linux-kernel - Re: [PATCH v4 11/18] device property: Add remote endpoint to devcon matcher

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ZtWdsZrFxfjYLgaG@smile.fi.intel.com>
Date: Mon, 2 Sep 2024 14:12:49 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Stephen Boyd <swboyd@...omium.org>
Cc: chrome-platform@...ts.linux.dev, linux-kernel@...r.kernel.org,
	patches@...ts.linux.dev, devicetree@...r.kernel.org,
	Douglas Anderson <dianders@...omium.org>,
	Pin-yen Lin <treapking@...omium.org>,
	Andrzej Hajda <andrzej.hajda@...el.com>,
	Benson Leung <bleung@...omium.org>,
	Conor Dooley <conor+dt@...nel.org>, Daniel Vetter <daniel@...ll.ch>,
	David Airlie <airlied@...il.com>,
	Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
	dri-devel@...ts.freedesktop.org,
	Guenter Roeck <groeck@...omium.org>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Jonas Karlman <jonas@...boo.se>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
	Lee Jones <lee@...nel.org>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Prashant Malani <pmalani@...omium.org>,
	Robert Foss <rfoss@...nel.org>, Rob Herring <robh+dt@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	Tzung-Bi Shih <tzungbi@...nel.org>,
	Alexandre Belloni <alexandre.belloni@...tlin.com>,
	Daniel Scally <djrscally@...il.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
	Ivan Orlov <ivan.orlov0322@...il.com>, linux-acpi@...r.kernel.org,
	linux-usb@...r.kernel.org,
	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
	Sakari Ailus <sakari.ailus@...ux.intel.com>,
	Vinod Koul <vkoul@...nel.org>
Subject: Re: [PATCH v4 11/18] device property: Add remote endpoint to devcon
 matcher

On Sat, Aug 31, 2024 at 09:06:49PM -0700, Stephen Boyd wrote:
> When a single DT node has a graph connected to more than one
> usb-c-connector node we can't differentiate which typec switch
> registered for the device is associated with the USB connector because
> the devcon matcher code assumes a 1:1 relationship between remote node
> and typec switch. Furthermore, we don't have a #typec-switch-cells
> property so there can only be one node per typec switch.
> 
> Support multiple USB typec switches exposed by one node by passing the
> remote endpoint node in addition to the remote node to the devcon
> matcher function (devcon_match_fn_t). With this change, typec switch
> drivers can register switches with the device node pointer for a graph
> endpoint so that they can support more than one typec switch if
> necessary. Either way, a DT property like 'mode-switch' is always in the
> graph's parent node and not in the endpoint node.

> Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Cc: Daniel Scally <djrscally@...il.com>
> Cc: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
> Cc: Sakari Ailus <sakari.ailus@...ux.intel.com>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: Vinod Koul <vkoul@...nel.org>
> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
> Cc: Mika Westerberg <mika.westerberg@...ux.intel.com>
> Cc: Alexandre Belloni <alexandre.belloni@...tlin.com>
> Cc: Ivan Orlov <ivan.orlov0322@...il.com>
> Cc: Rob Herring <robh+dt@...nel.org>
> Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>
> Cc: Conor Dooley <conor+dt@...nel.org>
> Cc: <devicetree@...r.kernel.org>
> Cc: <linux-usb@...r.kernel.org>
> Cc: <linux-acpi@...r.kernel.org>
> Cc: Pin-yen Lin <treapking@...omium.org>

Is it possible to move these Cc:s after --- line below?

> Signed-off-by: Stephen Boyd <swboyd@...omium.org>

...

>  /**
>   * devcon_match_fn_t - device connection match function
>   * @fwnode: Remote connection's device node
> + * @endpoint: Remote connection's endpoint node
>   * @con_id: Identifier for the connection
>   * @data: Match function caller specific data
>   *
>   * Implement a callback with this function signature to search a fwnode's
>   * connections for a match with a function like device_connection_find_match().
>   * This function will be called possibly multiple times, once for each
> - * connection. The match function should inspect the @fwnode to look for a
> - * match. The @con_id and @data provided are the same as the @con_id and @data
> - * arguments passed to the functions that take a devcon_match_fn_t argument.
> + * connection. The match function should inspect the connection's @fwnode
> + * and/or @endpoint to look for a match. The @con_id and @data provided are the
> + * same as the @con_id and @data arguments passed to the functions that take a
> + * devcon_match_fn_t argument.

So, struct fwnode_handle is a single-linked list. Can we utilise that instead
of adding a new parameter? I.o.w. do those objects (@fwnode and @endpoint) have
anything in common and can be chained?

>   * Note: This function can be called multiple times.

What does this mean? Is it idempotent? Or what is the effect of being called
multiple times?

>   *
>   * Return: Pointer to match or NULL if no match found.
>   */

-- 
With Best Regards,
Andy Shevchenko