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linux/drivers/ptp/Kconfig
David Woodhouse 2050327242 ptp: Add support for the AMZNC10C 'vmclock' device 
The vmclock device addresses the problem of live migration with
precision clocks. The tolerances of a hardware counter (e.g. TSC) are
typically around ±50PPM. A guest will use NTP/PTP/PPS to discipline that
counter against an external source of 'real' time, and track the precise
frequency of the counter as it changes with environmental conditions.

When a guest is live migrated, anything it knows about the frequency of
the underlying counter becomes invalid. It may move from a host where
the counter running at -50PPM of its nominal frequency, to a host where
it runs at +50PPM. There will also be a step change in the value of the
counter, as the correctness of its absolute value at migration is
limited by the accuracy of the source and destination host's time
synchronization.

In its simplest form, the device merely advertises a 'disruption_marker'
which indicates that the guest should throw away any NTP synchronization
it thinks it has, and start again.

Because the shared memory region can be exposed all the way to userspace
through the /dev/vmclock0 node, applications can still use time from a
fast vDSO 'system call', and check the disruption marker to be sure that
their timestamp is indeed truthful.

The structure also allows for the precise time, as known by the host, to
be exposed directly to guests so that they don't have to wait for NTP to
resync from scratch. The PTP driver consumes this information if present.
Like the KVM PTP clock, this PTP driver can convert TSC-based cross
timestamps into KVM clock values. Unlike the KVM PTP clock, it does so
only when such is actually helpful.

The values and fields are based on the nascent virtio-rtc specification,
and the intent is that a version (hopefully precisely this version) of
this structure will be included as an optional part of that spec. In the
meantime, this driver supports the simple ACPI form of the device which
is being shipped in certain commercial hypervisors (and submitted for
inclusion in QEMU).

