Message-ID: <CAACQVJomhn1p2L=ZQakwSRXAci2oK0EG0HQsTVhRz6NLFZEHqw@mail.gmail.com>
Date:   Mon, 1 Jun 2020 21:01:42 +0530
From:   Vasundhara Volam <vasundhara-v.volam@...adcom.com>
To:     Jiri Pirko <jiri@...nulli.us>
Cc:     David Miller <davem@...emloft.net>,
        Netdev <netdev@...r.kernel.org>,
        Michael Chan <michael.chan@...adcom.com>
Subject: Re: [PATCH v3 net-next 0/6] bnxt_en: Add 'enable_live_dev_reset' and
 'allow_live_dev_reset' generic devlink params.

On Mon, Jun 1, 2020 at 3:34 PM Jiri Pirko <jiri@...nulli.us> wrote:
>
> Mon, Jun 01, 2020 at 10:58:09AM CEST, vasundhara-v.volam@...adcom.com wrote:
> >On Mon, Jun 1, 2020 at 12:13 PM Jiri Pirko <jiri@...nulli.us> wrote:
> >>
> >> Mon, Jun 01, 2020 at 08:18:19AM CEST, jiri@...nulli.us wrote:
> >> >Sun, May 31, 2020 at 09:03:39AM CEST, vasundhara-v.volam@...adcom.com wrote:
> >> >>Live device reset capability allows the users to reset the device in real
> >> >>time. For example, after flashing a new firmware image, this feature allows
> >> >>a user to initiate the reset immediately from a separate command, to load
> >> >>the new firmware without reloading the driver or resetting the system.
> >> >>
> >> >>When device reset is initiated, services running on the host interfaces
> >> >>will momentarily pause and resume once reset is completed, which is very
> >> >>similar to momentary network outage.
> >> >>
> >> >>This patchset adds support for two new generic devlink parameters for
> >> >>controlling the live device reset capability and use it in the bnxt_en
> >> >>driver.
> >> >>
> >> >>Users can initiate the reset from a separate command, for example,
> >> >>'ethtool --reset ethX all' or 'devlink dev reload' to reset the
> >> >>device.
> >> >>Where ethX or dev is any PF with administrative privileges.
> >> >>
> >> >>Patchset also updates firmware spec. to 1.10.1.40.
> >> >>
> >> >>
> >> >>v2->v3: Split the param into two new params "enable_live_dev_reset" and
> >> >
> >> >Vasundhara, I asked you multiple times for this to be "devlink dev reload"
> >> >attribute. I don't recall you telling any argument against it. I belive
> >> >that this should not be paramater. This is very tightly related to
> >> >reload, could you please have it as an attribute of reload, as I
> >> >suggested?
> >>
> >> I just wrote the thread to the previous version. I understand now why
> >> you need param as you require reboot to activate the feature.
> >
> >Okay.
> >>
> >> However, I don't think it is correct to use enable_live_dev_reset to
> >> indicate the live-reset capability to the user. Params serve for
> >> configuration only. Could you please move the indication some place
> >> else? ("devlink dev info" seems fitting).
> >
> >Here we are not indicating the support. If the parameter is set to
> >true, we are enabling the feature in firmware and driver after reboot.
> >Users can disable the feature by setting the parameter to false and
> >reboot. This is the configuration which is enabling or disabling the
> >feature in the device.
> >
> >>
> >> I think that you can do the indication in a follow-up patchset. But
> >> please remove it from this one where you do it with params.
> >
> >Could you please see the complete patchset and use it bnxt_en driver
> >to get a clear picture? We are not indicating the support.
>
> Right. I see.
>
> There is still one thing that I see problematic. There is no clear
> semantics on when the "live fw update" is going to be performed. You
> enable the feature in NVRAM and you set to "allow" it from all the host.
> Now the user does reset, the driver has 2 options:
> 1) do the live fw reset
> 2) do the ordinary fw reset
>
> This specification is missing and I believe it should be part of this
> patchset, otherwise the behaviour might not be deterministic between
> drivers and driver versions.

I see, this makes sense. It takes little time for me to extend
"devlink dev reload". I will spend time on it and send the next
version with 'devlink dev reload' patches included.

>
> I think that the legacy ethtool should stick with the "ordinary fw reset",
> becase that is what user expects. You should add an attribute to
> "devlink dev reload" to trigger the "live fw reset"

Okay.

I am planning to add a type field with "driver-only | fw-reset |
live-fw-reset | live-fw-patch" to "devlink dev reload" command.

driver-only - Resets host driver instance of the 'devlink dev'
(current behaviour). This will be default, if the user does not
provide the type option.
fw-reset - Initiate the reset command for the currently running
firmware and wait for the driver reload for completing the reset.
(This is similar to the legacy "ethtool --reset all" command).
live-fw-reset - Resets the currently running firmware and driver entities.
live-fw-patch - Loads the currently pending flashed firmware and
reloads all driver entities. If no pending flashed firmware, resets
currently loaded firmware.

Thanks.
>
>
>
> >
> >Thanks.
> >
> >>
> >>
> >> >
> >> >Thanks!
> >> >
> >> >
> >> >>"allow_live_dev_reset".
> >> >>- Expand the documentation of each param and update commit messages
> >> >> accordingly.
> >> >>- Separated the permanent configuration mode code to another patch and
> >> >>rename the callbacks of the "allow_live_dev_reset" parameter accordingly.
> >> >>
> >> >>v1->v2: Rename param to "allow_fw_live_reset" from "enable_hot_fw_reset".
> >> >>- Update documentation files and commit messages with more details of the
> >> >> feature.
> >> >>
> >> >>Vasundhara Volam (6):
> >> >>  devlink: Add 'enable_live_dev_reset' generic parameter.
> >> >>  devlink: Add 'allow_live_dev_reset' generic parameter.
> >> >>  bnxt_en: Use 'enable_live_dev_reset' devlink parameter.
> >> >>  bnxt_en: Update firmware spec. to 1.10.1.40.
> >> >>  bnxt_en: Use 'allow_live_dev_reset' devlink parameter.
> >> >>  bnxt_en: Check if fw_live_reset is allowed before doing ETHTOOL_RESET
> >> >>
> >> >> Documentation/networking/devlink/bnxt.rst          |  4 ++
> >> >> .../networking/devlink/devlink-params.rst          | 28 ++++++++++
> >> >> drivers/net/ethernet/broadcom/bnxt/bnxt.c          | 28 +++++++++-
> >> >> drivers/net/ethernet/broadcom/bnxt/bnxt.h          |  2 +
> >> >> drivers/net/ethernet/broadcom/bnxt/bnxt_devlink.c  | 49 +++++++++++++++++
> >> >> drivers/net/ethernet/broadcom/bnxt/bnxt_devlink.h  |  1 +
> >> >> drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c  | 17 +++---
> >> >> drivers/net/ethernet/broadcom/bnxt/bnxt_hsi.h      | 64 +++++++++++++---------
> >> >> include/net/devlink.h                              |  8 +++
> >> >> net/core/devlink.c                                 | 10 ++++
> >> >> 10 files changed, 175 insertions(+), 36 deletions(-)
> >> >>
> >> >>--
> >> >>1.8.3.1
> >> >>

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