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From:   Saravana Kannan <saravanak@google.com>
Date:   Fri, 24 Feb 2023 22:24:59 -0800
Message-ID: <CAGETcx8iR20dtrKMu+5VdqqTG8xYY7PFjLnkgUfvMNV2bmfhkw@mail.gmail.com>
Subject: Re: [PATCH v3 00/12] fw_devlink improvements
To:     Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Cristian Marussi <cristian.marussi@arm.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <brgl@bgdev.pl>,
        Thomas Gleixner <tglx@linutronix.de>,
        Marc Zyngier <maz@kernel.org>, Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Magnus Damm <magnus.damm@gmail.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Daniel Scally <djrscally@gmail.com>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Len Brown <lenb@kernel.org>,
        =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= <rafal@milecki.pl>,
        Abel Vesa <abel.vesa@linaro.org>,
        Alexander Stein <alexander.stein@ew.tq-group.com>,
        Tony Lindgren <tony@atomide.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        John Stultz <jstultz@google.com>,
        Doug Anderson <dianders@chromium.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Maxim Kiselev <bigunclemax@gmail.com>,
        Maxim Kochetkov <fido_max@inbox.ru>,
        Luca Weiss <luca.weiss@fairphone.com>,
        Colin Foster <colin.foster@in-advantage.com>,
        Martin Kepplinger <martin.kepplinger@puri.sm>,
        Jean-Philippe Brucker <jpb@kernel.org>,
        Vladimir Oltean <vladimir.oltean@nxp.com>,
        kernel-team@android.com, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-gpio@vger.kernel.org,
        linux-mtd@lists.infradead.org, devicetree@vger.kernel.org,
        linux-renesas-soc@vger.kernel.org, linux-acpi@vger.kernel.org
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On Wed, Feb 15, 2023 at 7:12 PM Dmitry Baryshkov
<dmitry.baryshkov@linaro.org> wrote:
>
> On 07/02/2023 03:41, Saravana Kannan wrote:
> > Naresh, Tony, Abel, Geert, Dmitry, Maxim(s), Miquel, Luca, Doug, Martin,
> > Jean-Philippe,
> >
> > Can I get your Tested-by's for this v3 series please?
> >
> > Vladimir,
> >
> > Ccing you because DSA's and fw_devlink have known/existing problems
> > (still in my TODOs to fix). But I want to make sure this series doesn't
> > cause additional problems for DSA.
> >
> > All,
> >
> > This patch series improves fw_devlink in the following ways:
> >
> > 1. It no longer cares about a fwnode having a "compatible" property. It
> >     figures this out more dynamically. The only expectation is that
> >     fwnodes that are converted to devices actually get probed by a driver
> >     for the dependencies to be enforced correctly.
> >
> > 2. Finer grained dependency tracking. fw_devlink will now create device
> >     links from the consumer to the actual resource's device (if it has one,
> >     Eg: gpio_device) instead of the parent supplier device. This improves
> >     things like async suspend/resume ordering, potentially remove the need
> >     for frameworks to create device links, more parallelized async probing,
> >     and better sync_state() tracking.
> >
> > 3. Handle hardware/software quirks where a child firmware node gets
> >     populated as a device before its parent firmware node AND actually
> >     supplies a non-optional resource to the parent firmware node's
> >     device.
> >
> > 4. Way more robust at cycle handling (see patch for the insane cases).
> >
> > 5. Stops depending on OF_POPULATED to figure out some corner cases.
> >
> > 6. Simplifies the work that needs to be done by the firmware specific
> >     code.
> >
> > The v3 series has gone through my usual testing on my end and looks good
> > to me.
>
> Saravana,
>
> Please excuse me, I was completely overwhelmed with my regular work and
> had no time to properly test the series, while doing just the light
> test would defeat the purpose of testing.
>
> Tested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> # Qualcomm RB3
>
> Thanks a lot for going through all the troubles and hunting all the issues!

You are welcome! Thanks for testing it.

> Just a note: on an RB3 device (arm64 qcom/sdm845-db845c.dtsi) extended
> with the patch at [3] I got the following messages in dmesg:
>
> [    1.051325] platform ae00000.mdss: Failed to create device link
> with ae00000.mdss
> [    1.059368] platform ae00000.mdss: Failed to create device link
> with ae00000.mdss
> [    1.067174] platform ae00000.mdss: Failed to create device link
> with ae00000.mdss
> [    1.088322] platform c440000.spmi: Failed to create device link
> with c440000.spmi
> [    1.096019] platform c440000.spmi: Failed to create device link
> with c440000.spmi
> [    1.103707] platform c440000.spmi: Failed to create device link
> with c440000.spmi
> [    1.111400] platform c440000.spmi: Failed to create device link
> with c440000.spmi
> [    1.119141] platform c440000.spmi: Failed to create device link
> with c440000.spmi
> [    1.126825] platform c440000.spmi: Failed to create device link
> with c440000.spmi
> [    2.024763] qcom-lab-ibb-regulator c440000.spmi:pmic@3:labibb:
> Failed to create device link with c440000.spmi
> [    2.035026] qcom-lab-ibb-regulator c440000.spmi:pmic@3:labibb:
> Failed to create device link with c440000.spmi
>
> They look to be harmless, but it might be good to filter some of them
> out? Especially the ones which tell about creating a device link
> pointing back to the same device.

