Date:   Thu, 8 Dec 2022 16:23:09 -0800
From:   Saeed Mahameed <saeed@...nel.org>
To:     Tony Nguyen <anthony.l.nguyen@...el.com>
Cc:     davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
        edumazet@...gle.com, netdev@...r.kernel.org,
        jacob.e.keller@...el.com, richardcochran@...il.com, leon@...nel.org
Subject: Re: [PATCH net-next v3 00/14][pull request] Intel Wired LAN Driver
 Updates 2022-12-08 (ice)

On 08 Dec 13:39, Tony Nguyen wrote:
>Jacob Keller says:
>
>This series of patches primarily consists of changes to fix some corner
>cases that can cause Tx timestamp failures. The issues were discovered and
>reported by Siddaraju DH and primarily affect E822 hardware, though this
>series also includes some improvements that affect E810 hardware as well.
>
>The primary issue is regarding the way that E822 determines when to generate
>timestamp interrupts. If the driver reads timestamp indexes which do not
>have a valid timestamp, the E822 interrupt tracking logic can get stuck.
>This is due to the way that E822 hardware tracks timestamp index reads
>internally. I was previously unaware of this behavior as it is significantly
>different in E810 hardware.
>
>Most of the fixes target refactors to ensure that the ice driver does not
>read timestamp indexes which are not valid on E822 hardware. This is done by
>using the Tx timestamp ready bitmap register from the PHY. This register
>indicates what timestamp indexes have outstanding timestamps waiting to be
>captured.
>
>Care must be taken in all cases where we read the timestamp registers, and
>thus all flows which might have read these registers are refactored. The
>ice_ptp_tx_tstamp function is modified to consolidate as much of the logic
>relating to these registers as possible. It now handles discarding stale
>timestamps which are old or which occurred after a PHC time update. This
>replaces previously standalone thread functions like the periodic work
>function and the ice_ptp_flush_tx_tracker function.
>
>In addition, some minor cleanups noticed while writing these refactors are
>included.
>
>The remaining patches refactor the E822 implementation to remove the
>"bypass" mode for timestamps. The E822 hardware has the ability to provide a
>more precise timestamp by making use of measurements of the precise way that
>packets flow through the hardware pipeline. These measurements are known as
>"Vernier" calibration. The "bypass" mode disables many of these measurements
>in favor of a faster start up time for Tx and Rx timestamping. Instead, once
>these measurements were captured, the driver tries to reconfigure the PHY to
>enable the vernier calibrations.
>
>Unfortunately this recalibration does not work. Testing indicates that the
>PHY simply remains in bypass mode without the increased timestamp precision.
>Remove the attempt at recalibration and always use vernier mode. This has
>one disadvantage that Tx and Rx timestamps cannot begin until after at least
>one packet of that type goes through the hardware pipeline. Because of this,
>further refactor the driver to separate Tx and Rx vernier calibration.
>Complete the Tx and Rx independently, enabling the appropriate type of
>timestamp as soon as the relevant packet has traversed the hardware
>pipeline. This was reported by Milena Olech.
>
>Note that although these might be considered "bug fixes", the required
>changes in order to appropriately resolve these issues is large. Thus it
>does not feel suitable to send this series to net.
>---
>v3:
>- Dropped patch 'ice: disable Tx timestamps while link is down'
>- Use bitmap_or function over for_each_set_bit
>- Change incorrect function name (ice_ptp_tstamp_tx()) to correct one
>(ice_ptp_tx_tstamp()) in patch 9 commit message
>

LGTM

Reviewed-by: Saeed Mahameed <saeed@...nel.org>

>v2: https://lore.kernel.org/netdev/20221207210937.1099650-1-anthony.l.nguyen@intel.com/
>- Dropped incorrect/useless locking around init in ice_ptp_tx_tstamp
>- Added patch to call sychronize_irq during teardown of Tx tracker
>- Renamed and refactored "ts_handled" into "more_timestamps" for clarity
>- Moved all initialization of Tx tracker to before spin_lock_init
>- Initialize raw_stamp to 0 and add check that it has been set
>
>v1: https://lore.kernel.org/netdev/20221130194330.3257836-1-anthony.l.nguyen@intel.com/
>
>The following are changes since commit bde55dd9ccda7a3f5f735d89e855691362745248:
>  net: dsa: microchip: add stats64 support for ksz8 series of switches
>and are available in the git repository at:
>  git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next-queue 100GbE
>
>Jacob Keller (10):
>  ice: fix misuse of "link err" with "link status"
>  ice: always call ice_ptp_link_change and make it void
>  ice: handle discarding old Tx requests in ice_ptp_tx_tstamp
>  ice: check Tx timestamp memory register for ready timestamps
>  ice: synchronize the misc IRQ when tearing down Tx tracker
>  ice: protect init and calibrating check in ice_ptp_request_ts
>  ice: cleanup allocations in ice_ptp_alloc_tx_tracker
>  ice: handle flushing stale Tx timestamps in ice_ptp_tx_tstamp
>  ice: only check set bits in ice_ptp_flush_tx_tracker
>  ice: reschedule ice_ptp_wait_for_offset_valid during reset
>
>Karol Kolacinski (1):
>  ice: Reset TS memory for all quads
>
>Milena Olech (1):
>  ice: Remove the E822 vernier "bypass" logic
>
>Sergey Temerkhanov (1):
>  ice: Use more generic names for ice_ptp_tx fields
>
>Siddaraju DH (1):
>  ice: make Tx and Rx vernier offset calibration independent
>
> drivers/net/ethernet/intel/ice/ice_main.c   |   9 +-
> drivers/net/ethernet/intel/ice/ice_ptp.c    | 546 ++++++++++----------
> drivers/net/ethernet/intel/ice/ice_ptp.h    |  39 +-
> drivers/net/ethernet/intel/ice/ice_ptp_hw.c | 336 ++++++------
> drivers/net/ethernet/intel/ice/ice_ptp_hw.h |   8 +-
> 5 files changed, 463 insertions(+), 475 deletions(-)
>
>-- 
>2.35.1
>

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