ptp: introduce PTP_CLOCK_EXTOFF event for the measured external offset

This change is for the PHC devices that can measure the phase offset
between PHC signal and the external signal, such as the 1PPS signal of
GNSS. Reporting PTP_CLOCK_EXTOFF to user space will be piggy-backed to
the existing ptp_extts_event so that application such as ts2phc can
poll the external offset the same way as extts. Hence, ts2phc can use
the offset to achieve the alignment between PHC and the external signal
by the help of either SW or HW filters.

Signed-off-by: Min Li <min.li.xe@renesas.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: Add .getmaxphase callback to ptp_clock_info

Enables advertisement of the maximum offset supported by the phase control
functionality of PHCs. The callback is used to return an error if an offset
not supported by the PHC is used in ADJ_OFFSET. The ioctls
PTP_CLOCK_GETCAPS and PTP_CLOCK_GETCAPS2 now advertise the maximum offset a
PHC's phase control functionality is capable of supporting. Introduce new
sysfs node, max_phase_adjustment.

Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Maciek Machnikowski <maciek@machnikowski.net>
Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: Clarify ptp_clock_info .adjphase expects an internal servo to be used

.adjphase expects a PHC to use an internal servo algorithm to correct the
provided phase offset target in the callback. Implementation of the
internal servo algorithm are defined by the individual devices.

Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: remove the .adjfreq interface function

Now that all drivers have been converted to .adjfine, we can remove the
.adjfreq from the interface structure.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: introduce helpers to adjust by scaled parts per million

Many drivers implement the .adjfreq or .adjfine PTP op function with the
same basic logic:

1. Determine a base frequency value
2. Multiply this by the abs() of the requested adjustment, then divide by
the appropriate divisor (1 billion, or 65,536 billion).
3. Add or subtract this difference from the base frequency to calculate a
new adjustment.

A few drivers need the difference and direction rather than the combined
new increment value.

I recently converted the Intel drivers to .adjfine and the scaled parts per
million (65.536 parts per billion) logic. To avoid overflow with minimal
loss of precision, mul_u64_u64_div_u64 was used.

The basic logic used by all of these drivers is very similar, and leads to
a lot of duplicate code to perform the same task.

Rather than keep this duplicate code, introduce diff_by_scaled_ppm and
adjust_by_scaled_ppm. These helper functions calculate the difference or
adjustment necessary based on the scaled parts per million input.

The diff_by_scaled_ppm function returns true if the difference should be
subtracted, and false otherwise.

Update the Intel drivers to use the new helper functions. Other vendor
drivers will be converted to .adjfine and this helper function in the
following changes.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: add missing documentation for parameters

The ptp_find_pin_unlocked function and the ptp_system_timestamp structure
didn't document their parameters and fields. Fix this.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: Pass hwtstamp to ptp_convert_timestamp()

ptp_convert_timestamp() converts only the timestamp hwtstamp, which is
a field of the argument with the type struct skb_shared_hwtstamps *. So
a pointer to the hwtstamp field of this structure is sufficient.

Rework ptp_convert_timestamp() to use an argument of type ktime_t *.
This allows to add additional timestamp manipulation stages before the
call of ptp_convert_timestamp().

Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

ptp: Add cycles support for virtual clocks

ptp vclocks require a free running time for their timecounter.
Currently only a physical clock forced to free running is supported.
If vclocks are used, then the physical clock cannot be synchronized
anymore. The synchronized time is not available in hardware in this
case. As a result, timed transmission with TAPRIO hardware support
is not possible anymore.

If hardware would support a free running time additionally to the
physical clock, then the physical clock does not need to be forced to
free running. Thus, the physical clocks can still be synchronized
while vclocks are in use.

The physical clock could be used to synchronize the time domain of the
TSN network and trigger TAPRIO. In parallel vclocks can be used to
synchronize other time domains.

Introduce support for a free running cycle counter called cycles to
physical clocks. Rework ptp vclocks to use this free running cycle
counter. Default implementation is based on time of physical clock.
Thus, behavior of ptp vclocks based on physical clocks without free
running cycle counter is identical to previous behavior.

Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net: lan966x: Fix compilation error

Starting from the blamed commit, the lan966x build fails with the
following compilation error:

drivers/net/ethernet/microchip/lan966x/lan966x_ptp.c:342:9: error: implicit declaration of function ‘ptp_find_pin_unlocked’ [-Werror=implicit-function-declaration]
342 | pin = ptp_find_pin_unlocked(phc->clock, PTP_PF_EXTTS, 0);

The issue is that there is no stub function for ptp_find_pin_unlocked
in case CONFIG_PTP_1588_CLOCK is not selected. Therefore add one.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: f3d8e0a9c28ba0 ("net: lan966x: Add support for PTP_PF_EXTTS")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: fix SOF_TIMESTAMPING_BIND_PHC to work with multiple sockets

When multiple sockets using the SOF_TIMESTAMPING_BIND_PHC flag received
a packet with a hardware timestamp (e.g. multiple PTP instances in
different PTP domains using the UDPv4/v6 multicast or L2 transport),
the timestamps received on some sockets were corrupted due to repeated
conversion of the same timestamp (by the same or different vclocks).

