From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Saravana Kannan <saravanak@google.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Len Brown <lenb@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
Marc Zyngier <maz@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Tomi Valkeinen <tomi.valkeinen@ti.com>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Grygorii Strashko <grygorii.strashko@ti.com>,
Android Kernel Team <kernel-team@android.com>,
ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-efi <linux-efi@vger.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>
Subject: Re: [PATCH v1 15/18] of: property: Update implementation of add_links() to create fwnode links
Date: Fri, 6 Nov 2020 08:22:47 +0100 [thread overview]
Message-ID: <20201106072247.GB2614221@kroah.com> (raw)
In-Reply-To: <CAGETcx-0TPte6g3Cf5F3WJwdW-9yUptLDj3AcEdvWN0YJ2H4qg@mail.gmail.com>
On Thu, Nov 05, 2020 at 03:25:56PM -0800, Saravana Kannan wrote:
> On Thu, Nov 5, 2020 at 1:41 AM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > On Wed, Nov 04, 2020 at 03:23:52PM -0800, Saravana Kannan wrote:
> > > The semantics of add_links() has changed from creating device link
> > > between devices to creating fwnode links between fwnodes. So, update the
> > > implementation of add_links() to match the new semantics.
> > >
> > > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > > ---
> > > drivers/of/property.c | 150 ++++++++++++------------------------------
> > > 1 file changed, 41 insertions(+), 109 deletions(-)
> > >
> > > diff --git a/drivers/of/property.c b/drivers/of/property.c
> > > index 408a7b5f06a9..86303803f1b3 100644
> > > --- a/drivers/of/property.c
> > > +++ b/drivers/of/property.c
> > > @@ -1038,33 +1038,9 @@ static bool of_is_ancestor_of(struct device_node *test_ancestor,
> > > }
> > >
> > > /**
> > > - * of_get_next_parent_dev - Add device link to supplier from supplier phandle
> > > - * @np: device tree node
> > > - *
> > > - * Given a device tree node (@np), this function finds its closest ancestor
> > > - * device tree node that has a corresponding struct device.
> > > - *
> > > - * The caller of this function is expected to call put_device() on the returned
> > > - * device when they are done.
> > > - */
> > > -static struct device *of_get_next_parent_dev(struct device_node *np)
> > > -{
> > > - struct device *dev = NULL;
> > > -
> > > - of_node_get(np);
> > > - do {
> > > - np = of_get_next_parent(np);
> > > - if (np)
> > > - dev = get_dev_from_fwnode(&np->fwnode);
> > > - } while (np && !dev);
> > > - of_node_put(np);
> > > - return dev;
> > > -}
> > > -
> > > -/**
> > > - * of_link_to_phandle - Add device link to supplier from supplier phandle
> > > - * @dev: consumer device
> > > - * @sup_np: phandle to supplier device tree node
> > > + * of_link_to_phandle - Add fwnode link to supplier from supplier phandle
> > > + * @con_np: consumer device tree node
> > > + * @sup_np: supplier device tree node
> > > *
> > > * Given a phandle to a supplier device tree node (@sup_np), this function
> > > * finds the device that owns the supplier device tree node and creates a
> > > @@ -1074,16 +1050,14 @@ static struct device *of_get_next_parent_dev(struct device_node *np)
> > > * cases, it returns an error.
> > > *
> > > * Returns:
> > > - * - 0 if link successfully created to supplier
> > > - * - -EAGAIN if linking to the supplier should be reattempted
> > > + * - 0 if fwnode link successfully created to supplier
> > > * - -EINVAL if the supplier link is invalid and should not be created
> > > - * - -ENODEV if there is no device that corresponds to the supplier phandle
> > > + * - -ENODEV if struct device will never be create for supplier
> > > */
> > > -static int of_link_to_phandle(struct device *dev, struct device_node *sup_np,
> > > - u32 dl_flags)
> > > +static int of_link_to_phandle(struct device_node *con_np,
> > > + struct device_node *sup_np)
> > > {
> > > - struct device *sup_dev, *sup_par_dev;
> > > - int ret = 0;
> > > + struct device *sup_dev;
> > > struct device_node *tmp_np = sup_np;
> > >
> > > of_node_get(sup_np);
> > > @@ -1106,7 +1080,8 @@ static int of_link_to_phandle(struct device *dev, struct device_node *sup_np,
> > > }
> > >
> > > if (!sup_np) {
> > > - dev_dbg(dev, "Not linking to %pOFP - No device\n", tmp_np);
> > > + pr_debug("Not linking %pOFP to %pOFP - No device\n",
> > > + con_np, tmp_np);
> >
> > Who is calling this function without a valid dev pointer?
