From: Pali =?utf-8?q?Roh=C3=A1r?= <pali.rohar@gmail.com>
To: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>
Subject: Re: wl1251: NVS firmware data
Date: Thu, 27 Nov 2014 16:22:58 +0100
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Cc: Ming Lei <ming.lei@canonical.com>,
        "John W. Linville" <linville@tuxdriver.com>,
        Grazvydas Ignotas <notasas@gmail.com>,
        "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Pavel Machek <pavel@ucw.cz>,
        Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>,
        Aaro Koskinen <aaro.koskinen@iki.fi>, Kalle Valo <kvalo@adurom.com>,
        Sebastian Reichel <sre@ring0.de>,
        David Gnedt <david.gnedt@davizone.at>
References: <201411271506.20457@pali> <201411271543.23527@pali> <20141127151655.GB23064@kroah.com>
In-Reply-To: <20141127151655.GB23064@kroah.com>
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On Thursday 27 November 2014 16:16:55 Greg Kroah-Hartman wrote:
> On Thu, Nov 27, 2014 at 03:43:23PM +0100, Pali Roh=C3=A1r wrote:
> > On Thursday 27 November 2014 15:21:44 Ming Lei wrote:
> > > On Thu, Nov 27, 2014 at 10:06 PM, Pali Roh=C3=A1r
> >=20
> > <pali.rohar@gmail.com> wrote:
> > > > Hello,
> > > >=20
> > > > wifi driver wl1251 needs NVS calibration data for
> > > > working. These data are loaded by driver via
> > > > request_firmware from userspace file:
> > > > ti-connectivity/wl1251-nvs.bin. In linux-fimrware git
> > > > tree there is generic wl1251-nvs.bin file which is used
> > > > by default.
> > > >=20
> > > > Driver wl1251 is used on Nokia N900 cellphone for its
> > > > wifi chip. This cellphone has one special MTD partition
> > > > (called CAL) where are stored some configuration data
> > > > in special binary (key-value) format. And there is also
> > > > stored correct calibration data for specific device
> > > > (each device has different data). It is preferred to
> > > > use those data instead generic one (provided by
> > > > linux-firmware git tree).
> > > >=20
> > > > Now my question is: How to correctly load calibration
> > > > data from special Nokia N900 CAL partition into wl1251
> > > > kernel driver?
> > >=20
> > > It is better to let user space script handle the request.
> >=20
> > Yes, this makes sense. Implementing CAL parser in kernel
> > wl1251 driver would be hard...
> >=20
> > > > By default kernel reads ti-connectivity/wl1251-nvs.bin
> > > > file from VFS if exists without any userspace support.
> > > > If it fails then it fallback to loading via udev.
> > >=20
> > > You can remove or rename this file so that loading from
> > > user space can be triggered.
> >=20
> > It is no so easy... In case when CAL does not contains NVS
> > data then we want to use this generic NVS file. And telling
> > everybody to rename this is file is not good solution...
>=20
> But that's up to your system configuration, not the kernel.=20
> Make a userspace package for the firmware that creates it in
> the format you need it to be in, for the hardware you have,
> and then there would not be any need for a kernel change,
> right?
>=20
> greg k-h

Not so simple as you think. Some parts of NVS data are configured=20
based on location and cellular station. Data are not static.

=2D-=20
Pali Roh=C3=A1r
pali.rohar@gmail.com

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