Fix ptp_convert_timestamp() to not modify the shared skb timestamp
and return the converted timestamp as a ktime_t instead. If the
conversion fails, return 0 to not confuse the application with
timestamps corresponding to an unexpected PHC.

Fixes: d7c088265588 ("net: socket: support hardware timestamp conversion to PHC bound")
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Yangbo Lu <yangbo.lu@nxp.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ethernet: fix PTP_1588_CLOCK dependencies

The 'imply' keyword does not do what most people think it does, it only
politely asks Kconfig to turn on another symbol, but does not prevent
it from being disabled manually or built as a loadable module when the
user is built-in. In the ICE driver, the latter now causes a link failure:

aarch64-linux-ld: drivers/net/ethernet/intel/ice/ice_main.o: in function `ice_eth_ioctl':
ice_main.c:(.text+0x13b0): undefined reference to `ice_ptp_get_ts_config'
ice_main.c:(.text+0x13b0): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `ice_ptp_get_ts_config'
aarch64-linux-ld: ice_main.c:(.text+0x13bc): undefined reference to `ice_ptp_set_ts_config'
ice_main.c:(.text+0x13bc): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `ice_ptp_set_ts_config'
aarch64-linux-ld: drivers/net/ethernet/intel/ice/ice_main.o: in function `ice_prepare_for_reset':
ice_main.c:(.text+0x31fc): undefined reference to `ice_ptp_release'
ice_main.c:(.text+0x31fc): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `ice_ptp_release'
aarch64-linux-ld: drivers/net/ethernet/intel/ice/ice_main.o: in function `ice_rebuild':

This is a recurring problem in many drivers, and we have discussed
it several times befores, without reaching a consensus. I'm providing
a link to the previous email thread for reference, which discusses
some related problems.

To solve the dependency issue better than the 'imply' keyword, introduce a
separate Kconfig symbol "CONFIG_PTP_1588_CLOCK_OPTIONAL" that any driver
can depend on if it is able to use PTP support when available, but works
fine without it. Whenever CONFIG_PTP_1588_CLOCK=m, those drivers are
then prevented from being built-in, the same way as with a 'depends on
PTP_1588_CLOCK || !PTP_1588_CLOCK' dependency that does the same trick,
but that can be rather confusing when you first see it.

Since this should cover the dependencies correctly, the IS_REACHABLE()
hack in the header is no longer needed now, and can be turned back
into a normal IS_ENABLED() check. Any driver that gets the dependency
wrong will now cause a link time failure rather than being unable to use
PTP support when that is in a loadable module.

However, the two recently added ptp_get_vclocks_index() and
ptp_convert_timestamp() interfaces are only called from builtin code with
ethtool and socket timestamps, so keep the current behavior by stubbing
those out completely when PTP is in a loadable module. This should be
addressed properly in a follow-up.

As Richard suggested, we may want to actually turn PTP support into a
'bool' option later on, preventing it from being a loadable module
altogether, which would be one way to solve the problem with the ethtool
interface.

Fixes: 06c16d89d2cb ("ice: register 1588 PTP clock device object for E810 devices")
Link: https://lore.kernel.org/netdev/20210804121318.337276-1-arnd@kernel.org/
Link: https://lore.kernel.org/netdev/CAK8P3a06enZOf=XyZ+zcAwBczv41UuCTz+=0FMf2gBz1_cOnZQ@mail.gmail.com/
Link: https://lore.kernel.org/netdev/CAK8P3a3=eOxE-K25754+fB_-i_0BZzf9a9RfPTX3ppSwu9WZXw@mail.gmail.com/
Link: https://lore.kernel.org/netdev/20210726084540.3282344-1-arnd@kernel.org/
Acked-by: Shannon Nelson <snelson@pensando.io>
Acked-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210812183509.1362782-1-arnd@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ptp: add kernel API ptp_convert_timestamp()

Add kernel API ptp_convert_timestamp() to convert raw hardware timestamp
to a specified ptp vclock time.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: add kernel API ptp_get_vclocks_index()

Add kernel API ptp_get_vclocks_index() to get all ptp
vclocks index on pclock.

This is preparation for supporting ptp vclocks info query
through ethtool.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: add ptp virtual clock driver framework

This patch is to add ptp virtual clock driver framework
utilizing timecounter/cyclecounter.

