linux-kernel - Re: [PATCH 00/11] platform: device tree support for early platform drivers

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: <CAL_JsqLcoPK-dDWjwrS82RRG-WLKePfDgHJcBKRQWZG5PszrKg@mail.gmail.com>
Date:   Tue, 24 Apr 2018 14:39:44 -0500
From:   Rob Herring <robh+dt@...nel.org>
To:     Bartosz Golaszewski <brgl@...ev.pl>
Cc:     Sekhar Nori <nsekhar@...com>, Kevin Hilman <khilman@...nel.org>,
        David Lechner <david@...hnology.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Mark Rutland <mark.rutland@....com>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Rich Felker <dalias@...c.org>,
        Frank Rowand <frowand.list@...il.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Arend van Spriel <aspriel@...il.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Michal Suchanek <msuchanek@...e.de>,
        Jan Kiszka <jan.kiszka@...mens.com>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        devicetree@...r.kernel.org,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH 00/11] platform: device tree support for early platform drivers

On Tue, Apr 24, 2018 at 12:30 PM, Bartosz Golaszewski <brgl@...ev.pl> wrote:
> From: Bartosz Golaszewski <bgolaszewski@...libre.com>
>
> Device tree based systems often use OF_DECLARE() macros for devices
> that need to be initialized early in the boot process such as clocks,
> timers etc. However platform devices are more desirable.

Yes, platform devices would be more desirable, but ...
>
> This series aims at introducing support for early platform drivers for
> OF-based systems.

... the whole early_platform_device infrastructure is not really a
platform_device. Rather it kind of looks like one and I guess gets
converted over during boot.

This is not the first attempt to add DT support to early platform
devices[1]. I think the same objections still apply. It has been
pretty much only an SH thing (which as an arch, I'm told is pretty
much unmaintained and broken).

> The idea is to have a special compatible fallback string: "earlydev"
> that similarily to "syscon" would be added to device nodes that need
> early probing. We then need to call of_early_platform_populate() early
> in the boot process to actually probe the registered devices.

Others have sufficiently explained why this won't fly for DT, so I
don't have more to add.

Rob

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2011-June/054529.html