From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marek Vasut <marek.vasut@gmail.com>
Date: Wed, 25 Jan 2012 21:55:53 +0100
Subject: [U-Boot] [PATCH 02/14] arm: Optionally use existing atags in
	bootm.c
In-Reply-To: <8793911.71VDepJcRE@pali>
References: <1327415291-13260-1-git-send-email-pali.rohar@gmail.com>
	<201201251902.45932.marek.vasut@gmail.com>
	<8793911.71VDepJcRE@pali>
Message-ID: <201201252155.53860.marek.vasut@gmail.com>
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To: u-boot@lists.denx.de

> On Wednesday 25 January 2012 19:02:45 Marek Vasut wrote:
> > > This patch adapts the bootm command so that it can use an existing
> > > atags command set up by a previous bootloader.
> > 
> > Why do you need it?
> 
> Default Nokia kernel has patches which using non-standard atags for
> reporting bootmode, bootreason, hw-rev, NOLO version, boot count, ...

So what? Make u-boot pass arbitrary atags and specify them in your board file.

> 
> Closed-source Maemo application need to know these properties (read via
> /proc/bootreason, ...) and will restart device if there is error.

Fine?
> 
> So U-Boot must can reuse old atags from NOLO and tell it new kernel.

must can reuse? Anyway, that's nonsense, why won't u-boot be able to craft those 
atags?

> 
> > > If the environment variable
> > > "atagaddr" is unset, bootm behaves as normal. If "atagaddr" is set,
> > > bootm will use atags address from environment variable and also append
> > > new boot args (if specified in u-boot). For example, if a previous
> > > boot loader already set up the atags struct at 0x80000100:
> > > 
> > > setenv atagaddr 0x80000100; bootm 0x80008000
> > 
> > Can't you set those atags correctly in uboot?
> 
> No, because atags are not static (e.g bootreason).

So? You craft them properly in u-boot?

M