>
> Sorry, I plan to delete the "dev" parameter as it's not really used
> anywhere. I'm trying to do that without causing build time errors and
> making the series into digestible small patches.
>
> I can do the deletion of the parameter as a Patch 19/19. Will that work?
That's fine, but why get rid of dev? The driver core works on these
things, and we want errors/messages/warnings to spit out what device is
causing those issues. It is fine to drag around a struct device pointer
just for messages, that's to be expected, and is good.
> > And the only way it can be NULL is if fwnode is NULL, and as you control
> > the callers to it, how can that be the case?
>
> fwnode represents a generic firmware node. The to_of_node() returns
> NULL if fwnode is not a DT node. So con_np can be NULL if that
> happens. That's why we need a NULL check here. With the current code,
> that can never happen, bit I think it doesn't hurt to check in case
> there's a buggy caller. I don't have a strong opinion - so I can do it
> whichever way.
If it can't happen, no need to check for it :)
thanks,
greg k-h
next prev parent reply other threads:[~2020-11-06 7:22 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-04 23:23 [PATCH v1 00/18] Refactor fw_devlink to significantly improve boot time Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 01/18] Revert "driver core: Avoid deferred probe due to fw_devlink_pause/resume()" Saravana Kannan
2020-11-05 9:34 ` Greg Kroah-Hartman
2020-11-05 23:19 ` Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 02/18] Revert "driver core: Rename dev_links_info.defer_sync to defer_hook" Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 03/18] Revert "driver core: Don't do deferred probe in parallel with kernel_init thread" Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 04/18] Revert "driver core: Remove check in driver_deferred_probe_force_trigger()" Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 05/18] Revert "of: platform: Batch fwnode parsing when adding all top level devices" Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 06/18] Revert "driver core: fw_devlink: Add support for batching fwnode parsing" Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 07/18] driver core: Add fwnode_init() Saravana Kannan
2020-11-05 9:36 ` Greg Kroah-Hartman
2020-11-05 23:20 ` Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 08/18] driver core: Add fwnode link support Saravana Kannan
2020-11-16 15:51 ` Rafael J. Wysocki
2020-11-21 1:59 ` Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 09/18] driver core: Allow only unprobed consumers for SYNC_STATE_ONLY device links Saravana Kannan
2020-11-16 15:57 ` Rafael J. Wysocki
2020-11-21 1:59 ` Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 10/18] device property: Add fwnode_is_ancestor_of() Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 11/18] driver core: Redefine the meaning of fwnode_operations.add_links() Saravana Kannan
2020-11-16 16:16 ` Rafael J. Wysocki
2020-11-21 1:59 ` Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 12/18] driver core: Add fw_devlink_parse_fwtree() Saravana Kannan
2020-11-16 16:25 ` Rafael J. Wysocki
2020-11-21 2:00 ` Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 13/18] driver core: Add fwnode_get_next_parent_dev() helper function Saravana Kannan
2020-11-16 16:27 ` Rafael J. Wysocki
2020-11-21 2:00 ` Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 14/18] driver core: Use device's fwnode to check if it is waiting for suppliers Saravana Kannan
2020-11-16 16:34 ` Rafael J. Wysocki
2020-11-21 2:00 ` Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 15/18] of: property: Update implementation of add_links() to create fwnode links Saravana Kannan
2020-11-05 9:42 ` Greg Kroah-Hartman
2020-11-05 23:25 ` Saravana Kannan
2020-11-06 1:24 ` Saravana Kannan
2020-11-06 7:22 ` Greg Kroah-Hartman [this message]
2020-11-06 7:41 ` Saravana Kannan
2020-11-06 7:51 ` Greg Kroah-Hartman
2020-11-06 8:29 ` Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 16/18] efi: " Saravana Kannan
2020-11-05 9:43 ` Greg Kroah-Hartman
2020-11-05 23:27 ` Saravana Kannan
2020-11-06 6:45 ` Greg Kroah-Hartman
2020-11-04 23:23 ` [PATCH v1 17/18] driver core: Add helper functions to convert fwnode links to device links Saravana Kannan
2020-11-05 9:43 ` Greg Kroah-Hartman
2020-11-05 23:32 ` Saravana Kannan
2020-11-06 7:24 ` Greg Kroah-Hartman
2020-11-06 7:43 ` Saravana Kannan
2020-11-16 16:57 ` Rafael J. Wysocki
2020-11-21 2:00 ` Saravana Kannan
2020-11-04 23:23 ` [PATCH v1 18/18] driver core: Refactor fw_devlink feature Saravana Kannan
2020-11-04 23:26 ` [PATCH v1 00/18] Refactor fw_devlink to significantly improve boot time Saravana Kannan
2020-11-06 5:09 ` Laurent Pinchart
2020-11-06 8:36 ` Saravana Kannan
2020-11-06 12:46 ` Grygorii Strashko
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