The patch just exports two essential APIs for PTP driver.

- ptp_vclock_register()
- ptp_vclock_unregister()

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: ptp_clock: make scaled_ppm_to_ppb static inline

Make scaled_ppm_to_ppb static inline to be able to build drivers that
use this function even with PTP_1588_CLOCK disabled.

Signed-off-by: Radu Pirea (NXP OSS) <radu-nicolae.pirea@oss.nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: improve max_adj check against unreasonable values

Scaled PPM conversion to PPB may (on 64bit systems) result
in a value larger than s32 can hold (freq/scaled_ppm is a long).
This means the kernel will not correctly reject unreasonably
high ->freq values (e.g. > 4294967295ppb, 281474976645 scaled PPM).

The conversion is equivalent to a division by ~66 (65.536),
so the value of ppb is always smaller than ppm, but not small
enough to assume narrowing the type from long -> s32 is okay.

Note that reasonable user space (e.g. ptp4l) will not use such
high values, anyway, 4289046510ppb ~= 4.3x, so the fix is
somewhat pedantic.

Fixes: d39a743511cd ("ptp: validate the requested frequency adjustment.")
Fixes: d94ba80ebbea ("ptp: Added a brand new class driver for ptp clocks.")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: document struct ptp_clock_request members

It's arguable most people interested in configuring a PPS signal
want it as external output, not as kernel input. PTP_CLK_REQ_PPS
is for input though. Add documentation to nudge readers into
the correct direction.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Link: https://lore.kernel.org/r/20201117213826.18235-1-a.fatoum@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ptp: fix struct member comment for do_aux_work

The do_aux_work callback had documentation in the structure comment
which referred to it as "do_work".

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: Add adjphase function to support phase offset control.

Adds adjust phase function to take advantage of a PHC
clock's hardware filtering capability that uses phase offset
control word instead of frequency offset control word.

Signed-off-by: Vincent Cheng <vincent.cheng.xh@renesas.com>
Reviewed-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: Avoid deadlocks in the programmable pin code.

The PTP Hardware Clock (PHC) subsystem offers an API for configuring
programmable pins. User space sets or gets the settings using ioctls,
and drivers verify dialed settings via a callback. Drivers may also
query pin settings by calling the ptp_find_pin() method.

Although the core subsystem protects concurrent access to the pin
settings, the implementation places illogical restrictions on how
drivers may call ptp_find_pin(). When enabling an auxiliary function
via the .enable(on=1) callback, drivers may invoke the pin finding
method, but when disabling with .enable(on=0) drivers are not
permitted to do so. With the exception of the mv88e6xxx, all of the
PHC drivers do respect this restriction, but still the locking pattern
is both confusing and unnecessary.

This patch changes the locking implementation to allow PHC drivers to
freely call ptp_find_pin() from their .enable() and .verify()
callbacks.

V2 ChangeLog:
- fixed spelling in the kernel doc
- add Vladimir's tested by tag

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Reported-by: Yangbo Lu <yangbo.lu@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: introduce ptp_cancel_worker_sync

In order to effectively use the PTP kernel thread for tasks such as
timestamping packets, allow the user control over stopping it, which is
needed e.g. when the timestamping queues must be drained.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: ptp_clock: Publish scaled_ppm_to_ppb

Publish scaled_ppm_to_ppb to allow drivers to use it.

Signed-off-by: Shalom Toledo <shalomt@mellanox.com>
Reviewed-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61

Based on 1 normalized pattern(s):

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

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 441 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520071858.739733335@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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 <richardcochran@gmail.com>
Cc: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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 <richardcochran@gmail.com>
Cc: Jacob Keller <jacob.e.keller@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: introduce ptp auxiliary worker

Many PTP drivers required to perform some asynchronous or periodic work,
like periodically handling PHC counter overflow or handle delayed timestamp
for RX/TX network packets. In most of the cases, such work is implemented
using workqueues. Unfortunately, Kernel workqueues might introduce
significant delay in work scheduling under high system load and on -RT,
which could cause misbehavior of PTP drivers due to internal counter
overflow, for example, and there is no way to tune its execution policy and
priority manuallly.

Hence, The kthread_worker can be used insted of workqueues, as it create
separte named kthread for each worker and its its execution policy and
priority can be configured using chrt tool.

This prblem was reported for two drivers TI CPSW CPTS and dp83640, so
instead of modifying each of these driver it was proposed to add PTP
auxiliary worker to the PHC subsystem.

