From: Peter Mamonov <pmamonov@gmail.com>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Barebox List <barebox@lists.infradead.org>
Subject: Re: [PATCH] Pass barebox version to kernel
Date: Tue, 27 Feb 2018 22:43:59 +0300 [thread overview]
Message-ID: <20180227194358.bpppmhqcunm2gb6a@localhost> (raw)
In-Reply-To: <20180227083430.ze66vwf42ytipjsf@pengutronix.de>
On Tue, Feb 27, 2018 at 09:34:30AM +0100, Sascha Hauer wrote:
> Hi Peter,
>
> On Mon, Feb 26, 2018 at 01:12:02PM +0300, Peter Mamonov wrote:
> > Hi, Sasha,
> >
> > On Mon, Feb 26, 2018 at 09:23:49AM +0100, Sascha Hauer wrote:
> > > When userspace is interested in the barebox version it has currently no
> > > way of reliably reading it. Add it to the kernel command line as it's an
> > > established way to pass information from the bootloader to the kernel.
> > > If CONFIG_FLEXIBLE_BOOTARGS is enabled then the barebox version is
> > > passed in the "bootloader.version=" variable.
> >
> > Some time ago we solved a similar problem: a number of parameters including
> > barebox version, MAC address (which may be random due to the lack of a NIC
> > EEPROM) and some vendor specific parameters are passed to the kernel via DTB.
> > A dedicated command was implemented which can either patch the existing DTB or
> > generate an overlay DTB. In the latter case the overlay DTB is passed to the
> > kernel with the help of a new `bootm` option. Of course the latter approach
> > requires support on the kernel side.
>
> We could of course pass the barebox version in the /chosen node. That
> would require a of_register_fixup(). Why would we need an extra command
> for that?
Well, it allows some extra flexibility: either original DTB is patched or a
separate DTB blob is generated. However there is no strict need for a command.
My actual point is that passing various bootloader stuff to a kernel via DTB
feels like a cleaner solution, rather than using kernel cmdline for that
purpose.
Regards,
Peter
> The MAC address should already be inserted into the kernel device tree
> automatically.
>
> Sascha
>
> --
> Pengutronix e.K. | |
> Industrial Linux Solutions | http://www.pengutronix.de/ |
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next prev parent reply other threads:[~2018-02-27 19:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-26 8:23 Sascha Hauer
2018-02-26 10:12 ` Peter Mamonov
2018-02-27 8:34 ` Sascha Hauer
2018-02-27 19:43 ` Peter Mamonov [this message]
2018-02-28 7:34 ` Sascha Hauer
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