I'm sure it's harmless when the supplier == consumer. Agreed on
filtering these out.

I looked at [3], but it's not obvious to me how this is happening for
your specific case. There are a couple of  ways I can think of:
1. A SYNC_STATE_ONLY link being created as a proxy link (I don't do as
many checks here because it can't break anything)
2. __fw_devlink_pickup_dangling_consumers() causing the consumer and
supplier to be the same.

But I want to understand which one is happening in your case. Can you
add a WARN_ON(1) after the error message and give me the list of stack
dumps that are unique?

Thanks,
Saravana


>
> [3] https://lore.kernel.org/linux-arm-msm/20230118082048.2198715-1-dmitry.baryshkov@linaro.org/
>
> >
> > Thanks,
> > Saravana
> >
> > [1] - https://lore.kernel.org/lkml/20220810060040.321697-1-saravanak@google.com/
> > [2] - https://lore.kernel.org/lkml/CAGETcx-JUV1nj8wBJrTPfyvM7=Mre5j_vkVmZojeiumUGG6QZQ@mail.gmail.com/
> >
> > v1 -> v2:
> > - Fixed Patch 1 to handle a corner case discussed in [2].
> > - New patch 10 to handle "fsl,imx8mq-gpc" being initialized by 2 drivers.
> > - New patch 11 to add fw_devlink support for SCMI devices.
> >
> > v2 -> v3:
> > - Addressed most of Andy's comments in v2
> > - Added Colin and Sudeep's Tested-by for the series (except the imx and
> >    renesas patches)
> > - Added Sudeep's Acked-by for the scmi patch.
> > - Added Geert's Reviewed-by for the renesas patch.
> > - Fixed gpiolib crash reported by Naresh.
> > - Patch 6: Fix __fwnode_links_move_consumers() to preserve fwnode link flags.
> > - New Patch 12 to fix nvmem-cells issue reported by Maxim(s)/Miquel.
> > - Deleted some stale function doc in Patch 8
> >
> > Cc: Abel Vesa <abel.vesa@linaro.org>
> > Cc: Alexander Stein <alexander.stein@ew.tq-group.com>
> > Cc: Tony Lindgren <tony@atomide.com>
> > Cc: Sudeep Holla <sudeep.holla@arm.com>
> > Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> > Cc: John Stultz <jstultz@google.com>
> > Cc: Doug Anderson <dianders@chromium.org>
> > Cc: Guenter Roeck <linux@roeck-us.net>
> > Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > Cc: Maxim Kiselev <bigunclemax@gmail.com>
> > Cc: Maxim Kochetkov <fido_max@inbox.ru>
> > Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> > Cc: Luca Weiss <luca.weiss@fairphone.com>
> > Cc: Colin Foster <colin.foster@in-advantage.com>
> > Cc: Martin Kepplinger <martin.kepplinger@puri.sm>
> > Cc: Jean-Philippe Brucker <jpb@kernel.org>
> > Cc: Vladimir Oltean <vladimir.oltean@nxp.com>
> >
> > Saravana Kannan (12):
> >    driver core: fw_devlink: Don't purge child fwnode's consumer links
> >    driver core: fw_devlink: Improve check for fwnode with no
> >      device/driver
> >    soc: renesas: Move away from using OF_POPULATED for fw_devlink
> >    gpiolib: Clear the gpio_device's fwnode initialized flag before adding
> >    driver core: fw_devlink: Add DL_FLAG_CYCLE support to device links
> >    driver core: fw_devlink: Allow marking a fwnode link as being part of
> >      a cycle
> >    driver core: fw_devlink: Consolidate device link flag computation
> >    driver core: fw_devlink: Make cycle detection more robust
> >    of: property: Simplify of_link_to_phandle()
> >    irqchip/irq-imx-gpcv2: Mark fwnode device as not initialized
> >    firmware: arm_scmi: Set fwnode for the scmi_device
> >    mtd: mtdpart: Don't create platform device that'll never probe
> >
> >   drivers/base/core.c             | 449 +++++++++++++++++++++-----------
> >   drivers/firmware/arm_scmi/bus.c |   3 +-
> >   drivers/gpio/gpiolib.c          |   7 +
> >   drivers/irqchip/irq-imx-gpcv2.c |   1 +
> >   drivers/mtd/mtdpart.c           |  10 +
> >   drivers/of/property.c           |  84 +-----
> >   drivers/soc/imx/gpcv2.c         |   2 +-
> >   drivers/soc/renesas/rcar-sysc.c |   2 +-
> >   include/linux/device.h          |   1 +
> >   include/linux/fwnode.h          |  12 +-
> >   10 files changed, 344 insertions(+), 227 deletions(-)
> >
>
> --
> With best wishes
>
> Dmitry