The patch adds PTP auxiliary worker in PHC subsystem using kthread_worker
and kthread_delayed_work and introduces two new PHC subsystem APIs:

- long (*do_aux_work)(struct ptp_clock_info *ptp) callback in
ptp_clock_info structure, which driver should assign if it require to
perform asynchronous or periodic work. Driver should return the delay of
the PTP next auxiliary work scheduling time (>=0) or negative value in case
further scheduling is not required.

- int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay) which
allows schedule PTP auxiliary work.

The name of kthread_worker thread corresponds PTP PHC device name "ptp%d".

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp_clock: Allow for it to be optional

In order to break the hard dependency between the PTP clock subsystem and
ethernet drivers capable of being clock providers, this patch provides
simple PTP stub functions to allow linkage of those drivers into the
kernel even when the PTP subsystem is configured out. Drivers must be
ready to accept NULL from ptp_clock_register() in that case.

And to make it possible for PTP to be configured out, the select statement
in those driver's Kconfig menu entries is converted to the new "imply"
statement. This way the PTP subsystem may have Kconfig dependencies of
its own, such as POSIX_TIMERS, without having to make those ethernet
drivers unavailable if POSIX timers are cconfigured out. And when support
for POSIX timers is selected again then the default config option for PTP
clock support will automatically be adjusted accordingly.

The pch_gbe driver is a bit special as it relies on extra code in
drivers/ptp/ptp_pch.c. Therefore we let the make process descend into
drivers/ptp/ even if PTP_1588_CLOCK is unselected.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: Edward Cree <ecree@solarflare.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Cc: Paul Bolle <pebolle@tiscali.nl>
Cc: linux-kbuild@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: Michal Marek <mmarek@suse.com>
Link: http://lkml.kernel.org/r/1478841010-28605-4-git-send-email-nicolas.pitre@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

ptp: Introduce a high resolution frequency adjustment method.

The internal PTP Hardware Clock (PHC) interface limits the resolution for
frequency adjustments to one part per billion. However, some hardware
devices allow finer adjustment, and making use of the increased resolution
improves synchronization measurably on such devices.

This patch adds an alternative method that allows finer frequency tuning
by passing the scaled ppm value to PHC drivers. This value comes from
user space, and it has a resolution of about 0.015 ppb. We also deprecate
the older method, anticipating its removal once existing drivers have been
converted over.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Suggested-by: Ulrik De Bie <ulrik.debie-os@e2big.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp_clock: future-proofing drivers against PTP subsystem becoming optional

Drivers must be ready to accept NULL from ptp_clock_register() if the
PTP clock subsystem is configured out.

This patch documents that and ensures that all drivers cope well
with a NULL return.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Eugenia Emantayev <eugenia@mellanox.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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>

ptp: remove 32 bit get/set methods.

All of the PHC drivers have been converted to the new methods. This patch
converts the three remaining callers within the core code and removes the
older methods for good. As a result, the core PHC code is ready for the
year 2038. However, some of the PHC drivers are not quite ready yet.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: introduce get/set time methods with explicit 64 bit seconds.

Converting the PHC drivers over to the new methods is one step along the
way to making them ready for 2038. Once all the drivers are up to date,
then the old methods will be removed.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: introduce programmable pins.

This patch adds a pair of new ioctls to the PTP Hardware Clock device
interface. Using the ioctls, user space programs can query each pin to
find out its current function and also reprogram a different function
if desired.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: update adjfreq callback description

This patch updates the adjfreq callback description to include a note that the
delta in ppb is always relative to the base frequency, and not to the current
frequency of the hardware clock.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
CC: stable@vger.kernel.org [v3.5+]
CC: Richard Cochran <richard.cochran@gmail.com>
CC: John Stultz <john.stultz@linaro.org>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: clarify the clock_name sysfs attribute

There has been some confusion among PHC driver authors about the
intended purpose of the clock_name attribute. This patch expands the
documation in order to clarify how the clock_name field should be
understood.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ptp: link the phc device to its parent device

PTP Hardware Clock devices appear as class devices in sysfs. This patch
changes the registration API to use the parent device, clarifying the
clock's relationship to the underlying device.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

pps/ptp: Allow PHC devices to adjust PPS events for known delay

Initial version by Stuart Hodgson <smhodgson@solarflare.com>

Some PHC device drivers may deliver PPS events with a significant
and variable delay, but still be able to measure precisely what
that delay is.

Add a pps_sub_ts() function for subtracting a delay from the
timestamp(s) in a PPS event, and a PTP event type (PTP_CLOCK_PPSUSR)
for which the caller provides a complete PPS event.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

ptp: Add a method for obtaining the device index.

This commit adds a method that MAC drivers may call in order to find out
the device number of their associated PTP Hardware Clock.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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 <richard.cochran@omicron.at>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: John Stultz <john.stultz@linaro.org>