Introduce: - ops for getting and setting the HW timestamp latch point, - enumerate possible HW timestamp latch point, - new sysfs ptp device attribute as user knob.
HW support of PTP/timesync solutions in network PHY chips can be achieved with two different approaches, the timestamp maybe latched either in the beginning or after the Start of Frame Delimiter (SFD) [1]. Allow ptp device drivers to provide user with control over the timestamp latch point. [1] https://www.ieee802.org/3/cx/public/april20/tse_3cx_01_0420.pdf Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalew...@intel.com> --- drivers/ptp/ptp_sysfs.c | 44 ++++++++++++++++++++++++++++++++ include/linux/ptp_clock_kernel.h | 26 +++++++++++++++++++ 2 files changed, 70 insertions(+) diff --git a/drivers/ptp/ptp_sysfs.c b/drivers/ptp/ptp_sysfs.c index 6b1b8f57cd95..7e9f6ef368b6 100644 --- a/drivers/ptp/ptp_sysfs.c +++ b/drivers/ptp/ptp_sysfs.c @@ -28,6 +28,46 @@ static ssize_t max_phase_adjustment_show(struct device *dev, } static DEVICE_ATTR_RO(max_phase_adjustment); +static ssize_t ts_point_show(struct device *dev, struct device_attribute *attr, + char *page) +{ + struct ptp_clock *ptp = dev_get_drvdata(dev); + enum ptp_ts_point point; + int err; + + if (!ptp->info->get_ts_point) + return -EOPNOTSUPP; + err = ptp->info->get_ts_point(ptp->info, &point); + if (err) + return err; + + return sysfs_emit(page, "%d\n", point); +} + +static ssize_t ts_point_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct ptp_clock *ptp = dev_get_drvdata(dev); + enum ptp_ts_point point; + int err; + u8 val; + + if (!ptp->info->set_ts_point) + return -EOPNOTSUPP; + if (kstrtou8(buf, 0, &val)) + return -EINVAL; + if (val > PTP_TS_POINT_MAX) + return -EINVAL; + point = val; + + err = ptp->info->set_ts_point(ptp->info, point); + if (err) + return err; + + return count; +} +static DEVICE_ATTR_RW(ts_point); + #define PTP_SHOW_INT(name, var) \ static ssize_t var##_show(struct device *dev, \ struct device_attribute *attr, char *page) \ @@ -335,6 +375,7 @@ static struct attribute *ptp_attrs[] = { &dev_attr_pps_enable.attr, &dev_attr_n_vclocks.attr, &dev_attr_max_vclocks.attr, + &dev_attr_ts_point.attr, NULL }; @@ -363,6 +404,9 @@ static umode_t ptp_is_attribute_visible(struct kobject *kobj, } else if (attr == &dev_attr_max_phase_adjustment.attr) { if (!info->adjphase || !info->getmaxphase) mode = 0; + } else if (attr == &dev_attr_ts_point.attr) { + if (!info->get_ts_point && !info->set_ts_point) + mode = 0; } return mode; diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h index c892d22ce0a7..ee4b625bca2c 100644 --- a/include/linux/ptp_clock_kernel.h +++ b/include/linux/ptp_clock_kernel.h @@ -55,6 +55,20 @@ struct ptp_system_timestamp { clockid_t clockid; }; +/** + * enum ptp_ts_point - possible timestamp latch points (IEEE 802.3cx) + * PTP_TS_POINT_SFD: timestamp latched at the beginning of sending Start + * of Frame Delimiter (SFD) + * PTP_TS_POINT_POST_SFD: timestamp latched at the end of sending Start + * of Frame Delimiter (SFD) + */ +enum ptp_ts_point { + PTP_TS_POINT_SFD, + PTP_TS_POINT_POST_SFD, + __PTP_TS_POINT_MAX +}; +#define PTP_TS_POINT_MAX (__PTP_TS_POINT_MAX - 1) + /** * struct ptp_clock_info - describes a PTP hardware clock * @@ -159,6 +173,14 @@ struct ptp_system_timestamp { * scheduling time (>=0) or negative value in case further * scheduling is not required. * + * @set_ts_point: Request change of timestamp latch point, as the timestamp + * could be latched at the beginning or at the end of start + * frame delimiter (SFD), as described in IEEE 802.3cx + * specification. + * + * @get_ts_point: Obtain the timestamp measurement latch point, counterpart of + * .set_ts_point() for getting currently configured value. + * * Drivers should embed their ptp_clock_info within a private * structure, obtaining a reference to it using container_of(). * @@ -195,6 +217,10 @@ struct ptp_clock_info { int (*verify)(struct ptp_clock_info *ptp, unsigned int pin, enum ptp_pin_function func, unsigned int chan); long (*do_aux_work)(struct ptp_clock_info *ptp); + int (*set_ts_point)(struct ptp_clock_info *ptp, + enum ptp_ts_point point); + int (*get_ts_point)(struct ptp_clock_info *ptp, + enum ptp_ts_point *point); }; struct ptp_clock; -- 2.38.1
