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[net-next,v2,0/2] net: stmmac: Increase clk_ptp_ref rate

Message ID 20230725211853.895832-2-ahalaney@redhat.com
Headers
Series net: stmmac: Increase clk_ptp_ref rate |

Message

Andrew Halaney July 25, 2023, 9:04 p.m. UTC 
  This series aims to increase the clk_ptp_ref rate to get the best
possible PTP timestamping resolution possible. Some modified disclosure
about my development/testing process from the RFC/RFT v1 follows.

Disclosure: I don't know much about PTP beyond what you can google in an
afternoon, don't have access to documentation about the stmmac IP,
and have only tested that (based on code comments and git commit
history) the programming of the subsecond register (and the clock rate)
makes more sense with these changes. Qualcomm has tested a similar
change offlist, verifying PTP more formally as I understand it.

The last version was an RFC/RFT, but I didn't get a lot of confirmation
that doing patch 3 in that series (essentially setting clk_ptp_ref to
whatever its max value is) for the whole stmmac ecosystem was a safe
idea. So I am erring on the side of caution and doing this for the
Qualcomm platform only. See v1 for an approach that would apply to
all stmmac platform drivers with clk_ptp_ref.

v1: https://lore.kernel.org/netdev/20230711205732.364954-1-ahalaney@redhat.com/
Changes since v1:
    - Collected Reviewed-by tags (Simon)
    - Dropped RFC/RFT, dropped patch 3 that implemented this rate
      change at a stmmac platform level

Andrew Halaney (2):
  net: stmmac: Make ptp_clk_freq_config variable type explicit
  net: stmmac: dwmac-qcom-ethqos: Use max frequency for clk_ptp_ref

 .../net/ethernet/stmicro/stmmac/dwmac-intel.c  |  3 +--
 .../stmicro/stmmac/dwmac-qcom-ethqos.c         | 18 ++++++++++++++++++
 include/linux/stmmac.h                         |  4 +++-
 3 files changed, 22 insertions(+), 3 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org July 28, 2023, 3:40 a.m. UTC | #1 
Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue, 25 Jul 2023 16:04:24 -0500 you wrote:
> This series aims to increase the clk_ptp_ref rate to get the best
> possible PTP timestamping resolution possible. Some modified disclosure
> about my development/testing process from the RFC/RFT v1 follows.
> 
> Disclosure: I don't know much about PTP beyond what you can google in an
> afternoon, don't have access to documentation about the stmmac IP,
> and have only tested that (based on code comments and git commit
> history) the programming of the subsecond register (and the clock rate)
> makes more sense with these changes. Qualcomm has tested a similar
> change offlist, verifying PTP more formally as I understand it.
> 
> [...]

Here is the summary with links:
  - [net-next,v2,1/2] net: stmmac: Make ptp_clk_freq_config variable type explicit
    https://git.kernel.org/netdev/net-next/c/d928d14be651
  - [net-next,v2,2/2] net: stmmac: dwmac-qcom-ethqos: Use max frequency for clk_ptp_ref
    https://git.kernel.org/netdev/net-next/c/db845b9b2040

You are awesome, thank you!