When a driver provides gettimex64(), use it in the PTP_SYS_OFFSET ioctl and POSIX clock's gettime() instead of gettime64(). Drivers should provide only one of the functions. Cc: Richard Cochran Cc: Jacob Keller Signed-off-by: Miroslav Lichvar Signed-off-by: David S. Miller --- drivers/ptp/ptp_chardev.c | 5 ++++- drivers/ptp/ptp_clock.c | 5 ++++- include/linux/ptp_clock_kernel.h | 2 ++ 3 files changed, 10 insertions(+), 2 deletions(-) (limited to 'include/linux/ptp_clock_kernel.h') diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c index aad0d36cf5c0..797fab33bb98 100644 --- a/drivers/ptp/ptp_chardev.c +++ b/drivers/ptp/ptp_chardev.c @@ -260,7 +260,10 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg) pct->sec = ts.tv_sec; pct->nsec = ts.tv_nsec; pct++; - err = ptp->info->gettime64(ptp->info, &ts); + if (ops->gettimex64) + err = ops->gettimex64(ops, &ts, NULL); + else + err = ops->gettime64(ops, &ts); if (err) goto out; pct->sec = ts.tv_sec; diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c index 5419a89d300e..40fda23e4b05 100644 --- a/drivers/ptp/ptp_clock.c +++ b/drivers/ptp/ptp_clock.c @@ -117,7 +117,10 @@ static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp) struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); int err; - err = ptp->info->gettime64(ptp->info, tp); + if (ptp->info->gettimex64) + err = ptp->info->gettimex64(ptp->info, tp, NULL); + else + err = ptp->info->gettime64(ptp->info, tp); return err; } diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h index a1ec0448e341..7121bbe76979 100644 --- a/include/linux/ptp_clock_kernel.h +++ b/include/linux/ptp_clock_kernel.h @@ -82,6 +82,8 @@ struct ptp_system_timestamp { * parameter delta: Desired change in nanoseconds. * * @gettime64: Reads the current time from the hardware clock. + * This method is deprecated. New drivers should implement + * the @gettimex64 method instead. * parameter ts: Holds the result. * * @gettimex64: Reads the current time from the hardware clock and optionally -- cgit v1.2.3-71-gd317