[Intel-wired-lan] [net-next PATCH v2 0/9] implement support for PTP on E822 hardware

Keller, Jacob E jacob.e.keller at intel.com
Tue Oct 12 21:29:57 UTC 2021


On 10/11/2021 6:07 PM, Keller, Jacob E wrote:
> Extend the ice driver implementation to support PTP for the E822 based
> devices.
> 
> This includes a few cleanup patches, that fix some minor issues spotted
> while preparing them. In addition, there are some slight refactors to ease
> the addition of E822 support, followed by adding the new hardware
> implementation ice_ptp_hw.c.
> 
> There are a few major differences with E822 support compared to E810
> support:
> 
> *) The E822 device has a Clock Generation Unit which must be initialized in
> order to generate proper clock frequencies on the output that drives the PTP
> hardware clock registers
> 
> *) The E822 PHY is a bit different and requires a more complex
> initialization procedure which must be rerun any time the link configuration
> changes.
> 
> *) The E822 devices support enhanced timestamp calibration by making use of
> a process called Vernier offset measurement. This allows the hardware to
> measure phase offset related to the PHY clocks for Serdes and FEC, reducing
> the inaccuracy of the timestamp relative to the actual packet transmission
> and receipt. Making use of this requires data gathered from the first
> transmitted and received packets, and waiting for the PHY to complete the
> calibration measurements. This is done as part of a new kthread, ov_work.
> Note that to avoid delay in enabling timestamps, we start the PHY in
> 'bypass' mode which allows timestamps to be captured without the Vernier
> calibration measurement. Once the first packets have been sent and received,
> we then complete the calibration setup and exit bypass mode and begin using
> the more precise timestamps. According to the datasheet, timestamps without
> calibration data can be incorrect relative to actual receipt or transmission
> by up to 1 clock cycle (~1.25 nanoseconds), while calibrated timestamps
> should be correct to within 1/8th of a clock cycle (~0.15 nanoseconds).
> 
> *) E822 devices support crosstimestamping via PCIe PTM, which we enable when
> available on the platform.
> 
> There is a fair amount of logic required to perform PHY and CGU
> initialization, which is the vast majority of the new code, but it is fairly
> self contained within ice_ptp_hw.c, with the exception of monitoring for
> offset validity being handled by a kthread.
> 
> Changes since v1 resend:
> * Restore the ICE_HWTS config that got dropped when regenerating the series.
> 
> Changes since previous submission (v3):
> * Fix a bug with SIOCSHWTSTAMP failing to update returned filter to
>   HWTSTAMP_FILTER_ALL
> * Fix an issue with the Tx timestamp slot assignment using modulo instead
>   of division
> * Rebased on top of Intel Wired LAN dev-queue
> * Dropped the patches which were previously applied as fixes
> 
> Changes since v2:
> * introduced helper functions to enable and disable clock outputs
> 
> Changes since v1:
> * Fixed build against non-X86 arch for the PCIe PTM support
> 
> 
> Jacob Keller (9):
>   ice: introduce ice_base_incval function
>   ice: PTP: move setting of tstamp_config
>   ice: use 'int err' instead of 'int status' in ice_ptp_hw.c
>   ice: introduce ice_ptp_init_phc function
>   ice: convert clk_freq capability into time_ref
>   ice: implement basic E822 PTP support
>   ice: ensure the hardware Clock Generation Unit is configured
>   ice: exit bypass mode once hardware finishes timestamp calibration
>   ice: support crosstimestamping on E822 devices if supported
> 
>  drivers/net/ethernet/intel/Kconfig            |   10 +
>  drivers/net/ethernet/intel/ice/ice_cgu_regs.h |  116 +
>  drivers/net/ethernet/intel/ice/ice_common.c   |   12 +
>  .../net/ethernet/intel/ice/ice_hw_autogen.h   |    9 +
>  drivers/net/ethernet/intel/ice/ice_main.c     |    7 +
>  drivers/net/ethernet/intel/ice/ice_ptp.c      |  655 +++-
>  drivers/net/ethernet/intel/ice/ice_ptp.h      |   30 +-
>  .../net/ethernet/intel/ice/ice_ptp_consts.h   |  374 +++
>  drivers/net/ethernet/intel/ice/ice_ptp_hw.c   | 2794 ++++++++++++++++-
>  drivers/net/ethernet/intel/ice/ice_ptp_hw.h   |  345 ++
>  drivers/net/ethernet/intel/ice/ice_type.h     |   23 +-
>  11 files changed, 4174 insertions(+), 201 deletions(-)
>  create mode 100644 drivers/net/ethernet/intel/ice/ice_cgu_regs.h
>  create mode 100644 drivers/net/ethernet/intel/ice/ice_ptp_consts.h
> 
> 
> base-commit: 2d82122b64363fe17521f26b63a7c89b204d17eb
> 

Due to a rebasing error, this series still has a few ice_status mixups.
I've fixed these and double checked everything and am re-sending a v3
with also the small fixups noted by Paul Menzel! Thanks for the review!

Regards,
Jake



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