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2024-10-09 12:16:18 +01:00

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# SPDX-License-Identifier: GPL-2.0-only
#
# PTP clock support configuration
#
menu "PTP clock support"
config PTP_1588_CLOCK
tristate "PTP clock support"
depends on NET && POSIX_TIMERS
default ETHERNET
select PPS
select NET_PTP_CLASSIFY
help
The IEEE 1588 standard defines a method to precisely
synchronize distributed clocks over Ethernet networks. The
standard defines a Precision Time Protocol (PTP), which can
be used to achieve synchronization within a few dozen
microseconds. In addition, with the help of special hardware
time stamping units, it can be possible to achieve
synchronization to within a few hundred nanoseconds.
This driver adds support for PTP clocks as character
devices. If you want to use a PTP clock, then you should
also enable at least one clock driver as well.
To compile this driver as a module, choose M here: the module
will be called ptp.
config PTP_1588_CLOCK_OPTIONAL
tristate
default y if PTP_1588_CLOCK=n
default PTP_1588_CLOCK
help
Drivers that can optionally use the PTP_1588_CLOCK framework
should depend on this symbol to prevent them from being built
into vmlinux while the PTP support itself is in a loadable
module.
If PTP support is disabled, this dependency will still be
met, and drivers refer to dummy helpers.
config PTP_1588_CLOCK_DTE
tristate "Broadcom DTE as PTP clock"
depends on PTP_1588_CLOCK
depends on NET && HAS_IOMEM
depends on ARCH_BCM_MOBILE || (ARCH_BCM_IPROC && !(ARCH_BCM_NSP || ARCH_BCM_5301X)) || COMPILE_TEST
default y
help
This driver adds support for using the Digital timing engine
(DTE) in the Broadcom SoC's as a PTP clock.
The clock can be used in both wired and wireless networks
for PTP purposes.
To compile this driver as a module, choose M here: the module
will be called ptp_dte.
config PTP_1588_CLOCK_QORIQ
tristate "Freescale QorIQ 1588 timer as PTP clock"
depends on GIANFAR || FSL_DPAA_ETH || FSL_DPAA2_ETH || FSL_ENETC || FSL_ENETC_VF || COMPILE_TEST
depends on PTP_1588_CLOCK
default y
help
This driver adds support for using the Freescale QorIQ 1588
timer as a PTP clock. This clock is only useful if your PTP
programs are getting hardware time stamps on the PTP Ethernet
packets using the SO_TIMESTAMPING API.
To compile this driver as a module, choose M here: the module
will be called ptp-qoriq.
comment "Enable PHYLIB and NETWORK_PHY_TIMESTAMPING to see the additional clocks."
depends on PHYLIB=n || NETWORK_PHY_TIMESTAMPING=n
config DP83640_PHY
tristate "Driver for the National Semiconductor DP83640 PHYTER"
depends on NETWORK_PHY_TIMESTAMPING
depends on PHYLIB
depends on PTP_1588_CLOCK
select CRC32
help
Supports the DP83640 PHYTER with IEEE 1588 features.
This driver adds support for using the DP83640 as a PTP
clock. This clock is only useful if your PTP programs are
getting hardware time stamps on the PTP Ethernet packets
using the SO_TIMESTAMPING API.
In order for this to work, your MAC driver must also
implement the skb_tx_timestamp() function.
config PTP_1588_CLOCK_INES
tristate "ZHAW InES PTP time stamping IP core"
depends on NETWORK_PHY_TIMESTAMPING
depends on HAS_IOMEM
depends on PHYLIB
depends on PTP_1588_CLOCK
help
This driver adds support for using the ZHAW InES 1588 IP
core. This clock is only useful if the MII bus of your MAC
is wired up to the core.
config PTP_1588_CLOCK_PCH
tristate "Intel PCH EG20T as PTP clock"
depends on MIPS_GENERIC || X86_32 || COMPILE_TEST
depends on HAS_IOMEM && PCI
depends on NET
depends on PTP_1588_CLOCK
help
This driver adds support for using the PCH EG20T as a PTP
clock. The hardware supports time stamping of PTP packets
when using the end-to-end delay (E2E) mechanism. The peer
delay mechanism (P2P) is not supported.
This clock is only useful if your PTP programs are getting
hardware time stamps on the PTP Ethernet packets using the
SO_TIMESTAMPING API.
To compile this driver as a module, choose M here: the module
will be called ptp_pch.
config PTP_1588_CLOCK_KVM
tristate "KVM virtual PTP clock"
depends on PTP_1588_CLOCK
depends on (KVM_GUEST && X86) || (HAVE_ARM_SMCCC_DISCOVERY && ARM_ARCH_TIMER)
default y
help
This driver adds support for using kvm infrastructure as a PTP
clock. This clock is only useful if you are using KVM guests.
To compile this driver as a module, choose M here: the module
will be called ptp_kvm.
config PTP_1588_CLOCK_VMCLOCK
tristate "Virtual machine PTP clock"
depends on X86_TSC || ARM_ARCH_TIMER
depends on PTP_1588_CLOCK && ACPI && ARCH_SUPPORTS_INT128
default y
help
This driver adds support for using a virtual precision clock
advertised by the hypervisor. This clock is only useful in virtual
machines where such a device is present.
To compile this driver as a module, choose M here: the module
will be called ptp_vmclock.
config PTP_1588_CLOCK_IDT82P33
tristate "IDT 82P33xxx PTP clock"
depends on PTP_1588_CLOCK && I2C
default n
help
This driver adds support for using the IDT 82P33xxx as a PTP
clock. This clock is only useful if your time stamping MAC
is connected to the IDT chip.
To compile this driver as a module, choose M here: the module
will be called ptp_idt82p33.
config PTP_1588_CLOCK_IDTCM
tristate "IDT CLOCKMATRIX as PTP clock"
depends on PTP_1588_CLOCK && I2C
default n
help
This driver adds support for using IDT CLOCKMATRIX(TM) as a PTP
clock. This clock is only useful if your time stamping MAC
is connected to the IDT chip.
To compile this driver as a module, choose M here: the module
will be called ptp_clockmatrix.
config PTP_1588_CLOCK_FC3W
tristate "RENESAS FemtoClock3 Wireless as PTP clock"
depends on PTP_1588_CLOCK && I2C
default n
help
This driver adds support for using Renesas FemtoClock3 Wireless
as a PTP clock. This clock is only useful if your time stamping
MAC is connected to the RENESAS chip.
To compile this driver as a module, choose M here: the module
will be called ptp_fc3.
config PTP_1588_CLOCK_MOCK
tristate "Mock-up PTP clock"
depends on PTP_1588_CLOCK
help
This driver offers a set of PTP clock manipulation operations over
the system monotonic time. It can be used by virtual network device
drivers to emulate PTP capabilities.
To compile this driver as a module, choose M here: the module
will be called ptp_mock.
config PTP_1588_CLOCK_VMW
tristate "VMware virtual PTP clock"
depends on ACPI && HYPERVISOR_GUEST && X86
depends on PTP_1588_CLOCK
help
This driver adds support for using VMware virtual precision
clock device as a PTP clock. This is only useful in virtual
machines running on VMware virtual infrastructure.
To compile this driver as a module, choose M here: the module
will be called ptp_vmw.
config PTP_1588_CLOCK_OCP
tristate "OpenCompute TimeCard as PTP clock"
depends on PTP_1588_CLOCK
depends on HAS_IOMEM && PCI
depends on I2C && MTD
depends on SERIAL_8250
depends on !S390
depends on COMMON_CLK
select NET_DEVLINK
select CRC16
select DPLL
help
This driver adds support for an OpenCompute time card.
The OpenCompute time card is an atomic clock along with
a GPS receiver that provides a Grandmaster clock source
for a PTP enabled network.
More information is available at http://www.timingcard.com/
config PTP_DFL_TOD
tristate "FPGA DFL ToD Driver"
depends on FPGA_DFL
depends on PTP_1588_CLOCK
help
The DFL (Device Feature List) device driver for the Intel ToD
(Time-of-Day) device in FPGA card. The ToD IP within the FPGA
is exposed as PTP Hardware Clock (PHC) device to the Linux PTP
stack to synchronize the system clock to its ToD information
using phc2sys utility of the Linux PTP stack.
To compile this driver as a module, choose M here: the module
will be called ptp_dfl_tod.
endmenu
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